943 research outputs found

    Empleo de carbones activados procedentes de lignina como catalizadores no metálicos en la oxidación húmeda con peróxido de hidrogeno

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    Una lignina obtenida por un proceso a la sosa se empleó como precursor para preparar carbones activados. En primer lugar, se carbonizó la lignina en atmósfera inerte y, a continuación, se procedió a su activación térmica en atmósfera oxidante usando temperaturas entre 150 y 350 C. Se emplearon distintas técnicas de caracterización para evaluar sus propiedades texturales y química superficial, observando un aumento del desarrollo de la porosidad con la temperatura de activación usada, y un marcado carácter básico en todos ellos. Los carbones preparados se ensayaron como catalizadores no metálicos para la oxidación húmeda catalítica con peróxido de hidrógeno (CWPO) de 4-nitrofenol (4-NP; 5 g L-1), usando condiciones de operación relativamente suaves (presión atmosférica, T = 50 C, pH = 3, carga de catalizador = 2.5 g L-1, [H2O2]0 = 17.8 g L-1). Con los catalizadores preparados a las temperaturas de activación más altas (300 y 350 C) se logró eliminar cerca del 70 % de 4-NP, observándose una eficiente descomposición de H2O2. Por su parte, los materiales preparados a las temperaturas de activación más bajas (150 y 200 C) promovieron una descomposición del H2O2 más rápida pero ineficiente, eliminándose menos del 25 % de 4-NP en estos casos.info:eu-repo/semantics/publishedVersio

    Tin determination in fistula seals from Conimbriga and Augusta Emerita

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    Understanding caretakers\u27 dilemma in deciding whether or not to adhere with referral advice after pre-referral treatment with rectal artesunate

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    Background: Malaria kills. A single rectal dose of artesunate before referral can reduce mortality and prevent permanent disability. However, the success of this intervention depends on caretakers\u27 adherence to referral advice for follow-up care. This paper explores the dilemma facing caretakers when they are in the process of deciding whether or not to transit their child to a health facility after pre-referral treatment with rectal artesunate. Methods: Four focus group discussions were held in each of three purposively selected villages in Mtwara rural district of Tanzania. Data were analysed manually using latent qualitative content analysis. Results: The theme «Caretakers dilemma in deciding whether or not to adhere with referral advice after pre-referral treatment with rectal artesunate» depicts the challenge they face. Caretakers\u27 understanding of the rationale for going to hospital after treatment - when and why they should adhere - influenced adherence. Caretakers, whose children did not improve, usually adhered to referral advice. If a child had noticeably improved with pre-referral treatment however, caretakers weighed whether they should proceed to the facility, balancing the child\u27s improved condition against other competing priorities, difficulties in reaching the health facilities, and the perceived quality of care at the health facility. Some misinterpretation were found regarding the urgency and rationale for adherence among some caretakers of children who improved which were attributed to be possibly due to their prior understanding. Conclusion: Some caretakers did not adhere when their children improved and some who adhered did so without understanding why they should proceed to the facility. Successful implementation of the rectal artesunate strategy depends upon effective communication regarding referral to clinic. © 2010 Simba et al; licensee BioMed Central Ltd

    Treatment of oily streams contaminated with lipophilic pollutants by peroxide oxidation using catalysts developed from compost derived from municipal solid waste

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    Nowadays, waste management through mechanical biological treatment (MTB) consists on the use of the separated organic fraction of municipal solid waste (MSW) to feed anaerobic digestion processes, resulting therein a solid stream, further processed to compost, which can be used in agriculture. Currently, the production of compost is higher when compared to its demand and expected developments on coming directives under “End-of-waste” criteria are leading to barriers on the use of fertilizers resulting from waste [1]. Within this context, the current work proposes an alternative strategy to the valorisation of compost, through the production of low-cost materials to be used in catalytic processes. Thus, several materials were prepared from compost obtained from a MTB plant for MSW. The compost was first mixed and washed with water, in order to homogenise and remove soluble compounds and suspend solids. Then, two different materials were prepared by carbonization at 400 (C-400) and 800 ºC (C-800). In addition, following the procedure previously described [2], two materials were prepared with H2SO4 before and after the carbonization at 800 ºC (C-S-800 and C-800-S, respectively). The materials were assessed in H2O2 decomposition and peroxide oxidation of three model pollutants with different lipophilic character, Sudan-IV (S-IV), 2-nitrophenol (2-NP) and 4nitrophenol (4-NP) in cyclohexane and water in order to simulate oily wastewater (Fig.1). The materials show catalytic activity in both H2O2 decomposition and peroxidation of the pollutants when compared to the non-catalytic runs. The most significant difference was found when C-800-S was used, since low conversions of H2O2 and 4-NP was achieved. However, the acidification of the sample resulted favourable in the oxidation of S-IV, leading to the highest conversion of this pollutant.This work is a result of projects: VALORCOMP, funded by FEDER through Programme INTERREG V A Spain - Portugal (POCTEP) 2014–2020; “AIProcMat@ N2020 - Advanced Industrial Processes and Materials for a Sustainable Northern Region of Portugal 2020”, with the reference NORTE-01-0145-FEDER-000006, supported by NORTE 2020, under the Portugal 2020 Partnership Agreement, through FEDER; and POCI-01-0145- FEDER-006984 – Associate Laboratory LSRE-LCM funded by FEDER through COMPETE2020 - POCI – and by national funds through FCT.info:eu-repo/semantics/publishedVersio

