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Physical Review. E Sep 2019Viscoelastically coupled excitable oscillators are used to model individually beating spatially separated cardiomyocytes surrounded by an extracellular matrix (ECM). We...
Viscoelastically coupled excitable oscillators are used to model individually beating spatially separated cardiomyocytes surrounded by an extracellular matrix (ECM). We investigate how mechanical coupling via the ECM can synchronize two such oscillators with excitation contraction coupling and electromechanical feedback and how this synchronization depends on the rheological properties of the ECM. Extending our study to a linear chain of coupled oscillators we find a transition to synchronization as the ECM becomes stiffer. In the case of purely elastic coupling we observe antiphase chimera states.
PubMed: 31640069
DOI: 10.1103/PhysRevE.100.032214 -
International Journal of Clinical... Oct 2018Background A clinical decision support system (CDSS) linked to the computerized physician order entry may help improve prescription appropriateness in inpatients with...
Background A clinical decision support system (CDSS) linked to the computerized physician order entry may help improve prescription appropriateness in inpatients with renal insufficiency. Objective To evaluate the impact on prescription appropriateness of a CDSS prescriber alert for 85 drugs in renal failure patients. Setting Before-after study in a 975-bed academic hospital. Method Prescriptions of patients with renal failure were reviewed during two comparable periods of 6 days each, before and after the implementation of the CDSS (September 2009 and 2010). Main outcome measure The proportion of inappropriate dosages of 85 drugs included in the CDSS was compared in the pre- and post-implementation group. Results Six hundred and fifteen patients were included in the study (301 in pre- and 314 in post-implementation periods). In the pre- and post-implementation period, respectively 2882 and 3485 prescriptions were evaluated, of which 14.9 and 16.6% triggered an alert. Among these, the dosage was inappropriate in respectively 25.4 and 24.6% of prescriptions in the pre- and post-implementation periods (OR 0.97; 95% CI 0.72-1.29). The most frequently involved drugs were paracetamol, perindopril, tramadol and allopurinol. Conclusion The implementation of a CDSS did not significantly reduce the proportion of inappropriate drug dosages in patients with renal failure. Further research is required to investigate the reasons why prescribers override alerts. Collaboration with clinical pharmacists might improve compliance with the CDSS recommendations.
Topics: Aged; Aged, 80 and over; Decision Support Systems, Clinical; Dose-Response Relationship, Drug; Drug Therapy, Computer-Assisted; Female; Humans; Inappropriate Prescribing; Male; Medical Order Entry Systems; Middle Aged; Pharmaceutical Preparations; Practice Patterns, Physicians'; Renal Insufficiency
PubMed: 29785684
DOI: 10.1007/s11096-018-0612-1 -
Medwave Sep 2017Our institution implemented the use of pre-designed labeling of intravenous drugs and fluids, administration routes and infusion pumps of to prevent medication errors.
INTRODUCTION
Our institution implemented the use of pre-designed labeling of intravenous drugs and fluids, administration routes and infusion pumps of to prevent medication errors.
OBJECTIVE
To evaluate the effectiveness of predesigned labeling in reducing medication errors in the preparation and administration stages of prescribed medication in patients hospitalized with invasive lines, and to characterize medication errors.
METHODS
This is a pre/post intervention study. Pre-intervention group: invasively administered dose from July 1st to December 31st, 2014, using traditional labeling (adhesive paper handwritten note). Post-intervention group: dose administered from January 1st to June 30th, 2015, using predesigned labeling (labeling with preset data-adhesive labels, color- grouped by drugs, labels with colors for invasive lines). Outcome: medication errors in hospitalized patients, as measured with notification form and record electronics. Tabulation/analysis Stata-10, with descriptive statistics, hypotheses testing, estimating risk with 95% confidence.
