The role of a translation initiation factor subunit, elF3h, in Arabidopsis shoot apical meristem maintenance and auxin response

The objective of this study was to dissect the function of the h subunit of translation initiation factor 3, eIF3h, in Arabidopsis shoot apical meristem (SAM) maintenance and auxin response. Translational regulation has been proposed to play important roles in plant development and environmental stress responses. eIF3, with 12-13 protein subunits the largest of the initiation factor complexes, is involved in many essential steps in translation initiation, but little is known about the structural and functional roles of most eIF3 subunits in any organism. Using various techniques, such as scanning electron microscopy and confocal microscopy, I revealed defects in the eif3h mutant that included an enlarged SAM and a pin-formed shoot and a variety of defects in leaf initiation and morphogenesis.Many groups of genes, such as those encoding auxin response factors (ARFs) and stem cell regulators (CLAVATA1 and 3) were identified to have multiple upstream open reading frames (uORFs), which are generally inhibitory for the translation of downstream open reading frames and involved in translational control. Optimized translation assays indicated that ARFs and CLAVATA (CLV1, 3) genes were significantly less translated in the eif3h mutant, and removal of uORFs from CLV1 and CLV3 leaders significantly reduced their eIF3h dependence. Furthermore, the eif3h growth defects can be partially complemented by expressing the CLAVATA3 gene in its native domain. These results indicated that, eIF3h is involved in efficient translation of ARFs and CLV1, 3 genes by overcoming the translation repression by uORFs. The functional characterization of eIF3h provided the first evidence that translational control by eIF3h plays important roles in auxin signaling and shoot apical meristem maintenance.As part of this project I explored the utility of a viral sequence element described as an internal ribosome entry site. Even though no robust IRES activity could be confirmed under the experimental conditions used here, the sequence had substantial promoter activity. Because the promoter activity was de factor eIF3h independent, the sequence could be utilized a component of a new generation of translational reporter genes

The role of a translation initiation factor subunit, elF3h, in Arabidopsis shoot apical meristem maintenance and auxin response

The objective of this study was to dissect the function of the h subunit of translation initiation factor 3, eIF3h, in Arabidopsis shoot apical meristem (SAM) maintenance and auxin response. Translational regulation has been proposed to play important roles in plant development and environmental stress responses. eIF3, with 12-13 protein subunits the largest of the initiation factor complexes, is involved in many essential steps in translation initiation, but little is known about the structural and functional roles of most eIF3 subunits in any organism. Using various techniques, such as scanning electron microscopy and confocal microscopy, I revealed defects in the eif3h mutant that included an enlarged SAM and a pin-formed shoot and a variety of defects in leaf initiation and morphogenesis.Many groups of genes, such as those encoding auxin response factors (ARFs) and stem cell regulators (CLAVATA1 and 3) were identified to have multiple upstream open reading frames (uORFs), which are generally inhibitory for the translation of downstream open reading frames and involved in translational control. Optimized translation assays indicated that ARFs and CLAVATA (CLV1, 3) genes were significantly less translated in the eif3h mutant, and removal of uORFs from CLV1 and CLV3 leaders significantly reduced their eIF3h dependence. Furthermore, the eif3h growth defects can be partially complemented by expressing the CLAVATA3 gene in its native domain. These results indicated that, eIF3h is involved in efficient translation of ARFs and CLV1, 3 genes by overcoming the translation repression by uORFs. The functional characterization of eIF3h provided the first evidence that translational control by eIF3h plays important roles in auxin signaling and shoot apical meristem maintenance.As part of this project I explored the utility of a viral sequence element described as an internal ribosome entry site. Even though no robust IRES activity could be confirmed under the experimental conditions used here, the sequence had substantial promoter activity. Because the promoter activity was de factor eIF3h independent, the sequence could be utilized a component of a new generation of translational reporter genes

Global strong solutions to the compressible Navier-Stokes system with potential temperature transport

We study the global strong solutions to the compressible Navier-Stokes system with potential temperature transport in $\mathbb{R}^n.$ Different from the Navier-Stokes-Fourier system, the pressure is a nonlinear function of the density and the potential temperature, we can not exploit the special quasi-diagonalization structure of this system to capture any dissipation of the density. Some new idea and delicate analysis involved in high or low frequency decomposition in the Besov spaces have to be made to close the energy estimates.Comment: 12page

