| 1. |
- Cassetta, L, et al.
(författare)
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Differential expansion of circulating human MDSC subsets in patients with cancer, infection and inflammation
- 2020
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Ingår i: Journal for immunotherapy of cancer. - : BMJ. - 2051-1426. ; 8:2
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Tidskriftsartikel (refereegranskat)abstract
- Myeloid-derived suppressor cells (MDSC) are a functional myeloid cell subset that includes myeloid cells with immune suppressive properties. The presence of MDSC has been reported in the peripheral blood of patients with several malignant and non-malignant diseases. So far, direct comparison of MDSC across different diseases and Centers is hindered by technical pitfalls and a lack of standardized methodology. To overcome this issue, we formed a network through the COST Action Mye-EUNITER (www.mye-euniter.eu) with the goal to standardize and facilitate the comparative analysis of human circulating MDSC in cancer, inflammation and infection. In this manuscript, we present the results of the multicenter study Mye-EUNITER MDSC Monitoring Initiative, that involved 13 laboratories and compared circulating MDSC subsets across multiple diseases, using a common protocol for the isolation, identification and characterization of these cells.MethodsWe developed, tested, executed and optimized a standard operating procedure for the isolation and immunophenotyping of MDSC using blood from healthy donors. We applied this procedure to the blood of almost 400 patients and controls with different solid tumors and non-malignant diseases. The latter included viral infections such as HIV and hepatitis B virus, but also psoriasis and cardiovascular disorders.ResultsWe observed that the frequency of MDSC in healthy donors varied substantially between centers and was influenced by technical aspects such as the anticoagulant and separation method used. Expansion of polymorphonuclear (PMN)-MDSC exceeded the expansion of monocytic MDSC (M-MDSC) in five out of six solid tumors. PMN-MDSC expansion was more pronounced in cancer compared with infection and inflammation. Programmed death-ligand 1 was primarily expressed in M-MDSC and e-MDSC and was not upregulated as a consequence of disease. LOX-1 expression was confined to PMN-MDSC.ConclusionsThis study provides improved technical protocols and workflows for the multi-center analysis of circulating human MDSC subsets. Application of these workflows revealed a predominant expansion of PMN-MDSC in solid tumors that exceeds expansion in chronic infection and inflammation.
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| 2. |
- Lederman, J. S., et al.
(författare)
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International collaborative follow-up investigation of graduating high school students' understandings of the nature of scientific inquiry : is progress Being made?
- 2021
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Ingår i: International Journal of Science Education. - : Informa UK Limited. - 0950-0693 .- 1464-5289. ; 43:7, s. 991-1016
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Tidskriftsartikel (refereegranskat)abstract
- Understandings of the nature of scientific inquiry (NOSI), as opposed to engaging students in inquiry learning experiences, are included in science education reform documents around the world. However, little is known about what students have learned about NOSI during their pre-college school years. The purpose of this large-scale follow-up international project (i.e. 32 countries and regions, spanning six continents and including 3917 students for the high school sample) was to collect data on what exiting high school students have learned about NOSI. Additionally, the study investigated changes in 12th grade students' NOSI understandings compared to seventh grade (i.e. 20 countries and regions) students' understandings from a prior investigation [Lederman et al. (2019). An international collaborative investigation of beginning seventh grade students' understandings of scientific inquiry: Establishing a baseline. Journal of Research in Science Teaching, 56(4), 486-515. ]. This study documents and discusses graduating high school students' understandings and compares their understandings to seventh grade students' understandings of the same aspects of scientific inquiry for each country. It is important to note that collecting data from each of the 130+ countries globally was not feasible. Similarly, it was not possible to collect data from every region of each country. A concerted effort was made, however, to provide a relatively representative picture of each country and the world.
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| 3. |
- Håkansson, H., et al.
(författare)
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In vivo and in vitro toxicity of fractionated fish lipids, with particular regard to their content of chlorinated organic compounds
- 1991
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Ingår i: Pharmacology and Toxicology. - : Wiley. - 0901-9928 .- 1600-0773. ; 69:6, s. 459-471
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Tidskriftsartikel (refereegranskat)abstract
- Six different lipid matrices (the intact lipid (IL), four lipid fractions with different polarity, and the free fatty acids (FFAs) obtained by hydrolysis of the triacylglycerol (TAG) containing fraction) were obtained from salmon (Salmo salar) and eel (Anguilla anguilla), each collected at a contaminated and a comparatively uncontaminated catch site along the coast of Scandinavia. The lipid matrices were studied in toxicological test systems representing various biological functions of different organ systems from several species and trophic levels. The results were evaluated with particular respect to the concentrations of extractable organically bound chlorine (EOCl) in the matrices tested. In some test systems, the specimens with a higher EOCl concentration appeared to be more toxic. For example, the TAG containing fraction (F2) from Idefjord eel, having a higher EOCl content than F2 from Oslofjord eel, reduced the number and hatchability of eggs laid by zebrafish. Both IL and F2 of Idefjord eel increased mortality and reduced the oxygen/nitrogen-ratio in blue mussels. Non-polar compounds (F1) from Bothnian Sea salmon induced 7-ethoxyresurofin O-deethylase (EROD) activity in rainbow trout hepatocytes, whereas F1 from Senja salmon did not. F1 from Bothnian Sea salmon also reduced the number of T-cells in foetal mouse thymus anlagen in vitro compared with the cell number in anlagen exposed to F1 from Senja salmon. A positive correlation between EOCl concentration and test response was found for EROD activity in rainbow trout hepatocytes and for ATP-leakage in Erlich ascites tumour cells when testing the phospolipid containing fraction (F4). However, in most test systems the fish oils, irrespective of EOCl content, were of low toxicity, and the observed effects need to be verified in future studies.
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| 4. |
- Visser, E.K., et al.
(författare)
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Does Horse Temperament Influence Horse-Rider Cooperation?
