Characterisation of Spray Development from Spark-Eroded and Laser-Drilled Multihole Injectors in an Optical DISI Engine and in a Quiescent Injection Chamber

This paper addresses the need for fundamental understanding of the mechanisms of fuel spray formation and mixture preparation in direct injection spark ignition (DISI) engines. Fuel injection systems for DISI engines undergo rapid developments in their design and performance, therefore, their spray breakup mechanisms in the physical conditions encountered in DISI engines over a range of operating conditions and injection strategies require continuous attention. In this context, there are sparse data in the literature on spray formation differences between conventionally drilled injectors by spark erosion and latest Laser-drilled injector nozzles. A comparison was first carried out between the holes of spark-eroded and Laser-drilled injectors of same nominal type by analysing their in-nozzle geometry and surface roughness under an electron microscope. Then the differences in their spray characteristics under quiescent conditions, as well as in a motoring optical engine, are discussed on the basis of high-speed imaging experiments and image processing methods. Specifically, the spray development mechanism was quantified by spray tip penetration and cone angle data under a range of representative low-load and high-low engine operating conditions (0.5 bar and 1.0 bar absolute, respectively), as well as at low and high injector body temperatures (20 °C and 90 °C) to represent cold and warm engine-head conditions. Droplet sizing was also performed with the two injectors using Phase Doppler Anemometry in a quiescent chamber

Development of a Real-Size Optical Injector Nozzle for Studies of Cavitation, Spray Formation and Flash Boiling at Conditions Relevant to Direct-Injection Spark-Ignition Engines

High-pressure multi-hole injectors for direct-injection spark-ignition engines have shown enhanced fuel atomisation and flexibility in fuel targeting by selection of the number and angle of the nozzle holes. The nozzle internal flow is known to influence the characteristics of spray formation; hence, understanding its mechanisms is essential for improving mixture preparation. However, currently, no data exist for fuel temperatures representative of real engine operation, especially at low-load high-temperature conditions with early injection strategies that can lead to phase change due to fuel flash-boiling upon injection. This challenge is further complicated by the predicted fuel stocks, which may include new (e.g. bio-derived) components. The physical/chemical properties of such components can differ markedly from gasoline, and it is important to have the capability to study their effects on in-nozzle flow and spray formation, taking under consideration their different chemical compatibilities with optical materials as well. The current article presents the design and development of a real-size quartz optical nozzle, 200 µm in diameter, suitable for high-temperature applications and also compatible with new fuels such as alcohols. First, the internal geometry of a typical real multi-hole injector was analysed by electron microscopy. Mass flow was measured, and relevant fluid mechanics dimensionless parameters were derived. Laser and mechanical drilling of the quartz nozzle holes were compared. Abrasive flow machining of the optical nozzles was also performed and analysed by microscopy in comparison to the real injector. Initial validation results with a high-speed camera showed successful imaging of microscopic in-nozzle flow and cavitation phenomena, coupled to downstream spray formation, under a variety of conditions including high fuel temperature flash-boiling effects. The current work used gasoline and iso-octane to provide proof-of-concept images of the optical nozzle, and future work will include testing of a range of fuels, some of which will also be bio-derived

The complete sequence of the Acacia ligulata chloroplast genome reveals a highly divergent clpP1 gene

Legumes are a highly diverse angiosperm family that include many agriculturally important species. To date, 21 complete chloroplast genomes have been sequenced from legume crops confined to the Papilionoideae subfamily. Here we report the first chloroplast genome from the Mimosoideae, Acacia ligulata, and compare it to the previously sequenced legume genomes. The A. ligulata chloroplast genome is 158,724 bp in size, comprising inverted repeats of 25,925 bp and single-copy regions of 88,576 bp and 18,298 bp. Acacia ligulata lacks the inversion present in many of the Papilionoideae, but is not otherwise significantly different in terms of gene and repeat content. The key feature is its highly divergent clpP1 gene, normally considered essential in chloroplast genomes. In A. ligulata, although transcribed and spliced, it probably encodes a catalytically inactive protein. This study provides a significant resource for further genetic research into Acacia and the Mimosoideae. The divergent clpP1 gene suggests that Acacia will provide an interesting source of information on the evolution and functional diversity of the chloroplast Clp protease comple

