Heat tolerance studies for wheat improvement

Talukder, Shyamal Krishna Kansas State University 2013 해외박사(DDOD)

Heat stress is one of the major environmental constraints for wheat production worldwide. High temperature during grain filling in wheat leads to a significant reduction in yield. In this research, three different projects were completed. The first project was to study cytoplasmic effects on heat tolerance in wheat, where ten different alloplasmic lines of wheat were backcrossed with four different wheat varieties: 'Karl 92', 'Ventnor', 'U1275' and 'Jagger'. The nuclear genome of the alloplasmic lines was substituted by backcrossing six times using the recurrent parents as males. During the fifth and/or fourth backcross, reciprocal crosses were made to develop NILs (Near Isogenic Lines) for cytoplasm. Sixty-eight NILs and their parents were evaluated in growth chambers for post-anthesis heat tolerance. Plants were grown in the greenhouse and placed under heat stress for 14 days starting at 10 days after anthesis. Growth chambers were maintained at 35°/30°C for heat stress and the greenhouse was maintained at 20°/15°C as the optimum temperature. Effects of high temperature on chlorophyll content and Fv/F m (a chlorophyll fluorescence measuring parameter) were found to be significant. Cytoplasms 1, 4, 5, 8, 9 and10 provided greater tolerance in one or more nuclear backgrounds. These results indicated that cytoplasmic effects can contribute to heat tolerance of wheat. The second project focused on identification of quantitative trait loci (QTL) for thylakoid membrane damage (TMD), SPAD chlorophyll content (SCC) and plasma membrane damage (PMD), as these traits are found to be associated with resistance to heat stress and contributes to relatively stable yield under high temperature. A RIL (Recombinant Inbred line) population of a cross between winter wheat cultivars 'Ventnor' and 'Karl 92' was evaluated using two different temperature regimes (20°/15°C, 36°/30°C) imposed at ten days after anthesis. The aforementioned traits were evaluated and associated with various molecular markers (SSR, AFLP and SNP). The putative QTL associated are localized on chromosomes 6A, 7A, 1B, 2B and 1D and have the potential to be used in marker assisted selection for improving heat tolerance in wheat. In the third project, a transgenic approach to increase grain fill during high temperatures was investigated. Grain fill is reduced at temperatures above 25°C in wheat partly due to the inactivity of soluble starch synthase. We isolated a soluble starch synthase gene from rice that has the potential to overcome this deficiency during high temperatures and placed it behind both a constitutive promoter and an endosperm-specific promoter. Transgene expression and the effects of the transgene expression on grain yield-related traits for four generations (T0, T 1, T2 and T3) were monitored. The results demonstrated that even after four generations, the transgene was still expressed at high levels, and transgenic plants produced grains of greater seed weight than Bobwhite control plants under the same environmental conditions. Thousand-seed weight under high temperatures increased 21-34% in T2 and T3 transgenic plants when compared to the non-transgenic control plants. In addition, the duration of photosynthesis was longer in transgenic wheat than in non-transgenic controls. Our study demonstrated that expression of rice soluble starch synthase gene in wheat can improve wheat yield under heat stress conditions.

Laminar flame speeds for n-butanol and methyl decanoate at elevated pressures and temperature

Talukder, Niladri GRADUATE SCHOOL, ANDONG NATIONAL UNIVERSITY 2017 국내석사

Experimental investigations of n-butanol-air and methyl decanoate-air premixed flames have been performed to obtain laminar flame speeds at elevated pressures and temperature for a wide range of equivalence ratios. Shadowgraph technique has been applied to facilitate optical access to the combustion chamber and high-speed camera system has been used to collect images of the flame front propagation for the spherically outward propagating flames, initiated at the center of the chamber. MATLAB image processing code has been used to process data from the images and calculate flame speeds. Similar data trend has been observed for laminar flame speeds against equivalence ratios like other conventional hydrocarbon-air premixed flames. Flame speeds gradually raised from the fuel-lean conditions to the stoichiometric condition. Peaking the value at slightly fuel-rich condition (around φ= 1.1) it gradually went down as the mixtures were made fuel-rich. Like other conventional hydrocarbons, these premixed laminar flame speeds are found to be decreased with the elevation of initial pressures for specific condition.

