Rationale, study design, and analysis plan of the Alveolar Recruitment for ARDS Trial (ART): Study protocol for a randomized controlled trial

Background: Acute respiratory distress syndrome (ARDS) is associated with high in-hospital mortality. Alveolar recruitment followed by ventilation at optimal titrated PEEP may reduce ventilator-induced lung injury and improve oxygenation in patients with ARDS, but the effects on mortality and other clinical outcomes remain unknown. This article reports the rationale, study design, and analysis plan of the Alveolar Recruitment for ARDS Trial (ART). Methods/Design: ART is a pragmatic, multicenter, randomized (concealed), controlled trial, which aims to determine if maximum stepwise alveolar recruitment associated with PEEP titration is able to increase 28-day survival in patients with ARDS compared to conventional treatment (ARDSNet strategy). We will enroll adult patients with ARDS of less than 72 h duration. The intervention group will receive an alveolar recruitment maneuver, with stepwise increases of PEEP achieving 45 cmH(2)O and peak pressure of 60 cmH2O, followed by ventilation with optimal PEEP titrated according to the static compliance of the respiratory system. In the control group, mechanical ventilation will follow a conventional protocol (ARDSNet). In both groups, we will use controlled volume mode with low tidal volumes (4 to 6 mL/kg of predicted body weight) and targeting plateau pressure <= 30 cmH2O. The primary outcome is 28-day survival, and the secondary outcomes are: length of ICU stay; length of hospital stay; pneumothorax requiring chest tube during first 7 days; barotrauma during first 7 days; mechanical ventilation-free days from days 1 to 28; ICU, in-hospital, and 6-month survival. ART is an event-guided trial planned to last until 520 events (deaths within 28 days) are observed. These events allow detection of a hazard ratio of 0.75, with 90% power and two-tailed type I error of 5%. All analysis will follow the intention-to-treat principle. Discussion: If the ART strategy with maximum recruitment and PEEP titration improves 28-day survival, this will represent a notable advance to the care of ARDS patients. Conversely, if the ART strategy is similar or inferior to the current evidence-based strategy (ARDSNet), this should also change current practice as many institutions routinely employ recruitment maneuvers and set PEEP levels according to some titration method.Hospital do Coracao (HCor) as part of the Program 'Hospitais de Excelencia a Servico do SUS (PROADI-SUS)'Brazilian Ministry of Healt

Photocatalytic activity in composites of hydrotalcites-TiO 2 impregnated with metallic nanoparticles and TiO 2 -MgZnAl mixed oxides

A utilização do TiO 2 como fotocatalisador apresenta algumas desvantagens como os processos de recombinação elétrons-lacuna, os quais diminuem a sua atividade fotocatalítica; somente ser fotoativado pela radiação na região do UV; e tendência a agregação das suas nanopartículas. Desta forma, este trabalho consistiu-se no preparo de compósitos contendo TiO 2 de forma a obter uma melhoria em suas propriedades funcionais. A atividade fotocatalítica foi significativamente afetada pela quantidade de TiO 2 suportada no hidróxido duplo lamelar de MgAl (hidrotalcita). Várias amostras de fotocatalisadores foram preparadas com diferentes nanopartículas metálicas (Ag, Cu ou Ni). O compósito fotocatalisador mais eficiente foi obtido na forma calcinada, com a relação molar de 2:1:1 (Mg:Al:Ti) e o metal Ag (2%, m/m) sendo denominado por HTC/TiO 2 -Ag(2). Este compósito apresentou aproximadamente 100% de degradação e 85% de mineralização do fenol, em 300 min. Compósitos contendo TiO 2 associado ao óxido de zinco obtido pela calcinação do hidróxido duplo lamelar ternário de MgZnAl também foram preparados com sucesso. Os fotocatalisadores foram avaliados em diferentes razões molares de Zn 2+ /Mg 2+ sendo que o melhor fotocatalisador foi obtido para a razão molar Zn 2+ /Mg 2+ igual a 5% e foi denominado por TiO 2 /MgZnAl-5. Este fotocatalisador removeu aproximadamente 100% de fenol e 80% de COT, em 360 minutos. Os novos compósitos fotocatalisadores preparados neste trabalho apresentaram um sinergismo de efeito ocasionado pelo suporte de hidróxido duplo lamelar, presença das nanopartículas metálicas (Ag, Cu ou Ni) ou óxido de zinco os quais, associados à fotoatividade do TiO 2, resultaram na formação de um compósito com alta capacidade fotocatalítica. Os compósitos apresentaram boa estabilidade após 5 ciclos de reuso, capacidade de recuperação e menor agregação de suas nanopartículas, mostrando assim um potencial promissor para aplicações práticas.Use of TiO 2 as photocatalyst has some disadvantages such as electron-hole recombination processes which reduces its photocatalytic activity; only be photoactivated by radiation in UV region; and the tendency of aggregation when used as nanopowder. This study consisted in preparing composites containing TiO 2 to obtain an improvement in their functional properties. Photocatalytic activity was affected significantly by the amount of TiO 2 supported on lamellar double hydroxide of MgAl (hydrotalcite). A series of photocatalysts were prepared with different metallic nanoparticles (Ag, Cu or Ni). The most efficient photocatalyst composite was obtained calcined form, molar ratio 2:1:1 (Mg:Al:Ti) and Ag metal (2 wt.%) denominated as HTC/TiO 2 -Ag(2). This composite showed highest efficiency degradation by removing about 100% phenol by analysis via HPLC-DAD and 85% TOC after 300 minutes. Composites containing TiO 2 combined with zinc oxide obtained by the calcination of ternary (MgZnAl) layered double hydroxides were also successfully prepared in this work. The photocatalysts were evaluated at different Zn 2+ /Mg 2+ molar rations and the most efficient photocatalyst was obtained at a Zn 2+ /Mg 2+ equal to 5% (TiO 2 /MgZnAl- 5). This photocatalyst removed approximately 100% phenol and 80% COT after 360 minutes. The new composite photocatalyst prepared in this study showed a synergy effect of the layered double hydroxide support, presence of metal nanoparticles (Ag, Cu or Ni) or zinc oxide associated with photoactivity of TiO 2 , resulting in formation of a composite with high photocatalytic capacity. The composites showed good stability after 5 cycles, reduced agglomeration and ease separation by sedimentation at the end of the processes, thus showing a promising potential for practical applications.Coordenação de Aperfeiçoamento de Pessoal de Nível Superio

