Effect of nitrogen on the antibacterial behavior of oxynitride glasses

The main drawback of bioglasses is their restricted use in load bearing applications and the consequent need to develop stronger glassy materials. This has led to the consideration of oxynitride glasses for numerous biomedical applications. This paper investigated two different types of glasses at a constant cationic ratio, with and without nitrogen (a N containing and a N-free glass composition) to better understand the effect of N on the biological properties of glasses. The results revealed that the addition of N increased the glass transition temperature, isoelectric point (IEP) and slightly increased wettability. Moreover, compared to N including glass, N-free glass exhibited better anti-bacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), two key bacteria that infect implants. In summary, these in vitro results indicated that amine functional groups existing in N containing glasses which are missing in N-free glasses, caused a slight difference in wetting behavior and a more obvious change in isoelectric point and in bacterial response. N-free glasses exhibited better inhibitory results both against E. coli and S. aureus compared to N including glass suggesting that oxygen rich glasses should be further studied for their novel antibacterial properties.     

Design and Characterization of a New pVII Combinatorial Phage Display Peptide Library for Protease Substrate Mining Using Factor VII Activating Protease (FSAP) as Model

We describe a novel, easy and efficient combinatorial phage display peptide substrate-mining method to map the substrate specificity of proteases. The peptide library is displayed on the pVII capsid of the M13 bacteriophage, which renders pIII necessary for infectivity and efficient retrieval, in an unmodified state. As capture module, the 3XFLAG was chosen due to its very high binding efficiency to anti-FLAG mAbs and its independency of any post-translational modification. This library was tested with Factor-VII activating protease (WT-FSAP) and its single-nucleotide polymorphism variant Marburg-I (MI)-FSAP. The WT-FSAP results confirmed the previously reported Arg/Lys centered FSAP cleavage site consensus as dominant, as well as reinforcing MI-FSAP as a loss-of-function mutant. Surprisingly, rare substrate clones devoid of basic amino acids were also identified. Indeed one of these peptides was cleaved as free peptide, thus suggesting a broader range of WT-FSAP substrates than previously anticipated.     

Zinc Oxide Nanowire Decorated Single‐Use Electrodes for Electrochemical DNA Detection

The surfaces of pencil graphite electrodes (PGEs) were decorated with zinc oxide nanowires (ZnO NWs) for the electrochemical detection of nucleic acids. ZnO NWs were synthesized through simple hydrothermal method. PGEs decorated with ZnO NWs (ZnO NW/PGEs) were electrochemically characterized through cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) following morphological characterization through transmission (TEM) and scanning electron microscopy (SEM). Enhanced sensor response obtained using ZnO NW/PGEs contrary to the bare PGE (control) samples. Our preliminary results simply reveal the potential of combining ZnO NWs with disposable sensor technology for the electrochemical detection of DNA.     

Textile supercapacitors‐based on MnO2/SWNT/conducting polymer ternary composites

This paper describes a simple and fast process for the fabrication of flexible and textile‐based supercapacitors. Symmetric electrodes made up of binder‐free ternary composites of manganese oxide (MnO₂) nanoparticles, single walled carbon nanotubes (SWNT) and a conducting polymer (either polyaniline (PANI) or poly(3,4‐ethylenedioxythiophene)–poly(styrenesulfonate) (PEDOT:PSS)) were layer‐by‐layer deposited onto cotton substrates by dip coating method. Solid‐state supercapacitor devices were assembled using a gel electrolyte. Specific capacitances of 294 F/g and 246 F/g were obtained for MnO₂/SWNT/PANI and MnO₂/SWNT/PEDOT:PSS ternary nanocomposite supercapacitors, respectively. Power densities for these supercapacitors were 746.5 W/kg and 640.5 W/kg for MnO₂/SWNT/PANI and MnO₂/SWNT/PEDOT:PSS, respectively. Good capacity retention (more than 70%) upon cycling over 1000 times was achieved for both electrode compositions. Supercapacitors demonstrated in this work would be well suited as disposable power sources for wearable and intelligent textiles. Copyright © 2015 John Wiley & Sons, Ltd.     

Estimation of target station data using satellite data and deep learning algorithms

In this study, an innovative model has been developed for wind speed estimation through the Deep Learning method using hourly wind speed data from the measurement stations of the General Directorate of Meteorology in Van and Hakkari provinces in Turkey in conjunction with simultaneous satellite images from Eumetsat. Obtained satellite images were used during the introduction of the model, while wind speed data were used at the output stage. As a result of the findings, it was found that 85% accuracy performance could be achieved to provide sufficient insight for systems that are widely established worldwide. The model, developed as a result of the study, eliminates the need to install wind measuring stations for any region on earth within the satellite field in terms of determining wind potential. Since the field of view of the Meteosat 7 satellite covers the whole of Eastern Europe, it was determined that it could predict a high rate of up to 6 hours later by the method used in image analysis. The systems to be controlled with this method will be able to examine the weather events instantly at each point in the satellite field of view and make more accurate decisions. Also, companies will be able to perform a more detailed and rapid field scan compared to existing limited methods, and reduce initial investment costs and operating costs in terms of renewable energy resources investments.     

