Synthesis, Structure, and Antimicrobial Performance of Ni_xZn_1−xFe₂O₄ (x = 0, 0.3, 0.7, 1.0) Magnetic Powders toward <i>E. coli</i>, <i>B. cereus</i>, <i>S. citreus</i>, and <i>C. tropicalis</i>

The active development of water purification functional materials based on multicomponent spinel ferrites makes it necessary to search for new efficient methods of obtaining initial nanostructured powders. In this study, a two-stage method for the synthesis of perspective pollutant absorption agents based on NixZn1−xFe2O4 (x = 0, 0.3, 0.7, 1.0) spinel ferrites are proposed and implemented. The approach is based on the synthesis of the initial powder using the solution combustion method and its subsequent thermal treatment in the air. It was found that synthesized samples are single-phase Ni-Zn ferrites with an average crystallite size of 41.4 to 35.7 nm and a degree of crystallinity of ~95–96%. The analysis of antimicrobial activity against four diverse test-cultures: Escherichia coli ATCC 11229 (non-spore-forming gram-negative), Bacillus cereus ATCC 10702 (spore-forming gram-positive), Staphylococcus citreus NCTC 9379 (non-spore-forming gram-positive), and Candida tropicalis ATCC 750 (yeast) showed that almost all of the synthesized powders exhibit an advanced ability to inhibit the growth of the microorganisms mentioned above. The compositions obtained can be a perspective basis for both natural and wastewater purificators with magnetic separation ability and can find biotechnological and biomedical applications as promising antimicrobial materials

Synthesis, Structure, and Antimicrobial Performance of NixZn1&minus;xFe2O4 (x = 0, 0.3, 0.7, 1.0) Magnetic Powders toward E. coli, B. cereus, S. citreus, and C. tropicalis

The active development of water purification functional materials based on multicomponent spinel ferrites makes it necessary to search for new efficient methods of obtaining initial nanostructured powders. In this study, a two-stage method for the synthesis of perspective pollutant absorption agents based on NixZn1&minus;xFe2O4 (x = 0, 0.3, 0.7, 1.0) spinel ferrites are proposed and implemented. The approach is based on the synthesis of the initial powder using the solution combustion method and its subsequent thermal treatment in the air. It was found that synthesized samples are single-phase Ni-Zn ferrites with an average crystallite size of 41.4 to 35.7 nm and a degree of crystallinity of ~95&ndash;96%. The analysis of antimicrobial activity against four diverse test-cultures: Escherichia coli ATCC 11229 (non-spore-forming gram-negative), Bacillus cereus ATCC 10702 (spore-forming gram-positive), Staphylococcus citreus NCTC 9379 (non-spore-forming gram-positive), and Candida tropicalis ATCC 750 (yeast) showed that almost all of the synthesized powders exhibit an advanced ability to inhibit the growth of the microorganisms mentioned above. The compositions obtained can be a perspective basis for both natural and wastewater purificators with magnetic separation ability and can find biotechnological and biomedical applications as promising antimicrobial materials

The Influence of Co-Precipitation Technique on the Structure, Morphology and Dual-Modal Proton Relaxivity of GdFeO3 Nanoparticles

Nanocrystals of gadolinium orthoferrite (GdFeO3) with morphology close to isometric and superparamagnetic behavior were successfully synthesized using direct, reverse and microreactor co-precipitation of gadolinium and iron(III) hydroxides with their subsequent heat treatment in the air. The obtained samples were investigated by PXRD, FTIR, low-temperature nitrogen adsorption-desorption measurements, HRTEM, SAED, DRS and vibration magnetometry. According to the X-ray diffraction patterns, the GdFeO3 nanocrystals obtained using direct co-precipitation have the smallest average size, while the GdFeO3 nanocrystals obtained using reverse and microreactor co-precipitation have approximately the same average size. It was shown that the characteristic particle size values are much larger than the corresponding values of the average crystallite size, which indicates the aggregation of the obtained GdFeO3 nanocrystals. The GdFeO3 nanocrystals obtained using direct co-precipitation aggregate more than the GdFeO3 nanocrystals obtained using reverse co-precipitation, which, in turn, tend to aggregate more strongly than the GdFeO3 nanocrystals obtained using microreactor co-precipitation. The bandgap of the obtained GdFeO3 nanocrystals decreases with decreasing crystallite size, which is apparently due to their aggregation. The colloidal solutions of the obtained GdFeO3 nanocrystals with different concentrations were investigated by 1H NMR to measure the T1 and T2 relaxation times. Based on the obtained r2/r1 ratios, the GdFeO3 nanocrystals obtained using microreactor, direct and reverse co-precipitation may be classified as T1, T2 and T1–T2 dual-modal MRI contrast agents, respectively

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

Critical care admission following elective surgery was not associated with survival benefit: prospective analysis of data from 27 countries

This was an investigator initiated study funded by Nestle Health Sciences through an unrestricted research grant, and by a National Institute for Health Research (UK) Professorship held by RP. The study was sponsored by Queen Mary University of London