On the Origin of S0 Galaxies

I will review the basic properties of S0 galaxies in the local Universe in relation to both elliptical and spiral galaxies, their neighbours on the Hubble sequence, and also in relation to dwarf spheroidal (dSph) galaxies. This will include colours, luminosities, spectral features, information about the age and metallicity composition of their stellar populations and globular clusters, about their ISM content, as well as kinematic signatures and their implications for central black hole masses and past interaction events, and the number ratios of S0s to other galaxy types in relation to environmental galaxy density. I will point out some caveats as to their morphological discrimination against other classes of galaxies, discuss the role of dust and the wavelength dependence of bulge/disk light ratios. These effects are of importance for investigations into the redshift evolution of S0 galaxies -- both as individual objects and as a population. The various formation and transformation scenarios for S0 and dSph galaxies will be presented and confronted with the available observations.Comment: Invited Review, 18 pages, ``BARS 2004'' Conference, South Africa, June 2004, eds.: K. C. Freeman, D. L. Block, I. Puerari, R. Groess, Kluwer, in pres

On the sources of the height–intelligence correlation: New insights from a bivariate ACE model with assortative mating

A robust positive correlation between height and intelligence, as measured by IQ tests, has been established in the literature. This paper makes several contributions toward establishing the causes of this association. First, we extend the standard bivariate ACE model to account for assortative mating. The more general theoretical framework provides several key insights, including formulas to decompose a cross-trait genetic correlation into components attributable to assortative mating and pleiotropy and to decompose a cross-trait within-family correlation. Second, we use a large dataset of male twins drawn from Swedish conscription records and examine how well genetic and environmental factors explain the association between (i) height and intelligence and (ii) height and military aptitude, a professional psychogologist’s assessment of a conscript’s ability to deal with wartime stress. For both traits, we find suggestive evidence of a shared genetic architecture with height, but we demonstrate that point estimates are very sensitive to assumed degrees of assortative mating. Third, we report a significant within-family correlation between height and intelligence \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$(\hat{\rho}=0.10),$$\end{document} suggesting that pleiotropy might be at play

One step closer to understanding the role of bacteria in diabetic foot ulcers: characterising the microbiome of ulcers

Background: The aim of this study was to characterise the microbiome of new and recurrent diabetic foot ulcers using 16S amplicon sequencing (16S AS), allowing the identification of a wider range of bacterial species that may be important in the development of chronicity in these debilitating wounds. Twenty patients not receiving antibiotics for the past three months were selected, with swabs taken from each individual for culture and 16S AS. DNA was isolated using a combination of bead beating and kit extraction. Samples were sequenced on the Illumina Hiseq 2500 platform. Results: Conventional laboratory culture showed positive growth from only 55 % of the patients, whereas 16S AS was positive for 75 % of the patients (41 unique genera, representing 82 different operational taxonomic units (OTU’s). S. aureus was isolated in 72 % of culture-positive samples, whereas the most commonly detected bacteria in all ulcers were Peptoniphilusspp., Anaerococcus spp. and Corynebacterium spp., with the addition of Staphylococcus spp. in new ulcers. The majority of OTU’s residing in both new and recurrent ulcers (over 67 %) were identified as facultative or strict anaerobic Gram-positive organisms. Principal component analysis (PCA) showed no difference in clustering between the two groups (new and recurrent ulcers). Conclusions: The abundance of anaerobic bacteria has important implications for treatment as it suggests that the microbiome of each ulcer “starts afresh” and that, although diverse, are not distinctly different from one another with respect to new or recurrent ulcers. Therefore, when considering antibiotic therapy the duration of current ulceration may be a more important consideration than a history of healed ulcer

Single nucleotide polymorphism-based genome-wide linkage analysis in Japanese atopic dermatitis families

