The radula is a crucial adaptation for food-processing in molluscs.A deeper understanding of the interaction between the radula and the preferred food is lacking,complicating the inference of the precise ecological ro...The radula is a crucial adaptation for food-processing in molluscs.A deeper understanding of the interaction between the radula and the preferred food is lacking,complicating the inference of the precise ecological roles of radular structures.This study presents the first experimental set-up that allows to study the influence of the radular morphology,specifically the degree of tooth-tooth interlocking(so-called collective effect),on the feeding efficiency.For this purpose,physical 3D models of the teeth were designed using CAD software and 3D printing technique.The feeding efficiencies with models of different degree of interlocking were determined by tensile tests,pulling the models trough agar gels with different viscosities.The forces generated by the models and the masses of the removed gel fragments were determined.We found,that radular models with a high degree of tooth–tooth interlocking performed best as they were able to remove most agar.We additionally broke the teeth and determined,that the teeth with the highest degree of interlocking could resist to highest force.Overall,the study highlights the complex interplay between radular morphology and its ecological function,suggesting that even minor morphological alterations can significantly impact the efficiency and effectiveness of food gathering.Understanding these interactions cannot only shed light on the ecological adaptations of molluscs,but provide further insights into development of more effective grinding,scraping,and cleaning technical devices.展开更多
Ⅰ. INTRODUCTION The de carbon arc source is one of the fundamental sources used in analytical emission spectroscopy. Though during the past two decades many other new sources have been developed, the carbon arc sourc...Ⅰ. INTRODUCTION The de carbon arc source is one of the fundamental sources used in analytical emission spectroscopy. Though during the past two decades many other new sources have been developed, the carbon arc source, due to its simplicity, suitabitity and sensitivity, is still being commonly used in numerous fields. By using this source in the analysis展开更多
Influenced by rapid changes in climate and landscape features since the Miocene,widely distributed species provide suitable models to study the environmental impact on their evolution and current genetic diversity.The...Influenced by rapid changes in climate and landscape features since the Miocene,widely distributed species provide suitable models to study the environmental impact on their evolution and current genetic diversity.The dice snake Natrix tessellata,widely distributed in the Western Palearctic is one such species.We aimed to resolve a detailed phylogeography of N.tessellata with a focus on the Central Asian clade with 4 and the Anatolia clade with 3 mitochondrial lineages,trace their origin,and correlate the environmental changes that affected their distribution through time.The expected time of divergence of both clades began at 3.7 Mya in the Pliocene,reaching lineage differentiation approximately 1 million years later.The genetic diversity in both clades is rich,suggesting different ancestral areas,glacial refugia,demographic changes,and colonization routes.The Caspian lineage is the most widespread lineage in Central Asia,distributed around the Caspian Sea and reaching the foothills of the Hindu Kush Mountains in Afghanistan,and Eastern European lowlands in the west.Its distribution is limited by deserts,moun-tains,and cold steppe environments.Similarly,Kazakhstan and Uzbekistan lineages followed the Amu Darya and the Syr Darya water systems in Central Asia,with ranges delimited by the large Kyzylkum and Karakum deserts.On the western side,there are several lineages within the Anatolia clade that converged in the central part of the peninsula with 2 being endemic to Western Asia.The distribution of both main clades was affected by expansion from their Pleistocene glacial refugia around the Caspian Sea and in the valleys of Central Asia as well as by environmental changes,mostly through aridification.展开更多
Among plants,there is considerable variation in lifespan:annuals live less than one year,whereas perennials live for several years,with the longest-living perennial having survived 43,600 years.As proposed by the Disp...Among plants,there is considerable variation in lifespan:annuals live less than one year,whereas perennials live for several years,with the longest-living perennial having survived 43,600 years.As proposed by the Disposable Soma Theory,this lifespan variation among plants likely reflects differential investment of limited energy and nutrient resources,with perennials investing more energy and nutrients into biomolecular maintenance compared to annuals in order to ensure persistence over multiple seasons.Such differential investment may be particularly important during periods of exogenous stress,which are known to accelerate biomolecular damage.The present study evaluated this hypothesis using annual and perennial flax(Linum L.)subjected to two exogenous stressors—increased oxidative stress(i.e.,foliar H2O2spraying)and complete prolonged darkness.As chlorophyll has been shown to exhibit degradation in response to changes in environmental conditions,we utilized changes in chlorophyll levels during and after periods of exogenous stress to evaluate our hypotheses.We predicted that i)perennials would exhibit a slower rate of chlorophyll degradation during exposure to exogenous stressors compared to annuals,and ii)perennials would exhibit a faster rate of chlorophyll resynthesis following such exposure compared to annuals.Chlorophyll levels before,during,and after exposure to both exogenous stressors were measured in two separate trails,once using image colour analysis and once using spectrophotometry.While chlorophyll degradation rates in response to oxidative stress did not differ between annuals and perennials,contrary to our predictions,chlorophyll resynthesis rates following such exposure were significantly higher in perennials,as predicted.When plants were subjected to complete prolonged darkness,chlorophyll degradation rates were significantly lower in perennials than annuals,as predicted;however,when plants were subsequently reintroduced to natural photoperiod,chlorophyll resynthesis rates did not consistently differ between annuals and perennials,though they tended to be higher in the latter,as predicted.Overall,our study illuminates that evolutionary transitions between life history strategies in plants have been accompanied by physiological modifications to chlorophyll dynamics that permit perennial species to better maintain chlorophyll levels—and thus photosynthetic energy acquisition-in the face of exogenous stressors,which likely underlies their capacity to survive for multiple growing seasons.Future studies should explore whether other key biomolecules(e.g.,proteins,DNA)are also better maintained in perennial plants,especially in the face of exogenous stress.展开更多
