RESUMO
Felsenstein's application of the bootstrap method to evolutionary trees is one of the most cited scientific papers of all time. The bootstrap method, which is based on resampling and replications, is used extensively to assess the robustness of phylogenetic inferences. However, increasing numbers of sequences are now available for a wide variety of species, and phylogenies based on hundreds or thousands of taxa are becoming routine. With phylogenies of this size Felsenstein's bootstrap tends to yield very low supports, especially on deep branches. Here we propose a new version of the phylogenetic bootstrap in which the presence of inferred branches in replications is measured using a gradual 'transfer' distance rather than the binary presence or absence index used in Felsenstein's original version. The resulting supports are higher and do not induce falsely supported branches. The application of our method to large mammal, HIV and simulated datasets reveals their phylogenetic signals, whereas Felsenstein's bootstrap fails to do so.
Assuntos
Interpretação Estatística de Dados , Conjuntos de Dados como Assunto , HIV-1/genética , Mamíferos/genética , Filogenia , Animais , Simulação por Computador , Código de Barras de DNA Taxonômico , Haplorrinos/genética , Produtos do Gene pol do Vírus da Imunodeficiência Humana/química , Produtos do Gene pol do Vírus da Imunodeficiência Humana/genéticaRESUMO
OBJECTIVES: This study aimed to prospectively explore the association between early lifetime exposure to psychosocial adversity and engagement in health risk behaviours (HRBs) during early adolescence. STUDY DESIGN: This was a prospective study. METHODS: This study used data from the baseline (2005-2006), third (2016-2017) and fourth waves (2018-2020) of the Generation XXI birth cohort. Socio-economic circumstances (SECs) at baseline, adverse childhood experiences (ACEs; e.g. abuse, neglect, household dysfunction) at age 10 years and HRBs (i.e. alcohol consumption, smoking, physical exercise level, sedentary behaviours, sleep duration and eating behaviours) at age 13 years were measured. Patterns of HRBs were obtained using latent class analysis. Latent class regression analysis was used to estimate the likelihood of being engaged in HRBs according to the extent of exposure to ACEs (i.e. 0 ACEs, 1-3 ACEs, 4-5 ACEs and ≥6 ACEs) and negative family SECs. RESULTS: Adolescents whose mothers had a low level of education (adjusted odds ratio [aOR] = 2.72 [95% confidence interval {CI}, 2.33-3.18]), low occupational status (aOR = 3.21 [95% CI, 2.68-3.85]) and low income (aOR = 2.70 [95% CI, 2.23-3.28]) were more likely to be engaged in HRBs than their peers with higher SECs. Adolescents who experienced more ACEs were at a significantly increased risk of involvement in HRBs (aOR = 1.86 [95% CI, 1.33-2.63] for 4-5 ACEs vs aOR 2.41 [95% CI, 1.72-3.43] for ≥6 ACEs). No significant gender differences were observed. CONCLUSIONS: Adolescents from families with low SECs were more likely than their more affluent counterparts to be engaged in HRBs. Furthermore, more ACEs contributed to widening health inequalities.
Assuntos
Maus-Tratos Infantis , Comportamentos de Risco à Saúde , Humanos , Criança , Adolescente , Estudos Prospectivos , Coorte de Nascimento , Maus-Tratos Infantis/psicologia , Análise por ConglomeradosRESUMO
BACKGROUND: Cardiorespiratory fitness (CRF) prompts antiatherogenic adaptations in vascular function and structure. However, there is an extraordinary interindividual variability in response to a standard dose of exercise, wherein a substantial number of adults with intellectual and developmental disabilities (IDD) do not improve CRF. We (1) evaluated the effects of 12-month of moderate-intensity continuous training (MICT) on CRF and arterial stiffness and (2) tested whether an additional 3-month of high-intensity interval training (HIIT) would add to improvements in CRF responsiveness and arterial stiffness. METHODS: Fifteen adults with mild-to-moderate IDD (male adults = 9, 30.1 ± 7.5 years old) met 3 days per week for 30 min MICT for 12 months, after which the incidence of CRF responsiveness was calculated (≥5.0% change in absolute peak VO2 ). Thereafter, responders and non-responders started HIIT for 3 months with identical daily training load/frequency. Peak VO2 , local and regional indices of arterial stiffness were assessed prior to and after each period. RESULTS: Sixty per cent of the participants were non-responders following MICT, but the incidence dropped to 20% following HIIT (P = 0.03). Absolute peak VO2 values reached significant difference from pre-intervention (+0.38 ± 0.08 L min-1 , P = 0.001) only when HIIT was added. Lower limb pulse wave velocity (PWV) decreased following MICT (-0.8 ± 1.1 m s-1 , P = 0.049), whereas central PWV only decreased following HIIT (-0.8 ± 0.9 m s-1 , P = 0.013). CONCLUSIONS: Cardiorespiratory fitness responsiveness and reductions in PWV to a 12-month MICT period in adults with IDD improved following a period of HIIT programme inducing higher metabolic stress.
