Applications of high thermal conductivity composites to electronics and spacecraft thermal design

Recently, high thermal conductivity continuous graphite fiber reinforced metal matrix composites (MMC's) have become available that can save much weight over present methods of heat conduction. These materials have two or three times higher thermal conductivity in the fiber direction than the pure metals when compared on a thermal conductivity to weight basis. Use of these materials for heat conduction purposes can result in weight savings of from 50 to 70 percent over structural aluminum. Another significant advantage is that these materials can be used without the plumbing and testing complexities that accompany the use of liquid heat pipes. A spinoff of this research was the development of other MMC's as electronic device heat sinks. These use particulates rather than fibers and are formulated to match the coefficient of thermal expansion of electronic substrates in order to alleviate thermally induced stresses. The development of both types of these materials as viable weight saving substitutes for traditional methods of thermal control for electronics packaging and also for spacecraft thermal control applications are the subject of this report

The Social Dimensions of Economic Activity in Melanesia

The way people produce, transact, arrange and remunerate labour, distribute, accumulate, possess, and consume is shaped by their social context. Whether in Melbourne or Moresby, the economic is not a separate domain upon which social considerations impinge, but is always embedded within social structures and relationships particular to a place. This is evident in how Melanesians have engaged with cash-earning activities. Local engagements are diverse, but all have reconfigured and reinterpreted introduced ideas, practices and institutions through local practices and understandings (McCormack and Barclay 2013). This means, for instance, that although people are buying and selling, they cannot be assumed to subscribe to the same principles, or possess the same motivations, considerations and challenges as small business in Australia (Curry 2005). This In Brief points to the diverse influences on people's efforts to earn money in Melanesia, and emphasises that understanding these influences is an important starting point for development interventions aimed at improving livelihoods and cultivating entrepreneurship.AusAI

Fear and Loathing in Port Moresby: Chewing Over the Betel Nut Ban

In this In Brief, Tim Sharp discusses the recent betel nut ban in Port Moresby, and implications of this ban for the thriving betel nut economy. Hard copies of Tim's recent PhD thesis entitled "Following Buai : the highlands betel nut trade, Papua New Guinea" are available through the ANU Library.AusAI

The Formal, the Informal, and the Precarious: Making a Living in Urban Papua New Guinea

For many Papua New Guineans, the dominant accounts of 'the economy' � contained within development reports, government documents and the media � do not adequately reflect their experiences of making a living. Large-scale resource extraction, the private sector, export cash cropping and wage employment have dominated these accounts. Meanwhile, the broader economic picture has remained obscured, and the diversity of economic practices, including a flourishing 'informal' economy, has routinely been overlooked and undervalued. Addressing this gap, this paper provides some grounded examples of the diverse livelihood strategies people employ in Papua New Guinea's growing urban centres. We examine the strategies people employ to sustain themselves materially, and focus on how people acquire and recirculate money. We reveal the interconnections between a diverse range of economic activities, both formal and informal. In doing so, we complicate any clear narrative that might, for example, associate waged employment with economic security, or street selling with precarity and urban poverty. Our work is informed by observations of people's daily lives, and conversations with security guards (Stephanie Lusby), the salaried middle class (John Cox), women entrepreneurs (Ceridwen Spark), residents from the urban settlements (Michelle Rooney) and betel nut traders and vendors (Timothy Sharp). Collectively, our work takes an urban focus, yet the flows and connectivity between urban and rural, and our focus on livelihood strategies, means much of our discussion is also relevant to rural people and places. Our examples, drawn from urban centres throughout the country, each in their own way illustrate something of the diversity of economic activity in urban PNG. Our material captures the innovation and experimentation of people's responses to precarity in contemporary PNG.AusAI

Electron‐ and nuclear‐spin relaxation in an integer spin system, tris‐(acetylacetonato)Mn(iii) in solution

