CsgA protein monomers consist of aβ-helix of five repeat units possessing several conservative residues and thus,inherently fibrillate.CsgA protein monomers could self-assemble into hierarchical nanofiber structure c...CsgA protein monomers consist of aβ-helix of five repeat units possessing several conservative residues and thus,inherently fibrillate.CsgA protein monomers could self-assemble into hierarchical nanofiber structure cross multiple scales after expression and secretion by E.Coli cells.Previous researches show that CsgA nanofibers could provide adhesion,stiffness,and mechanical homogeneity for the biofilms,host cells’fibronectin binding for internalization,or protection against phage attack.CsgA nanofibers have obtained various applications in material science and synthetic biology.To illustrate,CsgA nanofibers have characteristics of intrinsic hierarchical structures across multiple scales,robustness in harsh environments and programmable functionality via biological tools.Studying the force spectrum or mechanical properties of the nanofiber can provide fundamental information of self-assembly process and ultra-stability in extreme conditions.Single molecule techniques such as atomic force microscopy,optical tweezers,and magnetic tweezers have been widely applied to study proteins.In these studies,proteins are usually chemically conjugated or genetically constructed to have a tag such as histidine,cysteine or biotin.Genetic engineering requires modification of the plasmids encoding the specific protein,and also involve special protein expression and purification.Such study needs collaboration from multi-disciplinary.It normally studies one protein at a time which gives out clear signal but lacks throughput and efficiency.Here we have established a simple method to measure all kinds of proteins without labels.The carboxyl terminus of a protein is attached to the amine group on a magnetic bead,and the amine terminus of the protein is attached to glutaraldehyde on the glass slide.Then we used magnetic tweezers to manipulate and stretched the bead and protein.Extension versus rotation relation was used to identify a single protein or protein fibril.The fiber under tension is also observed by Scanning Electronic Microcopy which convinces that single CsgA-His fibril is linked to a microbead.The peak of diameter distribution is around 15 nm.The fracture of fibers was observed in real time on SEM.Force-extension curves of single fibers are obtained in real time.The force-extension curves generally agree with the worm like chain model.The persistence lengths from the fitting are from 0.9 to 49.8 nm.The elongation ratio increases gradually with force until reaches a plateau.The maximum elongation ratio of 78 nanofibers were made into an elongation ratio distribution diagram,more than half of CsgA-His nanofibers has an elongation ratio from 0 to 2,some are distributed in 2~10,and a few are distributed in 10~18.The maximum elongation ratio of CsgA-His nanofibers is 17.1,indicating that the fibril’s flexibility is much higher than DNA or silk fiber.For forces less than 20 pN,the extension was reversible.With a 42.1 pN holding force,the extension jumped in steps of from 30 to 365 nm and was irreversible.At the scale tested,the jumps corresponded to the unfolding of multiple beta sheets in the fiber.Work for CsgA-His nanofibers during stretching increase with the normalized strain fractions.The experimental data agree with a theoretical prediction for a single CsgA protein from a SMD calculation.Therefore,our results provide key information for the understandings of CsgA protein nanofiber assembly and biofilm robustness.展开更多
Dear Sir,I am Dr.Daniel Ting,from the Department of Ophthalmology,Singapore National Eye Centre,Singapore.I write to present a case of a surprising significant visual improvement following a prolonged 5-month retained...Dear Sir,I am Dr.Daniel Ting,from the Department of Ophthalmology,Singapore National Eye Centre,Singapore.I write to present a case of a surprising significant visual improvement following a prolonged 5-month retained subfoveal perfluorocarbon liquid.Retained perfluorocarbon liquid（PFCL）has been shown to cause decreased visual acuity,retinal pigment epithelial（RPE）toxicity,retinal degeneration and gravity deformation ,展开更多
With summer in full swing,it’s time to fire up the grill.About 80%of American households own a grill,according to a 2013 study by the Hearth,Patio&Barbecue Association.The survey also found that those folks love ...With summer in full swing,it’s time to fire up the grill.About 80%of American households own a grill,according to a 2013 study by the Hearth,Patio&Barbecue Association.The survey also found that those folks love grilling because cooking outdoors feels satisfactory,and the food'tastes so good.'But if you think grills are exclusively reserved for chicken wings and baby back ribs,you’re wrong.Add some of these foods to your next barbecue’s menu and get ready to become a bona fide grill master.展开更多
(一)A boy tells his friend,“The food was terrible at summer camp this year.My first day there,I threw mine in the lake.I got a big surprise when the fish didn’t throw it back.”一个男孩和他的朋友说:“今年夏令营的食...(一)A boy tells his friend,“The food was terrible at summer camp this year.My first day there,I threw mine in the lake.I got a big surprise when the fish didn’t throw it back.”一个男孩和他的朋友说:“今年夏令营的食物太糟糕了。我在那里的第一天就把我的饭菜扔到了湖里。当时鱼没把它扔回来,我还大吃一惊呢。”展开更多
