60 research outputs found
Adsorption and binding dynamics of graphene-supported phospholipid membranes using the QCM-D technique
We report on the adsorption dynamics of phospholipid membranes on
graphene-coated substrates using the quartz crystal microbalance with
dissipation monitoring (QCM-D) technique. We compare the lipid vescle
interaction and membranne formation on gold and silicon dioxide QCM crystal
surfaces with their graphene oxide (GO) and reduced (r)GO coated counterparts,
and report on the different lipid structures obtained. We establish graphene
derivative coatings as support surfaces with tuneable hydrophobicity for the
formation of controllable lipid structures. One structure of interest formed
are lipid monolayer membrannes which were formed on rGO, which are otherwise
challenging to produce. We also demonstrate and monitor biotin-avidin binding
on such a membranne, which will then serve as a platform for a wide range of
biosensing applications. The QCM-D technique could be extended to both
fundamental studies and applications of other covalent and non-covalent
interactions in 2-dimensional materials
Determination of lunar ilmenite abundance from remotely sensed data
Of fundamental importance in the utilization of indigenous resources for a future permanently manned lunar base is the identification and mapping of the abundance distribution of the mineral ilmenite, which is currently considered the most readily identifiable and most easily accessible source of oxygen needed for human consumables and spacecraft propellant. Solid state detector array technology now permits the use of ground based multispectral remote sensing techniques to produce maps with better than one kilometer spatial resolution and uncertainties of about two weight-percent TiO2 abundance. An empirical relationship between the weight-percent abundance of titanium dioxide and the 400/560 nm spectral ratio measured in returned lunar samples was used. Because this abundance correlation is valid only for mature lunar mare regolith, the distribution of immature mafic minerals which were found to be correlated primarily with steep slopes exposing bedrock was qualitatively mapped. The first mapping phase focused on the entire lunar nearside at 5.3 km per pixel, and on experiments with more sensitive spectral ratios. Relative spectrophotometry was employed to aid in identifying wavelengths that provide greater spectral contrast. It was found that the 400/730 nm ratio improved the abundance sensitivity by 37 percent, while the 950/730 nm ratio improved mafic mineral contrast about 100 percent. The second mapping phase utilized a large experimental CCD at 280 m per pixel to map the high titanium regions identified in the phase one mapping. The high resolution maps provide data on the small scale (500 m) variations in abundance and their relationship to morphological units
Lunar phase function effects on spectral ratios used for resource assessment
Groundbased telescopic CCD images of 36 selected locations on the moon were obtained in five 'standard' bandpasses at 12 phase angles ranging from -78 deg to +75 deg to measure phase function effects on the ratio values used to quantify the abundance of TiO2 and qualitatively indicate soil maturity. Consistent with previous studies, we find that the moon is 'bluer' at small phase angles, but that the effect on the ratio values for TiO2 abundance for the phase angles of our data is on the order of the measurement uncertainties throughout the range of abundances found in the mare. The effect is more significant as seen from orbiting spacecraft over a range of selenographic latitude. Spectral ratio images (400/560 and 400/730 nm) were used to map the abundance of TiO2 using the empirical relation found by Charlette et al from analysis of returned lunar soils. Additionally, the 950/560 and 950/730 nm image ratios were used to define the regions of mature mare soil in which the relation is valid. Although the phase function dependence on wavelength was investigated and quantified for small areas and the integrated disc, the effect specifically on TiO2 mapping was not rigorously determined. For consistency and convenience in observing the whole lunar front side, our mapping utilized images taken -15 deg less than alpha less than 15 deg when the moon was fully illuminated from earth; however, this includes the strong opposition peak
Pathosphere.org: pathogen detection and characterization through a web-based, open source informatics platform
Background
The detection of pathogens in complex sample backgrounds has been revolutionized by wide access to next-generation sequencing (NGS) platforms. However, analytical methods to support NGS platforms are not as uniformly available. Pathosphere (found at Pathosphere.org) is a cloud - based open - sourced community tool that allows for communication, collaboration and sharing of NGS analytical tools and data amongst scientists working in academia, industry and government. The architecture allows for users to upload data and run available bioinformatics pipelines without the need for onsite processing hardware or technical support.
Results
The pathogen detection capabilities hosted on Pathosphere were tested by analyzing pathogen-containing samples sequenced by NGS with both spiked human samples as well as human and zoonotic host backgrounds. Pathosphere analytical pipelines developed by Edgewood Chemical Biological Center (ECBC) identified spiked pathogens within a common sample analyzed by 454, Ion Torrent, and Illumina sequencing platforms. ECBC pipelines also correctly identified pathogens in human samples containing arenavirus in addition to animal samples containing flavivirus and coronavirus. These analytical methods were limited in the detection of sequences with limited homology to previous annotations within NCBI databases, such as parvovirus. Utilizing the pipeline-hosting adaptability of Pathosphere, the analytical suite was supplemented by analytical pipelines designed by the United States Army Medical Research Insititute of Infectious Diseases and Walter Reed Army Institute of Research (USAMRIID-WRAIR). These pipelines were implemented and detected parvovirus sequence in the sample that the ECBC iterative analysis previously failed to identify.
