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

Data from a pooled post hoc analysis of 14 placebo-controlled, dapagliflozin treatment studies in patients with type 2 diabetes with and without anemia at baseline

Dapagliflozin is a highly selective sodium-glucose cotransporter 2 inhibitor associated with stabilization of estimated glomerular filtration rate (eGFR); reductions in glycated hemoglobin (HbA1c), systolic blood pressure, body weight, and albuminuria; and a small and consistent increase in hematocrit [1], [2], [3], [4]. This data set is based on the associated article [5] analyzing data from 5325 patients with type 2 diabetes from 14 placebo-controlled, phase 3 (one phase 2/3), double-blind dapagliflozin treatment studies of 24-104 weeks' duration. Data on dapagliflozin's effects (vs. placebo) on hemoglobin (Hb), hematocrit, serum albumin, serum total protein concentrations, urine albumin/creatinine ratio, eGFR, heart rate, blood pressure, body weight, and safety in patients with type 2 diabetes with and without anemia were pooled and analyzed. Patients were divided into two groups according to baseline Hb levels: anemia (Hb 16.5 g/dL in men and >16.0 g/dL in women). Because anemia commonly occurs in patients with diabetes and chronic kidney disease [6], the data can be of value to further analyze trends in relevant physiological and pathophysiological parameters

Henoch-Schönlein purpura, patients admitted to Landspítali-University Hospital 1984-2000

Neðst á síðunni er hægt að nálgast greinina í heild sinni með því að smella á hlekkinn View/OpenObjective: Henoch-Schönlein purpura is a disease of small vessels which primarily affects children. The epidemiology of Henoch-Schönlein purpura in Iceland is not known. The main purpose of the study was to find out the incidence of the disease in Iceland and gather further epidemiological information. Patients and methods: All patients diagnosed with Henoch-Schönlein purpura during the years 1984-2000 and were admitted to the Children's Hospital Iceland, Landspítali Hringbraut as well as the paediatric department at the Landspítali Fossvogi were included in the study cohort. Information was gathered from medical records. The temporal relationship between the incidende of Henoch-Schönlein purpura and epidemics of three common infectious diseases was explored. Results: A total of 101 patients were found to have Henoch-Schönlein purpura, 51 females and 50 males. The incidence of Henoch-Schönlein purpura in Iceland is therefore approximately six cases annually. The mean age at diagnosis was 5.4 years. In addition to the rash, 72.3% had arthralgia and 45.5% abdominalia, 36.6% had hematuria or proteinuria during the hospitalization and 5.9% had severe renal involvement. The disease was more common in the winter months (Nov. - April) compared to the summer months (May - Oct.) (p=0.045). Conclusions: The epidemiology of Henoch-Schönlein purpura in Iceland is comparable to other countries. The disease was most common in children aged 2-5 years, which could reflect a common infection in the community as a part of the pathogenesis. Older children may have antibodies against these infections resulting in a decreased incidence of the disease. Our results support the theory that infection may play an important role in the pathogenesis of Henoch-Schönlein purpura. However, some abnormalities or variations in the immune response are probably also involved.Tilgangur: Henoch-Schönlein purpura er sjúkdómur sem einkennist af æðabólgu og kemur fyrst og fremst fram hjá börnum. Faraldsfræði Henoch-Schönlein purpura á Íslandi er ekki þekkt. Tilgangur rannsóknarinnar var því að kanna nýgengi sjúkdómsins á Íslandi auk þess að afla annarra faraldsfræðilegra upplýsinga. Sjúklingar og aðferðir: Allir sjúklingar 16 ára og yngri sem fengið höfðu greininguna Henoch-Schönlein purpura á tímabilinu 1984-2000 og voru lagðir inn á Barnaspítala Hringsins eða barnadeild Landspítala Fossvogi (áður SHR og Landakotsspítali) mynduðu rannsóknarhópinn. Safnað var upplýsingum úr sjúkraskrám um einkenni og rannsóknarniðurstöður. Sveiflur í tíðni sjúkdómsins voru bornar saman við sveiflur nokkurra þekktra smitsjúkdóma. Niðurstöður: Alls greindist 101 sjúklingur með Henoch-Schönlein purpura á tímabilinu, 51 stúlka og 50 drengir. Nýgengi Henoch-Schönlein purpura virðist svipað á Íslandi og víðast annars staðar, eða um sex tilfelli á ári. Meðalaldur var 5,4 ár. Auk útbrotanna reyndust 72,3% hafa liðverki og 45,5% kviðverki, 36,6% höfðu blóðmigu eða prótínmigu á meðan á sjúkrahúsvist stóð og 5,9% fengu alvarlegan nýrnasjúkdóm. Sjúkdómurinn var algengari á vetrarmánuðum (nóvember-apríl) en á sumarmánuðum (maí-október) (p= 0,045). Ályktanir: Faraldsfræði Henoch-Schönlein purpura hjá börnum á Íslandi virðist vera svipuð og í öðrum löndum. Áhugavert er að sjúkdómurinn er algengastur meðal barna tveggja til fimm ára og gæti það endurspeglað að algeng sýking eða sýkingar séu einn af orsakavöldum hans. Þegar börnin eldast og öðlast mótefni gegn slíkum sýkingum dregur úr tíðni sjúkdómsins. Mögulegt er að sýkingar séu einn þáttur í ferli sem ræsir sjúkdóminn en að auki þurfi ákveðin samsetning ónæmiskerfis að vera til staðar

