Working memory functioning in medicated Parkinson's disease patients and the effect of withdrawal of dopaminergic medication.

Cognitive impairments in Parkinson's disease (PD) could be explained by a central executive (CE) deficit in A. D. Baddeley's (1986) working memory model. To test this hypothesis, verbal, spatial, and double span tasks were given to 12 medicated PD patients and control participants, with varying recall delays. The double span task was assigned to explore the coordinating and integrating function of the CE, and lengthening the recall delay was expected to implicate more attentional resources. PD patients had lower spans relative to controls in all tasks. However, the more specific implication of the CE was difficult to prove. One reason could be that PD patients were on dopaminergic treatment when tested. To control this effect, 12 PD patients on and off medication were studied in a second experiment using the same tasks. PD patients off medication had lower spans only in the double task; this result underlines the role of dopamine on working memory processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of decontamination on the microbial load,the sensory quality and the nutrient retention of ready-to-eat white cabbage

The effect of different decontamination treatments such as washing with sodium hypochlorite (20 and 200 mg/L), peroxyacetic acid (80 and 250 mg/L), neutral electrolysed oxidising water (4.9 and 31.7 mg/L free chlorine) and contact with 1.55 mg/L chlorine dioxide gas on the microbial and sensory quality, and the nutrient content of fresh-cut white cabbage was studied. Only rinsing with 200 mg/L sodium hypochlorite, peroxyacetic acid or contact with gaseous chlorine dioxide resulted in significantly higher reductions of the total plate count (1.5–2.5 log cfu/g) than the ones achieved by washing with tap water (0.5 log cfu/g). However, those treatments giving the best results from a microbial point of view induced significant changes in the sensory quality. Regarding the effects on nutrient content, the mechanical effects caused by water washing already reduced the vitamin C content by 16–29%. Contrary to washing with neutral electrolysed oxidising water and contact with chlorine dioxide gas, a supplementary decrease of the vitamin C content ranging between 9 and 28% was observed, when peroxyacetic acid or 200 mg/L sodium hypochlorite were used. After the use of peroxyacetic acid or gaseous chlorine dioxide, the phenol content also showed a decreasing trend, although not statistically significant. Apart from the effect of washing with water, the lipophilic nutrients were well retained after a decontamination step except for the α-tocopherol content, when peroxyacetic acid was used (−43 to 56%), and for the all-trans-β-carotene content (−8%) of cabbage in contact with gaseous chlorine dioxide. Because of its potential to reduce the initial microbial load without negative effects on the sensory quality, in combination with its limited effects on nutrient content, a treatment with 80 mg/L peroxyacetic acid is preferable to decontaminate fresh-cut white cabbage.     

Relationships between sensory and physicochemical measurements in meat of rabbit from three different breeding systems using canonical correlation analysis

Meat from rabbits reared either according to a standard (STAND) or a high quality norm (LABEL) or a low growth breeding (RUSSE) system were submitted to a sensory evaluation and to a large set of physicochemical measurements (weight of retail cuts, colour parameters, ultimate pH, femur flexure test, Warner-Bratzler shear test, water holding capacities and cooking losses). STAND rabbit meat exhibited the most juicy meat in back and in leg (p<0.01). Leg tenderness significantly decreased (p<0.001) in the rank order STAND>LABEL>RUSSE. Canonical correlation analysis showed strong correlations between physicochemical and sensory variables (R(2)=0.73 and 0.68 between the two first pairs of canonical variates). Especially, sensory tenderness and WB shear test variables assessed on raw longissimus muscle (LL) were correlated. Fibrous attribute in back was correlated with cooking loss in LL. When analysed separately only RUSSE rabbits exhibited the same relations between variables as those calculated in whole dataset.     

Passion for an activity and quality of interpersonal relationships: The mediating role of emotions.

Our purpose in this research was to investigate the role of passion (Vallerand et al., 2003) for a given activity in the quality of interpersonal relationships experienced within the context of that activity in 4 studies. Study 1 demonstrated that a harmonious passion was positively associated with the quality of interpersonal relationships within the context of the passionate activity, whereas an obsessive passion was unrelated to it. Furthermore, in line with the broaden-and-build theory (Fredrickson, 2001), results also showed that positive emotions experienced at work fully mediated the relation between harmonious passion and quality of interpersonal relationships. Obsessive passion was not associated with positive emotions. Study 2 replicated the results from Study 1 while controlling for trait extraversion. Also, in Study 2, we examined the negative mediating role of negative emotions between obsessive passion and quality of interpersonal relationships. Finally, Studies 3 and 4 replicated the results of Study 2 with prospective designs and with objective ratings of interpersonal relationships quality. Implications for the dualistic model of passion and the broaden-and-build theory are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Multi-scale Cryptosporidium/sand interactions in water treatment