- 2008
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Ingår i: Journal of Applied Animal Welfare Science. - : Informa UK Limited. - 1088-8705 .- 1532-7604. ; 11:3, s. 267-284
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Tidskriftsartikel (refereegranskat)abstract
- Cooperation between rider and horse is of major importance in equitation. A balanced team of horse and rider improves (sport) performances and welfare aspects by decreasing stress, frustration, risks of injuries, and accidents. Important features affecting the cooperation are the physical skills, knowledge, and personality of the rider on one hand and the temperament, experience, and physical abilities of the horse on the other. A study with 16 riders and 16 warm-blood riding horses tested the effect of personality of riders and temperament of horses on cooperation between riders and horses. More emotionally reactive horses showed more evasive behavior during riding. Riders preferred to ride those horses who were assessed by the riders as being attentive to the rider's aid. The frequency of evasive behaviors during riding - as assessed by riders, in contrast to the assessments made by an external judge - influenced the cooperation between rider and horse. On average, a rider's personality did not affect the cooperation between rider and horse; however, it is suggested that a rider's personality does affect the cooperation with more emotionally reactive horses.
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| 5. |
- Gaillard, Marie-José, 1953-, et al.
(författare)
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Holocene land-cover reconstructions for studies on land cover-climate feedbacks
- 2010
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Ingår i: Climate of the Past. - : Copernicus GmbH. - 1814-9324 .- 1814-9332. ; 6, s. 483-499
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Tidskriftsartikel (refereegranskat)abstract
- The major objectives of this paper are: (1) to review the pros and cons of the scenarios of past anthropogenic land cover change (ALCC) developed during the last ten years, (2) to discuss issues related to pollen-based reconstruction of the past land-cover and introduce a new method, REVEALS (Regional Estimates of VEgetation Abundance from Large Sites), to infer long-term records of past land-cover from pollen data, (3) to present a new project (LANDCLIM: LAND cover – CLIMate interactions in NW Europe during the Holocene) currently underway, and show preliminary results of REVEALS reconstructions of the regional land-cover in the Czech Republic for five selected time windows of the Holocene, and (4) to discuss the implications and future directions in climate and vegetation/land-cover modeling, and in the assessment of the effects of human-induced changes in land-cover on the regional climate through altered feedbacks. The existing ALCC scenarios show large discrepancies between them, and few cover time periods older than AD 800. When these scenarios are used to assess the impact of human land-use on climate, contrasting results are obtained. It emphasizes the need for methods such as the REVEALS model-based land-cover reconstructions. They might help to fine-tune descriptions of past land-cover and lead to a better understanding of how long-term changes in ALCC might have influenced climate. The REVEALS model is demonstrated to provide better estimates of the regional vegetation/landcover changes than the traditional use of pollen percentages. This will achieve a robust assessment of land cover at regional- to continental-spatial scale throughout the Holocene. We present maps of REVEALS estimates for the percentage cover of 10 plant functional types (PFTs) at 200 BP and 6000 BP, and of the two open-land PFTs “grassland” and “agricultural land” at five time-windows from 6000 BP to recent time. The LANDCLIM results are expected to provide crucial data to reassess ALCC estimates for a better understanding of the land suface-atmosphere interactions.
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| 6. |
- Sirtl, T., et al.
(författare)
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Adsorption structure determination of a large polyaromatic trithiolate on Cu(111) : Combination of LEED-I(V) and DFT-vdW
- 2013
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Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 15:26, s. 11054-11060
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Tidskriftsartikel (refereegranskat)abstract
- The adsorption geometry of 1,3,5-tris(4-mercaptophenyl)benzene (TMB) on Cu(111) is determined with high precision using two independent methods, experimentally by quantitative low energy electron diffraction (LEED-I(V)) and theoretically by dispersion corrected density functional theory (DFT-vdW). Structural refinement using both methods consistently results in similar adsorption sites and geometries. Thereby a level of confidence is reached that allows deduction of subtle structural details such as molecular deformations or relaxations of copper substrate atoms.
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| 7. |
- Gauthier, Y., et al.
(författare)
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Reconstruction of the Pt50Ni50(100) surface : a LEED and STM study
- 1995
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Ingår i: Surface Science. - 0039-6028. ; 327:1-2, s. 100-120
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Tidskriftsartikel (refereegranskat)abstract
- The structure of the Pt50Ni50(100) surface was investigated by low energy electron diffraction (LEED) and scanning tunnelling spectroscopy (STM). Superstructures corresponding to 12 × 1 and 19 × 1 reconstructions were observed in the LEED pattern, and these reconstructions were identified with atomic resolution by STM. The reconstructed surface layer has a quasi-hexagonal atomic mesh with almost (111) atomic density and is divided into terraces and domains the size of which can be more than a thousand ångströms. The domains are corrugated with protrusions made up by 5 × 1 subunits of the quasi-hexagonal mesh and with valleys containing depressed atoms or 2 × 1 subunits. The 12 × 1 and 19 × 1 periodicities are determined by the sequence of valleys; depending on the thermal treatment, one or the other dominates but both generally coexist on the terrace. Owing to the complexity of the structure, LEED calculations were performed for a simplified model with surface atoms situated in a planar net and uniform quasi-hexagonal meshes. We find that in both reconstructions the two surface layers are significantly enriched with platinum. The top layer enrichment is consistent with previous Auger measurements. © 1995.
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| 8. |
- Jones, T. R., et al.
