Kinetic and mechanistic evaluation of tetrahydroborate ion electro-oxidation at polycrystalline gold

The anodic oxidation of tetrahydroborate ion is studied in NaOH at stationary and rotating polycrystalline Au disk electrodes. Linear sweep and cyclic voltammetry are applied varying the scan and rotation rate from 0.005 to 51.200 V s⁻¹ and from 52.3 to 314.1 rad s⁻¹, correspondingly. The effects of variation of BH₄⁻ and NaOH concentrations as well as of the potential limits of the ranges studied have been initially followed. Most of the experiments have been carried out with 10.9 mM NaBH₄ in 1.04 M NaOH at 293 K in the potential range from −1.300 to 0.900 V (vs. Ag/AgCl). It is found that 6 electrons are exchanged in the overall oxidation transformation. The kinetic analysis of the processes determining the two anodic peaks recorded under static conditions at scan rates lower than 0.500 V s⁻¹ shows that 1.4 electrons are exchanged in the potential range of the first one (at ca −0.5 V), while the rate of the second one (at ca +0.3 V) is determined by a quasi-reversible 1-electron transfer reaction. A kinetic evidence for the participation of surface bound intermediates in the electro-oxidation process is provided. Two additional well outlined anodic peaks are recorded in the aforementioned potential range under specific experimental conditions. A quasi-8 electron mechanism involving four oxidation and hydrolysis steps is advanced to explain the experimental results. It accounts for the involvement of borohydride oxidation species and the Au⁺/Au³⁺ mediator couple.     

Combining linguistic resources to create a machine-tractable Japanese-Malay dictionary

We present a method for combining two bilingual dictionaries to make a third, using one language as a pivot. In this case we combine a Japanese-English dictionary with a Malay-English dictionary, to produce a Japanese-Malay dictionary. Our method differs from previous methods in its improved matching through normalization of the pivot language. We have made a prototype dictionary of around 76,000 Japanese-Malay pairs for 50,000 Japanese head words.     

Acidic urine pH is associated with elevated levels of free urinary benzidine and N-acetylbenzidine and urothelial cell DNA adducts in exposed workers

We evaluated the influence of urine pH on the proportion of urinary benzidine (BZ) and N-acetylbenzidine present in the free, unconjugated state and on exfoliated urothelial cell DNA adduct levels in 32 workers exposed to BZ in India. Postworkshift urine pH was inversely correlated with the proportions of BZ (r = -0.78; P < 0.0001) and N-acetylbenzidine (r = -0.67; P < 0.0001) present as free compounds. Furthermore, the average of each subject's pre- and postworkshift urine pH was negatively associated with the predominant urothelial DNA adduct (P = 0.0037, adjusted for urinary BZ and metabolites), which has been shown to cochromatograph with a N-(3'-phosphodeoxyguanosin-8-yl)-N'-acetylbenzidine adduct standard. Controlling for internal dose, individuals with urine pH < 6 had 10-fold higher DNA adduct levels compared to subjects with urine pH > or = 7. As reported previously, polymorphisms in NAT1, NAT2, and GSTM1 had no impact on DNA adduct levels. This is the first study to demonstrate that urine pH has a strong influence on the presence of free urinary aromatic amine compounds and on urothelial cell DNA adduct levels in exposed humans. Because there is evidence that acidic urine has a similar influence on aromatic amines derived from cigarette smoke, urine pH, which is influenced by diet, may be an important susceptibility factor for bladder cancer caused by tobacco in the general population.     

Factor structure integrity of the Personal Attributes Questionnaire: An English–French comparison.

The Personal Attributes Questionnaire (PAQ) is one of the pre-eminent measures of gender-specific personality characteristics. To evaluate the PAQ'S viability 20 yrs after its creation, the authors assessed the dimensionality and psychometric properties of the original PAQ and a French version using samples of 637 English-speaking and French-speaking university administrators. The structure of the English form of the PAQ was supported for both women and men when the data were submitted to confirmatory analyses. Support was not as convincing for the dimensionality of the French form of the PAQ, however. Some evidence for expected differences in mean Instrumentality and Expressivity scores was found between women and men. Findings support the continued use of the English PAQ as a measure of Instrumental and Expressive personality traits. Further study of the French PAQ is recommended. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Beyond the pages of a book: Interactive book reading and language development in preschool classrooms.