Expressions are derived for the intermolecular contribution to the nuclear‐spin relaxation rate in solutions containing dissolved paramagnetic ions with spin S≥1. The calculation assumes that the electron‐spin Hamiltonian is dominated by a large axial zero‐field splitting, and it accounts for effects of Zeeman interactions to first order. The expressions are used to analyze proton‐spin relaxation of the acetone solvent in solutions of tris‐(acetylacetonato)Mn(iii)/ acetone. The main objective was to measure electron‐spin relaxation times of Mn(iii), which in this complex is a high‐spin, d4 ion with integer spin S=2. Spin‐lattice relaxation measurements were conducted over a range of magnetic field strengths (0.28–1.1 T) where the zero‐field splitting is large compared to the Zeeman energy. Electron‐spin relaxation times of Mn(iii) were found to be 8±2 ps, with little dependence on temperature over the range 215–303 K and on magnetic field strength up to 1.1 T. Use of the assumption that Zeeman splittings dominate zero‐field splittings (Solomon–Bloembergen–Morgan theory) resulted in computed electron‐spin relaxation times that are too short by a factor of 3–4.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71073/2/JCPSA6-92-10-5892-1.pd

The Psychosocial Impact of Self-Reported Morning Allergy Symptoms: Findings from an Australian Internet-Based Survey

Background. Allergies can substantially impact health-related quality of life (HRQL). We investigated the psychosocial impact of morning symptoms amongst Australian adults with self-reported allergic rhinitis (AR). Method. An online survey comprising 24 questions was conducted in August 2008. Inclusion criteria were age (20–49 years) and self-reported moderate to severe symptoms of AR. Results. One thousand sixty respondents met the inclusion criteria. Amongst consumers with self-reported AR, symptoms were more severe in the morning in 597 (56%) and affected mood in 1025 (97%). Nine hundred seventy (91%) indicated that their symptoms had some impact on their day ahead and 868 (82%) reported a negative impact on relationships. Morning symptoms in particular had a substantial affect on mood for the day. HRQL impact was more pronounced in those who reported severe symptoms and in females. Discussion. Encouraging consumers with self-diagnosed AR to seek formal diagnosis and offering appropriate treatment strategies, such as those offering sustained effectiveness over 24-hours, may aid in negating the negative impact of morning symptoms

Identification of a non-mammalian leptin-like gene:characterization and expression in the tiger salamander (Ambystoma tigrinum)

Leptin is well established as a multifunctional cytokine in mammals. However, little is known about the evolution of the leptin gene in other vertebrates. A recently published set of ESTs from the tiger salamander (Ambystoma tigrinum) contains a sequence sharing 56% nucleotide sequence identity with the human leptin cDNA. To confirm that the EST is naturally expressed in the salamander, a 409 bp cDNA was amplified by RT-PCR of salamander testis and stomach mRNAs. The coding sequence of the cDNA is predicted to encode 169 amino acids, and the mature peptide to consist of 146 residues, as in mammals. Although the overall amino acid identity with mammalian leptins is only 29%, the salamander and mammalian peptides share common structural features. An intron was identified between coding exons providing evidence that the sequence is present in the salamander genome. Phylogenetic analysis showed a rate of molecular divergence consistent with the accepted view of vertebrate evolution. The pattern of tissue expression of the leptin-like cDNA differed between metamorphosed adult individuals of different sizes suggesting possible developmental regulation. Expression was most prominent in the skin and testis, but was also detected in tissues in which leptin mRNA is present in mammals, including the fat body, stomach, and muscle. The characterization of a salamander leptin-like gene provides a basis for understanding how the structure and functions of leptin have altered during the evolution of tetrapod vertebrates

Imported Asian swamp eels (Synbranchidae: Monopterus ) in North American live food markets: Potential vectors of non-native parasites

