Lippia grata Essential Oil Acts Synergistically with Ampicillin Against Staphylococcus aureus and its Biofilm.

Antimicrobial resistance (AMR) presents a global challenge as microorganisms evolve to withstand the effects of antibiotics. In addition, the improper use of antibiotics significantly contributes to the AMR acceleration. Essential oils have garnered attention for their antimicrobial potential. Indeed, essential oils extracted from plants contain compounds that exhibit antibacterial activity, including against resistant microorganisms. Hence, this study aimed to evaluate the antimicrobial and antibiofilm activity of the essential oil (EO) extracted from Lippia grata and its combination with ampicillin against Staphylococcus aureus strains (ATCC 25923, ATCC 700698, and JKD6008). The plant material (leaves) was gathered in Mossoro, RN, and the EO was obtained using the hydrodistillation method with the Clevenger apparatus. The antimicrobial activity of the EO was assessed through minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assays. Antibiofilm activity was evaluated by measuring biomass using crystal violet (CV) staining, viable cell counting, and analysis of preformed biofilms. In addition, the synergistic effects of the EO in combination with ampicillin were examined by scanning electron and confocal microscopy. The EO displayed a MIC value of 2.5 mg/mL against all tested S. aureus strains and an MBC only against S. aureus JKD6008 at 2.5 mg/mL. L. grata EO caused complete biofilm inhibition at concentrations ranging from 10 to 0.312 mg/mL against S. aureus ATCC 25923 and 10 to 1.25 mg/mL against S. aureus ATCC 700698 and S. aureus JKD6008. In the viable cell quantification assay, there was a reduction in CFU ranging from 1.0 to 8.0 logs. The combination of EO with ampicillin exhibited a synergistic effect against all strains. Moreover, the combination showed a significantly inhibiting biofilm formation and eradicating preformed biofilms. Furthermore, the EO and ampicillin (individually and in combination) altered the cellular morphology of S. aureus cells. Regarding the mechanism, the results revealed that L. grata EO increased membrane permeability and caused significant membrane damage. Concerning the synergy mechanism, the results revealed that the combination of EO and ampicillin increases membrane permeability and causes considerable membrane damage, further inhibiting bacteria synergistically. The findings obtained here suggest that L. grata EO in combination with ampicillin could be a viable treatment option against S. aureus infections, including MRSA strain.

Anion-Responsive Colorimetric and Fluorometric Red-Shift in Triarylborane Derivatives: Dual Role of Phenazaborine as Lewis Acid and Electron Donor.

Photophysical modulation of triarylboranes (TABs) through Lewis acid-base interactions is a fundamental approach for sensing anions. Yet, design principles for anion-responsive TABs displaying significant red-shift in absorption and photoluminescence (PL) have remained elusive. Herein, a new strategy for modulating the photophysical properties of TABs in a red-shift mode has been presented, by using a nitrogen-bridged triarylborane (1,4-phenazaborine: PAzB) with a contradictory dual role as a Lewis acid and an electron donor. Following the strategy, PAzB derivatives connected with an electron-deficient azaaromatic have been developed, and these compounds display a distinct red-shift in their absorption and PL in response to an anion. Spectroscopic analyses and quantum chemical calculations have revealed the formation of a tetracoordinate borate upon the addition of fluoride, narrowing the HOMO-LUMO gap and enhancing the charge-transfer character in the excited state. This approach has also been demonstrated in modulating the photophysical properties of solid-state films.

Quantifying how single dose Ad26.COV2.S vaccine efficacy depends on Spike sequence features.