Assuntos
Aptidão Cardiorrespiratória , Treinamento Intervalado de Alta Intensidade , Rigidez Vascular , Adulto , Criança , Deficiências do Desenvolvimento , Humanos , Masculino , Análise de Onda de Pulso , Adulto JovemRESUMO
Polymer-based actuators play a key role in the area of smart materials and devices, and for this reason different polymer-based actuators have appeared in recent years and are implemented in a broad range of fields, including biomedical, optical or electronics, among others. Although it is possible to find more types, they are mainly classified into two main groups according to their different working principles: electromechanical - with electrical to mechanical energy conversion - and magnetomechanical - with magnetic to mechanical energy conversion. The present work provides a comprehensive and critical review of the recent studies in this field. The operating principles, some representative designs, performance analyses and practical applications will be presented. The future development perspectives of this interesting field will be also discussed. Thus, the present work provides a comprehensive understanding of the effects reported in the past, introduces solutions to the present limitations and, back to the future, serves as a useful guidance for the design of new polymer-based actuators aiming to improve their output performances.
RESUMO
In this work, a new tool was developed, the MORIA program that readily translates Rutherford backscattering spectrometry (RBS) output data into visual information, creating a display of the distribution of elements in a true three-dimensional (3D) environment. The program methodology is illustrated with the analysis of yeast Saccharomyces cerevisiae cells, exposed to copper oxide nanoparticles (CuO-NP) and HeLa cells in the presence of gold nanoparticles (Au-NP), using different beam species, energies and nuclear microscopy systems. Results demonstrate that for both cell types, the NP internalization can be clearly perceived. The 3D models of the distribution of CuO-NP in S. cerevisiae cells indicate the nonuniform distribution of NP in the cellular environment and a relevant confinement of CuO-NP to the cell wall. This suggests the impenetrability of certain cellular organelles or compartments for NP. By contrast, using a high-resolution ion beam system, discretized agglomerates of Au-NP were visualized inside the HeLa cell. This is consistent with the mechanism of entry of these NPs in the cellular space by endocytosis enclosed in endosomal vesicles. This approach shows RBS to be a powerful imaging technique assigning to nuclear microscopy unparalleled potential to assess nanoparticle distribution inside the cellular volume.
RESUMO
The aim of this work was to determine the influence of the biomaterial environment on human mesenchymal stem cell (hMSC) fate when cultured in supports with varying topography. Poly(vinylidene fluoride) (PVDF) culture supports were prepared with structures ranging between 2D and 3D, based on PVDF films on which PVDF microspheres were deposited with varying surface density. Maintenance of multipotentiality when cultured in expansion medium was studied by flow cytometry monitoring the expression of characteristic hMSCs markers, and revealed that cells were losing their characteristic surface markers on these supports. Cell morphology was assessed by scanning electron microscopy (SEM). Alkaline phosphatase activity was also assessed after seven days of culture on expansion medium. On the other hand, osteoblastic differentiation was monitored while culturing in osteogenic medium after cells reached confluence. Osteocalcin immunocytochemistry and alizarin red assays were performed. We show that flow cytometry is a suitable technique for the study of the differentiation of hMSC seeded onto biomaterials, giving a quantitative reliable analysis of hMSC-associated markers. We also show that electrosprayed piezoelectric poly(vinylidene fluoride) is a suitable support for tissue engineering purposes, as hMSCs can proliferate, be viable and undergo osteogenic differentiation when chemically stimulated.
