Nucleotide-binding domain leucine-rich repeat receptors (NLRs) play important roles in the innate... more Nucleotide-binding domain leucine-rich repeat receptors (NLRs) play important roles in the innate immune systems of both plants and animals. Recent breakthroughs in NLR biochemistry and biophysics have revolutionized our understanding of how NLR proteins function in plant immunity. In this review, we summarize the latest findings in plant NLR biology and draw direct comparisons to NLRs of animals. We discuss different mechanisms by which NLRs recognize their ligands in plants and animals. The discovery of plant NLR resistosomes that assemble in a comparable way to animal inflammasomes reinforces the striking similarities between the formation of plant and animal NLR complexes. Furthermore, we discuss the mechanisms by which plant NLRs mediate immune responses and draw comparisons to similar mechanisms identified in animals. Finally, we summarize the current knowledge of the complex genetic architecture formed by NLRs in plants and animals and the roles of NLRs beyond pathogen detection.
Both plants and animals rely on nucleotide-binding domain leucine-rich repeat-containing (NLR)... more Both plants and animals rely on nucleotide-binding domain leucine-rich repeat-containing (NLR) proteins to respond to invading pathogens and activate immune responses. An emerging concept in NLR biology is that “sensor” NLR proteins are often paired with “helper” NLR proteins to mediate immune signalling. However, the degree to which NLRs form signalling networks beyond sensor and helper pairs is poorly understood. In this thesis, I discovered that a large NLR immune signalling network with a complex architecture mediates immunity to oomycetes, bacteria, viruses, nematodes, and insects. Helper NLRs in the NRC (NLR-required for cell death) family are functionally redundant but display distinct specificities towards diverse sensor NLRs. Several sensor NLRs, including Rx, Bs2 and Sw5b, signal via interchangeable NRC2, NRC3 or NRC4, whereas some other sensor NLRs have a more limited downstream spectrum. For example, Prf signals via interchangeable NRC2 or NRC3 but not NRC4, and Rpi-...
This paper presents an Improved Bayesian Optimization (IBO) algorithm to solve complex high-dimen... more This paper presents an Improved Bayesian Optimization (IBO) algorithm to solve complex high-dimensional epidemic models' optimal control solution. Evaluating total objective function value for disease control models with hundreds of thousands of control time-periods is high computational cost. In this paper, we improve the conventional Bayesian Optimization (BO) approach from two parts. The existing BO methods optimize the minimizer step for once time during each acquisition function update process. To find a better solution for each acquisition function update, we do more local minimization steps to tune the algorithm. When the model is high dimensions, and the objective function is complicated, only some update iterations of the acquisition function may not find the global optimal solution. The IBO algorithm adds a series of Adam-based steps at the final stage of the algorithm to increase the solution's accuracy. Comparative simulation experiments using different kernel fu...
Rapid (co-)evolution at multiple timescales is a hallmark of plant-microbe interactions. The mech... more Rapid (co-)evolution at multiple timescales is a hallmark of plant-microbe interactions. The mechanistic basis for the rapid evolution largely rests on the features of the genomes of the interacting partners involved. Here, we review recent insights in genomic characteristics and mechanisms that enable rapid evolution of both plants and phytopathogens. These comprise fresh insights in allelic series of matching pairs of resistance and avirulence genes, the generation of novel pathogen effectors, the recently recognized small RNA warfare, and genomic aspects of secondary metabolite biosynthesis. In addition, we discuss the putative contributions of permissive host environments, transcriptional plasticity and the role of ploidy on the interactions. We conclude that the means underlying the rapid evolution of plantmicrobe interactions are multifaceted and depend on the particular nature of each interaction.
