Dear Members of the Editorial Board, Contributors and Friends of the journal,This issue of Earthquake Engineering and Engineering Vibration(Vol. 23, No. 2) includes five papers in a special section entitled “Wave-Bas...Dear Members of the Editorial Board, Contributors and Friends of the journal,This issue of Earthquake Engineering and Engineering Vibration(Vol. 23, No. 2) includes five papers in a special section entitled “Wave-Based Nondestructive Testing and Evaluation Methods in Civil Engineering”. The special section aims to present recent developments and applications of wave-based nondestructive testing and evaluation research. We thank the guest editors, Prof. Nenad Gucunski of Rutgers University, USA, Prof. Lin Shibin of Jianghan University, China and Prof. Chen Hongbing, University of Science and Technology Beijing, China, for their hard work and dedication.展开更多
The morphogenesis of gynoecium is crucial for propagation and productivity of fruit crops.For trioecious papaya(Carica papaya),highly differentiated morphology of gynoecium in flowers of different sex types is control...The morphogenesis of gynoecium is crucial for propagation and productivity of fruit crops.For trioecious papaya(Carica papaya),highly differentiated morphology of gynoecium in flowers of different sex types is controlled by gene networks and influenced by environmental factors,but the regulatory mechanism in gynoecium morphogenesis is unclear.Gynodioecious and dioecious papaya varieties were used for analysis of differentially expressed genes followed by experiments using auxin and an auxin transporter inhibitor.We first compared differential gene expression in functional and rudimentary gynoecium at early stage of their development and detected significant difference in phytohormone modulating and transduction processes,particularly auxin.Enhanced auxin signal transduction in rudimentary gynoecium was observed.To determine the role auxin plays in the papaya gynoecium,auxin transport inhibitor(N-1-Naphthylphthalamic acid,NPA)and synthetic auxin analogs with different concentrations gradient were sprayed to the trunk apex of male and female plants of dioecious papaya.Weakening of auxin transport by 10 mg/L NPA treatment resulted in female fertility restoration in male flowers,while female flowers did not show changes.NPA treatment with higher concentration(30 and 50 mg/L)caused deformed flowers in both male and female plants.We hypothesize that the occurrence of rudimentary gynoecium patterning might associate with auxin homeostasis alteration.Proper auxin concentration and auxin homeostasis might be crucial for functional gynoecium morphogenesis in papaya flowers.These results will lead to further investigation on the auxin homeostasis and gynoecium morphogenesis in papaya.展开更多
A recent review publication presented an extensive and comprehensive assessment of the phenomenological relations of Poisson’s ratios (PRs) to the behavior and responses of contemporary materials under specific loadi...A recent review publication presented an extensive and comprehensive assessment of the phenomenological relations of Poisson’s ratios (PRs) to the behavior and responses of contemporary materials under specific loading conditions. The present review and analysis paper is intended as a theoretical mechanics complement covering mathematical and physical modeling of a single original elastic and of six time and process (i.e. path and stress) dependent viscoelastic PR definitions as well as a seventh special path independent one. The implications and consequences of such models on material characterization are analyzed and summarized. Indeed, PRs based on experimentally obtained 2-D strains under distinct creep and/or relaxation processes exhibit radically different time responses for identical material specimen. These results confirm the PR’s implicit path dependence in addition to their separate intrinsic time reliance. Such non-uniqueness of viscoelastic PRs renders them unsuitable as universal material descriptors. Analytical formulations and experimental measurements also examine the physical impossibility of instantaneously achieving time independent loads or strains or their rates thus making certain PR definitions based on constant state variables, while mathematically valid, physically unrealistic and unachievable. A newly developed theoretical/experimental protocol for the determination of the time when loading patterns reach stead-state conditions based on strain accelerations demonstrates the capability to measure this time from experimental data. Due to the process dependent PRs, i.e. stress and stress history paths, the non-existence of a unique viscoelastic PR and of a universal elastic-viscoelastic correspondence principle or analogy (EVCP) in terms of PRs is demonstrated. Additionally and independently, the required double convolution integral construction of linear viscoelastic constitutive relations with the inclusion of PRs is cumbersome analytically and computationally needlessly highly CPU intensive. Furthermore, there is no theoretical fundamental hint as to what loading path is required to produce a unique universal viscoelastic PR definition necessary for formulating a PR based constitutive relation or an EVCP protocol. The analysis associated with an additional Class VII viscoelastic PR establishes it as a universal representation which is loading path and strain independent while still remaining time dependent. This Class PR can be the one used if it is desired to express constitutive relations in terms of PRs, subject to the caveat