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CO2 reduction with protons and electrons at a boron-based reaction center.
Borohydrides are widely used reducing agents in chemical synthesis and have emerging energy applications as hydrogen storage materials and reagents for the reduction of CO2. Unfortunately, the high energy cost associated with the multistep preparation of borohydrides starting from alkali metals precludes large scale implementation of these latter uses. One potential solution to this issue is the direct synthesis of borohydrides from the protonation of reduced boron compounds. We herein report reactions of the redox series [Au(B2P2)] n (n = +1, 0, -1) (B2P2, 9,10-bis(2-(diisopropylphosphino)phenyl)-9,10-dihydroboranthrene) and their conversion into corresponding mono- and diborohydride complexes. Crucially, the monoborohydride can be accessed via protonation of [Au(B2P2)]-, a masked borane dianion equivalent accessible at relatively mild potentials (-2.05 V vs. Fc/Fc+). This species reduces CO2 to produce the corresponding formate complex. Cleavage of the formate complex can be achieved by reduction (ca. -1.7 V vs. Fc/Fc+) or by the addition of electrophiles including H+. Additionally, direct reaction of [Au(B2P2)]- with CO2 results in reductive disproportion to release CO and generate a carbonate complex. Together, these reactions constitute a synthetic cycle for CO2 reduction at a boron-based reaction center that proceeds through a B-H unit generated via protonation of a reduced borane with weak organic acids
Fluid de-icing tests on a Chandler-Evans 1900 CPB-3 carburetor mounted on a Pratt & Whitney R-1830-C4 intermediate rear engine section
A laboratory investigation of the icing characteristics of the Bendix-Stromberg carburetor model PD-12F5 with the Pratt and Whitney R-1830-C4 intermediate rear engine section
Moov: Scaffolding Motion-Based, Paired Play Creation
This project creates a motion-based play system that allows pairs of people to create their own play. It is an investigation in scaffolding an emergent play creation process. In it, players are placed in a minimal environment, given control over a digital body that emits movement-generated effects, and play emerges based on how players choose to express these effects in paired play. This paper describes the research and development that drove the creation of the system’s underlying play model and architecture, as well as the results of user testing. A variety of research approaches were undertaken in the project, including readings, interviews, low/high-fidelity prototyping, system architectural design and coding. Relevant research was explored in the areas of play, open-ended play, emergent play, and digital performance. The core objectives of the research were to build the system and then validate its efficacy
An Exploratory Study of Web-Based Electronic Commerce Applications
This study explores the use of the Web in electronic commerce (EC) applications and proposes a framework for classifying such applications. The framework is based on three widely used models of organizations that identify application categories. The ability of each of these models to classify thirty common EC applications was then examined. The Value Chain model provided the best schema and is used as a basis for the proposed framework. This new framework was evaluated with the observed EC applications from a random sample of Fortune 500 firms. The results of this classification process are presented along with an industry analysis of the observations. The analysis suggests that adoption of particular EC applications can be explained both by the nature of the industry and the nature of the application. The framework and tests suggest fruitful avenues for future research. In particular, testing a broader set of firms and refinement of the methodology would be advantageous
E-Hermes: An Xml Tool for the Classroom
This paper describes the development of an XML-based tool, called e-Hermes, suitable for use in a variety of instructional contexts. e-Hermes simulates the capabilities of a web-based system to handle customer order transactions and to apply both document structure (data format) validations and application (data content) validations. Students in Information Systems (IS) courses can use e-Hermes to support their learning about web-based database and system design principles, to practice using XML or to understand e-commerce transactions. Assignments are provided in this paper, along with an appendix for instructors who need more background in XML. This paper, therefore, presents important educational contributions in the field of information systems
Birthweight, HIV exposure and infant feeding as predictors of malnutrition in Botswanan infants
