Krzysztof Zaraska

Instytut Technologii Elektronowej, Warszawa, Masovian Voivodeship, Poland

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Publications (8)5.64 Total impact

  • Applied Mechanics and Materials. 10/2011;
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    ABSTRACT: Vagus nerve as a part of brain-gut axis transmits peripheral information to the brain via vagovagal reflexes. Electric properties of the vagus are not exactly known. Analysis of electric changes in vagal nerves evoked by physiologic impulse such as stomach distention by food would facilitate applying better documented and therefore safer vagal neuromodulation. The aim of our study was analysis and interpretation of electric properties of the left vagus in vivo in fasted and satiated Wistar rats. Silver measuring electrodes connected to analog amplifier (A-M Systems 3000) were attached to the nerve in the neck region. The signal was filtered and probing by computer recording system (ADInstruments Power Lab) and additional analyses were performed using GNU Octave programme. Our resuts have shown that the higher amplitude the smaller number of counted impulses in the vagus was detected. This relationship was true only till the maximum level typical for each recording (about 15-20 dB). We note that observed inter spike interval can be approximated with log-normal distribution, and that its mu parameter is enough to characterize a particular recording. Satiated rats were characterized by higher number of spikes per second in the nerve than fasted ones (0.9 vs 0.26) indicating that food intake increased nervous activity 3-4 times comparing to fasted state. The outcomes encourage us to state that good quality characteristic of the left vagus nerve activity provides an effective tool for detection of peripheral signals which are transmitting via vagal afferents to the higher centres. Target vagal neuromodulation to obtain certain terapeutic effects may be possible.
    Folia medica Cracoviensia 01/2011; 51(1-4):5-17.
  • E Klimiec, K Zaraska, W Zaraska
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    ABSTRACT: Parasitic harvesting of energy from environment is being investigated as a possible solution for powering electronic devices. One possible solution is to harvest energy generated from human walking, by placing a piezoelectric elements inside footwear. As the amount of available energy is extremely low, conversion effectiveness is of prime importance. This paper deals with a micropower source, designed to harvest energy from walking, built in a form of a shoe insole containing a piezoelectric material (43??m thick polyethylene foil). Laboratory investigation of the piezoelectric properties is presented first, followed by a measurement result of an actual generator with 0·6??W output power. Finally, a modification of the generator, by adding springy elements, is presented, resulting in ninefold increase in power output (to 5·6??W).AbstractParasitic harvesting of energy from environment is being investigated as a possible solution for powering electronic devices. One possible solution is to harvest energy generated from human walking, by placing a piezoelectric elements inside footwear. As the amount of available energy is extremely low, conversion effectiveness is of prime importance. This paper deals with a micropower source, designed to harvest energy from walking, built in a form of a shoe insole containing a piezoelectric material (43??m thick polyethylene foil). Laboratory investigation of the piezoelectric properties is presented first, followed by a measurement result of an actual generator with 0·6??W output power. Finally, a modification of the generator, by adding springy elements, is presented, resulting in ninefold increase in power output (to 5·6??W).
    Advances in Applied Ceramics 02/2010; 109(1):152-155. · 0.69 Impact Factor
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    ABSTRACT: Vagus nerve (VN) contribute to the bidirectional communication between the gastrointestinal tract and the central nervous system. Stimulation of the VN by a magnetically-driven solenoid with parameters similar to those during food-induced stomach distension has been thought to mimic short-term signaling of satiety and suppress food intake. In this study, the determination of optimal parameters of vagal neuro-modulation to achieve decreased food intake with a resulting reduction in body mass of rats is explored as therapy to treat obesity. The experimental design consisted of three groups of obese adult male Wistar rats: Group 1: VEMF - with solenoid's electrodes placed on the left VN in the magnetic field exposure (MFE); Group 2: EMF - without solenoid's electrodes on the VN in MFE; Group 3: CON - without solenoid's electrodes on the VN outside the MFE. This study suggests that the rats with solenoid's electrodes placed on the left VN significantly decreased their food intake, weight gain and serum leptin concentrations when compared to that of the CON group. PP levels were found to be higher in the VEMF group when compared to the controls groups. It was found that the most effective parameters of vagal stimulation on eating behavior were 3631, 7861, 14523 A(2) x h/m(2). The magnetic field by unknown mechanisms also influences feeding behavior. This study suggests that vago-vagal reflexes are involved in the feeding homeostasis and that neuromodulation might be an effective method for managing obesity. Further studies are required to confirm these effects in humans.
    Journal of physiology and pharmacology: an official journal of the Polish Physiological Society 09/2009; 60(3):71-7. · 2.48 Impact Factor
