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 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

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

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

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

Marketing the Research Missions of Academic Medical Centers: Why Messages Blurring Lines Between Clinical Care and Research Are Bad for both Business and Ethics.

Academic Medical Centers (AMCs) offer patient care and perform research. Increasingly, AMCs advertise to the public in order to garner income that can support these dual missions. In what follows, we raise concerns about the ways that advertising blurs important distinctions between them. Such blurring is detrimental to AMC efforts to fulfill critically important ethical responsibilities pertaining both to science communication and clinical research, because marketing campaigns can employ hype that weakens research integrity and contributes to therapeutic misconception and misestimation, undermining the informed consent process that is essential to the ethical conduct of research. We offer ethical analysis of common advertising practices that justify these concerns. We also suggest the need for a deliberative body convened by the Association of American Medical Colleges and others to develop a set of voluntary guidelines that AMCs can use to avoid in the future, the problems found in many current AMC advertising practices

High-intensity strength training in an older population: a preliminary study

BACKGROUND: Osteoarthritis is the most common joint disease worldwide, and it occurs mainly later in life. Many factors are associated with osteoarthritis development, including decline in muscle strength. Muscle strengthening exercises have been recognized as important approaches to osteoarthritis conservative management of the knee; however, issues related to its applicability in terms of intensity are still elusive. OBJECTIVE: Studies using high-intensity exercises have shown inconsistent results, thus the purpose of this study was to analyze the response to high-intensity strength training for muscle strength and physical function in an older healthy population, as well as their attitudes towards the strength training. METHODS: This study employed a within-subject, repeated measure, in an experimental design to assess the response to strength training for physical mobility and strength in a cohort of 10 healthy older subjects at baseline and after six weeks of intervention. RESULTS: The statistical analysis demonstrated that knee extensor isokinetic peak torque significantly improved (p < 0.05) after intervention, whereas knee flexors only showed a trend for improvement (p = 0.066). Repetition maximum tests had significant improvements for all exercises performed. There was no change in physical mobility after intervention (p = 0.163). CONCLUSION: The results of this study demonstrate that high-intensity strength training was safe and has potential value in healthy older people

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

Enabling Large Focal Plane Arrays Through Mosaic Hybridization

We have demonstrated advances in mosaic hybridization that will enable very large format far-infrared detectors. Specifically we have produced electrical detector models via mosaic hybridization yielding superconducting circuit patbs by hybridizing separately fabricated sub-units onto a single detector unit. The detector model was made on a 100mm diameter wafer while four model readout quadrant chips were made from a separate 100mm wafer. The individually fabric.ted parts were hybridized using a Suss FCI50 flip chip bonder to assemble the detector-readout stack. Once all of the hybridized readouts were in place, a single, large and thick silicon substrate was placed on the stack and attached with permanent epoxy to provide strength and a Coefficient of Thermal Expansion match to the silicon components underneath. Wirebond pads on the readout chips connect circuits to warm readout electronics; and were used to validate the successful superconducting electrical interconnection of the model mosaic-hybrid detector. This demonstration is directly scalable to 150 mm diameter wafers, enabling pixel areas over ten times the area currently available

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