Interaction of molecular nitrogen with vanadium oxide in the absence and presence of water vapor at room temperature: Near-ambient pressure XPS.

Interactions of N2 at oxide surfaces are important for understanding electrocatalytic nitrogen reduction reaction (NRR) mechanisms. Interactions of N2 at the polycrystalline vanadium oxide/vapor interface were monitored at room temperature and total pressures up to 10-1 Torr using Near-Ambient Pressure X-ray Photoelectron Spectroscopy (NAP-XPS). The oxide film was predominantly V(IV), with V(III) and V(V) components. XPS spectra were acquired in environments of both pure N2 and equal pressures of N2 and H2O vapor. In pure N2, broad, partially resolved N1s features were observed at binding energies of 401.0 and 398.7 eV, with a relative intensity of ∼3:1, respectively. These features remained upon subsequent pumpdown to 10-9 Torr. The observed maximum N surface coverage was ∼1.5 × 1013 cm-2-a fraction of a monolayer. In the presence of equal pressures of H2O, the adsorbed N intensity at 10-1 Torr is ∼25% of that observed in the absence of H2O. The formation of molecularly adsorbed H2O was also observed. Density functional theory-based calculations suggest favorable absorption energies for N2 bonding to both V(IV) and V(III) cation sites but less so for V(V) sites. Hartree-Fock-based cluster calculations for N2-V end-on adsorption show that experimental XPS doublet features are consistent with the calculated shake-up and normal, final ionic configurations for N2 end-on bonding to V(III) sites but not V(IV) sites. The XPS spectra of vanadium oxide transferred in situ between electrochemical and UHV environments indicate that the oxide surfaces studied here are stable upon exposure to the electrolyte under NRR-relevant conditions.

Granulocytic sarcoma presenting as a diffuse renal mass before hematological manifestations of acute myelogenous leukemia.

Granulocytic sarcoma is a rare tumor composed of granulocytic precursor cells. The most common sites of involvement include the bones, soft tissue, lymph nodes and skin. Granulocytic sarcoma usually develops as a delayed manifestation of the disease process in patients with known acute myelogenous leukemia. To our knowledge we report the first case of renal granulocytic sarcoma presenting as the first sign of acute myelogenous leukemia. Computerized tomography and magnetic resonance imaging revealed diffuse nonspecific global tumor infiltration of the kidney and ureter. Renal granulocytic sarcoma was diagnosed on open renal biopsy and acute myelogenous leukemia on bone marrow biopsy. There has been partial response to combination chemotherapy. Renal granulocytic sarcoma may diffusely involve the kidney as the only manifestation of acute myelogenous leukemia and it should be included in the differential diagnosis of the many disease entities with global renal involvement since initial treatment is combination chemotherapy.