AlN powders were synthesized by carbothermal reduction method from aluminum nitrate and glucose. The effect of urea on the preparation and nitridation of the precursors was studied. It is found that urea can affect th...AlN powders were synthesized by carbothermal reduction method from aluminum nitrate and glucose. The effect of urea on the preparation and nitridation of the precursors was studied. It is found that urea can affect the morphology and composition of the precursor as well as the nitridation process. During the nitridation process of the precursor prepared without urea, α-Al 2O 3 and AlON are detected and a high temperature(1 600 ℃) is needed for a complete conversion. While for the precursor prepared with urea, a complete conversion is got at a relatively low temperature(1 400 ℃) and AlN is synthesized directly from γ-Al 2O 3, with no sign of the formation of α-Al 2O 3 and AlON. AlN powders synthesized from the precursor prepared without urea agglomerate badly, while the powders synthesized from the precursor prepared with urea are soft aggregates of fine particle, which can be easily dispersed.展开更多
Objective: To investigate the neuroprotective effects of Syzygium aromaticum(S.aromaticum)extract(500 mg/kg) on AlCl_3(300 mg/kg)-induced mouse model of oxidative stress and neurotoxicity.Methods: An ethanolic extract...Objective: To investigate the neuroprotective effects of Syzygium aromaticum(S.aromaticum)extract(500 mg/kg) on AlCl_3(300 mg/kg)-induced mouse model of oxidative stress and neurotoxicity.Methods: An ethanolic extract of S.aromaticum seeds was prepared and the active compounds were identified using nuclear magnetic resonance spectroscopy.BALB/c mice were divided into five groups(negative control, AlCl_3-treated, self-recovery, AlCl_3 + S.aromaticum, S.aromaticum only; n=10) and treated with AlCl_3 and S.aromaticum extract.Expression of oxidative markers [Superoxide dismutase 1(SOD1) and peroxiredoxin 6(Prdx6)] and amyloid precursor protein(APP) in the hippocampus and cortex was evaluated via PCR.Histopathological assessment was performed to investigate the extent of neurodegeneration.Results: It was observed that AlCl_3 exposure increased the expression of APP770 while simultaneously down regulated the expression of APP695.AlCl_3 also induced a significant decrease(P<0.05) and an increase(P<0.05) in the expression level of SOD1 and Prdx6, respectively.A substantial decrease substantial(P<0.05) in the density of Nissl substance was also observed in cortex of the mice treated with AlCl_3.Interestingly, treatment with S.aromaticum extract normalized the alterations in the expression level of SOD1, Prdx6 and APPisoforms and improved the neuronal structural damage.Conclusions: The results showed that S.aromaticum is a promising antioxidant and a neuroprotective agent.展开更多
文摘AlN powders were synthesized by carbothermal reduction method from aluminum nitrate and glucose. The effect of urea on the preparation and nitridation of the precursors was studied. It is found that urea can affect the morphology and composition of the precursor as well as the nitridation process. During the nitridation process of the precursor prepared without urea, α-Al 2O 3 and AlON are detected and a high temperature(1 600 ℃) is needed for a complete conversion. While for the precursor prepared with urea, a complete conversion is got at a relatively low temperature(1 400 ℃) and AlN is synthesized directly from γ-Al 2O 3, with no sign of the formation of α-Al 2O 3 and AlON. AlN powders synthesized from the precursor prepared without urea agglomerate badly, while the powders synthesized from the precursor prepared with urea are soft aggregates of fine particle, which can be easily dispersed.
基金supported by research grant by National University of Sciences and Technology (NUST), Islamabad, Pakistan
文摘Objective: To investigate the neuroprotective effects of Syzygium aromaticum(S.aromaticum)extract(500 mg/kg) on AlCl_3(300 mg/kg)-induced mouse model of oxidative stress and neurotoxicity.Methods: An ethanolic extract of S.aromaticum seeds was prepared and the active compounds were identified using nuclear magnetic resonance spectroscopy.BALB/c mice were divided into five groups(negative control, AlCl_3-treated, self-recovery, AlCl_3 + S.aromaticum, S.aromaticum only; n=10) and treated with AlCl_3 and S.aromaticum extract.Expression of oxidative markers [Superoxide dismutase 1(SOD1) and peroxiredoxin 6(Prdx6)] and amyloid precursor protein(APP) in the hippocampus and cortex was evaluated via PCR.Histopathological assessment was performed to investigate the extent of neurodegeneration.Results: It was observed that AlCl_3 exposure increased the expression of APP770 while simultaneously down regulated the expression of APP695.AlCl_3 also induced a significant decrease(P<0.05) and an increase(P<0.05) in the expression level of SOD1 and Prdx6, respectively.A substantial decrease substantial(P<0.05) in the density of Nissl substance was also observed in cortex of the mice treated with AlCl_3.Interestingly, treatment with S.aromaticum extract normalized the alterations in the expression level of SOD1, Prdx6 and APPisoforms and improved the neuronal structural damage.Conclusions: The results showed that S.aromaticum is a promising antioxidant and a neuroprotective agent.
