Giant cell arteritis : two cases with acute blindness

Neðst á síðunni er hægt að nálgast greinina í heild sinni með því að smella á hlekkinn Skoða/Opna(view/open)Giant cell arteritis is characterized primarily by inflammation in certain large and medium-sized arteries. The major risk factors are age, female gender and Northern European descent. In this report we describe two cases of acute vision loss due to giant cell arteritis. In both cases the erythrocyte sedimentation rate (ESR) was below 50 mm/hr and the presenting complaint was foggy vision followed by acute blindness. The cases are to some extent different, for example in the former case the patient reported jaw claudication and ophthalmologic evaluation was consistent with anterior ischemic optic neuropathy. In the latter case there was narrowing and box-carring of blood cells in retinal arterioles, consistent with occlusion of the central retinal artery. This patient had recently finished a 2-year long treatment with glucocorticosteroids for polymyalgia rheumatica. The retina and the optic nerve do not survive for long without perfusion. If giant cell arteritis causes blindness in one eye there is significant risk for the other eye to go blind if no treatment is given. Corticosteroids can spare the other eye and suppress the underlying inflammatory disease process as well. It is vital to confirm the diagnosis of giant cell arteritis with a biopsy and start corticosteroid treatment as soon as possible, even before the biopsy is taken.Risafrumuæðabólga einkennist af bólgubreytingum í ákveðnum stórum og meðalstórum slagæðum. Helstu áhættuþættir eru aldur, kvenkyn og norrænn uppruni. Í þessari grein er lýst tveimur tilfellum skyndiblindu af völdum risafrumuæðabólgu. Í báðum tilfellum mældist sökk undir 50 mm/klst og reyndist móðusýn fyrirboði blindu. Tilfellin eru ólík að mörgu leyti, til dæmis var í fyrra tilfellinu um að ræða kjálkaöng og lokun á æðum til fremsta hluta sjóntaugarinnar. Í seinna sjúkratilfellinu var lokun á aðalslagæðinni til sjónhimnu og hafði sá sjúklingur nýlokið tveggja ára barksterameðferð vegna fjölvöðvagigtar. Sjónhimna og sjóntaug lifa ekki af nema í stutta stund án blóðflæðis. Ef risafrumuæðabólga veldur blindu í öðru auga er hætta á að hitt augað missi sjón sé ekkert að gert. Barksterameðferð getur komið í veg fyrir blindu hins augans, auk þess að halda grunnsjúkdómnum niðri. Mikilvægt er að staðfesta risafrumuæðabólgu með vefjasýni og hefja barksterameðferð eins fljótt og kostur er, jafnvel áður en vefjasýni er tekið

Geochemistry and speciation of Fe(II) and Fe(III) in natural geothermal water, Iceland

The geochemistry of Fe(II) and Fe(III) was studied in natural geothermal waters in Iceland. Samples of surface and spring water and sub-boiling geothermal well water were collected and analyzed for Fe(II), Fe(III) and Fetotal concentrations. The samples had discharge temperatures in the range 27–99 °C, pH between 2.46 and 9.77 and total dissolved solids 155–1090 mg/L. The concentrations of Fe(II) and Fe(III) were determined in the <0.2 μm filtered and acidified fraction using a field-deployed ion chromatography spectrophotometry (IC-Vis) method within minutes to a few hours of sampling in order to prevent post-sampling changes. The concentrations of Fe(II) and Fe(III) were <0.1–130 μmoL/L and <0.2–42 μmoL/L, respectively. In-situ dialysis coupled with Fe(II) and Fe(III) determinations suggest that in some cases a significant fraction of Fe passing the standard <0.2 μm filtration method may be present in colloidal/particulate form. Therefore, such filter size may not truly represent the dissolved fraction of Fe but also nano-sized particles. The Fe(II) and Fe(III) speciation and Fetotal concentrations are largely influenced by the water pH, which in turn reflects the water type formed through various processes. In water having pH of ∼7–9, the total Fe concentrations were <2 μmoL/L with Fe(III) predominating. With decreasing pH, the total Fe concentrations increased with Fe(II) becoming increasingly important and predominating at pH < 3. In particular in waters having pH ∼6 and above, iron redox equilibrium may be approached with Fe(II) and Fe(III) possibly being controlled by equilibrium with respect to Fe minerals. In many acid waters, the Fe(II) and Fe(III) distribution may not have reached equilibrium and be controlled by the source(s), reaction kinetics or microbial reactions

