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  • Matus, M., et al. (författare)
  • Key Comparison EURAMET.L-K1.2011 Measurement of gauge blocks by interferometry
  • 2016
  • Ingår i: Metrologia. - 0026-1394 .- 1681-7575. ; 53:1A
  • Tidskriftsartikel (refereegranskat)abstract
    • The key comparison EURAMET.L-K1.2011 on gauge blocks was carried out in the framework of a EURAMET project starting in 2012 and ending in 2015. It involved the participation of 24 National Metrology Institutes from Europe and Egypt, respectively. 38 gauge blocks of steel and ceramic with nominal central lengths between 0.5 mm and 500 mm were circulated. The comparison was conducted in two loops with two sets of artifacts. A statistical technique for linking the reference values was applied. As a consequence the reference value of one loop is influenced by the measurements of the other loop although they did not even see the artifacts of the others. This influence comes solely from three "linking laboratories" which measure both sets of artifacts. In total there were 44 results were not fully consistent with the reference values. This represents 10% of the full set of 420 results which is a considerable high number. At least 12 of them are clearly outliers where the participants have been informed by the pilot as soon as possible. The comparison results help to support the calibration and measurement capabilities (CMCs) of the laboratories involved in the CIPM MRA.
  • Lomnytska, Marta, et al. (författare)
  • Platelet protein biomarker panel for ovarian cancer diagnosis
  • 2018
  • Ingår i: BIOMARKER RESEARCH. - : BIOMED CENTRAL LTD. - 2050-7771. ; 6
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Platelets support cancer growth and spread making platelet proteins candidates in the search for biomarkers.Methods: Two-dimensional (2D) gel electrophoresis, Partial Least Squares Discriminant Analysis (PLS-DA), Western blot, DigiWest.Results: PLS-DA of platelet protein expression in 2D gels suggested differences between the International Federation of Gynaecology and Obstetrics (FIGO) stages III-IV of ovarian cancer, compared to benign adnexal lesions with a sensitivity of 96% and a specificity of 88%. A PLS-DA-based model correctly predicted 7 out of 8 cases of FIGO stages I-II of ovarian cancer after verification by western blot. Receiver-operator curve (ROC) analysis indicated a sensitivity of 83% and specificity of 76% at cut-off >0.5 (area under the curve (AUC) = 0.831, p < 0.0001) for detecting these cases. Validation on an independent set of samples by DigiWest with PLS-DA differentiated benign adnexal lesions and ovarian cancer, FIGO stages III-IV, with a sensitivity of 70% and a specificity of 83%.Conclusion: We identified a group of platelet protein biomarker candidates that can quantify the differential expression between ovarian cancer cases as compared to benign adnexal lesions.
  • Sender, Vicky, et al. (författare)
  • Capillary leakage provides nutrients and antioxidants for rapid pneumococcal proliferation in influenza-infected lower airways
  • 2020
  • Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 117:49, s. 31386-31397
  • Tidskriftsartikel (refereegranskat)abstract
    • Influenza A virus (IAV)-related mortality is often due to secondary bacterial infections, primarily by pneumococci. Here, we study how IAV-modulated changes in the lungs affect bacterial replication in the lower respiratory tract (LRT). Bronchoalveolar lavages (BALs) from coinfected mice showed rapid bacterial proliferation 4 to 6 h after pneumococcal challenge. Metabolomic and quantitative proteomic analyses demonstrated capillary leakage with efflux of nutrients and antioxidants into the alveolar space. Pneumococcal adaptation to IAV-induced inflammation and redox imbalance increased the expression of the pneumococcal chaperone/protease HtrA. Presence of HtrA resulted in bacterial growth advantage in the IAV-infected LRT and protection from complement-mediated opsonophagocytosis due to capsular production. Absence of HtrA led to growth arrest in vitro that was partially restored by antioxidants. Pneumococcal ability to grow in the IAV-infected LRT depends on the nutrient-rich milieu with increased levels of antioxidants such as ascorbic acid and its ability to adapt to and cope with oxidative damage and immune clearance.
  • Bagheri, Niusha, et al. (författare)
  • Change in the emission saturation and kinetics of upconversion nanoparticles under different light irradiations
  • 2019
  • Ingår i: Optical materials (Amsterdam). - : Elsevier. - 0925-3467 .- 1873-1252. ; 97
  • Tidskriftsartikel (refereegranskat)abstract
    • Nd3+-sensitized upconversion nanoparticles (UCNPs) can be excited by both 980 and 808 nm light, which is regarded as a particularly advantageous property of these particles. In this work, we demonstrate that the nanoparticles can exhibit significantly different response when excited at these two excitation wavelengths, showing dependence on the intensity of the excitation light and the way it is distributed in time. Specifically, with 808 nm excitation saturation in the emitted luminescence is more readily reached with increasing excitation intensities than upon 980 nm excitation. This is accompanied by delayed upconversion luminescence (UCL) kinetics and weaker UCL intensities. The different luminescence response at 808 and 980 nm excitation reported in this work is relevant in a manifold of applications using UCNPs as labels and sensors. This could also open new possibilities for multi-wavelength excitable UCNPs for upconversion color display and in laser-scanning microscopy providing selective readouts and sub-sectioning of samples.
  • Fröjse, R, et al. (författare)
  • Local metabolic effects of dopexamine on the intestine during mesenteric hypoperfusion.
