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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Plačiajuostės dielektrinės spektroskopijos metodų tobulinimas, tiriant (1-x)(Na1/2 Bi1/2)TiO3 - xLa(Mg1/2 Ti1/2)O3 ir kitas medžiagas / Development of the methods of broadband dielectric spectroscopy by investigating (1-x)(Na1/2 Bi1/2)TiO3 - xLa(Mg1/2 Ti1/2)O3 and other materials

Rudys, Saulius 01 October 2012 (has links)
Šiame darbe nagrinėjamos galimybės patobulinti plačiajuostės dielektrinės spektroskopijos metodus naudojant skaitmeninius ir analitinius daugelio modų dielektrinės skvarbos skaičiavimo metodus, tiriami (1-x)(Na1/2 Bi1/2)TiO3 - xLa(Mg1/2 Ti1/2)O3 (NBT-LMT) keramikų grupės laidumo ypatumai. Nagrinėjama galimybė pritaikyti HFSS skaitmeninio modeliavimo programą dielektrinės spektroskopijos tikslams. Naudojant šią programinę įrangą, apskaičiuojama dielektrinė ir magnetinė skvarbos komplikuotiems mikrojuostelinės linijos ir dalinai užpildyto bangolaidžio matavimo grandinių atvejams. Pateikiami patobulinti kondensatoriaus koaksialinėje linijoje ir ribotų matmenų atviro galo koaksialinės linijos matematiniai modeliai. Šie modeliai patikrinami skaitmeniniu metodu. Naudojant daugiamodį kondensatoriaus modelį, atsižvelgus į magnetinio lauko pasiskirstymą koaksialinėje matavimo grandinėje, pasiūlomas būdas pamatuoti mažai bandinio magnetinei skvarbai, kai dielektrinė skvarba didelė (dešimtim ar šimtais kartų didesnė už magnetinę skvarbą). Atviro galo koaksialinei linijai siūloma keletas kalibravimo būdų, įrenginys bandiniui prispausti prie linijos. Bešvinė NBT-LMT keramika buvo tyrinėjama dielektrinės spektroskopijos metodais. Gauti rezultatai rodo, kad NBT-LMT keramikų grupėje elektriniam laidumui galioja Maerio-Neldelio taisyklė. / One of the basic problems in measurements of the electrical properties of materials is finding relations between measured electrical values and characteristics of the material, especially when the field distribution in the device under test with a sample inside is complex. Commercial electromagnetic simulation software was used in unconventional way to calculate materials' electrical properties. Because the software is not adopted for this task, built-in optimisation option was used. In this way dielectric and magnetic properties of materials in very complex shape were calculated. The method was tested by calculation of complex dielectric permittivity of Bi1.5ZnNb1.5O7-xF2 pyrochlore ceramics as well as by calculation of both complex dielectric permittivity and complex dielectric permeability of carbon-coated capsules of Ni embedded into polyurethane matrix from experimental results. Due to the fact that using numerical methods is time consuming, a mathematical model on mode matching approach of rectangular rod in a waveguide and a new model of multimode capacitor were developed. Models were checked by numerical methods. On a high frequency, when electric field in the sample is inhomogeneous, the magnetic field in the sample is much stronger than in the transmission line. Thus, the magnetic permeability of the sample will affect scattering parameters. Based on this circumstance, the method to measure small magnetic permeability using capacitor like in coaxial line when... [to full text]
32

Uticaj tehnoloških faktora u proizvodnji crvenih vina na sadržaj i stabilnost katehina i njihovih oligomera / Influence of technological factors in the production of red wine on the content and stability of catechins and their oligomers

Puškaš Vladimir 13 July 2010 (has links)
<p>Fenolna jedinjenja su zaslužna za<br />osnovna senzorna svojstva srvenih vina,<br />pre svega boju i trpkost. Superoksid (O2<sup>&bull;-</sup>) i hidroksil radikali (<sup>&bull;</sup>OH) izazivaju<br />ozbiljna o&scaron;tećenja tkiva degradaciju<br />proteina, nerastvornih lipida, ugljenih<br />hidrata i nukleinskih kiselina. U ovom<br />radu ispitan je uticaj tehničkotehnolo&scaron;kih<br />uslova proizvodnje i odnosa<br />čvrste i tečne faze u kljuku, na boju vina,<br />sadržaj fenolnih jedinjenja i<br />antioksidativni potencijal. Izmena odnosa<br />čvrste i tečne faze u kljuku vr&scaron;ena je<br />vraćanjem jednog dela ili celokupne<br />količine &scaron;epurine i povećavanjem<br />sadržaja semenki dodavanjem 100, 200 i<br />300 % semenki u odnosu na prirodni<br />sadržaj. Stabilnost boje, sadržaja fenolnih<br />jedinjenja i antioksidativnog potencijala<br />ispitivana je pre i nakon tretmana vina sa<br />dva organska i dva neorganska sredstva<br />za bistrenje i stabilizaciju. Utvrđeno je da<br />povećanje sadržaja semenki u kljuku<br />pojačava antioksidatovno delovanje vina.<br />U vinu Cabernet sauvignon utvrđena je<br />vi&scaron;a vrednost antiradikalske aktivnosti<br />prema DPPH radikalima (AA<sub>(DPPH&bull;)</sub>),<br />koja se nije promenila pod delovanjem<br />sredstava za bistrenje i stabilizaciju vina.<br />Vino Merlot ispoljilo je veću<br />antiradikalsku aktivnost na hidroksil<br />radikale (AA<sub>(&bull;OH)</sub>).</p> / <p>Phenolic compounds are responsible for<br />basic sensory properties of red wines,<br />primarily color and astrigency.<br />Superoxide (O2<sup>&bull;-</sup>) and hydroxyl radicals<br />(<sup>&bull;</sup>OH) causes serious damage to the tissue<br />degradation of proteins, ansolubility<br />lipids, carbohydrates and nucleic acids.<br />The paper examined the impact of<br />technical and technological conditions of<br />production and relations of liquid and<br />solid phases in pomase on the color of<br />wine, phenolic compounds content and<br />antioxidant potential. Changing relations<br />between solid and liquid phases in<br />pomase carried out the return of a part, or<br />the whole amount of stem and increasing<br />seeds content adding +100, +200 and<br />+300 % of seeds. Color stability,<br />phenolic compounds content and<br />antioxidative potential was examined<br />before and after treatment of wine with<br />two organic and two inorganic agens for<br />fining and stabilization. It was found that<br />increasing the seeds content in pomase<br />increases antioxidative action of wines.<br />In the wine Cabernet Sauvignon was<br />found higher value antiradical activity to<br />DPPH radicals (AA<sub>(DPPH&bull;)</sub>), which are not<br />changed under the fining action and<br />stabilization of wine. Merlot wine<br />exhibited a higher antioxidant potential<br />of the hydroxyl radicals (AA<sub>(&bull;OH)</sub>).</p>
33

