445 research outputs found
Reducing Printed Circuit Board Emissions with Low-Noise Design Practices
This paper presents the results of an experiment designed to determine the effectiveness of adopting several low-noise printed circuit board (PCB) design practices. Two boards were designed and fabricated, each consisting of identical mixed signal circuitry. Several important differences were introduced between the board layouts: one board was constructed using recommended low-noise practices and the other constructed without such attention. The emissions from the two boards were then measured and compared, demonstrating an improvement in radiated emissions of up to 22 dB
Life-Threatening Adenovirus Infections in the Setting of the Immunocompromised Allogeneic Stem Cell Transplant Patients
A single institution case series of adenovirus infections after allogeneic hematopoietic stem cell transplantation is presented to highlight the consideration for adenovirus infections as an etiology in patients with rapid hepatic or other sudden organ deterioration in the setting of apparent GVHD stabilization. The series also highlights that survival is limited with these infections often due in part to concomitant opportunistic infections. In addition, the pathophysiological events, such as GVHD and hepatic dysfunction, may complicate the clinical picture and delay therapy of an opportunistic infection. This is particularly true for adenoviral infections as they also have a distinct clinical picture in immunocompromised patients when compared to immune competent patients. Adenovirus infections also have the additional challenge that its treatment, cidofovir, has associated toxicities that can delay its administration. Recent developments has yielded an assay that can be used in the early detection and for serial determinations of adenovirus in patients with advanced GVHD, as well as a new therapeutic agent currently undergoing clinical trials
The effects of water temperature on the juvenile performance of two tropical damselfishes expatriating to temperate reefs
Ocean warming associated with global climate change is already inducing geographic range shifts of marine species. Juvenile coral reef fishes transported into temperate latitudes (termed 'vagrant' fishes) can experience winter water temperatures below their normal thermal minimum. Such environmental extremes may increase energetic costs for such fishes, resulting in reduced performance, which may be the governing factor that limits the potential for poleward range expansion of such fishes. This study compared the juvenile physiological performance and behaviour of two congeneric tropical damselfishes which settle during austral summer months within temperate eastern Australia: Abudefduf vaigiensis have an extended southern range, and lower threshold survival temperature than the congeneric A. whitleyi. Physiological and behavioural performance parameters that may be affected by cooler temperature regimes at higher latitudes were measured in aquaria. Lower water temperature resulted in reduced growth rates, feeding rates, burst escape speed and metabolic rates of both species, with significantly reduced performance (up to six-fold reductions) for fishes reared at 18°C relative to 22°C and 26°C. However, A. whitleyi exhibited lower growth rates than A. vaigiensis across all temperatures, and lower aerobic capacity at the lowest temperature (18°C). This difference between species in growth and metabolic capacity suggests that the extended southern distribution and greater overwintering success of A. vaigiensis, in comparison to A. whitleyi is related to thermal performance parameters which are critical in maintaining individual health and survival. Our results support previous findings in the region that water temperature below 22°C represents a critical physiological threshold for tropical Abudefduf species expatriating into temperate south-eastern Australia
Compounding heatwave-extreme rainfall events driven by fronts, high moisture, and atmospheric instability
Heatwaves have been shown to increase the likelihood and intensity of extreme rainfall occurring immediately afterward, potentially leading to increased flood risk. However, the exact mechanisms connecting heatwaves to extreme rainfall remain poorly understood. In this study, we use weather type data sets for Australia and Europe to identify weather patterns, including fronts, cyclones, and thunderstorm conditions, associated with heatwave terminations and following extreme rainfall events. We further analyze, using reanalysis data, how atmospheric instability and moisture availability change before and after the heatwave termination depending on whether the heatwave is followed by extreme rainfall, as well as the location of the heatwave. We find that most heatwaves terminate during thunderstorm and/or frontal conditions. Additionally, atmospheric instability and moisture availability increase several days before the heatwave termination; but only if heatwaves are followed by extreme rainfall. We also find that atmospheric instability and moisture after a heatwave are significantly higher than expected from climatology for the same time of the year, and that highest values of instability and moisture are associated with highest post-heatwave rainfall intensities. We conclude that the joint presence of high atmospheric instability, moisture, as well as frontal systems are likely to explain why rainfall is generally more extreme and likely after heatwaves, as well as why this compound hazard is mainly found in the non-arid mid and high latitudes. An improved understanding of the drivers of these compound events will help assess potential changing impacts in the future
A 3-D PYRAMID/PRISM APPROACH TO VIEW KNOWLEDGE REQUIREMENTS FOR THE BATCH MEANS METHOD WHEN TAUGHT IN A LANGUAGE-FOCUSED, UNDERGRADUATE SIMULATION COURSE
We develop a 3-D knowledge pyramid/prism model to structure the relationships of (i) lower-level learning, (ii) âoptional â knowledge bases, (iii) concurrent knowledge, and (ii) new knowledge; so one may view the learning needs of a higher-level learning objective. Our paradigm stems from Bloomâs taxonomy of learning, but has the advantage of supporting âjust-in-time â and âlearn-by-doingâ delivery, teaching and learning styles. We illustrate the paradigm through the BMMKP (the 3-D knowledge pyramid/prism model of the highest-level, batch-means-method learning objective for our language-focused, undergraduate course). The BMMKP reveals how highly dependent and fully integrated this learning is to calculus, probability, statistics, and queuing theoryâregardless of the simulation modeling language chosen to teach in the course. The BMMKP is then used to develop a set of lower-level learning objectives for the undergraduate course. The 3-D pyramid/prism approach should lend itself well as a communication tool for visualizing other simulation learning objectives.
