NIMA-related kinases 6, 4, and 5 interact with each other to regulate microtubule organization during epidermal cell expansion in Arabidopsis thaliana

NimA-related kinase 6 (NEK6) has been implicated in microtubule regulation to suppress the ectopic outgrowth of epidermal cells; however, its molecular functions remain to be elucidated. Here, we analyze the function of NEK6 and other members of the NEK family with regard to epidermal cell expansion and cortical microtubule organization. The functional NEK6-green fluorescent protein fusion localizes to cortical microtubules, predominantly in particles that exhibit dynamic movement along microtubules. The kinase-dead mutant of NEK6 (ibo1-1) exhibits a disturbance of the cortical microtubule array at the site of ectopic protrusions in epidermal cells. Pharmacological studies with microtubule inhibitors and quantitative analysis of microtubule dynamics indicate excessive stabilization of cortical microtubules in ibo1/nek6 mutants. In addition, NEK6 directly binds to microtubules in vitro and phosphorylates beta-tubulin. NEK6 interacts and co-localizes with NEK4 and NEK5 in a transient expression assay. The ibo1-3 mutation markedly reduces the interaction between NEK6 and NEK4 and increases the interaction between NEK6 and NEK5. NEK4 and NEK5 are required for the ibo1/nek6 ectopic outgrowth phenotype in epidermal cells. These results demonstrate that NEK6 homodimerizes and forms heterodimers with NEK4 and NEK5 to regulate cortical microtubule organization possibly through the phosphorylation of beta-tubulins

ICNMM2007-30109 OPTIMAL SHAPE DESIGN OF PRESSURE-DRIVEN MICROCHANNELS USING ADJOINT VARIABLE METHOD

ABSTRACT The shape of microchannels is an important design variable to achieve the desired performance. Since most microchannels are, at present, designed by trial and error, a systematic optimal shape design method needs to be established. Computational fluid dynamics (CFD) is often used to rigorously examine the influence of the shape of microchannels on heat and mass transport phenomena in the flow field. However, the rash combination of CFD and the optimization technique based on evaluating gradients of the cost function requires enormous computation time when the number of design variables is large. Recently, the adjoint variable method has attracted the attention as an efficient sensitivity analysis method, particularly for aeronautical shape design, since it allows one to successfully obtain the shape gradient functions independently of the number of design variables. In this research, an automatic shape optimization system based on the adjoint variable method is developed using C language on a Windows platform. To validate the effectiveness of the developed system, pressure drop minimization problems of a 180° curved microchannel and a branched microchannel in incompressible flows under constant volume conditions are solved. These design examples illustrate that the pressure drop of the optimally designed microchannels is decreased by about 20 % ~ 40 % as compared with that of the initial shape

Thermodynamic Analysis of the Phase Equilibria in the Fe-Zr-B System

A thermodynamic analysis of the Fe-Zr-B ternary system has been carried out using the CALPHAD method. Among the three binary systems present in the ternary phase diagram, the thermodynamic descriptions of the Fe-Zr and Fe-B binary systems were taken from reported results and from our previous study, respectively. The thermodynamic parameters of the Zr-B binary system were evaluated using the thermochemical properties from our first-principles calculations, as well as available experimental data. In this modelling, the Gibbs energy of ZrB 2 with an AlB 2 -type structure was represented using the two-sublattice model, in which vacancies were introduced into both the Zr and the B sublattices, following the recent data obtained from neutron diffraction experiments on NbB 2 with the same structure as that of ZrB 2 . The optimized thermodynamic parameters of the Zr-B system enabled us to obtain reproducible calculations of the experimental data on phase boundaries and formation enthalpies obtained from first-principles calculations. The ternary parameters were determined using the experimental data on phase boundaries. The calculated results have nicely reproduced the experimental Fe-Zr-B ternary phase diagrams

Hybrid Pixel Devices with SOI-Si photodiode and 4H-SiC MOSFETs for Radiation-Hardened Image Sensors

For the electronics, radiation hardness has been required especially for decommissioning of the Fukushima Daiichi nuclear power station. So far for such the decommissioning operations, many robots have been installed, however the available time for operation is limited by electronics, in particular, image sensors. At a pixel device in a conventional Si CMOS image sensor, Si MOSFETs as reset (RST), source follower (SF), row selector (RS) , are sensitive and vulnerable to radiation, rather than Si photodiodes (PD). Then a combination of Silicon carbide (SiC) MOSFETs and Si PD would be a candidate for the pixel device of the radiation-hardened CMOS image sensors. In this work, SOI (Silicon-On-Insulator)-Si PD and 4H-SiC MOSFETs were integrated in a same substrate for the radiation hardened image sensors. The typical feature size of the SOI-Si PD was 500 μm2 and that of 4H-SiC MOSFET was channel length/ width = 10 μm/ 50 μm. Under dark condition, the output voltage shift from the reset state was 0.62 V. On the other hand, under visible light of 7 klux, the output voltage shift became 0.74 V. The voltage difference between dark and visible-light illuminated condition was dependent on the reset (RST) frequency. As the RST frequency decreased from 100Hz, the voltage difference became larger. As the results, the hybrid pixel devices with SOI-Si PD and 4H-SiC MOSFETs were sucessfully demonstrated.European Conference on Silicon Carbide and Related Materials (ECSCRM 2018

Direct Bonding of 4H-SiC and SOI Wafers for Radiation-Hardened Image Sensors

4H-SiC and SOI substrates were bonded by SiO2-SiO2 direct bonding method with diluted HF solution (0.5 wt.%). After the bonding process, the handle layer and the BOX layer of the SOI substrate were etched by TMAH solution, and finally the silicon active layer with a thickness of 1.5 μm was remained on the 4H-SiC substrate. Using this silicon layer, Si photodiodes on 4H-SiC for the radiation hardened image sensors were fabricated and demonstrated