Parkinson’s disease(PD)is a common neurodegenerative disorder with no cure.Astragalus membranaceus is used in Chinese culture as a food supplement to boost immunity.The present study aimed to explore the neuroprotect...Parkinson’s disease(PD)is a common neurodegenerative disorder with no cure.Astragalus membranaceus is used in Chinese culture as a food supplement to boost immunity.The present study aimed to explore the neuroprotective effects of total flavonoids extracted from A.membranaceus(TFA)and their protective mechanisms.TFA offered neuroprotection against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)in the mouse model of Parkinsonism,by improving behavior performance in the gait analysis and pole test,and inhibiting the decline of tyrosine hydroxylase(TH)positive neurons and TH protein expression in substantia nigra of mice.TFA also prevented 1-methyl-4-phenylpyridinium(MPP+)induced neurotoxicity in SHSY5Y cells,by increasing GSH and GSH/GSSG ratio,and reducing reactive oxygen species.In addition,the neuroprotective effects of TFA were associated with its ability to restore MPTP/MPP+induced downregulation of SLC7A11 and glutathione peroxidase 4(GPX-4).In conclusion,we demonstrated that TFA exerted significant neuroprotection against MPTP/MPP+induced neurodegeneration by inhibiting ferroptosis through the regulation of SLC7A11/GPX-4 axis,suggesting the use of TFA as a possible food supplement in the prevention of PD.展开更多
Seafloor polymetallic sulfide resources exhibit significant development potential.In 2011,China received the exploration rights for 10,000 km^2 of a polymetallic sulfides area in the Southwest Indian Ocean;China will ...Seafloor polymetallic sulfide resources exhibit significant development potential.In 2011,China received the exploration rights for 10,000 km^2 of a polymetallic sulfides area in the Southwest Indian Ocean;China will be permitted to retain only 25%of the area in 2021.However,an exploration of seafloor hydrothermal sulfide deposits in China remains in the initial stage.According to the quantitative prediction theory and the exploration status of seafloor sulfides,this paper systematically proposes a quantitative prediction evaluation process of oceanic polymetallic sulfide resources and divides it into three stages:prediction in a large area,prediction in the prospecting region,and the verification and evaluation of targets.The first two stages of the prediction process have been employed in seafloor sulfides prospecting of the Chinese contract area.The results of stage one suggest that the Chinese contract area is located in the high posterior probability area,which indicates good prospecting potential area in the Indian Ocean.In stage two,the Chinese contract area of 48°-52° E has the highest posterior probability value,which can be selected as the reserved region for additional exploration.In stage three,the method of numerical simulation is employed to reproduce the ore-forming process of sulfides to verify the accuracy of the reserved targets obtained from the three-stage prediction.By narrowing the exploration area and gradually improving the exploration accuracy,the prediction will provide a basis for the exploration and exploitation of seafloor polymetallic sulfide resources.展开更多
AIM To retrospectively evaluate the safety and feasibility of a new modified laparoscopic Sugarbaker repair in patients with parastomal hernias.METHODS A retrospective study was performed to analyze eight patients who...AIM To retrospectively evaluate the safety and feasibility of a new modified laparoscopic Sugarbaker repair in patients with parastomal hernias.METHODS A retrospective study was performed to analyze eight patients who underwent parastomal hernia repair between June 2016 and January 2018. All of these patients received modified laparoscopic Sugarbakerhernia repair treatment. This modified technique included an innovative three-point anchoring and complete suturing technique to fix the mesh. All procedures were performed by a skilled hernia surgeon. Demographic data and perioperative outcomes were collected to evaluate the safety and efficacy of this modified technique.RESULTS Of these eight patients, two had concomitant incisional hernias. All the hernias were repaired by the modified laparoscopic Sugarbaker technique with no conversion to laparotomy. Three patients