1,646 research outputs found
A homopolar disc dynamo experiment with liquid metal contacts
We present experimental results of a homopolar disc dynamo constructed at
CICATA-Quer\'etaro in Mexico. The device consists of a flat, multi-arm spiral
coil which is placed above a fast-spinning metal disc and connected to the
latter by sliding liquid-metal electrical contacts. Theoretically,
self-excitation of the magnetic field is expected at the critical magnetic
Reynolds number Rm~45, which corresponds to a critical rotation rate of about
10 Hz. We measured the magnetic field above the disc and the voltage drop on
the coil for the rotation rate up to 14 Hz, at which the liquid metal started
to leak from the outer sliding contact. Instead of the steady magnetic field
predicted by the theory we detected a strongly fluctuating magnetic field with
a strength comparable to that of Earth's magnetic field which was accompanied
by similar voltage fluctuations in the coil. These fluctuations seem to be
caused by the intermittent electrical contact through the liquid metal. The
experimental results suggest that the dynamo with the actual electrical
resistance of liquid metal contacts could be excited at the rotation rate of
around 21 Hz provided that the leakage of liquid metal is prevented.Comment: 6 pages, 5 figures (to appear in Magnetohydrodynamics
HSV-1 and endogenous retroviruses as risk factors in demyelination
Herpes simplex virus type 1 (HSV-1) is a neurotropic alphaherpesvirus that can infect the peripheral and central nervous systems, and it has been implicated in demyelinating and neurodegenerative processes. Transposable elements (TEs) are DNA sequences that can move from one genomic location to another. TEs have been linked to several diseases affecting the central nervous system (CNS), including multiple sclerosis (MS), a demyelinating disease of unknown etiology influenced by genetic and environmental factors. Exogenous viral transactivators may activate certain retrotransposons or class I TEs. In this context, several herpesviruses have been linked to MS, and one of them, HSV-1, might act as a risk factor by mediating processes such as molecular mimicry, remyelination, and activity of endogenous retroviruses (ERVs). Several herpesviruses have been involved in the regulation of human ERVs (HERVs), and HSV-1 in particular can modulate HERVs in cells involved in MS pathogenesis. This review exposes current knowledge about the relationship between HSV-1 and human ERVs, focusing on their contribution as a risk factor for MS
Immunodiagnosis of Neurocysticercosis: Ways to Focus on the Challenge
Neurocysticercosis (NCC) is a disease of the central nervous system that is considered a public health problem in endemic areas. The definitive diagnosis of this disease is made using a combination of tools that include imaging of the brain and immunodiagnostic tests, but the facilities for performing them are usually not available in endemic areas. The immunodiagnosis of NCC is a useful tool that can provide important information on whether a patient is infected or not, but it presents many drawbacks as not all infected patients can be detected. These tests rely on purified or semipurified antigens that are sometimes difficult to prepare. Recent efforts have focused on the production of recombinant or synthetic antigens for the immunodiagnosis of NCC and interesting studies propose the use of new elements as nanobodies for diagnostic purposes. However, an immunodiagnostic test that can be considered as âgold standardâ has not been developed so far. The complex nature of cysticercotic disease and the simplicity of common immunological assumptions involved explain the low scores and reproducibility of immunotests in the diagnosis of NCC. Here, the most important efforts for developing an immunodiagnostic test of NCC are listed and discussed. A more punctilious strategy based on the design of panels of confirmed positive and negative samples, the use of blind tests, and a worldwide effort is proposed in order to develop an immunodiagnostic test that can provide comparable results. The identification of a set of specific and representative antigens of T. solium and a thorough compilation of the many forms of antibody response of humans to the many forms of T. solium disease are also stressed as necessary
PREVALENCIA DE PARĂSITOS GASTROINTESTINALES EN CABALLOS PURA SANGRE DE CARRERA (EQUUS CABALLUS) DURANTE EL PERIODO DE CUARENTENA 2010 EN EL HIPODROMO âLA RINCONADAâ CARACAS, VENEZUELA
650 horses (Equus caballus Linnaeus, 1758), race Thoroughbred Race, 300 male and 350 female were studied, all of two years old, from breeding centers in the central region of Venezuela by stool by McMaster flotation technique (Willis-Molloy) during the quarantine period 2010 at the Racetrack "La Rinconada" Caracas, Venezuela. Parasitological study revealed the presence of Strongyle eggs in 477 horses (73%), Parascaris equorum (Goeze, 1782) eggs in 23 (4%) and 150 (23%) were negative. The presence of strongylos remained within the range of 550-1850 HPG (Eggs per g of stool), while P. equorum was 250-600 HPG. These results suggestive an inadequate health plan and specifically to control parasites. It is possible the parasite resistance to conventional use, but this may be associated with climate changes that alter the life cycle of these parasites. In conclusion, we reported the presence of gastrointestinal parasites