Deciphering the Interaction of Single-Phase La0.3Sr0.7Fe0.7Cr0.3O3-δ with CO2/CO Environments for Application in Reversible Solid Oxide Cells.

A detailed study aimed at understanding and confirming the reported highly promising performance of a La0.3Sr0.7Fe0.7Cr0.3O3-δ (LSFCr) perovskite catalyst in CO2/CO mixtures, for use in reversible solid oxide fuel cells (RSOFCs), is reported in this work, with an emphasis on chemical and performance stability. This work includes an X-ray diffraction (XRD), thermogravimetric analysis (TGA), and electrochemical study in a range of pO2 atmospheres (pure CO2, CO alone (balance N2), and a 90-70% CO2/10-30% CO containing mixture), related to the different conditions that could be encountered during CO2 reduction at the cathode. Powdered LSFCr remains structurally stable in 20-100% CO2 (balance N2, pO2 = 10-11-10-12 atm) without any decomposition. However, in 30% CO (balance N2, pO2 ∼ 10-26 atm), a Ruddlesden-Popper phase, Fe nanoparticles, and potentially some coke are observed to form at 800 °C. However, this can be reversed and the original perovskite can be recovered by heat treatment in air at 800 °C. While no evidence for coke formation is obtained in 90-70% CO2/10-30% CO (pO2 = 10-17-10-18 atm) mixtures at 800 °C, in 70 CO2/30 CO, minor impurities of SrCO3 and Fe nanoparticles were observed, with the latter potentially beneficial to the electrochemical activity of the perovskite. Consistent with prior work, symmetrical two-electrode full cells (LSFCr used at both electrodes), fed with the various CO2/CO gas mixtures at one electrode and air at the other, showed excellent electrochemical performance at 800 °C, both in the SOFC and in SOEC modes. Also, LSFCr exhibits excellent stability during CO2 electrolysis in medium-term potentiostatic tests in all gas mixtures, indicative of its excellent promise as an electrode material for use in symmetrical solid oxide cells.

Primitive neuroectodermal tumor of kidney with Level III inferior vena cava thrombus.

Primitive neuroectodermal tumor (PNET) of the kidney is an extremely rare renal neoplasm with only about 50 reported cases in the literature. These tumors behave aggressively and carry a poor prognosis. A 22 years female patient presented with right lumber and right hypochondrium lump of 4 months duration. Commutated tomography revealed large right renal mass with renal vein and inferior vena cava (IVC) thrombus. Magnetic resonance imaging abdomen demonstrated the extension of tumor thrombus up to the junction of hepatic vein and IVC. Preoperative percutaneous needle biopsy was performed. Histopathology demonstrated small round to oval cells with scanty cytoplasm and cells are arranged in clusters. Immunohistochemical staining demonstrated a highly specific cluster of differentiation 99, confirming the diagnosis of a PNET.

Spontaneous Rippling and Subsequent Polymer Molding on Yttria-Stabilized Zirconia (110) Surfaces.

Spontaneous nanoripple formation on (110) surfaces of yttria-stabilized zirconia, YSZ-(110), is achieved by diffusional surface doping with rare-earth oxides. Periodic arrays of parallel nanobars separated by channels (period ∼100 nm) grow out of the dopant sources, covering relatively wide areas of the surface (∼10 µm). The nanobars mound up on the surface by diffusion, exhibiting morphological uniformity and alignment, with their long axis lying parallel to the [11̅0] direction in the YSZ-(110) surface. The process for forming these nanobar arrays can be as simple as sprinkling of rare-earth oxide powder (dopant source) on YSZ-(110) surface and annealing in a high temperature air furnace. However, higher control on dopant dispersion on the surface is demonstrated with other techniques, including photolithography and inkjet printing. The ripple arrays extend anisotropically on the (110) surface, obeying the parabolic growth law, and showing principal values of the rate constant along [11̅0] (maximum) and [001] (minimum), as expected from the symmetry of the (110) surface. The self-patterned ceramic substrates are well-suited for pattern transfer by replica molding, as illustrated by single-step molding with polydimethylsiloxane (PDMS), which is a widely used biomaterial in cell-culture studies.

Study of predictive factors affecting the prolonged urinary leakage after percutaneous nephrolithotomy.

OBJECTIVE: To evaluate the factors that may influence the prolonged urinary leakage following percutaneous nephrolithotomy (PCNL). MATERIALS AND METHODS: A total of 936 consecutive patients underwent PCNL during the study period from April 2013 to December 2014 at our center, and data were recorded prospectively. Patients who required stage PCNL, chronic renal failure and diabetic patients, concurrent ureteric stone and patients in whom double-J stent was placed because of ureteropelvic injury, or pelvicalyceal extravasation were excluded from the study. After exclusion, 576 patients were included in the study. The predictive factors that may lead to prolonged urinary leakage after PCNL were broadly categorized into patient-related factors and procedure-related factors. Patients were divided into two groups: Group 1 (n = 32) - Required double-J stent placement due to prolonged urinary leakage (>48 h) after removal of the nephrostomy tube. Group 2 (n = 544) - Did not require double-J stent placement. RESULTS: Patient-related factors such as stone complexity, grade of hydronephrosis, renal parenchymal thickness in access line, and intra-parenchymal renal pelvis were most important factors for prolonged urinary leakage (P < 0.05, P < 0.05, P < 0.05, and P < 0.05, respectively), while procedure-related factors such as multiple punctures, surgeon's experience, and residual stones were most important factors for prolonged urinary leakage (P < 0.05, P < 0.05, and P < 0.05, respectively). CONCLUSION: In the present study, several factors appear to affect post-PCNL prolonged urinary leakage. We suggest that patients who are at increased risk of prolonged urinary leakage double-J stent should be placed at the end of PCNL procedure.

Self assembly of nanoislands on YSZ-(001) surface: a mechanistic approach toward a robust process.

We experimentally investigate the mechanism of formation of self-assembled arrays of nanoislands surrounding dopant sources on the (001) surface of yttria-stabilized zirconia. Initially, we used lithographically defined thin-film patches of gadolinia-doped ceria (GDC) as dopant sources. During annealing at approximately one-half the melting temperature of zirconia, surface diffusion of dopants leads to the breakup of the surface around the source, creating arrays of epitaxial nanoislands with a characteristic size (~100 nm) and alignment along elastically compliant directions, <110>. The breakup relieves elastic strain energy at the expense of increasing surface energy. On the basis of understanding the mechanism of island formation, we introduce a simple and versatile powder-based doping process for spontaneous surface patterning. The new process bypasses lithography and conventional vapor-source doping, opening the door to spontaneous surface patterning of functional ceramics and other refractory materials. In addition to using GDC solid-solution powders, we demonstrate the effectiveness of the process in another system based on Eu2O3.