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1.
Sci Immunol ; 9(96): eadn3954, 2024 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-38848342

RESUMO

During ontogeny, γδ T cells emerge from the thymus and directly seed peripheral tissues for in situ immunity. However, their functional role in humans has largely been defined from blood. Here, we analyzed the phenotype, transcriptome, function, and repertoire of human γδ T cells in blood and mucosal and lymphoid tissues from 176 donors across the life span, revealing distinct profiles in children compared with adults. In early life, clonally diverse Vδ1 subsets predominate across blood and tissues, comprising naïve and differentiated effector and tissue repair functions, whereas cytolytic Vδ2 subsets populate blood, spleen, and lungs. With age, Vδ1 and Vδ2 subsets exhibit clonal expansions and elevated cytolytic signatures, which are disseminated across sites. In adults, Vδ2 cells predominate in blood, whereas Vδ1 cells are enriched across tissues and express residency profiles. Thus, antigenic exposures over childhood drive the functional evolution and tissue compartmentalization of γδ T cells, leading to age-dependent roles in immunity.


Assuntos
Receptores de Antígenos de Linfócitos T gama-delta , Humanos , Criança , Receptores de Antígenos de Linfócitos T gama-delta/imunologia , Adulto , Pré-Escolar , Adolescente , Adulto Jovem , Feminino , Lactente , Masculino , Pessoa de Meia-Idade , Subpopulações de Linfócitos T/imunologia , Idoso , Recém-Nascido
2.
Polymers (Basel) ; 16(9)2024 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-38732662

RESUMO

The goal of the study was to compare the surface characteristics of typical implant materials used in orthopedic surgery and traumatology, as these determine their successful biointegration. The morphological and chemical structure of Vortex plate anodized titanium from commercially pure (CP) Grade 2 Titanium (Ti2) is generally used in the following; non-cemented total hip replacement (THR) stem and cup Ti alloy (Ti6Al4V) with titanium plasma spray (TPS) coating; cemented THR stem Stainless steel (SS); total knee replacement (TKR) femoral component CoCrMo alloy (CoCr); cemented acetabular component from highly cross-linked ultrahigh molecular weight polyethylene (HXL); and cementless acetabular liner from ultrahigh molecular weight polyethylene (UHMWPE) (Sanatmetal, Ltd., Eger, Hungary) discs, all of which were examined. Visualization and elemental analysis were carried out by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). Surface roughness was determined by atomic force microscopy (AFM) and profilometry. TPS Ti presented the highest Ra value (25 ± 2 µm), followed by CoCr (535 ± 19 nm), Ti2 (227 ± 15 nm) and SS (170 ± 11 nm). The roughness measured in the HXL and UHMWPE surfaces was in the same range, 147 ± 13 nm and 144 ± 15 nm, respectively. EDS confirmed typical elements regarding the investigated prosthesis materials. XPS results supported the EDS results and revealed a high % of Ti4+ on Ti2 and TPS surfaces. The results indicate that the surfaces of prosthesis materials have significantly different features, and a detailed characterization is needed to successfully apply them in orthopedic surgery and traumatology.

3.
Sci Rep ; 14(1): 10200, 2024 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-38702397

RESUMO

Today, antibiotic therapies that previously worked well against certain bacteria due to their natural sensitivity, are becoming less effective. Honey has been proven to inhibit the biofilm formation of some respiratory bacteria, however few data are available on how the storage time affects the antibacterial effect. The activity of black locust, goldenrod, linden and sunflower honeys from three consecutive years (2020, 2021, 2022) was analyzed in 2022 against Gram-negative (Haemophilus influenzae, H. parainfluenzae, Pseudomonas aeruginosa) and Gram-positive (Streptococcus pneumoniae) bacteria using in vitro microbiological methods. After determining the physicochemical parameters of honey, broth microdilution was applied to determine the minimum inhibitory concentration of each honey type against each bacterium, and crystal violet assay was used to test their antibiofilm effect. The possible mechanism of action was explored with membrane degradation test, while structural changes were illustrated with scanning electron microscopy. Honeys stored for one or two years were darker than fresh honeys, while older honeys had significantly lower antibacterial activity. The most remarkable inhibitory effect was exerted by linden and sunflower honeys, and P. aeruginosa proved to be the most resistant bacterium. Based on our results, honey intended for medicinal purposes should be used as fresh as possible during a treatment.


