Targeted gene replacement at the URA3 locus of the basidiomycetous yeast Pseudozyma antarctica and its transformation using lithium acetate treatment

The basidiomycetous yeast Pseudozyma antarctica is a remarkable producer of industrially valuable enzymes and extracellular glycolipids. In this study, we developed a method for targeted gene replacement in P. antarctica. In addition, transformation conditions were optimized using lithium acetate, single‐stranded carrier DNA and polyethylene glycol (lithium acetate treatment), generally used for ascomycetous yeast transformation. In the rice‐derived P. antarctica strain GB‐4(0), PaURA3, a homologue of the Saccharomyces cerevisiae orotidine‐5′‐phosphate decarboxylase gene (URA3), was selected as the target locus. A disruption cassette was constructed by linking the nouseothricine resistance gene (natMX4) to homologous DNA fragments of PaURA3, then electroporated into the strain GB‐4(0). We obtained strain PGB015 as one of the PaURA3 disruptants (Paura3Δ::natMX4). Then the PCR‐amplified PaURA3 fragment was introduced into PGB015, and growth of transformant colonies but not background colonies was observed on selective media lacking uracil. The complementation of uracil‐auxotrophy in PGB015 by introduction of PaURA3 was also performed using lithium acetate treatment, which resulted in a transformation efficiency of 985 CFU/6.8 μg DNA and a gene‐targeting ratio of two among 30 transformants. Copyright © 2017 John Wiley & Sons, Ltd.     

Fabrication of conductive oxide polycrystalline BaPbO3 films by chemical solution deposition and their electrical resistivity

BaPbO₃ films were fabricated by a chemical solution deposition on the SiO₂/Si(100) and MgO(100) substrates followed by a post-deposition annealing at the temperatures between 673 and 1073 K under oxygen flow. Polycrystalline BaPbO₃ films were formed together with secondary phases such as PbO and Pb₃O₄ onto MgO(100) substrates at around 750 K, and the films were crystallized into single phase of BaPbO₃ above 823 K. Endothermic peak in differential thermal analysis due to crystallization of BaPbO₃ was observed at 750 K, which is consistent with crystallization temperature of BaPbO₃ estimated from X-ray diffraction. The electrical resistivity depended on the annealing temperature even in the single phase BaPbO₃ films, the lowest resistivity of 3?×?10^?6 μΩ·m which was comparable to that of bulk BaPbO₃ was achieved at the annealing temperature of 873 K.     

Assessment of dynamical properties in EDM process—detecting signature of latent change to deleterious process in advance

Time series data of gap state were often used as feedback signal in EDM control systems. An effective way to quantify gap state in machining was developed in this paper. Based on a time series of gap states recording a machining process, the entire process was partitioned into three parts, transient process, efficient machining process, and deleterious process. It is expected that efficient machining process should be maintained long enough in consideration of machining efficiency and avoiding workpiece surface damage. In this case, a signature of structural change from efficient machining process to deleterious process has to be detected or detected in advance. It has been found that linear analysis methods failed the task. In this paper, a nonlinear analysis method, cross-prediction error, was employed to track this structural change in efficient machining process in two tests. In the first test, the efficient machining process was roughly split into 30 segments. By using the cross-prediction-error method in this test, the non-stationarity, a signature of structural change from stationary process in efficient machining process to non-stationary process, was successfully revealed in the last segment of the process. In another test, efficient machining process was even more finely split into 70 segments, and by using the cross-prediction-error method again it is found that the detected non-stationarity in the process was in the last segment but one. The second test not only proves the effectiveness of the method, but also brings forward the detected non-stationarity more than 10s. The detected non-stationarity in advance, thus, is supposed to be used for avoiding the occurrence of abnormal deleterious process and maintaining a persisted efficient machining process.     

Assessment of the dynamical properties in EDM process—detecting deterministic nonlinearity of EDM process

Time series of gap state were often used as feedback signal in electrical discharge machining (EDM) adaptive control systems. However, models precisely describing the EDM process have never been built because of the once believed stochastic nature of the EDM process. In this case, the power of adaptive controls in EDM had not been fully brought into play. Before building a feasible model, it is prerequisite to determine whether an efficient stable EDM process is nonlinear or linear, deterministic or stochastic. The main purpose of this paper is to investigate the deterministic nonlinearity of the process. A discriminating method was first provided to judge states in the gap at sampling intervals from voltage and current. Gap state was then statistically quantified from a train of discriminated states at sampling intervals within a specified period of time. Based on a time series of gap state data, we took use of surrogate data method to detect the nonlinearity of the process. From the results of two kinds of tests, it can be concluded that the deterministic nonlinearity of the process reflected by gap states is intrinsic.     

