Stoichiometry has long been addressed in the studies of ecosystem ecology, but it was almost ignored for a long time. Until recently, ecologists have become aware that stoichiometry could provide a new tool to study e...Stoichiometry has long been addressed in the studies of ecosystem ecology, but it was almost ignored for a long time. Until recently, ecologists have become aware that stoichiometry could provide a new tool to study ecology from genes to the biosphere. Among this trend, N:P stoichiometry is used actively in ecological interactions since nitrogen (N) and phosphorus (P) are the two most important elements in most ecosystems. This article reviews the application of N:P stoichiometry to the studies of ecological problems at different levels, including ecosystem, community and species. Meanwhile, we also provide the cellular basis of N:P stoichiometry, identify the shortages in the use of N:P stoichiometry theory, and put forward some perspectives for future research to be conducted.展开更多
[Objective]The aim was to carry out stoichiometry on the early-spring herbs functional group in subtropical artificial wetland.[Method]UV-Vis spectrophotometer was used for the determination of nitrate-nitrogen,ammoni...[Objective]The aim was to carry out stoichiometry on the early-spring herbs functional group in subtropical artificial wetland.[Method]UV-Vis spectrophotometer was used for the determination of nitrate-nitrogen,ammonium nitrogen and phosphorus concentrations.Potassium persulfate absorptiometry was used for the measurement of total N content,while the flame photometer was used to detect the potassium and sodium concentration in plants.All the nutrient determination of plant samples were repeated for four times.[Result]The four nutrient concentrations in almost all samples were in the normal range of natural plant nutrition concentrations;in early-spring herbs functional groups,different species showed diversity on the nutrient concentrations;plant height had no significant effect on the nutrient concentrations in plants;the nutrient concentrations of non-grass group plants were higher than that of grass group plants;the nutrient concentrations of the annual herb were higher than that of perennial herbs.[Conclusion]The study had provided basis for the understanding of the effects of changes in nutritional conditions on species diversity,community structure and succession of the system.展开更多
The application of overgrowth microorganisms in ocean research was discussed,using the China National Knowledge Infrastructure(CNKI)network database to retrieve papers on the topic of symbiotic microbes(=198)and symbi...The application of overgrowth microorganisms in ocean research was discussed,using the China National Knowledge Infrastructure(CNKI)network database to retrieve papers on the topic of symbiotic microbes(=198)and symbiotic marine microorganisms(n=94).Bibliometric Analysis are conducted in terms of the published trends,subject headings and other aspects.The output of literature in this field has increased rapidly in the past15years.57.4%of the papers were published in the last five years.And the relevance of research topics has increased in recent years.The current research focuses on community diversity,secondary metabolites,biological activities and antibacterial activities.Literature analysis is helpful to understand the overall development trend of overgrowth microorganisms in ocean research.展开更多
We link nuclear force with gravity. We use statistical entropy to link fine-structure constant （ct） and cosmological constant, showing mystical number 137 （as reciprocal of increasing entropy of the universe） as n...We link nuclear force with gravity. We use statistical entropy to link fine-structure constant （ct） and cosmological constant, showing mystical number 137 （as reciprocal of increasing entropy of the universe） as negative entropy needed for life to exist. If our computational route applies to the physical universe, it should apply to life. Molecular biology is searching for the fundamental source of information that would link to the information in DNA.展开更多
This study aims to investigate the effects of region and three regional dominated mangrove species(Avicennia marina, Aegiceras corniculatum and Kandelia candel) on the distribution of inorganic nitrogen and phosphorus...This study aims to investigate the effects of region and three regional dominated mangrove species(Avicennia marina, Aegiceras corniculatum and Kandelia candel) on the distribution of inorganic nitrogen and phosphorus. Measurement of the inorganic nitrogen and phosphorus and enzymatic activities was carried out in soils covered by three mangrove species in the Quanzhou Bay estuarine wetlands, a typical coastal wetland in China.Species with a higher biomass in upstream and midstream absorb more nitrogen from soils, and the retention of the available phosphorus in the soils of different regions causes the regional variation of phosphorus. In areas dominated by A. marina, nitrate nitrogen is lower while available phosphorus is higher. Meanwhile, nitrate nitrogen and available phosphorus are higher in the soils covered by K. candel.Moreover, all three species affect the elemental and enzymic stoichiometry. The mangrove species influences the diversity of the elemental and enzymic stoichiometric relationship through differential microenvironments, which induce the biodiversity of wetland ecosystems. Thus, this study may facilitate a better understanding of the transformation ability of mangroves to nitrogen and phosphorus and will therefore be beneficial for providing a basis for the ecological restoration of estuarine wetlands.展开更多
