Evolution of virtual learning environments in chemistry education

Visual information plays a central role in chemistry. The evolution of computational technologies in the last decade brought new opportunities to develop virtual learning chemistry environments to education that might change the ways of presenting and visualizing the chemistry knowledge. In this paper we present ten virtual learning environments related to chemistry teaching, and we compare them in terms of functionalities of visualization, virtual manipulation and possibility of creating new chemical structures

Comparação de Abordagens de Aprendizado de Máquina na Predição da Viscosidade para derivados de Poliacrilamida Parcialmente Hidrolisada

Partially hydrolyzed polyacrylamides (HPAM) are widely used to modulate the viscosity of formulations. The appropriate application of a viscosity model can facilitate the idealization of new macromolecules and contribute to a better understanding of the structure-property relationship. In the present study, machine learning approaches, Multiple Linear Regression (MLR) and Random Forest (RF), were compared to model the viscosifying effect of HPAM derivatives, based on their chemical composition and concentration in an aqueous solution. The evaluated data come from a previous experimental study, which explores a post-synthetic polymer modification methodology. The relative importance of the variables was investigated, determining the features with the greatest influence on viscosity, including variations in chemical composition, with emphasis on the more hydrophobic groups (C7 and C12). The accuracy of the models was evaluated using statistical criteria, the coefficient of determination (R2) and the Root Mean Square Error (RMSE). The Random Forest approach outperformed Multiple Linear Regression, with values of 0.97 and 0.30 for R2 and RMSE, respectively, compared to 0.83 and 0.67 for Multiple Linear Regression. Applying the Random Forest model, it was possible to generate a set of hypothetical macromolecules, with potential viscosifying effects. These macromolecules were idealized focusing on mixed compositions of C7 and C12 with a maximum structural variation of 10 mol%. Additionally, this structural mapping provided insights for designing promising polymers by inserting cyclic structures, such as CYCLOPROP, which could overcome the solubility limitation observed in the literature.Poliacrilamidas parcialmente hidrolisadas (HPAM) são amplamente utilizadas para modular a viscosidade de formulações. A aplicação adequada de um modelo de viscosidade pode facilitar a idealização de novas macromoléculas e contribuir para um melhor entendimento da relação estrutura-propriedade. No presente estudo, abordagens de aprendizado de máquina, Regressão Linear Múltipla (MLR) e Floresta Aleatória (RF), foram comparadas para modelar o efeito viscosificante de derivados HPAM, com base em sua composição química e concentração em uma solução aquosa. Os dados avaliados provêm de um estudo experimental anterior, que explora uma metodologia de modificação pós-sintética de polímeros. A importância relativa das variáveis foi investigada, determinando as características com maior influência na viscosidade, incluindo variações na composição química, com destaque para os grupos mais hidrofóbicos (C7 e C12). A acurácia dos modelos foi avaliada por meio de critérios estatísticos, coeficiente de determinação (R2) e Root Mean Square Error (RMSE). A abordagem Floresta Aleatória superou a Regressão Linear Múltipla, com valores de 0,97 e 0,30 para R2 e RMSE, respectivamente, em comparação com 0,83 e 0,67 para Regressão Linear Múltipla. Aplicando o modelo Floresta Aleatória, foi possível gerar um conjunto de macromoléculas hipotéticas, com potenciais efeitos viscosificantes. Esses polímeros foram idealizados com foco em composições mistas de C7 e C12, com variação estrutural máxima de 10 mol%. Adicionalmente, o mapeamento estrutural forneceu subsídios para o design de polímeros promissores através da inserção de estruturas cíclicas, como CYCLOPROP, o que pode superar a limitação de solubilidade observada na literatura

Co-creation design thinking process: learning with Demola approach

info:eu-repo/semantics/publishedVersio

Avaliação da ocorrencia de secas no município de Viçosa-MG, utilizando o índice de precipitação padronizada (SPI).

A metodologia do Índice de Precipitação Padronizada (SPI) foi testada e avaliada a ocorrência de eventos de seca no município de Viçosa-MG, nas escalas de tempo 3, 6 e 12 meses

Xanthenones: Calixarenes-catalyzed Syntheses, Anticancer Activity And Qsar Studies

