Intravenous contrast media optimization at computed tomography

The administration of intravenous contrast media (IV CM) is essential for detecting lesions at most computed tomography (CT) examinations. The overall aim of this thesis is to investigate different aspects of IV CM administration that may affect the quality of the CT examination. In Study I a comparison was made between a low-osmolar contrast media (LOCM) iomeprol and the iso-osmolar contrast medium (IOCM) iodixanol, focusing on how they affect heart rate (HR), influence patient heat sensation and image quality during coronary computed angiography (CCTA). No significant difference in terms of HR interfering with the imaging protocol was observed. However, there was a larger number of arrhythmic heart beats (HB) observed when using LOCM in comparison to IOCM (p < 0.001). There was no statistically significant difference in image quality between the two CM. The experienced heat sensation was significantly stronger with LOCM in comparison to IOCM (visual analogue scale = 36 mm and 18 mm respectively, p< 0.05). In Study II the variation in IV CM-enhancement in Hounsfield units (HU) in the liver and the aorta in relation to different expressions of body size was studied using two different CM (LOCM iomeprol and IOCM iodixanol). A significant relationship was observed for all studied body size parameters. Three parameters had a stronger correlation to the CM-enhancement; Body weight (BW, r= -0.51 and -0.64 ), body surface area (BSA, r= -0.54 and -0.65) and lean body mass (LBM, r= -0.54 and -0.59), but there was no statistically significant difference between those. Body height (BH), body mass index (BMI) and ideal body weight (IBW) had weaker correlations to CM- enhancement of the liver and the aorta. When adjusting for differences in weight, height, age and sex between the two groups there was a significantly stronger liver enhancement with iodixanol than with iomeprol (mean difference 6 HU, p < 0.01). In Study III the correlation between liver CM-enhancement and volume pitch-corrected computed tomographic dose index (CTDIvol) and BW was studied. Liver enhancement was negatively correlated to both CTDIvol (r = -0.60) and BW (r = -0.64). In Study IV the relationship between arm positioning, BW and cardiac output (CO) versus CM-enhancement /timing during CCTA was studied. Patients were randomized into two groups. Group A (n=50) was positioned with arms resting on a pillow above their head and Group B (n=50) with their arms resting on the front panel of the CT. Statistically significant more patients in group A compared with group B (26 versus 14) showed a higher attenuation of the left atrium in comparison to the ascending aorta indicating too early scanning after IV CM injection (p=<0.05). In both groups BW and CO were statistically significantly related to the attenuation of ascending aorta (p<0.01). Conclusion: The iso-osmolar contrast medium iodixanol causes less arrhythmic HB and less heat sensation than the low-osmolar contrast medium iomeprol, but this does not significantly influence the quality at CCTA. The positioning of the arms affects contrast media timing at CCTA. CM-enhancement of the liver and aorta is affected by body size. Several parameters can be used to adjust CM dose, but none is statistically significantly better parameter than BW. However, CTDIvol can potentially replace BW when adjusting CM dose for body size. This would make it potentially feasible to individualize CM dosage automatically by the CT scanner

Evaluation of Nordic heritage varieties and NILs for resistance to common bunt (Tilletia caries syn. T.tritici)

A number og wheat varieties from NordGen and Allkorn were tested fro susceptibility to common bunt. Most were susceptible to common bunt which is in line with other screening experiments of randomly selected varieties. However, a few lines not previously known to be resistant were shown to have different resistance genes. None of them however were resistant to all the virulence races tested. NILs developed by MacKey were evaluated and there seem to be a potential for using some of them as differential lines for resistance gene Bt1, Bt5, and Bt9. Purification based on resistant head rows may also develop NILs with resistance to Bt6 and Bt10 and possible also Bt7 from NGB16160. A crossing program of the remaining Bt-genes was started in 2016. The NILs may be used also to support development of genetic markers of the resistance genes

Recent results from the Greenland NEEM ice core

第2回極域科学シンポジウム　氷床コアセッション 11月16日（水） 国立極地研究所 2階大会議

The Employment Effect of Stricter Rules for Eligibility for DI: Evidence from a Natural Experiment in Sweden