This paper considers the impact of setup time in production scheduling and proposes energy-aware distributed hybrid flow shop scheduling problem with sequence-dependent setup time(EADHFSP-ST)that simultaneously optimi...This paper considers the impact of setup time in production scheduling and proposes energy-aware distributed hybrid flow shop scheduling problem with sequence-dependent setup time(EADHFSP-ST)that simultaneously optimizes the makespan and the energy consumption.We develop a mixed integer linear programming model to describe this problem and present a two-stage adaptive memetic algorithm(TAMA)with a surprisingly popular mechanism.First,a hybrid initialization strategy is designed based on the two optimization objectives to ensure the convergence and diversity of solutions.Second,multiple population co-evolutionary approaches are proposed for global search to escape from traditional cross-randomization and to balance exploration and exploitation.Third,considering that the memetic algorithm(MA)framework is less efficient due to the randomness in the selection of local search operators,TAMA is proposed to balance the local and global searches.The first stage accumulates more experience for updating the surprisingly popular algorithm(SPA)model to guide the second stage operator selection and ensures population convergence.The second stage gets rid of local optimization and designs an elite archive to ensure population diversity.Fourth,five problem-specific operators are designed,and non-critical path deceleration and right-shift strategies are designed for energy efficiency.Finally,to evaluate the performance of the proposed algorithm,multiple experiments are performed on a benchmark with 45 instances.The experimental results show that the proposed TAMA can solve the problem effectively.展开更多
In recent years,the assessment of proprioceptive function has received increased attention in clinical and motor skill research.This is not surprising given the growing body of scientific evidence on the importance of...In recent years,the assessment of proprioceptive function has received increased attention in clinical and motor skill research.This is not surprising given the growing body of scientific evidence on the importance of proprioceptive information for controlling nearly all facets of human movement;from standing to performing highly skilled movement patterns展开更多
O. Henry is a famous short stores writer who won fame abroad. His stories are known for their wit and twist endings. The thesis analyzes his representative work A Service Of Love from different points view. It is help...O. Henry is a famous short stores writer who won fame abroad. His stories are known for their wit and twist endings. The thesis analyzes his representative work A Service Of Love from different points view. It is helpful to understand O. Henry's work better.展开更多
This essay presents a reflection on the main implications of Complexity Theory for science in general, redefining and dispelling myths of traditional science, and Sociology in particular, suggesting a redefinition of ...This essay presents a reflection on the main implications of Complexity Theory for science in general, redefining and dispelling myths of traditional science, and Sociology in particular, suggesting a redefinition of Parsons’ classic concept of Social System, articulated around the property of self-maintenance of order rather than on its possible discontinuity and instability. It argues that Complexity Theory has established the limits of Classic Science, leading to a more realistic awareness of working and evolution mechanisms of Natural and Social Systems and showing the limits of our capacity to predict and control events. Dissipative structures have shown the creative role of time. Instability, emergence, surprise, unpredictability are the rule rather than the exception when systems move away from equilibrium (entropy), even if these processes are generated from a system’s deterministic working mechanisms. Therefore, we have come to realize how constructive the contribution of Complexity is, in regards to the long lasting problem of the relationship between order and disorder. Today, the terms of this relationship have been re-specified in its new configuration of inter-relationship link, according to a unicum which finds its synthesis in self-organization and deterministic chaos concepts. From this perspective, as Prigogine suggested, studies on Complex Systems are heading toward a historical, biological conception of Physics, and a new alliance between natural systems and living, social systems. Non-linearity, far from equilibrium self-organization, emergence and surprise meet at all levels, as this paper attempts to highlight. In Sociology, insights of Complexity Theory have contributed to a new way of thinking about social systems, by re-addressing some fundamental issues starting to social system, emergence and change concepts. The current social system conception as complex dynamical systems is supported by a profitable use of non-liner models (in particular, the Logistic map) in the study of social processes.展开更多
