Poly(ethylene glycol-co-1,4-cyclohexanedimethanol terephthalate)(PETG)possesses excellent properties and stability than traditional poly(ethylene terephthalate)(PET).However,the production and application of PETG are ...Poly(ethylene glycol-co-1,4-cyclohexanedimethanol terephthalate)(PETG)possesses excellent properties and stability than traditional poly(ethylene terephthalate)(PET).However,the production and application of PETG are restricted by the expensive monomer(1,4-cyclohexanedimethanol,CHDM).Direct upgrading of waste PET to dimethyl cyclohexane-1,4-dicarboxylate(DMCD)can promote the production of CHDM in large scale.In this work,a bifunctional Ru/UiO-66_(def)-SO_(3)H catalyst was synthesized and utilized in coupled methanolysis(of waste PET to dimethyl terephthalate(DMT))and hydrogenation(of DMT to DMCD)under mild condition.Characterizations revealed that Ru/UiO-66_(def)-SO_(3)H possessed mesopores(dominant channels of 2.72 and 3.44 nm),enlarged surface area(998 m^(2)·g^(–1)),enhanced acidity(580μmol·g^(–1)),and Ru nanoparticles(NPs)dispersed highly(45.1%)compared to those of Ru/UiO-66.These combined advantages could accelerate the methanolysis and hydrogenation reactions simultaneously,promoting the performance of direct upgrading of PET to DMCD in one pot.In particular,the conversion of PET and yield of DMCD over Ru/UiO-66_(def)-SO_(3)H reached 100%and 97.7%at 170℃and 3 MPa H_(2)within 6 h.Moreover,Ru/UiO-66_(def)-SO3H was also capable for the upcycling of waste PET-based products including beverage bottles,textile fiber and packaging film to DMCD.展开更多
In low Earth orbit(LEO)satellite networks,on-board energy resources of each satellite are extremely limited.And with the increase of the node number and the traffic transmis-sion pressure,the energy consumption in the...In low Earth orbit(LEO)satellite networks,on-board energy resources of each satellite are extremely limited.And with the increase of the node number and the traffic transmis-sion pressure,the energy consumption in the networks presents uneven distribution.To achieve energy balance in networks,an energy consumption balancing optimization algorithm of LEO networks based on distance energy factor(DEF)is proposed.The DEF is defined as the function of the inter-satellite link dis-tance and the cumulative network energy consumption ratio.According to the minimum sum of DEF on inter-satellite links,an energy consumption balancing algorithm based on DEF is pro-posed,which can realize dynamic traffic transmission optimiza-tion of multiple traffic services.It can effectively reduce the energy consumption pressure of core nodes with high energy consumption in the network,make full use of idle nodes with low energy consumption,and optimize the energy consumption dis-tribution of the whole network according to the continuous itera-tions of each traffic service flow.Simulation results show that,compared with the traditional shortest path algorithm,the pro-posed method can improve the balancing performance of nodes by 75%under certain traffic pressure,and realize the optimiza-tion of energy consumption balancing of the whole network.展开更多
Background: Maxillofacial war injuries usually cause severe facial organ defects and deformities, handicapping the patient's daily activities, even result in a tendency to commit suicide. The application of maxill...Background: Maxillofacial war injuries usually cause severe facial organ defects and deformities, handicapping the patient's daily activities, even result in a tendency to commit suicide. The application of maxillofacial prosthesis is an alternative to surgery in functional–aesthetic facial reconstruction. Computer aided design and computer aided manufacturing has opened up a new approach to the fabrication of maxillofacial prosthesis. An intelligentized rapid simulative design and manufacture system for prosthesis was developed to facilitate the prosthesis fabrication procedure.Methods: Maxillofacial prosthesis rapid simulation design and rapid fabrication system consists