RESUMO
This work further explores the possibilities for designing the high-temperature electrical performance of the thermoelectric Ca3Co4O9 phase, by a composite approach involving separate metallic iron and nickel particles additions, and by employing two different sintering schemes, capable to promote the controlled interactions between the components, encouraged by our recent promising results obtained for similar cobalt additions. Iron and nickel were chosen because of their similarities with cobalt. The maximum power factor value of around 200 µWm-1K-2 at 925 K was achieved for the composite with the nominal nickel content of 3% vol., processed via the two-step sintering cycle, which provides the highest densification from this work. The effectiveness of the proposed approach was shown to be strongly dependent on the processing conditions and added amounts of metallic particles. Although the conventional one-step approach results in Fe- and Ni-containing composites with the major content of the thermoelectric Ca3Co4O9 phase, their electrical performance was found to be significantly lower than for the Co-containing analogue, due to the presence of less-conducting phases and excessive porosity. In contrast, the relatively high performance of the composite with a nominal nickel content of 3% vol. processed via a two-step approach is related to the specific microstructural features from this sample, including minimal porosity and the presence of the Ca2Co2O5 phase, which partially compensate the complete decomposition of the Ca3Co4O9 matrix. The obtained results demonstrate different pathways to tailor the phase composition of Ca3Co4O9-based materials, with a corresponding impact on the thermoelectric performance, and highlight the necessity of more controllable approaches for the phase composition tuning, including lower amounts and different morphologies of the dispersed metallic phases.
RESUMO
One of the reasons for recurrence following treatment of high grade serous ovarian carcinoma (HGSOC) is the persistence of residual cancer stem cells (CSCs). There has been variability between laboratories in the identification of CSC markers for HGSOC. We have identified new surface markers (CD24, CD9 and EPHA1) in addition to those previously known (CD44, CD117 and CD133) using a bioinformatics approach. The expression of these surface markers was evaluated in ovarian cancer cell lines, primary malignant cells (PMCs), normal ovary and HGSOC. There was no preferential expression of any of the markers or a combination. All the markers were expressed at variable levels in ovarian cancer cell lines and PMCs. Only CD117 and CD9 were expressed in the normal ovarian surface epithelium and fallopian tube. Both ALDEFLUOR (ALDH1A1) and side population assays identified a small proportion of cells (<3%) separately that did not overlap with little variability in cell lines and PMCs. All surface markers were co-expressed in ALDH1A1+ cells without preference for one combination. The cell cycle analysis of ALDH1A1+ cells alone revealed that majority of them reside in G0/G1 phase of cell cycle. Further separation of G0 and G1 phases showed that ALDH1A1+ cells reside in G1 phase of the cell cycle. Xenograft assays showed that the combinations of ALDH1A1 + cells co-expressing CD9, CD24 or EPHA1 were more tumorigenic and aggressive with respect to ALDH1A1-cells. These data suggest that a combined approach could be more useful in identifying CSCs in HGSOC.
Assuntos
Família Aldeído Desidrogenase 1/metabolismo , Biomarcadores Tumorais/metabolismo , Cistadenocarcinoma Seroso/patologia , Células-Tronco Neoplásicas/fisiologia , Neoplasias Ovarianas/patologia , Retinal Desidrogenase/metabolismo , Família Aldeído Desidrogenase 1/genética , Animais , Antígenos de Superfície/genética , Antígenos de Superfície/metabolismo , Biomarcadores Tumorais/genética , Antígeno CD24/genética , Antígeno CD24/metabolismo , Linhagem Celular Tumoral , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/metabolismo , Cistadenocarcinoma Seroso/genética , Cistadenocarcinoma Seroso/metabolismo , Feminino , Xenoenxertos , Humanos , Camundongos , Camundongos Nus , Camundongos Transgênicos , Invasividade Neoplásica , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neoplásicas/patologia , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/metabolismo , Receptor EphA1/genética , Receptor EphA1/metabolismo , Retinal Desidrogenase/genética , Tetraspanina 29/genética , Tetraspanina 29/metabolismoRESUMO
Ab initio composite approaches have been utilized to model and predict main group thermochemistry within 1 kcal mol-1 , on average, from well-established reliable experiments, primarily for molecules with less than 30 atoms. For molecules of increasing size and complexity, such as biomolecular complexes, composite methodologies have been limited in their application. Therefore, the domain-based local pair natural orbital (DLPNO) methods have been implemented within the correlation consistent composite approach (ccCA) framework, namely DLPNO-ccCA, to reduce the computational cost (disk space, CPU (central processing unit) time, memory) and predict energetic properties such as enthalpies of formation, noncovalent interactions, and conformation energies for organic biomolecular complexes including one of the largest molecules examined via composite strategies, within 1 kcal mol-1 , after calibration with 119 molecules and a set of linear alkanes. © 2019 Wiley Periodicals, Inc.