Effect of maternal high histidine levels on activity and maze retention in the rat.

4 groups of pregnant albino rats were maintained on either a histidine-high diet, or received periodic injections of C-nitromethane, or they received both treatments throughout gestation. Later, the offspring were tested in an open field for activity in a maze-learning task and retested for the retention of the maze habit. Results show that both nitromethane injections and histidine-high diets resulted in impaired performance. On the open field test, the experimental Ss were more active, and on initial learning of the maze pattern they demonstrated a learning deficit. However, when retested 7 and 30 days later, they showed no deficit in retention of the maze habit. In addition, an analysis of covariance indicated that the hyperactivity and learning deficit were independent characteristics of maternal hyperhistidinemia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of interpersonal group composition on the problem-solving behavior of middle managers.

Examined the effects of compatible and incompatible group composition on the problem-solving behavior of middle managers who had spent time together in work-management conferences. 22 groups (n = 10-12 per group) were administered the Fundamental Interpersonal Relationship Orientation-Behavior at the start of their conference. The Lego Man, a problem-solving exercise, was administered the 2nd day. Groups that were more compatible on the interpersonal dimensions of control and affection completed the task more rapidly than more incompatible groups. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Deficient motor synchrony in schizophrenia.

Introduced a laboratory measure of motor function, synchronization of tapping with an auditory stimulus, as an index of motor disorganization in schizophrenia. It was hypothesized that (a) schizophrenics' performance on this task would be distinguishable from that of controls and would reflect a relative inability to take advantage of stimulus predictability, independent of task difficulty; (b) clinical measures of disturbed motor behavior would be associated with poorer synchronization; and (c) synchronization performance would be associated with clinical ratings of formal thought disorder and type-token ratio assessment of disorganization in spoken language. 16 schizophrenic, 8 affective, and 8 normal controls (18–48 yrs) were studied. The schizophrenics showed a specific pattern of disrupted synchrony not consistent with explanations based on S motivation, task difficulty, motor dexterity, a general psychosis factor, drug effects, or tapping speed ability. Deficient motor performance was associated with clinical evidence of abnormal movement and disturbed thinking and with the type-token ratio. (44 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Escherichia coli O157:H7 Biofilm Formation on Romaine Lettuce and Spinach Leaf Surfaces Reduces Efficacy of Irradiation and Sodium Hypochlorite Washes

Abstract: Escherichia coli O157:H7 contamination of leafy green vegetables is an ongoing concern for consumers. Biofilm-associated pathogens are relatively resistant to chemical treatments, but little is known about their response to irradiation. Leaves of Romaine lettuce and baby spinach were dip inoculated with E. coli O157:H7 and stored at 4 °C for various times (0, 24, 48, 72 h) to allow biofilms to form. After each time, leaves were treated with either a 3-min wash with a sodium hypochlorite solution (0, 300, or 600 ppm) or increasing doses of irradiation (0, 0.25, 0.5, 0.75, or 1 kGy). Viable bacteria were recovered and enumerated. Chlorine washes were generally only moderately effective, and resulted in maximal reductions of 1.3 log CFU/g for baby spinach and 1.8 log CFU/g for Romaine. Increasing time in storage prior to chemical treatment had no effect on spinach, and had an inconsistent effect on 600 ppm applied to Romaine. Allowing time for formation of biofilm-like aggregations reduced the efficacy of irradiation. D₁₀ values (the dose required for a 1 log reduction) significantly increased with increasing storage time, up to 48 h postinoculation. From 0 h of storage, D₁₀ increased from 0.19 kGy to a maximum of 0.40 to 0.43 kGy for Romaine and 0.52 to 0.54 kGy for spinach. SEM showed developing biofilms on both types of leaves during storage. Bacterial colonization of the stomata was extensive on spinach, but not on Romaine. These results indicate that the protection of bacteria on the leaf surface by biofilm formation and stomatal colonization can reduce the antimicrobial efficacy of irradiation on leafy green vegetables. Practical Application: Before incorporating irradiation into the overall GMP/GHP chain, a packer or processor of leafy green vegetables must determine at what stage of processing and shipping the irradiation should take place. As a penetrating process, irradiation is best applied as a postpackaging intervention. Time in refrigerated storage between packaging and processing may alter the antimicrobial efficacy of irradiation. Irradiation on a commercial scale should include efforts to minimize the time delay between final packaging and irradiation of leafy vegetables.     

Effect of organic chelates on the performance of hybrid sol–gel coated AA 2024-T3 aluminium alloys

Sol–gels are organic–inorganic polymers formed by hydrolysis/condensation reactions of alkoxide precursors, primarily silanes, which have found applications as electronic, optical and protective coatings. These coatings possess important characteristics such as chemical stability, physical strength and scratch resistance. Further performance improvement is achieved through the incorporation of zirconium and titanium based nanoparticles, also formed through the sol–gel process. However due to the inherent difference in the reactivity of the precursors, the hydrolysis of each precursor must be carried out separately before being combined for final condensation. Zirconium precursors are commonly chelated using acetic acids, prior to hydrolysis, to lower the hydrolysis rate.In this body of work various ligands such as organic acids, acetyl acetone (AcAc) and 2,2′-bipyridine (Bipy) were used to control the zirconium hydrolysis reaction and form nanoparticles within the silane sol matrix.Nanoparticle modified coatings formed from the silane sol on AA 2024-T3 aluminium were characterised spectroscopically, electrochemically and calorimetrically to evaluate the potential effect of the different chelates on the final film properties while neutral salt spray tests were performed to study their anti-corrosion performance. Results indicate that the acid ligand modified coatings provided the best performance followed by AcAc, while Bipy was the poorest. In all cases the zirconium nanoparticle improved the protective properties of the sol–gel coating.     

Dynamic Microcapsules with Rapid and Reversible Permeability Switching

Dynamic microcapsules are reported that exhibit shell membranes with fast and reversible changes in permeability in response to external stimuli. A hydrophobic anhydride monomer is employed in the thiol–ene polymerization as a disguised precursor for the acid‐containing shells; this enables the direct encapsulation of aqueous cargo in the liquid core using microfluidic fabrication of water‐in‐oil‐in‐water double emulsion drops. The poly(anhydride) shells hydrolyze in their aqueous environment without further chemical treatment, yielding cross‐linked poly(acid) microcapsules that exhibit trigger‐responsive and reversible property changes. The microcapsule shell can actively be switched numerous times between impermeable and permeable due to the exceptional mechanical properties of the thiol–ene network that prevent rupture or failure of the membrane, allowing it to withstand the mechanical stresses imposed on the capsule during the dynamic property changes. The permeability and molecular weight cutoff of the microcapsules can dynamically be controlled with triggers such as pH and ionic environment. The reversibly triggered changes in permeability of the shell exhibit a response time of seconds, enabling actively adjustable release profiles, as well as on‐demand capture, trapping, and release of cargo molecules with molecular selectivity and fast on‐off rates.