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Introduction. Efforts to understand the burden of antibiotic use in low- and middle-income countries such as Brazil are essential for developing strategies that are effective and appropriate in the context of endemic multidrug-resistant organisms. Aim. This study aims to determine antimicrobial-prescribing practices among patients hospitalized in intensive care units (ICUs) for adults in Brazil. Methodology. A 1-day point prevalence multicentre survey was conducted in 58 adult ICUs across the five regions of Brazil. The institutions were categorized according to their type and size. Detailed antimicrobial prescription data were prospectively provided to all patients hospitalized on the day of data collection. Results. A total of 620 patients were included in the study, of whom 63.9% were receiving at least one antimicrobial. Of these, 34.6% were treated for an infection, but only 39.9% of the cases were based on microbiological criteria. Empirical treatment was applied to 72.3% of the patients. Significant differences in antibiotic usage were observed across the different hospitals included in the study. Overall, treatment was most commonly directed towards pneumonia (51.8%) and bloodstream infections (29.6%). Glycopeptides (19.4%) and carbapenems (18.5%) were the most prescribed in teaching hospitals, while in non-teaching hospitals, carbapenems (17.8%) and broad-spectrum cephalosporins (16.8%) were most frequently used. Conclusion. Our study reveals alarming data on antibiotic use in adult ICUs in Brazil, with high frequencies of severe healthcare-associated infections acquired in these units, where patients are frequently subjected to empirical treatment.

Introduction: Bipolar disorder (BD) is a chronic pathology that is associated with several impairments throughout a patient's life, including decreased sexual function. Despite the importance in quality of life (QoL), functionality and medication adherence, it is still little investigated in these patients., Objective: To compare the sexual function of patients with Bipolar Disorder type I (BD-I), in remission, with healthy controls (HC) and to investigate the clinical and socio-demographic characteristics associated with sexual function in these individuals. Also, to assess the QoL in patients with and without sexual dysfunction (SD)., Methods: Cross-sectional study with 132 patients with BD-I in euthymic phase and 61 HCs from an outpatient clinic. All the participants were evaluated through the Arizona Sexual Scale (ASEX) and the brief version of the World Health Organization Quality of Life Assessment (WHOQoL-BREF). The patients with BD-I were compared with the HCs. The patients were divided into two groups: the ones diagnosed with SD and the ones without it., Results: The patients with BD-I had higher rates of SD (42.4%) compared to the HCs (16.4%) (OR 3.67, 95% CI 1.55 - 8.67; p=0.003). SD in patients was associated with being women (p=0.001), older age (p=0.003) and having a longer duration of untreated illness (p=0.010). Patients with SD had worse QoL scores compared to those without SD., Conclusion: Patients with BD-I have a high prevalence of SD and this was associated with worse QoL scores in all domains., Competing Interests: No conflicts of interest declared concerning the publication of this article.

P21 is a protein secreted by all forms of Trypanosoma cruzi ( T. cruzi ) with recognized biological activities determined in studies using the recombinant form of the protein. In our recent study, we found that the ablation of P21 gene decreased Y strain axenic epimastigotes multiplication and increased intracellular replication of amastigotes in HeLa cells infected with metacyclic trypomastigotes. In the present study, we investigated the effect of P21 in vitro using C2C12 cell lines infected with tissue culture-derived trypomastigotes (TCT) of wild-type and P21 knockout (TcP21 -/- ) Y strain, and in vivo using an experimental model of T. cruzi infection in BALB/c mice. Our in-vitro results showed a significant decrease in the host cell invasion rate by TcP21 -/- parasites as measured by Giemsa staining and cell count in bright light microscope. Quantitative polymerase chain reaction (qPCR) analysis showed that TcP21 -/- parasites multiplied intracellularly to a higher extent than the scrambled parasites at 72h post-infection. In addition, we observed a higher egress of TcP21 -/- trypomastigotes from C2C12 cells at 144h and 168h post-infection. Mice infected with Y strain TcP21 -/- trypomastigotes displayed higher systemic parasitemia, heart tissue parasite burden, and several histopathological alterations in heart tissues compared to control animals infected with scrambled parasites. Therewith, we propose that P21 is important in the host-pathogen interaction during invasion, cell multiplication, and egress, and may be part of the mechanism that controls parasitism and promotes chronic infection without patent systemic parasitemia., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Silveira, Uombe, Velikkakam, Borges, Teixeira, de Almeida, Torres, Pereira, de Souza, Teixeira, Servato, Silva, Mineo, Ribas, Mortara, da Silveira and da Silva.)

That incoherent scattering from protiated molecular liquids adds a constant background to the measured scattering intensity is well-known, but less appreciated is the fact that coherent scattering is also induced by the presence of hydrogen in a deuterated liquid. In fact, the scattering intensity can be very sensitive, in the small-q region, with respect to the amounts and distribution of residual H in the system. We used 1,4-dioxane liquid to demonstrate that the partial structure factors of the HD and DD atom pairs contribute significantly to intermolecular scattering and that uncertainty in the extent of deuteration account for discrepancies between simulations and measurements. Both contributions to uncertainty have similar magnitudes: scattering interference of the hydrogen-deuterium pair, and complementary interference from the deuterium-deuterium pair by virtue of chemical inhomogeneity. This situation arises in practice since deuteration of liquids is often 99% or less. A combined experimental and extensive computational study of static thermal neutron scattering of 1,4-dioxane demonstrates the foregoing. We show, through simulations, that the reason for the differences is the content of protiated dioxane (vendors quote 1%). We estimate that up to 5% (at 298 K and at 343 K) protiated molar fraction may be involved in generating the scattering differences. Finally, we find that the particular distribution of hydrogen in the protiated molecules affects the results significantly; here, we considered molecules to be either fully protiated or fully deuterated. This scenario best reconciles the computational and experimental results, and leads us to speculate that the deuteration synthesis process tends to leave a molecule either fully deuterated or fully protiated. Although we have used 1,4-dioxane as a model liquid, the effects described in this study extend to similar liquids, and similar systematic experimental/computational studies can be performed to either understand measurements or calibrate/validate molecular dynamics models.

