Highly translucent nanostructured glass-ceramic

Transparent and translucent glass-ceramics (GCs) are found in an increasing number of domestic and high-technology applications. In this paper, we evaluated and optimized the effects of two-stage heat treatments on the resulting crystalline phases and microstructure of a glass of the SiO₂–Li₂O–P₂O₅–TiO₂–CaO–ZnO–Al₂O₃ system. The objective was to develop a transparent nanostructured glass-ceramic (GC). After numerous heat treatment trials, we found that a long nucleation period of 72 h at 455 °C followed by a crystal growth treatment at 660 °C for 2 h resulted in a highly translucent GC having homogenously distributed nanocrystals. The relatively high amount of P₂O₅ (2.5 mol%) induced the formation of lithium disilicate as the main crystal phase. We thus developed a GC having crystals under 50 nm, with a high crystallized fraction (52%vol. Li₂Si₂O₅ and 26% vol Li₂SiO₃), transmittance of approximately 80% in the visible spectrum for 1.2 mm thick specimens, nano hardness of 8.7 ± 0.1 GPa (load of 400 mN), a high elastic modulus of 138 ± 3 GPa as measured by nanoindentation, and good flexural strength (350 ± 40 MPa) as measured by ball-on-3 balls tests. Due to its high content of Li⁺, this GC has the potential to be chemically strengthened and can be further developed to be used in a number of applications, such as on displays of electronic devices.     

miR-16-5p Is a Stably-Expressed Housekeeping MicroRNA in Breast Cancer Tissues from Primary Tumors and from Metastatic Sites

For quantitative microRNA analyses in formalin-fixed paraffin-embedded (FFPE) tissue, expression levels have to be normalized to endogenous controls. To investigate the most stably-expressed microRNAs in breast cancer and its surrounding tissue, we used tumor samples from primary tumors and from metastatic sites. MiRNA profiling using TaqMan^® Array Human MicroRNA Cards, enabling quantification of 754 unique human miRNAs, was performed in FFPE specimens from 58 patients with metastatic breast cancer. Forty-two (72%) samples were collected from primary tumors and 16 (28%) from metastases. In a cross-platform analysis of a validation cohort of 32 FFPE samples from patients with early breast cancer genome-wide microRNA expression analysis using SurePrintG3 miRNA (8 × 60 K)^® microarrays from Agilent^® was performed. Eleven microRNAs could be detected in all samples analyzed. Based on NormFinder and geNorm stability values and the high correlation (rho ≥ 0.8) with the median of all measured microRNAs, miR-16-5p, miR-29a-3p, miR-126-3p, and miR-222-3p are suitable single gene housekeeper candidates. In the cross-platform validation, 29 human microRNAs were strongly expressed (mean log2-intensity > 10) and 21 of these microRNAs including miR-16-5p and miR-29a-3p were also stably expressed (CV < 5%). Thus, miR-16-5p and miR-29a-3p are both strong housekeeper candidates. Their Normfinder stability values calculated across the primary tumor and metastases subgroup indicate that miR-29a-3p can be considered as the strongest housekeeper in a cohort with mainly samples from primary tumors, whereas miR-16-5p might perform better in a metastatic sample enriched cohort.     

Production of Methyl Oleate in Reactive‐Separation Systems

The esterification of oleic acid and methanol using sulfuric acid as a homogeneous catalyst is studied in reactive‐separation systems. The conversion of the free fatty acid was investigated in two different experiments with the molar ratio of methanol/oleic acid, amount of catalyst, temperature, and reaction time as variables. The conversion of the free fatty acid was found to depend strongly on the molar ratio of methanol/oleic acid. The reaction time had a direct effect on the conversion of the free fatty acid, and this conversion decreased with higher temperature. These results were valuable for a preliminary study on biodiesel production, using an acid homogeneous catalyst in a reactive dividing‐wall distillation column.     

The preparation of α‐bis and α,ω‐tetrakis aromatic oxazolyl‐ and carboxyl‐functionalized polymers using 1,1‐bis[4‐(2‐(4,4‐dimethyl‐1,3‐oxazolyl))phenyl]ethylene in atom transfer radical polymerization reactions

The preparation of new compounds, 1,1‐bis[4‐(2‐(4,4‐dimethyl‐1,3‐oxazolyl))phenyl]ethanol and a new symmetrically disubstituted 1,1‐diphenylethylene derivative, 1,1‐bis[4‐(2‐(4,4‐dimethyl‐1,3‐oxazolyl))phenyl]ethylene, is described. 1,1‐Bis[4‐(2‐(4,4‐dimethyl‐1,3‐oxazolyl))phenyl]ethylene was utilized as a dioxazolyl initiator precursor for the polymerization of styrene by atom transfer radical polymerization (ATRP) methods to produce α‐bis(oxazolyl) polystyrene. The kinetic study of the polymerization process indicated that the free radical polymerization reaction for the preparation of α‐bis(oxazolyl) polystyrene follows first‐order rate kinetics with respect to monomer consumption. α,ω‐Tetrakis(oxazolyl) polystyrene was prepared by a new, in situ, controlled/living, post‐ATRP chain‐end‐functionalization reaction which involves the direct addition of 1,1‐bis[4‐(2‐(4,4‐dimethyl‐1,3‐oxazolyl))phenyl]ethylene to the ω‐terminus of the α‐bis(oxazolyl) polystyrene derivative, without the isolation and purification of the polymeric precursor. α‐Bis(carboxyl) and α,ω‐tetrakis(carboxyl) polystyrene derivatives were obtained by the quantitative chemical transformation of the oxazoline groups of the respective aromatic oxazolyl chain‐end‐functionalized polystyrene derivatives to the aromatic carboxyl groups. The organic precursor compounds, the dioxazolyl‐functionalized 1,1‐diphenylethylene derivative and the functionalized polymers were characterized using ¹H NMR and ¹³C NMR spectrometry and Fourier transform infrared spectroscopy, size‐exclusion and thin‐layer chromatography and non‐aqueous titration measurements. © 2014 Society of Chemical Industry     

Proactive defragmentation in elastic optical networks under dynamic load conditions

The main weakness of elastic optical networks (EON), under dynamic traffic conditions, stems from spectrum fragmentation. A lot of research efforts have been dedicated during recent years to spectrum defragmentation. In this work, a thorough study about proactive defragmentation is carried out. Effects of the different defragmentation parameters on the EON performance are analyzed, and appropriate values of the defragmentation period, which guarantee suitable network performance while keeping the network control complexity at reasonable values, are obtained by means of extensive simulations. Benefit obtained by applying different defragmentation strategies, in terms of increase in the supported load at a given bandwidth blocking probability, is also reported. Different traffic conditions and network topologies are simulated to assess the validity of the obtained results.     

The Manifesto Off the Shelf: Educating Black Architects at Morgan State University

This study will look at the education of black architects in the undergraduate Architecture and Environmental Design Program (BSAED) at Morgan State University (MSU) relative to the vision of its founding director, Melvin Mitchell. Though retiring shortly after the start of the program in 2001, Mitchell left on the shelf his book The Crisis of the African-American Architect, which included a manifesto for educating black architects for the 21st century. Examining Mitchell's book provides for an evaluation of the current program and pedagogy, relative to Mitchell's vision of the future of black architecture and black architects.