Material Characterization and Real-Time Wear Evaluation of Pistons and Cylinder Liners of the Tiger 131 Military Tank

Material characterisation and wear evaluation of the original and replacement pistons and cylinder-liners of Tiger 131 is reported. Original piston and cylinder-liner were operative in the Tigers’ engine during WWII. The replacement piston and cylinder-liner were used as substitutes and were obtained after failure in two hours of operation in the actual engine. Material characterisation revealed that the original piston was aluminium silicon hypereutectic alloy whereas the replacement piston was aluminium copper alloy with very low silicon content. Both original and replacement cylinder-liners consisted of mostly iron which is indicative of cast iron, a common material for this application. The replacement piston average surface roughness was found to be 9.09 μm while for replacement cylinder-liner it was 5.78 μm

Expression of PEG11 and PEG11AS transcripts in normal and callipyge sheep

BACKGROUND: The callipyge mutation is located within an imprinted gene cluster on ovine chromosome 18. The callipyge trait exhibits polar overdominant inheritance due to the fact that only heterozygotes inheriting a mutant paternal allele (paternal heterozygotes) have a phenotype of muscle hypertrophy, reduced fat and a more compact skeleton. The mutation is a single A to G transition in an intergenic region that results in the increased expression of several genes within the imprinted cluster without changing their parent-of-origin allele-specific expression. RESULTS: There was a significant effect of genotype (p < 0.0001) on the transcript abundance of DLK1, PEG11, and MEG8 in the muscles of lambs with the callipyge allele. DLK1 and PEG11 transcript levels were elevated in the hypertrophied muscles of paternal heterozygous animals relative to animals of the other three genotypes. The PEG11 locus produces a single 6.5 kb transcript and two smaller antisense strand transcripts, referred to as PEG11AS, in skeletal muscle. PEG11AS transcripts were detectable over a 5.5 kb region beginning 1.2 kb upstream of the PEG11 start codon and spanning the entire open reading frame. Analysis of PEG11 expression by quantitative PCR shows a 200-fold induction in the hypertrophied muscles of paternal heterozygous animals and a 13-fold induction in homozygous callipyge animals. PEG11 transcripts were 14-fold more abundant than PEG11AS transcripts in the gluteus medius of paternal heterozygous animals. PEG11AS transcripts were expressed at higher levels than PEG11 transcripts in the gluteus medius of animals of the other three genotypes. CONCLUSIONS: The effect of the callipyge mutation has been to alter the expression of DLK1, GTL2, PEG11 and MEG8 in the hypertrophied skeletal muscles. Transcript abundance of DLK1 and PEG11 was highest in paternal heterozygous animals and exhibited polar overdominant gene expression patterns; therefore, both genes are candidates for causing skeletal muscle hypertrophy. There was unique relationship of PEG11 and PEG11AS transcript abundance in the paternal heterozygous animals that suggests a RNA interference mechanism may have a role in PEG11 gene regulation and polar overdominance in callipyge sheep

The Imprinted Retrotransposon-Like Gene PEG11 (RTL1) Is Expressed as a Full-Length Protein in Skeletal Muscle from Callipyge Sheep

peer-reviewedMembers of the Ty3-Gypsy retrotransposon family are rare in mammalian genomes despite their abundance in invertebrates and some vertebrates. These elements contain a gag-pol-like structure characteristic of retroviruses but have lost their ability to retrotranspose into the mammalian genome and are thought to be inactive relics of ancient retrotransposition events. One of these retrotransposon-like elements, PEG11 (also called RTL1) is located at the distal end of ovine chromosome 18 within an imprinted gene cluster that is highly conserved in placental mammals. The region contains several conserved imprinted genes including BEGAIN, DLK1, DAT, GTL2 (MEG3), PEG11 (RTL1), PEG11as, MEG8, MIRG and DIO3. An intergenic point mutation between DLK1 and GTL2 causes muscle hypertrophy in callipyge sheep and is associated with large changes in expression of the genes linked in cis between DLK1 and MEG8. It has been suggested that over-expression of DLK1 is the effector of the callipyge phenotype; however, PEG11 gene expression is also strongly correlated with the emergence of the muscling phenotype as a function of genotype, muscle type and developmental stage. To date, there has been no direct evidence that PEG11 encodes a protein, especially as its anti-sense transcript (PEG11as) contains six miRNA that cause cleavage of the PEG11 transcript. Using immunological and mass spectrometry approaches we have directly identified the full-length PEG11 protein from postnatal nuclear preparations of callipyge skeletal muscle and conclude that its over-expression may be involved in inducing muscle hypertrophy. The developmental expression pattern of the PEG11 gene is consistent with the callipyge mutation causing recapitulation of the normal fetal-like gene expression program during postnatal development. Analysis of the PEG11 sequence indicates strong conservation of the regions encoding the antisense microRNA and in at least two cases these correspond with structural or functional domains of the protein suggesting co-evolution of the sense and antisense genes

