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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.
1

Anizotropinės plėvelės šviesos pralaidumas ir atspindys / Light reflection and transmission of anisotropic media

Bartkevičiūtė, Diana 29 June 2009 (has links)
Vienas iš efektyviausių medžiagos savybių tyrimo būdų yra praėjusios pro medžiagą ir atsispindėjusios nuo jos šviesos parametrų analizė. Darbe išnagrinėtas šviesos sklidimas anizotropine medžiaga,analizuojami būdai, suskaičiuojantys atsispindėjusios, praėjusios pro anizotropinę plėvelę atspindžio ir pralaidumo matricų elementai. / On purpose about structure of the light, you must to make measurement of light reflections and transmission parameters.In this work we finding following parameters with the help of the program “Mathematica 6”. I with “Mathematica 6 “can find the light reflection from anisotropic media and transmission through anisotropic media slab coefficient by the anisotropic media to matrixs.
2

Šviesos atspindys nuo homogeninės anizotropinės aplinkos / Light reflection of homogeneous anizotropic Media

Jurevičiūtė, Asta 16 August 2007 (has links)
Šiame darbe nagrinėjamas šviesos atspindžio parametrų priklausomybė nuo SbSI kristalo įvairių kristalografinių plokštumų atžvilgiu.Tai darboma sukurtos skaičiavimo programo spagalba. / On purpose about structure of the light, you must to make measurement of light reflections parameters. Following are outputting of equation of the Fresnel. Parameters of light reflection describe . In this work we finding following parameters with the help of the program “Mathematica”. And we finding the contingent on light incidence , rotate angle , anisotropy coefficient a.
3

Žmogaus augimo hormono kokybinio ir kiekybinio nustatymo fluorescenciniais metodais galimybės / Possibilities of qualitative and quantitative determination of the human growth hormone using fluorescence methods

Jarienė, Giedrė 17 May 2006 (has links)
Abbrevations t – fluorescence lifetime j – rotational correlational time ([Ru(bpy)2(phen-ITC)]2+) – Bis-(bipyridine)-5-(isotiocyanatophenantrolin)-Ru(PF6-)2 Ab – antibody AF – Alexa Fluor 660 AF-hGH – with Alexa Fluor 660 labelled human growth hormone FITC – fluorescein isothiocyanate FITC-Ab – FITC labelled antibody FP – fluorescence polarization FRET – fluorescence resonance energy transfer hGH – human growth hormone PMI – N-(3-pyrene)maleimide PMI-hGH – human growth hormone labelled N-(3-pyrene)maleimide PVPPB – poly(N-vinyl-2-pyrolidone) with phenylboronic acid copolymer r – anisotropy RITC – rodamine B isothiocyanate RITC-hGH – with RITC labeled human growth hormone SDS-PAGE – sodium dodecylsulfate-polyacrylamide gel electrophoresis INTRODUCTION Relevance of the study. Human growth hormone (hGH) is a heterogeneous protein with several molecular forms (isoforms). Human growth hormone measurements are complicated because of the heterogeneous nature of hGH. Specific assays for each isoform are currently unavailable. Because the different antibodies used in immunoassays bind to a different spectrum of hGH isoforms, hGH concentrations measured by immunoassay are likely to depend on the particular antibody used. Moreover, because the distribution of the different hGH isoforms varies among individuals, the results from different immunoassays cannot be interrelated easily by using a single conversion factor. Fluorescence is by far the most important optical... [to full text]
4

Epitaksinių InGaAs kvantinių taškų darinių moduliuoto atspindžio ir fotoliuminescencijos spektroskopija / Modulated Reflectance and Photoluminescence Spectroscopy of Epitaxial InGaAs Quantum Dot Structures

