High-Throughput Screening of the Thermoelastic Properties of Ultrahigh-Temperature Ceramics.

Ultrahigh-temperature ceramics (UHTCs) are a group of materials with high technological interest because of their applications in extreme environments. However, their characterization at high temperatures represents the main obstacle for their fast development. Obstacles are found from an experimental point of view, where only few laboratories around the world have the resources to test these materials under extreme conditions, and also from a theoretical point of view, where actual methods are expensive and difficult to apply to large sets of materials.

Comprehensive Experimental and Theoretical Study of the CO + NO Reaction Catalyzed by Au/Ni Nanoparticles.

The catalytic and structural properties of five different nanoparticle catalysts with varying Au/Ni composition were studied by six different methods, including in situ X-ray absorption spectroscopy and density functional theory (DFT) calculations. The as-prepared materials contained substantial amounts of residual capping agent arising from the commonly used synthetic procedure. Thorough removal of this material by oxidation was essential for the acquisition of valid catalytic data.

Graphene Translucency and Interfacial Interactions in the Gold/Graphene/SiC System.

Integration of graphene into electronic circuits through its joining with conventional metal electrodes (i.e., gold) appears to be one of the main technological challenges nowadays.

AgS Quantum Dot-Sensitized Solar Cells by First Principles: The Effect of Capping Ligands and Linkers.

Quantum dots solar cells, QDSCs, are one of the candidates for being a reliable alternative to fossil fuels. However, the well-studied CdSe and CdTe-based QDSCs present a variety of issues for their use in consumer-goods applications. Silver sulfide, AgS, is a promising material, but poor efficiency has been reported for QDSCs based on this compound.

Adsorption of Prototypical Asphaltenes on Silica: First-Principles DFT Simulations Including Dispersion Corrections.

In this work, we explore the interaction between some prototypical asphaltene and porphyrin molecules with a fully hydroxylated (0001) surface of α-quartz by means of theoretical calculations based on the density functional theory (DFT) under periodic boundary conditions. The influence of dispersion forces, adsorption geometries, and size of the side chain is analyzed. The inclusion of London dispersion forces is overriding as they increase the interaction by about 1 order of magnitude.

Potassium and Water Coadsorption on TiO(110): OH-Induced Anchoring of Potassium and the Generation of Single-Site Catalysts.

Potassium deposition on TiO(110) results in reduction of the substrate and formation of loosely bound potassium species that can move easily on the oxide surface to promote catalytic activity. The results of density functional calculations predict a large adsorption energy (∼3.2 eV) with a small barrier (∼0.

Inverse Oxide/Metal Catalysts in Fundamental Studies and Practical Applications: A Perspective of Recent Developments.

Inverse oxide/metal catalysts have shown to be excellent systems for studying the role of the oxide and oxide-metal interface in catalytic reactions. These systems can have special structural and catalytic properties due to strong oxide-metal interactions difficult to attain when depositing a metal on a regular oxide support. Oxide phases that are not seen or are metastable in a bulk oxide can become stable in an oxide/metal system opening the possibility for new chemical properties.

Catalysis. Highly active copper-ceria and copper-ceria-titania catalysts for methanol synthesis from CO₂.

The transformation of CO2 into alcohols or other hydrocarbon compounds is challenging because of the difficulties associated with the chemical activation of CO2 by heterogeneous catalysts. Pure metals and bimetallic systems used for this task usually have low catalytic activity. Here we present experimental and theoretical evidence for a completely different type of site for CO2 activation: a copper-ceria interface that is highly efficient for the synthesis of methanol.

First-principles molecular dynamics simulations of the H2O/Cu(111) interface.

A first-principles theoretical study of the water-Cu(111) interface based on density functional calculations is reported. Using differently sized surface models: p(2 × 2), p(4 × 4) and p(4 × 5), we found out that the adsorption energy of a H(2)O monomer does not significantly change with the surface model though the adsorption geometry is sensitive to the choice of the super-cell surface and, also, to the coverage. Molecular dynamics simulations on the Born-Oppenheimer surface of liquid water on a Cu(111) surface reveal that H(2)O in the first solvent layer adsorbs O-down and that the H-bond network is weaker upon adsorption on the Cu.

First-principles study of ionic oxygen mobility of Sr-containing LaAlO(3) perovskite.

The fundamental phenomena underlying the electrical conduction properties of Sr-containing LaAlO(3) perovskites are studied through DFT simulations. The most energetically favourable substitution sites for Sr in the LaAlO(3) lattice and the energetic barriers for oxygen diffusion were calculated. Ab initio molecular dynamics was used to investigate the onset of oxygen transport.

