859 resultados para instructional activities
Resumo:
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.
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This work reviews the current literature about the chemical constituents and the biological activities of the subtribe Lychnophorinae (Vernonieae, Asteraceae). The notable secondary metabolites are sesquiterpene lactones of furanoheliangolide (goyazensolide and eremantholide types) and flavonoids. Some of its most investigated activities include its anti-inflammatory, analgesic, antimicrobial and cytotoxic activities, specially for the Lychnophora and Eremanthus species. The data presented on this paper not only displayed the role played by the Lychnophorinae species as a source of bioactive compounds, but also reinforced the need of further studies involving the species of such subtribe.
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This work describes the phytochemical study of stems of Mimosa invisa (Mimosaceae) and the evaluation of the antioxidant potential of isolated compounds. Cromatografic techniques were employed to isolate salicifoliol, pinoresinol, quercetin, quercetin-3-O-rhamnopyranosyl, quercetin-3-O-arabinofuranosyl lupeol, β-amyrin, sitosterol, p-hydroxy coumaric acid, 4-hydroxy-3-methoxy benzaldehyde (vanillin), 4-hydroxy-3,5-dimethoxy benzaldehyde, 4-hydroxy-3-methoxy benzoic acid and 4',6,7- trimethoxy flavonol. The latter had been previously described but the spectrometric data shown indicated the structure required review. The antioxidant activity of the compounds was evaluated by the DPPH test and capability of NBT reduction by superoxide radicals. Quercetin glycosides showed lower antioxidant potential than quercetin and, salicifoliol was found to be more active than pinoresinol.
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A new series of 5-benzylidene-2-[(pyridine-4-ylmethylene)hydrazono]-thiazolidin-4-ones 4a-l have been synthesized. These compounds were designed by a molecular hybridization approach. 2-[(Pyridine-4-ylmethylene)hydrazono]-thiazolidin-4-ones 3a-d were also obtained and used as intermediates to give the target compounds. The in vitro antimicrobial and cytotoxic activities were evaluated for both series. The intermediate 3b showed considerable antibiotic activity against B. subtilis and C. albicans. In the cytotoxic activity compounds 3b (IC50= 4.25 ± 0.36 µg/mL) and 4l (IC50= 1.38 ± 0.04 µg/mL) were effective for inhibition of human erythromyeloblastoid leukemia (K-562) and human lung carcinoma (NCI-H292) cell lines, respectively.
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This manuscript describes an update review with up to 285 references concerning the occurrence of amides from a variety of species of the genus Piper (Piperaceae). Besides addressing occurrence, this review also describes the biological activities attributed to extracts and pure compounds, a compiled 13C NMR data set, the main correlations between structural and NMR spectroscopic data of these compounds, and employment of hyphened techniques such as LC-MS, GC-MS and NMR for analysis of amides from biological samples and crude Piper extracts.
Resumo:
Chromatographic analysis of flavonoids in ethyl acetate fractions of the stamen, gynoecium, and petal of Magnolia grandiflora L. by HPLC-PDA-MS/MS-ESI in the negative ionization mode was performed in this study. The results revealed the presence of eight flavonoids: apigenin 8-C-glucoside, luteolin 8-C-glucoside, quercetin 3-O-rutinoside, quercetin 3-O-galactoside, quercetin, 3-O-glucoside, kaempferol 3-O-rutinoside, isorhamnetin 3-O-glucoside, and isorhamnetin. Their quantification revealed that luteolin 8-C-glucoside is the major flavonoid and that the total phenolic content is concentrated primarily in the stamen. The antioxidant and hepatoprotective effects of ethanolic extract of the flower organs were evaluated against hepatotoxicity induced by CCl4, compared with the effects of silymarin.
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A facile one-step synthesis of 1H-benzoxazine-2,4-diones from heterocyclic anhydrides and TMSA was described. This paper determines their antimicrobial activity against nine human bacterial pathogens by the broth microdilution method; antioxidant activity by DPPH• inactivation and a ferric-reducing power assay; and toxicity by a brine shrimp, Artemia salina, assay. The 1H-benzoxazine-2,4-dione yields were in the range of 57 to 98%. The novel compound 1H-pyrazino[2,3-][1,3]oxazine-2,4-dione 4c showed the highest antioxidant capacity (DPPH 35.4% and FRAP 0.063 µmol TEs/µmol).