In the ENSEMBLE randomized, placebo-controlled phase 3 trial (NCT04505722), estimated single-dose Ad26.COV2.S vaccine efficacy (VE) was 56% against moderate to severe-critical COVID-19. SARS-CoV-2 Spike sequences were determined from 484 vaccine and 1,067 placebo recipients who acquired COVID-19. In this set of prespecified analyses, we show that in Latin America, VE was significantly lower against Lambda vs. Reference and against Lambda vs. non-Lambda [family-wise error rate (FWER) p < 0.05]. VE differed by residue match vs. mismatch to the vaccine-insert at 16 amino acid positions (4 FWER p < 0.05; 12 q-value ≤ 0.20); significantly decreased with physicochemical-weighted Hamming distance to the vaccine-strain sequence for Spike, receptor-binding domain, N-terminal domain, and S1 (FWER p < 0.001); differed (FWER ≤ 0.05) by distance to the vaccine strain measured by 9 antibody-epitope escape scores and 4 NTD neutralization-impacting features; and decreased (p = 0.011) with neutralization resistance level to vaccinee sera. VE against severe-critical COVID-19 was stable across most sequence features but lower against the most distant viruses.

Modelling the quenching effect of chloroaluminum phthalocyanine and graphene oxide interactions: implications for phototherapeutic applications.

Photodynamic therapy (PDT) and photothermal therapy (PTT) are promising candidates for cancer treatment and their efficiency can be further enhanced by using a combination of both. While chloroaluminum phthalocyanine (AlClPc) has been studied extensively as a photosensitizer in PDT, nanographene oxide (nGO) has shown promise in PTT due to its high absorption of near-infrared radiation. In this work, we investigate the energy transport between AlClPc and nGO for their combined use in phototherapies. We use density functional theory (DFT) and time-dependent DFT to analyze the electronic structure of AlClPc and its interaction with nGO. Based on experimental parameters, we model the system's morphology and implement it in Kinetic Monte Carlo (KMC) simulations to investigate the energy transfer mechanism between the compounds. Our KMC calculations show that the experimentally observed fluorescence quenching requires modeling both the energy transfer from dyes to nGO and a molecular aggregation model. Our results provide insights into the underlying mechanisms responsible for the fluorescence quenching observed in AlClPc/nGO aggregates, which could impact the efficacy of photodynamic therapy.

Photophysics of Solvated Molecules: Computational Protocol Combining Nuclear Ensemble and Nonequilibrium State-Specific Solvation Methods.

Efficient calculations of the photophysical properties of molecules are essential for both understanding experimental results and accelerating materials discovery through computational simulations. However, to achieve accurate results, the effects of the surrounding medium must be taken into account. Here, we present a computational protocol that combines the nuclear ensemble method with a nonequilibrium state-specific polarizable continuum model to simulate absorption, fluorescence, phosphorescence, and intersystem crossing processes. Additionally, we introduced an extrapolation strategy that enables predictions for multiple solvents without incurring additional computational costs. We demonstrate the method's effectiveness by modeling the photophysical properties of a molecule that exhibits thermally activated delayed fluorescence, showcasing how these properties vary with solvent polarity. We also provide insight into the relationship between the solvent and photophysics by using ensemble analysis to rationalize simulation results. Furthermore, we introduce a metric for the intensity of the charge transfer character of electronic states and demonstrate how vibrations can significantly mix the electronic character of excited states. Overall, this work presents a computational approach that offers new insights into the photophysics of molecules and has the potential to advance materials discovery.

Quantifying how single dose Ad26.COV2.S vaccine efficacy depends on Spike sequence features.

It is of interest to pinpoint SARS-CoV-2 sequence features defining vaccine resistance. In the ENSEMBLE randomized, placebo-controlled phase 3 trial, estimated single-dose Ad26.COV2.S vaccine efficacy (VE) was 56% against moderate to severe-critical COVID-19. SARS-CoV-2 Spike sequences were measured from 484 vaccine and 1,067 placebo recipients who acquired COVID-19 during the trial. In Latin America, where Spike diversity was greatest, VE was significantly lower against Lambda than against Reference and against all non-Lambda variants [family-wise error rate (FWER) p < 0.05]. VE also differed by residue match vs. mismatch to the vaccine-strain residue at 16 amino acid positions (4 FWER p < 0.05; 12 q-value ≤ 0.20). VE significantly decreased with physicochemical-weighted Hamming distance to the vaccine-strain sequence for Spike, receptor-binding domain, N-terminal domain, and S1 (FWER p < 0.001); differed (FWER ≤ 0.05) by distance to the vaccine strain measured by 9 different antibody-epitope escape scores and by 4 NTD neutralization-impacting features; and decreased (p = 0.011) with neutralization resistance level to vaccine recipient sera. VE against severe-critical COVID-19 was stable across most sequence features but lower against viruses with greatest distances. These results help map antigenic specificity of in vivo vaccine protection.