applying to all PR Classes regarding the CPU intensiveness in the time space due to triple product and double convolution integral constitutive relations. However, the use PRs is unnecessary since any set of material behavior can be uniquely and completely defined in terms of only moduli and/or compliances. The mathematical model of instantaneous initial loading paths, based on Heavi-side functions, is examined in detail and shown to lead to infinite velocities and accelerations. Additionally, even if non-instantaneous gradual loading functions are employed the resulting PRs are still load and load history dependent. Consequently, they represent specialized PR responses applicable and limited to those particular load and history combinations. Although the analyses contained herein are generalized to non-homogeneous linear viscoelastic materials, the main focus is on PR time and process dependence. The non-homogeneous material results and conclusions presented herein apply equally to homogeneous viscoelasticity and per se do not influence the results or conclusions of the analytical development regarding viscoelastic PRs. In short, these PR analyses apply to all linear viscoelastic material characterization.展开更多
Separate sexes in dioecious plants display different morphology and physiological characteristics.The differences between the two sexes lie in their highly differentiated floral characteristics and in sex-related phen...Separate sexes in dioecious plants display different morphology and physiological characteristics.The differences between the two sexes lie in their highly differentiated floral characteristics and in sex-related phenotype,which is genetically determined and epigenetically modified.In dioecious papaya(Carica papaya L.),global comparisons of epigenetic DNA methylation and gene expressions were still limited.We conducted bisulfite sequencing of early-stage flowers grown in three seasons(spring,summer and winter)and compared their methylome and transcriptome profiles to investigate the differential characteristics of male and female in papaya.Methylation variances between female and male papaya were conserved among three different seasons.However,combined genome-scale transcriptomic evidence revealed that most methylation variances did not have influence on the expression profiles of neighboring genes,and the differentially expressed genes were most overrepresented in phytohormone signal transduction pathways.Further analyses showed diverse stress-responsive methylation alteration in male and female flowers.Male flower methylation was more responsive to stress whereas female flower methylation varied less under stress.Early flowering of male papaya in spring might be associated with the variation in the transcription of CpSVP and CpAP1 coinciding with their gene-specific hypomethylation.These findings provide insights into the sex-specific DNA methylation and gene expression landscapes of dioecious papaya and a foundation to investigate the correlation between differentiated floral characteristics and their candidate genes.展开更多
Sex types of papaya are controlled by a pair of nascent sex chromosomes,but molecular genetic mechanisms of sex determination and sex differentiation in papaya are still unclear.We performed comparative analysis of tr...Sex types of papaya are controlled by a pair of nascent sex chromosomes,but molecular genetic mechanisms of sex determination and sex differentiation in papaya are still unclear.We performed comparative analysis of transcriptomic profiles of male and female floral buds at the early development stage before the initiation of reproductive organ primordia at which there is no morphological difference between male and female flowers.A total of 1734 differentially expressed genes(DEGs)were identified,of which 923 showed female-biased expression and 811 showed male-biased expression.Functional annotation revealed that genes related to plant hormone biosynthesis and signaling pathways,especially in abscisic acid and auxin pathways,were overrepresented in the DEGs.Transcription factor binding motifs,such as MYB2,GAMYB,and AP2/EREBP,were enriched in the promoters of the hormone-related DEGs,and transcription factors with those motifs also exhibited differential expression between sex types.Among these DEGs,we also identified 11 genes in the non-recombining region of the papaya sex chromosomes and 9 genes involved in stamen and carpel development.Our results suggested that sex differentiation in papaya may be regulated by multiple layers of regulation and coordination and involved transcriptional,epigenetic,and phytohormone regulation.Hormones,especially ABA and auxin,transcription factors,and genes in the non-recombination region of the sex chromosome could be involved in this process.Our findings may facilitate the elucidation of signal transduction and gene interaction in sex differentiation of unisexual flowers in papaya.展开更多
文摘Dear Members of the Editorial Board, Contributors and Friends of the journal,This issue of Earthquake Engineering and Engineering Vibration(Vol. 23, No. 2) includes five papers in a special section entitled “Wave-Based Nondestructive Testing and Evaluation Methods in Civil Engineering”. The special section aims to present recent developments and applications of wave-based nondestructive testing and evaluation research. We thank the guest editors, Prof. Nenad Gucunski of Rutgers University, USA, Prof. Lin Shibin of Jianghan University, China and Prof. Chen Hongbing, University of Science and Technology Beijing, China, for their hard work and dedication.
