5 research outputs found
Traveling concentration pulses of bacteria in a generalized Keller–Segel model
We formulate a Markovian response theory for the tumble rate of a bacterium moving in a chemical field and use it in the Smoluchowski equation. Based on a multipole expansion for the one-particle distribution function and a reaction-diffusion equation for the chemoattractant field, we derive a polarization extended model, which also includes the recently discovered angle bias. In the adiabatic limit we recover a generalized Keller–Segel equation with diffusion and chemotactic coefficients that depend on the microscopic swimming parameters. Requiring the tumble rate to be positive, our model introduces an upper bound for the chemotactic drift velocity, which is no longer singular as in the original Keller–Segel model. Solving the Keller–Segel equations numerically, we identify traveling bacterial concentration pulses, for which we do not need a second, signaling chemical field nor a singular chemotactic drift velocity as demanded in earlier publications. We present an extensive study of the traveling pulses and demonstrate how their speeds, widths, and heights depend on the microscopic parameters. Most importantly, we discover a maximum number of bacteria that the pulse can sustain—the maximum carrying capacity. Finally, by tuning our parameters, we are able to match the experimental realization of the traveling bacterial pulse.DFG, 87159868, GRK 1558: Kollektive Dynamik im Nichtgleichgewicht: in kondensierter Materie und biologischen SystemenDFG, 414044773, Open Access Publizieren 2019 - 2020 / Technische Universität Berli
Quelques remarques touchant la procedure d’obtenir le consentement des patients prepares a la therapie de l’electrochoc
Electroconvulsive therapy (ЕСТ) as a medical procedure of higher risk as well as a therapy evoking certain controversies requires strict obedience to the conditions of acquiring the patient’s informed consent to the offered method of treatment. To acquire the patient’s consent it is necessary to inform him/her about the different aspects of electroconvulsive therapy. The paper stresses that in the case of ECT therapy, the spoken information given to the patient seems insufficient. It is necessary to work out a Polish questionnaire for acquiring the patient’s consent to electroconvulsive therapy and to apply it in all psychiatric institutions that carry out ECT procedures
Post-anaesthesia pulmonary complications after use of muscle relaxants (POPULAR): a multicentre, prospective observational study
Background Results from retrospective studies suggest that use of neuromuscular blocking agents during general
anaesthesia might be linked to postoperative pulmonary complications. We therefore aimed to assess whether the use
of neuromuscular blocking agents is associated with postoperative pulmonary complications.
Methods We did a multicentre, prospective observational cohort study. Patients were recruited from 211 hospitals in
28 European countries. We included patients (aged ≥18 years) who received general anaesthesia for any in-hospital
procedure except cardiac surgery. Patient characteristics, surgical and anaesthetic details, and chart review at discharge
were prospectively collected over 2 weeks. Additionally, each patient underwent postoperative physical examination
within 3 days of surgery to check for adverse pulmonary events. The study outcome was the incidence of postoperative
pulmonary complications from the end of surgery up to postoperative day 28. Logistic regression analyses were
adjusted for surgical factors and patients’ preoperative physical status, providing adjusted odds ratios (ORadj) and
adjusted absolute risk reduction (ARRadj). This study is registered with ClinicalTrials.gov, number NCT01865513.
Findings Between June 16, 2014, and April 29, 2015, data from 22803 patients were collected. The use of neuromuscular
blocking agents was associated with an increased incidence of postoperative pulmonary complications in patients who
had undergone general anaesthesia (1658 [7·6%] of 21694); ORadj 1·86, 95% CI 1·53–2·26; ARRadj –4·4%, 95% CI
–5·5 to –3·2). Only 2·3% of high-risk surgical patients and those with adverse respiratory profiles were anaesthetised
without neuromuscular blocking agents. The use of neuromuscular monitoring (ORadj 1·31, 95% CI 1·15–1·49;
ARRadj –2·6%, 95% CI –3·9 to –1·4) and the administration of reversal agents (1·23, 1·07–1·41; –1·9%, –3·2 to –0·7)
were not associated with a decreased risk of postoperative pulmonary complications. Neither the choice of sugammadex
instead of neostigmine for reversal (ORadj 1·03, 95% CI 0·85–1·25; ARRadj –0·3%, 95% CI –2·4 to 1·5) nor extubation at
a train-of-four ratio of 0·9 or more (1·03, 0·82–1·31; –0·4%, –3·5 to 2·2) was associated with better pulmonary outcomes.
Interpretation We showed that the use of neuromuscular blocking drugs in general anaesthesia is associated with an
increased risk of postoperative pulmonary complications. Anaesthetists must balance the potential benefits of
neuromuscular blockade against the increased risk of postoperative pulmonary complications