Uralyt-K

High-Temperature Hydrogen Permeability Tests of Ta Tubes.

Capobianco Damiano D, Zanlucchi Silvia S, Beone Teresa T, Bartolucci Lorenzo L et al.

Refractory metals are being studied as alternatives to Pd and its alloys for the separation of hydrogen in high-temperature processes. The development of a membrane reactor for the production of hydrogen via water splitting has required studying hydrogen permeability through Ta at temperatures above 1273 K, for which no data is available in the literature. A dedicated experimental setup has been realized for testing Ta tubes in the temperature range 673-1573 K. Despite the use of controlled atmospheres and ultra-pure gases (with oxygen content below a few ppm), the tests over 1473 K have involved the formation of oxide layers over the metal surfaces, as verified by SEM-EDS analyses. The presence of oxide layers significantly increases the energy barrier to permeation: in agreement with a modest surface oxidation, at lower temperatures (673-1273 K) the activation energy of 2679.8 K has been measured against the value of 30,691 K measured in the high-temperature tests (1473-1573 K).

An unusual case of severe acquired coagulopathy from cancer cachexia-related vitamin K deficiency.

Balusu Kavya K, Foo Cher Ying CY, Kouides Peter P

Vitamin K deficiency is a well recognized cause of acquired coagulopathy, but its presentation as severe coagulopathy in the setting of advanced malignancy is not well described. We report a 67-year-old man with recurrent metastatic urothelial carcinoma and severe cachexia who presented with a markedly prolonged prothrombin time (PT) of 105.8 s and activated partial thromboplastin time (APTT) of 58.2 s. Hematologic evaluation revealed deficiencies in vitamin K-dependent clotting factors, and his coagulopathy corrected with intravenous vitamin K replacement. This case highlights that cancer cachexia itself can precipitate clinically significant vitamin K deficiency in patients with advanced malignancy leading to severe coagulopathy.

Nickel K-Edge XANES Studies on Pyridinophane-Supported Coordination Complexes.

Westawker Luke P LP, Wallick Rachel F RF, Schultz Jason W JW, Burke John H JH et al.

X-ray absorption spectroscopy (XAS) is a powerful technique to identify the electronic and geometric structures surrounding a specific element and is of growing interest for the characterization of homogeneous organometallic compounds, especially for sensitive and highly reactive in situ species. In this study, we performed a systematic, quantitative analysis of the rising Ni K-edge for a series of 25 pyridinophane-supported compounds by fitting the K-edge to the relevant 1s to 4p transitions. We observe how ligand substitution, the oxidation state, and variable binding modes have a direct effect on the energy and shape of the Ni K-edge as they affect Ni bond distances and p-orbital symmetry. By leveraging the flexible denticity of pyridinophane ligands, we quantify the variable solution-phase binding mode of previously ambiguous structures. This study also helps establish using the intense, rising Ni K-edge to monitor in situ reactivity and to characterize coordination environments of Ni catalysts using only 1-2 scans, without relying on the EXAFS region.

Reply to Sridharan K et al.

Altintas Mese Ceren C, Mese Ismail I, Akinci D'Antonoli Tugba T