Applications of parametric and semi-parametric models for longitudinal data analysis

Talukder, Hisham University of Maryland, College Park 2014 해외박사(DDOD)

A wide range of scientific applications involve analyses of longitudinal data. Whether it is time or location, careful considerations need to be made when applying different statistical tools. One such challenge is to correctly estimate variance components in observed data. In this dissertation, I apply statistical tools to solve problems involving longitudinal data in the field of Biology, Healthcare and Networks. In the second chapter, I apply SSANOVA models to find regions in the genome that have a specific biological trait. We introduce a direct approach of estimating genomic longitudinal data of two different biological groups. Using SSANOVA we then produce a novel method to estimate the difference between the two groups and find regions (location or time) where this difference is biologically significant. In the third chapter, we analyze longitudinal network data using an overdispersed Poisson model. We build a network of musical writers yearly for a 42 year period. Using statistical models, we predict network level topology changes and find covariates that explain these changes. Network level characteristics used for this chapter include average node degree, clustering coefficient and network density. We also build a visualization tool using R-Shiny. The fourth chapter uses data partitioning to study the difference between insured patients and uninsured patients in health outcomes. There is a disparity in health outcomes depending on an individual's type of insurance. The level of risk for an injury is the longitudinal aspect of this dataset. We partition the data into four pre-defined risk categories and evaluate the disparity between insured and uninsured patients using logistic regression models.

Parallel subgraph mining on hybrid platforms: HPC systems, multi-cores and GPUs

Talukder, Nilothpal Rensselaer Polytechnic Institute 2016 해외박사(DDOD)

Frequent subgraph mining (FSM) is an important problem in numerous application areas, such as computational chemistry, bioinformatics, social networks, computer programming languages, etc. However, the problem is computationally hard because it requires enumerating possibly an exponential number of candidate subgraph patterns, and checking their presence in a single large graph or a database of graphs. In recent years, it has become more challenging due to the rapidly increasing graph sizes. For instance, the number of users on online social networks like Facebook are now in billions. In this thesis, we present novel algorithms to scale frequent subgraph mining on a variety of computing platforms/architectures. These include High Performance Computing systems (HPC), such as IBM Blue Gene/Q, multi-core CPUs, and Graphics Processing Units (GPUs). First, we present frequent subgraph mining from a single, very large, labeled network. Our approach is the first distributed method to mine a massive input graph that is too large to fit in the memory of any individual compute node. The input graph thus has to be partitioned among the nodes, which can lead to potential false negatives. Furthermore, for scalable performance it is crucial to minimize the communication among the compute nodes. Our algorithm, DistGraph, ensures that there are no false negatives, and uses a set of optimizations and efficient collective communication operations to minimize information exchange. To our knowledge, DistG raph is the first approach demonstrated to scale to graphs with over a billion vertices and edges. Scalability results on up to 2048 IBM Blue Gene/Q compute nodes, with 16 cores each, show very good speedup. The results also show orders of magnitude speedup compared with the state-of-art sequential solutions. Then, we describe a hybrid parallel approach ParG raph to mine a single moderate sized graph that fits inside the memory of a single compute node. However, this approach uses a hybrid load balancing scheme to efficiently distribute workload on both MPI and thread levels. Moreover, unlike the distributed approach it does not require synchronization among processes at each expansion level of the growing patterns, which makes it very efficient. Finally, we describe parallel frequent subgraph mining on a database of multiple labeled graphs, using Graphics Processing Units (GPUs). In recent times, GPUs have emerged as a relatively cheap but powerful architecture for general purpose computing. However, the thread-model for GPUs is different from that of CPUs, which makes the parallelization of graph mining algorithms on GPUs a challenging task. We investigate the major challenges for GPU-based graph mining, and perform extensive experiments on several real-world and synthetic datasets, achieving speedups up to 9 over a sequential algorithm running on a single-core CPU.

Allosteric effects of calcium and voltage on the gating of a calcium sensitive potassium channel

Talukder, Gargi Stanford University 2001 해외박사(DDOD)

The cloned potassium channel <italic>mSlo</italic> is sensitive to intracellular calcium as well as to changes in membrane voltage. In this dissertation, I have examined the effects of both calcium and voltage on the gating of single molecules of <italic>mSlo</italic> heterologously expressed in <italic>Xenopus laevis</italic> oocytes. Using the inside out voltage clamp recording technique, I have examined the single channel kinetics of <italic>mSlo</italic> to determine the complexity of its gating in the absence of any intracelluar calcium. I have found that the intrinsic voltage dependence of <italic>mSlo</italic> is quite complex, and that even in the absence of calcium the channel is able to occupy multiple closed and open conformational states. I extended this study of channel gating in zero calcium by examining gating behavior in single channels composed of subunits with non-identical voltage sensors. I was able to form these heteromeric channels by coexpressing wildtype <italic>mSlo</italic> channels with the R207Q point mutant. This point mutation neutralizes a residue in the S4 transmembrane region of the subunit, and its result on gating is to shift the equilibrium of voltage sensor activation toward negative voltages. By examining the behavior of channels composed of both wildtype and R207Q subunits, I was able to test the possibility of cooperative interactions between voltage sensors in this channel. My results indicate that the voltage sensors of <italic>mSlo</italic> do not show a strong evidence of cooperativity during channel gating. Similarly, I investigated the possibility of cooperative interactions between the calcium sensors of <italic>mSlo</italic> by studying the gating of single molecules of <italic>mSlo</italic> with non-identical calcium sensors. I formed these heteromers by coexpressing wildtype subunits with chimeric subunits. The chimeric subunits were formed from the core of <italic>mSlo1 </italic> and the C-terminus of <italic>mSlo3</italic>, a large conductance potassium channel that is voltage dependent but shows no sensitivity to changes in intracellular calcium. My results with these calcium sensor heteromultimers show that the calcium sensors of <italic>mSlo</italic> also act independently during channel gating.

