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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.
111

Improving Caco-2 cell permeability assay using phospholipid covered silica beads

Faradj, Lana January 2021 (has links)
The Caco-2 cell assay is widely used for in vitro permeability measurements. However, a draw back with the assay that this study will focus on improving, is compound adsorption to the plastic material. Lipophilic compounds such as Cyclosporin A and Peptide J, that will be used in this study, tend to bind to the plastic material in the assay. This can result in poor recovery and misleading permeability predictions. Bovine serum albumin (BSA) is an alternative used today to prevent this but is not always successful.    The aim of this study is therefore to improve the Caco-2 permeability assay by adding phospholipid covered silica beads (PLB) to the basolateral chamber. The role of the PLB is to bind the compound of interest and decrease the amount of compound bound to the plastic material and thus better predict the permeability of the compound of interest.   The PLB was produced using phosphatidylcholine and silica beads. Caco-2 cells were seeded and maintained for 21-29 days ahead of the experiment. PLB concentration of 20, 60 and 100 mg/ml were prepared. Samples were analyzed with HPLC-MSMS. The results showed that with increasing PLB concentration we had a significantly decrease in non-specific plastic binding resulting in reliable permeability predictions, concluding that the hypothesis was correct.
112

Bits & Bobs : Finds from a research excavation of Birka’s rampart: A study with focus on material distribution and metal conservation

Heljeback, Mikael January 2019 (has links)
In the spring of 2018, a prospection and subsequent research excavation of a previously unstudied area related to the rampart of the Viking age town of Birka, Sweden, was undertaken by students and professors from the archaeological science department affiliated with Stockholm University.The purpose of this paper is to examine and categorise the various excavated finds, the ensuing conservation and preservation of the metal objects as well as to investigate the context and possible function of the site regarding the spatial distribution of said finds.The main method used is that of metal conservation with the wet-chemical technique EDTA; a method that was deemed adequate for the treatment of the dry metal finds from the rampart excavation.The conservation and categorisation suggest that the metal posts consist of assorted metal objects, predominately rivets and nails as well as unidentified fragmented objects; the occasional slag fragment was evident. The material category of clay and ceramics contains assorted burnt clay and ceramic sherd fragments, some with decoration. Whetstone (or hone stone) and flint fragments make up most of the stone finds while the category of glass consists of a few bead fragments. The bulk of the osteological material consists of burnt and unburnt animal bones, some with slaughter marks in the form of cuts and hacks. Two human bone fragments were found; a humerus- and cranial fragment.Post holes and charcoal in the context of the rampart suggests the possibility of wooden supports and/or a superimposed wooden structure on the rampart itself that likely burnt at some point in time. The interpretation of the excavated area, based on the distribution of the finds and material categories, is that of a dumping site for discarded town refuse, most likely set against or near a walled construction; the rampart. The dating of the site is based on object similarities as well as stratigraphy and set to; Early to Late Viking Period, c. A.D. 820-1000(1150).The analyses, materials and the stratigraphy of the site together with a contextual analysis of the objects in question furthers the knowledge of Birka’s rampart and will enable future scientific inquiries into this specific rampart as well as similar fortification structures.
113

A Whole Blood/Plasma Separation Lab Chip using Hetero-packed Beads and Membrane Filters for Point-of-Care Test (POCT)

Shi, Shaojie 05 October 2021 (has links)
No description available.
114

Immobilization of Beta-Glycosidase BglX from Escherichia coli on Chitosan Gel Beads

Pickens, Tara L., L 30 August 2018 (has links)
No description available.
115

Studies on fluorophore-loaded polymer microbeads and luminescence lifetime encoding in flow cytometry

