University of Iceland

About: University of Iceland is a education organization based out in Reykjavik, Suðurnes, Iceland. It is known for research contribution in the topics: Population & Genome-wide association study. The organization has 5423 authors who have published 16199 publications receiving 694762 citations. The organization is also known as: Háskóli Íslands.

Electronegativity of low-pressure high-density oxygen discharges

Abstract: We use a global (volume averaged) model to study the presence of negative ions and metastable species in low-pressure high-density oxygen discharges. We find the negative oxygen ion O- to be the dominant negative ion in the discharge, the density of the negative ion O2- to be small and the density of the negative ion O-3 to be negligible in the pressure range of interest, 1-100?mTorr. Dissociative attachment of the oxygen molecule in the ground-state O2(3?g-) and the metastable oxygen molecule O2(a1?g) are the dominating channels for the creation of the negative oxygen ion O-. At low pressure (<5?mTorr) recombination involving O- and O+ ions is the main loss channel for O- ions. At higher pressure, the detachment on O(3P) becomes the main loss channel for the O- ion. The creation of O-2 is mainly through dissociative attachment of ozone O3. Ozone is almost entirely created through detachment by the collision of O- with the metastable oxygen molecule O2(a1?g). The creation of O-2 is thus greatly influenced by this detachment process and neglecting the detachment has a significant influence on the density of O-2 ions. At low pressure (<10?mTorr) the O-2 ion is mainly lost through recombination while at higher pressure the charge transfer to form O2 is the dominating loss process.

Antimicrobial activity of lipids added to human milk, infant formula, and bovine milk.

Abstract: Lipids previously shown to have antiviral and antibacterial activity in buffers were added to human milk, bovine milk, and infant formulas to determine whether increased protection from infection could be provided to infants as part of their diet. Fatty acids and monoglycerides with chain lengths varying from 8 to 12 carbons were found to be more strongly antiviral and antibacterial when added to milk and formula than long chain monoglycerides. Lipids added to milk and formula inactivated a number of pathogens including respiratory syncytial virus (RSV), herpes simplex virus type 1 (HSV-1), Haemophilus influenzae, and Group B streptococcus. The results presented in this study suggest that increased protection from infection may be provided to infants at mucosal surfaces, prior to the digestion of milk and formula triglycerides, by the addition of antimicrobial medium chain monoglycerides to an infant's diet.

Vertebral bone marrow fat associated with lower trabecular BMD and prevalent vertebral fracture in older adults.

Abstract: Context: Bone marrow fat (BMF) and bone mineral density (BMD) by dual x-ray energy absorptiometry (DXA) are negatively correlated. However, little is known about the association of BMF with fracture or with separate trabecular and cortical bone compartments. Objective: Our objective was to assess the relationships between vertebral BMF, BMD by quantitative computed tomography, and fracture in older adults. Design, Setting, and Participants: We conducted a cross-sectional study in the Age Gene/Environment Susceptibility-Reykjavik cohort. Main Outcome Measures: Outcomes measures included vertebral BMF (L1–L4) measured with magnetic resonance spectroscopy, quantitative computed tomography and DXA scans of the hip and spine, and DXA vertebral fracture assessments. Previous clinical fracture was determined from medical records. Results: In 257 participants without recent bone-active medication use, mean age was 79 (SD 3.1) years. Mean BMF was 53.5% ± 8.1% in men and 55.0% ± 8.4% in women. Those with prevalent ...

Large-scale analysis of association between GDF5 and FRZB variants and osteoarthritis of the hip, knee, and hand

Abstract: Primary osteoarthritis (OA) is the most prevalent articular disorder and accounts for substantial morbidity and disability, particularly among the elderly, with a considerable health care burden in the developed countries. Its etiology is multifactorial. Many common genetic variants have been proposed as being associated with the risk of OA, albeit with inconsistent results among studies. Among them, 2 genes that have received extensive attention in the recent literature are the growth differentiation factor 5 gene (GDF5) and the Frizzled-related protein gene (FRZB). GDF5 has a role in the development and maintenance of bone and cartilage (1–5). FRZB is a key participant in the Wnt signaling pathway, which has been considered to be important in OA since it can influence chondrocyte differentiation and cartilage function (6–8). With regard to GDF5, Miyamoto et al reported a strong association between the single-nucleotide polymorphism (SNP) rs143383 and hip and knee OA in Asian populations (9): the per–risk allele (T) summary odds ratio (OR) was 1.79 (P = 1.8 × 10−13) in 2 Japanese cohorts evaluated for associations with hip OA, and the ORs obtained in a Japanese and a Chinese cohort evaluated for associations with knee OA were 1.30 (P = 0.0021) and 1.54 (P = 2.8 × 10−4), respectively. Several studies of Caucasian populations have yielded conflicting results (10,11). Findings of an earlier meta-analysis (12) suggested that rs143383 is associated with a 1.21-fold increase in the risk of knee OA per risk allele copy, but significance levels were modest by current standards (P = 0.0004 in the per-allele model). A modest association was also observed for all cases combined (any joint involved [P = 0.006]); however, a large heterogeneity was observed (I2 = 85%). Several studies have also investigated the relationship between OA and 2 polymorphisms in FRZB, rs7775 and rs288326 (7,13,14). Much like the findings with GDF5, studies have yielded conflicting results (13–17). A preliminary meta-analysis of published data showed no clear evidence of association between the rs7775 SNP and hip or knee OA (18). The original proposed association was stronger at the haplotype level (7), but published data did not enable evaluation of haplotype effects. The inconclusive and conflicting results leave uncertainty with regard to the effects of these polymorphisms. Single studies are hampered by small sample size and lack of power (19), inconsistent definitions of OA phenotypes, difficulty in assessing haplotypes, lack of standardization, and potentially selective reporting in the published literature (20). Meta-analyses based on consortia may help overcome some of these limitations. Herein we report the results of a collaborative meta-analysis of individual-level data, from 14 teams, on the relationship of the GDF5 rs143383, FRZB rs7775, and FRZB rs288326 polymorphisms with OA phenotypes. We synthesized standardized data on hip, knee, and hand OA according to a common meta-analysis protocol.

Nature, Power, and Growth

Abstract: This essay reviews the relationship between natural-resource abundance and economic growth around the world, and presents some new results. The principal reasons why resource-based production can inhibit economic growth over long periods are traced to the Dutch disease, neglect of education, rent seeking, and economic policy failures. Across a large number of countries in the period from 1965 to 1998, the share of the primary sector in the labour force is shown to be inversely related to exports, domestic and foreign investment, and education, and directly related to external debt, import protection, corruption, and income inequality. The cross-sectional data show, moreover, that the share of the primary sector in the labour force is inversely related to per capita growth across countries. None of this lies in the nature of things, however. What seems to matter for economic growth is not the abundance of natural resources per se, but rather the quality of their management, and of economic management and institutions in general.