Inner southern magnetosphere observation of Mercury via SERENA ion sensors in BepiColombo mission

Mercury's southern inner magnetosphere is an unexplored region as it was not observed by earlier space missions. In October 2021, BepiColombo mission has passed through this region during its first Mercury flyby. Here, we describe the observations of SERENA ion sensors nearby and inside Mercury's magnetosphere. An intermittent high-energy signal, possibly due to an interplanetary magnetic flux rope, has been observed downstream Mercury, together with low energy solar wind. Low energy ions, possibly due to satellite outgassing, were detected outside the magnetosphere. The dayside magnetopause and bow-shock crossing were much closer to the planet than expected, signature of a highly eroded magnetosphere. Different ion populations have been observed inside the magnetosphere, like low latitude boundary layer at magnetopause inbound and partial ring current at dawn close to the planet. These observations are important for understanding the weak magnetosphere behavior so close to the Sun, revealing details never reached before.

Sulfonimides versus ketosulfonamides as epoxidized imidazolium counterions: towards a new generation of ionic liquid monomers

Ionic liquid monomers with various sulfonimides or ketosulfonamides as unprecedented counteranions of imidazolium ILs were submitted to the Prilezhaev reaction and the intrinsic properties of these new epoxy monomers was unveiled.

A radiation belt of energetic protons located between Saturn and its rings

Saturn has a sufficiently strong dipole magnetic field to trap high-energy charged particles and form radiation belts, which have been observed outside its rings. Whether stable radiation belts exist near the planet and inward of the rings was previously unknown. The Cassini spacecraft’s Magnetosphere Imaging Instrument obtained measurements of a radiation belt that lies just above Saturn’s dense atmosphere and is decoupled from the rest of the magnetosphere by the planet’s A- to C-rings. The belt extends across the D-ring and comprises protons produced through cosmic ray albedo neutron decay and multiple charge-exchange reactions. These protons are lost to atmospheric neutrals and D-ring dust. Strong proton depletions that map onto features on the D-ring indicate a highly structured and diverse dust environment near Saturn.

The properties of new epoxy networks swollen with ionic liquids

In this work, ionic liquids based on trihexyl(tetradecyl)phosphonium associated with bis(2,4,4-trimethylpentyl)phosphinate [TMP] and dicyanamide [DCA] counter anions were used as reactive additives within epoxy/amine networks.

Ionic compatibilization of polypropylene/polyamide 6 blends using an ionic liquids/nanotalc filler combination: morphology, thermal and mechanical properties

In this study, room temperature ionic liquids (RTILs) based on phosphonium cations have been used as effective compatibilizers of polyolefin/polyamide 6/synthetic talc blends using a melt extrusion process.

The SupraThermal Ion Monitor for space weather predictions

Measurement of suprathermal energy ions in the heliosphere has always been challenging because (1) these ions are situated in the energy regime only a few times higher than the solar wind plasma, where intensities are orders of magnitude higher and (2) ion energies are below or close to the threshold of state-of-art solid-state detectors. Suprathermal ions accelerated at coronal mass ejection-driven shocks propagate out ahead of the shocks. These shocks can cause geomagnetic storms in the Earth's magnetosphere that can affect spacecraft and ground-based power and communication systems. An instrument with sufficient sensitivity to measure these ions can be used to predict the arrival of the shocks and provide an advance warning for potentially geo-effective space weather. In this paper, we present a novel energy analyzer concept, the Suprathermal Ion Monitor (STIM) that is designed to measure suprathermal ions with high sensitivity. We show results from a laboratory prototype and demonstrate the feasibility of the concept. A list of key performances is given, as well as a discussion of various possible detectors at the back end. STIM is an ideal candidate for a future space weather monitor in orbit upstream of the near-earth environment, for example, around L1. A scaled-down version is suitable for a CubeSat mission. Such a platform allows proofing the concept and demonstrating its performance in the space environment.