Kage, Daniel 24 October 2019 (has links)
Die Dissertation umfasst zwei Themenblöcke: Zum einen wurden die optisch-spektroskopischen Eigenschaften von fluoreszenten, farbstoffbeladenen Polymer-Mikropartikeln untersucht. Zum anderen wurde die Anwendbarkeit solcher Partikel für die Lumineszenzlebensdauer-Kodierung in der Durchflusszytometrie evaluiert. Die Charakterisierung der farbstoffbeladenen Mikropartikel erfolgte mittels optischer Spektroskopie. Am Beispiel mit Rhodamin 6G beladener Polymethylmethacrylat-Partikel konnte ein besseres Verständnis des Einbaus der Farbstoffmoleküle und der resultierenden Fluoreszenz-Charakteristika gewonnen werden. Es stellte sich heraus, dass die Beladungseffizienz stark vom mittleren Partikeldurchmesser und den Synthesebedingungen abhängt. In Verbindung mit den beobachteten optisch-spektroskopischen Eigenschaften wurde geschlussfolgert, dass sich eine farbstoffreiche Schicht an der Oberfläche der Partikel bildet, die sich wesentlich von den sterisch eingebauten Farbstoffmoleküle im Partikelvolumen unterscheidet. Hohe Farbstoffkonzentrationen in dieser Oberflächenschicht führen vermutlich zu Aggregation. Des Weiteren deuten Veränderungen der Fluoreszenzeigenschaften auf intrapartikuläre Energiewanderung bei zunehmender Farbstoffkonzentration hin. Diese Interpretation der experimentellen Ergebnisse konnte qualitativ durch einen Algorithmus zur Simulation der Energiewanderung bestätigt werden. Die Anwendbarkeit der Lumineszenzlebensdauer als Kodierungsparameter in der Zeitdomäne konnte unter Verwendung eines Durchflusszytometer-Prototypen analysiert werden. Die wohl größte Herausforderung bei der Lebensdauermessung in der Durchflusszytometrie ist die kurze Interaktionszeit zwischen Objekt und Anregungslicht. Synthetische Daten wurden herangezogen, um den Einfluss einzelner Messparameter und -bedingungen unabhängig voneinander abzuschätzen. Es konnte festgestellt werden, dass die Lumineszenzlebensdauer als Kodierungsparameter in der Zeitdomäne prinzipiell zugänglich ist. / This thesis comprises two main topics. First, the optical-spectroscopic properties of fluorescent microbeads loaded with organic dyes were studied. In the second part, the feasibility of time-domain luminescence lifetime encoding in flow cytometry based on such microbeads was assessed. The study of the dye-loaded polymer microbeads was based on optical spectroscopy. Poly(methyl methacrylate) beads loaded with rhodamine 6G were used as an example system to achieve a better understanding of the dye incorporation procedure. The dye loading efficiency turned out to be strongly dependent on the mean diameter of the beads and on the amounts of certain compounds used for the bead synthesis. In correlation with the observed fluorescence characteristics, it was deduced that a layer with high local dye concentration forms around each bead. The properties of this layer substantially differ from those of the sterically incorporated dye molecules in the bead core. The high dye concentration in this layer results in aggregation accompanied by the respective changes of the fluorescence characteristics of the beads. Moreover, the observed changes in fluorescence properties indicated the existence of an intra-particulate energy migration process at increased dye loading concentrations. A simulation of the energy migration process based on a random walk algorithm confirmed the interpretation of the experimental results. For the assessment of luminescence lifetime encoding in time-domain flow cytometry, a prototype setup was used. The main issue of lifetime determination in flow cytometry is represented by the short interaction time of only tens of microseconds of the objects with the excitation light spot. Synthetic data were used to study certain measurement parameters and conditions as well as the data analysis procedure independently of other influences. As a result, luminescence lifetime is generally applicable as an encoding parameter in time-domain flow cytometry.
116

Spermidine activates mitochondrial trifunctional protein and improves antitumor immunity in mice / スペルミジンはマウスにおいてMitochondrial trifunctional protein複合体を活性化させ抗腫瘍免疫を増強する

Al-Habsi, Muna Mohamed Ahmed 23 March 2023 (has links)
京都大学 / 新制・課程博士 / 博士(医学) / 甲第24487号 / 医博第4929号 / 新制||医||1063(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 竹内 理, 教授 上野 英樹, 教授 髙折 晃史 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM
117

Development and Evaluation of a Biopolymer based Ceftriaxone Sodium Oral Formulation