Infective Endocarditis due to Non-HACEK Gram-Negative Bacilli: Clinical Characteristics and Risk Factors from a Prospective Multicenter Brazilian Cohort.

Background: Non-HACEK Gram-negative bacilli (NGNB) infective endocarditis (IE) has a growing frequency. We aimed to describe cases of NGNB IE and find associated risk factors. Methods: We conducted a prospective observational study of consecutive patients with definitive IE according to the modified Duke criteria in four institutions in Brazil. Results: Of 1154 adult patients enrolled, 38 (3.29%) had IE due to NGNB. Median age was 57 years, males predominated, accounting for 25/38 (65.8%). Most common etiologies were Pseudomonas aeruginosa and Klebsiella spp. (8 episodes, 21% each). Worsening heart failure occurred in 18/38 (47.4%). Higher prevalence of embolic events was found (55,3%), mostly to the central nervous system 7/38 (18.4%). Vegetations were most commonly on aortic valves 17/38 (44.7%). Recent healthcare exposure was found in 52.6% and a central venous catheter (CVC) in 13/38 (34.2%). Overall mortality was 19/38 (50%). Indwelling CVC (OR 5.93; 95% CI, 1.29 to 27.3; p = 0.017), hemodialysis (OR 16.2; 95% CI, 1.78 to 147; p = 0.008) and chronic kidney disease (OR 4.8; 95% IC, 1.2 to 19.1, p = 0.049) were identified as risk factors for mortality. Conclusions: The rate of IE due to NGNB was similar to that in previous studies. Enterobacterales and P. aeruginosa were the most common etiologies. NGNB IE was associated with central venous catheters, prosthetic valves, intracardiac devices and hemodialysis and had a high mortality rate.

Immune correlates analysis of the ENSEMBLE single Ad26.COV2.S dose vaccine efficacy clinical trial.

Measuring immune correlates of disease acquisition and protection in the context of a clinical trial is a prerequisite for improved vaccine design. We analysed binding and neutralizing antibody measurements 4 weeks post vaccination as correlates of risk of moderate to severe-critical COVID-19 through 83 d post vaccination in the phase 3, double-blind placebo-controlled phase of ENSEMBLE, an international randomized efficacy trial of a single dose of Ad26.COV2.S. We also evaluated correlates of protection in the trial cohort. Of the three antibody immune markers we measured, we found most support for 50% inhibitory dilution (ID50) neutralizing antibody titre as a correlate of risk and of protection. The outcome hazard ratio was 0.49 (95% confidence interval 0.29, 0.81; P = 0.006) per 10-fold increase in ID50; vaccine efficacy was 60% (43%, 72%) at non-quantifiable ID50 (<2.7 IU50 ml-1) and increased to 89% (78%, 96%) at ID50 = 96.3 IU50 ml-1. Comparison of the vaccine efficacy by ID50 titre curves for ENSEMBLE-US, the COVE trial of the mRNA-1273 vaccine and the COV002-UK trial of the AZD1222 vaccine supported the ID50 titre as a correlate of protection across trials and vaccine types.

Diabatic Decomposition Perspective on the Role of Charge Transfer and Local Excitations in Thermally Activated Delayed Fluorescence.

Thermally activated delayed fluorescence (TADF) is a phenomenon that relies on the upconversion of triplet excitons to singlet excitons by means of reverse intersystem crossing (rISC). It has been shown both experimentally and theoretically that the TADF mechanism depends on the interplay between charge transfer and local excitations. However, the difference between the diabatic and adiabatic character of the involved excited states is rarely discussed in the literature. Here we develop a diabatization procedure to implement a four-state model Hamiltonian to a set of TADF molecules. We provide physical interpretations of the Hamiltonian elements and show their dependence on the electronic state of the equilibrium geometry. We also demonstrate how vibrations affect the TADF efficiency by modifying the diabatic decomposition of the molecule. Finally, we provide a simple model that connects the diabatic Hamiltonian to the electronic properties relevant to TADF and show how this relationship translates into different optimization strategies for rISC, fluorescence, and overall TADF performance.

