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Micro-Technological Steps During the Fabrication of an AcHE Biosensor Designated to the Environment Monitoring
Cristian Ravariu,
Elena Manea,
Alina Popescu,
Cecilia Podaru,
Catalin Parvulescu
Issue:
Volume 3, Issue 3-1, June 2015
Pages:
1-6
Received:
14 February 2015
Accepted:
14 February 2015
Published:
12 March 2015
Abstract: Unfortunately, the pesticides pollute a large palette from environment: plants, organisms, soil and water. Using monitoring tools, like chemical biosensors, the use of pesticides can be put under control. Microelectronics offers the convenient transducers. Borrowing micro-technological processes, the enzymatic biosensors can be easily integrated onto the Silicon wafers. This paper proposes a biosensor for paraoxon pesticide detection, as a small piece from a decontamination soil technology plan. The paper reveals the pesticide detection principle, by paraoxon hydrolysis assisted by the Acetyl-cholinesterase enzyme, as key receptor. The enzyme is entrapped on a porous thin layer by adsorption. An advantageous method of the porous intermediate material anchored onto the Si-substrate, converting p-type Si in Si-porous by anodization, is described. Then, some technological steps, with tests and microscopy analysis are presented. Finally, the preliminary tests of the developed biosensor with the AcHE enzyme immobilized onto the Si-porous layer, are discussed.
Abstract: Unfortunately, the pesticides pollute a large palette from environment: plants, organisms, soil and water. Using monitoring tools, like chemical biosensors, the use of pesticides can be put under control. Microelectronics offers the convenient transducers. Borrowing micro-technological processes, the enzymatic biosensors can be easily integrated on...
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Different Work Regimes of an Organic Thin Film Transistor OTFT and Possible Applications in Bioelectronics
Cristian Ravariu,
Daniela Dragomirescu
Issue:
Volume 3, Issue 3-1, June 2015
Pages:
7-13
Received:
3 March 2015
Accepted:
3 March 2015
Published:
12 March 2015
Abstract: This paper presents an organic semiconductor transistor, with a vertical current modulation and a horizontal conduction. The simulations show a stronger top gate influence and establish four work regimes, depending on the top and bottom gates biasing. In the most favorable regime for the holes channel, under the reverse biased n+p junction, the holes/electrons current densities ratio reaches 0.168/269. However, an ambipolar OTFT function occurs under the reverse biasing of the vertical junction, with a top n-layer and a bottom p-layer. Due to the asymmetrical doping profile, the n+ channel conduction prevails in all the regimes. Therefore, the maximum current density of 1900A/cm2 is ensured by a double n channel, when both gates are positive biased. After simulations, three distinct work regimes are revealed by this single device: a SOI behavior with volume channel, a JFET with neutral median channel and an OTFT with one or more interface channels.
Abstract: This paper presents an organic semiconductor transistor, with a vertical current modulation and a horizontal conduction. The simulations show a stronger top gate influence and establish four work regimes, depending on the top and bottom gates biasing. In the most favorable regime for the holes channel, under the reverse biased n+p junction, the hol...
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Electronic Tool Interferences with Electrophysiology for the Psychiatric Disorders Monitoring
Florin Babarada,
Cristian Ravariu,
Dan Prelipceanu,
Bogdan Patrichi,
Daniela Manuc,
Aurora Salageanu,
Iuliana Caras
Issue:
Volume 3, Issue 3-1, June 2015
Pages:
14-21
Received:
24 March 2015
Accepted:
25 March 2015
Published:
3 April 2015
Abstract: The paper presents a hardware solution of the in vivo electrophysiological signals acquiring and processing, using a continuous data acquisition on PC. The originality of the paper comes from architecture proposal, with some new blocks, which selective amplify and filter biosignals. One of the major problems in the electrophysiological signals monitoring is the impossibility to record the weak signals from deep organs that are covered by noise and by strong cardiac or muscular artefact signals. The analogical processing block is based on a dynamic range compressor, containing the automatic gain control block, so that the high power signals are less amplified than the low components. The following block is a clipper since to capture all the transitions that escape from the dynamic range compressor. At clipper output a low-pass filter is connected since to abruptly cut the high specific bio-frequencies. The data vector recording is performing by strong internal resources microcontroller including ten bits A/D conversion port. Through some specific measurements and calibration the chain can be used to capture and then interprets the neuronal signal with well applications in public health monitoring like psychiatric disorders.
