122 research outputs found

    Curvature-coupling dependence of membrane protein diffusion coefficients

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    We consider the lateral diffusion of a protein interacting with the curvature of the membrane. The interaction energy is minimized if the particle is at a membrane position with a certain curvature that agrees with the spontaneous curvature of the particle. We employ stochastic simulations that take into account both the thermal fluctuations of the membrane and the diffusive behavior of the particle. In this study we neglect the influence of the particle on the membrane dynamics, thus the membrane dynamics agrees with that of a freely fluctuating membrane. Overall, we find that this curvature-coupling substantially enhances the diffusion coefficient. We compare the ratio of the projected or measured diffusion coefficient and the free intramembrane diffusion coefficient, which is a parameter of the simulations, with analytical results that rely on several approximations. We find that the simulations always lead to a somewhat smaller diffusion coefficient than our analytical approach. A detailed study of the correlations of the forces acting on the particle indicates that the diffusing inclusion tries to follow favorable positions on the membrane, such that forces along the trajectory are on average smaller than they would be for random particle positions.Comment: 16 pages, 8 figure

    A Medicinal Chemist’s Guide to Molecular Interactions

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    Predictors of voluntary and compulsory admissions after psychiatric emergency consultation in youth

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    As hospital beds are scarce, and emergency admissions to a psychiatric ward are major life-events for children and adolescents, it is essential to have insight into the decision-making process that leads to them. To identify potentially modifiable factors, we, therefore, studied the contextual and clinical characteristics associated with the voluntary and compulsory emergency admission of minors. We used registry data (2008–2017) on 1194 outpatient emergencies involving children aged 6–18 who had been referred to the mobile psychiatric emergency service in two city areas in The Netherlands. Demographic and contextual factors were collected, as well as clinical characteristics including diagnoses, psychiatric history, Global Assessment of Functioning (GAF), and the Severity of Psychiatric Illness (SPI) scale. Logistic regression analyses were used to identify factors that predict voluntary or compulsory admission. Of 1194 consultations, 227 (19.0%) resulted in an admission, with 137 patients (11.5%) being admitted voluntarily and 90 (7.5%) compulsorily. Independently of legal status, the following characteristics were associated with admission: severity of psychiatric symptoms, consultation outside the patient’s home, and high levels of family disruption. Relative to voluntary admission, compulsory admission was associated with more severe psychiatric problems, higher suicide risk, and prior emergency compulsory admission. Two potentially modifiable factors were associated with psychiatric emergency admission: the place where patients were seen for consultation, and the presence of family problems. Psychiatric emergency admissions may be reduced if, whenever possible, minors are seen in their homes and if a system-oriented approach is used
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