Electrospun curcumin/polycaprolactone/copolymer F-108 fibers as a new therapy for wound healing

The application of fibers associated with drugs is a promising alternative to meet the clinical needs of tissue repair. Curcumin exhibits great cicatricial potential because it has numerous pharmacological properties. This research aimed to produce fibers of polycaprolactone and copolymer F-108 associated with curcumin and to evaluate in vivo their action on the process of wound healing. The fibers were produced by electrospinning technique and characterized by scanning electron microscopy (SEM), X-ray diffractometry (XRD), and fluorescence microscopy. They were applied in cutaneous wounds of rats for the analysis of photoacoustic permeation and histological study. The characterization showed that the electrospinning allowed the preparation of homogeneous material with curcumin. The fibers benefited healing of the wounds and allowed the permeation of curcumin at all stages. The use of PCL/F-108 fibers allowed the elaboration of a new curcumin delivery system, improving its bioavailability and action in the healing of excisional wound. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48415.     

等温淬火温度对奥贝球铁水脆化行为的影响

研究了等温淬火温度对奥贝球铁(ADI)水脆化行为的影响，水附着条件下不同等温淬火温度处理的ADI均发生水脆化行为，抗拉强度和伸长率显著降低；但随着等温淬火温度升高，ADI的水脆化程度降低。高强度的ADI、淬火回火球铁和珠光体球铁均发生水脆化行为，而铁素体含量高的铸态球铁和铁素体球铁无明显的水脆化行为。     

Non-linear current–voltage characteristics related to native defects in SrTiO3 and ZnO bicrystals

SrTiO₃ and ZnO bicrystals with various types of boundaries were fabricated in order to examine their current–voltage characteristics across single grain boundaries. Their grain boundary structures were also investigated by high-resolution transmission electron microscopy. In Nb-doped SrTiO₃, electron transport behaviors depend on the type of boundaries. Random type boundaries exhibit highly non-linear current–voltage characteristics, while low angle boundaries show a slight non-linearity. On the contrary, undoped ZnO does not exhibit non-linear current–voltage characteristics in any type of boundaries including random ones. It is suggested that the differences observed in current–voltage properties between the two systems are mainly due to the difference in the accumulation behavior of acceptor-like native defects at grain boundaries. A clear non-linearity is obtained by means of Co-doping even for the highly coherent Σ1 boundary in a ZnO bicrystal. This is considered to result from the production of acceptor-like native defects by Co-doping.     

Carbon Nitride Loaded with an Ultrafine,Monodisperse, Metallic Platinum-Cluster Cocatalyst for the Photocatalytic Hydrogen-Evolution Reaction

For the realization of a next-generation energy society, further improvement in the activity of water-splitting photocatalysts is essential. Platinum (Pt) is predicted to be the most effective cocatalyst for hydrogen evolution from water. However, when the number of active sites is increased by decreasing the particle size, the Pt cocatalyst is easily oxidized and thereby loses its activity. In this study, a method to load ultrafine, monodisperse, metallic Pt nanoclusters (NCs) on graphitic carbon nitride is developed, which is a promising visible-light-driven photocatalyst. In this photocatalyst, a part of the surface of the Pt NCs is protected by sulfur atoms, preventing oxidation. Consequently, the hydrogen-evolution activity per loading weight of Pt cocatalyst is significantly improved, 53 times, compared with that of a Pt-cocatalyst loaded photocatalyst by the conventional method. The developed method is also effective to enhance the overall water-splitting activity of other advanced photocatalysts such as SrTiO₃ and BaLa₄Ti₄O₁₅.     

A new detection method for the primary cosmic heavy nuclei by the plastic track detector CR-39

A new multiple scanning method is developed and applied to detect cosmic heavy nuclei. The plastic track detectors CR-39 exposed to cosmic heavy nuclei are over-etched in 8.0N NaOH for 94 h at 80°C. We found that the etched cones can easily be scanned on the plastic plates without using an optical microscope. The trajectories of heavy nuclei can be reconstructed with the naked eyes by superposing four or more over-etched plates. The charge detection threshold is obtained by this method, and appears to be 10. The charge resolution is estimated to be 1.0 charge units for iron nuclei. By adopting this method, the scanning time is much shortened and CR-39 plastic chamber size can easily be scaled up. The method is very useful for detecting particles with low flux intensity, like for searching magnetic monopoles or for measuring the high energy spectra of cosmic heavy nuclei.     

