Xuping Zhang

BML-111, a lipoxin receptor agonist, modulates the immune response and reduces the severity of collagen-induced arthritis

Abstract.Objective:Lipoxins (LXs) are endogenous antiinflammatory and pro-resolving eicosanoids generated during various inflammatory conditions. Recent research has revealed the novel immunomodulatory function of LXs. The aim of this study is to investigate whether LXs modulate the pathogenesis of collagen-induced arthritis (CIA), a typical chronic immune-mediated inflammatory disease.Methods and results:CIA was induced in DBA/1 mice and BML-111, a lipoxin A4 receptor agonist, was administrated. Results indicated that compared with untreated CIA mice, both clinical disease activity scores and histological destruction of joint were significantly reduced in BML-111-treated CIA mice. The dampened joint injury was accompanied by decreased concentrations of serum pro-inflammatory cytokines tumor necrosis factor α and interleukin-6 in BML-111-treated CIA mice. In addition, proliferation of isolated spleen cells, as well as circulating levels of antibody to type II collagen, were reduced significantly in BML-111-treated CIA mice.Conclusion:BML-111 attenuated CIA in part by negatively regulating the immune response, which implicates the potential pharmacological value of LXs in the treatment of chronic immune-mediated inflammatory diseases such as RA.

Effect of tacrolimus and cyclosporine A on suppression of albumin secretion induced by inflammatory cytokines in cultured human hepatocytes.

Abstract.Objective and designTo investigate the effect of tacrolimus (FK506) and cyclosporine A (CSA) on albumin secretion and on the IL-6 -induced suppression of albumin synthesis in cultured human hepatocytes.MethodsHepG2 cells were cultured separately with IL-6, IL-10 (0–10xa0ng/ml) and FK506, CSA (0–100xa0ng/ml) for 48xa0h. In another experiment, HepG2 cells were incubated with different amounts of FK506 and CSA (0–10xa0ng/ml) in the presence of IL-6 (5xa0ng/ml). The albumin levels in these groups of hepatic cultures were measured by radioimmunoassay. The concentration of LDH secreted by cells stimulated with FK506 and CSA was detected by spectrophotometry.ResultsIL-6 decreased the levels of albumin in a dose-dependent manner (Pxa0xa0<xa0xa00.01), maximal inhibition was observed at 5xa0ng/ml. Neither IL-10 nor FK506 modulated albumin production. However, FK506 decreased LDH levels in the supernatant of cells (Pxa0xa0<xa0xa00.05) and prevented the IL-6-induced suppression of albumin synthesis (Pxa0xa0<xa0xa00.01) in a dose dependent manner. In contrast, CSA caused only a slight decrease in albumin levels (Pxa0xa0<xa0xa00.05). In addition, CSA slightly increased the amount of LDH in HepG2 cells and did not interfere with the IL-6-induced decrease in albumin synthesis.ConclusionsThese findings suggest that IL-6, but not IL- 10, may play an important role in the suppression of hepatic albumin secretion. FK506 but not CSA protects against the suppression of hepatic albumin synthesis caused by IL-6.

An event recognition method for fiber distributed acoustic sensing systems based on the combination of MFCC and CNN

Fiber distributed acoustic sensing (FDAS) systems have been widely used in many fields such as oil and gas pipeline monitoring, urban safety monitoring, and perimeter security. An event recognition method for fiber distributed acoustic sensing (FDAS) systems is proposed in this paper. The Mel-frequency cepstrum coefficients (MFCC) of the acoustic signals collected by the FDAS system are computed as the features of the events, which are inputted into a convolutional neural network (CNN) to determine the type of the events. Experimental results based on 2300 training samples and 946 test samples show that the precision, recall, and f1-score of the classification model reach as high as 98.02%, 97.99%, and 97.98% respectively, which means that the combination of MFCC and CNN may be a promising event recognition method for FDAS systems.

Localization and Discrimination of the Perturbation Signals in Fiber Distributed Acoustic Sensing Systems Using Spatial Average Kurtosis

Location error and false alarm are noticeable problems in fiber distributed acoustic sensing systems based on phase-sensitive optical time-domain reflectometry (Φ-OTDR). A novel method based on signal kurtosis is proposed to locate and discriminate perturbations in Φ-OTDR systems. The spatial kurtosis (SK) along the fiber is firstly obtained by calculating the kurtosis of acoustic signals at each position of the fiber in a short time period. After the moving average on the spatial dimension, the spatial average kurtosis (SAK) is then obtained, whose peak can accurately locate the center of the vibration segment. By comparing the SAK value with a certain threshold, we may to some degree discriminate the instantaneous destructive perturbations from the system noise and certain ambient environmental interferences. The experimental results show that, comparing with the average of the previous localization methods, the SAK method improves the pencil-break and digging locating signal-to-noise ratio (SNR) by 16.6 dB and 17.3 dB, respectively; and decreases the location standard deviation by 7.3 m and 9.1 m, respectively. For the instantaneous destructive perturbation (pencil-break and digging) detection, the false alarm rate can be as low as 1.02%, while the detection probability is maintained as high as 95.57%. In addition, the time consumption of the SAK method is adequate for a real-time Φ-OTDR system.

Environmental parameters monitoring using a single mode-bare core multimode-single mode optical fiber sensor

We report a single mode-bare core multimode-single mode (SBMS) optical fiber sensor, for environmental parameters in-situ monitoring. Compared with the reflection structure and the transmission structure of the SBMS optical fiber sensors, we found that the repeatability and stability results of the reflection structure were much better than that of the transmission structure’s. The principle of this experimental design is based on the optical fiber which can be transmitted by the outside temperature modulation. Because the parameters of the light transmitted in the single mode-multimode single mode (SMS) fiber structure are subject to the change of the external physical factors, this type of fiber optic temperature sensor is made by multiple modes of transmission in a multimode fiber. As the light source transmits a distance in the multimode fiber, it will change greatly, making the input light and the final output light produce a great difference. While the length of the bare core multimode fiber was around 8.1cm, the temperature cross-sensitivity of the device had good linearity and was around 0.009075nm/°C , from 50 °C to 350 °C. Furthermore, the increased temperature curve was almost coincided with the decreased temperature curve.