Comparative study of thermally activated delayed fluorescent properties of donor-acceptor and donor-acceptor-donor architectures based on phenoxazine and dibenzo[a,j]phenazine.

A new thermally activated delayed fluorescence (TADF) compound based on a donor-acceptor (D-A) architecture (D = phenoxazine; A = dibenzo[a,j]phenazine) has been developed, and its photophysical properties were characterized. The D-A compound is applicable as an emitting material for efficient organic light-emitting diodes (OLEDs), and its external quantum efficiency (EQE) exceeds the theoretical maximum of those with prompt fluorescent emitters. Most importantly, comparative study of the D-A molecule and its D-A-D counterpart from the viewpoints of the experiments and theoretical calculations revealed the effect of the number of the electron donor on the thermally activated delayed fluorescent behavior.

Dual-photofunctional organogermanium compound based on donor-acceptor-donor architecture.

A dual-photofunctional organogermanium compound based on a donor-acceptor-donor architecture that exhibits thermally activated delayed fluorescence and mechano-responsive luminochromism has been developed. The developed compound was successfully applied as an emitter for efficient organic light-emitting diodes.

Immune Correlates Analysis of a Single Ad26.COV2.S Dose in the ENSEMBLE COVID-19 Vaccine Efficacy Clinical Trial.

Anti-spike IgG binding antibody, anti-receptor binding domain IgG antibody, and pseudovirus neutralizing antibody measurements four weeks post-vaccination were assessed as correlates of risk of moderate to severe-critical COVID-19 outcomes through 83 days post-vaccination and as correlates of protection following a single dose of Ad26.COV2.S COVID-19 vaccine in the placebo-controlled phase of ENSEMBLE, an international, randomized efficacy trial. Each marker had evidence as a correlate of risk and of protection, with strongest evidence for 50% inhibitory dilution (ID50) neutralizing antibody titer. The outcome hazard ratio was 0.49 (95% confidence interval 0.29, 0.81; p=0.006) per 10-fold increase in ID50; vaccine efficacy was 60% (43, 72%) at nonquantifiable ID50 (< 2.7 IU50/ml) and rose to 89% (78, 96%) at ID50 = 96.3 IU50/ml. Comparison of the vaccine efficacy by ID50 titer curves for ENSEMBLE-US, the COVE trial of the mRNA-1273 vaccine, and the COV002-UK trial of the AZD1222 vaccine supported consistency of the ID50 titer correlate of protection across trials and vaccine types.

Health knowledge, health behaviors and attitudes during pandemic emergencies: A systematic review.

BACKGROUND: People with good health knowledge present a conceptual and objective appropriation of general and specific health topics, increasing their probability to express health protection and prevention measures. The main objective of this study was to conduct a rapid systematic review about the effects of health knowledge on the adoption of health behaviors and attitudes in populations under pandemic emergencies. METHODS: A systematic review was performed according to PRISMA checklist and the Cochrane method for rapid systematic reviews. Studies searches were performed in APA PsycNet, Embase, Cochrane Library and PubMed Central. Studies published between January 2009 and June 2020 and whose primary results reported a measure of interaction between health knowledge, health attitudes and behaviors in population groups during pandemics were included. A review protocol was recorded in PROSPERO (CRD42020183347). RESULTS: Out of a total of 5791 studies identified in the databases, 13 met the inclusion criteria. The included studies contain a population of 26099 adults, grouped into cohorts of health workers, university students, clinical patients, and the general population. Health knowledge has an important influence on the adoption of health behaviors and attitudes in pandemic contexts. CONCLUSIONS: The consolidation of these preventive measures favors the consolidation of public rapid responses to infection outbreaks. Findings of this review indicate that health knowledge notably favors adoption of health behaviors and practices. Therefore, health knowledge based on clear and objective information would help them understand and adopt rapid responses to face a pandemic.

Unified Framework for Photophysical Rate Calculations in TADF Molecules.