in Thoroughbred horses during the quarantine period at the Racetrack "La Rinconada" Caracas, Venezuela.Se realizĂł un estudio coprolĂłgico empleando la tĂ©cnica de flotaciĂłn Mc master (Willis-Molloy) a un total de 650 equinos (Equus caballus Linnaeus, 1758), raza Pura Sangre de Carrera, 300 machos y 350 hembras, todos de 2 años de edad, procedentes de centros de crĂa de la regiĂłn central de Venezuela durante el periodo de cuarentena 2010 en el HipĂłdromo âLa Rinconadaâ Caracas, Venezuela. El estudio parasitolĂłgico revelĂł la presencia de huevos de estrĂłngilos en 477 equinos (73%), huevos de Parascaris equorum (Goeze, 1782) en 23 (4%) y 150 negativos (23%). La presencia de estrĂłngilos se mantuvo por equino entre un rango de 550-1850 HPG (Huevos por g de heces), mientras que P. equorum fue para 250-600 HPG. Estos resultados parecen indicar un plan sanitario inadecuado y especĂficamente en el control de parĂĄsitos. Es posible una resistencia parasitaria a los desparasitantes de uso convencional, pero tambiĂ©n pudiera estar asociado a los cambios climĂĄticos que modifican el ciclo biolĂłgico de estos parĂĄsitos. En conclusiĂłn, se registrĂł la presencia de parĂĄsitos gastrointestinales en equinos de Pura Sangre de Carreras, durante el periodo de cuarentena en el HipĂłdromo âLa Rinconadaâ Caracas, Venezuela
Potent Virucidal Activity In Vitro of Photodynamic Therapy with Hypericum Extract as Photosensitizer and White Light against Human Coronavirus HCoV-229E
The emergent human coronavirus SARS-CoV-2 and its high infectivity rate has highlighted the strong need for new virucidal treatments. In this sense, the use of photodynamic therapy (PDT) with white light, to take advantage of the sunlight, is a potent strategy for decreasing the virulence and pathogenicity of the virus. Here, we report the virucidal effect of PDT based on Hypericum extract (HE) in combination with white light, which exhibits an inhibitory activity of the human coronavirus HCoV-229E on hepatocarcinoma Huh-7 cells. Moreover, despite continuous exposure to white light, HE has long durability, being able to maintain the prevention of viral infection. Given its potent in vitro virucidal capacity, we propose HE in combination with white light as a promising candidate to fight against SARS-CoV-2 as a virucidal compound
Interaction of PLP with GFP-MAL2 in the Human Oligodendroglial Cell Line HOG
The velocity of the nerve impulse conduction of vertebrates relies on the myelin sheath, an electrically insulating layer that surrounds axons in both the central and peripheral nervous systems, enabling saltatory conduction of the action potential. Oligodendrocytes are the myelin-producing glial cells in the central nervous system. A deeper understanding of the molecular basis of myelination and, specifically, of the transport of myelin proteins, will contribute to the search of the aetiology of many dysmyelinating and demyelinating diseases, including multiple sclerosis. Recent investigations suggest that proteolipid protein (PLP), the major myelin protein, could reach myelin sheath by an indirect transport pathway, that is, a transcytotic route via the plasma membrane of the cell body. If PLP transport relies on a transcytotic process, it is reasonable to consider that this myelin protein could be associated with MAL2, a raft protein essential for transcytosis. In this study, carried out with the human oligodendrocytic cell line HOG, we show that PLP colocalized with green fluorescent protein (GFP)-MAL2 after internalization from the plasma membrane. In addition, both immunoprecipitation and immunofluorescence assays, indicated the existence of an interaction between GFP-MAL2 and PLP. Finally, ultrastructural studies demonstrated colocalization of GFP-MAL2 and PLP in vesicles and tubulovesicular structures. Taken together, these results prove for the first time the interaction of PLP and MAL2 in oligodendrocytic cells, supporting the transcytotic model of PLP transport previously suggested
The Imaging Magnetograph eXperiment (IMaX) for the Sunrise balloon-borne solar observatory
The Imaging Magnetograph eXperiment (IMaX) is a spectropolarimeter built by
four institutions in Spain that flew on board the Sunrise balloon-borne
telesocope in June 2009 for almost six days over the Arctic Circle. As a
polarimeter IMaX uses fast polarization modulation (based on the use of two
liquid crystal retarders), real-time image accumulation, and dual beam
polarimetry to reach polarization sensitivities of 0.1%. As a spectrograph, the
instrument uses a LiNbO3 etalon in double pass and a narrow band pre-filter to
achieve a spectral resolution of 85 mAA. IMaX uses the high Zeeman sensitive
line of Fe I at 5250.2 AA and observes all four Stokes parameters at various
points inside the spectral line. This allows vector magnetograms, Dopplergrams,
and intensity frames to be produced that, after reconstruction, reach spatial
resolutions in the 0.15-0.18 arcsec range over a 50x50 arcsec FOV. Time
cadences vary between ten and 33 seconds, although the shortest one only
includes longitudinal polarimetry. The spectral line is sampled in various ways
depending on the applied observing mode, from just two points inside the line
to 11 of them. All observing modes include one extra wavelength point in the
nearby continuum. Gauss equivalent sensitivities are four Gauss for
longitudinal fields and 80 Gauss for transverse fields per wavelength sample.
