Avaliação de processo alcalino para obtenção de quitosana fúngica

Chitosan is a biopolymer with numerous applications in food, medical, pharmaceutical and environmental fields, and it can be obtained from chitin deacetylation present in fungal biomass. This study evaluated the fungal biomass deacetylation process with variations in sodium hydroxide solution concentrations, biomass proportions, process time and equipment. The fungal biomass was produced by Aspergillus niger fungus DAOM in potato dextrose broth medium via submerged bioprocesses. Deacetylation of the biomass was conducted using 4% (1:40 m v-1) NaOH solution in autoclave and 45% (1:20 m v-1) in stirred reactor. The degree of deacetylation for both techniques was similar (>60%). However, the autoclave process presented higher yield (14.29%). In addition, the functional groups presented similarities between the biopolymer samples, evidencing groups of hydroxyls, primary and secondary amines. Therefore, the process using 4% NaOH in autoclave contributed to minimize the negative environmental impacts of chitosan production.A quitosana é um biopolímero com inúmeras aplicações nas áreas de alimentos, médica, farmacêutica e ambiental, e pode ser obtida a partir da desacetilação da quitina presente na biomassa fúngica. Este estudo avaliou o processo de desacetilação de biomassa fúngica com variações nas concentrações da solução de hidróxido de sódio, proporções de biomassa, tempo de processo e tipo de equipamento. A biomassa fúngica foi produzida pelo fungo Aspergillus niger DAOM em meio potato dextrose broth via bioprocessos submersos. A desacetilação da biomassa foi conduzida utilizando solução de NaOH em concentrações de 4% (1:40 m v-1) em autoclave e 45% (1:20 m v-1) em reator agitado. O grau de desacetilação para as duas técnicas foram similares (>60%). Entretanto, o processo em autoclave apresentou maior rendimento (14,29%). Além disso, os grupos funcionais apresentaram semelhanças entre as amostras do biopolímero, se evidenciando grupos de hidroxilas, aminas primárias e secundárias. Portanto, o processo com o uso de NaOH 4% em autoclave contribuiu na minimização dos aspectos ambientais negativos da produção da quitosana

Hierarchical Submission in a Grid Environment

One of the challenges in grid computing research is to provide means to automatically submit, manage, and monitor applications which spread a large number of tasks. The usual way of managing these tasks is to represent each one as an explicit node in a graph, and this is the approach taken by many grid systems up to date. This approach can quickly saturate the machine where the application is launched, as we increase the number of tasks. In this work we present and validate a novel architectural model, GRAND (Grid Robust ApplicatioN Deployment), whose main objective is to deal with the problem of memory and load saturation of the submission machine. GRAND is implemented at a middleware level, aiming at providing a distributed task submission through a hierarchical organization. This paper provides an overview of the GRAND submission model as well our implementation. Initial results show that our approach can be much more effective than other approaches in the literature

Evaluation of a quality improvement intervention to reduce anastomotic leak following right colectomy (EAGLE): pragmatic, batched stepped-wedge, cluster-randomized trial in 64 countries

Background Anastomotic leak affects 8 per cent of patients after right colectomy with a 10-fold increased risk of postoperative death. The EAGLE study aimed to develop and test whether an international, standardized quality improvement intervention could reduce anastomotic leaks. Methods The internationally intended protocol, iteratively co-developed by a multistage Delphi process, comprised an online educational module introducing risk stratification, an intraoperative checklist, and harmonized surgical techniques. Clusters (hospital teams) were randomized to one of three arms with varied sequences of intervention/data collection by a derived stepped-wedge batch design (at least 18 hospital teams per batch). Patients were blinded to the study allocation. Low- and middle-income country enrolment was encouraged. The primary outcome (assessed by intention to treat) was anastomotic leak rate, and subgroup analyses by module completion (at least 80 per cent of surgeons, high engagement; less than 50 per cent, low engagement) were preplanned. Results A total 355 hospital teams registered, with 332 from 64 countries (39.2 per cent low and middle income) included in the final analysis. The online modules were completed by half of the surgeons (2143 of 4411). The primary analysis included 3039 of the 3268 patients recruited (206 patients had no anastomosis and 23 were lost to follow-up), with anastomotic leaks arising before and after the intervention in 10.1 and 9.6 per cent respectively (adjusted OR 0.87, 95 per cent c.i. 0.59 to 1.30; P = 0.498). The proportion of surgeons completing the educational modules was an influence: the leak rate decreased from 12.2 per cent (61 of 500) before intervention to 5.1 per cent (24 of 473) after intervention in high-engagement centres (adjusted OR 0.36, 0.20 to 0.64; P < 0.001), but this was not observed in low-engagement hospitals (8.3 per cent (59 of 714) and 13.8 per cent (61 of 443) respectively; adjusted OR 2.09, 1.31 to 3.31). Conclusion Completion of globally available digital training by engaged teams can alter anastomotic leak rates. Registration number: NCT04270721 (http://www.clinicaltrials.gov)