Sökning: "Per Roos"

Visar resultat 1 - 5 av 11 avhandlingar innehållade orden Per Roos.

  1. 1. 231Pa and Th isotopes as tracers of deep water ventilation and scavenging in the Mediterranean Sea

    Författare :Sandra Gdaniec; Carl-MAgnus Mörth; Per Andersson; Helen Coxall; Per Roos; Carl-Magnus Mörth; Per Anerson; Matthieu Roy-Barman; Stockholms universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; 231Pa; 230Th; 232Th; Mediterranean Sea; scavenging; deep water ventilation; geokemi; Geochemistry; Protactinium; Thorium; particle transport; deep water circulation;

    Sammanfattning : The naturally occurring isotopes 231Pa and 230Th are used as tracers of marine biogeochemical processes. They are both produced from the radioactive decay of their uniformly distributed uranium parents (235U and 234U) in seawater. LÄS MER

  2. 2. Studies of actinides in a superanoxic fjord

    Författare :Per Roos; Lund Medicinsk strålningsfysik; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Geology; colloids.; TIMS; pore water; remobilisation; sediments; ultrafiltration; uranium; thorium; americium; plutonium; Anoxic; Framvaren; fjord; physical geography; Geologi; fysisk geografi;

    Sammanfattning : Water column and sediment profiles of plutonium, americium, thorium and uranium have been obtained in the superanoxic Framvaren fjord, southern Norway. The concentrations of bomb test fallout Pu, Am as well as 'dissolved' Th in the bottom water are the highest recorded in the marine environment. LÄS MER

  3. 3. Studies on metals in motor neuron disease

    Författare :Per M. Roos; Karolinska Institutet; Karolinska Institutet; []
    Nyckelord :MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP;

    Sammanfattning : A slow but steady increase in neurodegenerative disorders has been noted in recent decades. Degenerations in the nervous system are found in Alzheimer´s disease, Parkinson´s disease and motor neuron diseases. Amyotrophic lateral sclerosis (ALS) is the most common of the motor neuron diseases. LÄS MER

  4. 4. Manganese and Iron Heterodimers and Homodimers in Enzymes : Insights from Density Functional Theory

    Författare :Katarina Roos; Per Siegbahn; Margareta R. A. Blomberg; Frank Neese; Stockholms universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; NATURAL SCIENCES; Ribonucleotide reductase; manganese; iron; density functional theory; kemisk fysik; Chemical Physics;

    Sammanfattning : The enzyme ribonucleotide reductase (RNR) catalyzes the reduction of ribonucleotides to deoxyribonucleotides, the building blocks of DNA, and is essential for all organisms. Canonical class I RNR R2 proteins use a diiron cofactor to generate a tyrosyl radical, which is required for catalysis. LÄS MER

  5. 5. Iodine Isotopes and their Species in Surface Water from the North Sea to the Northeastern Atlantic Ocean

    Författare :Peng He; Ala Aldahan; Per Roos; Uppsala universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; iodine isotopes; 129I; 127I; oceans; North Sea; speciation; Atlantic Ocean; English Channel; Celtic Sea; AMS; iodine chemistry; geochemistry; Earth Science with specialization in Environmental Analysis; Geovetenskap med inriktning mot miljöanalys;

    Sammanfattning : Huge amounts of anthropogenic 129I have been and still are released to the environment through liquid and gaseous discharges from the nuclear fuel reprocessing facilities worldwide and in particular the ones in Europe. Most of this 129I signal has been accumulated in the marine environment which plays a major role in the iodine natural pool. LÄS MER