Bacteremia in children with tumors or malignant diseases 1991-2000

Neðst á síðunni er hægt að nálgast greinina í heild sinni með því að smella á hlekkinn View/OpenIntroduction: Ten to twelve children with tumors or malignant diseases are diagnosed annually in Iceland. Cancer treatment can cause severe immune suppression, which makes the patients susceptible to serious infections. The aim of the current study was to evaluate sepsis in children with tumors or haematological malignancies, describe the types of bacteria cultured and their antibiotic susceptibilities, and collect information on associated risk factors. Materials and methods: This was a retrospective study on all children 0-15 years of age in Iceland who were diagnosed with a tumor or malignant disease between 1991 and 2000. Information was gathered on diagnosis, treatment, blood cultures, blood tests, antibiotic use, presence of foreign bodies (such as CVC) and survival. Results: Hundred-and-eighteen children were diagnosed with cancer or benign central nervous system (CNS) tumors in Iceland during the period 1991-2000. Central nervous system tumors were most common (N=28, 23.7%), leukemia (N=21, 17.8%) and lymphoma (N=17, 14%) were the second and third. The mean age at diagnosis was 5.9 years. Sufficient data was found in the hospital records on 99 children who were included in the study. Five hundred and twenty two blood cultures were drawn from 51 of the 99 children during the period. The mean number of blood cultures per patient was 14.8 for children with leukemia, but 2.6 for children with solid tumors. Of all blood cultures, 63.6% were from a central venous catheter or a Port-A Catheter , 5% from a peripheral site, but 30% were undisclosed. Of the 522 blood cultures, 90 grew bacteria (17.2%). Coagulase-negative staphylococci were isolated from 53 blood cultures (60%) and Staphylococcus aureus from 12 (13%). Positive cultures were regarded as a definite or possible infection in 47 blood cultures (52%), contamination in 17 (18.9% ), but uncertain in 26 (27.7%). Over 60 percent of the blood cultures (N=302) were drawn when a child was neutropenic (ANCInngangur: Árlega greinast 10-12 börn með æxli og illkynja sjúkdóma á Íslandi. Meðferð við illkynja sjúkdómum eykur hættu á alvarlegum sýkingum sem mikilvægt er að bregðast rétt við. Markmið rannsóknarinnar var að meta blóðsýkingar í börnum með æxli og illkynja sjúkdóma, þar með talið einstakar bakteríur og sýklalyfjanæmi þeirra. Áhættuþættir voru einnig kannaðir. Efniviður og aðferðir: Rannsóknin var aftur-skyggn og var rannsóknarþýðið öll börn á aldrinum 0-15 ára greind með illkynja sjúkdóm eða æxli á árunum 1991-2000 á Barnaspítala Hringsins. Upplýsingum var safnað um greiningu, meðferð, blóðræktanir, blóðgildi og fleira, svo sem sýklalyfjanotkun, aðskotahluti og afdrif. Niðurstöður: Alls greindust 118 börn með illkynja sjúkdóm eða æxli á tímabilinu. Æxli í miðtaugakerfi (MTK) voru algengust (N=28, 23,7%), þá hvítblæði (N=21, 17,8%) og eitlakrabbamein (N=17, 14%). Meðalaldur barna við greiningu var 5,9 ár. Upplýsingar úr sjúkraskrám voru fullnægjandi fyrir 99 börn. Af þeim var 51 barn blóðræktað. Fjöldi blóðræktana var 522. Meðalfjöldi blóðræktana var 14,8 hjá börnum með hvítblæði, en 2,6 hjá börnum með föst æxli. Blóðræktanir voru teknar úr holæðalegg eða lyfjabrunni í 63,6%, 5,4% úr útbláæð en 31% tilfella voru ótilgreind. Af 522 ræktunum voru 90 jákvæðar (17,2%). Algengasta bakterían var kóagúlasa-neikvæður stafýlókokkur (KNS) (N=53, 60%), en Staphylococcus aureus næstalgengastur (N=12, 13,3%). Jákvæð ræktun var talin tengjast líklegri eða sannaðri sýkingu í 47 tilfellum (52%), mengun í 17 (18,9%) en óvíst var með 26 ræktanir (27,7%). Barn hafði daufkyrningafæð (ANC ?1,0 *109/L) við 302 blóðræktanir (61,4%). Meðallengd daufkyrningafæðar var 9,0 dagar. C-reative protein (CRP) var að meðaltali 63,9 mg/L við blóðræktun og meðalhiti var 38,8 °C. Í 183 tilfellum var barn á sýklalyfjum við blóðræktun (35,1%). Rannsóknarniðurstöður barna með jákvæða blóðræktun voru ekki frábrugðnar öðrum. Ályktanir: Sýkingar af völdum Gram-jákvæðra baktería, sérstaklega KNS, eru nú mun algengari en Gram-neikvæðra baktería. Hluti jákvæðra ræktana getur þó verið mengun. Blóðrannsóknir virðast hafa lítið forspárgildi um niðurstöður blóðræktana. Ekkert barn lést úr blóðsýkingu af völdum baktería á tímabilinu. Reynslusýklalyfjameðferð hérlendis virðist enn árangursrík

