Abstract This study sought to analyze the practice of physical activity (PA) among university students, during the COVID-19 pandemic, and associated factors. This is a cross-sectional study with an analytical approach, carried out with 857 university students enrolled in higher education institutions in Montes Claros, in the state of Minas Gerais. Data collection was carried out using the Google forms, which was shared via social networks, containing questions regarding sociodemographic profile, physical activity, clinical factors, and behavioral and health habits. A descriptive exploratory analysis of the data was carried out, with frequency distribution of the study variables. Subsequently, bivariate analyses were performed and the associated variables with up to a level of 20% (p ≤ 0.20) were selected for multiple analysis using Poisson Regression. The prevalence non-practice of PA during the pandemic was of 56.8% among college students. Variables, such as being with a partner (PR=1.28), presence of respiratory diseases (PR=1.17), negative self-perception of health (PR=1.37), increased consumption of ultra-processed foods (PR=1.29), and presence of depression (PR=1.21), showed statistically significant associations with the practice of physical activity. We concluded that the non-practice of PA in university students during the social isolation caused by the COVID-19 pandemic is associated with marital status, presence of respiratory diseases, negative self-perception of health, increased consumption of ultra-processed foods, and presence of depression.

Resumo Este estudo buscou analisar a prática de atividade física entre universitários durante a pandemia de COVID19, e os fatores associados. Trata-se de estudo transversal de abordagem analítica, realizado com 857 universitários matriculados em instituições de ensino superior de Montes Claros-Minas Gerais. A coleta de dados foi realizada através do formulário Google forms, divulgado por redes sociais, contendo perguntas referentes ao perfil sociodemográfico, prática de atividade física, fatores clínicos, hábitos comportamentais e de saúde. Realizou-se análise descritiva exploratória dos dados, com distribuição de frequências das variáveis do estudo. Em seguida foram realizadas análises bivariadas e as variáveis associadas até o nível de 20% (p ≤ 0,20) foram selecionadas para a análise múltipla através da Regressão de Poisson. A prevalência de ausência da prática de AF durante a pandemia foi de 56,8% entre os universitários. Variáveis como estar com companheiro (RP=1,28), presença de doenças respiratórias (RP=1,17), autopercepção negativa da saúde (RP=1,37), aumento do consumo de alimentos ultraprocessados (RP=1,29) e presença de depressão (RP=1,21) demonstraram associações estatisticamente significativas com a prática de atividade física. Neste estudo, observou-se elevada prevalência de universitários que não praticam AF durante o isolamento social, sendo associado a diversos fatores, como o estado conjugal, à presença de doenças, hábitos alimentares e a autopercepção do estado de saúde. Dessa forma, tais características podem subsidiar intervenções com o intuito de incentivar hábitos saudáveis e sobretudo, promover a prática de AF como promoção a saúde física e mental.

RESUMO: O objetivo desse estudo foi avaliar a eficiência de métodos mecânicos, físico, químicos e culturais de forma isolada ou integrada, no controle de capim-annoni. O delineamento experimental utilizado foi inteiramente casualizado, com 15 tratamentos e quatro repetições. O controle físico do capim-annoni foi baseado na aplicação de fogo enquanto os controles mecânicos consistiram em roçada e gradagem/aração. Para o controle químico, foram testados os herbicidas clethodim e diferentes sais de glifosato. Para os métodos culturais e integrados, foi realizada aplicação de glifosato isopropilamina + potássio e correção da fertilidade do solo, além dos tratamentos com combinação de isopropilamina + potássio, correção de fertilidade do solo e implantação das seguintes espécies forrageiras: Capim-elefante, Capim Pangola, Amendoim forrageiro e Cornichão. Avaliou-se o efeito dos tratamentos sobre a ocorrência de capim-annoni e sobre a composição botânica, um ano após suas aplicações. Métodos de controle isolados, com exceção do uso de glifosato, não apresentam controle eficiente de plantas de capim-annoni. Os sais de glifosato controlam plantas de capim-annoni, mas sua associação com a melhoria da fertilidade do solo e implantação de Capim Pangola é a melhor estratégia para controle da planta invasora.

