Attitude and heading measurement based on adaptive complementary Kalman filter for PS/MIMU integrated system.

The bionic polarization sensor (PS)/MEMS inertial measurement unit (MIMU) integrated system can provide reliable attitude and heading information for unmanned vehicles in the case of GNSS rejection. However, the existing measurement methods have poor adaptability to inclining, sheltering, and other harsh environments, and do not make full use of the complementary characteristics of the gyroscopes, accelerometers, and PS, which seriously affects the system performance. Therefore, this paper proposes an attitude and heading measurement method based on an adaptive complementary Kalman filter (ACKF), which corrects the gyroscopes according to the gravity measured by the accelerometers to improve the attitude accuracy and fuses the IMU heading and tilt-compensated polarization heading by Kalman optimal estimation. On this basis, the maximum correlation entropy of the measured gravity and the theoretical gravity is used to construct an adaptive factor to realize the adaptive complementary of the gyroscopes and the accelerometers. Finally, the effectiveness of the method is verified by the outdoor rotation test without occlusion and the vehicle test with occlusion. Compared with the traditional Kalman filter, the pitch, roll, and heading RMSE of the vehicle test are reduced by 89.3%, 93.2% and, 9.6% respectively, which verifies the great advantages.

Investigation and Optimization of a Line-Locked Quartz Enhanced Spectrophone for Rapid Carbon Dioxide Measurement.

We have developed a rapid quartz enhanced spectrophone for carbon dioxide (CO2) measurement, in which the laser wavelength was tightly locked to a CO2 absorption line and a custom quartz tuning fork (QTF) operating at 12.5 kHz was employed. The intrinsic QTF oscillation-limited response time, as well as the optimal feedback interval, was experimentally investigated. By tightly locking the laser to the R(16) transition of CO2, we obtained a stable laser operation with its center wavelength variation kept within 0.0002 cm-1, merely three times the laser linewidth. The reported CO2 sensor achieved a detection limit of 7 ppm, corresponding to a normalized noise equivalent absorption coefficient (NNEA) of 4.7 × 10-9 W·cm-1·Hz-1/2, at a response time of 0.5 s. The detection limit can be further improved to 0.45 ppm at an integration time of 270 s, illustrating a good system stability. This spectrophone enables the realization of compact and fast-response gas sensors for many scenarios, where CO2 concentration from sub-ppm to hundreds of thousands of ppm is expected.

A Robust Optical Sensor for Remote Multi-Species Detection Combining Frequency-Division Multiplexing and Normalized Wavelength Modulation Spectroscopy.

By combining frequency-division multiplexing and normalized wavelength modulation spectroscopy, a robust remote multi-species sensor was developed and demonstrated for practical hydrocarbon monitoring. Independently modulated laser beams are combined to simultaneously interrogate different gas samples using an open-ended centimeter-size multipass cell. Gas species of interest are demodulated with the second harmonics to enhance sensitivity, and high immunity to laser power variation is achieved by normalizing to the corresponding first harmonics. Performance of the optical sensor was experimentally evaluated using methane (CH4) and acetylene (C2H2) samples, which were separated by a 3-km fiber cable from the laser source. Sub-ppm sensitivity with 1-s time resolution was achieved for both gas species. Moreover, even with large laser intensity fluctuations ranging from 0 to 6 dB, the noise can be kept within 1.38 times as much as that of a stable intensity case. The reported spectroscopic technique would provide a promising optical sensor for remote monitoring of multi hazardous gases with high robustness.

Rosbin, a synthetic small molecule, induces A549 cells apoptosis through a ROS-mediated pathway.

Rosbin (Thieno [2, 3-c] piperidine-3-carboxamide-2-[(3-methoxy-naphtha-lene-2-carbonyl)-amino]-6-(benzyl)-, hydrochloride), a synthetic piperidinothieno derivative compound obtained from chemical genetics screenings, significantly suppresses the viability of non-small cell lung cancer A549 cells with an IC50 of 2.05 ± 0.31 µM. It only decreases growth of non-tumour MRC-5 cells at the doses higher than 10 µM. Rosbin induces apoptosis in a dose-dependent manner by reducing the mitochondrial membrane potential (MMP) and increasing activities of caspases-3/7 and caspase-9 in A549 cells, without affecting the activity of caspase-8. Further studies showed that reactive oxygen species (ROS) induced apoptosis of A549 in the presence of rosbin as apoptosis was inhibited by N-acetyl cysteine (NAC). These results suggest that rosbin is a novel apoptosis inducer, and ROS played a significant role in the A549 apoptosis induced by rosbin.

A novel small molecule, Rosline, inhibits growth and induces caspase-dependent apoptosis in human lung cancer cells A549 through a reactive oxygen species-dependent mechanism.

Chemical screening using synthetic small molecule libraries has provided a huge amount of novel active molecules. It generates lead compound for drug development and brings focus on molecules for mechanistic investigations on many otherwise intangible biological processes. In this study, using non-small cell lung cancer cell A549 to screen against a structurally novel and diverse synthetic small molecule library of 2,400 compounds, we identified a molecule named rosline that has strong anti-proliferation activity on A549 cells with a 50% cell growth inhibitory concentration (IC50 ) of 2.87 ± 0.39 µM. We showed that rosline treatment increased the number of Annexin V-positive staining cell, as well as G2/M arrest in their cell cycle progression. Further, we have demonstrated that rosline induces a decrease of mitochondrial membrane potential (Δφm ) and an increase of caspases 3/7 and 9 activities in A549 cells, although having no effect on the activity of caspase 8. Moreover, we found that rosline could induce the production of reactive oxygen species (ROS) and inhibit the phosphorylation of signaling molecule Akt in A549 cells. Alternatively, an antioxidant N-acetyl-L-cysteine (NAC) significantly attenuated rosline's effects on the mitochondrial membrane potential, caspases 3/7 and 9 activities, cell viabilities and the phosphorylation of Akt. Our results demonstrated that ROS played an important role in the apoptosis of A549 cells induced by rosline.

Folic-Acid-Targeted Self-Assembling Supramolecular Carrier for Gene Delivery.

A targeting gene carrier for cancer-specific delivery was successfully developed through a "multilayer bricks-mortar" strategy. The gene carrier was composed of adamantane-functionalized folic acid (FA-AD), an adamantane-functionalized poly(ethylene glycol) derivative (PEG-AD), and ß-cyclodextrin-grafted low-molecular-weight branched polyethylenimine (PEI-CD). Carriers produced by two different self-assembly schemes, involving either precomplexation of the PEI-CD with the FA-AD and PEG-AD before pDNA condensation (Method A) or pDNA condensation with the PEI-CD prior to addition of the FA-AD and PEG-AD to engage host-guest complexation (Method B) were investigated for their ability to compact pDNA into nanoparticles. Cell viability studies show that the material produced by the Method A assembly scheme has lower cytotoxicity than branched PEI 25 kDa (PEI-25KD) and that the transfection efficiency is maintained. These findings suggest that the gene carrier, based on multivalent host-guest interactions, could be an effective, targeted, and low-toxicity carrier for delivering nucleic acid to target cells.