Síntese de ferrita NiFe2O4 e sua incorporação em compósitos de poliamida 6: Parte 1: caracterização estrutural por drx e mev dos pós e dos compósitos Synthesis of NiFe2O4 ferrite and its incorporation in nylon 6: Part 1: structural characterization by xrd and sem of ferrite powders and its composites

As ferritas geralmente são absorvedoras de radiação eletromagnética e apresentam a versatilidade de poderem ser manufaturadas com geometrias diferentes, e usadas na forma de ferritas policristalinas (corpo sinterizado) ou de compósitos de ferrita (adição de pó em matriz apropriada). A poliamida 6, por sua vez, pertence a uma classe de polímeros atraentes para aplicações em engenharia devido à combinação de propriedades como: estabilidade dimensional, boa resistência ao impacto sem entalhe e excelente resistência química. O objetivo deste trabalho foi sintetizar pós de ferrita NiFe2O4, e avaliar a adição destes em concentrações de 10, 30, 50 e 60% em massa a uma matriz polimérica de poliamida 6 usando um misturador da Haake Blücher, para obter compósitos de poliamida 6/NiFe2O4. Os pós e os compósitos foram caracterizados por difração de raios X (DRX) e microscopia eletrônica de varredura (MEV). Os difratogramas de raios X mostraram picos característicos da poliamida 6 e da ferrita. Por MEV foi observada a formação de aglomerados grandes para a concentração de 60% e, uma grande quantidade de poros. Para a concentração de 10%, as partículas ficaram mais dispersas, com menos aglomerados e menos poros no compósito.Ferrites normally absorb electromagnetic radiation, being versatile in that they can be manufactured in different geometries and used as polycrystalline ferrites (sintered body) or composites of ferrite (with addition of the powder to an appropriate matrix). On the other hand, nylon 6 is an attractive polymer for engineering applications due to the combination of properties such as dimensional stability, good impact strength without notch indentation and excellent chemical resistance. The aim of this paper was to synthesize ferrite (NiFe2O4) powders and to evaluate their addition in concentrations of 10, 30, 50 and 60 wt% into a nylon 6 polymer matrix using a Haake Blücher mixer. The powders and the composites were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The X-ray diffractograms showed characteristic peaks of nylon 6 and ferrite. With SEM, large clusters were observed for the concentration of 60%, with a large amount of pores. For the 10% concentration, the particles became more dispersed with less clusters and less pores in the composite

Leptospirosis in a subsistence farming community in Brazil.

Submitted by Ana Maria Fiscina Sampaio ([email protected]) on 2014-04-24T12:11:29Z No. of bitstreams: 1 Lacerda H Leptospirosis in a subsistence farming....pdf: 148492 bytes, checksum: 858db18a733d1ebcc1bdf5758500f22d (MD5)Made available in DSpace on 2014-04-24T12:11:29Z (GMT). No. of bitstreams: 1 Lacerda H Leptospirosis in a subsistence farming....pdf: 148492 bytes, checksum: 858db18a733d1ebcc1bdf5758500f22d (MD5) Previous issue date: 2008Gonçalo Moniz Research Center. Department of Biochemistry. Universidade Federal do Rio Grande do Norte. Natal, RN, BrasilGonçalo Moniz Research Center. Department of Biochemistry. Universidade Federal do Rio Grande do Norte. Natal, RN, BrasilGonçalo Moniz Research Center. Department of Biochemistry. Universidade Federal do Rio Grande do Norte. Natal, RN, BrasilGonçalo Moniz Research Center. Department of Biochemistry. Universidade Federal do Rio Grande do Norte. Natal, RN, BrasilGonçalo Moniz Research Center. Department of Biochemistry. Universidade Federal do Rio Grande do Norte. Natal, RN, BrasilGonçalo Moniz Research Center. Department of Biochemistry. Universidade Federal do Rio Grande do Norte. Natal, RN, BrasilGonçalo Moniz Research Center. Department of Biochemistry. Universidade Federal do Rio Grande do Norte. Natal, RN, BrasilFundação Oswaldo Cruz. Centro de Pesquisa Gonçalo Moniz. Salvador, BA, BrasilFundação Oswaldo Cruz. Centro de Pesquisa Gonçalo Moniz. Salvador, BA, Brasil / Weil Medical College of Cornell University. New York, USAGonçalo Moniz Research Center. Department of Biochemistry. Universidade Federal do Rio Grande do Norte. Natal, RN, BrasilLeptospirosis has been reported in rural areas of Brazil. However, there is limited information about the exposure risk or the risk of Leptospira infection for rural-based populations. A cross-sectional study was carried out in order to determine the prevalence and risk factors for prior Leptospira infection in a rural subsistence farming region of the state of Rio Grande do Norte, an area in which outbreaks of leptospirosis have occurred. Among 290 individuals enrolled, 44 (15.2%) had anti-Leptospira IgM antibodies as determined by IgM ELISA. Infection tended to occur with activities related to the rice fields (P=0.08). Our findings indicate that Leptospira infection occurs even in years of low rainfall, and may have an important impact among poor rural-based subsistence farmers in Brazil. Additional studies are needed to characterize the mode of transmission in this region