Assuntos
Antibacterianos , Mel , Testes de Sensibilidade Microbiana , Mel/análise , Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Fatores de Tempo , Pseudomonas aeruginosa/efeitos dos fármacos , Armazenamento de Alimentos/métodos , Humanos
4.
Ambio ; 53(5): 664-677, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38441861

RESUMO

In recent decades, there has been a growing number of studies exploring the historical dimensions of the interconnectedness of human societies and the environment. A core approach in this field is historical ecology. We analyzed 544 historical-ecological papers to assess patterns and trends in the field. We found a high degree of interdisciplinarity with a focus on local case studies, of periods of fewer than 500 years, analyzing archival sources through quantitative approaches. The proportion of papers containing management recommendations has increased over time. To make historical ecology globally relevant, more effort should be made to utilize studies across languages, borders and worldviews. We call for high standards regarding the use of social scientific methodologies. Lastly, we argue that fostering longer-term studies and assessing the real-life impact of policy recommendations emerging from historical ecology can help the discipline better contribute solutions to the challenges facing humanity in an uncertain future.


Assuntos
Ecologia , Projetos de Pesquisa , Humanos , Incerteza
5.
Commun Biol ; 7(1): 323, 2024 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-38486083

RESUMO

Gene regulatory networks (GRNs) fulfill the essential function of maintaining the stability of cellular differentiation states by sustaining lineage-specific gene expression, while driving the progression of development. However, accounting for the relative stability of intermediate differentiation stages and their divergent trajectories remains a major challenge for models of developmental biology. Here, we develop an empirical data-based associative GRN model (AGRN) in which regulatory networks store multilineage stage-specific gene expression profiles as associative memory patterns. These networks are capable of responding to multiple instructive signals and, depending on signal timing and identity, can dynamically drive the differentiation of multipotent cells toward different cell state attractors. The AGRN dynamics can thus generate diverse lineage-committed cell populations in a robust yet flexible manner, providing an attractor-based explanation for signal-driven cell fate decisions during differentiation and offering a readily generalizable modelling tool that can be applied to a wide variety of cell specification systems.


Assuntos
Redes Reguladoras de Genes , Redes Neurais de Computação , Diferenciação Celular/genética
6.
Phys Chem Chem Phys ; 26(14): 10530-10537, 2024 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-38512242

RESUMO

The rate coefficient for two deuterium substituted isotopologues of reaction CH3 + HBr → CH4 + Br has been determined using the quasiclassical trajectory (QCT) method. We used the analytical potential energy surface (PES) fitted to high-level ab initio points in earlier work. The PES exhibits a pre-reaction van der Waals complex and a submerged potential barrier. The rate coefficients of the deuterated isotopologue reactions, similarly to the pure-protium isotopologue, show significant deviation from the Arrhenius law, namely, the activation energy is negative below about 600 K and positive above it: k[CH3 + DBr] = 1.35 × 10-11 exp(- 2472/T) + 5.85 × 10-13 exp(335/T) and k[CD3 + HBr] = 2.73 × 10-11 exp(- 2739/T) + 1.46 × 10-12 exp(363/T). The CH3 + DBr reaction is slower by a factor of 1.8, whereas CD3 + HBr isotopologue is faster by a factor of 1.4 compared to the HBr + CH3 system across a wide temperature range. The isotope effects are interpreted in terms of the properties of various regions of the PES. Quantum state-resolved simulations revealed that the reaction of CH3 with HBr becomes slower when any of the vibrational modes of the methyl radical is excited. This contradicts the assumption that vibrational excitation of methyl radicals enhances its reactivity, which is of historical importance: this assumption was used as an argument against the existence of negative activation energy in a decade-long controversy in the 1980s and 1990s.

7.
Neural Netw ; 173: 106204, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38412738

RESUMO

We explore element-wise convex combinations of two permutation-aligned neural network parameter vectors ΘA and ΘB of size d. We conduct extensive experiments by examining various distributions of such model combinations parametrized by elements of the hypercube [0,1]d and its vicinity. Our findings reveal that broad regions of the hypercube form surfaces of low loss values, indicating that the notion of linear mode connectivity extends to a more general phenomenon which we call mode combinability. We also make several novel observations regarding linear mode connectivity and model re-basin. We demonstrate a transitivity property: two models re-based to a common third model are also linear mode connected, and a robustness property: even with significant perturbations of the neuron matchings the resulting combinations continue to form a working model. Moreover, we analyze the functional and weight similarity of model combinations and show that such combinations are non-vacuous in the sense that there are significant functional differences between the resulting models.