Evaluation of the adsorption-photodegradation with chitosan-TiO2 beads for the treatment of effluents of textile industry

De maneira geral, as indústrias têxteis apresentam um elevado potencial poluente. As principais razões para essa poluição são a geração de elevados volumes de resíduos líquidos contendo alta carga orgânica e forte coloração derivada dos corantes. Entretanto, estes efluentes têxteis são possíveis de serem tratados por rotinas convencionais que envolvem processos físicos, químicos e biológicos onde os substratos são removidos por simples adsorção. O caráter não destrutivo desta sequência de procedimentos representa um sério problema no setor, incentivando a criação de processos destrutivos de maior eficiência. O objetivo deste trabalho é aplicar no tratamento de efluentes de indústrias têxteis o TiO2, amplamente utilizado como fotocatalizador na degradação de compostos orgânicos em águas e efluentes, associado com a quitosana, um biopolímero amplamente utilizado em tratamentos de águas devido ao seu alto poder de adsorção. Desta forma, foram preparadas esferas de quitosana-TiO2-reticulada (QTS-TiO2-R) visando a sua aplicação na descoloração de corantes têxteis em meio aquoso e na descoloração dos corantes em efluentes têxteis tratados fortificados. Os corantes selecionados para estudos foram o direct red 80 (DR80) e reactive blue 21 (RB21). Em meio aquoso, as esferas apresentaram alta capacidade de descoloração das soluções dos corantes direct red 80 e reactive blue 21 chegando a cerca de 100%, num tempo de 26 horas em pH 7. As esferas apresentaram uma baixa capacidade de adsorção, sendo o efeito principal na remoção dos corantes a fotodegradação. A descoloração do corante DR80 em solução de efluente de indústria têxtil tratado apresentou uma porcentagem de remoção de cerca de 50%, enquanto para o RB21 esta descoloração ficou em cerca de 90%, no tempo de 91 horas em pH 7. Foi avaliada a reutilização das esferas por 5 vezes consecutivas, onde se observou após o quinto ciclo uma diminuição de sua eficiência foto-oxidativa de cerca de 7,1% para o DR80 e de 15,1% para o RB21 em efluente de indústrias têxteis tratado fortificados com 50 mg L-1 destes corantes. As esferas apresentaram eficiente capacidade de descoloração das soluções dos corantes DR80 e RB21 até o 5 ciclo de reutilização. Desta forma, as esferas de QTS-TiO2-R podem ser incluídas como novos adsorventes-fotooxidativos, mostrando excelente desempenho na fotodegradação de corantes, podendo ser utilizadas como uma nova tecnologia de remoção aplicada ao polimento de efluentes industriais. Além das características favoráveis, são interessantes do ponto de vista econômico, já que utilizam material natural, não tóxico, reagentes de baixo custo, de fácil disponibilidade e preparação.Overall, textile industries have high pollution potential. The main reasons for this pollution are the production of high volumes of liquid waste containing high organic load and the strong coloring derived from the colorants. However, these textile effluents are likely to be treated by conventional routines that involve physical, chemical and biological processes in which substrates are removed by simple adsorption. The nondestructive nature of this sequence of procedures represents a serious problem in the sector, encouraging the creation of destructive processes of greater efficiency. The aim of this study is to apply in the treatment of effluents from textile industries the TiO2, widely used as a photocatalyst in the degradation of organic compounds in water and wastewater, associated with chitosan, a biopolymer widely used in water treatment due to its high adsorption power. Thus, beads of chitosan-TiO2-reticulate (CTS-TiO2-R) were prepared aiming at its application in the discoloration of textile colorants in aqueous medium and the discoloration of pigments in treated fortified textile effluents. The colorants selected for study were the direct red 80 (DR80) and the reactive blue 21 (RB21). In water, the spheres presented high capacity of discoloration of these colorants solutions, reaching nearly 100% in a period of 26 hours at pH 7. The beads had low adsorption capacity, being the photodegradation the main effect in the removal of colorants. The discoloration of the colorant DR80 in a solution of textile industry treated effluent showed a removal percentage of about 50%, while for the RB21 this discoloration was around 90% in a period of 91 hours at pH 7. We evaluated the reuse of the beads for 5 consecutive times, when it was observed that after the fifth cycle there was a decrease of its photo-oxidative efficiency of about 7.1% for the DR80 and 15.1% for the RB21 in textile industry treated effluent, fortified with 50 mg L-1 of these colorants. The beads showed efficient discoloration capacity of the colorants DR80 and RB21 solutions until the 5th cycle of reuse. Therefore, the beads of CTS-TiO2-R can be included as new photo-oxidative-adsorbents, showing excellent performance on the photodegradation of colorants, making its use possible as a new removal technology applied to the buffing of industrial effluents. In addition to the favorable characteristics, this is interesting from an economic perspective, since they use non toxic and natural material, and also low cost reactants, which are easy to be found and prepared.Conselho Nacional de Desenvolvimento Científico e Tecnológic