By analyzing the correlation between modal calculations and modal experiments of a typical supporter, an effective finite element analysis( FEA)model of the actual aerospace supporter is created. According to the anal...By analyzing the correlation between modal calculations and modal experiments of a typical supporter, an effective finite element analysis( FEA)model of the actual aerospace supporter is created. According to the analysis of constrained viscoelastic damping, the strategies of PVC have been worked out, and the correlation between modal calculations and modal experiments of the supporter has also been computed, and then, an experiment has been designed based on the calculation results. The results of experiments verify that the PVC strategy can effectively suppress vibration.展开更多
Although widely used, both the Markowitz model and VAR (Value at Risk) model have some limitations in evaluating the risk and return of stock investment. By the analysis of the conceptions of risk and return, together...Although widely used, both the Markowitz model and VAR (Value at Risk) model have some limitations in evaluating the risk and return of stock investment. By the analysis of the conceptions of risk and return, together with the three hypotheses of technological analysis, a novelty model of metering and evaluating the risk and return of stock investment is established. The major indicator of this model , risk-return ratio K, combines the characteristic indicators of risk and return. Regardless of the form of the risk-return probability density functions, this indicator K can always reflect the risk-return performances of the invested stocks clearly and accurately. How to use the model to make optimum investment and how to make portfolio combined with clustering analysis is also explained.展开更多
The electronic structure and the optical properties of Ca<sub>2</sub>Ge have been calculated by the first-principles pseudo potential method. The results of the electric structure show that Ca<sub>2&...The electronic structure and the optical properties of Ca<sub>2</sub>Ge have been calculated by the first-principles pseudo potential method. The results of the electric structure show that Ca<sub>2</sub>Ge bulk is a direct semiconductor with the band gap of 0.306 eV, the conduction band is mainly composed of Ca 3d, the valence bands is mainly composed of Ge 3p. With Sr-doping, Ca<sub>2</sub>Ge bulk is a direct semiconductor with the band gap of 0.350 eV, the conduction bands are mainly composed of Ca 3d and Sr 3d, the valence bands are mainly composed of Ge 3p and Sr 3d. The results of the optical properties show that the dielectric constant of Ca<sub>2</sub>Ge bulk is reduced from 21.52 to 13.94, the reflectivity is decreased, and the absorption is increased with Sr-doping. The optical properties are improved with Sr-doping, the results offer theoretical guide for the optical properties control of Ca<sub>2</sub>Ge.展开更多
The histopathological features of the globoid dysplasia of the human gastric epithelium were described in detail and in series by means of observation of serial sections of 61 cases with globoid dys-plasias. Three gra...The histopathological features of the globoid dysplasia of the human gastric epithelium were described in detail and in series by means of observation of serial sections of 61 cases with globoid dys-plasias. Three grades were divided according to the architectural and cellular atypia of the globoid dys-plasias. The penetration of outer layer globoid dys-plastic cells through the basement membrane of 'the structure of double layers' appeared in typical globoid dysplasia grade II and the infiltration of the globoid dysplastic cells into stroma as well as the formation of incipient focus of signet ring cell carcinoma were described. The twinkling scene of the infiltration of the globoid dysplastic cells into lamina propria through the basement membrane, and the destroying of the basement membrane by the globoid dysplastic cells were shown by means of Gordon Sweet's staining. Through the analysis as for the distribution characteristics of ages and sexes in 61 globoid dysplasia cases and 51 signet ring cell carcinomas, a fact was discovered that the mobility of female cases was ten years prior to that of male ones in average. A conclusion could be made that the globoid dysplasia might be an important precan-cerous lesion of the signet ring cell carcinoma of the stomach.展开更多
The closely related Black-headed Bunting(Emberiza melanocephala,a western Palearctic lineage)and Red-headed Bunting(Emberiza bruniceps,an eastern Palearctic lineage)hybridize and replace each other south of the Caspia...The closely related Black-headed Bunting(Emberiza melanocephala,a western Palearctic lineage)and Red-headed Bunting(Emberiza bruniceps,an eastern Palearctic lineage)hybridize and replace each other south of the Caspian Sea.The parental species have distinct phenotypes and therefore morphology is useful for assessing hybridization in the contact zone.In the years of 1940 and 1977,quite a few hybrids were collected and studied morphologically.Since then,the hybrid zone appears to have expanded westwards,but there has been a time gap in the collection of morphological data.Here we reanalyze bunting specimens morphologically and compare the historical data with recent data.Morphometric and phenotypic traits from three time periods(1940,1977 and recent)were studied to assess phenotypic variation of hybrids,pattern of hybridization,and transgressive traits in the hybrid zone.Our results show that most of the birds in the hybrid zone exhibit intermediate phenotypes(both colors and morphometric characters),ranging from the pure phenotype of either of the parental species.However,hybridization has also produced novel phenotypes not seen in any of the parents.Using a canonical discriminant function analysis,the morphometric characters separated each parental species and the hybrids quite well.Our results showed morphometric intermediacy of hybrids in accordance with phenotypes.We observe a time trend in which recent hybrids are more similar to Red-headed Buntings phenotypically compared to historical samples.This pattern is likely a signature of a westward expansion of the Red-headed Bunting into the breeding range of the Black-headed Bunting.展开更多