The effects of a book reading technique called interactive book reading on the language and literacy development of 4 yr olds from low-income families were evaluated. Teachers read books to children and reinforced the vocabulary in the books by presenting concrete objects that represented the words and by providing children with multiple opportunities to use the book-related words. The teachers also were trained to ask open-ended questions and to engage children in conversations about the book and activities. This provided children with opportunities to use language and learn vocabulary in a meaningful context. Children who were in the interactive book reading intervention group scored significantly better than children in the comparison group on Peabody Picture Vocabulary Test—III and other measures of receptive and expressive language. Book reading and related activities can promote the development of language and literacy skills in young children. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Predictive validity of situational assessment at a psychiatric rehabilitation center.

Used situational assessment to predict employment outcomes for 77 individuals (mean age 24.5 yrs) attending a community psychiatric rehabilitation program. The assessment form was a 22-item checklist comprised of 4 dimensions: work readiness, work attitudes, interpersonal relations, and work quality. Ratings were made in 2 work settings: prevocational work crews and transitional employment. Situational assessment predicted outcome better than did work history. Staff ratings were significantly higher for Ss working in transitional employment, although ratings made in both settings were predictive of later employment outcomes. It is concluded that situational assessment may be a method better suited for screening out members who have poor work potential than selecting members who will definitely succeed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Isolation of cDNA clones from an osteosarcoma-ROS17/2.8 library by differential hybridization

We have used differential hybridization to isolate and characterize two novel cDNAs expressed in chondrocytes and some osteoblastic cells. A rat osteosarcoma ROS17/2.8 cDNA library was screened and cDNA clones hybridizing strongly to radiolabeled porcine calvaria cDNA but weakly to a control radiolabeled cDNA were isolated. Two clones were obtained--p.6.1 and p.10.15. A radiolabeled probe of p10.15 was shown to hybridize specifically to a 2.3 Kb message RNA from a chondrogenic clonal cell population from rat calvaria-RCJ 3.1C5.18, and the mRNA was downregulated by 1,25 (OH)2D3, which inhibits chondrogenesis in these cells. The other clone, p6.1, was found to hybridize to a 0.95 Kb message that is expressed in rat liver, kidney, lung, muscle, and brain, but not expressed in spleen and expressed only in low levels in thymus.     

Examining the ecological consequences of restoring flow intermittency to artificially perennial lowland streams: Patterns and predictions from the Broken—Boosey creek system in northern Victoria,Australia

The reinstatement of natural flow regimes is a rapidly emerging issue in river restoration worldwide. In northern Victoria, Australia, efforts are presently underway to restore a natural, intermittent flow regime to several streams which have received perennial diversions for both irrigation and stock and domestic water‐supplies for over 100 years. A pipeline to deliver water to landholders will significantly reduce transmission losses throughout the system allowing irrigation canals and diversion weirs to be decommissioned. The motivation for flow alteration in this system lies primarily in reducing inefficiencies in water delivery which, in turn, will be used to meet escalating demands on water resources. The ecological impact of the flow regime shift on these streams is likely to be substantial. This study utilized an existing artificial hydrological gradient (from perennial to intermittent) in two creek systems, to explore relationships between flow regime and a range of ecological variables. These data provide a benchmark against which to assess ecological changes once flow has been altered and form the basis for predicting changes that can assist future management decisions. Data collected from 10 sites across a strong hydrological gradient detected clear differences in geomorphology, water quality and biotic assemblages (macrophytes, macroinvertebrates and fish). By examining the relationship between flow regime and the distribution of biota we identify both the positive and negative outcomes of restoring naturally intermittent flow regimes within artificially perennial lowland streams. The reinstatement of intermittent flow regimes in artificially perennial streams will continue in many parts of the world as water delivery via these systems becomes increasingly uneconomical. While flow restoration may in principle be regarded as a positive step, these findings emphasize the need to consider fully the ecological consequences of restoring historical hydrological regimes to streams within the context of other human induced catchment disturbances. Copyright © 2009 John Wiley & Sons, Ltd.