Universidade Positivo

About: Universidade Positivo is a education organization based out in Curitiba, Brazil. It is known for research contribution in the topics: Population & Medicine. The organization has 1290 authors who have published 1237 publications receiving 9335 citations. The organization is also known as: Positive University.

Efficacy of Utilizing Argon Plasma Coagulation for Weight Regain in Roux-en-Y Gastric Bypass Patients: a Multi-center Study

Abstract: Endoscopic approaches exist for targeting weight regain after Roux-en-Y gastric bypass (RYGB), including endoscopic suturing, clipping, and sclerotherapy. Argon plasma coagulation (APC) is a noncontact electrocoagulation method, and when used in RYGB patients, it has shown reduction in the diameter of the gastrojejunal anastomosis. To study the effectiveness of APC for weight regain in terms of weight loss for RYGB patients, from eight bariatric centers. A retrospective chart review was performed for 558 patients at eight bariatric centers in the USA (1) and Brazil (7) who underwent APC procedure between 31st July 2009 and 29th March 2017. APC was performed on patients who regained weight after RYGB procedure. Upon exploratory analysis of the individual BMI data, the mean BMI decreased slightly during the first 24 months and increased slightly afterwards following the APC intervention. The mean weight was 94.5 ± 18.6 kg and the mean BMI was 34.0 kg/m2 at APC. Where data were available, the mean of lowest weight was 67.0 ± 23.0 kg and the mean of lowest BMI was 24.1 kg/m2 following gastric bypass. The mean weight loss was 6.5, 7.7, and 8.3 kg at 6, 12, and 24 months, respectively, and the changes in weight over time was statistically significant (p < 0.0001). Multi-level for change model showed the low body mass index (BMI) group (BMI < 30 kg/m2) to have greater TWL than the high BMI (BMI ≥ 30 kg/m2) group at 6, 12, and 24 months. In the low BMI group, the mean TWL was 4.7, 6.1, 6.9, and 2.4%, at 6, 12, and 24 months, respectively. In the high BMI group, the mean TWL was 7.5, 10.4, 13.4, and 3.7%, at 6, 12, 24, and 36 months, respectively. Of the 333 patients in four centers who provided complication information, complications after APC included stenosis (n = 9), GJ ulcer (n = 3), vomiting (n = 3), GJ leakage (n = 2), and melena (n = 1). APC can be useful in reducing the regained weight after RYGB, and patients showed 6–10% total weight loss at 12 months. Randomized trials would be needed to validate the findings.

Influence of cellulose chemical pretreatment on energy consumption and viscosity of produced cellulose nanofibers (CNF) and mechanical properties of nanopaper

Abstract: Lignocellulosic fibers are the main sources for producing nanocellulose, in which mechanical methods are the most appropriate to achieve a high yield and generate low residue. High energy consumption is the major drawback in these processes, although they are the cheapest way to produce nanocellulose. Chemical pretreatment is one approach to further decrease the overall cost during defibrillation; however, the influence over sample viscosity and mechanical properties is yet to be investigated. Here, we study the influence of chemical pretreatments using NaOH and 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) on the mechanical, rheological and structural properties of cellulose nanofibers made from bleached eucalyptus pulp. Modification of samples was evidenced by their respective peaks on FTIR spectra. Sample crystallinity increased after partial hemicellulose and amorphous cellulose removal. In addition, a strong correlation between grinding efficiency and lower energy consumption was observed. However, a mild alkaline treatment may improve fiber strength at the expense of suspension stability and energy consumption. Modified nanofibers presented good potential for enhancing mechanical properties and/or improving suspension stability.

Phytodegradation Potential of Erythrina crista-galli L., Fabaceae, in Petroleum-Contaminated Soil

Abstract: This work aimed at investigating both the tolerance and the phytodegradation potential of Erythrina crista-galli L. in petroleum-contaminated soil. It consisted in analyzing E. crista-galli germination, surviving, growth, and development when cultivated at different contaminant concentrations and pollutant degradation rates. This specimen was selected because it presented a special behavior among others also exposed to petroleum in an accident that occurred in the Araucaria region (south of Brazil), resulting in a four-million-liter oil spill. The experiment was carried out in a greenhouse containing non-contaminated soil (NCS), vegetated contaminated soil (VCS), and non-vegetated contaminated soil (NVCS) at the following petroleum concentrations: 25 g kg−1 (VCS-25), 50 g kg−1 (VCS-50), and 75 g kg−1 (VCS-75). After 60 days, the soil samples were analyzed by gas chromatography. Germination was more and more evident as higher petroleum concentrations were observed. The surviving rates of groups NCS, VCS-25, VCS-50, and VCS-75 were 64%, 70%, 61%, and 96%, respectively. The VCS group growth was reduced when compared to the control group (NCS). The individuals exposed to petroleum pollution presented differences in the anatomic structure of their roots when compared to the NCS group. It was observed that the petroleum degradation rate was higher for VCS group than for NVCS. E. crista-galli is potentially recommended for petroleum-contaminated soils because of its positive association in the presence of contamination.