One of the challenges in organic light-emitting diodes research is finding ways to increase device efficiency by making use of the triplet excitons that are inevitably generated in the process of electroluminescence. One way to do so is by thermally activated delayed fluorescence (TADF), a process in which triplet excitons undergo upconversion to singlet states, allowing them to relax radiatively. The discovery of this phenomenon has ensued a quest for new materials that are able to effectively take advantage of this mechanism. From a theoretical standpoint, this requires the capacity to estimate the rates of the various processes involved in the photophysics of candidate molecules, such as intersystem crossing, reverse intersystem crossing, fluorescence, and phosphorescence. Here, we present a method that is able to, within a single framework, compute all of these rates and predict the photophysics of new molecules. We apply the method to two TADF molecules and show that results compare favorably with other theoretical approaches and experimental results. Finally, we use a kinetic model to show how the calculated rates act in concert to produce different photophysical behavior.

Assessing the effects of increasing conjugation length on exciton diffusion: from small molecules to the polymeric limit.

Organic solar cells (OSC) generally contain long-chain π-conjugated polymers as donor materials, but, more recently, small-molecule donors have also attracted considerable attention. The nature of these compounds is of crucial importance concerning the various processes that determine device performance, among which singlet exciton diffusion is one of the most relevant. The efficiency of the diffusion mechanism depends on several aspects, from system morphology to electronic structure properties, which vary importantly with molecular size. In this work, we investigated the effects of conjugation length on the exciton diffusion length through electronic structure calculations and an exciton diffusion model. By applying extrapolation procedures to thiophene and phenylene vinylene oligomer series, we investigate their electronic and optical properties from the small-molecule point of view to the polymeric limit. Several properties are calculated as a function of oligomer size, including transition energies, absorption and emission spectra, reorganization energies, exciton coupling and Förster radii. Finally, an exciton diffusion model is used to estimate diffusion lengths as a function of oligomer size and for the polymeric limit showing agreement with experimental data. Results also show that longer conjugation lengths correlate with longer exciton diffusion lengths in spite of also being associated with shorter exciton lifetimes.

Is there an association between prostate-specific antigen and androgen levels in 46, XX patients with congenital adrenal hyperplasia?

INTRODUCTION: Congenital adrenal hyperplasia (CAH), a genetic disease characterized by defective cortisol synthesis and excessive levels of sex hormones, can cause precocious puberty in both sexes in untreated individuals and virilization in female patients with a 46, XX karyotype. The female paraurethral (Skene's) gland has been reported as prostate analogous. Growth of prostate tissue is associated with androgen production; therefore, prostate-specific antigen (PSA) levels may represent a marker of virilization in 46, XX patients with CAH. OBJECTIVES: To describe PSA levels in 46, XX patients and evaluate whether higher PSA levels are associated with androgenization and the severity of the disease. STUDY DESIGN: Sixty-six patients with CAH and a 46, XX karyotype were included, irrespective of age. Serum PSA, testosterone, 17-hydroxyprogesterone (17-OHP) and androstenedione levels were measured. Patients' age, age at diagnosis, forms of the disease, Prader classification, bone age assessment, sex of rearing, surgery, and the presence of clinical complications were obtained from their medical records. RESULTS: The mean age of patients was 11.45 ± 10.74 years. Forty-three patients (65%) were diagnosed neonatally at a median of 0.08 years (mean 1.47 ± 2.34 years), with registers of 17-OHP measurements (Guthrie test) being available in 51%. Testosterone, 17-OHP and androstenedione were significantly high. PSA was detectable in 25% of cases (levels >0.01 ng/ml), with a mean of 0.03 ± 0.09 ng/ml, and only in patients over five years of age. A correlation was found between PSA and age (p < 0.001), age at diagnosis (p = 0.002), testosterone (p = 0.001) and androstenedione (p = 0.023). There was no correlation between PSA and the forms of CAH or Prader classification. A sub-analysis of the patients over five years of age in whom PSA was detectable also showed that there was a correlation between PSA (p < 0.05) and age at analysis, age at diagnosis, testosterone and androstenedione levels. DISCUSSION: Limitations of this study include the small sample size due to the rareness of the disease, its retrospective nature, the absence of a control group, the fact that the sample was selected at two referral centers, which could have resulted in a selection bias, and the use of different reference values in the different laboratories conducting the PSA tests. CONCLUSIONS: PSA is detectable in 25% of 46, XX patients with CAH, only after five years of age. PSA level increases significantly with age, age at diagnosis, and testosterone and androstenedione levels, confirming a correlation between PSA levels and elevated androgen levels.