<p>Abstract</p> <p>Background</p> <p>Atopic dermatitis develops as a result of complex interactions between several genetic and environmental factors. To date, 4 genome-wide linkage studies of atopic dermatitis have been performed in Caucasian populations, however, similar studies have not been done in Asian populations. The aim of this study was to identify chromosome regions linked to atopic dermatitis in a Japanese population.</p> <p>Methods</p> <p>We used a high-density, single nucleotide polymorphism genotyping assay, the Illumina BeadArray Linkage Mapping Panel (version 4) comprising 5,861 single nucleotide polymorphisms, to perform a genome-wide linkage analysis of 77 Japanese families with 111 affected sib-pairs with atopic dermatitis.</p> <p>Results</p> <p>We found suggestive evidence for linkage with 15q21 (LOD = 2.01, NPL = 2.87, <it>P </it>= .0012) and weak linkage to 1q24 (LOD = 1.26, NPL = 2.44, <it>P </it>= .008).</p> <p>Conclusion</p> <p>We report the first genome-wide linkage study of atopic dermatitis in an Asian population, and novel loci on chromosomes 15q21 and 1q24 linked to atopic dermatitis. Identification of novel causative genes for atopic dermatitis will advance our understanding of the pathogenesis of atopic dermatitis.</p

Hypermethylation of the DLC1 CpG island does not alter gene expression in canine lymphoma

<p>Abstract</p> <p>Background</p> <p>This study is a comparative epigenetic evaluation of the methylation status of the <it>DLC1 </it>tumor suppressor gene in naturally-occurring canine lymphoma. Canine non-Hodgkin's lymphoma (NHL) has been proposed to be a relevant preclinical model that occurs spontaneously and may share causative factors with human NHL due to a shared home environment. The canine <it>DLC1 </it>mRNA sequence was derived from normal tissue. Using lymphoid samples from 21 dogs with NHL and 7 normal dogs, the methylation status of the promoter CpG island of the gene was defined for each sample using combined bisulfite restriction analysis (COBRA), methylation-specific PCR (MSP), and bisulfite sequencing methods. Relative gene expression was determined using real-time PCR.</p> <p>Results</p> <p>The mRNA sequence of canine <it>DLC1 </it>is highly similar to the human orthologue and contains all protein functional groups, with 97% or greater similarity in functional regions. Hypermethylation of the 5' and 3' flanking regions of the promoter was statistically significantly associated with the NHL phenotype, but was not associated with silencing of expression or differences in survival.</p> <p>Conclusion</p> <p>The canine <it>DLC1 </it>is constructed highly similarly to the human gene, which has been shown to be an important tumor suppressor in many forms of cancer. As in human NHL, the promoter CpG island of <it>DLC1 </it>in canine NHL samples is abnormally hypermethylated, relative to normal lymphoid tissue. This study confirms that hypermethylation occurs in canine cancers, further supporting the use of companion dogs as comparative models of disease for evaluation of carcinogenesis, biomarker diagnosis, and therapy.</p

In Vivo Expression of MHC Class I Genes Depends on the Presence of a Downstream Barrier Element

Regulation of MHC class I gene expression is critical to achieve proper immune surveillance. In this work, we identify elements downstream of the MHC class I promoter that are necessary for appropriate in vivo regulation: a novel barrier element that protects the MHC class I gene from silencing and elements within the first two introns that contribute to tissue specific transcription. The barrier element is located in intergenic sequences 3′ to the polyA addition site. It is necessary for stable expression in vivo, but has no effect in transient transfection assays. Accordingly, in both transgenic mice and stably transfected cell lines, truncation of the barrier resulted in transcriptional gene silencing, increased nucleosomal density and decreased histone H3K9/K14 acetylation and H3K4 di-methylation across the gene. Significantly, distinct sequences within the barrier element govern anti-silencing and chromatin modifications. Thus, this novel barrier element functions to maintain transcriptionally permissive chromatin organization and prevent transcriptional silencing of the MHC class I gene, ensuring it is poised to respond to immune signaling