ABSTRACT A study was conducted to determine the effect of concrete release strength on the develo... more ABSTRACT A study was conducted to determine the effect of concrete release strength on the development length and flexural capacity of members utilizing five different 5.32-mm-diameter prestressing wires that are commonly used in the manufacture of prestressed concrete railroad ties worldwide. These included two chevron-indented wires with different indent depths, one spiral-indented wire, one dot-indented wire, and one smooth wire (with no surface indentation). A consistent concrete mixture was used for the manufacture of all test specimens, and the different release strengths were obtained by allowing the specimens to cure for different amounts of time prior to de-tensioning. Each prismatic specimen (prism) had a 3.5 " (88.9 mm) x 3.5 " (88.9 mm) square cross section with four wires arranged symmetrically. The prisms were identical except for the wire type and the compressive strength at the time of de-tensioning. All four wires were each initially tensioned to 7000 pounds (31.14 KN) and then de-tensioned gradually when the concrete compressive strength reached 3500 (24.13 MPa), 4500 (31.03 MPa) and 6000 (41.37 MPa) psi. Precise de-tensioning strengths were ensured by testing 4-in.-diameter (101.6 mm) x 8-in.-long (203.2 mm) compression strength cylinders that were temperature match-cured. The prisms were loaded in 3-point-bending to determine the ultimate bond characteristics of each reinforcement type for the different concrete release strengths. A loading rate of 300 lb/min (1334 N/min) was applied at mid-span and the maximum sustained moment was calculated for each test. Two 69-in.-long (175.26 cm) prisms, each having different concrete release strength, were tested with each of the 5 wire types. These prisms were tested at both ends, with a different embedment length assessed at each end. Thus, for each wire type and concrete release strength evaluated, a total of 4 tests were conducted for a total of 60 tests (5 wire types x 3 release strengths x 4 tested embedment lengths). Test results indicate that the concrete compressive strength at de-tensioning can have a direct iMPact on the ultimate flexural capacity of the members, and this has significant design implications for pretensioned concrete railroad ties. Results are discussed and recommendations made. INTRODUCTION The first major utilization of prestressed concrete ties in North America was in 1966 (Hanna, 1979). The main tasks of railroad ties as an integral part of railroad track include preventing rails from any lateral or longitudinal displacements. Thus, the main function of railroad ties is stabilization of rails [1]. The use of prestressed concrete railroad ties is growing in the United States as the railroad industry is becoming more efficient. This growing is justified by many desirable features over wood crossties, including long life expectancy, environmental friendliness and reduction in fuel consumption of trains [2, 3]. Records to date show that pretensioned concrete crossties have brought more economical design and better structural behavior which improves the overall stability and performance of the railroad track [4]. In pretensioned concrete members, the total prestress force fully transfers to the surrounding concrete by the bond
SummaryNonhost resistance (NHR) is a robust plant immune response against non‐adapted pathogens. ... more SummaryNonhost resistance (NHR) is a robust plant immune response against non‐adapted pathogens. A number of nucleotide‐binding leucine‐rich repeat (NLR) proteins that recognize non‐adapted pathogens have been identified, although the underlying molecular mechanisms driving robustness of NHR are still unknown. Here, we screened 57 effectors of the potato late blight pathogen Phytophthora infestans in nonhost pepper (Capsicum annuum) to identify avirulence effector candidates. Selected effectors were tested against 436 genome‐wide cloned pepper NLRs, and we identified multiple functional NLRs that recognize P. infestans effectors and confer disease resistance in the Nicotiana benthamiana as a surrogate system. The identified NLRs were homologous to known NLRs derived from wild potatoes that recognize P. infestans effectors such as Avr2, Avrblb1, Avrblb2, and Avrvnt1. The identified CaRpi‐blb2 is a homologue of Rpi‐blb2, recognizes Avrblb2 family effectors, exhibits feature of lineage‐specifically evolved gene in microsynteny and phylogenetic analyses, and requires pepper‐specific NRC (NLR required for cell death)‐type helper NLR for proper function. Moreover, CaRpi‐blb2–mediated hypersensitive response and blight resistance were more tolerant to suppression by the PITG_15 278 than those mediated by Rpi‐blb2. Combined results indicate that pepper has stacked multiple NLRs recognizing effectors of non‐adapted P. infestans, and these NLRs could be more tolerant to pathogen‐mediated immune suppression than NLRs derived from the host plants. Our study suggests that NLRs derived from nonhost plants have potential as untapped resources to develop crops with durable resistance against fast‐evolving pathogens by stacking the network of nonhost NLRs into susceptible host plants.
Abstract Bacterial speck, caused by the pathogen Pseudomonas syringae pv. tomato, is one of the m... more Abstract Bacterial speck, caused by the pathogen Pseudomonas syringae pv. tomato, is one of the most common diseases in tomato production. Together with Pto kinase, the NLR (nucleotide-binding domain leucine-rich repeat containing) protein Prf confers resistance against the bacterial speck pathogen by recognizing AvrPto and AvrPtoB, two Type III effector proteins secreted by P. syringae pv. tomato. This Prf/Pto pathway is part of a complex NLR network in solanaceous plants that mediates resistance to diverse pathogens through the helper NLR proteins NRCs (NLR required for cell death). We previously showed that, in Nicotiana benthamiana, the hypersensitive cell death elicited by expression of AvrPto and Pto, which activate immunity through the endogenous Prf ortholog NbPrf, requires functionally redundant NRC2 and NRC3. However, whether tomato (Solanum lycopersicum) Prf (SlPrf) confers resistance to the bacterial speck pathogen through NRC2 and NRC3 has not been determined. In this study, we show that SlPrf requires NRC2 and NRC3 to trigger hypersensitive cell death and disease resistance in both N. benthamiana and tomato. We found that the hypersensitive cell death induced by AvrPtoB/Pto/SlPrf in N. benthamiana is compromised when NRC2 and NRC3 are silenced, indicating that SlPrf is an NRC2/3-dependent NLR. We validated this finding by showing that silencing NRC2 and NRC3 in the bacterial speck resistant tomato ‘Rio Grande 76R’ compromised Prf-mediated resistance. These results indicate that the NRC network extends beyond N. benthamiana to solanaceous crops.