ABSTRACT: The current study evaluated the efficiency of mechanical, physical, chemical and cultural methods, used exclusively or integrated, to control tough lovegrass. The experimental design was completely randomized, with 15 treatments and four repetitions. Physical control of tough lovegrass was based on the application of fire, whereas mechanical controls consisted in mowing and harrowing/plowing procedures. The herbicide clethodim and different glyphosate salts were evaluated for chemical control. Glyphosate and soil fertility correction were applied as cultural and integrated methods, in addition to isopropylamine + potassium salts combination, soil fertility correction and implantation of one of the following forage plants: Elephant grass, Pangola grass, Forage peanut and Birdsfoot trefoil. The effect of treatments on the incidence of tough lovegrass and on its botanical composition was evaluated one year after their applications. Isolated control methods, except for glyphosate using, did not present efficient tough lovegrass control. Glyphosate salts could control tough lovegrass plants, but their association with improved soil fertility and Pangola grass implantation was the best strategy to control the invasive plant.

ABSTRACT This study aimed at analyzing and comparing the phenotypic characteristics of height, body length, and fleece wool fineness with the liquidity and final price sold in auctions in the city of Uruguaiana, RS, Brazil, for three consecutive years (2015 to 2017). A total of 412 one-year-old (two teeth) male sheep, of the Australian Merino (n = 50), Polwarth (n = 130), and Corriedale (n = 232) breeds were evaluated. Height and length of the animals were measured on the day of the auction with a measuring tape, and animals were grouped into small or tall and short or long categories, as defined in this study. Wool fineness was measured using an Optical-based Fibre Diameter Analyser (FDA 2000) device and classified according to official wool classification standards (the Bradford System). There was no statistical difference in the average selling price of different breeds. There was a correlation between the breed and liquidity, in which Corriedale lambs were sold more than the Polwarth lambs, as expected; however, there was no such correlation for Merino lambs. The tall Merino lambs were sold at a higher selling price (R$ 2,449.11) than the small ones (R$ 1,826.59). Polwarth lambs exhibited positive correlations among height, length, and liquidity. Long and tall Corriedale lambs had a higher selling price (R$ 1,963.40 and R$ 1,915.02) than the short (R$ 1,656.38) and small (R$ 1,698.20) ones, respectively. In the case of Corriedale lambs, there was a positive correlation between length and liquidity. Wool fineness did not influence the selling price and liquidity in the three studied breeds. Conclusively, buyers of the Polwarth and Corriedale lambs prefer tall and long animals, regardless of the fleece wool fineness; only the height (taller lambs) seems to be a relevant factor for choosing the Merino breeders.

RESUMO: O objetivo do trabalho foi avaliar a eficiência de uso de herbicidas no controle de capim-annoni em função da disponibilidade de radiação solar e da presença ou ausência de lâmina de água. Para isso, foram conduzidos dois experimentos em delineamento inteiramente casualizado, em esquema fatorial 2x2x4 e 2x2x5, em que o fator A equivaleu ao ambiente (radiação natural ou reduzida); fator B à condição hídrica (com lâmina d’água de 2 cm ou sem); e, o fator C aos herbicidas: cyhalofop butyl (315 g ha-1), glyphosate (1080 g ha-1), cyhalofop butyl + glyphosate (315 g ha-1+ 1080 g ha-1) e testemunha (sem aplicação) no primeiro experimento. No segundo experimento, os herbicidas utilizados foram: cyhalofop butyl (315 g ha-1), glyphosate (1080 g ha-1), sethoxydim (184 g ha-1), imazethapyr (106 g ha-1) e testemunha (sem aplicação). Glyphosate controla eficientemente plantas de capim-annoni com quatro afilhos (>90%), sendo superior a cyhalofop butyl, imazethapyr e sethoxydim, independente das condições. A redução da disponibilidade de radiação solar gera menor produção de matéria seca da parte aérea pelo capim-annoni, podendo inclusive, contribuir para maior eficiência de controle somente por imazethapyr e cyhalofop. De maneira geral, a condição de lâmina d’água não afeta o controle de capim-annoni pelos herbicidas.

