First-principles study of As interstitials in GaAs: Convergence, relaxation, and formation energy

Convergence of density-functional supercell calculations for defect formation energies, charge transition levels, localized defect state properties, and defect atomic structure and relaxation is investigated using the arsenic split interstitial in GaAs as an example. Supercells containing up to 217 atoms and a variety of {\bf k}-space sampling schemes are considered. It is shown that a good description of the localized defect state dispersion and charge state transition levels requires at least a 217-atom supercell, although the defect structure and atomic relaxations can be well converged in a 65-atom cell. Formation energies are calculated for the As split interstitial, Ga vacancy, and As antisite defects in GaAs, taking into account the dependence upon chemical potential and Fermi energy. It is found that equilibrium concentrations of As interstitials will be much lower than equilibrium concentrations of As antisites in As-rich, $n$-type or semi-insulating GaAs.Comment: 10 pages, 5 figure

Predictive clinico-pathological factors to identify BCG, unresponsive patients, after re-resection for T1 high grade non-muscle invasive bladder cancer

Introduction: Seventy-five percent of bladder cancers are non-muscle invasive. The treatment strategy includes the transurethral resection of bladder tumor (TURB) followed by intravesical immunotherapy with the bacillus of Calmette-Guerin (BCG) or chemotherapy, depending on the grade of bladder tumor. Despite a proper BCG intravesical instillations schedule, up to 40% of patients present a failure within 2 years. The aim of this retrospective study was to investigate the predictive factors in the response to BCG in patients with a high-grade non-muscle invasive bladder cancer diagnosis. Materials and methods: Patients with non-muscle invasive bladder cancer from 13 hospitals and academic institutions were identified and treated, from January 1, 2002, until December 31, 2012, with TURB and a subsequent re-TURB for restaging before receiving BCG. Follow-up was performed with urine cytology and cystoscopy every 3 months for 1 year and, successively every 6 months. Univariate and multivariate Cox regression models addressed the response to BCG therapy. Kaplan-Meier overall survival (OS) and cancer-specific survival (CSS) estimates were determined for BCG responsive vs. BCG unresponsive patients. Results: A total of 1,228 patients with non-muscle invasive bladder cancer were enrolled. Of 257 (20.9%) patients were BCG unresponsive. Independent predictive factors for response to BCG were: multifocality (HR: 1.4; 95% CI 1.05-1.86; P = 0.019), lymphovascular invasion (HR: 1.75; 95% CI 1.22-2.49; P = 0.002) and high-grade on re-TURB (HR: 1.39; 95% CI 1.02-1.91; P = 0.037). Overall survival was significantly reduced in BCG-unresponsive patients compared to BCG-responsive patients at 5 years (82.9% vs. 92.4%, P < 0.0001) and at 10 years (44.2% vs. 74.4%, P < 0.0001). Similarly, cancer-specific survival was reduced in BCG-unresponsive patients at 5 years (90.6% vs. 97.3%, P < 0.0001) and at 10 years (72.3% vs. 87.2%, P < 0.0001). Conclusion: Multifocality, lymphovascular invasion, and high-grade on re-TURB were independent predictors for response to BCG treatment. BCG-unresponsive patients reported worse oncological outcomes

Modified Glasgow Prognostic Score as a Predictor of Recurrence in Patients with High Grade Non-Muscle Invasive Bladder Cancer Undergoing Intravesical Bacillus Calmette–Guerin Immunotherapy

Background: A systemic inflammatory marker, the modified Glasgow prognostic score (mGPS), could predict outcomes in non-muscle-invasive bladder cancer (NIMBC). We aimed to investigate the predictive power of mGPS in oncological outcomes in HG/G3 T1 NMIBC patients undergoing Bacillus Calmette–Guérin (BCG) therapy. Methods: We retrospectively reviewed patient’s medical data from multicenter institutions. A total of 1382 patients with HG/G3 T1 NMIBC have been administered adjuvant intravesical BCG therapy, every week for 3 weeks given at 3, 6, 12, 18, 24, 30 and 36 months. The analysis of mGPS for recurrence and progression was performed using multivariable and univariable Cox regression models. Results: During follow-up, 659 patients (47.68%) suffered recurrence, 441 (31.91%) suffered progression, 156 (11.28%) died of all causes, and 67 (4.84%) died of bladder cancer. At multivariable analysis, neutrophil to lymphocyte ratio [hazard ratio (HR): 7.471; p = 0.0001] and erythrocyte sedimentation rate (ESR) (HR: 0.706; p = 0.006 were significantly associated with recurrence. mGPS has no statistical significance for progression (p = 0.076). Kaplan–Meier survival analysis showed a significant difference in survival among patients from different mGPS subgroups. Five-year OS was 93% (CI 95% 92–94), in patients with mGPS 0, 82.2% (CI 95% 78.9–85.5) in patients with mGPS 1 and 78.1% (CI 95% 60.4–70) in mGPS 2 patients. Five-year CSS was 98% (CI 95% 97–99) in patients with mGPS 0, 90% (CI 95% 87–94) in patients with mGPS 1, and 100% in mGPS 2 patients. Limitations are applicable to a retrospective study. Conclusions: mGPS may have the potential to predict recurrence in HG/G3 T1 NMIBC patients, but more prospective, with large cohorts, studies are needed to study the influence of systemic inflammatory markers in prediction of outcomes in NMIBC for a definitive conclusion

The Effect of Nanoparticles on Amyloid Aggregation Depends on the Protein Stability and Intrinsic Aggregation Rate

Nanoparticles interfere with protein amyloid formation. Catalysis of the process may occur due to increased local protein concentration and nucleation on the nanoparticle surface, whereas tight binding or a large particle/protein surface area may lead to inhibition of protein aggregation. Here we show a clear correlation between the intrinsic protein stability and the nanoparticle effect on the aggregation rate. The results were reached for a series of five mutants of single-chain monellin differing in intrinsic stability toward denaturation, for which a correlation between protein stability and aggregation propensity has been previously documented by Szczepankiewicz et al. [Mol. Biosyst 2010 7 (2), 521-532]. The aggregation process was monitored by thioflavin T fluorescence in the absence and presence of copolyrneric nanoparticles with different hydrophobic characters. For mutants with a high intrinsic stability and low intrinsic aggregation rate, we find that amyloid fibril formation is accelerated by nanoparticles. For find the opposite-a retardation of amyloid fibril formation by nanoparticles. Moreover, both catalytic and inhibitory effects are most pronounced with the least hydrophobic nanoparticles, which have a larger surface accessibility of hydrogen-bonding groups in the polymer backbone