Walking and the social life of solar charging in rural Africa

We consider practices that sustain social and physical environments beyond those dominating sustainable HCI discourse. We describe links between walking, sociality, and using resources in a case study of community-based, solar, cellphone charging in villages in South Africa’s Eastern Cape. Like 360 million rural Africans, inhabitants of these villages are poor and, like 25% and 92% of the world, respectively, do not have domestic electricity or own motor vehicles. We describe nine practices in using the charging stations we deployed. We recorded 700 people using the stations, over a year, some regularly. We suggest that the way we frame practices limits insights about them, and consider various routines in using and sharing local resources to discover relations that might also feature in charging. Specifically, walking interconnects routines in using, storing, sharing and sustaining resources, and contributes to knowing, feeling, wanting and avoiding as well as to different aspects of sociality, social order and perspectives on sustainability. Along the way, bodies acquire literacies that make certain relationalities legible. Our study shows we cannot assert what sustainable practice means a priori and, further, that detaching practices from bodies and their paths limits solutions, at least in rural Africa. Thus, we advocate a more “alongly” integrated approach to data about practices.Web of Scienc

Megakaryocytes Enhance Mesenchymal Stromal Cells Proliferation and Inhibit Differentiation

Megakaryocytes (MKs) can induce proliferation of calvarial osteoblasts [Ciovacco et al., 2009], but this same phenomenon has not been reported for bone marrow stromal populations from long bones. Bone marrow contains several types of progenitor cells which can be induced to differentiate into multiple cell types. Herein, we examined mesenchymal stromal cell proliferation and osteoblastic differentiation when rabbit or mouse MK were cultured with i) rabbit bone marrow stromal cells, ii) rabbit dental pulp stromal cells, or iii) mouse bone marrow stromal cells. Our results demonstrated that rabbit and mouse stromal cells co-cultured with rabbit MK or mouse MK, have significant increases in proliferation on day 7 by 52%, 46%, and 24%, respectively, compared to cultures without MK. Conversely, alkaline phosphatase (ALP) activity was lower at various time points in these cells when cultures contain MK. Similarly, calcium deposition observed at day 14 rabbit bone marrow and dental pulp stromal cells and day 21 mouse bone marrow stromal cells was 63%, 69%, and 30% lower respectively, when co-cultured with MK. Gene expression studies reveal transcriptional changes broadly consistent with increased proliferation and decreased differentiation. Transcript levels of c-fos (associated with cell proliferation) trended higher after 3, 7, and 14 days in culture. Also, expression of alkaline phosphatase, osteonectin, osterix, and osteopontin, which are markers for osteoblast differentiation, showed MK-induced decreases in a cell type and time dependent manner. Taken together, these data suggest that MK play a role in stromal cell proliferation and differentiation, from multiple sites/locations in multiple species

Public and Private Education: Conceptualizing the Distinction

Common wisdom and public discourse seem to suggest that there are two types of schools, private and public. Policy debates, media outlets, and comparisons of outcomes on standardized tests and interscholastic athletic competitions make use of the distinction. This essay argues that while such a distinction can be helpful, it also tends to obscure differences in the social organization of schools. Employing a sociological analysis and providing a historical overview of educational developments, the authors focus on centralization versus decentralization of school controls and discuss the ramifications of a broad versus a narrow market niche for schools

Beyond “yesterday’s tomorrow”: future-focused mobile interaction design by and for emergent users

Mobile and ubiquitous computing researchers have long envisioned future worlds for users in developed regions. Steered by such visions, they have innovated devices and services exploring the value of alternative propositions with and for individuals, groups and communities. Meanwhile, such radical and long-term explorations are uncommon for what have been termed emergent users; users, that is, for whom advanced technologies are just within grasp. Rather, a driving assumption is that today’s high-end mobile technologies will “trickle down” to these user groups in due course. In this paper, we open the debate about what mobile technologies might be like if emergent users were directly involved in creating their visions for the future 5–10 years from now. To do this, we report on a set of envisioning workshops in India, South Africa and Kenya that provide a roadmap for valued, effective devices and services for these regions in the next decade. © 2016, The Author(s)

Biological response to pre-mineralized starch based scaffolds for bone tissue engineering