of three components: digital impression, intelligentized prosthesis designing, and rapid manufacturing. The patients' maxillofacial digital impressions were taken with Structured-light 3D scanner; and then the 3D model of prostheses and their negative molds could be designed in specific software; finally, with the resin molds fabricated by rapid prototyping machine, the prostheses could be produced directly and quickly.Results: Fifteen patients of maxillofacial defect caused by traumatic injuries received prosthesis rehabilitation provided by the established system. The contour of the prostheses coordinated properly with the appearance of the patients, and the uniform-thickness border sealed well to adjacent tissues. All the patients were satisfied with their prostheses.Conclusions: The rapid simulative rehabilitation system of maxillofacial defects has been approaching completion. It could provide advanced technological reservation for the Army in the issue of maxillofacial defect rehabilitation.展开更多
The nucleolus,as the‘nucleus of the nucleus’,is a prominent subcellular organelle in a eukaryocyte.The nucleolus serves as the centre for ribosome biogenesis,as well as an important site for cell-cycle regulation,ce...The nucleolus,as the‘nucleus of the nucleus’,is a prominent subcellular organelle in a eukaryocyte.The nucleolus serves as the centre for ribosome biogenesis,as well as an important site for cell-cycle regulation,cellular senescence,and stress response.The protein composition of the nucleolus changes dynamically through protein turnover to meet the needs of cellular activities or stress responses.Recent studies have identified a nucleolus-localized protein degradation pathway in zebrafish and humans,namely the Def-CAPN3 pathway,which is essential to ribosome production and cell-cycle progression,by controlling the turnover of multiple substrates(e.g.,ribosomal small-subunit[SSU]processome component Mpp10,transcription factor p53,check-point proteins Chk1 and Wee1).This pathway relies on the Ca2þ-dependent cysteine proteinase CAPN3 and is independent of the ubiquitin-mediated proteasome pathway.CAPN3 is recruited by nucleolar protein Def from cytoplasm to nucleolus,where it proteolyzes its substrates which harbor a CAPN3 recognition-motif.Def depletion leads to the exclusion of CAPN3 and accumulation of p53,Wee1,Chk1,and Mpp10 in the nucleolus that result in cell-cycle arrest and rRNA processing abnormality.Here,we summarize the discovery of the Def-CAPN3 pathway and propose its biological role in cell-cycle control and ribosome biogenesis.展开更多
文摘Poly(ethylene glycol-co-1,4-cyclohexanedimethanol terephthalate)(PETG)possesses excellent properties and stability than traditional poly(ethylene terephthalate)(PET).However,the production and application of PETG are restricted by the expensive monomer(1,4-cyclohexanedimethanol,CHDM).Direct upgrading of waste PET to dimethyl cyclohexane-1,4-dicarboxylate(DMCD)can promote the production of CHDM in large scale.In this work,a bifunctional Ru/UiO-66_(def)-SO_(3)H catalyst was synthesized and utilized in coupled methanolysis(of waste PET to dimethyl terephthalate(DMT))and hydrogenation(of DMT to DMCD)under mild condition.Characterizations revealed that Ru/UiO-66_(def)-SO_(3)H possessed mesopores(dominant channels of 2.72 and 3.44 nm),enlarged surface area(998 m^(2)·g^(–1)),enhanced acidity(580μmol·g^(–1)),and Ru nanoparticles(NPs)dispersed highly(45.1%)compared to those of Ru/UiO-66.These combined advantages could accelerate the methanolysis and hydrogenation reactions simultaneously,promoting the performance of direct upgrading of PET to DMCD in one pot.In particular,the conversion of PET and yield of DMCD over Ru/UiO-66_(def)-SO_(3)H reached 100%and 97.7%at 170℃and 3 MPa H_(2)within 6 h.Moreover,Ru/UiO-66_(def)-SO3H was also capable for the upcycling of waste PET-based products including beverage bottles,textile fiber and packaging film to DMCD.
基金supported by the National Key Research and Development Program(2021YFB2900604).
