2,495 research outputs found
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The effects of visual and acoustic deterrents to prevent the upstream movement of Asian carps
Proposal of a novel design for linear superconducting motor using 2G tape stacks
This paper presents a new design for a su-
perconducting linear motor (SLM). This SLM uses stacks
of second-generation (2G) superconducting tapes, which
are responsible for replacing yttrium barium copper oxide
bulks. The proposed SLM may operate as a synchronous
motor or as a hysteresis motor, depending on the load
force magnitude. A small-scale linear machine prototype
with 2G stacks was constructed and tested to investigate
the proposed SLM topology. The stator traveling magnetic
field wave was represented by several Nd-Fe-B permanent
magnets. A relative movement was produced between the
stator and the stack, and the force was measured along the
displacement. This system was also simulated by the finite
element method, in order to calculate the induced currents
in the stack and determine the electromagnetic force. The
H-formulation was used to solve the problem, and a power
law relation was applied to take into account the intrin-
sically nonlinearity of the superconductor. The simulated
and measured results were in accordance. Simulated re-
sults were extrapolated, proving to be an interesting tool to
scale up the motor in future projects. The proposed motor
presented an estimated force density of almost 500 N/kg,
which is much higher than any linear motor.This work was supported in part by the following agencies: CNPq/CAPES/INERGE, CNPq—Ci ˆ encias sem Fronteiras, FAPERJ, Catalan Government 2014- SGR-753, CONSOLIDER Excellence Network MAT2014-56063-C2-1-R and MAT2015-68994-REDC, Eurofusion EU COST ACTIONS MP1201/ MP1014/PPPT-WPMAG 2014, EUROTAPES FP7-NMP-Large-2011- 280432, FORTISSIMO FP7-2013-ICT-609029, and Spanish Govern- ment Agencies—Severo Ochoa Programme Centres of Excellence in R&D. (Corresponding author: Guilherme G. Sotelo.
Antifreeze Proteins in the Primary Urine of Larvae of the Beetle \u3cem\u3eDendroides canadensis\u3c/em\u3e
To avoid freezing while overwintering beneath the bark of fallen trees, Dendroides canadensis (Coleoptera: Pyrochroidae) larvae produce a family of antifreeze proteins (DAFPs) that are transcribed in specific tissues and have specific compartmental fates. DAFPs and associated thermal hysteresis activity (THA) have been shown previously in hemolymph and midgut fluid, but the presence of DAFPs has not been explored in primary urine, a potentially important site that can contain endogenous ice-nucleating compounds that could induce freezing. A maximum mean THA of 2.65±0.33°C was observed in primary urine of winter-collected D. canadensis larvae. THA in primary urine increased significantly through autumn, peaked in the winter and decreased through spring to levels of 0.2–0.3°C in summer, in a pattern similar to that of hemolymph and midgut fluid. THA was also found in hindgut fluid and excreted rectal fluid, suggesting that these larvae not only concentrate AFPs in the hindgut, but also excrete AFPs from the rectal cavity. Based on dafp transcripts isolated from Malpighian tubule epithelia, cDNAs were cloned and sequenced, identifying the presence of transcripts encoding 24 DAFP isoforms. Six of these Malpighian tubule DAFPs were known previously, but 18 are new. We also provide functional evidence that DAFPs can inhibit ice nucleators present in insect primary urine. This is potentially critical because D. canadensis larvae die if frozen, and therefore ice formation in any body fluid, including the urine, would be lethal
A novel technique for selective NF-kappa B inhibition in Kupffer cells: contrary effects in fulminant hepatitis and ischaemia-reperfusion.
Background and aims: The transcription factor nuclear
factor kappa B (NF-kB) has risen as a promising target for
anti-inflammatory therapeutics. In the liver, however, NFkB
inhibition mediates both damaging and protective
effects. The outcome is deemed to depend on the liver
cell type addressed. Recent gene knock-out studies
focused on the role of NF-kB in hepatocytes, whereas the
role of NF-kB in Kupffer cells has not yet been
investigated in vivo. Here we present a novel approach,
which may be suitable for clinical application, to
selectively target NF-kB in Kupffer cells and analyse the
effects in experimental models of liver injury.
Methods: NF-kB inhibiting decoy oligodeoxynucleotides
were loaded upon gelatin nanoparticles (D-NPs) and their
in vivo distribution was determined by confocal microscopy.
Liver damage, NF-kB activity, cytokine levels and
apoptotic protein expression were evaluated after
lipopolysaccharide (LPS), D-galactosamine (GalN)/LPS, or
concanavalin A (ConA) challenge and partial warm
ischaemia and subsequent reperfusion, respectively.
Results: D-NPs were selectively taken up by Kupffer cells
and inhibited NF-kB activation. Inhibition of NF-kB in
Kupffer cells improved survival and reduced liver injury
after GalN/LPS as well as after ConA challenge. While
anti-apoptotic protein expression in liver tissue was not
reduced, pro-apoptotic players such as cJun N-terminal
kinase (JNK) were inhibited. In contrast, selective
inhibition of NF-kB augmented reperfusion injury.
