In this paper we present a portable magnetocardiography device. The focus of this development was delivering a rapid assessment of chest pain in an emergency department. The aim was therefore to ...produce an inexpensive device that could be rapidly deployed in a noisy unshielded ward environment. We found that induction coil magnetometers with a coil design optimized for magnetic field mapping possess sufficient sensitivity (\(104fT/\sqrt{Hz}\) noise floor at 10Hz) and response (\(813fT/\mu V\) at 10Hz) for cycle averaged magnetocardiography and are able to measure depolarisation signals in an unshielded environment. We were unable to observe repolarisation signals to a reasonable fidelity. We present the design of the induction coil sensor array and signal processing routine along with data demonstrating performance in a hospital environment.
Cultured endothelial cells from human umbilical cord labeled with 3H20:4 release radiolabel when exposed to leukotrienes C or D (LTC or LTD). The major radiolabeled 20:4 metabolite recovered in the ...culture medium was prostacyclin. Both leukotrienes produced a dose-dependent synthesis of prostacyclin, with a maximal response at 10(-7) M leukotriene. LTC promoted a twofold greater response than did LTD at all concentrations tested (10(-9) to 10(-7) M). In contrast, no release of radiolabel above basal levels was evident with a challenge of LTE or LTB at the same concentrations. Endothelial cells metabolize approximately 40-50% of exogenously supplied LTC to LTD and LTE in 60 min. Levels of alpha-glutamyltranspeptidase (gamma-GTPase), the ectoenzyme reported to convert LTC or LTD, were detected in intact endothelial cells with the chromogenic substrate L-gamma-glutamyl-p-nitroanilide at levels sufficient to account for the observed rate of LTC metabolism. High concentrations of the gamma-GTPase inhibitors, glutathione and AT-125, blocked the metabolism of LTC by endothelium. These results suggest that degradation of leukotrienes by endothelium may be one mechanism for inactivation of these lipid mediators.
A modified method for isolation and culture of a pure population of rat Leydig cells is described. For obtaining crude interstitial cell suspension, decapsulated testes were dispersed in 0.02% ...collagenase solution in Ca2+, Mg2+--free Hanks medium for 1 hour. Then, approx. 5 X 10(7) cells were centrifuged in 10-90% discontinuous, isoosmotic Percoll gradient at 3000 g for 20 min. The cells from eight fractions obtained were collected and cultured in Eagle's MEM for 4 days. Using morphological methods, 1.059-1.070 g/ml density fraction contained 97% and 1.070-1.080 g/ml fraction contained 90% viable Leydig cells. The cells secreted testosterone to the culture medium and responded to LH stimulation with over four-fold increase in hormone secretion.
AlGaAs/GaAs microcavity structures with InAs/InGaAs quantum dot (QD) active regions were grown by molecular beam epitaxy (MBE) on GaAs substrates and their optical characteristics were studied. ...Methods for the optimization of optical emission properties of the InAs/InGaAs QDs and accurate calibration of the proper layer thickness are discussed. Microcavity light‐emitting diodes (MC‐LEDs) with a QD active region demonstrate narrow electroluminescence (EL) spectra (FWHM < 15 nm) accompanied by an output beam divergence of only 17°. The MC‐LED emission wavelength can be controllably changed by varying the QD material composition in combination with tuning the optical microcavity.
We discuss how astrophysical observations with the Maunakea Spectroscopic Explorer (MSE), a high-multiplexity (about 4300 fibers), wide field-of-view (1.5 square degree), large telescope aperture ...(11.25 m) facility, can probe the particle nature of dark matter. MSE will conduct a suite of surveys that will provide critical input for determinations of the mass function, phase-space distribution, and internal density profiles of dark matter halos across all mass scales. N-body and hydrodynamical simulations of cold, warm, fuzzy and self-interacting dark matter suggest that non-trivial dynamics in the dark sector could have left an imprint on structure formation. Analysed within these frameworks, the extensive and unprecedented datasets produced by MSE will be used to search for deviations away from cold and collisionless dark matter model. MSE will provide an improved estimate of the local density of dark matter, critical for direct detection experiments, and will improve estimates of the J-factor for indirect searches through self-annihilation or decay into Standard Model particles. MSE will determine the impact of low mass substructures on the dynamics of Milky Way stellar streams in velocity space, and will allow for estimates of the density profiles of the dark matter halos of Milky Way dwarf galaxies using more than an order of magnitude more tracers. In the low redshift Universe, MSE will provide critical redshifts to pin down the luminosity functions of vast numbers of satellite systems, and MSE will be an essential component of future strong lensing measurements to constrain the halo mass function. Across nearly all mass scales, the improvements offered by MSE, in comparison to other facilities, are such that the relevant analyses are limited by systematics rather than statistics.
