Synthesis of monodispersed Ag-doped bioactive glass nanoparticles via surface modification

© 2016 by the authors.Monodispersed spherical Ag-doped bioactive glass nanoparticles (Ag-BGNs) were synthesized by a modified Stöber method combined with surface modification. The surface modification was carried out at 25, 60, and 80 °C, respectively, to investigate the influence of processing temperature on particle properties. Energy-dispersive X-ray spectroscopy (EDS) results indicated that higher temperatures facilitate the incorporation of Ag. Hydroxyapatite (HA) formation on Ag-BGNs was detected upon immersion of the particles in simulated body fluid for 7 days, which indicated that Ag-BGNs maintained high bioactivity after surface modification. The conducted antibacterial assay confirmed that Ag-BGNs had an antibacterial effect on E. coli. The above results thereby suggest that surface modification is an effective way to incorporate Ag into BGNs and that the modified BGNs can remain monodispersed as well as exhibit bioactivity and antibacterial capability for biomedical applications

Preliminary Human-in-the-Loop Assessment of Procedures for Very-Closely-Spaced Parallel Runways

Demand in the future air transportation system concept is expected to double or triple by 2025 [1]. Increasing airport arrival rates will help meet the growing demand that could be met with additional runways but the expansion airports is met with environmental challenges for the surrounding communities when using current standards and procedures. Therefore, changes to airport operations can improve airport capacity without adding runways. Building additional runways between current ones, or moving them closer, is a potential solution to meeting the increasing demand, as addressed by the Terminal Area Capacity Enhancing Concept (TACEC). TACEC requires robust technologies and procedures that need to be tested such that operations are not compromised under instrument meteorological conditions. The reduction of runway spacing for independent simultaneous operations dramatically exacerbates the criticality of wake vortex incursion and the calculation of a safe and proper breakout maneuver. The study presented here developed guidelines for such operations by performing a real-time, human-in-the-loop simulation using precision navigation, autopilot-flown approaches, with the pilot monitoring aircraft spacing and the wake vortex safe zone during the approach

The possible effect of a sanitization program on intraspecies differentiation of Listeria monocytogenes strains isolated from a fish processing plant

Forty-seven Listeria monocytogenes strains isolated during a year in a selected Polish fish-processing plant as well as 7 L. monocytogenes strains of different origins (including a reference strain) were analyzed in our studies. Strains were isolated from raw fish fillets (flounder), frozen coated flounder fillets, coating ingredients, and the processing environment. Isolation of strains covered the period of a sanitization program introduced in the plant. L. monocytogenes was identified using conventional microbiological methods and the PCR technique. RAPD (random amplified polymorphic DNA) technique for fingerprinting was applied to analyze the intraspecies diversity. Six RAPD types (A \u2013 F) and seven unique strains were revealed as a result of fingerprinting with one persistent type isolated from July 1999 to February 2000. It was detected for the first time after one month of sanitization. Its occurrence could have been promoted by clone selection either due to ineffective disinfection or to resistance against the disinfectant. As L. monocytogenes mostly occurred on frozen products, this indicates that contamination could start during product freezing, cold storage, or handling. The results revealed that there is a crucial need for preparing sanitization schemes precisely targeted at L. monocytogenes to avoid its recurrence as persistent \u2018in \u2013 house' strains. The possibility of incorrect interpretations of classical microbiological test results as well as the necessity to introduce assays based on nucleic acid analysis into epidemiological investigations were emphasized

Polyurethane composites with different matrices filled with glass microspheres

Przedmiotem pracy są kompozyty poliuretanowe z dwóch różnych typów poliuretanów napełnianych mikrosferami szklanymi przeznaczone do wytwarzania form stosowanych w technologii odlewania próżniowego (VC). Oceniano wpływ napełniacza na właściwości wytworzonych kompozytów. Wyznaczono lepkość przedmieszek, a usieciowane kompozyty scharakteryzowano metodami analizy termomechanicznej (DMA) oraz analizy struktury z zastosowaniem spektroskopii w podczerwieni (FT-IR) i skaningowej mikroskopii elektronowej (SEM). Przedstawiono również wyniki badań wytrzymałościowych.The paper concerns composites made of polyurethane materials intended for the production of molds used in the vacuum casting process (VC). Two types of polyurethanes were applied to prepare the composites filled with glass microspheres. The influence of the filler on the properties of the resulting polyurethane composites was investigated. The viscosity of the premixes for the preparation of these composites was determined. The crosslinked composites were characterized using thermomechanical analysis (DMA), while their structure was investigated by infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The results of strength tests are also presented

Polyurethane composites with different matrices filled with glass microspheres

Przedmiotem pracy są kompozyty poliuretanowe z dwóch różnych typów poliuretanów napełnianych mikrosferami szklanymi przeznaczone do wytwarzania form stosowanych w technologii odlewania próżniowego (VC). Oceniano wpływ napełniacza na właściwości wytworzonych kompozytów. Wyznaczono lepkość przedmieszek, a usieciowane kompozyty scharakteryzowano metodami analizy termomechanicznej (DMA) oraz analizy struktury z zastosowaniem spektroskopii w podczerwieni (FT-IR) i skaningowej mikroskopii elektronowej (SEM). Przedstawiono również wyniki badań wytrzymałościowych.The paper concerns composites made of polyurethane materials intended for the production of molds used in the vacuum casting process (VC). Two types of polyurethanes were applied to prepare the composites filled with glass microspheres. The influence of the filler on the properties of the resulting polyurethane composites was investigated. The viscosity of the premixes for the preparation of these composites was determined. The crosslinked composites were characterized using thermomechanical analysis (DMA), while their structure was investigated by infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The results of strength tests are also presented