Conclusions
By accurately detecting pathogens in a variety of samples, this work demonstrates the utility of Pathosphere and provides a platform for utilizing, modifying and creating pipelines for a variety of NGS technologies developed to detect pathogens in complex sample backgrounds. These results serve as an exhibition for the existing pipelines and web-based interface of Pathosphere as well as the plug-in adaptability that allows for integration of newer NGS analytical software as it becomes available
Species concepts and speciation factors in cyanobacteria, with connection to the problems of diversity and classification
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The effect of mutual fund investment style on the accrual and book-to-market anomalies
This paper shows that institutional investor investment style affects the association between accruals and future returns and book-to-market ratio and future returns. Since both the accrual and book-to-market anomalies generate positive future returns to a trading strategy that is consistent with a value investment style, I predict and find that the accrual effect and the book-to-market effect are lower when the percentage of shares held by value mutual funds is high. These findings are consistent with value mutual funds mitigating mispricing. Additionally, these effects are unrelated to total or growth mutual fund ownership. I also find that changes in value mutual fund holdings are positively associated with the book-to-market ratio, consistent with value funds trading to take advantage of the book-to-market effect, while the results are inconsistent with growth funds trading to take advantage of the anomaly. These results suggest that institutional investor investment style at the fund level has an effect on the accrual and book-to-market ratio anomalies
Relationships between insomnia and sleep-disordered breathing [5] (multiple letters)
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The financial crisis and mark-to-market accounting: An analysis of cascading media rhetoric and storytelling
Purpose – The purpose of this paper is to analyze media storytelling and rhetoric surrounding the credibility of the longstanding accounting practice of mark-to-market valuation. Design/methodology/approach – The cascading storytelling model of progressive framing by the media of mark-to-market valuation was applied to story subsets of the three types of classic Aristotelian rhetorical appeals. Findings – The authors found that the media blamed the accounting profession's mark-to-market valuation practices as substantive cause of recent corporate problems and declines in market values. In addition, the rhetorical framing of mark-to-market accounting practices in the media prompted the Financial Accounting Standards Board to a rush to judgment. Research limitations/implications – The paper is limited to the analysis of the storytelling included. Different results from other sources may provide another result. Practical implications – The failure in the media to address the duality between the logos of accounting and the ethos of the media narratives exacerbated the cascading activation. Understanding this duality may provide a different lens in looking at information dissemination. This is not only relative to stakeholders in making more informed decisions but should also serve as a warning to the profession, to have more voice, to use a rhetorical strategy that can have more saliency in the public arena. Originality/value – The paper examined storytelling as interplay of retrospective narrative, the presentness of living story, and the antenarratives shaping the future of not only the unfolding economic crisis, but the future of accounting itself. In terms of rhetoric, we extended the application of pathos, ethos, and logos by examining a cascading activation theory model. This is one of the few studies of antenarratives and how through cascade rhetoric the future is shaped.Accounting, Marketing, Rhetoric, Storytelling
Precipitation kinetics in a 10.5% Cr heat resistant steel: experimental results and simulation by TC-PRISMA / DICTRA
The precipitation kinetics of secondary phases in a 10.5%Cr heat resistant steel, designed by the authors, was studied experimentally and theoretically. Experimental data of nucleation, growth and coarsening stages for M23C6 carbides, V-MX, Nb-MX and Laves phase were obtained by HRTEM-characterization on samples after tempering (780 degrees C/2 h) and isothermally aging for 1440 h and 8760 h at 650 degrees C. Theoretical studies of precipitation behavior of M23C6 and Laves phase were carried out by TC-PRISMA and complemented with DICTRA. A good fit between TC-PRISMA simulation and experimental results was obtained for M23C6 carbides considering a heterogeneous nucleation in grain boundaries, a semi-coherent interfacial energy of 0.3 J/m(2), and decreasing the atomic mobility along grain boundary in order to include the effect of B. Experiments and simulation indicate a low coarsening rate for M23C6 carbides. Furthermore, precipitation of Laves phase at 650 degrees C was simulated by TC-PRISMA considering the effect of W and Si segregation at grain boundary, prior to the beginning of the nucleation and growth processes. Therefore, thermodynamic and kinetic boundary conditions were changed purposely in TC-PRISMA. Best agreement with the experimental results was obtained for an interfacial energy of 0.6 J/m(2) and heterogeneous nucleation in grain boundary.DOCTORADO NACIONAL
21130630
project "FONDECYT de Iniciacion" from the Chilean Government
11110098
11121384
"Proyecto de insercion de capital humano avanzado" from the Chilean Government
79112035
project "FONDECYT" from the Chilean Government
1150457"
Create-Net project
H2020-MSCA-RISE/64401
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