Emerging Translational Opportunities in Comparative Oncology With Companion Canine Cancers: Radiation Oncology.

It is estimated that more than 6 million pet dogs are diagnosed with cancer annually in the USA. Both primary care and specialist veterinarians are frequently called upon to provide clinical care that improves the quality and/or quantity of life for affected animals. Because these cancers develop spontaneously in animals that often share the same environment as their owners, have intact immune systems and are of similar size to humans, and because the diagnostic tests and treatments for these cancers are similar to those used for management of human cancers, canine cancer provides an opportunity for research that simultaneously helps improve both canine and human health care. This is especially true in the field of radiation oncology, for which there is a rich and continually evolving history of learning from the careful study of pet dogs undergoing various forms of radiotherapy. The purpose of this review article is to inform readers of the potential utility and limitations of using dogs in that manner; the peer-reviewed literature will be critically reviewed, and current research efforts will be discussed. The article concludes with a look toward promising future directions and applications of this pet dog "model.

Relative Income, Redistribution and Well-being

In a model with heterogeneous workers and both intensive and extensive margins of employment, we consider two systems of redistribution: a universal basic income, and a categorical unemployment benefit. Well-being depends on own-consumption relative to average employed workers’ consumption, and concern for relativity is a parameter that affects model outcomes. While labour supply incurs positive marginal disutility, we allow negative welfare effects of unemployment. We also compare Rawlsian and utilitarian welfare in general equilibrium under the polar opposite transfer systems, with varying concern for relativity. Basic income Pareto dominates categorical benefits with moderate concern for relativity in both cases.relative income, redistribution, basic income, unemployment benefits, happiness, well-being

Charge compensation and Ce3+ formation in trivalent doping of the CeO2(110) surface: The key role of dopant ionic radius

In this paper, we use density functional theory corrected for on-site Coulomb interactions (DFT + U) and hybrid DFT (HSE06 functional) to study the defects formed when the ceria (110) surface is doped with a series of trivalent dopants, namely, Al3+, Sc3+, Y3+, and In 3+. Using the hybrid DFT HSE06 exchange-correlation functional as a benchmark, we show that doping the (110) surface with a single trivalent ion leads to formation of a localized MCe / + O O • (M = the 3+ dopant), O- hole state, confirming the description found with DFT + U. We use DFT + U to investigate the energetics of dopant compensation through formation of the 2MCe ′ +VO ̈ defect, that is, compensation of two dopants with an oxygen vacancy. In conjunction with earlier work on La-doped CeO2, we find that the stability of the compensating anion vacancy depends on the dopant ionic radius. For Al3+, which has the smallest ionic radius, and Sc3+ and In3+, with intermediate ionic radii, formation of a compensating oxygen vacancy is stable. On the other hand, the Y3+ dopant, with an ionic radius close to that of Ce4+, shows a positive anion vacancy formation energy, as does La3+, which is larger than Ce4+ (J. Phys.: Condens. Matter 2010, 20, 135004). When considering the resulting electronic structure, in Al3+ doping, oxygen hole compensation is found. However, Sc 3+, In3+, and Y3+ show the formation of a reduced Ce3+ cation and an uncompensated oxygen hole, similar to La3+. These results suggest that the ionic radius of trivalent dopants strongly influences the final defect formed when doping ceria with 3+ cations. In light of these findings, experimental investigations of these systems will be welcome

Surface modification of TiO2 with metal oxide nanoclusters: a route to composite photocatalytic materials

Density functional theory simulations show that modifying rutile TiO2 with metal oxide nanoclusters produces composite materials with potential visible light photocatalytic activity

Enhanced oxygen vacancy formation in ceria (111) and (110) surfaces doped with divalent cations

With increasing interest in new catalytic materials based on doping of cerium dioxide with other metal cations, it is necessary to have an atomic level understanding of the factors that impact on the structural and electronic properties of doped ceria as well as its reactivity. We present in this paper simulations of the ceria (111) and (110) surfaces doped with divalent cations Pd and Ni using density functional theory (DFT) corrected for on-site Coulomb interactions (DFT + U) and hybrid DFT (using the screened exchange HSE06 functional). Structural distortions due to doping are strong in both surfaces and the most stable structure for both dopants arises through compensation of the dopant + 2 valence through oxygen vacancy formation. Both dopants also lower the formation energy of the active oxygen vacancy in each surface, confirming the potential for these dopants to be used in ceria based materials for catalysis or solid oxide fuel cells, where the oxygen vacancy formation energy is important. When comparing DFT + U and hybrid DFT, although the qualitative descriptions provided by both DFT approaches are similar, we do find that the energetics of oxygen vacancy formation are quantitatively different and the importance of this point is discussed