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Stemodinol, a new natural compound, together with known compounds including jaceidin, stemodin, stemodinoside B, isocrenatoside, verbascoside, crenatoside, and isoverbascoside, were isolated from Stemodia maritima Linn. The antioxidant (DPPH method) and antimicrobial activities of stemodin, stemodinoside B, and crenatoside were investigated. Among the components tested, only crenatoside isolated from the roots showed a high antioxidant power. Stemodin and stemodinoside B exhibited antibacterial activities.
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Chemical investigation of Guettarda viburnoides (leaves) led to the isolation of ursolic acid, uncaric acid, secoxyloganin, and grandifloroside, along with a mixture of quercetin-3-O-β-D-galactopyranoside and quercetin-3-O-β-D-glucopyranoside, and of β-sitosterol and stigmasterol. The structures of the isolated compounds were elucidated on the basis of their NMR data. The crude extract, ethyl acetate fraction, aqueous-methanol fraction, and grandifloroside showed significant DPPH free-radical scavenging activities with IC50 ranging from 18.92 to 26.47 µg mL-1. The topical administration of the crude extract and fractions markedly reduced the croton oil-induced mice ear edema in 67.0%-99.0%. Inhibition of tissue MPO activity was also observed, which demonstrated an anti-inflammatory effect of the G. viburnoides species.
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Blogs and other technology tools are commonly used in our society. Although we are familiar with the use of technology for social interaction, its application in the classroom environment is still not fully appreciated by the teaching community as a useful learning tool. This paper sheds light on this use by presenting the analysis of the comments posted on a blog used by undergraduate chemistry students for a scientific communication undergraduate course. On the course, students used the blog to ask questions and discuss assignments. All the comments were monitored by the professor and her teaching assistant, who also posted their comments. We analyzed the content of these comments using the model proposed by Henri and adapted by McKenzie and Murphy. The results show a predominance of administrative comments, followed by course content comments. The findings also indicated that this tool complements classroom discussions, supports the participation of students who would otherwise not take part, and allows a continuous learning process for all the students. We concluded that the use of blogs improved the classroom experience and supported the instructional classroom activities.
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Hormonstörande ämnen är syntetiska eller naturliga ämnen som stör organismers hormonsystem och bidrar till könsförvirring och sterilitet. Sådana ämnen kommer i ökande takt ut i vattenmiljön genom rester av läkemedel, bekämpningsmedel och industriprodukter. Eftersom det finns många likheter mellan hormonsystemen hos människan och övriga ryggradsdjur kan till exempel fiskar användas som modellsystem för att underöka detta problem. I tidigare undersökningar har man funnit hormonella störningar, bl.a. feminisering och maskulinisering hos fiskar som utsatts för avfallsvatten från kommunala reningsverk eller avfallsvatten från pappersindustrin. Målet med denna avhandling var att undersöka om renat avfallsvatten från kommunala reningsverk längs Finlands kust innehåller hormonstörande ämnen i sådana mängder att de kan försorsaka hormonstörande effekter på fisk. Målet i denna avhandling var också att utveckla cellulära testsystem baserade på fiskceller, eftersom behovet av tillförlitliga och kostnadseffektiva cellbaserade tester för att underlätta riskbedömningen av hormonstörande ämnen är mycket stort för tillfället. Som testsystem har storspiggen använts, som besitter flera användbara biomarkörer för att mäta hormonstörande ämnens påverkan. Resultaten tyder på att problemen med hormonstörande påverkan på fisk inte är lika utbredda i Finland som i många andra europeiska länder. Detta beror troligtvis på att finska reningsverk har effektiva reningstekniker som reducerar mängden hormonstörande ämnen, eller på att utspädningen av avloppen i recipienterna är större än i många andra länder. Dock kan problemen inte helt uteslutas eftersom vissa feminiserande (estrogena) effekter kunde observeras hos fisken i de undersökta recipienterna utanför kommunala reningsverk. I kontrollerade laboratorieförsök där storpsiggar exponerades för kommunalt avloppsvatten uppmättes även här effekter som tyder på förekomst av estrogener i avloppsvattnet. De cell-baserade testsystemen klarade av att förutspå hormonella effekter hos hel fisk och kan därför vara mycket användbara i fortsatta studier av hormonstörande ämnens verkningsmekanismer i preliminära toxicitetsbedömningar.
