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Possnert, Göran
Alternative names
Publications (10 of 244) Show all publications
Landsverk, O. J. B., Snir, O., Casado, R. B., Richter, L., Mold, J. E., Reu, P., . . . Jahnsen, F. L. (2017). Antibody-secreting plasma cells persist for decades in human intestine. Journal of Experimental Medicine, 214(2), 309-317.
Open this publication in new window or tab >>Antibody-secreting plasma cells persist for decades in human intestine
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2017 (English)In: Journal of Experimental Medicine, ISSN 0022-1007, E-ISSN 1540-9538, Vol. 214, no 2, 309-317 p.Article in journal (Refereed) Published
Abstract [en]

Plasma cells (PCs) produce antibodies that mediate immunity after infection or vaccination. In contrast to PCs in the bone marrow, PCs in the gut have been considered short lived. In this study, we studied PC dynamics in the human small intestine by cell-turnover analysis in organ transplants and by retrospective cell birth dating measuring carbon-14 in genomic DNA. We identified three distinct PC subsets: a CD19(+) PC subset was dynamically exchanged, whereas of two CD19(-) PC subsets, CD45(+) PCs exhibited little and CD45(-) PCs no replacement and had a median age of 11 and 22 yr, respectively. Accumulation of CD45(-) PCs during ageing and the presence of rotavirus-specific clones entirely within the CD19(-) PC subsets support selection and maintenance of protective PCs for life in human intestine.

Place, publisher, year, edition, pages
NewYork, USA: , 2017
National Category
Biophysics Immunology in the medical area
Research subject
Physics with specialization in Ion Physics
Identifiers
urn:nbn:se:uu:diva-317759 (URN)10.1084/jem.20161590 (DOI)000394251400004 ()28104812 (PubMedID)
Projects
The Human Regenerative Map
Funder
Swedish Research CouncilSwedish Cancer SocietyThe Karolinska Institutet's Research FoundationKnut and Alice Wallenberg FoundationTorsten Söderbergs stiftelse
Available from: 2017-03-17 Created: 2017-03-17 Last updated: 2018-01-13Bibliographically approved
Chen, P., Yu, Z. B., Aldahan, A., Yi, P., Possnert, G. & Mugwaneza, V. d. (2017). Comparison of measurement and modeling results of the global Be-10 flux in topsoil. Journal of Radioanalytical and Nuclear Chemistry, 311(3), 2039-2045.
Open this publication in new window or tab >>Comparison of measurement and modeling results of the global Be-10 flux in topsoil
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2017 (English)In: Journal of Radioanalytical and Nuclear Chemistry, ISSN 0236-5731, E-ISSN 1588-2780, Vol. 311, no 3, 2039-2045 p.Article in journal (Refereed) Published
Abstract [en]

Soils are among the major terrestrial reservoirs of atmospheric Be-10 isotope and provide information of landscape evolution history. Despite this importance, there is no overview of the global soil Be-10 fluxes in topsoil that is linked with atmospheric flux models. A comparison between measured (in topsoil) and atmospherically modeled Be-10 fluxes is presented here. The data show relatively good agreement in the latitudinal trends. This feature demonstrates the potential to use the modeling data in estimating soil development/erosion rates in large scale basins where extensive Be-10 measurements can be limited.

Place, publisher, year, edition, pages
Springer, 2017
Keyword
Be-10 flux, Atmosphere, Global, Landscape, Topsoil
National Category
Physical Geography
Identifiers
urn:nbn:se:uu:diva-320282 (URN)10.1007/s10967-017-5171-8 (DOI)000398027800055 ()
Available from: 2017-04-25 Created: 2017-04-25 Last updated: 2018-01-13Bibliographically approved
Suteerasak, T., Elming, S.-Å., Possnert, G., Ingri, J. & Widerlund, A. (2017). Deposition rates and C-14 apparent ages of Holocene sediments in the Bothnian Bay of the Gulf of Bothnia using paleomagnetic dating as a reference. Marine Geology, 383, 1-13.
Open this publication in new window or tab >>Deposition rates and C-14 apparent ages of Holocene sediments in the Bothnian Bay of the Gulf of Bothnia using paleomagnetic dating as a reference
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2017 (English)In: Marine Geology, ISSN 0025-3227, E-ISSN 1872-6151, Vol. 383, 1-13 p.Article in journal (Refereed) Published
Abstract [en]

