{"id":5974,"date":"2026-10-19T09:48:16","date_gmt":"2026-10-19T09:48:16","guid":{"rendered":"https:\/\/phd.hi.is\/doktorsvorn\/doktorsvorn-i-lif-og-laeknavisindum-freyr-johannsson\/"},"modified":"2026-10-19T09:48:16","modified_gmt":"2026-10-19T09:48:16","slug":"doktorsvorn-i-lif-og-laeknavisindum-freyr-johannsson","status":"publish","type":"phd_defence","link":"https:\/\/phd.hi.is\/en\/doktorsvorn\/doktorsvorn-i-lif-og-laeknavisindum-freyr-johannsson\/","title":{"rendered":"Doktorsv\u00f6rn \u00ed l\u00edf- og l\u00e6knav\u00edsindum &#8211; Freyr J\u00f3hannsson"},"content":{"rendered":"<div class=\"field-items\">\n<div class=\"field-item even\" property=\"content:encoded\">\n<p>Mi\u00f0vikudaginn 26. febr\u00faar ver Freyr J\u00f3hannsson doktorsritger\u00f0 s\u00edna \u00ed l\u00edf- og l\u00e6knav\u00edsindum vi\u00f0 L\u00e6knadeild H\u00e1sk\u00f3la \u00cdslands. Ritger\u00f0in ber heiti\u00f0: <strong>Greining \u00e1 efnaskiptaferlum bl\u00f3\u00f0flagna vi\u00f0 geymslu \u00ed bl\u00f3\u00f0banka. Systems analysis of platelet metabolism during storage of platelet concentrates.<\/strong><\/p>\n<p>Andm\u00e6lendur eru dr. Nikolaus Sonnenschein, d\u00f3sent vi\u00f0 Danmarks Tekniske Universitet og dr. Magn\u00fas Karl Magn\u00fasson, pr\u00f3fessor vi\u00f0 L\u00e6knadeild H\u00e1sk\u00f3la \u00cdslands.<\/p>\n<p>Umsj\u00f3narkennari og lei\u00f0beinandi var dr. \u00d3ttar Rolfsson, pr\u00f3fessor vi\u00f0 L\u00e6knadeild, og me\u00f0lei\u00f0beinandi var dr. \u00d3lafur E. Sigurj\u00f3nsson, pr\u00f3fessor. Auk \u00feeirra s\u00e1tu \u00ed doktorsnefnd \u00feau dr. Steinn Gu\u00f0mundsson, d\u00f3sent, dr. Margr\u00e9t \u00deorsteinsd\u00f3ttir, pr\u00f3fessor og dr. Giuseppe Paglia, pr\u00f3fessor.<\/p>\n<p>Engilbert Sigur\u00f0sson, pr\u00f3fessor og forseti L\u00e6knadeildar H\u00e1sk\u00f3la \u00cdslands, stj\u00f3rnar ath\u00f6fninni sem fer fram \u00ed H\u00e1t\u00ed\u00f0asal H\u00e1sk\u00f3la \u00cdslands og hefst kl. 13:00.<\/p>\n<p><strong>\u00c1grip af ranns\u00f3kn<\/strong><\/p>\n<p>Bl\u00f3\u00f0fl\u00f6gugjafir eru mikilv\u00e6gur \u00fe\u00e1ttur \u00ed n\u00fat\u00edma l\u00e6knav\u00edsindum. Bl\u00f3\u00f0fl\u00f6gur eru geymdar \u00ed\u00a0 bl\u00f3\u00f0b\u00f6nkum sem bl\u00f3\u00f0fl\u00f6gu\u00feykkni. Geymslut\u00edmi bl\u00f3\u00f0fl\u00f6gu\u00feykknis takmarkast af aukinni smith\u00e6ttu og hr\u00f6rnun bl\u00f3\u00f0flagna sem \u00e1 s\u00e9r sta\u00f0 vi\u00f0 geymslu. Efnaskiptaferlar eru virkir \u00ed bl\u00f3\u00f0fl\u00f6gum vi\u00f0 geymslu og taldir skipta sk\u00f6pum \u00feegar kemur a\u00f0 hr\u00f6rnun \u00feeirra. \u00cdtarleg \u00feekking \u00e1 efnaskiptaferlunum er \u00fev\u00ed nau\u00f0synleg svo skilja megi samband \u00feeirra vi\u00f0 \u00fe\u00e6r ska\u00f0legu breytingar sem eiga s\u00e9r sta\u00f0 vi\u00f0 geymslu. Markmi\u00f0 verkefnisins var a\u00f0 rannsaka efnaskiptaferla bl\u00f3\u00f0flagna vi\u00f0 mismunandi geymslua\u00f0st\u00e6\u00f0ur. Efnaskiptamengi bl\u00f3\u00f0flagnanna var m\u00e6lt me\u00f0 massagreini og ni\u00f0urst\u00f6\u00f0ur m\u00e6linganna greindar me\u00f0 s\u00e9rtilger\u00f0u reiknil\u00edkani. Verkefni\u00f0 skiptist \u00ed \u00ferj\u00e1 hluta. \u00cd \u00feeim fyrsta var reiknil\u00edkan af bl\u00f3\u00f0fl\u00f6guefnaskiptum uppf\u00e6rt og \u00fea\u00f0 nota\u00f0 til greiningar \u00e1 fyrirliggjandi g\u00f6gnum um efnaskiptamengi bl\u00f3\u00f0flagna