| 1. |
- Környei, Bálint S., et al.
(författare)
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Cerebral microbleeds may be less detectable by susceptibility weighted imaging MRI from 24 to 72 hours after traumatic brain injury
- 2021
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Ingår i: Frontiers in Neuroscience. - : Frontiers Media S.A.. - 1662-4548 .- 1662-453X. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: A former rodent study showed that cerebral traumatic microbleeds (TMBs) may temporarily become invisible shortly after injury when detected by susceptibility weighted imaging (SWI). The present study aims to validate this phenomenon in human SWI.Methods: In this retrospective study, 46 traumatic brain injury (TBI) patients in various forms of severity were included and willingly complied with our strict selection criteria. Clinical parameters potentially affecting TMB count, Rotterdam and Marshall CT score, Mayo Clinic Classification, contusion number, and total volume were registered. The precise time between trauma and MRI [5 h 19 min to 141 h 54 min, including SWI and fluid-attenuated inversion recovery (FLAIR)] was individually recorded; TMB and FLAIR lesion counts were assessed. Four groups were created based on elapsed time between the trauma and MRI: 0-24, 24-48, 48-72, and >72 h. Kruskal-Wallis, ANOVA, Chi-square, and Fisher's exact tests were used to reveal differences among the groups within clinical and imaging parameters; statistical power was calculated retrospectively for each comparison.Results: The Kruskal-Wallis ANOVA with Conover post hoc analysis showed significant (p = 0.01; 1-β > 0.9) median TMB number differences in the subacute period: 0-24 h = 4.00 (n = 11); 24-48 h = 1 (n = 14); 48-72 h = 1 (n = 11); and 72 h ≤ 7.5 (n = 10). Neither clinical parameters nor FLAIR lesions depicted significant differences among the groups.Conclusion: Our results demonstrate that TMBs on SWI MRI may temporarily become less detectable at 24-72 h following TBI.
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| 2. |
- Toth, Luca, et al.
(författare)
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Age-related decline in circulating IGF-1 associates with impaired neurovascular coupling responses in older adults
- 2022
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Ingår i: GeroScience. - : Springer. - 2509-2715 .- 2509-2723. ; 44:6, s. 2771-2783
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Tidskriftsartikel (refereegranskat)abstract
- Impairment of moment-to-moment adjustment of cerebral blood flow (CBF) to the increased oxygen and energy requirements of active brain regions via neurovascular coupling (NVC) contributes to the genesis of age-related cognitive impairment. Aging is associated with marked deficiency in the vasoprotective hormone insulin-like growth factor-1 (IGF-1). Preclinical studies on animal models of aging suggest that circulating IGF-1 deficiency is causally linked to impairment of NVC responses. The present study was designed to test the hypotheses that decreases in circulating IGF-1 levels in older adults also predict the magnitude of age-related decline of NVC responses. In a single-center cross-sectional study, we enrolled healthy young (n = 31, 11 female, 20 male, mean age: 28.4 + / - 4.2 years) and aged volunteers (n = 32, 18 female, 14 male, mean age: 67.9 + / - 4.1 years). Serum IGF-1 level, basal CBF (phase contrast magnetic resonance imaging (MRI)), and NVC responses during the trail making task (with transcranial Doppler sonography) were assessed. We found that circulating IGF-1 levels were significantly decreased with age and associated with decreased basal CBF. Age-related decline in IGF-1 levels predicted the magnitude of age-related decline in NVC responses. In conclusion, our study provides additional evidence in support of the concept that age-related circulating IGF-1 deficiency contributes to neurovascular aging, impairing CBF and functional hyperemia in older adults.
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| 3. |
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| 4. |
- Bohus, Veronika, et al.
(författare)
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Microbiological investigation of an industrial ultra pure supply water plant using cultivation-based and cultivation-independent methods
- 2010
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Ingår i: Water Research. - : Elsevier BV. - 0043-1354 .- 1879-2448. ; 44:20, s. 6124-6132
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Tidskriftsartikel (refereegranskat)abstract
- Ultra pure waters (UPW), characterized by extremely low salt and nutrient concentrations, can suffer from microbial contamination which causes biofouling and biocorrosion, possibly leading to reduced lifetime and increased operational costs. Samples were taken from an ultra pure supply water producing plant of a power plant. Scanning electron microscopic examination was carried out on the biofilms formed in the system. Biofilm, ion exchange resin, and water samples were characterized by culture-based methods and molecular fingerprinting (terminal restriction fragment length polymorphism [T-RFLP] analysis and molecular cloning). Identification of bacteria was based on 16S rDNA sequence comparison. A complex microbial community structure was revealed. Nearly 46% of the clones were related to as yet uncultured bacteria. The community profiles of the water samples were the most diverse and most of bacteria were recruited from bacterial communities of tube surface and ion exchange resin biofilms. Microbiota of different layers of the mixed bed ion exchange resin showed the highest similarity. Most of the identified taxa (dominated by β-Proteobacteria) could take part in microbially influenced corrosion. © 2010 Elsevier Ltd.