Two serious eye injuries after tampering with fireworks

Neðst á síðunni er hægt að nálgast greinina í heild sinni með því að smella á hlekkinn Skoða/Opna(view/open)In this article we describe two separate cases of serious eye injuries that were the result of two teenagers´ attempts to make home-made explosives out of fireworks. They had tampered with the same brand of firework, Víti, that appears to be popular for this purpose and instructions are available on the internet. One boy got an intraocular glass splinter and underwent vitrectomy for removal. The other boy suffered burns on his corneas that were treated with amniotic membranes. In both cases the outcome was better than expected at first. The objective of this article is to draw attention to the danger of tampering with fireworks and the necessity of preventive measures to minimize the risk of serious eye injuries. Vilbergsson GR, Einarsdottir SO, Oskarsdottir SE, Olafsdottir E, Stefansson E. Two serious eye injuries after tampering with fireworks.Tveir unglingspiltar fengu meðferð á augndeild Landspítalans vegna alvarlegra augnáverka eftir fikt með heimatilbúnar sprengjur úr flugeldunum „Víti“ sem sprungu í höndunum á þeim. Annar pilturinn fékk glerflís inn í auga og þurfti glerhlaupsaðgerð til að fjarlægja flísina. Einnig fékk hann talsverða áverka á húð í andliti og á hendi. Hinn pilturinn brenndist illa á hornhimnu og í andliti. Hornhimnurnar voru meðhöndlaðar meðal annars með líknarbelgshimnu. Í báðum tilfellum fór betur en á horfðist. Tilgangur greinarinnar er að vekja athygli á hversu hættulegt fikt með flugelda getur verið. „Víti“ hefur verið vinsæll flugeldur til að fikta við og er auðvelt að finna leiðbeiningar á spjallrásum á veraldarvefnum. Æskilegt er að herða eftirlit með sölu flugelda og efla forvarnaraðgerðir, sérstaklega gagnvart börnum og unglingum

