The increased red blood cell Li+/Na+ exchange found in a subgroup of patients with essential hypertension (EH) may reflect an increased activity of the Na+/H+ exchange. The maximal velocity of the ...red cells' Na+/H+ (Na+ influx promoted by an outward H+ gradient) and Li+/Na+ (Li+ efflux promoted by external Na+) exchange were therefore measured in 41 EH and in 21 normotensive controls (NT). Both transporters were significantly higher in EH than in NT (74 +/- 39 mmol/L cell x h v 43 +/- 27 for the former, P less than .03, and 0.35 +/- 0.16 v 0.26 +/- 0.10 for the latter, P less than .05). Even though more than 100 times faster, Na+/H+ exchange was weakly but significantly correlated to Li+/Na+ exchange (r = 0.29, P less than .05). Proximal tubule Na+ reabsorption (fractional renal Li+ reabsorption) was significantly greater in EH than in NT (0.78 +/- 0.07, n = 32, v 0.73 +/- 0.06, n = 10, P less than .05) but it was not correlated to either the red cells' Na+/H+ or Li+/Na+ exchanges. Therefore, hyperactivity of Na+/H+ exchange in EH may play a role in blood pressure elevation through mechanisms other than stimulation of renal Na+ reabsorption.
In the treatment of hypertensive patients with peripheral vascular disease, alpha 1-adrenoceptor blockers may be considered first-choice drugs since they reduce the total peripheral resistance and do ...not decrease the plasma volume. As a preliminary step, we investigated the plethysmographic effects of doxazosin (1-8 mg for 6 weeks) on calf flow in 32 uncomplicated hypertensive patients. Despite the fall in sitting and standing blood pressure (from 163 +/- 18/101 +/- 6 to 147 +/- 19/94 +/- 8 mmHg and from 162 +/- 18/107 +/- 9 to 145 +/- 18/95 +/- 8 mmHg, respectively; both P less than 0.001) the calf flow was not decreased at rest and after ischaemia. Resting resistance was not significantly reduced (from 49.5 +/- 35 to 38.9 +/- 33 mmHg/100 ml per min) but its fall was significantly correlated with the fall in mean blood pressure (rs = 0.35, P less than 0.05). These findings confirm that doxazosin may be useful in the treatment of hypertension complicated by peripheral artery disease.
The Mini-EUSO instrument is a UV telescope to be placed inside the International Space Station (ISS), looking down on the Earth from a nadir-facing window in the Russian Zvezda module. Mini-EUSO will ...map the earth in the UV range (300–400nm) with a spatial resolution of 6.11km and a temporal resolution of 2.5μs, offering the opportunity to study a variety of atmospheric events such as transient luminous events (TLEs) and meteors, as well as searching for strange quark matter and bioluminescence. Furthermore, Mini-EUSO will be used to detect space debris to verify the possibility of using a EUSO-class telescope in combination with a high energy laser for space debris remediation. The high-resolution mapping of the UV emissions from Earth orbit allows Mini-EUSO to serve as a pathfinder for the study of Extreme Energy Cosmic Rays (EECRs) from space by the JEM-EUSO collaboration.
Natural history and outcome of percutaneous transluminal renal angioplasty (PTRA) in renovascular hypertension (RVH) were assessed retrospectively in 52 patients in whom 62 PTRAs were successfully ...performed. Complications were observed in 16 patients: prolonged and extensive arterial spasms in eight, severe intimal dissection of the main renal artery in five, arterial thrombosis at the site of PTRA in two and acute deterioration of renal function in one. All the complications cleared up with medical treatment except for one major dissection occluding the distal branches, which required surgery. According to the Co-operative Study, after 1-5 years of follow-up, 21 patients (40.4%) were cured, 27 (51.9%) improved and four (7.7%) did not improve. The long-term results on blood pressure in both uncomplicated and complicated cases were better in fibrodysplasia (61.5% cured, 34.6% improved and 3.8% not improved) than in atherosclerosis (17.4% cured, 69.6% improved and 13% not improved). In the last 21 PTRAs performed, in which verapamil (200-1500 micrograms) was given as a bolus injection into the stenotic artery before dilatation, the complication rate was significantly lower. It is concluded that PTRA is an effective treatment for RVH; complications occurred in 25.8% of PTRAs and resulted in poor control of blood pressure in atherosclerosis but not in fibrodysplasia; premedication with verapamil into the stenotic renal artery reduced the complication rate.
Abstract
Mini-EUSO is a telescope observing the Earth in the ultraviolet band from the International Space Station. It is a part of the JEM-EUSO program, paving the way to future larger missions, ...such as K-EUSO and POEMMA, devoted primarily to the observation of ultrahigh-energy cosmic rays from space. Mini-EUSO is capable of observing extensive air showers generated by ultrahigh-energy cosmic rays with an energy above 10
21
eV and to detect artificial showers generated with lasers from the ground. Other main scientific objectives of the mission are the search for nuclearites and strange quark matter, the study of atmospheric phenomena such as transient luminous events, meteors, and meteoroids, the observation of sea bioluminescence and of artificial satellites and man-made space debris. Mini-EUSO will map the nighttime Earth in the UV range (290–430 nm), with a spatial resolution of about 6.3 km and a temporal resolution of 2.5
μ
s, through a nadir-facing UV-transparent window in the Russian Zvezda module. The instrument, launched on 2019 August 22, from the Baikonur Cosmodrome, is based on an optical system employing two Fresnel lenses and a focal surface composed of 36 multianode photomultiplier tubes, 64 channels each, for a total of 2304 channels with single-photon counting sensitivity and an overall field of view of 44°. Mini-EUSO also contains two ancillary cameras to complement measurements in the near-infrared and visible ranges. In this paper, we describe the detector and present the various phenomena observed in the first months of operations.