had in-situ reconstruction of intestinal stoma. The median mesh size was300 cm2, and the mean operative time was 205.6 min. The mean postoperative hospitalization time was10.4 d, with a median pain score of 1(visual analog scale method) at postoperative day 1. Two patients developed postoperative complications. One patient had a pocket of effusion surrounding the biologic mesh,and one patient experienced an infection around the reconstructed stoma. Both patients recovered after conservative management. There was no recurrence during the follow-up period(6-22 mo, average 13 mo).CONCLUSION The modified laparoscopic Sugarbaker repair could fix the mesh reliably with mild postoperative pain and a low recurrence rate. The technique is safe and feasible for parastomal hernias.展开更多
In this paper,a minimax design of damped dynamic vibration absorber for a damped primary system is investigated to minimize the vibration magnitude peaks.Moreover,to reduce the sensitivity of the primary system respon...In this paper,a minimax design of damped dynamic vibration absorber for a damped primary system is investigated to minimize the vibration magnitude peaks.Moreover,to reduce the sensitivity of the primary system response to variations of the forcing frequency for a twodegree-of-freedom system,the primary system should have two equal resonance magnitude peaks.To meet this requirement,a set of simplified constraint equations including distribution characteristics of the resonant frequencies of the primary system is established for the minimax objective function.The modified constraint equations have less unknown variables than those by other authors,which not only simplifies the computation but also improves the accuracy of the optimal values.The advantage of the proposed method is illustrated through numerical simulations.展开更多
In the present study,the electrophoretic deposition method was successfully applied as a binder-free and scalable approach to deposit carbonaceous nanomaterials on carbon fiber paper(CFP)for cathode applications in Li...In the present study,the electrophoretic deposition method was successfully applied as a binder-free and scalable approach to deposit carbonaceous nanomaterials on carbon fiber paper(CFP)for cathode applications in Li-S batteries.The microstructural studies of the EPD-CNT film using scanning electron microscopy(SEM)revealed the formation of a crack-free and porous layer of CNTs being uniformly distributed on the CFP surface.The EPD:CFP/CNT/S cathode delivered a capacity around 2.2 times higher than that obtained in the absence of the EPD-CNT film(CFP/S cell)after 50 cycles and a capacity of935 mAh g^-1 after 100 cycles at 0.1 C.The EPD method was then employed to fabricate layer-by-layer structures where the EPD-CNT film was decorated with carbon black particles.The initial capacity as well as the reversible capacity after 100 cycles was further increased by the EPD:CFP/CNT/KB/S layer-by-layer structure to 1473 and 1033 mAh g^-1,respectively,indicating effective suppression of the shuttle effect.In addition,the rate performance of CFP/S was improved by depositing the EPD-CNT and EPD-CNT/carbon black architectures on CFP surface,and even further enhanced through the co-deposition of CNT and Pt nanoparticles by EPD,delivering a specific capacity of around 730 mAh g^-1 at 1 C.Finally,the cathodes fabricated by EPD were observed to outperform those made by the conventional casting method in terms of cycling performance,internal resistance,and polarization.This difference was ascribed to the non-uniform microstructure of the Cast-CNT film,which resulted in poor interfacial connection between the CNT agglomerates,hindering uniform sulfide/sulfur deposition during cycling.The obtained results suggested that the binder-free C/S nanocomposite cathode made by EPD is key to further enhance the specific capacity and energy density of Li-S batteries.展开更多