Resumo:
ABSTRACTThis study presents a contribution to the modeling of a computer application employing a method of serviceability performance for unpaved roads, aiming the management of maintenance/restoration activities of the primary surface layer. The proposed methodology consisted of field inspections during dry (April to September) and rainy (October to March) periods, during which objective evaluations were performed to survey of defects and their densities and degrees of severity. To aid the functional classification of analyzed road sections and the determination of the defect with major influence on the serviceability of these roads, the method of serviceability performance proposed by Silva (2009)was implemented in the Visual Basic for Applications (VBA) language in Microsoft Excel software. With the use of the computer application proposed it was possible to identify among the defects analyzed in field, through the index of serviceability of the sampling unit per defect type (ISUdef), which one had the greatest influence on determining the relative serviceability index per road section (IST). The results allow us to conclude that the computer application Road achieved satisfactory results, since the objective evaluation criteria applied to road sections denotes consistency regarding their serviceability.
Resumo:
Prerequisites and effects of proactive and preventive psycho-social student welfare activities in Finnish preschool and elementary school were of interest in the present thesis. So far, Finnish student welfare work has mainly focused on interventions and individuals, and the voluminous possibilities to enhance well-being of all students as a part of everyday school work have not been fully exploited. Consequently, in this thesis three goals were set: (1) To present concrete examples of proactive and preventive psycho-social student welfare activities in Finnish basic education; (2) To investigate measurable positive effects of proactive and preventive activities; and (3) To investigate implementation of proactive and preventive activities in ecological contexts. Two prominent phenomena in preschool and elementary school years—transition to formal schooling and school bullying—were chosen as examples of critical situations that are appropriate targets for proactive and preventive psycho-social student welfare activities. Until lately, the procedures concerning both school transitions and school bullying have been rather problem-focused and reactive in nature. Theoretically, we lean on the bioecological model of development by Bronfenbrenner and Morris with concentric micro-, meso-, exo- and macrosystems. Data were drawn from two large-scale research projects, the longitudinal First Steps Study: Interactive Learning in the Child–Parent– Teacher Triangle, and the Evaluation Study of the National Antibullying Program KiVa. In Study I, we found that the academic skills of children from preschool–elementary school pairs that implemented several supportive activities during the preschool year developed more quickly from preschool to Grade 1 compared with the skills of children from pairs that used fewer practices. In Study II, we focused on possible effects of proactive and preventive actions on teachers and found that participation in the KiVa antibullying program influenced teachers‘ self-evaluated competence to tackle bullying. In Studies III and IV, we investigated factors that affect implementation rate of these proactive and preventive actions. In Study III, we found that principal‘s commitment and support for antibullying work has a clear-cut positive effect on implementation adherence of student lessons of the KiVa antibullying program. The more teachers experience support for and commitment to anti-bullying work from their principal, the more they report having covered KiVa student lessons and topics. In Study IV, we wanted to find out why some schools implement several useful and inexpensive transition practices, whereas other schools use only a few of them. We were interested in broadening the scope and looking at local-level (exosystem) qualities, and, in fact, the local-level activities and guidelines, along with teacherreported importance of the transition practices, were the only factors significantly associated with the implementation rate of transition practices between elementary schools and partner preschools. Teacher- and school-level factors available in this study turned out to be mostly not significant. To summarize, the results confirm that school-based promotion and prevention activities may have beneficial effects not only on students but also on teachers. Second, various top-down processes, such as engagement at the level of elementary school principals or local administration may enhance implementation of these beneficial activities. The main message is that when aiming to support the lives of children the primary focus should be on adults. In future, promotion of psychosocial well-being and the intrinsic value of inter- and intrapersonal skills need to be strengthened in the Finnish educational systems. Future research efforts in student welfare and school psychology, as well as focused training for psychologists in educational contexts, should be encouraged in the departments of psychology and education in Finnish universities. Moreover, a specific research centre for school health and well-being should be established.