Formation of Ce3+ at the cerium dioxide (110) surface by doping

The formation of Ce3+ ions in CeO2 is key for its applications. We present density functional theory (DFT) studies of doping of the CeO2 (1 1 0) surface with +5 cations, Ta and Nb, as a route to formation of Ce3+. We use DFT corrected for on-site Coulomb interactions (DFT + U, U = 5 eV) and hybrid DFT (HSE06 functional). With both methods we find formation of Ce3+ ions due to the extra electron from the dopant residing on a single Ce site, confirming the DFT + U description of these systems. Doping with Nb and Ta activates the surface to NO2 reduction – there is no interaction with the undoped surface but the Ce3+ ion in the doped surface interacts strongly with NO2

Lead oxide-modified TiO2 photocatalyst: tuning light absorption and charge carrier separation by lead oxidation state

Modification of TiO2 with metal oxide nanoclusters such as FeOx, NiOx has been shown to be a promising approach to the design of new photocatalysts with visible light absorption and improved electron–hole separation. To study further the factors that determine the photocatalytic properties of structures of this type, we present in this paper a first principles density functional theory (DFT) investigation of TiO2 rutile(110) and anatase(001) modified with PbO and PbO2 nanoclusters, with Pb2+ and Pb4+ oxidation states. This allows us to unravel the effect of the Pb oxidation state on the photocatalytic properties of PbOx-modified TiO2. The nanoclusters adsorb strongly at all TiO2 surfaces, creating new Pb–O and Ti–O interfacial bonds. Modification with PbO and PbO2 nanoclusters introduces new states in the original band gap of rutile and anatase. However the oxidation state of Pb has a dramatic impact on the nature of the modifications of the band edges of TiO2 and on the electron–hole separation mechanism. PbO nanocluster modification leads to an upwards shift of the valence band which reduces the band gap and upon photoexcitation results in hole localisation on the PbO nanocluster and electron localisation on the surface. By contrast, for PbO2 nanocluster modification the hole will be localised on the TiO2 surface and the electron on the nanocluster, thus giving rise to two different band gap reduction and electron–hole separation mechanisms. We find no crystal structure sensitivity, with both rutile and anatase surfaces showing similar properties upon modification with PbOx. In summary the photocatalytic properties of heterostructures of TiO2 with oxide nanoclusters can be tuned by oxidation state of the modifying metal oxide, with the possibility of a reduced band gap causing visible light activation and a reduction in charge carrier recombination

Doping of ceria surfaces with lanthanum: a DFT plus U study

In this paper we use density functional theory corrected for on-site Coulomb interactions (DFT + U) to study the defects formed in the ceria (111) and (110) surfaces doped with La. To describe consistently the defect formed with substitutional La(3+) doping at a Ce(4+) site we use DFT and DFT + U, with U = 5 eV for Ce 4f states and U = 7 eV for O 2p states. When La(3+) substitutes on a Ce(3+) site, an La(Ce)' + O(O)(center dot) defect state, with an oxygen hole, is formed at both surfaces, but only with the DFT + U approach. The formation energy of an oxygen vacancy in a structure with two La dopants in their most stable distribution is reduced over the undoped surfaces but remains positive. Formation of an oxygen vacancy results in the appearance of a reduced Ce(3+) cation and a compensated oxygen hole, instead of compensation of both oxygen holes, which is typical of metal oxides doped with lower valence cations. We tentatively suggest that the key role in the formation of this unusual defect is played by cerium and arises from the ease with which cerium can be reduced, as compared to other metal oxides. Experimental confirmation of these results is suggested

Reactivity of sub 1 nm supported clusters: (TiO2)(n) clusters supported on rutile TiO2 (110)

Metal oxide clusters of sub-nm dimensions dispersed on a metal oxide support are an important class of catalytic materials for a number of key chemical reactions, showing enhanced reactivity over the corresponding bulk oxide. In this paper we present the results of a density functional theory study of small sub-nm TiO2 clusters, Ti2O4, Ti3O6 and Ti4O8 supported on the rutile (110) surface. We find that all three clusters adsorb strongly with adsorption energies ranging from -3 eV to -4.5 eV. The more stable adsorption structures show a larger number of new Ti-O bonds formed between the cluster and the surface. These new bonds increase the coordination of cluster Ti and O as well as surface oxygen, so that each has more neighbours. The electronic structure shows that the top of the valence band is made up of cluster derived states, while the conduction band is made up of Ti 3d states from the surface, resulting in a reduction of the effective band gap and spatial separation of electrons and holes after photon absorption, which shows their potential utility in photocatalysis. To examine reactivity, we study the formation of oxygen vacancies in the cluster-support system. The most stable oxygen vacancy sites on the cluster show formation energies that are significantly lower than in bulk TiO2, demonstrating the usefulness of this composite system for redox catalysis