Three 6-m-long cores of sediments were collected in the northern, middle and southern part of the Bothnian Bay. The sediments were dated by paleomagnetic dating techniques, constrained by magnetic properties and geochemical data. The results indicate the ages of the sediments in the bottom part of the cores in the northern, middle and southern parts of the Bothnian Bay to be approximately 5300 years BP, 5350 years BP and 3500 years BP, respectively. The deposition rate calculated from the estimated ages at various depths show that the deposition rate was generally in the range 0.5-1.5 mm/year but it was higher in the southern part than in the middle and northern parts of the bay. There was a significant increase in the deposition rate at ca 2200 years BP, recorded in all three cores, a rate varying between 2.47 and 3.07 mm/year and lasting until ca 1840 years BP. A proposed constant uplift rate of the crust during the period ca 5500 years BP to present is thus not reflected by a constant deposition rate. The peaks in deposition rates at ca 2200-1840 years BP were followed by a decrease in salinity. This phenomenon is suggested to be caused by crustal uplift, with a threshold being formed in the southern part of the bay, thereby increasing the reactivation of bottom sediments and reducing the inflow of brackish water from the Bothnian Sea. The C-14 ages of the sediments reveal differences in age compared with the paleomagnetic ages. In the southern core, the C-14 ages are ca 1350 years older, and in the north, the age offset is mixed. The reactivation and re-deposition of sediments is argued to be the reason for the apparent C-14 age differences. This finding demonstrates that C-14 cannot be used for the dating of Bothnian Bay sediments unless the radiocarbon age offset has been determined.

Keyword
Bothnian Bay, Holocene sediments, Paleomagnetism, C-14 dating, Deposition rate, Radiocarbon age offset
National Category
Geosciences, Multidisciplinary
Identifiers
urn:nbn:se:uu:diva-316961 (URN)10.1016/j.margeo.2016.10.009 (DOI)000392786800001 ()
Funder
Swedish Research CouncilThe Geological Survey of Sweden (SGU)
Available from: 2017-03-08 Created: 2017-03-08 Last updated: 2017-11-29Bibliographically approved
Spalding, K. L., Bernard, S., Näslund, E., Salehpour, M., Possnert, G., Appelsved, L., . . . Arner, P. (2017). Impact of fat mass and distribution on lipid turnover in human adipose tissue. Nature Communications, 8, Article ID 15253.
Open this publication in new window or tab >>Impact of fat mass and distribution on lipid turnover in human adipose tissue
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2017 (English)In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 8, 15253Article in journal (Refereed) Published
Abstract [en]

Differences in white adipose tissue (WAT) lipid turnover between the visceral (vWAT) and subcutaneous (sWAT) depots may cause metabolic complications in obesity. Here we compare triglyceride age and, thereby, triglyceride turnover in vWAT and sWAT biopsies from 346 individuals and find that subcutaneous triglyceride age and storage capacity are increased in overweight or obese individuals. Visceral triglyceride age is only increased in excessively obese individuals and associated with a lower lipid removal capacity. Thus, although triglyceride storage capacity in sWAT is higher than in vWAT, the former plateaus at substantially lower levels of excess WAT mass than vWAT. In individuals with central or visceral obesity, lipid turnover is selectively increased in vWAT. Obese individuals classified as 'metabolically unhealthy' (according to ATPIII criteria) who have small subcutaneous adipocytes exhibit reduced triglyceride turnover. We conclude that excess WAT results in depot-specific differences in lipid turnover and increased turnover in vWAT and/or decreased turnover in sWAT may result in metabolic complications of overweight or obesity.