Tracing olivine carbonation and serpentinization in CO2-rich fluids via magnesium exchange and isotopic fractionation

Chemical exchange between seawater and the oceanic crust is thought to play a significant role in the regulation of the global magnesium (Mg) cycle, yet relatively little is known about the rates and mechanisms of Mg exchange in these crustal environments. In this study we experimentally characterize the extent, and nature, of Mg isotope fractionation during the carbonation and serpentinization of olivine (one of the principal minerals found in ultramafic rocks) under hydrothermal conditions. Olivine alteration was found to be incongruent, with the reactant fluid composition varying according to the extent of olivine dissolution and the precipitation of secondary minerals. In mildly acid water (pH ∼ 6.5), olivine dissolved to form Mg-Fe carbonate solid solutions and minor chrysotile. Upon carbonation and a decrease of CO2 in the water, the pH increased to >8, with chrysotile and brucite becoming the dominant alteration minerals. The Mg-rich carbonates preferentially incorporated lighter Mg isotopes, resulting in a ∼0.5‰ increase of the δ26Mg composition of the fluid relative to olivine during the initial carbonation and serpentinization reactions. This was followed by a decrease in δ26Mg under higher pH conditions associated with the formation of brucite. Our experimental and modeling results therefore demonstrate that the δ26Mg composition of fluids involved in olivine alteration reflect the type and quantity of secondary Mg minerals formed, which in turn depend on the pH and CO2 concentration of the water. Comparison of these results with natural groundwaters and geothermal waters from basaltic terrains indicate that the δ26Mg composition of natural waters are likely to also be controlled by mafic rock dissolution and the preferential incorporation of isotopically light Mg into carbonates and isotopically heavy Mg into Mg-Si minerals. Together, these findings improve our understanding of Mg isotope systematics during water-rock interaction, and suggest that δ26Mg may be a useful tool for tracing reactions that are critical to geological CO2 sequestration

Chlorine isotope ratios record magmatic brine assimilation during rhyolite genesis

Publisher Copyright: © 2021 The Authors.Magmatic volatile phases within crustal silicic magma domains influence key volcanic processes such as the build up to eruptions and formation of magmatic-hydrothermal ore deposits. However, the extent and nature of fluid-melt interaction in such environments is poorly understood, as geochemical signals in volcanic rocks originating from pre-eruptive volatile processes are commonly overprinted by syn-eruptive degassing. Here, we use δ37Cl as a conservative tracer of brine-melt interaction on a broad suite of silicic volcanic rocks from Iceland. We find that the δ37Cl values of silicic rocks are systematically shifted to more negative values compared to associated basalts and intermediate rocks by up to 2.9 . These large shifts cannot be explained by well known processes inherent to silicic magma genesis, including crustal assimilation, mineral-melt fractionation and syn-eruptive degassing. Instead, we show that low δ37Cl values in silicic rocks can be attributed to assimilation of magmatic brines that are formed and stored in long lived crustal magma mushes. Our results indicate that magmatic brine assimilation is a fundamental, but previously unrecognised part of rhyolite genesis.Peer reviewe

In situ probing of the present-day zircon-bearing magma chamber at Krafla, Northeastern Iceland

