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Background The purpose of this study was to explore whether moderate-intensity exercise can alleviate motion-induced post-traumatic osteoarthritis (PTOA) and the expression change of lncRNA H19 during this progression. Methods Twenty-week-old male C57BL/6 mice were randomly divided into five groups: model control group (MC group, n = 6), treadmill model group (M group, n = 6), rehabilitation control group (RC group, n = 6), treadmill model + rehabilitation training group (M + R group, n = 6) and treadmill model + convalescent group (M + C group, n = 6). Paraffin sections were used to observe the pathological changes in the mouse knee joint in each group. A micro-CT was used to scan the knee joint to obtain the morphological indexes of the tibial plateau bone. Real-time PCR was used to detect the mRNA levels of inflammatory factors, synthetic and catabolic factors in cartilage. Results After high-intensity exercise for 4 weeks, the inflammation and catabolism of the mouse knee cartilage were enhanced, and the anabolism was weakened. Further study showed that these results were partially reversed after 4-week moderate-intensity training. The results of hematoxylin–eosin staining confirmed this finding. Meanwhile, high-intensity exercise reduced the expression of lncRNA H19 in cartilage, while the expression of lncRNA H19 increased after 4 weeks of moderate-intensity exercise. Conclusion High-intensity treadmill running can cause injury to the knee cartilage in C57BL/6 mice which leads to PTOA and a decrease of lncRNA H19 expression in cartilage. Moderate-intensity exercise can relieve PTOA and partially reverse lncRNA H19 expression.

Osteochondral junction is a functional unit comprising the articular cartilage, calcified cartilage, and subchondral bone. Alteration in any component of this composite unit can disrupt the joint integrity and function directly or indirectly. Biochemical signals mediate the crosstalk between tissues and play an essential role in the initiation and progression of osteoarthritis. As osteoarthritis progresses, abnormal subchondral bone remodelling leads to increased angiogenesis and porosity of the subchondral bone plate, which further triggers biochemical signals to mediate the crosstalk between cartilage and bone, contributing to the progression of osteoarthritis. Notably, common biochemical signals include the TGF-β/Smad, Wnt/β-catenin, RANK/RANKL/OPG, and MAPK pathways. This biomarker crosstalk network is the basis of osteoarthritis pathogenesis, and some of their key regulators may be potential therapeutic targets for osteoarthritis drug therapy. This review summarised the biochemical crosstalk between cartilage and bone in the pathogenesis of osteoarthritis, which may provide the basis for the discovery of osteoarthritis treatment targets.

We have demonstrated 384 × 288 pixels mid-wavelength infrared focal plane arrays (FPA) using type II InAs/GaSb superlattice (T2SL) photodetectors with pitch of 25 μm. Two p-i-n T2SL samples were grown by molecular beam epitaxy with both GaAs-like and InSb-like interface. The diode chips were realized by pixel isolation with both dry etching and wet etching method, and passivation with SiN x layer. The device one with 50% cutoff wavelength of 4.1 μm shows NETD ∼ 18 mK from 77 K to 100 K. The NETD of the other device with 50% cutoff wavelength at 5.6 μm is 10 mK at 77 K. Finally, the T2SL FPA shows high quality imaging capability at the temperature ranging from 80 K to 100 K which demonstrates the devices’ good temperature performance.

A p -type quantum well infrared photodetector (QWIP) integrated with a light-emitting diode (LED) (named QWIP-LED) was fabricated and studied. The infrared photo-response spectrum was obtained from the device resistance variation and the near-infrared photo-emission intensity variation. A good agreement between these two spectra was observed, which demonstrates that the long-wavelength infrared radiation around 7.5 μm has been transferred to the near-infrared light at 0.8 μm by the photo-electronic process in the QWIP-LED structure. Moreover, the experimentally ob-served infrared response wavelength is in good agreement with the theoretical calculation value of 7.7 μm. The results on the upconversion of the infrared radiation will be very useful for the new infrared focal plane array technology.

The effect of intermixing on the THz generation is studied on a quantum well structure excited by a femtosecond pulse laser. An asymmetric coupled GaAs/AlGaAs quantum well is used to enhance the nonlinear effect for THz generation. Our theoretical results indicate that the energy separation between two sublevels, i.e. the frequency of the generated THz radiation, increases with diffusion of the Al component. Then the intensity of the THz emission decreases with diffusion length due to the reduction of nonlinear effect in the quantum well. The intermixing also controls the field at the anticrossing resonance of the two sublevels, at which the THz radiation efficiency will be strongly enhanced. Due to our special design, the resonant field is fixed in the intermixing process. Based on these results, a multi-frequency quantum well chip with emission from 2 to 9 THz may be fabricated by using the technique of selective intermixing.

The electronic structure in p-type δ-doping GaAs is calculated self-consistently by including the contribution of the photogenerated carrier. The theoretical results indicate that the band bending around the δ-doping region is induced by the injection of photogenerated holes into the potential well of the δ-doping GaAs. Moreover the band bending results in two photogenerated carrier-induced wells for electrons. The potential of the two wells is deepened with the increase of the photogenerated carrier density. The photoluminescence (PL) properties are explained in terms of the dependence of the confined electronic states and the Fermi level of the two-dimensional hole gas (2DHG) on the concentration of photogenerated carrier, which is in good agreement with experimental observation of the variation of peak position and intensity with the excitation light intensity.

Considering the disadvantages of STT (Skid-to-Turn) control technology, a kind of ATT (anti-torpedo torpedo) control technique based on BTT (Bank-to-Turn) is proposed. The roll maneuverability mathematics model of ATT is analyzed and predigested necessarily. The roll interference and control equations of ATT are established. Then the roll interference time course and roll angle rapidity are obtained. Finally, the configure method and result of roll control parameters are presented. And the transition curve of two types torpedo is analyzed through ensamples. The result of the research shows that, for the two types torpedo with roll control, the transition course of them is convergent. But, the latter is more appropriate for the demand of roll control system stability of ATT based on BTT, when the roll control parameters are presented in advance.

In order to test and assess the performance of the attitude control system for an Autonomous Underwater Vehicle (AUV) in real time, a test system of semi-physical simulation is designed, based on a test platform with VXI bus. Through a program-controlled rotary estrade, programcontrolled pressure devices, equivalent functional simulating subsystems, some real-time signals are generated accurately, such as the attitudes, velocity and depth of AUV, target angle and trajectory commands. The outputs of the attitude control system are measured in real time so as to find out the control performances of the AUV. The composition principle and simulation-based test scheme of the test system are expatiated. Test and application show that the test system is highly precise and reliable.

GPS-based positioning for AUV is a field of active researches, which integrates DGPS, radio sonobuoy, DSP, high speed data transmission technology with underwater telecommunication technogy. Many problems remain to be solved for GPS application to AUV because of the peculiarity of underwater environment. Some subjects in a GPS-based positioning system for AUV are reviewed in the paper. The development of underwater positioning and underwater GPS technology is introduced first. Secondly, the methods of underwater positioning are analyzed, followed with GPS-based AUV positioning algorithms. Thirdly, the origin of GPS error and its countermeasures are tudied. Finally, a conclusion is drawn that the GPS-based positioning system can provide high precesion positioning for 3D AUV in real time. It is promising in underwater applications. Some key technologies in underwater positioning are presented for future work.