National Category
Medical Biotechnology (with a focus on Cell Biology (including Stem Cell Biology), Molecular Biology, Microbiology, Biochemistry or Biopharmacy)
Identifiers
urn:nbn:se:uu:diva-325697 (URN)10.1038/ncomms15253 (DOI)000401831600001 ()28534500 (PubMedID)
Funder
EU, European Research CouncilSwedish Research CouncilNovo Nordisk, NNF15CC0018486
Available from: 2017-06-27 Created: 2017-06-27 Last updated: 2017-11-29Bibliographically approved
Xing, S., Hou, X., Aldahan, A. & Possnert, G. (2017). Speciation analysis of I-129 in seawater using coprecipitation and accelerator mass spectrometry and its applications. Journal of Radioanalytical and Nuclear Chemistry, 311(1), 833-841.
Open this publication in new window or tab >>Speciation analysis of I-129 in seawater using coprecipitation and accelerator mass spectrometry and its applications
2017 (English)In: Journal of Radioanalytical and Nuclear Chemistry, ISSN 0236-5731, E-ISSN 1588-2780, Vol. 311, no 1, 833-841 p.Article in journal (Refereed) Published
Abstract [en]

Speciation analysis of long-lived I-129 in seawater can provide useful information on the source of water masses. This paper presents an improved method for speciation analysis of I-129 based on coprecipitation of iodide as AgI with Ag2SO3 and AgCl. By adding a small amount of I-127 carrier, the separation efficiency of iodine species and the accuracy and precision of I-129 measurement are remarkably improved. I-129 species in depth profiles of seawater from the Antarctic were analyzed for investigation of water circulation in the Antarctic.

Keyword
I-129, Speciation analysis, Accelerator mass spectrometry, Seawater
National Category
Analytical Chemistry
Identifiers
urn:nbn:se:uu:diva-315844 (URN)10.1007/s10967-016-5060-6 (DOI)000392075200089 ()
Funder
Swedish Polar Research Secretariat
Available from: 2017-02-21 Created: 2017-02-21 Last updated: 2017-11-29Bibliographically approved
Reu, P., Khosravi, A., Bernard, S., Mold, J. E., Salehpour, M., Alkass, K., . . . Frisen, J. (2017). The Lifespan and Turnover of Microglia in the Human Brain. Cell reports, 20(4), 779-784.
Open this publication in new window or tab >>The Lifespan and Turnover of Microglia in the Human Brain
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2017 (English)In: Cell reports, ISSN 2211-1247, E-ISSN 2211-1247, Vol. 20, no 4, 779-784 p.Article in journal (Refereed) Published
Abstract [en]

The hematopoietic system seeds the CNS with microglial progenitor cells during the fetal period, but the subsequent cell generation dynamics and maintenance of this population have been poorly understood. We report that microglia, unlike most other hematopoietic lineages, renew slowly at a median rate of 28% per year, and some microglia last for more than two decades. Furthermore, we find no evidence for the existence of a substantial population of quiescent long-lived cells, meaning that the microglia population in the human brain is sustained by continuous slow turnover throughout adult life.

Place, publisher, year, edition, pages
Cambridge, MA 02139, USA: , 2017
Keyword
Cell turnover, regeneration, microglia, human brain
National Category
Biophysics Cell Biology
Research subject
Ion Physics; Biology with specialization in Molecular Cell Biology
Identifiers
urn:nbn:se:uu:diva-328314 (URN)10.1016/j.celrep.2017.07.004 (DOI)000406198900002 ()28746864 (PubMedID)
Projects
The Human Regeneration Map
Available from: 2017-08-21 Created: 2017-08-21 Last updated: 2017-11-29Bibliographically approved
Xing, S., Hou, X., Aldahan, A., Possnert, G., Shi, K., Yi, P. & Zhou, W. (2017). Water Circulation and Marine Environment in the Antarctic Traced by Speciation of I-129 and I-127. Scientific Reports, 7, Article ID 7726.
Open this publication in new window or tab >>Water Circulation and Marine Environment in the Antarctic Traced by Speciation of I-129 and I-127
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2017 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, 7726Article in journal (Refereed) Published
Abstract [en]

Emissions of anthropogenic I-129 from human nuclear activities are now detected in the surface water of the Antarctic seas. Surface seawater samples from the Drake Passage, Bellingshausen, Amundsen, and Ross Seas were analyzed for total I-129 and I-127, as well as for iodide and iodate of these two isotopes. The variability of I-127 and I-129 concentrations and their species (I-127(-)/(IO3-)-I-127, I-129(-)/(IO3-)-I-129) suggest limited environmental impact where ((1.15-3.15) x 10(6) atoms/L for I-129 concentration and (0.61-1.98) x 10(-11) for I-129/I-127 atomic ratios are the lowest ones compared to the other oceans. The iodine distribution patterns provide useful information on surface water transport and mixing that are vital for better understanding of the Southern Oceans effects on the global climate change. The results indicate multiple spatial interactions between the Antarctic Circumpolar Current (ACC) and Antarctic Peninsula Coastal Current (APCC). These interactions happen in restricted circulation pathways that may partly relate to glacial melting and icebergs transport. Biological activity during the warm season should be one of the key factors controlling the reduction of iodate in the coastal water in the Antarctic.