Vehicle delay is an important measure to evaluate the signal timings of signalized intersections.When optimization the signal control parameters, delays of vehicles from all approach directions of an intersection shou...Vehicle delay is an important measure to evaluate the signal timings of signalized intersections.When optimization the signal control parameters, delays of vehicles from all approach directions of an intersection should be considered. Based on the analysis of the vehicle delay on an approach of intersection, directed against the typical condition of a congested intersection-over-saturated condition, the paper has analyzed and inferred the intersection delay dynamic formulation, and has established the relation between intersection delay,the signal timings, vehicle arrival rate and the queue lengths, and that provides useful information for understanding vehicle delay of signalized intersection and for establishing performance index function of signal timing optimization.展开更多
An Inverse perturbation method is described for solving the general inverse eigenvalue problem. By taking the analysis of the rotor system as example based upon FEM, the new inverse perturbation method for structural ...An Inverse perturbation method is described for solving the general inverse eigenvalue problem. By taking the analysis of the rotor system as example based upon FEM, the new inverse perturbation method for structural design with specified low-order natural frequencies or frequency constraint bands is detailed as well as its complete theoretical basis. Moreover, formulations to calculate the inverse perturbation parameter ε and method to select the corresponding ε's value properly are also proposed. The proposed method is characterized in reducing frequency analysis and suitable for large and small structrual changes alike. Finally, several different numerical examples for inverse cigenvalue problem are discussed to illustrate the method, which show that this inverse perturbation method Is general and can be applied to other type of structure or dement.展开更多
The aim is to put forward the optimal selecting of weights in variational problemin which the linear advection equation is used as constraint. The selection of the functionalweight coefficients ( FWC) is one of the ke...The aim is to put forward the optimal selecting of weights in variational problemin which the linear advection equation is used as constraint. The selection of the functionalweight coefficients ( FWC) is one of the key problems for the relevant research. It wasarbitrary and subjective to some extent presently. To overcome this difficulty, thereasonable assumptions were given for the observation field and analyzed field, variationalproblems with " weak constraints" and " strong constraints" were considered separately. Bysolving Euler' s equation with the matrix theory and the finite difference method of partialdifferential equation, the objective weight coefficients were obtained in the minimumvariance of the difference between the analyzed field and ideal field. Deduction results showthat theoretically the optimal selection indeed exists in the weighting factors of the costfunction in the means of the minimal variance between the analysis and ideal field in terms ofthe matrix theory and partial differential ( corresponding difference ) equation, if thereasonable assumption from the actual problem is valid and the differnece equation is stable.It may realize the coordination among the weight factors, numerical models and theobservational data. With its theoretical basis as well as its prospects of applications, thisobjective selecting method is probably a way towards the finding of the optimal weightingfactors in the variational problem.展开更多
The dynamic tracking of antibody‒drug conjugates (ADCs) in serum is crucial. However, a versatile bioanalytical platform is lacking due to serious matrix interferences, the heterogeneity and complex biotransformation ...The dynamic tracking of antibody‒drug conjugates (ADCs) in serum is crucial. However, a versatile bioanalytical platform is lacking due to serious matrix interferences, the heterogeneity and complex biotransformation of ADCs, and the recognition deficiencies of traditional affinity technologies. To overcome this, a multiepitope recognition technology (MERT) was developed by simultaneously immobilizing CDR and non-CDR ligands onto MOF@AuNPs. MERT's excellent specificity, ultrahigh ligand density, and potential synergistic recognition ability enable it to target the different key regions of ADCs to overcome the deficiencies of traditional technologies. The binding capacity of MERT for antibodies is ten to hundred times higher than that of the mono-epitope or Fc-specific affinity technologies. Since MERT can efficiently capture target ADCs from serum, a novel bioanalytical platform based on MERT and RPLC‒QTOF-MS has been developed to monitor the dynamic changes of ADCs in serum, including the fast changes of drug-to-antibody ratio from 3.67 to 0.22, the loss of payloads (maytansinol), and the unexpected hydrolysis of the succinimide ring of the linker, which will contribute to clarify the fate of ADCs and provide a theoretical basis for future design. In summary, the MERT-based versatile platform will open a new avenue for in-depth studies of ADCs in biological fluids.展开更多