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| 5. |
- Chen, Yuxi, et al.
(författare)
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Global Three-Dimensional Simulation of Earth's Dayside Reconnection Using a Two-Way Coupled Magnetohydrodynamics With Embedded Particle-in-Cell Model : Initial Results
- 2017
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Ingår i: Journal of Geophysical Research - Space Physics. - : AMER GEOPHYSICAL UNION. - 2169-9380 .- 2169-9402. ; 122:10, s. 10318-10335
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Tidskriftsartikel (refereegranskat)abstract
- We perform a three-dimensional (3-D) global simulation of Earth's magnetosphere with kinetic reconnection physics to study the flux transfer events (FTEs) and dayside magnetic reconnection with the recently developed magnetohydrodynamics with embedded particle-in-cell model. During the 1 h long simulation, the FTEs are generated quasi-periodically near the subsolar point and move toward the poles. We find that the magnetic field signature of FTEs at their early formation stage is similar to a "crater FTE," which is characterized by a magnetic field strength dip at the FTE center. After the FTE core field grows to a significant value, it becomes an FTE with typical flux rope structure. When an FTE moves across the cusp, reconnection between the FTE field lines and the cusp field lines can dissipate the FTE. The kinetic features are also captured by our model. A crescent electron phase space distribution is found near the reconnection site. A similar distribution is found for ions at the location where the Larmor electric field appears. The lower hybrid drift instability (LHDI) along the current sheet direction also arises at the interface of magnetosheath and magnetosphere plasma. The LHDI electric field is about 8 mV/m, and its dominant wavelength relative to the electron gyroradius agrees reasonably with Magnetospheric Multiscale (MMS) observations.
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| 6. |
- Chen, Yuxi, et al.
(författare)
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Magnetohydrodynamic With Embedded Particle-In-Cell Simulation of the Geospace Environment Modeling Dayside Kinetic Processes Challenge Event
- 2020
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Ingår i: Earth and Space Science. - : American Geophysical Union (AGU). - 2333-5084. ; 7:11
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Tidskriftsartikel (refereegranskat)abstract
- We use the magnetohydrodynamic (MHD) with embedded particle-in-cell model (MHD-EPIC) to study the Geospace Environment Modeling (GEM) dayside kinetic processes challenge event at 01:50-03:00 UT on 18 November 2015, when the magnetosphere was driven by a steady southward interplanetary magnetic field (IMF). In the MHD-EPIC simulation, the dayside magnetopause is covered by a PIC code so that the dayside reconnection is properly handled. We compare the magnetic fields and the plasma profiles of the magnetopause crossing with the MMS3 spacecraft observations. Most variables match the observations well in the magnetosphere, in the magnetosheath, and also during the current sheet crossing. The MHD-EPIC simulation produces flux ropes, and we demonstrate that some magnetic field and plasma features observed by the MMS3 spacecraft can be reproduced by a flux rope crossing event. We use an algorithm to automatically identify the reconnection sites from the simulation results. It turns out that there are usually multiple X-lines at the magnetopause. By tracing the locations of the X-lines, we find that the typical moving speed of the X-line endpoints is about 70 km/s, which is higher than but still comparable with the ground-based observations.
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| 7. |
- Daldorff, Lars K. S., et al.
(författare)
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Two-way coupling of a global Hall magnetohydrodynamics model with a local implicit particle-in-cell model
- 2014
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Ingår i: Journal of Computational Physics. - : Elsevier BV. - 0021-9991 .- 1090-2716. ; 268, s. 236-254
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Tidskriftsartikel (refereegranskat)abstract
- Computational models based on a fluid description of the plasma, such as magnetohydrodynamic (MHD) and extended magnetohydrodynamic (XMHD) codes are highly efficient, but they miss the kinetic effects due to the assumptions of small gyro radius, charge neutrality, and Maxwellian thermal velocity distribution. Kinetic codes can properly take into account the kinetic effects, but they are orders of magnitude more expensive than the fluid codes due to the increased degrees of freedom. If the fluid description is acceptable in a large fraction of the computational domain, it makes sense to confine the kinetic model to the regions where kinetic effects are important. This coupled approach can be much more efficient than a pure kinetic model. The speed up is approximately the volume ratio of the full domain relative to the kinetic regions assuming that the kinetic code uses a uniform grid. This idea has been advocated by [1] but their coupling was limited to one dimension and they employed drastically different grid resolutions in the fluid and kinetic models. We describe a fully two-dimensional two-way coupling of a Hall MHD model BATS-R-US with an implicit Particle-in-Cell (PIC) model iPIC3D. The coupling can be performed with identical grid resolutions and time steps. We call this coupled computational plasma model MHD-EPIC (MHD with Embedded PIC regions). Our verification tests show that MHD-EPIC works accurately and robustly. We show a two-dimensional magnetosphere simulation as an illustration of the potential future applications of MHD-EPIC.
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| 8. |
- Escaned, Javier, et al.