Assuntos
Diferenciação Celular , Eletricidade , Células-Tronco Mesenquimais/citologia , Microesferas , Osteogênese , Polivinil/farmacologia , Fosfatase Alcalina/metabolismo , Materiais Biocompatíveis/farmacologia , Biomarcadores/metabolismo , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Forma Celular , Sobrevivência Celular , Células Cultivadas , Meios de Cultura , Citometria de Fluxo , Humanos , Células-Tronco Mesenquimais/efeitos dos fármacos , Células-Tronco Mesenquimais/enzimologia , Células-Tronco Mesenquimais/metabolismo , Osteocalcina/metabolismo , Osteogênese/efeitos dos fármacos , Coloração e RotulagemRESUMO
UNLABELLED: This cross-sectional study involves randomly selected men aged 50 to 99 years and postmenopausal women. Either central fat mass or peripheral fat mass were associated to osteoporosis or osteopenia independently from fat-free body mass and other confounding factors. INTRODUCTION: Obesity and osteoporosis are public health problems that probably share common pathophysiological mechanisms. The question if body fat mass, central or peripheral, is protective or harmful for osteoporosis or osteopenia is not completely resolved. This study aims to investigate the association between osteoporosis or osteopenia, and fat body mass (central and peripheral) independently from fat-free body mass, in men aged 50 to 99 years old and postmenopausal women randomly selected in the community. METHODS: This is a cross-sectional investigation with a random sample of registered population in Niterói Family Doctor Program (FDP), State of Rio de Janeiro, Brazil. Bone mineral density (BMD) and fat-free mass were assessed by dual X-ray absorptiometry (DXA). RESULTS: There was statistically significant bivariate association between bone loss with gender, age, skin color, alcohol consumption at risk dose, use of thiazide, fat-free body mass, and fat body mass (central and peripheral). In the multiple analysis of fat-free body mass, central and peripheral fat body mass showed an independent and protective effect on the presence of osteoporosis or osteopenia (p value <0.001). CONCLUSION: Since both obesity and osteoporosis are public health problems worldwide, strategies aimed at preventing both conditions should be encouraged during aging.
Assuntos
Tecido Adiposo/patologia , Doenças Ósseas Metabólicas/patologia , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Antropometria/métodos , Composição Corporal/fisiologia , Densidade Óssea/fisiologia , Doenças Ósseas Metabólicas/fisiopatologia , Doenças Ósseas Metabólicas/prevenção & controle , Estudos Transversais , Feminino , Humanos , Gordura Intra-Abdominal/patologia , Masculino , Pessoa de Meia-Idade , Osteoporose/patologia , Osteoporose/fisiopatologia , Osteoporose/prevenção & controle , Fatores de Risco , Fatores Sexuais , Pigmentação da PeleRESUMO
This study investigates the effect of electroactivity and electrical charge distribution on the biological response of human bone marrow stem cells (hBMSCs) cultured in monolayer on flat poly(vinylidene fluoride), PVDF, substrates. Differences in cell behaviour, including proliferation, expression of multipotency markers CD90, CD105 and CD73, and expression of genes characteristic of different mesenchymal lineages, were observed both during expansion in basal medium before reaching confluence and in confluent cultures in osteogenic induction medium. The crystallisation of PVDF in the electrically neutral α-phase or in the electroactive phase ß, both unpoled and poled, has been found to have an important influence on the biological response. In addition, the presence of a permanent positive or negative surface electrical charge distribution in phase ß substrates has also shown a significant effect on cell behaviour.