Active felsic magmatism has been rarely probed in situ by drilling but one recent exception is quenched rhyolite sampled during the 2009 Iceland Deep Drilling Project (IDDP). We report finding of rare zircons of up to ∼100 µm in size in rhyolite glasses from the IDDP-1 well products and the host 1724 AD Viti granophyres. The applied SHRIMP U-Th dating for both the IDDP and the Viti granophyre zircons gives zero-age (±2 kyr), and therefore suggests that the IDDP-1 zircons have crystallized from an active magma intrusion rather than due to the 20–80 ka post-caldera magmatic episodes recorded by nearby domes and ridges. Ti-in-zircon geothermometer for Viti granophyre reveals zircon crystallization temperatures ∼800°C–900°C, whereas IDDP-1 rhyolite zircon cores show Ti content higher than 100 ppm, corresponding to temperatures up to ∼1,100°C according to the Ti-in-zircon thermometer. According to our thermochemical model at such elevated temperatures as 1,100°C, rhyolitic magma cannot be saturated with zircon and zircon crystallization is not possible. We explain this controversy by either kinetic effects or non-ideal Ti incorporation into growing zircons at low pressures that start to grow from nucleus at temperatures ∼930°C. High temperatures recorded by IDDP-1 zircon together with an occurrence of baddeleyite require that the rhyolite magma formed by partial melting of the host granophyre due to basaltic magma intrusion. Zr concentration profiles in glass around zircons are flat, suggesting residence in rhyolitic melt for &gt;4 years. In our thermochemical modeling, three scenarios are considered. The host felsite rocks are intruded by: 1) a basaltic sill, 2) rhyolite magma 3) rhyolite sill connected to a deeper magmatic system. Based on the solution of the heat conduction equation accounting for the release of latent heat and effective thermal conductivity, these data confirm that the rhyolite magma could be produced by felsic crust melting as a result of injection of a basaltic or rhyolite sill during the Krafla Fires eruption (1975 AD)

SUSTAIN drilling at Surtsey volcano, Iceland, tracks hydrothermal and microbiological interactions in basalt 50 years after eruption

The 2017 Surtsey Underwater volcanic System for Thermophiles, Alteration processes and INnovative concretes (SUSTAIN) drilling project at Surtsey volcano, sponsored in part by the International Continental Scientific Drilling Program (ICDP), provides precise observations of the hydrothermal, geochemical, geomagnetic, and microbiological changes that have occurred in basaltic tephra and minor intrusions since explosive and effusive eruptions produced the oceanic island in 1963–1967. Two vertically cored boreholes, to 152 and 192 m below the surface, were drilled using filtered, UV-sterilized seawater circulating fluid to minimize microbial contamination. These cores parallel a 181 m core drilled in 1979. Introductory investigations indicate changes in material properties and whole-rock compositions over the past 38 years. A Surtsey subsurface observatory installed to 181 m in one vertical borehole holds incubation experiments that monitor in situ mineralogical and microbial alteration processes at 25–124 ∘C. A third cored borehole, inclined 55∘ in a 264∘ azimuthal direction to 354 m measured depth, provides further insights into eruption processes, including the presence of a diatreme that extends at least 100 m into the seafloor beneath the Surtur crater. The SUSTAIN project provides the first time-lapse drilling record into a very young oceanic basaltic volcano over a range of temperatures, 25–141 ∘C from 1979 to 2017, and subaerial and submarine hydrothermal fluid compositions. Rigorous procedures undertaken during the drilling operation protected the sensitive environment of the Surtsey Natural Preserve

Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples

Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts

Kynjaskipt íþróttakennsla í grunnskólum

Hreyfing er vopn gegn kyrrsetu og offitu auk þess sem hún minnkar líkur á þunglyndi og depurð. Jákvæð upplifun af íþróttakennslu í skólum getur lagt grunn að heilsusamlegu líferni nemenda. Góð og markviss kennsla getur styrkt stoðkerfi líkamans og bætt líkamsreisn. Það er því ljóst að góð íþróttakennsla er gríðarlega mikilvæg fyrir börn og unglinga þar sem hún getur aukið vellíðan og kraft. Íþróttakennsla er tiltölulega ung á Íslandi og því eðlilegt að hún sé enn í mikilli framför. Skólar fá mikið frjálsræði til að hafa íþróttakennsluna eftir sínu höfði, en skylda er að veita hverjum nemanda þrjá íþróttatíma í hverri skólaviku yfir skólaárið. Með því að kanna hvort kynjaskipt íþróttakennsla hafi áhrif á virkni nemenda í íþróttakennslu er hægt að sjá hvort hún sé að einhverju leyti nauðsynleg. Markmið könnunarinnar var að leita svara við kostum kynjaskiptrar íþróttakennslu, hvort hún sé nauðsynleg í skólum, hvort íþróttafræðingarnir séu sáttir með kerfið sem þeirra skóli notar og hvaða kerfi sé réttast að nota í íþróttakennslu. Til að fá svar við þessum spurningum voru tekin viðtöl við þrjá íþróttafræðinga. Niðurstöður könnunarinnar sýndu fram á að kynjaskipting sé nauðsynleg að einhverju leyti í íþróttakennslu grunnskóla, þá sérstaklega í efstu bekkjunum. Hún virkar mjög vel í greinum sem innihalda keppni og líkamlega snertingu, t.d. boltagreinum. Erfitt var að túlka niðurstöðurnar um hvaða kerfi stuðli að sem bestri virkni í allri íþróttakennslu. Erfitt er að alhæfa út frá þessum niðurstöðum þar sem úrtakið er mjög lítið. Fróðlegt væri að gera stóra rannsókn meðal íþróttafræðinga til að sjá þannig betur almennt álit íþróttafræðinga til kynjaskiptrar íþróttakennslu, hvort íþróttafræðingar séu sáttir með kerfi skólans síns og í hvernig kerfi þeir vildu helst starfa innan síns skóla

