934 resultados para antibacterial activities


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This article examines the participation of Spanish older people in formal, non-formal and informal learning activities and presents a profile of participants in each kind of learning activity. We used data from a nationally representative sample of Spanish people between 60 and 75 years old (n = 4,703). The data were extracted from the 2007 Encuesta sobre la Participación de la Población Adulta en Actividades de Aprendizaje (EADA, Survey on Adult Population Involvement in Learning Activities). Overall, only 22.8 % of the sample participated in a learning activity. However, there was wide variation in the participation rates for the different types of activity. Informal activities were far more common than formal ones. Multivariate logistic regression indicated that education level and involvement in social and cultural activities were associated with likelihood of participating, regardless of the type of learning activity. When these variables were taken into account, age did not predict decreasing participation, at least in non-formal and informal activities. Implications for further research, future trends and policies to promote older adult education are discussed.

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Fungi and bacteria are key agents in plant litter decomposition in freshwater ecosystems. However, the specific roles of these two groups and their interactions during the decomposition process are unclear. We compared the growth and patterns of degradativeenzymes expressed by communities of bacteria and fungi grown separately and in coexistence on Phragmites leaves. The two groups displayed both synergistic and antagonistic interactions. Bacteria grew better together with fungi than alone. In addition, there was a negative effect of bacteria on fungi, which appeared to be caused by suppression of fungal growth and biomass accrual rather than specifically affecting enzyme activity. Fungi growing alone had a high capacity for the decomposition of plant polymers such as lignin, cellulose, and hemicellulose. In contrast, enzyme activities were in general low when bacteria grew alone, and the activity of key enzymes in the degradation of lignin and cellulose (phenol oxidase and cellobiohydrolase) was undetectable in the bacteria-only treatment. Still, biomass-specific activities of most enzymes were higher in bacteria than in fungi. The low total activity and growth of bacteria in the absence of fungi in spite of apparent high enzymatic efficiency during the degradation of many substrates suggest that fungi provide the bacteria with resources that the bacteria were not able to acquire on their own, most probably intermediate decomposition products released by fungi that could be used by bacteria

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Chemical studies of the leaves of L. divaricata afforded 3beta-p-hydroxybenzoyl-tormentic acid, a triterpene with an ursene-type skeleton, a mixture whose main compound was an oleanene derivative, the maslinic acid, a C-glycoside flavone, vitexin and glucopyranosylsitosterol. A flavonoid, characterized as (-)-epicatechin, which belongs to the flavan-3-ol class, was isolated from the stem's bark. The structures of the compounds were elucidated by spectroscopic analysis. The antibacterial, antifungal and antiproliferative activities of the crude methanolic extracts of leaves and bark were evaluated and the antibacterial properties of the fractions of the barks were also investigated.

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Thiosemicarbazones are a class of compounds known by their chemical and biological properties, such as antitumor, antibacterial, antiviral and antiprotozoal activity. Their ability to form chelates with metals has great importance in their biological activities. Their synthesis is very simple, versatile and clean, usually giving high yields. They are largely employed as intermediates, in the synthesis of others compounds. This article is a survey of some of these characteristics showing their great importance to organic and medicinal chemistry.

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The purpose of this paper is to show the perceptions of the academic staff of classical languages (ancient Greek and Latin) concerning use of online activities during their courses. The study was carried out in three countries: Greece (three major Universities), Spain (University of Barcelona) and the United States (University of California, Berkeley) with the participation of thirty-three academic instructors. Depending on the level of use and acceptance of the ICT and following G. Moore¿s classification, we separated the participating academics in three groups: the conservatives, the mainstream and the early adopters. The fact that the smallest group is the third clearly shows the necessity for teachers¿ preparation and training before introducing innovative projects in the classroom. Since the starting point for the application of innovation in the classroom is the teacher, policy makers should focus on helping them become conscious of changes in teaching methods and include their opinion during the design of innovative projects.

