The present study shows that double-stranded RNA-dependent protein kinase （PKR） regulates the protein expres- sion level and phosphorylation of Bcl-2 and plays an anti-apoptotic role in human hepatocellular carcinom...The present study shows that double-stranded RNA-dependent protein kinase （PKR） regulates the protein expres- sion level and phosphorylation of Bcl-2 and plays an anti-apoptotic role in human hepatocellular carcinoma ceils （HepG2）. In various types of cells, saturated free fatty acids （FFAs）, such as palmitate, have been shown to induce cellular apoptosis by several mechanisms. Palmitate down-regulates the activity of PKR and thereby decreases the level of Bcl-2 protein, mediated in part by reduced activation of the NF-KB transcription factor. In addition to the level of Bel-2 protein, the phosphorylation of Bcl-2 at different amino acid residues, such as Ser70 and Ser87, is also important in regulating cellular apoptosis. The decrease in the phosphorylatiou of Bcl-2 at Ser70 upon exposure to palmitate is mediated by inhibition of PKR and possibly by c-Jun N-terminal kinase （JNK）, whereas the phosphory- lation of Bcl-2 at Ser87 is unaffected by palmitate or PKR. In summary, PKR mediates the regulation of the protein level and the phosphorylation status of Bel-2, providing a novel mechanism of palmitate-induced apoptosis in HepG2 cells.展开更多
The objective of this research was to develop a catalyst for efficient cracking of palm oil to produce biogasoline. Mesoporous alumino-silicate, A1MCM-41, was synthesized by hydrothermal treatment to the mixture of so...The objective of this research was to develop a catalyst for efficient cracking of palm oil to produce biogasoline. Mesoporous alumino-silicate, A1MCM-41, was synthesized by hydrothermal treatment to the mixture of sodium silicate, sodium aluminates, TMAOH （tetramethylammonium hydroxide）, and CTMAB （cetyltrimethylammonium bromide）, in Aquadest as a solvent. This process was carried out within 12 h of aging time at 100 ℃ in a teflon-lined stainless steel autoclave. The solid phase was filtered, then washed with distilled water, and dried in an oven at 80 ℃ for 24 h. The surfactant CTMAB was removed by calcination at 540 ℃ for 6 h using heating rate of 2 ℃/min. The as-synthesized and calcined powder was characterized by using FTIR （frontier transform infra red spectroscopy）, XRD （X-ray diffraction）, and TEM （transmission electron microscopy） methods. The product of AIMCM-41 was then converted into H-AIMCM-41 by ion exchanged in 0.5 M of NHaCI solution followed by filtration, drying at 80 ℃ for 24 h, and calcination at 540 ℃. The product of catalyst was used for catalytic conversion of PO （palm oil） to biogasoline in a fixed bed reactor at 200-400 ℃, under atmospheric pressure, and ratio of PO to catalyst was 200. The product of cracking was then distilled at 60 ℃ and analyzed using GC-MS （gas liquid chromatography - mass spectrometry） method. Result of the works shows that the catalyst had 4.49 nm of lattice parameter, and the cracking of PO gave 56.6% conversions with 29.4% selectivity to biogasoline like fraction.展开更多
文摘The present study shows that double-stranded RNA-dependent protein kinase （PKR） regulates the protein expres- sion level and phosphorylation of Bcl-2 and plays an anti-apoptotic role in human hepatocellular carcinoma ceils （HepG2）. In various types of cells, saturated free fatty acids （FFAs）, such as palmitate, have been shown to induce cellular apoptosis by several mechanisms. Palmitate down-regulates the activity of PKR and thereby decreases the level of Bcl-2 protein, mediated in part by reduced activation of the NF-KB transcription factor. In addition to the level of Bel-2 protein, the phosphorylation of Bcl-2 at different amino acid residues, such as Ser70 and Ser87, is also important in regulating cellular apoptosis. The decrease in the phosphorylatiou of Bcl-2 at Ser70 upon exposure to palmitate is mediated by inhibition of PKR and possibly by c-Jun N-terminal kinase （JNK）, whereas the phosphory- lation of Bcl-2 at Ser87 is unaffected by palmitate or PKR. In summary, PKR mediates the regulation of the protein level and the phosphorylation status of Bel-2, providing a novel mechanism of palmitate-induced apoptosis in HepG2 cells.
文摘The objective of this research was to develop a catalyst for efficient cracking of palm oil to produce biogasoline. Mesoporous alumino-silicate, A1MCM-41, was synthesized by hydrothermal treatment to the mixture of sodium silicate, sodium aluminates, TMAOH （tetramethylammonium hydroxide）, and CTMAB （cetyltrimethylammonium bromide）, in Aquadest as a solvent. This process was carried out within 12 h of aging time at 100 ℃ in a teflon-lined stainless steel autoclave. The solid phase was filtered, then washed with distilled water, and dried in an oven at 80 ℃ for 24 h. The surfactant CTMAB was removed by calcination at 540 ℃ for 6 h using heating rate of 2 ℃/min. The as-synthesized and calcined powder was characterized by using FTIR （frontier transform infra red spectroscopy）, XRD （X-ray diffraction）, and TEM （transmission electron microscopy） methods. The product of AIMCM-41 was then converted into H-AIMCM-41 by ion exchanged in 0.5 M of NHaCI solution followed by filtration, drying at 80 ℃ for 24 h, and calcination at 540 ℃. The product of catalyst was used for catalytic conversion of PO （palm oil） to biogasoline in a fixed bed reactor at 200-400 ℃, under atmospheric pressure, and ratio of PO to catalyst was 200. The product of cracking was then distilled at 60 ℃ and analyzed using GC-MS （gas liquid chromatography - mass spectrometry） method. Result of the works shows that the catalyst had 4.49 nm of lattice parameter, and the cracking of PO gave 56.6% conversions with 29.4% selectivity to biogasoline like fraction.
