87 research outputs found
Associative Polymer-Polymer and Polymer-Surfactant Systems: Phase Behaviour and the Influence of Chemical Reactions
Aqueous mixtures of two non-ionic polymers, poly(acrylic acid) (PAA) and the amphiphilic triblock copolymer, (EO)27(PO)67(EO)27, known by its trade name Pluronic® P104, showed an associative phase separation (miscibility gap), which decreased with the decrease of PAA length. It was found that PAA is a much less selective “solvent” to P104 molecules than water. P104 aggregates are disintegrated and thus the liquid crystalline structures are destroyed upon replacement of water by PAA. Oppositely charged polyelectrolytes, DNA (double- or single-stranded) and two cationic derivatives of the hydroxyethyl cellulose (cat-HMHEC and cat-HEC) were mixed in water. An asymmetric associative phase separation was observed: small amounts of cat-(HM)HEC could precipitate DNA but large amounts of DNA were needed to precipitate the polycations. The rheological properties of the off-stoichiometric one-phase mixtures were investigated. The viscosity increased as the polymer content was increased and showed an interesting non-monotonic behaviour for the cat-HEC/dsDNA/H2O system. Redissolution of insoluble polyion-surfactant ion complex salts by adding excess surfactant was investigated using the simple approach of preparing the complex salts and mixing them with excess surfactant. The complex salts contained poly(acrylate) homopolymer or copolymers containing acrylate and NIPAM or DAM. The phase diagram for the long homopolyions systems presented a large miscibility gap, while efficient redissolution was obtained for shorter polyions. Incorporation of neutral units (more hydrophobic) originated efficient redissolution. Polymerizations in surfactant systems were performed. The acrylate counterion to the surfactant ion was polymerized under conditions where the growing poly(acrylate) chain was the sole counterion to the surfactant ion aggregates. Therefore the equilibrium phase diagrams constructed using the complex salts and excess surfactant predict the result of different pathways from polymerization reactions: phase diagrams come alive. The structure of the polyion-surfactant ion concentrated phase was changed in situ through the degradation of the surfactant into alcohol. The used cationic surfactant (decyl betainate) had a hydrolyzing ester group sensitive to high pH. The degradation of the surfactant into decanol changes the curvature of the ordered structure of the concentrated phase. Multi-lamellar nano-particles were obtained
El collage para el desarrollo de la grafomotricidad en los estudiantes de 4 años de la I.E. n° 408 Saños Chico El tambo - 2018
El presente trabajo de investigación se inició con el título siguiente: El collage para el desarrollo de la grafomotricidad en los estudiantes de 4 años de la I.E. Nº 408 Saños Chico, El Tambo – 2018, el problema general, ¿Cuál es la influencia del collage para el desarrollo de la grafomotricidad en los estudiantes de 4 años de la I.E. 408 Saños Chico – El Tambo – 2018?, el objetivo general fue Determinar la influencia del collage para el desarrollo de la grafomotricidad en los estudiantes de 4 años de la I.E. 408 Saños Chico – El Tambo – 2018 y la hipótesis, el Collage influye directamente en el desarrollo de la grafomotricidad en estudiantes de 4 años de la I.E. 408 Saños Chico- El Tambo. El método general que se utilizó en la presente tesis fue el método científico, a su vez el método específicos es el descriptivo, el estadístico y el experimental, el tipo de investigación fue aplicada, con un nivel explicativo, el diseño de investigación fue el experimental con carácter pre experimental porque solo se trabajó con un grupo o con una sola muestra, así también está muestra de estudio estuvo constituida por 16 estudiantes de 4 años, las técnicas fueron la observación, la encuesta, el fichaje, el instrumento aplicado fue una prueba pedagógica, el instrumento pasó por la validez y confiabilidad. Se llegó a la siguiente conclusión donde se determinó la influencia del collage en el desarrollo de la grafomotricidad en los estudiantes de cuatro años de la institución Educativa N° 408 del anexo de Saños chico del distrito de El Tambo, puesto que la prueba estadística chi cuadrada calculada fue mayor en comparación con el chi cuadrada teórica (23.28 > 7.378), también se obtuvo un nivel de significancia de 0.05, tal como se muestra en la contratación de hipótesis
