Fullerene: biomedical engineers get to revisit an old friend

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New high-pressure phase of HfTiO4 and ZrTiO4 ceramics

We studied the high-pressure effects on the crystalline structure of monoclinic HfTiO₄ and ZrTiO₄. We found that the compressibility of these ceramics is highly non-isotropic, being the b-axis the most compressible one. In addition, the a-axis is found to have a small and negative compressibility. At 2.7 GPa (10.7 GPa) we discovered the onset of a structural phase transition in HfTiO₄ (ZrTiO₄), coexisting the low- and high-pressure phases in a broad pressure range. The new high-pressure phase has a monoclinic structure which involves an increase in the Ti-O coordination and a collapse of the cell volume. The equation of state for the low-pressure phase is also determined.     

The occurrence of perchlorate during drinking water electrolysis using BDD anodes

Electrochemical studies were carried out to estimate the risks of perchlorate formation in drinking water disinfected by direct electrolysis. Boron Doped Diamond (BDD) anodes were used in laboratory and commercially available cells at 20 °C. The current density was changed between 50 and 500 A m⁻². For comparison, other anode materials such as platinum and mixed oxide were also tested. It was found that BDD anodes have a thousandfold higher perchlorate formation potential compared with the other electrode materials that were tested. In long-term discontinuous experiments all the chloride finally reacted to form perchlorate. The same result was obtained when probable oxychlorine intermediates (OCl⁻, ClO₂⁻, ClO₃⁻) were electrolysed in synthetic waters in the ppm range of concentrations. The tendency to form perchlorate was confirmed when the flow rate of drinking water was varied between 100 and 300 L h⁻¹ and the temperature increased to 30 °C. In a continuous flow mode of operation a higher chloride concentration in the water resulted in a lower perchlorate formation. This can be explained by reaction competition of species near and on the anode surface for experiments both with synthetic and local drinking waters. It is concluded that the use of electrodes producing highly reactive species must be more carefully controlled in hygienically and environmentally oriented applications.     

FPGA realization of the LIRA neural classifier

Different types of neural networks can be used to classify images. We propose to apply LIRA (LImited Receptive Area) neural classifier to work with images. To accelerate the neural network functioning we propose a digital implementation of the LIRA neural classifier. We begin with a neuron design, and then continue with the neural network simulation. The advantage of neural network is its parallel structure and possibility of the training. FPGA (Field Programmable Gate Array) allows the implementation of these parallel algorithms in a single device. Speed of classification is one of the most important requirements in adaptive control systems based on computer vision. The contribution of this article is LIRA neural classifier implementation with FPGA for two classes to accelerate the training and recognition processes.     

Artificial gravity loading increases the effects of the glutamate transporter inhibitors on the glutamate release and uptake in rat brain nerve terminals

The present study evaluated the effect of artificial gravity loading on transporter-mediated uptake and release of L-glutamate using the inhibitors of glutamate transporters as tools. The competitive nontransportable, DL-threo-beta-benzyloxyaspartate (DL-TBOA), and transportable, DL-threo-beta-hydroxyaspartate (DL-THA), inhibitors were demonstrated to better inhibit the L-[¹⁴C]glutamate uptake under centrifuge-induced hypergravity compared with the normal gravity control. The effect of DL-TBOA on depolarization-induced carrier-mediated L-[¹⁴C]glutamate release also increased after hypergravity loading in Na⁺- and low [Na⁺] NMDG- supplemented media. 10 µM DL-TBOA-induced decrease in L-[¹⁴C]glutamate release in Na⁺ — supplemented medium was 15.2±2.2 % in the control experiments and 26.2±3.9 % after centrifuge-induced loading (P≤0,05) and in low [Na⁺] medium was 37.0±2.5 % and 45.0±3.4 %, respectively.     

Hybrid Photopatterned Enzymatic Reaction (HyPER) for in Situ Cell Manipulation

The ability to design artificial extracellular matrices as cell‐instructive scaffolds has opened the door to technologies capable of studying the fate of cells in vitro and to guiding tissue repair in vivo. One main component of the design of artificial extracellular matrices is the incorporation of biochemical cues to guide cell phenotype and multicellular organization. The extracellular matrix (ECM) is composed of a heterogeneous mixture of proteins that present a variety of spatially discrete signals to residing cell populations. In contrast, most engineered ECMs do not mimic this heterogeneity. In recent years, photo‐deprotection has been used to spatially immobilize signals. However, this approach has been limited mostly to small peptides. Here we combine photo‐deprotection with enzymatic reaction to achieve spatially controlled immobilization of active bioactive signals that range from small molecules to large proteins. A peptide substrate for transglutaminase factor XIII (FXIIIa) was caged with a photo‐deprotectable group, which was then immobilized to the bulk of a cell‐compatible hydrogel. With focused light, the substrate can be deprotected and used to immobilize patterned bioactive signals. This approach offers an innovative strategy to immobilize delicate bioactive signals, such as growth factors, without loss of activity and enables in situ cell manipulation of encapsulated cells.     

New proposal in the thermodynamic analysis of complex heat regeneration systems

This paper presents a new approach for analyzing and/or synthesizing the heat regeneration system, which has many applications in various energy conversion plants (ECP) and between ones. The method is applied for optimizing heat exchanger networks (HENs) operating below ambient temperature conditions as an application for refrigeration machines. Exergy and exergoeconomic methods are adapted for the optimization of three-flow heat exchangers. Few cases are illustrated and discussed. Also, the heuristic rules and design criteria for pinch analysis for an optimized HEN are presented.