Since the 1990s, possibly earlier, large numbers of Asian swamp eels (Synbranchidae: Monopterus spp.), some wild-caught, have been imported live from various countries in Asia and sold in ethnic food markets in cities throughout the USA and parts of Canada. Such markets are the likely introduction pathway of some, perhaps most, of the five known wild populations of Asian swamp eels present in the continental United States. This paper presents results of a pilot study intended to gather baseline data on the occurrence and abundance of internal macroparasites infecting swamp eels imported from Asia to North American retail food markets. These data are important in assessing the potential role that imported swamp eels may play as possible vectors of non-native parasites. Examination of the gastrointestinal tracts and associated tissues of 19 adult-sized swamp eels—identified as M. albus “Clade C”—imported from Vietnam and present in a U.S. retail food market revealed that 18 (95%) contained macroparasites. The 394 individual parasites recovered included a mix of nematodes, acanthocephalans, cestodes, digeneans, and pentastomes. The findings raise concern because of the likelihood that some parasites infecting market swamp eels imported from Asia are themselves Asian taxa, some possibly new to North America. The ecological risk is exacerbated because swamp eels sold in food markets are occasionally retained live by customers and a few reportedly released into the wild. For comparative purposes, M. albus “Clade C” swamp eels from a non-native population in Florida (USA) were also examined and most (84%) were found to be infected with internal macroparasites. The current level of analysis does not allow us to confirm whether these are non-native parasites

Argonaute-Bound Small RNAs from Promoter-Proximal RNA Polymerase II

Argonaute (Ago) proteins mediate posttranscriptional gene repression by binding guide miRNAs to regulate targeted RNAs. To confidently assess Ago-bound small RNAs, we adapted a mouse embryonic stem cell system to express a single epitope-tagged Ago protein family member in an inducible manner. Here, we report the small RNA profile of Ago-deficient cells and show that Ago-dependent stability is a common feature of mammalian miRNAs. Using this criteria and immunopurification, we identified an Ago-dependent class of noncanonical miRNAs derived from protein-coding gene promoters, which we name transcriptional start site miRNAs (TSS-miRNAs). A subset of promoter-proximal RNA polymerase II (RNAPII) complexes produces hairpin RNAs that are processed in a DiGeorge syndrome critical region gene 8 (Dgcr8)/Drosha-independent but Dicer-dependent manner. TSS-miRNA activity is detectable from endogenous levels and following overexpression of mRNA constructs. Finally, we present evidence of differential expression and conservation in humans, suggesting important roles in gene regulation.United States. Public Health Service (grant RO1 GM34277)National Cancer Institute (U.S.) (PO1-CA42063)National Cancer Institute (U.S.) (Koch Institute Support (core) grant P30-CA14051)National Institutes of Health (U.S.). Ruth L. Kirschstein National Research Service Award (F32GM101872)National Institutes of Health (U.S.). Ruth L. Kirschstein National Research Service Award (F32CA139902

Matrigel modulates a stem cell phenotype and promotes tumor cell formation in a mantle cell lymphoma cell line

Tumors may be maintained by subpopulations of cells possessing stem cell-like properties. We evaluated the stem cell-like and tumor-forming properties of side population (SP) and CD133+/ CD44+ cells in Granta 519, a human mantle cell lymphoma cell line. The in-vitro Cobblestone Area Forming Cell (CAFC) assay, designed to detect stem and progenitor cells, revealed that SP cells contained the greatest proportion of stem cell-like cells. The addition of Matrigel to CAFC assays of SP and non-SP cells both increased their respective stem cell frequencies in comparison to those cultures without Matrigel, and additionally resulted in observed stem cell frequencies which were the same between SP and non-SP cells. Contrary, Matrigel decreased the stem cell frequencies of CD133+/CD44+ or CD133-/CD44- cells. In-vivo assays revealed tumor formation from Matrigel-mixed SP and non-SP cells, and in one instance, occurred with as few as one Matrigel-mixed SP cell. Vehicle-mixed injections of SP and non-SP tumor cells resulted in tumor formation from SP cells only. Tumor formation did not occur from Matrigel nor hyaluronan (cellular substrate for CD44-expressing cells)-mixed populations of CD133+/CD44+ or CD133-/CD44- cells. These data demonstrate that Matrigel modulates a stem cell phenotype and promotes tumor formation from SP and non-SP cells. The tumor micro-environmental niche and tumor cell to micro-environmental interactions may be important future targets for novel chemotherapeutic agent