Rate-limiting steps of tyrosinase-modified electrodes for the detection of catechol

The response currents obtained for tyrosinase-modified Teflon/graphite, carbon paste, and solid graphite electrodes in the presence of catechol are analyzed primarily using rotating disk electrode experiments. The rate-limiting steps, such as the electrochemical reduction of o-quinones and the enzymatic reduction of oxygen as well as the enzymatic oxidation of catechol, are theoretically considered and experimentally demonstrated for the different electrode configurations.     

The influence of moral schemas on the reconstruction of moral narratives in eighth graders and college students.

Much attention has been focused on the importance of reading moral stories to children (e.g., W. Bennett, 1993). Although research on general discourse comprehension is flourishing, little attention has been given to how moral discourse is understood by individuals; that is, what affects an individual's comprehension of a moral text? Eighth-grade and college students read and recalled four complex moral narratives in which moral arguments at different Kohlbergian stages were embedded. Participants then took the Defining Issues Test (DIT), a measure of moral judgment development. Those with higher reasoning scores on the DIT reconstructed more high-stage moral arguments during recall, including adding high-stage moral reasoning that was not in the original text. Significant age-level differences in cumulative moral judgment concepts were also found. Prior moral knowledge affected the comprehension of complex moral narratives. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Pseudopterosin Content Variability of the Purple Sea Whip Pseudopterogorgia elisabethae at the Islands of San Andres and Providencia (Sw Caribbean)

To determine pseudopterosin composition and concentration in colonies of Pseudopterogorgia elisabethae from the islands of San Andres and Providencia, we collected fragments of individual colonies at various sites and depth ranges around the islands. Chromatographic profiles of the polar fraction, particularly those obtained by HPLC-MS analyses, allowed us to recognize two different chemotypes. Chemotype 1 characterized samples from Providencia whereas chemotype 2 characterized samples from San Andres. A complex pseudopterosin mixture (compounds 1-13) characterized chemotype 1. These compounds were isolated by a combination of chromatographic methods and identified by spectroscopic methods (MS, UV, 1H, and 13C NMR). We identified the known pseudopterosins G and K and seco-pseudopterosin A. We also isolated and identified seven new compounds, pseudopterosins P-V, isomers of known pseudopterosins. Pseudopterosins G and K were found at concentrations ranging between 1 and 3% of the animal dry mass. Pseudopterosins Q and U were the major compounds reaching up to 6% of the animal dry mass at some locations. Major metabolites in chemotype 2 had a molecular weight and fragmentation pattern different from that observed in the pseudopterosins, as determined by HPLC-MS. Total pseudopterosin concentration in this chemotype was below 3% dry mass at all sites. Total pseudopterosin concentration was significantly higher in chemotype 1, with concentrations ranging between 4 and 20% dry mass. At most locations on Providencia, however, total pseudopterosin concentration ranged between 11 and 15% dry mass. Concentrations exceed reports from other locations in the Caribbean. Furthermore, pseudopterosin composition in our samples is quite different from those in specimens of P. elisabethae from the Bahamas and Bermuda. Pseudopterosins G, K, and P-V are characteristic of P. elisabethae colonies from the island of Providencia, while pseudopterosins A-D are characteristic of colonies of P. elisabethae from the Bahamas islands, and pseudopterosins E-L have been isolated from P. elisabethae from the Bahamas and Bermuda. The overall morphology of P. elisabethae can be variable, and chemical differences are not correlated to specific morphs. We confirmed the species identity of each colony by morphological and sclerite analysis and found no significant differences in sclerite dimensions among different colonies and chemotypes.     

The influence of reading purpose on inference generation and comprehension in reading.

There are variations in the extent to which particular types of inferences or activations are made during reading (G. McKoon & R. Ratcliff, 1992; M. Singer, 1994). In this study, the authors investigated the influence of reading purpose (for entertainment or study) on inference generation. Participants read 2 texts aloud and 2 texts for comprehension measures. Reading purpose did not influence off-line behavior (comprehension) but did influence on-line reader behavior (thinking aloud). Readers with a study purpose more often repeated the text, acknowledged a lack of background knowledge, and evaluated the text content and writing than did readers with an entertainment purpose. This pattern was stronger for the expository text than for the narrative text. Reading purpose, and possibly text type, affects the kinds of inferences that readers generate. Hence, inferential activities are at least partially under the reader's strategic control. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Median nerve neuropathy from an old lunate dislocation

We performed a histopathologic and immunohistochemical study of eyes obtained at autopsy of an 84-year-old man from a family with X-linked cone degeneration in which affected members have a 6.5-kilobase deletion in the red cone pigment gene. At his most recent ocular examination, at age 71 years, this patient had had a visual acuity of 20/200 OU, fundus changes suggestive of macular degeneration, borderline-normal full-field rod electroretinograms, and profoundly reduced full-field cone electroretinograms. Histopathologic examination demonstrated marked loss of cone and rod photoreceptors and the retinal pigment epithelium in the central macula. The peripheral cone population was reduced, while the peripheral rod population was relatively preserved. Immunohistochemical examination with an antibody to both red and green cone opsin and an antibody to blue cone opsin disclosed a prominent loss of the red and green cone population and preservation of the blue cone population. These findings show that a defect in the red cone pigment gene can result in extensive degeneration of the red and green cone population across the retina.     

The relation of multicultural experiences to moral judgment and mindsets.