基金supported by startup fund from Fujian Agriculture and Forestry University and the NSF Plant Genome Research Program Award 1546890.It was also supported by National Natural Science Foundation of China(31701889)Natural Science Foundation of Fujian Province of China(2018J01601).
文摘The morphogenesis of gynoecium is crucial for propagation and productivity of fruit crops.For trioecious papaya(Carica papaya),highly differentiated morphology of gynoecium in flowers of different sex types is controlled by gene networks and influenced by environmental factors,but the regulatory mechanism in gynoecium morphogenesis is unclear.Gynodioecious and dioecious papaya varieties were used for analysis of differentially expressed genes followed by experiments using auxin and an auxin transporter inhibitor.We first compared differential gene expression in functional and rudimentary gynoecium at early stage of their development and detected significant difference in phytohormone modulating and transduction processes,particularly auxin.Enhanced auxin signal transduction in rudimentary gynoecium was observed.To determine the role auxin plays in the papaya gynoecium,auxin transport inhibitor(N-1-Naphthylphthalamic acid,NPA)and synthetic auxin analogs with different concentrations gradient were sprayed to the trunk apex of male and female plants of dioecious papaya.Weakening of auxin transport by 10 mg/L NPA treatment resulted in female fertility restoration in male flowers,while female flowers did not show changes.NPA treatment with higher concentration(30 and 50 mg/L)caused deformed flowers in both male and female plants.We hypothesize that the occurrence of rudimentary gynoecium patterning might associate with auxin homeostasis alteration.Proper auxin concentration and auxin homeostasis might be crucial for functional gynoecium morphogenesis in papaya flowers.These results will lead to further investigation on the auxin homeostasis and gynoecium morphogenesis in papaya.
文摘A recent review publication presented an extensive and comprehensive assessment of the phenomenological relations of Poisson’s ratios (PRs) to the behavior and responses of contemporary materials under specific loading conditions. The present review and analysis paper is intended as a theoretical mechanics complement covering mathematical and physical modeling of a single original elastic and of six time and process (i.e. path and stress) dependent viscoelastic PR definitions as well as a seventh special path independent one. The implications and consequences of such models on material characterization are analyzed and summarized. Indeed, PRs based on experimentally obtained 2-D strains under distinct creep and/or relaxation processes exhibit radically different time responses for identical material specimen. These results confirm the PR’s implicit path dependence in addition to their separate intrinsic time reliance. Such non-uniqueness of viscoelastic PRs renders them unsuitable as universal material descriptors. Analytical formulations and experimental measurements also examine the physical impossibility of instantaneously achieving time independent loads or strains or their rates thus making certain PR definitions based on constant state variables, while mathematically valid, physically unrealistic and unachievable. A newly developed theoretical/experimental protocol for the determination of the time when loading patterns reach stead-state conditions based on strain accelerations demonstrates the capability to measure this time from experimental data. Due to the process dependent PRs, i.e. stress and stress history paths, the non-existence of a unique viscoelastic PR and of a universal elastic-viscoelastic correspondence principle or analogy (EVCP) in terms of PRs is demonstrated. Additionally and independently, the required double convolution integral construction of linear viscoelastic constitutive relations with the inclusion of PRs is cumbersome analytically and computationally needlessly highly CPU intensive. Furthermore, there is no theoretical fundamental hint as to what loading path is required to produce a unique universal viscoelastic PR definition necessary for formulating a PR based constitutive relation or an EVCP protocol. The analysis associated with an additional Class VII viscoelastic PR establishes it as a universal representation which is loading path and strain independent while still remaining time dependent. This Class PR can be the one used if it is desired to express constitutive relations in terms of PRs, subject to the caveat applying to all PR Classes regarding the CPU intensiveness in the time space due to triple product and double convolution integral constitutive relations. However, the use PRs is unnecessary since any set of material behavior can be uniquely and completely defined in terms of only moduli and/or compliances. The mathematical model of instantaneous initial loading paths, based on Heavi-side functions, is examined in detail and shown to lead to infinite velocities and accelerations. Additionally, even if non-instantaneous gradual loading functions are employed the resulting PRs are still load and load history dependent. Consequently, they represent specialized PR responses applicable and limited to those particular load and history combinations. Although the analyses contained herein are generalized to non-homogeneous linear viscoelastic materials, the main focus is on PR time and process dependence. The non-homogeneous material results and conclusions presented herein apply equally to homogeneous viscoelasticity and per se do not influence the results or conclusions of the analytical development regarding viscoelastic PRs. In short, these PR analyses apply to all linear viscoelastic material characterization.
