A method for functional magnetic resonance imaging of olfaction

A method for generating olfactory stimuli for humans within a functional magnetic resonance imaging (fMRI) experimental design is described. The system incorporates a nasal-mask in which the change from odorant to no-odorant conditions occurs in less than 500 ms and is not accompanied by visual, auditory, tactile, or thermal cues. The mask provides an ordorant-free environment following prolonged ordorant presence. Specific imaging parameters that are conducive to the study of the human olfactory system are described. In a pilot study performed using these methods, the specific patterns of activation observed converged with published experimental and clinical findings.     

Evidence for two types of spatial representations: Hemispheric specialization for categorical and coordinate relations.

Analyses of human object recognition abilities led to the hypothesis that 2 kinds of spatial relation representations are used in human vision. Evidence for the distinction between abstract categorical spatial relation representations and specific coordinate spatial relation representations was provided in 4 experiments. These results indicate that Ss make categorical judgments—on/off, left/right, and above/below—faster when stimuli are initially presented to the left cerebral hemisphere, whereas they make evaluations of distance—in relation to 2 mm, 3 mm, or 1 in. (2.54 cm)—faster when stimuli are initially presented to the right cerebral hemisphere. In addition, there was evidence that categorical representations developed with practice. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence of electroosmotic treatment on the hydro-mechanical behaviour of clayey silts: preliminary experimental results

Preliminary results of an investigation focused on the influence of electrokinetic treatment on the mechanical and hydraulic behaviour of clayey soils are presented. The experimental programme aims at providing a contribution to the sustainability of contaminant extraction or containment via electroosmosis. Changes in the hydraulic and mechanical properties of two illitic clayey soils, subjected to a DC electric field, were investigated. Samples of the two soils were subjected to electrokinetic filtration, for different periods of time, and under different constant loads. Afterwards, they were tested under one-dimensional compression to detect changes in stiffness and hydraulic conductivity due to the electrical treatment. After the application of a DC field for a few hours, a small reversible increment in the average soil stiffness was observed, with respect to the untreated soil, while the hydraulic conductivity was not affected substantially. Dramatic changes of the mechanical and hydraulic soil properties, correlated to changes of the soil pH, were observed following non-conditioned electrokinetic treatment with duration of the order of days.     

The Role of the Prefrontal Cortex in the Maintenance of Verbal Working Memory: An Event-Related fMRI Analysis.

Neuroimaging studies have been inconclusive in characterizing the role of the prefrontal cortex (PFC) for maintaining increasingly larger amounts of information in working memory (WM). To address this question, the authors collected event-related functional MRI data while participants performed an item-recognition task in which the number of to-be-remembered letters was parametrically modulated. During maintenance of information in WM, the dorsolateral and the ventrolateral PFC exhibited linearly increasing activation in response to increasing WM load. Prefrontal regions could not be distinguished from one another on the basis of load sensitivity, but the dorsolateral PFC had stronger functional connectivity with the parietal and motor cortex than the ventrolateral PFC. These results suggest an increasingly important role for the PFC in actively maintaining information as the amount of that information increases. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hepatitis a virus and poliovirus 1 inactivation in estuarine water

The hepatitis A virus (HAV) and poliovirus 1 were added to estuarine water samples and their stability in maintenance medium was compared to that in water samples untreated and treated by heat and filtration. The inactivation curves show that the inactivating factor is biological in nature.     

Novel acylflavones from Sideritis syriaca ssp. syriaca

In the framework of the detailed phytochemical analysis of the aerial parts of Sideritis syriaca, two novel acylflavones were isolated together with three acetylated flavone glycosides and acylated flavone glycosides. The novel acylflavones were identified as isoscutellarein 7-trans-p-coumarate and apigenin 7-,4′-bis(trans-p-coumarate). Their structures were elucidated by means of UV, 1D and 2D NMR, LC–DAD–MS and confirmed by HR-MS spectroscopy.     

Depuration of Mytilus galloprovincialis experimentally contaminated with hepatitis A virus

Mussels (Mytilus galloprovincialis) were contaminated with known amounts of laboratory strains of hepatitis A virus and Poliovirus 1 and the effectiveness of a self-cleansing mechanism was studied using a pilot depuration system. Both viruses were rapidly bioaccumulated by mussels and the maximal concentration of about 10(4) TCID50/ml was reached within 1.5 hours. Depuration was carried out up to 24 h; infectivity titer decreased to 10(2) TCID50/ml and 10(3.2) TCID50/ml within 6 h in hepatitis A virus and Poliovirus 1 contaminated mussels, respectively, but only a very slight further decrease was obtained after 24 h. E. coli was used as a control; within 24 h the concentration decreased from 40 to 2 bacteria/ml of mussel (MPN). The elimination of bacteria is not a reliable parameter to control the effectiveness of viral depuration.     

Selective impairments of memory functioning in unmedicated adults with Gilles de la Tourette's syndrome.

Different forms of memory linked to specific brain regions were assessed in unmedicated adults with Gilles de la Tourette's syndrome (TS) and in normal controls of equivalent age and educational attainment. TS patients were impaired on measures of strategic, working, and procedural memory associated with fronto-striatal function. In contrast, their performance was intact on measures of immediate, semantic, and declarative memory associated with temporal-diencephalic functioning. These findings are consistent with radiological evidence of fronto-striatal abnormalities in TS and provide convergent evidence that a fronto-striatal memory system mediates working memory in humans. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Word-identification priming for ignored and attended words

Three experiments examined contributions of study phase awareness of word identity to subsequent word-identification priming by manipulating visual attention to words at study. In Experiment 1, word-identification priming was reduced for ignored relative to attended words, even though ignored words were identified sufficiently to produce negative priming in the study phase. Word-identification priming was also reduced after color naming relative to emotional valence rating (Experiment 2) or word reading (Experiment 3), even though an effect of emotional valence upon color naming (Experiment 2) indicated that words were identified at study. Thus, word-identification priming was reduced even when word identification occurred at study. Word-identification priming may depend on awareness of word identity at the time of study.     

Dissociations between familiarity processes in explicit recognition and implicit perceptual memory.

Dual-process theories of recognition posit that a perceptual familiarity process contributes to both explicit recognition and implicit perceptual memory. This putative single familiarity process has been indexed by inclusion–exclusion, remember–know, and repetition priming measures. The present studies examined whether these measures identify a common familiarity process. Familiarity-based explicit recognition (as indexed by the inclusion–exclusion and the independence remember–know procedures) increased with conceptual processing. In contrast, implicit word-identification priming and familiarity-based word-stem completion (as indexed by inclusion–exclusion) increased with study–test perceptual similarity. These dissociations indicate that familiarity-based explicit recognition may be more sensitive to conceptual than to perceptual processing and is functionally distinct from the perceptual familiarity process mediating implicit perceptual memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)