Assuntos
Redes Neurais de Computação , Neurônios , Vias Neurais/fisiologia , Imageamento por Ressonância Magnética , Encéfalo
8.
Dent Mater ; 40(4): 581-592, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38368136

RESUMO

OBJECTIVE: The purpose was to evaluate the degree of conversion (DC), internal adaptation (IA) and closed porosity (CP) of short-fiber reinforced resin composites (SFRC) associated with layered or bulk restorative procedures in deep MOD cavities. METHODS: Eighty third molars with standardized MOD cavities (5-mm-depth, 2.5-mm-width) were randomly divided into four groups and restored as follows: 1) bulk SFRC; 2) layered SFRC; 3) flowable bulk-fill resin-based composites (RBC); 4) layered conventional RBC. After one-month wet storage the samples were subjected to micro-computed tomography measurements and scanning electron microscopy to assess the IA and CP. Micro-Raman spectroscopy was used to determine the DC in different depths. Data were subjected to ANOVA and Tukey's post-hoc test, multivariate analysis and partial eta-squared statistics (p < 0.05). Pearson correlation coefficient was determined to assess the relationship among the parameters of interest. RESULTS: Gap/total interface volume ratio ranged between 0.22-0.47%. RBCs applied in bulk revealed significantly lower gap volume (p < 0.001) and CP (p < 0.05). Each group showed complete detachment on the pulpal and partial on the lateral walls, except for group3. While the highest DC% was achieved by the conventional RBC (87.2%), followed by the flowable bulk-fill (81.2%), SFRC provided the best bottom to top DC ratio (bulk: 96.4%, layered: 98.7%). The effect of factors studied (RBC type, filling technique) on IA and DC was significant (p < 0.001). SIGNIFICANCE: Bulk placement of RBCs exhibited lower interfacial gap volume and achieved satisfactory DC without significant correlation between these parameters. Incremental insertion of SFRC had no advantage over bulk placement in terms of IA and DC.


Assuntos
Resinas Compostas , Materiais Dentários , Materiais Dentários/química , Microtomografia por Raio-X , Teste de Materiais , Polimerização , Propriedades de Superfície , Resinas Compostas/química
9.
Heliyon ; 10(3): e25271, 2024 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-38333814

RESUMO

Color etching is a useful corrosive process, widely applied in metallography to study the microstructure of metals. To prove the existence of the previously hypothesized steady-state etching rate, in-situ investigations were performed with spectroscopic ellipsometry during the color etching of ferritic materials. Kinetic information regarding the refractive index, extinction coefficient, and layer thickness were used to calculate the steady-state layer buildup rate, which was 1.90 ± 0.15 nm/s for low-carbon steel and 0.99 ± 0.06 nm/s for cast iron owing to its better corrosion resistance. The presented methodology and findings could help understanding other processes that involve the development of layers on metallic surfaces.

10.
bioRxiv ; 2024 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-38260588

RESUMO

The immune system comprises multiple cell lineages and heterogeneous subsets found in blood and tissues throughout the body. While human immune responses differ between sites and over age, the underlying sources of variation remain unclear as most studies are limited to peripheral blood. Here, we took a systems approach to comprehensively profile RNA and surface protein expression of over 1.25 million immune cells isolated from blood, lymphoid organs, and mucosal tissues of 24 organ donors aged 20-75 years. We applied a multimodal classifier to annotate the major immune cell lineages (T cells, B cells, innate lymphoid cells, and myeloid cells) and their corresponding subsets across the body, leveraging probabilistic modeling to define bases for immune variations across donors, tissue, and age. We identified dominant tissue-specific effects on immune cell composition and function across lineages for lymphoid sites, intestines, and blood-rich tissues. Age-associated effects were intrinsic to both lineage and site as manifested by macrophages in mucosal sites, B cells in lymphoid organs, and T and NK cells in blood-rich sites. Our results reveal tissue-specific signatures of immune homeostasis throughout the body and across different ages. This information provides a basis for defining the transcriptional underpinnings of immune variation and potential associations with disease-associated immune pathologies across the human lifespan.