Dobijanje lantan-galata za primenu u gorivnim ćelijama / Obtaining of lanthanum-gallate for fuel cells application

Stijepović Ivan 28 December 2012 (has links)
<p>U ovom radu su sintetisani prahovi na bazi lantan-galata, citratnom sol-gel<br />metodom i hemijskom sintezom u parnoj fazi (CVS), a njihovim presovanjem<br />i sinterovanjem su dobijeni keramički uzorci kontrolisane mikrostrukture. Cilj<br />disertacije je bio dobijanje guste keramike koja bi mogla da se primeni kao<br />jonski provodni elektrolit u gorivnim ćelijama sa čvrstim elektrolitom (SOFC),<br />a koje bi radile na srednjim temperaturama od 500&ndash;700 &deg;C (IT-SOFC). Po prvi<br />put su sintetisani nanoprahovi lantan-galata u gasnoj fazi i utvrđeno je da ovako<br />dobijeni polazni prahovi, zbog svojih superiornih karakteristika omogućavaju<br />snižavanje temperature sinterovanja za 150 &deg;C, &scaron;to je veoma povoljno kako sa<br />stanovi&scaron;ta dizajniranja mikrostrukture, tako i zbog u&scaron;tede energije u procesu<br />proizvodnje gorivnih ćelija. Ipak, zbog nedovoljne kontrole hemijskog sastava<br />i stehiometrije sintetisanih prahova, &scaron;to je i najveći nedostatak CVS metode<br />dobijanja perovskitnog LaGaO<sub>3</sub>, nije bilo moguće dobiti keramiku koja bi ispunjavala zahteve za primenu u SOFC. S druge strane, citratna sol-gel metoda<br />pruža veliku kontrolu pomenutih parametara zbog čega je bila moguća sinteza<br />čitavog niza čvrstih rastvora lantan-galata. Ovom metodom su tako sintetisani<br />čist lantan-galat (LG) i dopirani prahovi kod kojih je deo lantana supstituisan<br />stroncijumom, a deo galijuma magnezijumom: La<sub>0,85</sub>Sr<sub>0,15</sub>Ga<sub>0,85</sub>Mg<sub>0,15</sub>O<sub>3-</sub><br />La<sub>1-x</sub>Sr<sub>x</sub>Ga<sub>0,8</sub>Mg<sub>0,2</sub>O<sub>3-</sub>, gde je x = 0,10, 0,15 ili 0,20 (LSGM). Svi ovako sintetisani</p><p>prahovi su zahtevali naknadnu kalcinaciju na 900 &deg;C, ali su potrebne<br />gustine (&gt;95% teorijske gustine) postignute sinterovanjem na temperaturi<br />od 1450 &deg;C već nakon 2 h, &scaron;to je izuzetno kratko imajući u vidu literaturne<br />podatke. Takođe, sinterovani uzorci su po faznom sastavu bili čista LSGM<br />keramika, a impedansna merenja su pokazala da je najveću provodljivost imao<br />uzorak La<sub>0,85</sub>Sr<sub>0,15</sub>Ga<sub>0,8</sub>Mg<sub>0,2</sub>O<sub>3-</sub>. Ovaj sastav je dalje kori&scaron;ćen u cilju provere</p><p>mogućnosti za dodatno povećanje provodljivosti te su pripremljeni i uzorci kod kojih je izvr&scaron;ena parcijalna supstitucija magnezijuma sa niklom ili kobaltom:<br />La<sub>0,85</sub>Sr<sub>0,15</sub>Ga<sub>0,8</sub>Mg<sub>0,2-y</sub>MyO<sub>3-</sub>, gde je M = Ni ili Co, a y = 0,03 ili 0,05 (LSGMN i</p><p>LSGMC). Pokazano je da dodatak male količine prelaznih metala značajno utiče<br />na mehanizam provođenja, ali da je na vi&scaron;im temperaturama jonska provodljivost<br />i dalje dominantna. Konstatovano je da se dodavanjem male količine Ni ili Co u<br />LSGM mogu dobiti materijali koji bi služili kao elektroliti u IT-SOFC, pri čemu je<br />potencijal nikla kao dopanta ne&scaron;to veći nego kobalta.</p> / <p>Powders based on lanthanum-gallate have been synthesised in this work by using citrate sol-gel method in the liquid phase and by chemical vapour synthesis (CVS). As-synthesised powders were calcined, pressed and finally sintered in order to produce ceramic samples with controlled microstructure. The main goal of this dissertation has been obtaining of dense ceramics for application in ion conducting electrolyte for solid oxide fuel cells working at 500&ndash;700 &deg;C (IT-SOFC). Lanthanum-gallate nanopowders have been synthesised in the gas phase for the first time and it has been determined that these starting powders posses superior properties which could lower down the sintering temperature for about 150 &deg;C. This is very significant considering microstructure design, but also high energy consumption during the manufacturing process of fuel cells. However, it has not been possible to obtain ceramics with exact properties needed for SOFC application using CVS due to the lack of control of chemical composition and stoichiometry of the as-synthesised powders, which are the main drawbacks of this method. On the other hand, citrate sol-gel method offered a possibility to precisely control aforementioned parameters which enabled synthesis of a whole range of lanthanum-gallate sollid solutions. So, pure perovskite lanthanum-gallate (LG) has been synthesised by using this liquid phase method, but also doped powders where part of lanthanum and gallium was supstituted with strontium and magnesium, respectively: La<sub>0,85</sub>Sr<sub>0,15</sub>Ga<sub>0,8</sub>5Mg<sub>0,15</sub>O<sub>3- </sub>and La<sub>1-x</sub>Sr<sub>x</sub>Ga<sub>0,8</sub>Mg<sub>0,2</sub>O<sub>3-</sub>, where x = 0.10, 0.15 or 0.20 (LSGM). Calcination at 900 &deg;C was necessary step during the processing of these sol-gel powders but the sintering time at 1450 &deg;C was only 2 h which is quite short in comparison with available literature data. Additionaly, the sintered samples were phase pure LSGM ceramics and impedance measurement showed that the highest conductivity had sample La<sub>0,85</sub>Sr<sub>0,15</sub>Ga<sub>0,8</sub>Mg<sub>0,2</sub>O<sub>3-</sub>. Accordingly, this composition has been used to check the possibility of further improvement of conductivity. A set of new samples has been prepared where one part of magnesium has been substituted with nickel or cobalt: La<sub>0,8</sub>5Sr<sub>0,1</sub>5Ga<sub>0,8</sub>Mg<sub>0,2-y</sub>MyO<sub>3-</sub>, where M = Ni or Co and y = 0.03 or 0.05 (LSGMN i LSGMC). It has been shown that addition of small amount of transition metals significantly influences conduction mechanism, but at higher temperatures the ionic conductivity is still dominant. It has been found that electrolyte materials for IT-SOFCs could be obtained by incorporation of small quantities of Ni or Co into LSGM and that nickel is more promissing for this purpose than cobalt.</p>
34

