Mechanistic insights into C(sp2)-H activation in 1-Phenyl-4-vinyl-1H-1,2,3-triazole derivatives: a theoretical study with palladium acetate catalyst.

CONTEXT: The activation of C-H bonds is a fundamental process in synthetic organic chemistry, which enables their replacement by highly reactive functional groups. Coordination compounds serve as effective catalysts for this purpose, as they facilitate chemical transformations by interacting with C-H bonds. A comprehensive understanding of the mechanism of activation of this type of bond lays the foundation for the development of efficient protocols for cross-coupling reactions. We explored the activation of C(sp2)-H bonds in 1-Phenyl-4-vinyl-1H-1,2,3-triazole derivatives with CH3, OCH3, and NO2 substituents in the para position of the phenyl ring, using palladium acetate as catalyst. The studied reaction is the first step for subsequent conjugation of the triazoles with naphthoquinones in a Heck-type reaction to create a C-C bond. The basic nitrogen atoms of the 1,2,3-triazole coordinate preferentially with the cationic palladium center to form an activated species. A concerted proton transfer from the terminal vinyl carbon to one of the acetate ligands with low activation energy is the main step for the C(sp2)-H activation. This study offers significant mechanistic insights for enhancing the effectiveness of C(sp2)-H activation protocols in organic synthesis. METHODS: All calculations were performed using the Gaussian 09 software package and density functional theory (DFT). The structures of all reaction path components were fully optimized using the CAM-B3LYP functional with the Def2-SVP basis set. The optimized geometries were analyzed by computing the second-order Hessian matrix to confirm that the corresponding minimum or transition state was located. To account for solvent effects, the Polarizable Continuum Model of the Integral Equation Formalism (IEFPCM) with water as the solvent was used.

Structural and thermodynamic insights into the coordination preference of norbornadiene with the initiator complex [RuCl2(PPh3)2(piperidine)] in polymerization via olefin metathesis.

The metathesis reaction has been an important tool in both organic and inorganic synthetic chemistry. More specifically in polymer chemistry, ring opening metathesis polymerization (ROMP), via the formation of an active metal-carbene species (MCHR), has been widely used. The elucidation of the mechanism for ROMP opened the way for the development of well-defined catalysts, suited to local conditions. In the present study, we employed density functional theory (DFT) to investigate three reaction pathways for the formation of a species capable of activating ROMP. The active species is formed from the [RuCl2(PPh3)2(pip)] complex in the presence of norbornadiene (NBD) and the carbene source ethyl diazoacetate (EDA). Formation of a hexacoordinated intermediate [RuCl2(PPh3)2(pip)(NBD)] is favored in the first step, with NBD doubly coordinated to the [RuCl2(PPh3)2(pip)] moiety. Analysis of donation (X → Ru) and back-donation (Ru → X) processes in the [RuCl2(PPh3)2(pip)(NBD)] complex shows that piperidine behaves as a σ donor, while NBD behaves as a π donor and the PPh3 groups act as π acceptors. The intensity of the orbital component is predominant in relation to the steric component in the complex. Thus, we propose that the reaction occurs through the formation of a hexacoordinated complex, followed by the dissociation of a PPh3 group, thus forming a complex where NBD is doubly coordinated to the metal center. Coordination of EDA leads finally to the catalyst capable of forming the metallocyclobutane intermediate required for the ROMP reaction.

Density functional theory investigation of the contributions of π-π stacking and hydrogen bonding with water to the supramolecular aggregation interactions of model asphaltene heterocyclic compounds.

