Mechanical and thermal properties of the waste low and high density polyethylene-nanoclay composites

In extension with the previous work, recycling of the waste polyolefins by dissolution/reprecipitation method, has been investigated. The goal of study was to explore the influence of organo-modified/unmodified sodium montmorillonite clays, on the behaviours of waste polyolefins inclusive low density polyethylene (LDPE) and high density polyethylene (HDPE). 1-5 wt % of unmodified (MMT) and Organo-modified clay (OMMT) were added to the polyolefins, to prepare polyolefin-clay nanocomposites by melt intercalation method. X-ray diffraction (XRD) and Field Emission Scanning Electron Microscope (FESEM) were used to estimate the dispersion of clay in the polymer matrices and the morphology of nanocomposites. Thermogravimetric analysis (TGA) and Differential Scanning Calorimetry (DSC) were used to analyse the change in the thermic properties of the waste polyolefins nanocomposites. The XRD and FESEM results showed an intercalated structure in the HDPE and LDPE with Organo-clay nanocomposites, whereas no exfoliation was observed with unmodified clay in both waste HDPE and LDPE, respectively. DSC and TGA, showed an improved thermal behaviours in the HDPE/Organo-clay nanocomposites (3 wt%) clay loading. Melting temperature and crystallization percentage were observed to increase in 1, 2, and 3 wt% loadings. In waste LDPE/clay nanocomposites, no improvement was established in the thermal stability

Gas-liquid equilibrium prediction of system CO 2 -aqueous ethanol at moderate pressure and different temperatures using PR-EOS

One of the most important design considerations which should not be ignored during the equipment designing for some industrial purpose is vapour-liquid equilibrium (VLE). Thus, in chemical engineering, the first step is the computation of VLE properties of materials by employing Equation of state (EOS). In this study, we have used a thermodynamic model which was established for binary system of carbon dioxide (1)-(2) solubility of CO2 in aqueous ethanol and it was employed to estimate the gas-liquid equilibrium at moderate pressures (till 6 bar) and varying temperatures (288 K to 323 K). Peng-Robinson EOS was employed to determine the VLE properties. Mixing rules such as vanderWaals and quadratic mixing rules were also used for the determination of ethanol-water mixture critical parameters which entails the pseudo-critical method as one component and results obtained from this study were similar to the ones reported in recent literature for empirical phase equilibrium studies

Gas liquid equilibrium prediction of system (CO2-aqueous ethanol) at moderate pressure and different temperatures using PR-EOS

One of the most important design considerations which should not be ignored during the equipment designing for some industrial purpose is vapour-liquid equilibrium (VLE). Thus, in chemical engineering, the first step is the computation of VLE properties of materials by employing Equation of state (EOS). In this study, we have used a thermodynamic model which was established for binary system of carbon dioxide (1)-(2) solubility of CO2 in aqueous ethanol and it was employed to estimate the gas-liquid equilibrium at moderate pressures (till 6 bar) and varying temperatures (288 K to 323 K). Peng-Robinson EOS was employed to determine the VLE properties. Mixing rules such as vanderWaals and quadratic mixing rules were also used for the determination of ethanol-water mixture critical parameters which entails the pseudo-critical method as one component and results obtained from this study were similar to the ones reported in recent literature for empirical phase equilibrium studies

Hypomorphic variants in AK2 reveal the contribution of mitochondrial function to B-cell activation

Background The gene AK2 encodes the phosphotransferase adenylate kinase 2 (AK2). Human variants in AK2 cause reticular dysgenesis, a severe combined immunodeficiency with agranulocytosis, lymphopenia, and sensorineural deafness that requires hematopoietic stem cell transplantation for survival. Objective We investigated the mechanisms underlying recurrent sinopulmonary infections and hypogammaglobulinemia in 15 patients, ranging from 3 to 34 years of age, from 9 kindreds. Only 2 patients, both of whom had mildly impaired T-cell proliferation, each had a single clinically significant opportunistic infection. Methods Patient cells were studied with next-generation DNA sequencing, tandem mass spectrometry, and assays of lymphocyte and mitochondrial function. Results We identified 2 different homozygous variants in AK2. AK2(G100S) and AK2(A182D) permit residual protein expression, enzymatic activity, and normal numbers of neutrophils and lymphocytes. All but 1 patient had intact hearing. The patients' B cells had severely impaired proliferation and in vitro immunoglobulin secretion. With activation, the patients' B cells exhibited defective mitochondrial respiration and impaired regulation of mitochondrial membrane potential and quality. Although activated T cells from the patients with opportunistic infections demonstrated impaired mitochondrial function, the mitochondrial quality in T cells was preserved. Consistent with the capacity of activated T cells to utilize nonmitochondrial metabolism, these findings revealed a less strict cellular dependence of T-cell function on AK2 activity. Chemical inhibition of ATP synthesis in control T and B cells similarly demonstrated the greater dependency of B cells on mitochondrial function. Conclusions Our patients demonstrate the in vivo sequelae of the cell-specific requirements for the functions of AK2 and mitochondria, particularly in B-cell activation and antibody production

Geoeconomic variations in epidemiology, ventilation management, and outcomes in invasively ventilated intensive care unit patients without acute respiratory distress syndrome: a pooled analysis of four observational studies

