Martian atmospheric hydrogen and deuterium: Seasonal changes and paradigm for escape to space.

Mars' water history is fundamental to understanding Earth-like planet evolution. Water escapes to space as atoms, and hydrogen atoms escape faster than deuterium giving an increase in the residual D/H ratio. The present ratio reflects the total water Mars has lost.

Early Treatment with Vigabatrin Does Not Decrease Focal Seizures or Improve Cognition in Tuberous Sclerosis Complex: The PREVeNT Trial.

Objective: This study was undertaken to test the hypothesis that early vigabatrin treatment in tuberous sclerosis complex (TSC) infants improves neurocognitive outcome at 24 months of age.

Methods: A phase IIb multicenter randomized double-blind placebo-controlled trial was conducted of vigabatrin at first epileptiform electroencephalogram (EEG) versus vigabatrin at seizure onset in infants with TSC. Primary outcome was Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III) cognitive assessment score at 24 months.

Pediatric screen exposure and school related headache disability.

Background And Objectives: Prolonged screen exposure is often cited as a trigger for pediatric headache. We present initial findings evaluating the association between adolescent screen use type, duration, and school disability.

Methods: New patients aged 12-17 years presenting to a headache clinic were screened and surveyed regarding headache characteristics, behavioral habits, school attendance, and screen utilization.

Natural History of Abortive Medication Withdrawal in the Management of Pediatric Medication Overuse Headache.

Objective: The objective of this study is to document pain scores during withdrawal of abortive medication in patients diagnosed with medication overuse headache.

Design: Cross-sectional study.

Setting: Children's National Hospital's Headache Program.

New Daily Persistent Headache in a Pediatric Population.

Introduction: New daily persistent headache (NDPH) is a primary headache disorder characterized by an intractable, daily, and unremitting headache lasting for at least 3 months. Currently, there are limited studies in the pediatric population describing the characteristics of NDPH.

Objective: The objective of the current study is to describe the characteristics of NDPH in pediatric patients presenting to a headache program at a tertiary referral center.

First Global-Scale Synoptic Imaging of Solar Eclipse Effects in the Thermosphere.

A total solar eclipse occurred in the Southern Hemisphere on 2 July 2019 from approximately 17 to 22 UT. Its effect in the thermosphere over South America was imaged from geostationary orbit by NASA's Global-scale Observation of Limb and Disk (GOLD) instrument. GOLD observed a large brightness reduction (>80% around totality) in OI 135.

Variations of Lower Thermospheric FUV Emissions Based on GOLD Observations and GLOW Modeling.

Here we compare the global-scale morphology of Earth's the Far-Ultraviolet (FUV) emissions observed by NASA's Global-scale Observations of Limb and Disk (GOLD) mission to those modeled using the Global Airglow (GLOW) code with atmospheric parameters provided by Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIEGCM). The O S oxygen (135.6 nm) and N Lyman-Birge-Hopfield (LBH) emissions are observed over the Western hemisphere every 30 min by the GOLD instrument.

"Laser and the Tuber": thermal dynamic and volumetric factors influencing seizure outcomes in pediatric subjects with tuberous sclerosis undergoing stereoencephalography-directed laser ablation of tubers.

Purpose: Tuberous sclerosis (TSC) is a well-known cause of medically refractory epilepsy (MRE). Stereoencephalography-directed magnetic resonance-guided laser interstitial thermal therapy (SEEG-directed MRgLITT) is an emerging minimally invasive technique that appears aptly suited for the surgical management of TSC. Our aims are to present our experiences with patients who had undergone SEEG-directed MRgLITT to identify and treat cortical tubers responsible for clinical seizures and to perform an in-depth analysis of volumetric and thermal dynamic factors that may be related to seizure outcomes.

Rett syndrome (MECP2) and succinic semialdehyde dehydrogenase (ALDH5A1) deficiency in a developmentally delayed female.

