Physiological And Biochemical Significance Of Peanut (arachis Hypogaea L) Peroxidases In Growth

The molecular structures of peanut peroxidases from the cell suspension culture medium have been well characterized. The aim of present work is to investigate some of the physiological roles of these peroxidases, namely the functions in growth.;Specific polyclonal antibodies against both anionic and cationic peroxidases were produced by affinity chromatography. Immunological assays showed virtually no cross-reactivity between these antibodies and other compounds. The peroxidases from peanut cell suspension culture medium had {dollar}\u3e{dollar}80% immunological homologies with those from cultured cells and hypocotyls as determined by Ouchterlony gel diffusion, western blot and competitive ELISA. Based on these homologies both the purified peroxidases from the medium and the antibodies against them were used for the study of the physiological functions of peroxidases in cultured cells and hypocotyls.;An increase of peroxidase quantity and activity in the hypocotyl segments was correlated with the inhibition of growth by meta-fluoro-tyrosine (MFT) added to the culture medium. A further linkage between growth and peroxidases has been clarified through the enhancement of growth by antibodies and the inhibition of growth by peroxidases.;MFT reduced the synthesis of cationic peroxidase less than that of total proteins. On the other hand, the half live of cationic peroxidase was increased by MFT. These two effects are assumed to be the cause of the increase of cationic peroxidase quantity and activity in the tissues treated with MFT. It was also determined that the synthesis and the degradation of peroxidases were regulated at transcriptional and translational levels.;Possible biochemical mechanisms for the regulatory role of peroxidases in growth were investigated. Peroxidases catalyzed the in vivo and in vitro oxidative couplings of cell wall polymer-linked tyrosine, ferulic acid and coniferyl alcohol. In this way, peroxidases mediate the crosslinkings of extensins and polysaccharides in the cell wall, and thus control the rheology and elongation of the cell wall. By using isolated cell walls and specific antibodies it was indicated that the cationic peroxidase played a major role for in vivo couplings. No difference in the affinity of anionic and cationic peroxidases for the phenol substrates was revealed by enzyme kinetic studies. Peroxidases were found to mediate the metabolism of IAA and ascorbate, which regulates growth. The anionic peroxidase had a higher affinity for IAA and ascorbate as well as a higher Vmax in the peroxidation of IAA and ascorbate.;The cell wall-association of most cationic isozyme and the cytoplasm-association of most anionic isozyme were visualized by immunogold labelling. This is consistent with the dominant role of the cationic isozyme in the elongation of the cell wall, and with the principal action of anionic isozyme in the cytoplasm-located IAA and ascorbic acid peroxidation

Experimental study of hybrid strengthening technique using carbon fiber laminates and steel plates for reinforced concrete slabs

External bonding (EB) technique has been used widely to strengthen reinforced concrete (RC) structures in civil engineering over several decades. Steel and fiber reinforced polymers (FRP) are the two most common materials used for strengthening RC structures. Although each material has its advantages for EB application, they also have their own weaknesses. Steel plates are heavy and poor in corrosion resistance, and the thickness of steel plates is also limited due to lack of shape flexibility for strengthening RC structures. The EB-FRP technique is restricted for broader applications because the bond interface is the weakest link in such retrofitted or strengthened concrete members, resulting in sudden and brittle debonding failure, and the strength of FRP has not been fully utilized. To overcome these weaknesses, an innovative strengthening method combining FRP and steel materials was explored in this research. Carbon fiber laminates (CFL) and thin steel plates (SP) were combined in different ways to determine the most effective hybrid strengthening configuration. A total of nineteen RC slabs strengthened by different configurations were tested under four-point bending. Failure modes, load versus deflection curves, strains of internal reinforcement bars, CFL and SP, and stiffness of the strengthened specimens were analyzed. The test results proved that the CFL-SP hybrid strengthening technique was effective. The average maximum increases in flexural capacity and stiffness were 204.2% and 91% over the control slab, respectively. In addition, the cracking and steel yielding loads of slabs strengthened with CFL-SP composite material were higher than those of slabs strengthened by FRP or steel plate only. By combining with steel plate, FRP material was used more efficiently and the stiffness of the strengthened RC slabs was improved. The overlap-type hybrid configuration of bonding CFL as inner plates while steel as outer plates was proved as the most effective hybrid strengthening method within all configurations tested in this research

Efficient Estimation of General Treatment Effects using Neural Networks with A Diverging Number of Confounders

The estimation of causal effects is a primary goal of behavioral, social, economic and biomedical sciences. Under the unconfounded treatment assignment condition, adjustment for confounders requires estimating the nuisance functions relating outcome and/or treatment to confounders. The conventional approaches rely on either a parametric or a nonparametric modeling strategy to approximate the nuisance functions. Parametric methods can introduce serious bias into casual effect estimation due to possible mis-specification, while nonparametric estimation suffers from the "curse of dimensionality". This paper proposes a new unified approach for efficient estimation of treatment effects using feedforward artificial neural networks when the number of covariates is allowed to increase with the sample size. We consider a general optimization framework that includes the average, quantile and asymmetric least squares treatment effects as special cases. Under this unified setup, we develop a generalized optimization estimator for the treatment effect with the nuisance function estimated by neural networks. We further establish the consistency and asymptotic normality of the proposed estimator and show that it attains the semiparametric efficiency bound. The proposed methods are illustrated via simulation studies and a real data application

Experimental study of the Couple Characteristics of the Refrigerants and Vortex Tube

Vortex tube is a simple energy separation device, also known as Ranque tube or Hilsch tube, which can separate a high-pressure stream into two different hot and cold streams. Since its simple structure and unique temperature separation characteristics, vortex tube has been widely used in various industries. In recent years, with the in-depth study of the vortex tube, it has been found that compared with the conventional expansion expander and the throttle valve, the vortex tube is much more structurally simple and efficient, respectively. Researchers have proposed the use of the vortex tube in the refrigeration system in order to reduce the throttling loss and improve system efficiency. This has important implications for improving the performance of the system, to achieve energy saving and emission reduction. However, due to the different physical properties of the different working fluid, energy separation in the vortex tube are not the same. In the existing studies on the vortex tube, the working fluid mainly used air, nitrogen, carbon dioxide and other natural refrigerants, the research about the influence of refrigerants is few. Due to the fact that the vortex tube is increasingly used in refrigeration and heating system, it is urgent to study the coupling characteristics between vortex tube and refrigerants and find optimal conditions in different systems. The different temperature separation effect of the refrigerants in the vortex tube in the low inlet pressure(300kPa) have been studied in our previous study and three fluid characteristics (specific heat ratio, kinematic viscosity, thermal conductivity) were considered as main influencing factors of energy separation. The influence of different working fluid in high pressure conditions has not been considered ,which is part of research work in this paper. The coupling characteristic between vortex tube and refrigerants wais studied and the closed loop system was constructed. R134a, R744, R32, R227ea were selected as the working fluids, experiments were carried out in different inlet pressure(500kPa?850kPa), different inlet temperature (308.15K?333.15K), different cold flow ratio (20%?97%). The temperature separation of different working fluids under different conditions were explored and the influences of different characteristics of the working fluids on the temperature separation process were discussed. These studies can help more profound understanding of the vortex tube temperature separation process, and also has certain significance on the applications of the vortex tube in the refrigeration system