477 research outputs found
High temperature decreases the PIC / POC ratio and increases phosphorus requirements in <i>Coccolithus pelagicus</i> (Haptophyta)
Rising ocean temperatures will likely increase stratification of the water
column and reduce nutrient input into the photic zone. This will increase the
likelihood of nutrient limitation in marine microalgae, leading to changes in
the abundance and composition of phytoplankton communities, which in turn
will affect global biogeochemical cycles. Calcifying algae, such as
coccolithophores, influence the carbon cycle by fixing CO<sub>2</sub> into
particulate organic carbon through photosynthesis (POC production) and into
particulate inorganic carbon through calcification (PIC production). As
calcification produces a net release of CO<sub>2</sub>, the ratio of PIC to POC
production determines whether coccolithophores act as a source (high PIC / POC)
or a sink (low PIC / POC) of atmospheric CO<sub>2</sub>. We studied the effect of
phosphorus (P-) limitation and high temperature on the physiology and the
PIC / POC ratio of two subspecies of Coccolithus pelagicus. This large
and heavily calcified species is a major contributor to calcite export from
the photic zone into deep-sea reservoirs. Phosphorus limitation did not
influence exponential growth rates in either subspecies, but P-limited cells
had significantly lower cellular P-content. One of the subspecies was
subjected to a 5 °C temperature increase from 10 °C to
15 °C, which did not affect exponential growth rates either, but
nearly doubled cellular P-content under both high and low phosphate
availability. This temperature increase reduced the PIC / POC ratio by
40–60%, whereas the PIC / POC ratio did not differ between P-limited and
nutrient-replete cultures when the subspecies were grown near their
respective isolation temperature. Both P-limitation and elevated temperature
significantly increased coccolith malformations. Our results suggest that a
temperature increase may intensify P-limitation due to a higher P-requirement
to maintain growth and POC production rates, possibly reducing abundances in
a warmer ocean. Under such a scenario <i>C. pelagicus</i> may decrease its
calcification rate relative to photosynthesis, thus favouring
CO<sub>2</sub> sequestration over release. It seems unlikely that P-limitation by
itself causes changes in the PIC / POC ratio in this species
Overvåkning av Glomma, Vorma og Øyeren 2012
Høsten 2012 ble det tatt bunndyr- og begroingsprøver pÃ¥ fem stasjoner i Glomma og én i Vorma. I Øyeren ble det tatt prøver av planteplankton og vannkjemi. Gjennomsnittlig konsentrasjon av total fosfor og klorofyll a var henholdsvis 9.5 µg/l og 2.45 µg/l, tilsvarende svært god økologisk tilstand. Algesammensetningen viste et stort mangfold med lave konsentrasjonen av blÃ¥grønnalger. Ved Høyegga i Glomma ble det pÃ¥vist høye konsentrasjoner av kobber (6 prøver: 4.6-6.4 µg/l), tilsvarende sterkt forurenset tilstand (Klif 1997). PÃ¥ de fleste stasjonene i Glomma var det forholdsvis lave konsentrasjoner av suspenderte partikler (<0.8-4.3 mg/l), totalt fosfor (3-14 µg/l) og totalt nitrogen (200-555 µg/l). De høyeste konsentrasjonene ble pÃ¥vist pÃ¥ de nederste stasjonene. Basert pÃ¥ algeÂbegroing hadde de tre øverste stasjonene (Prestfoss, Gjølstadfoss, Bingsfoss) i Glomma svært god-, og de to nederste god tilstand (Solbergfoss, Sarpsfoss). Det var god økologisk tilstand ved Svanfoss i Vorma. Basert pÃ¥ bunndyrsamfunnet var den økologiske tilstanden pÃ¥ øverste stasjon svært god, moderat ved Solbergfoss og god pÃ¥ de øvrige. Den økologiske tilstanden ved Svanfoss var god. Det biologiske mangfoldet uttrykt som antall EPT-arter i bunnfaunaen varierte fra 18 ved Prestfoss til 10 ved Bingsfoss. Bunndyr og algebegroing viste samme tilstandsklasse pÃ¥ tre av seks stasjoner i 2012. PÃ¥ de øvrige stasjonene ga bunndyrindeksen en dÃ¥rligere tilstand. Basert pÃ¥ vannvegetasjonen karakteriseres undersøkte omrÃ¥der i Vorma som svært gode i forhold til eutrofiering.FM i Oslo og Akershus, Hedmark og Østfol
Impact of Antioxidant Feed and Growth Manipulation on the Redox Regulation of Atlantic Salmon Smolts