RESUMO
Orthopedic implant failures, primarily attributed to aseptic loosening and implant site infections, pose significant challenges to patient recovery and lead to revision surgeries. Combining piezoelectric materials with ionic liquids as interfaces for orthopedic implants presents an innovative approach to addressing both issues simultaneously. In this study, films of poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) incorporated with 1-ethyl-3-methylimidazolium hydrogen sulfate ([Emim][HSO4]) ionic liquid were developed. These films exhibited strong antibacterial properties, effectively reducing biofilm formation, thereby addressing implant-related infections. Furthermore, stem cell-based differentiation assays exposed the potential of the composite materials to induce osteogenesis. Interestingly, our findings also revealed the upregulation of calcium channel expression as a result of electromechanical stimulation, pointing to a mechanistic basis for the observed biological effects. This work highlights the potential of piezoelectric materials with ionic liquids to improve the longevity and biocompatibility of orthopedic implants. Offering dual-functionality for infection prevention and bone integration, these advancements hold significant potential for advancing orthopedic implant technologies and improving patient outcomes.
RESUMO
This is the first study to examine the genetic diversity of mandacaru cactus (Cereus jamacaru P. DC.). Plants of spineless mandacaru are commonly found in gardens and parks of urban areas in northeastern Brazil. In addition to exploring their ornamental potential, morphological, and genetic characterization may contribute to the development of plant materials that can be used as a source of macromolecules of potential economic interest. The goal of this study was to estimate the genetic variability of spineless mandacaru accessions using random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR) molecular markers, and to characterize their morphology. Ten samples of newly emitted shoots with differentiated areolas and ribs were collected from each accession from the Cactaceous Germplasm Collection of Embrapa Agroindústria Tropical, in Fortaleza, CE. Shoot shape and aspects of spine primordia (presence, location, grouping, and size of spines) were evaluated. The morphological analysis showed that the spineless mandacaru presented spine primordia. Twenty-six RAPD and 15 ISSR primers were polymorphic. A total of 262 markers were obtained, 129 of which were polymorphic. The average polymorphism of ISSR markers was higher than that of RAPD markers. The dendrograms for both analyses showed differentiation between accessions. Nevertheless, the molecular markers detected higher levels of diversity and a different pattern of diversity than those found using morphological markers. The molecular results revealed significant genetic variability both within and between groups.
Assuntos
Cactaceae/genética , Repetições de Microssatélites , Polimorfismo Genético , Cactaceae/anatomia & histologia , Genes de Plantas , Marcadores Genéticos , Filogenia , Análise de Sequência de DNARESUMO
BACKGROUND: Antibiotics are commonly prescribed for respiratory tract infections (RTIs) among older adults in long-term care facilities (LTCFs), and this contributes to the emergence of antimicrobial resistance. The objective of this study was to determine the antibiotic prescribing rate for RTIs among LTCF residents, and to analyse the antibiotic consumption patterns with the AwaRe monitoring tool, developed by the World Health Organization. METHODS: MEDLINE, EMBASE and CINAHL were searched from inception to March 2022. Original articles reporting antibiotic use for RTIs in LTCFs were included in this review. Study quality was assessed using the Joanna Briggs Institute's Critical Appraisal Checklist for Prevalence Data. A random-effects meta-analysis was employed to calculate the pooled estimates. Subgroup analysis was conducted by type of RTI, country, and study start year. RESULTS: In total, 47 articles consisting of 50 studies were included. The antibiotic prescribing rate ranged from 21.5% to 100% (pooled estimate 69.8%, 95% confidence interval 55.2-82.6%). The antibiotic prescribing rate for lower respiratory tract infections (LRTIs) was higher than the rates for viral and general RTIs. Compared with Italy, France and the USA, the Netherlands had lower antibiotic use for LRTIs. A proportion of viral RTIs were treated with antibiotics, and all the antibiotics were from the Watch group. Use of antibiotics in the Access group was higher in the Netherlands, Norway, Switzerland and Slovenia compared with the USA and Australia. CONCLUSION: The antibiotic prescribing rate for RTIs in LTCFs was high, and AWaRe antibiotic use patterns varied by type of RTI and country. Improving antibiotic use may require coordination efforts.