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    ABSTRACT: Piezoelectric polymer film material allows for conversion of mechanical energy into electrical energy that can be used for supplying electronic devices. While this method does not allow obtaining large useful power, recent advances in electronic technology, in particular wide availability of submicron low-power CMOS processes, have made feasible the idea of using piezoelectric polymers as power converters for human powered electronics. This concept allows to overcome the necessity of using battery as a power source, which is one of the main obstacles to widespread adoption of wearable computing devices. Of particular interest is harvesting energy from walking, which can be achieved by using piezoelectric polymers. In this paper maximum power has been calculated that can be drawn from walking energy owing to application of the copolymer polyethylene–polypropylene (PE–PP) shoe insole. The amount of electric energy obtained from a PE–PP foil of a thickness of 11μm for a single step of a duration of 1 s – that is equivalent to a frequency of 1Hz – amounts to 340nJ.
    Microelectronics Reliability. 01/2008; 48:897-901.
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    ABSTRACT: Because of the undeniable advantages of powder electroluminescent light sources the authors have designed and tested an animated thick film electroluminescent advertising panel. The paper describes the design steps and phases of the technological process. Finally, the brightness characteristics and influence of color translucent inks covering the segments are presented. The expected life time of the electroluminescent structure under normal exploitation conditions is evaluated.
    Electron Technology - Internet Journal. 01/2006;
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    ABSTRACT: In many therapeutic processes the future medicine will go away from the traditional pharmacological methods and will apply active stimulation of organs with implanted neurostimulators. The classical examples are nowadays the pacemakers. From the inspiration of Pathophysiology Department in Collegium Medicum of Jagiellonian University the Institute of Electron Technology undertook the research work in the field of implanted neurostimulators. The authors presented in the paper the hitherto achieved results of research works, including the analysis of electrical signals course in excited and non-excited vagus nerve and impedance measurement of nerve fibre, necessary for determining the parameters of neurostimulator such as the amplitude, duration and the repetition rate of stimulator pulses. From the point of view of circuit theory neurostimulator is a kind of self-excited or microprocessor controlled pulse generator. In the paper the structure of neurostimulator is presented and the choice of electrodes material and encapsulation resin is explained, taking into account the problem of biocompatibility. Some experimental results of laboratory tests on experimental animals with implanted neurostimulators are shown.
    Microelectronics Reliability. 01/2005;
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    ABSTRACT: Afferent fibers from gastrointestinal tract outnumber efferents ten times in vagal nerves. Modifying the afferent input makes possible to change discharge of vagal efferents affecting gastrointestinal functions in process known as neuromodulation (NM). Lately it has been used in the treatment of pain and hyperactive neurogenic bladder in urology. MC induced NM may therefore provide a concurrent to pharmacology tool, in treatment of gastrointestinal disorders. The aim of this study was to investigate the effects of long term neuromodulation procedure with use of MC on gastric motility, secretion and weight control in conscious rats. Experiments were performed on 30 Wistar male rats (250-350 g) divided in two groups: sham operated and microsurgically implanted with MC on left vagal nerve below diaphragm. Following stimulation parameters were used: frequency of 0.5-30 Hz, amplitude of 0.55 V, impulse duration of 10 ms in monophasic fashion. In both groups food intake and body weight were measured through the period of 2 weeks after recovery period. Then gastric fistula was implanted in gastric antrum and fasted gastric motility recorded with use of PowerLab system (Australia). Gastric emptying and secretion were also tested with use of phenol red and automatic titration methods. On the daily basis glucose level with standard test and leptin after MC implantation were measured. Recording of vagal activity in fasted rats showed burst of action potentials about 5 +/- 2.5 in period of 5000 sec, each burst with spike frequency up to 35 Hz. Food (5 ml of Intralipid--intragastrically) almost doubled amount of bursts to 12 +/- 5 in period of 5000 sec with increase in frequency at spike up to 50 Hz. MC induced vagal activity showed continuous spike activity similar to fed pattern. MC induced NM decreases daily food intake by 6% (33.6 +/- 4.8 vs control 35.5 +/- 4.8 g, p < 0.01). Body weight gain in rats before MC implantation decreased by 20% within 2 weeks after recovery (34.8 +/- 9.08 vs control 23.56 +/- 4.15 g). Fasting control glucose level also decreased of 5.5% (93.15 +/- 9.3 vs control 98.5 +/- 11.2 mg%, p < 0.05). Frequency of gastric contractions did not change significantly in MC versus control but amplitude of contractions increased of about 66.7% (2.0 +/- 0.8 vs 1.17 +/- 0.52) at the dominant frequency 0.08 Hz range and about 71.5% (1.17 +/- 0.35 vs 0.68 +/- 0.47, p < 0.05) at the frequency 0.12 Hz. in FFT analysis PowerLab (chart v = 4.01). BAO decreased by 29.25% without H+ concentration changes (0.2 +/- 0.14 vs 0.14 +/- 0.12 mmol/30 min, p < 0.05) but MAO did not change in MC rats (0.37 +/- 0.25 vs 0.42 +/- 0.28 mmol/30 min, p 0.05). Gastric emptying of isotonic solution increased by 10% (90.46 +/- 5.34 vs 80.39 +/- 9.95) percent of marker passing to duodenum/5 min, p < 0.0001). Our results suggest that MC induced NM affect brain-gut axis via influencing metabolic and gastric function and decreases body weight.
    Journal of physiology and pharmacology: an official journal of the Polish Physiological Society 12/2001; 52(4 Pt 1):705-15. · 2.48 Impact Factor