Nonequilibrium electrical conductivity measurements in argon and helium seeded plasmas

In a previous paper, the authors presented experimental values of electrical conductivity measured in a plasma composed of argon gas seeded with potassium vapor. The measurements were made at atmospheric pressure with a neutral gas temperature of 2000° ± 100°K and with a number of values of seed concentration in the range 0.2 to 0.8 mole %. The effect of nonequilibrium heating of the electron gas-excited potassium system was investigated for a range of current densities between 0.8 and 80 amp/cm^2. These data were in good agreement with values of the conductivity calculated by a scheme, outlined in Ref. 1, which included the effects of energy loss from the system, composed of the electron gas and the electronically excited states of potassium due to radiation from the excited potassium atoms. In addition, the pulsed technique used to measure the conductivity in response to a step function application of the electric field made possible the determination of the relaxation times for the ionization process

Recombination, ionization, and nonequilibrium electrical conductivity in seeded plasmas

New data are presented which provide direct experimental confirmation of the validity of a physical model which has been widely employed to predict the electrical conductivity of dense, two-temperature, seeded plasmas. Experimental measurements of electron temperature, and ionization and recombination rates are presented for partially ionized plasmas of potassium-seeded argon. Experimental conditions were chosen to cover those ranges of interest in connection with proposed magnetohydrodynamic energy conversion devices for which nonequilibrium electrical conductivity measurements have been previously reported, e.g., translational atom temperatures of about 2000°K, total atom densities near 10^(18)/cm^3, potassium densities of about 10^(16)/cm^3, electron densities from 10^(13)/cm^3 to 10^(15)/cm^3, and electron temperatures from 2200 to 3500°K. Measured values of electron-electron-ion recombination coefficients for potassium show good agreement with theoretical values based upon the Gryzinski classical inelastic-collision cross-section expressions. Observed ionization rates and relaxation characteristics appear to be adequately explained by a similar formulation for the ionization process

How accessible are interpreter services to dialysis patients of Non-English Speaking Background?

Background. Benefits of utilising professional interpreters in clinical settings have been well documented. However, not many studies have focused on use of professional interpreters by dialysis patients of Non-English Speaking Background (NESB) who are in the clinical settings every second day of their lives. The underlying question for this research was to determine the level of interpreter utilisation by dialysis patients of NESB at a major urban teaching hospital. Method. A multi-method approach was used involving (a) in-depth interviews of health care professionals working with dialysis patients to elicit their views regarding interpreter access and use by dialysis patients of NESB, (b) observations of interactions between staff and dialysis patients of NESB and (c) review of medical records belonging to dialysis patients of NESB who were admitted 24 months prior to the study.Results. Interviews revealed that only 50% of Health Care Workers (HCWs) had accessed an interpreter for dialysis patients of NESB over a period of six months. Observations of staff/NESB patient interactions showed that professional interpreters were used in only 25% of the observed occasions. There view of medical records revealed that there was no evidence of interpreter use in 32% of the records belonging to dialysis patients of NESB. The study also showed that non-compliance with dialysis treatment regime was more likely to occur among patients who had limited access to interpreters. Conclusion. The study demonstrated a suboptimal utilisation of interpreter services by dialysis patients of NESB. Several barriers to inaccessibility and underutilisation of professional interpreters were identified. Recommendations to improve communication between HCWs and dialysis patients of NESB are suggested

Interleukin-17A upregulates receptor activator of NF-kappaB on osteoclast precursors.

IntroductionThe interaction between the immune and skeletal systems is evidenced by the bone loss observed in autoimmune diseases such as rheumatoid arthritis. In this paper we describe a new mechanism by which the immune cytokine IL-17A directly affects osteoclastogenesis.MethodsHuman CD14+ cells were isolated from healthy donors, cultured on dentine slices and coverslips and stimulated with IL-17A and/or receptor activator of NF-kappaB ligand (RANKL). Osteoclast differentiation was evaluated by gene expression, flow cytometry, tartrate-resistant acid phosphatase staining, fluorescence and electron microscopy. Physiologic bone remodelling was studied in wild-type (Wt) and IL-17A-/- mice using micro-computer tomography and serum RANKL/osteoprotegerin concentration. Functional osteoclastogenesis assays were performed using bone marrow macrophages isolated from IL-17A-/- and Wt mice.ResultsIL-17A upregulates the receptor activator for NF-kappaB receptor on human osteoclast precursors in vitro, leading to increased sensitivity to RANKL signalling, osteoclast differentiation and bone loss. IL-17A-/- mice have physiological bone homeostasis indistinguishable from Wt mice, and bone marrow macrophages isolated from these mice develop fully functional normal osteoclasts.ConclusionsCollectively our data demonstrate anti-IL-17A treatment as a selective therapeutic target for bone loss associated with autoimmune diseases

