BACKGROUND  The safety of training in off-pump coronary artery bypass (OPCAB) surgery and the stage at which trainees should be exposed to this technique remain controversial. This single-center retrospective study aimed to compare outcomes of OPCAB surgery in consultant and trainee cases. METHODS  Between 2014 and 2018, all isolated OPCAB operations performed under the care of a consultant surgeon (G.A.) were analyzed. Cases where a surgeon below consultant grade performed at least 70% of the distal anastomoses were designated as "trainee cases" with the remaining cases designated as "consultant cases." The baseline characteristics of patients, perioperative data, and short-term outcomes were prospectively collated and analyzed. RESULTS  During the study period, 245 OPCAB cases were identified 142 (58%) consultant and 103 (42%) trainee cases. The trainee cases were performed exclusively by trainees in the final 2 years of the UK National Cardiothoracic Training Program. Both trainee and consultant groups had low mortality with two perioperative deaths occurring in either group. The rates of serious postoperative complications including stroke (n = 1 vs. 2, p = 0.759), resternotomy for bleeding (n = 3 vs.  https://www.selleckchem.com/products/h-1152-dihydrochloride.html  7, p = 0.431), and mediastinal infection (n = 2 vs. 3, p = 0.926) were low and not significantly different between the two groups. Patients operated on by trainees had a slightly longer hospital stay than those operated on by the consultant surgeon, although this did not reach statistical significance (9.9 vs. 7.9 days). CONCLUSIONS  These results demonstrate comparable outcomes in OPCAB surgery between a consultant surgeon and trainees. This study supports the conclusion that training surgeons in OPCAB is appropriate for trainees in the final years of cardiac surgery training. Georg Thieme Verlag KG Stuttgart · New York.This study investigated the effect of supplementing nano-sized magnetite (Fe3O4 NPs), multi-wall carbon nanotubes (MWCNTs) and Fe3O4-MWCNTs composite on bioconversion of waste activated sludge to hydrogen, in batch systems. Substrate degradation efficiency (SDE) increased from 28 ± 3.8 (control) to 49 ± 5.9, 46 ± 4.8 and 52 ± 6.3% at optimal doses of 200 (Fe3O4 NPs), 300 (MWCNTs) and 200 mg/L (Fe3O4-MWCNTs), respectively. Based on dissolved iron and sludge conductivity measurements, superior SDE in Fe3O4 and MWCNTs batches have been assigned to enhanced dissimilatory iron reduction (DIR) and high sludge conductivity, respectively. Combined impacts for sludge conductivity and DIR were revealed in Fe3O4-MWCNTs system. In 200 mg/L (Fe3O4-MWCNTs) batch, catalytic activities of hydrogenase, protease and α-amylase peaked to 596, 146 and 131% (relative to control), respectively; as well as, highest volumetric H2 production of 607 ± 59 mL/L was acquired. Performance deteriorations at high concentrations of nanoparticles were caused by cellular oxidative stress induced by generated reactive oxygen species. The effect of single walled carbon nanotubes (SWCNT) on methane production under high acetate concentration and thermophilic condition was evaluated. An isotope labeling experiment verified that >85% of methane was generated from syntrophic acetate oxidation (SAO) at 50, 100 and 150 mM acetate and almost 100% at 200 mM. SWCNT addition had little effect on the methanogenesis pathway, whereas it accelerated methane production via decreasing lag phase times and increasing maximum methane production rates. Electrochemical impedance spectroscopy (EIS) results revealed the electrical resistivity of sludge in groups of SWCNT was distinctly smaller than CK groups, indicating higher sludge conductivity was achieved. Further, the results of communities described that Coprothermobacter and Thermacetogenium played the most important role in SAO under all conditions. Meanwhile, the enriched Thermacetogenium and direct interspecies electron transfer (DIET) pathway in SAO consortia contributed to the acceleration of methane production via SWCNT addition. The performance, microbial communities and functional gene metabolism of the novel microbial fuel cell (MFC)-granular sludge coupling system was investigated. The results showed that COD and nitrogen removal can be up to 1.3-2.0 kg COD/L, 20-30 mg NO2--N/L, and 60-70 mg NO3--N/L, respectively. Proteobacteria, Chloroflexi, and Firmicutes were the dominant bacterial phyla, and the denitrification process was mainly consisted of the dominant denitrifying bacteria Thauera (26.21%) and Pseudomonas (14.79%) in the first compartment, combining with denitrifying anaerobic methane oxidation bacteria NC10 phylum of 0.072% (the first compartment) and 0.089% (the fourth compartment), Candidatus Methylomirabilis oxyfera of 0.044% (the first compartment) and 0.048% (the fourth compartment). According to functional gene classification for Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, metabolism was the main cluster for the whole sequence in the KEGG (7.17-11.41%), indicating that the dominant metabolic pathway played an important role in the degradation of pollutants. This work studied the effect of total solid (TS) of sewage sludge on VFA production and composition in anaerobic fermentation. Results revealed that VFA concentration reached the highest of 10.16 g/L and the ratio of acetic acid, propionic acid and n-butyric acid was 522 with the 8% TS sewage sludge. In subsequent chain elongation with sludge fermentation liquid, n-caproic acid concentration reached 43.45 mmol/L. The microbial community analysis indicated that relative abundance of Clostridium_sensu_stricto_12 for n-caproic acid production was high (52.41%). The chain elongation with sludge fermentation liquid had more pathways to produce n-caproic acid, and the chain elongation reactions were thermodynamically possible. The mixed VFAs and high concentration of n-butyric acid benefitted n-caproic acid production. Carbon balance revealed that the VFA composition of sludge fermentation liquid was beneficial to the chain elongation. This study will contribute to wasted sludge minimization and high-value material production.