ABSTRACT An experimental testing program was conducted at Kansas State University (KSU) to test t... more ABSTRACT An experimental testing program was conducted at Kansas State University (KSU) to test the bond characteristics of various 5.32 mm-diameter, Grade 270 low-relaxation steel wires used in prestressed concrete railroad ties. This un-tensioned pullout test could serve as a quality control test similar to the NASP (North American Strand Producers) Strand Bond Test that has been developed for pre-tensioned strands. A total of twelve (12) wires produced by six different steel manufacturers were used to develop the wire pullout test. All of the wires were tested in their " as-received " condition and have different indent geometries. It is generally accepted that indentations in the wire improve the bond between the steel and concrete. However, there are currently no commonly accepted quality control tests that accurately predict a wire's bond characteristics in a pre-tensioned application. The un-tensioned pullout test developed is comparable to the NASP [Strand] Bond Test. The specimens consist of a 4 in. (100 mm) outer-diameter tube with a total length of 8 in. (200 mm) and a steel plate welded to the bottom. The 5.32 mm-diameter wire was centered in the tube and the sand-cement mortar was placed and allowed to cure. The flow of the mortar was measured for consistency and 2 " x 2 " (50 mm x 50 mm) mortar cubes were used to determine the compressive strength of the mortar. The specimens were tested when the compressive strength of the mortar was between 4500 and 5000 psi (31.0 MPa and 34.5 MPa). Each batch of mortar contained 12 pullout specimens; one with each wire type. Each wire was tested six times leading to a total of six batches and a total of 72 mortar specimens. During testing, the wires were loaded in force control at the bottom, while continuously monitoring and recording the movement (slip) of the wire with respect to the mortar at the opposite (top) end. The force verses end-slip data of the six tests for each wire type were numerically combined to obtain the average bond performance. These average results from the un-tensioned pullout tests were then compared to transfer length measurements from accompanying pre-tensioned concrete prisms. In general, the wire end slip measurements from the pullout tests were found to have good correlation with the measured transfer length. For all 12 wires, a coefficient of determination (R 2) of 0.872 was found between the average pullout force (at 0.10-inch (2.54 mm) of wire free-end slip) and average transfer length measurements from the accompanying concrete prism tests. However, when only the indented wires were considered, the R 2 increased to 0.913.
At present, high dimensional global optimization problems with time-series models have received m... more At present, high dimensional global optimization problems with time-series models have received much attention from engineering fields. Bayesian optimization has quickly become a popular and promising approach for solving global optimization problems since it was proposed. However, the standard Bayesian optimization algorithm is insufficient to solving the global optimal solution when the model is high-dimensional. Hence, this paper presents a novel high dimensional Bayesian optimization algorithm by considering dimension reduction and different dimension fill-in strategies. Most existing literature about Bayesian optimization algorithms did not discuss the sampling strategies to optimize the acquisition function. This study proposed a new sampling method based on both the multiarmed bandit and random search methods while optimizing the acquisition function. Besides, based on the timedependent or dimension-dependent characteristics of the model, the proposed algorithm can reduce the dimension evenly. Then, five different dimension fill-in strategies were discussed and compared in this study. Finally, to increase the final accuracy of the optimal solution, the proposed algorithm adds a local search based on a series of Adam-based steps at the final stage. Our computational experiments demonstrated that the proposed Bayesian optimization algorithm could achieve reasonable solutions with excellent performances for high dimensional global optimization problems with a time-series optimal control model.
A comprehensive study was conducted to determine the variation in transfer length of pre-tensione... more A comprehensive study was conducted to determine the variation in transfer length of pre-tensioned prestressed concrete railroad ties with different parameters, including prestressing steel type and concrete variables. The in-depth evaluation included different prestressing reinforcement types that are employed in concrete railroad ties worldwide. The study consisted of two phases; Lab-Phase and Plant-Phase. Throughout the study, transfer lengths were determined from surface strain measurements of pre-tensioned concrete members. During the Lab-Phase, pre-tensioned concrete prisms were fabricated to replicate plant manufactured crossties. Different groups of prisms were fabricated during this phase, with each group used to determine the influence of selected prestressing steel or concrete variables on transfer length. A special jacking arrangement was employed to ensure that each of the reinforcements was tensioned to the same force. During the Lab-Phase, an 8-inch Whittemore gage was utilized to determine concrete surface displacements and thereby calculate surface strains. Later, during the Plant-Phase, pre-tensioned concrete railroad ties were fabricated at a concrete crosstie manufacturing plant with the same group of reinforcements. In-plant concrete surface strains were determined by utilizing both the Whittemore gage and two automated laserspeckle imaging (LSI) devices. Later, a long-term study was conducted on plant-manufactured crossties that were cast exclusively to utilize the mechanical (Whittemore) gage system. Various results from both the Lab-Phase and Plant-Phase are presented along with discussion. Potential benefits of laboratory prisms in estimating transfer lengths is also discussed. Results from both phases indicated that large variations in transfer lengths are due primarily to variations in the bond quality of the different prestressing tendons and the concrete strength at detensioning. Results pertaining to the variation in bond quality due to other concrete variables are also presented. A comprehensive study of prestressing steel and concrete variables affecting transfer length in pre-tensioned concrete crossties
Communications in Nonlinear Science and Numerical Simulation, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
This article presents two new mathematical models, an information forgetting curve (IFC) model an... more This article presents two new mathematical models, an information forgetting curve (IFC) model and a memory reception fading and cumulating (MRFC) model, to examine forgetting and learning behaviors of individuals during an infectious disease epidemic. Both models consider how epidemic prevalence and community behaviorchange information may affect agent emotions and subsequently influence an individual's behavior changes during an epidemic. The IFC model utilizes a forgetting curve to process epidemic information, and the MRFC model formulates disease information variations using the Itô diffusion process. Sensitivity analysis and simulation comparisons showed that the MRFC model more accurately describes the epidemic with high lethal rate gets high attention. The author also demonstrated that MRFC model has higher sensitivity parameters and is more flexible on wide ranges of infection rates than the IFC model. However, the IFC model is a better suited for widespread, low-risk mortality epidemics, such as seasonal influenza, the infection information and protective behavior have close relationships among the susceptible population. An agent-based simulation model also developed to mimic the epidemic prevalence of the 2009 Chicago H1N1 using public available historical data sets by IFC model.
