Steam reforming on transition-metal carbides from density-functional theory

A screening study of the steam reforming reaction (CH_4 + H_2O -> CO + 3H_2) on early transition-metal carbides (TMC's) is performed by means of density-functional theory calculations. The set of considered surfaces includes the alpha-Mo_2C(100) surfaces, the low-index (111) and (100) surfaces of TiC, VC, and delta-MoC, and the oxygenated alpha-Mo_2C(100) and TMC(111) surfaces. It is found that carbides provide a wide spectrum of reactivities towards the steam reforming reaction, from too reactive via suitable to too inert. The reactivity is discussed in terms of the electronic structure of the clean surfaces. Two surfaces, the delta-MoC(100) and the oxygen passivated alpha-Mo_2C(100) surfaces, are identified as promising steam reforming catalysts. These findings suggest that carbides provide a playground for reactivity tuning, comparable to the one for pure metals.Comment: 6 pages, 4 figure

miR-17* Suppresses Tumorigenicity of Prostate Cancer by Inhibiting Mitochondrial Antioxidant Enzymes

Aberrant micro RNA (miRNA) expression has been implicated in the pathogenesis of cancer. Recent studies have shown that the miR-17-92 cluster is overexpressed in many types of cancer. The oncogenic function of mature miRNAs encoded by the miR-17–92 cluster has been identified from the 5′ arm of six precursors. However, the function of the miRNAs produced from the 3′ arm of these precursors remains unknown. The present study demonstrates that miR-17* is able to suppress critical primary mitochondrial antioxidant enzymes, such as manganese superoxide dismutase (MnSOD), glutathione peroxidase-2 (GPX2) and thioredoxin reductase-2 (TrxR2). Transfection of miR-17* into prostate cancer PC-3 cells significantly reduces levels of the three antioxidant proteins and activity of the luciferase reporter under the control of miR-17* binding sequences located in the 3′-untranslated regions of the three target genes. Disulfiram (DSF), a dithiolcarbomate drug shown to have an anticancer effect, induces the level of mature miR-17* and cell death in PCa cells, which can be attenuated by transfection of antisense miR-17*. Increasing miR-17* level in PC-3 cells by a Tet-on based conditional expression system markedly suppresses its tumorigencity. These results suggest that miR-17* may suppress tumorigenicity of prostate cancer through inhibition of mitochondrial antioxidant enzymes

Can improving working memory prevent academic difficulties? A school based randomised controlled trial.

BACKGROUND: Low academic achievement is common and is associated with adverse outcomes such as grade repetition, behavioural disorders and unemployment. The ability to accurately identify these children and intervene before they experience academic failure would be a major advance over the current 'wait to fail' model. Recent research suggests that a possible modifiable factor for low academic achievement is working memory, the ability to temporarily store and manipulate information in a 'mental workspace'. Children with working memory difficulties are at high risk of academic failure. It has recently been demonstrated that working memory can be improved with adaptive training tasks that encourage improvements in working memory capacity. Our trial will determine whether the intervention is efficacious as a selective prevention strategy for young children at risk of academic difficulties and is cost-effective. METHODS/DESIGN: This randomised controlled trial aims to recruit 440 children with low working memory after a school-based screening of 2880 children in Grade one. We will approach caregivers of all children from 48 participating primary schools in metropolitan Melbourne for consent. Children with low working memory will be randomised to usual care or the intervention. The intervention will consist of 25 computerised working memory training sessions, which take approximately 35 minutes each to complete. Follow-up of children will be conducted at 6, 12 and 24 months post-randomisation through child face-to-face assessment, parent and teacher surveys and data from government authorities. The primary outcome is academic achievement at 12 and 24 months, and other outcomes include child behaviour, attention, health-related quality of life, working memory, and health and educational service utilisation. DISCUSSION: A successful start to formal learning in school sets the stage for future academic, psychological and economic well-being. If this preventive intervention can be shown to be efficacious, then we will have the potential to prevent academic underachievement in large numbers of at-risk children, to offer a ready-to-use intervention to the Australian school system and to build international research partnerships along the health-education interface, in order to carry our further studies of effectiveness and generalisability.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are

SOD2 immunoexpression predicts lymph node metastasis in penile cancer

BACKGROUND: Superoxide dismutase-2 (SOD2) is considered one of the most important antioxidant enzymes that regulate cellular redox state in normal and tumorigenic cells. Overexpression of this enzyme in lung, gastric, colorectal, breast cancer and cervical cancer malignant tumors has been observed. Its relationship with inguinal lymph node metastasis in penile cancer is unknown. METHODS: SOD2 protein expression levels were determined by immunohistochemistry in 125 usual type squamous cell carcinomas of the penis from a Brazilian cancer center. The casuistic has been characterized by means of descriptive statistics. An exploratory logistic regression has been proposed to evaluate the independent predictive factors of lymph node metastasis. RESULTS: SOD2 expression in more than 50% of cells was observed in 44.8% of primary penile carcinomas of the usual type. This expression pattern was associated with lymph node metastasis both in the uni and multivariate analysis. CONCLUSIONS: Our results indicate that SOD2 expression predicts regional lymph node metastasis. The potential clinical implication of this observation warrants further studies.Dr. Lara Termini (FAPESP 2005/57274-9); Dr. Luisa Lina Villa (FAPESP 2008/57889-1 and CNPq 573799/2008-3)