Concomitant fractures of the hook of hamate and scaphoid are rare injuries to the wrist. Whenever these fractures cannot be effectively managed, nonunion or osteonecrosis is encountered. Subsequent treatment is thus m...Concomitant fractures of the hook of hamate and scaphoid are rare injuries to the wrist. Whenever these fractures cannot be effectively managed, nonunion or osteonecrosis is encountered. Subsequent treatment is thus much more challenging for a hand surgeon or orthopedist. Minimally invasive percutaneous internal fixation is an optimal treatment with the potential to minimize injury and reduce fractures. However, the control of iatrogenic injuries, including possible damage to the adjacent vital tissue, is a challenge that needs to be addressed. Herein,we describe the case of a 26-year-old man who presented with fractures to the scaphoid and hook of hamate in his left wrist. Minimally invasive treatment-with closed reduction and percutaneous fixation of the scaphoid, wrist arthroscopy, and closed reduction and percutaneous fixation of the hook of hamate-was performed at our institution. The Mayo score of the wrist, visual analog scale(VAS) for pain, grip strength, pinch strength, and wrist motion in radial/ulnar and flexion/extension deviation were recorded. Primary healing was achieved in both fractures. At the final follow-up, the Mayo score of the wrist was 100(excellent), the VAS score was 0(no pain),and the grip and pinch strength of his injured hand were 90.9% and 83.3%, respectively, compared with the contralateral hand(grip strength: left, 50 kg;right, 55 kg. Pinch strength: left, 20 kg;right, 24 kg). The radialulnar, flexion-extension, and forearm pronation-supination directions were 30°, 140°, and 90°, respectively.Minimally invasive closed reduction with percutaneous internal fixation is an optimal technique with satisfactory outcomes for simultaneous fractures of the hook of hamate and scaphoid. Provided in this paper are details of the technique and technical suggestions for performing the procedure.展开更多
Interleukin 17(IL-17)is an important cytokine that can induce tissue inflammation and is involved in the pathogenesis of numerous autoimmune diseases.However,the regulation of its signaling transduction has not been w...Interleukin 17(IL-17)is an important cytokine that can induce tissue inflammation and is involved in the pathogenesis of numerous autoimmune diseases.However,the regulation of its signaling transduction has not been well described.In this study,we report that thousand and one kinase 1(TAOK1)functions as a negative regulator of IL-17-mediated signal transduction and inflammation.TAOK1 knockdown promotes IL-17-induced cytokine and chemokine expression and the activation of mitogen-activated protein kinases and nuclear factor-κB.We further demonstrate that TAOK1 interacts with IL-17 receptor A(IL-17RA)independent of its kinase activity,and TAOK1 dose-dependently prevents the formation of the IL-17R-Act1(nuclear factor activator 1,also known as tumor necrosis factor receptor-associated factor 3 interacting protein 2)complex.Consistent with this,TAOK1 deficiency exacerbates colitis in the 2,4,6-trinitrobenzenesulfonic acid-induced experimental model of inflammatory bowel disease,likely by its promotion of the IL-17-mediated signaling pathway.TAOK1 expression is decreased in the colons of ulcerative colitis patients.In conclusion,these findings suggest that TAOK1 is involved in the development of IL-17-related autoimmune disorders.展开更多
Objective: To investigate the distributions of human leukocyte antigen (HLA)-A and-B alleles and HLA-A-B haplotypes in the Yi ethnic minority of the Yunnan Province, situated in southwestern China. Methods: DNA typing...Objective: To investigate the distributions of human leukocyte antigen (HLA)-A and-B alleles and HLA-A-B haplotypes in the Yi ethnic minority of the Yunnan Province, situated in southwestern China. Methods: DNA typing for HLA-A and-B loci was performed using the polymerase chain reaction-sequence-based typing (PCR-SBT) method on 114 randomly selected healthy individuals of the Yi population. The allelic frequencies of HLA-A and-B loci were calculated by direct counting and HLA-A-B haplotypes were estimated using the expectation maximization algorithm. Results: A total of 17 HLA-A and 38 HLA-B alleles were found in the Yi population. The most frequent alleles were A2402 (32.46%), A1101 (26.32%), and A0203 (10.09%) at the HLA-A locus and B4601 (12.28%), B1525 (10.09%), B4001 (8.77%), and B3802 (7.89%) at the HLA-B locus. The predominant HLA-A-B haplotypes were A2402-B1525 (7.86%) and A0203-B3802 (5.64%), followed by A1101-B4001 (4.69%). Phylogenetic analysis indicates that the Yi population in the Honghe, Yunnan Province of China basically belongs to groups of southeastern Asian origin, but shares some characteristics with northeastern Asian groups. Conclusion: The present study may add to the understanding of HLA polymorphism in the Yi ethnic group that was poorly defined previously, and provide useful information for bone marrow transplantation, anthropological research, and forensic sciences as well as for disease-association studies.展开更多