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Urinary Retention Evaluation and Catheterization Algorithm for Adult Inpatients
Importance: Acute urinary retention (UR) is common, yet variations in diagnosis and management can lead to inappropriate catheterization and harm. Objective: To develop an algorithm for screening and management of UR among adult inpatients. Design, Setting, and Participants: In this mixed-methods study using the RAND/UCLA Appropriateness Method and qualitative interviews, an 11-member multidisciplinary expert panel of nurses and physicians from across the US used a formal multi-round process from March to May 2015 to rate 107 clinical scenarios involving diagnosis and management of adult UR in postoperative and medical inpatients. The panel ratings informed the first algorithm draft. Semistructured interviews were conducted from October 2020 to May 2021 with 33 frontline cliniciansânurses and surgeons from 5 Michigan hospitalsâto gather feedback and inform algorithm refinements. Main Outcomes and Measures: Panelists categorized scenarios assessing when to use bladder scanners, catheterization at various scanned bladder volumes, and choice of catheterization modalities as appropriate, inappropriate, or uncertain. Next, qualitative methods were used to understand the perceived need, usability, and potential algorithm uses. Results: The 11-member expert panel (10 men and 1 woman) used the RAND/UCLA Appropriateness Method to develop a UR algorithm including the following: (1) bladder scanners were preferred over catheterization for UR diagnosis in symptomatic patients or starting as soon as 3 hours since last void if asymptomatic, (2) bladder scanner volumes appropriate to prompt catheterization were 300 mL or greater in symptomatic patients and 500 mL or greater in asymptomatic patients, and (3) intermittent was preferred to indwelling catheterization for managing lower bladder volumes. Interview findings were organized into 3 domains (perceived need, feedback on algorithm, and implementation suggestions). The 33 frontline clinicians (9 men and 24 women) who reviewed the algorithm reported that an evidence-based protocol (1) was needed and could be helpful to clinicians, (2) should be simple and graphically appealing to improve rapid clinician review, and (3) should be integrated within the electronic medical record and prominently displayed in hospital units to increase awareness. The draft algorithm was iteratively refined based on stakeholder feedback. Conclusions and Relevance: In this study using a systematic, multidisciplinary, evidence- and expert opinionâbased approach, a UR evaluation and catheterization algorithm was developed to improve patient safety by increasing appropriate use of bladder scanners and catheterization. This algorithm addresses the need for practical guidance to manage UR among adult inpatients.</p
Assessing Cyberbiosecurity Vulnerabilities and Infrastructure Resilience
The convergence of advances in biotechnology with laboratory automation, access to data, and computational biology has democratized biotechnology and accelerated the development of new therapeutics. However, increased access to biotechnology in the digital age has also introduced additional security concerns and ultimately, spawned the new discipline of cyberbiosecurity, which encompasses cybersecurity, cyber-physical security, and biosecurity considerations. With the emergence of this new discipline comes the need for a logical, repeatable, and shared approach for evaluating facility and system vulnerabilities to cyberbiosecurity threats. In this paper, we outline the foundation of an assessment framework for cyberbiosecurity, accounting for both security and resilience factors in the physical and cyber domains. This is a unique problem set, but despite the complexity of the cyberbiosecurity field in terms of operations and governance, previous experience developing and implementing physical and cyber assessments applicable to a wide spectrum of critical infrastructure sectors provides a validated point of departure for a cyberbiosecurity assessment framework. This approach proposes to integrate existing capabilities and proven methodologies from the infrastructure assessment realm (e.g., decision science, physical security, infrastructure resilience, cybersecurity) with new expertise and requirements in the cyberbiosecurity space (e.g., biotechnology, biomanufacturing, genomics) in order to forge a flexible and defensible approach to identifying and mitigating vulnerabilities. Determining where vulnerabilities reside within cyberbiosecurity business processes can help public and private sector partners create an assessment framework to identify mitigation options for consideration that are both economically and practically viable and ultimately, allow them to manage risk more effectively
Hepatic Mitochondrial Dysfunction and Risk of Liver Disease in an Ovine Model of âPCOS Malesâ