The detailed kinematic structure of a heavy rain event that occurred in the middle reaches of the Yangtze River was investigated using dual-Doppler radar observation. A variational analysis method was developed to obt...The detailed kinematic structure of a heavy rain event that occurred in the middle reaches of the Yangtze River was investigated using dual-Doppler radar observation. A variational analysis method was developed to obtain the three-dimensional wind fields. Before the analysis, a data preprocessing procedure was carried out, in which the temporal variation with the scanning time interval and the effect of the earth curvature on the data position were taken into account. The analysis shows that a shear line in the lower and middle levels played an important role in the rainfall event. The precipitation fell mainly on the south end of the shear line where southerly flow prevailed and convergence and updraft were obvious. With the movement and decay of the shear line, the precipitation moved and decayed correspondingly.展开更多
Tea is a widely consumed beverage and has many important physiological properties and potential health benefits. In this study, a novel method based on supercritical fluid chromatography coupled with mass spectrometry...Tea is a widely consumed beverage and has many important physiological properties and potential health benefits. In this study, a novel method based on supercritical fluid chromatography coupled with mass spectrometry (SFC-MS) was developed to simultaneously determine 11 amino acids in different types of tea (green teas, Oolong tea, black tea and Pu-erh tea). The separation conditions for the analysis of the selected amino acids including the column type, temperature and backpressure as well as the type of additive, were carefully optimized. The best separation of the 11 amino acids was obtained by adding water (5%, v/v) and trifluoroacetic acid (0.4%, v/v) to the organic modifier (methanol). Finally, the developed SFC-MS method was fully validated and successfully applied to the determination of these amino acids in six different tea samples. Good linearity (r ≥ 0.993), precision (RSDs≤ 2.99%), accuracy (91.95%-107.09%) as well as good sample stability were observed. The limits of detection ranged from 1.42 to 14.69 ng/mL, while the limits of quantification were between 4.53 and 47.0 ng/mL. The results indicate that the contents of the 11 amino acids in the six different tea samples are greatly influenced by the degree of fermentation. The proposed SFC-MS method shows a great potential for further investigation of tea varieties.展开更多
The purpose of this study was to investigate the effects of Zr interlayer on the structure and mechanical properties of TiAlN films, which were deposited on the M2 high-speed steel substrates by means of plasma-enhanc...The purpose of this study was to investigate the effects of Zr interlayer on the structure and mechanical properties of TiAlN films, which were deposited on the M2 high-speed steel substrates by means of plasma-enhanced magnetron sputtering. The result shows that the crystal orientation of Zr/TiAlN films is similar to that of single-layered TiAlN films, but the difference is that AlN(111) of Zr/TiAlN films disappears completely. With respect to Zr interlayer, the texture coefficient of Zr/TiAlN films is approximately 1. Zr/TiAlN films exhibit a compact isometric structure, which is distinctly different from the columnar structure existing in the single-layered TiAlN films and Ti/TiAlN films. The hardness and H3/E*2 of Zr/TiAlN films are, respectively, enhanced to be 36.6 GPa and 0.147. With a few cracks emerging around the indention, the adhesion strength of TiAlN films is obviously advanced by adding Zr metal interlayer.展开更多
One of the most important tools used to evaluate kidney function in the context of chronic kidney disease or other renal function related pathologies is the exploration of glomerular filtration rate (GFR). Iohexol is ...One of the most important tools used to evaluate kidney function in the context of chronic kidney disease or other renal function related pathologies is the exploration of glomerular filtration rate (GFR). Iohexol is up to this moment a good candidate molecule for the GFR assessment since it exhibits minimum protein binding rates and minimum extra-renal clearance, being neither secreted nor reabsorbed at the tubular level. This study proposes and evaluates a new LC-MS/MS method for the iohexol determination from capillary blood, prelevated using volumetric absorbative microsampling (VAMS) systems. As an alternative to VAMS, a brand new HemaPEN■ device for micro-prelevation was also tested. A new high throughput sample preparation protocol adapted for iohexol quantification from whole blood VAMS samples was developed. The medium term stability study of iohexol in dried whole blood VAMS samples that was conducted showed a good stability of this molecule for up to 12 days. By collecting only 10 mL of blood, iohexol can be analyzed from dried whole blood VAMS samples for concentration ranges between 1 and 250 mg/mL. Due to the analyte stability in VAMS for up to 12 days, this approach might be successfully applied for GFR assessment for clinical cases allowing minimum invasiveness and even delayed analysis.展开更多
The technology of Intelligent cure operation is set forth according to developing tendency of smart material and structure. Intelligent-system-based tool was developed in order to operate the autoclave cure of a fiber...The technology of Intelligent cure operation is set forth according to developing tendency of smart material and structure. Intelligent-system-based tool was developed in order to operate the autoclave cure of a fiber reinforced thermosetting matrix composite laminate in an optimal manner. The objective function is comforts for minimizing the total cure time, uniforming the temperature distribution, controling exothermal and minimizing the process-induced residual stresses in the laminate. Data is analyzed on-line to determine the trends in real-time. The results from application of this overall strategy for the curing of composites are presented.展开更多
基金Open Access funding enabled and organized by Projekt DEALfinanced by the Deutsche Forschungsgemeinschaft(DFG)grant 470833544 to WK.