Empirical study on the factors that induce jumps in interest rates in the euro area is still missing. In this paper, maximum likelihood estimates of I-distribution parameters are extracted using as a first step, an or...Empirical study on the factors that induce jumps in interest rates in the euro area is still missing. In this paper, maximum likelihood estimates of I-distribution parameters are extracted using as a first step, an original linear model. According to the contribution of ([1] [2]) in the case of developing a class of Poisson-Gaussian model, we try to enhance the predictive power of this model by distinguishing between a pure Gaussian and Poisson-Gaussian distributions. Such an empirical tool permits to optimizing results through a comparative analysis dealing with the fluctuation of the Euro-interbank offered rate and its statistical descriptive behaviour. The analytical and empirical methods try to evaluate the behavioural success of the ECB intervention in setting interest rates for different maturities. Jumps in euribor interest rate can mainly be linked to surprise decisions of the European Central Bank, and the too frequent meetings of the ECB before November 2001. Despite this special event that leads to a certain lack of predictability, other few day-of-week effects are modelled to prove eventual evidence of bond market overreaction. Empirical results prove that Mondays and Wednesdays are the preponderant days. Regarding monetary policy, negative surprises induce larger jumps than positive ones.展开更多
As expats in Beijing,t h e r e a r e m a n yaspects of life thatseem surprising,orthat we may have trouble get-ting used to.The most visibleand concrete aspect of life inChina,its traffic,has provedto be a constant hu...As expats in Beijing,t h e r e a r e m a n yaspects of life thatseem surprising,orthat we may have trouble get-ting used to.The most visibleand concrete aspect of life inChina,its traffic,has provedto be a constant hurdle展开更多
The series of Harry Potter and the series of The Hunger Games are the most frequently mentioned children＇s and youngster＇s stories after The Adventures of Tom Sawyer. Both of them are children＇s and youngster＇s fa...The series of Harry Potter and the series of The Hunger Games are the most frequently mentioned children＇s and youngster＇s stories after The Adventures of Tom Sawyer. Both of them are children＇s and youngster＇s favorite stories. All of them are about children＇s adventures. But because of the time and history, they represent different themes of the time. This research paper aims at analyzing the Game Spirits in the first two. The suspense and surprise, fantastic adventures and time interweaving are shown in Harry Potter and the Prisoner of Azkaban. And the unbelievable background, the lucky number, image of gamble, and the game against humanity are the Game Spirits in The Hunger Games. The purpose of this thesis is to help people better understand Harry Potter and The Hunger Games in the aspect of Game Spirit. Harry Potter is the full of fantastic adventure while The Hunger Game is a story full of survival.展开更多
Felix had just drifted off to sleep when the bed shook andsprung a surprise on him.“Ha,ha,” Chadwick laughed.“Thatsure woke you up.”Felix frowned.“You be careful or
There is an old Hindi proverb, it goes, "Language changes every eighteenor twenty miles". Despite the influence of television and radio, you canstill find a surprising number of regional varieties of spoken ...There is an old Hindi proverb, it goes, "Language changes every eighteenor twenty miles". Despite the influence of television and radio, you canstill find a surprising number of regional varieties of spoken English withinthe United States, Canada, Australia and especially within the BritishIsles.展开更多
Would you like to spend your holidays traveling by ballon? The first balloon trip took place in France in 1783. It was lasted for only 8 minutes. About a year years late, an American and a Franchman decided to cross t...Would you like to spend your holidays traveling by ballon? The first balloon trip took place in France in 1783. It was lasted for only 8 minutes. About a year years late, an American and a Franchman decided to cross the Channel by a balloon. High over the Channel, they discovered a hole on the balloon. The hole became bigger and bigger. The gas keeping the balloon up was escaped. The men threw all their belongs into the water make the balloon lighter. It started to rise higher agai, but it was still too close to water.展开更多
基金supported by the National Science Foundation of China ( 11772133, 11372116)
文摘CsgA protein monomers consist of aβ-helix of five repeat units possessing several conservative residues and thus,inherently fibrillate.CsgA protein monomers could self-assemble into hierarchical nanofiber structure cross multiple scales after expression and secretion by E.Coli cells.Previous researches show that CsgA nanofibers could provide adhesion,stiffness,and mechanical homogeneity for the biofilms,host cells’fibronectin binding for internalization,or protection against phage attack.CsgA nanofibers have obtained various applications in material science and synthetic biology.To illustrate,CsgA nanofibers have characteristics of intrinsic hierarchical structures across multiple scales,robustness in harsh environments and programmable functionality via biological tools.Studying the force spectrum or mechanical properties of the nanofiber can provide fundamental information of self-assembly process and ultra-stability in extreme conditions.Single molecule techniques such as atomic force microscopy,optical tweezers,and magnetic tweezers have been widely applied to study proteins.In these studies,proteins are usually chemically conjugated or genetically constructed to have a tag such as histidine,cysteine or biotin.Genetic engineering requires modification of the plasmids encoding the specific protein,and also involve special protein expression and purification.Such study needs collaboration from multi-disciplinary.It