(författare)
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Applied coronary physiology for planning and guidance of percutaneous coronary interventions. A clinical consensus statement from the European Association of Percutaneous Cardiovascular Interventions (EAPCI) of the European Society of Cardiology
- 2023
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Ingår i: EuroIntervention. - : Europa Digital & Publishing. - 1774-024X .- 1969-6213. ; 19:6, s. 464-
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Tidskriftsartikel (refereegranskat)abstract
- The clinical value of fractional flow reserve and non-hyperaemic pressure ratios are well established in determining an indication for percutaneous coronary intervention (PCI) in patients with coronary artery disease (CAD). In addition, over the last 5 years we have witnessed a shift towards the use of physio-logy to enhance procedural planning, assess post-PCI functional results, and guide PCI optimisation. In this regard, clinical studies have reported compelling data supporting the use of longitudinal vessel analysis, obtained with pressure guidewire pullbacks, to better understand how obstructive CAD contributes to myocardial ischaemia, to establish the likelihood of functionally successful PCI, to identify the presence and location of residual flow-limiting stenoses and to predict long-term outcomes. The introduction of new functional coronary angiography tools, which merge angiographic information with fluid dynamic equations to deliver information equivalent to intracoronary pressure measurements, are now available and potentially also applicable to these endeavours. Furthermore, the ability of longitudinal vessel analysis to predict the functional results of stenting has played an integral role in the evolving field of simulated PCI. Nevertheless, it is important to have an awareness of the value and challenges of physiology-guided PCI in specific clinical and anatomical contexts. The main aim of this European Association of Percutaneous Cardiovascular Interventions clinical consensus statement is to offer up-to-date evidence and expert opin-ion on the use of applied coronary physiology for procedural PCI planning, disease pattern recognition and post-PCI optimisation.
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| 9. |
- Hansson, Bill S., et al.
(författare)
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Electrophysiological and chemical analysis of sex pheromone communication system of the mottled umber, Erannis defoliaria (Lepidoptera : Geometridae)
- 1990
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Ingår i: Journal of Chemical Ecology. - 0098-0331. ; 16:6, s. 1887-1897
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Tidskriftsartikel (refereegranskat)abstract
- (Z,Z,Z)-3,6,9-nonadecatriene (Z3, Z6, Z9-19Hy) and (Z,Z)-3,9-cis-6,7-epoxy-nonadecadiene (Z3, Z9-cis-6,7-epo-19Hy) were identified in pheromone gland extracts from female Erannis defoliaria. The two components were found in a 1:3 ratio, with the main component, Z3, Z9-cis-6,7-epo-19Hy present at an amount of about 1.5 ng per female. The components were identified by means of gas chromatography-mass spectrometry, gas chromatography-electroantennography and gas chromatography-single sensillum recordings. Single sensillum measurements on the male antenna showed two physiological types of sensilla. One type was characterized by a large spike amplitude cell responding to Z3, Z9-cis-6,7-epoxy-19Hy and a small spike amplitude cell responding to Z3, Z6, Z9-19Hy. A second type responded only with a large spike amplitude cell to the epoxide, and this cell was inhibited by the triene. Of the two pheromone components, the epoxide gave the higher response in the EAG tests. Preliminary field tests support the identification of the pheromone components. The epoxide was also found to be present in the extract of the pheromone gland of Colotois pennaria, and males of C. pennaria and Agriopis marginaria were trapped by the mixture of the identified compounds.
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| 10. |
- Hansson, Bill S., et al.
(författare)
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Pheromone variation among eastern European and a western Asian population of the turnip moth Agrotis segetum
- 1990
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Ingår i: Journal of Chemical Ecology. - 0098-0331. ; 16:5, s. 1611-1622
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Tidskriftsartikel (refereegranskat)abstract
- The female sex pheromone composition and the male electro-physiological response with respect to the three main sex pheromone components, (Z)-5-decenyl acetate, (Z)-7-dodecenyl acetate, and (Z)-9-tetradecenyl acetate, were investigated in populations of Agrotis segetum from Armenia and Bulgaria. The percentage composition of the female-produced pheromone was 1:52:47 and 1:42:57 for the respective populations. Corresponding male receptor frequencies were 9:90:1 and 6:92:2. EAG response profiles of the male antennae were similar for the two populations. The populations from Armenia and Bulgaria differed from the earlier investigated French and Swedish populations, which have larger amounts of (Z)-5-decenyl acetate in gland extracts and have a majority of (Z)-5-decenyl acetate-sensitive receptors. Investigation of receptor frequencies on antennae of male Hungarian moths showed that individuals could be classified as either Swedish or Armenian/Bulgarian type. Males of the Swedish type were preferentially attracted to the three-component pheromone blend, whereas blends of (Z)-7-dodecenyl and (Z)-9-tetradecenyl acetate, and (Z)-7-dodecenol [pure or in mixture with (Z)-5-decenol] attracted the Armenian/Bulgarian type. The nature of pheromone variation among European and Asian populations of the turnip moth and possible mechanisms maintaining the variation are discussed.
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