  • 2004
  • Ingår i: Shock. - 1073-2322 .- 1540-0514. ; 21:3, s. 241-7
  • Tidskriftsartikel (refereegranskat)abstract
    • This self-controlled experimental study was designed to test the hypothesis that dopexamine, a synthetic catecholamine that activates dopaminergic (DA-1) and beta2-adrenergic receptors, improves oxygenation in the jejunal mucosa during intestinal hypotension. In six normoventilated barbiturate-anesthetized pigs, controlled reductions in superior mesenteric arterial pressure (PSMA) was obtained by an adjustable clamp around the artery. Dopexamine infusions (0.5 and 1.0 microg.kg(-1).min(-1)) were administered at a freely variable PSMA (i.e., with the perivascular clamp fully open) and at a PSMA of 50 mmHg and 30 mmHg. We continuously measured superior mesenteric venous blood flow (QMES; transit-time ultrasonic flowmetry), jejunal mucosal perfusion (laser Doppler flowmetry), and tissue oxygen tension (PO2TISSUE; microoximetry). Jejunal luminal microdialysate of lactate, pyruvate, and glucose were measured every 5 min. Measurements of mucosal PCO2 (air tonometry), together with blood sampling and end-tidal PCO2 measurements, enabled calculations of pHi and PCO2 gap. Dopexamine reduced mesenteric vascular resistance and increased QMES at a PSMA of 50 mmHg and 30 mmHg. At a PSMA of 30 mmHg, dopexamine increased mesenteric oxygen delivery but did not influence mesenteric oxygen uptake or extraction. In this situation, dopexamine had no beneficial effect on jejunal mucosal blood flow. On the contrary, dopexamine increased mesenteric net lactate production and PCO2 gap, whereas PO2TISSUE and pHi decreased. Jejunal luminal microdialysate data demonstrated an increased lactate concentration and a pattern of decreased glucose concentration and increased luminal lactate-pyruvate ratio. These negative metabolic effects of dopexamine should be taken into account in situations of low perfusion pressures.
  • Johnsson, Markus, et al. (författare)
  • Adsorption of a PEO-PPO-PEO triblock copolymer on small unilamellar vesicles : equilibrium and kinetic properties and correlation with membrane permeability
  • 2001
  • Ingår i: Langmuir. - 0743-7463 .- 1520-5827. ; 17:13, s. 3902-3911
  • Tidskriftsartikel (refereegranskat)abstract
    • The adsorption of the triblock copolymer F127, poly(ethylene oxide)−poly(propylene oxide)−poly(ethylene oxide), EO98PO67EO98, onto immobilized small unilamellar vesicles (SUVs) of egg phosphatidylcholine (EPC) has been studied by means of a quartz crystal microbalance (QCM). With this technique we first show that SUVs of EPC adsorb on gold to form a monolayer of vesicles. This supported monolayer of vesicles was then used to follow the adsorption of the F127 polymer onto the lipid membrane surface. The adsorption of F127 was found to be a rapid process, and the measured polymer binding isotherm was fitted to a Freundlich type of isotherm. The maximum, or plateau, adsorbed amount was determined to be of a magnitude similar to that found for adsorption of F127 on hydrophobic surfaces. Furthermore, the desorption of the triblock copolymers from the membrane surface was followed after rinsing the SUV monolayer with pure buffer. It was found that the desorption process displayed essentially the same rapid kinetics as the adsorption process, indicating a weak interaction between the polymers and the lipid membrane. The determined polymer binding isotherm was used to correlate the adsorbed amount of polymer with the polymer-induced leakage of carboxy fluorescein (CF) from the SUVs. It was found that the membrane permeability was increased severalfold already at low surface coverage and that the maximum magnitude of the CF release rate was obtained at, or close to, F127 concentrations giving rise to the maximum adsorbed amount of polymer. In addition, the increased membrane permeability induced by the triblock copolymers was compared with the effect of adding a conventional ethylene oxide (EO) surfactant, Triton X-100, to the SUVs. The result emphasizes the dramatic effect of F127 on the bilayer permeability.
  • Sjöholm, Johannes, et al. (författare)
  • The lateral distance between a proton pump and ATP synthase determines the ATP-synthesis rate
  • 2017
  • Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 7
  • Tidskriftsartikel (refereegranskat)abstract
    • We have investigated the effect of lipid composition on interactions between cytochrome bo(3) and ATP-synthase, and the ATP-synthesis activity driven by proton pumping. The two proteins were labeled by fluorescent probes and co-reconstituted in large (d congruent to 100 nm) or giant (d congruent to 10 mu m) unilamellar lipid vesicles. Interactions were investigated using fluorescence correlation/cross-correlation spectroscopy and the activity was determined by measuring ATP production, driven by electron-proton transfer, as a function of time. We found that conditions that promoted direct interactions between the two proteins in the membrane (higher fraction DOPC lipids or labeling by hydrophobic molecules) correlated with an increased activity. These data indicate that the ATP-synthesis rate increases with decreasing distance between cytochrome bo3 and the ATP-synthase, and involves proton transfer along the membrane surface. The maximum distance for lateral proton transfer along the surface was found to be similar to 80 nm.
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  • Resultat 1-10 av 11
  • [1]2Nästa

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