Biofunctionalized Patterned Polymer Brushes via Thiol-Ene Coupling for the Control of Cell Adhesion and the Formation of Cell Arrays

Thiol–ene radical coupling is increasingly used for the biofunctionalization of biomaterials. Thiol–ene chemistry presents interesting features that are particularly attractive for platforms requiring specific reactions with peptides or proteins and the patterning of cells, such as reactivity in physiological conditions and photoactivation. In this work, we synthesized alkene-functionalized (allyl and norbornene residues) antifouling polymer brushes (based on poly­(oligoethylene glycol methacrylate)) and studied thiol–ene coupling with a series of thiols including cell adhesive peptides RGD and REDV. The adhesion of umbilical vein endothelial cells (HUVECs) to these interfaces was studied and highlighted the absence of specific integrin engagement to REDV, in contrast to the high level of cell spreading observed on RGD-functionalized polymer brushes. This revealed that α₄β₁ integrins (binding to REDV sequences) are not sufficient on their own to sustain HUVEC spreading, in contrast to α_vβ₃ and α₅β₁ integrins. In addition, we photopatterned peptides at the surface of poly­(oligoethylene glycol methacrylate) (POEGMA) brushes and characterized the quality of the resulting arrays by epifluorescence microscopy and atomic force microscopy (AFM). This allowed the formation of cell patterns and demonstrated the potential of thiol–ene based photopatterning for the design of cell microarrays

3D modeling of magnetic field lines using SOHO/MDI magnetogram images

YesSolar images, along with other observational data, are very important for solar physicists and space weather researchers aiming to understand the way the Sun works and affects Earth. In this study a 3D modelling technique for visualizing solar magnetic field lines using solar images is presented. Photospheric magnetic field footpoints are detected from magnetogram images and using negative and positive magnetic footpoints, dipole pairs are associated according to their proximity. Then, 3D field line models are built using the calculated dipole coordinates, and mapped to detected pairs after coordinate transformations. Final 3D models are compared to extreme ultraviolet images and existing models and the results of visual comparisons are presented

Multiple Projection Optical Diffusion Tomography with Plane Wave Illumination

We describe a new data collection scheme for optical diffusion tomography in which plane wave illumination is combined with multiple projections in the slab imaging geometry. Multiple projection measurements are performed by rotating the slab around the sample. The advantage of the proposed method is that the measured data can be much more easily fitted into the dynamic range of most commonly used detectors. At the same time, multiple projections improve image quality by mutually interchanging the depth and transverse directions, and the scanned (detection) and integrated (illumination) surfaces. Inversion methods are derived for image reconstructions with extremely large data sets. Numerical simulations are performed for fixed and rotated slabs

Peptide Cross-Linked Poly(2-oxazoline) as a Sensor Material for the Detection of Proteases with a Quartz Crystal Microbalance

Inflammatory conditions are frequently accompanied by increased levels of active proteases, and there is rising interest in methods for their detection to monitor inflammation in a point of care setting. In this work, new sensor materials for disposable single-step protease biosensors based on poly(2-oxazoline) hydrogels cross-linked with a protease-specific cleavable peptide are described. The performance of the sensor material was assessed targeting the detection of matrix metalloproteinase-9 (MMP-9), a protease that has been shown to be an indicator of inflammation in multiple sclerosis and other inflammatory conditions. Films of the hydrogel were formed on gold-coated quartz crystals using thiol–ene click chemistry, and the cross-link density was optimized. The degradation rate of the hydrogel was monitored using a quartz crystal microbalance (QCM) and showed a strong dependence on the MMP-9 concentration. A concentration range of 0–160 nM of MMP-9 was investigated, and a lower limit of detection of 10 nM MMP-9 was determined

Diffusion of particles moving with constant speed

The propagation of light in a scattering medium is described as the motion of a special kind of a Brownian particle on which the fluctuating forces act only perpendicular to its velocity. This enforces strictly and dynamically the constraint of constant speed of the photon in the medium. A Fokker-Planck equation is derived for the probability distribution in the phase space assuming the transverse fluctuating force to be a white noise. Analytic expressions for the moments of the displacement $$ along with an approximate expression for the marginal probability distribution function $P(x,t)$ are obtained. Exact numerical solutions for the phase space probability distribution for various geometries are presented. The results show that the velocity distribution randomizes in a time of about eight times the mean free time ($8t^*$) only after which the diffusion approximation becomes valid. This factor of eight is a well known experimental fact. A persistence exponent of $0.435 \pm 0.005$ is calculated for this process in two dimensions by studying the survival probability of the particle in a semi-infinite medium. The case of a stochastic amplifying medium is also discussed.Comment: 9 pages, 9 figures(Submitted to Phys. Rev. E

