Early quantitative coronary angiography of saphenous vein grafts for coronary artery bypass grafting harvested by means of open versus endoscopic saphenectomy: a prospective randomized trial

AbstractObjectiveEndoscopic saphenectomy is associated with a decreased incidence of wound complications without an increase in histologic trauma or endothelial dysfunction in published reports. Concern remains about the patency of saphenous vein grafts harvested endoscopically and the development of early intimal hyperplasia. The purpose of this study was to compare early quantitative coronary analysis of saphenous vein grafts used for coronary artery bypass grafting harvested with the open versus endoscopic techniques.MethodsForty patients undergoing primary coronary artery bypass grafting surgery with at least 1 saphenous vein graft were randomized preoperatively to open versus endoscopic saphenectomy with bipolar cauterization of side branches. Quantitative coronary angiography was performed a mean of 3 months (range, 1-9 months) after the operation.ResultsThere was no statistically significant difference in the patency rates of internal thoracic artery grafts between the open and endoscopic groups and no statistically significant difference in the patency rates of saphenous vein grafts between both groups (85.2% vs 84.4%, P = .991). Quantitative coronary angiography showed no difference in graft stenosis (≥50% of the internal diameter of the graft) in the body of the saphenous vein grafts in the open versus endoscopic saphenectomy groups (3.7% vs 0%, P = .280).ConclusionAngiographic appearance and patency rates of saphenous vein grafts harvested with the endoscopic technique are similar to those of saphenous vein grafts harvested with the open technique. These results support the use of endoscopic saphenectomy because of the known lower incidence of wound and infectious complications and superior functional results

Above-ground biomass and structure of 260 African tropical forests.

We report above-ground biomass (AGB), basal area, stem density and wood mass density estimates from 260 sample plots (mean size: 1.2 ha) in intact closed-canopy tropical forests across 12 African countries. Mean AGB is 395.7 Mg dry mass ha⁻¹ (95% CI: 14.3), substantially higher than Amazonian values, with the Congo Basin and contiguous forest region attaining AGB values (429 Mg ha⁻¹) similar to those of Bornean forests, and significantly greater than East or West African forests. AGB therefore appears generally higher in palaeo- compared with neotropical forests. However, mean stem density is low (426 ± 11 stems ha⁻¹ greater than or equal to 100 mm diameter) compared with both Amazonian and Bornean forests (cf. approx. 600) and is the signature structural feature of African tropical forests. While spatial autocorrelation complicates analyses, AGB shows a positive relationship with rainfall in the driest nine months of the year, and an opposite association with the wettest three months of the year; a negative relationship with temperature; positive relationship with clay-rich soils; and negative relationships with C : N ratio (suggesting a positive soil phosphorus-AGB relationship), and soil fertility computed as the sum of base cations. The results indicate that AGB is mediated by both climate and soils, and suggest that the AGB of African closed-canopy tropical forests may be particularly sensitive to future precipitation and temperature changes

Characterization of sunflower husks fouling in a Drop Tube Furnace: comparison of deposits with H3PO4, CaCO3 and Al2Si2O5(OH)4 additives

Fouling of heat exchangers in biomass combustion plants is an operational problem that can lead to a severe decrease of boilers efficiency and availability. To counteract deposition, additives are used to bind the vaporized alkali in high melting temperature structures, such as solid phosphates or aluminum-silicates. Fouling during the combustion of sunflower husks with a combination of P-and Ca-based additive (H 3 PO 4 and CaCO 3) and Al-silicates additives (kaolin or halloysite) was studied in a test campaign in a Drop Tube Furnace. Fouling tests with additives were compared with reference experiments with the raw fuel (two tests). Thermodynamic equilibrium computations with FactSage 7.0 and state-of-the-art databases were applied to quantify the ash molten fraction at 900°C, the mass of liquid per kg of biomass, the K-release rate to the gas phase and finally the condensed mass at 200°C. The use of additives decreased Cl and P (apart from the test with P addition) concentrations in the inner deposits and increased the amount of loose deposits on the probe. When computing the enrichment factors of the deposits with respect to the ash injected, K concentration in RAW1 deposits, with respect to RAW1 ash, is enriched of 14% (mol/mol). When using the P+Ca additive, K is depleted in deposits by 46%. With the use of aluminum-silicate additives, K is enriched by 4% for the HAL deposit and depleted of 21% for the KAO case

Characterization of sunflower husks fouling in a drop tube furnace: Comparison of deposits with H3PO4, CaCO3and Al2Si2O5(OH)4 additives

Fouling of heat exchangers in biomass combustion plants is an operational problem that can lead to a severe decrease of boilers efficiency and availability. To counteract deposition, additives are used to bind the vaporized alkali in high melting temperature structures, such as solid phosphates or aluminum-silicates. Fouling during the combustion of sunflower husks with a combination of P- and Ca-based additive (H3PO4and CaCO3) and Al-silicates additives (kaolin or halloysite) was studied in a test campaign in a Drop Tube Furnace. Fouling tests with additives were compared with reference experiments with the raw fuel (two tests). Thermodynamic equilibrium computationswith FactSage 7.0 and state-of-the-art databases were applied to quantifythe ash molten fractionat 900°C, the mass of liquid per kg of biomass, the K-release rate to the gas phase and finally the condensed mass at 200°C.The use of additives decreased Cl and P (apart from the test with P addition) concentrations in the inner deposits and increased the amount of loose deposits on the probe. When computing the enrichment factors of the deposits with respect to the ash injected, K concentration in RAW1 deposits, with respect to RAW1 ash, is enriched of 14% (mol/mol). When using the P+Ca additive, K is depleted in deposits by 46%. With the use of aluminumsilicate additives, K is enriched by 4% for the HAL deposit and depleted of 21% for the KAO case. © 2016 ETA-Florence Renewable Energies