Enhanced photocatalytic activity of TiO2-impregnated with MgZnAl mixed oxides obtained from layered double hydroxides for phenol degradation

A series of TiO2/MgZnAl photocatalysts were successfully synthesized from ternary (Mg, Zn and Al) layered double hydroxides impregnated with TiO2 nanoparticles by the co-precipitation method at variable pH with different Zn2+/Mg2+ molar ratios. The composite photocatalysts were calcined at 500 °C resulting in the incorporation of oxide zinc, in the calcined MgZnAl LDH structure. Synergistic effect between ZnO and TiO2 lead to significant enhancement of TiO2/MgZnAl photocatalytic activity. Composite photocatalysts were characterized by ICP-MS, N2 adsorption-desorption, XRD, SEM, EDS, IR and UV–vis DRS. Phenol in aqueous solution (50 mg/L) was used as a model compound for evaluation of UV–vis (filter cut-off for λ > 300 nm) photocatalytic activity. The most efficient photocatalyst composite was obtained at a 5% Zn2+/Mg2+ molar ratio, in the catalyst identified as TiO2/MgZnAl-5. This composite catalyst had high photocatalytic activity, completely destroying phenol and removing 80% of total organic carbon in solution after 360 min. The TiO2/MgZnAl-5 catalyst remained relatively stable, presenting a 15% decrease in phenol degradation efficiency after five consecutive photocatalytic cycles

Rationale, study design, and analysis plan of the Alveolar Recruitment for ARDS Trial (ART): Study protocol for a randomized controlled trial

Background: Acute respiratory distress syndrome (ARDS) is associated with high in-hospital mortality. Alveolar recruitment followed by ventilation at optimal titrated PEEP may reduce ventilator-induced lung injury and improve oxygenation in patients with ARDS, but the effects on mortality and other clinical outcomes remain unknown. This article reports the rationale, study design, and analysis plan of the Alveolar Recruitment for ARDS Trial (ART). Methods/Design: ART is a pragmatic, multicenter, randomized (concealed), controlled trial, which aims to determine if maximum stepwise alveolar recruitment associated with PEEP titration is able to increase 28-day survival in patients with ARDS compared to conventional treatment (ARDSNet strategy). We will enroll adult patients with ARDS of less than 72 h duration. The intervention group will receive an alveolar recruitment maneuver, with stepwise increases of PEEP achieving 45 cmH(2)O and peak pressure of 60 cmH2O, followed by ventilation with optimal PEEP titrated according to the static compliance of the respiratory system. In the control group, mechanical ventilation will follow a conventional protocol (ARDSNet). In both groups, we will use controlled volume mode with low tidal volumes (4 to 6 mL/kg of predicted body weight) and targeting plateau pressure <= 30 cmH2O. The primary outcome is 28-day survival, and the secondary outcomes are: length of ICU stay; length of hospital stay; pneumothorax requiring chest tube during first 7 days; barotrauma during first 7 days; mechanical ventilation-free days from days 1 to 28; ICU, in-hospital, and 6-month survival. ART is an event-guided trial planned to last until 520 events (deaths within 28 days) are observed. These events allow detection of a hazard ratio of 0.75, with 90% power and two-tailed type I error of 5%. All analysis will follow the intention-to-treat principle. Discussion: If the ART strategy with maximum recruitment and PEEP titration improves 28-day survival, this will represent a notable advance to the care of ARDS patients. Conversely, if the ART strategy is similar or inferior to the current evidence-based strategy (ARDSNet), this should also change current practice as many institutions routinely employ recruitment maneuvers and set PEEP levels according to some titration method.13Hospital do Coracao (HCor) as part of the Program 'Hospitais de Excelencia a Servico do SUS (PROADI-SUS)'Brazilian Ministry of Healt