Genetic structure of Barbus spp. populations in the Marches Region of central Italy and its relevance to conservation actions

A genetic survey of Barbus spp. populations in the Marches Region (Adriatic River basins), central Italy, was carried out using mitochondrial and nuclear markers (partial D-loop, cyt b sequences and microsatellite loci) in order to ascertain their systematic position and to address their genetic structure which is key to conservation action planning. Analyses were conducted on sequences obtained from 91 individuals collected from eight sampling sites in five different rivers, from two specimens provided by the Ichthyological Centre of Rome and mitochondrial sequences of Barbus spp. retrieved from GenBank. Presumptive classification based on external morphological characters was not confirmed by genetic analysis, by means of which all specimens collected in the Marches Region were ascribed to Barbus plebejus. Genetic diversity values (h and π) of sampling groups were all different from 0 except the one sample collected from the upper reaches of the River Tenna, above a hydroelectric dam. Population connectivity and colonization patterns of the studied area were inferred from an analysis of molecular variance distribution and evolutionary relationships among haplotypes. The results point to different levels of isolation among sampling groups due to ecological and anthropogenic factors and the effect of an artificial barrier on genetic variability and conservation status of the population. Finally, this study confirms the uncertainty associated with systematic classification of Barbus spp. based on morphological characters due to the phenotypic plasticity of the species.

Global observations of the interstellar interaction from the Interstellar Boundary Explorer (IBEX)

The Sun moves through the local interstellar medium, continuously emitting ionized, supersonic solar wind plasma and carving out a cavity in interstellar space called the heliosphere. The recently launched Interstellar Boundary Explorer (IBEX) spacecraft has completed its first all-sky maps of the interstellar interaction at the edge of the heliosphere by imaging energetic neutral atoms (ENAs) emanating from this region. We found a bright ribbon of ENA emission, unpredicted by prior models or theories, that may be ordered by the local interstellar magnetic field interacting with the heliosphere. This ribbon is superposed on globally distributed flux variations ordered by both the solar wind structure and the direction of motion through the interstellar medium. Our results indicate that the external galactic environment strongly imprints the heliosphere.

Global observations of the interstellar interaction from the Interstellar Boundary Explorer (IBEX)

The Sun moves through the local interstellar medium, continuously emitting ionized, supersonic solar wind plasma and carving out a cavity in interstellar space called the heliosphere. The recently launched Interstellar Boundary Explorer (IBEX) spacecraft has completed its first all-sky maps of the interstellar interaction at the edge of the heliosphere by imaging energetic neutral atoms (ENAs) emanating from this region. We found a bright ribbon of ENA emission, unpredicted by prior models or theories, that may be ordered by the local interstellar magnetic field interacting with the heliosphere. This ribbon is superposed on globally distributed flux variations ordered by both the solar wind structure and the direction of motion through the interstellar medium. Our results indicate that the external galactic environment strongly imprints the heliosphere.

The entrance system laboratory prototype for an advanced mass and ionic charge composition experiment

Electrostatic analyzers (ESA) have been used extensively for the characterization of plasmas in a variety of space environments. They vary in shape, geometry, and size and are adapted to the specific particle population to be measured and the configuration of the spacecraft. Their main function is to select the energy per charge of the particles within a passband. An energy-per-charge range larger than that of the passband can be sampled by varying the voltage difference between the ESA electrodes. The voltage sweep takes time and reduces the duty cycle for a particular energy-per-charge passband. Our design approach for an advanced mass and ionic charge composition experiment (AMICCE) has a novel electrostatic analyzer that essentially serves as a spectrograph and selects ions simultaneously over a broad range of energy-per-charge (E/q). Only three voltage settings are required to cover the entire range from approximately 10 to 270 keV/q, thus dramatically increasing the product of the geometric factor times the duty cycle when compared with other instruments. In this paper, we describe the AMICCE concept with particular emphasis on the prototype of the entrance system (ESA and collimator), which we designed, developed, and tested. We also present comparisons of the laboratory results with electrostatic simulations.

Methylamine-dependent release of nitric oxide and dopamine in the CNS modulates food intake in fasting rats

BACKGROUND AND PURPOSE

Methylamine is an endogenous aliphatic amine exhibiting anorexigenic properties in mice. The aim of this work was to show whether methylamine also modifies feeding behaviour in rats and, if so, to identify the mediator(s) responsible for such effects.

EXPERIMENTAL APPROACH

Microdialysis experiments with the probe inserted in the periventricular hypothalamic nucleus were carried out in 12 h starved, freely moving rats. Collected perfusate samples following methylamine injection (i.c.v.) were analysed for nitric oxide by chemiluminescence and for dopamine and 5-hydroxytryptamine content by HPLC. Kv1.6 potassium channel expression was reduced by antisense strategy and this decrease quantified by semi-quantitative RT-PCR analysis.

