3,422 research outputs found
Gibbs entropy and irreversible thermodynamics
Recently a number of approaches has been developed to connect the microscopic
dynamics of particle systems to the macroscopic properties of systems in
nonequilibrium stationary states, via the theory of dynamical systems. This way
a direct connection between dynamics and Irreversible Thermodynamics has been
claimed to have been found. However, the main quantity used in these studies is
a (coarse-grained) Gibbs entropy, which to us does not seem suitable, in its
present form, to characterize nonequilibrium states. Various simplified models
have also been devised to give explicit examples of how the coarse-grained
approach may succeed in giving a full description of the Irreversible
Thermodynamics. We analyze some of these models pointing out a number of
difficulties which, in our opinion, need to be overcome in order to establish a
physically relevant connection between these models and Irreversible
Thermodynamics.Comment: 19 pages, 4 eps figures, LaTeX2
Improvements on the Inhaler
Background: Inhalers are a commonplace in American health care and deliver crucial drugs to patients with COPD and asthma. Inhaler use has been shown to be unsatisfactory among patients resulting in ineffective medication delivery. The goal of this project was to improve the inhaler design for increased effectiveness and ease of use.
Methods: Our team first interviewed a Pulmonologist regarding patient inhaler use. Dr. Harry Kane demonstrated the proper use of an inhaler as well and described errors in inhaler use are due to patient technique. A variety of inhalers currently available were examined and were compared for ease of use.
Results: Interview with attending physician revealed numerous patient errors that impede effectiveness of inhaled medication. Two common mistakes were identified: patients inhaling too rapidly and patients dispensing the medication too late. Inhaling too rapidly decreases the fraction of drug that reaches the lungs, decreasing effectiveness. Dispensing the medication after a patient reaches total lung capacity (TLC) prevents the drug from reaching their lungs, decreasing effectiveness.
Conclusions: We conclude that inhalers could be used more effectively by addressing patient education and feedback mechanisms. Possible solutions discuss audible feedback to help coordinate patient breath with optimal dispersal timing. Future work includes prototyping a design and eliciting patient feedback
Visualising the number of people who cannot perform tasks related to product interactions
Understanding the number of people who cannot perform particular tasks helps to inform design decisions for mainstream products, such as the appropriate size and contrast of visual features. Making such informed decisions requires a dataset that is representative at the level of a national population, with sufficient scope and granularity to cover the types of actions associated with product use. Furthermore, visualisations are needed to bring the dataset to life, in order to better support comparing the number of people who cannot perform different tasks. The 1996/97 Disability Follow-up Survey remains the most recent Great British dataset to cover all types of ability losses that may be relevant to using everyday products. This paper presents new visualisations derived from this dataset, which are related to vision, hearing, cognition, mobility, dexterity and reach. Compared to previous publications on this dataset, the new visualisations contain task descriptions that have been simplified, described pictorially and separated out into different categories. Furthermore, two-dimensional visualisations are used to present exclusion results for products that require vision and/or hearing and for tasks that require each hand to do different things. In order to produce these new visualisations, the publicly available version of this dataset had to be reanalysed and recoded, which is described here-in detail.This is the author accepted manuscript. The final version is available from Springer via http://dx.doi.org/10.1007/s10209-013-0297-
Factors Influencing Physical and Technical Variability in the English Premier League
Purpose: To investigate match-to-match variability of physical and technical performances in English Premier League players and quantify the influence of positional and contextual factors. Methods: Match data (N = 451) were collected using a multicamera computerized tracking system across multiple seasons (2005ā06 to 2012ā13). The coefficient of variation (CV) was calculated from match to match for physical and technical performances in selected positions across different match contexts (location, standard, and result). Results: Wide midfielders demonstrated the greatest CVs for total distance (4.9% Ā± 5.9%) and central midfielders the smallest (3.6% ļæ½} 2.0%); nevertheless, all positions exhibited CVs .05, effect size [ES] 0.1ā0.3). Central defenders demonstrated the greatest CVs and wide midfielders the lowest for both high-intensity running (20.2% Ā± 8.8% and 13.7% Ā± 7.7%, P < .05, ES 0.4ā0.8) and sprint distance (32.3% Ā± 13.8% and 22.6% Ā± 11.2%, P < .05, ES 0.5ā0.8). Technical indicators such as tackles (83.7% Ā± 42.3%), possessions won (47.2% Ā± 27.9%), and interceptions (59.1% Ā± 37.3%) illustrated substantial variability for attackers compared with all other positions (P < .05, ES 0.4ā1.1). Central defenders demonstrated large variability for the number of times tackled per match (144.9% Ā± 58.3%) and passes attempted and received compared with other positions (39.2% Ā± 17.5% and 46.9% Ā± 20.2%, P < .001, ES 0.6ā1.8). Contextual factors had limited impact on the variability of physical and technical parameters. Conclusions: The data demonstrate that technical parameters varied more from match to match than physical parameters. Defensive players (fullbacks and central defenders) displayed higher CVs for offensive technical variables, while attacking players (attackers and wide midfielders) exhibited higher CVs for defensive technical variables. Physical and technical performances are variable per se regardless of context
Increasing Tumor Volume Is Predictive of Poor Overall and Progression-Free Survival: Secondary Analysis of the Radiation Therapy Oncology Group 93-11 Phase I-II Radiation Dose-Escalation Study In Patients With Inoperable Non-Small-Cell Lung Cancer
Purpose
Patients with nonāsmall-cell lung cancer (NSCLC) in the Radiation Therapy Oncology Group (RTOG) 93-11 trial received radiation doses of 70.9, 77.4, 83.8, or 90.3 Gy. The locoregional control and survival rates were similar among the various dose levels.We investigated the effect of the gross tumor volume (GTV) on the outcome.