Arbuscular mycorrhizal fungi(AMF)enhance plant tolerance to abiotic stresses like salinity and improve crop yield.However,their effects are variable,and the underlying cause of such variation remains largely unknown.T...Arbuscular mycorrhizal fungi(AMF)enhance plant tolerance to abiotic stresses like salinity and improve crop yield.However,their effects are variable,and the underlying cause of such variation remains largely unknown.This study aimed to assess how drought modifed the effect of AMF on plant resistance to high calcium-saline stress.A pot experiment was performed to examine how AMF inoculation affects the growth,photosynthetic activity,nutrient uptake and carbon(C),nitrogen(N)and phosphorus(P)stoichiometric ratio(C:N:P)of maize under high calcium stress and contrasting water conditions.The results showed that high calcium stress signifcantly reduced mycorrhizal colonization,biomass accumulation,C assimilation rate and C:N stoichiometric ratio in plant tissues.Besides,the adverse effects of calcium stress on photosynthesis were exacerbated under drought.AMF inoculation profoundly alleviated such reductions under drought and saline stress.However,it barely affected maize performance when subjected to calcium stress under well-watered conditions.Moreover,watering changed AMF impact on nutrient allocation in plant tissues.Under well-watered conditions,AMF stimulated P accumulation in roots and plant growth,but did not induce leaf P accumulation proportional to C and N,resulting in increased leaf C:P and N:P ratios under high calcium stress.In contrast,AMF decreased N content and the N:P ratio in leaves under drought.Overall,AMF inoculation improved maize resistance to calcium-salt stress through enhanced photosynthesis and modulation of nutrient stoichiometry,particularly under water defcit conditions.These results highlighted the regulatory role of AMF in carbon assimilation and nutrient homeostasis under compound stresses,and provide signifcant guidance on the improvement of crop yield in saline and arid regions.展开更多
Tropical mountain ecosystems are usually colonized by numerous invasive plant species and represent an ideal‘natural laboratory’to study the effects of altitude on plant invasion.The aim of this study was to investi...Tropical mountain ecosystems are usually colonized by numerous invasive plant species and represent an ideal‘natural laboratory’to study the effects of altitude on plant invasion.The aim of this study was to investigate the soil chemical and microbiological properties along an altitudinal gradient on a mountain colonized by the invader Ageratina adenophora.Rhizosphere soil of A.adenophora was collected over an altitudinal gradient(1400–2400 m)in Ailao Shan,China.We determined soil organic carbon(C),nutrient contents,enzyme activities,bacterial community composition as well as C and nitrogen(N)contents of the plant roots.Ecoenzymatic stoichiometric indices were calculated to estimate the relative C,N or P limitations of the microbial community.There was a significant effect of altitude on soil organic C in the rhizosphere,and a turning point in these measured variables was detected at an altitude of 2000 m.At low elevations,the rapid growth of invasive plants depleted the deficient phosphorus(P)in tropical soils,leading to microbial P limitation;at high elevations,microbes invested more energy to obtain C from resistant litter,leading to microbial C limitation.Bacterial beta diversity and soil pH contributed most to the altitudinal differences in ecoenzymatic stoichiometry,and Proteobacteria and Acidobacteria were the dominant bacterial phyla that determined the nutrient uptake status of microorganisms.These results demonstrate how microbial nutrient acquisition belowground of A.adenophora along an altitudinal gradient,which could contribute to further knowledge about the effects of altitude on biological invasion.展开更多
A novel method applying simple, rapid, effective and inexpensive excitation-emission matrix （EEM） fluorescence spectroscopy coupled with second-order calibration method for simultaneous determination of ethoxyquin ...A novel method applying simple, rapid, effective and inexpensive excitation-emission matrix （EEM） fluorescence spectroscopy coupled with second-order calibration method for simultaneous determination of ethoxyquin （EQ） and tert-butylhydroquinone （TBHQ） contents in biological fluid samples was developed. After a simple data preprocessing that was to insert zeros below the first-order Rayleigh scattering, the second-order calibration method based on the alternating normalization-weighed error （ANWE） algorithm was used to deal with EEM data. Via the introduced ＂second-order advantage＂, the individual con- centrations of the analytes of interest could be obtained even in the presence of uncalibrated interferences. The experimental concentration ranges for the analytes were as follows： EQ, from 4.58 to 20.6 p.g mL-1 in plasma and from 6.87 to 20.6 gg mL-1 in urine; TBHQ, from 4.49 to 20.2 ~tg mL-1 in plasma and from 6.73 to 22.4 I.tg mL-l in urine. The recoveries from spiked bi- ological fluid samples were in the ranges of 92.8%-106.2% for EQ and 94.6%-107.2% for TBHQ. These results demonstrate that the three-dimensional EEM fluorescence with second-order calibration method is a powerful tool for obtaining both EQ and TBHQ quantitative results in plasma and urine samples, and could be applied to more complex matrices.展开更多