International Journal of Modelling and Simulation, 2016
Patients who have sepsis are most likely to suffer from organ dysfunction. Organ dysfunction caus... more Patients who have sepsis are most likely to suffer from organ dysfunction. Organ dysfunction caused by sepsis results in high mortality rate and health care financial loss. The complexity of sepsis results in various dynamic patterns of sepsis for individual patients. Agent-based models provide a means to capture complex information in sepsis development by synthesizing concepts of sepsis progression to a model. Compared to a traditional mathematical modeling approach, agent-based models map interactions among agents to interactions among cells by embedding spatial effect, stochastic nature, and dynamics transitions, thereby demonstrating suitability for the development of complex biological processes. This article presents an integrated-mathematical-multi-agent-based model (IMMAB) to model and simulate acute inflammatory response (AIR), an initial stage of sepsis progression. To our knowledge, this IMMAB is the first version of an agent-based model that measures quantitative levels of indicators in sepsis progression by incorporating experimental data. Despite abstraction and generality, our simulated results reproduced dynamic patterns of AIR progression reported in existing experimental studies. Furthermore, our IMMAB captured diverged outcomes of individual patients when initial loads of pathogen are from 300 to 1000 numerical count. In the end, we inferred that Monocyte and IL-10 are possibly potential therapeutic targets in pre-clinic experiments.
This paper proposes a new, information-transmission-based behavior-switch that applies the indivi... more This paper proposes a new, information-transmission-based behavior-switch that applies the individual fear factor (IFF) to describe how information regarding current disease epidemics can cause human behavior change in a disease-dynamic system. This research is a first attempt to mathematically model how an individual's emotions influence behavior. The approach can be used to study the relationship of information dissemination (e.g., broadcasting, public health education, news media, etc.) and human behaviors during disease outbreaks. The expression of IFF and a mathematical IFF model that combines human behaviors with a classic SIR model is presented, and an optimal strategy that reduces the number of infected individuals and financial loss due to switch behaviors is proposed. In particular, model stability is analyzed and corresponding necessary conditions are determined. This novel modeling approach shows that information transmission influence individual fear, resulting in a variety of human behaviors and leading to numerous disease consequences.
Concrete railroad ties have been used in increasing numbers in the U.S., particularly in high-spe... more Concrete railroad ties have been used in increasing numbers in the U.S., particularly in high-speed rail, heavy-haul freight lines, and new track construction because of their reduced deflections, durability, and competitive cost. In-track assessment of concrete railroad ties can be a challenge, however because many exterior tie surfaces are covered by tie pads and rail or ballast. This damage may include concrete section wear from abrasion, cracking, or crumbling, or other types of defects. Damage internal to the concrete can also not be seen visually. The time and cost needed to inspect these tie surfaces means that it is not routinely performed. Non-destructive testing offers promise as a way to assess concrete tie integrity without having to remove ballast, however more information is needed to know how well non-destructive techniques work in detecting damage. Two of the most promising techniques for investigating the integrity of concrete non-destructively are ultrasonic pulse ...
During January 2013, concrete railroad ties were cast at a tie manufacturing plant with fifteen d... more During January 2013, concrete railroad ties were cast at a tie manufacturing plant with fifteen different reinforcement types that are widely employed in manufacturing of railroad ties worldwide. Among these reinforcements; there were 12 different 5.32 mm diameter wires with various surface indent geometries, two different 7-wire strands with 3/8-inch diameter, and one 3-wire strand with 5/16-inch diameter. Four concrete ties were cast for each reinforcement type for a total of 60 concrete ties. Among the four ties for each reinforcement type, two ties were installed in track and subjected to a cumulative in-track loading of 85 million gross tons (MGT). Before being subjected to this loading, special surface preparation was done on the ties to protect the strain measuring points on the bottom surface of the ties from surface abrasion during loading. The other two ties, which are companion ties for each reinforcement type, were not subjected to any loading. Surface strains of concret...
