Accelerated ageing of an EAF black slag by carbonation and percolation for long-term behaviour assessment.

The efficient reuse of industrial by-products, such as the electric arc furnace (EAF) black slag, is still hindered by concern over their long-term behaviour in outdoor environments. The aim of this study was to develop an accelerated ageing method to simulate the long-term natural carbonation of EAF slag exposed to the elements. The degree of carbonation achieved in a freshly produced slag after accelerated ageing and in a slag used on a fifteen-year-old unpaved road was very similar. The influence of particle size on accelerated carbonation was assessed, with it being concluded that the slag sample with a particle size bigger than 5-6 mm underwent slight carbonation over time when it was exposed to CO2. The accelerated ageing procedure based on percolating a previously carbonated water solution through the slag column allowed gradual leaching with simulated acid rain, as well as providing information about the gradual and total chemical release from the slag. Three classification groups were established according to the release rate of the determined elements. The joint use of the accelerated carbonation method and the percolation test is proposed as a useful tool for environmental risk assessment concerning the long-term air exposure of EAF black slag.

Testing for adaptive radiation: A new approach applied to Madagascar frogs.

Adaptive radiation is a key topic at the intersection of ecology and evolutionary biology. Yet the definition and identification of adaptive radiation both remain contentious. Here, we introduce a new approach for identifying adaptive radiations that combines key aspects of two widely used definitions. Our approach compares evolutionary rates in morphology, performance, and diversification between the candidate radiation and other clades. We then apply this approach to a putative adaptive radiation of frogs from Madagascar (Mantellidae). We present new data on morphology and performance from mantellid frogs, then compare rates of diversification and multivariate evolution of size, shape, and performance between mantellids and other frogs. We find that mantellids potentially pass our test for accelerated rates of evolution for shape, but not for size, performance, or diversification. Our results demonstrate that clades can have accelerated phenotypic evolution without rapid diversification (dubbed "adaptive non-radiation"). We also highlight general issues in testing for adaptive radiation, including taxon sampling and the problem of including another adaptive radiation among the comparison clades. Finally, we suggest that similar tests should be conducted on other putative adaptive radiations on Madagascar, comparing their evolutionary rates to those of related clades outside Madagascar. Based on our results, we speculate that older Madagascar clades may show evolutionary patterns more similar to those on a continent than an island.

Key plant species and detritivores drive diversity effects on instream leaf litter decomposition more than functional diversity: A microcosm study.

Anthropogenic impacts on freshwater ecosystems cause critical losses of biodiversity that can in turn impair key processes such as decomposition and nutrient cycling. Forest streams are mainly subsidized by terrestrial organic detritus, so their functioning and conservation status can be altered by changes in forest biodiversity and composition, particularly if these changes involve the replacement of functional groups or the loss of key species. We examined this issue using a microcosm experiment where we manipulated plant functional diversity (FD) (monocultures and low-FD and high-FD mixtures, resulting from different combinations of deciduous and evergreen Quercus species) and the presence of a key species (Alnus glutinosa), all in presence and absence of detritivores, and assessed effects on litter decomposition, nutrient cycling, and fungal and detritivore biomass. We found (i) positive diversity effects on detritivore-mediated decomposition, litter nutrient losses and detritivore biomass exclusively when A. glutinosa was present; and (ii) negative effects on the same processes when microbially mediated and on fungal biomass. Most positive trends could be explained by the higher litter palatability and litter trait variability obtained with the inclusion of alder leaves in the mixture. Our results support the hypothesis of a consistent slowing down of the decomposition process as a result of plant biodiversity loss, and hence effects on stream ecosystem functioning, especially when a key (N-fixing) species is lost; and underscore the importance of detritivores as drivers of plant diversity effects in the studied ecosystem processes.

Music supported therapy promotes motor plasticity in individuals with chronic stroke.

Novel rehabilitation interventions have improved motor recovery by induction of neural plasticity in individuals with stroke. Of these, Music-supported therapy (MST) is based on music training designed to restore motor deficits. Music training requires multimodal processing, involving the integration and co-operation of visual, motor, auditory, affective and cognitive systems. The main objective of this study was to assess, in a group of 20 individuals suffering from chronic stroke, the motor, cognitive, emotional and neuroplastic effects of MST. Using functional magnetic resonance imaging (fMRI) we observed a clear restitution of both activity and connectivity among auditory-motor regions of the affected hemisphere. Importantly, no differences were observed in this functional network in a healthy control group, ruling out possible confounds such as repeated imaging testing. Moreover, this increase in activity and connectivity between auditory and motor regions was accompanied by a functional improvement of the paretic hand. The present results confirm MST as a viable intervention to improve motor function in chronic stroke individuals.