Patel, Nachiket January 2014 (has links)
No description available.
118

EQUIVALENECE OF ANTIBODY BINDING TO HLA ON BEADS AND CELLS: CRITICAL TESTS IN TRANSPLANATION

Brar, Balpreet January 2013 (has links)
<p>AMR as a cause of graft rejection has been long recognized and the presence of pre formed antibodies against donor HLA is a risk factor for increased graft rejection. FlowXM is the current clinical gold standard for detecting harmful DSA in the recipients and a positive FlowXM is considered a strong contraindication to transplantation. However, newer techniques such as SAB provide with a highly sensitive and specific method for DSA detection that is unattainable by FlowXM. But due to the intrinsic limitations associated with SAB assays, the clinical relevance of DSA detected on SAB has been highly disputable. Therefore, the overall aim of this study was to investigate the utility of SAB in predicting harmful DSA levels, by establishing a fluorescence range on SAB that correlated to positive FlowXM. This was done by retrospectively testing the highest serum dilutions on FlowPRA SAB that produced positive B or T cell FlowXM from 15 variably sensitized patients. Thus, a very narrow MFI range on SAB was established, for B and T cells separately, that correlated to positive FlowXM. On B cells this correlate ranged from 2780-7772 MFI (Mean MFI =5641), whereas T cell range was 1089-6731 (Mean MFI= 3226). In order to test these ranges for prediction of positive FlowXM, B and T cell FlowXM tests were carried out using various serum/cell combinations. DSA MFI of >3000 on SAB resulted in a significantly higher T cell positive FlowXM (p</p> / Master of Science (MSc)
119

Ölandskrukor : Romersk vardag - lyx på Gotland? / Ölandpots : Roman everyday items become luxury in Gotland?

Dalsbro, Åsa January 2017 (has links)
Two ceramic vessels of the Öland and Gotland type were in the summer of 2016 discovered at an archaeological excavation at the island of Gotland in the Baltic sea. They were produced with two different techniques of firing, resulting in two different colors of the surface of the pot. Ceramic vessels of the Öland and Gotland type dating from the Roman Iron Age are supposed to have been produced at these islands, but thin-section analysis of pottery found in Mälardalen in the mainland of Sweden show that at least some vessels are made of clay from Mälardalen. The type is distinct and differs both in form and composition of the clay from other ceramic vessels of more ordinary character. This type of ceramic vessel is supposed to be inspired of bronze vessels from the Roman Empire and ceramic vessels from both the Roman Empire and the Celtic area. In this thesis, the aim is to shed some light on the characters of this type of vessel with comparative and empirical studies of pots from Öland and Gotland. This is done by comparing vessels and described graves on the two islands. And for references a few pots from mainland Sweden is also studied. Is it possible to understand why the high-status pottery on Öland and Gotland differ from the rest of the Swedish mainland? Clearly, the wealth of the population on the islands was over average if we measure it in objects of foreign origin, compared with the Swedish mainland. Objects from the Roman Empire such as drinking equipment made of bronze and gold and silver coins made its way to the islands in bigger quantities than to rest of Scandinavia with exceptions from some local areas on the Swedish mainland. / • Vad exakt är en ölandskruka? • Varför finns en det en klar urskiljbar skillnad mellan den keramik vi kallar ölandskrukor/gotlandskrukor jämfört med andra kärl från samma period? • Vad kan dekor och utformning ha inspirerats av? • Är det klara skillnader mellan Öland och Gotland när det gäller ölandskrukorna, eller ser de lika ut på de båda öarna?Den kärltyp av keramik från romersk järnålder som vanligen kallas ölandskruka eller gotlandskruka i rapporter, litteratur eller andra arkeologiska sammanhang är vanlig i det öländska och gotländska materialet. Den hittas företrädesvis i gravar men även andra kontexter förekommer. Kärlen förekommer även sparsamt på det svenska fastlandet och hittas även där i gravar. Det är i de gravar som är rikast på föremål som den oftast påträffas och det pekar på att den är knuten till de personer i samhället som har högst social rang. Andra föremål som hittas tillsammans med ölandskrukor varierar en del mellan Öland och Gotland. Ett exempel på det är bronsskållor som mest är en gotländsk företeelse och endast förekommer sparsamt i det öländska materialet. Dryckeshorn i gravar är vanligast på Gotland och de förekommer ofta i gravar med sländtrissor. På Öland är det i kvinnogravarna vanligt att det förekommer krumknivar i samma grav som ölandskrukor medan mansgravarna ofta är så kallade vapengravar. Vapengravarna på Öland innehåller som regel ett svärd, minst en lansspets och en spjutspets men även fler förekommer, en sköld och en kniv.   Kärltypen som kallas ölandskruka är av tunt gods som glättats på ytan och oftast dekorerats med punktlinjer på den övre delen av skuldran. De är brända i en reducerad atmosfär som ger en svart yta på kärlet. I denna uppsats förekommer även en annan kärltyp med fyra stycken öron på skuldran, dessa kärl förefaller vara brända i en oxiderad atmosfär vilket istället resulterar i en brun eller rödbrun färg på ytan. Förutom dessa två kärltyper förekommer också kannor, de har en hank att hålla i när man häller och är i stort sett alltid dekorerade. Denna dekoration består ofta av olika fält på övre delen av kannan indelade i romber av linjer. I fälten finns olika stämpelmönster, till exempel cirklar, kryss, blomformade och trisklar. Kärlen är så kallad finkeramik som sannolikt inte användes till vardagligt bruk utan som serveringskärl vid till exempel gästabud och som gravgåvor i form av ett uppdukat bord till den avlidne. I en del fall även som benbehållare efter kremering. De kärl som betecknas som finkeramik förefaller ha använts till dryckesritualer och som serviser under gästabud. Även seden att ge den begravde ett dukat bord pekar på att kärlens betydelse var välkänd i det samtida samhället (Eriksson 2009:176ff). Ölandskrukorna introduceras i Mälardalsregionen under äldre romersk järnålder, men företrädesvis i elitmiljöer. Att det även på Öland och Gotland handlar om elitens föremål syns i gravmaterialet, då det är de gravar som är rikast på föremål som även har ölandskrukor, gotlandskrukor eller kannor (se bilaga 1 &amp; 2). Inspirationen till kärlen kan vara bronssitulor som importeras till Skandinavien under denna period (Eriksson 2009:176ff). Den polerade ytan på keramik som förekommer under bronsåldern i Mälardalen försvinner under förromersk järnålder och den tidigaste återkomsten av polerad keramik i området dateras till tiden efter Kristi födelse (Eriksson 2009:127). Dessa kärl har en svartglänsande yta som mycket väl kan tänkas föreställa eller efterlikna metall. Liknande former på kärl har bland annat hittas i tidigare nämnda Gödåker där ett kärl har en dekor som är klart inspirerad av samtida metallkonst. Det kan även finnas kopplingar till dryckesglas eftersom en del kärl har imitation av slipade glasfacetter. Mellan Öland och Gotland finns en del skillnader i utformningen på kärlen. På Öland är foten på ölandskrukorna mindre eller saknas. Eftersom tillverkningsort för ölandskrukorna inte har kunnat fastställas i nuläget är det svårt att peka på om det beror på att ölänningarna har en annan utformning på sina kärl än gotlänningarna eller om det förekommer variationer i båda regionerna som sedan distribuerats olika.
120