Fotoluminescencija i Ramanova spektroskopija specifičnih kompleksnih organometalnih jedinjenja na bazi cinka, kobalta i bakra pogodnih za primenu u organskim svetlećim diodama / Photoluminescence and Raman spectroscopy of specific complexcompounds based on zinc, cobalt and copper suitable for application inorganic light emitting diodes

Jelić Miodrag 30 May 2017 (has links)
<p>U okviru doktorske disertacije predstavljene su elektronska i fononska struktura odabranih organometalnih materijala koji u svom sastavu imaju metale cink, kobalt ili bakar i organsko jedinjenje piridoksalaminogvanidin (PLAG). Predstavljene su realizacija i karakteristike organske svetleće diode zasnovane na najboljem od ispitivanih materijala. Urađena je detaljna analiza fotoluminescentnih spektara i njihovo razlaganje na proste komponente koristeći Lorencov model. Izvršeno je poređenje sa od ranije poznatim materijalom koji pokazuje visok stepen luminescencije. S obzirom da istraživanja vezana za organske svetleće diode uzimaju sve veći zamah i da ove diode postaju sve prisutnije u industrijskoj serijskoj proizvodnji, napravljena je detaljna analiza ove tehnologije i mehanizama koji se kriju iza nje. Urađeno je podrobno istraživanje kako na nivou elektrona u datim supstancama, tako i na nivou sloja organske svetleće diode. Na kraju je izvršena analiza rada diode sa integrisanim slojem sa materijalom koji u sebi sadrži cink i PLAG.</p> / <p>In this thesis electronic and phonon structure of specific organometallic<br />materials which have zinc, cobalt, copper metals and organic compound<br />pyridoxalaminoguanidin are presented. Implementation and characteristics of<br />organic light emitting diode based on the best material among examined<br />ones are also showed up. Detailed analysis of photoluminescence spectra<br />was done and its decomposition to its elementar components using<br />Lorentzian multipeak method. Comparison to well-known material that shows<br />high level of luminescence was implemented. In accordance to the fact that<br />research of organic light emitting diodes expands and that these diodes start<br />to be more present in industrial serial production, detailed analysis of this<br />technology and mechanisms behind it are made. Thorough research was<br />done both on electron level in these substances and organic light emitting<br />diode layer level. Finally, analysis of diode operation with integrated layer<br />made of material which includes zinc and pyridoxalaminoguanidin compound<br />is implemented.</p>
35

Antioksidanti u zrnu soje i njegovim proizvodima / Antioxidants in soybean grain and soybean products