    The Use Of Various Strains Of Rhizobium Tropici For Inoculation Of Snap Bean Cultivars With A Determinate Growth Pattern

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    The snap bean (Phaseolus vulgaris L.) is an economically important vegetable in Brazil. Bean plants can establish symbiotic associations with bacteria that fix atmospheric nitrogen. These associations show specificity of host plants to certain bacteria. Nitrogen fertilization constitutes a crop production cost, and the use of Rhizobium inoculation to supply nitrogen to crops may decrease the production costs. The aim of this study was to evaluate the effects of inoculation of three different snap bean cultivars with three Rhizobium tropici strains on agronomical performance of the plant. A completely randomized experimental design was used, with a 3 × 5 factorial scheme and four replicates per treatment. The factors tested were three snap bean cultivars (UEL 1, Alessa, and UEL 2), and five types of inoculation (uninoculated control, inoculation with SEMIA 4077, SEMIA 4080, SEMIA 4088, or with a mix of the three strains). The experiment was conducted in a greenhouse. Plant height, stem diameter, pod length, the number of pods per plant, and average weight and yield of commercial-grade pods, were determined. An analysis of variance was conducted using the F test, followed by Tukey's test (p < 0.05). Inoculation had a positive effect on all the parameters quantified. The beneficial effect was more pronounced in plants inoculated with the mix of Rhizobium strains.3763965397

    Contaminación por Staphylococcus aureus en el procesamiento de un embutido fermentado português (linguiça)

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    Linguiça is a Portuguese dry-fermented sausage, which has been found to harbour food-borne pathogens in the past. Hence, the objective of this study was to investigate the levels of total viable counts (TVC), Enterobacteriaceae, and S. aureus at the key production stages of linguiça by depicting their changes using principal component analysis. Unlike Enterobacteriaceae counts, which decreased from raw meat to final product, S. aureus increased significantly in the meats throughout processing. While Enterobacteriaceae was very sensitive to the decrease in water activity, S. aureus remained viable and developed during fermentation. The presence of S. aureus at all stages should prompt industries to reinforce good hygiene practices in the processing of linguiça.Esta investigación se realizó dentro del proyecto PTDC/AGR-TEC/3107/2012, financiado por la Fundación Portuguesa de Ciencia y Tecnología (FCT)/Fondos Europeos de Desarrollo Regional (FEDER). La Dra. Gonzales-Barron agradece el apoyo financiero provisto por la FCT a través del programa "Investigator Fellowship" (IF/00570)info:eu-repo/semantics/publishedVersio

    Immunization with rP22 induces protective immunity against Schistosoma mansoni: Effects on granuloma down-modulation and cytokine production

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    AbstractSchistosomiasis remains a significant public health problem in tropical countries and it is recognized as the most important human helminth infection in terms of morbidity and mortality. Although the existing antischistosomal drugs are highly effective, they do not prevent against reinfection or granuloma formation. Therefore, vaccine strategies are essential for the control of schistosomiasis. Our group recently identified the recombinant (r) P22 protein, a component of the adult worm protein fraction PIII that has been shown to engender protective and immunomodulatory effects on murine schistosomiasis. A cDNA clone encoding rP22 was isolated from a Schistosoma mansoni adult worm cDNA library using anti-PIII rabbit serum; it exhibited complete identity with S. mansoni Sm21.7 EF-hand antigen. Confocal microscopy revealed that rP22 is a tegument protein localized on the surface of S. mansoni miracidia and adult worms. Mice immunized with rP22 exhibited a 51% and 22.5% decrease in adult worm burden and in hepatic eggs, respectively. Additionally, rP22 vaccine produced a reduction in 60% of liver granuloma size and 71% of fibrosis in mice, suggesting that rP22 might contribute to down-modulate granulomatous hypersensitivity to S. mansoni eggs. Protective immunity in mice was associated with high titers of rP22-specific IgG antibodies; elevated production of IFN-γ, TNF-α and IL-10; and a reduced level of IL-4. In conclusion, these findings indicate that rP22-based vaccines could be useful to elicit protection and reduce pathology associated to schistosomiasis