RESULTS
In the pre-intervention group, 5,819 doses of drugs were administered invasively in 634 patients. Error rate of 1.4 x 1,000 administrations. The post-intervention group of 1088 doses comprised 8,585 patients with similar routes of administration. The error rate was 0.3 x 1,000 (p = 0.034). Patients receiving medication through an invasive route who did not use predesigned labeling had 4.6 times more risk of medication error than those who had used predesigned labels (95% CI: 1.25 to 25.4). The adult critically ill patient unit had the highest proportion of medication errors. The most frequent error was wrong dose administration. 41.2% produced harm to the patient.
CONCLUSIONS
The use of predesigned labeling in invasive lines reduces errors in medication in the last two phases: preparation and administration.
Topics: Administration, Intravenous; Drug Labeling; Hospitalization; Humans; Infusion Pumps; Medication Errors; Medication Systems, Hospital; Pharmaceutical Preparations
PubMed: 28885996
DOI: 10.5867/medwave.2017.08.7038 -
Physical Review. E Dec 2022A two-dimensional Monte Carlo simulation of dead-end diafiltration of bidispersed particle suspensions was performed. The diafiltration process involves separation of...
A two-dimensional Monte Carlo simulation of dead-end diafiltration of bidispersed particle suspensions was performed. The diafiltration process involves separation of components based on their size by using a permeable membrane. The continuous model was applied to study separation of mixture of disks with diameter d and D (D>d). It was assumed that the membrane at the bottom was permeable to the particles of the smaller diameter d, and impermeable to the particles of the larger diameter D. The process of vertical filtration was accompanied by the simultaneous Brownian motion of the particles and downward movement of the piston. The mixtures with different numerical concentrations of particles, diameter ratio, and initial size of the systems in the vertical direction L_{y} have been studied. The time dependencies of the rejection coefficient k and relative height of suspension h/L_{y} revealed the presence of complete and incomplete separation regimes. The presence of filtration and diffusion-driven stratification of the disks in the vertical direction was observed. The phenomenon of incomplete separation was explained by the formation of an impenetrable barrier from larger particles at the bottom of the deposit.
Topics: Monte Carlo Method; Suspensions; Computer Simulation; Particle Size
PubMed: 36671101
DOI: 10.1103/PhysRevE.106.064610 -
Journal of Voice : Official Journal of... Mar 2015To evaluate short- and long-term vocal outcomes after medialization laryngoplasty (ML) using a silastic implant in patients with unilateral vocal fold paralysis (UVFP).
OBJECTIVE
To evaluate short- and long-term vocal outcomes after medialization laryngoplasty (ML) using a silastic implant in patients with unilateral vocal fold paralysis (UVFP).
DESIGN AND METHODS
Prospective study of consecutive patients undergoing ML with silastic (MLS) diagnosed with UVFP from 2009 till 2012 and with at least 9 months follow-up. Pre- and post-treatment maximum phonation time (MPT) and voice handicap index (VHI) scores were compared to assess the impact of ML on these outcomes. Patients with high vagal lesions or lateralized vocal folds (very low MPT) were compared with the entire group and the literature.
RESULTS
A total of 124 patients with UVFP underwent MLS. Forty-six patients were excluded as they either had a Gore-Tex implant (eight), short follow-up (20), or the primary case was a revision (18). Seventy-eight patients were included. Pretreatment mean VHI (total score) was 67 for the entire cohort. Postoperative VHI score was significantly lower both in short-term (3-8 weeks) follow-up, mean score 27 (paired t-test, P < 0.05) and in long-term follow-up (9-12 months), mean score 22 (P < 0.05). MPT was significantly improved from 8.3 pretreatment to 22.6 at short-term follow-up (P < 0.05) and to 24.2 long-term follow-up (P < 0.05). There were no significant differences between entire cohort and patients with a lateralized vocal fold or high vagal lesion. Comparable results were present when compared with the literature using similar metrics in patients undergoing an arytenoid procedure with/without medialization.
CONCLUSION
MLS alone is effective in managing UVFP in most patients.