Background: We present a patient with Rett syndrome (RTT; MECP2) and autosomal-recessive succinic semialdehyde dehydrogenase deficiency (SSADHD; ALDH5A1 (aldehyde dehydrogenase 5a1 = SSADH), in whom the current phenotype exhibits features of SSADHD (hypotonia, global developmental delay) and RTT (hand stereotypies, gait anomalies).

Methods: γ-Hydroxybutyric acid (GHB) was quantified by UPLC-tandem mass spectrometry, while mutation analysis followed standard methodology of whole-exome sequencing.

Results: The biochemical hallmark of SSADHD, GHB was increased in the proband's dried bloodspot (DBS; 673 µM; previous SSADHD DBSs (n = 7), range 124-4851 µM); control range (n = 2,831), 0-78 µM.

A Cold-Pole Enhancement in Mercury's Sodium Exosphere.

The Ultraviolet and Visible Spectrometer (UVVS) component of the Mercury Atmospheric and Surface Composition Spectrometer (MASCS) on the MESSENGER spacecraft characterized the local-time distribution of the sodium exosphere over the course of its orbital mission. The observations show that the sodium exosphere is enhanced above Mercury's cold-pole longitudes. Based on previously published sodium exosphere models we infer that these regions act as nightside surface reservoirs, temporary sinks to the exosphere that collect sodium atoms transported anti-sunward.

Optical coherence tomography to monitor vigabatrin toxicity in children.

Purpose: The antiepileptic drug vigabatrin is known to cause permanent loss of vision. Both visual field testing and electroretinogram are used to detect retinal damage. Adult data on optical coherence tomography (OCT) shows that retinal nerve fiber layer (RNFL) thinning may be an early indicator of vigabatrin-induced retinal toxicity.

Acoustic Injectors for Drop-On-Demand Serial Femtosecond Crystallography.

X-ray free-electron lasers (XFELs) provide very intense X-ray pulses suitable for macromolecular crystallography. Each X-ray pulse typically lasts for tens of femtoseconds and the interval between pulses is many orders of magnitude longer. Here we describe two novel acoustic injection systems that use focused sound waves to eject picoliter to nanoliter crystal-containing droplets out of microplates and into the X-ray pulse from which diffraction data are collected.

The auroral footprint of Enceladus on Saturn.

Although there are substantial differences between the magnetospheres of Jupiter and Saturn, it has been suggested that cryovolcanic activity at Enceladus could lead to electrodynamic coupling between Enceladus and Saturn like that which links Jupiter with Io, Europa and Ganymede. Powerful field-aligned electron beams associated with the Io-Jupiter coupling, for example, create an auroral footprint in Jupiter's ionosphere. Auroral ultraviolet emission associated with Enceladus-Saturn coupling is anticipated to be just a few tenths of a kilorayleigh (ref.

Mercury's complex exosphere: results from MESSENGER's third flyby.

During MESSENGER's third flyby of Mercury, the Mercury Atmospheric and Surface Composition Spectrometer detected emission from ionized calcium concentrated 1 to 2 Mercury radii tailward of the planet. This measurement provides evidence for tailward magnetospheric convection of photoions produced inside the magnetosphere. Observations of neutral sodium, calcium, and magnesium above the planet's north and south poles reveal altitude distributions that are distinct for each species.

Headache in young children in the emergency department: use of computed tomography.

Objective: The goal was to determine whether computed tomographic (CT) scans led to better acute care of young children with headache presenting the emergency department (ED).

Methods: We examined the records of 364 children 2 to 5 years of age who presented with headache to a large urban ED between July 1, 2003, and June 30, 2006. By reviewing initial history and examination findings, we first identified patients with secondary headaches (ie, with readily identifiable explanations such as ventriculoperitoneal shunts, known brain tumors, or acute illnesses, such as viral syndromes, fever, probable meningitis, or trauma).

MESSENGER observations of Mercury's exosphere: detection of magnesium and distribution of constituents.

