Photodissociation of Cl_2O at 248 and 308 nm

Molecular beam studies of Cl_2O photolysis at 248 and 308 nm have been repeated and the analysis refined. At 248 nm, three distinct dissociation pathways that led to Cl+ClO products were resolved. At 308 nm, the angular distribution was slightly more isotropic than previously reported, leaving open the possibility that Cl_2O excited at 308 nm lives longer than a rotational period

Hyperthermal neutral beam etching

A pulsed beam of hyperthermal fluorine atoms with an average translational energy of 4.8 eV has been used to demonstrate anisotropic etching of Si. For 1.4 Hz operation, a room-temperature etch rate of 300 Å/min for Si(100) has been measured at a distance of 30 cm from the source. A 14% undercutting for room-temperature etching of Novolac-masked Si features was achieved under single-collision conditions, with no detectable mask erosion. Translational energy and angular distributions of scattered fluorine atoms during steady-state etching of Si by a normal-incidence, collimated beam demonstrate that unreacted F atoms can scatter inelastically, retaining a significant fraction of their initial kinetic energies. The observed undercutting can be explained by secondary impingement of these high-energy F atoms, which are more reactive upon interaction with the sidewalls than would be expected if they desorbed from the surface at thermal energies after full accommodation. Time-of-flight distributions of volatile reaction products were also collected, and they show evidence for a dominant nonthermal reaction mechanism of the incident atoms with the surface in addition to a thermal reaction channel

Dissociation Dynamics of CIONO_2 and Relative Cl and ClO Product Yields following Photoexcitation at 308 nm

Chlorine nitrate photolysis at 308 nm has been investigated with a molecular beam technique. Two primary decomposition pathways, leading to Cl + NO_3 and ClO + NO_2, were observed. The branching ratio between these two respective channels was determined to be 0.67 ± 0.06 : 0.33 ± 0.06. This ratio is an upper limit because some of the ClO photoproducts may have undergone secondary photodissociation. The angular distributions of the photoproducts with respect to the direction of polarization of the exciting light were anisotropic. The anisotropy parameters were β= 0.5 ± 0.2 for the Cl + NO_3 channel and β= 1.1 ± 0.2 for the ClO + NO_2 channel, indicating that dissociation of ClONO_2 by either pathway occurs within a rotational period. Weak signal at mass-to-charge ratios of 35 and 51, arising from products with laboratory velocities close to the beam velocity, was observed. While this signal could result from statistical dissociation channels with a total relative yield of 0.07 or less, it is more likely attributable to products from ClO secondary photodissociation or from dissociation of clusters

Primary and secondary dissociation pathways in the ultraviolet photolysis of Cl_2O

The photodissociation of dichlorine monoxide (Cl_2O) at 308, 248, and 193 nm was studied by photofragment translational energy spectroscopy. The primary channel upon excitation at 308 and 248 nm was Cl–O bond fission with production of ClO+Cl. A fraction of the ClO photoproducts also underwent spontaneous secondary dissociation at 248 nm. The center-of-mass translational energy distribution for the ClO+Cl channel at 248 nm appeared to be bimodal with a high energy component that was similar in shape to the 308 nm distribution and a second, low energy component with a maximum close to the threshold for the 2Cl+O(3P) channel. Observation of a bimodal distribution suggests that two pathways with different dissociation dynamics lead to ClO+Cl products. The high product internal energy of the second component raises the possibility that ClO is formed in a previously unobserved spin-excited state a 4∑−. Following excitation at 193 nm, a concerted dissociation pathway leading to Cl_2+O was observed in addition to primary Cl–O bond breakage. In both processes, most of the diatomic photofragments were formed with sufficient internal energy that they spontaneously dissociated. The time-of-flight distributions of the Cl_2+O products suggest that these fragments are formed in two different channels Cl_2(3II)+O(3P) and Cl_2(X1∑)+O(1D)