Electronic Conductivity of La-Doped Ceria Ceramics

Lanthanum-doped ceria powder with a composition Ce_0.8La_0.2O_1.9 was prepared by heating the oxalate solid solution (Ce_0.8La_0.2)₂(C₂O₄)₃ at 873 K in air. As-prepared powder was densified to 96%–97% relative density by sintering in air at 1773 K for 4 h. The electronic current of the disk sample was measured in a temperature range from 773 to 1113 K by the direct current polarization method using a Hebb–Wagner ion-blocking cell. A linear relationship, which was theoretically predicted, was measured between log σ_e (electronic conductivity) and E (applied voltage) in the applied voltage range of 0.2–1.0 V. The σ_e was proportional to P _O2^−1/4.3≈ P _O2^−1/4.6 in the oxygen partial pressure range of 10⁻²–10⁻⁸ Pa, and to P _O2^−1/6.7≈ P _O2^−1/7.1 in the oxygen partial pressure range of 10^−7.5–10⁻²² Pa. The apparent activation energy of the electronic conduction was 1.87–1.94 eV. The hole conduction was also measured in the P o₂ range of 10²–10⁵ Pa. The transport number of oxide ion was 0.96–1.00 at 773–1113 K under an oxygen partial pressure of 10⁻⁵ Pa.     

Development of electrochemical cell with layered composite of the Gd-doped ceria/electronic conductor system for generation of H2–CO fuel through oxidation–reduction of CH4–CO2 mixed gases

This paper shows the recent results on the development of layered composite promoting two types of electrochemical reactions (oxidation and reduction) in one cell. This cell consisted of porous Ni–Gd-doped (GDC) ceria cathode/thin porous GDC electrolyte (50 μm)/porous SrRuO₃–GDC anode. The external electric current was flowed in this cell at the electric field strength of 1.25 and 6.25 V/cm. The mixed gases of CH₄ (30–70%) and CO₂ (70–30%) were fed at the rate of 50 ml/min to the cell heated at 400–800 °C under the electric field. In the cathode, CO₂ was reduced to CO (CO₂ + 2e^? → CO + O^2?) and the formed CO and O^2? ions were transported to the anode through the pores and surface and interior of grains of GDC film. On the other hand, CH₄ was oxidized in the anode to form CO and H₂ through the reaction with diffusing O^2? ions (CH₄ + O^2? → CO + 2H₂ + 2e^?). As a result, H₂–CO mixed fuel was produced from the CH₄–CO₂ mixed gases (CH₄ + CO₂ → 2H₂ + 2CO). This electrochemical reaction proceeded completely at 800 °C and no blockage of gases was measured for long time (>10 h). Only H₂–CO fuel was generated in the wide gas compositions of starting CH₄–CO₂ gases.     

电火花加工间隙流场的三维仿真研究

间隙流场中加工屑的分布是影响火花放电频率和放电点分布的重要因素,并直接关系到加工速度与加工精度,对间隙流场中加工屑分布情况进行研究是提高加工速度、加工精度的重要途径之一.该研究在对间隙流场中工作液和加工屑的运动进行理论分析的基础上,建立间隙流场的三维仿真模型,进行电极上下往复运动过程中间隙流场和加工屑运动的仿真计算,验证实验的结果证明了仿真方法的正确性.     

Wavefield characterization of nearly diffraction-limited focused hard x-ray beam with size less than 10 nm

In situ wavefront compensation is a promising method to realize a focus size of only a few nanometers for x-ray beams. However, precise compensation requires evaluation of the wavefront with an accuracy much shorter than the wavelength. Here, we characterized a one-dimensionally focused beam with a width of 7 nm at 20 keV using a multilayer mirror. We demonstrate that the wavefront can be determined precisely from multiple intensity profiles measured around the beamwaist. We compare the phase profiles recovered from intensity profiles measured under the same mirror condition but with three different aperture sizes and find that the accuracy of phase retrieval is as small as λ∕12.     

Preclinical and Clinical Evidence of Therapeutic Agents for Paclitaxel-Induced Peripheral Neuropathy

Paclitaxel is an essential drug in the chemotherapy of ovarian, non-small cell lung, breast, gastric, endometrial, and pancreatic cancers. However, it frequently causes peripheral neuropathy as a dose-limiting factor. Animal models of paclitaxel-induced peripheral neuropathy (PIPN) have been established. The mechanisms of PIPN development have been elucidated, and many drugs and agents have been proven to have neuroprotective effects in basic studies. In addition, some of these drugs have been validated in clinical studies for their inhibitory PIPN effects. This review summarizes the basic and clinical evidence for therapeutic or prophylactic effects for PIPN. In pre-clinical research, many reports exist of neuropathy inhibitors that target oxidative stress, inflammatory response, ion channels, transient receptor potential (TRP) channels, cannabinoid receptors, and the monoamine nervous system. Alternatively, very few drugs have demonstrated PIPN efficacy in clinical trials. Thus, enhancing translational research to translate pre-clinical research into clinical research is important.