文摘The radula is a crucial adaptation for food-processing in molluscs.A deeper understanding of the interaction between the radula and the preferred food is lacking,complicating the inference of the precise ecological roles of radular structures.This study presents the first experimental set-up that allows to study the influence of the radular morphology,specifically the degree of tooth-tooth interlocking(so-called collective effect),on the feeding efficiency.For this purpose,physical 3D models of the teeth were designed using CAD software and 3D printing technique.The feeding efficiencies with models of different degree of interlocking were determined by tensile tests,pulling the models trough agar gels with different viscosities.The forces generated by the models and the masses of the removed gel fragments were determined.We found,that radular models with a high degree of tooth–tooth interlocking performed best as they were able to remove most agar.We additionally broke the teeth and determined,that the teeth with the highest degree of interlocking could resist to highest force.Overall,the study highlights the complex interplay between radular morphology and its ecological function,suggesting that even minor morphological alterations can significantly impact the efficiency and effectiveness of food gathering.Understanding these interactions cannot only shed light on the ecological adaptations of molluscs,but provide further insights into development of more effective grinding,scraping,and cleaning technical devices.
文摘Ⅰ. INTRODUCTION The de carbon arc source is one of the fundamental sources used in analytical emission spectroscopy. Though during the past two decades many other new sources have been developed, the carbon arc source, due to its simplicity, suitabitity and sensitivity, is still being commonly used in numerous fields. By using this source in the analysis
基金supported by the Slovak Research and Development Agency under the contract APVV-19-0076 and by the grant VEGA 1/0242/21 of the Scientific Grant Agency of the Slovak RepublicSH was supported by the German Research Foundation(DFG,grant no.HO 3792/8-1)The work of OK was carried out within the framework of research topics of the state assignments nos.121032300023-7 and 122031100282-2.The research of DJ in Afghanistan has been approved by the National Environmental Protection Agency of the Islamic Emirate of Afghanistan(permits for access to genetic resources nos.12429 and 12455).
文摘Influenced by rapid changes in climate and landscape features since the Miocene,widely distributed species provide suitable models to study the environmental impact on their evolution and current genetic diversity.The dice snake Natrix tessellata,widely distributed in the Western Palearctic is one such species.We aimed to resolve a detailed phylogeography of N.tessellata with a focus on the Central Asian clade with 4 and the Anatolia clade with 3 mitochondrial lineages,trace their origin,and correlate the environmental changes that affected their distribution through time.The expected time of divergence of both clades began at 3.7 Mya in the Pliocene,reaching lineage differentiation approximately 1 million years later.The genetic diversity in both clades is rich,suggesting different ancestral areas,glacial refugia,demographic changes,and colonization routes.The Caspian lineage is the most widespread lineage in Central Asia,distributed around the Caspian Sea and reaching the foothills of the Hindu Kush Mountains in Afghanistan,and Eastern European lowlands in the west.Its distribution is limited by deserts,moun-tains,and cold steppe environments.Similarly,Kazakhstan and Uzbekistan lineages followed the Amu Darya and the Syr Darya water systems in Central Asia,with ranges delimited by the large Kyzylkum and Karakum deserts.On the western side,there are several lineages within the Anatolia clade that converged in the central part of the peninsula with 2 being endemic to Western Asia.The distribution of both main clades was affected by expansion from their Pleistocene glacial refugia around the Caspian Sea and in the valleys of Central Asia as well as by environmental changes,mostly through aridification.