ABSTRACT: The objective of the study was to evaluate the efficiency of herbicides use in the control of tough lovegrass according to the availability of solar radiation and the presence or absence of flooded. Two experiments were conducted in a completely randomized design, in a 2x2x4 and 2x2x5 factorial scheme, where factor A was equivalent to the environment (natural or reduced radiation); factor B to water condition (with a 2 cm flooded or without); and, factor C the herbicides: cyhalofop butyl (315 g ha-1), glyphosate (1080 g ha-1), cyhalofop butyl + glyphosate (315 g ha-1 + 1080 g ha-1) and control (without application) in the first experiment. In the second experiment, the herbicides used were cyhalofop butyl (315 g ha-1), glyphosate (1080 g ha-1), sethoxydim (184g ha-1), imazethapyr (106 g ha-1) and control (without application). Glyphosate efficiently controls plants of tough lovegrass with four tillers (>90%), being superior to cyhalofop, imazethapyr and sethoxydim; independently, of resource conditions. Reduction in the availability of solar radiation generates less shoot dry mass production from the weed, and improves the control only by imazethapyr and cyhalofop. In general, a flooded condition does not affect tough lovegrass control by herbicides.

RESUMO Este estudo foi conduzido com o objetivo de avaliar os efeitos de diferentes alturas pré e pós colheita de milheto, capim-sudão e sorgo forrageiro sobre a produção de forragens e a composição morfológica e bromatológica. O experimento foi conduzido em delineamento em blocos casualizados, com quatro unidades experimentais por tratamento. Foram avaliadas três espécies forrageiras: 1) Milheto (MIL; Pennisetum americanum); 2) Capim-Sudão (SUD; Sorghum sudanense); e 3) Sorgo (SOR; Sorghum bicolor); e dois manejos de cortes: I) 50:20: com 50 cm de altura de corte e 20 cm de altura residual; e II) 85:10: com 85 e 10 cm de altura de corte e residual, respectivamente. Foram avaliados a produção, o número de cortes, e a composição morfológica e bromatológica. Não houve diferenças entre as espécies na produção por corte e na produção total, independentemente do manejo de cortes. O SUD apresentou menor número de cortes que MIL e SOR, quando submetido ao manejo 50:20. O manejo 85:10 aumentou a proporção de caule e a razão folha:caule em relação ao manejo 50:20. O manejo 50:20 reduziu os teores de fibra e matéria orgânica, enquanto aumentou os teores de proteína bruta e nutrientes digestíveis totais na forragem. O SOR tem um maior valor nutricional devido à maior proporção de folhas. O manejo 50:20 aumenta o número de cortes e o potencial nutricional, independentemente da espécie forrageira avaliada.

ABSTRACT This study aimed to evaluate the effects of different pre-cutting and residual heights of Pearl millet, Sudangrass, and Sorghum pastures on yield, morphological and chemical composition. The experimental design was the randomized blocks, with four experimental units per treatment. It was evaluated three species of forage: 1) Pearl millet (MIL; Pennisetum americanum); 2) Sudangrass (SUD; Sorghum sudanense); and 3) Sorghum (SOR; Sorghum bicolor); and two cutting managements: I) 50:20 - cutting height at 50 cm and 20 cm residual height; and II) 85:10 - cutting height at 85 cm and 10 cm residual height. Managements of cutting height affected neither forage yield per cut nor total forage yield. Sudangrass had less cuts than MIL and SOR when submitted to the 50:20 management. The 85:10 management increased stem proportion and leaf to stem ratio, and reduced leaf proportion in comparison with the 50:20 management. The 50:20 management reduced forage contents of fiber and organic matter, and increased forage contents of crude protein and total digestible nutrient. Sorghum exhibited greater nutritive value due to increased leaf proportion. The 50:20 management increased number of cuts and improved nutritive value of forages, regardless of species evaluated in this study.

