Saturn's near-equatorial ionospheric conductivities from in situ measurements.

Cassini's Grand Finale orbits provided for the first time in-situ measurements of Saturn's topside ionosphere. We present the Pedersen and Hall conductivities of the top near-equatorial dayside ionosphere, derived from the in-situ measurements by the Cassini Radio and Wave Plasma Science Langmuir Probe, the Ion and Neutral Mass Spectrometer and the fluxgate magnetometer. The Pedersen and Hall conductivities are constrained to at least 10-5-10-4 S/m at (or close to) the ionospheric peak, a factor 10-100 higher than estimated previously. We show that this is due to the presence of dusty plasma in the near-equatorial ionosphere. We also show the conductive ionospheric region to be extensive, with thickness of 300-800 km. Furthermore, our results suggest a temporal variation (decrease) of the plasma densities, mean ion masses and consequently the conductivities from orbit 288 to 292.

The low-frequency source of Saturn's kilometric radiation.

Understanding how auroral radio emissions are produced by magnetized bodies requires in situ measurements within their source region. Saturn's kilometric radiation (SKR) has been widely used as a remote proxy of Saturn's magnetosphere. We present wave and plasma measurements from the Cassini spacecraft during its ring-grazing high-inclination orbits, which passed three times through the high-altitude SKR emission region. Northern dawn-side, narrow-banded radio sources were encountered at frequencies of 10 to 20 kilohertz, within regions of upward currents mapping to the ultraviolet auroral oval. The kilometric waves were produced on the extraordinary mode by the cyclotron maser instability from 6- to 12-kilo-electron volt electron beams and radiated quasi-perpendicularly to the auroral magnetic field lines. The SKR low-frequency sources appear to be strongly controlled by time-variable magnetospheric electron densities.

Dust grains fall from Saturn's D-ring into its equatorial upper atmosphere.

The sizes of Saturn's ring particles range from meters (boulders) to nanometers (dust). Determination of the rings' ages depends on loss processes, including the transport of dust into Saturn's atmosphere. During the Grand Finale orbits of the Cassini spacecraft, its instruments measured tiny dust grains that compose the innermost D-ring of Saturn. The nanometer-sized dust experiences collisions with exospheric (upper atmosphere) hydrogen and molecular hydrogen, which forces it to fall from the ring into the ionosphere and lower atmosphere. We used the Magnetospheric Imaging Instrument to detect and characterize this dust transport and also found that diffusion dominates above and near the altitude of peak ionospheric density. This mechanism results in a mass deposition into the equatorial atmosphere of ~5 kilograms per second, constraining the age of the D-ring.

Chemical interactions between Saturn's atmosphere and its rings.

The Pioneer and Voyager spacecraft made close-up measurements of Saturn's ionosphere and upper atmosphere in the 1970s and 1980s that suggested a chemical interaction between the rings and atmosphere. Exploring this interaction provides information on ring composition and the influence on Saturn's atmosphere from infalling material. The Cassini Ion Neutral Mass Spectrometer sampled in situ the region between the D ring and Saturn during the spacecraft's Grand Finale phase. We used these measurements to characterize the atmospheric structure and material influx from the rings. The atmospheric He/H2 ratio is 10 to 16%. Volatile compounds from the rings (methane; carbon monoxide and/or molecular nitrogen), as well as larger organic-bearing grains, are flowing inward at a rate of 4800 to 45,000 kilograms per second.

In situ measurements of Saturn's ionosphere show that it is dynamic and interacts with the rings.

The ionized upper layer of Saturn's atmosphere, its ionosphere, provides a closure of currents mediated by the magnetic field to other electrically charged regions (for example, rings) and hosts ion-molecule chemistry. In 2017, the Cassini spacecraft passed inside the planet's rings, allowing in situ measurements of the ionosphere. The Radio and Plasma Wave Science instrument detected a cold, dense, and dynamic ionosphere at Saturn that interacts with the rings. Plasma densities reached up to 1000 cubic centimeters, and electron temperatures were below 1160 kelvin near closest approach. The density varied between orbits by up to two orders of magnitude. Saturn's A- and B-rings cast a shadow on the planet that reduced ionization in the upper atmosphere, causing a north-south asymmetry.

Titan's ionosphere: A survey of solar EUV influences.