Molecular beam scattering from C-13 enriched Kapton and correlation with the EOIM-3 carousel experiment

Mass spectra of products emerging from identical samples of a C-13-enriched polyimide polymer (chemically equivalent to Kapton) under atomic oxygen bombardment in space and in the laboratory were collected. Reaction products unambiguously detected in space were CO-13, NO, (12)CO2, and (13)CO2. These reaction products and two others, H2O and CO-12, were detected in the laboratory, along with inelastically scattered atomic and molecular oxygen. Qualitative agreement was seen in the mass spectra taken in space and in the laboratory; the agreement may be improved by reducing the fraction of O2 in the laboratory molecular beam. Both laboratory and space data indicated that CO and CO2 products come preferentially from reaction with the imide component of the polymer chain, raising the possibility that the either component may degrade in part by the 'evaporation' of higher molecular weight fragments. Laboratory time-of-flight distributions showed: (1) incomplete energy accommodation of impinging O and O2 species that do not react with the surface; and (2) both hyperthermal and thermal CO and CO2 products, suggesting two distinct reaction mechanisms with the surface

Dead cetacean? beach, bloat, float, sink

© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Moore, M. J., Mitchell, G. H., Rowles, T. K., & Early, G. Dead cetacean? beach, bloat, float, sink. Frontiers in Marine Science, 7, (2020): 333, doi:10.3389/fmars.2020.00333.Variably buoyant, dead Cetacea may float, or sink and later bloat to refloat if ambient temperature and pressure allow sufficient decomposition gas formation and expansion. Mortality can result from acute or chronic disease, fishery entanglement, vessel collision, noxious noises, or toxicant spills. Investigators often face the daunting task of elucidating a complex series of events, in reverse order, from when and where an animal is found, and to diagnose the cause of death. Various scenarios are possible: an animal could die at sea remaining there or floating ashore, or strand on a beach alive, where it dies and, if cast high enough, remain beached to be scavenged or decompose. An animal that rests low on a beach may refloat again, through increased buoyancy from decomposition gas and favorable tides, currents, and wind. Here we review the factors responsible for the different outcomes, and how to recognize the provenance of a cetacean mortality found beached, or floating at sea. In conclusion, only some carcasses strand, or remain floating. Negatively buoyant animals that die at depth, or on the surface, and sink, may never surface, even after decomposition gas accumulation, as in cold, deep waters gas may fail to adequately reduce the density of a carcass, precluding it from returning to the surface

Rapidly Progressive Malignant Rhabdoid Tumor of the Omentum in an Adult. A Case Report and Review of the Literature

Introduction: Malignant Rhabdoid Tumors (MRT) are exceedingly rare neoplasms that characteristically occur in infants and children and sparsely develop in adults. Primary MRTs of the omentum are particularly rare.Presentation of Case: A previously healthy 24-year-old male who presented with progressive abdominal distention and nausea. Further investigations revealed ascites with multifocal omental-based tumors. Biopsy with immunohistochemistry demonstrated dually positive cells for cytokeratin and vimentin and loss of Integrase Interactor 1 (INI1), and Next generation sequencing showed a copy number loss of SMARCB1 which established the diagnosis of malignant rhabdoid tumor. The patient’s clinical course was characterized by rapid local and metastatic progression with subsequent clinical deterioration, and he expired within three weeks of his initial presentation.Conclusion: Herein we describe the clinical course, difficulty with diagnosis, and paucity of treatment options for a rare and very aggressive malignant tumor. The ideal treatment regimen for MRTs has yet to be elucidated and additional studies are required to discern therapies that offer benefit

A Completely New Type of Actuator -or- This Ain't Your Grandfather's Internal Combustion Engine

