Bentonite/polymer compound development to application in drilling fluids: Part 2

The most important bentonite clays sources are placed at Paraíba state, Brazil. These clays are largely used as viscosity agent in drilling fluids. Unfortunately for some kinds of available clay their parameters are far from PETROBRAS standard. Treatments based on polymeric addition consist on method to improve such parameters. In order to improve these parameters, this work proposes a methodology to develop bentonite/polymers compound for use in water based drilling fluids. Besides the raw clay others samples have been evaluated: i) one sample of a commercial bentonite; ii) two samples of carboximethyl cellullose (CMC) and iii) one sample of partially-hydrolyzed polyacrylamide (PAM). Based on experimental planning, ten compositions of polymeric compound (mix of two and three polymers) have been evaluated. For each composition of polymeric compound three different concentrations was added to clay. All experimental fluids have been evaluated accordingly with PETROBRAS standard to determine apparent and plastic viscosity, yield stress, and water loss. The results of the analysis show that by polymeric treatment of bentonite clay with compound polymeric allow to obtain a mixture with improved rheologic properties. Finally, this procedure allows to use low quality bentonite clays for drilling fluids application.Os depósitos de bentonita da Paraíba constituem um dos mais importantes do país. Essas argilas são empregadas, dentre outras aplicações, como viscosificante em fluidos de perfuração. Contudo, atualmente, alguns tipos de argila encontradas nesses depósitos não apresentam os parâmetros exigidos pela PETROBRAS e a aditivação polimérica surge como alternativa para adequar essas propriedades. Sendo assim, este trabalho objetiva o desenvolvimento de compostos bentonita/polímeros para uso em fluidos de perfuração à base de água. Para tanto, foram estudadas uma amostra de argila bentonítica sódica industrializada da Paraíba, Brasil, duas amostras de carboximetilcelulose (CMC) e uma amostra de poliacrilamida (PAM). O dimensionamento do composto polimérico (misturas de dois e três polímeros) foi elaborado por meio do planejamento experimental, sendo estudadas dez diferentes composições. Os compostos poliméricos, em três diferentes concentrações, foram misturados à argila seca. Em seguida, foram preparados os fluidos de perfuração e determinadas as viscosidades aparente e plástica, o limite de escoamento e o volume de filtrado de acordo com as normas da PETROBRAS. Os resultados das análises mostraram que a aditivação da bentonita com o composto polimérico permite obter uma mistura com melhores propriedades reológicas e de filtração. Finalmente, esse procedimento permite o uso de argilas bentoníticas de qualidade inferior em fluidos de perfuração de poços de petróleo.20921

Cellulose Nanocrystal Membranes as Excipients for Drug Delivery Systems

In this work, cellulose nanocrystals (CNCs) were obtained from flax fibers by an acid hydrolysis assisted by sonochemistry in order to reduce reaction times. The cavitation inducted during hydrolysis resulted in CNC with uniform shapes, and thus further pretreatments into the cellulose are not required. The obtained CNC exhibited a homogeneous morphology and high crystallinity, as well as typical values for surface charge. Additionally, CNC membranes were developed from CNC solution to evaluation as a drug delivery system by the incorporation of a model drug. The drug delivery studies were carried out using chlorhexidine (CHX) as a drug and the antimicrobial efficiency of the CNC membrane loaded with CHX was examined against Gram-positive bacteria Staphylococcus aureus (S. Aureus). The release of CHX from the CNC membranes is determined by UV-Vis. The obtaining methodology of the membranes proved to be simple, and these early studies showed a potential use in antibiotic drug delivery systems due to the release kinetics and the satisfactory antimicrobial activity.The authors would like to acknowledge the Department of Education, Universities and Investigation of the Basque Government (project IT1008-16), the Federal Agency for