EFFECTS OF DIVERSE VARIABLES ON RESISTIVITY, RHEOLOGY, AND NETWORK VISUALIZATION OF ELECTRICALLY CONDUCTIVE EPOXY-CNT COMPOSITES

The addition of high-aspect ratio nanometric conductive fillers (i.e., carbon nanotubes [CNTs]) to an epoxy matrix has been shown to improve electrical conductivity by many orders of magnitude. These nanocomposites, well-suited for electrostatic dissipation and electromagnetic interference applications, are of intense interest to the aerospace industry where epoxy resins are already widely employed. Future adoption and commercial production efforts are limited by a lack of understanding of how electrical and rheological properties of uncured mixtures relate to the finished composite, how they change throughout the epoxy curing process, or how these materials are affected by extreme operating environments. To bridge these gaps, the viscosity and electrical properties of uncured mixtures were characterized and correlated to cured values, potentially allowing for quality control at a point in the production process where remediation is possible. Rare-earth oxide nanoparticles, europium-doped yttria, were synthesized into CNT walls, enhancing the contrast of the conductive network in scanning electron microscopy and micro-computed tomography while also granting deep-UV fluorescence. Lastly, in-situ electrical measurements of an epoxy-CNT composite were conducted under simulated low-earth orbit conditions with instantaneous decreases in resistivity as large as 60% being documented.DOD SpaceLieutenant Commander, United States NavyApproved for public release. Distribution is unlimited

An IPMC-Enabled Bio-Inspired bending/twisting Fin for Underwater Applications

This paper discusses the design, fabrication, and characterization of an ionic polymer–metal composite (IPMC) actuator-based bio-inspired active fin capable of bending and twisting motion. It is pointed out that IPMC strip actuators are used in the simple cantilever configuration to create simple bending (flapping-like) motion for propulsion in underwater autonomous systems. However, the resulting motion is a simple 1D bending and performance is rather limited. To enable more complex deformation, such as the flapping (pitch and heaving) motion of real pectoral and caudal fish fins, a new approach which involves molding or integrating IPMC actuators into a soft boot material to create an active control surface (called a \u27fin\u27) is presented. The fin can be used to realize complex deformation depending on the orientation and placement of the actuators. In contrast to previously created IPMCs with patterned electrodes for the same purpose, the proposed design avoids (1) the more expensive process of electroless plating platinum all throughout the surface of the actuator and (2) the need for specially patterning the electrodes. Therefore, standard shaped IPMC actuators such as those with rectangular dimensions with varying thicknesses can be used. One unique advantage of the proposed structural design is that custom shaped fins and control surfaces can be easily created without special materials processing. The molding process is cost effective and does not require functionalizing or \u27activating\u27 the boot material similar to creating IPMCs. For a prototype fin (90 mm wide × 60 mm long× 1.5 mm thick), the measured maximum tip displacement was approximately 44 mm and the twist angle of the fin exceeded 10°. Lift and drag measurements in water where the prototype fin with an airfoil profile was dragged through water at a velocity of 21 cm s−1 showed that the lift and drag forces can be affected by controlling the IPMCs embedded into the fin structure. These results suggest that such IPMC-enabled fin designs can be used for developing active propeller blades or control surfaces on underwater vehicles

Winter Sighting of Beluga Whales (Delphinapterus leucas) in Yakutat-Disenchantment Bay, Alaska

On 19 February 1997, we made the first documented winter sighting of beluga whales in Yakutat-Disenchantment Bay, Alaska. We estimated that 10 individuals were swimming in ice-free, turbid water near the Hubbard Glacier. The sporadic record of belugas in the bay suggests they may be occasional visitors from the Cook Inlet population.Le 19 février 1997, nous avons pour la première fois enregistré la présence de bélougas en hiver dans la baie alaskienne de Yakutat-Disenchantment. On a estimé à 10 le nombre d'individus qui nageaient dans l'eau turbide libre de glace près du glacier Hubbard. La présence sporadique des bélougas dans la baie suggère qu'ils pourraient être des visiteurs occasionnels venant de la population du détroit de Cook

A community study of the effect of particulate matter on blood measures of inflammation and thrombosis in an elderly population