A completely new type of actuator - one that is proposed for use in a variety of environments from sea to land to air to space - has been designed, patented, built, and tested. The actuator is loosely based on the principle of the internal combustion engine, except that it is a completely closed system, only requiring electrical input, and the working fuel is water. This paper outlines the theory behind the electrolysis- and ignition-based cycle upon which the actuator operates and describes the performance capability test apparatus and results for the actuator. A mechanism application that harnessed the unit s power to twist a scaled rotor blade is also highlighted

Long-term evaluation of a hospital-based violence intervention program using a regional health information exchange

BACKGROUND: Hospital-based violence intervention programs (HVIP) aim to reduce violent-injury recidivism by providing intensive case management services to high-risk patients who were violently injured. Although HVIP have been found effective at reducing recidivism, few studies have sought to identity how long their effects last. Additionally, prior studies have been limited by the fact that HVIP typically rely on self-report or data within their own healthcare system to identify new injuries. Our aim was to quantify the long-term recidivism rate of participants in an HVIP program using more objective and comprehensive data from a regional health information exchange. METHODS: The study included 328 patients enrolled in Prescription for Hope (RxH), an HVIP, between January 2009 and August 2016. We obtained RxH participants' emergency department (ED) encounter data from a regional health information exchange database from the date of hospital discharge to February 2017. Our primary outcome was violent-injury recidivism rate of the RxH program. We also examined reasons for ED visits that were unrelated to violent injury. RESULTS: We calculated a 4.4% recidivism rate based on 8 years of statewide data, containing 1,575 unique encounters. More than 96% of participants were matched in the state database. Of the 15 patients who recidivated, only five were admitted for their injury. More than half of new violence-related injuries were treated outside of the HVIP-affiliated trauma center. The most common reasons for ED visits were pain (718 encounters), followed by suspected complications or needing additional postoperative care (181 encounters). Substance abuse, unintentional injuries, and suicidal ideation were also frequent reasons for ED visits. CONCLUSION: The low, long-term recidivism rate for RxH indicates that HVIPs have enduring positive effects on the majority of participants. Our results suggest that HVIP may further benefit patients by partnering with organizations that work to prevent suicide, substance use disorders, and other unintentional injuries. LEVEL OF EVIDENCE: Therapeutic study, level III

An assessment of sampling biases across studies of diel activity patterns in marine ray-finned fishes (Actinopterygii)

Author Posting. © University of Miami - Rosenstiel School of Marine and Atmospheric Science, 2016. This article is posted here by permission of University of Miami - Rosenstiel School of Marine and Atmospheric Science for personal use, not for redistribution. The definitive version was published in Bulletin of Marine Science 93 (2017): 611-639, doi:10.5343/bms.2016.1016.Understanding the promotion and regulation of circadian rhythms in marine fishes is important for studies spanning conservation, evolutionary biology, and physiology. Given numerous challenges inherent to quantifying behavioral activity across the full spectrum of marine environments and fish biodiversity, case studies offer a tractable means of gaining insights or forecasting broad patterns of diel activity. As these studies continue to accumulate, assessing whether, and to what extent, the cumulatively collected data are biased in terms of geography, habitat, or taxa represents a fundamentally important step in the development of a broad overview of circadian rhythms in marine fish. As such investigations require a phylogenetic framework, general trends in the phylogenetic sampling of marine fishes should be simultaneously assessed for biases in the sampling of taxa and trait data. Here, we compile diel activity data for more than 800 marine species from more than five decades of scientific studies to assess general patterns of bias. We found significant geographic biases that largely reflect a preference toward sampling warm tropical waters. Additionally, taxonomic biases likewise reflect a tendency toward conspicuous reef associated clades. Placing these data into a phylogenetic framework that includes all known marine fishes revealed significant under-dispersion of behavioral data and taxon sampling across the whole tree, with a few subclades exhibiting significant over-dispersion. In total, our study illuminates substantial gaps in our understanding of diel activity patterns and highlights significant sampling biases that have the potential to mislead evolutionary or ecological analyses.Partial funding was provided by the North Carolina Museum of Natural Sciences