First-degree male relatives of polycystic ovary syndrome (PCOS) sufferers can develop metabolic abnormalities evidenced by elevated circulating cholesterol and triglycerides, suggestive of a male PCOS equivalent. Similarly, male sheep overexposed to excess androgens in fetal life develop dyslipidaemia in adolescence. Dyslipidaemia, altered lipid metabolism, and dysfunctional hepatic mitochondria are associated with the development of non-alcoholic liver disease (NAFLD). We therefore dissected hepatic mitochondrial function and lipid metabolism in adolescent prenatally androgenized (PA) males from an ovine model of PCOS. Testosterone was directly administered to male ovine fetuses to create prenatal androgenic overexposure. Liver RNA sequencing and proteomics occurred at 6 months of age. Hepatic lipids, glycogen, ATP, reactive oxygen species (ROS), DNA damage, and collagen were assessed. Adolescent PA males had an increased accumulation of hepatic cholesterol and glycogen, together with perturbed glucose and fatty acid metabolism, mitochondrial dysfunction, with altered mitochondrial transport, decreased oxidative phosphorylation and ATP synthesis, and impaired mitophagy. Mitochondrial dysfunction in PA males was associated with increased hepatic ROS level and signs of early liver fibrosis, with clinical relevance to NAFLD progression. We conclude that excess in utero androgen exposure in male fetuses leads to a PCOS-like metabolic phenotype with dysregulated mitochondrial function and likely lifelong health sequelae
Associations of sedentary behaviour, physical activity, blood pressure and anthropometric measures with cardiorespiratory fitness in children with cerebral palsy
Background - Children with cerebral palsy (CP) have poor cardiorespiratory fitness in comparison to their peers with typical development, which may be due to low levels of physical activity. Poor cardiorespiratory fitness may contribute to increased cardiometabolic risk. Purpose - The aim of this study was to determine the association between sedentary behaviour, physical activity and cardiorespiratory fitness in children with CP. An objective was to determine the association between cardiorespiratory fitness, anthropometric measures and blood pressure in children with CP. Methods- This study included 55 ambulatory children with CP [mean (SD) age 11.3 (0.2) yr, range 6-17 yr; Gross Motor Function Classification System (GMFCS) levels I and II]. Anthropometric measures (BMI, waist circumference and waist-height ratio) and blood pressure were taken. Cardiorespiratory fitness was measured using a 10 m shuttle run test. Children were classified as low, middle and high fitness according to level achieved on the test using reference curves. Physical activity was measured by accelerometry over 7 days. In addition to total activity, time in sedentary behaviour and light, moderate, vigorous, and sustained moderate-to-vigorous activity (â„10 min bouts) were calculated. Results - Multiple regression analyses revealed that vigorous activity (ÎČ = 0.339, p<0.01), sustained moderate-to-vigorous activity (ÎČ = 0.250, p<0.05) and total activity (ÎČ = 0.238, p<0.05) were associated with level achieved on the shuttle run test after adjustment for age, sex and GMFCS level. Children with high fitness spent more time in vigorous activity than children with middle fitness (p<0.05). Shuttle run test level was negatively associated with BMI (r2 = -0.451, p<0.01), waist circumference (r2 = -0.560, p<0.001), waist-height ratio (r2 = -0.560, p<0.001) and systolic blood pressure (r2 = -0.306, p<0.05) after adjustment for age, sex and GMFCS level. Conclusions - Participation in physical activity, particularly at a vigorous intensity, is associated with high cardiorespiratory fitness in children with CP. Low cardiorespiratory fitness is associated with increased cardiometabolic risk
Noninvasive evaluation of hand circulation before radial artery harvest for coronary artery bypass grafting
AbstractObjective: Radial artery harvesting for coronary artery bypass may lead to digit ischemia if collateral hand circulation is inadequate. The modified Allen's test is the most common preoperative screening test used. Unfortunately, this test has high false-positive and false-negative rates. The purpose of this study was to compare the results of a modified Allen's test with digit pressure change during radial artery compression for assessing collateral circulation before radial artery harvest. Methods: One hundred twenty-nine consecutive patients were studied before coronary artery bypass operations. A modified Allen's test was performed with Doppler ultrasound to assess blood flow in the superficial palmar arch before and during radial artery compression. A decreased audible Doppler signal after radial artery compression was considered a positive modified Allen's test. First and second digit pressures were measured before and during radial artery compression. A decrease in digit pressure of 40 mm Hg or more (digit ÎP) with radial artery compression was considered positive. Results: Seven of 14 dominant extremities (50%) and 8 of the 16 nondominant extremities (50%) with a positive modified Allen's test had a digit ÎP of less than 40 mm Hg (false positive). Sixteen of 115 dominant extremities (14%) and 5 of 112 nondominant extremities (4%) with a negative Allen's test had a digit ÎP of 40 mm Hg or more with radial artery compression (false negative). Conclusion: Use of the modified Allen's test for screening before radial artery harvest may unnecessarily exclude some patients from use of this conduit and may also place a number of patients at risk for digit ischemia from such harvest. Direct digit pressure measurement is a simple, objective method that may more precisely select patients for radial artery harvest. Additional studies are needed to define objective digital pressure criteria that will accurately predict patients at risk for hand ischemia after radial harvest. (J Thorac Cardiovasc Surg 1999;117:261-6
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