Bulk nanocrystalline Al was fabricated by mechanically milling at cryogenic temperature （cryomilling） and then by hot pressing in vacuum. By using X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and...Bulk nanocrystalline Al was fabricated by mechanically milling at cryogenic temperature （cryomilling） and then by hot pressing in vacuum. By using X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and transmission electron microscopy （TEM）, the microstructure evolution of the material during cryomilling and consolidation was investigated. With increasing the milling time, the grain size decreased sharply and reduced to 42 nm when cryomilled for 12 h. The grains had grown up, and the columnar grain was formed under the hot pressing and extrusion compared with the cryomilled powders. The grain size of as-extruded specimen was approximately 300-500 nm. The reason of high thermal stability of this bulk was attributed primarily to the Zener pinning from the grain boundary of the AlN arising from cryomilling and the solute drag of the impurity. Tensile tests show that the strength of nanocrystalline Al is enhanced with decreasing grain size. The ultimate tensile strength and tensile elongation were 173 MPa and 17.5%, respectively. It appears that the measured high strength in the cryomilled Al is related to a grain-size effect, dispersion strengthening, and dislocation strengthening.展开更多
Parkinson's disease(PD)is the second most common neurodegenerative disease.Potassium voltage-gated channels are potential targets for the treatment of PD.The aim of this study is to identify novel potassium ion ch...Parkinson's disease(PD)is the second most common neurodegenerative disease.Potassium voltage-gated channels are potential targets for the treatment of PD.The aim of this study is to identify novel potassium ion channel blockers for the treatment of PD through transcriptomic analysis of the coral species Galaxea fascicularis.After annotation by four different databases,four peptides were selected that showed characteristics of potassium ion channel blockers.These four peptides were subjected to multiple sequence alignment and phylogenetic analysis.These four peptides were identified as of Kunitz-type peptides,are known as potassium ion channel blockers.The structures of the peptides were modeled and subjected to molecular dynamics(MD)simulation to verify their stability,which indicated that the peptide GfKuz1 showed the highest potency to block KV1.3(potassium voltagegated channel subfamily A member 3)among the reference peptides.The MD simulation of the peptide-protein complexes showed that GfKuz1 interacted with KV1.3,and was more compact and stable than the other potassium ion channel.The blocking effect was confirmed by a potassium ion bioassay.Furthermore,GfKuz1 showed no toxicity to PC-12 cells or zebrafish at concentrations up to 100μM.In addition,GfKuz1 increased the PC-12 cell viability that was reduced by 6-hydroxydopamine hydrochloride,and also down-regulated the level of reactive oxygen species and activated the Nrf2 pathway.In summary,GfKuz1 reversed PD symptoms and is a potential peptide drug prototype for PD treatment.展开更多
基金This work was financially supported by the National High-Tech Research and Development Program of China ("863" Program) (No.2002AA302502)
文摘Bulk nanocrystalline Al was fabricated by mechanically milling at cryogenic temperature （cryomilling） and then by hot pressing in vacuum. By using X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and transmission electron microscopy （TEM）, the microstructure evolution of the material during cryomilling and consolidation was investigated. With increasing the milling time, the grain size decreased sharply and reduced to 42 nm when cryomilled for 12 h. The grains had grown up, and the columnar grain was formed under the hot pressing and extrusion compared with the cryomilled powders. The grain size of as-extruded specimen was approximately 300-500 nm. The reason of high thermal stability of this bulk was attributed primarily to the Zener pinning from the grain boundary of the AlN arising from cryomilling and the solute drag of the impurity. Tensile tests show that the strength of nanocrystalline Al is enhanced with decreasing grain size. The ultimate tensile strength and tensile elongation were 173 MPa and 17.5%, respectively. It appears that the measured high strength in the cryomilled Al is related to a grain-size effect, dispersion strengthening, and dislocation strengthening.
基金supported by the China Postdoctoral Science Foundation under Grant Number 2023M731524University of Macao and funded by The Science and Technology Development Fund(FDTC)of Macao SAR(File no.0058/2019/A1 and 0016/2019/AKP)+4 种基金University of Macao(MYRG2019-00105-ICMS)The Hong Kong Polytechnic University(Project ID.P0006304)The Environmental and Conservation Fund of Hong Kong(grant no.34/2019)Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong laboratory(Guangzhou)(grant nos.GMl2019ZD0404,SMSEGl20SC02)This work was performed in part at the high performance computing cluster(HPCC)which is supported by the Information and Communication Technology office(ICTO)of the University of Macao.
文摘Parkinson's disease(PD)is the second most common neurodegenerative disease.Potassium voltage-gated channels are potential targets for the treatment of PD.The aim of this study is to identify novel potassium ion channel blockers for the treatment of PD through transcriptomic analysis of the coral species Galaxea fascicularis.After annotation by four different databases,four peptides were selected that showed characteristics of potassium ion channel blockers.These four peptides were subjected to multiple sequence alignment and phylogenetic analysis.These four peptides were identified as of Kunitz-type peptides,are known as potassium ion channel blockers.The structures of the peptides were modeled and subjected to molecular dynamics(MD)simulation to verify their stability,which indicated that the peptide GfKuz1 showed the highest potency to block KV1.3(potassium voltagegated channel subfamily A member 3)among the reference peptides.The MD simulation of the peptide-protein complexes showed that GfKuz1 interacted with KV1.3,and was more compact and stable than the other potassium ion channel.The blocking effect was confirmed by a potassium ion bioassay.Furthermore,GfKuz1 showed no toxicity to PC-12 cells or zebrafish at concentrations up to 100μM.In addition,GfKuz1 increased the PC-12 cell viability that was reduced by 6-hydroxydopamine hydrochloride,and also down-regulated the level of reactive oxygen species and activated the Nrf2 pathway.In summary,GfKuz1 reversed PD symptoms and is a potential peptide drug prototype for PD treatment.