(författare)
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Delayed maximum northern European summer temperatures during the Last Interglacial as a result of Greenland Ice Sheet melt
- 2017
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Ingår i: Geology. - 0091-7613. ; 45:1, s. 23-26
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Tidskriftsartikel (refereegranskat)abstract
- Here we report a new quantitative mean July temperature reconstruction using non-biting midges (chironomids) from the Danish Last Interglacial (LIG) site Hollerup (spanning 127-116 ka). We find that peak mean July temperatures of 17.5 °C, similar to those of the present day (1961-1990 CE), were reached shortly before the onset of the regional Carpinus pollen zone. Through comparison to terrestrial and marine sequences we demonstrate that peak summer warmth took place some three millennia after the onset of LIG warming in Europe, a marked delay in line with records from the North Atlantic. Crucially, the warmest northern European summer temperatures appear to follow maximum Greenland Ice Sheet mass loss, implying that meltwater substantially reduced Atlantic Meridional Overturning Circulation and depressed European temperatures during the early part of the interglacial.
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| 9. |
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| 10. |
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| 11. |
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| 12. |
- A. Manneh, Ilana, et al.
(författare)
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Progression in action for developing chemical knowledge
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- In this paper, we discuss the well-known teaching challenge of how to provide undergraduate students with basic chemistry knowledge without making them experience these basics as meaningless and unintelligible. First, we situate the challenge in a classic dilemma: should we teach the necessary basic facts before the chemical explanations or should the explanations be taught before or in parallel to these facts? Here we draw on examples from interviews with graduate students reflecting on their experiences regarding their studies at the undergraduate level. Second, we suggest a way out of the dilemma, through a shift in perspective from the typical progression of facts and explanations towards a purpose and activity-based progression. We conclude with a discussion of implications of such a shift for university chemistry education together with suggestions for future research.
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| 13. |
- A. Manneh, Ilana, 1970-, et al.
(författare)
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Tutor-student interaction in undergraduate chemistry : a case of learning to make relevant distinctions of molecular structures for determining oxidation states of atoms
- 2018
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Ingår i: International Journal of Science Education. - : Informa UK Limited. - 0950-0693 .- 1464-5289. ; 40:16, s. 2023-2043
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we explore the issues and challenges involved in supporting students’ learning to discern relevant and critical aspects of determining oxidation states of atoms in complex molecules. We present a detailed case of an interaction between three students and a tutor during a problem-solving class, using the analytical tool of practical epistemology analysis (PEA). The results show that the ability to make relevant distinctions between the different parts of a molecule for solving the problem, even with the guidance of the tutor, seemed to be challenging for students. These shifts were connected to both purposes that were specific for solving the problem at hand, and additional purposes for general learning of the subject matter, in this case how to assign oxidation states in molecules. The students sometimes could not follow the additional purposes introduced by the tutor, which made the related distinctions more confusing. Our results indicate that in order to provide adequate support and guidance for students the tutor needs to consider how to sequence, move between, and productively connect the different purposes introduced in a tutor-student interaction. One way of doing that is by first pursuing the purposes for solving the problem and then successively introduce additional, more general purposes for developing students’ learning of the subject matter studied. Further recommendations drawn from this study are discussed as well.
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| 14. |
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| 15. |
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| 16. |
- ANDERSSON, B, et al.
(författare)
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Angiotensin and the brain
- 1995
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Ingår i: Acta physiologica Scandinavica. - : Wiley. - 0001-6772 .- 1365-201X. ; 155:2, s. 117-125
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Tidskriftsartikel (refereegranskat)
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| 17. |
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| 18. |
- Beerling, D. J., et al.
(författare)
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Leaf metabolic and morphological responses of dwarf willow (Salix herbacea) in the sub-arctic to the past 9000 years of global environmental change
- 2000
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Ingår i: New Phytologist. - : Wiley. - 0028-646X .- 1469-8137. ; 145:2, s. 257-269
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Tidskriftsartikel (refereegranskat)abstract
- Ice-core records of the concentration of atmospheric CO2 and its stable isotope ratio (δ13C(a)) have shown that the global C cycle has not remained in steady-state over the past 11000 yr, implying a possible change in vegetation activity over this period. Here we evaluated the ecophysiological responses of the dwarf willow (Salix herbacea) over the past 9000 yr by measuring the stable carbon isotope composition and stomatal characters of a unique, well dated, high-latitude (68°N) sub-fossil leaf sequence. After correction for corresponding changes in δ13C(a), 9000-yr record of variations in the ratio of intercellular (c(j)) to atmospheric (c(a)) CO2 concentration was established. Intercellular: atmospheric CO2 concentration ratios provide a time-integrated indicator of the set-point of leaf gas exchange, and the historical variations revealed in this record have been interpreted as an impact of environmental changes on leaf gas exchange. The sequence shows a progressive fall in c(i)/c(a) 9000-3000 yr BP as well as the climatic effects of the Medieval Warm Period, the Little Ice Age and the post-industrial CO2 rise. Leaf stomatal index (proportion of epidermal cells as stomata), but not stomatal density, was significantly (P <0.01) correlated with Holocene atmospheric CO2 variations. A process-based interpretation of the changes in c(i)/c(a) was made using two different coupled photosynthesis-stomatal conductance models. Calculated in this way, S. herbacea photosynthetic rates were relatively stable throughout the Holocene whilst stomatal conductance progressively declined. Both, however, showed the marked effects of the Medieval Warm Period and the Little Ice Age. Overall, the results demonstrate that S. herbacea leaf metabolism, like the global C cycle, has not remained in steady state during the Holocene but has responded to changes in atmospheric CO2 concentration and short-term climatic oscillations.
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| 19. |
- Björck, S., et al.
