162 research outputs found
Properties of LiF and Al_2O_3 to 240 GPa for Metal Shock Temperature Measurements
Shock temperature experiments employing a six-channel pyrometer were conducted on 200, 500, and 1000 A thick films of Fe sandwiched between 3-mm-thick anvils of Al203 and LiF to measure the thermal diffusivity ratios
Al_20_3/Fe and LiF / Fe at high temperatures and pressures. Temperature decays of 3000 ± 800 K in 250 ns were observed at Fe pressures of 194 - 303 GPa, which reflect the conduction of heat from the thin metal films into the anvil material. These results were achieved via experiments employing LiF anvils at conditions of 164 - 165 GPa and 4190 - 4220 K and Al_2O_3 anvils at conditions of 156 - 304 GPa and 1290 - 2740 K. Thermal modeling of interface temperature versus time yields best fit thermal diffusivity
ratios of 4 - 19 ± 1 (Fe/anvil) over the pressure and temperature range of the experiments. Calculated thermal conductivities for Fe, using electron gas theory, of 111 - 181 W /mK are used to calculate thermal conductivities
for the anvil materials ranging from 2 to 13 W /mK. Debye theory predicts higher values of 8 to 35 W /mK. Data from previous experiments on thick (≥l00μm) films of Fe and stainless steel are combined with our present results from experiments on thin (≤1000 A) films to infer a 5860 ± 390
K Hugoniot temperature for the onset of melting of iron at 243 GPa. Our results address the question of whether radiation observed in shock temperature experiments on metals originates from the metal at the metal/anvil
interface or from the shocked anvil. We conclude that the photon flux from the shocked assemblies recorded in all experiments originates from the metal. Within the uncertainties of the shock temperature data, the uncertainties in shock temperatures resulting from the radiation from the anvils is negligible. This is in direct disagreement with the conclusions of previous work by
Kondo
Phase diagram of iron, revised-core temperatures
Shock-wave experiments on iron preheated to 1573 K from 14 to 73 GPa, yield sound velocities of the γ- and liquid-phases. Melting is observed in the highest pressure (∼71 ± 2 GPa) experiments at calculated shock temperatures of 2775 ± 160 K. This single crossing of the γ-liquid boundary agrees with the γ-iron melting line of Boehler [1993], Saxena et al. [1993], and Jephcoat and Besedin [1997]. This γ-iron melting curve is ∼300°C lower than that of Shen et al. [1998] at 80 GPa. In agreement with Brown [2001] the discrepancy between the diamond cell melting data and the iron shock temperatures require the occurrence of yet another sub-solidus phase along the principal Hugoniot at ∼200 GPa. This would reconcile the static and dynamic data for iron's melting curve. Upward pressure and temperature extrapolation of the γ-iron melting curve to 330 GPa yields 5300 ± 400 K for the inner core-outer core boundary temperature
A Model for Hospital Discharge Preparation: From Case Management to Care Transition
There has been a proliferation of initiatives to improve discharge processes and outcomes for the transition from hospital to home and community-based care. Operationalization of these processes has varied widely as hospitals have customized discharge care into innovative roles and functions. This article presents a model for conceptualizing the components of hospital discharge preparation to ensure attention to the full range of processes needed for a comprehensive strategy for hospital discharge
Shock temperatures and the melting point of iron
New measurements of the ratio of Fe to LiF and Al_2O_3 anvil thermal diffusivities are used to obtain revised shock temperatures for Fe. New results match Brown and McQueen’s (1) calculations of the temperatures of 5000 and 5800K at the 200 and 243 GPa transitions in Fe. New sound speed measurements along the Hugoniot of γ-Fe, centered at 1573K, demonstrate that this phase melts at ∼70 GPa and ∼2800 K and the γ phase does not occur above ∼93 GPa. At higher pressures, perhaps over the entire pressure range of the Earth’s molten outer core (132 to 330 GPa), the β (dhcp) phase, and not the ε phase, appears to be the solidus phase of pure Fe
Vaccination Rates and Family Barriers Among Children with Inflammatory Bowel Disease
Background: Many children with inflammatory bowel disease (IBD) are taking immunosuppressant medications that place them at risk for vaccine preventable diseases. Despite national guidelines, children with IBD have low vaccination rates. Adult data suggest that there is concern about the safety of vaccines. There are no current studies addressing perceived safety about vaccinations among families of children with IBD.
Methods: A total of 108 caregivers of children (ages 10-25 years) were surveyed during their outpatient visit, with approximately half having a diagnosis of IBD. The survey consisted of validated questions regarding vaccine safety and opinions. After enrollment, state-wide vaccine registry data was collected. Demographics between the two groups were compared using Ch-square and the Wilcoxon rank-sum tests to analyze Likert scale questions.
Results: The majority of children followed for IBD were Caucasian males, had Crohn's disease (68%) and were immunosuppressed. Results from the survey revealed a concern about vaccine safety (40% vs. 16%, p=0.03) and overall effectiveness (34% vs. 12%, p<0.01) in the IBD group compared to the non-IBD. Furthermore, more IBD families were worried that vaccines would worsen their child's symptoms (36% vs. 10%, p=<0.01). The majority of children were missing the flu and/or HPV vaccine. Finally, 96% of the children on a biologic for their IBD were missing the PPSV23 booster.
