Effect of hydration on conductivity of Ba4La x Ca2-X Nb2O11 + 0.5x (x = 0.5, 1, 1.5, 2) phases

Substitution of Ca by La in initial cubic double perovskite Ba 4(Ca2Nb2)O11[VO]1 allowed obtaining phases with a similar structure with a lower content of structural oxygen vacancies, Ba4(La x Ca2-x Nb 2)O11 + 0.5x [VO]1-0.5x (x = 0.5, 1, 1.5, 2). The impedance technique was used to measure the temperature dependences of conductivity in the atmosphere of dry and humid air. Transport numbers determined using the EMF method in an oxygen-air and water steam concentration cells point to the predominantly hole nature of conductivity in the high-temperature region (T > 600 C) and to predominance of proton conductivity in the low-temperature region. Activation energies of hole and proton conductivity were calculated. Thermogravimetric measurements were carried out under heating from 25 to 1000 C with simultaneous mass-spectrometric determination of evolved H2O and CO2. The properties of the studied Ba4(La x Ca2-x Nb 2)O11 + 0.5x (x = 0.5, 1, 1.5, 2) phases were compared with the earlier studied Ba4-x La x (Ca2Nb 2)O11 + 0.5x phases with similar lanthanum content. © 2013 Pleiades Publishing, Ltd

Role of Active Surveillance for Localized Small Renal Masses

Context: Stage migration of organ-confined renal masses is occurring as a result of incidental diagnosis, especially in the elderly. Active surveillance (AS) is gaining clinical traction as a treatment alternative to surgery and focal therapy. Objective: To assess contemporary data and evaluate AS risk trade-offs in the treatment of organ-confined kidney cancer. Evidence acquisition: A comprehensive search of the Embase, Medline and Cochrane databases was carried out. A systematic review of the role of AS for organ-confined renal masses was performed. A total of 28 studies were included in the systematic review. Evidence synthesis: The median linear tumor growth rate for clinically localized renal masses (CLRMs) was 0.37 cm/yr (interquartile range 0.15\u20130.7), with 0.22 cm/yr in the cT1a subgroup and 0.45 cm/yr in the cT1b\u2013\u20132 subgroup. The metastatic progression rate was 1\u20136% and was similar for cT1a (1\u20136%) and cT1b (0\u20135%); other-cause mortality for patients with CLRMs was 0\u201345% (1\u201325% for cT1a vs 11\u201313% for cT1b\u20132); cancer-specific mortality ranged between 0% and 18%. According to the 2011 Oxford scale, AS as a treatment option for CLRMs remains supported by level 3 evidence. Conclusions: Although no randomized clinical data are available, current data support oncologic safety for AS in the management of CLRMs, particularly for small renal masses and among elderly and/or comorbid patients. Patient summary: In this review we looked at the outcomes for patients with small kidney masses managed with surveillance. We found that surveillance is a safe initial option for tumors of less than 2 cm, especially in elderly and sick patients. Active surveillance for clinically localized renal masses is a safe initial option, especially for masses of <2 cm in elderly and sick patients. Further investigation to establish active surveillance protocols and follow-up are still missing. Prospective nonrandomized registry collection of data for patients with small renal masses is ongoing

Stereotactic ablative radiation therapy for renal cell carcinoma with inferior vena cava tumor thrombus

Background: Inferior vena cava tumor thrombus (IVC-TT) is a rare yet deadly sequel of renal cell carcinoma (RCC) with limited treatment options. The standard treatment is extirpative surgery, which has high rates of morbidity and mortality. As a result, many patients are unfit or unwilling to undergo surgery and face poor prognosis. This stresses the need for alternative options for local disease control. Our study aims to assess the feasibility and oncological outcomes of stereotactic ablative radiation (SAbR) for IVC-TT. Methods: A retrospective study reviewing six leading international institutions’ experience in treating RCC with IVC-TT with SAbR. Primary end point was overall survival using Kaplan-Meier. Results: Fifteen patients were included in the cohort. Over 50% of patients had high level IVC-TT (level III or IV), 66.7% had metastatic disease. Most eschewed surgery due to high surgical risk (7/15) or recurrent thrombus (3/15). All patients received SAbR to the IVC-TT with a median biologically equivalent dose (BED10) of 72 Gy (range: 37.5–100.8) delivered in a median of 5 fractions (range 1–5). Median overall survival was 34 months. Radiographic response was observed in 58% of patients. Symptom palliation was recorded in all patients receiving SAbR for this indication. Only grade 1 to 2 adverse events were noted. Conclusions: SAbR for IVC-TT appears feasible and safe. In patients who are not candidates for surgery, SAbR may palliate symptoms and improve outcomes. SAbR may be considered as part of a multimodal treatment approach for patients with RCC IVC-TT