    Optical Density Of Bone Repair After Implantation Of Homogenous Demineralized Dentin Matrix In Diabetic Rabbits

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    This research evaluated the bone repair process after implantation of homogenous demineralized dentin matrix (HDDM) in surgical defects in the parietal bone of rabbits with alloxan-induced diabetes, using a polytetrafluorethylene (PTFe) barrier for guided bone regeneration. Thirty-six rabbits were used and divided into four groups: control (C, n = 12), diabetic (D, n = 12, left parietal bone), diabetic with PTFe (DPTFe, same 12 rabbits, right parietal bone), and diabetic with PTFe associated to HDDM (D-PTFe+HDDM, n = 12). Bone defects were created in the parietal bone of the rabbits and the experimental treatments were performed, where applicable. The rabbits were sacrificed after 15, 30, 60 and 90 days. The bone defects were examined radiographically and by optical density (ANOVA and Tukey test, p < .05). The radiographic findings showed that the D-PTFe+HDDM group presented greater radiopacity and better trabecular bone arrangement when compared to that of the C, D and D-PTFe groups. The statistical analysis showed significant differences in the optical density of the newly formed bone among the studied groups. It was possible to conclude that HDDM was biocompatible in diabetic rabbits.223275280Abreu, P.P., Morosolli, A., Araújo, M.M., Carvalho, V.A.P., Gomes, M.F., Effects of autogenous demineralized dentin matrix on dental socket wound healing process in human (2004) Braz Oral Res, 18, p. 52. , SupplCarvalho, V.A.P., Tosello, D.O., Salgado, M.A.C., Gomes, M.F., Histomorphometric analysis of homogenous demineralized dentin matrix as osteopromotive material in rabbit mandibules (2004) Int J Oral Maxillofac Implants, 19 (5), pp. 679-686Gomes, M.F., Anjos, M.J.S., Nogueira, T.O., Catanzaro-Guimarães, S.A., Autogenous demineralized dentin matrix for tissue engineering applications: Radiographic and histomorphometric studies (2002) Int J Oral Maxillofac Implants, 17 (4), pp. 488-497Gomes, M.F., Silva, M.J.S., Nogueira, T.O., Catanzaro-Guimarães, S.A., Histologic evaluation of the osteoinductive property of autogenous demineralized dentin matrix on surgical bone defects in rabbit skulls using human amniotic membrane for guided bone regeneration (2001) Int J Oral Maxillofac Implants, 16 (4), pp. 563-571Guyton, A.C., Hall, J.E., (2006) Insulin, Glucagon, and Diabetes mellitus, pp. 827-840. , Guyton AC, Hall JE. Textbook of Medical Physiology. 11th ed, Elsevier;Fiorellini, J.P., Nevins, M.L., Norkin, A., Weber, H.P., Karimbux, N.Y., The effect of insulin therapy on osseointegration in a diabetic rat model (1999) Clin Oral Implants Res, 10 (5), pp. 362-368Lu, H., Kraut, D., Gerstenfeld, L.C., Graves, D.T., Diabetes interferes with the bone formation by affecting the expression of transcription factors that regulate osteoblast differentiation (2003) Endocrinology, 144 (1), pp. 346-352Nevins, M.L., Karimbux, N.Y., Weber, H.P., Giannobile, W.V., Fiorellini, J.P., Wound healing around endosseous implants in experimental diabetes (1998) Int J Oral Maxillofac Implants, 13 (5), pp. 620-629Claro, F.A., Lima, J.R., Salgado, M.A.C., Gomes, M.F., Porous Polyethylene for tissue engineering applications in diabetic rats treated with calcitonin: Histomorphometric analysis (2005) Int J Oral Maxillofac Implants, 20 (2), pp. 211-219Catanzaro-Guimarães, S.A., Catanzaro Guimarães, B.P., Garcia, R.B., Alle, N., Osteogenic potential of autogenic demineralized dentin implanted in bony defects in dogs (1986) Int J Oral Maxillofac Surg, 15 (2), pp. 160-169Bessho, K., Tagawa, T., Murata, M., Purification of rabbit bone morphogenetic protein derived from bone, dentin, and wound tissue after tooth extraction (1990) J Oral Maxillofac Surg, 48 (2), pp. 162-169Nakashima, M., Induction of dentine in amputated pulp of dogs by recombinant human bone morphogenetic proteins-2 and -4 with collagen matrix (1994) Arch Oral Biol, 39 (12), pp. 1085-1089Catanzaro-Guimarães SA. Possibility to reinforce bone repair with decalcified dentin matrix. In: Gesellschaft für orale Implantologie (ed.). Jahrbuch für Orale Implatologie. Berlin: Quintessenz1993. p. 33-
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