Place, publisher, year, edition, pages
Nature Publishing Group, 2017
National Category
Oceanography, Hydrology and Water Resources
Identifiers
urn:nbn:se:uu:diva-334040 (URN)10.1038/s41598-017-07765-w (DOI)000407400100013 ()28798296 (PubMedID)
Available from: 2017-11-22 Created: 2017-11-22 Last updated: 2018-01-13Bibliographically approved
Ström, P., Petersson, P., Rubel, M. & Possnert, G. (2016). A combined segmented anode gas ionization chamber and time-of-flight detector for heavy ion elastic recoil detection analysis. Paper presented at AIVELA 11th International Conference on Vibration Measurements by Laser and Noncontact Techniques, Univ Politecnica Marche, Italian Assoc LAser VElocimetry & Noninvas Diagno, Ancona, ITALY JUN 25-27, 2014. Review of Scientific Instruments, 87(10), Article ID 103303.
Open this publication in new window or tab >>A combined segmented anode gas ionization chamber and time-of-flight detector for heavy ion elastic recoil detection analysis
2016 (English)In: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 87, no 10, 103303Article in journal (Refereed) Published
Abstract [en]

A dedicated detector system for heavy ion elastic recoil detection analysis at the Tandem Laboratory of Uppsala University is presented. Benefits of combining a time-of-flight measurement with a segmented anode gas ionization chamber are demonstrated. The capability of ion species identification is improved with the present system, compared to that obtained when using a single solid state silicon detector for the full ion energy signal. The system enables separation of light elements, up to Neon, based on atomic number while signals from heavy elements such as molybdenum and tungsten are separated based on mass, to a sample depth on the order of 1 mu m. The performance of the system is discussed and a selection of material analysis applications is given. Plasma-facing materials from fusion experiments, in particular metal mirrors, are used as a main example for the discussion. Marker experiments using nitrogen-15 or oxygen-18 are specific cases for which the described improved species separation and sensitivity are required. Resilience to radiation damage and significantly improved energy resolution for heavy elements at low energies are additional benefits of the gas ionization chamber over a solid state detector based system.

National Category
Accelerator Physics and Instrumentation
Identifiers
urn:nbn:se:uu:diva-310678 (URN)10.1063/1.4963709 (DOI)000387661900024 ()27802744 (PubMedID)
Conference
AIVELA 11th International Conference on Vibration Measurements by Laser and Noncontact Techniques, Univ Politecnica Marche, Italian Assoc LAser VElocimetry & Noninvas Diagno, Ancona, ITALY JUN 25-27, 2014
Available from: 2017-01-09 Created: 2016-12-19 Last updated: 2017-11-29Bibliographically approved
Inceoglu, F., Knudsen, M. F., Olsen, J., Karoff, C., Herren, P.-A. -., Schwikowski, M., . . . Possnert, G. (2016). A continuous ice-core Be-10 record from Mongolian mid-latitudes: Influences of solar variability and local climate. Earth and Planetary Science Letters, 437, 47-56.
Open this publication in new window or tab >>A continuous ice-core Be-10 record from Mongolian mid-latitudes: Influences of solar variability and local climate
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2016 (English)In: Earth and Planetary Science Letters, ISSN 0012-821X, E-ISSN 1385-013X, Vol. 437, 47-56 p.Article in journal (Refereed) Published
Abstract [en]