Global variation in postoperative mortality and complications after cancer surgery: a multicentre, prospective cohort study in 82 countries

© 2021 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY-NC-ND 4.0 licenseBackground: 80% of individuals with cancer will require a surgical procedure, yet little comparative data exist on early outcomes in low-income and middle-income countries (LMICs). We compared postoperative outcomes in breast, colorectal, and gastric cancer surgery in hospitals worldwide, focusing on the effect of disease stage and complications on postoperative mortality. Methods: This was a multicentre, international prospective cohort study of consecutive adult patients undergoing surgery for primary breast, colorectal, or gastric cancer requiring a skin incision done under general or neuraxial anaesthesia. The primary outcome was death or major complication within 30 days of surgery. Multilevel logistic regression determined relationships within three-level nested models of patients within hospitals and countries. Hospital-level infrastructure effects were explored with three-way mediation analyses. This study was registered with ClinicalTrials.gov, NCT03471494. Findings: Between April 1, 2018, and Jan 31, 2019, we enrolled 15 958 patients from 428 hospitals in 82 countries (high income 9106 patients, 31 countries; upper-middle income 2721 patients, 23 countries; or lower-middle income 4131 patients, 28 countries). Patients in LMICs presented with more advanced disease compared with patients in high-income countries. 30-day mortality was higher for gastric cancer in low-income or lower-middle-income countries (adjusted odds ratio 3·72, 95% CI 1·70–8·16) and for colorectal cancer in low-income or lower-middle-income countries (4·59, 2·39–8·80) and upper-middle-income countries (2·06, 1·11–3·83). No difference in 30-day mortality was seen in breast cancer. The proportion of patients who died after a major complication was greatest in low-income or lower-middle-income countries (6·15, 3·26–11·59) and upper-middle-income countries (3·89, 2·08–7·29). Postoperative death after complications was partly explained by patient factors (60%) and partly by hospital or country (40%). The absence of consistently available postoperative care facilities was associated with seven to 10 more deaths per 100 major complications in LMICs. Cancer stage alone explained little of the early variation in mortality or postoperative complications. Interpretation: Higher levels of mortality after cancer surgery in LMICs was not fully explained by later presentation of disease. The capacity to rescue patients from surgical complications is a tangible opportunity for meaningful intervention. Early death after cancer surgery might be reduced by policies focusing on strengthening perioperative care systems to detect and intervene in common complications. Funding: National Institute for Health Research Global Health Research Unit

Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

© 2022 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 licenseBackground: Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide. Methods: A multimethods analysis was performed as part of the GlobalSurg 3 study—a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital. Findings: Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3·85 [95% CI 2·58–5·75]; p<0·0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63·0% vs 82·7%; OR 0·35 [0·23–0·53]; p<0·0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer. Interpretation: Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised. Funding: National Institute for Health and Care Research