Chitosan/carrageenan nanoparticles: effect of cross-linking with tripolyphosphate

Chitosan/carrageenan/tripolyphosphate nanoparticles were prepared by polyelectrolyte complexation/ionic gelation, the latter compound acting as cross-linker. The incorporation of the three components in the nanoparticle matrix was assessed by analytical techniques (FTIR, XPS and TOF-SIMS). Using chitosan/carrageenan nanoparticles as control, the effect of the cross-linker in the particles properties was studied. A decrease in size (from 450-500 nm to 150-300 nm) and in zeta potential (from +75 - +85 mV to +50 - +60 mV), and an increase in production yield (from 15-20% to 25-35%), and in stability (from one week to up to 9 months) were observed. Also, a correlation between positive to negative charge ratios in the formulations and the above characteristics was established. The small size and high positive surface charge make the developed chitosan/carrageenan/tripolyphosphate nanoparticles potential tools for an application in mucosal delivery of macromolecules

N,N '-dimethyl-N,N '-dicyclohexylsuccinamide: A novel molecule for the separation and recovery of Pd(II) by liquid-liquid extraction

N,N'-dimethyl-N,N'-dicyclohexylsuccinamide (DMDCHSA) is investigated as a potential molecule for the liquid-liquid extraction of Pd(II) from chloride solutions for the first time. The effect of several parameters on Pd(II) extraction, such as the contact period between both phases, hydrochloric acid, extractant and hydrogen ion concentrations, is evaluated. Pd(II) extraction equilibrium is very fast (30 s) and the extraction percentage (%E) increases with the HCI concentration in the aqueous phases, being higher than 60% for [HCl] > 5 M. The loading capacity of DMDCHSA for Pd(II) is reasonable (molar ratio extractant/metal higher than 16). Several stripping agents (e.g. distilled water, 1 M HCl, seawater and 20 g/L chloride solution as NaCl) were successfully used to transfer Pd(II) to a new aqueous phase, and data obtained from five successive extraction-stripping cycles suggest a good DMDCHSA stability pattern. Attempts to replace 1,2-dichloroethane (1,2-DCE) by commercial and more environmentally friendly diluents showed much worse %E for Pd(II). Selectivity tests with binary, ternary and more complex metal ion solutions were carried out to evaluate the performance of DMDCHSA towards Pd(II) recovery from 6 M HCl, when in presence of Pt(IV), Fe(III), Zn(II), Al(III) and Ce(III), metal ions usually present in solutions that may result from the hydrometallurgical treatment of spent automobile catalytic converters. It was generally observed that the additional metal ions do not affect the recovery of Pd(II) by DMDCHSA, although Fe(III) and Pt(IV) were co-extracted in a great extent. A solvent extraction (SX) scheme is proposed, based on a previous separation of Fe(III) with tributylphosphate (TBP) and on the selective and sequential stripping of Pt(IV) and Pd(II) from the loaded DMDCHSA with 0.01 M thiourea in 0.5 M HCI and seawater, respectively. The dependence of the Pd(II) distribution ratios on DMDCHSA and acidity, complemented with UV-Visible spectroscopy data, points out to DMDCHSA:Pd(II) extracted species with a 2:1 molar ratio and suggests the occurrence of an outer-sphere ion pair reaction, in which both [PdCl4](2-) and HCI are extracted

Les pratiques d’attention à santé dans les établissements psychosociaux: les effets du mode de production capitaliste