Support and Evaluation of Graduate Education (CAPES) through process BEX 8710/14-7, the Mexican Council of Science and Technology (CONACyT) through scholarship 216178 and theBrazilian National Council for Scientific and Technological Development for financial support through CNPq (# 482251/2013-1) for financially supporting this work. The authors also thank Maite Insausti and Oihane Arriortua for their kind help and support with Nanosizer and SGIker of the University of the Basque Country UPV/EHU for technical and human support provided with XRD, NMR and AFM characterizations and Altair Faes of the Regional Center of Oncology of the Federal University of Pelotas (UFPel) for the use of the equipment Eldorado 78

Analysis Of The Ergosterol Biosynthesis Pathway Cloning, Molecular Characterization And Phylogeny Of Lanosterol 14 α-demethylase (erg11) Gene Of Moniliophthora Perniciosa

The phytopathogenic fungus Moniliophthora perniciosa (Stahel) Aime & Philips-Mora, causal agent of witches’ broom disease of cocoa, causes countless damage to cocoa production in Brazil. Molecular studies have attempted to identify genes that play important roles in fungal survival and virulence. In this study, sequences deposited in the M. perniciosa Genome Sequencing Project database were analyzed to identify potential biological targets. For the first time, the ergosterol biosynthetic pathway in M. perniciosa was studied and the lanosterol 14α-demethylase gene (ERG11) that encodes the main enzyme of this pathway and is a target for fungicides was cloned, characterized molecularly and its phylogeny analyzed.ERG11 genomic DNA and cDNA were characterized and sequence analysis of the ERG11 protein identified highly conserved domains typical of this enzyme, such as SRS1, SRS4, EXXR and the heme-binding region (HBR). Comparison of the protein sequences and phylogenetic analysis revealed that the M. perniciosa enzyme was most closely related to that of Coprinopsis cinerea.374683693Aime, M.C., Phillips-Mora, W., The causal agents of witches’ broom and frost pod rot of cacao (chocolate, Theobroma cacao) from a new lineage of Marasmiaceae (2005) Mycologia, 97, pp. 1012-1022Albertini, C., Thebaud, G., Fournier, E., Leroux, P., Eburicol 14α-demethylase gene (CYP51) polymorphism and speciation in Botrytis cinerea (2002) Mycol Res, 106, pp. 1171-1178Altschul, S.F., Gish, W., Miller, W., Myersewand Lipman, D.J., Basic local alignment search tool (1990) J Mol Biol, 215, pp. 403-410Bak, S., Kahn, R.A., Oisen, C.E., Halkier, B.A., Cloning and expression in Escherichia coli of the obtusifoliol 14α-demethylase of Sorghum bicolor (L.) Moench, a cytochrome P450 orthologous to the sterol 14α demethylases (CYP51) from fungi and mammals (1997) Plant J, 11, pp. 191-201Barrett-Bee, K., Dixon, G., Ergosterol biosynthesis inhibition: A target for antifungal agents (1995) Acta Biochim Pol, 42, pp. 465-480Bellamine, A., Mangla, A.T., Nes, W.D., Waterman, M.R., Characterization and catalytic properties of the sterol 14α-demethylase from Mycobacterium tuberculosis (1999) Proc Natl Acad Sci USA, 96, pp. 8937-8942Butler, G., Rasmussen, M.D., Lin, M.F., Santos, M.A., Sakthikumar, S., Munro, C.A., Rheinbay, E., Reedy, J.L., Evolution of pathogenicity and sexual reproduction in eight Candida genomes (2009) Nature, 459, pp. 657-662Carrillo-Muñoz, A.J., Giusiano, G., Ezkurra, P.A., Quindós, G., Antifungal agents: Mode of action in yeast cells (2006) Rev Esp Quim, 19, pp. 130-139Ceita, G.O., Macedo, J.N., Santos, T.B., Alemanno, L., Gesteira, A.S., Micheli, F., Mariano, A.C., Meinhardt, L.W., Involvement of calcium oxalate degradation during programmed cell death in Theobroma cacao tissues triggered by the hemibiotrophic fungus Moniliophthora perniciosa (2007) Plant Sci, 173, pp. 106-117D’souza, C.A., Kronstad, J.W., Taylor, G., Warren, R., Yuen, M., Hu, G., Jung, W.H., Tangen, K., Genome variation in Cryptococcus gattii, an emerging pathogen of immunocompetent hosts (2011) MBio, 2, pp. e00342-e00410Délye, C., Laigret, F., Corio-Costet, M.F., Cloning and sequence analysis of the eburicol 14α-demethylase gene of the obligate biotrophic grape powdery mildew fungus (1997) Gene, 195, pp. 