997 resultados para 242-2
Resumo:
Clustering of Pick bodies (PB) was studied in the frontal and temporal lobe in 10 cases of Pick's disease (PD). Pick bodies exhibited clustering in 47/50 (94%) brain areas analysed. In 20/50 (40%) brain areas, PB were present in a single large cluster ≤ 6400 μm in diameter, in 27/50 (54%) PB occurred in smaller clusters (200-3200 μm in diameter) which exhibited a regular periodicity relative to the tissue boundary, in 1/50 (2%) there was a regular distribution of individual PB and in 2/50 (4%), PB were randomly distributed. Mean cluster size of the PB was greater in the dentate gyrus compared with the inferior temporal gyrus and lateral occipitotemporal gyrus. Mean cluster size of PB in a brain region was positively correlated with the mean density of PB. Hence, PB exhibit essentially the same spatial patterns as senile plaques and neurofibrillary tangles in Alzheimer's disease (AD) and Lewy bodies in Dementia with Lewy bodies (DLB).
Resumo:
TEX86 (TetraEther indeX of tetraethers consisting of 86 carbon atoms) is a sea surface temperature (SST) proxy based on the distribution of archaeal isoprenoid glycerol dialkyl glycerol tetraethers (GDGTs). In this study, we appraise the applicability of TEX86 and TEX86L in subpolar and polar regions using surface sediments. We present TEX86 and TEX86L data from 160 surface sediment samples collected in the Arctic, the Southern Ocean and the North Pacific. Most of the SST estimates derived from both TEX86 and TEX86L are anomalously high in the Arctic, especially in the vicinity of Siberian river mouths and the sea ice margin, plausibly due to additional archaeal contributions linked to terrigenous input. We found unusual GDGT distributions at five sites in the North Pacific. High GDGT-0/crenarchaeol and GDGT-2/crenarchaeol ratios at these sites suggest a substantial contribution of methanogenic and/or methanotrophic archaea to the sedimentary GDGT pool here. Apart from these anomalous findings, TEX86 and TEX86L values in the surface sediments from the Southern Ocean and the North Pacific do usually vary with overlaying SSTs. In these regions, the sedimentary TEX86-SST relationship is similar to the global calibration, and the derived temperature estimates agree well with overlaying annual mean SSTs at the sites. However, there is a systematic offset between the regional TEX86L-SST relationships and the global calibration. At these sites, temperature estimates based on the global TEX86L calibration are closer to summer SSTs than annual mean SSTs. This finding suggests that in these subpolar settings a regional TEX86L calibration may be a more suitable equation for temperature reconstruction than the global calibration.
Resumo:
Purpose: To determine acrylamide (AA) levels in different brands of commercial and traditional foodstuffs available in Syria by ultra-performance liquid chromatography-mass spectrometery (UPLCMS). Methods: A total of 63 samples were analyzed. Food samples were defatted by hexane and then extracted with methanol 98 % in a vortex mixer. Thereafter, Carrez I and Carrez II were added to precipitate proteins from the co-extractives and then centrifuged to obtain a clear aqueous extract that was evaporated to dryness. The extract was dissolved in 1 mL of water, eluted through a preconditioned Oasis HLB cartridge and then filtered. The filtrate was analyzed by UPLC-MS/MS to determine AA content. Results: Among the commercial foods tested, the highest acrylamide quantity was found in potato products (396 ± 3.59 – 1844 ± 5.29 μg kg−1) and the lowest in corn products (183 ± 2.64 – 366 ± 4.58 μg kg−1). This was followed by biscuits (57 ± 2.64 – 1433 ± 2.51 μg kg−1), breakfast cereals (121 ± 8.73 – 245 ± 3.60 μg kg−1), bread (119 ± 1.73 – 263 ± 3.60 μg kg−1) and then coffee (113 ± 2.64 - 64 ± 3.05 μg kg−1). Regarding traditional foods, the highest level of AA was found in AL- Mshabak (481 ± 2.08 μg kg−1) and AL-Awamat (421 ± 2.64 μg kg−1) followed by AL-Namora (282 ± 4.35 μg kg−1) and AL-Kenafa (242 ± 2.64 μg kg−1). It was also observed that the lowest amount of AA was in fried bread (230 μg kg−1), AL-Fatayer (192 ± 3.51 μg kg−1) and AL-Baqlawa (172 ± 4.35 μg kg−1) while Eid Aqras (130 ± 4.58 μg kg−1) and AL-Brazeq (167 ± 3.78 μg kg−1) contained the least amount of AA. Conclusion: The results indicate that the highest levels of AA are found in the most commonly consumed foods. There was significant difference (p < 0.05) in AA levels among different food items and within different brands of the same product.
Resumo:
1.The reported inhibition of the succinate oxidase system at high concentrations of dinitrophenol, considered to be at the primary dehydrogenase level, is now confirmed by measuring the activity of succinate dehydrogenase (succinate:(acceptor) oxidoreductase, EC 1.3.99.1) in the presence of dinitrophenol, using the dye reduction method. 2. 2. The results indicate that the inhibition of substrate-activated succinate dehydrogenase by dinitrophenol is competitive. 3. 3. Low concentrations of dinitrophenol inhibited the basal activity, while at higher concentrations the kinetics were complicated by an apparent activation. 4. 4. Preincubation of mitochondria with dinitrophenol stimulated the enzyme activity, a phenomenon shown by succinate and competitive inhibitors. This activation was very rapid at 37°, compared to that by succinate; activation by dinitrophenol was observed even at 25°, under conditions where succinate had no effect. 5. 5. Repeated washing of the activated mitochondrial samples with the sucrose homogenizing medium reduced the succinate-stimulated activity to the basal level, but only partially reversed the dinitrophenol activation. 6. 6. The relevance of this activation phenomenon to the physiological modulation of this enzyme system is discussed.
Resumo:
The effect of Sr doping in CeO2 for its use as solid electrolytes for intermediate temperature solid oxide fuel cells (IT-SOFCs) has been explored here. Ce1-xSrxO2-delta (x = 0.05-0.2) are successfully synthesized by citrate-complexation method. XRD, Raman, FT-IR, FE-SEM/EDX and electrochemical impedance spectra are used for structural and electrical characterizations. The formation of well crystalline cubic fluorite structured solid solution is observed for x = 0.05 based on XRD and Raman spectra. For compositions i.e., x > 0.05, however, a secondary phase of SrCeO3 is confirmed by the peak at 342 cm(-1) in Raman spectra. Although the oxygen ion conductivity was found to decrease with increase in x, based on ac-impedance studies, conductivity of Ce0.95Sr0.05O2-delta was found to be higher than of Ce0.95Gd0.1O2-delta and Ce0.8Gd0.2O2-delta. The decrease in conductivity of Ce1-xSrxO2-delta with increasing dopant concentration is ascribed to formation of impurity phase SrCeO3 as well as the formation of neutral associated pairs, Se `' Ce V-o. The activation energies are found to be 0.77, 0.83, 0.85 and 0.90 eV for x = 0.05, 0.1, 0.15 and 0.20, respectively. (C) 2014 Elsevier B.V. All rights reserved.