High-resolution Be-10 records used for studies of detailed changes in atmospheric Be-10 production rates predominantly derive from polar ice cores. In this study, we present the first Be-10 record from a mid latitude ice core. The ice core derives from the Tsambagarav mountain range located in the Mongolian Altai region. The new Be-10 concentration record spans the period from AD 1550 to 2009, while the flux record extends from AD 1816 to 2009. The Be-10 concentration in the Tsambagarav ice core ranges between similar to 1.5 x 10(4) and similar to 10 x 10(4) atoms g(-1), whereas the Be-10 flux changes from similar to 0.02 to similar to 0.15 atoms cm(-2) s(-1) The average Be-10 flux at Tsambagarav is four times higher than the average Be-10 flux recorded in the NGRIP and Dome Fuji ice cores, which is in accordance with model predictions. In general, the long-term trends observed in the Tsambagarav Be-10 concentration and flux records are reasonably similar to those observed in the NGRIP ice core. A comparison between the Tsambagarav Be-10 record, group sunspot numbers (GSNs), and solar modulation potentials based on C-14 in tree rings suggests that the Maunder Minimum was associated with a prolonged maximum in Be-10 concentrations at Tsambagarav, whereas the Dalton Minimum was associated with a minor increase in the Be-10 concentration and flux that was delayed relative to the primary minimum in GSNs. The sulphate record from Tsambagarav shows that large positive anomalies in the sulphate concentration are associated with negative anomalies in the Be-10 concentration. A concurrent positive sulphate anomaly may explain why the main phase of the Dalton Minimum is subdued in the Be-10 record from Tsambagaray. Spectral analysis indicates that the 11-yr solar-cycle signal may have influenced the new Be-10 record, but the evidence supporting a direct link is ambiguous. Local and regional climatic changes, such as cyclonic versus anticyclonic conditions and related storm tracks, most likely played a significant role for the Be-10 deposition in the Tsambagarav region.

Keyword
cosmogenic nuclide, beryllium 10, mid-latitude, past solar activity, climate
National Category
Climate Research
Identifiers
urn:nbn:se:uu:diva-280227 (URN)10.1016/j.epsl.2016.01.006 (DOI)000370091100006 ()
Funder
Danish National Research Foundation, DNRF106
Note

Correction in: Earth Planet. Sci. Lett. 437 (2016) 47–56. DOI: 10.1016/j.epsl.2016.03.001

Available from: 2016-03-10 Created: 2016-03-09 Last updated: 2017-11-30Bibliographically approved
Czymzik, M., Adolphi, F., Muscheler, R., Mekhaldi, F., Martin-Puertas, C., Aldahan, A., . . . Brauer, A. (2016). A varved lake sediment record of the Be-10 solar activity proxy for the Lateglacial-Holocene transition. Quaternary Science Reviews, 153, 31-39.
Open this publication in new window or tab >>A varved lake sediment record of the Be-10 solar activity proxy for the Lateglacial-Holocene transition
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2016 (English)In: Quaternary Science Reviews, ISSN 0277-3791, E-ISSN 1873-457X, Vol. 153, 31-39 p.Article in journal (Refereed) Published
Abstract [en]

Solar modulated variations in cosmogenic radionuclide production provide both information on past changes in the activity of the Sun and a global synchronization tool. However, to date the use of cosmogenic radionuclides for these applications is almost exclusively based on Be-10 records from ice cores and C-14 time-series from tree rings, all including archive-specific limitations. We present the first Be-10 record from annually laminated (varved) lake sediments for the Lateglacial-Holocene transition from Meerfelder Maar. We quantify environmental influences on the catchment and, consequently, Be-10 deposition using a new approach based on regression analyses between our Be-10 record and environmental proxy time-series from the same archive. Our analyses suggest that environmental influences contribute to up to 37% of the variability in our Be-10 record, but cannot be the main explanation for major Be-10 excursions. Corrected for these environmental influences, our Be-10 record is interpreted to dominantly reflect changes in solar modulated cosmogenic radionuclide production. The preservation of a solar production signal in Be-10 from varved lake sediments highlights the largely unexplored potential of these archives for solar activity reconstruction, as global synchronization tool and, thus, for more robust paleoclimate studies.

Keyword
Be-10, Varved lake sediments, Solar activity, Time-scales
National Category
Geophysics
Identifiers
urn:nbn:se:uu:diva-311500 (URN)10.1016/j.quascirev.2016.10.007 (DOI)000389116000003 ()
Funder
German Research Foundation (DFG), CZ 227/1-1Swedish Research Council, 2013-8421
Available from: 2016-12-28 Created: 2016-12-28 Last updated: 2017-11-29Bibliographically approved
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