Nucleotide-binding domain leucine-rich repeat receptors (NLRs) play important roles in the innate... more Nucleotide-binding domain leucine-rich repeat receptors (NLRs) play important roles in the innate immune systems of both plants and animals. Recent breakthroughs in NLR biochemistry and biophysics have revolutionized our understanding of how NLR proteins function in plant immunity. In this review, we summarize the latest findings in plant NLR biology and draw direct comparisons to NLRs of animals. We discuss different mechanisms by which NLRs recognize their ligands in plants and animals. The discovery of plant NLR resistosomes that assemble in a comparable way to animal inflammasomes reinforces the striking similarities between the formation of plant and animal NLR complexes. Furthermore, we discuss the mechanisms by which plant NLRs mediate immune responses and draw comparisons to similar mechanisms identified in animals. Finally, we summarize the current knowledge of the complex genetic architecture formed by NLRs in plants and animals and the roles of NLRs beyond pathogen detection.
Both plants and animals rely on nucleotide-binding domain leucine-rich repeat-containing (NLR)... more Both plants and animals rely on nucleotide-binding domain leucine-rich repeat-containing (NLR) proteins to respond to invading pathogens and activate immune responses. An emerging concept in NLR biology is that “sensor” NLR proteins are often paired with “helper” NLR proteins to mediate immune signalling. However, the degree to which NLRs form signalling networks beyond sensor and helper pairs is poorly understood. In this thesis, I discovered that a large NLR immune signalling network with a complex architecture mediates immunity to oomycetes, bacteria, viruses, nematodes, and insects. Helper NLRs in the NRC (NLR-required for cell death) family are functionally redundant but display distinct specificities towards diverse sensor NLRs. Several sensor NLRs, including Rx, Bs2 and Sw5b, signal via interchangeable NRC2, NRC3 or NRC4, whereas some other sensor NLRs have a more limited downstream spectrum. For example, Prf signals via interchangeable NRC2 or NRC3 but not NRC4, and Rpi-...
This paper presents an Improved Bayesian Optimization (IBO) algorithm to solve complex high-dimen... more This paper presents an Improved Bayesian Optimization (IBO) algorithm to solve complex high-dimensional epidemic models' optimal control solution. Evaluating total objective function value for disease control models with hundreds of thousands of control time-periods is high computational cost. In this paper, we improve the conventional Bayesian Optimization (BO) approach from two parts. The existing BO methods optimize the minimizer step for once time during each acquisition function update process. To find a better solution for each acquisition function update, we do more local minimization steps to tune the algorithm. When the model is high dimensions, and the objective function is complicated, only some update iterations of the acquisition function may not find the global optimal solution. The IBO algorithm adds a series of Adam-based steps at the final stage of the algorithm to increase the solution's accuracy. Comparative simulation experiments using different kernel fu...
Rapid (co-)evolution at multiple timescales is a hallmark of plant-microbe interactions. The mech... more Rapid (co-)evolution at multiple timescales is a hallmark of plant-microbe interactions. The mechanistic basis for the rapid evolution largely rests on the features of the genomes of the interacting partners involved. Here, we review recent insights in genomic characteristics and mechanisms that enable rapid evolution of both plants and phytopathogens. These comprise fresh insights in allelic series of matching pairs of resistance and avirulence genes, the generation of novel pathogen effectors, the recently recognized small RNA warfare, and genomic aspects of secondary metabolite biosynthesis. In addition, we discuss the putative contributions of permissive host environments, transcriptional plasticity and the role of ploidy on the interactions. We conclude that the means underlying the rapid evolution of plantmicrobe interactions are multifaceted and depend on the particular nature of each interaction.