Condensation in nongeneric trees

We study nongeneric planar trees and prove the existence of a Gibbs measure on infinite trees obtained as a weak limit of the finite volume measures. It is shown that in the infinite volume limit there arises exactly one vertex of infinite degree and the rest of the tree is distributed like a subcritical Galton-Watson tree with mean offspring probability $m<1$. We calculate the rate of divergence of the degree of the highest order vertex of finite trees in the thermodynamic limit and show it goes like $(1-m)N$ where $N$ is the size of the tree. These trees have infinite spectral dimension with probability one but the spectral dimension calculated from the ensemble average of the generating function for return probabilities is given by $2\beta -2$ if the weight $w_n$ of a vertex of degree $n$ is asymptotic to $n^{-\beta}$.Comment: 57 pages, 14 figures. Minor change

Appearance of vertices of infinite order in a model of random trees

We study an equilibrium statistical mechanical model of tree graphs which are made up of a linear subgraph (the spine) to which leaves are attached. We prove that the model has two phases, a generic phase where the spine becomes infinitely long in the thermodynamic limit and all vertices have finite order and a condensed phase where the spine is finite with probability one and a single vertex of infinite order appears in the thermodynamic limit. We calculate the spectral dimension of the graphs in both phases and prove the existence of a Gibbs measure. We discuss generalizations of this model and the relationship with models of nongeneric random trees.Comment: 22 pages, 5 figure

The Norwegian Mother, Father, and Child cohort study (MoBa) genotyping data resource: MoBaPsychGen pipeline v.1

BACKRGROUND: The Norwegian Mother, Father, and Child Cohort Study (MoBa) is a population-based pregnancy cohort, which includes approximately 114,500 children, 95,200 mothers, and 75,200 fathers. Genotyping of MoBa has been conducted through multiple research projects, spanning several years; using varying selection criteria, genotyping arrays, and genotyping centres. MoBa contains numerous interrelated families, which necessitated the implementation of a family-based quality control (QC) pipeline that verifies and accounts for diverse types of relatedness. METHODS: The MoBaPsychGen pipeline, comprising pre-imputation QC, phasing, imputation, and post-imputation QC, was developed based on current best-practice protocols and implemented to account for the complex structure of the MoBa genotype data. The pipeline includes QC on both single nucleotide polymorphism (SNP) and individual level. Phasing and imputation were performed using the publicly available Haplotype Reference Consortium release 1.1 panel as a reference. Information from the Medical Birth Registry of Norway and MoBa questionnaires were used to identify biological sex, year of birth, reported parent-offspring (PO) relationships, and multiple births (only available in the offspring generation). RESULTS: In total, 207,569 unique individuals (90% of the unique individuals included in the study) and 6,981,748 SNPs passed the MoBaPsychGen pipeline. The relatedness checks performed throughout the pipeline allowed identification of within-generation and across-generation first-degree, second-degree, and third-degree relatives. The individuals passing post-imputation QC comprised 64,471 families ranging in size from singletons to 84 unique individuals (singletons are included as families as other family members may not have been genotyped, imputed, or passed post-imputation QC). The relationships identified include 287 monozygotic twin pairs, 22,884 full siblings, 117,004 PO pairs, 23,299 second-degree relative pairs, and 10,828 third-degree relative pairs. DISCUSSION: MoBa contains a highly complex relatedness structure, with a variety of family structures including singletons, PO duos, full (mother, father, child) PO trios, nuclear families, blended families, and extended families. The availability of robustly quality-controlled genetic data for such a large cohort with a unique extended family structure will allow many novel research questions to be addressed. Furthermore, the MoBaPsychGen pipeline has potential utility in similar cohorts