A TOPAS model for lens-based proton radiography.

Proton Radiography can be used in conjunction with proton therapy for patient positioning, real-time estimates of stopping power, and adaptive therapy in regions with motion. The modeling capability shown here can be used to evaluate lens-based radiography as an instantaneous proton-based radiographic technique. The utilization of user-friendly Monte Carlo program TOPAS enables collaborators and other users to easily conduct medical- and therapy- based simulations of the Los Alamos Neutron Science Center (LANSCE).

Use of next-generation sequencing to detect mutations associated with antiviral drug resistance in cytomegalovirus.

Cytomegalovirus (CMV) is a significant cause of morbidity and mortality among immunocompromised hosts, including transplant recipients. Antiviral prophylaxis or treatment is used to reduce the incidence of CMV disease in this patient population; however, there is concern about increasing antiviral resistance. Detection of antiviral resistance in CMV was traditionally accomplished using Sanger sequencing of and genes, in which specific mutations may result in reduced antiviral activity.

Benefits of symbiotic ectomycorrhizal fungi to plant water relations depend on plant genotype in pinyon pine.

Rhizosphere microbes, such as root-associated fungi, can improve plant access to soil resources, affecting plant health, productivity, and stress tolerance. While mycorrhizal associations are ubiquitous, plant-microbe interactions can be species specific. Here we show that the specificity of the effects of microbial symbionts on plant function can go beyond species level: colonization of roots by ectomycorrhizal fungi (EMF) of the genus Geopora has opposite effects on water uptake, and stomatal control of desiccation in drought tolerant and intolerant genotypes of pinyon pine (Pinus edulis Engelm.

Quantitation of Nuclear Magnetic Resonance Spectra at Earth's Magnetic Field.

The inherently quantitative nature of nuclear magnetic resonance (NMR) spectroscopy is one of the most attractive aspects of this analytical technique. Quantitative NMR analyses have typically been limited to high-field (>1 T) applications. The aspects for quantitation at low magnetic fields (<1 mT) have not been thoroughly investigated and are shown to be impacted by the complex signatures that arise at these fields from strong heteronuclear -couplings.

Contrast-enhanced proton radiographic sensitivity limits for tumor detection.

Proton radiography may guide proton therapy cancer treatments with beam's-eye-view anatomical images and a proton-based estimation of proton stopping power. However, without contrast enhancement, proton radiography will not be able to distinguish tumor from tissue. To provide this contrast, functionalized, high- nanoparticles that specifically target a tumor could be injected into a patient before imaging.

Spectral characterization of flash and high flux x-ray radiographic sources with a magnetic Compton spectrometer.

In this work, we present a new analysis method applied to revitalize permanent magnet Compton spectrometers used to measure photon energy spectra in the MeV range. The inversion of the measured electron distribution to determine the original photon distribution is achieved via a method of consistent coupled radiation transport and magnetic field mapping of the input photon spectra to the measured electron distribution. The method of linear least squares was used to perform the unfolding of the electron distribution to the initial photon spectra, without any assumptions made regarding the electron distribution.

The H T dispersion curve of fentanyl citrate to identify NQR parameters.

We report the H T dispersion curve between 0 and 5 ​MHz for the synthetic opioid fentanyl citrate (CHNO). The structures in the curve can be used to estimate the N nuclear quadrupole resonance (NQR) frequencies of the material. Density functional theory predictions of the NQR parameters of several fentanyl citrate compounds are also reported.

Design and implementation of a J-coupled spectrometer for multidimensional structure and relaxation detection at low magnetic fields.

In recent years, it has been realized that low and ultra-low field (mT-nT magnetic field range) nuclear magnetic resonance spectroscopy can be used for molecular structural analysis. However, spectra are often hindered by lengthy acquisition times or require large sample volumes and high concentrations. Here, we report a low field (50 μT) instrument that employs a linear actuator to shuttle samples between a 1 T prepolarization field and a solenoid detector in a laboratory setting.

On a Method For Reconstructing Computed Tomography Datasets from an Unstable Source.