文摘In low Earth orbit(LEO)satellite networks,on-board energy resources of each satellite are extremely limited.And with the increase of the node number and the traffic transmis-sion pressure,the energy consumption in the networks presents uneven distribution.To achieve energy balance in networks,an energy consumption balancing optimization algorithm of LEO networks based on distance energy factor(DEF)is proposed.The DEF is defined as the function of the inter-satellite link dis-tance and the cumulative network energy consumption ratio.According to the minimum sum of DEF on inter-satellite links,an energy consumption balancing algorithm based on DEF is pro-posed,which can realize dynamic traffic transmission optimiza-tion of multiple traffic services.It can effectively reduce the energy consumption pressure of core nodes with high energy consumption in the network,make full use of idle nodes with low energy consumption,and optimize the energy consumption dis-tribution of the whole network according to the continuous itera-tions of each traffic service flow.Simulation results show that,compared with the traditional shortest path algorithm,the pro-posed method can improve the balancing performance of nodes by 75%under certain traffic pressure,and realize the optimiza-tion of energy consumption balancing of the whole network.
基金funded by National Natural Science Foundation of China (81271188)supported by National Key Technology R&D Program of China (2012BAI07B02)
文摘Background: Maxillofacial war injuries usually cause severe facial organ defects and deformities, handicapping the patient's daily activities, even result in a tendency to commit suicide. The application of maxillofacial prosthesis is an alternative to surgery in functional–aesthetic facial reconstruction. Computer aided design and computer aided manufacturing has opened up a new approach to the fabrication of maxillofacial prosthesis. An intelligentized rapid simulative design and manufacture system for prosthesis was developed to facilitate the prosthesis fabrication procedure.Methods: Maxillofacial prosthesis rapid simulation design and rapid fabrication system consists of three components: digital impression, intelligentized prosthesis designing, and rapid manufacturing. The patients' maxillofacial digital impressions were taken with Structured-light 3D scanner; and then the 3D model of prostheses and their negative molds could be designed in specific software; finally, with the resin molds fabricated by rapid prototyping machine, the prostheses could be produced directly and quickly.Results: Fifteen patients of maxillofacial defect caused by traumatic injuries received prosthesis rehabilitation provided by the established system. The contour of the prostheses coordinated properly with the appearance of the patients, and the uniform-thickness border sealed well to adjacent tissues. All the patients were satisfied with their prostheses.Conclusions: The rapid simulative rehabilitation system of maxillofacial defects has been approaching completion. It could provide advanced technological reservation for the Army in the issue of maxillofacial defect rehabilitation.
基金the National Key R&D Program of China and the Natural Science Foundation of China in the order of 2018YFA0800502,2017YFA0504501,31330050.
文摘The nucleolus,as the‘nucleus of the nucleus’,is a prominent subcellular organelle in a eukaryocyte.The nucleolus serves as the centre for ribosome biogenesis,as well as an important site for cell-cycle regulation,cellular senescence,and stress response.The protein composition of the nucleolus changes dynamically through protein turnover to meet the needs of cellular activities or stress responses.Recent studies have identified a nucleolus-localized protein degradation pathway in zebrafish and humans,namely the Def-CAPN3 pathway,which is essential to ribosome production and cell-cycle progression,by controlling the turnover of multiple substrates(e.g.,ribosomal small-subunit[SSU]processome component Mpp10,transcription factor p53,check-point proteins Chk1 and Wee1).This pathway relies on the Ca2þ-dependent cysteine proteinase CAPN3 and is independent of the ubiquitin-mediated proteasome pathway.CAPN3 is recruited by nucleolar protein Def from cytoplasm to nucleolus,where it proteolyzes its substrates which harbor a CAPN3 recognition-motif.Def depletion leads to the exclusion of CAPN3 and accumulation of p53,Wee1,Chk1,and Mpp10 in the nucleolus that result in cell-cycle arrest and rRNA processing abnormality.Here,we summarize the discovery of the Def-CAPN3 pathway and propose its biological role in cell-cycle control and ribosome biogenesis.