Topics: Adult; Aged; Aged, 80 and over; Arytenoid Cartilage; Female; Follow-Up Studies; Humans; Laryngoplasty; Male; Medicalization; Middle Aged; Prospective Studies; Time Factors; Vocal Cord Paralysis; Vocal Cords; Voice Quality
PubMed: 25510165
DOI: 10.1016/j.jvoice.2014.07.008 -
Physical Review. E Jun 2023The Delta-Notch system plays a vital role in many areas of biology and typically forms a salt and pepper pattern in which cells strongly expressing Delta and cells...
The Delta-Notch system plays a vital role in many areas of biology and typically forms a salt and pepper pattern in which cells strongly expressing Delta and cells strongly expressing Notch are alternately aligned via lateral inhibition. In this study, we consider cell rearrangement events, such as cell mixing and proliferation, that alter the spatial structure itself and affect the pattern dynamics. We model cell rearrangement events by a Poisson process and analyze the model while preserving the discrete properties of the spatial structure. We investigate the effects of the intermittent perturbations arising from these cell rearrangement events on the discrete spatial structure itself in the context of pattern formation and by using an analytical approach, coupled with numerical simulation. We find that the homogeneous expression pattern is stabilized if the frequency of cell rearrangement events is sufficiently large. We analytically obtain the balanced frequencies of the cell rearrangement events where the decrease of the pattern amplitude, as a result of cell rearrangement, is balanced by the increase in amplitude due to the Delta-Notch interaction dynamics. Our framework, while applied here to the specific case of the Delta-Notch system, is applicable more widely to other pattern formation mechanisms.
Topics: Signal Transduction; Receptors, Notch; Membrane Proteins; Cell Communication; Cell Differentiation
PubMed: 37464594
DOI: 10.1103/PhysRevE.107.064404 -
Physical Review. E May 2023Colloidal spheres in weakly conductive fluids roll back and forth across the surface of a plane electrode when subject to strong electric fields. The so-called Quincke...
Colloidal spheres in weakly conductive fluids roll back and forth across the surface of a plane electrode when subject to strong electric fields. The so-called Quincke oscillators provide a basis for active matter based on self-oscillating units that can move, align, and synchronize within dynamic particle assemblies. Here, we develop a dynamical model for oscillations of a spherical particle and investigate the coupled dynamics of two such oscillators in the plane normal to the field. Building on existing descriptions of Quincke rotation, the model describes the dynamics of the charge, dipole, and quadrupole moments due to charge accumulation at the particle-fluid interface and particle rotation in the external field. The dynamics of the charge moments are coupled by the addition of a conductivity gradient, which describes asymmetries in the rates of charging near the electrode. We study the behavior of this model as a function of the field strength and gradient magnitude to identify the conditions required for sustained oscillations. We investigate the dynamics of two neighboring oscillators coupled by far field electric and hydrodynamic interactions in an unbounded fluid. Particles prefer to align and synchronize their rotary oscillations along the line of centers. The numerical results are reproduced and explained by accurate low-order approximations of the system dynamics based on weakly coupled oscillator theory. The coarse-grained dynamics of the oscillator phase and angle can be used to investigate collective behaviors within ensembles of many self-oscillating colloids.
Topics: Rotation; Hydrodynamics; Colloids
PubMed: 37328991
DOI: 10.1103/PhysRevE.107.054603 -
Expert Review of Clinical Pharmacology Jan 2019Nutraceuticals, up today, do not have a specific definition distinct from those of other food-derived categories, e.g. food supplements, herbal products, pre and...
Nutraceuticals, up today, do not have a specific definition distinct from those of other food-derived categories, e.g. food supplements, herbal products, pre and probiotics, functional foods, etc. They have, however, a pharmacological beneficial effect on health. Many studies have been recently addressed to assess their safety, efficacy, and regulation since they are getting growing attention by market and research, with the aim to clear the difference between them and other market available food-derived products that claim beneficial effect on health. Areas covered: The understanding of the potential mechanisms of action of pharmaceutically active substances contained in nutraceuticals that may improve health and reduce the risk of pathological conditions while enhancing overall well-being is the challenge for nutraceuticals to be considered as a preventive and therapeutic efficient tool in facing some diseases. Expert commentary: It is of utmost importance to have a proper and unequivocal definition of nutraceuticals and a shared regulation. Nevertheless, there is a lack of clear information and, often, the claimed health benefits may not be properly substantiated by safety and by efficacy in vivo data, which can induce false expectations and miss the target for a product to be effective, as claimed.