Sakač Marijana 21 July 2000 (has links)
<p><strong>Apstrakt je obrađen tehnologijama za optičko prepoznavanje teksta (OCR).</strong></p><p>Ispitan je uticaj heksanskih, etanolnih i etil-acetanih ekstrakata zrna soje i punomasnih hraniva od zrna soje, ekstrudiranog sojinog griza i hidrotermički tretiranog zrna soje, na termičku i katalitičku oksidaciju metil-linoleata primenom ESR spektroskopije i &quot;spin- traping&quot; tehnike. Utvrđeno je da ispitivani ekstrakti inhibiraju termičku i katalitičku oksidaciju metil-linoleata različitim mehanizmima antioksidativnog delovanja. Ustanovljeni antioksidativni efekti dovedeni su u vezu sa vrstama i sadržajem liposolubilnih (a-tokoferol, P-karotin, ukupni ksantofili) i neliposolubilnih antioksidanata (izoflavoni i fitinska kiselina) soje, odnosno u vezu sa termičkim tretmanima primenjenim u proizvodnji ovih hraniva. Ispitani su i uticaji primene različitih rastvarača (etil-acetat, etanol, acetonitril) na antioksidativne efekte ekstrakata neliposolubilnih antioksidanata punomasnih hraniva od zrna soje tokom termičke i katalitičke oksidacije sojinog ulja primenom ESR.</p> / <p><strong>Abstract was processed by technology for Optical character recognition (OCR).</strong></p><p>The influence of hexane, ethanol and ethyl acetate extracts of soybean grain and full-fat feeds of soybean grain, fullfat extruded soybean grits and hydrothermal treated soybean grain on the thermal and catalytic oxidation of methyl linoleate has been studied by ESR spectroscopy and spin-trapping method. It has been found that the investigated extracts inhibit the thermal and catalytic oxidation of methyl linoleate through different mechanisms of antioxidation action. The antioxidative effects found were related to the kinds and contents of soybean liposolubile (a-tocopherol, P-carotene, total xanthophyls) and nonliposolibile antioxidants (isoflavones, phytic acid), that is, they were put in relation to thermal treatments used in production of these feeds. The effects of the application of different solvents on the antioxidative actions of the extracts of nonliposolubile antioxidants of full-fat soybean feeds during thermal and catalytic oxidation of soybean oil have been studied by ESR.</p>
36

Uticaj žučnih kiselina na bioraspoloživost makrolidnih antibiotika / The effects of bile acids on macrolide antibiotics bioavailability

Trifunović Jovana 13 May 2016 (has links)
<p>Uvod: U pro&scaron;losti žučne kiseline su uglavnom razmatrane sa stanovi&scaron;ta njihove funkcije koju obavljaju u crevima jer posreduju u varenju masti i apsorpciji liposolubilnih vitamina. Nedavne studije potvrđuju da žučne kiseline ne igraju samo ulogu u varenju masti, nego se pona&scaron;aju i kao signalni molekuli koji stupaju u interakciju sa raznim receptorima uključujući nuklearne receptore i receptore vezane za G-proteine. Kao amfipatični molekuli one su sposobne da reaguju sa fosfolipidima ćelijskih membrana i da pobolj&scaron;avaju prolazak lekova kroz njih. Stoga se žučne kiseline razmatraju kao promoteri u bukalnim, okularnim i nazalnim farmaceutskim formulacijama. Cilj: Svrha ovog istraživanja je bila da se ispitaju žučne kiseline i njihovi okso derivati kao jedinjenja koja utiču na propustljivost ćelijskih membrana i prolazak lekova do ciljnih tkiva. Materijal i metod: Interakcije makrolidnih antibiotika i žučnih kiselina su ispitivane uz pomoć NMR difuzionih merenja i relaksacije paramagnetičnim jonima. Retencioni parametri odabranih žučnih kiselina su dobijeni kori&scaron;ćenjem hromatografije na normalnim fazama i evaluisani su primenom pet različitih softvera. In vivo ekaperimenti su sprovedeni na 126 eksperimentalnih životinja koje su bile podeljene u 21 grupu. Rezultati: Vezivanje žučnih kiselina za micele je indikovano razlikama u hemijskom pomeranju makrolida i pro&scaron;irenju signala kao posledica redukovane mobilnosti unutar micela. Dodatak micela žučnih kiselina povećava solubilizaciju makrolida za faktor približno 2-3. Sprovedena korelaciona analiza pokazala je značajnu zavisnost između faktora retencije i intestinalne apsorpcije, prodora u MDCK epitelne ćelije, permeabilnost kroz kožu, logBB i PPB%. Putem implementacije in vivo eksperimentalnog dela pokazano je da žučne kiseline utiču na prolazak makrolida u tkivo mozga, bubrega i jetre. Zaključak: Ispitivane žučne kiseline pokazuju dobre farmakokinetske karakteristike i olak&scaron;avaju prolazak makrolida kroz različite ćelijske membrane.</p> / <p>Introduction: In the past, bile acids were mostly considered to function in the intestine where they play a role in digestion of fats and mediate absorption of fat-soluble vitamins. Recent studies confirm that bile acids not only facilitate solubilization of fats but behave as signal molecules that interact with various receptors including nuclear receptors and G protein-coupled receptors. As amphipathic molecules they are able to interact with phospholipids of cells membranes and enhance drugs permeation. Thus, bile acids are considered as drug promoters in buccal, ocular, nasal, and transdermal dosage forms. Purpose: The purpose of this research was to investigate bile acids and its oxo derivatives as enhancers in drug permeability. Three research methods to evaluate the characteristics of bile acids and its properties were used. Material and method: The interaction between macrolide antibiotics and bile acids was investigated by NMR chemical-shift titration, self-diffusion measurements and paramagnetic relaxation enhancements. Retention parameters of selected bile acids are acquired by normal-phase thin layer chromatography and evaluated using five different softwares. In vivo experiments were conducted on 126 animals which were divided in 21 groups. Results: Binding bile acids to the micelles is indicated by differences in the chemical shift of the macrolides and line broadening as a consequence of reduced mobility in the micelle. Addition of bile micelles increases the solubility of macrolide antibiotics by a factor of approximately 2&ndash;3. Examined correlation analysis confirmed significant dependence between retention factor and intestinal absorption, MDCK epithelial cells, skin permeability, logBB and PPB%. Through the implementation of in vivo experiments it is shown that bile acids promote penetration of macrolides in brain tissue, kidney and liver. Conclusion: Investigated bile acids showed good pharmacokinetic properties and facilitate in macrolides permeation through various membranes.</p>
37