All organisms need elements in fixed proportions for carrying out normal metabolic processes and how flexible they are depends on how effective they are utilizing these resources from external sources.It is important ...All organisms need elements in fixed proportions for carrying out normal metabolic processes and how flexible they are depends on how effective they are utilizing these resources from external sources.It is important to understand the interactions among plant,soil and microbial biomass carbon(C),nitrogen(N)and phosphorus(P)stoichiometry under different conditions of resource supply.We conducted a pot experiment on 1-year-old Robinia pseudoacacia seedlings for nearly 5 months under different water,nitrogen and phosphorus supplies,and we determined plant,soil and microbial biomass C,N and P stoichiometry.We found that plant,soil and microbial nutrients and stoichiometry exhibited a certain degree of plasticity in response to the changes in water and nutrient conditions in their environments.Variation partitioning analysis showed that root stoichiometry accounted for a large part of the variance in microbial stoichiometry.Structural equation modeling further revealed that root stoichiometry and leaf stoichiometry were two direct factors affecting microbial biomass C:N and C:P,and that root stoichiometry had the greatest direct effect.In addition,the degree of homeostasis for microbial biomass C and C:P was more sensitive to changes in soil nutrients than changes in other factors,and other elements and elemental ratios displayed strict homeostasis.These results highlight the importance of studying microbial stoichiometry in improving our understanding of nutrient cycling of the plant-soil system under different water and nutrient supply.展开更多
Objective： In pedicle screw fixation, the heads of monoaxial screws need to be directed in the same straight line to accommodate the rod placement by backing out during operation, which decreases the insertional torq...Objective： In pedicle screw fixation, the heads of monoaxial screws need to be directed in the same straight line to accommodate the rod placement by backing out during operation, which decreases the insertional torque and internal fixation strength. While polyaxial screws facilitate the assembly of the connecting rod, but its ball-in-cup locking mechanism reduces the static compressive bending yield strength as compared with monoaxial screws. Our study aimed to assess the mechanical performance of a modified pedicle screw. Methods： In this study, the tail of the screw body of the modified pedicle screw was designed to be a cylindershaped structure that well matched the inner wall of the screw head and the screw head only rotated around the cyclinder. Monoaxial screws, modified screws and polyaxial screws were respectively assembled into 3 groups ofvertebrectomy models simulated by ultra high molecular weight polyethylene （UHMWPE） blocks. This model was developed according to a standard for destructive mechanical testing published by the American Society for Testing Materials （ASTM F1717-04）. Each screw design had 6 subgroups, including 3 for static tension, load compression and torsion tests, and the rest for dynamic compression tests. In dynamic tests, the cyclic loads were 25%, 50%, and 75% of the compressive bending ultimate loads respectively. Yield load, yield ultimate load, yield stiffness, torsional stiffness, cycles to failure and modes of failure for the 3 types of screws were recorded. The results of modified screws were compared with those ofmonoaxial and polyaxial screws. Results： In static tests, results of bending stiffness, yield load, yield torque and torsional stiffness indicated no significant differences between the modified and monoaxial screws （P〉0.05）, but both differed significantly from those ofpolyaxial screws （P〈0.05）. In dynamic compression tests, both modified and monoaxial screws showed failures that occurred at the insertion point of screw body into the UHMWPE block, while the polyaxial screw group showed screw body swung up and down the screw head because of loosening of the ball-in-cup mechanism. Conclusions： The modified screw is well-designed and biomechanically improved. And it can provide sufficient stability for segment fixation as monoaxial screws.展开更多
Although high quality multiple sequence alignment is an essential task in bioinforma- tics, it becomes a big dilemma nowadays due to the gigantic explosion in the amount of molecular data. The most consuming time and ...Although high quality multiple sequence alignment is an essential task in bioinforma- tics, it becomes a big dilemma nowadays due to the gigantic explosion in the amount of molecular data. The most consuming time and space phase is the distance matrix computation. This paper addresses this issue by proposing a vectorized parallel method that accomplishes the huge number of similarity comparisons faster in less space. Per- formance tests on real biological datasets using core-iT show superior results in terms of time and space.展开更多
文摘Stoichiometry has long been addressed in the studies of ecosystem ecology, but it was almost ignored for a long time. Until recently, ecologists have become aware that stoichiometry could provide a new tool to study ecology from genes to the biosphere. Among this trend, N:P stoichiometry is used actively in ecological interactions since nitrogen (N) and phosphorus (P) are the two most important elements in most ecosystems. This article reviews the application of N:P stoichiometry to the studies of ecological problems at different levels, including ecosystem, community and species. Meanwhile, we also provide the cellular basis of N:P stoichiometry, identify the shortages in the use of N:P stoichiometry theory, and put forward some perspectives for future research to be conducted.