Evaluating the impact of water supply strategies on p-xylene biodegradation performance in an organic media-based biofilter.

The influence of water irrigation on both the long-term and short-term performance of p-xylene biodegradation under several organic loading scenarios was investigated using an organic packing material composed of pelletised sawdust and pig manure. Process operation in a modular biofilter, using no external water supply other than the moisture from the saturated inlet air stream, showed poor p-xylene abatement efficiencies (≈33 ± 7%), while sustained irrigation every 25 days rendered a high removal efficiency (RE) for a critical loading rate of 120 g m(-3)h(-1). Periodic profiles of removal efficiency, temperature and moisture content were recorded throughout the biofilter column subsequent to each biofilter irrigation. Hence, higher p-xylene biodegradation rates were always initially recorded in the upper module, which resulted in a subsequent increase in temperature and a decrease in moisture content. This decrease in the moisture content in the upper module resulted in a higher removal rate in the middle module, while the moisture level in the lower module steadily increased as a result of water condensation. Based on these results, mass balance calculations performed using measured bed temperatures and relatively humidity values were successfully used to account for water balances in the biofilter over time. Finally, the absence of bed compaction after 550 days of continuous operation confirmed the suitability of this organic material for biofiltration processes.

Phenotypic changes in monocytes and alveolar macrophages in patients with acquired immunodeficiency syndrome (AIDS) and AIDS-related complex (ARC).

The expression of Class II histocompatibility antigens (HLA-DR and HLA-DQ), leukocyte function associated antigen (LFA-1) and complement receptor type 3 (CR3) on peripheral blood monocytes and alveolar macrophages (M phi) from patients with acquired immune deficiency syndrome (AIDS) and AIDS-related complex (ARC) and age-matched controls was studied. The percentage of HLA-DR+ monocytes from 4 AIDS patients and 12 ARC patients was 52.4 +/- 16.4% (p less than 0.05) and 50.2+21.2% (p less than 0.01) respectively (Controls, 75.4 +/- 12.6%). HLA-DQ expression in monocytes from one AIDS and two ARC patients was 31%, 39% and 18% respectively (in normal individuals, DQ was expressed by approximately 40% monocytes). HLA-DR and HLA-DQ expression on alveolar M phi from one AIDS patient and 2 ARC patients were also depressed. CR3 was expressed by 65.9 +/- 11.1% monocytes from normal controls. Patients with AIDS had a slightly, but significantly lower, proportion of CR3+ monocytes (43.9 +/- 15.9%, p less than 0.05) (in normal controls, CR3 monocytes were 65.9 +/- 11.1%). However, monocytes from ARC patients and alveolar M phi from one AIDS and 2 ARC patients expressed CR3 in a normal range. LFA-1 was significantly depressed in monocytes from both AIDS (45.7 +/- 1%, p less than 0.005) and ARC (57.5 +/- 10.9%, p less than 0.005) patients in comparison with controls (87.4 +/- 8.7%). Only alveolar M phi from one AIDS patient could be studied for LFA-1 antigen and this was into the normal range.(ABSTRACT TRUNCATED AT 250 WORDS)

Lipophilic derivatization of synthetic peptides belonging to NS3 and E2 proteins of GB virus-C (hepatitis G virus) and its effect on the interaction with model lipid membranes.

The synthesis by solid-phase methodologies of peptides belonging to structural and non-structural proteins of GB virus C as well as its N-alpha-acylation with myristate and palmitate fatty acids is described. To explore the peptide-lipid interactions we have used liposomes composed of dipalmitoylphosphatidylcholine as model membranes and complementary spectroscopic and calorimetric techniques. Our results show that structural and more clearly the structural lipophilic peptide sequences incorporated into lipid bilayers perturb the packing of lipids and affect their thermotropic properties, more than the non-structural selected sequence. However, the binding of the synthetic sequences to lipid membranes occurred without any restructuration of the peptides.