BACKGROUND: The mechanism behind the triggering effect of fine particulate matter (PM) air pollution on cardiovascular events remains elusive. We postulated that elevated levels of PM would be associated with increased blood levels of inflammatory and thrombotic markers in elderly individuals. We also hypothesized that elevated PM would increase levels of cytokines in individuals with heart disease. METHODS: We measured these blood markers in 47 elderly individuals with (23) and without (16 COPD and 8 healthy) cardiovascular disease (CVD) on 2 or 3 mornings over a 5 or 10-day period between February 2000 and March 2002. Blood measures were paired with residence level outdoor PM measured by nephelometry. Analyses determined the within-individual effect of 24-hour averaged outdoor PM on blood measures. RESULTS: Analyses found no statistically significant effect of a same day 10 ug/m(3 )increase in fine PM on log transformed levels of CRP 1.21 fold-rise [95% CI: 0.86, 1.70], fibrinogen 1.02 fold-rise [95% CI: 0.98, 1.06], or D-dimer 1.02 fold-rise [95% CI: 0.88, 1.17] in individuals with CVD. One-day lagged analyses in the CVD subgroup found similar null results. These same models found no change in these blood markers at the same-day or 1-day lag in the group without CVD. In 21 individuals with CVD, a 10 μg/m(3 )increase in same-day PM was associated with a 1.3 fold-rise [95% CI: 1.1, 1.7] in the level of monocyte chemoattractant protein-1. CONCLUSION: We did not find consistent effects of low ambient levels of PM on blood measures of inflammation or thrombosis in elderly individuals

Molecular characterisation of the first New Delhi metallo-β-lactamase 1-producing Acinetobacter baumannii from Tanzania

Background We aimed to characterise the genetic determinants and context of two meropenem-resistant clinical isolates of Acinetobacter baumannii isolated from children hospitalised with bloodstream infections in Dar es Salaam, Tanzania. Methods Antimicrobial susceptibility was determined by disc diffusion E-test and broth microdilution. Genomes were completed using a hybrid assembly of Illumina and Oxford Nanopore Technologies sequencing reads and characterisation of the genetic context of resistance genes, multi-locus sequence types (ST) and phylogenetic analysis were determined bioinformatically. Results Twelve Acinetobacter baumannii were isolated from 2226 blood cultures and two of which were meropenem resistant. The two meropenem resistant isolates, belonging to distinct STs; ST374 and ST239, were found to harbour blaNDM-1, which was chromosomally located in isolate DT0544 and plasmid located in isolate DT01139. The genetic environment of blaNDM- 1 shows the association of insertion sequence ISAba125 with blaNDM-1 in both isolates. Both isolates also harboured genes conferring resistance to other β-lactams, aminoglycosides and cotrimoxazole. Conclusions This is the first report of NDM-1 producing isolates of A. baumannii from Tanzania. The genetic context of the blaNDM-1 provides further evidence of the importance of ISAba125 in 44 the spread of blaNDM-1 in A. baumannii. Local surveillance should be strengthened to keep clinicians updated on the incidence of these and other multidrug-resistant and difficult-to- treat bacteria. Accession numbers: The chromosomal and plasmid sequences of DT0544 and DT01139 were submitted to GenBank with accession numbers PRJNA679703 and PRJNA679704, respectively

A quantum Monte Carlo study of the one-dimensional ionic Hubbard model

Quantum Monte Carlo methods are used to study a quantum phase transition in a 1D Hubbard model with a staggered ionic potential (D). Using recently formulated methods, the electronic polarization and localization are determined directly from the correlated ground state wavefunction and compared to results of previous work using exact diagonalization and Hartree-Fock. We find that the model undergoes a thermodynamic transition from a band insulator (BI) to a broken-symmetry bond ordered (BO) phase as the ratio of U/D is increased. Since it is known that at D = 0 the usual Hubbard model is a Mott insulator (MI) with no long-range order, we have searched for a second transition to this state by (i) increasing U at fixed ionic potential (D) and (ii) decreasing D at fixed U. We find no transition from the BO to MI state, and we propose that the MI state in 1D is unstable to bond ordering under the addition of any finite ionic potential. In real 1D systems the symmetric MI phase is never stable and the transition is from a symmetric BI phase to a dimerized BO phase, with a metallic point at the transition