Abstract The species Kalanchoe laciniata (L.) DC. and Bryophyllum pinnatum (Lam) Pers. are native from Brazil and Madagascar, respectively. Both belonging to the Crassulaceae family and being widely used by population as a natural anti-inflammatory agent. These species have similar leaf morphology and for this reason, they are known by the same popular name as “ saião ” or “ coirama ”. Several studies have been published involving different parts and preparations of these species. Therefore, this review aims to provide an update overview about the traditional uses, chemical constitution, pharmacology and toxicology of K. laciniata and B. pinnatum species. An extensive literature review was conducted in different scientific databases. Various chemical constituents have been identified in extracts from different parts of K. laciniata and B. pinnatum , being flavonoids the major compounds. They have been traditionally used to treat inflammation, microbial infection, pain, respiratory diseases, gastritis, ulcers, diabetes and cancer tumors. Non-clinical in vitro assays evaluated mainly the antimicrobial and antioxidant activities, while in vivo assays evaluated the leishmanicide, anti-inflammatory and immunomodulatory activities. Regarding toxicity, few studies have been conducted for the two species. The information reported in this work might contribute to the recognition of the importance of K. laciniata and B. pinnatum species, as well as to direct further studies.

RESUMO A natureza sempre se forneceu uma fonte inesgotável compostos biologicamente ativos. Desde o início da humanidade, os homens buscaram recursos na fauna e flora para tratar as doenças oculares. Porém, foi somente após a Revolução Industrial que extratos de plantas e substâncias de origem animal puderam ser utilizados com segurança, como foi determinado por estudos controlados de intervenção. Dois grandes desafios enfrentados pela farmacologia foram: desenvolver drogas capazes de reduzir a cegueira pelo glaucoma; e controlar a dor associada à cirurgia ocular. A busca por uma droga que efetivamente reduza a pressão intraocular e controle a progressão do glaucoma levou ao desenvolvimento de diversos hipotensores oculares, como a physostigmine da planta Physostigma venenosum. As propriedades anestésicas da cocaína, extraídas da Erythroxylon coca, finalmente permitiram procedimentos cirúrgicos no olho. Vários novos compostos naturais foram investigados na tentativa de identificar substâncias com potencial para fornecer benefícios adicionais ao tecido ocular e à visão. Evidências emergentes de propriedades anti-inflamatórias, de cicatrização de feridas, antimicrobianas, antioxidantes, antitumorais e antiangiogênicas atribuídas a extratos de plantas e tecidos animais estimularam mais investimentos em pesquisas nessa área. Apesar dos avanços tecnológicos na síntese de drogas, a indústria farmacêutica ainda busca novos princípios ativos a partir de fontes naturais, bem como revisita drogas derivadas já estabelecidas. Embora um grande número de compostos que ocorrem naturalmente seja conhecido, este artigo de revisão concentra-se nas substâncias bioativas com benefícios cientificamente comprovados para os tecidos oculares.

ABSTRACT Nature has always provided an unlimited source of biologically-active compounds. Since the beginning of mankind, humans have sought resources in fauna and flora to treat eye diseases. However, it was only after the Industrial Revolution that extracts of plants and substances of animal origin could be used safely, as has been determined by controlled interventional studies. Two major challenges faced by ocular pharmacology are the following: developing drugs that are able to reduce blindness due to glaucoma; and controlling the pain associated with eye surgery. The search for a drug that effectively lowers intraocular pressure and controls the progression of glaucoma has led to the development of various ocular hypotensive agents, such as physostigmine from the Physostigma venenosum plant. The anesthetic properties of cocaine, extracted from Erythroxylon coca, finally enabled surgical procedures in the eye. Several new natural compounds have been investigated in an attempt to identify substances with the potential to provide additional benefits to eye tissue and vision. Emerging evidence of anti-inflammatory, wound-healing, antimicrobial, antioxidant, antitumor, and antiangiogenic properties attributed to plant extracts and animal tissues has encouraged more investment in research in this area. Despite technological advances in synthesizing drugs, the pharmaceutical industry still seeks new active compounds from natural sources as well as from revisiting already-established naturally derived compounds. Although a large number of naturally-occurring compounds is known, this review article focuses on the bioactive substances with scientifically-proven benefits for ocular tissues.