Mercury is surrounded by a tenuous exosphere that is supplied primarily by the planet's surface materials and is known to contain sodium, potassium, and calcium. Observations by the Mercury Atmospheric and Surface Composition Spectrometer during MESSENGER's second Mercury flyby revealed the presence of neutral magnesium in the tail (anti-sunward) region of the exosphere, as well as differing spatial distributions of magnesium, calcium, and sodium atoms in both the tail and the nightside, near-planet exosphere. Analysis of these observations, supplemented by observations during the first Mercury flyby, as well as those by other MESSENGER instruments, suggests that the distinct spatial distributions arise from a combination of differences in source, transfer, and loss processes.

Obesity in the pediatric headache population: a multicenter study.

Objective: To examine the prevalence of obesity, the relationship between weight compared with headache frequency and disability, and effect of weight change on headache outcomes within a pediatric headache population.

Background: Headache and obesity are both common conditions in children and adults. Research in adults has suggested a relationship between the 2 conditions.

Cerebral MRI abnormalities associated with vigabatrin therapy.

Purpose: Investigate whether patients on vigabatrin demonstrated new-onset and reversible T(2)-weighted magnetic resonance imaging (MRI) abnormalities.

Methods: MRI of patients treated during vigabatrin therapy was reviewed, following detection of new basal ganglia, thalamus, and corpus callosum hyperintensities in an infant treated for infantile spasms. Patients were assessed for age at time of MRI, diagnosis, duration, and dose, MRI findings pre-, on, and postvigabatrin, concomitant medications, and clinical correlation.

Mercury's exosphere: observations during MESSENGER's First Mercury flyby.

During MESSENGER's first Mercury flyby, the Mercury Atmospheric and Surface Composition Spectrometer measured Mercury's exospheric emissions, including those from the antisunward sodium tail, calcium and sodium close to the planet, and hydrogen at high altitudes on the dayside. Spatial variations indicate that multiple source and loss processes generate and maintain the exosphere. Energetic processes connected to the solar wind and magnetospheric interaction with the planet likely played an important role in determining the distributions of exospheric species during the flyby.

Geology of the Caloris basin, Mercury: a view from MESSENGER.

The Caloris basin, the youngest known large impact basin on Mercury, is revealed in MESSENGER images to be modified by volcanism and deformation in a manner distinct from that of lunar impact basins. The morphology and spatial distribution of basin materials themselves closely match lunar counterparts. Evidence for a volcanic origin of the basin's interior plains includes embayed craters on the basin floor and diffuse deposits surrounding rimless depressions interpreted to be of pyroclastic origin.

Volcanism on Mercury: evidence from the first MESSENGER flyby.

The origin of plains on Mercury, whether by volcanic flooding or impact ejecta ponding, has been controversial since the Mariner 10 flybys (1974-75). High-resolution images (down to 150 meters per pixel) obtained during the first MESSENGER flyby show evidence for volcanic vents around the Caloris basin inner margin and demonstrate that plains were emplaced sequentially inside and adjacent to numerous large impact craters, to thicknesses in excess of several kilometers. Radial graben and a floor-fractured crater may indicate intrusive activity.

Reflectance and color variations on Mercury: regolith processes and compositional heterogeneity.

Multispectral images of Mercury obtained by the MESSENGER spacecraft reveal that its surface has an overall relatively low reflectance with three large-scale units identified on the basis of reflectance and slope (0.4 to 1.0 micrometer).

Spectroscopic observations of Mercury's surface reflectance during MESSENGER's first Mercury flyby.

During MESSENGER's first flyby of Mercury, the Mercury Atmospheric and Surface Composition Spectrometer made simultaneous mid-ultraviolet to near-infrared (wavelengths of 200 to 1300 nanometers) reflectance observations of the surface. An ultraviolet absorption (<280 nanometers) suggests that the ferrous oxide (Fe2+) content of silicates in average surface material is low (less than 2 to 3 weight percent). This result is supported by the lack of a detectable 1-micrometer Fe2+ absorption band in high-spatial-resolution spectra of mature surface materials as well as immature crater ejecta, which suggests that the ferrous iron content may be low both on the surface and at depth.