Dijagnostički značaj i pouzdanost stereotaksične biopsije u tretmanu pacijenata sa tumorima mozga / Diagnostic value and reliability of stereotactic biopsy in treatment of patients with brain tumors

Jelača Bojan 14 September 2018 (has links)
<p>Uvod: Implementacija brojnih neuroradiolo&scaron;kih modaliteta je značajno uticala na način i efikasnost sprovođenja dijagnostike tumora mozga. Na osnovu neinvazivno dobijenih podataka može se postaviti diferencijalna dijagnoza, ali do sada nije potvrđena nijedna neuroradiolo&scaron;ka metoda koja može samostalno i konačno da postavi definitivnu patohistolo&scaron;ku (PH) dijagnozu. Stereotaksična biopsija je neurohirur&scaron;ka procedura kojom se, bez bitnog naru&scaron;avanja integriteta i funkcije moždanog tkiva, može obezbediti reprezentativni uzorak intrakranijalne tumorske promene radi sprovođenja PH i drugih specifičnih analiza, u cilju postavljanja tačne dijagnoze i potom primene adekvatnog lečenja. Cilj: Cilj ove studije je da se utvrditi mogućnost uzorkovanja reprezentativnog tkiva za postavljanje PH dijagnoze uz pomoć stereotaksične biopsije kod pacijenata sa tumorom mozga, kao i da se utvrdi vrsta i učestalost eventualnih komplikacija same procedure i postojanje korelacije između PH nalaza dobijenog stereotaksičnom biopsijom i rezultata sprovedenih neuroradiolo&scaron;kih ispitivanja. Materijal i metode: Sprovedeno istraživanje je bilo kliničko, prospektivno, a uzorak je činilo ukupno 50 pacijenata koji su bili hospitalizovani na Klinici za neurohirurgiju KCV zbog dijagnostikovane tumorske promene mozga i postavljene indikacije za stereotaksičnu biopsiju, u periodu od septembra 2016. godine do januara 2018. godine. Svi pacijenti koji su uključeni u studiju su u sklopu sprovedene dijagnostičke obrade imali načinjen magnetno rezonanantni (MRI) pregled glave na osnovu kojeg su se određivale morfolo&scaron;ke karakteristike tumora i vr&scaron;ila procena prirode tumorske promene mozga, a kod ukupno 25 pacijenata je dodatno načinjena MR spektroskopija (MRS) dijagnostikovane tumorske promene sa ciljem određivanja biohemijskog profila i dodatne procene i karakterizacije tkiva. Nakon sprovedene detaljne onkolo&scaron;ke obrade i adekvatne pripreme, se sprovodila kompjuterizovanom tomografijom (CT) navođena stereotaksična biopsija sa ramom u cilju uzorkovanja adekvatnog tkiva za PH analizu. U toku istraživanja procena uspe&scaron;nosti uzorkovanja reprezentativnog tkiva se vr&scaron;ila pregledom bioptata od strane patologa, a nakon procedure se kliničkim pregledom i kontrolnim CT pregledom glave utvrđivao stepen komplikacija. Rezultati: Dobijeni rezultati su pokazali da su fokalni neurolo&scaron;ki deficit i moždani sindrom bili najče&scaron;ći klinički simptomi i znaci kod pacijenata kod kojih je indikovana stereotaksična biopsija tumora mozga. Prema MRI nalazu najzastupljenije su bile difuzne tumorske promene sa 36% udela u uzorku, zatim solitarne sa 34% i multifokalne sa 20%, a potom multicentrične tumorske promene koje su predstavljale 10% uzorka. Takođe, na osnovu MRI i MRS nalaza je oko 80% tumora procenjeno kao najverovatnije glijalnog porekla. U 95,9% slučaja je postavljena precizna PH dijagnoza. Nepromenjeno stanje svesti i neurolo&scaron;ki nalaz su imali 92% pacijenata nakon biopsije, a kod 3 pacijenta (6%) je do&scaron;lo do razvoja prolaznog neurolo&scaron;kog deficita, dok je jedan pacijent (2%) razvio trajan neurolo&scaron;ki deficit. Ukupan morbiditet vezan za proceduru je stoga 2%, a nije zabeležen ni jedan smrtni slučaj (mortalitet 0%) tokom sprovođenja studije. Zaključak: Stereotaksična biopsija je dokazana i veoma pouzdana procedura sa malim brojem komplikacija i niskom stopom morbiditeta i mortaliteta, kojom se omogućava dobijanje reprezentativnog uzorka tumorskog tkiva za postavljanje sigurne patohistolo&scaron;ke dijagnoze. Intraoperativna PH analiza dela uzorka tkiva dodatno pobolj&scaron;ava uspe&scaron;nost pri uzorkovanju i postavljanju definitivne PH dijagnoze. Savremene neuroradiolo&scaron;ke metode imaju visoku specifičnost u razlikovanju biolo&scaron;ke prirode tumorskih promena, ali se ne mogu koristi nezavisno od PH analize uzorka tkiva</p> / <p><!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:TrackMoves/> <w:TrackFormatting/> <w:PunctuationKerning/> <w:ValidateAgainstSchemas/> <w:SaveIfXMLInvalid>false</w:SaveIfXMLInvalid> <w:IgnoreMixedContent>false</w:IgnoreMixedContent> <w:AlwaysShowPlaceholderText>false</w:AlwaysShowPlaceholderText> <w:DoNotPromoteQF/> <w:LidThemeOther>EN-US</w:LidThemeOther> <w:LidThemeAsian>X-NONE</w:LidThemeAsian> <w:LidThemeComplexScript>X-NONE</w:LidThemeComplexScript> <w:Compatibility> <w:BreakWrappedTables/> <w:SnapToGridInCell/> <w:WrapTextWithPunct/> <w:UseAsianBreakRules/> <w:DontGrowAutofit/> <w:SplitPgBreakAndParaMark/> <w:DontVertAlignCellWithSp/> <w:DontBreakConstrainedForcedTables/> <w:DontVertAlignInTxbx/> <w:Word11KerningPairs/> <w:CachedColBalance/> 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QFormat="true" Name="Subtle Emphasis"/> <w:LsdException Locked="false" Priority="21" SemiHidden="false" UnhideWhenUsed="false" QFormat="true" Name="Intense Emphasis"/> <w:LsdException Locked="false" Priority="31" SemiHidden="false" UnhideWhenUsed="false" QFormat="true" Name="Subtle Reference"/> <w:LsdException Locked="false" Priority="32" SemiHidden="false" UnhideWhenUsed="false" QFormat="true" Name="Intense Reference"/> <w:LsdException Locked="false" Priority="33" SemiHidden="false" UnhideWhenUsed="false" QFormat="true" Name="Book Title"/> <w:LsdException Locked="false" Priority="37" Name="Bibliography"/> <w:LsdException Locked="false" Priority="39" QFormat="true" Name="TOC Heading"/> </w:LatentStyles></xml><![endif]--><!