SUMMARY: Mesenchymal cells (MCs) exhibit great regenerative potential due to their intrinsic properties and ability to restore tissue function, either directly through transdifferentiation or indirectly through paracrine effects. This study aimed to evaluate morphometric and phenotypic changes in MCs grown with facial nerve-conditioned medium in the presence or absence of fibroblast growth factor 2 (FGF-2). For quantitative phenotypic analysis, the expression of GFAP, OX-42, MAP-2, β-tubulin III, NeuN, and NF-200 was analyzed by immunocytochemistry. Cells cultured with facial nerve-conditioned medium in the presence of FGF-2 expressed GFAP, OX-42, MAP-2, β-tubulin III, NeuN, and NF-200. On average, the area and perimeter of GFAP-positive cells were higher in the group cultured with facial nerve-conditioned medium compared to the group cultured with conditioned medium and FGF-2 (p=0.0001). This study demonstrated the plasticity of MCs for neuronal and glial lineages and opens up new research perspectives in cell therapy and trans.differentiation.

RESUMEN: Las células mesenquimales (CM) exhiben un gran potencial regenerativo debido a sus propiedades intrínsecas y la capacidad de restaurar la función del tejido, ya sea directamente, a través de la transdiferenciación, o indirectamente, a través de efectos parácrinos. Este estudio tuvo como objetivo evaluar los cambios morfométricos y fenotípicos en CM cultivadas con medio condicionado por nervio facial en presencia o ausencia de factor de crecimiento de fibroblastos 2 (FGF-2). Para el análisis fenotípico cuantitativo, se analizó la expresión de GFAP, OX-42, MAP-2, β-tubulina III, NeuN y NF-200 mediante inmunocitoquímica. Las células cultivadas con medio condicionado por el nervio facial en presencia de FGF-2 expresaban GFAP, OX-42, MAP-2, β-tubulina III, NeuN y NF-200. En promedio, el área y el perímetro de las células positivas para GFAP fueron mayores en el grupo cultivado con medio condicionado por el nervio facial en comparación con el grupo cultivado con medio acondicionado y FGF-2 (p = 0,0001). Este estudio demostró la plasticidad de CM para linajes neuronales y gliales y abre nuevas perspectivas de investigación en terapia celular y transdiferenciación.

RESUMO A deficiência de zinco (Zn) no solo e plantas e seu baixo estado nutricional na população estimulam estudos sobre enriquecimento de produtos agrícolas. A cenoura tem potencial para o enriquecimento, pois é um vegetal comumente consumido. O objetivo deste estudo foi avaliar as fontes de Zn (ZnO, ZnSO4 ou ZnEDTA) e a dose (0, 5, 10, 20 and 30 mg dm-3) aplicadas no solo a fim de aumentar a concentração do mineral na parte comestível da cenoura. ZnSO4 foi mais adequado para esse papel, porque apresentou maior acúmulo com o aumento da dose de tratamento. A melhor dose foi 19.45 mg dm-3 de ZnSO4, a qual apresentou maior teor de Zn nas cenouras. Além disso, este tratamento aumentou o teor de Zn na raiz em 7 vezes comparado com o controle. O baixo custo da produção de cenouras enriquecidas com Zn as torna uma hortaliça potencial para a redução da deficiência deste micronutriente na nutrição populacional.

ABSTRACT Zinc (Zn) deficiency in soil and plants and its low nutritional status in the population encourage studies on enrichment of agricultural products. Carrot has potential to enrichment because it is a commonly consumed vegetable. The objective of this study was to evaluate Zn sources (ZnO, ZnSO4, or ZnEDTA) and doses (0, 5, 10, 20, and 30 mg dm-3) applied to the soil to increase the concentration of this mineral in the carrot edible part. Zinc sulfate was the most suitable source for this role because it had a higher accumulation with the increase of treatment dose. The best dose was 19.45 mg dm-3 of ZnSO4, which resulted the highest content of Zn in carrots. Moreover, this treatment increased Zn in the root by seven times compared with the control. The low production cost of Zn enrichment of carrots makes them a potential vegetable for the deficiency reduction of this micronutrient in the population nutrition.