Nedzinskas, Ramūnas 01 October 2012 (has links)
Saviformuojantys puslaidininkiniai kvantiniai taškai (quantum dots, QDs), kurių charakteringos elektronų subjuostinių (intraband) šuolių energijos yra infraraudonajame spektriniame ruože (3–25 μm), sudaro daugelio fotojutiklių aktyviąją terpę ir yra aktualūs taikymams šiuolaikinėje optoelektronikoje. Disertacijoje nagrinėjami molekulinio pluoštelio epitaksijos būdu užauginti: -- InAs kvantiniai taškai, įterpti į GaAs matricą ir GaAs/AlAs supergardelę; -- InAs kvantiniai taškai be ir su įtempimus sumažinančiuoju InGaAs sluoksniu, įterpti į kompozitinę GaAs/AlAs kvantinę duobę; -- skirtingo aukščio koloniniai InGaAs kvantiniai taškai arba kvantiniai strypeliai (quantum rods, QRs), apsupti dvimačiu InGaAs sluoksniu, ir užauginti naudojant arba As2, arba As4 šaltinį. Taikant moduliacinę atspindžio spektroskopiją ir fotoliuminescenciją, buvo ištirtos šių darinių optinės savybės bei jų elektroninė sandara, o taip pat atskleista auginimo sąlygų įtaka darinių struktūrai. Eksperimentiniai tyrimai buvo interpretuojami atliekant teorinį modeliavimą skaitmeniniu (nextnano3 programa) bei analitiniu (sukurtas algoritmas) metodais. / Self-assembled InAs quantum dots (QDs), whose intersublevel transition energies lie in the mid- and far-infrared spectral range (3–25μm), have attracted particular interest as active elements of infrared photodetectors. This interest is mainly due to intriguing atomic-like quantum confinement and unique optical and electronic properties of QDs. Moreover, QD electronic structure can be adjusted by varying the dots size and shape or their environment. These features make QDs to be of importance in creation of photoelectronic devices with a desired spectral range. The dissertation is concerned specifically with molecular beam epitaxy grown InGaAs QD structures with: -- InAs QD stacks embedded in GaAs matrix and GaAs/AlAs superlattice (SL), or alternatively InAs/GaAs QD-SL structures with and without AlAs barriers between the dot layers; -- InAs QDs with and without InGaAs strain-reducing layers, embedded within GaAs/AlAs quantum wells; -- columnar InGaAs QDs, also referred to as quantum rods (QRs) or quantum posts, of different morphology. (The quantum confined structure consists of vertically oriented InGaAs QRs immersed in a two-dimensional InGaAs layer). These QD structures were studied by modulated reflectance and photo- luminescence spectroscopies to reveal their optical properties and the full- extent of electronic structure. Experimental data were interpreted by numerical (nextnano3 software) and analytical (algorithm developed) modelling.
5

Funkcionalni magnetno rezonantni imidžing u dijagnostici dijabetesne nefropatije kod bolesnika sa tipom 2 dijabetes melitusa / Functional magnetic resonance imaging in the diagnosis of diabetic nephropathy in patients with type 2 diabetes mellitus

