Currently, in a context of sustainable development, the economic and environmental challenges incite, to valorize local materials such as clays and agro-industrial waste. It is in this approach that a new category of ...Currently, in a context of sustainable development, the economic and environmental challenges incite, to valorize local materials such as clays and agro-industrial waste. It is in this approach that a new category of compressed earth bricks (BTC) stabilized with shea meal (TK) and cement was proposed. The purpose of this paper is to investigate the effect of shea meal rate on the thermal conductivity properties of cement stabilized earth bricks. A lateritic clay (Lat) mainly composed of kaolinite (38.44%), quartz (24.94%), goethite (12.28%), hematite (4.44%) and illite (19.9%) was used to make bricks. Different mix designs made up of lateritic clay and 5% cement were studied. The shea meal is added as a partial lateritic clay replacement in different proportions. The thermal conductivity was determined by hot disk method and correlated to both porosity and density of elaborated materials. The results obtained show that the thermal conductivity and density of bricks decrease respectively from 0.72 W·m-1·K-1 to 0.52 W·m-1·K-1 and from 2.77 g·cm-3 to 2.52 g·cm-3. The presence of shea meal within the material generates pore formation, which may partly explain the improvement of the thermal insulation properties. A positive correlation was noted between density and thermal conductivity of these materials.展开更多
From (2,3-dihydro-1<i>H</i>-perimidin-2-yl)-phenyl, the substitution of OH group in <i>ortho</i> or <i>para</i> position on the phenyl ring, allows us to synthesize the studied comp...From (2,3-dihydro-1<i>H</i>-perimidin-2-yl)-phenyl, the substitution of OH group in <i>ortho</i> or <i>para</i> position on the phenyl ring, allows us to synthesize the studied compounds. These three compounds have been characterized by conventional spectroscopic methods (NMR and MS). The interest of this work is to review the antioxidant activity of our compounds. The antioxidant activity screening carried out according to FRAP and DPPH methods revealed significant anti-free radical properties for compounds 1 and 2 even at low concentrations. In contrast to the compound 2, compound 3 for which the OH group is substituted in <i>para</i> position has the lowest activity in both cases. Therefore the <i>para</i> position seems to be the least sensitive position to increase the antioxidant activity of this pharmacophore.展开更多
A new flavonoid, acacetin-7-O-β-D-glucopyranosyl-(1 → 2)-β-D-glucuronopyranoside (1), together with four known flavonoids, apigenin-7-O-β-D-glucopyranosyl-(1 → 2)-β-D-glucuronopyranoside (2), acacetin (3), acace...A new flavonoid, acacetin-7-O-β-D-glucopyranosyl-(1 → 2)-β-D-glucuronopyranoside (1), together with four known flavonoids, apigenin-7-O-β-D-glucopyranosyl-(1 → 2)-β-D-glucuronopyranoside (2), acacetin (3), acacetin-7-O-β-D-glucuronide (4) and genkwanin-5-O-primveroside (5) were isolated from the leaves of Glyphaea brevis. Their structures were elucidated by spectroscopic techniques. The isolated compounds (1 - 5) were tested for their antioxidant activity using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay. The tested compounds showed slight negative antioxidant activities against DPPH radicals.展开更多
文摘Currently, in a context of sustainable development, the economic and environmental challenges incite, to valorize local materials such as clays and agro-industrial waste. It is in this approach that a new category of compressed earth bricks (BTC) stabilized with shea meal (TK) and cement was proposed. The purpose of this paper is to investigate the effect of shea meal rate on the thermal conductivity properties of cement stabilized earth bricks. A lateritic clay (Lat) mainly composed of kaolinite (38.44%), quartz (24.94%), goethite (12.28%), hematite (4.44%) and illite (19.9%) was used to make bricks. Different mix designs made up of lateritic clay and 5% cement were studied. The shea meal is added as a partial lateritic clay replacement in different proportions. The thermal conductivity was determined by hot disk method and correlated to both porosity and density of elaborated materials. The results obtained show that the thermal conductivity and density of bricks decrease respectively from 0.72 W·m-1·K-1 to 0.52 W·m-1·K-1 and from 2.77 g·cm-3 to 2.52 g·cm-3. The presence of shea meal within the material generates pore formation, which may partly explain the improvement of the thermal insulation properties. A positive correlation was noted between density and thermal conductivity of these materials.
文摘From (2,3-dihydro-1<i>H</i>-perimidin-2-yl)-phenyl, the substitution of OH group in <i>ortho</i> or <i>para</i> position on the phenyl ring, allows us to synthesize the studied compounds. These three compounds have been characterized by conventional spectroscopic methods (NMR and MS). The interest of this work is to review the antioxidant activity of our compounds. The antioxidant activity screening carried out according to FRAP and DPPH methods revealed significant anti-free radical properties for compounds 1 and 2 even at low concentrations. In contrast to the compound 2, compound 3 for which the OH group is substituted in <i>para</i> position has the lowest activity in both cases. Therefore the <i>para</i> position seems to be the least sensitive position to increase the antioxidant activity of this pharmacophore.
文摘A new flavonoid, acacetin-7-O-β-D-glucopyranosyl-(1 → 2)-β-D-glucuronopyranoside (1), together with four known flavonoids, apigenin-7-O-β-D-glucopyranosyl-(1 → 2)-β-D-glucuronopyranoside (2), acacetin (3), acacetin-7-O-β-D-glucuronide (4) and genkwanin-5-O-primveroside (5) were isolated from the leaves of Glyphaea brevis. Their structures were elucidated by spectroscopic techniques. The isolated compounds (1 - 5) were tested for their antioxidant activity using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay. The tested compounds showed slight negative antioxidant activities against DPPH radicals.
