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Effect of surface treatment on flexural strength and subcritical crack growth of lithium disilicate: an in vitro study
Full text linkAlternative surface treatments have been proposed for the cementation of lithium disilicate ceramics aiming to improve adhesive and flexural strength under fatigue. This study aimed to evaluate the slow crack growth (SCG) parameters of the lithium disilicate ceramic after hydrofluoric acid (HF) etching or air abrasion (AB) as surface treatments. Ceramic discs were treated with HF (5%, 20 s) or AB (30 µm silica-modified alumina particles, 2.8 bar, 10 mm distance, 15 s), and received a layer of resin cement. The surface roughness after surface treatment was evaluated (n = 5). Samples were tested in a piston-on-three-ball assembly to evaluate the flexural strength (n = 20), inert strength (n = 25), and to determine SCG parameters n and D (n = 35). The highest roughness (p < 0.01) was observed in the AB group, with the highest reliability according to the Weibull analysis, but the lowest SCG susceptibility. Flexural (p = 0.03) and inert strength (p < 0.01) were the greatest in the HF group. Despite exhibiting lower strength than 5% HF, air abrasion may be an alternative for the surface treatment of lithium disilicate surfaces, indicating the best prognosis over time
METABOLISMO EM MUDAS DE DENDEZEIRO SUBMETIDAS AO ALUMÍNIO
No full textDue to rainfall and high temperatures, the Amazonian soil undergoes changes in its source material and leaching of base cations. This results in deep, infertile, and acidic soil. Aluminum present in acidic soil impairs plant growth and development by inhibiting root formation, enzymatic reactions, absorption, transport, and nutrient utilization. This study aimed to evaluate the effects of aluminum dosage on the metabolism of the oil palm Elaeis guineensis Jacq. The study was conducted in a greenhouse at the Federal Rural University of Amazonia. The experimental design was randomized, with five replications, in which dosages of 0, 10, 20, 30, and 40 mg L-1 aluminum chloride (AlCl3.6H2O) were administered. Electrolyte leakage, nitrate, nitrate reductase, free ammonium, soluble amino acids, proline content, and soluble proteins were analyzed in the leaves and roots of the oil palm. The highest concentration of aluminum was found in the roots. AlCl3 treatment at 40 mg L-1 increased electrolyte leakage, nitrate, ammonium, and proline concentrations in the roots, and amino acid concentrations in both the leaves and roots. Furthermore, a decrease in nitrate reductase enzyme activity was observed in the roots. This study demonstrates that the oil palm has mechanisms of tolerance to aluminum toxicity.O presente trabalho teve como objetivo avaliar os efeitos da aplicação de dosagens de alumínio no metabolismo de Elaeis guineensis Jacq. O estudo foi conduzido em casa de vegetação no período de agosto de 2015 a janeiro de 2016. O delineamento experimental foi inteiramente casualizado, com 5 repetições, nas quais as dosagens de alumínio de 0, 10, 20, 30 e 40 mg L-1 de AlCl3 (AlCl3.6H2O). Observou-se que a maior concentração de alumínio foi encontrada nas raízes e os parâmetros bioquímicos analisados, verificou-se que a dosagem de 40 mg L-1 de AlCl3 aumentou o vazamento eletrolítico e maiores concentrações de NO3- e of NH4+ e prolina foram nas raízes, bem como maiores concentrações de aminoácidos nas folhas e raízes do dendê. Uma diminuição na atividade da enzima nitrato redutase foi observada nas raízes. O dendê apresentou mecanismos de tolerância à toxicidade do alumínio no período estudado e nas dosagens
Fabrication of 1,4-alpha-D-glucan glucanohydrolase holding Gel-Scaffolds using Agar-Agar, a natural polysaccharide and Polyacrylamide, a synthetic organic polymer for continuous liquefaction of starch
Full text link1,4-alpha-D-glucan glucanohydrolase is among the most widely used commercial hydrolytic enzymes acting randomly on the glycosidic linkages of starch resulting in its saccharification and liquefaction. Its applicability in different industries can be improved by enhancing its stability and reusability. Therefore, in the present study attempts have been made to enhance the industrial applicability of 1,4-alpha-D-glucan glucanohydrolase from Bacillus subtilis KIBGE-HAR by adapting immobilization technology. The study developed mechanically stable, enzyme containing gel-frameworks using two support matrices including agar-agar, a natural polysaccharide and polyacrylamide gel, a synthetic organic polymer. These catalytic gel-scaffolds were compared with each other in terms of kinetics and stability of entrapped 1,4-α-D-glucan glucanohydrolase. In case of polyacrylamide gel, Km value for immobilized enzyme increased to 7.95 mg/mL, while immobilization in agar-agar resulted in decreased Km value i.e 0.277 mg/mL as compared to free enzyme. It was found that immobilized enzyme showed maximum activity at 70 °C in both the supports as compared to free enzyme having maximum activity at 60 °C. Immobilized 1,4-α-D-glucan glucanohydrolase exhibited no change in optimal pH 7.0 before and after entrapment in polyacrylamide gel and agar-agar. The enzyme containing gel-scaffold was found suitable for repeated batches of starch liquefaction in industrial processes. Agar-agar entrapped 1,4-α-D-glucanglucanohydrolase was capable to degrade starch up to seven repeated operational cycles whereas polyacrylamide entrapped enzyme conserved its activity up to sixth operational cycle