O modo de produção de bens materiais é correlato ao modo de produção de saúde e indica as formas de subjetivação possíveis em uma sociedade, portanto, está relacionado às maneiras como impasses sociais e psíquicos se materializam. Os conflitos da luta de classes produzem contradições, de maneira que é crucial observar que os sintomas desencadeadores das crises vêm enunciar objeção ao contexto social no qual emergiram. Partindo da análise organizacional, constatamos que os estabelecimentos institucionais de saúde mental no contexto do modo capitalista de produção têm servido para agenciar essas crises no sentido de dissuadi-las. Observa-se que, apesar dos avanços da reforma psiquiátrica brasileira, os estabelecimentos psicossociais ainda servem à adaptação social, produzindo subjetividades alienadas e reproduzindo formas históricas de dominação-subordinação, como a internação psiquiátrica e a medicalização da vida e do sofrimento.El modo de producción de bienes materiales se correlaciona con el modo de producción de salud e indica las posibles formas de subjetivación en la sociedad, por tanto, se refiere a la manera en que los puntos muertos sociales y psíquicos se materializan. Los conflictos de la lucha de clases producen contradicciones, por lo que es fundamental señalar que los síntomas desencadenantes de las crisis vienen a declarar una objeción al contexto en que surgieron. Con base en el análisis organizacional, constatamos que los establecimientos institucionales de salud mental han servido para administrar esas crisis en el sentido de disuadirlas. Se observa que, pese a los avances de la reforma psiquiátrica brasileña, los establecimientos psicosociales todavía sirven a la adaptación social, producen subjetividad alienada y reproducen formas históricas de dominación-subordinación, como la internación psiquiátrica y la medicalización de la vida y del sufrimiento.The mode of production of material goods is correlated to the mode of production of health and indicates the possible forms of subjectivation in a society, thus, the mode of production is related to the ways in which the social and psychic impasses materialize. Conflicts of the class struggle produce contradictions, so it is crucial to note that the symptoms that trigger the crises come to enounce an objection to the social context in which they emerged. Based on institutional analysis, we find that mental health institutions in the context of the capitalist mode of production have served to manage these crises in order to dissuade them. It is observed that despite the advances of Brazilian psychiatric reform, psychosocial establishments still serve social adaptation, producing alienated subjectivities and reproducing historical forms of domination-subordination, such as psychiatric hospitalization and medicalization of life and suffering.Le mode de production des biens matériels est corrélatif au mode de production de santé et indique les façons de subjectivation possibles dans une société, donc, soit lié à la manière comme les impasses sociales et psychique se matérialisent. Les conflits de lutte de classes produisent contradictions, de manière qu’est cruciale regarder que les symptômes que déclenchent des crises viennent à énoncer une objectivation au contexte socioculturel dans lequel ils ont émergé. À partir de l’analyse institutionnelle, on a constaté que les practices de santé mentale au sein du mode capitaliste de production ont servi pour traiter ces crises afin de les dissuader. On observe que, malgré les progrès de la réforme psychiatrique brésilienne, l‘établissement psychosocial sert encore à l’adaptation sociale, en créant des subjectivités aliénées et en reproduisant formes historiques de domination-subordination, comme l’hospitalisation psychiatrique et la médicalisation de la vie e de la souffrance

Dual antibiotherapy of tuberculosis mediated by inhalable locust bean gum microparticles

Despite the existence of effective oral therapy, tuberculosis remains a deadly pathology, namely because of bacterial resistance and incompliance with treatments. Establishing alternative therapeutic approaches is urgently needed and inhalable therapy has a great potential in this regard. As pathogenic bacteria are hosted by alveolar macrophages, the co-localisation of antitubercular drugs and pathogens is thus potentiated by this strategy. This work proposes inhalable therapy of pulmonary tuberculosis mediated by a single locust bean gum (LBG) formulation of microparticles associating both isoniazid and rifabutin, complying with requisites of the World Health Organisation of combined therapy. Microparticles were produced by spray-drying, at LBG/INH/RFB mass ratio of 10/1/0.5. The aerodynamic characterisation of microparticles revealed emitted doses of more than 90% and fine particle fraction of 38%, thus indicating the adequacy of the system to reach the respiratory lung area, thus partially the alveolar region. Cytotoxicity results indicate moderate toxicity (cell viability around 60%), with a concentration-dependent effect. Additionally, rat alveolar macrophages evidenced preferential capture of LBG microparticles, possibly due to chemical composition comprising mannose and galactose units that are specifically recognised by macrophage surface receptors. (C) 2017 Elsevier B.V. All rights reserved.National Portuguese funding through FCT - Fundacao para a Ciencia e a Tecnologia [PTDC/DTP-FTO/0094/2012, UID/BIM/04773/2013, UID/Multi/04326/2013, UID/QUI/00100/2013, PEst-OE/QUI/UI4023/2011

Inhalable spray-dried chondroitin sulphate microparticles: effect of different solvents on particle properties and drug activity

Spray-drying stands as one of the most used techniques to produce inhalable microparticles, but several parameters from both the process and the used materials affect the properties of the resulting microparticles. In this work, we describe the production of drug-loaded chondroitin sulphate microparticles by spray-drying, testing the effect of using different solvents during the process. Full characterisation of the polymer and of the aerodynamic properties of the obtained microparticles are provided envisaging an application in inhalable tuberculosis therapy. The spray-dried microparticles successfully associated two first-line antitubercular drugs (isoniazid and rifabutin) with satisfactory production yield (up to 85%) and drug association efficiency (60%-95%). Ethanol and HCl were tested as co-solvents to aid the solubilisation of rifabutin and microparticles produced with the former generally revealed the best features, presenting a better ability to sustainably release rifabutin. Moreover, these presented aerodynamic properties compatible with deep lung deposition, with an aerodynamic diameter around 4 μm and fine particle fraction of approximately 44%. Finally, it was further demonstrated that the antitubercular activity of the drugs remained unchanged after encapsulation independently of the used solvent.UID/Multi/04326/2019; SFRH/BD/52426/2013; ED481B 2018/071info:eu-repo/semantics/publishedVersio