CONTEXT: A complex supramolecular process involving electrostatic and dispersion interactions and asphaltene aggregation is associated with detrimental petroleum deposition and scaling that pose challenges to petroleum recovery, transportation, and upgrading. The homodimers of seven heterocyclic model compounds, representative of moieties commonly found in asphaltene structures, were studied: pyridine, thiophene, furan, isoquinoline, pyrazine, thiazole, and 1,3-oxazole. The contributions of hydrogen bonding involving water bridges spanning between dimers and π-π stacking to the total interaction energy were calculated and analyzed. The distance between the planes of the aromatic rings is correlated with the π-π stacking interaction strength. All the dimerization reactions were exothermic, although not spontaneous. This was mostly modulated by the strength of the hydrogen bond of the water bridge and the π-π stacking interaction. Dimers bridged by two water molecules were more stable than those with additional water molecules or without any water molecule in the bridge. Energy decomposition analysis showed that the electrostatic and polarization components were the main stabilizing terms for the hydrogen bond interaction in the bridge, contributing at least 80% of the interaction energy in all dimers. The non-covalent interaction analysis confirmed the molecular sites that had the strongest (hydrogen bond) and weak (π-π stacking) attractive interactions. They were concentrated in the water bridge and in the plane between the aromatic rings, respectively. METHODS: The density functional ωB97X-D with a dispersion correction and the Def2-SVP basis set were employed to investigate supramolecular aggregates incorporating heterocycles dimers with 0, 1, 2, and 3 water molecules forming a stabilizing bridge connecting the monomers. The non-covalent interactions were analyzed using the NCIplot software and plotted as isosurface maps using Visual Molecular Dynamics.

Exploring borderline SN1-SN2 mechanisms: the role of explicit solvation protocols in the DFT investigation of isopropyl chloride.

Nucleophilic substitution at saturated carbon is a crucial class of organic reactions, playing a pivotal role in various chemical transformations that yield valuable compounds for society. Despite the well-established SN1 and SN2 mechanisms, secondary substrates, particularly in solvolysis reactions, often exhibit a borderline pathway. A molecular-level understanding of these processes is fundamental for developing more efficient chemical transformations. Typically, quantum-chemical simulations of the solvent medium combine explicit and implicit solvation methods. The configuration of explicit molecules can be defined through top-down approaches, such as Monte Carlo (MC) calculations for generating initial configurations, and bottom-up methods that involve user-dependent protocols to add solvent molecules around the substrate. Herein, we investigated the borderline mechanism of the hydrolysis of a secondary substrate, isopropyl chloride (iPrCl), at DFT-M06-2X/aug-cc-pVDZ level, employing explicit and explicit + implicit protocols. Top-down and bottom-up approaches were employed to generate substrate-solvent complexes of varying number (n = 1, 3, 5, 7, 9, and 12) and configurations of H2O molecules. Our findings consistently reveal that regardless of the solvation approach, the hydrolysis of iPrCl follows a loose-SN2-like mechanism with nucleophilic solvent assistance. Increasing the water cluster around the substrate in most cases led to reaction barriers of ΔH‡ ≈ 21 kcal mol-1, with nine water molecules from MC configurations sufficient to describe the reaction. The More O'Ferrall-Jencks plot demonstrates an SN1-like character for all transition state structures, showing a clear merged profile. The fragmentation activation strain analyses indicate that energy barriers are predominantly controlled by solvent-substrate interactions, supported by the leaving group stabilization assessed through CHELPG atomic charges.

Facial soft tissue changes and volumetric analysis of upper airways in patients undergoing surgically assisted rapid maxillary expansion using a transpalatal distractor.