29-33Dujon, B., Sherman, D., Fischer, G., Durrens, P., Casaregola, S., Lafontaine, I., De Montigny, J., Talla, E., Genome evolution in yeasts (2004) Nature, 430, pp. 35-44Evans, H.C., Cacao diseases - The trilogy revisited (2007) Phytopathology, 97, pp. 1640-1643Felsenstein, J., Confidence limits on phylogenies: An approach using the bootstrap (1985) Evolution, 39, pp. 783-791Formighieri, E.F., Tiburcio, R.A., Armas, E.D., Medrano, F.J., Shimo, H., Carels, N., GóEs Neto, A., Sardinha-Pinto, N., The mitochondrial genome of the phytopathogenic basidiomycete Moniliophthora perniciosa is 109 kb in size and contains a stable integrated plasmid (2008) Mycol Res, 112, pp. 1136-1152Gasteiger, E., Hoogland, C., Gattiker, A., Duvaud, S., Wilkins, M.R., Appel, R.D., Bairoch, A., Protein identification and analysis tools on the ExPASy Server (2005) The Proteomics and Protocols Handbook, pp. 571-607. , In: Walker JM, Humana Press, TotowaGoffeau, A., Barrell, B.G., Bussey, H., Davis, R.W., Dujon, B., Feldmann, H., Galibert, F., Johnston, M., Life with 6000 genes (1996) Science, 265, pp. 2077-2082Griffith, G.W., Bravo-Velasquez, E., Wilson, F.J., Lewis, D.M., Hedger, J.N., Autecology and evolution of the witches’ broom pathogen (Crinipellis perniciosa) of cocoa (1994) The Ecology of Plant Pathogens, pp. 245-265. , In: Blakeman JP and Williamson B, CAB International, WallingfordGriffith, G.W., Nicholson, J., Neinninger, A., Birch, R., Witches’ brooms and frosty pods: Two major pathogens of cacao (2003) New Zeal J Bot, 41, pp. 423-435Hall, T.A., BioEdit: A user-friendly biological sequence alignment editor and analysis program for Windows 95/98/NT (1999) Nucleic Acids Res, 41, pp. 95-98Hof, H., Critical annotations to the use of azole antifungals for plant protection (2001) Antimicrob Agents Chemother, 45, pp. 2987-2990Jackson, C.J., Lamb, D.C., Marczylo, T.H., Parker, J.E., Manning, N.L., Kelly, D.E., Kelly, S.L., Conservation and cloning of CYP51: A sterol 14α-demethylase from Mycobacterium smegmatis (2003) Biochem Biophys Res Commun, 301, pp. 558-563James, T.Y., Kauff, F., Schoch, C.L., Matheny, P.B., Hofstetter, V., Cox, C.J., Celio, G., Miadlikowska, J., Reconstructing the early evolution of Fungi using a six-gene phylogeny (2006) Nature, 19, pp. 818-822Jones, T., Federspiel, N.A., Chibana, H., Dungan, J., Kalman, S., Magee, B.B., Newport, G., Magee, P.T., The diploid genome sequence of Candida albicans (2004) Proc Natl Acad Sci USA, 101, pp. 7329-7334Kairuz, P.B., Zuber, J.P., Jaunin, P., Buchman, T.G., Bille, J., Rossier, M., Rapid detection and identification of Candida albicans and Torulopsis (Candida) glabrata in clinical specimens by species-specific nested PCR amplification of a cytochrome P-450 lanosterol-α-demethylase (L1A1) gene fragment (1994) J Clin Microbiol, 32, pp. 1902-1907Kalb, V.F., Woods, C.W., Turi, T.G., Dey, C.R., Sutter, T.R., Loper, J.C., Primary structure of the P450 lanosterol demethylase gene from Saccharomyces cerevisiae (1987) DNA, 6, pp. 529-537Kall, L., Krogh, A., Sonnhammer, E.L., Advantages of combined transmembrane topology and signal peptide prediction- the Phobius web server (2007) Nucleic Acids Res 35:429-, p. 432Kim, D., Lim, Y.R., Ohk, S.O., Kim, B.J., Chun, Y.J., Functional expression and characterization of CYP51 from dandruffcausing Malassezia globosa (2011) FEMS Yeast Res, 11, pp. 80-87Lai, M.H., Kirsch, D.R., Nucleotide sequence of cytochrome P450 L1A1 (lanosterol 14α-demethylase) from Candida albicans (1989) Nucleic Acids Res, 17, p. 804Lamb, D.C., Kelly, D.E., Manning, N.M., Hollomon, D.W., Kelly, S.L., Expression, purification, reconstitution and inhibition of Ustilago maydis sterol 14α-demethylase (CYP 51P450) (1998) FEMS Microbiol Lett, 169, pp. 369-373Lee, C.H., Hsu, K.H., Wang, S.Y., Chang, T.T., Chu, F.H., Shaw, J.F., Cloning and characterization of the lanosterol 14α-demethylase gene from Antrodia cinnamomea (2010) J Agr Food Chem, 58, pp. 4800-4807Lees, N.D., Skaggs, B., Kirsch DR and BirdM(1995) Cloning of the late genes in the ergosterol biosynthetic pathway of Saccharomyces cerevisiae - A review Lipids, 30, pp. 221-226Lepesheva, G.I., Waterman, M.R., Sterol 14α-demethylase cytochrome P450 (CYP51), a P450 in all biological