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The purpose of this paper is to show the perceptions of the academic staff of classical languages (ancient Greek and Latin) concerning use of online activities during their courses. The study was carried out in three countries: Greece (three major Universities), Spain (University of Barcelona) and the United States (University of California, Berkeley) with the participation of thirty-three academic instructors. Depending on the level of use and acceptance of the ICT and following G. Moore¿s classification, we separated the participating academics in three groups: the conservatives, the mainstream and the early adopters. The fact that the smallest group is the third clearly shows the necessity for teachers¿ preparation and training before introducing innovative projects in the classroom. Since the starting point for the application of innovation in the classroom is the teacher, policy makers should focus on helping them become conscious of changes in teaching methods and include their opinion during the design of innovative projects.

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El auténtico protagonismo de los centros educativostiene que dirigirse a ayudar a pensar a sus alumnos y aenseñarlos a aprender, es decir, el docente tiene queenseñar estrategias de aprendizaje y debe promover elesfuerzo del estudiante para facilitar la construcción deesquemas y el aprendizaje permanente.El profesor debe utilizar cualquier situación deaprendizaje para enseñar dichas estrategias deaprendizaje, incluso en las situaciones de evaluación;por lo tanto, en este trabajo se sugiere que en lasevaluaciones de los alumnos y alumnas se tenga encuenta la metacognición como factor fundamental en elaprendizaje y la enseñanza

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The composition and biological activities of propolis, a resinous hive product collected by honeybees from various plant sources, depends on various factors such as season and vegetation of the area. The aim of this study was to evaluate the influence of the seasonal effect on the ethanolic extracts of Brazilian propolis (EEP) type 6 and type 12, collected during 6 months in terms of antibacterial activity and phenolic composition. The antimicrobial properties were evaluated by MIC and MBC on S. mutans Ingbritt 1600 and the profile of chemical composition by UV-visible spectrophotometry, HPLC-RF and GC-MS. The results demonstrated that the season in which propolis is collected influences its chemical composition, resulting in modifications in its antibacterial activity.

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The natural occurrence, biological activities and synthetic approaches to natural eight-, nine-, and eleven-membered lactones is reviewed. These medium ring lactones are grouped according to ring size, and their syntheses are discussed. The structures of some natural products early identified as medium-ring lactones were revised after total synthesis.

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The front end of innovation is regarded as one of the most important steps in building new software products or services, and the most significant benefits in software development can be achieved through improvements in the front end activities. Problems in the front end phase have an impact on customer dissatisfaction with delivered software, and on the effectiveness of the entire software development process. When these processes are improved, the likelihood of delivering high quality software and business success increases. This thesis highlights the challenges and problems related to the early phases of software development, and provides new methods and tools for improving performance in the front end activities of software development. The theoretical framework of this study comprises two fields of research. The first section belongs to the field of innovation management, and especially to the management of the early phases of the innovation process, i.e. the front end of innovation. The second section of the framework is closely linked to the processes of software engineering, especially to the early phases of the software development process, i.e. the practice of requirements engineering. Thus, this study extends the theoretical knowledge and discloses the differences and similarities in these two fields of research. In addition, this study opens up a new strand for academic discussion by connecting these research directions. Several qualitative business research methodologies have been utilized in the individual publications to solve the research questions. The theoretical and managerial contribution of the study can be divided into three areas: 1) processes and concepts, 2) challenges and development needs, and 3) means and methods for the front end activities of software development. First, the study discloses the difference and similarities between the concepts of the front end of innovation and requirements engineering, and proposes a new framework for managing the front end of the software innovation process, bringing business and innovation perspectives into software development. Furthermore, the study discloses managerial perceptions of the similarities and differences in the concept of the front end of innovation between the software industry and the traditional industrial sector. Second, the study highlights the challenges and development needs in the front end phase of software development, especially challenges in communication, such as linguistic problems, ineffective communication channels, a communication gap between users/customers and software developers, and participation of multiple persons in software development. Third, the study proposes new group methods for improving the front end activities of software development, especially customer need assessment, and the elicitation of software requirements.