Inhalable antitubercular therapy mediated by locust bean gum microparticles

Tuberculosis remains a major global health problem and alternative therapeutic approaches are needed. Considering the high prevalence of lung tuberculosis (80% of cases), the pulmonary delivery of antitubercular drugs in a carrier system capable of reaching the alveoli, being recognised and phagocytosed by alveolar macrophages (mycobacterium hosts), would be a significant improvement to current oral drug regimens. Locust bean gum (LBG) is a polysaccharide composed of galactose and mannose residues, which may favour specific recognition by macrophages and potentiate phagocytosis. LBG microparticles produced by spray-drying are reported herein for the first time, incorporating either isoniazid or rifabutin, first-line antitubercular drugs (association efficiencies >82%). Microparticles have adequate theoretical properties for deep lung delivery (aerodynamic diameters between 1.15 and 1.67 μm). The cytotoxic evaluation in lung epithelial cells (A549 cells) and macrophages (THP-1 cells) revealed a toxic effect from rifabutin-loaded microparticles at the highest concentrations, but we may consider that these were very high comparing with in vivo conditions. LBG microparticles further evidenced strong ability to be captured by macrophages (percentage of phagocytosis >94%). Overall, the obtained data indicated the potential of the proposed system for tuberculosis therapy

Chitosan/sulfated locust bean gum nanoparticles: In vitro and in vivo evaluation towards an application in oral immunization

This work proposes the design of nanoparticles based on locus bean gum (LBG) and chitosan to be used as oral immunoadjuvant for vaccination purposes. LBG-based nanoparticles were prepared by mild polyelectrolyte complexation between chitosan (CS) and a synthesized LBG sulfate derivative (LBGS). Morphological characterization suggested that nanoparticles present a solid and compact structure with spherical-like shape. Sizes around 180-200 nm and a positive surface charge between +9 mV and +14 mV were obtained. CS/LBGS nanoparticles did not affect cell viability of Caco-2 cells after 3 h and 24h of exposure when tested at concentrations up to 1.0 mg/mL. Two model antigens (a particulate acellular extract HE of Salmonella enterica serovar Enteritidis, and ovalbumin as soluble antigen) were associated to CS/LBGS nanoparticles with efficiencies around 26% for ovalbumin and 32% for HE, which resulted in loading capacities up to 12%. The process did not affect the antigenicity of the associated antigens. BALB/c mice were orally immunized with ovalbumin-loaded nanoparticles (100 mu g), and results indicate an adjuvant effect of the CS/LBGS nanoparticles, eliciting a balanced Th1/Th2 immune response. Thus, CS/LBGS nanoparticles are promising as antigen mucosal delivery strategy, with particular interest for oral administration. (C) 2017 Elsevier B.V. All rights reserved.National Portuguese funding through FCT- Fundacao para a Ciencia e a Tecnologia, project [PTDC/SAU-FCF/100291/2008, PEst-OE/EQB/LA0023/2011]FEDER - Fundo Europeu de Desenvolvimento RegionalPortuguese funds through FCT - Fundacao para a Ciencia e a Tecnologia/Ministerio da Cienci

A importância do elogio nas emoções, motivação intrínseca e criatividade de crianças em idade escolar

O presente estudo procurou compreender os efeitos do elogio na criatividade. Foram analisadas variáveis como os estados afetivos (positivos e negativos), o orgulho (geral, autêntico ou arrogante), o fluxo emocional e a motivação intrínseca. Cinquenta alunos dos 7.º e 8.º anos de escolaridade de uma escola pública portuguesa realizaram o teste de criatividade TCT-DP e foram sujeitos, de forma aleatória, a uma de três condições experimentais: "elogio ao talento", "elogio ao empenho", "sem elogio". Também o tempo foi avaliado como uma medida comportamental de interesse pela tarefa e aparece associado positivamente ao pensamento não convencional e ao "score" total do teste de criatividade; a motivação intrínseca aparece associada positivamente ao "flow" e ao orgulho autêntico; a idade dos participantes aparece associada negativamente ao afeto positivo, orgulho autêntico e às dimensões de competência percebida e esforço/interesse da motivação intrínseca.The present study aimed to understand the effects of praise on creativity. Variables such as emotions (positive and negative), pride (general, authentic, and hubristic)flow, and intrinsic motivation were analized. Seventh- and eighth-grade students (n=50) in a Portuguese public school performed the TCT-DP creativity test and were randomly assigned to one of three experimental conditions: "praise for talent", "praise for effort", "no praise". The results indicated that there were no differences between groups. Also the time was evaluated as a behavioral measure of interest for the task is positively related with the unconventional thinking and the total score of the TCT-DP; intrinsic motivation is positively related with flow and authentic pride; the age of the participants is negatively related with positive affect, authentic pride, and the dimensions of the intrinsic motivation