Myeloid DAP12-associating lectin (MDL)-1 regulates synovial inflammation and bone erosion associated with autoimmune arthritis.

DNAX adaptor protein 12 (DAP12) is a trans-membrane adaptor molecule that transduces activating signals in NK and myeloid cells. Absence of functional Dap12 results in osteoclast defects and bone abnormalities. Because DAP12 has no extracelluar binding domains, it must pair with cell surface receptors for signal transduction. There are at least 15 known DAP12-associating cell surface receptors with distinct temporal and cell type-specific expression patterns. Our aim was to determine which receptors may be important in DAP12-associated bone pathologies. Here, we identify myeloid DAP12-associating lectin (MDL)-1 receptor (also known as CLEC5A) as a key regulator of synovial injury and bone erosion during autoimmune joint inflammation. Activation of MDL-1 leads to enhanced recruitment of inflammatory macrophages and neutrophils to the joint and promotes bone erosion. Functional blockade of MDL-1 receptor via Mdl1 deletion or treatment with MDL-1-Ig fusion protein reduces the clinical signs of autoimmune joint inflammation. These findings suggest that MDL-1 receptor may be a therapeutic target for treatment of immune-mediated skeletal disorders

Monitoring roof beam lateral displacement at the waste isolation pilot plant

Lateral displacement in the immediate roof beam at the Waste Isolation Pilot Plant (WIPP) is a significant factor in assessment of excavation performance for the design of ground control systems. Information on roof beam lateral displacement, expansion, fracture formation, as well as excavation convergence, is gathered using a variety of manually and remotely read instruments. Visual observations are also used when possible. This paper describes the methods used to measure lateral displacement, or offset, at the WIPP. Offset magnitudes are determined by the degree of occlusion in drillholes that intersect the offset plane. The Borehole Lateral Displacement Sensor (BLDS) was developed for installation at WIPP to monitor offset at a high degree of accuracy at a short reading frequency. Offset measurements have historically been obtained by visual estimation of borehole occlusion. Use of the BLDS will enable relationships between time dependent roof beam lateral displacement and expansion to be established in much shorter periods than is possible using visual observations. The instrument will also allow remote monitoring of roof beam displacement in areas where visual estimations are not possible. Continued monitoring of roof beam displacement, convergence, and expansion, is integral to timely and pertinent assessments of WIPP excavation performance

Transmission risk of COVID-19 in high school and college water polo

BACKGROUND: Concerns that athletes may be at a higher risk for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission has led to reduced participation in sports during the COVID-19 pandemic. We aimed to assess COVID-19 incidence and transmission during the spring 2021 high school and college water polo seasons across the United States. METHODS: This prospective observational study enrolled 1825 water polo athletes from 54 high schools and 36 colleges. Surveys were sent to coaches throughout the season, and survey data were collected and analyzed. RESULTS: We identified 17 COVID-19 cases among 1223 high school water polo athletes (1.4%) and 66 cases among 602 college athletes (11.0%). Of these cases, contact tracing suggested that three were water polo-associated in high school, and none were water polo-associated in college. Quarantine data suggest low transmission during water polo play as only three out of 232 (1.3%) high school athletes quarantined for a water polo-related exposure developed COVID-19. In college, none of the 54 athletes quarantined for exposure with an infected opponent contracted COVID-19. However, in both high school and college, despite the physical condition of water polo athletes, both high school (47%) and college athletes (21%) had prolonged return to play after contracting COVID-19, indicating the danger of COVID-19, even to athletes. CONCLUSIONS: While COVID-19 spread can occur during water polo play, few instances of spread occurred during the spring 2021 season, and transmission rates appear similar to those in other settings, such as school environments