ABSTRACT A study was conducted to determine the effect of concrete release strength on the develo... more ABSTRACT A study was conducted to determine the effect of concrete release strength on the development length and flexural capacity of members utilizing five different 5.32-mm-diameter prestressing wires that are commonly used in the manufacture of prestressed concrete railroad ties worldwide. These included two chevron-indented wires with different indent depths, one spiral-indented wire, one dot-indented wire, and one smooth wire (with no surface indentation). A consistent concrete mixture was used for the manufacture of all test specimens, and the different release strengths were obtained by allowing the specimens to cure for different amounts of time prior to de-tensioning. Each prismatic specimen (prism) had a 3.5 " (88.9 mm) x 3.5 " (88.9 mm) square cross section with four wires arranged symmetrically. The prisms were identical except for the wire type and the compressive strength at the time of de-tensioning. All four wires were each initially tensioned to 7000 pounds (31.14 KN) and then de-tensioned gradually when the concrete compressive strength reached 3500 (24.13 MPa), 4500 (31.03 MPa) and 6000 (41.37 MPa) psi. Precise de-tensioning strengths were ensured by testing 4-in.-diameter (101.6 mm) x 8-in.-long (203.2 mm) compression strength cylinders that were temperature match-cured. The prisms were loaded in 3-point-bending to determine the ultimate bond characteristics of each reinforcement type for the different concrete release strengths. A loading rate of 300 lb/min (1334 N/min) was applied at mid-span and the maximum sustained moment was calculated for each test. Two 69-in.-long (175.26 cm) prisms, each having different concrete release strength, were tested with each of the 5 wire types. These prisms were tested at both ends, with a different embedment length assessed at each end. Thus, for each wire type and concrete release strength evaluated, a total of 4 tests were conducted for a total of 60 tests (5 wire types x 3 release strengths x 4 tested embedment lengths). Test results indicate that the concrete compressive strength at de-tensioning can have a direct iMPact on the ultimate flexural capacity of the members, and this has significant design implications for pretensioned concrete railroad ties. Results are discussed and recommendations made. INTRODUCTION The first major utilization of prestressed concrete ties in North America was in 1966 (Hanna, 1979). The main tasks of railroad ties as an integral part of railroad track include preventing rails from any lateral or longitudinal displacements. Thus, the main function of railroad ties is stabilization of rails [1]. The use of prestressed concrete railroad ties is growing in the United States as the railroad industry is becoming more efficient. This growing is justified by many desirable features over wood crossties, including long life expectancy, environmental friendliness and reduction in fuel consumption of trains [2, 3]. Records to date show that pretensioned concrete crossties have brought more economical design and better structural behavior which improves the overall stability and performance of the railroad track [4]. In pretensioned concrete members, the total prestress force fully transfers to the surrounding concrete by the bond
SummaryNonhost resistance (NHR) is a robust plant immune response against non‐adapted pathogens. ... more SummaryNonhost resistance (NHR) is a robust plant immune response against non‐adapted pathogens. A number of nucleotide‐binding leucine‐rich repeat (NLR) proteins that recognize non‐adapted pathogens have been identified, although the underlying molecular mechanisms driving robustness of NHR are still unknown. Here, we screened 57 effectors of the potato late blight pathogen Phytophthora infestans in nonhost pepper (Capsicum annuum) to identify avirulence effector candidates. Selected effectors were tested against 436 genome‐wide cloned pepper NLRs, and we identified multiple functional NLRs that recognize P. infestans effectors and confer disease resistance in the Nicotiana benthamiana as a surrogate system. The identified NLRs were homologous to known NLRs derived from wild potatoes that recognize P. infestans effectors such as Avr2, Avrblb1, Avrblb2, and Avrvnt1. The identified CaRpi‐blb2 is a homologue of Rpi‐blb2, recognizes Avrblb2 family effectors, exhibits feature of lineage‐specifically evolved gene in microsynteny and phylogenetic analyses, and requires pepper‐specific NRC (NLR required for cell death)‐type helper NLR for proper function. Moreover, CaRpi‐blb2–mediated hypersensitive response and blight resistance were more tolerant to suppression by the PITG_15 278 than those mediated by Rpi‐blb2. Combined results indicate that pepper has stacked multiple NLRs recognizing effectors of non‐adapted P. infestans, and these NLRs could be more tolerant to pathogen‐mediated immune suppression than NLRs derived from the host plants. Our study suggests that NLRs derived from nonhost plants have potential as untapped resources to develop crops with durable resistance against fast‐evolving pathogens by stacking the network of nonhost NLRs into susceptible host plants.
Abstract Bacterial speck, caused by the pathogen Pseudomonas syringae pv. tomato, is one of the m... more Abstract Bacterial speck, caused by the pathogen Pseudomonas syringae pv. tomato, is one of the most common diseases in tomato production. Together with Pto kinase, the NLR (nucleotide-binding domain leucine-rich repeat containing) protein Prf confers resistance against the bacterial speck pathogen by recognizing AvrPto and AvrPtoB, two Type III effector proteins secreted by P. syringae pv. tomato. This Prf/Pto pathway is part of a complex NLR network in solanaceous plants that mediates resistance to diverse pathogens through the helper NLR proteins NRCs (NLR required for cell death). We previously showed that, in Nicotiana benthamiana, the hypersensitive cell death elicited by expression of AvrPto and Pto, which activate immunity through the endogenous Prf ortholog NbPrf, requires functionally redundant NRC2 and NRC3. However, whether tomato (Solanum lycopersicum) Prf (SlPrf) confers resistance to the bacterial speck pathogen through NRC2 and NRC3 has not been determined. In this study, we show that SlPrf requires NRC2 and NRC3 to trigger hypersensitive cell death and disease resistance in both N. benthamiana and tomato. We found that the hypersensitive cell death induced by AvrPtoB/Pto/SlPrf in N. benthamiana is compromised when NRC2 and NRC3 are silenced, indicating that SlPrf is an NRC2/3-dependent NLR. We validated this finding by showing that silencing NRC2 and NRC3 in the bacterial speck resistant tomato ‘Rio Grande 76R’ compromised Prf-mediated resistance. These results indicate that the NRC network extends beyond N. benthamiana to solanaceous crops.
