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Abstract Background This review is an update of the previous study aiming to identify the available evidence related to physical activity (PA) in the context of the coronavirus disease (COVID-19) pandemic. Methods We searched 6 databases (PubMed, Embase, SPORTDiscus, Scopus, Web of Science, and CINAHL) in April 2024. Medical subject headings and keywords related to PA and COVID-19 were combined to conduct the online search, which covered the period from July 2020 to April 2024. Results Overall, 49,579 articles were retrieved. After duplicate removal and title, abstract, and full-text screening, 1,976 articles were included in this update. Most of the studies were observational with a cross-sectional design (68.0%). Most of COVID-19 and PA studies came from high-income countries. Most studies explored the changes in PA levels due to the COVID-19 pandemic and its effects on mental health outcomes. Conclusion Research on PA and COVID-19 prioritized online approach and cross-sectional designs. Most of the evidence identified a decrease in PA levels due to social distancing measures.

Selective fluorination of the pyrrolidine ring in proline motifs has been found to induce significant conformational changes that impact the structure and biological roles of modified peptides and proteins. Vicinal difluorination of fluoroproline, for example, in (3S,4R)-3,4-difluoroproline, serves to mitigate the inherent conformational bias of the pyrrolidine ring by inducing stereoelectronic effects that attenuate this conformational bias. In this investigation, we present a quantumchemical analysis of the conformational equilibrium and effects that are induced in difluorinated pyrrolidines, with a particular focus on exploring the impact of gauche and anomeric effects on the conformer stabilities of different stereo- and regioisomers. Initially, we conducted a benchmark assessment comparing the optimal density functional theory method with coupled cluster with single and double excitations (CCSD) calculations and crystallographic data using the 3-fluoropyrrolidinium cation and 3-fluoropyrrolidine. Subsequently, we explored the relative energy of all favored conformations of all different stereoisomers of 2,3-, 2,4-, and 3,4-difluoropyrrolidines at the B3LYP-D3BJ/6-311++G** level. A generalized anomeric effect, arising from nN→σ*CF electron delocalization, is particularly important in modulating the energetics of the α-fluoro isomers and imparts a strong conformational bias. In contrast, the fluorine gauche effect assumes a secondary role, as it is overshadowed by steric and electrostatic interactions, referred to as Lewis interactions from a natural bond orbital perspective.

Molecular polarity governs lipophilicity, which in turn determines important agrochemical and environmental properties, such as soil sorption and bioconcentration of organic compounds. Since the C–F bond is the most polar in organic chemistry, the orientation of fluorine substituents originating from the rotation around C–C(F) bonds should affect the polarity and, consequently, the physicochemical and biological properties of fluorine-containing agrochemicals. Accordingly, this study aims to determine the most likely conformers of some fluorine-containing agrochemicals and to correlate their molecular dipole moments with the respective n-octanol/water partition coefficients (log P), in order to investigate the dependence of the lipophilicity with the molecular conformation.

The active species of the Ishikawa´s reagent [N,N-diethyl-(1,1,2,3,3,3-hexafluoropropyl)amine] is a fluorinating hexafluoropropylamine used to convert alcohols into alkyl fluorides. On the other hand, it is also an example of model compound useful to probe conformational preferences using spectroscopic information from diastereotopic fluorines. Moreover, the possibility of experiencing both the generalized anomeric and gauche effects makes the Ishikawa´s reagent an ideal choice to study the governing stereoelectronic interactions of the conformational equilibrium of organofluorine compounds. The conformational equilibrium of the Ishikawa´s reagent was analyzed using NMR 3JH,F coupling constant data in different solvents, since the orientation of the diastereotopic fluorines relative to H-2 and F-2 changes with the medium. In nonpolar cyclohexane solvent, the preferred conformation experiences a weaker steric and electrostatic repulsion. The conformational behavior changes in the more polar pyridine solution, where the double fluorine gauche effect takes place, since F-2 is preferably gauche to both diastereotopic fluorines. An analysis of the rotation around the N–C(F2) bond indicates the manifestation of anomeric interactions (nN → σ*C–F), which can be demonstrated by means of 19F chemical shifts. The results were rationalized with the aid of theoretical calculations and natural bond orbital (NBO) analysis, allowing for the evaluation of competing steric, electrostatic and hyperconjugative interactions.

2-Haloketones are building blocks that combine physical, chemical and biological features of materials and bioactive compounds, while organic fluorine plays a fundamental role in the design of performance organic molecules. Since these features are dependent on the three-dimensional chemical structure of a molecule, simple structural modifications can affect its conformational stability and, consequently, the corresponding physicochemical/biological property of interest. In this work, structural changes in 2-fluorocyclohexanone were theoretically studied with the aim at finding intramolecular interactions that induce the conformational equilibrium towards the axial or equatorial conformer. The interactions evaluated were hydrogen bonding, hyperconjugation, electrostatic and steric effects. While the gauche effect, originated from hyperconjugative interactions, does not appear to cause some preferences for the axial conformation of organofluorine heterocycles, more classical effects indeed rule the conformational equilibrium of the compounds. Spectroscopic parameters (NMR chemical shifts and coupling constants), which can be useful to determine the stereochemistry and the interactions operating in the series of 2-fluorocyclohexanone derivatives, were also calculated.

