Classical conditioning in patients with Alzheimer's disease: A multiday study.

Previous studies demonstrated that patients with Alzheimer's disease (AD) do not acquire the classically conditioned eyeblink response. These studies, however, were only tested over a single conditioning session and, hence, raise the question of whether AD patients are capable of acquiring the response if sufficient training is given. This question may be of some importance because whether AD patients can ultimately acquire the response has implications for the underlying neurobiological deficit in disrupted conditioning in AD. This study tested AD patients and age-matched controls over 4 days. As in previous studies, AD patients performed significantly worse than controls on Day 1, but by Day 4, they were not significantly different from controls. Subsequent testing indicated that these effects were not due to nonassociative variables such as changes in sensitivity to stimuli or disruption of the motor response. Also, it was reported that neither AD patients nor controls showed any evidence of acquisition in an explicitly unpaired paradigm, suggesting that neither pseudoconditioning nor sensitization is contributory. Data are discussed in terms of the possible role of the hippocampus in mediating conditioning deficits in AD patients. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Rheological,mechanical, thermal,and morphological properties of polypropylene/ethylene‐octene copolymer blends

Rheological and morphological studies were performed on polymer blends of ethylene‐octene copolymer [polyethylene elastomer (PEE)] and polypropylene (PP). The viscosities of PEE, PP, and PEE/PP blends were analyzed using an Instron capillary rheometer and a Rheometrics Dynamic Stress Rheometer, SR 200. A non‐Newtonian flow behavior was observed in all samples in the shear rate range from 27 to 2700 s⁻¹, whereas at shear rates in the range from 0.01 to 0.04 s⁻¹, a Newtonian flow behavior was verified. The scanning electron micrographs showed that dual‐phase continuity may occur between 50 and 60 (wt %) of PEE. This result is consistent with the Sperling's model. The mechanical analysis showed that PEE/PP, with 5 wt % of PEE, presented an increase on the mechanical properties and as the PEE content increased, a negative deviation in relation to an empirical equation was observed. Thermal analysis showed that there were no change in the crystallization behavior of the matrix when different elastomer contents were added. Dynamic mechanical thermal analysis showed that samples with low PEE contents presented only one peak, indicating a certain degree of miscibility between the components of these blends. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 692–704, 2000     

Hydrolysis of soya milk oligosaccharides by Bifidobacterium longum CRL 849

 The reduction of soya milk oligosaccharides by Bifidobacterium longum CRL 849 was studied. The utilization of stachyose was concomitant with the use of sucrose. Maximum hydrolysis of stachyose (49.3%) occurred during the first 7 h of incubation at 37  °C, while a 79.3% decrease in the concentration of sucrose was observed after 9 h. No raffinose was detected after hydrolysis of the stachyose. Cell population decreased after 8 h of incubation because of the low pH attained (pH 4.7). l(+)-Lactate concentration was higher than acetate (molar ratio 6.7 : 1) at 6 h followed by a slow increase in acetate formation. Ethanol was detected in small amounts at the end of the incubation time (24 h). Received: 29 December 1997     

An Online Measure of Thought Suppression.

An online thought-suppression paradigm was developed to test predictions of ironic process theory. Participants concentrated on or suppressed a particular semantic category. Semantic activation was indexed by the latency to name words from the category. In Experiments 1 and 2, an analog intrusion was introduced while participants were trying to suppress the information. Results consistent with ironic process theory were observed using words with polar opposites in Experiment 1 and words without polar opposites in Experiment 2. To determine whether these effects were dependent on the analog intrusion, Experiment 3 replicated Experiment 1 without the intrusion. Concentration generated semantic activation, but suppression exacerbated this activation. The data imply that hyperaccessibility results from efforts to suppress, whereas the processes of thought suppression identified by ironic process theory require the presence of material inconsistent with a desired cognitive state. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Methadone maintenance improves cognitive performance after two months of treatment.

Methadone maintenance (MM) has received little scientific attention regarding neurocognitive effects. The present study examined cognitive function in 17 opiate-dependent subjects at baseline and after 2 months of MM treatment. Subjects demonstrated significant improvements from baseline on measures of verbal learning and memory, visuospatial memory, and psychomotor speed and reduced frequency of drug use (Addiction Severity Index) relative to baseline, although the total percentage of urine samples positive for additional illicit substances was slightly increased. No effect of illicit drug use was observed when the sample was stratified by urine toxicology results, suggesting that improvements in cognition were not associated with additional illicit drug use. Results suggest that opiate-dependent subjects exhibit significant improvement in cognitive function after MM treatment. Future investigations are needed to confirm these findings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Extraction of heavy metal ions from leachate of cement-based stabilized waste using purpurin functionalized resin

A new chelating resin was synthesized by functionalization of a polymer support, Amberlite XAD-2 with purpurin through an azo linkage (NN). The products were characterized by scanning electron microscopy, elemental analysis, Fourier transform infrared spectroscopy and thermogravimetric analysis. The optimum conditions for the extraction of Cd(II), Cr(III) and Pb(II) in two matrices; leachate from cement-based material and de-ionized water, were studied by batch and column methods. The determination of the metal ions was carried out by flame atomic absorption spectrometry. The optimum pH for the extraction of all metal ions in both matrices were at 4.0. Their sorption equilibrium was reached within 1h. The sorbed Cd(II) and Pb(II) were eluted by 1% HNO3 within 10 min with the desorption recovery of >90%. The elution of Cr(III) by 3% H2O2 in 0.1 M NaOH was achieved within 30 min with the desorption recovery of >80%. The sorption capacity of Cd(II), Cr(III) and Pb(II) onto the resin was 75.0, 68.2, 82.7 micromol g(-1) resin in DI water and 54.1, 46.5 and 55.7 micromol g(-1) resin in leachate, respectively. The extraction efficiency in the column method can be improved using the recirculation system. This new method gave a good accuracy in batch system with the recovery of 86.5 and 89.9% for Cd(II) and Pb(II) and R.S.D. less than 2.3% (n=14).     