(författare)
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The Preboreal oscillation around the Nordic Seas : Terrestrial and lacustrine responses
- 1997
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Ingår i: Journal of Quaternary Science. - 0267-8179. ; 12:6, s. 455-465
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Tidskriftsartikel (refereegranskat)abstract
- The occurrence of an early Preboreal climatic cooling/oscillation (PBO) in lacustrine and glacial records from northwest Europe, Iceland and Greenland is reviewed and documented. The often subtle response of the proxy records to this oscillation, in combination with its short duration, make it difficult to detect. Owing to its chronostratigraphic position between the 10000-9900 and 9600-9500 14C plateaux (c. 11 300-11 150 calendar yr BP) it is also difficult to 14C date with precision. We find that the vegetation response to the PBO varies between sites and regions. In contrast to the pioneer vegetation in Iceland and southern Sweden, the expanding birch-pine forest in Germany-Denmark was more susceptible to deteriorating growing conditions. The combined lacustrine, tree-ring and glacial records imply that the PBO was characterised by cool and humid conditions throughout northwestern and central Europe. This is documented by vegetation changes, decreased aquatic production, increased soil erosion, increased 2H and 13C content in tree-rings, readvances or stillstands of the ice sheet in Norway and Finland, and ingression of brackish water into the Baltic. Icelandic proxy records from lake sediments and glacial moraines imply cooler conditions than during the previous Preboreal period, but not as extreme as during the Younger Dryas. Greenland records suggest that the early Preboreal was characterised by ice readvances, as an effect of cool climate and increased precipitation (in relation to the Younger Dryas). It was not until the end of the PBO that climate was warm enough to melt the land-based ice sheet. This Preboreal oscillation, found on both sides of the Nordic Seas, is interpreted as an effect of increased freshwater forcing on the thermohaline circulation in the Nordic Seas, which is implied by a simultaneous and distinct rise in the atmospheric 14C/12C ratio. A slow-down of the thermohaline circulation may temporarily have pushed the Polar Front further south.
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| 20. |
- Eriksson, S, et al.
(författare)
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Hypertension and thirst outlasting renal vasoconstriction as effects of a brief evaluation of systemic angiotensin II in sheep.
- 1994
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Ingår i: Acta Physiologica Scandinavica. - : Wiley. - 0001-6772 .- 1365-201X. ; 150:2, s. 181-8
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Tidskriftsartikel (refereegranskat)abstract
- The influence of 10 min intracarotid (i.c.) and intravenous (i.v.) infusions of angiotensin II (Ang II; 20 pmol kg-1 min-1) on carotid blood pressure (cBP) and renal blood flow (RBF) was studied in unanaesthetized ewes without and with pre-treatment with the alpha 1- and beta-adrenoceptor blocker labetalol. RBF was also monitored during 30 min intracerebroventricular (ICV) infusions of Ang II at 2 pmol kg-1 min-1. The i.c. infusions of Ang II induced about 50 mmHg rise in cBP. A steep decline occurred during 5 min post-infusion, followed by a much slower reduction with the cBP remaining above control level at 40 min post-infusion. The pressure elevation induced by i.v. Ang II was less pronounced but exhibited a similar pattern. Labetalol significantly reduced the pressor response to i.c. as well as i.v. Ang II. The i.c. and i.v. infusions of Ang II conspicuously reduced the RBF regardless of whether the ewes were labetalol-treated or not. At 5 min after the infusions RBF had returned to control level. The ICV infusions did not influence the RBF. Ang II i.c. elicited thirst in 50% of the ewes with the urge to drink remaining at 40 min post-infusion. The dipsogenic response was not reduced by labetalol pretreatment. The results imply that no cerebral component contributes to the reduction in RBF induced by systemic Ang II. However, a centrally mediated action seems to be the cause of the long-lasting post-infusion cBP elevation and dipsogenic response.(ABSTRACT TRUNCATED AT 250 WORDS)
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| 21. |
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| 22. |
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| 23. |
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| 24. |
- Frithiof, R, et al.
(författare)
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Activation of central opioid receptors determines the timing of hypotension during acute hemorrhage-induced hypovolemia in conscious sheep
- 2006
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Ingår i: American journal of physiology. Regulatory, integrative and comparative physiology. - : American Physiological Society. - 0363-6119 .- 1522-1490. ; 291:4, s. R987-R996
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Tidskriftsartikel (refereegranskat)abstract
- After an initial compensatory phase, hemorrhage reduces blood pressure due to a widespread reduction of sympathetic nerve activity (decompensatory phase). Here, we investigate the influence of intracerebroventricular naloxone (opioid-receptor antagonist) and morphine (opioid-receptor agonist) on the two phases of hemorrhage, central and peripheral hemodynamics, and release of vasopressin and renin in chronically instrumented conscious sheep. Adult ewes were bled (0.7 ml·kg−1·min−1) from a jugular vein until mean arterial blood pressure (MAP) reached 50 mmHg. Starting 30 min before and continuing until 60 min after hemorrhage, either artificial cerebrospinal fluid (aCSF), naloxone, or morphine was infused intracerebroventricularly. Naloxone (200 μg/min but not 20 or 2.0 μg/min) significantly increased the hemorrhage volume compared with aCSF (19.5 ± 3.2 vs. 13.9 ± 1.1 ml/kg). Naloxone also increased heart rate and cardiac index. Morphine (2.0 μg/min) increased femoral blood flow and decreased hemorrhage volume needed to reduce MAP to 50 mmHg (8.9 ± 1.5 vs. 13.9 ± 1.1 ml/kg). The effects of morphine were abolished by naloxone at 20 μg/min. It is concluded that the commencement of the decompensatory phase of hemorrhage in conscious sheep involves endogenous activation of central opioid receptors. The effective dose of morphine most likely activated μ-opioid receptors, but they appear not to have been responsible for initiating decompensation as 1) naloxone only inhibited an endogenous mechanism at a dose much higher than the effective dose of morphine, and 2) the effects of morphine were blocked by a dose of naloxone, which, by itself, did not delay the decompensatory phase.
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| 25. |
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| 26. |
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| 27. |
- Frithiof, R, et al.