Charge localization and hopping in a topologically engineered graphene nanoribbon.

Graphene nanoribbons (GNRs) are promising quasi-one-dimensional materials with various technological applications. Recently, methods that allowed for the control of GNR's topology have been developed, resulting in connected nanoribbons composed of two distinct armchair GNR families. Here, we employed an extended version of the Su-Schrieffer-Heeger model to study the morphological and electronic properties of these novel GNRs. Results demonstrated that charge injection leads to the formation of polarons that localize strictly in the 9-AGNRs segments of the system. Its mobility is highly impaired by the system's topology. The polaron displaces through hopping between 9-AGNR portions of the system, suggesting this mechanism for charge transport in this material.

Mortality caused by venomous animals in Venezuela (2000-2009): A new epidemiological pattern / Mortalidad causada por animales venenosos en Venezuela (2000-2009): nuevo patrón epidemiológico.

Introduction: Injuries by venomous animals frequently occur in impoverished communities with limited access to health services. They are considered neglected diseases that stand out as important causes of morbidity and mortality in various countries, including Venezuela. Objective: To assess mortalities resulting from contact with venomous animals in Venezuela from 2000 to 2009 (X20-X29 series). Materials and Methods: The data were obtained from the annual mortality records of the Venezuelan Ministry of Health. Results: From 2000-2009, 759 fatalities were recorded with the greatest number taking place in 2009. Snakebites (n=323; 42.6%) accounted for the largest percentage of envenomation-related deaths in that period, followed by hymenopteran stings (n=170; 22.4%), centipede bites (n=106; 14.0%), and scorpion stings (n=76; 10.0%). The median value of envenomation-related deaths per 100,000 inhabitants (period 2000-2009) was 0.285: 0.120 corresponded to snakebites, 0.065 to hymenopteran stings, 0.035 to centipede bites, and 0.025 to scorpion stings. Conclusions: Taking into account previous records of animal envenomations in Venezuela, we provided evidence for a shift in the pattern of mortality. Deaths due to centipede bites have increased, making it the third leading cause of envenomation-related mortality in Venezuela. Scorpionism, on the other hand, has declined to the fourth most common cause of fatal envenomations in the country.

Introducción. Los accidentes causados por animales venenosos ocurren con mucha frecuencia en comunidades pobres con acceso limitado a los servicios de salud. Se les consideran enfermedades desatendidas y son una de las causas importantes de morbimortalidad en varias naciones del mundo, incluida Venezuela. Objetivo. Evaluar la mortalidad por contacto traumático con animales venenosos (serie X20-X29) en Venezuela en el periodo de 2000 a 2009. Materiales y métodos. Los datos se obtuvieron de los anuarios de mortalidad del Ministerio de Salud. Resultados. Se registraron 759 decesos, la mayoría de ellos en el 2009. La primera causa fue la mordedura de serpientes (n=323; 42,6 %), seguida por la picadura de himenópteros (n=170; 22,4 %), la mordedura de centípedos (n=106; 14,0 %) y la picadura de escorpiones (n=76; 10,0 %). La mediana de la tasa de mortalidad general para el periodo fue de 0,285 fallecidos por 100.000 habitantes, en tanto que, por grupo específico, fue de 0,120 para ofidios, de 0,065 para himenópteros, de 0,035 para centípedos y de 0,025 para escorpiones. Conclusión. Al comparar estos datos con los antecedentes históricos, se evidenció la modificación del patrón de mortalidad en el país caracterizada por un aumento significativo de los decesos por centípedos, tercera causa de muerte, lo que reubica la picadura de escorpiones como la cuarta causa de mortalidad.