Molecular dynamics simulations of tri-n-butyl-phosphate (TBP)/n-dodecane mixture in the liquid phase have been carried out using two recently developed TBP force field models (J. Phys. Chem. B 2012, 116, 305) in combination with the all-atom optimized potentials for liquid simulations (OPLS-AA) force field model for n-dodecane. Specifically, the electric dipole moment of TBP, mass density of the mixture, and the excess volume of mixing were computed with TBP mole fraction ranging from 0 to 1. It is found that the aforementioned force field models accurately predict the mass density of the mixture in the entire mole fraction range. Commensurate with experimental measurements, the electric dipole moment of the TBP was found to slightly increase with the mole fraction of TBP in the mixture. Also, in accord with experimental data, the excess volume of mixing is positive in the entire mole fraction range, peaking at TBP mole fraction range 0.3-0.5. Finally, a close examination of the spatial pair correlation functions between TBP molecules, and between TBP and n-dodecane molecules, revealed formation of TBP dimers through self-association at close distance, a phenomenon with ample experimental evidence.

Molecular dynamics simulations were performed to investigate water extraction into a solution of 30 vol % tri-n-butylphosphate (TBP) in n-dodecane. Our computational results indicate that the TBP electric dipole moment has a significant effect on the predicted water solubility. A larger TBP dipole moment decreases the aqueous-organic interfacial tension, leading to increased roughness of the aqueous-organic interface. Interfacial roughness disrupts the interfacial water hydrogen bonding structure, resulting in a presence of dangling water molecules at the interface. The increased interfacial roughness enhances the probability of water molecules breaking away from the aqueous phase and migrating into the organic bulk phase. By varying the atomic partial charges of the TBP molecules to reproduce a dipole moment close to the experimentally measured value, we were able to predict water solubility in close agreement with experimental measurements. In addition, our simulation results reveal the detailed molecular mechanism of the water extraction process, and the various structural forms of water molecules both at the interface and in the bulk organic phase.

A comprehensive molecular dynamics simulation study of n-alkanes using the optimized potential for liquid simulation with all-atoms (OPLS-AA) force field at ambient condition has been performed. Our results indicate that while simulations with the OPLS-AA force field accurately predict the liquid state mass density for n-alkanes with carbon number equal or less than 10, for n-alkanes with carbon number equal or exceeding 12, the OPLS-AA force field with the standard scaling factor for the 1-4 intramolecular Van der Waals and electrostatic interaction gives rise to a quasi-crystalline structure. We found that accurate predictions of the liquid state properties are obtained by successively reducing the aforementioned scaling factor for each increase of the carbon number beyond n-dodecane. To better understand the effects of reducing the scaling factor, its influence on the torsion potential profile, and the corresponding gauche-trans conformer distribution, heat of vaporization, melting point, and self-diffusion coefficient for n-dodecane were investigated. This relatively simple procedure enables more accurate predictions of the thermo-physical properties of longer n-alkanes.

Molecular dynamics (MD) simulations were conducted to compare the performance of four force fields in predicting thermophysical properties of tri-n-butyl-phosphate (TBP) in the liquid phase. The intramolecular force parameters used were from the Assisted Model Building with Energy Refinement (AMBER) force field model. The van der Waals parameters were based on either the AMBER or the Optimized Potential for Liquid Simulation (OPLS) force fields. The atomic partial charges were either assigned by performing quantum chemistry calculations or utilized previously published data, and were scaled to approximate the average experimental value of the electric dipole moment. Canonical ensemble computations based on the aforementioned parameters were performed near atmospheric pressure and temperature to obtain the electric dipole moment, mass density, and self-diffusion coefficient. In addition, the microscopic structure of the liquid was characterized via pair correlation functions between selected atoms. It has been demonstrated that the electric dipole moment can be approximated within 1% of the average experimental value by virtue of scaled atomic partial charges. The liquid mass density can be predicted within 0.5-1% of its experimentally determined value when using the corresponding charge scaling. However, in all cases, the predicted self-diffusion coefficient is significantly smaller than a commonly quoted experimental measurement; this result is qualified by the fact that the uncertainty of the experimental value was not available.

Liquid-liquid extraction of uranyl is studied by conducting atomistic molecular dynamics simulation using quantum chemistry calibrated force fields via restrained electrostatic potential fitting of atomic forces. The simulations depict the migration of uranyl nitrate complexes from the aqueous-organic interface into the tri-n-butyl phosphate (TBP)/dodecane organic phase, in the form of UO(2)(NO(3))(2)·H(2)O·2TBP and UO(2)(NO(3))(2)·3TBP. The migration process is characterized by the gradual breaking of all the hydrogen bonds between the complex and the water molecules at the interface. Moreover, our simulation results suggest that the experimentally observed complex UO(2)(NO(3))(2)·2TBP is formed after the migration of the aforementioned complexes into the organic phase by means of a reorganization of the nitrate binding mode from mono to bidentate which removes the excess oxygen atoms bound to uranyl.