(författare)
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Hypothalamic paraventricular nucleus mediates sodium-induced changes in cardiovascular and renal function in conscious sheep
- 2009
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Ingår i: American journal of physiology. Regulatory, integrative and comparative physiology. - : American Physiological Society. - 1522-1490 .- 0363-6119. ; 297:1, s. R185-R193
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Tidskriftsartikel (refereegranskat)abstract
- The contribution of the paraventricular nucleus of the hypothalamus (PVN) in mediating cardiovascular, renal, hormonal, and sympathetic nerve responses to increased cerebrospinal fluid (CSF) [Na+] was investigated in conscious sheep. Intracerebroventricular hypertonic NaCl (0.5 mol/l, 20 μl/min for 60 min) increased arterial blood pressure [AP; +13.4 (sd 2.0) mmHg, P < 0.001] and central venous pressure [CVP; +2.8 (sd 1.3) mmHg, P < 0.001], but did not significantly change heart rate or cardiac output ( n = 6). Elevated CSF [Na+] also lowered plasma ANG II levels [−3.3 (sd 1.6) pmol/l, P = 0.004] and increased creatinine clearance [+31.5 (sd 32.7) ml/min, P = 0.03] and renal sodium excretion [+9.2 (sd 9.2) mmol/h, P = 0.003]. Lidocaine injection (1 μl, 2%) into the PVN prior to the ICV infusion had no apparent effect per se, but it abolished the AP, CVP, creatinine clearance, and ANG II responses to hypertonic NaCl, as well as reducing the increase in renal sodium excretion ( n = 6). Subsequent studies were performed in conscious sheep with chronically implanted electrodes for measurement of renal sympathetic nerve activity (RSNA). The effects of ICV hypertonic NaCl on AP and RSNA were measured before and after PVN-injection of glycine (250 nmol in 500 nl artificial CSF). ICV NaCl increased AP and decreased RSNA ( P < 0.001). These effects were significantly reduced by glycine ( P = 0.02–0.001, n = 5). Saline injected into the PVN ( n = 5) or lidocaine injected outside the PVN ( n = 6) had no effect on the response to ICV hypertonic NaCl. These results indicate that the PVN is an important mediator of cerebrally induced homeostatic responses to elevated sodium concentration/hyperosmolality.
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| 28. |
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| 29. |
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| 30. |
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| 31. |
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| 32. |
- Gunnarsson, Ulf, 1967-, et al.
(författare)
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Centrally mediated influences of hypertonic NaCl and angiotensin II on regional blood flow and hemodynamic responses to hypotensive hemorrhage in conscious sheep.
- 1994
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Ingår i: Shock. - 1073-2322 .- 1540-0514. ; 2:1, s. 60-7
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Tidskriftsartikel (refereegranskat)abstract
- The influence of separate and combined intracerebroventricular (ICV) infusions of hypertonic (.5 M) NaCl (HTNa) at .02 mL min-1 and angiotensin II (ANG II) at 1 pmol kg-1 min-1 on tolerance to hemorrhage, accompanying systemic hemodynamic changes, and regional blood flow was studied in adult conscious sheep. Corresponding measurements during ICV .9% NaCl served as controls. The hemorrhage volume needed to lower the blood pressure to about 50 mmHg was significantly larger during treatment with HTNa and HTNa/ANG II (27.8 +/- 2.2 and 28.3 +/- 2.5 mL kg-1, respectively; p < .001; about 45% of estimated blood volume) as well as during ANG II (20.1 +/- 1.3 mL kg-1; p < .01) compared to controls (15.1 +/- .7 mL kg-1; about 25% of estimated blood volume). In spite of a larger hemorrhage volume, the lowering of the cardiac output was not accentuated, and its subsequent recovery was not impaired during ICV infusion of HTNa or HTNa/ANG II. Similarly, the posthemorrhage restoration of the systemic blood pressure was not negatively affected by the more pronounced hypovolemia induced during the ICV treatments compared to controls. In contrast to ANG II, HTNa infusion, alone or in combination with ANG II, was accompanied by a significantly lower renal blood flow, and a higher renovascular resistance, during the posthemorrhage period. The femoral blood flow was maintained or even slightly elevated after hemorrhage in all experiments. The integrated results of the study imply differentiated hemodynamic effects of centrally administered HTNa and ANG II.(ABSTRACT TRUNCATED AT 250 WORDS)
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| 33. |
- Gunnarsson, Ulf, 1967-, et al.
(författare)
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Inefficiency of intracerebroventricular ANP to alter haemodynamic, plasma vasopressin and renin responses to haemorrhage in sheep.
- 1994
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Ingår i: Acta Physiologica Scandinavica. - : Wiley. - 0001-6772 .- 1365-201X. ; 150:4, s. 441-7
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Tidskriftsartikel (refereegranskat)abstract
- Whether intracerebroventricular (i.c.v.) infusion of atrial natriuretic peptide (human-ANP, 1-28) 25 pmol min-1 influences the tolerance to blood loss and haemorrhage induced cardiovascular, vasopressin and renin responses were studied in five conscious sheep. The i.c.v. infusion was started 60 min prior to a slow (0.7 ml kg-1 min-1) venous haemorrhage, was run concurrently with bleeding, and for 90 min thereafter. Venous blood was removed until the mean systemic arterial pressure suddenly fell to about 50 mmHg. There were no statistically significant differences in either the bleeding volume necessary to induce the sudden decrease in blood pressure, or in cardiovascular parameters measured by venous heart thermodilution catheterization, compared with control experiments with i.c.v. infusion of artificial CSF. The plasma protein and vasopressin concentrations and renin activity were unaffected by the i.c.v. infusion of ANP as were the changes in these parameters occurring during the subsequent haemorrhage. The same negative findings were obtained with a three times higher dose of ANP(1-28) (75 pmol min-1), tested in three of the animals. Thus the i.c.v. infusion of ANP(1-28), in amounts expected to elevate the CSF concentration far above basal levels does apparently not influence normal blood pressure regulation or alter haemodynamic, vasopressin and renin responses to haemorrhage in conscious sheep.
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| 34. |
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| 35. |
- Hammar, M., et al.
