23 research outputs found
Enhanced ultrafast X-ray diffraction by transient resonances
Diffraction-before-destruction imaging with single ultrashort X-ray pulses
has the potential to visualise non-equilibrium processes, such as chemical
reactions, at the nanoscale with sub-femtosecond resolution in the native
environment without the need of crystallization. Here, a nanospecimen partially
diffracts a single X-ray flash before sample damage occurs. The structural
information of the sample can be reconstructed from the coherent X-ray
interference image. State-of-art spatial resolution of such snapshots from
individual heavy element nanoparticles is limited to a few nanometers. Further
improvement of spatial resolution requires higher image brightness which is
ultimately limited by bleaching effects of the sample. We compared snapshots
from individual 100 nm Xe nanoparticles as a function of the X-ray pulse
duration and incoming X-ray intensity in the vicinity of the Xe M-shell
resonance. Surprisingly, images recorded with few femtosecond and
sub-femtosecond pulses are up to 10 times brighter than the static linear model
predicts. Our Monte-Carlo simulation and statistical analysis of the entire
data set confirms these findings and attributes the effect to transient
resonances. Our simulation suggests that ultrafast form factor changes during
the exposure can increase the brightness of X-ray images by several orders of
magnitude. Our study guides the way towards imaging with unprecedented
combination of spatial and temporal resolution at the nanoscale
Partisans Without Constraint: Political Polarization and Trends in American Public Opinion
Three-year follow-up of prospective trial of focused ultrasound thalamotomy for essential tremor.
OBJECTIVE: To test the hypothesis that transcranial magnetic resonance-guided focused ultrasound (tcMRgFUS) thalamotomy is effective, durable, and safe for patients with medication-refractory essential tremor (ET), we assessed clinical outcomes at 3-year follow-up of a controlled multicenter prospective trial.
METHODS: Outcomes were based on the Clinical Rating Scale for Tremor, including hand combined tremor-motor (scale of 0-32), functional disability (scale of 0-32), and postural tremor (scale of 0-4) scores, and total scores from the Quality of Life in Essential Tremor Questionnaire (scale of 0-100). Scores at 36 months were compared with baseline and at 6 months after treatment to assess for efficacy and durability. Adverse events were also reported.
RESULTS: Measured scores remained improved from baseline to 36 months (all
CONCLUSIONS: Results at 3 years after unilateral tcMRgFUS thalamotomy for ET show continued benefit, and no progressive or delayed complications. Patients may experience mild degradation in some treatment metrics by 3 years, though improvement from baseline remains significant.
CLINICALTRIALSGOV IDENTIFIER: NCT01827904.
CLASSIFICATION OF EVIDENCE: This study provides Class IV evidence that for patients with severe ET, unilateral tcMRgFUS thalamotomy provides durable benefit after 3 years
A Pilot Study Using Next-Generation Sequencing in Advanced Cancers: Feasibility and Challenges
<div><p>Purpose</p><p>New anticancer agents that target a single cell surface receptor, up-regulated or amplified gene product, or mutated gene, have met with some success in treating advanced cancers. However, patients' tumors still eventually progress on these therapies. If it were possible to identify a larger number of targetable vulnerabilities in an individual's tumor, multiple targets could be exploited with the use of specific therapeutic agents, thus possibly giving the patient viable therapeutic alternatives.</p><p>Experimental Design</p><p>In this exploratory study, we used next-generation sequencing technologies (NGS) including whole genome sequencing (WGS), and where feasible, whole transcriptome sequencing (WTS) to identify genomic events and associated expression changes in advanced cancer patients.</p><p>Results</p><p>WGS on paired tumor and normal samples from nine advanced cancer patients and WTS on six of these patients' tumors was completed. One patient's treatment was based on targets and pathways identified by NGS and the patient had a short-lived PET/CT response with a significant reduction in his tumor-related pain. To design treatment plans based on information garnered from NGS, several challenges were encountered: NGS reporting delays, communication of results to out-of-state participants and their treating oncologists, and chain of custody handling for fresh biopsy samples for Clinical Laboratory Improvement Amendments (CLIA) target validation.</p><p>Conclusion</p><p>While the initial effort was a slower process than anticipated due to a variety of issues, we demonstrate the feasibility of using NGS in advanced cancer patients so that treatments for patients with progressing tumors may be improved.</p></div