It is known that calcium-phosphate (Ca-P) coatings are able not only to improve the bone bonding behaviour of polymeric materials, but at the same time play a positive role on enhancing cell adhesion and inducing the differentiation of osteoprogenitor cells. Recently an innovative biomimetic methodology, in which a sodium silicate gel was used as a nucleative agent, was proposed as an alternative to the currently available biomimetic coating methodologies. This methodology is especially adequate for coating biodegradable porous scaffolds. In the present work we evaluated the influence of the referred to treatment on the mechanical properties of 50/50 (wt%) blend of corn starch/ethylene-vinyl alcohol (SEVA-C) based scaffolds. These Ca-P coated scaffolds presented a compressive modulus of 224.6 ± 20.6 and a compressive strength of 24.2 ± 2.20. Cytotoxicity evaluation was performed according ISO/EN 10993 part 5 guidelines and showed that the biomimetic treatment did not have any deleterious effect on L929 cells and did not inhibit cell growth. Direct contact assays were done by using a cell line of human osteoblast like cells (SaOS-2). 3 × 105 cells were seeded per scaffold and allowed to grow for two weeks at 37 ◦C in a humidified atmosphere containing 5% CO2. Total protein quantification and scanning electron microscopy (SEM) observation showed that cells were able to grow in the pre-mineralized scaffolds. Furthermore cell viability assays (MTS test) also show that cells remain viable after two weeks in culture. Finally, protein expression studies showed that after two weeks osteopontin and collagen type I were being expressed by SaOS-2 cells seeded on the pre-mineralized scaffolds. Moreover, alkaline phosphatase (ALP) activity was higher in the supernatants collected from the pre-mineralized samples, when compared to the control samples (non Ca-P coated). This may indicate that a faster mineralization of the ECM produced on the pre-mineralized samples was occurring. Consequently, biomimetic pre-mineralization of starch based scaffolds can be a useful route for applying these materials on bone tissue engineering

A cycle of brain gain, waste and drain - a qualitative study of non-EU migrant doctors in Ireland.

BACKGROUND: Ireland is heavily reliant on non-EU migrant health workers to staff its health system. Shortages of locally trained health workers and policies which facilitate health worker migration have contributed to this trend. This paper provides insight into the experiences of non-EU migrant doctors in the Irish health workforce. METHOD: In-depth interviews were conducted with 37 non-EU migrant doctors in Ireland in 2011/2012. RESULTS: Respondents believed they had been recruited to fill junior hospital doctor 'service' posts. These posts are unpopular with locally trained doctors due to the limited career progression they provide. Respondents felt that their hopes for career progression and postgraduate training in Ireland had gone unrealised and that they were becoming de-skilled. As a result, most respondents were actively considering onward migration from Ireland. DISCUSSION & CONCLUSIONS: Failure to align the expectations of non-EU migrant doctors with the requirements of the health system has resulted in considerable frustration and a cycle of brain gain, waste and drain. The underlying reasons for high mobility into and out of the Irish medical workforce must be addressed if this cycle is to be broken. The heavy reliance on non-EU migrant doctors to staff the medical workforce has distracted from the underlying workforce challenges facing the Irish medical workforce

Institutional assessment as an instrument of rationalization back to the school as a formal organisation

O papel central da avaliação, da avaliação institucional e dos processos de garantia da qualidade de escolas e universidades nas políticas educacionais é objeto de discussão, também considerando a reforma do Estado. As teorias da nova gestão pública e as perspectivas gestionárias são consideradas como algumas das principais fontes de inspiração e de legitimação no contexto dominante de uma educação contábil. Dados empíricos preliminares resultantes do processo de avaliação externa de escolas básicas e secundárias portuguesas são apresentados e interpretados de acordo com os principais conceitos e representações organizacionais de escola presentes nos relatórios externos. Examinando algumas das imagens e dos significados de escola, cultura de escola, autonomia, objetivos, liderança e eficácia presentes nos relatórios de avaliação, o autor releva a importância das imagens formais, racionais e burocráticas de escolas. Várias questões de investigação são apresentadas tendo por base aquilo a que o autor chama o processo da hiperburocratização das organizações educativas. Algumas dimensões do conceito de burocracia de Max Weber são revisitadas, em articulação com perspectivas neocientíficas de garantia da qualidade e com as tecnologias da informação e comunicação. O autor sugere que maior relevância deve ser atribuída aos modelos formais e racionais de interpretação das organizações educativas, pois os processos de avaliação e de garantia da qualidade estão a contribuir para a formalização de escolas e universidades e para a intensificação do seu processo de racionalização, isto é, para a emergência de uma imagem analítica das escolas como hiperburocracias.The central role of evaluation, institutional assessment and quality assurance processes of schools and universities in education policy is object of discussion also considering the reform of the state. New Public Management theories and managerialist perspectives are considered some of the main sources of inspiration and legitimation in the dominant context of an audit education. Preliminary empirical data from external assessment of Portuguese primary and secondary schools are introduced and interpreted according to the main concepts and organizational representations of school found in external reports. Examining some of the central organizational images and meanings of school, school culture, autonomy, goals, leadership and effectiveness included in the external reviews, the author stresses the importance of formal, rational and bureaucratic images of schools. Several new research questions are presented for further inquiry based on the hypothesis of what it is called by the author the process of hyperbureaucratization of educational organizations. Some of the main dimensions of the concept of bureaucracy as presented by Max Weber are revisited in close relation with neo-scientific approaches of quality assurance and taking in consideration the use of information and communication technologies. Accordingly the author suggests that much more importance must be given to formal and rational models of interpreting educational organizations because assessment and quality assurance procedures are contributing to the formalization of schools and universities and to the intensification of their process of rationalization, i. e., to the emergence of an analytic image of schools as hyperbureaucracies.(undefined