Reusable rocket engines are the core components of reusable launch vehicles, and have thus become a major focus of aerospace engineering research in recent years. In practice, subsystem design is based on the overall ...Reusable rocket engines are the core components of reusable launch vehicles, and have thus become a major focus of aerospace engineering research in recent years. In practice, subsystem design is based on the overall index allocation of an engine;therefore, a multidisciplinary optimization approach is necessary. In this study, design of a reusable methane/liquid oxygen(LOX/CH4)rocket engine with a gas generator cycle was investigated using multidisciplinary optimization. Two parameters were chosen as design variables: pressure and fuel mix ratio of the main combustion chamber. Optimization objectives were specific impulse, structural mass, and life cycle cost of the reusable rocket engine, and constraints were assigned to each discipline according to rocket design requirements. Then, an optimization model was developed, and optimal design parameters were acquired for the LOX/CH4 rocket engine. The proposed method is effective for designing the index allocation of reusable rocket engines and takes into account the multidisciplinary nature of complex systems.展开更多
An algebraic structure A is said to have the endomorphism kernel property if everycongruence on A,other than the universal congruence,is the kernel of an endomorphism on A.In thispaper,we consider the EKP(that is,endo...An algebraic structure A is said to have the endomorphism kernel property if everycongruence on A,other than the universal congruence,is the kernel of an endomorphism on A.In thispaper,we consider the EKP(that is,endomorphism kernel property)for an extended Ockham algebraA.In particular,we describe the structure of the finite symmetric extended de Morgan algebras havingEKP.展开更多
Here we introduce a subclass of the class of Ockham algebras ( L ; f ) for which L satisfies the property that for every x ∈ L , there exists n ≥ 0 such that fn ( x ) and fn+1 ( x ) are complementary. We characteriz...Here we introduce a subclass of the class of Ockham algebras ( L ; f ) for which L satisfies the property that for every x ∈ L , there exists n ≥ 0 such that fn ( x ) and fn+1 ( x ) are complementary. We characterize the structure of the lattice of congruences on such an algebra ( L ; f ). We show that the lattice of compact congruences on L is a dual Stone lattice, and in particular, that the lattice Con L of congruences on L is boolean if and only if L is finite boolean. We also show that L is congruence coherent if and only if it is boolean. Finally, we give a sufficient and necessary condition to have the subdirectly irreducible chains.展开更多
文摘Parkinson’s disease(PD)is a common neurodegenerative disorder with no cure.Astragalus membranaceus is used in Chinese culture as a food supplement to boost immunity.The present study aimed to explore the neuroprotective effects of total flavonoids extracted from A.membranaceus(TFA)and their protective mechanisms.TFA offered neuroprotection against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)in the mouse model of Parkinsonism,by improving behavior performance in the gait analysis and pole test,and inhibiting the decline of tyrosine hydroxylase(TH)positive neurons and TH protein expression in substantia nigra of mice.TFA also prevented 1-methyl-4-phenylpyridinium(MPP+)induced neurotoxicity in SHSY5Y cells,by increasing GSH and GSH/GSSG ratio,and reducing reactive oxygen species.In addition,the neuroprotective effects of TFA were associated with its ability to restore MPTP/MPP+induced downregulation of SLC7A11 and glutathione peroxidase 4(GPX-4).In conclusion,we demonstrated that TFA exerted significant neuroprotection against MPTP/MPP+induced neurodegeneration by inhibiting ferroptosis through the regulation of SLC7A11/GPX-4 axis,suggesting the use of TFA as a possible food supplement in the prevention of PD.
