| 1. |
- Wohlfahrt, Georg, et al.
(författare)
-
Biotic, Abiotic, and Management Controls on the Net Ecosystem CO2 Exchange of European Mountain Grassland Ecosystems
- 2008
-
Ingår i: Ecosystems. - : Springer Science and Business Media LLC. - 1432-9840 .- 1435-0629. ; 11:8, s. 1338-1351
-
Tidskriftsartikel (refereegranskat)abstract
- was spring and autumn for the sites characterized by summer droughts (southern sites) and (peak) summer for the Alpine and northern study sites. This general pattern was interrupted by grassland management practices, that is, mowing and grazing, when the variability in NEE explained by PPFD decreased in concert with the amount of aboveground biomass (BMag). Temperature was the abiotic influence factor that explained most of the variability in ecosystem respiration at the Alpine and northern study sites, but not at the southern sites characterized by a pronouncedThe net ecosystem carbon dioxide (CO2) exchange (NEE) of nine European mountain grassland ecosystems was measured during 2002-2004 using the eddy covariance method. Overall, the availability of photosynthetically active radiation (PPFD) was the single most important abiotic influence factor for NEE. Its role changed markedly during the course of the season, PPFD being a better predictor for NEE during periods favorable for CO2 uptake, which summer drought, where soil water availability and the amount of aboveground biomass were more or equally important. The amount of assimilating plant area was the single most important biotic variable determining the maximum ecosystem carbon uptake potential, that is, the NEE at saturating PPFD. Good correspondence, in terms of the magnitude of NEE, was observed with many (semi-) natural grasslands around the world, but not with grasslands sown on fertile soils in lowland locations, which exhibited higher maximum carbon gains at lower respiratory costs. It is concluded that, through triggering rapid changes in the amount and area of the aboveground plant matter, the timing and frequency of land management practices is crucial for the short-term sensitivity of the NEE of the investigated mountain grassland ecosystems to climatic drivers.
|
|
| 2. |
- Kovacs, Gabor G., et al.
(författare)
-
Mixed brain pathologies in dementia : the BrainNet Europe consortium experience
- 2008
-
Ingår i: Dementia and Geriatric Cognitive Disorders. - : S. Karger AG. - 1420-8008 .- 1421-9824. ; 26:4, s. 343-350
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Dementia results from heterogeneous diseases of the brain. Mixed disease forms are increasingly recognized. METHODS: We performed a survey within brain banks of BrainNet Europe to estimate the proportion of mixed disease forms underlying dementia and age- and gender-specific influences. RESULTS: Data collected in 9 centres from 3,303 individuals were analysed. The proportion of patients with mixed diagnoses among all cases with Alzheimer disease (AD), vascular pathology (VP), argyrophilic grain dementia (AGD), and synucleinopathies, such as Lewy body dementia (LBD), Parkinson disease (PD) and synuclein pathology only in the amygdala, was 53.3%. Mixed pathology was more frequently reported with LBD, PD, AGD, and VP than with AD. The percentage of mixed diagnoses for AGD and VP significantly differed between centres. In patients younger than 75 years, synucleinopathies, and pure forms of AD, VP, and AGD were more frequent in men. Above 75 years of age, more women had pure AD and pure AGD. CONCLUSIONS: The most obvious neuropathological alteration should not terminate the diagnostic procedure since copathology is likely to be found. Neuropathological interpretation of AGD and VP has not been sufficiently established in a consensus. Pure forms of synucleinopathies are unlikely sole substrates for dementia.
