Electrochemical assessment of the interaction of microbial living cells and carbon nanomaterials

This work considers the effects of various carbon nanomaterials and fibres on bioelectrocatalytic and respiratory activity of bacterial cells during the oxidation of ethanol in the presence of an electron transport mediator. Gluconobacter oxydans sbsp. industrius VKM B‐1280 cells were immobilised on the surfaces of graphite electrodes and had an adsorption contact with a nanomaterial (multi‐walled carbon nanotubes, thermally expanded graphite, highly oriented pyrolytic graphite, graphene oxide, reduced graphene oxide). The electrochemical parameters of the electrodes (the polarisation curves, the value of generated current at the introduction of substrate, the impedance characteristics) were measured in two‐electrode configuration. Modification by multi‐walled carbon nanotubes led to the increase of microbial fuel cell (MFC) electric power by 26%. The charge transfer resistance of modified electrodes was 47% lower than unmodified ones. Thermally expanded and pyrolytic graphites had a slight negative effect on the electrochemical properties of modified electrodes. The respiratory activity of bacterial cells did not change in the presence of nanomaterials. The data can be used in the development of microbial biosensors and MFC electrodes based on Gluconobacter cells.Inspec keywords: nanofabrication, catalysis, microorganisms, adsorption, charge exchange, microbial fuel cells, electrochemical electrodes, graphite, graphene, oxidation, multi‐wall carbon nanotubes, cellular biophysicsOther keywords: reduced graphene oxide, electrochemical parameters, two‐electrode configuration, multiwalled carbon nanotubes, microbial fuel cell, respiratory activity, bacterial cells, microbial biosensors, MFC electrodes, microbial living cells, electron transport mediator, graphite electrodes, adsorption contact, highly oriented pyrolytic graphite, Gluconobacter oxydans sbsp. industrius VKM B‐1280 cells, polarisation curves, bioelectrocatalytic activity, ethanol, thermally expanded graphite, charge transfer resistance, C     

Method for detecting and rectifying modular errors in devices for storing and transmitting information in measurement technology microprocessors

By way of discussion we consider a method for ensuring fail-free operation of discrete devices for storing and transmitting information, which utilizes linear codes for correcting modular errors. The method proposed makes it possible to extend the correction possibilities of a code, i.e., to rectify modular errors of any configuration under conditions when errors are detected in the remaining information modules. Translated from Izmeritel'naya Tekhnika, No. 11, pp. 11–15, November, 1999.     

Trauma and disaster as life disrupters: A model of computer-assisted psychotherapy applied to adolescent victims of the Chernobyl disaster.

This article reports on a computer-based, psychologist-assisted technology for addressing posttraumatic responses in Chernobyl-disaster-affected children. Mental health professionals who worked with this population reveal substantially distorted thoughts and feelings about the children's past, present, and future more than others of their age. Chernobyl-affected and evacuated children are aware that they can never return to their homes, illnesses may befall them in childhood, their parents may die sooner than normal, and that their environment is poisoned. The LifeLine psychotherapeutic software program (available from A. Kronik), which is based on the goal-and-causal theory of psychological time is described and suggestions are given for further school-based intervention and prevention services. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fabrication of Ti3SiC2-Ti4SiC3-SiC ceramic composites through carbosilicothermic reduction of TiO2

Dense Ti₃SiC₂-SiC, Ti₄SiC₃-SiC, and Ti₃SiC₂-Ti₄SiC₃-SiC ceramic composites were fabricated through carbosilicothermic reduction of TiO₂ under vacuum, followed by hot pressing of the as-synthesized products under 25 MPa at 1600°C. In the reduction step, SiC either alone or in combination with elemental Si was used as a reductant. A one-third excess of SiC was added in the reaction mixtures in order to ensure the presence of approximately 30 vol.% SiC in the products of synthesis. During the hot pressing step, the samples that contained Ti₃SiC₂ showed better densification compared to those containing Ti₄SiC₃. The obtained composites exhibited the strength properties typical of coarse-grained MAX-phase ceramics. The flexural strength values of 424 and 321 MPa were achieved in Ti₃SiC₂-SiC, and Ti₃SiC₂-Ti₄SiC₃-SiC composites, respectively. The fracture toughness values were 5.7 MPa·m^1/2.     

Ultrafast gas chromatography on single-wall carbon nanotube stationary phases in microfabricated channels

The key to rapid temperature programmed separations with gas chromatography are a fast, low-volume injection and a short microbore separation column with fast resistive heating. One of the major problems with the reduction of column dimensions for micro gas chromatography is the availability of a stationary phase that provides good separation performance. In this report, we present the first integration of single-wall carbon nanotubes (SWNTs) as a stationary phase into 100 mum x 100 mum square and 50-cm-long microfabricated channels. The small size of this column with integrated resistive heater and the robustness of the SWNT phase allow for fast temperature programming of up to 60 degrees C/s. A combination of the fast temperature programming and the narrow peak width of small-volume injections that can be obtained from a high-speed, dual-valve injection system allows for rapid separations of gas mixtures. We demonstrate highly reproducible separations of four-compound test mixtures on these columns in less than 1 s using fast temperature programming.     

Infrared zone-scanning system

Challenges encountered in designing an infrared viewing optical system that uses a small linear detector array based on a zone-scanning approach are discussed. Scanning is performed by a rotating refractive polygon prism with tilted facets, which, along with high-speed line scanning, makes the scanning gear as simple as possible. A method of calculation of a practical optical system to compensate for aberrations during prism rotation is described.     

Airborne digital holographic system for cloud particle measurements

An in-line holographic system for in situ detection of atmospheric cloud particles [Holographic Detector for Clouds (HOLODEC)] has been developed and flown on the National Center for Atmospheric Research C-130 research aircraft. Clear holograms are obtained in daylight conditions at typical aircraft speeds of 100 m s(-1). The instrument is fully digital and is interfaced to a control and data-acquisition system in the aircraft via optical fiber. It is operable at temperatures of less than -30 degrees C and at typical cloud humidities. Preliminary data from the experiment show its utility for studies of the three-dimensional spatial distribution of cloud particles and ice crystal shapes.     

Artificial Neuron and Synapse Realized in an Antiferromagnet/Ferromagnet Heterostructure Using Dynamics of Spin–Orbit Torque Switching

Efficient information processing in the human brain is achieved by dynamics of neurons and synapses, motivating effective implementation of artificial spiking neural networks. Here, the dynamics of spin–orbit torque switching in antiferromagnet/ferromagnet heterostructures is studied to show the capability of the material system to form artificial neurons and synapses for asynchronous spiking neural networks. The magnetization switching, driven by a single current pulse or trains of pulses, is examined as a function of the pulse width (1 s to 1 ns), amplitude, number, and pulse‐to‐pulse interval. Based on this dynamics and the unique ability of the system to exhibit binary or analog behavior depending on the device size, key functionalities of a synapse (spike‐timing‐dependent plasticity) and a neuron (leaky integrate‐and‐fire) are reproduced in the same material and on the basis of the same working principle. These results open a way toward spintronics‐based neuromorphic hardware that executes cognitive tasks with the efficiency of the human brain.     

Current transfer processes in a hydrated layer localized in a two-layer porous structure of nanosized ZrO2

Journal of Materials Science: Materials in Electronics - The current transfer through a two-layer structure saturated with absorbed water, each layer of which consists of pressed ZrO2 nanoparticles...