Multicultural experience is considered to be beneficial, but it remains a difficult construct to measure. We tested the validity of a new assessment tool, the Multicultural Experiences Questionnaire (MEQ), using an undergraduate sample (N = 164), and examined the relation of multicultural experience to moral judgment, closed-mindedness, growth, and fixed mindsets. We expected that greater multicultural experience would be related to lower levels of closed-mindedness and higher levels of moral judgment and growth mindsets. Higher MEQ scores were correlated with decreased closed-mindedness and higher moral judgment scores. In regression analyses, controlling for age and sex, higher MEQ scores positively predicted participant scores on postconventional moral judgment and growth mindsets, but negatively predicted use of less developed moral judgment and fixed mindsets. Overall, these results support the validity of the MEQ and suggest that multicultural experiences are positively linked to measures of moral judgment and growth mindsets. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fermentation, degradation and microbial nitrogen partitioning for three forage colour phenotypes within anthocyanidin-accumulating Lc-alfalfa progeny

BACKGROUND: Alfalfa has the disadvantage of having a rapid initial rate of protein degradation, which results in pasture bloat, low efficiency of protein utilisation and excessive nitrogen (N) pollution into the environment for cattle. Introducing a gene that stimulates the accumulation of monomeric/polymeric anthocyanidins might reduce the ruminal protein degradation rate (by fixing protein and/or direct interaction with microbes) and additionally reduce methane emission. The objectives of this study were to evaluate in vitro fermentation, degradation and microbial N partitioning of three forage colour phenotypes (green, light purple‐green (LPG) and purple‐green (PG)) within newly developed Lc‐progeny and to compare them with those of parental green non‐transgenic (NT) alfalfa. RESULTS: PG‐Lc accumulated more anthocyanidin compared with Green‐Lc (P < 0.05), with LPG‐Lc intermediate. Volatile fatty acids and potentially degradable dry matter (DM) and N were similar among the four phenotypes. Gas, methane and ammonia accumulation rates were slower for the two purple‐Lc phenotypes compared with NT‐alfalfa (P < 0.05), while Green‐Lc was intermediate. Effective degradable DM and N were lower in the three Lc‐phenotypes (P < 0.05) compared with NT‐alfalfa. Anthocyanidin concentration was negatively correlated (P < 0.05) with gas and methane production rates and effective degradability of DM and N. CONCLUSION: The Lc‐alfalfa phenotypes accumulated anthocyanidin. Fermentation and degradation parameters indicated a reduced rate of fermentation and effective degradability for both purple anthocyanidin‐accumulating Lc‐alfalfa phenotypes compared with NT‐alfalfa. Copyright © 2012 Society of Chemical Industry     

Power electronic drives for magnetically triggered gels

Properly fabricated polymer gels exhibit an abrupt change in volume in response to a small change in an environmental parameter, such as temperature. The authors have developed gels that change in volume in response to an applied alternating magnetic field, and are working to apply these gels as actuators. This paper describes power electronic circuits suitable for electromagnetic activation of these polymer gels. Issues in the selection of circuit topologies for this application are discussed. Experimental results are presented, which demonstrate the magnetic activation of gels using prototype power electronic drives     

Moral theme comprehension in children.

Although some claim that reading moral stories to children will improve their moral literacy (see, e.g., W. Bennett, 1993), little research has been done that bears on this question. The purposes of this study were to (1) test the idea that children can extract the theme from a moral story and (2) test for developmental differences in moral theme comprehension. Participants from 3rd and 5th grades and a university were tested on whether they understood the lessons (i.e., the moral themes) from several moral stories. They were asked to identify both the theme from a list of message choices and which of 4 alternative vignettes had the same theme. Participants also rated the set of message and vignette choices for closeness of match to the original story. Reading comprehension was used as a covariate. Developmental differences in moral theme understanding were significant even after accounting for reading comprehension. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of California chaparral plants on in vitro ruminal fermentation of forage and concentrate diet

BACKGROUND: The combustible nature of chaparral plants has been attributed to the presence of secondary compounds such as phenolic acids, flavonoids and essential oils, among others. However, the implication of the antimicrobial properties of secondary compounds of chaparral in modulating rumen microbial metabolism has not been determined. The effects of 11 chaparral plants on rumen microbial fermentation were assessed in an in vitro batch culture fermentation fed a barley silage:barley grain‐based low concentrate (LC) and high concentrate (HC) diets. RESULTS: With LC, gas production [g dry matter (DM) incubated] and DM disappearance (DMD) were unaffected by Adenostoma fasciculatum, Ceanothus cuneatus, Baccharis pilularis or Eriodictyon californicum, but all plants except C. cuneatus decreased (P < 0.05) CH₄ production. With HC diet, all species except A. fasciculatum decreased (P < 0.01) total gas produced. Total volatile fatty acids (VFA) produced, molar proportions of acetate, propionate and butyrate, and the acetate:propionate (A:P) ratio were unaffected by chaparral addition to both HC and LC diets. Increased concentrations of A. fasciculatum and E. californicum decreased (linear; P < 0.05) fermentability and productions of CH₄ and NH₃‐N. CONCLUSION: Among all chaparral species investigated A. fasciculatum and E. californicum added as 10% of LC diet showed some potential to exert beneficial effects on rumen microbial fermentation. © Her Majesty the Queen in Right of Canada 2012