基金GAM is supported by a Natural Sciences and Engineering Research Council of Canada(NSERC)Discovery Grant。
文摘Among plants,there is considerable variation in lifespan:annuals live less than one year,whereas perennials live for several years,with the longest-living perennial having survived 43,600 years.As proposed by the Disposable Soma Theory,this lifespan variation among plants likely reflects differential investment of limited energy and nutrient resources,with perennials investing more energy and nutrients into biomolecular maintenance compared to annuals in order to ensure persistence over multiple seasons.Such differential investment may be particularly important during periods of exogenous stress,which are known to accelerate biomolecular damage.The present study evaluated this hypothesis using annual and perennial flax(Linum L.)subjected to two exogenous stressors—increased oxidative stress(i.e.,foliar H2O2spraying)and complete prolonged darkness.As chlorophyll has been shown to exhibit degradation in response to changes in environmental conditions,we utilized changes in chlorophyll levels during and after periods of exogenous stress to evaluate our hypotheses.We predicted that i)perennials would exhibit a slower rate of chlorophyll degradation during exposure to exogenous stressors compared to annuals,and ii)perennials would exhibit a faster rate of chlorophyll resynthesis following such exposure compared to annuals.Chlorophyll levels before,during,and after exposure to both exogenous stressors were measured in two separate trails,once using image colour analysis and once using spectrophotometry.While chlorophyll degradation rates in response to oxidative stress did not differ between annuals and perennials,contrary to our predictions,chlorophyll resynthesis rates following such exposure were significantly higher in perennials,as predicted.When plants were subjected to complete prolonged darkness,chlorophyll degradation rates were significantly lower in perennials than annuals,as predicted;however,when plants were subsequently reintroduced to natural photoperiod,chlorophyll resynthesis rates did not consistently differ between annuals and perennials,though they tended to be higher in the latter,as predicted.Overall,our study illuminates that evolutionary transitions between life history strategies in plants have been accompanied by physiological modifications to chlorophyll dynamics that permit perennial species to better maintain chlorophyll levels—and thus photosynthetic energy acquisition-in the face of exogenous stressors,which likely underlies their capacity to survive for multiple growing seasons.Future studies should explore whether other key biomolecules(e.g.,proteins,DNA)are also better maintained in perennial plants,especially in the face of exogenous stress.
基金Sponsored by the National 863 Project of China (Grant No. 863 -2 -416)
文摘By analyzing the correlation between modal calculations and modal experiments of a typical supporter, an effective finite element analysis( FEA)model of the actual aerospace supporter is created. According to the analysis of constrained viscoelastic damping, the strategies of PVC have been worked out, and the correlation between modal calculations and modal experiments of the supporter has also been computed, and then, an experiment has been designed based on the calculation results. The results of experiments verify that the PVC strategy can effectively suppress vibration.
文摘Although widely used, both the Markowitz model and VAR (Value at Risk) model have some limitations in evaluating the risk and return of stock investment. By the analysis of the conceptions of risk and return, together with the three hypotheses of technological analysis, a novelty model of metering and evaluating the risk and return of stock investment is established. The major indicator of this model , risk-return ratio K, combines the characteristic indicators of risk and return. Regardless of the form of the risk-return probability density functions, this indicator K can always reflect the risk-return performances of the invested stocks clearly and accurately. How to use the model to make optimum investment and how to make portfolio combined with clustering analysis is also explained.
文摘The electronic structure and the optical properties of Ca<sub>2</sub>Ge have been calculated by the first-principles pseudo potential method. The results of the electric structure show that Ca<sub>2</sub>Ge bulk is a direct semiconductor with the band gap of 0.306 eV, the conduction band is mainly composed of Ca 3d, the valence bands is mainly composed of Ge 3p. With Sr-doping, Ca<sub>2</sub>Ge bulk is a direct semiconductor with the band gap of 0.350 eV, the conduction bands are mainly composed of Ca 3d and Sr 3d, the valence bands are mainly composed of Ge 3p and Sr 3d. The results of the optical properties show that the dielectric constant of Ca<sub>2</sub>Ge bulk is reduced from 21.52 to 13.94, the reflectivity is decreased, and the absorption is increased with Sr-doping. The optical properties are improved with Sr-doping, the results offer theoretical guide for the optical properties control of Ca<sub>2</sub>Ge.
文摘The histopathological features of the globoid dysplasia of the human gastric epithelium were described in detail and in series by means of observation of serial sections of 61 cases with globoid dys-plasias. Three grades were divided according to the architectural and cellular atypia of the globoid dys-plasias. The penetration of outer layer globoid dys-plastic cells through the basement membrane of 'the structure of double layers' appeared in typical globoid dysplasia grade II and the infiltration of the globoid dysplastic cells into stroma as well as the formation of incipient focus of signet ring cell carcinoma were described. The twinkling scene of the infiltration of the globoid dysplastic cells into lamina propria through the basement membrane, and the destroying of the basement membrane by the globoid dysplastic cells were shown by means of Gordon Sweet's staining. Through the analysis as for the distribution characteristics of ages and sexes in 61 globoid dysplasia cases and 51 signet ring cell carcinomas, a fact was discovered that the mobility of female cases was ten years prior to that of male ones in average. A conclusion could be made that the globoid dysplasia might be an important precan-cerous lesion of the signet ring cell carcinoma of the stomach.