Acute diarrheal diseases and their relationship with water quality in Araguatins, Tocantins, Brazil: a cross-sectional study
Full text linkDiarrhea remains a significant cause of death worldwide among children under five years old. In Brazil, the highest incidence of the disease occurs in the north region, and the epidemiological characteristics of diarrhea in Araguatins, TO, northern Brazil, have not been reported. The present study aimed to analyze the occurrence of acute diarrheal diseases (ADD) in Araguatins between 2014 and 2019 and its relationship with the quality of the public water supply. The study also analyzed the correlation between ADD frequency and rotavirus vaccination coverage of children. The data were obtained from the Brazilian Ministry of Health (SIVEP-DDA database) and the Health Surveillance Agency of Araguatins. The reported cases of acute diarrheal diseases significantly increased in 2018 and 2019 compared to the other years, and the occurrence of greater severity in the age group of ³10 years increased in the same period. The highest incidence of diarrhea occurred in 2018 when the application of rotavirus vaccines to children was the lowest. In most years investigated, the cases of acute diarrheal diseases occurred in both rainy and dry periods. However, in 2016, diarrhea cases were concentrated in the dry period, and Escherichia coli and total coliforms were found more frequently in the public water supply. The highest frequency of contamination with E. coli and total coliforms occurred in the Downtown area. The conclusion was that diarrheal disease may be caused, at least partially, by water-conveying agents in the treated public water supply of the Araguatins
ANÁLISE FATORIAL E ALFA DE CRONBACH NO ESTUDO DO CONHECIMENTO DE ADOLESCENTES ACERCA DO HIV/AIDS: VALIDAÇÃO DE CONSTRUTO
No full textTo analyze the efficacy and psychometric properties of the Knowledge, Attitudes, and Practices Questionnaire when applied to adolescents. It was a cross-sectional construct validation study. Ten questions on the knowledge of HIV/AIDS were selected from the questionnaire for further data analysis and applied to 623 adolescents attending high school. The Statistical Package for the Social Sciences (SPSS) 25.0™ and Stata 14.0 software processed the data. Cronbach\u27s Alpha verified the reliability of items, and the mean of each value ranged from 0.198 to 0.379. Factor analysis assessed the structure of correlations between variables. The resulting factors were lifestyle/habits, preventive actions, and endogenous and exogenous transmission. The scale was reliable for the studied population, ensuring the quality of the instrument.Objetivo: Analisar a eficácia e as propriedades psicométricas do Questionário de Saberes, Atitudes e Práticas em sua aplicação com adolescentes. Métodos: Tratou-se de um estudo transversal de validação de constructo. Foram selecionadas 10 perguntas do questionário supracitado, referentes ao conhecimento sobre HIV/aids, para posterior análise dos dados, o qual foi aplicado em 623 adolescentes que estavam cursando o ensino médio. O tratamento dos dados foi realizado no Statistical Package for the Social Sciences (SPSS) 25.0® e pelo Stata 14.0. Resultados: A confiabilidade dos itens foi averiguada por meio do Alfa de Cronbach, onde a média de cada valor variou de 0,198 a 0,379. Também foi realizada análise fatorial para analisar a estrutura das correlações entre as variáveis. Os fatores resultantes foram: Estilo de vida/hábitos, atitudes preventivas, formas de transmissão endógenas e formas de transmissão exógenas. Conclusão: Constatou-se a confiabilidade da escala na população estudada, assegurando a qualidade do instrumento
Allelopathy of Ricinus communis and light spectrum variation decrease emergence and growth of Cyperus rotundus
Full text linkWeeds negatively influence agricultural production. However, those losses depend on weed specie, its time of emergence, and period of interference on agricultural crops. Synthetic herbicides are commonly used to control these plants species; however, they may cause damage to the environment, human beings and animals health, and this problem justify the need to develop alternative bioherbicides. To evaluate the allelopathic potential of Ricinus communis (Castor bean) and light spectrum variation on the emergence and growth of Cyperus rotundus L., a trial was carried out in a protected environment with 15% of brightness reduction at the Center for Agricultural and Environmental Sciences at the Paraíba State University. Four aqueous extract concentrations of R. communis leaves were tested (0, 5, 10, and 15%) and four light spectrums variations (white, purple, blue, and red lights). Variables such as emergence, length, dry matter accumulation and growth rates of shoots and root of C. rotundus seedlings were assessed. Data were analyzed by normality test, analysis of variance, polynomial regression, and averages test. Soot and root emergence, length, and dry matter accumulation of C. rotundus seedlings were reduced due to the allelopathy caused by R. communis aqueous extract leaves (15% concentration) and under purple or red light spectrum radiation
Differential levels of soybean resistance to the whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) under controlled and uncontrolled environments are associated with plant age, damage intensity, and trichome density