In R. capsulatus synthesis and activity of the molybdenum and the alternative nitrogenase is controlled at three levels by the environmental factors ammonium, molybdenum, light, and oxygen. At the ...first level, transcription of the nifA1, nifA2, and anfA genes--which encode the transcriptional activators of all other nif and anf genes, respectively--is controlled by the Ntr system in dependence on ammonium availability. Mutations in ginB (coding for the signal transduction protein PII) result in significant expression of nifA and anfA in the presence of ammonium. In contrast to GlnB, the PII-paralogue GlnK is not involved in the Ntr signal transduction mechanism. In addition to ammonium control, transcription of anfA is inhibited by traces of molybdenum via the molybdate-dependent repressor proteins MopA and MopB. At the second level of regulation, activity of NifA1, NifA2, and AnfA is inhibited by ammonium in an NtrC-independent manner. This post-translational ammonium control of NifA activity is partially released in the absence of GlnK, and completely abolished in a glnB/glnK double mutant. In contrast, AnfA activity is still inhibited by ammonium in the glnB/glnK mutant background. At the third level of regulation, both GlnB and GlnK as well as the (methyl)-ammonium transporter AmtB are involved in ammonium control of the DraT/DraG system, which mediates reversible ADP-ribosylation of both nitrogenase reductases (NifH and AnfH) in response to changes in ammonium availability or light intensity. Most remarkably, in a glnB/glnK double mutant ammonium control of the molybdenum (but not of the alternative) nitrogenase is completely relieved, leading to synthesis of active nitrogenase in the presence of high concentrations of ammonium.
Within 5 min, resting macrophages metabolize microM quantities of exogenous arachidonic acid (20:4) to cyclooxygenase and lipoxygenase products. Mono-HETEs represent a major class of metabolites ...recovered from the medium. However, the quantity of mono-Hetes progressively decreases over a 60-min incubation period, with a concomitant increase in more polar lipoxygenase products, suggesting additional metabolic fates for these hydroxy acids. This was directly confirmed by exposing resident macrophage cultures to radiolabeled 15-, 12-, and 5-HETEs (1 microM). 12-30% of the recovered HETEs were cell-associated and predominantly esterified into phospholipid. High pressure liquid chromatography analyses of medium extracts indicated that 50% of each HETE was also converted to 10 or more metabolites over a 60-min time-course, a rate slower than for 20:4. The major metabolite generated from each mono-HETE had the elution characteristics of a di-HETE. The 5-HETE product has a triene spectrum similar to that of 5(S), 12(S)-di-HETE, whereas the 15- and 12-HETE products exhibited single ultraviolet absorption maxima, indicating a metabolic pathway for 5-HETE distinct from the other mono-HETEs. None of the stable cyclooxygenase products of 20:4 (6-keto PGF1 alpha, PGF2 alpha, PGE2, TXB2) nor polar metabolites of mono-HETEs are either incorporated or metabolized. The results indicate that macrophages have the capacity to specifically metabolize 20:4 and mono-HETEs to polar oxygenated products in the absence of a discernible trigger.
The genus
Ammonia is one of the most common benthic foraminifer of considerable biogeographic importance. The taxonomic status of most of the described species of
Ammonia, however, is yet unsettled. ...In the present study, we used the partial large subunit ribosomal DNA (LSU rDNA) sequences as an alternative approach to distinguish different specimens of
Ammonia living in the Lagoon of Venice. We have obtained DNA sequences from 20 living specimens whose tests were examined previously by scanning electron microscopy (SEM). Sequence analysis revealed the presence of two groups, which differ by more than 10.5%. Within each group, the sequence divergence ranges from 0.2 % to 6.9 %. The two groups that can be separated genetically, are called
Ammonia sp. 1 and
Ammonia sp. 2. Their morphological distinction, however, is problematic. The tests of
Ammonia sp. 1 are generally characterized by a more lobate periphery, more elevated dorsal sutures and larger perforations compared to those of
Ammonia sp. 2, but none of these characters can be used with certainty for the morphological distinction of both groups.
Le genre
Ammonia comprend un grand nombre d'espèces de foraminifères benthiques actuels, dont l'importance biogéographique est considérable. Cependant, le statut taxonomique de ces espèces n'est pas bien établi. Dans cette étude, nous avons utilisé les séquences de la grande sous-unité de l'ADN ribosomique afin de distinguer les différentes espèces d'
Ammonia vivant dans la Lagune de Venise. Nous avons obtenu les séquences de l'ADN de 20 spécimens, dont les tests ont été photographiés préalablement an microscope électronique à balayage. L'analyse des séquences a permis la distinction de deux groupes d'individus qui diffèrent par plus de 10,5 %. A l'intérieur de chaque groupe, les séquences divergent entre 0,2 % et 6,9 %. Sur la base de la morphologie, la distinction des deux groupes, nommés
Ammonia sp. 1 et
Ammonia sp. 2, n'est pas évidente. Les tests d'
Ammonia sp. 1 sont caractérisés par une périphérie plus lobée, des sutures plus élevées et des pores plus grands que ceux d'
Ammonia sp. 2. Cependant, en raison de la présence de formes intermédiaires, aucun de ces caractères ne peut être utilisé avec certitude pour une distinction morphologique des deux groupes.
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