OBJECTIVE: To verify changes in facial soft tissue using the RadiANT-DICOM-viewer and Dolphin Imaging software, through linear measurements of tomographic points in a 3D reconstruction of the face and volumetric evaluation with three-dimensional measurements of the upper airways of patients with transverse maxillary discrepancy undergoing Surgically Assisted Rapid Maxillary Expansion (SARME). METHODS: Retrospective, transverse, and descriptive study, through the analysis of computed tomography scans of the face of patients with transverse maxillary discrepancy, treated from July 2019 to December 2022. The sample consisted of 15 patients of both sexes, aged 21-42 years old, who underwent surgically assisted rapid maxillary expansion using the transpalatal distractor. Analysis was performed through linear, angular, and three-dimensional measurements in millimeters, in the preoperative and late four-month postoperative period, in frontal 3D tomographic images of the face, in the region of the width of the nose and alar base and also angular measurement in the lateral tomography for the angle nasolabial and upper airways of rhinopharynx, oropharynx and hypopharynx. RESULTS: There was an increase in nasal width with an average of 1.3467mm and an increase in the alar base with an average of 1.7333mm. A significant difference was found in the pre- and postoperative assessments of the measurements of nasal width, alar base and nasolabial angle, as well as the upper airways in all their extension. The results favour a better understanding of the professional and the patient regarding the diagnosis and management of patients with transverse maxillary width discrepancies. CONCLUSION: Although our study shows an increase in soft tissues after SARME, no aesthetic changes are observed clinically, and all patients report significant respiratory improvement. SARME may therefore contribute to the improvement of professionals working in the field of oral and maxillofacial surgery and orthodontics. LEVEL OF EVIDENCE: Level 4.

Tensile and Tearing Properties of a Geocomposite Mechanically Damaged by Repeated Loading and Abrasion.

The behaviour of geosynthetics can be affected by many agents, both in the short and long term. Mechanical damage caused by repeated loading or abrasion are examples of agents that may induce undesirable changes in the properties of geosynthetics. The research conducted in this work complemented previous studies and consisted of submitting a geocomposite, isolated and successively, to two degradation tests: mechanical damage under repeated loading and abrasion. The geocomposite (a nonwoven geotextile reinforced with polyethylene terephthalate filaments) was tested on both sides (with or without filaments) and directions (machine and cross-machine). The impact of the degradation tests on the geocomposite was quantified by monitoring changes in its tensile and tearing behaviour. The results showed that, in most cases, the degradation tests caused the deterioration of the tensile and tearing behaviour of the geocomposite, affecting its reinforcement function. The decline in tensile strength correlated reasonably well with the decline in tearing strength. Changing the side and direction tested influenced, in some cases (those involving abrasion), the degradation experienced by the geocomposite. The reduction factors (referring to tensile and tearing strength) for the combined effect of the degradation agents tended to be lower when determined by using the common method (compared to those resulting directly from the successive exposure to both agents).

Parâmetros espirométricos podem predizer a incidência de fragilidade em pessoas idosas? / Can spirometric parameters predict the incidence of frailty in the elderly people?

Objetivo: Verificar a associação entre indicadores espirométricos e a incidência da síndrome de fragilidade em pessoas idosas. Métodos: Trata-se de um estudo com delineamento longitudinal realizado em 2014-2019, com uma amostra de estudo de 104 pessoas idosas. A variável dependente foi a síndrome de fragilidade, avaliada por meio do fenótipo de Fried et al. e as variáveis independentes foram os indicadores espirométricos, sendo eles a Capacidade Vital Forçada (CVF), Pico de Fluxo Expiratório (PFE), Volume Expiratório Forçado no primeiro segundo (VEF1), relação VEF1/CVF e o Fluxo Expiratório Forçado 25%-75% (FEF25-75%). Resultados: A incidência de pessoas idosas frágeis foi de 16,3% em ambos os sexos, sendo que o sexo masculino apresentou melhores indicadores de função pulmonar que as mulheres. Apesar disso, observamos que não houve associação entre a síndrome de fragilidade e os indicadores espirométricos (p>0,05). Conclusão: Os indicadores espirométricos não são preditores de fragilidade em pessoas idosas residentes na comunidade, após cinco anos de seguimento.

Objective: To verify the association between spirometric indicators and the incidence of frailty syndrome in elderly people. Methods: This is a study with a longitudinal design carried out in 2014-2019, with a study sample of 104 elderly people. The dependent variable was the frailty syndrome, assessed using the phenotype of Fried et al. and the independent variables were the spirometric indicators, namely Forced Vital Capacity (FVC), Peak Expiratory Flow (PEF), Forced Expiratory Volume in one second (FEV1), FEV1/FVC ratio and Forced Expiratory Flow 25%-75 % (FEF25-75%). Results: The incidence of frail elderly people was 16.3% in both genders, with males presenting better lung function indicators than females. Despite this, we observed that there was no association between the frailty syndrome and the spirometric indicators (p>0.05). Conclusion: Spirometric indicators are not predictors of frailty in community-dwelling elderly people after five years of follow-up.