Topics: Dietary Supplements; Humans; Legislation, Drug; Legislation, Food; Pharmaceutical Preparations; Terminology as Topic
PubMed: 30484336
DOI: 10.1080/17512433.2019.1552135 -
International Journal of Medical... May 2020'Look-alike, sound-alike' (LASA) medicines may be confused by prescribers, pharmacists, nurses and patients, with serious consequences for patient safety. The current...
BACKGROUND
'Look-alike, sound-alike' (LASA) medicines may be confused by prescribers, pharmacists, nurses and patients, with serious consequences for patient safety. The current research aimed to develop and trial software to proactively identify LASA medicines by computing medicine name similarity scores.
METHODS
Literature review identified open-source software from the United States Food and Drug Administration for screening of proposed medicine names. We adapted and refined this software to compute similarity scores (0.0000-1.0000) for all possible pairs of medicines registered in Australia. Two-fold exploratory analysis compared: RESULTS: Screening of the Australian medicines register identified 7,750 medicine pairs with at least moderate (arbitrarily ≥0.6600) name similarity, including many oncology, immunomodulating and neuromuscular-blocking medicines. Computed similarity scores and resulting risk categories demonstrated a modest correlation with the manually-calculated similarity scores (r = 0.324, p < 0.002, 95 % CI 0.119-0.529). However, agreement between the resulting risk categories was not significant (Cohen's kappa = -0.162, standard error = 0.063).
CONCLUSIONS
The software (LASA v2) has potential to identify pairs of confusable medicines. It is recommended to supplement incident reports in risk-management programs, and to facilitate pre-screening of medicine names prior to brand/trade name approval and inclusion of medicines in formularies.
Topics: Algorithms; Australia; Drug Labeling; Humans; Medication Errors; Patient Safety; Pharmaceutical Preparations; Pharmacists; Software
PubMed: 32172184
DOI: 10.1016/j.ijmedinf.2020.104119 -
Physical Review. E Dec 2022Despite substantial progress in nonequilibrium physics, steady-state (s.s.) probabilities remain intractable to analysis. For a Markov process, s.s. probabilities can be...
Despite substantial progress in nonequilibrium physics, steady-state (s.s.) probabilities remain intractable to analysis. For a Markov process, s.s. probabilities can be expressed in terms of transition rates using the graph-theoretic matrix-tree theorem (MTT). The MTT reveals that, away from equilibrium, s.s. probabilities become globally dependent on all rates, with expressions growing exponentially in the system size. This overwhelming complexity and lack of thermodynamic interpretation have greatly impeded analysis. Here we show that s.s. probabilities are proportional to the average of exp(-S(P)), where S(P) is the entropy generated along minimal paths P in the graph, and the average is taken over a probability distribution on spanning trees. Assuming Arrhenius rates, this "arboreal" distribution becomes Boltzmann-like, with the energy of a tree being its total edge barrier energy. This reformulation offers a thermodynamic interpretation that smoothly generalizes equilibrium statistical mechanics and reorganizes the expression complexity: the number of distinct minimal-path entropies depends not on graph size but on the entropy production index, a measure of nonequilibrium complexity. We demonstrate the power of this reformulation by extending Hopfield's analysis of discrimination by kinetic proofreading to any graph with index 1. We derive a general formula for the error ratio and use it to show how local energy dissipation can yield optimal discrimination through global synergy.
Topics: Thermodynamics; Entropy; Physical Phenomena; Probability; Markov Chains
PubMed: 36671125
DOI: 10.1103/PhysRevE.106.064128