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Combustions with fuel-spray atomizers are particularly susceptible to a low-frequency oscillation at idle and subidle conditions. For aeroengine combustors, the frequency of this oscillation is typically in the range 50-120 Hz and is commonly called "rumble". The mechanism involves interaction between the plenum around the burner and the combustion chamber. Pressure variations in the plenum or the combustor alter the inlet air and fuel spray characteristics, thereby changing the rate of combustion. This in turn leads to local "hot spots" which generate pressure oscillations as they convect through the downstream nozzle. In order to eliminate the combustion oscillations, it is essential to determine which fuel atomizers are particularly likely to lead to instability by quantifying their sensitivity to flow perturbations. This can be by identifying the system through understanding the transfer function, which represents the relationship between the unsteadiness of combustion and the inlet fuel and air. In the present work, various types of signals are applied to produce a small change in the inlet fuel and air flow rates, the response in the rate of heart release caused downstream as calculated and stored for subsequent analysis. Afterwards, the system transfer function is calculated by determining the coefficients of an IIR filter (Infinite Impulse Response) for which the output signal is the downstream heat release rate and the input signal is the inlet flow rate. The required transfer function the follows from the Fourier transform of this relationship. The resulting transfer functions are compared with those obtained by the forced harmonic oscillations at a fixed given frequency. Suitably, chosen input signals accurately recover the results for harmonic forcing at a single frequency range, but also give detailed information about the combustor response over a wide frequency range. There are two distinct forms to the low-frequency quasisteady response. In the... [ABSTRACT FROM AUTHOR]

Studies self-excited oscillation in combustors with fuel-sprays simulated using computational fluid dynamics. Discussion of mathematical models; Development of dynamic boundary conditions; Mechanism of instability.

Focuses on the characterization of metal organic vapor phase epitaxy-grown epitaxial oxygen-doped gallium arsenide for semi-insulating applications. Data on the concentrations of oxygen and aluminum determined from secondary-ion-mass-spectroscopy analysis of the samples; Sample preparation; Results.

Abstract: The objective of this study was to describe the pharmacokinetics (PK) of cytarabine (CA) after subcutaneous (SC) administration to dogs with meningoencephalomyelitis of unknown etiology (MUE). Twelve dogs received a single SC dose of CA at 50 mg/m2 as part of treatment of MUE. A sparse sampling technique was used to collect four blood samples from each dog from 0 to 360 min after administration. All dogs were concurrently receiving prednisone (0.5–2 mg kg−1day−1). Plasma CA concentrations were measured by HPLC, and pharmacokinetic parameters were estimated using nonlinear mixed‐effects modeling (NLME). Plasma drug concentrations ranged from 0.05 to 2.8 μg/ml. The population estimate (CV%) for elimination half‐life and Tmax of cytarabine in dogs was 1.09 (21.93) hr and 0.55 (51.03) hr, respectively. The volume of distribution per fraction absorbed was 976.31 (10.85%) ml/kg. Mean plasma concentration of CA for all dogs was above 1.0 μg/ml at the 30‐, 60‐, 90‐, and 120‐min time points. In this study, the pharmacokinetics of CA in dogs with MUE after a single 50 mg/m2 SC injection in dogs was similar to what has been previously reported in healthy beagles; there was moderate variability in the population estimates in this clinical population of dogs. [ABSTRACT FROM AUTHOR]

The use of online instruction is becoming more prevalent and transcends many disciplines. Nursing has been at the forefront of health professions utilizing distance education. Nearly half of all predoctoral dental programs report use of web-based or distance delivery. Comparatively, 22% of dental hygiene programs report use of this somewhat new approach to teaching. Distance learning provides a means for increasing access to and enrollment in dental hygiene programs. Individuals who cannot physically attend courses in dental hygiene benefit from the institutions that offer web-based classes. In today's environment, more individuals seek to advance their educational needs. Advanced dental hygiene degree programs may benefit by providing distance learning. Since 2000, the University of Missouri - Kansas City (UMKC), Division of Dental Hygiene has offered its degree completion program online. Its master's degree online program has been offered since 2001. Purpose. The purpose of this study is to describe the pre- and post-course graduate and degree completion students' perceptions of web-based courses offered at UMKC. Method. Over the course of 3 years, all students enrolled in required fall semester online classes were selected and agreed to participate in the study. Students were asked to fill out questionnaires prior to and at the completion of required online courses. There were no identifiers on the questionnaires. The surveys used in the study were derived from an instrument used by Wills and Stommel who examined graduate nursing students' perceptions of web-based courses. Results. Results indicate that students enjoy this method of learning. All students reported they would enroll in another online course if given the opportunity. Conclusion. Based on favorable student perceptions, UMKC will continue to provide this method of learning to students seeking advanced degrees in dental hygiene. [ABSTRACT FROM AUTHOR]