基金supported by the China Ocean Mineral Resources R & D Association "Twelfth Five-Year" Major Program under contract No.DY125-11-R-02
文摘Seafloor polymetallic sulfide resources exhibit significant development potential.In 2011,China received the exploration rights for 10,000 km^2 of a polymetallic sulfides area in the Southwest Indian Ocean;China will be permitted to retain only 25%of the area in 2021.However,an exploration of seafloor hydrothermal sulfide deposits in China remains in the initial stage.According to the quantitative prediction theory and the exploration status of seafloor sulfides,this paper systematically proposes a quantitative prediction evaluation process of oceanic polymetallic sulfide resources and divides it into three stages:prediction in a large area,prediction in the prospecting region,and the verification and evaluation of targets.The first two stages of the prediction process have been employed in seafloor sulfides prospecting of the Chinese contract area.The results of stage one suggest that the Chinese contract area is located in the high posterior probability area,which indicates good prospecting potential area in the Indian Ocean.In stage two,the Chinese contract area of 48°-52° E has the highest posterior probability value,which can be selected as the reserved region for additional exploration.In stage three,the method of numerical simulation is employed to reproduce the ore-forming process of sulfides to verify the accuracy of the reserved targets obtained from the three-stage prediction.By narrowing the exploration area and gradually improving the exploration accuracy,the prediction will provide a basis for the exploration and exploitation of seafloor polymetallic sulfide resources.
文摘AIM To retrospectively evaluate the safety and feasibility of a new modified laparoscopic Sugarbaker repair in patients with parastomal hernias.METHODS A retrospective study was performed to analyze eight patients who underwent parastomal hernia repair between June 2016 and January 2018. All of these patients received modified laparoscopic Sugarbakerhernia repair treatment. This modified technique included an innovative three-point anchoring and complete suturing technique to fix the mesh. All procedures were performed by a skilled hernia surgeon. Demographic data and perioperative outcomes were collected to evaluate the safety and efficacy of this modified technique.RESULTS Of these eight patients, two had concomitant incisional hernias. All the hernias were repaired by the modified laparoscopic Sugarbaker technique with no conversion to laparotomy. Three patients had in-situ reconstruction of intestinal stoma. The median mesh size was300 cm2, and the mean operative time was 205.6 min. The mean postoperative hospitalization time was10.4 d, with a median pain score of 1(visual analog scale method) at postoperative day 1. Two patients developed postoperative complications. One patient had a pocket of effusion surrounding the biologic mesh,and one patient experienced an infection around the reconstructed stoma. Both patients recovered after conservative management. There was no recurrence during the follow-up period(6-22 mo, average 13 mo).CONCLUSION The modified laparoscopic Sugarbaker repair could fix the mesh reliably with mild postoperative pain and a low recurrence rate. The technique is safe and feasible for parastomal hernias.
基金supported by the National Natural Science Foundation of China (11072014 and 11172018)
文摘In this paper,a minimax design of damped dynamic vibration absorber for a damped primary system is investigated to minimize the vibration magnitude peaks.Moreover,to reduce the sensitivity of the primary system response to variations of the forcing frequency for a twodegree-of-freedom system,the primary system should have two equal resonance magnitude peaks.To meet this requirement,a set of simplified constraint equations including distribution characteristics of the resonant frequencies of the primary system is established for the minimax objective function.The modified constraint equations have less unknown variables than those by other authors,which not only simplifies the computation but also improves the accuracy of the optimal values.The advantage of the proposed method is illustrated through numerical simulations.
