Search results

1

2×2 MIMO VLC Optical Transmission System Based on LEDs in a Double Role

100%

Kowalczyk M.

Acta Physica Polonica A

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2016

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vol. 130

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issue 1

41-44

EN

The article presents the concept solution of two main issues of visible light communication systems, i.e. the lack of a cost-effective feedback channel and the handling of high throughput. The concept is based on merging of the multiple input multiple output approach, well-known from radio transmission domain, with using of LEDs in a double role, i.e. both as emitters and detectors of light. The feasibility of the proposal was confirmed by the results of the research, carried out for two-channel system of this type.

2

Influence of CCK-8 and yohimbine on supraspinal modulation of nociceptive process

64%

Szymbor B., Kowalczyk M.

Acta Neurobiologiae Experimentalis

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1996

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vol. 56

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issue 1

243-248

EN

We studied the effect of cholecystokinin (CCK-8) and yohimbine - (alpha)-2-adrenoreceptor antagonist administered locally into lateral reticular formation (LRF) on the bioelectrical response to the pain stimulation. The experiments were carried out on 8 concious rabbits with bilatrally implanted electrodes into: motor-sensory cortex, ventro-postero-lateral thalamic nuclei, hippocampus and LRF. Nociceptive stimulation was performed by means of electrical pulses applied to the front paw. Bioelectrical activity (BA) of the chosen brain structures was analysed by means of spectral analysis (FFT) and directed transfer function (DTF). The results of our study may suggest that supraspinal administration of CCK-8 together with yohimbine have inhibitory effect on nociceptive transmission.

3

Insulin impairs the anticonvulsive activity of carbamazepine against maximal electroshock-induced seizures in mice

51%

Alaraj M., Pieniak M., Kowalczyk M., Kosinska I.

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vol. 58

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issue 4

283-286

EN

In view of the data indicating that insulin can modify penetration of some drugs across cell membranes and tissue barriers, particularly the blood-brain barrier, the aim of the present study was to evaluate the effect of insulin on both the anticonvulsant activity and the brain concentration of carbamazepine in mice suffering from seizures induced by maximal electroshock. The antiepileptic drug was administered per os in single doses either alone or in combination with insulin given as single intraperitoneal injections. To assess the anticonvulsant activity of carbamazepine the ED50 values were calculated. The results indicate that insulin given in doses up to 2 units/kg did not affect the convulsive threshold, whereas insulin applied at 2 units/kg led to a significant reduction in the anticonvulsant activity of carbamazepine, as judged by an increase in the ED50 value from 16.2 to 41.3 mg/kg. This effect was accompanied by the marked reduction in both the brain and blood concentrations of the drug. It is likely, therefore, that the inhibitory activity of insulin on the anticonvulsive function of carbamazepine is related not only to the effect of the former on the blood-brain transport of the latter, but also to insulin-induced modulation of the serum concentration of the drug.

4

Chromosome abnormalities without phenotypic consequences

51%

Kowalczyk M., Srebniak M., Tomaszewska A.

Journal of Applied Genetics

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2007

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vol. 48

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issue 2

157-166

EN

Some changes in chromosome morphology, detected during cytogenetic analysis, are not associated with clinical defects. Therefore a proper discrimination of harmless variants from true abnormalities, especially during prenatal diagnosis, is crucial to allow precise counseling. In this review we described chromosome variants and examples of chromosome anomalies that are considered to be unrelated to phenotypic consequences. The correlation between the presence of marker chromosomes and a risk of clinical signs is also discussed. Structural rearrangements of heterochromatic material, satellite polymorphism, or fragile sites, are well-known examples of common chromosome variation. However, the absence of clinical effects has also been reported in some cases of chromosome abnormalities concerning euchromatin. Such euchromatic anomalies were divided into 2 categories: unbalanced chromosome abnormalities (UBCAs), such as deletions or duplications, and euchromatic variants (EVs). Recently so-called molecular karyotyping, especially whole-genome screening by the use of high-resolution array-CGH technique, contributed to revealing a high number of previously unknown small genomic variations, which seem to be asymptomatic, as they are present in phenotypically normal individuals.

