A new gas discharge process for preparation of non-fouling surfaces on biomaterials

A non-fouling surface containing immobilized polyethylene oxide (PEO) was achieved using an argon radio-frequency glow discharge treatment (RFGD) of polyethylene films precoated with Brij hydrocarbon-PEO surfactants. Surface wettability of RFGD-treated and washed surfaces increased the most when PEO surfactants with unsaturated and/or long alkyl tails were used. ESCA measurements of treated and washed surfaces showed increases of surface O/C ratios and ether carbon peaks in high resolution Cls spectra. These results demonstrate the retention of the PEO surfactants on the treated surfaces. Fibrinogen adsorp tion on these treated surfaces was significantly reduced, from 500 to 50 ng/cm2, indicating the non-fouling properties of the RFGD-immobilized PEO surfactants

Modeling of convection phenomena in Bridgman-Stockbarger crystal growth

Thermal convection phenomena in a vertically oriented Bridgman-Stockbarger apparatus were modeled by computer simulations for different gravity conditions, ranging from earth conditions to extremely low gravity, approximate space conditions. The modeling results were obtained by the application of a state-of-the art, transient, multi-dimensional, completely densimetrically coupled, discrete-element computational model which was specifically developed for the simulation of flow, temperature, and species concentration conditions in two-phase (solid-liquid) systems. The computational model was applied to the simulation of the flow and the thermal conditions associated with the convection phenomena in a modified Germanium-Silicon charge enclosed in a stationary fused-silica ampoule. The results clearly indicated that the gravitational field strength influences the characteristics of the coherent vortical flow patterns, interface shape and position, maximum melt velocity, and interfacial normal temperature gradient

Concerted activities of Mcm4, Sld3 and Dbf4 in control of origin activation and DNA replication fork progression

Eukaryotic chromosomes initiate DNA synthesis from multiple replication origins in a temporally specific manner during S phase. The replicative helicase Mcm2-7 functions in both initiation and fork progression and thus is an important target of regulation. Mcm4, a helicase subunit, possesses an unstructured regulatory domain that mediates control from multiple kinase signaling pathways, including the Dbf4-dependent Cdc7 kinase (DDK). Following replication stress in S phase, Dbf4 and Sld3, an initiation factor and essential target of Cyclin-Dependent Kinase (CDK), are targets of the checkpoint kinase Rad53 for inhibition of initiation from origins that have yet to be activated, so-called late origins. Here, whole genome DNA replication profile analysis is employed to access under various conditions the effect of mutations that alter the Mcm4 helicase regulatory domain and the Rad53 targets, Sld3 and Dbf4. Late origin firing occurs under genotoxic stress when the controls on Mcm4, Sld3 and Dbf4 are simultaneously eliminated. The regulatory domain of Mcm4 plays an important role in the timing of late origin firing, both in an unperturbed S phase and dNTP limitation. Furthermore, checkpoint control of Sld3 impacts fork progression under replication stress. This effect is parallel to the role of the Mcm4 regulatory domain in monitoring fork progression. Hypomorph mutations in sld3 are suppressed by a mcm4 regulatory domain mutation. Thus, in response cellular conditions, the functions executed by Sld3, Dbf4 and the regulatory domain of Mcm4 intersect to control origin firing and replication fork progression, thereby ensuring genome stability

Motion video compression system with neural network having winner-take-all function

A motion video data system includes a compression system, including an image compressor, an image decompressor correlative to the image compressor having an input connected to an output of the image compressor, a feedback summing node having one input connected to an output of the image decompressor, a picture memory having an input connected to an output of the feedback summing node, apparatus for comparing an image stored in the picture memory with a received input image and deducing therefrom pixels having differences between the stored image and the received image and for retrieving from the picture memory a partial image including the pixels only and applying the partial image to another input of the feedback summing node, whereby to produce at the output of the feedback summing node an updated decompressed image, a subtraction node having one input connected to received the received image and another input connected to receive the partial image so as to generate a difference image, the image compressor having an input connected to receive the difference image whereby to produce a compressed difference image at the output of the image compressor

Prehypertensive blood pressures and regional cerebral blood flow independently relate to cognitive performance in midlife

Background High blood pressure is thought to contribute to dementia in late life, but our understanding of the relationship between individual differences in blood pressure ( BP ) and cognitive functioning is incomplete. In this study, cognitive performance in nonhypertensive midlife adults was examined as a function of resting BP and regional cerebral blood flow ( rCBF ) responses during cognitive testing. We hypothesized that BP would be negatively related to cognitive performance and that cognitive performance would also be related to rCBF responses within areas related to BP control. We explored whether deficits related to systolic BP might be explained by rCBF responses to mental challenge. Methods and Results Healthy midlife participants (n=227) received neuropsychological testing and performed cognitive tasks in a magnetic resonance imaging scanner. A pseudocontinuous arterial spin labeling sequence assessed rCBF in brain areas related to BP in prior studies. Systolic BP was negatively related to 4 of 5 neuropsychological factors (standardized β&gt;0.13): memory, working memory, executive function, and mental efficiency. The rCBF in 2 brain regions of interest was similarly related to memory, executive function, and working memory (standardized β&gt;0.17); however, rCBF responses did not explain the relationship between resting systolic BP and cognitive performance. Conclusions Relationships at midlife between prehypertensive levels of systolic BP and both cognitive and brain function were modest but suggested the possible value of midlife intervention. </jats:sec

Differential Game for Environmental-Regulation in Green Supply Chain

[[abstract]]This paper demonstrates that a proper design of environmental-regulation pricing strategies is able to promote Extended Product Responsibility for green supply chain firms in a competitive market. A differential game model comprising Vidale-Wolfe equation has been established in light of sales competition and recycling dynamics as well as regulation related profit function. Analytic solutions of Markovian Nash equilibriums are provided with the necessary condition derived from Hamilton-Jacobi-Bellman equations. We found that governments should opt to gradually raise regulation standards so that rational manufacturers will gradually improve its product recyclability, and, in turn, Extended Product Responsibility will get promoted

Immobilization of Polyethylene Oxide Surfactants for Non-Fouling Biomaterial Surfaces Using an Argon Glow Discharge Treatment

A non-fouling (protein-resistant) polymer surface is achieved by the covalent immobilization of polyethylene oxide (PEO) surfactants using an inert gas discharge treatment. Treated surfaces have been characterized using electron spectroscopy for chemical analysis (ESCA), static secondary ion mass spectrometry (SSIMS), water contact angle measurement, fibrinogen adsorption, and platelet adhesion. This paper is intended to review our recent work in using this simple surface modification process to obtain wettable polymer surfaces in general, and non-fouling biomaterial surfaces in particular

Polaronic transport induced by competing interfacial magnetic order in a La0.7_{0.7}Ca0.3_{0.3}MnO3_{3}/BiFeO3_{3} heterostructure

Using ultrafast optical spectroscopy, we show that polaronic behavior associated with interfacial antiferromagnetic order is likely the origin of tunable magnetotransport upon switching the ferroelectric polarity in a La$_{0.7}$Ca$_{0.3}$MnO$_{3}$/BiFeO$_{3}$ (LCMO/BFO) heterostructure. This is revealed through the difference in dynamic spectral weight transfer between LCMO and LCMO/BFO at low temperatures, which indicates that transport in LCMO/BFO is polaronic in nature. This polaronic feature in LCMO/BFO decreases in relatively high magnetic fields due to the increased spin alignment, while no discernible change is found in the LCMO film at low temperatures. These results thus shed new light on the intrinsic mechanisms governing magnetoelectric coupling in this heterostructure, potentially offering a new route to enhancing multiferroic functionality