Nivel de depresión en adolescentes de dos Instituciones Educativas de Cerro de Pasco - 2020
La investigación titulada Nivel de Depresión en Adolescentes de dos Instituciones Educativas de Cerro de Pasco – 2020 tuvo como objetivo determinar si existen diferencias significativas en el nivel de depresión en adolescentes de dos instituciones educativas de Cerro de Pasco, 2020. El método utilizado de forma general fue el método científico y de forma específica el método deductivo, conformado así un estudio de tipo básico y de diseño descriptivo comparativo. La muestra de estudio estuvo conformada por 145 estudiantes del 2do al 4to año de secundaria de dos Instituciones Educativas de Cerro de Pasco, el instrumento utilizado fue el Inventario de Depresión Infantil de Maria Kovacs. Los resultados evidenciaron que en ambas instituciones existe un nivel de sintomatología depresiva alto en el 63,4% de estudiantes, con respecto a las diferencias entre ambas Instituciones se determinó a través de un proceso estadístico que existen diferencias significativas en la sintomatología depresiva en ambas Instituciones Educativas
REMOVAL OF ORGANIC MATTER FROM WATER DISCARDED BY PAPER AND CELLULOSE MILLS AFTER UV/H2O2 TREATMENT
aper and cellulose mills effluents are composed by several combinations of chemical reagents used in productive stages and of substances originating from raw material, used to produce paper and cellulose pulp. Considering the volume of effluents generated by such industries and the current crisis of water resources, it is blatant the need of an efficient treatment for the discarded water. The advanced oxidative processes constitute an attractive option for treating several effluents. They are capable of promoting degradation and even mineralization of refractory pollutant particles. The current paper looks forward to assessing the performance of the UV/H2O2 process in removing organic matter present in the effluent of a paper mill. The research was carried out in a photochemical reactor with active capacity of 1300 mL. As source of UV radiation, it was used a medium pressure mercury lamp of 125 W. During 120 minutes of UV irradiation, six H2O2 concentrations were testes, varying between 15 and 200 mg.L-1. The results revealed the effectiveness of the process when removing 84% of the CDO and 91% of the BOD5. The performance of the UV/H2O2 process was influenced by the availability of H2O2 and the time of UV irradiation
Sustentabilidade e o comportamento do turista: uma discussão à luz da Psicologia Ambiental
The study on tourist behavior has aroused increasing interest in the areas of consumer behavior and sustainability, since this is seen as an agent that directly influences the sustainability of the destination. In light of environmental psychology, specifically the SOR of Mehrabian and Russell (1974) model, it is understood that the tourist can be influenced by stimuli in the environment. Apprehends that environmental stimuli, represented by features and other information concerning the dimensions of sustainability, arranged in a tourist destination, corresponding to the variables that can influence the behavior of tourists. In this sense, this essay proposes to discuss the relationship between the characteristics of sustainable tourism destinations and tourist behavior. It is believed that the tourist destination can stimulate behaviors towards sustainability, provided that it can properly utilize the characteristics of the environment to inform and educate tourists, especially those related to the dimensions of sustainability. The paper also proposes a framework in an attempt to better understand the relationship discussed and subsequent empirical studies suggest that share the same intent.O estudo sobre o comportamento do turista tem despertado crescente interesse nas áreas de comportamento do consumidor e sustentabilidade, uma vez que é visto como um agente que influencia diretamente a sustentabilidade do destino turístico. Sob a ótica da Psicologia Ambiental, mais especificamente do modelo S-O-R de Mehrabian e Russell (1974), entende-se que o turista pode ser influenciado por estímulos existentes no ambiente, já que estes, representados pelas características e demais informações concernentes às dimensões da sustentabilidade, dispostos na destinação turística, correspondem a variáveis que podem exercer influência sobre o comportamento do turista. Nesse sentido, o presente ensaio propôs-se a discutir a relação entre as características de sustentabilidade de destinos turísticos e o comportamento do turista. Acredita-se que o destino turístico é capaz de estimular comportamentos voltados para a sustentabilidade, desde que consiga utilizar adequadamente as características do ambiente para informar e instruir o turista, sobretudo aquelas relacionadas às dimensões da sustentabilidade. Este trabalho também propõe um framework na tentativa de melhor compreender a relação aqui discutida e sugerir estudos empíricos posteriores que compartilhem do mesmo intento