As TIC em projetos de escola : estratégias de formação contínua de professores

Tese de doutoramento, Educação (Tecnologia da Informação e Comunicação na Educação), Universidade de Lisboa, Instituto de Educação, 2016Este estudo visa identificar projetos que integrem as tecnologias nas suas práticas e analisar o modo como professores e alunos utilizam as tecnologias. Pretende-se verificar até que ponto as tecnologias estão ou não integradas nas práticas e no currículo e que tipo de formação das Tecnologias da Informação e Comunicação (TIC) de professores se desenvolve no contexto dos projetos. Por fim, apresenta-se uma proposta de formação de professores no domínio das TIC. Este estudo surge com caráter exploratório, descritivo e interpretativo, sob a forma de estudo de casos múltiplos, já que aborda vários projetos, de três agrupamentos de escolas, em que as TIC são ferramentas centrais, utilizadas em projetos de investigação, intervenção ou de comunicação e onde a formação de professores surge de modo formal e informal. O estudo implica análise qualitativa e quantitativa descritiva de dados, recolhidos através de entrevistas de grupo, entrevistas semi estruturadas e relatos de práticas. A triangulação dos dados permite concluir que, no contexto dos projetos, a utilização das tecnologias varia conforme o tipo de projeto, sendo a tecnologia muito específica em alguns casos. O acesso aos recursos tecnológicos, o menor número de alunos nos projetos em relação às turmas e a inexistência de um currículo formal, permite uma abordagem informal, inovadora e exploratória. Os alunos apontam diversas falhas de conhecimento/competências, a nível das tecnologias aos professores, em particular no domínio técnico. A formação formal em TIC necessita ser reestruturada, visto que os professores reclamam uma formação mais ativa com aplicação prática aos seus próprios alunos.With this study we intend to identify projects involving the use of Information and Communication Technologies (ICT) in their practices and analyse the way teachers and pupils use the technologies. We intend to verify to what extend technologies are integrated in the practices and in the curriculum and what kind of teacher training is developed in the context of projects. At last, we present a suggestion of teacher training in the area of ICT. This study is exploratory descriptive and interpretative in the form of multiple case studies since it will address school projects, belonging to three different school groupings, in different areas where the ICT are central tools used in projects of investigation, communication and intervention, and where the teachers’ training appears in a formal and informal way. This study involves qualitative and quantitative descriptive data collected through interviews, focous group and practice reports. The triangulation of the obtained data lets us conclude that, in the context of projects, the use of technologies varies according to the type of project being the tool very specific in certain cases,the training of teachers and pupils happens mostly in an informal, innovative and exploratory way in the context of the project. The access to the technological resources, the small number of pupils in the projects, in comparison to classes, and the inexistence of a formal curricula allow an interaction between teachers and pupils that assume new roles of cooperation and learning together. Pupils point out several lacks of knowledge/competence at the level of technologies to the teachers, especially in the technical domain. The formal training in ICT must be restructured, as the teachers claim a more active training with a practical reach to their pupils

Inhalable chitosan microparticles for simultaneous delivery of isoniazid and rifabutin in lung tuberculosis treatment

The direct delivery of antibiotics to the lung has been considered an effective approach to treat pulmonary tuberculosis, which represents approximately 80% of total cases. In this sense, this work aimed at producing inhalable chitosan microparticles simultaneously associating isoniazid and rifabutin, for an application in pulmonary tuberculosis therapy. Spray-dried chitosan microparticles were obtained with adequate flow properties for deep lung delivery (aerodynamic diameter of 4 µm) and high drug association efficiencies (93% for isoniazid and 99% for rifabutin). The highest concentration of microparticles that was tested (1 mg/mL) decreased the viability of macrophage-differentiated THP-1 cells to around 60% after 24 h exposure, although no deleterious effect was observed in human alveolar epithelial (A549) cells. The release of LDH was, however, increased in both cells. Chitosan microparticles further evidenced capacity to activate macrophage-like cells, inducing cytokine secretion well above basal levels. Moreover, the propensity of macrophages to internalize microparticles was demonstrated, with uptake levels over 90%. Chitosan microparticles also inhibited bacterial growth by 96%, demonstrating that the microencapsulation preserved drug antibacterial activity in vitro. Overall, the obtained data suggest the potential of chitosan microparticles for inhalable lung tuberculosis therapy.PTDC/DTP-486 FTO/0094/2012info:eu-repo/semantics/publishedVersio