The LOS velocities are estimated with statistical errors of the order of 5-40
m/s. The design, calibration and integration phases of the instrument, together
with the implemented data reduction scheme are described in some detail.Comment: 17 figure
Regulation of Intestinal Immune Response by Selective Removal of the Anterior, Posterior, or Entire Pituitary Gland in Trichinella spiralis Infected Golden Hamsters
The influence of anterior pituitary hormones on the gastrointestinal tract of humans and animals has been previously reported. Hypophysectomy (HYPOX) in the rat causes atrophy of the intestinal mucosa, and reduction of gastric secretion and intestinal absorption, as well as increased susceptibility to bacterial and viral infections. However, to our knowledge, no findings have been published concerning the immune response following HYPOX during worm infection, particularly that which is caused by the nematode Trichinella spiralis. The aim of this work was to analyze the effects of total or partial HYPOX on colonization of T. spiralis in the intestinal lumen, together with duodenal and splenic cytokine expression. Our results indicate that 5 days post infection, only neurointermediate pituitary lobectomy (NIL) reduces the number of intestinally recovered T. spiralis larvae. Using semiquantitative inmunofluorescent laser confocal microscopy, we observed that the mean intensity of all tested Th1 cytokines was markedly diminished, even in the duodenum of infected controls. In contrast, a high level of expression of these cytokines was noted in the NIL infected hamsters. Likewise, a significant decrease in the fluorescence intensity of Th2 cytokines (with the exception of IL-4) was apparent in the duodenum of control and sham infected hamsters, compared to animals with NIL surgeries, which showed an increase in the expression of IL-5 and IL-13. Histology of duodenal mucosa from NIL hamsters showed an exacerbated inflammatory infiltrate located along the lamina propria, which was related to the presence of the parasite. We conclude that hormones from each pituitary lobe affect the gastrointestinal immune responses to T. spiralis through various mechanisms
Measurement of the cross-section and charge asymmetry of bosons produced in proton-proton collisions at TeV with the ATLAS detector
This paper presents measurements of the and cross-sections and the associated charge asymmetry as a
function of the absolute pseudorapidity of the decay muon. The data were
collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with
the ATLAS experiment at the LHC and correspond to a total integrated luminosity
of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements
varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the
1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured
with an uncertainty between 0.002 and 0.003. The results are compared with
predictions based on next-to-next-to-leading-order calculations with various
parton distribution functions and have the sensitivity to discriminate between
them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables,
submitted to EPJC. All figures including auxiliary figures are available at
https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13
Search for chargino-neutralino production with mass splittings near the electroweak scale in three-lepton final states in âs=13âTeV pp collisions with the ATLAS detector
A search for supersymmetry through the pair production of electroweakinos with mass splittings near the electroweak scale and decaying via on-shell W and Z bosons is presented for a three-lepton final state. The analyzed proton-proton collision data taken at a center-of-mass energy of âs=13ââTeV were collected between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 139ââfbâ1. A search, emulating the recursive jigsaw reconstruction technique with easily reproducible laboratory-frame variables, is performed. The two excesses observed in the 2015â2016 data recursive jigsaw analysis in the low-mass three-lepton phase space are reproduced. Results with the full data set are in agreement with the Standard Model expectations. They are interpreted to set exclusion limits at the 95% confidence level on simplified models of chargino-neutralino pair production for masses up to 345 GeV
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