(författare)
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Surface atomic structure of reconstructed VC0.8(111) studied with scanning tunneling microscopy
- 1992
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Ingår i: Physical Review B. - 0163-1829. ; 45:11, s. 6118-6123
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Tidskriftsartikel (refereegranskat)abstract
- Scanning tunneling microscopy has been performed on the reconstructed polar surface of substoichiometric VC0.80(111). A mixture of (8×1) and (3 × 3) R30°reconstructed areas was found. The (8×1) periodicity could be determined to be the result of a square-lattice surface layer superimposed on the hexagonal substrate. As this square lattice must have its origin in strong and directed in-plane bonds with the relatively large length of about 2.9, it can be deduced to consist of vanadium atoms. Lateral positions of these vanadium surface atoms with respect to the substrate are suggested from the measured surface corrugation. The (3 × 3) R30°structure was found in small triangular areas which can, due to the measured step heights between the two reconstructions, be believed to be carbon terminated. The occurrence of a reconstructed surface with a reduced atomic concentration is in contrast to what is known for TiC(111) and NbC(111), both having stable (1×1) surfaces. A qualitative explanation for this difference is suggested. © 1992 The American Physical Society.
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| 36. |
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| 37. |
- Hjelmqvist, H, et al.
(författare)
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Increased resistance to haemorrhage induced by intracerebroventricular infusion of hypertonic NaCl in conscious sheep.
- 1992
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Ingår i: Acta Physiologica Scandinavica. - : Wiley. - 0001-6772 .- 1365-201X. ; 145:2, s. 177-86
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Tidskriftsartikel (refereegranskat)abstract
- The effect of elevated cerebrospinal fluid Na+ concentration (CSF [Na+]) on the tolerance of blood loss, and concomitant cardiovascular and humoral responses were studied in conscious sheep. A slow (0.7 ml kg-1 min-1) venous haemorrhage was continued until the mean systemic arterial pressure suddenly decreased to less than 50 mmHg, or in the absence of hypotension, until a total blood loss of 25 ml kg-1. Significantly more blood had to be removed to induce hypotension in animals receiving an intracerebroventricular (i.c.v.) infusion (0.02 ml min-1) of 0.5 M NaCl (starting 30 min before haemorrhage and continued throughout the experiment) compared to control haemorrhages without concomitant i.c.v. infusion (22.7 +/- 1.2 ml vs 16.9 +/- 0.9 ml kg-1). In one animal, subjected to 0.5 M NaCl infusion, the blood pressure was still maintained at 25 ml kg-1 of haemorrhage. In spite of a larger blood loss, animals receiving i.c.v. infusion of hypertonic NaCl had an improved recovery of the blood pressure after haemorrhage, due to a better maintained cardiac output rather than to a reinforced increase of the vascular resistance. The improved cardiovascular responses to haemorrhage during elevated CSF [Na+] are not readily explained by the effects on the plasma concentrations of vasopressin, angiotensin II or noradrenaline, although the latter was augmented. The plasma protein concentration decreased already during the 30 min of hypertonic NaCl infusion preceding haemorrhage, and the haemodilution caused by the subsequent blood removal was aggravated, which indicates that this treatment also causes transfer of fluid to the plasma compartment. We conclude that elevated CSF [Na+] increases tolerance to haemorrhage and improves cardiovascular function after blood loss in sheep. Since the haemodynamic responses in many respects were similar to those reported in response to the systemic administration of a small volume of hypertonic NaCl solution in haemorrhagic shock, part of the effect of that treatment may be mediated via cerebral effects of increased Na+ concentration.
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| 38. |
- Jaenson, Thomas G. T., et al.
(författare)
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First evidence of established populations of the taiga tick Ixodes persulcatus (Acari: Ixodidae) in Sweden
- 2016
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Ingår i: Parasites & Vectors. - : Springer Science and Business Media LLC. - 1756-3305. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Background: The tick species Ixodes ricinus and I. persulcatus are of exceptional medical importance in the western and eastern parts, respectively, of the Palaearctic region. In Russia and Finland the range of I. persulcatus has recently increased. In Finland the first records of I. persulcatus are from 2004. The apparent expansion of its range in Finland prompted us to investigate if I. persulcatus also occurs in Sweden. Methods: Dog owners and hunters in the coastal areas of northern Sweden provided information about localities where ticks could be present. In May-August 2015 we used the cloth-dragging method in 36 localities potentially harbouring ticks in the Bothnian Bay area, province Norrbotten (NB) of northern Sweden. Further to the south in the provinces Vasterbotten (VB) and Uppland (UP) eight localities were similarly investigated. Results: Ixodes persulcatus was detected in 9 of 36 field localities in the Bothnian Bay area. Nymphs, adult males and adult females (n = 46 ticks) of I. persulcatus were present mainly in Alnus incana - Sorbus aucuparia - Picea abies - Pinus sylvestris vegetation communities on islands in the Bothnian Bay. Some of these I. persulcatus populations seem to be the most northerly populations so far recorded of this species. Dog owners asserted that their dogs became tick-infested on these islands for the first time 7-8 years ago. Moose (Alces alces), hares (Lepus timidus), domestic dogs (Canis lupus familiaris) and ground-feeding birds are the most likely carriers dispersing I. persulcatus in this area. All ticks (n = 124) from the more southern provinces of VB and UP were identified as I. ricinus. Conclusions: The geographical range of the taiga tick has recently expanded into northern Sweden. Increased information about prophylactic, anti-tick measures should be directed to people living in or visiting the coastal areas and islands of the Baltic Bay.
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| 39. |
- Kaufmann, Ilana, et al.