Abstract: The paper presents a hardware solution of the in vivo electrophysiological signals acquiring and processing, using a continuous data acquisition on PC. The originality of the paper comes from architecture proposal, with some new blocks, which selective amplify and filter biosignals. One of the major problems in the electrophysiological signals moni...
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Radiation Dose Risk and Diagnostic Benefit in Imaging Investigations
Lidia Dobrescu,
Gheorghe-Cristian Rădulescu
Issue:
Volume 3, Issue 3-1, June 2015
Pages:
22-26
Received:
28 March 2015
Accepted:
30 March 2015
Published:
11 April 2015
Abstract: The paper presents many facets of medical imaging investigations radiological risks. The total volume of prescribed medical investigations proves a serious lack in monitoring and tracking of the cumulative radiation doses in many health services. Modern radiological investigations equipment is continuously reducing the total dose of radiation due to improved technologies, so a decrease in per caput dose can be noticed, but the increasing number of investigations has determined a net increase of the annual collective dose. High doses of radiation are cumulated from Computed Tomography investigations. An integrated system for radiation safety of the patients investigated by radiological imaging methods, based on smart cards and Public Key Infrastructure allow radiation absorbed dose data storage.
Abstract: The paper presents many facets of medical imaging investigations radiological risks. The total volume of prescribed medical investigations proves a serious lack in monitoring and tracking of the cumulative radiation doses in many health services. Modern radiological investigations equipment is continuously reducing the total dose of radiation due t...
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A SSVEP Based EEG Signal Analysis to Discriminate the Effects of Music Levels on Executional Attention
Md. Kamrul Hasan,
Md. Shazzad Hossain,
Tarun Kanti Ghosh,
Mohiuddin Ahmad
Issue:
Volume 3, Issue 3-1, June 2015
Pages:
27-33
Received:
19 March 2015
Accepted:
17 April 2015
Published:
1 June 2015
Abstract: In this work the electrical activity in brain or known as electroencephalogram (EEG) signal is being analyzed to study the various effects of sound on the human brain activity. The effect is in the form of variation in either frequency or in the power of different EEG bands. A biological EEG signal stimulated by Music listening reflects the state of mind, impacts the analytical brain and the subjective-artistic brain. A two channel EEG acquisition unit is being used to extract brain signal with high transfer rate as well as good SNR. This paper focused on three types of brain waves which are theta (4-7 Hz), alpha (8-12 Hz) and beta wave (13-30 Hz). The analysis is carried out using Power Spectral density (PSD), Correlation co-efficient analysis. The outcome of this research depicted that high amplitude Alpha and low amplitude Beta wave and low amplitude Alpha and high amplitude Beta wave is associated with melody and rock music respectively meanwhile theta has no effect. High power of alpha waves and low power of beta waves that obtained during low levels of sound (Melody) indicate that subjects were in relaxed state. When subjects exposed to high level of sound (Rock), beta waves power increased indicating subjects in disturbed state. Meanwhile, the decrease of alpha wave magnitude showed that subjects in tense. Thus the subject’s executional attention level is determined by analyzing the different components of EEG signal.
Abstract: In this work the electrical activity in brain or known as electroencephalogram (EEG) signal is being analyzed to study the various effects of sound on the human brain activity. The effect is in the form of variation in either frequency or in the power of different EEG bands. A biological EEG signal stimulated by Music listening reflects the state o...
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