As work continues in neutron computed tomography, at Los Alamos Neutron Science Center (LANSCE) and other locations, source reliability over the long imaging times is an issue of increasing importance. Moreover, given the time commitment involved in a single neutron image, it is impractical to simply discard a scan and restart in the event of beam instability. In order to mitigate the cost and time associated with these options, strategies are presented in the current work to produce a successful reconstruction of computed tomography data from an unstable source.

Correction of Factor Effects for Simultaneous Collection of Elemental Analysis and Relaxation Times by Nuclear Magnetic Resonance.

A new method for measurement of elemental analysis by nuclear magnetic resonance (NMR) of unknown samples is discussed here as a quick and robust means to measure elemental ratios without the use of internal or external calibration standards. The determination of elemental ratios was done by normalizing the signal intensities by the frequency dependent quality factor () and the gyromagnetic ratios (γ) for each measured nucleus. The correction for the frequency dependence was found by characterizing the output signal of the probe as a function of the quality factor () and the frequency, and the correction for γ was discussed in a previous study.

Neurosensory and Sinus Evolution as Tyrannosauroid Dinosaurs Developed Giant Size: Insight from the Endocranial Anatomy of Bistahieversor sealeyi.

Tyrannosaurus rex and other tyrannosaurid dinosaurs were apex predators during the latest Cretaceous, which combined giant size and advanced neurosensory systems. Computed tomography (CT) data have shown that tyrannosaurids had a trademark system of a large brain, large olfactory bulbs, elongate cochlear ducts, and expansive endocranial sinuses surrounding the brain and sense organs. Older, smaller tyrannosauroid relatives of tyrannosaurids developed some, but not all, of these features, raising the hypothesis that tyrannosaurid-style brains evolved before the enlarged tyrannosaurid-style sinuses, which might have developed only with large body size.

Assessment of Test Performance and Potential for Environmental Contamination Associated with a Point-of-Care Molecular Assay for Group A in an End User Setting.

Although U.S. Food and Drug Administration-approved and CLIA-waived point-of-care (POC) molecular systems are being implemented in routine clinical practice, instrument reliability, test performance in the hands of end users, and the potential for environmental contamination resulting from use of POC molecular systems have not been extensively evaluated.

Calibration of two compact permanent magnet spectrometers for high current electron linear induction accelerators.

In this work, two compact, permanent magnet, electron spectrometers have been built to measure the electron beam energy at the Dual Axis Radiographic Hydrodynamic Test facility. Using H and OH anions, the spectrometers were calibrated at the Special Technologies Laboratory in Santa Barbara, California (USA). The spectrometers were mounted on a custom drift tube that allows the magnet assemblies to be translated, which increases the path length of the electrons traveling through the magnetic field and therefore increases the upper bound of the measurable electron kinetic energy.

Presence of immune deficiency increases the risk of hospitalization in patients with norovirus infection.

Norovirus is an emerging pathogen causing gastroenteritis. We sought to identify factors associated with clinical outcomes in a cohort of patients with laboratory-confirmed norovirus infection. We performed a retrospective chart review of patients with positive norovirus polymerase chain reaction in stool between October 1, 2015, and May 31, 2016.

An Assessment of the AdenoPlus Point-of-Care Test for Diagnosing Adenoviral Conjunctivitis and Its Effect on Antibiotic Stewardship.

Objective: To determine the sensitivity and specificity of the AdenoPlus test compared with real-time polymerase chain reaction (PCR) and to determine whether there was a reduction in antibiotic prescriptions with the use of AdenoPlus compared with the previous year.

Patients And Methods: A total of 125 patients with suspected infectious conjunctivitis were accrued from June 4, 2015, through September 27, 2015. Forty-six participants from the prospective cohort completed both AdenoPlus and PCR testing.

Laser-plasmas in the relativistic-transparency regime: Science and applications.

Laser-plasma interactions in the novel regime of relativistically induced transparency (RIT) have been harnessed to generate intense ion beams efficiently with average energies exceeding 10 MeV/nucleon (>100 MeV for protons) at "table-top" scales in experiments at the LANL Trident Laser. By further optimization of the laser and target, the RIT regime has been extended into a self-organized plasma mode. This mode yields an ion beam with much narrower energy spread while maintaining high ion energy and conversion efficiency.