Executive difficulties in Developmental Coordination Disorder: Methodological issues and future directions

Motor skills and cognition have often been studied separately, but there is increasing understanding of the close relationship between these abilities over development. Motor coordination difficulties are central to the diagnosis of Developmental Coordination Disorder (DCD), and recent evidence suggests that certain cognitive processes, known as ‘executive functions’, may be affected in individuals with this neurodevelopmental disorder. In this article, we review the research concerning executive functions in DCD, considering behavioural, neuroimaging and questionnaire studies of a range of processes. We highlight methodological issues relating to our current understanding of executive functioning difficulties in DCD, including problems with interpretation of results based on the tasks used. We suggest future directions for research in this area, including the relationship of laboratory research to interventions within ‘real-world’ contexts

Does audio‐visual binding as an integrative function of working memory influence the early stages of learning to write?

Working memory has been proposed to account for the differential rates in pro- gress young children make in writing. One crucial aspect of learning to write is the encoding (i.e., integration) and retrieval of the correct phoneme–grapheme pairings, known as binding. In addition to executive functions, binding is regarded as central to the concept of working memory. To test the developmental increase in binding ability and its comparative influence on writing, an experimental study assessed 5- and 6-year-olds’ accuracy in retaining and retrieving bound audio-visual information alongside measures of verbal and visual complex working memory span (i.e., cen- tral executive functions), and transcription skills (i.e., alphabet and spelling). Results demonstrated an age-related increase in the ability to bind, and that binding had sig- nificant associations with working memory and early writing ability, but once bind- ing and age were controlled for it was verbal working memory that made an inde- pendent contribution to individual differences in writing performance. Although the contribution this paper made was through an exploration and expansion of theoreti- cal ideas within writing research, it is likely to make an important practical contribu- tion to instruction in the future both at the level of transcription and text generation as writers develop those skills

Buses, cars, bicycles and walkers the influence of the type of human transport on the flight responses of waterbirds

One way to manage disturbance to waterbirds in natural areas where humans require access is to promote the occurrence of stimuli for which birds tolerate closer approaches, and so cause fewer responses. We conducted 730 experimental approaches to 39 species of waterbird, using five stimulus types (single walker, three walkers, bicycle, car and bus) selected to mimic different human management options available for a controlled access, Ramsar-listed wetland. Across species, where differences existed (56% of 25 cases), motor vehicles always evoked shorter flight-initiation distances (FID) than humans on foot. The influence of stimulus type on FID varied across four species for which enough data were available for complete cross-stimulus analysis. All four varied FID in relation to stimuli, differing in 4 to 7 of 10 possible comparisons. Where differences occurred, the effect size was generally modest, suggesting that managing stimulus type (e.g. by requiring people to use vehicles) may have species-specific, modest benefits, at least for the waterbirds we studied. However, different stimulus types have different capacities to reduce the frequency of disturbance (i.e. by carrying more people) and vary in their capacity to travel around important habita

Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)1.

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field

The Monkey game: A computerized verbal working memory task for self-reliant administration in primary school children

Contains fulltext : 178254.pdf (publisher's version ) (Open Access)In two studies, the psychometric properties of an online self-reliant verbal working memory task (the Monkey game) for primary school children (6-12 years of age) were examined. In Study 1, children (n = 5,203) from 31 primary schools participated. The participants completed computerized verbal and visual-spatial working memory tasks (i.e., the Monkey game and the Lion game) and a paper-and-pencil version of Raven's Standard Progressive Matrices. Reading comprehension and math achievement test scores were obtained from the schools. First, the internal consistency of the Monkey game was examined. Second, multilevel modeling was used to examine the effects of classroom membership. Multilevel multivariate regression analysis was used to examine the Monkey game's concurrent relationship with the Lion game and its predictive relationships with reading comprehension and math achievement. Also, age-related differences in performance were examined. In Study 2, the concurrent relationships between the Monkey game and two tester-led computerized working memory tasks were further examined (n = 140). Also, the 1- and 2-year stability of the Monkey game was investigated. The Monkey game showed excellent internal consistency, good concurrent relationships with the other working memory measures, and significant age differences in performance. Performance on the Monkey game was also predictive of subsequent reading comprehension and mathematics performance, even after controlling for individual differences in intelligence. Performance on the Monkey game was influenced by classroom membership. The Monkey game is a reliable and suitable instrument for the online computerized and self-reliant assessment of verbal working memory in primary school children.16 p

Quantifying sources and sinks of reactive gases in the lower atmosphere using airborne flux observations

Atmospheric composition is governed by the interplay of emissions, chemistry, deposition, and transport. Substantial questions surround each of these processes, especially in forested environments with strong biogenic emissions. Utilizing aircraft observations acquired over a forest in the southeast U.S., we calculate eddy covariance fluxes for a suite of reactive gases and apply the synergistic information derived from this analysis to quantify emission and deposition fluxes, oxidant concentrations, aerosol uptake coefficients, and other key parameters. Evaluation of results against state-of-the-science models and parameterizations provides insight into our current understanding of this system and frames future observational priorities. As a near-direct measurement of fundamental process rates, airborne fluxes offer a new tool to improve biogenic and anthropogenic emissions inventories, photochemical mechanisms, and deposition parameterizations. Key Points Airborne flux observations for a suite of reactive gases Direct constraints on production, loss, and surface-atmosphere exchange Comprehensive evaluation of chemical budgets over a temperate fores