Mortalidad causada por animales venenosos en Venezuela (2000-2009): nuevo patrón epidemiológico / Mortality caused by venomous animals in Venezuela (2000-2009): A new epidemiological pattern

Resumen | Introducción. Los accidentes causados por animales venenosos ocurren con mucha frecuencia en comunidades pobres con acceso limitado a los servicios de salud. Se les consideran enfermedades desatendidas y son una de las causas importantes de morbimortalidad en varias naciones del mundo, incluida Venezuela. Objetivo. Evaluar la mortalidad por contacto traumático con animales venenosos (serie X20-X29) en Venezuela en el periodo de 2000 a 2009. Materiales y métodos. Los datos se obtuvieron de los anuarios de mortalidad del Ministerio de Salud. Resultados. Se registraron 759 decesos, la mayoría de ellos en el 2009. La primera causa fue la mordedura de serpientes (n=323; 42,6 %), seguida por la picadura de himenópteros (n=170; 22,4 %), la mordedura de centípedos (n=106; 14,0 %) y la picadura de escorpiones (n=76; 10,0 %). La mediana de la tasa de mortalidad general para el periodo fue de 0,285 fallecidos por 100.000 habitantes, en tanto que, por grupo específico, fue de 0,120 para ofidios, de 0,065 para himenópteros, de 0,035 para centípedos y de 0,025 para escorpiones. Conclusión. Al comparar estos datos con los antecedentes históricos, se evidenció la modificación del patrón de mortalidad en el país caracterizada por un aumento significativo de los decesos por centípedos, tercera causa de muerte, lo que reubica la picadura de escorpiones como la cuarta causa de mortalidad.

Abstract | Introduction: Injuries by venomous animals frequently occur in impoverished communities with limited access to health services. They are considered neglected diseases that stand out as important causes of morbidity and mortality in various countries, including Venezuela. Objective: To assess mortalities resulting from contact with venomous animals in Venezuela from 2000 to 2009 (X20-X29 series). Materials and Methods: The data were obtained from the annual mortality records of the Venezuelan Ministry of Health. Results: From 2000-2009, 759 fatalities were recorded with the greatest number taking place in 2009. Snakebites (n=323; 42.6%) accounted for the largest percentage of envenomation-related deaths in that period, followed by hymenopteran stings (n=170; 22.4%), centipede bites (n=106; 14.0%), and scorpion stings (n=76; 10.0%). The median value of envenomation-related deaths per 100,000 inhabitants (period 2000-2009) was 0.285: 0.120 corresponded to snakebites, 0.065 to hymenopteran stings, 0.035 to centipede bites, and 0.025 to scorpion stings. Conclusions: Taking into account previous records of animal envenomations in Venezuela, we provided evidence for a shift in the pattern of mortality. Deaths due to centipede bites have increased, making it the third leading cause of envenomation-related mortality in Venezuela. Scorpionism, on the other hand, has declined to the fourth most common cause of fatal envenomations in the country.

Kinetic Monte Carlo model for the COVID-19 epidemic: Impact of mobility restriction on a COVID-19 outbreak.

As the coronavirus disease 2019 (COVID-19) spreads worldwide, epidemiological models have been employed to evaluate possible scenarios and gauge the efficacy of proposed interventions. Considering the complexity of disease transmission dynamics in cities, stochastic epidemic models include uncertainty in their treatment of the problem, allowing the estimation of the probability of an outbreak, the distribution of epidemic magnitudes, and their expected duration. In this sense, we propose a kinetic Monte Carlo epidemic model that focuses on demography and on age-structured mobility data to simulate the evolution of the COVID-19 outbreak in the capital of Brazil, Brasilia, under several scenarios of mobility restriction. We show that the distribution of epidemic outcomes can be divided into short-lived mild outbreaks and longer severe ones. We demonstrate that quarantines have the effect of reducing the probability of a severe outbreak taking place but are unable to mitigate the magnitude of these outbreaks once they happen. Finally, we present the probability of a particular trajectory in the epidemic progression resulting in a massive outbreak as a function of the cumulative number of cases at the end of each quarantine period, allowing for the estimation of the risk associated with relaxing mobility restrictions at a given time.