基金support from the Shiraz University(during 2015-2022)Ferdowsi University of Mashhad,Iran(during 2011-2013)the Department of Environment(DOE)for giving permission to AG for sampling(91.51843)。
文摘The closely related Black-headed Bunting(Emberiza melanocephala,a western Palearctic lineage)and Red-headed Bunting(Emberiza bruniceps,an eastern Palearctic lineage)hybridize and replace each other south of the Caspian Sea.The parental species have distinct phenotypes and therefore morphology is useful for assessing hybridization in the contact zone.In the years of 1940 and 1977,quite a few hybrids were collected and studied morphologically.Since then,the hybrid zone appears to have expanded westwards,but there has been a time gap in the collection of morphological data.Here we reanalyze bunting specimens morphologically and compare the historical data with recent data.Morphometric and phenotypic traits from three time periods(1940,1977 and recent)were studied to assess phenotypic variation of hybrids,pattern of hybridization,and transgressive traits in the hybrid zone.Our results show that most of the birds in the hybrid zone exhibit intermediate phenotypes(both colors and morphometric characters),ranging from the pure phenotype of either of the parental species.However,hybridization has also produced novel phenotypes not seen in any of the parents.Using a canonical discriminant function analysis,the morphometric characters separated each parental species and the hybrids quite well.Our results showed morphometric intermediacy of hybrids in accordance with phenotypes.We observe a time trend in which recent hybrids are more similar to Red-headed Buntings phenotypically compared to historical samples.This pattern is likely a signature of a westward expansion of the Red-headed Bunting into the breeding range of the Black-headed Bunting.
基金Sponsored by the Mulfidiscipline Scientific Research Foundation of Harbin Institute of Technology( Grant No. HIT. MD. 2002.28)
文摘Vehicle delay is an important measure to evaluate the signal timings of signalized intersections.When optimization the signal control parameters, delays of vehicles from all approach directions of an intersection should be considered. Based on the analysis of the vehicle delay on an approach of intersection, directed against the typical condition of a congested intersection-over-saturated condition, the paper has analyzed and inferred the intersection delay dynamic formulation, and has established the relation between intersection delay,the signal timings, vehicle arrival rate and the queue lengths, and that provides useful information for understanding vehicle delay of signalized intersection and for establishing performance index function of signal timing optimization.
基金This research is supported by China National Natural Science Foundation (CNNSF), Research Grant No. 50128504
文摘An Inverse perturbation method is described for solving the general inverse eigenvalue problem. By taking the analysis of the rotor system as example based upon FEM, the new inverse perturbation method for structural design with specified low-order natural frequencies or frequency constraint bands is detailed as well as its complete theoretical basis. Moreover, formulations to calculate the inverse perturbation parameter ε and method to select the corresponding ε's value properly are also proposed. The proposed method is characterized in reducing frequency analysis and suitable for large and small structrual changes alike. Finally, several different numerical examples for inverse cigenvalue problem are discussed to illustrate the method, which show that this inverse perturbation method Is general and can be applied to other type of structure or dement.
基金Foundation items: the National Natural Science Foundation of China (40075005) the National Key Basic Research Development Project Program of China (G1998040909)
文摘The aim is to put forward the optimal selecting of weights in variational problemin which the linear advection equation is used as constraint. The selection of the functionalweight coefficients ( FWC) is one of the key problems for the relevant research. It wasarbitrary and subjective to some extent presently. To overcome this difficulty, thereasonable assumptions were given for the observation field and analyzed field, variationalproblems with " weak constraints" and " strong constraints" were considered separately. Bysolving Euler' s equation with the matrix theory and the finite difference method of partialdifferential equation, the objective weight coefficients were obtained in the minimumvariance of the difference between the analyzed field and ideal field. Deduction results showthat theoretically the optimal selection indeed exists in the weighting factors of the costfunction in the means of the minimal variance between the analysis and ideal field in terms ofthe matrix theory and partial differential ( corresponding difference ) equation, if thereasonable assumption from the actual problem is valid and the differnece equation is stable.It may realize the coordination among the weight factors, numerical models and theobservational data. With its theoretical basis as well as its prospects of applications, thisobjective selecting method is probably a way towards the finding of the optimal weightingfactors in the variational problem.
基金National Natural Science Foundation of China(82373829,82273893,82173773)Natural Science Foundation of Guangdong Province,China(2021A1515220099,2022A1515011576)+1 种基金High-End Foreign Experts Project,China(G2021199005L)Science and Technology Program of Guangdong Provincial Medical Products Administration,China(2023TDZ11,2022ZDB04).
文摘The dynamic tracking of antibody‒drug conjugates (ADCs) in serum is crucial. However, a versatile bioanalytical platform is lacking due to serious matrix interferences, the heterogeneity and complex biotransformation of ADCs, and the recognition deficiencies of traditional affinity technologies. To overcome this, a multiepitope recognition technology (MERT) was developed by simultaneously immobilizing CDR and non-CDR ligands onto MOF@AuNPs. MERT's excellent specificity, ultrahigh ligand density, and potential synergistic recognition ability enable it to target the different key regions of ADCs to overcome the deficiencies of traditional technologies. The binding capacity of MERT for antibodies is ten to hundred times higher than that of the mono-epitope or Fc-specific affinity technologies. Since MERT can efficiently capture target ADCs from serum, a novel bioanalytical platform based on MERT and RPLC‒QTOF-MS has been developed to monitor the dynamic changes of ADCs in serum, including the fast changes of drug-to-antibody ratio from 3.67 to 0.22, the loss of payloads (maytansinol), and the unexpected hydrolysis of the succinimide ring of the linker, which will contribute to clarify the fate of ADCs and provide a theoretical basis for future design. In summary, the MERT-based versatile platform will open a new avenue for in-depth studies of ADCs in biological fluids.