--[if gte mso 10]><style> /* Style Definitions */ table.MsoNormalTable{mso-style-name:"Table Normal";mso-tstyle-rowband-size:0;mso-tstyle-colband-size:0;mso-style-noshow:yes;mso-style-priority:99;mso-style-qformat:yes;mso-style-parent:"";mso-padding-alt:0in 5.4pt 0in 5.4pt;mso-para-margin-top:0in;mso-para-margin-right:0in;mso-para-margin-bottom:10.0pt;mso-para-margin-left:0in;line-height:115%;mso-pagination:widow-orphan;font-size:11.0pt;font-family:"Calibri","sans-serif";mso-ascii-font-family:Calibri;mso-ascii-theme-font:minor-latin;mso-fareast-font-family:"Times New Roman";mso-fareast-theme-font:minor-fareast;mso-hansi-font-family:Calibri;mso-hansi-theme-font:minor-latin;mso-bidi-font-family:"Times New Roman";mso-bidi-theme-font:minor-bidi;}</style><![endif]-->Introduction: The implementation of numerous neuroradiological techniques has significantly influenced the way and the efficiency in which the diagnosis of brain tumor is established. Based on non-invasive imaging data, a differential diagnosis can be made, but no neuroradiological method has been established so far, which can finally make a definitive diagnosis. Stereotactic biopsy is a neurosurgical procedure that can provide a representative sample of any intracranial tumor in order to performe histopathological and other specific examinations, and to set the exact diagnosis and then apply adequate treatment, but without significantly impairing the integrity and function of brain tissue. Objective: The aim of this study is to determine the diagnostic value of stereotactic biopsy and ability of providing the representative tissue in order to establish a pathohistological diagnosis in patients with brain tumors. Also, the aim is to determine the type and frequency of possible complications of the procedure itself and the correlation between the pathohistological findings obtained and the results of the conducted neuroradiological examinations. Materials and methods: This research was clinical, prospective and included a total of 50 patients who were hospitalized at the Clinical Center of Vojvodina, from September 2016 to January 2018, due to diagnosed brain tumor for which the stereotactic biopsy is indicated. In all patients magnetic resonance (MRI) examination of the head was used to determine morphological characteristics and assesse the nature of the brain tumor tissue, and in a total of 25 patients MR spectroscopy was additionally made with the goal of determining the biochemical profile and additional tissue assessment and characterization. After detailed oncological assessment, completed laboratory and radiological diagnostics, a CT guided framebased stereotactic biopsy was performed for the purpose of sampling tumor tissue for pathohistological analysis. During the research, the success rate of biopsy in providing the representative tissue and establishing the diagnosis was performed by a pathologist, and after the procedure, a clinical and a control head CT examination was used to review the rate of complications. Results: The results obtained showed that focal neurological deficit and psychoorganic syndrome were the most common clinical symptoms and signs in this study. According to MRI, the most common were diffuse brain tumors with 36% of the sample, then solitary with 34% and multifocal with 20%, followed by multicentric tumors representing 10% of the study sample. Also, based on MRI and MRS findings, approximately 80% of tumors are estimated to be most likely of glial origin. In 95.9% of cases, a complete pathohistological (PH) diagnosis was established. The unchanged neurological status was observed in 92% of patients after biopsy, and 3 patients (6%) developed a transient neurological deficit, while only one patient (2%) developed a permanent neurological deficit. The total morbidity associated with the procedure is therefore 2%, and no deaths (mortality 0%) related to the procedure during the study is recorded. Conclusion: Stereotactic biopsy is highly reliable procedure with a small number of complications and a low morbidity and mortality rate, which allows us to acquire the representative sample of brain tumor tissue and to establish a pathohistological diagnosis. Intraoperative PH analysis of acquired tissue samples further enhances the sampling performance and the setting of definitive PH diagnosis. Modern neuroradiological modalities have a high specificity in distinguishing the biological nature of brain tumors, but they still can not be used independently of the pathohistological analysis of the tissue sample.</p>
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Aktivacija procesa sinterovanja kod silikatnih sistema promenom atmosfere pečenja / Activation of the sintering processes in silicate systems by changing the firing atmosphere