Conclusions: Caregivers of children with IBD are more concerned about vaccine safety and effectiveness than those with non-IBD diagnosis. Despite being on immunosuppressant medications, many patients were missing recommended vaccines
Microbial rRNA sequencing analysis of evaporative cooler indoor environments located in the Great Basin Desert region of the United States
Recent studies conducted in the Great Basin Desert region of the United States have shown that skin test reactivity to fungal and dust mite allergens are increased in children with asthma or allergy living in homes with evaporative coolers (EC). The objective of this study was to determine if the increased humidity previously reported in EC homes leads to varying microbial populations compared to homes with air conditioners (AC). Children with physician-diagnosed allergic rhinitis living in EC or AC environments were recruited into the study. Air samples were collected from the child's bedroom for genomic DNA extraction and metagenomic analysis of bacteria and fungi using the Illumina MiSeq sequencing platform. The analysis of bacterial populations revealed no major differences between EC and AC sampling environments. The fungal populations observed in EC homes differed from AC homes. The most prevalent species discovered in AC environments belonged to the genera Cryptococcus (20%) and Aspergillus (20%). In contrast, the most common fungi identified in EC homes belonged to the order Pleosporales and included Alternaria alternata (32%) and Phoma spp. (22%). The variations in fungal populations provide preliminary evidence of the microbial burden children may be exposed to within EC environments in this region
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The Ever-Increasing Array of Novel Inborn Errors of Immunity : an Interim Update by the IUIS Committee
The most recent updated classification of inborn errors of immunity/primary immunodeficiencies, compiled by the International Union of Immunological Societies Expert Committee, was published in January 2020. Within days of completing this report, it was already out of date, evidenced by the frequent publication of genetic variants proposed to cause novel inborn errors of immunity. As the next formal report from the IUIS Expert Committee will not be published until 2022, we felt it important to provide the community with a brief update of recent contributions to the field of inborn errors of immunity. Herein, we highlight studies that have identified 26 additional monogenic gene defects that reach the threshold to represent novel causes of immune defects.Peer reviewe
Human Inborn Errors of Immunity : 2022 Update on the Classification from the International Union of Immunological Societies Expert Committee
We report the updated classification of inborn errors of immunity, compiled by the International Union of Immunological Societies Expert Committee. This report documents the key clinical and laboratory features of 55 novel monogenic gene defects, and 1 phenocopy due to autoantibodies, that have either been discovered since the previous update (published January 2020) or were characterized earlier but have since been confirmed or expanded in subsequent studies. While variants in additional genes associated with immune diseases have been reported in the literature, this update includes only those that the committee assessed that reached the necessary threshold to represent novel inborn errors of immunity. There are now a total of 485 inborn errors of immunity. These advances in discovering the genetic causes of human immune diseases continue to significantly further our understanding of molecular, cellular, and immunological mechanisms of disease pathogenesis, thereby simultaneously enhancing immunological knowledge and improving patient diagnosis and management. This report is designed to serve as a resource for immunologists and geneticists pursuing the molecular diagnosis of individuals with heritable immunological disorders and for the scientific dissection of cellular and molecular mechanisms underlying monogenic and related human immune diseases.Peer reviewe
A randomised controlled trial of supplemental oxygen versus medical air during exercise training in people with chronic obstructive pulmonary disease: Supplemental oxygen in pulmonary rehabilitation trial (SuppORT) (Protocol)
© 2016 Alison et al. Background: Oxygen desaturation during exercise is common in people with chronic obstructive pulmonary disease (COPD). The aim of the study is to determine, in people with COPD who desaturate during exercise, whether supplemental oxygen during an eight-week exercise training program is more effective than medical air (sham intervention) in improving exercise capacity and health-related quality of life both at the completion of training and at six-month follow up. Methods/Design: This is a multi-centre randomised controlled trial with concealed allocation, blinding of participants, exercise trainers and assessors, and intention-to-treat analysis. 110 people with chronic obstructive pulmonary disease who demonstrate oxygen desaturation lower than 90 % during the six-minute walk test will be recruited from pulmonary rehabilitation programs in seven teaching hospitals in Australia. People with chronic obstructive pulmonary disease on long term oxygen therapy will be excluded. After confirmation of eligibility and baseline assessment, participants will be randomised to receive either supplemental oxygen or medical air during an eight-week supervised treadmill and cycle exercise training program, three times per week for eight weeks, in hospital outpatient settings. Primary outcome measures will be endurance walking capacity assessed by the endurance shuttle walk test and health-related quality of life assessed by the Chronic Respiratory Disease Questionnaire. Secondary outcomes will include peak walking capacity measured by the incremental shuttle walk test, dyspnoea via the Dyspnoea-12 questionnaire and physical activity levels measured over seven days using an activity monitor. All outcomes will be measured at baseline, completion of training and at six-month follow up. Discussion: Exercise training is an essential component of pulmonary rehabilitation for people with COPD. This study will determine whether supplemental oxygen during exercise training is more effective than medical air in improving exercise capacity and health-related quality of life in people with COPD who desaturate during exercise. Trial registration: Australian New Zealand Clinical Trials Registry ACTRN12612000395831 , 5th Jan,201
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