Reactions of {[Pd(&mgr;-SC(6)F(5))(&mgr;-dppm)Pd](&mgr;-SC(6)F(5))}(4).2O(C(2)H(5))(2). Crystal Structures of the Complexes [(Ph(3)P)Pd(&mgr;-SC(6)F(5))(&mgr;-dppm)Pd(SC(6)F(5))].1.4CH(2)Cl(2) and [(Ph(3)P)Pd(&mgr;-SC(6)F(5))(&mgr;-dppm)Pd(PPh(3))]SO(3)CF(3).2CH(2)Cl(2) and ab Initio MO Calculations on the Model Systems [(H(3)P)Pd(&mgr;-H(2)PCH(2)PH(2))(&mgr;-SH)Pd(PH(3))](+) and [(H(3)P)Pd(&mgr;-H(2)PCH(2)PH(2))Pd(PH(3))](2+).

{[Pd(&mgr;-SC(6)F(5))(&mgr;-dppm)Pd](&mgr;-SC(6)F(5))}(4) reacts 1:4 with neutral ligands L to give [LPd(&mgr;-SC(6)F(5))(&mgr;-dppm)Pd(SC(6)F(5))] or 1:8 to form [LPd(&mgr;-SC(6)F(5))(&mgr;-dppm)PdL](+) (dppm = bis(diphenylphosphino)methane). These binuclear complexes retain the palladium-palladium bond and the two dissimilar bridging ligands, as demonstrated by the X-ray structural determinations carried out on [(Ph(3)P)Pd(&mgr;-SC(6)F(5))(&mgr;-dppm)Pd(SC(6)F(5))].1.

Cell types in the main excretory duct of the submaxillary gland of the rat.

This work is an ultrastructural study of the cells of the excretory duct epithelium of the submaxillary gland of the rat. This epithelium undergoes progressive loss of cytoplasm which leads to the presence of three distinct types of cell.

Induction of thyroid proliferative changes in rats treated with antithyroid compound.

This study was designed to investigate the histologic changes in goitrogen-induced thyroid growth of the rat. The animals were orally treated by 1% potassium perchlorate except the controls and were sacrificed in intervals ranging from 1 to 12 months. The thyroid weight increased progressively along the treatment and after 2 months showed a diffuse homogenous hypertrophy and hyperplasia of follicular cells, decreased amount of colloid and increased vascularity.

Adrenal myelolipoma simulating a retroperitoneal malignant neoplasm.

We describe a case of a large myelolipoma (15 by 12 cm. maximum diameter) that was removed surgically and resembled clinically and semeiologically a malignant retroperitoneal tumor. The patient also had chronic pancreatitis and cholelithiasis.

Progressive systemic sclerosis and nephrotic syndrome. An unusual association resulting in postpartum acute renal failure.

A 27-year-old, full-term pregnant woman with progressive systemic sclerosis (PSS) came to the hospital with marked proteinuria and edema. Two days later, she gave birth to a normal baby. After delivery and during the next 48 hours, renal failure developed.

[Symptomatic renal angiomyolipoma associated with tuberous sclerosis].

A kidney angiomyolipoma associated with tuberous sclerosis is described. This rare tumor is sometimes asymptomatic and is found at autopsy, but in some cases it may be confounded with a malignant tumor, as in the present case. The authors consider the angiomyolipoma as a choristoma rather than as a true neoplasm.

Oat cell carcinoma of the oesophagus. Case description and review of the literature.

The small oat cell type of carcinoma is only rarely seen in extrapulmonary sites. To date, nineteen cases have been described in the oesophagus, almost all by Japanese authors. In this report we review the relevant literature and add one more case of pure type to the total.

[Renal biopsy in the hemolytic-uremic syndrome in infancy. A study of three cases (author's transl)].

The hemolytic-uremic syndrome, although clearly described from the clinical and morphological points of view, has uncertain etilogy and pathogenesis for which various hypotheses have been advanced. In the immunohistochemical study of three recent infantile cases, whose clinical description and analysis follow those described in the literature, we found fibrinogen deposits, C3 and immunoglobulins in the walls and glomerular capillary vessels in two from which biopsies were taken early; while in the third case, in which the biopsy was taken a month after the process had begun, only fibrinogen was found. These findings suggest a pathogenesis of lesions involving an immunocomplex reaction with ulterior development of secondary intravascular coagulation.

Nonchromaffin paraganglioma of the duodenum.

A benign nonchromaffin paraganglioma of the duodenum is described and compared with other reported cases. Duodenal location is extremely rare but the morphology, based on the optical microscopic pattern (Zellballen) and the ultrastructural appearance is, comparable with paragangliomas of other sites. The lack of nerve fibres and ganglion cells in this tumour, together with the absence of a positive chromaffin reaction permits us to classify it as a pure nonchromaffin paraganglioma.