TRATAMENTO DE EFLUENTE DE UMA INDÚSTRIA DE PAPEL E CELULOSE POR OZONIZAÇÃO
O processo de extração de celulose e de produção de papel gera efluentes com alto potencial poluidor, com elevado valor de Demanda Química de Oxigênio (DQO), Demanda Bioquímica de Oxigênio (DBO), cor e teor de lignina. Assim, a busca por processos alternativos faz-se necessária para reduzir os impactos desse efluente nos corpos receptores. Com o presente trabalho, teve-se por objetivo caracterizar o efluente proveniente de uma indústria de papel e celulose de Fraiburgo, no Meio-Oeste de Santa Catarina, e avaliar o efeito da ozonização como alternativa de tratamento. O efluente foi caracterizado quanto à DQO, DBO, turbidez, cor, sólidos sedimentáveis, nitrogênio, fósforo, temperatura, pH e lignina residual. Após a caracterização, a amostra do efluente foi submetida à ozonização (200mg/hora) por períodos de 15, 30 e 60 minutos. Os resultados das análises demonstram grande variação nos parâmetros avaliados, verificou-se que a DQO variou de 1.906,6mg/L a 5.983,3mg/L, a DBO variou de 177,96 a 625,33, a turbidez variou entre 2.90 NTU e 5.21 NTU, a cor apresentou variação entre 115 units/PtCo e 453 units/PtCo, a temperatura variou de 36 ºC a 48 ºC, e o pH, de 6,95 a 8,25. Nos ensaios de ozonização foi observada uma redução significativa dos parâmetros DQO, DQO/DBO, cor e turbidez. A redução da cor variou de 8,87% a 85,53%, a redução da DQO variou de 19,34% a 81,82% e a redução da turbidez, de 4,35% a 72,6%, conforme tempo de exposição e efluente. A relação DQO/DBO apresentou significativa redução após ozonização, a relação inicial foi de 11,39, 5,67 e 9,76, sendo a final de 2,09, 3,31 e 4,04 após 60 minutos de ozonização. Verificou-se que o melhor desempenho foi obtido em pH alcalino e após 15 minutos de ozonização. Nenhuma redução significativa foi observada para o parâmetro lignina. Palavras-chave: Efluente. Ozonização. Processos físico-químicos
Wet market biosecurity reform : three social narratives influence stakeholder responses in Vietnam, Kenya, and the Philippines
Funding: This research was funded by the Australian Agricultural Centre for International Agricultural Research (ACIAR), grant number LS/2020/204. The funders played no role in the design or implementation of the research. Grant recipients included: KB, RG, SB, TH, CM. All authors received salary support from the grant.In 2020, Covid-19 led to global policy statements promoting bans and reforms to wet markets in Asia and Africa to prevent future pandemics. We conducted a comparative, exploratory qualitative study in 2021 in three countries (Kenya, Vietnam and the Philippines) to understand the social and political dimensions to biosecurity reform at wet markets. This included 60 key informant interviews and rapid ethnographic research in 15 markets, as well as a review of policy documents and online media articles. We found no evidence that the rhetoric of pandemic spillover that emerged in 2020 had any influence on policy or reform efforts apart from those related to Covid-19 infection control. Rather, we identified three main narratives that frame the problem of biosecurity and preferences for reform. The first, a human health narrative, questioned global framings about pandemic risk, viewed markets as sources for food security rather than disease, emphasized the need to strengthen the control of endemic diseases, and conceptualized health through the lens of ‘freshness’ rather than biomedical categories. A second modernization narrative approached biosecurity as part of a broader process of socio-economic development that emphasized infrastructural gaps, spatial arrangements, cleanliness and a conflict between reform and economic interests. A third narrative centered on local livelihoods and the tension