11.
bioRxiv ; 2024 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-37461466

RESUMO

Single-cell RNA sequencing (scRNA-seq) is invaluable for profiling cellular heterogeneity and dissecting transcriptional states, but transcriptomic profiles do not always delineate subsets defined by surface proteins, as in cells of the immune system. Cellular Indexing of Transcriptomes and Epitopes (CITE-seq) enables simultaneous profiling of single-cell transcriptomes and surface proteomes; however, accurate cell type annotation requires a classifier that integrates multimodal data. Here, we describe MultiModal Classifier Hierarchy (MMoCHi), a marker-based approach for classification, reconciling gene and protein expression without reliance on reference atlases. We benchmark MMoCHi using sorted T lymphocyte subsets and annotate a cross-tissue human immune cell dataset. MMoCHi outperforms leading transcriptome-based classifiers and multimodal unsupervised clustering in its ability to identify immune cell subsets that are not readily resolved and to reveal novel subset markers. MMoCHi is designed for adaptability and can integrate annotation of cell types and developmental states across diverse lineages, samples, or modalities.

12.
BMC Plant Biol ; 23(1): 661, 2023 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-38124025

RESUMO

Encyclia is the second-largest genus in the neotropical subtribe Laeliinae (Orchidaceae) and has more than 150 species, which are characterized by fairly consistent flower morphology. Its taxonomy and species boundaries, however, seem to be still under debate. In the present study, we first examined the lip micromorphology of 61 species of Encyclia sensu stricto. We correlated our results with external flower morphology and phylogenetic analyses performed on a combined dataset that included both nuclear (ITS, Xdh, PhyC) and plastid markers (ycf1, rpl32, and trnL-trnF). Phylogenetic reconstruction showed that Encyclia sensu stricto species form a coherent, monophyletic group. However, it is difficult to determine the relationships between the different groups within one larger clade. The groups all form distinct lineages that evolved from a common ancestor. The UPGMA cluster analysis for the seven qualitative micromorphological features clearly divides the genus into two main groups, the larger of which is further subdivided into two subgroups. None of these, however, overlap with any of the phylogeographic units distinguished in previously published papers or in presented article. It is worth noting that the groups resulting from the UPGMA analysis cannot be defined by macromorphological features. The pattern of similarities between species, taking into account both macro- and micromorphological features, is eminently mosaic in nature, and only a multifaceted approach can explain this enigmatic group.


Assuntos
Orchidaceae , Filogenia , Orchidaceae/anatomia & histologia , Plastídeos/genética , Flores/genética
13.
Magy Onkol ; 67(4): 321-331, 2023 Dec 18.
Artigo em Húngaro | MEDLINE | ID: mdl-38109511

RESUMO

The appearance of hybrid imaging, including PET/CT has been a huge milestone not only in the development of nuclear medicine but of the whole medical imaging. The examination with 18F-FDG, the most frequently used radiopharmaceutical has become for now one of the most important diagnostic tools in oncological patient care, applied with numerous indication goals. However, the depiction of central nervous system malignancies, especially those of the brain, with FDG PET has limitations due to high cerebral background activity, it can be used primarily in lymphoma cases. To evaluate gliomas and brain metastases, amino acid tracers (11C-methionine, 18F-DOPA and 18F-FET) gained ground, which reflect other biological processes compared to that of FDG. Upon multiplying of evidences their usage is becoming more and more diverse, from the primary assessment of brain tumours (benign vs. malignant), through their grading and evaluation of posttherapeutical viability/recurrence, up to the radiotherapy planning. This paper reviews all of these in more details, mentioning shortly the prospects and challenges of the future.


Assuntos
Neoplasias Encefálicas , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Humanos , Fluordesoxiglucose F18 , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/patologia , Tomografia por Emissão de Pósitrons/métodos , Compostos Radiofarmacêuticos
14.
J Chem Phys ; 159(14)2023 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-37831719

RESUMO

We have developed the polyatomic extension of the established [M. Gustafsson, J. Chem. Phys. 138, 074308 (2013)] classical theory of radiative association in the absence of electronic transitions. The cross section and the emission spectrum of the process is calculated by a quasiclassical trajectory method combined with the classical Larmor formula which can provide the radiated power in collisions. We have also proposed a Monte Carlo scheme for efficient computation of ro-vibrationally quantum state resolved cross sections for radiative association. Besides the method development, the global potential energy and dipole surfaces for H + CN collisions have been calculated and fitted to test our polyatomic semiclassical method.