A Case of Acute Eosinophilic Pneumonia Triggered by the SARS-CoV-2 Virus.

We report a case of acute eosinophilic pneumonia (AEP) triggered by the coronavirus disease 2019 (COVID-19) infection. A 60-year-old male with chronic sinusitis and tobacco use presented to the emergency department (ED) with an acute onset of dyspnea, non-productive cough, and fever. A diagnosis of moderate SARS-CoV-2 infection with bacterial superinfection was made. He was discharged on antibiotic therapy. One month later, due to the persistence of symptoms, he returned to the ED. At this time, blood analysis showed eosinophilia and a chest computed tomography scan showed bilateral diffuse infiltrative changes. He was admitted to the hospital for the study of eosinophilic disease. A lung biopsy was performed, which showed eosinophilic pneumonia. Corticotherapy was started with symptoms and peripheral eosinophilia resolution, and imaging improvement.

Analysis of Plantar Tactile Sensitivity in Older Women after Conventional Proprioceptive Training and Exergame.

OBJECTIVE: To evaluate and compare the effects of conventional proprioceptive training and games with motion monitoring on plantar tactile sensitivity in older women. METHODS: A randomized controlled clinical trial, with 50 older women randomized into three groups: conventional proprioception (n = 17), games with motion monitoring (n = 16), and the control (n = 17). They underwent 24 intervention sessions, three times a week, for eight weeks. The conventional proprioception group performed exercises involving gait, balance, and proprioception. The games performed by the motion monitoring group included exercises using the Xbox Kinect One video game from Microsoft®. The evaluation of tactile pressure sensitivity was performed using Semmes-Weinstein monofilaments. Intragroup comparisons between the two paired samples were performed using paired Student's t-test or Wilcoxon test. Intergroup comparisons between the three independent samples were performed using the Kruskal-Wallis test and Dunn's post hoc test, with p ≤ 0.05. RESULTS: The older women submitted to conventional games with motion monitoring training and showed improvement in plantar tactile sensitivity in the right and left feet. When comparing the intergroup results, the two training modalities obtained an improvement in the plantar tactile sensitivity of the older women when compared to the control group. CONCLUSIONS: We conclude that both training modalities may favor the improvement of plantar tactile sensitivity in older women, with no significant differences between conventional and virtual training.

Factors associated with frailty syndrome in older adults with three- and four-criteria clustering.

This study aimed to identify the main clusters of diagnostic criteria pertaining to frailty syndrome as well as the factors associated with the occurrence of frailty without diagnostic criteria clusters and with clusters of three and four criteria. This is a cross-sectional study, carried out with 216 older adults. In order to determine the dependent variable, a combination of the following criteria for frailty syndrome diagnostic criteria was used: unintentional weight loss, exhaustion, muscle weakness, a low level of physical activity, and a slow gait speed. There were different clusters of Frailty Syndrome diagnostic criteria and were associated with Frailty with clustering of three criteria, age group ≥80 years and negative self-perception of health and Frailty with clustering of four criteria, age group ≥80 years and polypharmacy use. Age, self-perception of health, and polypharmacy can be assessed to target different intervention plans in the frail older adult population.

Synthetic Naphthoquinone Derivatives as Anticancer Agents in Ovarian Cancer: Cytotoxicity Assay and Investigation of Possible Biological Mechanisms Action.