Full text linkWhiteflies are a severe threat to soybean production in the tropics. This study aimed to evaluate the soybean resistance level of the whitefly Bemisia tabaci in controlled and uncontrolled environments that is associated with plant age, damage intensity, and trichome density. The research was conducted under two conditions: non-sprayed (NS) and sprayed (SP). This study used 50 soybean genotypes arranged in a randomized block design with three replicates. The whitefly population was derived from natural infestations. The results showed that the highest wild population of B. tabaci occurred at 40 days after planting (DAP), i.e., 126.08 adults/plant in the NS environment and 22.57 adults/plant in the SP environment. The peak damage intensity occurred at 50 DAP, 20.71% in the NS environment, and 17.15% in the SP environment. In the NS environment, there were six resistant genotypes (including the resistant control G100H), 25 moderate, and 19 susceptible genotypes. In the SP environment, 19 genotypes were resistant, 22 genotypes were moderate, and nine genotypes were susceptible, respectively. Six soybean genotypes showed consistent resistance to B. tabaci in NS and SP environments. The low density of leaf trichomes in soybean may influence the high resistance to B. tabaci. The resistant genotypes identified in this study could be utilized in breeding programs for B. tabaci resistance
Jian-Pi-Yi-Shen drug-containing serum promotes proliferation and activity of mouse osteoblasts
Full text linkJian-Pi-Yi-Shen (JPYS) decoction is a traditional Chinese herbal formula. The present study aimed to investigate the effect of JPYS drug-containing serum on the proliferation and activity of mouse osteoblasts. Sprague‒Dawley rats were fed JPYS decoction, calcium supplement, or normal saline for 6 weeks, and the serum was collected. Mouse osteoblasts were treated with JPYS drug-containing serum, calcium supplement serum, or blank control serum. Cell proliferation was assayed using thiazolyl blue tetrazolium bromide. Levels of alkaline phosphatase, nitric oxide, and nitric oxide synthase in the culture medium were measured. The JPYS drug-containing serum significantly improved the proliferation of osteoblasts compared to the blank control serum and the calcium supplement serum. It also significantly increased the levels of alkaline phosphatase in the culture medium compared to the blank control serum and the calcium supplement serum. Treatment with JPYS drug-containing serum for 48 h and 72 h significantly increased the nitric oxide (NO) concentration in the culture medium compared to the blank control serum. The NOS activity of the osteoblasts was significantly increased by JPYS drug-containing serum compared to blank control serum and calcium supplement serum. All these results were enhanced that the JPYS decoction promotes the proliferation and activity of mouse osteoblasts. These effects may be the underlying mechanisms of JPYS decoction in treating osteoporosis
Antimicrobial activity of comfort related properties of silk treated with herbal extracts in making of reusable masks
Full text linkThe study was aimed at divulging an eco-friendly antimicrobial finish on 100 % silk woven fabric. The leaves’ extract of Azadirachata indica, Butea monosperma and Litche chinensis were used as the development of eco-friendly antimicrobial finish. The antimicrobial property and comfort related property were checked before and after applying antimicrobial finish. In comfort related property absorbency & air permeability were checked. The ASTEM E2149 Shake Flask method was used to check antimicrobial finish and AATCC method was used for checking fabric property. One way ANOVA statistical test was applied for analysis of results. The FTIR and SEM results showed the presences of finish on fabrics. In comfort related property, absorbency and air permeability was increased. The results showed that antimicrobial finish made 100% reduction against microorganism up to 25 washes which can be used in making reusable masks fight against COVID- 19
Antifungal activity of Punica granatum linn extracts against Malassezia pachydermatis
Full text linkMalassezia pachydermatis causes external otitis, often affecting dogs, and control methods for this microorganism have been resistant to synthetic antifungals. Therefore, this study evaluated the antifungal activity of aqueous extracts of Punica granatum Linn (AEP) fruit peel dehydrated (AEPd) and in natura (AEPn) against Malassezia pachydermatis. The M. pachydermatis samples were from the Microbiology Laboratory of the State University of Northern Paraná (UENP), PR, Brazil. The strains were identified and replicated after inoculation in the Sabouraud dextrose medium. Subsequently, the P. granatum extract was obtained through different extraction methods: cold, water bath, decoction, and infusion. Each test was run fivefold at 10, 20, 30, 40, and 50% after 10, 20, and 30 minutes. The sensitivity of isolates was determined with the Kirby-Bauer disc diffusion method and indicated by an inhibition zone larger than 15 mm. The results were evaluated with a 2x3x6 factorial study design, ANOVA, and Tukey\u27s test at 5% significance. AEPn showed antifungal activity on M. pachydermatis strains, and AEPd did not present an inhibitory influence at any concentration and time. Extraction by decoction was the most efficient, followed by water bath, cold, and infusion. The extracts at a 50% concentration showed the best results, but all other doses determined an inhibition zone larger than 15 mm. Thus, AEP showed a significant therapeutic potential for controlling M. pachydermatis