An authentication study of the Italian PDO (Protected Designation of Origin) olive oil Chianti Classico, based on artificial nose, near-infrared and UV–visible spectroscopy, with a set of samples ...representative of the whole Chianti Classico production area and a considerable number of samples from other Italian PDO regions was performed.
The signals provided by the three analytical techniques were used both individually and jointly, after fusion of the respective variables, in order to build a model for the Chianti Classico PDO olive oil.
Different signal pre-treatments were performed in order to investigate their importance and their effects in enhancing and extracting information from experimental data, correcting backgrounds or removing baseline variations.
Stepwise-Linear Discriminant Analysis (STEP-LDA) was used as a feature selection technique and, afterward, Linear Discriminant Analysis (LDA) and the class-modelling technique Quadratic Discriminant Analysis-UNEQual dispersed classes (QDA-UNEQ) were applied to sub-sets of selected variables, in order to obtain efficient models capable of characterising the extra virgin olive oils produced in the Chianti Classico PDO area.
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•Artificial nose, near-infrared and UV–visible spectroscopy to analyse olive oils.•Different pre-treatments on the signals provided by the three analytical techniques.•Class modelling techniques to build a model for the Chianti Classico PDO olive oil.•Comparison and synergy among information from the different analytical techniques.
Precision measurements of the positron component in the cosmic radiation provide important information about the propagation of cosmic rays and the nature of particle sources in our Galaxy. The ...satellite-borne experiment PAMELA has been used to make a new measurement of the cosmic-ray positron flux and fraction that extends previously published measurements up to 300 GeV in kinetic energy. The combined measurements of the cosmic-ray positron energy spectrum and fraction provide a unique tool to constrain interpretation models. During the recent solar minimum activity period from July 2006 to December 2009, approximately 24,500 positrons were observed. The results cannot be easily reconciled with purely secondary production, and additional sources of either astrophysical or exotic origin may be required.
On the 15th of June 2006, the PAMELA (Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics) satellite-borne experiment was launched onboard the Russian Resurs-DK1 satellite by a ...Soyuz rocket from the Baikonur space centre. The satellite was placed in a quasi-polar 70°inclination orbit at an altitude varying between 350 km and 600 km.
New results on the antiparticle component of the cosmic radiation were obtained. The positron energy spectrum and positron fraction were measured from 400 MeV up to 200 GeV revealing a positron excess over the predictions of commonly used propagation models. This can be interpreted either as evidence that the propagation models should be revised or in terms of dark matter annihilation or a pulsar contribution. The antiproton spectrum was measured over the energy range from 60 MeV to 350 GeV. The antiproton spectrum is consistent with secondary production and significantly constrains dark matter models.
The energy spectra of protons and helium nuclei were measured up to 1.2 TV. The spectral shapes of these two species are different and cannot be described well by a single power law. For the first time the electron spectrum was measured up to 600 GeV complementing the information obtained from the positron data. Nuclear and isotopic composition was obtained with unprecedented precision.
The variation of the low energy proton, electron and positron energy spectra was measured from July 2006 until December 2009 accurately sampling the unusual conditions of the most recent solar minimum activity period (2006–2009). Low energy particle spectra were accurately measured also for various solar events that occurred during the PAMELA mission.
The Earth’s magnetosphere was studied measuring the particle radiation in different regions of the magnetosphere. Energy spectra and composition of sub-cutoff and trapped particles were obtained. For the first time a belt of trapped antiprotons was detected in the South Atlantic Anomaly region. The flux was found to exceed that for galactic cosmic-ray antiprotons by three order of magnitude.
Despite the significant progress achieved in recent years, the physical mechanisms underlying the origin of solar energetic particles (SEPs) are still a matter of debate. The complex nature of both ...particle acceleration and transport poses challenges to developing a universal picture of SEP events that encompasses both the low-energy (from tens of keV to a few hundreds of MeV) observations made by space-based instruments and the GeV particles detected by the worldwide network of neutron monitors in ground-level enhancements (GLEs). The high-precision data collected by the Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics (PAMELA) satellite experiment offer a unique opportunity to study the SEP fluxes between ∼80 MeV and a few GeV, significantly improving the characterization of the most energetic events. In particular, PAMELA can measure for the first time with good accuracy the spectral features at moderate and high energies, providing important constraints for current SEP models. In addition, the PAMELA observations allow the relationship between low- and high-energy particles to be investigated, enabling a clearer view of the SEP origin. No qualitative distinction between the spectral shapes of GLE, sub-GLE and non-GLE events is observed, suggesting that GLEs are not a separate class, but are the subset of a continuous distribution of SEP events that are more intense at high energies. While the spectral forms found are to be consistent with diffusive shock acceleration theory, which predicts spectral rollovers at high energies that are attributed to particles escaping the shock region during acceleration, further work is required to explore the relative influences of acceleration and transport processes on SEP spectra.
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