An intriguing question in 3D-QSAR lies on which conformation(s) to use when generating molecular descriptors (MD) for correlation with bioactivity values. This is not a simple task because the bioactive conformation in molecule data sets is usually unknown and, therefore, optimized structures in a receptor-free environment are often used to generate the MD´s. In this case, a wrong conformational choice can cause misinterpretation of the QSAR model. The present computational work reports the conformational analysis of the volatile anesthetic isoflurane (2-chloro-2-(difluoromethoxy)-1,1,1-trifluoroethane) in the gas phase and also in polar and nonpolar implicit and explicit solvents to show that stable minima (ruled by intramolecular interactions) do not necessarily coincide with the bioconformation (ruled by enzyme induced fit). Consequently, a QSAR model based on two-dimensional chemical structures was built and exhibited satisfactory modeling/prediction capability and interpretability, then suggesting that these 2D MD´s can be advantageous over some three-dimensional descriptors.

The use of herbicides has been carried out without considering the physical and chemical properties of the soil and its variation in the different producing regions. Its interaction is dependent on the properties of the soil and the herbicide itself and, therefore, is considered complex. An alternative to optimize the use of herbicides is the application of mathematical models to estimate the sorption in the soil, contributing to a more efficient control of weeds and bringing more environmental safety. In this study, the efficiency of Artificial Neural Networks (ANNs) was evaluated as a tool to predict clomazone sorption in different Brazilian soils. The herbicide sorption coefficients were determined in the laboratory with 45 soils from different soil environments. Multilayer perceptron (MLP) ANN models were used to predict clomazone sorption. The variables were selected using the feature selection tool using the physical and chemical properties of the soils. Multivariate statistics were performed to determine the correlations between the physical and chemical properties of the soil with the sorption coefficient. Potassium (K), phosphorus (P), magnesium (Mg), organic matter (OM), silt, clay, and cation exchange capacity (CEC) were the ANN inputs and the sorption coefficient (Kfs) the output. The general performance of the model was evaluated by its precision and error values, namely: coefficient of determination (R2), mean absolute relative error (RMSE), mean absolute error (MAE), mean estimation error (MBE), and the coefficient Pearson correlation test (r). The ANN models were able to predict the Kfs of clomazone in the studied soils. The input variables that determined the best performing network for Kfs prediction were: CTC, Silt, Mg, and K. The variables that showed greater relative importance in the sensitivity analysis in the construction of the model for the Kfs of clomazone were: K (37 %) and Silt (29 %). The best RNA model was able to recommend reducing the dose of clomazone compared to the commercial package insert method.

The management of weeds in melon is hindered by the slow initial growth of the crop, favouring weed infestation and reducing production. During the years 2016 and 2017, weed interference periods were evaluated in two melon hybrids, yellow and frog skin, to determine the time of weed control in the crop. Four-parameter logistic regression was used to determine the critical weed control period (CPWC). The weed species with the highest occurrences in 2016 were Merremia aegyptia, Senna obtusifolia, and Urochloa plantaginea. In 2017, there was a predominance of M. aegyptia, indicating the possibility of successive cultivation, favouring the predominance of species with growth habits similar to melons. The increase in the period of living with weeds reduced the productivity and quality of melon fruits. Coexistence with weeds throughout the cycle reduced productivity by about 50%. The CPWC was 15 to 58 and 10 to 45 for frog skin and 12 to 52 and 4 to 50 days for yellow melon in 2016 and 2017, respectively, considering a productivity loss of 5%. These results underscore the importance of adopting strategies that allow melons to grow free from the presence of weeds, especially before they are fully established in the growing area.