Assuntos
Antibacterianos , Infecções Respiratórias , Humanos , Idoso , Antibacterianos/uso terapêutico , Assistência de Longa Duração , Infecções Respiratórias/tratamento farmacológico , Infecções Respiratórias/epidemiologia , Instalações de Saúde , Instituições de Cuidados Especializados de EnfermagemRESUMO
Helicobacter pylori is a gastroduodenal pathogen that colonizes the human stomach and is the causal agent of gastric diseases. From the clinical and epidemiological point of view, enhancing and improving the growth of this bacterium in liquid media is an important goal to achieve in order to allow the performance of accurate physiological studies. The aim of this work was to optimize three culture conditions that influence the growth of H. pylori in the defined medium Ham s F-12 supplemented with 5 percent fetal bovine serum by using response surface methodology as a statistical technique to obtain the optimal conditions. The factors studied in this experimental design (Box-Behnken design) were the pH of the medium, the shaking speed (rpm) and the percentage of atmospheric oxygen, in a total of 17 experiments. The biomass specific growth rate was the response measured. The model was validated for pH and shaking speed. The percentage of atmospheric oxygen did not influence the growth for the range of values studied. At the optimal values found for pH and shaking speed, 8 and 130 rpm, respectively, a specific growth rate value of 0.164 h-1, corresponding to a maximal concentration of approximately 1.5x108 CFU/ml, was reached after 8 h. The experimental design strategy allowed, for the first time, the optimization of H. pylori growth in a semi-synthetic medium, which may be important to improve physiological and metabolic studies of this fastidious bacterium.
Assuntos
Helicobacter pylori/crescimento & desenvolvimento , Meios de Cultura , Concentração de Íons de HidrogênioRESUMO
We examined a possible relationship between genes responsible for energy metabolism of the brain and addictive behavior in an animal model. We used non-inbred, Swiss mice exposed to a three-bottle free-choice model [water, 5% (v/v) ethanol, and 10% (v/v) ethanol] over a 16-week period, consisting of four phases: acquisition, withdrawal, reexposure, and quinine-adulteration. The mice were then behaviorally classified into three groups: loss-of-control-drinker (preference for ethanol and high levels of consumption during all phases, N = 6), heavy-drinker (preference for ethanol and high levels of consumption during acquisition and reduction during quinine-adulteration, N = 7), and light-drinker (preference for water during all phases, N = 10). Another group only received tap water (ethanol-naive control mice, N = 9). Further analysis using quantitative real-time PCR showed that in mice behaviorally classified as loss-of-control-drinkers, there was a significant inverse correlation between transcript levels of the Hadh gene and those of other energy metabolism genes in the nucleus of the amygdala, suggesting that this pathway may contribute to ethanol consumption in these mice. We conclude that cerebral energy metabolism is involved with ethanol addiction, meriting further study.
Assuntos
Alcoolismo/genética , Tonsila do Cerebelo/citologia , Química Encefálica/fisiologia , Metabolismo Energético , Receptores de GABA-B/metabolismo , Consumo de Bebidas Alcoólicas/genética , Alcoolismo/metabolismo , Animais , Comportamento Aditivo/genética , Modelos Animais de Doenças , Etanol/administração & dosagem , Masculino , CamundongosRESUMO
Cardiac tissue regeneration strategies are increasingly taking advantage of electroactive scaffolds to actively recreate the tissue microenvironment. In this context, this work reports on advanced materials based on two different ionic liquids (ILs), 2-hydroxyethyl-trimethylammonium dihydrogen phosphate ([Ch][DHP]) and choline bis(trifluoromethylsulfonyl)imide ([Ch][TFSI]), combined with poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)) for the development of ionic electroactive IL/polymer hybrid materials for cardiac tissue engineering (TE). The morphological, physico-chemical, thermal and electrical properties of the hybrid materials, as well as their potential use as scaffolds for cardiac TE applications, were evaluated. Besides inducing changes in surface topography, roughness and wettability of the composites, the incorporation of [Ch][DHP] and [Ch][TFSI] leads to the increase in surface (σsurface) and volume (σvolume) electrical conductivities. Furthermore, washing the hybrid samples with phosphate-buffered saline solution strongly decreases the σsurface, whereas σsurface and σvolume of the composites remain almost unaltered after exposure to ultraviolet sterilization treatment. Additionally, it is verified that the incorporation of IL influences the P(VDF-TrFE) microstructure and crystallization process, acting as a defect during its crystallization. Cytotoxicity assays revealed that hybrid films based on [Ch][DHP] alone are not cytotoxic. These films also support H9c2 myoblast cell adhesion and proliferation, demonstrating their suitability for cardiac TE strategies based on electroactive microenvironments.
