Instrument design for an inertial confinement fusion ion temperature imager

A mix of contaminant mass is a known, performance-limiting factor for laser-driven inertial confinement fusion (ICF). It has also recently been shown that the contaminant mass is not necessarily in thermal equilibrium with the deuterium-tritium plasma [B. M. Haines et al., Nat. Commun. 11, 544 (2020)]. Contaminant mass temperature is one of the dominant uncertainties in contaminant mass estimates. The MixIT diagnostic is a new and potentially transformative diagnostic, capable of spatially resolving ion temperature. The approach combines principles of neutron time-of-flight and neutron imaging diagnostics. The information from the MixIT diagnostic can be used to optimize ICF target and laser drive designs as well as provide key constraints on ICF radiation-hydrodynamic simulations that are critical to contaminant mass estimates. This work details the design and optimization of the major components of the MixIT diagnostic: the neutron aperture, the neutron detector (scintillator), and the recording system.

Design of multi neutron-to-gamma converter array for measuring time resolved ion temperature of inertial confinement fusion implosions

The ion temperature varying during inertial confinement fusion implosions changes the amount of Doppler broadening of the fusion products, creating subtle changes in the fusion neutron pulse as it moves away from the implosion. A diagnostic design to try to measure these subtle effects is introduced-leveraging the fast time resolution of gas Cherenkov detectors along with a multi-puck array that converts a small amount of the neutron pulse into gamma-rays, one can measure multiple snapshots of the neutron pulse at intermediate distances. Precise measurements of the propagating neutron pulse, specifically the variation in the peak location and the skew, could be used to infer time-evolved ion temperature evolved during peak compression.

Monitoring SARS-CoV-2 decontamination by dry heat and ultraviolet treatment with a swine coronavirus as a surrogate

The critical need for reliable methods to validate decontamination protocols for personal protective equipment (PPE) for re-use during the SARS-CoV-2 pandemic is limited by the need for specialized containment facilities to handle the virus. Hence, we have herein validated the use of a swine coronavirus as a surrogate, and tested the effectiveness of dry heat and ultraviolet (UV) rays for PPE decontamination. Exposure of experimentally contaminated N95 masks and hospital gowns to 60°C for 20 min, and UVC at 1800 mJ/cm² resulted in a 4-log reduction and inactivation of the surrogate virus. This study provides a novel alternative to validate PPE reprocessing methods.

Biosynthesis of sphinganine-analog mycotoxins

Sphinganine-analog mycotoxins (SAMT) are polyketide-derived natural products produced by a number of plant pathogenic fungi and are among the most economically important mycotoxins. The toxins are structurally similar to sphinganine, a key intermediate in the biosynthesis of ceramides and sphingolipids, and competitive inhibitors for ceramide synthase. The inhibition of ceramide and sphingolipid biosynthesis is associated with several fatal diseases in domestic animals and esophageal cancer and neural tube defects in humans. SAMT contains a highly reduced, acyclic polyketide carbon backbone, which is assembled by a single module polyketide synthase. The biosynthesis of SAMT involves a unique polyketide chain-releasing mechanism, in which a pyridoxal 5'-phosphate-dependent enzyme catalyzes the termination, offloading and elongation of the polyketide chain. This leads to the introduction of a new carbon-carbon bond and an amino group to the polyketide chain. The mechanism is fundamentally different from the thioesterase/cyclase-catalyzed polyketide chain releasing found in bacterial and other fungal polyketide biosynthesis. Genetic data suggest that the ketosynthase domain of the polyketide synthase and the chain-releasing enzyme are important for controlling the final product structure. In addition, several post-polyketide modifications have to take place before SAMT become mature toxins.

Body mass and individual fitness in female ungulates: bigger is not always better

In female vertebrates, differences in fitness often correspond to differences in phenotypic quality, suggesting that larger females have greater fitness. Variation in individual fitness can result from variation in life span and/or variation in yearly reproductive success, but no study has yet assessed the relationships between the components of fitness and phenotypic quality while controlling for life span. We tried to fill this gap using data from long-term monitoring (23 years) of marked roe deer and bighorn sheep, two ungulates with very different life histories. In both species, we found a strong positive relationship between an adult female's mass and her probability of reaching old age: over the long term, bigger is indeed better for ungulate females. On the other hand, we found no evidence in either species that heavier females had higher fitness when differences in life span were accounted for: over the short term, bigger is not necessarily better. Our results indicate that, while broad differences in phenotypic quality affect individual fitness, when differences in life span are accounted for phenotypic quality has no residual effect on fitness. Therefore, within a given range of phenotypic quality, bigger is not always better, for reasons which may differ between species.

Therapeutic use of companion animals in health care

PURPOSE

To explore research that lends credibility to the therapeutic use of animals in health care. By integrating research from other disciplines and applying it to nursing, the art of nursing is fostered through the creative application of knowledge to practice.

SIGNIFICANCE

Positive physiological and psychological benefits have been linked to the presence of companion animals. For example, researchers suggest that decreases in blood pressure, heart rates, and stress levels, as well as increases in emotional well-being and social interaction are benefits of the human-animal bond.

CONCLUSIONS

Compiling what has been learned in earlier scientific studies provides direction for future research in nursing to enhance nursing knowledge and expand nursing theory to improve care. Further investigation is necessary to clarify the concepts of animal assisted therapy (AAT) to build a body of useful knowledge for practice.

Bacteremia associated with operative decompression of a small bowel obstruction

BACKGROUND

Intraoperative decompression of the small bowel has been advocated as a method of aiding recovery of both the patient and the intestine. However, the methods proposed (retrograde stripping or enterotomy) require vigorous handling of bacteria-laden small bowel, possibly giving rise to a bacteremia.

STUDY DESIGN

A small bowel obstruction was created in 31 rats by means of a ligature. Twenty-four hours later, the obstruction was relieved, and the rats were divided into three groups: relief of obstruction alone, relief with retrograde stripping, and relief with enterotomy plus suction. Blood cultures were taken before and after manipulation of the bowel.

RESULTS

In blood cultures taken before and after manipulation there was a significant increase of Escherichia coli bacteremia in the two manipulation groups compared with the relief of obstruction only group.

CONCLUSIONS

Bacteremia may be an effect of operative decompression of obstructed bowel, which at times outweighs its supposed benefits.