RESUMO: O objetivo deste trabalho foi avaliar a dispersão endozoocórica, recuperação e germinação de sementes de arroz daninho (Oryza sativa L.) e capim-arroz (Echinochloa crus-galli L.) passadas pelo sistema digestivo de bovinos. O experimento foi dividido em duas fases: primeiramente determinou-se a taxa de recuperação diária das sementes após passagem pelo sistema digestivo de seis bovinos. Foram dosadas individualmente 1000 sementes de arroz daninho e 13818 sementes de capim-arroz para cada animal e posteriormente coletadas nas fezes. Na segunda fase foi determinada a taxa de germinação e emergência de sementes com e sem passagem pelo sistema digestivo de bovinos em dois tipos de substratos (placa fecal ou solo) em delineamento fatorial 2x2. A recuperação de sementes nas fezes apresentou comportamento sigmoide com máxima recuperação no 2° dia após dosagem. A recuperação nas fezes foi de 50,9% e 23,4%, para arroz daninho e capim-arroz, o que demonstra que ambas apresentam potencial de dispersão endozoocórica. Porém, a germinação de sementes destas espécies reduziu ao passar pelo sistema digestivo, e na placa fecal apresentou emergência inferior em comparação ao solo. O período de quarentena para animais que ingerirem sementes de arroz daninho e capim-arroz deve ser de no mínimo 6 e 7 dias, respectivamente.

ABSTRACT: The objective of this study was to evaluate endozoochory dispersal, recuperation, and germination of weedy rice (Oryza sativa L.) and barnyardgrass (Echinochloa crus-galli L.) seeds passed through the digestive system of cattle. The experiment was divided into two phases: first, the daily seed recuperation rate was determined after passing through the digestive system of six steers. Each animal was dosed individually with 1000 weedy rice seeds and 13,818 barnyardgrass seeds, and these seeds were subsequently collected from feces. In the second phase, seed germination and emergence rate after passing or not passing through the digestive system of cattle were determined in two types of substrates (fecal plaque and soil) in a 2×2 factorial design. Seed recuperation in feces showed sigmoid behavior with maximum recovery on the second day after dosage. The recuperation of the species in the feces was 50.9% and 23.4% for weedy rice and barnyardgrass, respectively, which shows that both have potential endozoochory dispersal. However, seed germination of these species reduced after they passed through the digestive system, and they presented inferior emergence in the fecal plaque compared to the soil. The quarantine period for animals that ingest weedy rice and barnyardgrass seeds should be at least 6 and 7 days, respectively.

Resumo Este artigo compara as características estruturais das substâncias húmicas aquáticas (SHA) com substâncias húmicas de turfa (SHT) usando diferentes técnicas analíticas, incluindo análise elementar, espectro de polarização cruzada de estado sólido 13C/ espectroscopia de ressonância magnética nuclear (13C CP-MAS RMN), espectroscopia no ultravioleta/visível e infravermelho com transformada de Fourier e carbono orgânico total (COT). As SHA foram extraídas de água coletada em um afluente do rio Itapanhaú (Bertioga/SP), utilizando resina XAD 8 e as SHT foram extraídas de turfa coletadas na margem do rio Mogi-Guaçu (Luis Antonio/SP) com uma solução de KOH. Após a diálise, ambos extratos de SHA e SHT foram filtrados em membrana com 0,45 m de tamanho de poro (Fração F1: < 0,45 m) e após fracionados através de ultrafiltração em diferentes tamanhos moleculares aparentes (F2: 100 kDa-0,45 m; F3: 30 - 100 kDa e F4: < 30 kDa). Os extratos de menor tamanho (F3 e F4) apresentaram um maior número de átomos de carbono alifáticos do que de carbonos aromáticos, uma maior concentração de grupos contendo oxigênio e uma percentagem mais elevada de ácidos fúlvicos do que os ácidos húmicos para ambas as frações de SHA e de SHT. No entanto, as SHA apresentaram maior quantidade de ácidos fúlvicos que ácidos húmicos em relação às SHT e propriedades estruturais distintas.