Assuntos
Líquidos Iônicos , Engenharia Tecidual , Condutividade Elétrica , Líquidos Iônicos/química , Fosfatos , PolímerosRESUMO
OBJECTIVE/BACKGROUND: To describe and characterize insomnia symptoms and nightmare profiles in Portugal during the first six weeks of a national lockdown due to COVID-19. PATIENTS/METHODS: An open cohort study was conducted to collect information of the general population during the first wave of SARS-CoV-2/COVID-19 pandemic in Portugal. We analyzed data from 5011 participants (≥16 years) who answered a weekly questionnaire about their well-being. Two questions about the frequency of insomnia and nightmares about COVID-19 were consecutively applied during six weeks (March-May 2020). Latent class analysis was conducted and different insomnia and nightmare profiles were identified. Associations between individual characteristics and both profiles were estimated using odds ratios (ORs) and 95% confidence intervals (CI). RESULTS: Five insomnia (No insomnia, Stable-mild, Decreasing-moderate, Stable-severe, Increasing-severe) and three nightmares profiles (Stable-mild, Stable-moderate, Stable-severe) were identified. Being female, younger, perceiving their income as insufficient and feelings of fear towards COVID-19 were associated with higher odds of insomnia (Women: OR = 6.98 95%CI: 4.18-11.64; ≥60 years: OR = 0.30 95%CI: 0.18-0.53; Insufficient income: adjusted OR (aOR) = 8.413 95%CI: 3.93-16.84; Often presenting fear of being infected with SARS-CoV-2 infection: aOR = 9.13 95%CI: 6.36-13.11), and nightmares (Women: OR = 2.60 95%CI: 1.74-3.86; ≥60 years: OR = 0.45 95%CI: 0.28-0.74; Insufficient income: aOR = 2.60 95%CI: 1.20-5.20; Often/almost always presenting fear of being infected with SARS-CoV-2 infection: aOR = 6.62 95%CI: 5.01-8.74). Having a diagnosis of SARS-CoV-2 virus infection was associated with worse patterns of nightmares about the pandemic. CONCLUSIONS: Social and psychological individual factors are important characteristics to consider in the development of therapeutic strategies to support people with sleep problems during the COVID-19 pandemic.
Assuntos
COVID-19 , Distúrbios do Início e da Manutenção do Sono , COVID-19/epidemiologia , Estudos de Coortes , Controle de Doenças Transmissíveis , Sonhos , Feminino , Humanos , Pandemias , Portugal/epidemiologia , SARS-CoV-2 , Distúrbios do Início e da Manutenção do Sono/epidemiologiaRESUMO
AIMS: This study aimed to investigate the effect of copper sulfate (from 0 to 8 mmol kg(-1)) on radial growth rate and lag time of two moulds responsible for vine grapes spoilage: Penicillium expansum strain 25·03 and Botrytis cinerea, strains BC1 and BC2. METHODS AND RESULTS: A new model was developed to describe tailing and shoulders in the inhibition curves. Because of tailing, the minimum inhibitory concentration (MIC), was not defined as the concentration at which no growth was observed, but as the concentration at which the lag time was infinite. The concentrations at which µ = µ(opt)/2, (Cu50), were in the range of 2·2-2·6 mmol kg(-1). Radial growth rate of P. expansum and the reciprocal of the lag time were linearly correlated (r = 0·84). In contrast, in the range 0-4 mmol kg(-1), an inhibition of growth of B. cinerea was observed whereas germination remained unaffected (i.e. the lag time was constant). In the range 4-8 mmol kg(-1) , the radial growth rate of B. cinerea was almost constant (c. 1 mm day(-1)), but germination was inhibited (i.e. the lag time was increased). CONCLUSIONS: The MIC values were 4·7 mmol kg(-1) for P. expansum, 8·2 and 7·3 mmol kg(-1) for B. cinerea strain BC1 and BC2, respectively, demonstrating that some isolates of these moulds are resistant to copper. SIGNIFICANCE AND IMPACT OF THE STUDY: Copper concentrations at 4 mmol kg(-1) would be sufficient to control the development of these isolates, but the toxicity of copper should be extended to other isolates and evaluated in vineyards.