Magnetization measurement of 3He film adsorbed on sintered silver powder

The static magnetization of ³He film adsorbed on sintered silver powder has been measured for coverages from 0.10 to 0.54 atoms/»² in steps of 0.02 atoms/»² and at a coverage of 4.5 atoms/»². Below 0.20 atoms/»² the magnetization well obeys the Curie law, while above that coverage a ferromagnetic tendency appears. The coverage dependence of the magnetization greatly differs from that for graphite. At 0.23 atoms/»² the magnetization has apeak like that for graphite; however, the magnitude of the peak is not so large. Furthermore, a multipeak structure is found in the isotherm of the magnetization at 0.2 mK. It has two prominent peaks at 0.23 and 0.29 atoms/»², and two other peaks are found at 0.35 and 0.41 atoms/»². These appear periodically with an interval of 0.06 atoms/»², which is nearly equal to the coverage of one liquid layer.     

Mesoporous Co3O4 for low temperature CO oxidation: effect of calcination temperatures on their catalytic performance

Mesoporous Co3O4 particles are prepared by using mesoporous silica KIT-6 (with double gyroid Ia-3d symmetry) as a hard-template and Co(No3)2 x 6H2O as an inorganic precursor. In the former section, we investigate the effect of the calcination temperatures at which the Co salts are converted into Co3O4 inside the mesopores on the textural parameters of the products. The results of N2 adsorption-desorption analysis indicates that the calcination temperatures do not obviously affect the textural parameters such as the surface areas and pore volumes. However, when the calcination temperature reaches 800 degrees C, the mesostructural ordering is dramatically decreased, resulting in the reduction of the surface areas and pore volumes. After 800 degrees C calcination, the formation of large Co3O4 grains is partially confirmed on the particle surface by SEM observation. The grain size is much larger than the mesopore size of the original KIT-6, meaning the crystal growth is continuously occurred by breaking the rigid silica frameworks. In the latter section, we discuss the effect of the calcination temperatures and textural parameters on the catalytic activity for CO oxidation by both steady state and kinetic measurements. All mesoporous Co3O4 particles show a high catalytic activity, for example, -72 degrees C for sample calcined at 450 degrees C. Only 10 degrees C difference in T50 (the temperature of 50% conversion of CO) is found between the samples with the highest and lowest catalytic activity. The values of activation energy (Ea) and pre-exponential factor (A) per unit area are almost the same between two samples calcined at 450 degrees C and 800 degrees C. It is demonstrated that calcination process can not alter the essential catalytic property of mesoporous Co3O4 particles.     

Visualizing vitreous using quantum dots as imaging agents

Vitreous is transparent tissue located between the lens and the retina of the eye, thus, difficult to look at by even ophthalmological microscope. But vitreous is connected with some sight-threatening eye diseases, for example, retinal detachment, macular hole, epi-retinal membrane, and so forth. Quantum dots (QDs) have been applied to a wide range of biological studies by taking advantage of their fluorescence properties. We established a novel technique of aqueous colloidal QD (ACQD) as a vitreous lesion detector. When compared with some conventional dyes used for clinical situation, i.e. fluorescein, indocyanine green, and triamcinolone acetonide, ACQD exerted a higher performance to detect a Weiss Ring. Furthermore ACQD is also effective to perform vitrectomy, an eye surgery to cut and eliminate vitreous. Some functional structures in vitreous are detected clearly when ACQD was injected into an enucleated porcine eye. We demonstrated that ACQD enabled any ophthalmic surgeon to perform vitrectomy reliably, easily, and more safely. Taken together, the ACQD-oriented vitreous staining system will promote ophthalmological science, and it will raise the cure rate of eye diseases     

Microfabrication of polytetrafluoroethylene using SR direct etching

Polytetrafluoroethylene (PTFE) is a very attractive material for various fields because of its chemical resistance, insulation properties, and hydrophobic properties. However, it is difficult to fabricate PTFE microstructures with conventional techniques such as semiconductor processes or micromachining. We have succeeded in the fabrication of high‐aspect‐ratio microfluidics parts from PTFE by direct in‐vacuum photo‐etching utilizing synchrotron radiation (SR) at energy levels from 2 to 12 keV. This paper presents an analysis of the mechanisms of the PTFE microfabrication process and describes newly discovered processing characteristics of PTFE. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 178(4): 49–54, 2012; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21152     

Weighting matrix of quadratic performance index and design method of optimal deadbeat control system

A method of determination of the weighting matrix of the quadratic performance index and a method of design of an optimal deadbeat control system are discussed. First, the relationship between the weighting matrix of the quadratic performance index and the extra poles of the overparametrized pulse transfer function model is indicated. Next, a method of design of an optimal deadbeat control system is explained. Lastly, to demonstrate the effectiveness of the proposed method, some numerical examples are presented. © 2000 Scripta Technica, Electr Eng Jpn, 133(1): 53–63, 2000