Abstract This paper compares the structural characteristics of aquatic humic substances (AHS) with humic substances from peat (HSP) through different analytical techniques, including elemental analysis, solid state 13C cross polarization/magic-angle-spinning nuclear magnetic resonance spectroscopy (13C CP-MAS NMR), ultraviolet/visible (UV/Vis) spectroscopy and Fourier transform infrared (FTIR) spectroscopy and total organic carbon (TOC). The AHS were extracted from water collected in a tributary of the Itapanhaú River (Bertioga/SP) using XAD 8 resin, and the HSP were extracted from peat collected in the Mogi Guaçu River bank (Luis Antonio/SP) with a KOH solution. After dialysis, both AHS and HSP extracts were filtered in membrane of 0.45 µm pore size (Fraction F1: < 0.45 µm) and fractioned by ultrafiltration in different apparent molecular sizes (AMS) (F2: 100 kDa-0.45 μm; F3: 30 kDa-100 kDa and F4: < 30 kDa). The extracts with the lowest AMS (F3 and F4) showed a higher number of aliphatic carbons than aromatic carbons, a higher concentration of groups containing oxygen and a higher percentage of fulvic acids (FA) than humic acids (HA) for both AHS and HSP. However, the AHS presented higher FA than HA content in relation to the HSP and distinct structural properties.

In this work, porous tubular scaffolds were prepared from a novel water soluble aldehyde-functionalized chitosan (ALDCHIT) hydrogel, which was obtained by dissolving this chitosan derivative in water and using oxidized dextrose (OXDEXT) as the crosslinking agent at different ALDCHIT:OXDEXT mole ratios (10:1, 10:2 and 10:4). By increasing the amount of OXDEXT in respect to ALDCHIT the hydrogels became more rigid and could absorb more than 200% of its weight in water. Since the ALDCHIT:OXDEXT 10:4 was the most stable hydrogel, its ability to form porous tubular scaffolds was investigated. The tubular scaffolds were prepared by the lyophilization method, where the orientation of the pores was controlled by exposing either the internal or the external surface of the frozen hydrogel during the sublimation step. When only the inner surface of the frozen hydrogel was exposed, tubular scaffolds with a highly porous lumen and a sealed outer surface were obtained, where the orientation of the pores, their sizes and interconnectivity seem to be optimum for vascular tissue engineering application.

RESUMO Objetivo Avaliação da ativação de fibras C para o registro de potenciais evocados utilizando-se laser de baixa potência, áreas pequenas de estimulação e escurecimento da pele. Método Potenciais evocados foram obtidos de 20 sujeitos. Uma placa de alumínio com uma pequena abertura foi acoplada à ponteira do laser para estimular área escurecida do dorso da mão. Resultados A intensidade média utilizada para estimulação foi de 70 ± 32 mW. Todos os sujeitos apresentaram respostas claras compreendendo dois picos um negativo (806 ± 61 ms) seguido por outro positivo (1033 ± 60 ms), correspondendo ao potencial evocado tardio por estimulação de fibras C. Conclusão Respostas de fibras C podem ser obtidas utilizando-se laser de baixa potência quando a estimulação é aplicada a pequenas áreas de pele escurecida. Esta estratégia oferece uma metodologia não invasiva que minimiza danos teciduais.

ABSTRACT Objective The evaluation of selective activation of C-fibers to record evoked potentials using the association of low-power diode laser (810 nm), tiny-area stimulation and skin-blackening. Method Laser-evoked potentials (LEPs) were obtained from 20 healthy young subjects. An aluminum plate with one thin hole was attached to the laser probe to provide tiny-area stimulation of the hand dorsum and the stimulated area was covered with black ink. Results The mean intensity used for eliciting the ultra-late laser-evoked potential (ULEP) was 70 ± 32 mW. All subjects showed a clear biphasic potential that comprised a negative peak (806 ± 61 ms) and a positive deflection (1033 ± 60 ms), corresponding to the ULEP related to C-fiber activation. Conclusion C-fiber-evoked responses can be obtained using a very low-power diode laser when stimulation is applied to tiny areas of darkened skin. This strategy offers a non-invasive and easy methodology that minimizes damage to the tissue.

This article presents a discussion on light diffraction by slits and grids as well as the development of an experimental apparatus which provides quantitative observation of the phenomenon. We conducted a brief historical survey on the evolution of the wave theory of light and the role of diffraction in the context of optical spectroscopy. We also reviewed the use of Huygens’ principle to calculate the intensity pattern obtained when light is diffracted by slits and compared the predictions with experimental results obtained using the apparatus developed. Finally, the use of the apparatus in an optical spectroscopy experiment was demonstrated.