Publications by authors named "FJ Marshall"

This paper presents a simple physics-based model for the interpretation of key metrics in laser direct drive. The only input parameters required are target scale, in-flight aspect ratio, and beam-to-target radius, and the importance of each has been quantified with a tailored set of cryogenic implosion experiments. These analyses lead to compact and accurate predictions of the fusion yield and areal density as a function of hydrodynamic stability, and they suggest new ways to take advantage of direct drive.

View Article and Find Full Text PDF
Article Synopsis
  • * This experiment produced 2.05 MJ of laser energy, resulting in 3.1 MJ of total fusion yield, which exceeds the Lawson criterion for ignition, demonstrating a key milestone in fusion research.
  • * The report details the advancements in target design, laser technology, and experimental methods that contributed to this historic achievement, validating over five decades of research in laboratory fusion.
View Article and Find Full Text PDF

Background: Mild cognitive impairment is common in Parkinson disease (PD-MCI). However, instability in this clinical diagnosis and variability in rates of progression to dementia raises questions regarding its utility for longitudinal tracking and prediction of cognitive change in PD. We examined baseline neuropsychological test and cognitive diagnosis predictors of cognitive change in PD.

View Article and Find Full Text PDF
Article Synopsis
  • * In inertially confined fusion, ignition allows the fusion process to spread into surrounding fuel, potentially leading to higher energy output.
  • * Recent experiments at the National Ignition Facility achieved capsule gains of 5.8 and approached ignition, even though "scientific breakeven" has not yet been fully realized.
View Article and Find Full Text PDF

This Letter presents the first observation on how a strong, 500 kG, externally applied B field increases the mode-two asymmetry in shock-heated inertial fusion implosions. Using a direct-drive implosion with polar illumination and imposed field, we observed that magnetization produces a significant increase in the implosion oblateness (a 2.5× larger P2 amplitude in x-ray self-emission images) compared with reference experiments with identical drive but with no field applied.

View Article and Find Full Text PDF

Experiments performed at the Laboratory for Laser Energetics with a continuous-wave (cw) x-ray source and on the OMEGA and OMEGA EP Laser Systems [Boehly et al., Opt. Commun.

View Article and Find Full Text PDF

SRX246 is a vasopressin (AVP) 1a receptor antagonist that crosses the blood-brain barrier. It reduced impulsive aggression, fear, depression and anxiety in animal models, blocked the actions of intranasal AVP on aggression/fear circuits in an experimental medicine fMRI study and demonstrated excellent safety in Phase 1 multiple-ascending dose clinical trials. The present study was a 3-arm, multicenter, randomized, placebo-controlled, double-blind, 12-week, dose escalation study of SRX246 in early symptomatic Huntington's disease (HD) patients with irritability.

View Article and Find Full Text PDF

Objective: To develop a disease-specific staging system for CLN3 disease and to test the hypothesis that salient and discrete clinical features of CLN3 disease may be used to define disease stages by analyzed data from an 18-year-long natural history study.

Methods: A proposed staging system, the CLN3 Staging System (CLN3SS), was based on salient and clinically meaningful endpoints. The relationships between stage and age, stage and Unified Batten Disease Rating Scale (UBDRS) physical severity score, and stage and UBDRS capability impairment subscale scores were determined.

View Article and Find Full Text PDF

A method was developed with laser-irradiated Au planar foils to characterize the focal spot of UV laser beams on a target at full energy from soft x-ray emission. A pinhole camera with a back-thinned charge-coupled device detector and filtration with thin Be and Al foil filters provides images of the x-ray emission at photon energies <2 keV. This method requires a careful measurement of the relationship between the applied UV fluence and the x-ray signal, which can be described by a power-law dependence.

View Article and Find Full Text PDF

Background: Travel burden often substantially limits the ability of individuals to participate in clinical trials. Wide geographic dispersion of individuals with rare diseases poses an additional key challenge in the conduct of clinical trials for rare diseases. Novel technologies and methods can improve access to research by connecting participants in their homes and local communities to a distant research site.

View Article and Find Full Text PDF

Focusing laser light onto a very small target can produce the conditions for laboratory-scale nuclear fusion of hydrogen isotopes. The lack of accurate predictive models, which are essential for the design of high-performance laser-fusion experiments, is a major obstacle to achieving thermonuclear ignition. Here we report a statistical approach that was used to design and quantitatively predict the results of implosions of solid deuterium-tritium targets carried out with the 30-kilojoule OMEGA laser system, leading to tripling of the fusion yield to its highest value so far for direct-drive laser fusion.

View Article and Find Full Text PDF

The single-line-of-sight, time-resolved x-ray imager (SLOS-TRXI) on OMEGA is one of a new generation of fast-gated x-ray cameras comprising an electron pulse-dilation imager and a nanosecond-gated, burst-mode, hybrid complementary metal-oxide semiconductor sensor. SLOS-TRXI images the core of imploded cryogenic deuterium-tritium shells in inertial confinement fusion experiments in the ∼4- to 9-keV photon energy range with a pinhole imager onto a photocathode. The diagnostic is mounted on a fixed port almost perpendicular to a 16-channel, framing-camera-based, time-resolved Kirkpatrick-Baez microscope, providing a second time-gated line of sight for hot-spot imaging on OMEGA.