Translation reinitiation and development are compromised in similar ways by mutations in translation initiation factor eIF3h and the ribosomal protein RPL24

Background Within the scanning model of translation initiation, reinitiation is a non-canonical mechanism that operates on mRNAs harboring upstream open reading frames. The h subunit of eukaryotic initiation factor 3 (eIF3) boosts translation reinitiation on the uORF-containing mRNA coding for the Arabidopsis bZip transcription factor, AtbZip11, among others. The RPL24B protein of the large ribosomal subunit, which is encoded by SHORT VALVE1, likewise fosters translation of uORF-containing mRNAs, for example mRNAs for auxin response transcription factors (ARFs). Results Here we tested the hypothesis that RPL24B and eIF3h affect translation reinitiation in a similar fashion. First, like eif3h mutants, rpl24b mutants under-translate the AtbZip11 mRNA, and the detailed spectrum of translational defects in rpl24b is remarkably similar to that of eif3h. Second, eif3h mutants display defects in auxin mediated organogenesis and gene expression, similar to rpl24b. Like AtbZip11, the uORF-containing ARF mRNAs are indeed undertranslated in eif3h mutant seedlings. Conclusion We conclude that, similar to eIF3h, RPL24B bolsters the reinitiation competence of uORF-translating ribosomes. Coordination between eIF3 and the large ribosomal subunit helps to fine-tune translation of uORF-containing mRNAs and, in turn, to orchestrate plant development. doi:10.1186/1471-2229-10-19

Investigation on hydrodynamic characteristics of a hydrofoil based on γ-Re_θttransition model

The complex flow field caused by the dynamic stall can affect the operational stability of hydrodynamic machinery. In this paper, the NACA0009 blunt trailing edge hydrofoil is used as the object of study, and the dynamic stall characteristics of the hydrofoil are investigated by using the transition model and the dynamic mesh method. It is found that the hydrofoil deep stall calculated by the transition model is delayed compared to that calculated without the transition model. The hydrofoil dynamic stall can be divided into four stages, initial stage, development stage, stall inception stage and deep stall stage. In the initial stage and the development stage, the lift and drag characteristics are influenced by the shedding vortex. In the stall inception stage and the deep stall stage, the lift and drag characteristics are influenced by the leading edge separation vortex and the trailing edge vortex. The increase of angular velocity and Reynolds number of the dynamic hydrofoil delay the onset of the deep stall while accelerating the boundary layer transition. The research in this paper has a certain guiding effect for the safe and stable operation of hydrodynamic machinery.</p

A unified element stiffness matrix model for variable cross-section flexure hinges in compliant mechanisms for micro/nano positioning

This paper presents a unified analytical model of element stiffness matrix for variable cross-section flexure hinges in plane deformation which is most frequently employed in planar-motion compliant mechanisms for micro/nano positioning. The unified analytical model is derived for flexure hinges in plane deformation based on the principle of virtual work. The derivation is generalized such that it can be applied to various geometries. To optimize and simplify element stiffness matrix model, four coefficients with curve integral are introduced. The results of the analysis were validated in part by modeling several previously investigated configurations, namely flexible beam hinge and right circular hinge. To further validate the proposed analytical model, finite element analysis and experimental testing were used. And the experimental testing shows the proposed unified model is more precise than pseudo-rigid-body method. The proposed model provides a concise and generalized solution to derive the element stiffness matrices of flexible hinges in plane deformation, which will have excellent applications in design and analysis of variable cross-section flexible hinges in compliant mechanisms