Abstract The objective of this work was to evaluate the effectiveness and selectivity of herbicides applied at preemergence to the melon (Cucumis melo) crop. The experiments were carried out from 2017 to 2018, in a randomized complete block design, with four replicates, in the state of Rio Grande do Norte, Brazil. The treatments consisted of the preemergence application of: 35 g ha-1 a.i. flumioxazin, 25 g ha-1 a.i. flumioxazin, 250 g ha-1 a.i. sulfentrazone, 480 g ha-1 a.i. metribuzin, 240 g ha-1 a.i. oxyfluorfen, 240 g ha-1 a.i. oxyfluorfen + 960 g ha-1 a.i. S-metolachlor, 360 g ha-1 a.i. clomazone, and 360 g ha-1 a.i. clomazone + 240 g ha-1 a.i. oxyfluorfen; in 2018, metribuzin did not show selectivity and was substituted by 480 g ha-1 a.i. ametryn and 1,600 g ha-1 a.i. diuron. Fruit yield and quality, as well as weed control and dry mass, were evaluated. The metribuzin, ametryn, and diuron herbicides caused melon plant death. The best efficiency in weed control was obtained with the mixture clomazone + oxyfluorfen, followed by oxyfluorfen, oxyfluorfen + S-metolachlor, and clomazone. The treatments with oxyfluorfen, oxyfluorfen + S-metolachlor, and clomazone + oxyfluorfen were not considered selective. Clomazone was the only selective herbicide in the two years of evaluation and can be an alternative for weed control in melon crops.

O estudo buscou identificar o nível de conhecimento sobre treinamento resistido (TR) e sua relação com a prática dessa modalidade em alunos dos anos iniciais e finais dos cursos de bacharelado e licenciatura em Educação Física de uma universidade no sul do Brasil. A amostra era composta por universitários de ambos os sexos (n=170), divididos em quatro grupos: alunos do primeiro e último ano dos cursos de bacharelado e licenciatura (diurno/noturno). Assim, foi utilizado um questionário composto por 30 questões fechadas, que propunha identificar o nível de conhecimento sobre TR. O instrumento era dividido em dois domínios (15 questões cada): anatomia-cinesiologia e princípios-métodos. O escore máximo possível era de 30 pontos (15 pontos por domínio), e para que fosse considerado como satisfatório, o escore deveria atingir o ponto de corte de 70% do escore máximo. Entre os alunos que praticavam TR, foi observada prevalência de prática superior a um ano (43,3%). Ainda, os estudantes do último ano dos cursos de licenciatura e bacharelado apresentaram escore total médio de 17,9 e 18,8 pontos (p>0,05). Todavia, os alunos ingressantes obtiveram escores total médio estatisticamente menores (10,6 e 13,5 anos, respectivamente; p0,05). Nevertheless, first year undergraduate students achieved mean total score statistically different when compared with last year students (10.6 and 13.5, respectively; p

O conhecimento dos profissionais de Educação Física (EF) que atuam nas academias na modalidade de treinamento resistido (TR) é de extrema importância, para que os objetivos dos indivíduos praticantes sejam alcançados de modo eficiente e com riscos diminuídos para lesões advinda da prática. Todavia, há uma escassez de instrumentos validados para medir conhecimento em TR. Assim, o presente estudo objetivou validar um questionário sobre conhecimento de acadêmicos do curso de EF sobre TR. A amostra foi composta por 59 estudantes do curso de EF de uma universidade situada na cidade de Pelotas/RS. Os alunos tinham idade média igual a 24,3 ± 5,7 anos, sendo a maioria (59%) do sexo masculino. O instrumento utilizado foi criado pelos autores e era composto por 30 questões de múltipla escolha. O questionário era dividido em dois domínios (15 questões cada): anatomia-cinesiologia e princípios-métodos do TR. Os resultados mostraram que os escores obtidos na primeira e segunda coleta apresentaram reprodutibilidade moderada quando analisado o escore total (r= 0,80; Lin= 0,66; p

The global rise of infectious disease outbreaks and the progression of microbial resistance reinforce the importance of researching new biomolecules. Obtained from the hydrolysis of chitosan, chitooligosaccharides (COSs) have demonstrated several biological properties, including antimicrobial, and greater advantage over chitosan due to their higher solubility and lower viscosity. Despite the evidence of the biotechnological potential of COSs, their effects on trypanosomatids are still scarce. The objectives of this study were the enzymatic production, characterization, and in vitro evaluation of the cytotoxic, antibacterial, antifungal, and antiparasitic effects of COSs. NMR and mass spectrometry analyses indicated the presence of a mixture with 81% deacetylated COS and acetylated hexamers. COSs demonstrated no evidence of cytotoxicity upon 2 mg/mL. In addition, COSs showed interesting activity against bacteria and yeasts and a time-dependent parasitic inhibition. Scanning electron microscopy images indicated a parasite aggregation ability of COSs. Thus, the broad biological effect of COSs makes them a promising molecule for the biomedical industry.

