A stochastic model of catalytic reaction networks in protocells

Protocells are supposed to have played a key role in the self-organizing processes leading to the emergence of life. Existing models either (i) describe protocell architecture and dynamics, given the existence of sets of collectively self-replicating molecules for granted, or (ii) describe the emergence of the aforementioned sets from an ensemble of random molecules in a simple experimental setting (e.g. a closed system or a steady-state flow reactor) that does not properly describe a protocell. In this paper we present a model that goes beyond these limitations by describing the dynamics of sets of replicating molecules within a lipid vesicle. We adopt the simplest possible protocell architecture, by considering a semi-permeable membrane that selects the molecular types that are allowed to enter or exit the protocell and by assuming that the reactions take place in the aqueous phase in the internal compartment. As a first approximation, we ignore the protocell growth and division dynamics. The behavior of catalytic reaction networks is then simulated by means of a stochastic model that accounts for the creation and the extinction of species and reactions. While this is not yet an exhaustive protocell model, it already provides clues regarding some processes that are relevant for understanding the conditions that can enable a population of protocells to undergo evolution and selection.Comment: 20 pages, 5 figure

Involuntary Hospitalizations in an Italian Acute Psychiatric Ward: A 6-Year Retrospective Analysis

Purpose: We evaluated the differences between demographic (age, sex, nationality, employment, housing, schooling, support administrator), clinical (hospitalization reason, aggressive behaviour, length of hospitalization, psychiatric diagnosis and comorbidities, psychiatric medications, discharge destination, “revolving door” hospitalizations) and environmental (pre-and pandemic period) variables in voluntary (VHs) and involuntary hospitalizations (IHs) in an acute psychiatric ward during a 6-year period. Patients and Methods: We retrospectively collected the selected variables concerning the hospitalizations of subjects over 18 years of age in the Service for Psychiatric Diagnosis and Care of Mental Health and Drug Abuse Department in Modena from 01/01/2017 to 31/12/2022. Results: We observed a progressive and sharp reduction in the number of VHs (n = 1800; 61.41%) during the pandemic and a stability of IHs (n = 1131; 38.59%), which in 2022 became prevalent. We highlighted the following differences between VHs and IHs: an increase in hospitalization length in IHs (14.25 mean days ± 15.89 SD) in comparison with VHs (8.78 mean days ± 13.88 SD), which increased more during the pandemic; an increase in aggressive behavior in IHs, especially during the pandemic (Pearson Chi2 = 90.80; p = 0.000); a prevalence of schizophrenia and bipolar disorders (Pearson Chi2 = 283.63; p = 0.000) and more frequent maladaptive social conditions among subjects in IHs. Conclusion: During the 6-year observation period, we underscored a trend of increasingly reduced recourse to VHs, whereas IHs increased even in the pandemic. Our results suggest that IHs in Psychiatry represented an extreme measure for treating the most severe psychopathological situations such as schizophrenia and bipolar disorders, characterized by aggressive behaviour and precarious social conditions, which needed longer stay than VHs, especially during the pandemic