Prenatal exposure to mercury in a prospective mother-infant cohort study in a Mediterranean area, Valencia, Spain

BACKGROUND: Mercury (Hg) is a ubiquitous pollutant that negatively affects fetal and child neurodevelopment at accidental high-dose exposure. Some studies indicate that Mediterranean populations could be at risk of prenatal exposure to mercury through fish consumption. OBJECTIVES: To assess the prenatal exposure to total mercury (T-Hg), both inorganic and organic, in newborns by analyzing the T-Hg concentration in cord blood, and to evaluate the role of maternal fish consumption in this exposure. METHODS: In the context of a multi-center project (INMA project), a prospective birth cohort was set up in Valencia, Spain, from 2005 to 2006. A total of 253 newborns were included in this study. We compared cord blood T-Hg concentration by levels of fish intake assessed by a food frequency questionnaire completed at 28-32 weeks of gestation. Maternal covariates were obtained through a questionnaire. RESULTS: The geometric mean of T-Hg at birth was 9.9 microg/L (95% CI: 9.0, 10.8). Seventy five percent of cord blood samples were above the estimated level assumed to be without appreciable harm (5.8 microg/L). Women who consumed a portion of large oily fish, lean fish, or mixed fried fish two or more times per week had mean cord blood levels 1.6, 1.4 and 1.3 times higher, respectively, than those who rarely or never consumed fish. Other factors such as the mother's age, country of origin, smoking and season of delivery were also significantly and independently associated with cord blood T-Hg concentrations. CONCLUSIONS: Newborns from a Mediterranean area presented elevated levels of T-Hg in cord blood. Higher concentrations of T-Hg were related to maternal fish intake, particularly in the case of large oily fish species.     

Influence of a salt marsh plant (Halimione portulacoides) on the concentrations and potential mobility of metals in sediments

Influence of Halimione portulacoides, commonly found in temperate salt marshes, on sediment metal contents, speciation and potential mobility in case of sediment re-suspension was evaluated. Both colonized and non-colonized sediments were studied for total Cd, Cu, Pb and Zn contents and metal fraction exchangeable to water collected in situ. Sediment elutriates, prepared with water collected from each site, were used to simulate a sediment re-suspension phenomenon. As the characteristics and degree of contamination of sediments may influence system behaviour, salt marshes of two Portuguese estuaries, Cavado (NW coast) and Sado (SW coast), were studied. Cu, Pb and Zn contents higher than ERL (quality guideline, effect range-low) were observed, indicating potential risks for living organisms. Strong Cu-complexing organic ligands, also determined in both water and elutriates, were higher in rhizosediment elutriates, at concentrations similar, or even higher, to those of Cu. Such ligands condition metals speciation in the water column and probably also metal bioavailability. From rhizosediment significant amounts of Cu and Zn were transferred to the aqueous phase, concentrations 2-8 times higher than concentrations present in water. In contrast, elutriates of non-colonized sediment removed metals from water, Cu and Zn levels in elutriates being 2-6 times lower than initial ones. Cd and Pb levels in water and elutriates were not measurable in most cases. Results clearly indicate that metals potential solubility in the rhizosphere of plants was markedly higher than that in the surrounding sediment. The obtained results indicated that H. portulacoides presence (and probably other salt marsh plants) may cause a marked increase in metals concentrations in dissolved phase (pore water or even water column if rhizosediment is re-suspended). As salt marsh plants may be abundant in temperate and subtropical estuaries and costal lagoons, this phenomenon should not be disregard in future studies towards the sustainable management of such environments.     

Diffusion coefficients and electrical conductivities for calcium chloride aqueous solutions at 298.15 K and 310.15 K

Experimental values for mutual diffusion coefficients (interdiffusion coefficients) for CaCl₂ aqueous solutions at 298.15 K and 310.15 K, not available in the literature, were experimentally determined between 0.005 mol dm^?3 and 0.1 mol dm^?3. The measurements were performed by using a conductimetric open-ended capillary cell. Values at infinitesimal concentration, D⁰, were also obtained. These data were analysed using the Onsager–Fuoss and Gordon models. In addition, molar conductance data were measured at 310.15 K for CaCl₂ aqueous solutions at the same concentration range and the value at infinitesimal concentration determined. Afterwards, it was split into the ionic limiting values. By replacing them into the Nernst equation, diffusion coefficients at infinitesimal concentration were derived (1.335 × 10^?9 m² s^?1 and 1.659 × 10^?9 m² s^?1) at both temperatures (298.15 K and 310.15 K, respectively). They agree well with the extrapolated experimental ones (1.312 × 10^?9 m² s^?1 and 1.613 × 10^?9 m² s^?1).