5

Reuse of "end of life tyres

51%

Dembicki E., Kowalczyk M., Gotteland P.

Archives of Civil Engineering

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2012

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issue 3

6

Entropy Change Calculations for Pure Gd and a Ni-Mn-Cu-Ga Heusler Alloy: Constant Field vs. Constant Temperature Experiment

39%

Ferenc J., Kowalczyk M., Wróblewski R., Cieślak G., Sielicki K., Leonowicz M., Kulik T.

Acta Physica Polonica A

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2015

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vol. 128

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issue 1

111-115

EN

The magnetocaloric effect may be assessed indirectly by expressing it as the change in magnetic entropy in varying magnetic field, H, as the function of temperature, T. Magnetization, M=f(T,H), may be experimentally acquired from a series of isothermal measurements with variable field, or from a series of constant field measurements with variable temperature. The accuracy of magnetic entropy calculation depends on the number of series in these experiments. The aim of this work is to determine how little data is sufficient to obtain accurate results of magnetic entropy change calculations, on the basis of real, magnetocaloric materials. Pure gadolinium and a Ni-Mn-Cu-Ga Heusler alloy were studied. For both materials, the magnetic entropy change and relative cooling power were calculated from both experiments, with the decreasing number of experimental data. For both materials, the constant field experiment with only 6 field values provided only a 5% error of calculations, as compared to the experiment with 100 field values. The Arrott plots were also drawn for constant field mode with 6 field values, easily indicating the order of transition. Comparison of the calculation results suggests that the constant field mode magnetization measurement may be more accurate and faster than isothermal mode.

7

The Evolution of Microstructure and Magneto-structural Properties of Heat Treated NI-MN-SN-IN Heusler Alloys Sintered by Vacuum Hot Pressing

33%

Maziarz W., Wojcik A., Chulist R., Szczerba M. J., Kowalczyk M., Czaja P., Cesari E., Dutkiewicz J.

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2019

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vol. 64

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issue 2

8

X-Rays Response of Diamond Detectors Constructed Using Diamond Layers Produced by Low Power Microwave Chemical Vapor Deposition Reactor

27%

Kordyasz A., Bednarek A., Kowalczyk M., Tarasiuk J., Kulczycka E., Teodorczyk M., Gajewski M., Kordyasz Ł., Rowiński O., Lamparski K., Karwański Ł., Lipczewski T.

Acta Physica Polonica A

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2015

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vol. 127

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issue 5

1555-1559

EN

The low power reactor for microwave chemical vapor deposition process is described. The rotating Mo holder of 12 mm diameter and 6 mm height with the diamond substrate was heated by 2.45 GHz microwaves to temperature about 800°C in the range of (1.5-7)% CH_{4}/H_{2} mixture to create plasma at pressure 70 Tr. Stabilization of the holder temperature was performed by optical observation of radiation from the holder followed by adjusting of the magnetron power. Diamond detectors are produced using microwave chemical vapor deposition process grown on single crystal diamond high pressure high temperature Sumimoto substrates, [100] oriented. The response of diamond detectors for X-rays has been measured in the current mode using medical X-rays tube. The linear response of the diamond detector current versus X-ray tube current (dose) is presented.

Refine search results

2×2 MIMO VLC Optical Transmission System Based on LEDs in a Double Role

Influence of CCK-8 and yohimbine on supraspinal modulation of nociceptive process

Insulin impairs the anticonvulsive activity of carbamazepine against maximal electroshock-induced seizures in mice

Chromosome abnormalities without phenotypic consequences

Reuse of "end of life tyres

Entropy Change Calculations for Pure Gd and a Ni-Mn-Cu-Ga Heusler Alloy: Constant Field vs. Constant Temperature Experiment

The Evolution of Microstructure and Magneto-structural Properties of Heat Treated NI-MN-SN-IN Heusler Alloys Sintered by Vacuum Hot Pressing

X-Rays Response of Diamond Detectors Constructed Using Diamond Layers Produced by Low Power Microwave Chemical Vapor Deposition Reactor