This study assesses the efficacy of different nanoemulsion formulations as new and innovative adjuvants for improving the in vivo immunization against the Tityus serrulatus scorpion venom. Nanoemulsions were designed testing key-variables such as surfactants, co-solvents, and the influence of the temperature, which would be able to induce the phase transition from a liquid crystal to a stable nanoemulsion, assessed for four months. Additionally, cationic-covered nanoemulsion with hyper-branched poly(ethyleneimine) was prepared and its performance was compared to the non-cationic ones. The physicochemical properties of the selected nanoemulsions and the interactions among their involved formulation compounds were carefully monitored. The cytotoxicity studies in murine macrophages (RAW 264.7) and red blood cells were used to compare different formulations. Moreover, the performance of the nanoemulsion systems as biocompatible adjuvants was evaluated using mice immunization protocol. The FTIR shifts and the zeta potential changes (from −18.3 ± 1.0 to + 8.4 ± 1.4) corroborated with the expected supramolecular anchoring of venom proteins on the surface of the nanoemulsion droplets. Cell culture assays demonstrated the non-toxicity of the formulations at concentrations less than 1.0 mg/mL, which were able to inhibit the hemolytic effect of the scorpion venom. The cationic-covered nanoemulsion has shown superior adjuvant activity, revealing the highest IgG titer in the immunized animals compared to both the non-cationic counterpart and the traditional aluminum adjuvant. In this approach, we demonstrate the incredible potential application of nanoemulsions as adjuvants, using a nanotechnology platform for antigen delivery system on immune cells. Additionally, the functionalization with hyper-branched poly(ethyleneimine) enhances this recognition and improves its action in immunization.

Chitosan films entrapped with the Mansoa hirsuta fraction (CMHF) was developed as a new dressing for wound care. The chromatographic profile of the M. hirsuta fraction (MHF) was evaluated by ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry, and the results showed that MHF is rich in acid triterpenes. Physicochemical characterization of the films prepared using the solvent casting method was performed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetry (TGA), differential scanning calorimetry (DCS), scanning electron microscopy (SEM), atomic force microscopy (AFM), and mechanical properties. CMHF exhibited characteristic bands of both chitosan and MHF, revealing a physical mixture of both. CMHF presented an amorphous nature, thermostability, and dispersion of MHF in the chitosan matrix, resulting in a rough structure. Incorporation of M. hirsuta fraction into chitosan matrix favorably enhanced the mechanical performance and films thickness. The in vivo wound treatment with CMHF for seven days showed a characteristic area of advanced healing, re-epithelization, cell proliferation, and collagen formation. Furthermore, wound closure reached 100% contraction after 10 days of treatment with modulation of interleukins. The incorporation of M. hirsuta fraction into chitosan films was advantageous and showed great potential for stimulating wound repair and regeneration.

Objetivou-se verificar o impacto da intervenção “Educação Física+: Praticando Saúde na Escola”, sobre as práticas docentes e conhecimento em saúde de escolares da cidade de Canguçu/RS. Quinze escolas participaram do estudo (grupo 1- escolas que aderiram à intervenção no ano de 2011; grupo 2- escolas que aderiam à intervenção a partir do ano de 2012). O estudo teve duração de oito meses com 624 escolares e 12 professores. Houve aumento do nível de conhecimento dos escolares no pós-intervenção (p

Chloroquine diphosphate (CQ) is a hydrophilic drug with low entrapment efficiency in hydrophobic nanoparticles (NP). Herpes simplex virus type 1 (HSV-1) is an enveloped double-stranded DNA virus worldwide known as a common human pathogen. This study aims to develop chloroquine-loaded poly(lactic acid) (PLA) nanoparticles (CQ-NP) to improve the chloroquine anti- HSV-1 efficacy. CQ-NP were successfully prepared using a modified emulsification-solvent evaporation method. Physicochemical properties of the NP were monitored using dynamic light scattering, atomic force microscopy, drug loading efficiency, and drug release studies. Spherical nanoparticles were produced with modal diameter of −1 (p < 0.001). On the other hand, the B-NP had no antiviral activity. The CQ-NP has shown feasible properties and great potential to improve the antiviral activity of drugs.

In Brazil, envenomation by snakes of the genus Bothrops is clinically relevant, particularly for the species Bothrops jararaca and B. erythromelas. The most effective treatment for envenomation by snakes is the administration of antivenoms associated with adjuvants. Novel adjuvants are required to reduce side effects and maximize the efficiency of conventional serum and vaccine formulations. The polymer chitosan has been shown to have immunoadjuvant properties, and it has been used as a platform for delivery systems. In this context, we evaluated the potential immunoadjuvant properties of chitosan nanoparticles (CNPs) loaded with B. jararaca and B. erythromelas venoms in the production of sera against these venoms. Stable CNPs were obtained by ionic gelation, and mice were immunized subcutaneously for 6 weeks with 100 µL of each snake venom at concentrations of 5.0 or 10.0% (w/w), encapsulated in CNPs or associated with aluminium hydroxide (AH). The evaluation of protein interactions with the CNPs revealed their ability to induce antibody levels equivalent to those of AH, even with smaller doses of antigen. In addition, the CNPs were less inflammatory due to their modified release of proteins. CNPs provide a promising approach for peptide/protein delivery from snake venom and will be useful for new vaccines.