基金Supported by National Natural Science Foundation of China(30370146)~~
文摘[Objective]The aim was to carry out stoichiometry on the early-spring herbs functional group in subtropical artificial wetland.[Method]UV-Vis spectrophotometer was used for the determination of nitrate-nitrogen,ammonium nitrogen and phosphorus concentrations.Potassium persulfate absorptiometry was used for the measurement of total N content,while the flame photometer was used to detect the potassium and sodium concentration in plants.All the nutrient determination of plant samples were repeated for four times.[Result]The four nutrient concentrations in almost all samples were in the normal range of natural plant nutrition concentrations;in early-spring herbs functional groups,different species showed diversity on the nutrient concentrations;plant height had no significant effect on the nutrient concentrations in plants;the nutrient concentrations of non-grass group plants were higher than that of grass group plants;the nutrient concentrations of the annual herb were higher than that of perennial herbs.[Conclusion]The study had provided basis for the understanding of the effects of changes in nutritional conditions on species diversity,community structure and succession of the system.
文摘The application of overgrowth microorganisms in ocean research was discussed,using the China National Knowledge Infrastructure(CNKI)network database to retrieve papers on the topic of symbiotic microbes(=198)and symbiotic marine microorganisms(n=94).Bibliometric Analysis are conducted in terms of the published trends,subject headings and other aspects.The output of literature in this field has increased rapidly in the past15years.57.4%of the papers were published in the last five years.And the relevance of research topics has increased in recent years.The current research focuses on community diversity,secondary metabolites,biological activities and antibacterial activities.Literature analysis is helpful to understand the overall development trend of overgrowth microorganisms in ocean research.
文摘We link nuclear force with gravity. We use statistical entropy to link fine-structure constant （ct） and cosmological constant, showing mystical number 137 （as reciprocal of increasing entropy of the universe） as negative entropy needed for life to exist. If our computational route applies to the physical universe, it should apply to life. Molecular biology is searching for the fundamental source of information that would link to the information in DNA.
基金financial support for this project provided by National Science and Technology Support Program (2009BADB2B04-03)‘‘Hundred Talents Program’’ of Chinese Academy of Sciences
文摘This study aims to investigate the effects of region and three regional dominated mangrove species(Avicennia marina, Aegiceras corniculatum and Kandelia candel) on the distribution of inorganic nitrogen and phosphorus. Measurement of the inorganic nitrogen and phosphorus and enzymatic activities was carried out in soils covered by three mangrove species in the Quanzhou Bay estuarine wetlands, a typical coastal wetland in China.Species with a higher biomass in upstream and midstream absorb more nitrogen from soils, and the retention of the available phosphorus in the soils of different regions causes the regional variation of phosphorus. In areas dominated by A. marina, nitrate nitrogen is lower while available phosphorus is higher. Meanwhile, nitrate nitrogen and available phosphorus are higher in the soils covered by K. candel.Moreover, all three species affect the elemental and enzymic stoichiometry. The mangrove species influences the diversity of the elemental and enzymic stoichiometric relationship through differential microenvironments, which induce the biodiversity of wetland ecosystems. Thus, this study may facilitate a better understanding of the transformation ability of mangroves to nitrogen and phosphorus and will therefore be beneficial for providing a basis for the ecological restoration of estuarine wetlands.