Effects of solar EUV on positive ions and heavy negative charge carriers (molecular ions, aerosol, and/or dust) in Titan's ionosphere are studied over the course of almost 12 years, including 78 flybys below 1400 km altitude between TA (October 2004) and T120 (June 2016). The Radio and Plasma Wave Science/Langmuir Probe-measured ion charge densities (normalized by the solar zenith angle) show statistically significant variations with respect to the solar EUV flux. Dayside charge densities increase by a factor of ≈2 from solar minimum to maximum, while nightside charge densities are found to anticorrelate with the EUV flux and decrease by a factor of ≈3-4. The overall EUV dependence of the ion charge densities suggest inapplicability of the idealized Chapman theory below 1200 km in Titan's ionosphere. Nightside charge densities are also found to vary along Titan's orbit, with higher values in the sunward magnetosphere of Saturn compared to the magnetotail.

Ion Trapping by Dust Grains: Simulation Applications to the Enceladus Plume.

Using a particle-in-cell electrostatic simulation, we examine the conditions that allow low energy ions, like those produced in the Enceladus plume, to be attracted and trapped within the sheaths of negatively-charged dust grains. The conventional wisdom is that all new ions produced in the Enceladus plume are free to get picked up (i.e., accelerated by the local E-field to then undergo vB acceleration). However, we suggest herein that the presence of submicron charged dust in the plume impedes this pickup process since the local grain electric field greatly exceeds the co-rotation E-fields. The simulations demonstrate that cold ions will tend to accelerate toward the negatively charged grains and become part of the ion plasma sheath. These trapped ions will move with the grains, exiting the plume region at the dust speed. We suggest that Cassini's Langmuir probe is measuring the entire ion population (free and trapped ions), while the Cassini magnetometer detects the magnetic perturbations associated with pickup currents from the smaller population of free ions, with this distinction possibly reconciling the ongoing debate in the literature on the ion density in the plume.

Dust observations at orbital altitudes surrounding Mars.

Dust is common close to the martian surface, but no known process can lift appreciable concentrations of particles to altitudes above ~150 kilometers. We present observations of dust at altitudes ranging from 150 to above 1000 kilometers by the Langmuir Probe and Wave instrument on the Mars Atmosphere and Volatile Evolution spacecraft. Based on its distribution, we interpret this dust to be interplanetary in origin. A comparison with laboratory measurements indicates that the dust grain size ranges from 1 to 12 micrometers, assuming a typical grain velocity of ~18 kilometers per second. These direct observations of dust entering the martian atmosphere improve our understanding of the sources, sinks, and transport of interplanetary dust throughout the inner solar system and the associated impacts on Mars's atmosphere.

Cassini measurements of cold plasma in the ionosphere of Titan.

The Cassini Radio and Plasma Wave Science (RPWS) Langmuir probe (LP) sensor observed the cold plasma environment around Titan during the first two flybys. The data show that conditions in Saturn's magnetosphere affect the structure and dynamics deep in the ionosphere of Titan. The maximum measured ionospheric electron number density reached 3800 per cubic centimeter near closest approach, and a complex chemistry was indicated. The electron temperature profiles are consistent with electron heat conduction from the hotter Titan wake. The ionospheric escape flux was estimated to be 10(25) ions per second.

[Epilepsy in patients with severe motor and intellectual disabilities: a long-term follow-up].

Long-term prognosis of epilepsy was investigated on 117 institutionalized patients with severe motor and intellectual disabilities, who were above 15 years of age in 1977, for a 20-year-period from 1977 to 1997. The incidence of epilepsy was 64.1% (75 patients), which was active in 28 patients (37.3%). The patients with the most severe psychomotor disabilities (bedridden and DQ < 20) showed the highest incidence of epilepsy (85.0%). Patients who died during the follow-up period showed higher incidence of active epilepsy (p < 0.01). During the follow-up of 94 surviving patients, persistence, relapse, and onset of seizures were frequent in patients with most severe intellectual disability, whereas those with less severe intellectual disability (20 < DQ < 35) were all seizure-free. Twenty-one patients had active epilepsy; symptomatic partial epilepsy in 17 (81.0%) and generalized epilepsy in 4 (19.0%). Notably, 5 of the 6 patients with persistent frequent seizures had age-dependent epileptic encephalopathy; persistent Lennox-Gastaut syndrome (LGS) (2 patients), severe epilepsy with multiple independent spike foci evolved from West syndrome (WS) and LGS (2 patients), and partial epilepsy with the history of LGS (1 patient).