Mrđanin Tijana 06 June 2019 (has links)
<p>Uvod: Dijabetes melitus (DM) je oboljenje koje poprima karakteristike globalne epidemije. Sve ţe&scaron;&scaron;e oboljevaju pacijenti mlaŤeg ţivotnog doba. Simptomi DM tip 2 su blagi, ţesto neprimetni, te se oboljenje otkriva kada se ve&scaron; manifestuju komplikacije. Dijabetesna nefropatija (DN) je jedna od mnogobrojnih komplikacija dijabetes melitusa tip 2, koja se zavr&scaron;ava terminalnom bubreţnom insuficijencijom. DN se ţesto neblagovremeno dijagnostikuje, zbog ţega se kasno zapoţinje leţenje. Rano otkrivanje DN od kljuţnog je znaţaja, jer omogu&scaron;ava primenu terapijskih postupaka usmerenih na oţuvanje preostalih zdravih nefrona i prevenciju terminalne bubreţne slabosti. Cilj: Prikazati poreme&scaron;aj difuzije molekula vode unutar bubrega kod DN, kori&scaron;&scaron;enjem mapa prividnog koeficijenta difuzije, kvantifikacijom vrednosti prividnog koeficijenta difuzije (ADC) i frakcione anizotropije (FA). Materijal i metode: U prospektivnu studiju bilo je ukljuţeno 10 zdravih dobrovoljaca i 91 pacijent oboleo od DM tip 2. Pacijenti oboleli od DM tip 2 podeljeni su u ţetiri grupe na osnovu vrednosti procenjene jaţine glomerularne filtracije (JGF) (grupe: I JGF &ge; 90, II 89-60, III 59-30, IV &le; 29 ml/min/1,73m&sup2;). Svim ispitanicima uraŤen je MR pregled bubrega, uz primenu DWI (b=0 i b=400 s/mm&sup2;) i DTI (b=1000 s/mm&sup2;) sekvence, na aparatu jaţine 1.5T. ADC i FA vrednosti raţunate su u &scaron;est regija od interasa, po tri u korteksu i meduli svakog bubrega. Dobijene vrednosti komparirane su sa laboratorijskim parametrima bubreţne funkcije (urea, kreatinin, mokra&scaron;na kiselina) i procenjenom JGF. Rezultati: Ne postoje statistiţki znaţajne razlike ADC i FA vrednosti parenhima, korteksa i medule levog i desnog bubrega kod zdravih dobrovoljaca i DM pacijenata. Kod DM pacijenata ADC je ve&scaron;a u korteksu nego u meduli (p=0,00), a FA vrednost je ve&scaron;a u meduli nego u korteksu (p=0,284). Urea, kreatinin i cistatin C imaju negativnu korelaciju sa ADC korteksa, medule i parenhima (p&lt;0,05), a JGF ima pozitivnu korelaciju sa ADC korteksa, medule i parenhima, kao i sa FA medule (p&lt;0,05) kod DM pacijenata. Na osnovu Post hoc testa za ADC, kod DM pacijenata postoje razlike izmeŤu I i IV grupe, izmeŤu II i IV grupe i III i IV grupe (p&le;0,05). IzmeŤu godina ţivota, teţine, BMI, JGF, HbA1c, uree i &Scaron;UK-a, postoji razlika DM pacijenata i zdravih dobrovoljaca (p&lt;0,05). Niţa je vrednost FA medule DM pacijenata u odnosu na zdrave dobrovoljce (p&lt;0,05). Postoji razlika ADC korteksa, medule i parenhima izmeŤu zdravih dobrovoljaca i DM pacijenata IV grupe, kao izmeŤu DM pacijenata I i II grupe u odnosu na IV grupu. TakoŤe postoji razlika izmeŤu FA medule zdravih dobrovoljaca i DM pacijenata I i IV grupe (p&lt;0,05). Regresiona analiza pokazala je uticaj kreatinina na ADC desnog bubrega i ADC oba bubrega, dok procenjena JGF i cistatin C imaju uticaj na ADC desnog i levog bubrega, ADC oba bubrega i FA levog bubrega (p&lt;0,05). Traktografija je prikazala naru&scaron;enu arhitektoniku kod pacijenata sa o&scaron;te&scaron;enom bubreţnom funkcijom. Zakljuţak: Postoji korelacija laboratorijskih parametara bubreţne funkcije i procenjene JGF sa ADC i FA vrednostima bubrega, &scaron;to ukazuje na ulogu funkcionalnog magnetno rezonantnog imidţinga u dijagnostici dijabetesne nefropatije. Neophodna su dalja istraţivanja koja &scaron;e doprineti standardizaciji MR protokola i potvrdi znaţaja MR biomarkera u dijagnostici DN. Na osnovu na&scaron;ih rezultata vrednost FA medule osetljiviji je parametar od ADC vrednosti u otkrivanju ranog o&scaron;te&scaron;enja bubrega u sklopu dijabetes melitusa.</p> / <p>Introduction: Diabetes mellitus (DM) is a disease that takes on the characteristics of a global epidemic. Patients of younger age are more and more commonly affected. Symptoms of type 2 DM are mild, often imperceptible, and therefore the disease is usually detected when complications are already manifested. Diabetic nephropathy (DN) is one of the many complications of type 2 diabetes mellitus that leads to terminal renal failure. Diagnosis of DN is often late, causing the delay of the treatmen. Early detection of DN is crucial because it allows the application of therapeutic procedures aimed at preserving the remaining healthy nephrons and preventing terminal renal failure. Objective: To investigate a diffusion of water molecule within a kidney in DN using apparent diffusion coefficient maps, by quantification of the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values in diabetic patients with DM type 2. Material and methods: The prospective study comprised 10 healthy volunteers and 91 DM type 2 patients. DM patients were divided into four groups based on the values of the estimated glomerular filtration (eGFR) (groups: I eGFR &ge; 90, II 89-60, III 59-30, IV &le; 29 ml/min/1.73m&sup2;). All subjects were scanned by 1.5T MR using DWI (b=0 and b=400 s/mm&sup2;) and DTI (b=1000 s/mm&sup2;) sequences. ADC and FA values were calculated in six regions of interest, three in cortex and three in medulla of each kidney. Obtaned values were compared to laboratory parameters of renal function (urea, creatinine, uric acid) and eGFR. Results: There were no statistically significant differences between ADC and FA values of parenchyma, cortex and medulla of the left and the right kidney in healthy volunteers and DM patients. In DM patients, the ADC value was higher in the cortex than in the medulla (p=0.00) and the FA value was higher in the medulla than in the cortex (p=0.284). The negative correlation was found between urea, creatinine and cystatin C with ADC cortex, medulla and parenchyma (p&lt;0.05), and the eGFR was positively correlated with ADC cortex, medulla and parenchyma, and with FA medulla (p&lt;0.05) in DM patients. Based on the Post hoc test for ADC, in DM patients there were differences between I and IV group, between II and IV group, III and IV group (p&le;0,05). Regarding age, weight, BMI, GFR, HbA1c, urea, and glucose in the serum, there was a difference between DM patients and healthy volunteers (p&lt;0.05). The FA of medulla in DM patients was lower than of healthy volunteers (p&lt;0.05). There were differences in ADC of cortex, medulla, and parenchyma between healthy volunteers and DM patients of IV group, as well as between DM patients of I and II group compared to IV group. There were differences of medulla FA values between healthy volunteers and group I, accompanied by healthy and IV group of DM patients (p&lt;0.05). Regression analysis showed the influence of creatinine on ADC of right kidney and ADC of both kidneys, while eGFR and cystatin C have an effect on ADC of right and left kidney, ADC of both kidneys and FA of left kidney (p&lt;0.05). The tractography showed the disturbed architectonics in patients with impaired renal function. Conclusion: There is correlation of laboratory parameters of renal function and eGFR with ADC and FA values of the kidney, indicating the role of functional magnetic resonance imaging in the diagnosis of DN. Further research that will contribute to standardizing the MR protocol and confirming the importance of MRI biomarker in the diagnosis of DN are needed. Based on our results, the values of medulla FA is more sensitive parameter than the ADC value in detecting early kidney damage in the context of diabetes mellitus.</p>

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