Visuospatial Functioning In The Primary Progressive Aphasias

Objectives: The aim of this study was to identify whether the three main primary progressive aphasia (PPA) variants would show differential profiles on measures of visuospatial cognition. We hypothesized that the logopenic variant would have the most difficulty across tasks requiring visuospatial and visual memory abilities. Methods: PPA patients (n = 156), diagnosed using current criteria, and controls were tested on a battery of tests tapping different aspects of visuospatial cognition. We compared the groups on an overall visuospatial factor; construction, immediate recall, delayed recall, and executive functioning composites; and on individual tests. Cross-sectional and longitudinal comparisons were made, adjusted for disease severity, age, and education. Results: The logopenic variant had significantly lower scores on the visuospatial factor and the most impaired scores on all composites. The nonfluent variant had significant difficulty on all visuospatial composites except the delayed recall, which differentiated them from the logopenic variant. In contrast, the semantic variants performed poorly only on delayed recall of visual information. The logopenic and nonfluent variants showed decline in figure copying performance over time, whereas in the semantic variant, this skill was remarkably preserved. Conclusions: This extensive examination of performance on visuospatial tasks in the PPA variants solidifies some previous findings, for example, delayed recall of visual stimuli adds value in differential diagnosis between logopenic variant PPA and nonfluent variant PPA variants, and illuminates the possibility of common mechanisms that underlie both linguistic and non-linguistic deficits in the variants. Furthermore, this is the first study that has investigated visuospatial functioning over time in the PPA variants

Desacetyl-α-melanocyte stimulating hormone and α-melanocyte stimulating hormone are required to regulate energy balance.

OBJECTIVE: Regulation of energy balance depends on pro-opiomelanocortin (POMC)-derived peptides and melanocortin-4 receptor (MC4R). Alpha-melanocyte stimulating hormone (α-MSH) is the predicted natural POMC-derived peptide that regulates energy balance. Desacetyl-α-MSH, the precursor for α-MSH, is present in brain and blood. Desacetyl-α-MSH is considered to be unimportant for regulating energy balance despite being more potent (compared with α-MSH) at activating the appetite-regulating MC4R in vitro. Thus, the physiological role for desacetyl-α-MSH is still unclear. METHODS: We created a novel mouse model to determine whether desacetyl-α-MSH plays a role in regulating energy balance. We engineered a knock in targeted QKQR mutation in the POMC protein cleavage site that blocks the production of both desacetyl-α-MSH and α-MSH from adrenocorticotropin (ACTH1-39). RESULTS: The mutant ACTH1-39 (ACTHQKQR) functions similar to native ACTH1-39 (ACTHKKRR) at the melanocortin 2 receptor (MC2R) in vivo and MC4R in vitro. Male and female homozygous mutant ACTH1-39 (Pomctm1/tm1) mice develop the characteristic melanocortin obesity phenotype. Replacement of either desacetyl-α-MSH or α-MSH over 14 days into Pomctm1/tm1 mouse brain significantly reverses excess body weight and fat mass gained compared to wild type (WT) (Pomcwt/wt) mice. Here, we identify both desacetyl-α-MSH and α-MSH peptides as regulators of energy balance and highlight a previously unappreciated physiological role for desacetyl-α-MSH. CONCLUSIONS: Based on these data we propose that there is potential to exploit the naturally occurring POMC-derived peptides to treat obesity but this relies on first understanding the specific function(s) for desacetyl-α-MSH and α-MSH

FusionSeq: a modular framework for finding gene fusions by analyzing paired-end RNA-sequencing data

We have developed FusionSeq to identify fusion transcripts from paired-end RNA-sequencing. FusionSeq includes filters to remove spurious candidate fusions with artifacts, such as misalignment or random pairing of transcript fragments, and it ranks candidates according to several statistics. It also has a module to identify exact sequences at breakpoint junctions. FusionSeq detected known and novel fusions in a specially sequenced calibration data set, including eight cancers with and without known rearrangements

Amplified melt and flow of the Greenland ice sheet driven by late-summer cyclonic rainfall

Intense rainfall events significantly affect Alpine and Alaskan glaciers through enhanced melting, ice-flow acceleration and subglacial sediment erosion, yet their impact on the Greenland ice sheet has not been assessed. Here we present measurements of ice velocity, subglacial water pressure and meteorological variables from the western margin of the Greenland ice sheet during a week of warm, wet cyclonic weather in late August and early September 2011. We find that extreme surface runoff from melt and rainfall led to a widespread acceleration in ice flow that extended 140 km into the ice-sheet interior. We suggest that the late-season timing was critical in promoting rapid runoff across an extensive bare ice surface that overwhelmed a subglacial hydrological system in transition to a less-efficient winter mode. Reanalysis data reveal that similar cyclonic weather conditions prevailed across southern and western Greenland during this time, and we observe a corresponding ice-flow response at all land- and marine-terminating glaciers in these regions for which data are available. Given that the advection of warm, moist air masses and rainfall over Greenland is expected to become more frequent in the coming decades, our findings portend a previously unforeseen vulnerability of the Greenland ice sheet to climate change