(författare)
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Developing an approach for teaching and learning about Lewis structures
- 2017
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Ingår i: International Journal of Science Education. - : Informa UK Limited. - 0950-0693 .- 1464-5289. ; 39:12, s. 1601-1624
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Tidskriftsartikel (refereegranskat)abstract
- This study explores first-year university students' reasoning as they learn to draw Lewis structures. We also present a theoretical account of the formal procedure commonly taught for drawing these structures. Students' discussions during problem-solving activities were video recorded and detailed analyses of the discussions were made through the use of practical epistemology analysis (PEA). Our results show that the formal procedure was central for drawing Lewis structures, but its use varied depending on situational aspects. Commonly, the use of individual steps of the formal procedure was contingent on experiences of chemical structures, and other information such as the characteristics of the problem given. The analysis revealed a number of patterns in how students constructed, checked and modified the structure in relation to the formal procedure and the situational aspects. We suggest that explicitly teaching the formal procedure as a process of constructing, checking and modifying might be helpful for students learning to draw Lewis structures. By doing so, the students may learn to check the accuracy of the generated structure not only in relation to the octet rule and formal charge, but also to other experiences that are not explicitly included in the formal procedure.
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| 40. |
- Kokfelt, U., et al.
(författare)
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Diatom blooms and associated vegetation shifts in a subarctic peatland : responses to distant volcanic eruptions?
- 2016
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Ingår i: Journal of Quaternary Science. - : Wiley. - 0267-8179 .- 1099-1417. ; 31:7, s. 723-730
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Tidskriftsartikel (refereegranskat)abstract
- We test the hypothesis that rich occurrences of diatoms observed at transitions between major peat units representing different vegetation communities in a peat sequence from subarctic northern Sweden reflect responses to acid deposition from the Samalas AD 1257 and Laki AD 1783/1784 eruptions. We observe sudden changes in the mire ecosystem and thereby in the trophic status and biogeochemical cycling of the peatland. Both the eruptions are known to have been associated with significant acid deposition events and climatic anomalies, as recorded in polar ice cores. To test the hypothesis, new chronological analyses and age modelling were applied to existing biogeochemical and biological records from the peat sequence. This approach yielded modelled age ranges of AD 1239-1284 (1s)/AD 1210-1303 (2s) (median: AD 1260) and AD 1674-1795 (1s)/AD 1665-1875 (2s) (median AD 1743), respectively, for the stratigraphic transitions. Hence, the modelled age ranges bracket the ages of the eruptions in question and the hypothesis could therefore not be rejected. Impacts of acid deposition from the eruptions are assumed to have caused instant acidification, vegetation damage, increased nutrient cycling and blooms of opportunistic epiphytic diatoms. In addition, cooling may have contributed to vegetation changes through permafrost inception, frost heave and thereby altered hydrological conditions.
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| 41. |
- Lederman, Judith S., et al.
(författare)
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Completing the progression establishing an international baseline of primary, middle and secondary students’ views of scientific inquiry
- 2023
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Ingår i: International Journal of Science Education. - : Routledge. - 0950-0693 .- 1464-5289.
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Tidskriftsartikel (refereegranskat)abstract
- Knowledge of scientific inquiry (SI) is considered essential to the development of an individual's Scientific Literacy (SL) and therefore, SI is included in many international science education reform documents. Two previous large scale international studies assessed the SI understandings of students entering middle school and secondary students at the end of their formal K-12 science education. The purpose of this international project was to use the VASI-E to collect data on what primary level students have learned about SI in their first few years of school. This study adds to previous research to bridge the landscape of SI understandings now with representation from primary, middle and high school samples. A total of 4,238 students from 35 countries/regions spanning six continents participated in the study. The results show that globally, primary students are not adequately informed about SI for their age group. However, when compared with the students in the previous international studies (grades seven and 12), the primary students' understandings were surprisingly closer to the levels of understanding of SI of the secondary school students than those in the seventh grade study.
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| 42. |
- Loisel, Julie, et al.
(författare)
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A database and synthesis of northern peatland soil properties and Holocene carbon and nitrogen accumulation
- 2014
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Ingår i: The Holocene. - : SAGE Publications. - 0959-6836 .- 1477-0911. ; 24:9, s. 1028-1042
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Tidskriftsartikel (refereegranskat)abstract
- Here, we present results from the most comprehensive compilation of Holocene peat soil properties with associated carbon and nitrogen accumulation rates for northern peatlands. Our database consists of 268 peat cores from 215 sites located north of 45 degrees N. It encompasses regions within which peat carbon data have only recently become available, such as the West Siberia Lowlands, the Hudson Bay Lowlands, Kamchatka in Far East Russia, and the Tibetan Plateau. For all northern peatlands, carbon content in organic matter was estimated at 42 +/- 3% (standard deviation) for Sphagnum peat, 51 +/- 2% for non-Sphagnum peat, and at 49 +/- 2% overall. Dry bulk density averaged 0.12 +/- 0.07 g/cm(3), organic matter bulk density averaged 0.11 +/- 0.05 g/cm(3), and total carbon content in peat averaged 47 +/- 6%. In general, large differences were found between Sphagnum and non-Sphagnum peat types in terms of peat properties. Time-weighted peat carbon accumulation rates averaged 23 +/- 2 (standard error of mean) g C/m(2)/yr during the Holocene on the basis of 151 peat cores from 127 sites, with the highest rates of carbon accumulation (25-28 g C/m(2)/yr) recorded during the early Holocene when the climate was warmer than the present. Furthermore, we estimate the northern peatland carbon and nitrogen pools at 436 and 10 gigatons, respectively. The database is publicly available at https://peatlands.lehigh.edu.
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| 43. |
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| 44. |
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| 45. |
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| 46. |
- Moen, V, et al.
