Non‐Conventional Electrochemical Techniques for Assembly of Electrodes on Glassy Carbon‐Like PPF Materials and Their Use in a Glucose Microfluidic Fuel‐Cell

This paper addresses the electrochemical growth of PtAg and Au nanoparticles on pyrolyzed photoresist films (PPFs). The PtAg/PPF electrode was evaluated toward oxygen reduction reaction (ORR) in the absence and presence of glucose; meanwhile the electrocatalytic activity of Au/PPF was investigated for the glucose electrooxidation reaction (GOR) in 0.3 M KOH in the absence and presence of air as an oxygen source. The results obtained using the electrochemical studies showed that the PtAg/PPF electrode exhibited tolerance toward the ORR in the presence of low glucose concentrations. Moreover, Au/PPF showed good affinity toward glucose oxidation at high concentrations (50 and 100 mM) in the presence of oxygen instead further oxidations of glucose by‐products. Both electrocatalysts were evaluated as the cathode (PtAg/PPF) and the anode (Au/PPF) in a glucose microfluidic fuel cell (G‐μFC) constructed using a UV‐lithography technique and several sheets of different polymeric materials. The G‐μFC was tested using 100 mM glucose with 0.3 M KOH as electrolyte in the absence of an external source of nitrogen or oxygen as the fuel at zero flow rate; this cell reached a maximum power density of 0.085 mW cm⁻² using a low Pt loading (approximately 20% of weight percentage) mixed with non‐noble materials, such as Ag.     

EFFECT OF NATIVE AND LYOPHILIZED KEFIR GRAINS ON SENSORY AND PHYSICAL ATTRIBUTES OF WHEAT BREAD

Native and lyophilized kefir grains were added directly to bread dough or as a starter in sourdough. Because of inadequate leavening activity of kefir, yeast‐leavened breads were prepared. Kefir addition influenced the quality attributes and the shelf life of wheat bread. The pH of bread containing kefir decreased as compared to that in the control bread. The acidity of bread with kefir increased as compared to that in the control bread. An addition of kefir grains, regardless of the form, lowered the bread volume and increased the mold‐free shelf life from 4 (control) to 5–7 days. The addition of kefir grains in bread dough contributed to a milder taste, a more delicate yogurt‐like or dairy aroma. The breads made with sourdoughs containing native or lyophilized kefir grains scored higher for crumb quality number than breads made by directly adding kefir grains.     

Aspergillus kawachii produces an acidic pectin releasing enzyme activity

A pectin-releasing (protopectinase, PPase) activity was found in a culture filtrate of Aspergillus kawachii IFO 4308. PPase activity was highest in the pH range of 2.0-2.5 and it was highly stable at 50 degrees C (85% of residual activity was found after a 10-h incubation in citrate-phosphate buffer, pH 3.0). Among other different enzyme activities, which are usually involved in plant cell-wall degradation, only polygalacturonase activity was detected. This result suggests that the PPase activity could correspond to a particular kind of polygalacturonase. Pectin extraction from lemon peels carried out at 50 degrees C for 2 h (pH 3.5) gave yields of ethanol-precipitated pectin equivalent to 17.4% of the initial total solids contained in the peels. Thus, this enzyme activity would allow carrying out a pectin extraction process at lower reaction pHs and higher temperatures in comparison with similar reports using other PPases. These properties seem to be very interesting from the practical point of view.     

The hot rectus abdominis muscle sign

We report a 2.5-year-old child who presented with an acute abdomen caused by the perforation of a sewing pin through her appendix that had started to penetrate the wall of the bladder.     

A longitudinal study of the social and academic competence of economically disadvantaged bilingual preschool children.

This longitudinal study was conducted to gain understanding of the social–emotional and academic development of economically disadvantaged bilingual preschool children. In Study 1, the authors combined cognitive, psychosocial, and cultural-linguistic factors to determine profiles of social competence as measured by peer play. A person-centered analysis of 207 Hispanic American preschoolers (ages 4 and 5 years) yielded 6 distinct profiles, 2 of which were socially competent and 1 of which was vulnerable. Findings revealed profile differences in social competence and a significant relationship between bilingualism and social–emotional development. In Study 2, the authors determined which profiles were associated with later academic achievement and growth of English proficiency. Findings indicated a significant relationship of early social–emotional development to later academic success and English acquisition, highlighting the role of bilingualism. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Improvement of as-milled properties of mechanically alloyed LaNi5 and application to hydrogen thermal compression

LaNi₅ was obtained from raw materials by low energy mechanical alloying. Hydriding properties of as-milled intermetallic were improved by annealing. Pressure-composition isotherms showed flat plateaus when annealing temperature was 600 °C, this value is at least 300 °C lower than the synthesis and annealing temperature of standard equilibrium methods. This low energy mechanical alloying - low temperature annealing procedure reduces the number of intermediate stages needed to scale up the fabrication of the intermetallic. After cycling this material in hydrogen, its hydriding properties were studied in the 25-90 °C range. From these results, we propose a one-stage hydrogen thermal compression scheme working between 25 °C (absorption) and 90 °C (desorption) with a compression ratio of 2.5 and a useful capacity of 1.0 mass %.     

Properties of the regulatory subunit of cAMP-dependent protein kinase type II from human brain

The regulatory subunit type II (RII) of cAMP-dependent protein kinase purified from human brain was represented by two proteins with apparent molecular masses of 51-52 kD and 54 kD. Dephosphorylation of human RII containing 3 mol phosphate/mol protein did not change the electrophoretic pattern. One-dimensional peptide mapping of 51-52 kD and 54 kD proteins after digestion with St. aureus V8 protease evidenced to their being distinct proteins. The data obtained permit to assume that human RII of neural type is represented by two isoforms.     

The theta rhythm of the infant EEG and the development of the mechanisms of voluntary control of attention in the 2nd half of the first year of life

The neurophysiological basis of attention control was studied in infants at the second half-year of life, i.e. in the period when the capability for voluntary control over behavior fundamentally improves. EEG was recorded in 60 infants aed 8-11 months in three experimental conditions: 1) attention to an object in the visual field (externally controlled attention, or the baseline state), 2) anticipation of a person in the peek-a-boo game (internally controlled attention), 3) attention to the reappeared person in the peek-a-boo game (control condition). The spectral analysis of the EEG data revealed a sharp increase in the EEG theta (3.6-6.0 Hz) during internally controlled attention as compared to the baseline and control conditions. The theta1 (3.6-4.8 Hz) increase was maximal in the frontal derivations. The reactivity of the frontal theta1 during internally controlled attention discriminated infants with different abilities to maintain this type of attention. The reactivity of the theta2 (5.2-6.0 Hz) was maximal in the right temporal derivation (T6) and did not depend on stability of the anticipatory attention. The findings point to different functional significance of the theta1 and theta2 rhythms in infants. It is suggested that synchronization of the frontal theta1 rhythm in infants reflects the activity of the anterior attention system which realizes the executive attention control. The ability to maintain anticipatory attention increased with age, whereas the frontal theta1 synchronization decreased and totally disappeared at the age of 11 months. At the age of 8 months there was a positive correlation between the frontal theta1 synchronization and behavioral index of stability of the internally controlled attention. On the contrary, this correlation was negative at the age of 9 and 10 months. It is suggested that the age-dependent dynamics of the relationship between the frontal theta1 reactivity and attention reflects a leap in maturation of the anterior attention system resulting in its more economic and efficient functioning.