Summary The feasibility of using Dual-frequency IDentification SONar (DIDSON) for monitoring white sturgeon ( Acipenser transmontanus) presence and activity was tested near a known spawning area in the Columbia River, British Columbia, Canada. A fixed-station DIDSON system was deployed near the river bank adjacent to the spawning site in each 3 years (2007-2009). Fixed-station data were collected at this site in July and August each year, with an additional fixed-station site established in 2009 approximately 1.6 km upstream. A total of 267, 64, and 210 observations of sturgeon were documented based on fixed-station DIDSON sampling in 2007, 2008, and 2009, respectively. Sturgeon detections within the sample area (standardized by time and day) generally increased during late evening/early morning hours but did not appear to be related to flows. The DIDSON provided estimates of white sturgeon total lengths consistent with known length distributions for this population. Most sturgeon were detected at least 10 m away from the shoreline. These results demonstrate the feasibility of using fixed-station DIDSON for remotely monitoring white sturgeon in areas of known use. Observational data from this study also provided information on general sturgeon behaviour that is often difficult to assess with more conventional sampling methods. [ABSTRACT FROM AUTHOR]

Introduction: Therapeutic drug monitoring (TDM) has proven to be a valuable strategy for optimizing biologic therapies, among which are anti-tumor necrosis factor (anti-TNF) treatments in inflammatory bowel disease (IBD). In particular, reactive TDM has been shown to manage treatment failures more cost-effectively than empirical dose adjustments for anti-TNF drugs. However, several challenges currently impede the widespread adoption of TDM in clinical practice, particularly addressing the delay between sample collection and result availability. To overcome this limitation, the use of point-of-care technology tests (POCTs) is a potential solution. Point-of-care technology tests are medical diagnostic tests performed at the site of patient care to provide immediate results, allowing for quicker decision-making and treatment. The current standard of care (SOC) for drug level measurement relies on the enzyme-linked immunosorbent assay (ELISA), a method that is time-consuming and requires specialized personnel. This study aims to evaluate a novel, user-friendly, and efficient POCT method (ProciseDx Inc.) and compare its performance with the SOC ELISA in assessing infliximab and adalimumab levels in blood samples from IBD patients. Methods: In this prospective, single-center study, we collected blood samples from IBD patients, both CD and UC, receiving infliximab (87 IBD patients; 50% UC and 50% CD) or adalimumab (60 patients; 14% UC and 48% CD) and we analyzed the blood's drugs levels using both the ProciseDx Analyzer POC and the SOC ELISA. We examined the correlation between the two methods using statistical analyses, including the Deming regression test. Additionally, we assessed the ease of use, turnaround time, and overall practicality of the POCT in a clinical setting. Results: The ProciseDx test demonstrated a strong correlation with the SOC ELISA for measuring both infliximab and adalimumab levels. In particular, the overall correlation between the ProciseDx POCT and the ELISA assessments showed an r coefficient of 0.83 with an R squared value of 0.691 (95% CI 0.717-0.902) for IFX measurements, and an r coefficient of 0.85 with an R squared value of 0.739 (95% CI 0.720-0.930). Conclusions: the ProciseDx POC test offers significantly faster turnaround times and is more straightforward to use, making it a viable alternative for routine clinical monitoring. Despite its promising potential, further refinement and validation of the ProciseDx test are necessary to ensure its effectiveness across diverse patient populations and clinical settings. Future research should focus on optimizing the POC tests' performance and evaluating its long-term impact on IBD management.

Background/objectives: Although there is a need for evidence-based physical activity programs in rural communities, evaluating such programs is often challenging due to access-related barriers and measurement tools that are not designed for rural contexts. This study aimed to explore and better understand the day-to-day experiences of rural-dwelling children using wrist-worn PA trackers as part of a study to develop a health promotion program., Methods: Ten caregivers and child dyads were enrolled ( n = 20). The children wore accelerometers pre- and post-intervention. Semi-structured interviews were completed post-intervention and were audio recorded, transcribed, and summary reports were generated based on recurring themes., Results: The children had a mean age of 8.7 (SD = 1.4) years and the majority were male (80%). The caregivers were female, white, and had a mean age of 43.6 (SD = 8.5) years, with an annual income of ≥USD 40,000. Factors contributing to device wear times included low caregiver burden, device functioning as a watch, and device interactivity. The children reported that the devices were acceptable, but may have changed their physical activity behaviors, with children regularly checking their step count. The caregivers preferred devices that monitored the children's activity levels without sharing location data., Conclusions: Identifying acceptable and feasible strategies to measure physical activity is vital to developing effective health promotion efforts. The lessons learned may help develop evaluation plans for implementing rural physical activity programming.