Understanding the Kinetic Energy deposition within Molecular Clouds

According to the structures traced by $^{13}$CO spectral lines within the $^{12}$CO molecular clouds (MCs), we investigate the contributions of their internal gas motions and relative motions to the total velocity dispersions of $^{12}$CO MCs. Our samples of 2851 $^{12}$CO MCs harbor a total of 9556 individual $^{13}$CO structures, among which 1848 MCs ($\sim$ 65$\%$) have one individual $^{13}$CO structure and the other 1003 MCs ($\sim$ 35$\%$) have multiple $^{13}$CO structures. We find that the contribution of the relative motion between $^{13}$CO structures ($\sigma_{\rm ^{13}CO, re}$) is larger than that from their internal gas motion ($\sigma_{\rm ^{13}CO, in}$) in $\sim$ 62$\%$ of 1003 MCs in the `multiple' regime. In addition, we find the $\sigma_{\rm ^{13}CO, re}$ tends to increase with the total velocity dispersion($\sigma_{\rm ^{12}CO, tot}$) in our samples, especially for the MCs having multiple $^{13}$CO structures. This result provides a manifestation of the macro-turbulent within MCs, which gradually becomes the dominant way to store the kinetic energy along with the development of MC scales.Comment: 15 pages, 13 figures, accepted for publication in Ap

Ferroelectricity, Piezoelectricity, and Dielectricity of 0.06PMnN-0.94PZT(45/55) Thin Film on Silicon Substrate

The high piezoelectricity and high quality factor ferroelectric thin films are important for electromechanical applications especially the micro electromechanical system (MEMS). The ternary compound ferroelectric thin films 0.06Pb(Mn1/3, Nb2/3)O3 + 0.94Pb(Zr0.45, Ti0.55)O3 (0.06PMnN-0.94PZT(45/55)) were deposited on silicon(100) substrates by RF magnetron sputtering method considering that Mn and Nb doping will improve PZT properties in this research. For comparison, nondoped PZT(45/55) films were also deposited. The results show that both of thin films show polycrystal structures with the main (111) and (101) orientations. The transverse piezoelectric coefficients are e31,eff=−4.03 C/m2 and e31,eff=-3.5 C/m2, respectively. These thin films exhibit classical ferroelectricity, in which the coercive electric field intensities are 2Ec=147.31 kV/cm and 2Ec=135.44 kV/cm, and the saturation polarization Ps=30.86 μC/cm2 and Ps=17.74 μC/cm2, and the remnant polarization Pr=20.44 μC/cm2 and Pr=9.87 μC/cm2, respectively. Moreover, the dielectric constants and loss are εr=681 and D=5% and εr=537 and D=4.3%, respectively. In conclusion, 0.06PMnN-0.94PZT(45/55) thin films act better than nondoped films, even though their dielectric constants are higher. Their excellent ferroelectricity, piezoelectricity, and high power and energy storage property, especially the easy fabrication, integration realizable, and potentially high quality factor, make this kind of thin films available for the realistic applications

Droplet spatial distribution of oil-based emulsion spray

IntroductionOil-based emulsion solution is a common pesticide formulation in agricultural spraying, and its spray characteristics are different from that of water spraying. The well understanding of its spray characteristics is the theoretical basis to improve the pesticide spraying technology. The objective of the present study is to deepen the understanding of the spray characteristics of oil-based emulsion.MethodIn this paper, the spatial distribution characteristics of spray droplets of oil-based emulsion were captured visually using the high-speed photomicrography. On the basis of image processing method, the droplet size and distribution density of spray droplets at different spatial locations were analyzed quantitatively. The effects of nozzle configuration and emulsion concentration on spray structures and droplet spatial distribution were discussed.ResultsOil-based emulsion produced a special perforation atomization mechanism compared with water spray, which led to the increase of spray droplet size and distribution density. Nozzle configuration had a significant effect on oil-based emulsion spray, with the nozzle changed from ST110-01 to ST110-03 and ST110-05; the sheet lengths increased to 18 and 28 mm, respectively, whereas the volumetric median diameters increased to 51.19% and 76.00%, respectively. With emulsion concentration increased from 0.02% to 0.1% and 0.5%, the volumetric median diameters increased to 5.17% and 14.56%, respectively.DiscussionThe spray droplet size of oil-based emulsion spray can be scaled by the equivalent diameter of discharge orifice of nozzles. The products of volumetric median diameters and corresponding surface tensions were nearly constant for the oil-based emulsion spray of different emulsion concentrations. It is expected that this research could provide theoretical support for improving the spraying technology of oil-based emulsion and increasing the utilization of pesticide