Search

研究科: 千葉大学大学院医学薬学府（先端創薬科学専攻）, 学位記番号: 千大院医薬博甲第薬科80号

We studied optimized conditions for preparing ternary hot extrudates (HEs) of glibenclamide (GLB)/polyvinylpyrrolidone (PVP)/sodium dodecyl sulfate to generate stable nanocrystal suspensions following aqueous dispersion. Raman and solid-state NMR measurements of ternary HEs prepared by altering HE conditions revealed that GLB crystallinity in HEs reduced with increased extrusion temperature and count and decreased screw speed. Aqueous dispersions of all HEs temporarily formed GLB nanoparticles with a diameter of 75-420 nm. The suspension from the HEs with the low GLB crystallinity (22%) precipitated after 4-h storage, while the HEs with the high GLB crystallinity (22%) formed stable nanocrystal suspension. Interestingly, the number of GLB nanoparticles150 nm was different despite aqueous dispersion of HEs with similar GLB crystallinity, reflecting the different GLB crystalline size in those HEs. Although both the crushing by shear force and GLB dissolution into PVP reduced GLB crystalline size, the crushing GLB crystal by the shear force has a relatively high ability to decrease GLB crystalline size without excess amorphization of GLB. Performing the hot extrusion at a low temperature, a high screw speed, and maximizing extrusion count with GLB crystallinity22% led to formation of small and stable nanocrystal suspensions.

Carbon-supported PtCu catalysts (PtCu/C) with different copper doping amounts were prepared by ion beam sputtering (IBS), followed by electrolytic corrosion. Inductively coupled plasma-atomic emission spectrometry (ICP-AES) results indicated that Pt loading capacity and the atom ratio of copper and platinum decreased. X-ray photoelectron spectroscopy (XPS) confirmed the elementary existence of platinum at the near surface. X-ray diffraction (XRD) results indicated that the catalysts formed Pt1Cu1 or Pt1Cu3 alloy. High resolution transmission electron microscopy (HR-TEM) results showed PtCu/C catalysts featured pores surfaces, the number of pores and the surface roughness increased with the atom ratio of copper and platinum decreasing. Cyclic voltammetry (CV) and linear sweep voltammetry (LSV) results indicated that the hydrogen evolution catalytic performance of PtCu/C catalysts was improved remarkably by Cu doping and electrolytic corrosion.

Pt–Cu/C catalysts are synthesized by an ion beam sputtering (IBS) apparatus, followed by annealing in vacuum, and then electrochemical etching with 0.5 M H2SO4 aqueous solution for different times. Electrochemical results show that the sample that was modified electrochemically for 5 h possesses the best electro-catalytic properties. Compared with a Pt/C catalyst, its performance was enhanced by approximately 36.79% and Pt loadings decreased by about 44.70%, indicating the characteristics of lower Pt consumption with higher catalytic activity. Furthermore, the corrosion time is likely to be between 5 and 6 h for its best catalytic activity. XPS studies indicate that a certain correlation between binding energy and electrocatalytic activity is of great significance for regulating binding energy to obtain high catalytic performance.

The cucumber mosaic virus (CMV) 2b protein is an RNA silencing suppressor protein that can also play direct and indirect roles in symptom induction. Previous work has shown that a hybrid virus, FRad35(2b)‐CMV (renamed here as CMV‐FRad2b‐Pro), generated by replacement of the 2b gene of strain Fny‐CMV with that from Rad35‐CMV, displays markedly lower pathogenicity than Fny‐CMV on N icotiana species. However, the replacement of proline with leucine at position 55 of the 2b protein of CMV‐FRad2b‐Pro (protein Rad2b‐Pro) created a virus (CMV‐FRad2b‐Leu) that induced severe symptoms. Infection of A rabidopsis thaliana mutants defective in the expression of DICER‐like (DCL) endoribonucleases 2 and 4, which mediate antiviral RNA silencing, as well as of dcl3 and dcl2/3/4 triple‐mutant plants, indicated that Rad2b‐Pro was a weaker RNA silencing suppressor than the protein Rad2b‐Leu. This was confirmed in N icotiana benthamiana using agroinfiltration assays, showing that, compared with either Rad2b‐Leu or the Fny2b protein, Rad2b‐Pro was ineffective at inhibiting local or systemic silencing of expression of a green fluorescent protein reporter gene. Transgenic expression of Rad2b‐Leu, but not of Rad2b‐Pro, in A rabidopsis induced symptom‐like phenotypes and rescued the accumulation of the 2b‐deletion mutant Fny‐CMVΔ2b. Bimolecular fluorescent complementation indicated that, in planta, Rad2b‐Leu, but not Rad2b‐Pro, self‐interacts. Thus, self‐interaction is crucial to the ability of the 2b protein to suppress silencing and induce a symptom‐like phenotype, and is dependent on the properties of the residue at position 55.

Currently, the food security situation is increasingly serious, and a growing number of food companies choose to implement the internationally accepted ISO9000 Series Standards. Based on the analysis of economic rationality and system drive for food enterprises to implement ISO9000 Series Standards, we determine the economic factors and institutional factors influencing enterprises' implementation of ISO9000 Series Standards, and establish corresponding indicator system. According to survey data on 86 enterprises in Sichuan Province, we draw the following conclusion using the Logit model: enterprise age and enterprise size in economic factors, government's food safety control intensity, consumers, public and media pressure, awareness of senior managers, strategic orientation of quality safety, employees' average educational level in institutional factors, have a significant effect on enterprises' implementation of ISO9000 Series Standards. According to research results, we put forth some recommendations for promoting food enterprises to implement ISO9000 Series Standards.

Currently, the food security situation is increasingly serious, and a growing number of food companies choose to implement the internationally accepted ISO9000 Series Standards. Based on the analysis of economic rationality and system drive for food enterprises to implement ISO9000 Series Standards, we determine the economic factors and institutional factors influencing enterprises' implementation of ISO9000 Series Standards, and establish corresponding indicator system. According to survey data on 86 enterprises in Sichuan Province, we draw the following conclusion using the Logit model: enterprise age and enterprise size in economic factors, government's food safety control intensity, consumers, public and media pressure, awareness of senior managers, strategic orientation of quality safety, employees' average educational level in institutional factors, have a significant effect on enterprises' implementation of ISO9000 Series Standards. According to research results, we put forth some recommendations for promoting food enterprises to implement ISO9000 Series Standards.

CeO x/ C supported PtCu thin film catalysts were prepared by ion beam sputtering (IBS) and subsequently annealed at 400°C under vacuum environment and electrochemically dealloyed. Scanning transmission electronic microscope (STEM) and atomic force microscope (AFM) characterizations show that the surface of post-processed catalyst presents nanoporous structure and has a high root mean square roughness (RMS = 13.9nm). Electrochemical measurements indicate that the post-processed PtCu – CeO x/ C catalyst shows higher catalytic activity towards hydrogen evolution reaction than pure Pt / C . While inductively coupled plasma atomic emission spectroscopy (ICP-AES) analysis displays that the platinum ( Pt ) loading of the post-processed PtCu – CeO x/ C is 0.1192mg/cm2, decreasing by 20% compare to pure Pt / C (0.1490mg/cm2). X-ray photoelectron spectroscopy (XPS) analysis confirms that the surface of post-processed PtCu – CeO x/ C enrich Pt and analyzes the chemical valence of Pt element using depth profiling technology. It can be inferred that the enhancement in catalytic property is attributed to the combined action between geometric structure effect and electronic modification effect of Pt atoms from CeO x support.