kingdoms (2007) Biochim Biophys Acta, 3, pp. 467-477Luo, C.X., Schnabel, G., The cytochrome P450 lanosterol 14α-demethylase gene is a demethylation inhibitor fungicide resistance determinant in Monilia fructicola field isolates from Georgia (2008) Appl Environ Microb, 74, pp. 359-366Martin, F., Aerts, A., Ahrén, D., Brun, A., Danchin, E.G., Duchaussoy, F., Gibon, J., Pereda, V., The genome of Laccaria bicolor provides insights into mycorrhizal symbiosis (2008) Nature, 452, pp. 88-92McQuilken, M.P., Rudgard, S.A., Sensitivity of Crinipellis periciosa to two triazole fungicides in vitro and their effect on development of the fungus in cocoa (1988) Plant Pathol, 37, pp. 499-506Meinhardt, L.W., Bellato, C.M., Rincones, J., Azevedo, R.A., Cascardo, J.C.M., Pereira, G.A.G., In vitro production of biotrophic- like cultures of Crinipellis perniciosa, the causal agent of Witches’ broom disease of Theobroma cacao (2006) Curr Microbiol, 52, pp. 191-196Mellado, E., Guerra, T.M.D., Estrela, M.C., Tudela, J.L.R., Identification of two different 14α-sterol demethylase related genes (cyp51A and cyp51B) in Aspergillus fumigatus and other Aspergillus species (2001) J Clin Microbiol 39:2431-, p. 2438Mondego, J.M.C., Carazzolle, M.F., Costa, G.G.L., Formighieri, E.F., Parizzi, L.P., Rincones, J., Cotomacci, C., Carrer, H., A genome survey of Moniliophthora perniciosa gives new insights into Witches’ broom disease of cacao (2008) BMC Genomics, 9, pp. 1-25Morales, I.J., Vohra, P.K., Puri, V., Kottom, T.J., Limper, A.H., Thomas, C.F., Characterization of a lanosterol 14α demethylase from Pneumocystis carinii (2003) Am J Resp Cell Mol, 29, pp. 232-238Mota, S.G.R., Barros, T.F., Castilho, M.S., In vitro screening and chemometrics analysis on a series of azole derivativeswith fungicide activity against Moniliophthora perniciosa (2010) J Braz Chem Soc, 21, pp. 510-519Nierman, W.C., Pain, A., Anderson, M.J., Wortman, J.R., Kim, H.S., Arroyo, J., Berriman, M., Bermejo, C., Genomic sequence of the pathogenic and allergenic filamentous fungus Aspergillus fumigatus (2005) Nature, 438, pp. 1151-1156Page, R.D.M., TREEVIEW: An application to display phylogenetic trees on personal computers (1996) Comput Appl Biosci, 12, pp. 357-358Park, H.G., Lee, I.S., Chun, Y.J., Yun, C.H., Johnston, J.B., Montellano, P.R.O., Kim, D., Heterologous expression and characterization of the sterol 14α-demethylase CYP51F from Candida albicans (2011) Arch Biochem Biophys, 509, pp. 9-15Pereira, J.L., Ram, A., Figueiredo, J.M., Almeida, L.C.C., Primeira ocorrência de vassoura-de-bruxa na principal região produtora de cacau do Brasil (1989) Agrotrópica, 1, pp. 79-81Petersen, T.N., Brunak, S., Heijne, G., Nielsen, H., SignalIP 4.0: Discriminating signal peptides from transmembrane regions (2011) Nat Methods, 10, pp. 785-786Pietila, M.P., Vohra, P.K., Sanyat, B., Wengenack, N.L., Raghavakaimal, S., Thomas, C.F., Cloning and characterization of CYP51 from Mycobacterium avium (2006) Am J Resp Cell Mol, 35, pp. 236-240Pires, A.B.L., Gramacho, K.P., Silva, D.C., Góes-Neto, A., Silva, M.M., Muniz-Sobrinho, J.S., Porto, R.F., Cascardo, J.C.M., Early development of Moniliophthora 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NOVO ALGORITMO BASEADO NO USO DOS SLOTS PARA DEFINIÇÃO DE ROTEAMENTO NAS REDES ÓPTICAS ELÁSTICAS

Neste artigo é proposto um novo algoritmo para melhorar o desempenho do roteamento nas redes ópticas elásticas. O algoritmo busca a rota que utiliza uma métrica para a escolha das rotas de menores caminhos, utilizando a quantidade de slots ocupados e o total de slots nos enlaces para a escolha da rota. O algoritmo aqui proposto é comparado com o algoritmo Melhor entre as Menores Rotas com Decisão por Similaridade (MMRDS) que escolhe a rota com mais enlaces em comum e ao algoritmo que utiliza o Sistema Fuzzy que infere um grau de pertinência na qualidade da rota. O algoritmo proposto apresentou uma taxa de bloqueio de circuito inferior de 4.02% e 8.2% e, 73.40% e 39.42%, comparados aos algoritmos MMRDS e ao sistema fuzzy [9] para as topologias NSFNET e USA, respectivamente. Além disso, foram analisadas outras métricas como a probabilidade de bloqueio por banda e utilização do espectro