15.
Schizophr Res ; 261: 24-30, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37688910

RESUMO

Examining the heterogeneity of negative symptoms of schizophrenia contributes to the identification of available treatment targets. Generally, prior evidence classified three to four symptom treatment response trajectory groups over the course of positive symptoms, yet, no evidence exists regarding the heterogeneity of medium-term response to predominant negative symptoms. The current post-hoc analysis aims to identify the heterogeneity in negative symptom treatment response trajectories among patients with predominant negative symptoms who received either cariprazine or risperidone for 26 weeks. Treatment response was analyzed based on the: the Positive and Negative Syndrome Scale Factor Score for Negative Symptoms (PANSS-FSNS), and the Clinical Global Impression Severity (CGIS) and Improvement (CGII) scales. To identify subgroups of patients with a similar course of treatment response, group-based trajectory modelling was utilized. Results demonstrated that in comparison with competing models, a single trajectory best described the treatment response of patients with predominant negative symptoms. The results indicate that patients with predominant negative symptoms with over ten years of schizophrenia respond rapidly to adequate treatment and follow a course of steady improvement.


Assuntos
Antipsicóticos , Risperidona , Humanos , Antipsicóticos/uso terapêutico , Método Duplo-Cego , Piperazinas/uso terapêutico , Escalas de Graduação Psiquiátrica , Risperidona/uso terapêutico , Resultado do Tratamento
16.
Int J Mol Sci ; 24(16)2023 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-37629114

RESUMO

SARS-CoV-2 infection might cause a critical disease, and patients' follow-up is based on multiple parameters. Oxidative stress is one of the key factors in the pathogenesis of COVID-19 suggesting that its level could be a prognostic marker. Therefore, we elucidated the predictive value of the serum non-enzymatic total antioxidant capacity (TAC) and that of the newly introduced TAC/lymphocyte ratio in COVID-19. We included 61 COVID-19 (n = 27 ward, n = 34 intensive care unit, ICU) patients and 29 controls in our study. Serum TAC on admission was measured by an enhanced chemiluminescence (ECL) microplate assay previously validated by our research group. TAC levels were higher (p < 0.01) in ICU (median: 407.88 µmol/L) than in ward patients (315.44 µmol/L) and controls (296.60 µmol/L). Besides the classical parameters, both the TAC/lymphocyte ratio and TAC had significant predictive values regarding the severity (AUC-ROC for the TAC/lymphocyte ratio: 0.811; for TAC: 0.728) and acute kidney injury (AUC-ROC for the TAC/lymphocyte ratio: 0.747; for TAC: 0.733) in COVID-19. Moreover, the TAC/lymphocyte ratio had significant predictive value regarding mortality (AUC-ROC: 0.752). Serum TAC and the TAC/lymphocyte ratio might offer valuable information regarding the severity of COVID-19. TAC measured by our ECL microplate assay serves as a promising marker for the prediction of systemic inflammatory diseases.


Assuntos
Antioxidantes , COVID-19 , Humanos , COVID-19/diagnóstico , SARS-CoV-2 , Estresse Oxidativo , Linfócitos
17.
J Phys Chem A ; 127(33): 6916-6923, 2023 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-37561546

RESUMO

The rate coefficient of the reaction of CH3 with HBr was measured and calculated in the temperature range 225-960 K. The results of the measurements performed in a flow apparatus with mass spectrometric detection agree very well with the quasiclassical trajectory calculations performed on a previously developed potential energy surface. The experimental rate coefficients are described well with a double-exponential fit, k1(exp) = [1.44 × 10-12 exp(219/T) + 6.18 × 10-11 exp(-3730/T)] cm3 molecule-1 s-1. The individual rate coefficients below 500 K accord with the available experimental data as does the slightly negative activation energy in this temperature range, -1.82 kJ/mol. At higher temperatures, the activation energy was found to switch sign and it rises up to about an order of magnitude larger positive value than that below 500 K, and the rate coefficient is about 50% larger at 960 K than that around room temperature. The rate coefficients calculated with the quasiclassical trajectory method display the same tendencies and are within about 8% of the experimental data between 960 and 300 K and within 25% below that temperature. The significant variation of the magnitude of the activation energy can be reconciled with the tabulated heats of formation only if the activation energy of the reverse CH4 + Br reaction also significantly increases with the temperature.

18.
Immunity ; 56(8): 1894-1909.e5, 2023 08 08.
Artigo em Inglês | MEDLINE | ID: mdl-37421943

RESUMO

Infancy and childhood are critical life stages for generating immune memory to protect against pathogens; however, the timing, location, and pathways for memory development in humans remain elusive. Here, we investigated T cells in mucosal sites, lymphoid tissues, and blood from 96 pediatric donors aged 0-10 years using phenotypic, functional, and transcriptomic profiling. Our results revealed that memory T cells preferentially localized in the intestines and lungs during infancy and accumulated more rapidly in mucosal sites compared with blood and lymphoid organs, consistent with site-specific antigen exposure. Early life mucosal memory T cells exhibit distinct functional capacities and stem-like transcriptional profiles. In later childhood, they progressively adopt proinflammatory functions and tissue-resident signatures, coincident with increased T cell receptor (TCR) clonal expansion in mucosal and lymphoid sites. Together, our findings identify staged development of memory T cells targeted to tissues during the formative years, informing how we might promote and monitor immunity in children.