We study the effect of a reform of the Swedish disability insurance (DI) program whereby the special eligibility rules for workers in the age group 60 to 64 were abolished. First, we use a differences-in-differences approach to study changes in the disability take-up as compared to the age group 55 to 59. Then, we use a similar approach to study to what extent the employment effect of the reform is "crowded out" by an increase in the utilization of the sickpay insurance (SI) and/or the unemployment insurance (UI). In an extended analysis, we study the effect of firm closure on employment and the utilization of different labor market insurance programs in different age groups before and after the reform.Disability Insurance; Early Retirement

Investigation of Starch Binding Domains for Improvement of Starch degradation

Dansk resume Stivelse er planternes primære energilager og et vigtigt næringsmiddel for pattedyr,svampe og bakterier. Stivelse deponeres i højt organiserede semi-krystallinske stivelseskorn i plastider: kloroplaster i blade (transitorisk stivelse) og amyloplaster i lagerorganer som knolde. Stivelse består udelukkende af α-1,4-bundne glukose enheder, som er organiseret enten som det stort set lineære amylose molekyle eller det forgrenede amylopektin molekyle, der indeholder α-1,6-bindinger. Rod og knold stivelse er karakteriseret ved et højt niveau af kovalent bundet fosfat. Denne stivelsesbundne fosfat har en stor effekt på både stivelsens fysiske egenskaber samt på stivelsesnedbrydning i planterne. Inkludering af fosfatestre påvirker de industrielle egenskaber, og medfører forskellige meget ønskværdige egenskaber. Enzymet der kan inkorporere fosfat grupper i stivelse er en glucan, water dikinase (GWD). GWD kan fosforylere i C-3 og C-6 positionen i glukose enhederne i stivelse, ved en dikinase reaktion der anvender β-fosfat fra ATP. Mutanter i Arabidopsis thaliana GWD1 udviser en stivelses overskud fænotype med en lavere stivelses nedbrydnings rate, hvilket påviser en forbindelse mellem stivelses fosforylering og stivelses nedbrydning. To homologe proteiner er blevet identificeret i Arabidopsis genomet, navngivet AtGWD2 og AtGWD3. Mutationer i AtGWD3 resulterede også i en stivelses overskud fænotype, som set hos AtGWD1, hvilket tyder på AtGWD3 også er involveret i stivelses nedbrydning. AtGWD3 er lokaliseret i kloroplasterne og substrat analyser viste at oprenset AtGWD3 udviser præference for fosforyleret α-glucaner og katalysere udelukkende fosforylering i C-3 positionen i glukose enhederne. Disse resultater tyder på at AtGWD1 og AtGWD3 arbejder sammen i en efterfølgende fosforyleringskaskade, som er nødvendig for nedbrydning af stivelse. Glycosyl hydrolasers nedbrydning af rå stivelse er relativ ineffektiv, da polysacharrid kæderne ofte ikke er blotlagte og tilgængelige for enzymernes aktive site. Mange stivelses nedbrydende enzymer har ekstra bindings sites i det katalytiske domæne eller på separate stivelsesbindings domæner (SBD) som muliggør denne interaktion. SBDer er klassificeret i CAZy databasen i forskellige kulhydrat bindings module (CBM)familier. AtGWD1 og AtGWD2 har et tandem repeat af SBDer som tilhører familie CBM45 og AtGWD3 har et enkelt SBD fra familie CBM20. Alle er N-terminalt lokaliseret. Formålet med dette PhD projekt har været at undersøge og karakterisere GWD3-SBDs biokemiske funktion. GWD3-SBD er blevet udtrykt succesfuldt som et isoleret domæne i E. coli og oprenset. Øget stabilitet af domænet blev opnået efter yderligere aminosyrer blev inddraget i den kodende sekvens. Binding til 5 stivelseskorn var svært at måle, og det skyldes højst sandsynligt konsekvensen af den højt specialiserede rolle som GWD3 spiller i stivelses fosforyleringen. Enzymet er reguleret i kloroplasten og kun meget specialiserede områder på stivelses kornene er egnede for fosforylering i C-3 positionen og det er svært at finde forhold, hvor alle parametre er optimale. Binding til små ligosaccharider, som β-cyclodextrins (β-CD) er blevet bestemt med Surface plasmon resonance og domænet tilhører en gruppe af lav affinitets bindere, denne kategori inkluderer ikke-hydrolyserende enzymer. Den overordnede struktur fundet hos CBM20 er ifølge en homologimodellering bevaret i GWD3-SBD og bindings site 1, som er involveret i initial binding er vel bevaret både i strukturen og på sekvens niveau. Sammenlignet med andre karakteriserede CBM20, så har GWD3-SBD et mindre loop i området omkring bindings site 2. Dette loop er under substrat binding i andre CBM20 meget fleksibelt og dette kan forklare den lavere bindings kapacitet fundet hos GWD3- SBD. Fluorescens mærkning og confocal laser scanning microskopi er blevet anvendt som en metode til at visualisere SBD og hydrolyserende enzymers, f.eks. glucoamylase og α-amylases binding til stivelseskorn. Denne metode blev anvendt sammen med transient ekspression af en yellow-fluorescent protein YFP-GWD3-SBD fusion i tobaksplanter for at verificeres stivelsesbinding