vi\u00f0 geymslu. \u00a0Me\u00f0 notkun reiknil\u00edkansins var unnt a\u00f0 sp\u00e1 fyrir um virkni innanfrumu-efnaskiptaferla \u00e1 heildr\u00e6nan h\u00e1tt, sem ekki v\u00e6ri m\u00f6gulegt annars. \u00cd \u00f6\u00f0rum hluta verkefnisins voru \u00e1hrif Intercept smithreinsunart\u00e6kninnar \u00e1 efnaskipi bl\u00f3\u00f0flagna ranns\u00f6ku\u00f0. \u00cd \u00feri\u00f0ja og s\u00ed\u00f0asta hluta verkefnisins voru \u00e1hrif hitastigs \u00e1 efnaskiptaferla bl\u00f3\u00f0flagna vi\u00f0 geymslu ranns\u00f6ku\u00f0. Reiknil\u00edkan bl\u00f3\u00f0fl\u00f6guefnaskipta \u00e1samt efnaskiptam\u00e6lingum voru notu\u00f0 til a\u00f0 rannsaka hver \u00e1hrif hitastigs eru \u00e1 efnaskiptanet bl\u00f3\u00f0flagna.<\/p>\n<p><strong>Abstract<\/strong><\/p>\n<p>Platelet transfusion is an essential part of modern medicine. Platelets are stored at blood banks as platelet concentrates. The shelf-life of platelet concentrates is limited by the increased risk of pathogen contamination and a storage-induced loss of quality. Cellular metabolism is believed to be an important factor in the progressive loss of platelet quality during storage. In order to understand the links \u00a0between \u00a0metabolism and the underlying mechanisms \u00a0behind the physiological changes observed during storage, a delineation of platelet metabolism is necessary. This thesis aimed to investigate the metabolism of stored platelets under conditions \u00a0relevant \u00a0to \u00a0transfusion \u00a0medicine \u00a0by performing metabolomics analysis of stored platelets, and by using constraint-based modeling to integrate the metabolomics data with a platelet metabolic reconstruction. The thesis is in three parts: In the first part, a platelet metabolic reconstruction was refined and used for the systems analysis of metabolomics data previously generated by members of our group. The study described the metabolism of apheresis, and buffy coat derived platelets during storage at the metabolic network level. In the second part, the effects the Intercept pathogen reduction system has on platelet metabolism were investigated. The third and final part describes the effects of temperature on platelet metabolism. Metabolic modeling was used in combination \u00a0with \u00a0metabolomics \u00a0analysis to \u00a0investigate the temperature dependence of individual pathways and reactions. \u00a0<\/p>\n<p><strong>Um doktorsefni\u00f0<\/strong><\/p>\n<p>Freyr J\u00f3hannsson er f\u00e6ddur \u00e1ri\u00f0 1983. Hann lauk BS-pr\u00f3fi \u00ed l\u00edfefna- og sameindal\u00edffr\u00e6\u00f0i \u00e1ri\u00f0 2014 og sama \u00e1r h\u00f3f hann n\u00e1m til meistara- og doktorspr\u00f3fs \u00ed l\u00edf- og l\u00e6knav\u00edsindum vi\u00f0 H\u00e1sk\u00f3la \u00cdslands. Foreldrar Freys eru J\u00f3hann \u00de\u00f3r Sigur\u00f0sson og J\u00fal\u00edana Gunnarsd\u00f3ttir. Maki Freys er Qiong Wang.<\/p>\n<\/div><\/div>","protected":false},"featured_media":1150,"template":"","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"_phd_date_start":"2020-02-26T13:00:00+00:00","_phd_date_end":"2020-02-26T16:00:00+00:00","_phd_location":"A\u00f0albygging H\u00e1t\u00ed\u00f0asalur","_phd_admission":"A\u00f0gangur \u00f3keypis","_phd_thesis_title":"Greining \u00e1 efnaskiptaferlum bl\u00f3\u00f0flagna vi\u00f0 geymslu \u00ed bl\u00f3\u00f0banka. 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