normally studies one protein at a time which gives out clear signal but lacks throughput and efficiency.Here we have established a simple method to measure all kinds of proteins without labels.The carboxyl terminus of a protein is attached to the amine group on a magnetic bead,and the amine terminus of the protein is attached to glutaraldehyde on the glass slide.Then we used magnetic tweezers to manipulate and stretched the bead and protein.Extension versus rotation relation was used to identify a single protein or protein fibril.The fiber under tension is also observed by Scanning Electronic Microcopy which convinces that single CsgA-His fibril is linked to a microbead.The peak of diameter distribution is around 15 nm.The fracture of fibers was observed in real time on SEM.Force-extension curves of single fibers are obtained in real time.The force-extension curves generally agree with the worm like chain model.The persistence lengths from the fitting are from 0.9 to 49.8 nm.The elongation ratio increases gradually with force until reaches a plateau.The maximum elongation ratio of 78 nanofibers were made into an elongation ratio distribution diagram,more than half of CsgA-His nanofibers has an elongation ratio from 0 to 2,some are distributed in 2~10,and a few are distributed in 10~18.The maximum elongation ratio of CsgA-His nanofibers is 17.1,indicating that the fibril’s flexibility is much higher than DNA or silk fiber.For forces less than 20 pN,the extension was reversible.With a 42.1 pN holding force,the extension jumped in steps of from 30 to 365 nm and was irreversible.At the scale tested,the jumps corresponded to the unfolding of multiple beta sheets in the fiber.Work for CsgA-His nanofibers during stretching increase with the normalized strain fractions.The experimental data agree with a theoretical prediction for a single CsgA protein from a SMD calculation.Therefore,our results provide key information for the understandings of CsgA protein nanofiber assembly and biofilm robustness.
文摘Dear Sir,I am Dr.Daniel Ting,from the Department of Ophthalmology,Singapore National Eye Centre,Singapore.I write to present a case of a surprising significant visual improvement following a prolonged 5-month retained subfoveal perfluorocarbon liquid.Retained perfluorocarbon liquid（PFCL）has been shown to cause decreased visual acuity,retinal pigment epithelial（RPE）toxicity,retinal degeneration and gravity deformation ,
文摘With summer in full swing,it’s time to fire up the grill.About 80%of American households own a grill,according to a 2013 study by the Hearth,Patio&Barbecue Association.The survey also found that those folks love grilling because cooking outdoors feels satisfactory,and the food'tastes so good.'But if you think grills are exclusively reserved for chicken wings and baby back ribs,you’re wrong.Add some of these foods to your next barbecue’s menu and get ready to become a bona fide grill master.
文摘(一)A boy tells his friend,“The food was terrible at summer camp this year.My first day there,I threw mine in the lake.I got a big surprise when the fish didn’t throw it back.”一个男孩和他的朋友说:“今年夏令营的食物太糟糕了。我在那里的第一天就把我的饭菜扔到了湖里。当时鱼没把它扔回来,我还大吃一惊呢。”
基金supported by the National Natural Science Foundation of China(No.62076225).
文摘This paper considers the impact of setup time in production scheduling and proposes energy-aware distributed hybrid flow shop scheduling problem with sequence-dependent setup time(EADHFSP-ST)that simultaneously optimizes the makespan and the energy consumption.We develop a mixed integer linear programming model to describe this problem and present a two-stage adaptive memetic algorithm(TAMA)with a surprisingly popular mechanism.First,a hybrid initialization strategy is designed based on the two optimization objectives to ensure the convergence and diversity of solutions.Second,multiple population co-evolutionary approaches are proposed for global search to escape from traditional cross-randomization and to balance exploration and exploitation.Third,considering that the memetic algorithm(MA)framework is less efficient due to the randomness in the selection of local search operators,TAMA is proposed to balance the local and global searches.The first stage accumulates more experience for updating the surprisingly popular algorithm(SPA)model to guide the second stage operator selection and ensures population convergence.The second stage gets rid of local optimization and designs an elite archive to ensure population diversity.Fourth,five problem-specific operators are designed,and non-critical path deceleration and right-shift strategies are designed for energy efficiency.Finally,to evaluate the performance of the proposed algorithm,multiple experiments are performed on a benchmark with 45 instances.The experimental results show that the proposed TAMA can solve the problem effectively.
基金supported by the Deutsche Forschungsgemeinschaft (No.KR 4595/1-1)
文摘In recent years,the assessment of proprioceptive function has received increased attention in clinical and motor skill research.This is not surprising given the growing body of scientific evidence on the importance of proprioceptive information for controlling nearly all facets of human movement;from standing to performing highly skilled movement patterns
文摘O. Henry is a famous short stores writer who won fame abroad. His stories are known for their wit and twist endings. The thesis analyzes his representative work A Service Of Love from different points view. It is helpful to understand O. Henry's work better.