(författare)
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Hyponatremia complicating labour-rare or unrecognised? A prospective observational study
- 2009
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Ingår i: BJOG-AN INTERNATIONAL JOURNAL OF OBSTETRICS AND GYNAECOLOGY. - : Wiley. - 1470-0328 .- 1471-0528. ; 116:4, s. 552-561
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to investigate the occurrence of hyponatraemia following delivery, with a hypothesis that hyponatraemia has a high prevalence in labouring women. Prospective observational study. Consultant-led delivery suite in County Hospital, Kalmar, Sweden. A total of 287 pregnant women at term (37 full gestational weeks). Oral fluids were allowed during labour. Blood samples were collected on admission, after delivery, and from the umbilical artery and vein. Hyponatraemia defined as plasma sodium <= 130 mmol/l after delivery. Hyponatraemia was found in 16 (26%) of the 61 mothers who received more than 2500 ml of fluid during labour. Two-thirds of fluids were orally ingested. Decrease in plasma sodium concentration during labour correlated with duration of labour and the total fluid volume administered. Analysis by multivariate logistic regression showed that hyponatraemia was significantly correlated with fluid volume (P < 0.001) but not with oxytocin administration or epidural analgesia. Hyponatraemia correlated significantly with prolonged second stage of labour, instrumental delivery, and emergency caesarean section for failure to progress (P = 0.002). Hyponatraemia is not uncommon following labour. Tolerance to a water load is diminished during labour; therefore, even moderate fluid volumes may cause hyponatraemia. Women should not be encouraged to drink excessively during labour. Oral fluids, when permitted, should be recorded, and intravenous administration of hypotonic fluids should be avoided. When abundant drinking is unrecognised or intravenous fluid administration liberal, life-threatening hyponatraemia may develop. The possibility that hyponatraemia may influence uterine contractility merits further investigation.
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| 47. |
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| 48. |
- Nascimento, V. B., et al.
(författare)
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Surface-Stabilized Nonferromagnetic Ordering of a Layered Ferromagnetic Manganite
- 2009
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 103:22, s. 227201-
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Tidskriftsartikel (refereegranskat)abstract
- An outstanding question regarding the probing or possible device applications of correlated electronic materials (CEMs) with layered structure is the extent to which their bulk and surface properties differ or not. The broken translational symmetry at the surface can lead to distinct functionality due to the charge, lattice, orbital, and spin coupling. Here we report on the case of bilayered manganites with hole doping levels corresponding to bulk ferromagnetic order. We find that, although the hole doping level is measured to be the same as in the bulk, the surface layer is not ferromagnetic. Further, our low-energy electron diffraction and x-ray measurements show that there is a c-axis collapse in the outermost layer. Bulk theoretical calculations reveal that, even at fixed doping level, the relaxation of the Jahn-Teller distortion at the surface is consistent with the stabilization of an A-type antiferromagnetic state.
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| 49. |
- Pentcheva, R., et al.
(författare)
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A combined DFT/LEED-approach for complex oxide surface structure determination : Fe3O4(001)
- 2008
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Ingår i: Surface Science. - : Elsevier BV. - 0039-6028 .- 1879-2758. ; 602:7, s. 1299-1305
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Tidskriftsartikel (refereegranskat)abstract
- A combination of density functional theory (DFT) calculations and low energy electron diffraction (LEED) analysis is used to determine the surface structure of Fe3O4 0 00). We find that the surface is rich in oxygen and the observed (root 2- x root 2-)R45 degrees reconstruction is a result of a Jahn-Teller distortion as established by recent DFT-calculations [R. Pentcheva, F. Wendler, H.L. Meyerheim, W. Moritz, N. Jedrecy, M. Scheffler, Phys. Rev. Lett. 94 (2005) 126101]. The corresponding Pendry reliability factor is 0.34. Furthermore, we investigate the influence of the preparation conditions (temperature, oxygen pressure) on the LEED intensities of natural and synthetic samples. The electron scattering phase shifts used in the analysis of the LEED spectra are derived from two methods, one based on the DFT electron densities and another employing an overlap of atomic potentials with optimized muffin-tin radii. Both approaches lead to similar results.
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| 50. |
- Robba, Chiara, et al.
(författare)
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Oxygen targets and 6-month outcome after out of hospital cardiac arrest : a pre-planned sub-analysis of the targeted hypothermia versus targeted normothermia after Out-of-Hospital Cardiac Arrest (TTM2) trial
- 2022
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Ingår i: Critical Care. - : Springer Science and Business Media LLC. - 1364-8535 .- 1466-609X. ; 26, s. 1-13
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Tidskriftsartikel (refereegranskat)abstract
- Background: Optimal oxygen targets in patients resuscitated after cardiac arrest are uncertain. The primary aim of this study was to describe the values of partial pressure of oxygen values (PaO2) and the episodes of hypoxemia and hyperoxemia occurring within the first 72 h of mechanical ventilation in out of hospital cardiac arrest (OHCA) patients. The secondary aim was to evaluate the association of PaO2 with patients’ outcome. Methods: Preplanned secondary analysis of the targeted hypothermia versus targeted normothermia after OHCA (TTM2) trial. Arterial blood gases values were collected from randomization every 4 h for the first 32 h, and then, every 8 h until day 3. Hypoxemia was defined as PaO2 < 60 mmHg and severe hyperoxemia as PaO2 > 300 mmHg. Mortality and poor neurological outcome (defined according to modified Rankin scale) were collected at 6 months. Results: 1418 patients were included in the analysis. The mean age was 64 ± 14 years, and 292 patients (20.6%) were female. 24.9% of patients had at least one episode of hypoxemia, and 7.6% of patients had at least one episode of severe hyperoxemia. Both hypoxemia and hyperoxemia were independently associated with 6-month mortality, but not with poor neurological outcome. The best cutoff point associated with 6-month mortality for hypoxemia was 69 mmHg (Risk Ratio, RR = 1.009, 95% CI 0.93–1.09), and for hyperoxemia was 195 mmHg (RR = 1.006, 95% CI 0.95–1.06). The time exposure, i.e., the area under the curve (PaO2-AUC), for hyperoxemia was significantly associated with mortality (p = 0.003). Conclusions: In OHCA patients, both hypoxemia and hyperoxemia are associated with 6-months mortality, with an effect mediated by the timing exposure to high values of oxygen. Precise titration of oxygen levels should be considered in this group of patients. Trial registration: clinicaltrials.gov NCT02908308, Registered September 20, 2016.
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