Background: A better understanding of the nutritional status of infants who are HIV-Exposed-Uninfected (HEU) and HIV-Unexposed-Uninfected (HUU) during their first 1000 days is key to improving population health, particularly in sub-Saharan Africa. Methods: A cross-sectional study compared the nutritional status, feeding practices and determinants of nutritional status of HEU and HUU infants residing in representative selected districts in Botswana during their first 1000 days of life. Four hundred and thirteen infants (37.3% HIV-exposed), aged 6–24 months, attending routine child health clinics, were recruited. Anthropometric, 24-h dietary intake and socio-demographic data was collected. Anthropometric Z-scores were calculated using 2006 World Health Organization growth standards. Modelling of the determinants of malnutrition was undertaken using logistic regression. Results: Overall, the prevalences of stunting, wasting and being underweight were 10.4%, 11.9% and 10.2%, respectively. HEU infants were more likely to be underweight (15.6% versus 6.9%), (P < 0.01) and stunted (15.6% versus 7.3%), (P < 0.05) but not wasted (P = 0.14) than HUU infants. HEU infants tended to be formula fed (82.5%), whereas HUU infants tended to breastfeed (94%) for the first 6 months (P < 0.001). Significant predictors of nutritional status were HIV exposure, birthweight, birth length, APGAR (appearance, pulse, grimace, activity and respiration) score and mother/caregiver's education with little influence of socio-economic status. Conclusions: HEU infants aged 6–24 months had worse nutritional status compared to HUU infants. Low birthweight was the main predictor of undernutrition in this population. Optimisation of infant nutritional status should focus on improving birthweight. In addition, specific interventions should target HEU infants aiming to eliminate growth disparity between HEU and HUU infants.</p
Extensive genome analysis of Coxiella burnetii reveals limited evolution within genomic groups
This is the final version. Available on open access from BMC via the DOI in this recordAvailability of data and materials:
Whole genome sequences were deposited in NCBI under BioProjects PRJNA430350 and PRJNA506366, as well as in the Sequence Read Archive as studies SRP130048 and SRP170036. Individual GenBank accession numbers for the WGS data are as follows: Q532 = PPFQ00000000.1 ; Q540 = PPFP00000000.1 ; Q545 = PPFO00000000.1 ; Q556 = PPFN00000000.1 ; Q559 = PPFM00000000.1 ; Cb_D1 = RQJU00000000.1; Cb_D2 = RQJT00000000.1 ; Cb_D8 = RQJS00000000.1 ; and Cb_D10 = RQJR00000000.1 .The authors declare that all other data supporting the findings of this study are available within the article and its supplementary information files.Background: Coxiella burnetii is a zoonotic pathogen that resides in wild and domesticated animals across the globe and causes a febrile illness, Q fever, in humans. An improved understanding of the genetic diversity of C. burnetii is essential for the development of diagnostics, vaccines and therapeutics, but genotyping data is lacking from many parts of the world. Sporadic outbreaks of Q fever have occurred in the United Kingdom, but the local genetic make-up of C. burnetii has not been studied in detail. Results: Here, we report whole genome data for nine C. burnetii sequences obtained in the UK. All four genomes of C. burnetii from cattle, as well as one sheep sample, belonged to Multi-spacer sequence type (MST) 20, whereas the goat samples were MST33 (three genomes) and MST32 (one genome), two genotypes that have not been described to be present in the UK to date. We established the phylogenetic relationship between the UK genomes and 67 publically available genomes based on single nucleotide polymorphisms (SNPs) in the core genome, which confirmed tight clustering of strains within genomic groups, but also indicated that sub-groups exist within those groups. Variation is mainly achieved through SNPs, many of which are non-synonymous, thereby confirming that evolution of C. burnetii is based on modification of existing genes. Finally, we discovered genomic-group specific genome content, which supports a model of clonal expansion of previously established genotypes, with large scale dissemination of some of these genotypes across continents being observed. Conclusions: The genetic make-up of C. burnetii in the UK is similar to the one in neighboring European countries. As a species, C. burnetii has been considered a clonal pathogen with low genetic diversity at the nucleotide level. Here, we present evidence for significant variation at the protein level between isolates of different genomic groups, which mainly affects secreted and membrane-associated proteins. Our results thereby increase our understanding of the global genetic diversity of C. burnetii and provide new insights into the evolution of this emerging zoonotic pathogen.Defence Science and Technology Laboratory (DSTL
GPS and TOPEX mid-latitude trough observations in the southern hemisphere at low sunspot numbers
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