文摘This essay presents a reflection on the main implications of Complexity Theory for science in general, redefining and dispelling myths of traditional science, and Sociology in particular, suggesting a redefinition of Parsons’ classic concept of Social System, articulated around the property of self-maintenance of order rather than on its possible discontinuity and instability. It argues that Complexity Theory has established the limits of Classic Science, leading to a more realistic awareness of working and evolution mechanisms of Natural and Social Systems and showing the limits of our capacity to predict and control events. Dissipative structures have shown the creative role of time. Instability, emergence, surprise, unpredictability are the rule rather than the exception when systems move away from equilibrium (entropy), even if these processes are generated from a system’s deterministic working mechanisms. Therefore, we have come to realize how constructive the contribution of Complexity is, in regards to the long lasting problem of the relationship between order and disorder. Today, the terms of this relationship have been re-specified in its new configuration of inter-relationship link, according to a unicum which finds its synthesis in self-organization and deterministic chaos concepts. From this perspective, as Prigogine suggested, studies on Complex Systems are heading toward a historical, biological conception of Physics, and a new alliance between natural systems and living, social systems. Non-linearity, far from equilibrium self-organization, emergence and surprise meet at all levels, as this paper attempts to highlight. In Sociology, insights of Complexity Theory have contributed to a new way of thinking about social systems, by re-addressing some fundamental issues starting to social system, emergence and change concepts. The current social system conception as complex dynamical systems is supported by a profitable use of non-liner models (in particular, the Logistic map) in the study of social processes.
文摘Empirical study on the factors that induce jumps in interest rates in the euro area is still missing. In this paper, maximum likelihood estimates of I-distribution parameters are extracted using as a first step, an original linear model. According to the contribution of ([1] [2]) in the case of developing a class of Poisson-Gaussian model, we try to enhance the predictive power of this model by distinguishing between a pure Gaussian and Poisson-Gaussian distributions. Such an empirical tool permits to optimizing results through a comparative analysis dealing with the fluctuation of the Euro-interbank offered rate and its statistical descriptive behaviour. The analytical and empirical methods try to evaluate the behavioural success of the ECB intervention in setting interest rates for different maturities. Jumps in euribor interest rate can mainly be linked to surprise decisions of the European Central Bank, and the too frequent meetings of the ECB before November 2001. Despite this special event that leads to a certain lack of predictability, other few day-of-week effects are modelled to prove eventual evidence of bond market overreaction. Empirical results prove that Mondays and Wednesdays are the preponderant days. Regarding monetary policy, negative surprises induce larger jumps than positive ones.
文摘As expats in Beijing,t h e r e a r e m a n yaspects of life thatseem surprising,orthat we may have trouble get-ting used to.The most visibleand concrete aspect of life inChina,its traffic,has provedto be a constant hurdle
文摘The series of Harry Potter and the series of The Hunger Games are the most frequently mentioned children＇s and youngster＇s stories after The Adventures of Tom Sawyer. Both of them are children＇s and youngster＇s favorite stories. All of them are about children＇s adventures. But because of the time and history, they represent different themes of the time. This research paper aims at analyzing the Game Spirits in the first two. The suspense and surprise, fantastic adventures and time interweaving are shown in Harry Potter and the Prisoner of Azkaban. And the unbelievable background, the lucky number, image of gamble, and the game against humanity are the Game Spirits in The Hunger Games. The purpose of this thesis is to help people better understand Harry Potter and The Hunger Games in the aspect of Game Spirit. Harry Potter is the full of fantastic adventure while The Hunger Game is a story full of survival.
文摘Felix had just drifted off to sleep when the bed shook andsprung a surprise on him.“Ha,ha,” Chadwick laughed.“Thatsure woke you up.”Felix frowned.“You be careful or
文摘There is an old Hindi proverb, it goes, "Language changes every eighteenor twenty miles". Despite the influence of television and radio, you canstill find a surprising number of regional varieties of spoken English withinthe United States, Canada, Australia and especially within the BritishIsles.
文摘Would you like to spend your holidays traveling by ballon? The first balloon trip took place in France in 1783. It was lasted for only 8 minutes. About a year years late, an American and a Franchman decided to cross the Channel by a balloon. High over the Channel, they discovered a hole on the balloon. The hole became bigger and bigger. The gas keeping the balloon up was escaped. The men threw all their belongs into the water make the balloon lighter. It started to rise higher agai, but it was still too close to water.