基金This work was supported by the National Natural Science Foundation of China(Grant No.40175010)
文摘The detailed kinematic structure of a heavy rain event that occurred in the middle reaches of the Yangtze River was investigated using dual-Doppler radar observation. A variational analysis method was developed to obtain the three-dimensional wind fields. Before the analysis, a data preprocessing procedure was carried out, in which the temporal variation with the scanning time interval and the effect of the earth curvature on the data position were taken into account. The analysis shows that a shear line in the lower and middle levels played an important role in the rainfall event. The precipitation fell mainly on the south end of the shear line where southerly flow prevailed and convergence and updraft were obvious. With the movement and decay of the shear line, the precipitation moved and decayed correspondingly.
基金the financial support from China Postdoctoral Science Foundation(2018M643205)
文摘Tea is a widely consumed beverage and has many important physiological properties and potential health benefits. In this study, a novel method based on supercritical fluid chromatography coupled with mass spectrometry (SFC-MS) was developed to simultaneously determine 11 amino acids in different types of tea (green teas, Oolong tea, black tea and Pu-erh tea). The separation conditions for the analysis of the selected amino acids including the column type, temperature and backpressure as well as the type of additive, were carefully optimized. The best separation of the 11 amino acids was obtained by adding water (5%, v/v) and trifluoroacetic acid (0.4%, v/v) to the organic modifier (methanol). Finally, the developed SFC-MS method was fully validated and successfully applied to the determination of these amino acids in six different tea samples. Good linearity (r ≥ 0.993), precision (RSDs≤ 2.99%), accuracy (91.95%-107.09%) as well as good sample stability were observed. The limits of detection ranged from 1.42 to 14.69 ng/mL, while the limits of quantification were between 4.53 and 47.0 ng/mL. The results indicate that the contents of the 11 amino acids in the six different tea samples are greatly influenced by the degree of fermentation. The proposed SFC-MS method shows a great potential for further investigation of tea varieties.
基金financially supported by the Ministry of Industry and Information Technology of China(No.2012ZX04003011)the National Natural Science Foundation of China(No.51275323)
文摘The purpose of this study was to investigate the effects of Zr interlayer on the structure and mechanical properties of TiAlN films, which were deposited on the M2 high-speed steel substrates by means of plasma-enhanced magnetron sputtering. The result shows that the crystal orientation of Zr/TiAlN films is similar to that of single-layered TiAlN films, but the difference is that AlN(111) of Zr/TiAlN films disappears completely. With respect to Zr interlayer, the texture coefficient of Zr/TiAlN films is approximately 1. Zr/TiAlN films exhibit a compact isometric structure, which is distinctly different from the columnar structure existing in the single-layered TiAlN films and Ti/TiAlN films. The hardness and H3/E*2 of Zr/TiAlN films are, respectively, enhanced to be 36.6 GPa and 0.147. With a few cracks emerging around the indention, the adhesion strength of TiAlN films is obviously advanced by adding Zr metal interlayer.
文摘One of the most important tools used to evaluate kidney function in the context of chronic kidney disease or other renal function related pathologies is the exploration of glomerular filtration rate (GFR). Iohexol is up to this moment a good candidate molecule for the GFR assessment since it exhibits minimum protein binding rates and minimum extra-renal clearance, being neither secreted nor reabsorbed at the tubular level. This study proposes and evaluates a new LC-MS/MS method for the iohexol determination from capillary blood, prelevated using volumetric absorbative microsampling (VAMS) systems. As an alternative to VAMS, a brand new HemaPEN■ device for micro-prelevation was also tested. A new high throughput sample preparation protocol adapted for iohexol quantification from whole blood VAMS samples was developed. The medium term stability study of iohexol in dried whole blood VAMS samples that was conducted showed a good stability of this molecule for up to 12 days. By collecting only 10 mL of blood, iohexol can be analyzed from dried whole blood VAMS samples for concentration ranges between 1 and 250 mg/mL. Due to the analyte stability in VAMS for up to 12 days, this approach might be successfully applied for GFR assessment for clinical cases allowing minimum invasiveness and even delayed analysis.
文摘The technology of Intelligent cure operation is set forth according to developing tendency of smart material and structure. Intelligent-system-based tool was developed in order to operate the autoclave cure of a fiber reinforced thermosetting matrix composite laminate in an optimal manner. The objective function is comforts for minimizing the total cure time, uniforming the temperature distribution, controling exothermal and minimizing the process-induced residual stresses in the laminate. Data is analyzed on-line to determine the trends in real-time. The results from application of this overall strategy for the curing of composites are presented.