Tailoring Charge Recombination in Photoelectrodes Using Oxide Nanostructures

Optimizing semiconductor devices for solar energy conversion requires an explicit control of the recombination of photogenerated electron hole pairs. Here we show how the recombination of charge carriers can be controlled in semiconductor thin films by surface patterning with oxide nanodisks. The control mechanism relies on the formation of dipole-like electric fields at the interface that, depending on the field direction, attract or repel minority carriers from underneath the disks. The charge recombination rate can be controlled through the choice of oxide material and the surface coverage of nanodisks. We provide proof-of-principle demonstration of this approach by patterning the surface of Fe2O3, one of the most studied semiconductors for light-driven water splitting, with TiO2 and Cu2O nanodisks. We expect this method to be generally applicable to a range of semiconductor-based solar energy conversion devices

Molecular Basis of Enhanced Activity in Factor VIIa-Trypsin Variants Conveys Insights into Tissue Factor-mediated Allosteric Regulation of Factor VIIa Activity

The complex of coagulation factor VIIa (FVIIa), a trypsin-like serine protease, and membrane-bound tissue factor (TF) initiates blood coagulation upon vascular injury. Binding of TF to FVIIa promotes allosteric conformational changes in the FVIIa protease domain and improves its catalytic properties. Extensive studies have revealed two putative pathways for this allosteric communication. Here we provide further details of this allosteric communication by investigating FVIIa loop swap variants containing the 170 loop of trypsin that display TF-independent enhanced activity. Using x-ray crystallography, we show that the introduced 170 loop from trypsin directly interacts with the FVIIa active site, stabilizing segment 215–217 and activation loop 3, leading to enhanced activity. Molecular dynamics simulations and novel fluorescence quenching studies support that segment 215–217 conformation is pivotal to the enhanced activity of the FVIIa variants. We speculate that the allosteric regulation of FVIIa activity by TF binding follows a similar path in conjunction with protease domain N terminus insertion, suggesting a more complete molecular basis of TF-mediated allosteric enhancement of FVIIa activity

Femur shaft fracture at a young age and the risk of subsequent severe injuries during childhood: a cohort study

Background: A child who suffers a fracture or a soft-tissue injury at a young age faces an increased risk of subsequent injuries during childhood. This risk could be related to personal and family characteristics or to lower-than-average bone-mineral density. The purpose of this nationwide cohort study was to estimate the association between a femur shaft fracture at a young age and the subsequent risk of hospitalization for injuries during childhood. Methods: We compared the subsequent risk of hospitalization for injuries during childhood among 1,404 children (exposed) who were one to three years of age when they suffered a femur shaft fracture with the risk among 13,814 randomly selected, gender- and age-matched femur fracture–free children (unexposed). Hazard ratios (HRs) and 95% confidence intervals (CIs) for severe injuries defined as fractures or soft-tissue injuries requiring hospital admission were estimated in a Cox proportional hazards model. Results: Exposed children exhibited no significantly increased risk of upper-extremity fractures or soft-tissue injuries during childhood, regardless of sex and follow-up time. Boys exhibited a 162% increased risk of suffering a lower leg fracture requiring hospital admission (HR?=?2.62, 95% CI: 1.45–4.71), but the refracture risk was not significant for girls 2.02 (0.58–6.97). Conclusions: We found an increased risk for subsequent fractures in the lower leg that requires inpatient care during childhood for boys, but not for girls, who were one to three years of age when they first suffered a femur shaft fracture. This increased fracture risk is probably not simply the result of greater risk-taking among boys. The explanation might relate to factors affecting the bone quality of the lower leg