26 research outputs found
Cloning and functional characterization of a novel mitochondrial N-ethylmaleimide-sensitive glycerol-3-phosphate acyltransferase (GPAT2)
Glycerol-3-phosphate acyltransferase (GPAT) catalyzes the initial and rate-limiting step in glycerolipid synthesis. Several mammalian GPAT activities have been recognized, including N-ethylmaleimide (NEM)-sensitive isoforms in microsomes and mitochondria and an NEM-resistant form in mitochondrial outer membrane (GPAT1). We have now cloned a second mitochondrial isoform, GPAT2 from mouse testis. The open reading frame encodes a protein of 798 amino acids with a calculated mass of 88.8 kDa and 27% amino acid identity to GPAT1. Testis mRNA expression was 50-fold higher than in liver or brown adipose tissue, but the specific activity of NEM-sensitive GPAT in testis mitochondria was similar to that in liver. When Cos-7 cells were transiently transfected with GPAT2, NEM-sensitive GPAT activity increased 30%. Confocal microscopy confirmed a mitochondrial location. Incubation of GPAT2-transfected Cos-7 cells with trace (3 ÎŒM; 0.25ÎŒCi) [1-14C]oleate for 6 h increased incorporation of [14C]oleate into TAG 84%. In contrast, incorporation into phospholipid species was lower than in control cells. Although a polyclonal antibody raised against full-length GPAT1 detected an âŒ89 kDa band in liver and testis from GPAT1 null mice and both 89 and 80 kDa bands in BAT from the knockout animals, the GPAT2 protein expressed in Cos-7 cells was only 80 kDa. In vitro translation showed a single product of 89 kDa. Unlike GPAT1, GPAT2 mRNA abundance in liver was not altered by fasting or refeeding. GPAT2 is likely to have a specialized function in testis
Generation of ESTs for Flowering Gene Discovery and SSR Marker Development in Upland Cotton
BACKGROUND: Upland cotton, Gossypium hirsutum L., is one of the world's most important economic crops. In the absence of the entire genomic sequence, a large number of expressed sequence tag (EST) resources of upland cotton have been generated and used in several studies. However, information about the flower development of this species is rare. METHODOLOGY/PRINCIPAL FINDINGS: To clarify the molecular mechanism of flower development in upland cotton, 22,915 high-quality ESTs were generated and assembled into 14,373 unique sequences consisting of 4,563 contigs and 9,810 singletons from a normalized and full-length cDNA library constructed from pooled RNA isolated from shoot apexes, squares, and flowers. Comparative analysis indicated that 5,352 unique sequences had no high-degree matches to the cotton public database. Functional annotation showed that several upland cotton homologs with flowering-related genes were identified in our library. The majority of these genes were specifically expressed in flowering-related tissues. Three GhSEP (G. hirsutum L. SEPALLATA) genes determining floral organ development were cloned, and quantitative real-time PCR (qRT-PCR) revealed that these genes were expressed preferentially in squares or flowers. Furthermore, 670 new putative microsatellites with flanking sequences sufficient for primer design were identified from the 645 unigenes. Twenty-five EST-simple sequence repeats were randomly selected for validation and transferability testing in 17 Gossypium species. Of these, 23 were identified as true-to-type simple sequence repeat loci and were highly transferable among Gossypium species. CONCLUSIONS/SIGNIFICANCE: A high-quality, normalized, full-length cDNA library with a total of 14,373 unique ESTs was generated to provide sequence information for gene discovery and marker development related to upland cotton flower development. These EST resources form a valuable foundation for gene expression profiling analysis, functional analysis of newly discovered genes, genetic linkage, and quantitative trait loci analysis
Multi-objective optimization and uncertainty quantification for inductors based on neural network
Purpose: The prolonged training time of the neural network (NN) has sparked considerable debate regarding their application in the field of optimization. The purpose of this article is to explore the beneficial assistance of neural network (NN)-based alternative models in inductance design, with a particular focus on multi-objective optimization and uncertainty analysis processes.Design/methodology/approach: Under Gaussian-distributed manufacturing errors, we predict error intervals for Pareto points and select robust solutions with minimal error margins. Furthermore, we establish correlations between manufacturing errors and inductance value discrepancies, offering a practical means of determining permissible manufacturing errors tailored to varying accuracy requirementsFindings: The NN-assisted methods are demonstrated to offer a substantial time advantage in multi-objective optimization compared to conventional approaches, particularly in scenarios where the trained neural network is repeatedly utilized. Also, NN models allow for extensive data-driven uncertainty quantification, which is challenging for traditional methodsOriginality: Three objectives including saturation current are considered in the multi-optimization, and the time advantages of the NN are thoroughly discussed by comparing scenarios involving single optimization, multiple optimizations, bi-objective optimization, and tri-objective optimization. We propose direct error interval prediction on the Pareto front, utilizing extensive data to predict the response of the Pareto front to random errors following a Gaussian distribution. This approach circumvents the compromises inherent in constrained robust optimization for inductance design and allows for a direct assessment of robustness that can be applied to account for manufacturing errors with complex distribution