Assuntos
Botrytis/crescimento & desenvolvimento , Sulfato de Cobre/toxicidade , Substâncias Perigosas/toxicidade , Modelos Biológicos , Penicillium/crescimento & desenvolvimento , Botrytis/efeitos dos fármacos , Botrytis/isolamento & purificação , Testes de Sensibilidade Microbiana , Penicillium/efeitos dos fármacos , Penicillium/isolamento & purificação , Vitis/microbiologiaRESUMO
Electrospun poly(vinylidene fluoride) (PVDF) fiber membranes doped with different ionic liquids (ILs) and sharing the same anion were produced and their potential as separator membranes for battery applications was evaluated. Different types of ILs containing the same anion, bis(trifluoromethylsulfonyl)imide [TFSI]-, were used with IL concentrations ranging between 0 and 15 wt% The morphology, microstructure, thermal and electrical properties (ionic conductivity and electrochemical window) of the membranes were evaluated. The presence of ILs in the PVDF polymer matrix influences the fiber diameter and the content of the polar ß phase within the polymer, as well as the degree of crystallinity. The thermal stability of the membranes decreases with the incorporation of IL. Impedance spectroscopy tests show a maximum ionic conductivity of 2.8 mS.cm-1 for 15% of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Emim][TFSI]) at room temperature. The electrochemical stability of the samples ranges from 0.0 to 6.0 V. When evaluated as battery separator membranes in C-LiFePO4 half-cells, a maximum discharge capacity of 119 mAh.g-1 at C-rate was obtained for the PVDF membrane with 15% [Emim][TFSI], with a coulombic efficiency close to 100%. The results demonstrate that the produced electrospun membranes are suitable for applications as separators for lithium ion batteries (LIBs).
RESUMO
PURPOSE: Hyperthermia treatment planning (HTP) potentially provides a valuable tool for monitoring and optimization of treatment. However, one of the major problems in HTP is that different sources of uncertainty degrade its reliability. Perfusion uncertainty is one of the largest uncertainties and hence there is an ongoing debate whether optimization should be limited to power-based strategies. In this study a systematic analysis is carried out addressing this question. METHODS: The influence of perfusion uncertainty on optimization was analyzed for five patients with cervix uteri carcinoma heated with the AMC-8 70 MHz phased-array waveguide system. The effect of variations (up to +/- 50%) in both the muscle and tumor perfusion level was investigated. For every patient, reference solutions were calculated using constrained temperature-based optimization for 25 different and known perfusion distributions. Reference solutions were compared to those found by temperature-based optimization using standard perfusion values and four SAR-based optimization methods. The effect of heterogeneity was investigated by creating 5 x 100 perfusion distributions for different levels of local variation (+/- 25% and +/- 50%) and scale (1 and 2 cm). Here the performance of the temperature-based optimization method was compared to a SAR-based method that showed good performance in the previous analysis. RESULTS: Solutions found with temperature-based optimization using a deviating perfusion distribution during optimization were found within 1.0 degrees C from the true optimum. For the SAR-based methods, deviations up to 2.9 degrees C were found. The spread found in these deviations was comparable, typically 0.5-1.0 degrees C. When applying intramuscle variation to the perfusion, temperature-based optimization proved to be the best strategy in 95% of the evaluated cases applying +/- 50% local variation. CONCLUSIONS: Temperature-based optimization proves to be superior to SAR-based optimization both under variation of perfusion level as well as under the application of intratissue variation. The spread in achieved temperatures is comparable. These results are valid under the assumption of constant perfusion at hyperthermic levels. Although similar results are expected from models including thermoregulation, additional analysis is required to confirm this. In view of uncertainty in tissue perfusion and other modeling uncertainties, the authors propose feedback guided temperature-based optimization as the best candidate to improve thermal dose delivery during hyperthermia treatment.