between local market stakeholders and biosecurity and modernization efforts. This final narrative called into question the appropriateness of certain regulations and policies, including bans and closures, emphasized the importance of preserving cultural heritage and highlighted the need for collective political action to resist certain veterinary policies. In conclusion, wet market biosecurity strategies occur in the context of three contrasting narratives that emphasize different aspects of health and risk, and reflect different worldviews and interests. Within this context, there is a need for local government to strengthen market management and biosecurity in ways that enhance the agency of market stakeholders and strengthen local livelihoods and food security as part of a pluralistic and democratic politics.Publisher PDFPeer reviewe
Effect of obesity on biodistribution of nanoparticles
[EN] Nanoparticles have specific features (lipophilicity, surface charge, composition and size). Studies regarding the biological behavior of nanoparticles in diseases such diabetics and obesity are scarce. Here, we evaluated two nanoparticles: magnetic core mesoporous silica (MSN) (58 nm) and polycaprolactone (PCL) nanoparticle (280 nm) in obese mice. Changes in the biodistribution were observed, especially considering the mononuclear phagocyte system (MPS), and the visceral fat tissue. Nonetheless, our data corroborates the influence of size in the biodistribution in obese animals, supporting that smaller nanoparticles, may show a higher tissue deposition at spleen, due the associated splenomegaly and the complications arising from this state. Finally, our study demonstrated that, in obesity, probably due the low-grade inflammatory state associated with metabolic syndrome a difference in accumulation of nanoparticles was found, with profound impact in the tissue deposition of nanoparticles.The authors would like to thank the National Scientific and Technological Research Council (CNPQ) - no. 400018/2016-0 and the Rio de Janeiro State Research Foundation (FAPERJ) - E-26/102.940/2012 for funding. Authors also gratefully acknowledge the financial support from the Ministerio de Economía y Competitividad (Project MAT2012-38429-C04-01) and the Generalitat Valenciana (project PROMETEO/2009/016) for support.Felismino, CDJ.; Helal-Neto, E.; Portilho, F.; Rocha Pinto, S.; Sancenón Galarza, F.; Martínez-Máñez, R.; Ferreira, ADA.... (2018). Effect of obesity on biodistribution of nanoparticles. Journal of Controlled Release. 281:11-18. https://doi.org/10.1016/j.jconrel.2018.05.003S111828
Association of Candidate Gene Polymorphisms With Chronic Kidney Disease: Results of a Case-Control Analysis in the Nefrona Cohort
Chronic kidney disease (CKD) is a major risk factor for end-stage renal disease, cardiovascular disease and premature death. Despite classical clinical risk factors for CKD and some genetic risk factors have been identified, the residual risk observed in prediction models is still high. Therefore, new risk factors need to be identified in order to better predict the risk of CKD in the population. Here, we analyzed the genetic association of 79 SNPs of proteins associated with mineral metabolism disturbances with CKD in a cohort that includes 2, 445 CKD cases and 559 controls. Genotyping was performed with matrix assisted laser desorption ionizationtime of flight mass spectrometry. We used logistic regression models considering different genetic inheritance models to assess the association of the SNPs with the prevalence of CKD, adjusting for known risk factors. Eight SNPs (rs1126616, rs35068180, rs2238135, rs1800247, rs385564, rs4236, rs2248359, and rs1564858) were associated with CKD even after adjusting by sex, age and race. A model containing five of these SNPs (rs1126616, rs35068180, rs1800247, rs4236, and rs2248359), diabetes and hypertension showed better performance than models considering only clinical risk factors, significantly increasing the area under the curve of the model without polymorphisms. Furthermore, one of the SNPs (the rs2248359) showed an interaction with hypertension, being the risk genotype affecting only hypertensive patients. We conclude that 5 SNPs related to proteins implicated in mineral metabolism disturbances (Osteopontin, osteocalcin, matrix gla protein, matrix metalloprotease 3 and 24 hydroxylase) are associated to an increased risk of suffering CKD
- …