A Continuous Characterization of Triebel-Lizorkin Spaces Associated with Hermite Expansions
We study the properties of the Triebel-Lizorkin spaces associated with the multidimensional Hermite expansions on Rd (dâ„1). In addition to the endpoint estimates, we give the continuous characterizations of these spaces via harmonic and thermic extensions from Rd into R+d+1. Based on this result, we obtain the boundedness of Riesz transform associated with the Hermite expansions
Weighted Multilinear Hardy Operators on Herz Type Spaces
This paper focuses on the bounds of weighted multilinear Hardy operators on the product Herz spaces and the product Morrey-Herz spaces, respectively. We present a sufficient condition on the weight function that guarantees weighted multilinear Hardy operators to be bounded on the product Herz spaces. And the condition is necessary under certain assumptions. Finally, we extend the obtained results to the product Morrey-Herz spaces
Optimization of Speed Profile with RTA Constraints under Wind Uncertainty
Four-dimensional (4D) trajectory is considered to be one of the effective means to reduce the environmental impact of aviation while increasing capacity and safety. This paper proposes an approach to optimize cruise speed profile subject to wind uncertainty, aiming to reduce the fuel burn complying with the Required Time of Arrival (RTA) constraints. The approach is based on a probabilistic framework, and the uncertainty propagation is analyzed using a Probability Transformation Method, and the probability distributions of arrival time and fuel consumption are determined. In addition, from an airborne operation perspective, transition profiles need to be considered in the reference speed optimization problem, aiming to improve the rationale of the reference trajectory. Numerical simulations are presented, and the results demonstrate that the speed profiles optimized by this method are able to meet the RTA constraints in the presence of wind uncertainty, with an average reduction of 7.04% in fuel consumption compared with that of the flight data
Stabilization Control of Underactuated Spring-Coupled Three-Link Horizontal Manipulator Based on Energy Absorption Idea
A spring-coupled three-link horizontal manipulator (STHM) is an underactuated mechanical system that possesses two control inputs and three degrees of freedom (DOF). This paper discusses the stabilization control problem for this multi-DOF underactuated system. By using an energy-absorbing idea, we design two types of virtual friction controllers: PsD controller and PD controller. Additionally, the stability of the control system is analyzed based on Lyapunov theory and LaSalleâs invariance principle. The design of the stabilizing controller in this paper makes good use of the physical characteristics of the STHM system. The design process of the whole control system is simple. Numerical examples demonstrate the validity and superiority of our developed control strategy
Stabilization Control of Underactuated Spring-Coupled Three-Link Horizontal Manipulator Based on Energy Absorption Idea
A spring-coupled three-link horizontal manipulator (STHM) is an underactuated mechanical system that possesses two control inputs and three degrees of freedom (DOF). This paper discusses the stabilization control problem for this multi-DOF underactuated system. By using an energy-absorbing idea, we design two types of virtual friction controllers: PsD controller and PD controller. Additionally, the stability of the control system is analyzed based on Lyapunov theory and LaSalle’s invariance principle. The design of the stabilizing controller in this paper makes good use of the physical characteristics of the STHM system. The design process of the whole control system is simple. Numerical examples demonstrate the validity and superiority of our developed control strategy
Nonlinear Global Stabilization Control for the Underactuated WAcrobot System
A WAcrobot is an underactuated nonlinear system that has three degrees of freedom (DOF) and two inputs. This paper discusses the global stabilization control problem for this 3-DOF underactuated system. A new control strategy is developed to solve this problem. The strategy first changes the 3-DOF WAcrobot system to be a 2-DOF reduced-order model in finite time. This transforms the stabilizing control of the WAcrobot system into that of the reduced-order model. After that, nonsingular control laws that globally stabilize the reduced-order model at the origin are designed. It guarantees the stabilizing control objective of the WAcrobot to be achieved. Finally, a simulation experimental example demonstrates the validity of the presented theoretical results. Simulation results show the advantage of our strategy over others