Automated processing, extraction and detection of herpes simplex virus types 1 and 2: A comparative evaluation of three commercial platforms using clinical specimens.

Background: Recently, automated platforms have been developed that can perform processing, extraction and testing for herpes simplex virus (HSV) nucleic acid on a single instrument.

Objectives: In this study, we compared three commercially-available systems; Aptima/Panther (Hologic, San Diego, CA), ARIES (Luminex Corporation, Austin, TX), and cobas 4800 (Roche Molecular Systems Inc, Pleasanton, CA) for the qualitative detection of HSV-1/2 in clinical samples.

Study Design: Two-hundred seventy-seven specimens (genital [n=193], dermal [n=84]) were submitted for routine HSV-1/2 real-time PCR by a laboratory developed test.

Detection and differentiation of norovirus genogroups I and II from clinical stool specimens using real-time PCR.

A real-time RT-PCR assay was designed to detect and differentiate norovirus genogroups I (GI) and II (GII), with primers and probes targeting the nonstructural polyprotein gene. Stool samples (n = 100) submitted for routine testing by the BioFire FilmArray® GI panel were also tested by the norovirus GI/GII real-time PCR assays. When compared to the FilmArray GI panel, the norovirus real-time PCR assay demonstrated a sensitivity of 77.

Comparison of polystyrene scintillator fiber array and monolithic polystyrene for neutron imaging and radiography.

The neutron imaging diagnostic at the National Ignition Facility has been operating since 2011 generating neutron images of deuterium-tritium (DT) implosions at peak compression. The current design features a scintillating fiber array, which allows for high imaging resolution to discern small-scale structure within the implosion. In recent years, it has become clear that additional neutron imaging systems need to be constructed in order to provide 3D reconstructions of the DT source and these additional views need to be on a shorter line of sight.

Detection of high-risk human papillomavirus infection in tonsillar specimens using 2 commercially available assays.

THE OBJECTIVE OF THE STUDY IS TO DETERMINE THE PREVALENCE OF HIGH-RISK HUMAN PAPILLOMAVIRUS (HRHPV) INFECTION IN TONSILLAR SWABS AND TISSUE: Patients undergoing tonsillectomy for nonmalignant causes were enrolled. A flocked swab and fresh tissue were collected from the left and right tonsil of each patient. Specimens were tested for hrHPV DNA using the Roche cobas test and for the presence of E6/E7 messenger RNA using the Hologic Aptima hrHPV test.

In vivo Observation of Tree Drought Response with Low-Field NMR and Neutron Imaging.

Using a simple low-field NMR system, we monitored water content in a living tree in a greenhouse over 2 months. By continuously running the system, we observed changes in tree water content on a scale of half an hour. The data showed a diurnal change in water content consistent both with previous NMR and biological observations.

Testing for Herpes Simplex Virus in Low-Volume Cerebrospinal Fluid Samples: Comparison of Three Protocols To Optimize Detection.

Detection of herpes simplex virus 1 and 2 (HSV-1 and HSV-2) in cerebrospinal fluid (CSF) is a medical emergency and requires rapid, sensitive testing. However, the volume of CSF received for microbiological studies may be limited, especially from young children. In this study, we compared three testing protocols to our routine real-time PCR method to determine the most sensitive approach for detecting HSV-1 and HSV-2 in low-volume (≤100 μl) CSF.

Direct Detection of Influenza A and B Viruses in Less Than 20 Minutes Using a Commercially Available Rapid PCR Assay.

We compared an FDA-cleared rapid (<20 min) PCR assay (Cobas Liat; Roche Diagnostics) to our routine influenza A and B real-time PCR assay (Simplexa Flu A/B & RSV Direct; Focus Diagnostics) using respiratory swabs (n = 197). The Cobas Liat influenza A and B assays demonstrated sensitivities of 99.2% (123/124) and 100% (23/23), respectively, while showing a specificity of 100% for each target.