Decoupling by clienteles and by time in the financial markets: the case of two-stage stock-financed mergers

A two-stage stock-financed merger occurs when an acquiring firm first issues shares, and then engages in a cash acquisition shortly afterward. Such deals allow us to test two important hypotheses derived from decoupling: by clienteles via segmentation and by time. The acquirer's value is maximized by selling shares to investors preferring to hold them, and use the raised cash to pay the target shareholders (the decoupling by clienteles hypothesis). Two-stage deals also provide an option to the acquirers by allowing them to decouple their own shares from the correlated target's shares by issuing at an earlier date and wait for good acquisition opportunities (the time decoupling hypothesis). We find empirical evidence in support of both hypotheses

Representation of solar features in 3D for creating visual solar catalogues

YesIn this study a method for 3D representation of active regions and sunspots that are detected from Solar and Heliospheric Observatory/Michelson Doppler Imager magnetogram and continuum images is provided. This is our first attempt to create a visual solar catalogue. Because of the difficulty of providing a full description of data in text based catalogues, it can be more accurate and effective for scientist to search 3D solar feature models and descriptions at the same time in such a visual solar catalogue. This catalogue would improve interpretation of solar images, since it would allow us to extract data embedded in various solar images and visualize it at the same time. In this work, active regions that are detected from magnetogram images and sunspots that are detected from continuum images are represented in 3D coordinates. Also their properties extracted from text based catalogues are represented at the same time in 3D environment. This is the first step for creating a 3D solar feature catalogue where automatically detected solar features will be presented visually together with their properties

Automated Prediction of CMEs Using Machine Learning of CME – Flare Associations

YesIn this work, machine learning algorithms are applied to explore the relation between significant flares and their associated CMEs. The NGDC flares catalogue and the SOHO/LASCO CMEs catalogue are processed to associate X and M-class flares with CMEs based on timing information. Automated systems are created to process and associate years of flares and CMEs data, which are later arranged in numerical training vectors and fed to machine learning algorithms to extract the embedded knowledge and provide learning rules that can be used for the automated prediction of CMEs. Different properties are extracted from all the associated (A) and not-associated (NA) flares representing the intensity, flare duration, duration of decline and duration of growth. Cascade Correlation Neural Networks (CCNN) are used in our work. The flare properties are converted to numerical formats that are suitable for CCNN. The CCNN will predict if a certain flare is likely to initiate a CME after input of its properties. Intensive experiments using the Jack-knife techniques are carried out and it is concluded that our system provides an accurate prediction rate of 65.3%. The prediction performance is analysed and recommendation for enhancing the performance are provided

Simulation of grid/standalone solar energy supplied reduced switch converter with optimal fuzzy logic controller using golden BallAlgorithm

This article presents the utilization of a shunt active power filter (SHAPF) in combination with an Energy Storage System (ESS) and a Solar Energy System (SES). Voltage source converters (VSC) are connected in parallel to a direct current (DC) bus. The membership function (MSF) of fuzzy logic controller (FLC) for the shunt control system is optimally adjusted using the golden balloptimization algorithm (GBOA). The present effort aims to achieve the following primary objectives: 1) Quick implementation to stabilize the voltage of the DC Link capacitor (DCLCV); 2) Mitigation of harmonics and improvement of power factor (PF); 3) Satisfactory performance under load as well as solar power varying conditions. The effectiveness of the optimally designed controller is evaluated by studying four test scenarios with grid and standalone conditions. The results are then compared to the existing sliding mode (SMC) and fuzzy logic controllers (FLC)

<記録II>ハミル館一〇〇年の歩み : 1918～2018

Renewable energy systems are of importance as being modular, nature-friendly and domestic. Among the renewable energy systems, a great deal of research has been conducted especially on photovoltaic, wind energy and fuel cell in the recent years. One of the hybrid renewable energy systems consisting of 5 kWp photovoltaic panels, 800 Wp wind turbines and 2.4 kWp fuel cell modules was installed at Clean Energy House (CEH), Pamukkale University in Denizli, Turkey. To protect this laboratory, a "Lightning Protection System" was installed at the CEH. In this study, design and installation processes of a lightning protection system for the hybrid renewable energy system at the CEH are considered. III. 7, bibl. 15 (in English; abstracts in English and Lithuanian)