Accumulating evidence indicates a close relationship between oxidative stress and growth rate in fish. However, the underlying mechanisms of this relationship remain unclear. This study evaluated the combined effect of dietary antioxidants and growth hormone (GH) on the liver and the muscle redox status of Atlantic salmon. There were two sequential experimental phases (EP) termed EP1 and EP2, each lasting for 6 weeks. In EP1, Atlantic salmon were fed either low-(L, 230 mg/kg ascorbic acid (Asc), 120 mg/kg α-tocopherol (α-TOH)), or high-(H, 380 mg/kg Asc, 210 mg/kg α-TOH)vitamin diets. The vitamins were supplemented as stable forms and the feeding was continued in EP2. In EP2, half of the fish were implanted with 3 μL per g body weight of recombinant bovine GH (Posilac®, 1 mg rbGH g BW−1) suspended in sesame oil, while the other half were held in different tanks and sham-implanted with similar volumes of the sesame oil vehicle. Here, we show that increasing high levels of vitamin C and E (diet H) increased their content in muscle and liver during EP1. GH implantation decreased vitamin C and E levels in both liver and muscle but increased malondialdehyde (MDA) levels only in the liver. GH also affected many genes and pathways of antioxidant enzymes and the redox balance. Among the most consistent were the upregulation of genes coding for the NADPH oxidase family (NOXs) and downregulation of the oxidative stress response transcription factor, nuclear factor-erythroid 2-related factor 2 (nrf2), and its downstream target genes in the liver. We verified that GH increases the growth rate until the end of the trail and induces an oxidative effect in the liver and muscle of Atlantic salmon. Dietary antioxidants do lower oxidative stress but have no effect on the growth rate. The present study is intended as a starting point to understand the potential interactions between growth and redox signaling in fish.publishedVersio
Tissue Doppler echocardiographic quantification. Comparison to coronary angiography results in Acute Coronary Syndrome patients
BACKGROUND: Multiples indices have been described using tissue Doppler imaging (DTI) capabilities. The aim of this study was to assess the capability of one or several regional DTI parameters in separating control from ischemic myocardium. METHODS: Twenty-eight patients with acute myocardial infarction were imaged within 24-hour following an emergent coronary angioplasty. Seventeen controls without any coronary artery or myocardial disease were also explored. Global and regional left ventricular functions were assessed. High frame rate color DTI cineloop recordings were made in apical 4 and 2-chamber for subsequent analysis. Peak velocity during isovolumic contraction time (IVC), ejection time, isovolumic relaxation (IVR) and filling time were measured at the mitral annulus and the basal, mid and apical segments of each of the walls studied as well as peak systolic displacement and peak of strain. RESULTS: DTI-analysis enabled us to discriminate between the 3 populations (controls, inferior and anterior AMI). Even in non-ischemic segments, velocities and displacements were reduced in the 2 AMI populations. Peak systolic displacement was the best parameter to discriminate controls from AMI groups (wall by wall, p was systematically < 0.01). The combination IVC + and IVR< 1 discriminated ischemic from non-ischemic segments with 82% sensitivity and 85% specificity. CONCLUSION: DTI-analysis appears to be valuable in ischemic heart disease assessment. Its clinical impact remains to be established. However this simple index might really help in intensive care unit routine practice
Elevated productivity during Oceanic Anoxic Event 2 in the Mentelle Basin, Western Australia (IODP Expedition 369), indicated by benthic foraminifera and geochemical proxies
This is the author accepted manuscript. The final version is available from the Grzybowski FoundationBritish Geological Survey (BGS
Fatal poisoning in drug addicts in the Nordic countries in 2017