基金financially supported by the City University of Hong Kong through the SRG projects#7004545�support from the Research G rants Council(RGC)of Hong Kongthe Hong Kong Ph D Fellowship Scheme(HKPFS)。
文摘In the present study,the electrophoretic deposition method was successfully applied as a binder-free and scalable approach to deposit carbonaceous nanomaterials on carbon fiber paper(CFP)for cathode applications in Li-S batteries.The microstructural studies of the EPD-CNT film using scanning electron microscopy(SEM)revealed the formation of a crack-free and porous layer of CNTs being uniformly distributed on the CFP surface.The EPD:CFP/CNT/S cathode delivered a capacity around 2.2 times higher than that obtained in the absence of the EPD-CNT film(CFP/S cell)after 50 cycles and a capacity of935 mAh g^-1 after 100 cycles at 0.1 C.The EPD method was then employed to fabricate layer-by-layer structures where the EPD-CNT film was decorated with carbon black particles.The initial capacity as well as the reversible capacity after 100 cycles was further increased by the EPD:CFP/CNT/KB/S layer-by-layer structure to 1473 and 1033 mAh g^-1,respectively,indicating effective suppression of the shuttle effect.In addition,the rate performance of CFP/S was improved by depositing the EPD-CNT and EPD-CNT/carbon black architectures on CFP surface,and even further enhanced through the co-deposition of CNT and Pt nanoparticles by EPD,delivering a specific capacity of around 730 mAh g^-1 at 1 C.Finally,the cathodes fabricated by EPD were observed to outperform those made by the conventional casting method in terms of cycling performance,internal resistance,and polarization.This difference was ascribed to the non-uniform microstructure of the Cast-CNT film,which resulted in poor interfacial connection between the CNT agglomerates,hindering uniform sulfide/sulfur deposition during cycling.The obtained results suggested that the binder-free C/S nanocomposite cathode made by EPD is key to further enhance the specific capacity and energy density of Li-S batteries.
文摘Concomitant fractures of the hook of hamate and scaphoid are rare injuries to the wrist. Whenever these fractures cannot be effectively managed, nonunion or osteonecrosis is encountered. Subsequent treatment is thus much more challenging for a hand surgeon or orthopedist. Minimally invasive percutaneous internal fixation is an optimal treatment with the potential to minimize injury and reduce fractures. However, the control of iatrogenic injuries, including possible damage to the adjacent vital tissue, is a challenge that needs to be addressed. Herein,we describe the case of a 26-year-old man who presented with fractures to the scaphoid and hook of hamate in his left wrist. Minimally invasive treatment-with closed reduction and percutaneous fixation of the scaphoid, wrist arthroscopy, and closed reduction and percutaneous fixation of the hook of hamate-was performed at our institution. The Mayo score of the wrist, visual analog scale(VAS) for pain, grip strength, pinch strength, and wrist motion in radial/ulnar and flexion/extension deviation were recorded. Primary healing was achieved in both fractures. At the final follow-up, the Mayo score of the wrist was 100(excellent), the VAS score was 0(no pain),and the grip and pinch strength of his injured hand were 90.9% and 83.3%, respectively, compared with the contralateral hand(grip strength: left, 50 kg;right, 55 kg. Pinch strength: left, 20 kg;right, 24 kg). The radialulnar, flexion-extension, and forearm pronation-supination directions were 30°, 140°, and 90°, respectively.Minimally invasive closed reduction with percutaneous internal fixation is an optimal technique with satisfactory outcomes for simultaneous fractures of the hook of hamate and scaphoid. Provided in this paper are details of the technique and technical suggestions for performing the procedure.
基金supported by grants from the National Key Research and Development Program of China(2016YFA0502201)the National Natural Science Foundation of China(81571550,81671613)+2 种基金the Natural Science Foundation of Zhejiang Province(LY18H100001,LY15H100001)the‘Double First-rate’project initiatives,the Shanghai Key Laboratory of Cell Engineering(14DZ2272300)the Shanghai Leading Academic Discipline Project(B905).
文摘Interleukin 17(IL-17)is an important cytokine that can induce tissue inflammation and is involved in the pathogenesis of numerous autoimmune diseases.However,the regulation of its signaling transduction has not been well described.In this study,we report that thousand and one kinase 1(TAOK1)functions as a negative regulator of IL-17-mediated signal transduction and inflammation.TAOK1 knockdown promotes IL-17-induced cytokine and chemokine expression and the activation of mitogen-activated protein kinases and nuclear factor-κB.We further demonstrate that TAOK1 interacts with IL-17 receptor A(IL-17RA)independent of its kinase activity,and TAOK1 dose-dependently prevents the formation of the IL-17R-Act1(nuclear factor activator 1,also known as tumor necrosis factor receptor-associated factor 3 interacting protein 2)complex.Consistent with this,TAOK1 deficiency exacerbates colitis in the 2,4,6-trinitrobenzenesulfonic acid-induced experimental model of inflammatory bowel disease,likely by its promotion of the IL-17-mediated signaling pathway.TAOK1 expression is decreased in the colons of ulcerative colitis patients.In conclusion,these findings suggest that TAOK1 is involved in the development of IL-17-related autoimmune disorders.