ABSTRACT An experimental testing program was conducted at Kansas State University (KSU) to test t... more ABSTRACT An experimental testing program was conducted at Kansas State University (KSU) to test the bond characteristics of various 5.32 mm-diameter, Grade 270 low-relaxation steel wires used in prestressed concrete railroad ties. This un-tensioned pullout test could serve as a quality control test similar to the NASP (North American Strand Producers) Strand Bond Test that has been developed for pre-tensioned strands. A total of twelve (12) wires produced by six different steel manufacturers were used to develop the wire pullout test. All of the wires were tested in their " as-received " condition and have different indent geometries. It is generally accepted that indentations in the wire improve the bond between the steel and concrete. However, there are currently no commonly accepted quality control tests that accurately predict a wire's bond characteristics in a pre-tensioned application. The un-tensioned pullout test developed is comparable to the NASP [Strand] Bond Test. The specimens consist of a 4 in. (100 mm) outer-diameter tube with a total length of 8 in. (200 mm) and a steel plate welded to the bottom. The 5.32 mm-diameter wire was centered in the tube and the sand-cement mortar was placed and allowed to cure. The flow of the mortar was measured for consistency and 2 " x 2 " (50 mm x 50 mm) mortar cubes were used to determine the compressive strength of the mortar. The specimens were tested when the compressive strength of the mortar was between 4500 and 5000 psi (31.0 MPa and 34.5 MPa). Each batch of mortar contained 12 pullout specimens; one with each wire type. Each wire was tested six times leading to a total of six batches and a total of 72 mortar specimens. During testing, the wires were loaded in force control at the bottom, while continuously monitoring and recording the movement (slip) of the wire with respect to the mortar at the opposite (top) end. The force verses end-slip data of the six tests for each wire type were numerically combined to obtain the average bond performance. These average results from the un-tensioned pullout tests were then compared to transfer length measurements from accompanying pre-tensioned concrete prisms. In general, the wire end slip measurements from the pullout tests were found to have good correlation with the measured transfer length. For all 12 wires, a coefficient of determination (R 2) of 0.872 was found between the average pullout force (at 0.10-inch (2.54 mm) of wire free-end slip) and average transfer length measurements from the accompanying concrete prism tests. However, when only the indented wires were considered, the R 2 increased to 0.913.
At present, high dimensional global optimization problems with time-series models have received m... more At present, high dimensional global optimization problems with time-series models have received much attention from engineering fields. Bayesian optimization has quickly become a popular and promising approach for solving global optimization problems since it was proposed. However, the standard Bayesian optimization algorithm is insufficient to solving the global optimal solution when the model is high-dimensional. Hence, this paper presents a novel high dimensional Bayesian optimization algorithm by considering dimension reduction and different dimension fill-in strategies. Most existing literature about Bayesian optimization algorithms did not discuss the sampling strategies to optimize the acquisition function. This study proposed a new sampling method based on both the multiarmed bandit and random search methods while optimizing the acquisition function. Besides, based on the timedependent or dimension-dependent characteristics of the model, the proposed algorithm can reduce the dimension evenly. Then, five different dimension fill-in strategies were discussed and compared in this study. Finally, to increase the final accuracy of the optimal solution, the proposed algorithm adds a local search based on a series of Adam-based steps at the final stage. Our computational experiments demonstrated that the proposed Bayesian optimization algorithm could achieve reasonable solutions with excellent performances for high dimensional global optimization problems with a time-series optimal control model.
A comprehensive study was conducted to determine the variation in transfer length of pre-tensione... more A comprehensive study was conducted to determine the variation in transfer length of pre-tensioned prestressed concrete railroad ties with different parameters, including prestressing steel type and concrete variables. The in-depth evaluation included different prestressing reinforcement types that are employed in concrete railroad ties worldwide. The study consisted of two phases; Lab-Phase and Plant-Phase. Throughout the study, transfer lengths were determined from surface strain measurements of pre-tensioned concrete members. During the Lab-Phase, pre-tensioned concrete prisms were fabricated to replicate plant manufactured crossties. Different groups of prisms were fabricated during this phase, with each group used to determine the influence of selected prestressing steel or concrete variables on transfer length. A special jacking arrangement was employed to ensure that each of the reinforcements was tensioned to the same force. During the Lab-Phase, an 8-inch Whittemore gage was utilized to determine concrete surface displacements and thereby calculate surface strains. Later, during the Plant-Phase, pre-tensioned concrete railroad ties were fabricated at a concrete crosstie manufacturing plant with the same group of reinforcements. In-plant concrete surface strains were determined by utilizing both the Whittemore gage and two automated laserspeckle imaging (LSI) devices. Later, a long-term study was conducted on plant-manufactured crossties that were cast exclusively to utilize the mechanical (Whittemore) gage system. Various results from both the Lab-Phase and Plant-Phase are presented along with discussion. Potential benefits of laboratory prisms in estimating transfer lengths is also discussed. Results from both phases indicated that large variations in transfer lengths are due primarily to variations in the bond quality of the different prestressing tendons and the concrete strength at detensioning. Results pertaining to the variation in bond quality due to other concrete variables are also presented. A comprehensive study of prestressing steel and concrete variables affecting transfer length in pre-tensioned concrete crossties
Communications in Nonlinear Science and Numerical Simulation, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
This article presents two new mathematical models, an information forgetting curve (IFC) model an... more This article presents two new mathematical models, an information forgetting curve (IFC) model and a memory reception fading and cumulating (MRFC) model, to examine forgetting and learning behaviors of individuals during an infectious disease epidemic. Both models consider how epidemic prevalence and community behaviorchange information may affect agent emotions and subsequently influence an individual's behavior changes during an epidemic. The IFC model utilizes a forgetting curve to process epidemic information, and the MRFC model formulates disease information variations using the Itô diffusion process. Sensitivity analysis and simulation comparisons showed that the MRFC model more accurately describes the epidemic with high lethal rate gets high attention. The author also demonstrated that MRFC model has higher sensitivity parameters and is more flexible on wide ranges of infection rates than the IFC model. However, the IFC model is a better suited for widespread, low-risk mortality epidemics, such as seasonal influenza, the infection information and protective behavior have close relationships among the susceptible population. An agent-based simulation model also developed to mimic the epidemic prevalence of the 2009 Chicago H1N1 using public available historical data sets by IFC model.