Precise sample preconcentration based on plasmon-assisted optical manipulation for a bead-based Raman biosensor

We developed a novel lab-on-a-chip device with the capability of rapidly pre-concentrating for Raman detection that use gold bead as the solid carrier of biomolecules. The device combines an array of patterned plasmonic surface (i.e. gold nano-ellipses), as the bead manipulation element. The purpose of gold bead manipulation is to provide sample pre-concentration in close proximity of the Raman detecting region. In the presence of an external uniform electric field, the gold ellipses create local electric field gradients (which is usually called hot spots) that capture the gold beads. The location of hot spots within a plasmonic nanostructure is polarization dependent, and inhomogeneous electric field between two adjacent nano-ellipses perpendicular to each other leads to highly unbalanced trap potential that give the chance of transferring trapped particles in a given direction through rotating the polarization. Nano-optical conveyor belts with staircase pattern of nano-ellipses were arranged with their terminus collected at detection area to gather biomolecules. With the capacity to transfer biomolecules precisely, our design offers an attractive scheme for rapid, high throughput and highly sensitive sensing of low abundance analytes.

Radiation resilient fiber Bragg grating sensors for sensing applications in nuclear reactor cores

This paper reports testing results of radiation resilient fiber Bragg grating (FBG) in radiation resistant fibers in the nuclear reactor core at MIT Research Reactor Lab. FBGs were fabricated by 140-fs ultrafast laser pulse using a phase mask approach. In-core test of fiber Bragg gratings was carried out in the core region of a 6-MW research reactor at temperature > 600°C and an average fast neutron (>1 MeV) flux >1×1014 n/s/cm2. First 100-day tests of FBG sensors shows less than 5 dB reduction in FBG peak strength after over 1×1020 n/cm2 of accumulated fast neutron dosage. To test temporal responses of FBG sensors, a number of reactor anomaly events were artificially created to abruptly change reactor power, temperature, and neutron flux over short periods of time. The thermal optical coefficients and temporal responses of FBG sensors are determined at different accumulated dosages of neutron flux. Results presented in this paper reveals that temperature-stable Type-II FBGs fabricated in radiation-hardened fibers could be used as sensors to perform in-pile measurements to improve safety and efficiency of existing and next generation nuclear reactors.

Monitoring and warning system of slope based on distributed fiber optic sensor technology

This paper illustrates the principle of several common distributed fiber sensing techniques, especially Brillouin optical time domain reflectometry (BOTDR) and optical time domain reflectometry (OTDR). By measuring the frequency shift of spontaneous Brillouin scattering light in fiber, BOTDR could simultaneously monitor both strain and temperature with a high spatial resolution. But the spontaneous Brillouin scattering signal is so weak that it has a high demand of the laser generator and the signal-to-noise ratio of the whole system. Therefore, the BOTDR system is usually too complex, expensive and difficult to be widely used. Unlike BOTDR, OTDR utilizes Rayleigh scattering to measure the loss of fiber. Rayleigh scattering signal is much stronger than spontaneous Brillouin scattering signal, thus OTDR system has the advantages of high sensitivity, long distance and relatively low price. These advantages make OTDR very suitable for wide application in the field of slope monitoring, especially in remote areas where the geographical environment is complex and are difficult for staff to stay. This paper designed and implemented a slope monitoring and warning system based on the technology of optical time domain reflectometry(OTDR). The test result shows that the system has high sensitivity, strong real-time and provides user friendly interface.

Study on the characteristics of microfluidic oscillator based on a new type of normally closed valve structure

This article introduced a new type of normally closed micro-valve (NCV) equipped with curved channels and trapezia-shaped valve seat, which could solve the issues of large area of dead zone, high threshold pressure and slow response speed of NCV in the current microfluidic oscillators. The new type of NCV has a three-layered structure with a top controlling layer, medium membrane layer and the bottom feedback layer. The membrane channel in the feedback layer is specifically deigned as curved to decrease the dead zone area. The valve seat is designed as a trapezoid to reduce the adhesion between the membrane and the valve seat and the threshold pressure of the NCV , and to improve the response speed of the system .The results of simulation study on COMSOL shows that this micro-valve structure reduces the NCV threshold pressure by 45% and the oscillation period of the micro-oscillator by 36%. This article conducted further simulation studies on the factors that influence the oscillation period of micro-oscillator. When enlarging inlet flow rate of micro-oscillator, lowering NCV threshold pressure and decreasing valve seat angle, the oscillation period would be reduced. Otherwise, the oscillation period will be increased.

Sensing with slow light in an active fiber Bragg grating

The phase-shifted sensitivity of an interferometer can be enhanced by increasing the group index. In this paper, we experimentally demonstrate a slow light sensor by placing an active fiber Bragg grating (FBG) in one arm of the Michelson’s interferometer. A 25 KHz AC voltage was applied to a piezoelectric (PZT) set nearby the active FBG. Once the wavelength is varied to near the FBG band edge, the maximum phase-shifted amplitude appears, which is about 1.8 rad and is 4 times greater than that when wavelength is near the center of the reflection band. The active FBG is pumped by a 980 nm laser diode, which can help us to stabilize the system works in the slow light regime to obtain the maximum phase shift. It provides a very simple approach to increase the phase-shifted sensitivity, which is likely to have important applications for strain and acoustic sensors.