Potential odour emission measurement in organic fraction of municipal solid waste during anaerobic digestion : relationship with process and biological stability parameters

The aim of the present study is to investigate the correlation between microbial activity, i.e., biological stability measured by aerobic (OD(20) test) and anaerobic tests (ABP test), and odour emissions of organic fraction of municipal solid waste during anaerobic digestion in a full-scale treatment plant considering the three stages of the process (input, digested and post-digested waste). The results obtained indicated that the stabilization of the treated material reduces the odour impact measured by the olfactometric approach. Successive application of gas chromatography mass spectrometry (GC-MS) and electronic nose (EN) allowed the characterization of the different groups of volatile organic compounds (VOCs) responsible of odour impacts determining, also, their concentration. Principal component and partial least squares analyses applied to the EN and GC-MS data sets gave good regression for the OD(20) vs the EN and OD(20) vs the GC-MS data. Therefore, OD(20) reduction could be used as an odour depletion indicator. (C) 2010 Elsevier Ltd. All rights reserved

Fractal Analysis Reveals Reduced Complexity of Retinal Vessels in CADASIL

The Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) affects mainly small cerebral arteries and leads to disability and dementia. The relationship between clinical expression of the disease and progression of the microvessel pathology is, however, uncertain as we lack tools for imaging brain vessels in vivo. Ophthalmoscopy is regarded as a window into the cerebral microcirculation. In this study we carried out an ophthalmoscopic examination in subjects with CADASIL. Specifically, we performed fractal analysis of digital retinal photographs. Data are expressed as mean fractal dimension (mean-D), a parameter that reflects complexity of the retinal vessel branching. Ten subjects with genetically confirmed diagnosis of CADASIL and 10 sex and age-matched control subjects were enrolled. Fractal analysis of retinal digital images was performed by means of a computer-based program, and the data expressed as mean-D. Brain MRI lesion volume in FLAIR and T1-weighted images was assessed using MIPAV software. Paired t-test was used to disclose differences in mean-D between CADASIL and control groups. Spearman rank analysis was performed to evaluate potential associations between mean-D values and both disease duration and disease severity, the latter expressed as brain MRI lesion volumes, in the subjects with CADASIL. The results showed that mean-D value of patients (1.42±0.05; mean±SD) was lower than control (1.50±0.04; p = 0.002). Mean-D did not correlate with disease duration nor with MRI lesion volumes of the subjects with CADASIL. The findings suggest that fractal analysis is a sensitive tool to assess changes of retinal vessel branching, likely reflecting early brain microvessel alterations, in CADASIL patients

β-hairpin-mediated formation of structurally distinct multimers of neurotoxic prion peptides

Protein misfolding disorders are associated with conformational changes in specific proteins, leading to the formation of potentially neurotoxic amyloid fibrils. During pathogenesis of prion disease, the prion protein misfolds into β-sheet rich, protease-resistant isoforms. A key, hydrophobic domain within the prion protein, comprising residues 109–122, recapitulates many properties of the full protein, such as helix-to-sheet structural transition, formation of fibrils and cytotoxicity of the misfolded isoform. Using all-atom, molecular simulations, it is demonstrated that the monomeric 109–122 peptide has a preference for α-helical conformations, but that this peptide can also form β-hairpin structures resulting from turns around specific glycine residues of the peptide. Altering a single amino acid within the 109–122 peptide (A117V, associated with familial prion disease) increases the prevalence of β-hairpin formation and these observations are replicated in a longer peptide, comprising residues 106–126. Multi-molecule simulations of aggregation yield different assemblies of peptide molecules composed of conformationally-distinct monomer units. Small molecular assemblies, consistent with oligomers, comprise peptide monomers in a β-hairpin-like conformation and in many simulations appear to exist only transiently. Conversely, larger assemblies are comprised of extended peptides in predominately antiparallel β-sheets and are stable relative to the length of the simulations. These larger assemblies are consistent with amyloid fibrils, show cross-β structure and can form through elongation of monomer units within pre-existing oligomers. In some simulations, assemblies containing both β-hairpin and linear peptides are evident. Thus, in this work oligomers are on pathway to fibril formation and a preference for β-hairpin structure should enhance oligomer formation whilst inhibiting maturation into fibrils. These simulations provide an important new atomic-level model for the formation of oligomers and fibrils of the prion protein and suggest that stabilization of β-hairpin structure may enhance cellular toxicity by altering the balance between oligomeric and fibrillar protein assemblies

Sexual pheromone or conventional odors increase extracellular lactate without changing glucose utilization in specific brain areas of the rat.

Brain extracellular lactate levels increase following physiological stimuli. Monitoring lactate levels might be a tool for detecting dynamic changes in brain activity. In this study we compared changes of extracellular lactate in selected brain areas with rates of glucose utilization as measured by the [14C]2-deoxyglucose method, following olfactory stimulation. Conventional (green pepper essence, heptanal, exanal, octanal) and, above all, non-conventional (sexual pheromone) odors increased lactate in the rhinencephalum, but not in the striatum. Glucose utilization did not change in any area. This discrepancy may result from the different temporal resolution of the two methods employed and/or from the clearance of lactate, whose tissue content increases transiently following neuronal activation as a reflection of the initial oxygen debt

Mapping neuronal activity of the basal ganglia in experimental models of Parkinson's disease: contributions of the [14C]2-deoxyglucose method.

No abstract availabl