Rekecki Robert 27 January 2015 (has links)
<p>Proces pečenja u proizvodnji keramičkog crepa u većini slučajeva se izvodi u<br />oksidavionoj atmosferi. Dobijena mikrostruktura koja obezbeđuje najvažnije osobine<br />primene zavisi od mineralo&scaron;kog sastava polaznog materijala i temperature termičkog<br />tretmana.<br />Sa stanovi&scaron;ta proizvodnje glinenog crepa, sirovina sa značajnim sadržajem karbonata kao &scaron;to je kop gline u Kanjiži, predstavlja problem te se ne može koristiti u njenom prirodnom sastavu. U oksidacionom termičkom tretmanu, staklasta faza koja se formira razgradnjom lakotopivih glinenih minerala ne kvasi u dovoljnoj meri zemnoalkalne okside nastale razgradnjom karbonata. Očekivane nove kristalne faze, kao &scaron;to su gelenit i anortit, koje predstavljaju osnovu dobrih tehničkih osobina crepa, ne mogu nastati u potrebnoj količini. Jedno od re&scaron;enja ovog problema je pobolj&scaron;anje interakcije između silikata i CaO/MgO promenom kvaliteta atmosfere pečenja.<br />Cilj je bio da se dobije odgovor na pitanje, da li se mogu promenom tehnolo&scaron;kih<br />parametara pečenja pobolj&scaron;ati karakteristike finalnog proizvoda dobijenog od sirovinske sme&scaron;e sa visokim masenim udelom karbonata.<br />Dati su rezultati pečenja u oksidacionoj i redukcionoj atmosferi u pogledu fizičkomehaničkih karakteristika i nastanka novih kristalnih faza. U radu su primenjene metode 57Fe M&ouml;ssbauer spektroskopije, difrakcija X zraka i dilatometrijska analiza za<br />identifikaciju promena faza tokom pečenja u oksidacionoj i redukcionoj atmosferi<br />(CO/N2 atmosfera) na temperaturama od 700-1060&deg;C. Ove promene reflektuju<br />dehidroksilaciju glinenih minerala, dekompoziciju karbonata, denzifikaciju i formiranje<br />novih kristalnih faza (plagioklasi). U cilju analize industrijskih uzoraka, pored 57Fe<br />M&ouml;ssbauer spektroskopije, primenjene su i sledeće metode: skenirajuća elektronska<br />mikroskopija (SEM) sa EDS analizom, živina porozimetrija, fotoelektronska spektroskopija (XPS) i karakterizacija apsorbcije vode, otpornosti na mraz i nosivosti.<br />Primena redukujuće atmosfere pokazala se kao opravdana, dobijen je glineni crep<br />pobolj&scaron;anih karakteristika u odnosu na standardni proizvod pečen u oksidacionoj<br />atmosferi.</p> / <p>The firing process in clay roofing tile production is normally carried out in oxidizing<br />firing atmosphere. The obtained microstructure which provides the most important<br />properties of the application depends on the mineralogical composition of the starting raw material and the firing temperature.<br />Concerning the production of roofing tiles, clay raw materials with a high content of<br />carbonates such as the Kanjiza clay material, possess an inappropriate composition. The melt phase is formed after the decomposition of clay minerals during the common firing process. This liquid phase, due to its extent wetting characteristics, is not able to wet properly the earth alkali oxides obtained after the decomposition of the carbonates. The expected new crystalline phases, like gehlenite and anorthite, which are needed for the favorable technical properties of the roofing tiles, can not be formed in the required quality and quantity. One solution to this problem is the limebonding improvement by changing the conditions of the firing atmosphere.<br />The main aim of this work is to examine the effects of firing conditions on the<br />properties of clay roofing tiles with high carbonate content. The obtained physical and<br />mechanical properties and the obtained new crystalline phases are described in detail.<br />The experiment used dilatometry, X-ray diffractometry, 57Fe M&ouml;ssbauer<br />spectroscopy to identify the changes during the firing process in oxidizing and<br />reducing atmosphere (CO/N2 atmosphere) at temperatures between 700 and 1060&deg;C.<br />Furthermore, for industrial sample analysis, scanning electronmicroscopy with EDS,<br />XPS, Hg porosimetry, water absorption procedure, frost resistance and bending<br />measurements were applied.<br />The application of reducing atmosphere was proved to be valid. The obtained<br />roofing tiles had improved properties compared to the standard production which uses<br />oxidizing firing atmosphere.</p>
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Adsorbuotų ant metalo paviršiaus monosluoksnių su piridinio funkcine grupe struktūros ir sąveikos su tirpalo komponentais tyrimas virpesinės spektroskopijos metodais / Vibrational spectroscopic study on the structure and interaction with solution components of monolayers with pyridinium functional group adsorbed on metal surface