|
|
| 3. |
|
|
| 4. |
- Nagy, Zoltán
(författare)
-
Long term magnetic resonance imaging : follow up after preterm birth
- 2009
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Since the introduction of neonatal intensive care units, the survival after preterm birth has improved drastically and development after preterm birth has become an area of intense research. Many studies have found increased rates of neonatal and long term morbidity. In particular, preterm birth has been identified as a risk factor for cognitive and structural brain development and cardiovascular diseases. However, it is also appreciated that the outcome after preterm birth depends on antenatal, neonatal and postnatal care. Aims: The aims of these studies were twofold: to use a range of MRI imaging techniques to investigate whether preterm born children and adolescents show differences in structural brain and aortic development as well as to compare these results to those reported from other countries, involving similar cohorts. Subjects & Methods: The volunteers of interest in these studies were participants in the Stockholm Neonatal Project, which was initiated in 1988 as a prospective follow up study and included preterm infants if their weight at birth was less than or equal to 1500g. At 5½ years of age a group of term born children were selected as a control group. In a pilot study (Paper V) a subgroup of these individuals were examined. Papers I IV involve those 74 out of 182 ex preterm and 69 out of 125 control adolescents that were willing to participate. The participants underwent cranial MRI examinations at the MR Center at the Karolinska University Hospital to collect 3D anatomical images and diffusion tensor imaging data. In a subgroup of individuals, images were also collected of the descending aorta. Results: In all studies we found preterm birth to be a risk factor for long term development. Ex preterm adolescents possessed more structural brain abnormalities mostly in the form of gliosis and white matter loss (Paper I). Their grey and white matter volumes were also lower with the most preterm showing the largest deviations from that of control adolescents (Paper II). Ex preterm adolescents also possessed large areas of thinner cortex (Paper III), hindered white matter microstructure (Papers II and V) and smaller diameters within their descending aortas (Paper IV). Discussion: While these findings are not unprecedented, we found that with respect to brain the severity and extent of these findings was milder than that based on similar cohorts. It may be that the care provided to the preterm infants in the prenatal and neonatal periods resulted in these relatively moderate findings. Should that be the case, it is hopeful that further research will identify the appropriate care such that preterm born individuals may one day develop identically to those born at term.
|
|
| 5. |
- Nagy, Zoltan, et al.
(författare)
-
Structural Correlates of Preterm Birth in the Adolescent Brain
- 2009
-
Ingår i: Pediatrics. - : American Academy of Pediatrics. - 0031-4005 .- 1098-4275. ; 124:5, s. e964-e972
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: The Stockholm Neonatal Project involves a prospective,cross-sectional, population-based, cohort monitored for 12 to17 years after birth; it was started with the aim of investigatingthe long-term structural correlates of preterm birth and comparingfindings with reports on similar cohorts.METHODS: High-resolution anatomic and diffusion tensor imagingdata measuring diffusion in 30 directions were collected byusing a 1.5-T MRI scanner. A total of 143 adolescents (12.18–17.7years of age) participated in the study, including 74 formerlypreterm infants with birth weights of 1500 g (range: 645–1486g) and 69 term control subjects. The 2 groups were well matchedwith respect to demographic and socioeconomic data. The anatomicMRI data were used for calculation of total brain volumes andvoxelwise comparison of gray matter (GM) volumes. The diffusiontensor imaging data were used for voxelwise comparison of whitematter (WM) microstructural integrity.RESULTS: The formerly preterm individuals possessed 8.8% smallerGM volume and 9.4% smaller WM volume. The GM and WM volumesof individuals depended on gestational age and birth weight.The reduction in GM could be attributed bilaterally to the temporallobes, central, prefrontal, orbitofrontal, and parietal cortices,caudate nuclei, hippocampi, and thalami. Lower fractional anisotropywas observed in the posterior corpus callosum, fornix, and externalcapsules.CONCLUSIONS: Although preterm birth was found to be a risk factorregarding long-term structural brain development, the outcomewas milder than in previous reports. This may be attributableto differences in social structure and neonatal care practices.
|
|
| 6. |
- Purgel, Mihály, et al.
(författare)
-
Glyphosate complexation to aluminium(III). An equilibrium and structural study in solution using potentiometry, multinuclear NMR, ATR-FTIR, ESI-MS and DFT calculations
- 2009
-
Ingår i: Journal of Inorganic Biochemistry. - : Elsevier. - 0162-0134 .- 1873-3344. ; 103:11, s. 1426-1438
-
Tidskriftsartikel (refereegranskat)abstract
- The stoichiometries and stability constants of a series of Al(3+)-N-phosponomethyl glycine (PMG/H(3)L) complexes have been determined in acidic aqueous solution using a combination of precise potentiometric titration data, quantitative (27)Al and (31)P NMR spectra, ATR-FTIR spectrum and ESI-MS measurements (0.6M NaCl, 25 degrees C). Besides the mononuclear AlH(2)L(2+), Al(H(2)L)(HL), Al(HL)(2)(-) and Al(HL)L(2-), dimeric Al(2)(HL)L(+) and trinuclear Al(3)H(5)L(4)(2+) complexes have been postulated. (1)H and (31)P NMR data show that different isomers co-exist in solution and the isomerization reactions are slow on the (31)P NMR time scale. The geometries of monomeric and dimeric complexes likely double hydroxo bridged and double phosphonate bridged isomers have been optimized using DFT ab initio calculations starting from rational structural proposals. Energy calculations using the PCM solvation method also support the co-existence of isomers in solutions.
|
|