KEY RESULTS

Methylamine showed biphasic dose-related effects on rat feeding. At doses of 15-30 microg per rat, it was hyperphagic whereas higher doses (60-80 microg) were hypophagic. Methylamine stimulated central nitric oxide (+115% vs. basal) following hyperphagic and dopamine release (60% over basal values) at hypophagic doses, respectively. Treatment with L-N(G)-nitro-L-arginine-methyl ester (i.c.v. 2 microg 10 microl(-1)) or with alpha-methyl-p-tyrosine (i.p. 100 mg kg(-1)) before methylamine injection, reduced nitric oxide output and hyperphagia, or dopamine release and hypophagia respectively. Moreover, hypophagia and hyperphagia, as well as nitric oxide and dopamine release were significantly reduced by down-regulating brain Kv1.6 potassium channel expression.

CONCLUSIONS AND IMPLICATIONS

The effects of methylamine on feeding depend on the hypothalamic release of nitric oxide and dopamine as a result of interaction at the Kv1.6 channels. The study of methylamine levels in the CNS may provide new perspectives on the physiopathology of alimentary behaviour.

Anti-planetward auroral electron beams at Saturn

Strong discrete aurorae on Earth are excited by electrons, which are accelerated along magnetic field lines towards the planet. Surprisingly, electrons accelerated in the opposite direction have been recently observed. The mechanisms and significance of this anti-earthward acceleration are highly uncertain because only earthward acceleration was traditionally considered, and observations remain limited. It is also unclear whether upward acceleration of the electrons is a necessary part of the auroral process or simply a special feature of Earth's complex space environment. Here we report anti-planetward acceleration of electron beams in Saturn's magnetosphere along field lines that statistically map into regions of aurora. The energy spectrum of these beams is qualitatively similar to the ones observed at Earth, and the energy fluxes in the observed beams are comparable with the energies required to excite Saturn's aurora. These beams, along with the observations at Earth and the barely understood electron beams in Jupiter's magnetosphere, demonstrate that anti-planetward acceleration is a universal feature of aurorae. The energy contained in the beams shows that upward acceleration is an essential part of the overall auroral process.

Dynamics of Saturn's Magnetosphere from MIMI During Cassini's Orbital Insertion

The Magnetospheric Imaging Instrument (MIMI) onboard the Cassini spacecraft observed the saturnian magnetosphere from January 2004 until Saturn orbit insertion (SOI) on 1 July 2004. The MIMI sensors observed frequent energetic particle activity in interplanetary space for several months before SOI. When the imaging sensor was switched to its energetic neutral atom (ENA) operating mode on 20 February 2004, at approximately 10(3) times Saturn's radius RS (0.43 astronomical units), a weak but persistent signal was observed from the magnetosphere. About 10 days before SOI, the magnetosphere exhibited a day-night asymmetry that varied with an approximately 11-hour periodicity. Once Cassini entered the magnetosphere, in situ measurements showed high concentrations of H+, H2+, O+, OH+, and H2O+ and low concentrations of N+. The radial dependence of ion intensity profiles implies neutral gas densities sufficient to produce high loss rates of trapped ions from the middle and inner magnetosphere. ENA imaging has revealed a radiation belt that resides inward of the D ring and is probably the result of double charge exchange between the main radiation belt and the upper layers of Saturn's exosphere.

Solar Wind-Induced Atmospheric Erosion at Mars: First Results from ASPERA-3 on Mars Express

The Analyzer of Space Plasma and Energetic Atoms (ASPERA) on board the Mars Express spacecraft found that solar wind plasma and accelerated ionospheric ions may be observed all the way down to the Mars Express pericenter of 270 kilometers above the dayside planetary surface. This is very deep in the ionosphere, implying direct exposure of the martian topside atmosphere to solar wind plasma forcing. The low-altitude penetration of solar wind plasma and the energization of ionospheric plasma may be due to solar wind irregularities or perturbations, to magnetic anomalies at Mars, or both.

