Supramolecular peptide nanofiber morphology affects mechanotransduction of stem cells

Chirality and morphology are essential factors for protein function and interactions with other biomacromolecules. Extracellular matrix (ECM) proteins are also similar to other proteins in this sense; however, the complexity of the natural ECM makes it difficult to study these factors at the cellular level. The synthetic peptide nanomaterials harbor great promise in mimicking specific ECM molecules as model systems. In this work, we demonstrate that mechanosensory responses of stem cells are directly regulated by the chirality and morphology of ECM-mimetic peptide nanofibers with strictly controlled characteristics. Structural signals presented on l-amino acid containing cylindrical nanofibers (l-VV) favored the formation of integrin β1-based focal adhesion complexes, which increased the osteogenic potential of stem cells through the activation of nuclear YAP. On the other hand, twisted ribbon-like nanofibers (l-FF and d-FF) guided the cells into round shapes and decreased the formation of focal adhesion complexes, which resulted in the confinement of YAP proteins in the cytosol and a corresponding decrease in osteogenic potential. Interestingly, the d-form of twisted-ribbon like nanofibers (d-FF) increased the chondrogenic potential of stem cells more than their l-form (l-FF). Our results provide new insights into the importance and relevance of morphology and chirality of nanomaterials in their interactions with cells and reveal that precise control over the chemical and physical properties of nanostructures can affect stem cell fate even without the incorporation of specific epitopes

Optical gain in 1.3-μm electrically driven dilute nitride VCSOAs

We report the observation of room-temperature optical gain at 1.3 μm in electrically driven dilute nitride vertical cavity semiconductor optical amplifiers. The gain is calculated with respect to injected power for samples with and without a confinement aperture. At lower injected powers, a gain of almost 10 dB is observed in both samples. At injection powers over 5 nW, the gain is observed to decrease. For nearly all investigated power levels, the sample with confinement aperture gives slightly higher gain

Reliability and accuracy of single-molecule FRET studies for characterization of structural dynamics and distances in proteins

Single-molecule Förster-resonance energy transfer (smFRET) experiments allow the study of biomolecular structure and dynamics in vitro and in vivo. We performed an international blind study involving 19 laboratories to assess the uncertainty of FRET experiments for proteins with respect to the measured FRET efficiency histograms, determination of distances, and the detection and quantification of structural dynamics. Using two protein systems with distinct conformational changes and dynamics, we obtained an uncertainty of the FRET efficiency ≤0.06, corresponding to an interdye distance precision of ≤2 Å and accuracy of ≤5 Å. We further discuss the limits for detecting fluctuations in this distance range and how to identify dye perturbations. Our work demonstrates the ability of smFRET experiments to simultaneously measure distances and avoid the averaging of conformational dynamics for realistic protein systems, highlighting its importance in the expanding toolbox of integrative structural biology

Reliability and accuracy of single-molecule FRET studies for characterization of structural dynamics and distances in proteins

Single-molecule Förster-resonance energy transfer (smFRET) experiments allow the study of biomolecular structure and dynamics in vitro and in vivo. We performed an international blind study involving 19 laboratories to assess the uncertainty of FRET experiments for proteins with respect to the measured FRET efficiency histograms, determination of distances, and the detection and quantification of structural dynamics. Using two protein systems with distinct conformational changes and dynamics, we obtained an uncertainty of the FRET efficiency ≤0.06, corresponding to an interdye distance precision of ≤2 Å and accuracy of ≤5 Å. We further discuss the limits for detecting fluctuations in this distance range and how to identify dye perturbations. Our work demonstrates the ability of smFRET experiments to simultaneously measure distances and avoid the averaging of conformational dynamics for realistic protein systems, highlighting its importance in the expanding toolbox of integrative structural biology

Quantitative porosity classification using image analysis and its application in estimating petrophysical properties of sandstone reservoirs

Bibliography: p. 232-242

Influence of cyclic thermal treatments on the oxidation behavior of Ti-6Al- 2Sn-4Zr-2Mo alloy

Ti-6Al-2Sn-4Zr-2Mo is one of the most common titanium alloys for aerospace industry. This alloy experiences oxidation phenomenon at elevated temperatures. In the present study, cyclic thermal treatments were performed in air at 500, 593 and 700¿°C, up to 500¿cycles, in order to determine the oxidation kinetics and to analyze the oxide scale and alpha-case formation. Moreover, results were compared to those achieved under isothermal conditions to elucidate differences between both thermal conditions. In this sense, metallographic techniques and X-ray diffraction, together with a detailed advanced characterization of the microstructure by Field Emission Scanning Electron Microscopy and Focus Ions Beam, were used to analyze surface oxidation evolution. Results pointed out that cyclic treatments induced a strong increase of the weight gain compared to isothermal treatments. The analysis of the oxide scale revealed the formation of not only rutile, as isothermal treatments, but also anatase. Thickness of the oxide scale was higher for cyclic conditions, while alpha case did not exceed values reached by isothermal treatments and even became lower at 500¿°C.Peer Reviewe

Integrated engineering and architecture for the energy efficient academic buildings

In this paper, we outline a comprehensive and integrated collaboration between engineering and architecture team to build an energy efficient building. Within the framework of the EU FP7 project, titled NEED4B, we have been instrumental in design, construction and operation of a new highly energy efficient education building in the campus of Özyeğin University in Istanbul. The building was completed in 2013 although its monitoring will continue until 2018 to evaluate the performances of all subcomponents and that of the overall structure. The initial evaluation of the energy consumption of the building shows that it is better than the targeted value of 60 kWh/m2/year, following a detailed and integrated study. The details and the problems faced during this undertaking are discussed in the paper.European Commission ; FIBA Holdin

Integrated engineering and architecture for the energy efficient academic buildings

In this paper, we outline a comprehensive and integrated collaboration between engineering and architecture team to build an energy efficient building. Within the framework of the EU FP7 project, titled NEED4B, we have been instrumental in design, construction and operation of a new highly energy efficient education building in the campus of Özyeğin University in Istanbul. The building was completed in 2013 although its monitoring will continue until 2018 to evaluate the performances of all subcomponents and that of the overall structure. The initial evaluation of the energy consumption of the building shows that it is better than the targeted value of 60 kWh/m2/year, following a detailed and integrated study. The details and the problems faced during this undertaking are discussed in the paper.European Commission ; FIBA Holdin

Hong Kong Convention compliant ship recycling yard design for up to 30,000 dwt ships

The study is aimed to design a ship recycling yard in Indonesia which comply to the requirements stated in the Hong Kong Convention for the Safe and Environmentally Sound Recycling of Ships with the capacity up to 30,000 dwt. The study was conducted based on information gathered from field and literature survey. It is estimated that there are approximately 1,400 ships in Indonesia have reached more than 25 years, which need to be replaced by the new ones and will be sent for recycling, but there is not any ship recycling yard that is comply to the Hong Kong Convention requirements, and most of the ship recycling activities are carried out in traditional ways. It is expected that the proposed design will become a reference for ship recycling industry in Indonesia