View Article and Find Full Text PDF
Article Synopsis
  • Unilateral deep brain stimulation (DBS) for essential tremor (ET) significantly improved axial tremor, with 58% improvement at 90 days and 65% at 180 days compared to pre-surgery levels.
  • In a subgroup that underwent staged bilateral DBS, there was a further 63% improvement in midline tremor scores, but this also came with an increase in adverse events related to the procedure.
  • The study concludes that unilateral VIM DBS may be enough to effectively reduce tremors without the need for bilateral stimulation, which carries additional risks.
View Article and Find Full Text PDF

Mycophenolate, an immunosuppressant, is commonly used off-label for autoimmune neurological conditions. In CLN3 disease, a neurodegenerative disorder of childhood, preclinical and clinical data suggest secondary autoimmunity and inflammation throughout the central nervous system are key components of pathogenesis. We tested the short-term tolerability of mycophenolate in individuals with CLN3 disease, in preparation for possible long-term efficacy trials of this drug.

View Article and Find Full Text PDF

Cross-beam energy transfer (CBET) results from two-beam energy exchange via seeded stimulated Brillouin scattering, which detrimentally reduces ablation pressure and implosion velocity in direct-drive inertial confinement fusion. Mitigating CBET is demonstrated for the first time in inertial-confinement implosions at the National Ignition Facility by detuning the laser-source wavelengths (±2.3  Å UV) of the interacting beams.

View Article and Find Full Text PDF

A 16-image Kirkpatrick-Baez (KB)-type x-ray microscope consisting of compact KB mirrors [F. J. Marshall, Rev.

View Article and Find Full Text PDF

The need for a reliable, simple, and inexpensive blood test for Alzheimer's disease (AD) suitable for use in a primary care setting is widely recognized. This has led to a large number of publications describing blood tests for AD, which have, for the most part, not been replicable. We have chosen to examine transcripts expressed by the cellular, leukocyte compartment of blood.

View Article and Find Full Text PDF

We present narrow-band self-emission x-ray images from a titanium tracer layer placed at the fuel-shell interface in 60-laser-beam implosion experiments at the OMEGA facility. The images are acquired during deceleration with inferred convergences of ∼9-14. Novel here is that a systematically observed asymmetry of the emission is linked, using full sphere 3D implosion modeling, to performance-limiting low mode asymmetry of the drive.

View Article and Find Full Text PDF
Article Synopsis
  • This study examined the effectiveness of a new constant-current device for deep brain stimulation (DBS) in reducing tremors and improving daily activities in patients with essential tremor (ET).
  • A multicenter trial involved 127 patients, assessing the impact of unilateral and bilateral DBS on tremor scores and quality of life over one year, with significant improvements noted in motor function and mood.
  • Results indicated substantial benefits from the DBS treatment, but there were also serious surgical risks, including infections and bleeding.
View Article and Find Full Text PDF

It is shown that direct-drive implosions on the OMEGA laser have achieved core conditions that would lead to significant alpha heating at incident energies available on the National Ignition Facility (NIF) scale. The extrapolation of the experimental results from OMEGA to NIF energy assumes only that the implosion hydrodynamic efficiency is unchanged at higher energies. This approach is independent of the uncertainties in the physical mechanism that degrade implosions on OMEGA, and relies solely on a volumetric scaling of the experimentally observed core conditions.

View Article and Find Full Text PDF

A record fuel hot-spot pressure P_{hs}=56±7  Gbar was inferred from x-ray and nuclear diagnostics for direct-drive inertial confinement fusion cryogenic, layered deuterium-tritium implosions on the 60-beam, 30-kJ, 351-nm OMEGA Laser System. When hydrodynamically scaled to the energy of the National Ignition Facility, these implosions achieved a Lawson parameter ∼60% of the value required for ignition [A. Bose et al.

View Article and Find Full Text PDF

Background: Multiple system atrophy is a rare, fatal neurodegenerative disorder with symptoms of autonomic failure plus parkinsonism, cerebellar ataxia, or both. We report results of the first prospective natural history study of multiple system atrophy in the USA, and the effects of phenotype and autonomic failure on prognosis.

Methods: We recruited participants with probable multiple system atrophy-of either the parkinsonism subtype (MSA-P) or the cerebellar ataxia subtype (MSA-C)-at 12 neurology centres in the USA specialising in movement or autonomic disorders.

View Article and Find Full Text PDF

This Letter presents the first experimental demonstration of the capability to launch shocks of several-hundred Mbar in spherical targets--a milestone for shock ignition [R. Betti et al., Phys.

View Article and Find Full Text PDF

The advent of high-intensity lasers enables us to recreate and study the behaviour of matter under the extreme densities and pressures that exist in many astrophysical objects. It may also enable us to develop a power source based on laser-driven nuclear fusion. Achieving such conditions usually requires a target that is highly uniform and spherically symmetric.

View Article and Find Full Text PDF