Assuntos
Hipertermia Induzida/métodos , Perfusão , Incerteza , Neoplasias do Colo do Útero/terapia , Feminino , Humanos , Modelos Biológicos , Doses de Radiação , TemperaturaRESUMO
Ethanol (EtOH) consumption is a primary health risk worldwide, which generally starts during adolescence in a binge pattern (i.e., the episodic consumption of high amounts). Binge EtOH consumption can lead to modifications of the innate and adaptive immune responses, including fever. The present study evaluated the febrile response that was induced by lipopolysaccharide (LPS) and prostaglandins E2 (PGE2) and the mechanisms of thermoregulation in adolescent rats that were exposed to EtOH in a binge-like pattern. Male Wistar rats were treated with an intraperitoneal (i.p.) injection of EtOH or saline on postnatal days (PND) 25, 26, 29, 30, 33, 34, 37, and 38. On PND 51, they received a pyrogenic challenge with LPS (i.p.) or PGE2 (intracerebroventricular) to induce a febrile response. Interscapular brown adipose tissue (BAT) mass and uncoupling protein (UCP) activity in isolated mitochondria were evaluated on PND 51. The rats were then subjected to cold challenges to analyze adaptive thermogenesis. Intermittent EtOH exposure during adolescence impaired the LPS- and PGE2-induced febrile response 12 days after the end of EtOH exposure. Ethanol exposure decreased interscapular BAT mass, oxygen consumption, and UCP activity in isolated mitochondria, resulting in an impairment in thermogenesis at 5 °C. No morphological changes in BAT were observed. These findings indicate that binge-like EtOH exposure during adolescence impairs thermoregulation by reducing BAT mass and function. This reduction may last for a prolonged period of time after the cessation of EtOH exposure and may affect both cold defenses and the febrile response during the development of infectious diseases.
Assuntos
Tecido Adiposo Marrom/metabolismo , Consumo Excessivo de Bebidas Alcoólicas/metabolismo , Etanol/administração & dosagem , Febre/metabolismo , Termogênese/fisiologia , Tecido Adiposo Marrom/efeitos dos fármacos , Fatores Etários , Animais , Etanol/toxicidade , Febre/induzido quimicamente , Masculino , Consumo de Oxigênio/efeitos dos fármacos , Consumo de Oxigênio/fisiologia , Ratos , Ratos Wistar , Termogênese/efeitos dos fármacosRESUMO
The use of piezoelectric materials in tissue engineering has grown considerably since inherent bone piezoelectricity was discovered. Combinations of piezoelectric polymers with magnetostrictive nanoparticles (MNP) can be used to magnetoelectrically stimulate cells by applying an external magnetic field which deforms the magnetostrictive nanoparticles in the polymer matrix, deforming the polymer itself, which varies the surface charge due to the piezoelectric effect. Poly(vinylidene) fluoride (PVDF) is the piezoelectric polymer with the largest piezoelectric coefficients, being a perfect candidate for osteogenic differentiation. As a first approach, in this paper, we propose PVDF membranes containing magnetostrictive nanoparticles and a biomimetic heparin/collagen layer-by-layer (LbL) coating for mesenchymal stem cell culture. PVDF membranes 20% (w/v) with and without cobalt ferrite oxide (PVDF-CFO) 10% (w/w) were produced by non-solvent induced phase separation (NIPS). These membranes were found to be asymmetric, with a smooth surface, crystallinity ranging from 65% to 61%, and an electroactive ß-phase content of 51.8% and 55.6% for PVDF and PVDF-CFO, respectively. Amine groups were grafted onto the membrane surface by an alkali treatment, confirmed by ninhydrin test and X-ray photoelectron spectroscopy (XPS), providing positive charges for the assembly of heparin/collagen layers by the LbL technique. Five layers of each polyelectrolyte were deposited, ending with collagen. Human mesenchymal stem cells (hMSC) were used to test cell response in a short-term culture (1, 3 and 7 days). Nucleus cell counting showed that LbL favored cell proliferation in PVDF-CFO over non-coated membranes.