Methods and Materials
The GTV was defined as the sum of the volumes of the primary tumor and involved lymph nodes. The tumor response, median survival time (MST), and progression-free survival (PFS) were analyzed separately for smaller (ā¤45 cm3) vs. larger (\u3e45 cm3) tumors.
Results
The distribution of the GTV was as follows: ā¤45 cm3 in 79 (49%) and \u3e45 cm3 in 82 (51%) of 161 patients. The median GTV was 47.3 cm3. N0 status and female gender were associated with better tumor responses. Patients with smaller (ā¤45 cm3) tumors achieved a longer MST and better PFS than did patients with larger (\u3e45 cm3) tumors (29.7 vs. 13.3 months, p \u3c 0.0001; and 15.8 vs. 8.3 months, p \u3c 0.0001, respectively). Increasing the radiation dose had no effect on the MST or PFS. On multivariate analysis, only a smaller GTV was a significant prognostic factor for improved MST and PFS (hazard ratio [HR], 2.12, p = 0.0002; and HR, 2.0, p = 0.0002, respectively). The GTV as a continuous variable was also significantly associated with the MST and PFS (HR, 1.59, p \u3c 0.0001; and HR, 1.39, p \u3c 0.0001, respectively).
Conclusions
Radiation dose escalation up to 90.3 Gy did not result in improved MST or PFS. The tumor responses were greater in node-negative patients and women. An increasing GTV was strongly associated with decreased MST and PFS. Future radiotherapy trials patients might need to use stratification by tumor volume.
Int. J. Radiation Oncology Biol. Physics, Volume 70, No. 2, pp. 385-390, 200
Scholarly Concentrations Program: A PRIME Approach to Addressing Care for the Medically Underserved and Vulnerable Populations
Examine how well the structure of the Scholarly Concentrations Program and content of each concentration relates to the goals of the federal Health Resources and Services Administration grant received to create more interest and prepare more medical school graduates to care for medically underserved and vulnerable populations. The grant funds the Primary Care Reaffirmation for Indiana Medical Education, or PRIME. project.Ā A review of how concentrations align with the grant was conducted by reviewing program, concentration and course learning objectives and mapping to the grant objectives. Numerous concentrations were found to be an excellent fit, creating a PRIME opportunity to enhance the SC Program and move the needle on the grant objectives
Principles of Management of Severe Hyponatremia
Hyponatremia represents a serious health hazard.1 Hospitalized patients,2 nursing home residents,3 women,4,5 and children6 exhibit high frequency and/or severity of hyponatremia. Hyponatremia developing during the course of other morbid conditions increases their severity.7ā10 Estimates of direct costs for treating hyponatremia in the United States ranged between 3.6 billion.11
Clinical manifestations of hyponatremia are universal12,13 and range from subtle (disturbances of balance, problems in cognition detected only during speciļ¬c testing) to life-threatening manifestations of increased intracranial pressure with life-threatening hypoxia14ā16 and noncardiac pulmonary edema.17 Although the treating physicians must make an accurate diagnosis based on well-established and described clinical criteria,1 treatment is also guided by the severity of these manifestations. The magnitude and rate of increase in serum sodium concentration ([Na]) during treatment are critical. Overcorrection of chronic hyponatremia may lead to osmotic myelinolysis,18ā21 whereas undercorrection may fail to prevent life-threatening manifestations.1,2
Improving the Inhaler
Background: Inhalers used to dispense various pharmacological agents play an important role in the care of patients with pulmonary disease. These pharmacological agents can be very effective, however, many patients that use inhalers often deliver these drugs incorrectly or in a sub-optimal manner. Our project aims to improve the design of the inhaler in order to increase the effectiveness of drug delivery and also ease of patient use.
Methods: We interviewed a critical care pulmonologist regarding patient inhaler use and compliance. This physician offered information about proper inhaler use and described common errors that patients encounter when attempting to dispense drugs via inhalers. Both steroidal and albuterol inhalers that are currently being prescribed were allocated for our examination and use to help develop a more user friendly model.
Results: The pulmonologist illustrated several errors that patients will commonly make which can degrade the efficacy of the inhaled drug delivery. One frequently encountered error was that drug is dispensed by the patient once they had already reached their total lung capacity, or inhaled fully. This sort of error leads to the drug being dispensed into the throat and failure to reach the intended target, the lungs. Additionally, the physician noted that patients often forget to administer their inhaled drugs because the inhaler does not fit comfortably into the patientās pocket and so it is not optimally portable.
Conclusion: Our research suggests that inhaler design could be improved in order to increase the effectiveness of drug delivery and patient compliance. We are considering incorporating audible actuation clues that will alert the patient when to dispense the drug, and also provide electronic feedback to the patientās mobile device. This would help educate the patient on how to coordinate their breathing with actuation of the device to dispense the medication
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