Assuntos
Tecido Linfoide , Células T de Memória , Criança , Humanos , Lactente , Linfócitos T CD8-Positivos , Memória Imunológica , Tecido Linfoide/metabolismo , Mucosa , Receptores de Antígenos de Linfócitos T/genética , Receptores de Antígenos de Linfócitos T/metabolismo , Recém-Nascido , Pré-Escolar
19.
Int J Mol Sci ; 24(14)2023 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-37511327

RESUMO

The dental prophylactic cleaning of a damaged resin-based composite (RBC) restoration with sodium bicarbonate can change the surface characteristics and influence the repair bond strength. The purpose of this study was to compare the effect of sodium bicarbonate (SB) and aluminum oxide (AO) surface treatments on the microtensile bond strength (µTBS) of repaired, aged RBC. Bar specimens were prepared from microhybrid RBC and aged in deionized water for 8 weeks. Different surface treatments (AO air-abrasion; SB air-polishing), as well as cleaning (phosphoric acid, PA; ethylene-diamine-tetraacetic-acid, EDTA) and adhesive applications (single bottle etch-and-rinse, ER; universal adhesive, UA), were used prior to the application of the repair RBC. Not aged and aged but not surface treated RBCs were used as positive and negative controls, respectively. The repaired blocks were cut into sticks using a precision grinding machine. The specimens were tested for tensile fracture and the µTBS values were calculated. Surface characteristics were assessed using scanning electron microscopy. AO-PA-UA (62.6 MPa) showed a 20% increase in µTBS compared to the NC (50.2 MPa), which proved to be the most significant. This was followed by SB-EDTA-UA (58.9 MPa) with an increase of 15%. In addition to AO-PA-UA, SB-EDTA-UA could also be a viable alternative in the RBC repair protocol.


Assuntos
Resinas Compostas , Colagem Dentária , Resinas Compostas/química , Óxido de Alumínio/química , Bicarbonato de Sódio , Ácido Edético , Propriedades de Superfície , Microscopia Eletrônica de Varredura , Materiais Dentários , Resistência à Tração , Teste de Materiais , Cimentos de Resina/química
20.
BMC Complement Med Ther ; 23(1): 168, 2023 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-37226152

RESUMO

BACKGROUND: Essential oils are becoming increasingly popular in medicinal applications because of their antimicrobial effect. Thymus vulgaris L. (Lamiaceae) is a well-known and widely cultivated medicinal plant, which is used as a remedy for cold, cough and gastrointestinal symptoms. Essential oil content of thyme is responsible for its antimicrobial activity, however, it has been reported that the chemical composition of essential oils influences its biological activity. In order to explore flowering phenophases influence on the chemical composition of thyme essential oil and its antibacterial and anti-biofilm activity, plant materials were collected at the beginning of flowering, in full bloom and at the end of flowering periods in 2019. METHODS: Essential oils from fresh and dried plant materials were distilled and analyzed with gas chromatography-mass spectrometry (GC-MS) and gas chromatography-flame ionization detection (GC-FID). The antibacterial activity was performed by broth microdilution and thin layer chromatography-direct bioautography (TLC-DB) assays and the anti-biofilm effect by crystal violet assay, respectively. Scanning electron microscopy was applied to illustrate the cellular changes of bacterial cells after essential oil treatment. RESULTS: Thymol (52.33-62.46%) was the main component in the thyme essential oils. Thyme oil distilled from fresh plant material and collected at the beginning of flowering period exerted the highest antibacterial and anti-biofilm activity against Haemophilus influenzae, H. parainfluenzae and Pseudomonas aeruginosa. CONCLUSION: The different flowering periods of Thymus vulgaris influence the antibacterial and anti-biofilm activity of its essential oils, therefore, the collection time has to be taken into consideration and not only the full bloom, but the beginning of flowering period may provide biological active thyme essential oil.


Assuntos
Óleos Voláteis , Thymus (Planta) , Óleos Voláteis/farmacologia , Cromatografia Gasosa-Espectrometria de Massas , Antibacterianos/farmacologia
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