In this study, eight naphthoquinone derivatives were synthesized in yields ranging from 52 to 96% using easy, fast, and low-cost methodologies. All naphthoquinone derivatives were screened for their in vitro anti-proliferative activities against OVCA A2780 cancer cell lines. Amongst all analysed compounds, derivatives 3-5 presented the most prominent cytotoxic potential. Naphthoquinones 3 and 4, bearing sulfur-containing groups, were identified as having high potential for ROS production, in particular the superoxide anion. Furthermore, 3 and 4 compounds caused a decrease in the cell population in G0/G1 and induced more than 90% of the cell population to apoptosis. Compound 5 did not act in any of these processes. Finally, compounds 3-5 were tested for their inhibitory ability against PI3K and MAPK. Compounds 3 and 4 do not inhibit the PI3K enzyme. On the other hand, the naphthoquinone-polyphenol 5 was only able to inhibit the percentage of cells expressing pERK.

Development of a dental digital data set for research in artificial intelligence: The importance of labeling performed by radiologists.

OBJECTIVE: The aim of this study was to present the development of a database (dataset) of panoramic radiographs. STUDY DESIGN: Three radiologists labeled an image set consisting of 936 panoramic radiographs. Labeling includes tooth numbering (including teeth present and missing) and annotation of dental conditions (e.g., caries, dental restoration, residual root, endodontic treatment, implant, fixed prosthesis, incisal wear). The annotation process was performed in a Picture Archive and Communication System software customized for the study purposes using a small bounding box to delimit the entire tooth and items for radiographic diagnosis and a large bounding box to simultaneously delimit the 2 dental arches (maxilla and mandible). A JSON file was generated for each annotation. RESULTS: The database encompassed 23,619 annotations; disagreement between radiologists occurred in 0.7% of the notes. CONCLUSIONS: This work aims to inform researchers about the importance of the labeling process, in addition to providing the scientific community with a bank of labeled images to implement artificial intelligence systems in clinical practice.

Weathering of a Nonwoven Polypropylene Geotextile: Field vs. Laboratory Exposure.

Like other plastic materials, geosynthetics can undergo changes in their properties due to weathering. These changes must be known and, if necessary, duly accounted for in the design phase. This work evaluates the resistance of a nonwoven polypropylene geotextile to weathering, both in the field (under natural degradation conditions) and in the laboratory (under accelerated degradation conditions). The damage experienced by the geotextile in the field weathering tests was evaluated by monitoring changes in its physical (mass per unit area and thickness), mechanical (tensile, tearing and puncture behaviour) and hydraulic (water permeability normal to the plane) properties. Microscopic damage was assessed by scanning electron microscopy. In the laboratory weathering tests, only the tensile behaviour of the geotextile was monitored. The results showed that all geotextile properties were affected by weathering. The mechanical strength of the geotextile decreased in the field weathering tests. Microscopic transverse cracks were found in the weathered polypropylene fibres, which may explain the reduction in mechanical strength. The accumulation of dirt on the nonwoven structure altered the physical and hydraulic properties of the geotextile. Comparing the field and laboratory weathering tests, the reduction in tensile strength found after 24 months outdoors (roughly 30%) was very similar to that observed after 4000 h in the laboratory. This relationship may not be valid for other geotextiles or other exposure locations.

Influence of the metal - support and metal - metal interactions on Pd nucleation and NO adsorption in a Pd4/γ-Al2O3 (110D) model.

The role played by the metal - support (MSI) and metal - metal (MMI) interactions on two important processes in controlling the catalyst performance - nucleation and molecular adsorption - has been investigated using density functional theory (DFT), by means of B3LYP functional, combined with localized molecular orbital energy decomposition analysis (LMOEDA), and natural bond orbital (NBO) calculations, with aid of a Pd4/γ-alumina (110D) model (Pd4/Al13O23H7). Our results indicate the occurrence of an electronic metal - support interaction (EMSI) which induces a most intense charge transfer in the Pd4 → γ-alumina backdonation direction, most expressive in Pd → Al, promoting an electronic redistribution within the units and attenuating the MMI. Nevertheless, the MSI/MMI synergistic effect seems to favor slightly the nucleation of a fifth palladium atom, leading to a distorted square pyramidal arrangement for Pd5. The LMOEDA analysis points to a mostly covalent character in the Pd - Al bonds, whereas the Pd - O bonds are mainly electrostatic in nature. The palladium atoms deposited on oxygen anions are the acid centers, where both NO molecule and an additional palladium atom anchor more strongly. In addition, the MSI/MMI effect, through the electronic and geometric contributions, drives the adsorption of the NO molecule to the mode which most favors the Pd → NO (4dz2 → 2π*) backdonation (bridge mode). MSI and MMI effects on the nature of the Pd - O (electrostatic) and Pd - Al (covalent) bonds, charge transfer into Pd4/γ-Al2O3 (110D) interface (back donation) and preferential site for adsorption of a single NO molecule and an additional Pd atom (Pd - O).