Matulaitienė, Ieva 06 January 2014 (has links)
Savitvarkiai monosluoksniai suteikia metalų paviršiams norimas savybes ir plačiai taikomi elektronų pernašos tyrimuose, konstruojant (bio)jutiklius, biotechnologinius bei fotoelektroninius procesus. Teigiamo krūvio monosluoksniai naudojami kuriant anijonų jutiklius ir (bio)technologinius procesus su adsorbuotomis neigiamo krūvio makromolekulėmis. Darbe buvo susintetinta bifunkcinė molekulė su galinėmis tiolio ir piridinio grupėmis, suformuotas monosluoksnis ir ištirtos jo struktūrinės ir funkcinės savybės. Pagrindiniai darbo tikslai buvo ištirti N-(6-merkapto)heksilpiridinio (MHP) adsorbuoto ant Au ir Ag elektrodų struktūrą ir nustatyti monosluoksnio sąveikos su neorganiniais anijonais, dodecilsulfato anijonu ir grafeno oksidu dėsningumus. Naudojant paviršiaus sustiprintos Ramano spektroskopijos, kvantų chemijos skaičiavimo ir izotopinio pakeitimo metodus nustatyti MHP struktūros ir orientacijos elektrodo atžvilgiu Ramano sklaidos žymenys. Tiriant juostų intensyvumo priklausomybes nuo potencialo ir žadinančios spinduliuotės bangos ilgio parodyta, kad Au/MHP sistemoje pasireiškia krūvio pernešimo Ramano spektrų stiprinimo mechanizmas. Nustatyta, kad adsorbuotų neorganinių anijonų pilnai simetrinio virpesio dažnis sumažėja lyginant su tirpalo spektru ir tas pokytis koreliuoja su Gibso dehidracijos energija. Parodyta, kad MHP pritraukia grafeno oksidą. Nustatyta, kad grafeno oksido C-C ryšio ilgis ir elektroninė struktūra gali būti keičiama, keičiant potencialą. / Self-assembled monolayers provide possibility of changing metal surface properties in controllable manner and are widely used in studies of electron transfer, construction of (bio)sensors, and biotechnological and photoelectronic processes. Positively charged monolayers are valuable in development of sensors for anions and (bio)technological processes with adsorbed negatively charged macromolecules. In this work the structural and functional properties of monolayer formed from synthesized molecule with terminal thiol and pyridinium groups have been studied. The main tasks were to assess the structure of N-(6-mercapto)hexylpyridinium (MHP) on Ag and Au electrodes, and to determine the peculiarities of interaction with inorganic anions, dodecylsulfate, and graphene oxide. Based on surface enhanced Raman spectroscopy (SERS), quantum chemical calculations, and isotopic substitution studies, the Raman marker bands for structure and orientation of MHP have been evaluated. Dependence of SERS intensity on potential and excitation wavelength has revealed the operation of charge transfer Raman enhancement mechanism. It was found that the frequency of symmetric stretching mode of adsorbed ions decreases comparing with solution value and the extent of the shift correlates with the Gibbs dehydration energy. Adsorption of graphene oxide at MHP monolayer has been demonstrated. The electronic structure and length of C-C bonds of graphene oxide was found to be altered by the potential.
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Vibrational spectroscopic study on the structure and interaction with solution components of monolayers with pyridinium functional group adsorbed on metal surface / Adsorbuotų ant metalo paviršiaus monosluoksnių su piridinio funkcine grupe struktūros ir sąveikos su tirpalo komponentais tyrimas virpesinės spektroskopijos metodais

Matulaitienė, Ieva 06 January 2014 (has links)
Self-assembled monolayers provide possibility of changing metal surface properties in controllable manner and are widely used in studies of electron transfer, construction of (bio)sensors, and biotechnological and photoelectronic processes. Positively charged monolayers are valuable in development of sensors for anions and (bio)technological processes with adsorbed negatively charged macromolecules. In this work the structural and functional properties of monolayer formed from synthesized molecule with terminal thiol and pyridinium groups have been studied. The main tasks were to assess the structure of N-(6-mercapto)hexylpyridinium (MHP) on Ag and Au electrodes, and to determine the peculiarities of interaction with inorganic anions, dodecylsulfate, and graphene oxide. Based on surface enhanced Raman spectroscopy (SERS), quantum chemical calculations, and isotopic substitution studies, the Raman marker bands for structure and orientation of MHP have been evaluated. Dependence of SERS intensity on potential and excitation wavelength has revealed the operation of charge transfer Raman enhancement mechanism. It was found that the frequency of symmetric stretching mode of adsorbed ions decreases comparing with solution value and the extent of the shift correlates with the Gibbs dehydration energy. Adsorption of graphene oxide at MHP monolayer has been demonstrated. The electronic structure and length of C-C bonds of graphene oxide was found to be altered by the potential. / Savitvarkiai monosluoksniai suteikia metalų paviršiams norimas savybes ir plačiai taikomi elektronų pernašos tyrimuose, konstruojant (bio)jutiklius, biotechnologinius bei fotoelektroninius procesus. Teigiamo krūvio monosluoksniai naudojami kuriant anijonų jutiklius ir (bio)technologinius procesus su adsorbuotomis neigiamo krūvio makromolekulėmis. Darbe buvo susintetinta bifunkcinė molekulė su galinėmis tiolio ir piridinio grupėmis, suformuotas monosluoksnis ir ištirtos jo struktūrinės ir funkcinės savybės. Pagrindiniai darbo tikslai buvo ištirti N-(6-merkapto)heksilpiridinio (MHP) adsorbuoto ant Au ir Ag elektrodų struktūrą ir nustatyti monosluoksnio sąveikos su neorganiniais anijonais, dodecilsulfato anijonu ir grafeno oksidu dėsningumus. Naudojant paviršiaus sustiprintos Ramano spektroskopijos, kvantų chemijos skaičiavimo ir izotopinio pakeitimo metodus nustatyti MHP struktūros ir orientacijos elektrodo atžvilgiu Ramano sklaidos žymenys. Tiriant juostų intensyvumo priklausomybes nuo potencialo ir žadinančios spinduliuotės bangos ilgio parodyta, kad Au/MHP sistemoje pasireiškia krūvio pernešimo Ramano spektrų stiprinimo mechanizmas. Nustatyta, kad adsorbuotų neorganinių anijonų pilnai simetrinio virpesio dažnis sumažėja lyginant su tirpalo spektru ir tas pokytis koreliuoja su Gibso dehidracijos energija. Parodyta, kad MHP pritraukia grafeno oksidą. Nustatyta, kad grafeno oksido CC ryšio ilgis ir elektroninė struktūra gali būti keičiama, keičiant potencialą.

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