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Decoction of roots of the Amazonian palm açaí (Euterpe precatoria Mart.) is widely used by Brazilian and Peruvian people as an anti-inflammatory, to heal kidney and liver diseases and against snake bites. In this study, the antioxidant activity of extracts and flavonoids (quercetin, catechin, epicatechin, rutin and astilbin) isolated from roots and leaf stalks of E. precatoria was investigated using β-carotene in TLC plates and DPPH radical scavenging in a spectrophotometric bioassay. All extracts and flavonoids showed activity. Also, the cytotoxic activity of these extracts was evaluated by the brine shrimp (Artemia salina) larvicide bioassay and was lower than that of lapachol, used as control. The presence of flavonoids and sitosterol-3-O-β-D-glucopyranoside in the extracts can justify the use of the plant in traditional medicine.

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Crude extract and fractions of Buddleja thyrsoides were investigated regarding antioxidant activities by DPPH, total phenolic contents by Folin-Ciocalteau and antimicrobial activity by the broth microdilution method. Total phenolics varied from 214.07 ± 3.6 to 438.4 ± 0.3 mg g-1. Crude extract, ethyl acetate, dichloromethane and butanolic fractions exhibited a weak scavenging activity (SC50=186.04 ± 10.8, 137.70 ± 8.5, 146.89 ± 9.0 and 165.71 ± 3.2 µg mL-1, respectively). A correlation between the antioxidant activities and total phenolic contents could be shown (r=0.857, p<0.01). The lowest value of MIC was observed with butanolic fraction against Saccharomyces cerevisiae (MIC and MFC at 62.5 µg mL-1). Dichloromethane and ethyl acetate fractions were effective against Staphylococcus aureus with MIC value at 250 and 500 µg mL-1 respectively.

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Propolis is mostly used as hydroalcoholic extract. Recently there has been a growing number of patents dealing with new solvents for preparing propolis extracts. This study aimed to prepare edible oil propolis extracts and compare their chemical composition and biological activity with ethanolic propolis extracts. ESI-MS and spectrophotometric methods were used for qualitative and quantitative analyses, respectively. Antibacterial activity was evaluated by diffusion in agar. Cytotoxicity was tested by MTT assay using tumor cell lines. The oil is able to extract bioactive compounds from propolis. Further studies are needed to improve extraction efficiency and to characterize the active components.

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Sidastrum paniculatum (L.) Fryxell belongs to the family Malvaceae and is popularly known as "malva roxa" or "malvavisco". The phytochemical study of the hexane, CHCl3 and EtOAc phases from the crude ethanol extract of S. paniculatum led to the isolation of six compounds: a mixture of β-sitosterol and stigmasterol, 4-methoxy-3-hydroxybenzoic acid, 4-methoxy-3-hydroxybenzaldehyde, N-trans-feruloyltyramine and kaempferol-3-O-β-D-(6''-E-p -coumaroyl) glucoside. The structural identification of the compounds was made on the basis of spectroscopic methods such as IR, ¹H and 13C NMR with the aid of including two-dimensional techniques, besides comparison with literature data. The β-sitosterol and stigmasterol mixture showed a significant anti-inflammatory activity.

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The antimycobacterial activity of 3-(4'-bromo[1,1'-biphenyl-4-yl)-3-(4-bromo-phenyl)-N,N-dimethyl-2-propen-1-amine (BBAP), free or incorporated in preformed liposomes, on extracellular M. tuberculosis H37Rv was 8 and 25 μM (MIC), respectively. Extracellular antimycobacterial activity was not significantly improved by entrapment of BBAP in liposomes, but there was a 6.1-fold reduction of BBAP cytotoxicity on J774 macrophages. Liposomal BBAP or its free form showed IC50 values of 165 and 27 μM, resulting in a selectivity index (SI=IC50/MIC) of 3.4 and 6.6, respectively. Free BBAP in concentrations from 10 to 80 μM were quite effective in eliminating intracellular M. tuberculosis while liposomal formulation was less effective at these concentrations.