基金supported by China Postdoctoral Science Foundation(2021M703137)Chongqing Postdoctoral Science Foundation(cstc2021jcyj-bshX0195)+2 种基金Postdoctoral Foundation of Jiangsu Province of China(1501014B)Education Department of Sichuan Province(17ZB0211),the Ecological Security and Protection Key Laboratory of Sichuan Province(07144812)the Scientifc Research Foundation of Chongqing University of Technology(2021ZDZ022).
文摘Arbuscular mycorrhizal fungi(AMF)enhance plant tolerance to abiotic stresses like salinity and improve crop yield.However,their effects are variable,and the underlying cause of such variation remains largely unknown.This study aimed to assess how drought modifed the effect of AMF on plant resistance to high calcium-saline stress.A pot experiment was performed to examine how AMF inoculation affects the growth,photosynthetic activity,nutrient uptake and carbon(C),nitrogen(N)and phosphorus(P)stoichiometric ratio(C:N:P)of maize under high calcium stress and contrasting water conditions.The results showed that high calcium stress signifcantly reduced mycorrhizal colonization,biomass accumulation,C assimilation rate and C:N stoichiometric ratio in plant tissues.Besides,the adverse effects of calcium stress on photosynthesis were exacerbated under drought.AMF inoculation profoundly alleviated such reductions under drought and saline stress.However,it barely affected maize performance when subjected to calcium stress under well-watered conditions.Moreover,watering changed AMF impact on nutrient allocation in plant tissues.Under well-watered conditions,AMF stimulated P accumulation in roots and plant growth,but did not induce leaf P accumulation proportional to C and N,resulting in increased leaf C:P and N:P ratios under high calcium stress.In contrast,AMF decreased N content and the N:P ratio in leaves under drought.Overall,AMF inoculation improved maize resistance to calcium-salt stress through enhanced photosynthesis and modulation of nutrient stoichiometry,particularly under water defcit conditions.These results highlighted the regulatory role of AMF in carbon assimilation and nutrient homeostasis under compound stresses,and provide signifcant guidance on the improvement of crop yield in saline and arid regions.
基金supported by Yunnan Fundamental Research Projects(202101AU070150)the National Natural Science Foundation of China(31870524,32071663,32071661).
文摘Tropical mountain ecosystems are usually colonized by numerous invasive plant species and represent an ideal‘natural laboratory’to study the effects of altitude on plant invasion.The aim of this study was to investigate the soil chemical and microbiological properties along an altitudinal gradient on a mountain colonized by the invader Ageratina adenophora.Rhizosphere soil of A.adenophora was collected over an altitudinal gradient(1400–2400 m)in Ailao Shan,China.We determined soil organic carbon(C),nutrient contents,enzyme activities,bacterial community composition as well as C and nitrogen(N)contents of the plant roots.Ecoenzymatic stoichiometric indices were calculated to estimate the relative C,N or P limitations of the microbial community.There was a significant effect of altitude on soil organic C in the rhizosphere,and a turning point in these measured variables was detected at an altitude of 2000 m.At low elevations,the rapid growth of invasive plants depleted the deficient phosphorus(P)in tropical soils,leading to microbial P limitation;at high elevations,microbes invested more energy to obtain C from resistant litter,leading to microbial C limitation.Bacterial beta diversity and soil pH contributed most to the altitudinal differences in ecoenzymatic stoichiometry,and Proteobacteria and Acidobacteria were the dominant bacterial phyla that determined the nutrient uptake status of microorganisms.These results demonstrate how microbial nutrient acquisition belowground of A.adenophora along an altitudinal gradient,which could contribute to further knowledge about the effects of altitude on biological invasion.
基金the National Natural Science Foundation of China (21175041)the National Basic Research Program(2012CB910602) for financial support
文摘A novel method applying simple, rapid, effective and inexpensive excitation-emission matrix （EEM） fluorescence spectroscopy coupled with second-order calibration method for simultaneous determination of ethoxyquin （EQ） and tert-butylhydroquinone （TBHQ） contents in biological fluid samples was developed. After a simple data preprocessing that was to insert zeros below the first-order Rayleigh scattering, the second-order calibration method based on the alternating normalization-weighed error （ANWE） algorithm was used to deal with EEM data. Via the introduced ＂second-order advantage＂, the individual con- centrations of the analytes of interest could be obtained even in the presence of uncalibrated interferences. The experimental concentration ranges for the analytes were as follows： EQ, from 4.58 to 20.6 p.g mL-1 in plasma and from 6.87 to 20.6 gg mL-1 in urine; TBHQ, from 4.49 to 20.2 ~tg mL-1 in plasma and from 6.73 to 22.4 I.tg mL-l in urine. The recoveries from spiked bi- ological fluid samples were in the ranges of 92.8%-106.2% for EQ and 94.6%-107.2% for TBHQ. These results demonstrate that the three-dimensional EEM fluorescence with second-order calibration method is a powerful tool for obtaining both EQ and TBHQ quantitative results in plasma and urine samples, and could be applied to more complex matrices.