Pressão expiratória máxima é boa preditora de incidência da síndrome de fragilidade em homens idosos / Maximum expiratory pressure is a good predictor of the incidence of the frailty syndrome in elderly men

Resumo O objetivo deste artigo é investigar a associação entre a Pressão Inspiratória Máxima (PImáx) e Pressão Expiratória Máxima (PEmáx) com a incidência da síndrome de fragilidade (SF), além de testar a capacidade preditiva da PImáx e PEmáx em discriminar a SF em idosos, de acordo com o sexo. Estudo longitudinal com cinco anos de seguimento (2014-2019), realizado com 104 idosos cadastrados na Estratégia Saúde da Família de um município da Bahia. A incidência da síndrome de fragilidade foi diagnosticada de acordo os critérios propostos por Fried et al., utilizando dados de 2019, após cinco anos de seguimento. A PImáx e PEmáx foram avaliadas conforme recomendações da Sociedade Brasileira de Pneumologia e Tisiologia em 2014 (linha de base). A incidência total da SF foi de 16,3% (IC95%: 9,2-23,6), sendo 13,6% (IC95%: 4,56-22,55) no sexo feminino e 20,0% (IC95%: 7,85-32,15) no sexo masculino. Os valores médios da PImáx e PEmáx foram, respectivamente, 60,8±21,2 cmH2O e 76,7±23,1 cmH2O no sexo feminino, e 79,5±27,0 cmH2Oe 114,7±29,8 cmH2O no sexo masculino. A SF esteve associada à PEmáx em idosos do sexo masculino (RR ajustado: 0,96; IC95%: 0,95-0,98; p-valor: 0,002), indicando que o aumento de 1 cmH2O da PEmáx reduz em 4% o risco de desenvolver a síndrome de fragilidade.

Abstract This article aims to investigate the association between maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) with the incidence of frailty syndrome (FS), in addition to testing the predictive ability of MIP and MEP to discriminate FS in elderly adults, according to sex. It is a longitudinal study with a five-year follow-up period (2014-2019), carried out with 104 elderly adults registered in the Family Health Strategy of a municipality in Bahia. The incidence of frailty syndrome was diagnosed according to criteria proposed by Fried et al., using data from 2019, after a five-year follow-up. The MIP and MEP were evaluated according to the recommendations of the Brazilian Society of Pulmonology and Phthisiology data in 2014 (baseline data). The total incidence of frailty syndrome was 16.3% (95%CI: 9.2-23.6), with 13.6% (95%CI: 4.56-22.55) in women and 20% (95%CI: 7.85-32.15) in men. The mean values of MIP and MEP were, respectively, 60,8±21,2 cmH2O and 76,7±23,1 cmH2O in women, and 79,5±27,0 cmH2O and 114,7±29,8 cmH2O in men. The frailty syndrome was associated with MEP in elderly adult men (adjusted RR: 0.96; 95%CI: 0.95-0.98; P-value: 0.002), indicating that the increase of 1cmH2O in MEP reduces by 4% the risk of developing the syndrome.

Theoretical study of keto-enol tautomerism in 7-epi-clusianone by quantum chemical calculations of NMR chemical shifts.