Modelling the impact of land-cover change on potential soil loss in the Taita Hills,Kenya, between 1987 and 2003 using remote-sensing and geospatial data

In sub-Saharan Africa, natural vegetation is being transformed into agricultural lands at a fast rate, endangering ecosystem services and increasing soil-loss potential, which may trigger land degradation. For the Taita Hills study area in Kenya, multi-temporal land-cover models of 1987, 1999 and 2003, derived from Satellite Pour l'Observation de la Terre (SPOT) imagery using a multi-scale segmentation/object relationship modelling (MSS/ORM) methodology and a rainfall layer, a digital elevation model (DEM) and a digital soil map were applied to model potential soil loss. Population growth in the area has led to a shortage of agricultural land and movement of people to the lowlands, evidenced by a 39% (9.3 km²) increase in croplands from 30% to 41% of the study area during the research time frame. Expansion took place mostly in surrounding foothills and lowlands, at the expense of natural shrubland and grassland, but also occurred in the hills. Universal soil-loss equation (USLE) model results showed a 60% (4 km²) increase in the area of very high potential soil loss, from 7% of the study area in 1987 to 12% in 2003, due mainly to very high soil-loss potential in croplands. Whilst the area of croplands as a whole increased, the relative proportion of very high soil-loss potential in croplands remained 20%, both in 1987 and in 2003, indicating that newly cleared agricultural lands with vulnerable soils are the most at-risk areas.     

Comparison on efficiency factors of F and C types of fly ashes

Fly ashes are obtained from thermal power plants and they are pozzolanic materials, which can act as partial replacement material for both portland cement and fine aggregate. With their economical advantages and potential for improving fresh and hardened concrete performance, they have some benefits for using in concrete industry. In this study, the objective was to find the efficiency factors of Turkish C and F-type fly ashes and to compare their properties. Three different cement dosages were used (260, 320, 400 kg/m³), two different ratios (10% and 17%) of cement reduced from the control concretes and three different ratios (depending on cement reduction ratio) of fly ash were added into the mixtures. At the ages of 28 and 90 days, compressive strength, modulus of elasticity and ultrasound velocity tests were carried out. From the compressive strength results, the k efficiency factors of C and F-type fly ashes were obtained. As a result, it is seen that efficiency factors of the concrete produced by the replacement of F and C type fly ashes with cement increase with the increase in cement dosage and concrete age.     

The mechanism of the sudden termination of carbon nanotube supergrowth

The effect of growth conditions and catalyst lifetime on the supergrowth of carbon nanotubes (CNTs) through a water assisted chemical vapor deposition has been investigated. The reasons behind the observed sudden termination of the CNT growth were explored. A proper amount of water was found to improve the activity of the catalyst and enhance the growth rate of CNTs. However, the introduction of water did not extend the catalyst lifetime leading to unavoidable termination of the CNT growth. Further experiments demonstrated that in addition to catalyzing the CNT growth, catalyst particles can also decompose/etch the C sp2/sp3 bonds including those in the CNTs. The existing termination mechanism for the CNT growth fails to explain this. We therefore propose a model based on the catalyst phase transformation using the Johnson–Mehl–Avrami–Kolmogorov theory to predict the growth rate and termination of the CNT growth.     

Large deformation of thermally bonded random fibrous networks: microstructural changes and damage

A mechanical behaviour of random fibrous networks is predominantly governed by their microstructure. This study examines the effect of microstructure on macroscopic deformation and failure behaviour of random fibrous networks and its practical implication for optimisation of its structure by using finite-element simulations. A subroutine-based parametric modelling approach—a tool to develop and characterise random fibrous networks—is also presented. Here, a thermally bonded polypropylene nonwoven fabric is used as a model system. Its microstructure is incorporated into the model by explicit introduction of fibres according to their orientation distribution in the fabric. The model accounts for main deformation and damage mechanisms experimentally observed and provides the meso- and macro-level responses of the fabric. The suggested microstructure-based approach identifies and quantifies the spread of stresses and strains in fibres of the network as well as its structural evolution during deformation and damage. Its simulations also predict a continuous shift in the distribution of stresses due to structural evolution and progressive failure of fibres.