基金the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA23070201)National Key Researchand Development Program of China(2016YFC0501605)the National Natural Science Foundation of China(41771549,42077452)。
文摘All organisms need elements in fixed proportions for carrying out normal metabolic processes and how flexible they are depends on how effective they are utilizing these resources from external sources.It is important to understand the interactions among plant,soil and microbial biomass carbon(C),nitrogen(N)and phosphorus(P)stoichiometry under different conditions of resource supply.We conducted a pot experiment on 1-year-old Robinia pseudoacacia seedlings for nearly 5 months under different water,nitrogen and phosphorus supplies,and we determined plant,soil and microbial biomass C,N and P stoichiometry.We found that plant,soil and microbial nutrients and stoichiometry exhibited a certain degree of plasticity in response to the changes in water and nutrient conditions in their environments.Variation partitioning analysis showed that root stoichiometry accounted for a large part of the variance in microbial stoichiometry.Structural equation modeling further revealed that root stoichiometry and leaf stoichiometry were two direct factors affecting microbial biomass C:N and C:P,and that root stoichiometry had the greatest direct effect.In addition,the degree of homeostasis for microbial biomass C and C:P was more sensitive to changes in soil nutrients than changes in other factors,and other elements and elemental ratios displayed strict homeostasis.These results highlight the importance of studying microbial stoichiometry in improving our understanding of nutrient cycling of the plant-soil system under different water and nutrient supply.
文摘Objective： In pedicle screw fixation, the heads of monoaxial screws need to be directed in the same straight line to accommodate the rod placement by backing out during operation, which decreases the insertional torque and internal fixation strength. While polyaxial screws facilitate the assembly of the connecting rod, but its ball-in-cup locking mechanism reduces the static compressive bending yield strength as compared with monoaxial screws. Our study aimed to assess the mechanical performance of a modified pedicle screw. Methods： In this study, the tail of the screw body of the modified pedicle screw was designed to be a cylindershaped structure that well matched the inner wall of the screw head and the screw head only rotated around the cyclinder. Monoaxial screws, modified screws and polyaxial screws were respectively assembled into 3 groups ofvertebrectomy models simulated by ultra high molecular weight polyethylene （UHMWPE） blocks. This model was developed according to a standard for destructive mechanical testing published by the American Society for Testing Materials （ASTM F1717-04）. Each screw design had 6 subgroups, including 3 for static tension, load compression and torsion tests, and the rest for dynamic compression tests. In dynamic tests, the cyclic loads were 25%, 50%, and 75% of the compressive bending ultimate loads respectively. Yield load, yield ultimate load, yield stiffness, torsional stiffness, cycles to failure and modes of failure for the 3 types of screws were recorded. The results of modified screws were compared with those ofmonoaxial and polyaxial screws. Results： In static tests, results of bending stiffness, yield load, yield torque and torsional stiffness indicated no significant differences between the modified and monoaxial screws （P〉0.05）, but both differed significantly from those ofpolyaxial screws （P〈0.05）. In dynamic compression tests, both modified and monoaxial screws showed failures that occurred at the insertion point of screw body into the UHMWPE block, while the polyaxial screw group showed screw body swung up and down the screw head because of loosening of the ball-in-cup mechanism. Conclusions： The modified screw is well-designed and biomechanically improved. And it can provide sufficient stability for segment fixation as monoaxial screws.
文摘Although high quality multiple sequence alignment is an essential task in bioinforma- tics, it becomes a big dilemma nowadays due to the gigantic explosion in the amount of molecular data. The most consuming time and space phase is the distance matrix computation. This paper addresses this issue by proposing a vectorized parallel method that accomplishes the huge number of similarity comparisons faster in less space. Per- formance tests on real biological datasets using core-iT show superior results in terms of time and space.