This study is the seventh report on fatal poisonings among drug addicts in the Nordic countries. In this report, we analyse data from the five Nordic countries: Denmark, Finland, Iceland, Norway and Sweden. Data on gender, number of deaths, places of deaths, age, main intoxicants and substances detected in blood were recorded to obtain national and comparable Nordic data, and to allow comparison with earlier studies conducted in 1984, 1991, 1997, 2002, 2007 and 2012. The death rate (number of deaths per 100,000 inhabitants) was highest in Iceland (6.58) followed closely by Sweden (6.46) and then lowest in Denmark (4.29). The death rate increased in Finland (5.84), Iceland and Sweden and decreased in Denmark compared to earlier studies. The death rate in Norway, which has decreased since 2002, has stabilised around 5.7 as of 2017. Women accounted for 7-23% of the fatal poisonings. The percentage was lowest in Iceland and highest in Finland and Norway. The age range was 14-70 years. The median age (41 years) was highest in Denmark and Norway. The other countries had a median age between 33 and 35 years. Opioids were the main cause of death. Methadone remained the main intoxicant in Denmark, while heroin/morphine was still the main intoxicant in Norway, as was buprenorphine in Finland. However, the picture has changed in Sweden compared to 2012, where heroin/morphine caused most deaths in 2017. Sweden also experienced the highest number of deaths from fentanyl analogues (67 deaths) and buprenorphine (61 deaths). Deaths from fentanyl analogues also occurred in Denmark, Finland and Norway, but to a smaller extent. Over the years, the proportion of opioid deaths has decreased in all countries except Sweden, which has experienced an increase. This decline has been replaced by deaths from CNS stimulants like cocaine, amphetamine and methylenedioxymethamphetamine (MDMA). Cocaine deaths have occurred in all countries but most frequently in Denmark. MDMA deaths have increased in all countries but mostly in Finland. Poly-drug use was widespread, as seen in the earlier studies. The median number of detected drugs per case varied from 4-6. Heroin/morphine, methadone, buprenorphine, cocaine, amphetamine, methamphetamine, MDMA, tetrahydrocannabinol (THC) and benzodiazepines were frequently detected. Pregabalin and gabapentin were detected in all countries, especially pregabalin, which was detected in 42% of the Finnish cases. New psychoactive substances (NPS) occurred in all countries except Iceland. (C) 2020 Elsevier B.V. All rights reserved.Peer reviewe
Indications for cardiovascular magnetic resonance in children with congenital and acquired heart disease: an expert consensus paper of the Imaging Working Group of the AEPC and the Cardiovascular Magnetic Resonance Section of the EACVI
This article provides expert opinion on the use of cardiovascular magnetic resonance (CMR) in young patients with congenital heart disease (CHD) and in specific clinical situations. As peculiar challenges apply to imaging children, paediatric aspects are repeatedly discussed. The first section of the paper addresses settings and techniques, including the basic sequences used in paediatric CMR, safety, and sedation. In the second section, the indication, application, and clinical relevance of CMR in the most frequent CHD are discussed in detail. In the current era of multimodality imaging, the strengths of CMR are compared with other imaging modalities. At the end of each chapter, a brief summary with expert consensus key points is provided. The recommendations provided are strongly clinically oriented. The paper addresses not only imagers performing CMR, but also clinical cardiologists who want to know which information can be obtained by CMR and how to integrate it in clinical decision-makin
Imaging in population science: cardiovascular magnetic resonance in 100,000 participants of UK Biobank - rationale, challenges and approaches
PMCID: PMC3668194SEP was directly funded by the National Institute for Health Research
Cardiovascular Biomedical Research Unit at Barts. SN acknowledges support
from the Oxford NIHR Biomedical Research Centre and from the Oxford
British Heart Foundation Centre of Research Excellence. SP and PL are
funded by a BHF Senior Clinical Research fellowship. RC is supported by a
BHF Research Chair and acknowledges the support of the Oxford BHF Centre
for Research Excellence and the MRC and Wellcome Trust. PMM gratefully
acknowledges training fellowships supporting his laboratory from the
Wellcome Trust, GlaxoSmithKline and the Medical Research Council
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