基金Project supported by the National Natural Science Foundation of China (Nos. 30700470 and 30871348)the Shaan’xi Provincial Science and Technology Research and Development Project Fund (No. 2008K09-02), China
文摘Objective: To investigate the distributions of human leukocyte antigen (HLA)-A and-B alleles and HLA-A-B haplotypes in the Yi ethnic minority of the Yunnan Province, situated in southwestern China. Methods: DNA typing for HLA-A and-B loci was performed using the polymerase chain reaction-sequence-based typing (PCR-SBT) method on 114 randomly selected healthy individuals of the Yi population. The allelic frequencies of HLA-A and-B loci were calculated by direct counting and HLA-A-B haplotypes were estimated using the expectation maximization algorithm. Results: A total of 17 HLA-A and 38 HLA-B alleles were found in the Yi population. The most frequent alleles were A2402 (32.46%), A1101 (26.32%), and A0203 (10.09%) at the HLA-A locus and B4601 (12.28%), B1525 (10.09%), B4001 (8.77%), and B3802 (7.89%) at the HLA-B locus. The predominant HLA-A-B haplotypes were A2402-B1525 (7.86%) and A0203-B3802 (5.64%), followed by A1101-B4001 (4.69%). Phylogenetic analysis indicates that the Yi population in the Honghe, Yunnan Province of China basically belongs to groups of southeastern Asian origin, but shares some characteristics with northeastern Asian groups. Conclusion: The present study may add to the understanding of HLA polymorphism in the Yi ethnic group that was poorly defined previously, and provide useful information for bone marrow transplantation, anthropological research, and forensic sciences as well as for disease-association studies.
文摘Reusable rocket engines are the core components of reusable launch vehicles, and have thus become a major focus of aerospace engineering research in recent years. In practice, subsystem design is based on the overall index allocation of an engine;therefore, a multidisciplinary optimization approach is necessary. In this study, design of a reusable methane/liquid oxygen(LOX/CH4)rocket engine with a gas generator cycle was investigated using multidisciplinary optimization. Two parameters were chosen as design variables: pressure and fuel mix ratio of the main combustion chamber. Optimization objectives were specific impulse, structural mass, and life cycle cost of the reusable rocket engine, and constraints were assigned to each discipline according to rocket design requirements. Then, an optimization model was developed, and optimal design parameters were acquired for the LOX/CH4 rocket engine. The proposed method is effective for designing the index allocation of reusable rocket engines and takes into account the multidisciplinary nature of complex systems.
文摘An algebraic structure A is said to have the endomorphism kernel property if everycongruence on A,other than the universal congruence,is the kernel of an endomorphism on A.In thispaper,we consider the EKP(that is,endomorphism kernel property)for an extended Ockham algebraA.In particular,we describe the structure of the finite symmetric extended de Morgan algebras havingEKP.
文摘Here we introduce a subclass of the class of Ockham algebras ( L ; f ) for which L satisfies the property that for every x ∈ L , there exists n ≥ 0 such that fn ( x ) and fn+1 ( x ) are complementary. We characterize the structure of the lattice of congruences on such an algebra ( L ; f ). We show that the lattice of compact congruences on L is a dual Stone lattice, and in particular, that the lattice Con L of congruences on L is boolean if and only if L is finite boolean. We also show that L is congruence coherent if and only if it is boolean. Finally, we give a sufficient and necessary condition to have the subdirectly irreducible chains.