An efficient method is proposed for obtaining tetrahydrobenzo[a]xanthene-11-ones and tetrahydro-[1,3]-dioxolo[4,5-b]xanthen-9-ones. The method is based on the use of p-sulfonic acid calix[n]arenes as catalysts under solvent-free conditions. The antiproliferative activity of fifty-nine xanthenones against six human cancer cells was studied. The capacity of all compounds to inhibit cancer cell growth was dependent on the histological origin of the cells. QSAR studies indicate that among compounds derived from β-naphthol the most efficient compounds against glioma (U251) and renal (NCI-H460) cancer cells are those having higher hydrogen bonding donor ability.131132803287Lozano, R., Naghavi, M., Foreman, K., (2013) Lancet, 380, pp. 2095-2128Nakash, O., Levav, I., Aguilar-Gaxiola, S., (2014) Psychooncology, 23, pp. 40-51Chabner, B.A., Roberts, J.T.G., (2005) Nat. Rev. Cancer, 5, pp. 65-72Lambert, R.W., Martin, J.A., Merrett, J.H., Parkes, K.E.B., Thomas, G.J., (1997) CT Int. ApplPoupelin, J.P., Saint-Rut, G., Fussard-Blanpin, O., Narcisse, G., Uchida-Ernouf, G., Lakroix, R., (1978) Eur. J. Med. Chem., 13, pp. 67-71Kumar, A., Sharma, S., Maurya, R.A., Sarkar, J., (2010) J. Comb. Chem., 12, pp. 20-24Hideo, T., Teruomi, J., (1981) Jpn. Patent, p. 56.005.480Banerjee, A., Mukherjee, A.K., (1981) Biotech. Histochem., 56, pp. 83-85Knight, C.G., Stephens, T., (1989) Biochem. J., 258, pp. 683-689Sirkencioglu, O., Talinli, N., Akar, A.J., (1995) Chem. Res., 12, p. 502Ion, R.M., Planner, A., Wiktorowicz, K., Frackowiak, D., (1998) Acta Biochim. Pol., 45, pp. 833-845Heravi, M.M., Alinejhad, H., Bakhtiari, K., Saeedi, M., Oskooie, H.A., Bamoharram, F.F., (2011) Bull. Chem. Soc. Ethiop., 25, pp. 399-406Khurana, J.M., Magoo, D.P., (2009) Tetrahedron Lett., 50, pp. 4777-4780Zhang, Z.-H., Wang, H.-J., Ren, X.-Q., Zhang, Y.-Y., (2009) Monatsh. Chem., 140, pp. 1481-1483Simões, J.B., Da Silva, D.L., De Fátima, A., Fernandes, S.A., (2012) Curr. Org. Chem., 16, pp. 949-971De Fátima, A., Fernandes, S.A., Sabino, A.A., (2009) Curr. Drug Discovery Technol., 6, pp. 151-170Varejão, E.V.V., De Fátima, A., Fernandes, S.A., (2013) Curr. Pharm. Des., 19, pp. 6507-6521Jose, P., Menon, S., (2007) Bioinorg. Chem. Appl., 28, pp. 1-16Da Silva, D.L., Fernandes, S.A., Sabino, A.A., De Fátima, A., (2011) Tetrahedron Lett., 52, pp. 6328-6330Simões, J.B., De Fátima, A., Sabino, A.A., Aquino, F.J.T., Da Silva, D.L., Barbosa, L.C.A., Fernandes, S.A., (2013) Org. Biomol. Chem., 11, pp. 5069-5073Simões, J.B., De Fátima, A., Sabino, A.A., Barbosa, L.C.A., Fernandes, S.A., (2014) RSC Adv., 4, pp. 18612-18615Shimizu, S., Shimada, N., Sasaki, Y., (2006) Green Chem., 8, pp. 608-614Fernandes, S.A., Natalino, R., Gazolla, P.A.R., Da Silva, M.J., Jham, G.N., (2012) Tetrahedron Lett., 53, pp. 1630-1633Monks, A., Scudeiro, D., Skehan, P., Shoemaker, R., Paull, K., Vistica, D., Hose, C., Boyd, M.J., (1991) J. Natl. Cancer Inst., 83, pp. 757-766Xia, B., Ma, W., Zheng, B., Zhang, X., Fan, B., (2008) Eur. J. Med. Chem., 43, pp. 1489-1498Stanton, D.T., Jurs, P.C., (1990) Anal. Chem., 62, p. 2323Stanton, D.T., Egolf, L.M., Jurs, P.C., Hicks, M.G., (1992) J. Chem. Inf. Comput. Sci., 32, p. 306Gutsche, C.D., Dhawan, B., No, K.H., Muthukrishnan, R., (1981) J. Am. Chem. Soc., 103, pp. 3782-3792Casnati, A., Ca, N.D., Sansone, F., Ugozzoli, F., Ungaro, R., (2004) Tetrahedron, 60, pp. 7869-7876Shinkai, S., Araki, K., Tsubaki, T., Some, T., Manabe, O., (1987) J. Chem. Soc., Perkin Trans. 1, pp. 2297-2299Da Silva, D.L., Reis, F.S., Muniz, D.R., Ruiz, A.L.T.G., De Carvalho, J.E., Sabino, A.A., Modolo, L.V., De Fátima, A., (2012) Bioorg. Med.Chem., 20, pp. 2645-2650Pacheco, S.R., Braga, T.C., Da Silva, D.L., Horta, L.P., Reis, F.S., Ruiz, A.L.T.G., De Carvalho, J.E., De Fátima, A., (2013) Med. Chem., 9, pp. 889-896Spartan'06, , Wavefunction, Inc., Irvine, CAStewart, J.J.P., (2007) MOPAC 2007, version 7, , 290 W Stewart Computational Chemistry, Colorado Springs, CODewar, M.J.S., Zoebisch, E.G., Healy, E.F., (1985) J. Am. Chem. Soc., 107, pp. 3902-3909Jensen, F., (2007) Introduction to computational chemistry, , John Wiley & Son Ltd, 2nd ednKatritsky, A.R., Lobanov, V.S., Karelson, M., (1996) CODESSA: Reference ManualVersion 2, , University of Florid