Verðmætasköpun úr affalli og útblæstri jarðvarmavirkjana. Greining á viðskiptahugmynd í samstarfi við geoSilica Iceland ehf.: Heilsudrykkur úr affallsvatni.

Umfjöllunarefni þessarar ritgerðar er verðmætasköpun úr affalli og útblæstri íslenskra jarðvarmavirkjana. Í stað þess að líta á affallsvatn og útblástur sem mengun og kostnað má nýta það til ýmissar framleiðslu eða ræktunar. Bætt nýting jarðhitaauðlindarinnar stuðlar jafnframt að aukinni samkeppnishæfni og sjálfbærni hennar auk þess að skapa verðmæti og störf. Í ritgerðinni er heildarumfang losunar á affallsvatni (skiljuvatni, þéttivatni og kælivatni) og útblæstri óþéttanlegra lofttegunda skoðað eftir virkjunum, en frá þeim sex jarðvarmavirkjunum sem starfræktar voru á árinu 2011 losuðust alls 206 milljón tonn af affallsvatni og 212 þúsund tonn af útblæstri. Einnig er gerð grein fyrir þekktum og minna þekktum aðferðum við nýtingu affallsvatns og útblásturs auk þess sem aðstæður til nýtingar affallstraumanna eru skoðaðar. Sveitarfélög hafa síðustu ár tekið frá lóðir í nágrenni jarðvarmavirkjana fyrir orkutengdan iðnað, þ.m.t. iðnað sem nýtir affallsvatn og útblástur virkjana. Alls hafa sveitarfélög tekið frá yfir 1.000 ha fyrir orkutengdan iðnað til viðbótar við iðnaðarsvæði sem sérstaklega eru skilgreind sem orkuvinnslusvæði í aðalskipulögum. Í lok ritgerðarinnar er viðskiptaáætlun sem unnin var fyrir sprotafyrirtækið geoSilica Iceland ehf. Þar er sýnt fram á raunhæfi þess að framleiða kísilríkan heilsudrykk úr skiljuvatni Hellisheiðarvirkjunar á arðbæran hátt.The topic of this thesis is value creation from wastewater and exhaust from Icelandic geothermal power plants. Wastewater and exhaust can be utilized in various production or cultivation instead of being disposed at high cost. The utilization results in more effective use of the geothermal resources and thereby increased competitiveness and sustainability of the resource in addition to creating value and jobs. This thesis outlines the scope of wastewater (separator water, condensate and cooling water) and exhaust, of non-condensable gases, overall discharge. In 2011, 206 million tons of wastewater and 212 thousand tons of exhaust were discharged by the six operating power plants. It also outlines known and lesser known utilization processes of wastewater and exhaust, and reviews conditions for utilization. In recent years municipalities have organized and allocated land for geothermal energy-related industries in the vicinity of geothermal power plants. In total municipalities have allocated over 1.000 ha of land for that purpose. At the end of this thesis production of a silica rich mineral drink from Hellisheiði power plant's separation water is demonstrated viable in a business plan. The business plan was made for and in cooperation with the start-up company geoSilica Iceland ehf.Orkurannsóknarsjóður LandsvirkjunarHluti II er sjötti kafli ritgerðarinnar og jafnframt viðskiptaáætlun. Til að vernda viðkvæmar upplýsingar er hlutinn ekki ætlaður til opinberrar birtingar