Wyniki wyszukiwania - Biblioteka Nauki

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Udział synaps elektrycznych w generowaniu hipokampalnego rytmu theta in vivo

100%

Gołebiewski H. , Eckersdorf B. , Konopacki J. , Uniwersytet Łódzki K. N.

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tom 3

PL

W obecnych doświadczeniach badano rol. synaps elektrycznych formacji hipokampa w generowaniu lokalnie rejestrowanego rytmu theta u swobodnie poruszających się kotów. Dohipokampalne mikroiniekcje karbenoksolonu oraz chininy (30|ag/l „ 1) odwracalnie obniżały amplitudę i moc hipokampalnego rytmu theta występującego spontanicznie, jak i wywołanego drażnieniem czuciowym czy elektrycznym formacji siatkowatej śródmózgowia. Hamujący wpływ ujawnił się w 30 minut po mikroiniekcji i obserwowany był przez około 9 godzin od podania każdego z zastosowanych środków farmakologicznych. Następnie oba parametry aktywności rytmicznej stopniowo wracały do wartości kontrolnych. Częstotliwość rytmu nie ulegała zmianom przez cały czas doświadczeń. Wyniki uzyskane w obecnych badaniach dostarczają pierwszych bezpośrednich dowodów wskazujących na istotny udział synaps elektrycznych formacji hipokampa w mechanizmach synchronizacji leżących u podstaw generowania rytmu theta w warunkach in vivo.

2

Impact of some external factors on the values of mechanical parameters determined in tests on bone tissue

88%

Nikodem A. , Ścigała K.

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tom Vol. 12, no. 3

85-93

EN

The knowledge of the mechanical characteristics of bone structures is a prerequisite for theoretical, numerical, and experimental analyses describing the functioning of bone, which is a living organ. The description of the mechanical properties of bone tissue, such as conventional Young’s modulus or strength, will enable the assessment of the degree of tissue degeneration through a comparison of the material properties of the examined bones to the properties determined for physiologically normal bones. However, the mechanical parameters published by different research centres often differ from each other by up to several hundred percent. These discrepancies arise primarily from the differences in the research methodology applied, and thus from many additional factors having a direct impact on the values of the mechanical parameters obtained in experimental tests. Therefore, in order to standardize and improve the interpretation of the results of measurements, we should develop universal criteria for the measuring conditions and quantify the impact of the factors being related to sample and measurements on the values obtained. In this paper, the authors present the dependence of some factors, i.e. the site and direction of sample excision as well as the rate and type of loading, on the values of the mechanical parameters. Those values were determined in experimental tests and the additional correlation coefficients proposed enabled an easier comparison of the results obtained with the values presented in the literature.

3

Assessment of the lactide-co-glycolide and its composite degradation velocity under in vitro and in vivo conditions

88%

Chłopek J. , Morawska-Chochół A.

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2007

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tom Vol. 7, nr 2(12)

86-91

EN

The aim of this work was the analysis of the modifying phase effect (hydroxyapatite particles and carbon fibres) and environment role (in vitro and in vivo) on mechanism and velocity of the resorption process of polylactide-co-glycolide (PGLA). Resorption time of samples incubated in simulated biological environment was determined on the basis of pH changes of the Ringer's solution. Scanning electron microscopy and infrared spectroscopy were applied for the estimation of the resorption degree of the polymer. It was observed that carbon fibres addition accelerates distinctly in vitro matrix degradation, whereas in the natural biological environment fibres reduce this time. In the case of composite with hydroxyapatite nanoparticles the in vitro processes are complex and difficult to explain. In this case simultaneous occurrence of three processes is possible: polymer resorption, HAP precipitation and dissolution. In the biological environment reduce polymer resorption time is no-ticeable.

4

Mesoporous alumina as a biomaterial for biomedical applications

63%

Xifre-Perez E. , Ferre-Borull J. , Pallares J. , Marsal L. F.

Mesoporous Biomaterials

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2015

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tom 2

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nr 1

EN

Porous anodic alumina (PAA) is a biomaterial based on a cost-effective electrochemical anodization of pure aluminum with unique geometrical properties, i.e., self-ordering hexagonal pore distribution, tunable pore diameters and interpore distances, and uniformity of the pores in the vertical direction (nanochannels). These remarkable properties have found important applications in several fields such as energy storage, optics, photonics, magnetism, catalysis and, in particular, in the biomedicine field. In this work, we review the current state of research and key issues on cell culture and implants, drug delivery systems with complex release profiles and specific action, and high efficiency and sensitivity biosensors with different biosensing mechanisms, all of them based on PAA. The biocompatibility, morphology of the surface, nanoestructural engineering in-depth, surface functionalization and coatings are discussed and analyzed in detail.

5

Measurement by load cells of impact force which a human body receivesby external force

51%

Ito Y. , Nemoto T. , Ogura T. , Yamasita H. , Yanai S. , Matsuura H.

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2008

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tom Vol. 28, nr 1

39-42

EN

Purpose: By development of a robotics technique, the assisted living instruments which have intelligent functions are being developed. As a result, there is a possibility that the accident to which the assisted living instrument under actuation contacts a human body may occur. The purpose of this research is for the impact force measurement system which with load cells to build, and to evaluate performance. Design/methodology/approach: The impact force measurement system was built by load cells and a data logger. Evaluation of the performance of the system was carried out to static loads and dynamic loads. Findings: By covering the sensor part of load cells with shock absorbing material, it turned out that it is possible to measure impact load simple. Moreover, as a result of comparing the characteristic of shock absorbing material, it became clear that the impact-absorbing characteristic of cell sponge and organism soft tissue is in agreement. Research limitations/implications: This research estimated the impact-absorbing characteristic of organism soft tissue for the skin, fat, muscles, etc. as a complex. Practical implications: This paper cleared that the load which a bone receives by dynamic external force can be easily measured by load cells. Originality/value: The objective of this research project was to develop the system by which impact force is measured and evaluated based on the damage which a human body receives. And we were able to complete the prototype.