Brazilian strains of Toxoplasma gondii are controlled by azithromycin and modulate cytokine production in human placental explants

Background: Toxoplasma gondii is a protozoan parasite that causes congenital toxoplasmosis by transplacental transmission. Parasite strains are genetically diverse and disease severity is related to the genotype. In Uberlândia city, Brazil, two virulent strains were isolated: TgChBrUD1 and TgChBrUD2. Congenital toxoplasmosis is more prevalent in South America compared to Europe, and more often associated with severe symptoms, usually as a result of infection with atypical strains. Methods: Considering that T. gondii has shown high genetic diversity in Brazil, the effectiveness of traditional treatment may not be the same, as more virulent strains of atypical genotypes may predominate. Thus, the aim of this study were to evaluate the Brazilian strain infection rate in human villous explants and the azithromycin efficacy with regard to the control of these strains compared to traditional therapy. Villi were infected with RH, ME49, TgChBrUD1 or TgChBrUD2 strains and treated with azithromycin, spiramycin or a combination of pyrimethamine plus sulfadiazine. The villous viability was analyzed by LDH assay and morphological analysis. Parasite proliferation, as well as production of cytokines was analyzed by qPCR and ELISA, respectively. Statistical analysis was performed using the GraphPad Prism 5.0. Results: The treatments were not toxic and TgChBrUD1 infected villi showed a higher parasite burden compared with others strains. Treatments significantly reduced the intracellular proliferation of T. gondii, regardless of the strain. TgChBrUD1-infected villi produced a larger amount of MIF, IL-6 and TGF-β1 compared with other infected villi. Azithromycin treatment increased MIF production by RH- or TgChBrUD2-infected villi, but in ME49- or TgChBrUD1-infected villi, the MIF production was not altered by treatment. On the other hand, azithromycin treatment induced lower IL-6 production by ME49- or TgChBrUD1-infected villi. Conclusions: Azithromycin treatment was effective against T. gondii Brazilian strains compared with conventional treatment. Also, the TgChBrUD1 strain replicated more in villi and modulated important cytokines involved in parasite control, showing that different strains use different strategies to evade the host immune response and ensure their survival

Fermentation profile, aerobic stability, chemical and mineral composition of silages of mango combined with cocoa pod husk meal.

The objective was to evaluate the fermentation profile, aerobic stability, chemical composition, and mineral content of silages of mango combined with cocoa pod husk meal. A completely randomized design was adopted, including four levels (65, 70, 75, and 80%) and five repetitions, totaling 20 experimental silos that were opened after 90 days of sealing. Increasing mango levels in the silages increased the dry matter recovery, total carbohydrates, and fraction B2 of carbohydrates, and reduced gas losses, dry matter, and mineral matter. The quadratic effect was found for pH, buffering capacity, potassium, boron, iron, and nitrogen fractions A and B1 + B2. Using unconventional products such as mango combined with cocoa pod husk meal for silage making can reduce the cost of food supplementation for ruminants, and the environmental contamination

Licuri oil improves feedlot performance and modifies ruminal fauna of Santa Inês ewes.

The aim of this study was to evaluate the effect of inclusion of licuri oil on intake, digestibility, ingestive behavior, rumen protozoa population, and productive performance of Santa In?es ewe. Thirty-two Santa In?es ewe (multiparous, non-lactating, 2?4 years old and 36.7 ± 0.87 kg body weight) were distributed in a randomized block design, receiving diets containing licuri oil (0, 2, 4, and 5% based on total dry matter) in partial replacement of ground corn (n = 8 per treatment). The inclusion of licuri oil promoted a quadratic effect for the intakes of dry matter (P = 0.008), and neutral detergent fiber (P = 0.004), dry matter digestibility (P = 0.004), ether extract (P < 0.0001), average daily gain (P = 0.01), rumination time (min/day; P = 0.039 and min/g DM; P = 0.041), chewing time (min/g DM; P = 0.020), and for protozoa counts of the genus Entodinium (P < 0.0001). Ewe fed diets containing licuri oil showed higher consumption of ether extract (P < 0.0001), feed conversion (P = 0.004), and rumen pH (P < 0.0001), in contrast, a reduction in digestibility was observed neutral detergent fiber (P = 0.002) and total population of protozoa (P < 0.0001) in relation to those fed the control diet. In experimental conditions, it is possible to include licuri oil up to 2% in diets with 50% roughage offered to Santa In?es ewe to provide an increase in the intake and digestibility of dry matter and neutral detergent fiber, greater weight gain, and greater total protozoa count