Optical Fiber Displacement Sensor Based on Microwave Photonics Interferometry.

An optical fiber displacement sensor based on the microwave photonics interferometric (MWPI) method is proposed and experimented, which provides an ideal solution for large range displacement measurement with high resolution. The sensor used a Michelson microwave photonics interferometer to sense the displacement with one sensing arm and a length-adjusted reference arm. The displacement variation would change the period of the microwave response function of the interferometer. According to the principle that the phase difference in one free spectral range (FSR) of the microwave response function is 360°, the displacement can be retrieved by the microwave response function by means of a vector network analyzer (VNA). A programmable path-switching true time delay line was used in the reference arm to decrease the microwave bandwidth. The measurement results show that the displacement sensing range is larger than 3 m and the measurement resolution is 31 µm. Finally, the measurement stability is tested, and the factors affecting the measurement resolution of this method and the main source of errors are investigated in detail.

[Effect of isopsoralen on the proliferation and differentiate of osteoblasts in vitro].

OBJECTIVE: To investigate the effect of isopsoralen on proliferation, osteogenic differentiation and calcification capacity of rat calvarial osteoblasts (ROB). METHODS: Segregated neonatal SD rat skull,and digestion with enzyme to obtain bone cells and cultured in MEM containing 10% FBS. Exchange the medium after three days, proceeded serial subcultivation when cells covered with 90% culture dish. Proliferation analysis was performed in 96-well plates use MTT method, isopsoralen's final concentration were 1 x 10(-4), 1 x10(-5), 1 x 10(-6), 1 x 10(-7) mmol/L. Differentiation analysis was performed in 24-well plates, the Alkaline phosphatase activity and calcium salt sediment yield and osteocalcin measured at the 4th, 8th, 12th, 16th day. At 12th day, proceeded ALP stain, and at 14th day for alizarin red staining and calcified nodule count. RESULTS: When the Isopsoralen's final concentration was 1 x 10(-5) mmol/L, there was no significant effect on the ROB's proliferation, but it could promote osteogenesis. It also could raise the ALP activity and calcium salt sediment yield and osteocalcin, increase calcified tubercle amount. CONCLUSION: When the isopsoralen final concentration is 1 x 10(-5) mmol/L, it promoted ROB differentiation and maturation. Isopsoralen may be the active ingredients of preventing anti-osteoporosis in Psoralea corylifolia.

MXene-GaN van der Waals metal-semiconductor junctions for high performance multiple quantum well photodetectors.

A MXene-GaN-MXene based multiple quantum well photodetector was prepared on patterned sapphire substrate by facile drop casting. The use of MXene electrodes improves the responsivity and reduces dark current, compared with traditional Metal-Semiconductor-Metal (MSM) photodetectors using Cr/Au electrodes. Dark current of the device using MXene-GaN van der Waals junctions is reduced by three orders of magnitude and its noise spectral intensity shows distinct improvement compared with the traditional Cr/Au-GaN-Cr/Au MSM photodetector. The improved device performance is attributed to low-defect MXene-GaN van der Waals interfaces. Thanks to the high quality MXene-GaN interfaces, it is possible to verify that the patterned substrate can locally improve both light extraction and photocurrent collection. The measured responsivity and specific detectivity reach as high as 64.6 A/W and 1.93 × 1012 Jones, respectively, making it a potential candidate for underwater optical detection and communication. The simple fabrication of MXene-GaN-MXene photodetectors spearheaded the way to high performance photodetection by combining the advantages of emerging 2D MXene materials with the conventional III-V materials.

[Effects of rat serum containing total flavonoid extract of Epimedium sagittatum on development of osteoblasts].

OBJECTIVE: To investigate the effects of total flavonoid extract of Epimedium sagittatum (TFE) on the proliferation and differentiation of newborn rat calvarial osteoblasts (ROB). METHOD: TFE was supplemented into the culture medium of ROB at 0. 1, 1, 10 and 100 microg x mL(-1) respectively. The serum of rats administered TFES (SRAT) was also added into the medium in a parallel treatment at 2.5%, 5% and 10% respectively. Their effects on cell proliferation and differentiation was studied by MTT and the analysis of osteogenic differentiation marks. RESULT: TFE had no appreciable and on cell proliferation and differentiation at any concentration. However, 2.5% and 5% SRAT stimulated cell proliferation strongly and, 5% SRAT significantly promoted the maturation and function of osteoblast by improving the alkaline phosphatase activity, osteocalcin secretion, calcium deposition and the number of mineralized nodular structures. CONCLUSION: The metabolites of TFE should be the anti-osteoporosis constitutes of Epimedium sagittatum.