Plants from the Garcinia genus have been used worldwide due to their therapeutic properties. Among the various metabolites isolated from this genus, 7-epi-clusianone, a tetraprenylated benzophenone, stands out for its wide range of identified biological activities. This benzophenone can exist in five tautomeric forms, although the benzene-d6 and chloroform-d3 solution nuclear magnetic resonance (NMR) spectra revealed only two tautomeric forms (B and C) in equilibrium, with concentration ratio depending on the solvent in which the spectrum was obtained. Calculated energy values suggested that tautomeric forms B and E would be prevalent in benzene-d6 solution, in contrast to the experimental data. Considering this conflicting result, we employed the statistical DP4 + method based on 13C and 1H NMR chemical shift calculations, in the gas phase and in benzene-d6 solution, to confirm that the B and C tautomeric forms of 7-epi-clusianone are the most prevalent in the experimental conditions.

Synthesis, characterization, and thermal and computational investigations of the L-histidine bis(fluoride) crystal.

Nonlinear optical materials have been investigated recently due to their potential technological applications in information storage and communications. In this context, semi-organic crystals can effectively combine the desired nonlinear optical properties of amino acids with the promising mechanical and thermal properties of inorganic materials. In this work, we have synthesized and characterized a semi-organic crystal of the amino acid L-histidine and hydrofluoric acid and investigated the chemical interactions between the organic and inorganic moieties. The crystal of L-histidine bis(fluoride) has been produced by slow solvent evaporation and characterized by X-ray diffraction (XRD) crystallography and thermogravimetric and differential thermal analyses. The XRD conducted using the Rietveld method shows that the unit cell is orthorhombic with the P21212 space group and contains four L-histidine bis(fluoride) units. Both differential thermal analysis and temperature-dependent XRD show that the crystals are thermally stable up to 191°C and do not undergo phase transition. The computational Hirshfeld surface analysis of the crystal structure reveals the main intermolecular interactions. Density functional theory has been employed to calculate the ionic interaction energy and electrostatic potential maps and confirm the spontaneity of ionic association at 191°C. The combined experimental and computational results show that the thermal stability of the semi-organic L-histidine bis(fluoride) crystal makes it suitable for nonlinear optical applications in optical sensing and communication systems.

[Maximum expiratory pressure is a good predictor of the incidence of the frailty syndrome in elderly men]. / Pressão expiratória máxima é boa preditora de incidência da síndrome de fragilidade em homens idosos.

This article aims to investigate the association between maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) with the incidence of frailty syndrome (FS), in addition to testing the predictive ability of MIP and MEP to discriminate FS in elderly adults, according to sex. It is a longitudinal study with a five-year follow-up period (2014-2019), carried out with 104 elderly adults registered in the Family Health Strategy of a municipality in Bahia. The incidence of frailty syndrome was diagnosed according to criteria proposed by Fried et al., using data from 2019, after a five-year follow-up. The MIP and MEP were evaluated according to the recommendations of the Brazilian Society of Pulmonology and Phthisiology data in 2014 (baseline data). The total incidence of frailty syndrome was 16.3% (95%CI: 9.2-23.6), with 13.6% (95%CI: 4.56-22.55) in women and 20% (95%CI: 7.85-32.15) in men. The mean values of MIP and MEP were, respectively, 60,8±21,2 cmH2O and 76,7±23,1 cmH2O in women, and 79,5±27,0 cmH2O and 114,7±29,8 cmH2O in men. The frailty syndrome was associated with MEP in elderly adult men (adjusted RR: 0.96; 95%CI: 0.95-0.98; P-value: 0.002), indicating that the increase of 1cmH2O in MEP reduces by 4% the risk of developing the syndrome.