Supports organiques à base de polyisoprène pour la catalyse de polymérisation de l’éthylène

Heurtefeu, Bertrand 06 December 2010 (has links)
Les travaux décrits dans ce manuscrit ont trait à l’élaboration de supports organiques fonctionnels à base de polyisoprène pour la catalyse de polymérisation de l’éthylène par les métallocène et post-métallocène. Une série de polyisoprènes ω-OH et de copolymères à blocs de type polyisoprène-b-poly(méthacrylate de méthyle) et polyisoprène-b-poly(oxyde d’éthylène) de masse molaire variable a été réalisée par polymérisation anionique vivante. L’auto-assemblage dans l’heptane de ces (co)polymères conduit à la formation d’agrégats micellaires stables qui permettent l’immobilisation des systèmes catalytiques via des interactions créées entre le bloc polaire du support et l’activateur aluminique, le plus souvent le méthylaluminoxane. La polymérisation de l’éthylène en présence de ces supports organiques conduit, sans diminution d’activité catalytique, à la formation de particules de polyéthylène de taille micrométrique. Selon la même méthodologie, des polyisoprènes portant à leur extrémité une fonction borate ont été synthétisés et avantageusement utilisés comme supports activateurs de métallocènes pré-alkylés. Dans ce cas, des particules de polyéthylène de taille millimétrique ont pu être obtenues. / The work described in this manuscript relates the development of organic functional supports based on polyisoprene for the catalysis of ethylene polymerization by metallocenes and post-metallocenes. Polyisoprenes ω-OH and block copolymers [polyisoprene-b-poly(methyl methacrylate) and polyisoprene-b-poly(ethylene oxide)] with different molecular weights were synthesized by living anionic polymerization. Self-assembly in heptane of (co)polymers leads to the formation of stable micellar aggregates allowing the immobilization of catalytic systems created thanks to interactions between the polar block of the support and the aluminic activator, the most often methylaluminoxane. The ethylene polymerization in the presence of organic support drives, without loss of catalytic activity, to the formation of polyethylene particles of micrometer size. Using the same methodology, polyisoprenes bearing at their ends a borate function have been synthesized and advantageously used as supports activators of pre-alkylated metallocenes. In this case, polyethylene particles with a millimeter size have been obtained.

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