[T 0 N 2 M 0 small cell lung cancer in a patient with Lambert-Eaton myasthenic syndrome].

We report an unusual case of T 0 N 2 M 0 small cell lung cancer in a patient with Lambert-Eaton myasthenic syndrome (LEMS). A 52-year-old man began to notice muscle weakness in a left limb in January 1996, which was followed by muscle weakness in his left arm and fingers, appetite loss, and general fatigue. An electromyogram (EMG) showed the waxing phenomenon in response to high-frequency repetitive stimulation. Lambest-Eaton myasthenic syndrome was diagnosed, based on his symptoms and EMG findings. Chest computed tomography (CT) was done, and left paratracheal, tracheobronchial, subaortic, and hilar lymphadenopathy were found. No mass was seen in either lung field. Cytologic examination of the sputum and bronchial lavage fluid were done, but no malignant cells were found Small cell lung cancer was diagnosed after thoracoscopic resection of the subaortic lymph nodes. No metastases were detected by bone scintigraphy, abdominal CT, or magnetic resonance imaging of the brain. Complete response and resolution of symptoms were obtained by chemotherapy and irradiation.

Five cases of thrombocytopenia induced by primary human herpesvirus 6 infection.

Five patients suffering from exanthem subitum with thrombocytopenia were confirmed as primary human herpesvirus 6 (HHV-6) infection by serological test. All cases had thrombocytopenia during the acute phase of exanthem subitum. The clinical features of these cases were benign, and all recovered without any specific treatment. Moreover, 4 of the 5 cases showed a mild elevation of hepatic transaminase during the same period, and other viral infections including cytomegalovirus, Epstein-Barr virus, and human herpesvirus 7 were ruled out in these patients. It was speculated that direct inhibition of platelet production by the virus or cytokine induced by the virus-infected cells was the mechanism of the thrombocytopenia induced by primary HHV-6 infection.

[Interstitial pneumonia caused by manidipine HCl].

A 62-year-old woman was given a diagnosis of rheumatoid lung in 1993. She began receiving manidipine HCl (10 mg per day) on June 19, 1996 to treat hypertension. The next day fever, coughing and dyspnea developed. She was admitted to our hospital on June 28. A chest radiograph showed diffuse reticulo-nodular shadows in all lung fields and arterial blood gas analysis revealed severe hypoxemia. Administration of manidipine HCl was stopped and treatment with methylprednisolone was started. The symptoms and the radiographic evidence of infiltrates disappeared. A drug lymphocyte stimulation test for manidipine HCl was positive. We know of no previous report of pneumonia caused by manidipine HCl.

[Long-term follow-up study of children with minimal change nephrotic syndrome].

We conducted a long-term follow-up study of 37 children with biopsy-proved minimal change nephrotic syndrome during a period of over 6 years from onset to adulthood. These patients were classified into 4 groups of 13 infrequent relapsers, 17 frequent relapsers, 3 non-responders and 4 no-relapsers according to the International Study of Kidney Disease in Children (ISKDC). All patients were treated with conventional prednisolone therapy. Two cases of infrequent relapsers, 7 cases of frequent relapsers and 1 case of non responders relapsed in adult life. Two cases of infrequent relapsers and 1 case of frequent relapsers relapsed in adult life after remission for 5 or more years. We concluded that minimal change nephrotic syndromes in childhood should be followed up over a long duration in adult life, evenly in cases with good steroid responsiveness.

[Exercise-induced acute renal failure observed in a boy with idiopathic renal hypouricemia caused by postsecretary reabsorption defect of uric acid].

Acute renal failure without oliguria developed in an 11-year boy after running exercise. With improvement of his renal function, marked hypouricemia became apparent (0.8-0.9 mg/dl). Increased excretion of uric acid into the urine, increased clearance ratio of uric acid against creatinine (CUA/CCr), normal concentration of plasma xanthine and hypoxanthine, and suppression of CUA/CCr ratio by pyrazinamide loading but not by probenecid, were observed in the patient and his two siblings, suggesting that hereditary abnormalities of reabsorption of uric acid after secretion from the renal tubules resulted in the hypouricemia. The mechanism of acute renal failure in this disease remains unknown.

Two New Steroidal Glucuronides from Solanum lyratum, II1.

Two new steroidal glucuronides of a furostanol and of a spirostanol derivative along with two known glycosides, SL-a and tigogenin 3- O-beta- D-glucopyranoside, were isolated from the aerial parts of SOLANUM LYRATUM.