基金supported by startup fund from Fujian Agriculture and Forestry University and the NSF Plant Genome Research Program Award 1546890.
文摘Separate sexes in dioecious plants display different morphology and physiological characteristics.The differences between the two sexes lie in their highly differentiated floral characteristics and in sex-related phenotype,which is genetically determined and epigenetically modified.In dioecious papaya(Carica papaya L.),global comparisons of epigenetic DNA methylation and gene expressions were still limited.We conducted bisulfite sequencing of early-stage flowers grown in three seasons(spring,summer and winter)and compared their methylome and transcriptome profiles to investigate the differential characteristics of male and female in papaya.Methylation variances between female and male papaya were conserved among three different seasons.However,combined genome-scale transcriptomic evidence revealed that most methylation variances did not have influence on the expression profiles of neighboring genes,and the differentially expressed genes were most overrepresented in phytohormone signal transduction pathways.Further analyses showed diverse stress-responsive methylation alteration in male and female flowers.Male flower methylation was more responsive to stress whereas female flower methylation varied less under stress.Early flowering of male papaya in spring might be associated with the variation in the transcription of CpSVP and CpAP1 coinciding with their gene-specific hypomethylation.These findings provide insights into the sex-specific DNA methylation and gene expression landscapes of dioecious papaya and a foundation to investigate the correlation between differentiated floral characteristics and their candidate genes.
基金This work was supported by the grant 2015N20002-1 from the Department of Science and Technology of Fujian Province to RM,US National Science Foundation(NSF)Plant Genome Research Program Award DBI-1546890 to R.Mthe scholarship 201608350085 from China Scholarship Council to JL.
文摘Sex types of papaya are controlled by a pair of nascent sex chromosomes,but molecular genetic mechanisms of sex determination and sex differentiation in papaya are still unclear.We performed comparative analysis of transcriptomic profiles of male and female floral buds at the early development stage before the initiation of reproductive organ primordia at which there is no morphological difference between male and female flowers.A total of 1734 differentially expressed genes(DEGs)were identified,of which 923 showed female-biased expression and 811 showed male-biased expression.Functional annotation revealed that genes related to plant hormone biosynthesis and signaling pathways,especially in abscisic acid and auxin pathways,were overrepresented in the DEGs.Transcription factor binding motifs,such as MYB2,GAMYB,and AP2/EREBP,were enriched in the promoters of the hormone-related DEGs,and transcription factors with those motifs also exhibited differential expression between sex types.Among these DEGs,we also identified 11 genes in the non-recombining region of the papaya sex chromosomes and 9 genes involved in stamen and carpel development.Our results suggested that sex differentiation in papaya may be regulated by multiple layers of regulation and coordination and involved transcriptional,epigenetic,and phytohormone regulation.Hormones,especially ABA and auxin,transcription factors,and genes in the non-recombination region of the sex chromosome could be involved in this process.Our findings may facilitate the elucidation of signal transduction and gene interaction in sex differentiation of unisexual flowers in papaya.
