Cerium-doped glasses usually contain a mixture of Ce3+ and Ce4+ species, with the trivalent state being dominant. Quantitative determination of the redox ratio is complicated by the narrow energy gap between both states, leading to spectral overlap in optical absorption studies, and strong beam sensitivity in other techniques. However, it also indicates a way to induce electric conduction through electron hopping, with the additional benefit of visual transparency. Here, cerium phosphate glasses are reported in which the local optical basicity is varied through substitution of cerium by highly polarizable rubidium ions. This is done in order to control the Ce3+/ Ce4+ ratio. Electrical impedance spectroscopy is considered as an alternative means to assess the redox ratio by exploring the extent of polaron conduction. Complementary Raman and 31P MAS NMR spectroscopic studies provide structural insight on the process of mixed electronic and ionic charge transport. Meanwhile, a monotonic decrease in the elastic modulus and an abnormal change in Poisson's ratio when varying the composition corroborate structural interpretations.
The authors demonstrate that the micro magneto-rheological fluid device is designed by the method of outer magnetic coil to generate a mechanical loading less than 20 N. The results confirm that the method can obtain miniature device easily and control the magnetic field conveniently. The magnetic field, the channel gap, and the initial position of valve plug were optimized by finite element simulation and experimental test. Additionally, an impact force at the beginning can be eliminated by using a modeled synchronous linear current, which indicates that the micro-magnetorheological fluid damper has good soft-landing performance.
Annealed high speed steels for making tools such as W6Mo5Cr4V2, W9Mo3Cr4V1, W18Cr4V were treated with 5 kw continuous adjusting CO2 laser. By controlling laser- processing parameters, we achieved variable datum about the depth and hardness of the surface hardening layer of the samples. The relationship between the depth of hardening layer and laser processing parameters were studied with microhardness meter, scanning electronic microscope. The results showed that the sample's micro organization was markedly fined, dislocation and twin crystal subconstruction was strikingly increased, its hardness was obviously higher than that of general heat treatment.
Background/Aims: Dilated intercellular space (DIS) contributes to the pathophysiology of gastroesophageal reflux disease (GERD). Melatonin protects the esophageal mucosa; however, the mechanisms underlying that protection remain unclear. Methods: Transmission electron microscopy (TEM) was used to evaluate the intercellular spaces in the esophageal epithelium of GERD patients. The Het-1A monolayer barrier function was investigated by measuring transepithelial resistance (TER) and FITC-dextran paracellular permeation. The activity of MLCK was represented by MLC phosphorylation. The expression and phosphorylation of MLCK, MLC and ERK were examined by western blot analysis. Results: The expression and activity of MLCK and ERK phosphorylation were increased in the esophageal epithelium. The increased expression and activity of MLCK was correlated with dilated intercellular spaces. Upon acid treatment, the Het-1A monolayer permeability was increased. When the Het-1A monolayer was pretreated with melatonin and PD98059 before the acid incubation, the permeability and the expression and phosphorylation of MLCK and ERK decreased. Conclusion: Melatonin protects the esophageal epithelial barrier by suppressing the transcription, translation and activity of MLCK through ERK1/2 signal transduction. These findings provide a better understanding of the potential clinical application of melatonin in GERD treatment.
Liposarcoma is one of the most common mesenchymal tumors, although liposarcomas that occur in the mediastinum are uncommon. We recently encountered a case of mediastinal well-differentiated liposarcoma with secondary myxoid changes and smooth muscle differentiation in a 54-year-old man. The patient reported a 20-day history of chest pain, and thorax computed tomography revealed a large and multilobulated mass with heterogeneous density in the posterior and anterior mediastinum, which extended to the right hemithorax. Resection was performed and a pathological analysis subsequently confirmed a diagnosis of well-differentiated liposarcoma. The patient experienced recurrence at 15 months after the surgery and subsequently died of heart failure.
Poly(butylene-carbonate) is a potential alternative to poly(ε-caprolactone) for biomedical application. Although mechanical properties of porous poly(butylene-carbonate) membranes were inferior to poly(ε-caprolactone), its contact angles (47.41° ± 1.17°) were lower than poly(ε-caprolactone) (77.24° ± 0.54°) (p < 0.001). It degraded faster than poly(ε-caprolactone) during a 10-week in vitro experiment (p < 0.01). Moreover, it had excellent bioactivity during simulated body fluid immersion. Cell spreading on poly(butylene-carbonate) was better than that on poly(ε-caprolactone). Cell behavior tests including cytotoxicity, proliferation, and differentiation were performed. The poly(butylene-carbonate) is more compatible with cells and promotes cell differentiation. In vivo, the defects covered by poly(butylene-carbonate) and poly(ε-caprolactone) membranes had a similar degree of regeneration at 4 weeks. It was concluded that poly(butylene-carbonate) could potentially be used to guide bone regeneration, and it is a potential new biodegradable polymer.
This paper presents the structure characteristics,the functionality and the working principle underlying portable fingerprints collector of FPS200,which is a new type of CMOS fingerprint sensor chip.It designs the details of hardware electric circuits,software interface and the software control-flow of reading fingerprints based on FPS200 in the USB model.
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