Conclusions: NF-kB inhibiting decoy oligodeoxynucleotide-
loaded gelatin nanoparticles is a novel tool to
selectively inhibit NF-kB activation in Kupffer cells in vivo.
Thus, liver injury can be reduced in experimental fulminant
hepatitis, but increased at ischaemia–reperfusion
Optimization of the Superconducting Linear Magnetic Bearing of a Maglev Vehicle
Considering the need for cost/performance prediction and optimization of
superconducting maglev vehicles, we develop and validate here a 3D finite
element model to simulate superconducting linear magnetic bearings. Then we
reduce the 3D model to a 2D model in order to decrease the computing time. This
allows us to perform in a reasonable time a stochastic optimization considering
the superconductor properties and the vehicle operation. We look for the
permanent magnet guideway geometry that minimizes the cost and maximizes the
lateral force during a displacement sequence, with a constraint on the minimum
levitation force. The displacement sequence reproduces a regular maglev vehicle
operation with both vertical and lateral movements. For the sake of comparison,
our reference is the SupraTrans prototype bearing. The results of the
optimization suggest that the bearing cost could be substantially reduced,
while keeping the same performances as the initial design. Alternatively, the
performances could be significantly improved for the same original cost
Fundamentals, topologies and optimization methods of saturated iron core fault current limiter
The energy transition is a necessity to satisfy the consumption and impact of humanity on the environment. Therefore, to fulfill this demand, renewable energies and microgrids have been developed.
Consequently, fault current levels have overcome the circuit breaker capacity in many substations over the years. Then, the development of the fault current limiters has become a potential solution to solve this problem. The literature has presented several topologies over the past decades. The saturated iron-core fault current limiter (SIC-SFCL) has exhibited promising results since this topology is tested in the distribution and transmission system substation. Thus, enforcements to increase the maturity of this equipment have been developed in different areas, for example, design, applied superconductor materials, and optimization models of the SIC-SFCL. This article has presented the fundamental concept of this equipment. Beyond that, the principal topologies have been discussed. The
article has delivered further information about the main parts that comprise this equipment. Also, the authors have introduced different characteristics which affect the recovery times of this device. The
authors have discussed the optimization methods applied to this equipment and after the conclusion is presented
Perceived Influence and Response of River Users to Invasive Bighead and Silver Carp in the Illinois River
Two United States federally injurious fishes, bighead(Hypophthalmichthys nobilis)and silver carp(H. molitrix),are established in the Mississippi River Basinand have the potential tocolonize the Laurentian Great Lakes. Given this imminentthreat, a critical need for stakeholders is an understanding ofthe potential social influences of this invasion oncommunities that rely upon the ecosystems bighead and silvercarp now inhabit; influences so far unstudied. Using intercept surveys (n= 469), we tested forthe potential social influencesof bighead and silvercarp in four river communities;three in which they haveestablishedpopulations(test, Illinois River, Illinois) and one in which they have not(control, Mississippi River, Iowa). Reported principal differences between test and control sites were observed for recreational fishing, aestheticappreciation of the river, and experience with bighead and silvercarp. Our exploratory results indicate that bighead and silvercarp may have a negative influence on river usage.Illinois Natural History Surveyunpublishednot peer reviewedOpe
X-Irradiation-Induced Disorganization of Cytoskeletal Filaments and Cell Contacts in HT29 Cells
Organization of cytoskeleton and cell contacts were studied by immunochemistry and electron microscopy in confluent HT29 cultured cells following exposure to 0.5 and 1.0 Gy doses of X-ray. Microtubules were resistant to irradiation, whereas, the actin and intermediate filaments disrupted rapidly following the treatment and their components appeared as clumps of actin and cytokeratin aggregates in the cytoplasm as demonstrated by immunochemistry. Loss of cell contacts and decrease in the number of desmosomes was also characteristic of irradiated cells. Electron microscopy revealed intact desmosomes in control cells and abnormal desmosomes in the irradiated samples characterized by the absence of tonofilaments. The perinuclear filament network and cortical filaments were well detectable by electron microscopy. Under the effect of irradiation, the perinuclear filaments almost disappeared and, at the same time, small bundles of filaments were formed irregularly in the cytoplasm associated with amorphous material
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Has River use in the Mississippi River Basin changed Following the Invasion of Asian Carp?
Abstract
Invasive bighead (Hypophthalmichthys nobilis) and silver carp (H. molitrix) are two federally injurious fishes, commonly referred to as Asian carp, found in the Mississippi River Basin. We hypothesized that silver carp, in particular, may negatively influence river users due to their tendency to leap from the water when startled. We tested whether Asian carp have influenced stakeholder use in a low fish density Mississippi River city and three high fish density cities of the Illinois River between June 2010 and July 2011 using intercept surveys. Our response rate was 39 %. Our results suggest that most respondents use these rivers for recreational purposes. Boating, swimming, and aesthetic uses of the Illinois River changed between 2010 and 2011. Nearly three quarters of Illinois River town users who have observed an Asian carp jump have been hit by one. Our findings may help susceptible river towns prepare for social, cultural, and economic changes due to these invasive fishes
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