International Journal of Modelling and Simulation, 2016
Patients who have sepsis are most likely to suffer from organ dysfunction. Organ dysfunction caus... more Patients who have sepsis are most likely to suffer from organ dysfunction. Organ dysfunction caused by sepsis results in high mortality rate and health care financial loss. The complexity of sepsis results in various dynamic patterns of sepsis for individual patients. Agent-based models provide a means to capture complex information in sepsis development by synthesizing concepts of sepsis progression to a model. Compared to a traditional mathematical modeling approach, agent-based models map interactions among agents to interactions among cells by embedding spatial effect, stochastic nature, and dynamics transitions, thereby demonstrating suitability for the development of complex biological processes. This article presents an integrated-mathematical-multi-agent-based model (IMMAB) to model and simulate acute inflammatory response (AIR), an initial stage of sepsis progression. To our knowledge, this IMMAB is the first version of an agent-based model that measures quantitative levels of indicators in sepsis progression by incorporating experimental data. Despite abstraction and generality, our simulated results reproduced dynamic patterns of AIR progression reported in existing experimental studies. Furthermore, our IMMAB captured diverged outcomes of individual patients when initial loads of pathogen are from 300 to 1000 numerical count. In the end, we inferred that Monocyte and IL-10 are possibly potential therapeutic targets in pre-clinic experiments.
This paper proposes a new, information-transmission-based behavior-switch that applies the indivi... more This paper proposes a new, information-transmission-based behavior-switch that applies the individual fear factor (IFF) to describe how information regarding current disease epidemics can cause human behavior change in a disease-dynamic system. This research is a first attempt to mathematically model how an individual's emotions influence behavior. The approach can be used to study the relationship of information dissemination (e.g., broadcasting, public health education, news media, etc.) and human behaviors during disease outbreaks. The expression of IFF and a mathematical IFF model that combines human behaviors with a classic SIR model is presented, and an optimal strategy that reduces the number of infected individuals and financial loss due to switch behaviors is proposed. In particular, model stability is analyzed and corresponding necessary conditions are determined. This novel modeling approach shows that information transmission influence individual fear, resulting in a variety of human behaviors and leading to numerous disease consequences.
Concrete railroad ties have been used in increasing numbers in the U.S., particularly in high-spe... more Concrete railroad ties have been used in increasing numbers in the U.S., particularly in high-speed rail, heavy-haul freight lines, and new track construction because of their reduced deflections, durability, and competitive cost. In-track assessment of concrete railroad ties can be a challenge, however because many exterior tie surfaces are covered by tie pads and rail or ballast. This damage may include concrete section wear from abrasion, cracking, or crumbling, or other types of defects. Damage internal to the concrete can also not be seen visually. The time and cost needed to inspect these tie surfaces means that it is not routinely performed. Non-destructive testing offers promise as a way to assess concrete tie integrity without having to remove ballast, however more information is needed to know how well non-destructive techniques work in detecting damage. Two of the most promising techniques for investigating the integrity of concrete non-destructively are ultrasonic pulse ...
During January 2013, concrete railroad ties were cast at a tie manufacturing plant with fifteen d... more During January 2013, concrete railroad ties were cast at a tie manufacturing plant with fifteen different reinforcement types that are widely employed in manufacturing of railroad ties worldwide. Among these reinforcements; there were 12 different 5.32 mm diameter wires with various surface indent geometries, two different 7-wire strands with 3/8-inch diameter, and one 3-wire strand with 5/16-inch diameter. Four concrete ties were cast for each reinforcement type for a total of 60 concrete ties. Among the four ties for each reinforcement type, two ties were installed in track and subjected to a cumulative in-track loading of 85 million gross tons (MGT). Before being subjected to this loading, special surface preparation was done on the ties to protect the strain measuring points on the bottom surface of the ties from surface abrasion during loading. The other two ties, which are companion ties for each reinforcement type, were not subjected to any loading. Surface strains of concret...
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Papers by Chih-Hang Wu