The southern high-speed stream: results from the SWICS instrument on Ulysses

The high-speed solar wind streaming from the southern coronal hole was remarkably uniform and steady and was confined by a sharp boundary that extended to the corona and chromosphere. Charge state measurements indicate that the electron temperature in this coronal hole reached a maximum of about 1.5 million kelvin within 3 solar radii of the sun. This result, combined with the observed lack of depletion of heavy elements, suggests that an additional source of momentum is required to accelerate the polar wind.

Plasma Composition in Jupiter's Magnetosphere: Initial Results from the Solar Wind Ion Composition Spectrometer

The ion composition in the Jovian environment was investigated with the Solar Wind Ion Composition Spectrometer on board Ulysses. A hot tenuous plasma was observed throughout the outer and middle magnetosphere. In some regions two thermally different components were identified. Oxygen and sulfur ions with several different charge states, from the volcanic satellite lo, make the largest contribution to the mass density of the hot plasma, even at high latitude. Solar wind particles were observed in all regions investigated. Ions from Jupiter's ionosphere were abundant in the middle magnetosphere, particularly in the highlatitude region on the dusk side, which was traversed for the first time.

Effects of two doses of the fixed-combination chlorthalidone and slow-release metoprolol on blood pressure at rest and during exercise: a multicenter study

To assess the efficacy and tolerability of two doses of chlorthalidone (CHL) and slow-release (SR) metoprolol (MET) given in fixed combination (standard dose: CHL 25 mg and MET 200 mg; lower dose: CHL 12.5 mg and MET 100 mg), a multicenter (5 Centers), double-blind, between-patients study was planned. Seventy-three mild to moderate hypertensive patients, 45 males and 28 females, aged 25-68 years (mean 51.4), at WHO stage I or II, were enrolled into the study. After a 2-week placebo wash-out period, eligible patients were randomly given either of the two drugs for six weeks: 33 were given the standard dose and 40 the lower one. Every 2 weeks, in the morning and 24 h after-dosing lying and standing systolic (SBP), diastolic blood pressure (DBP) and heart rate (HR) were recorded at rest. At the end of the placebo period and at the end of the study 24 h after-dosing a sub-maximal bicycle ergometer exercise test was performed. In comparison with placebo, both doses induced a significance decrease (p less than 0.01) in lying and standing SBP, DBP and HR, as well as in peak-exercise SBP, HR and pressure-rate product. Furthermore, a significant difference (p less than 0.05) of the higher dose versus the lower one was also observed at the end of the study in the above-mentioned parameters except for SBP at rest and at peak exercise and standing HR at rest.(ABSTRACT TRUNCATED AT 250 WORDS)

A low-cost microcomputer system for automated analysis of intracellular cardiac action potentials

A microcomputer system for automated analysis of action potentials recorded from cardiac Purkinje fibers is described. The system is based upon a DMD 800 microcomputer built around a Z80 microprocessor. Two different sampling intervals are used for analog-to-digital conversion of action potential recorded from driven fibers. The following parameters can be obtained on-line: action potential amplitude; overshoot; maximum diastolic potential; action potential duration measured both at -60 mV and at 90% of complete repolarization; and maximum rate of rise of the upstroke. The digitized form of five consecutive action potentials can be stored on a floppy disk. The automated system eliminates hand measurements; the on-line analysis of the action potentials during pharmacological interventions allows a rapid appreciation of drug effects.

[Evaluation of various cardiovascular parameters during the intravenous administration of ranitidine]

In this paper we evaluated whether a block of cardiac H2 histamine receptors by ranetidine could modify some non-invasive indices of cardiac function: PEP/LVET, heart rate, blood pressure. Five healthy volunteers underwent studies in baseline conditions and 5, 10, 15, 30, 45 minutes following i.v. injections of 1, 5 m/g Kg of ranitidine. None of the studied parameters showed any significant variation at the various time intervals. Ranetidine does not appear to alter the cardiovascular function at the dose we used.

[Comparative evaluation of the effects of intravenous administration of cimetidine and ranitidine on several cardiovascular parameters]

We have compared the effects of intravenous administration of cimetidine and ranetidine on some cardiovascular parameters. Five healthy volunteers received both cimetidine (3, 5 mg/Kg) and ranetidine (1, 5 mg/Kg). Heart rate, blood pressure and PEP/LVET were recorded at baseline and 5, 10, 30, 45 minutes after administration of both drugs. Intravenous administration of cimetidine and ranetidine did not induce any significant alterations in cardiovascular variables.