Background: Geoeconomic variations in epidemiology, the practice of ventilation, and outcome in invasively ventilated intensive care unit (ICU) patients without acute respiratory distress syndrome (ARDS) remain unexplored. In this analysis we aim to address these gaps using individual patient data of four large observational studies. Methods: In this pooled analysis we harmonised individual patient data from the ERICC, LUNG SAFE, PRoVENT, and PRoVENT-iMiC prospective observational studies, which were conducted from June, 2011, to December, 2018, in 534 ICUs in 54 countries. We used the 2016 World Bank classification to define two geoeconomic regions: middle-income countries (MICs) and high-income countries (HICs). ARDS was defined according to the Berlin criteria. Descriptive statistics were used to compare patients in MICs versus HICs. The primary outcome was the use of low tidal volume ventilation (LTVV) for the first 3 days of mechanical ventilation. Secondary outcomes were key ventilation parameters (tidal volume size, positive end-expiratory pressure, fraction of inspired oxygen, peak pressure, plateau pressure, driving pressure, and respiratory rate), patient characteristics, the risk for and actual development of acute respiratory distress syndrome after the first day of ventilation, duration of ventilation, ICU length of stay, and ICU mortality. Findings: Of the 7608 patients included in the original studies, this analysis included 3852 patients without ARDS, of whom 2345 were from MICs and 1507 were from HICs. Patients in MICs were younger, shorter and with a slightly lower body-mass index, more often had diabetes and active cancer, but less often chronic obstructive pulmonary disease and heart failure than patients from HICs. Sequential organ failure assessment scores were similar in MICs and HICs. Use of LTVV in MICs and HICs was comparable (42·4% vs 44·2%; absolute difference -1·69 [-9·58 to 6·11] p=0·67; data available in 3174 [82%] of 3852 patients). The median applied positive end expiratory pressure was lower in MICs than in HICs (5 [IQR 5-8] vs 6 [5-8] cm H2O; p=0·0011). ICU mortality was higher in MICs than in HICs (30·5% vs 19·9%; p=0·0004; adjusted effect 16·41% [95% CI 9·52-23·52]; p<0·0001) and was inversely associated with gross domestic product (adjusted odds ratio for a US$10 000 increase per capita 0·80 [95% CI 0·75-0·86]; p<0·0001). Interpretation: Despite similar disease severity and ventilation management, ICU mortality in patients without ARDS is higher in MICs than in HICs, with a strong association with country-level economic status

Prospective observational cohort study on grading the severity of postoperative complications in global surgery research

Background The Clavien–Dindo classification is perhaps the most widely used approach for reporting postoperative complications in clinical trials. This system classifies complication severity by the treatment provided. However, it is unclear whether the Clavien–Dindo system can be used internationally in studies across differing healthcare systems in high- (HICs) and low- and middle-income countries (LMICs). Methods This was a secondary analysis of the International Surgical Outcomes Study (ISOS), a prospective observational cohort study of elective surgery in adults. Data collection occurred over a 7-day period. Severity of complications was graded using Clavien–Dindo and the simpler ISOS grading (mild, moderate or severe, based on guided investigator judgement). Severity grading was compared using the intraclass correlation coefficient (ICC). Data are presented as frequencies and ICC values (with 95 per cent c.i.). The analysis was stratified by income status of the country, comparing HICs with LMICs. Results A total of 44 814 patients were recruited from 474 hospitals in 27 countries (19 HICs and 8 LMICs). Some 7508 patients (16·8 per cent) experienced at least one postoperative complication, equivalent to 11 664 complications in total. Using the ISOS classification, 5504 of 11 664 complications (47·2 per cent) were graded as mild, 4244 (36·4 per cent) as moderate and 1916 (16·4 per cent) as severe. Using Clavien–Dindo, 6781 of 11 664 complications (58·1 per cent) were graded as I or II, 1740 (14·9 per cent) as III, 2408 (20·6 per cent) as IV and 735 (6·3 per cent) as V. Agreement between classification systems was poor overall (ICC 0·41, 95 per cent c.i. 0·20 to 0·55), and in LMICs (ICC 0·23, 0·05 to 0·38) and HICs (ICC 0·46, 0·25 to 0·59). Conclusion Caution is recommended when using a treatment approach to grade complications in global surgery studies, as this may introduce bias unintentionally

The surgical safety checklist and patient outcomes after surgery: a prospective observational cohort study, systematic review and meta-analysis

© 2017 British Journal of Anaesthesia Background: The surgical safety checklist is widely used to improve the quality of perioperative care. However, clinicians continue to debate the clinical effectiveness of this tool. Methods: Prospective analysis of data from the International Surgical Outcomes Study (ISOS), an international observational study of elective in-patient surgery, accompanied by a systematic review and meta-analysis of published literature. The exposure was surgical safety checklist use. The primary outcome was in-hospital mortality and the secondary outcome was postoperative complications. In the ISOS cohort, a multivariable multi-level generalized linear model was used to test associations. To further contextualise these findings, we included the results from the ISOS cohort in a meta-analysis. Results are reported as odds ratios (OR) with 95% confidence intervals. Results: We included 44 814 patients from 497 hospitals in 27 countries in the ISOS analysis. There were 40 245 (89.8%) patients exposed to the checklist, whilst 7508 (16.8%) sustained ≥1 postoperative complications and 207 (0.5%) died before hospital discharge. Checklist exposure was associated with reduced mortality [odds ratio (OR) 0.49 (0.32–0.77); P\u3c0.01], but no difference in complication rates [OR 1.02 (0.88–1.19); P=0.75]. In a systematic review, we screened 3732 records and identified 11 eligible studies of 453 292 patients including the ISOS cohort. Checklist exposure was associated with both reduced postoperative mortality [OR 0.75 (0.62–0.92); P\u3c0.01; I2=87%] and reduced complication rates [OR 0.73 (0.61–0.88); P\u3c0.01; I2=89%). Conclusions: Patients exposed to a surgical safety checklist experience better postoperative outcomes, but this could simply reflect wider quality of care in hospitals where checklist use is routine