Owing to its widespread occurrence in drinking water supplies and its significant resistance to environmental stresses, Cryptosporidium parvum is regarded as one of the most important waterborne microbial parasites. Accordingly, a substantial research effort has been aimed at elucidating the physical, chemical and biological factors controlling the transport and removal of Cryptosporidium oocysts in natural subsurface environments and drinking water treatment facilities. In this review, a multi-scale approach is taken to discuss the current state-of-knowledge on Cryptosporidium-sand interactions at a nano-scale, bench-scale and field-scale relevant to water treatment operations. Studies conducted at the nano-scale and bench-scale illustrate how techniques based on the principles of colloid and surface chemistry are providing new insights about oocyst-sand interactions during transport of Cryptosporidium oocysts in granular porous media. Specifically, atomic force microscopy and impinging jet experiments reveal the importance of oocyst surface biomolecules in controlling Cryptosporidium/sand interactions by a mechanism of steric hindrance. Traditional bench-scale column transport studies conducted over a broad range of experimental conditions highlight the role of physicochemical filtration and physical straining in the removal of oocysts from the pore fluid. Such experiments have also been used to evaluate the influence of biofilms formed on grain surfaces and the presence of natural organic matter on oocyst-sand interactions. Whilst filtration studies conducted at the plant-scale have been useful for evaluating the effectiveness of various materials as surrogates for Cryptosporidium oocysts, at this macro-scale, little could be learnt about the fundamental mechanisms controlling oocyst-sand interactions. This review of the literature on Cryptosporidium-sand interactions at different length scales points to the importance of combining studies at the plant-scale with well-controlled investigations conducted at the nano- and bench-scales. Furthermore, because oocyst surface properties play an important role in controlling the extent of interaction with sand surfaces, a thorough discussion of Cryptosporidium oocyst characteristics and electrical properties is presented.     

Spin Diffusion Measurements in Spin-Polarised Liquid 3He-4He Mixtures

We report on investigations of spin diffusion in isotopic helium liquid mixtures using a multi-echo technique in applied magnetic field gradients. Samples (up to 1 cm ³ in volume) are obtained by liquefaction of optically polarised gas. NMR measurements are performed at saturated vapour pressure in a low magnetic field (2.2 mT). Signal-to-noise ratios stay high down to ³ He concentrations of order a few parts per thousand at 1K for instance. We demonstrate that the experimental accuracy of spin diffusion measurements is substantially improved using optically polarised mixtures. We have observed that the dynamics of the precession of the transverse magnetisation can be altered due to large dipolar fields at high magnetisation densities. Effects on spin-echo signals and implications for the extension of spin diffusion measurements with our technique are discussed.     

Highly porous PEM fuel cell cathodes based on low density carbon aerogels as Pt-support: Experimental study of the mass-transport losses

Carbon aerogels exhibiting high porous volumes and high surface areas, differentiated by their pore-size distributions were used as Pt-supports in the cathode catalytic layer of H₂/air-fed PEM fuel cell. The cathodes were tested as 50 cm² membrane electrode assemblies (MEAs). The porous structure of the synthesized catalytic layers was impacted by the nanostructure of the Pt-doped carbon aerogels (Pt/CAs). In this paper thus we present an experimental study aiming at establishing links between the porous structure of the cathode catalytic layers and the MEAs performances. For that purpose, the polarization curves of the MEAs were decomposed in 3 contributions: the kinetic loss, the ohmic loss and the mass-transport loss. We showed that the MEAs made with the different carbon aerogels had similar kinetic activities (low current density performance) but very different mass-transport voltage losses. It was found that the higher the pore-size of the initial carbon aerogel, the higher the mass-transport voltage losses. Supported by our porosimetry (N₂-adsorption and Hg-porosimetry) measurement, we interpret this apparent contradiction as the consequence of the more important Nafion penetration into the carbon aeorogel with larger pore-size. Indeed, the catalytic layers made from the larger pore-size carbon aerogel had lower porosities. We thus show in this work that carbon aerogels are materials with tailored nanostructured structure which can be used as model materials for experimentally testing the optimization of the PEM fuel cell catalytic layers.