Intravenous DSA of extracranial carotid lesions: comparison with other techniques and specimens.

Intravenous digital subtraction arteriography (DSA) was performed in 306 patients with suspected ischemic cerebrovascular disease. Forty-eight carotid endarterectomies were performed in 43 of these patients. The percentage stenosis as determined on the intravenous DSA examination concurred (+/- 10%) with the surgical findings in 83.3%. There were 12.5% undercalls (false-negatives) and 4.3% overcalls (false-positives). Of the false-negative and false-positive examinations only three would have affected the clinical management of the patient, yielding an overall sensitivity of 93.7%. Nine surgical lesions had both intravenous DSA and conventional arteriography. Intravenous DSA was correct in six and arteriography in seven of these lesions. There were four surgically confirmed ulcerations. Two were evaluated by intravenous DSA alone. Two had intravenous DSA and arteriography. The latter showed both ulcers; the former, only one. Thirty-seven surgical lesions had both intravenous DSA and high-resolution real-time sonographic imaging. Sonography agreed in 67.5% and intravenous DSA in 83.7% of these lesions. When an abnormal supraorbital Doppler or an abnormal oculopneumoplethysmography/Gee examination is added to the sonographic examination, an overall sensitivity of 93% was obtained in detecting a surgical lesion (stenosis greater than 50%).

Spectroscopic analysis of the interaction of a peptide sequence of Hepatitis G virus with bilayers.

Merocyanine 540 (MC540) has been used as external probe to determine the interaction of the peptide sequence 125-139 corresponding to the E2 protein of Hepatitis G virus, with lipid bilayers. The probe was incorporated into large unilamellar vesicles (LUVs) or small unilamellar vesicles (SUVs) of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC). When incorporated into bilayers, MC540 shows two absorption maxima corresponding to the monomer (570 nm) and dimer (530 nm) form of the probe. Changes in the probe microenvironment are reflected by a modification in the position and/or intensity of these maxima. Addition of increasing amounts of peptide resulted in a slight decrease of the ratio A570/A530 thus indicating a change in MC540 partition into the membrane, going from a hydrophobic to a more hydrophilic environment. This effect was concomitant with an increase in dimer formation as stated from the values of the apparent dimerization constant (K(app)) obtained. Fluorescence spectra as well as steady state anisotropy measurements were in agreement with the above results indicating that the peptide was able to relocate the probe and displacing MC540 from its initial location into the bilayer. Results with SUVs or LUVs were similar for what curvature does not seem to play any role on peptide activity. These results reflect the ability of peptide to interact with biomimetic membranes in the lipid head group region.

Fluorescence analysis of the interaction of two peptide sequences of hepatitis GB virus C with liposomes.

The physicochemical characterization of the peptide sequences E2 (39-53) and E2 (32-59) corresponding to the structural protein E2 of the GB virus C was done by studying their interaction with model membranes. The peptides showed surface activity concentration dependent when injected beneath a buffered solution. This tendency to accumulate into the air/water interface suggested a potential ability of these peptides to interact with bilayers. For that reason, Small Unilamellar Liposomes (SUVs) of 1,2-dimyiristoyl-sn-Glycero-3-Phosphocholine (DMPC) or 1,2-dimyiristoyl-sn-Glycero-3-[Phospho-rac-(1-glycerol)] (DMPG) were chosen as a mimetic membranes. A series of fluorescence experiments based on tryptophan peptide fluorescence or with fluorescence labeled SUVs, were done to cover different aspects of peptide interaction with bilayers. Steady state fluorescence anisotropy studies with N-(7-nitro-2-1,3-benzoxadiazol-4-yl) dioleoylphosphatidylethanolamine (NBD-PE) or 1-[4-(trimethylammonium) phenyl]-6-phenyl-1,3,5-hexatriene (TMA-DPH) labeled SUVs indicated that only the long peptide was able to change the lipid microenvironment of DMPG vesicles by slightly increasing the rigidity of the bilayer both above and under the lipid main transition temperature. These results were concordant with the slight blue shift of the maximum tryptophan wavelength emission after E2 (32-53) peptide incubation with DMPG vesicles. Our data provide useful information for the design of synthetic immunopeptides that can be incorporated into a liposomal system with a potential to promote a direct delivery of the membrane-incorporated immunogen to the immunocompetent cells, thus increasing the immuno response from the host.