Introduction. Acrylic resin is a basic material used in preparation of partial and complete dentures. One of the methods of improving mechanical properties of removable dentures is reinforcing acrylic resin with artificial fibers. Aim of the study. To compare mechanical properties of acrylic material reinforced with various types of glass fibers. Material and method. Heat-cured Estetic acrylic resin by Wiedent was used for denture bases. Glass mat, fiberglass fabric, long glass fibers and short glass fibers were used as reinforcing phase of the acrylic resin. In total, forty specimens were prepared, of which eight samples were controls. Research samples consisted of four groups of eight specimens each. Mechanical examinations in three-point bending test were conducted by means of the Zwick 1435 universal testing machine. Results. Specimens reinforced with short glass fibers achieved the highest values of maximum bending force (105.7 ± 8.9 N). It corresponded to the highest values of bending strength (126.8 ± 10.7 MPa). The lowest strength was found for specimens reinforced with glass mat (82.8 ± 11.8 MPa). The highest value of Young’s modulus was obtained for the samples reinforced with fiberglass fabric (3.7 ± 0.8 GPa). The highest values of deflection at maximum bending force were found for the samples reinforced with long glass fibers (4.0 ± 0.6 mm). Conclusions. The highest bending strength parameters were found for specimens reinforced with short and long glass fibers. Short glass fibers are better at improving mechanical properties of acrylic resin than long glass fibers.

Si³a oecinaj¹ca zrywaj¹ca po³¹czenie wybranych polimerów ze szkliwem zêba mlecznego po ekspozycji na ozon Streszczenie -W warunkach dooewiadczalnych porównano wielkooeci si³y oecinaj¹cej, zrywaj¹cej po³¹czenie ze szkliwem zêba, poddanego lub niepoddanego ozonowaniu, polimerowych materia-³ów ³¹cz¹cych (XP Bond i Xeno III), zastosowanych z polimerem wype³niaj¹cym Dyract Extra. W badaniu wykorzystano 90 zêbów trzonowych mlecznych. Po oczyszczeniu powierzchni szkliwa 60 próbek poddano dzia³aniu ozonu (w tym 30 pokryto oerodkiem stymuluj¹cym remineralizacjê, uwalniaj¹cym jony F -), a wybrane polimerowe materia³y ³¹cz¹ce zastosowano zgodnie z instrukcj¹ producenta. Nastêpnie, na tak przygotowan¹ powierzchniê zêba nak³adano polimer wype³niaj¹cy Dyract Extra. Zmierzon¹ si³ê oecinaj¹c¹ przeliczono na powierzchniê kontaktu materia³u polimerowego ze szkliwem wyznaczaj¹c wartooeae si³y adhezji dla ka¿dej próbki. Zaobserwowano, ¿e ozonowanie szkliwa zêba mlecznego mo¿e w znacznym stopniu zwiêkszyae si³ê wi¹zania polimerów do jego powierzchni, natomiast zastosowanie po ozonowaniu oerodka stymuluj¹cego remineralizacjê zmniejsza wartooeae tej si³y. S³owa kluczowe: adhezja, polimery ³¹cz¹ce i wype³niaj¹ce, szkliwo zêba, ozon. SHEARING FORCE BREAKING THE CONNECTION OF SELECTED POLYMERS WITH DECI-DUOUS TOOTH ENAMEL AFTER THE EXPOSURE TO OZONESummary -The aim of this experimental examination was to compare the values of shearing force, which breaks the connection between polymer bonding agents (XP Bond and Xeno III), used with restorative polymer Dyract Extra, and enamel, after and without enamel's exposure to ozone. Ninety deciduous molars extracted for orthodontic reasons were used in the study. After cleaning the enamel surface, sixty samples were subjected to ozone treatment (among them thirty teeth were covered with a remineralisation agent releasing F -) (Fig. 1-3) and selected polymeric bonding agents were used according to the manufacturer's instructions (Table 1). Prepared in this way, enamel was covered with Dyract Extra polymeric restorative material. The measured shearing force was calculated per contact surface of the material and enamel. As a result the value of adhesive strength was calculated for every sample. It was observed that ozonating the deciduous tooth's enamel can significantly increase the adhesion of polymers to its surface, whereas the application of a remineralisation agent after the ozonating decreases the value of the adhesive strength (Table 2).

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Although the phenomenon of otoacoustic emission has been known for nearly 30 years, it has not been fully explained yet. One kind of otoacoustic emission is distortion product of the otoacoustic emission (DPOAE). New aspects of this phenomenon are constantly discovered and attempts are made to interpret correctly the obtained results. This paper discusses a new method of measuring DPOAE signals based on double phase-sensitive detection, which makes possible a real-time measurement of the DPOAE signal amplitude and phase. The method was applied for measurements of DPOAE signals in guinea pigs. Sample records are presented and the obtained results are discussed.

Strength parameters of dental photopolymer reinforced with long glass and aramid as well as aramid-glass hybrid fibers was to comparison. Static strength tests of 40 light-curing composite specimens were performed with the use of Zwick 1435 testing machine and testXpert V.8.1 software. Flexural strength of aramid fiber reinforced polymer increased nearly three times, whereas flexural strength of polymer reinforced with glass fiber-twice.

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The purpose of the study was the comparison of poly(methyl methacrylate) reinforced with different types of long fibers: glass, carbon, aramid, glass-aramid hybrid and carbon-aramid hybrid fibers. The test material included 48 samples in the form of a cuboid. The strength tests were performed using the Zwick 1435 machine. The highest strength increase in relation to control samples was obtained with the use of aramid fibers and the lowest with the use of glass fibers.

The oral absorption of many drugs is highly influenced by intestinal biotransformation. To characterize or even predict the impact of intestinal drug processing, the knowledge of intestinal expression levels of enzymes is an essential prerequisite. Therefore, the aim of this study was to comprehensively analyse the expression of clinically relevant phase I and II enzymes, and nuclear receptors along the entire human gastrointestinal tract. Intestinal tissue was collected from 8 organ donors (age: 24-56). In each case 10 samples from the entire gut (duodenum: 1, jejunum: 2, ileum: 3, colon: 4) were taken, and mRNA expression of 12 genes of metabolizing enzymes (CYPs: 8, phase II enzymes: 4) were measured using custom-made TaqMan 1 low density arrays. Gene expression was normalized to five house-keeping genes and analyzed using the DDCt-method. Intestinal expression of CYP2C9, CYP2D6, SULT1A, UGT1A and UGT2B7 increased from duodenum to jejunum and was the highest in distal jejunum but markedly lower in ileum and colon. CYP3A4/5 was predominately found in the upper intestine. The intestinal expression rang order of drug metabolizing enzymes was as follows: CYP3A4 > CYP2C9 > CYP2C19 > CYP2D6 = CYP3A5 = CYP2B6, CYP2C8. In all intestinal regions, SULT1A, UGT1A, CYP3A4 and CYP2C9 were the most prominent genes. The intestinal distribution of the expression of SULT1A and UGT1A enzymes and UGT2B7 was as follows: duodenum < jejunum > ileum > colon, whereas for UGT2B15 there was stable but significantly lower expression along GI tract. There is a substantial expression gradient for several enzymes along the human alimentary tract, which may explain regio-selective differences in intestinal drug metabolism.http://dx.Recently the efficacy of alpha-lipoic acid (ALA) on atherosclerosis was suggested, by showing that ALA modulates multiple pathogenic aspects of atherosclerosis. The aim of the study was to http://dx.