Nonlinear feature extraction for pattern recognition applications

Talukder, Ashit Carnegie-Mellon University 1999 해외박사(DDOD)

We discuss a new nonlinear feature extraction algorithm, the solution of which can be obtained in closed-form. The features can be used for general pattern recognition applications including those involving class representation, class discrimination, or for both simultaneously. The feature extraction method is called the maximum representation and discrimination feature (MRDF) method. A new discrimination measure is used that can handle classes with multiple clusters in the input space. A computationally efficient nonlinear MRDF procedure to extract nonlinear features from high-dimensional input images is devised. This nonlinear feature extraction procedure is shown to provide very general nonlinear surfaces, in contrast with other nonlinear techniques. The nonlinear MRDF is also shown to generalize to well-known linear and nonlinear image processing operations. We show the use of the MRDF feature extraction technique for classification of product inspection items, classification and pose estimation of objects (machined-parts), and pose-invariant face recognition. Comparisons of the results obtained with our MRDF features with other well-known feature extraction procedures such as the Karhunen-Loeve (KL) transform, and the Fisher linear discriminant are also made.

Paletteviz: A Method for Visualization of High-Dimensional Pareto-Optimal Front and Its Applications to Multi-Criteria Decision Making and Analysis

Talukder, Akm. Khaled Ahsan Michigan State University ProQuest Dissertations & 2022 해외박사(DDOD)

Visual representation of a many-objective Pareto-optimal front in four or more dimensional objective space requires a large number of data points. Moreover, choosing a single point from a large set even with certain preference information is problematic, as it imposes a large cognitive burden on the decision-makers. Therefore, many-objective optimization and decision-making practitioners have been interested in effective visualization methods to en- able them to filter down a large set to a few critical points for further analysis. Most existing visualization methods are borrowed from other data analytics domains and they are too generic to be effective for many-criterion decision making. In this dissertation, we propose a visualization method, using star-coordinate and radial visualization plots, for effectively visualizing many-objective trade-off solutions. The proposed method respects some basic topological, geometric and functional decision-making properties of high-dimensional trade- off points mapped to a three-dimensional space. We call this method Palette Visualization (PaletteViz). We demonstrate the use of PaletteViz on a number of large-dimensional multi- objective optimization test problems and three real-world multi-objective problems, where one of them has 10 objective and 16 constraint functions. We also show the uses of NIM-BUS and Pareto-Race concepts from canonical multi-criterion decision making and analysis literature and introduce them into PaletteViz to demonstrate the ease and advantage of the proposed method.

WO3 히터가 있는 새로운 3 극 마이크로 퓨즈

Talukder Shovon 울산대학교 대학원 2022 국내석사

Portable electronic devices are comprised of a secondary battery or DC charge source and due to abrupt micro-current alteration and short circuit overcurrent; fire and explosions can happen. A protecting device should steadily cater to phenomena like overcurrent situation and micro-current alter state to avoid any hazardous circumstances. In this work, high current protecting multi-layered thin film triode micro fuses are designed and simulated using the MEMS-based tool of COMSOL Multiphysics software and then the device has been fabricated using the RF magnetron sputtering method and then electrically analyzed to compare between simulation and experimental data. To design a low melting point-based alloy for fuse element and negative temperature coefficient (NTC) based metal oxide functions as a heater material and to control high current high power is the primary purpose of this investigation. A Lead-tin (90Pb:10Sn) alloy has been employed as the low melting point-based fuse element and tungsten oxide (WO3) is integrated with the layer as a self-heating resistor material. The electro-thermo-mechanical behavior is assessed, and a three-dimensional time-dependent modelling and simulation technique has been performed in both steady state and transient conditions with varying some physical and electrical parameters. The triode fuse simulated data shows that around 5.6A current the device temperature reaches to nearly 300°C and thus the triode fuse works by blowing the fuse. More importantly, after fabricating the device experimentally using nanofabrication technique, electrical characterization has been performed and experimental data almost provides similar result. The triode micro fuse device let current flow until 5A current, and the temperature distribution of the device follows simulated phenomena, thus blows at 5A current. This device completely suited for portable secondary battery protection system where current rating islike this device’s rated current. This advanced research will facilitate a new class of portable micro fuse to be assembled with triode mechanisms in real-time technology for self-control protector.