O objetivo deste artigo é investigar a associação entre a Pressão Inspiratória Máxima (PImáx) e Pressão Expiratória Máxima (PEmáx) com a incidência da síndrome de fragilidade (SF), além de testar a capacidade preditiva da PImáx e PEmáx em discriminar a SF em idosos, de acordo com o sexo. Estudo longitudinal com cinco anos de seguimento (2014-2019), realizado com 104 idosos cadastrados na Estratégia Saúde da Família de um município da Bahia. A incidência da síndrome de fragilidade foi diagnosticada de acordo os critérios propostos por Fried et al., utilizando dados de 2019, após cinco anos de seguimento. A PImáx e PEmáx foram avaliadas conforme recomendações da Sociedade Brasileira de Pneumologia e Tisiologia em 2014 (linha de base). A incidência total da SF foi de 16,3% (IC95%: 9,2-23,6), sendo 13,6% (IC95%: 4,56-22,55) no sexo feminino e 20,0% (IC95%: 7,85-32,15) no sexo masculino. Os valores médios da PImáx e PEmáx foram, respectivamente, 60,8±21,2 cmH2O e 76,7±23,1 cmH2O no sexo feminino, e 79,5±27,0 cmH2Oe 114,7±29,8 cmH2O no sexo masculino. A SF esteve associada à PEmáx em idosos do sexo masculino (RR ajustado: 0,96; IC95%: 0,95-0,98; p-valor: 0,002), indicando que o aumento de 1 cmH2O da PEmáx reduz em 4% o risco de desenvolver a síndrome de fragilidade.

Are maximum respiratory pressures predictors of sarcopenia in the elderly?

OBJECTIVE: To compare maximum respiratory pressures and spirometric parameters among elderly individuals classified as having no sarcopenia, probable sarcopenia, and confirmed sarcopenia, and to test the ability of these variables to discriminate sarcopenia in a community-dwelling elderly population. METHODS: This was a cross-sectional study involving 221 elderly (≥ 60 years of age) individuals of both sexes. Sarcopenia was diagnosed in accordance with the new consensus of the European Working Group on Sarcopenia in Older People. Maximum respiratory pressures and spirometry parameters were assessed. RESULTS: The prevalences of probable sarcopenia and confirmed sarcopenia were 20.4% and 4.1%, respectively. Regardless of the sex, those with confirmed sarcopenia had significantly lower MEP than those with no sarcopenia and probable sarcopenia, whereas only males with confirmed sarcopenia presented with significantly lower MIP than did the other individuals. There was an inverse association of MIP and MEP with sarcopenia, indicating that the decrease by 1 cmH2O in these parameters increases the chance of sarcopenia by 8% and 7%, respectively. Spirometric parameters were not associated with sarcopenia. Cutoff points for MIP and MEP, respectively, were ≤ 46 cmH2O and ≤ 50 cmH2O for elderly women, whereas they were ≤ 63 cmH2O and ≤ 92 cmH2O for elderly men, and both were identified as predictors of sarcopenia (area under the ROC curve > 0.70). CONCLUSIONS: Sarcopenia was associated with lower maximum respiratory pressures, but not with spirometric parameters. Maximum respiratory pressures can be used as markers of sarcopenia in a community-dwelling elderly population regardless of the sex.

2,5-Diketopiperazines via Intramolecular N-Alkylation of Ugi Adducts: A Contribution to the Synthesis, Density Functional Theory Study, X-ray Characterization, and Potential Herbicide Application.

To investigate the herbicidal potential of 2,5-diketopiperazines (2,5-DKPs), we applied a known protocol to produce a series of 2,5-DKPs through intramolecular N-alkylation of Ugi adducts. However, the method was not successful for the cyclization of adducts presenting aromatic rings with some substituents at the ortho position. Results from DFT calculations showed that the presence of voluminous groups at the ortho position of a benzene ring results in destabilization of the transition structure. Lower activation enthalpies for the SN2-type cyclization of Ugi adducts were obtained when bromine, instead of a chlorine anion, is the leaving group, indicating that the activation enthalpy for the cyclization step controls the formation of the 2,5-DKP. Some Ugi adducts and 2,5-DKPs formed crystals with suitable qualities for single-crystal X-ray diffraction data collection. Phytotoxic damage of some 2,5-DKPs on leaves of the weed Euphorbia heterophylla did not differ from those caused by the commercial herbicide diquat.