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The single event effect caused by space heavy ion radiation is one of the important factors affecting the safety and operation of spacecraft on orbit. In the research and evaluation of the frequency, spatial distribution and time characteristics of single event effects, linear energy transfer (LET) spectra of space radiation play an important role. On the Beidou navigation M15 and M16 satellites, a single event upset (SEU) and LET monitor was developed to obtain the upsets of the memory device and the LET spectra of space radiation which passes through the device. Through the measurement results from this monitor, the correlation between the device’s SEUs and the LET spectra could be studied.

The orbit of BeiDou satellite system is a very ideal space environment monitoring area. The radiation dosimeters are present on this series of navigation satellites, and they are respectively installed in the x, y and z positions. A charge detector installed in the satellite cabin is used for monitoring satellite deep charging potential. Radiation dosimeters select the 100 nm P-channel metal oxide semiconductor (PMOS) sensors, whose monitoring range can reach 2 × 106 rad (Si). In the circuit design part, the “zero temperature coefficient” current of the PMOS is used as the constant current source for measuring, which effectively reduces the influence of temperature effect. Three radiation dosimeters realize the daily dose change monitoring during the satellite’s operation, and the detection accuracy is high. The deep charging potential sensor adopts the equivalent capacitor design which is composed of the outer optical quartz glass and the inner circular gold-plate. The two kinds of detection instruments have the characteristics of small volume, low power consumption and high detection accuracy. The detection results show that they have important application value for space environment prediction and guarantee.

This work introduces the instruments’ design of multi-directional medium-energy electron detector (energy range: 30–770 keV) and high-energy electron detector (energy range: 400 keV to 5.8 MeV) deployed on one of the BeiDou navigation satellites in medium earth orbit. Through the electromagnetic compatibility design, the problem of the detector signal being susceptible to electromagnetic interference is solved and the lower detection limit reaches a very low level of 20 keV. The proton contamination in the electron measurement can be effectively removed by designing the light-blocking layer and the logical working mode of the sensors. The detector circuits and sensor structure are optimized and the miniaturization of the instrument is realized. This study also introduces the calibration method of the detectors, and gives the ground test results, which can provide a basis for the on-orbit calibration and data processing of the instrument.

Space radiation particles will cause a variety of radiation effects on orbiting satellites, such as single event effects, total ionizing dose, displacement damage, etc. In response to these space radiation effects, BeiDou Navigation satellites M15/M16 operating in medium earth orbit (MEO) developed the first integrated monitor for high-energy proton and particle radiation effects, based on space particle radiation detection technology. This payload realizes the joint observation of the high-energy proton environment, particle radiation linear energy transfer spectrum, and total radiation dose in the MEO. According to the detection data, research on the characteristics and laws of the space particle radiation effects can be carried out, and the problem of spacecraft reliability verification in orbit can be solved from the causal chain. In this article, we have introduced the high-energy proton detector (energy range 3–300 MeV), including technical indicators, working principles, instrument design, and ground calibration.

The long‐acting sustained‐release of active molecules is of great importance in chemical production, food preservative, drug delivery in vivo, and so on. However, the problems of initial‐burst release and short release time (dominated by Fick's lows) commonly exist in sustained‐release materials. Herein, we designed and fabricated two types of film materials to achieve slow, continuous, and long‐term release of small molecules using methyl orange (MO) as a target release substance. B‐MO@polymer films were obtained by embedding MO into polylactic acid/polyethylene glycol (PLA/PEG) substrate and then assembling a layered double hydroxide (LDH)/carboxymethyl chitosan (CMC) barrier layer on the substrate surface. Another type of film (LDH&MO@polymer) was prepared by blending LDH and MO into the PLA/PEG polymer matrix. These films show high loading capacities of ~500 μg/cm2 for MO and display long‐acting sustained‐release property arising from the barrier effect of LDH nano‐brick. Specifically, for the B‐MO@polymer film, the release time of 50% MO is 10 days and the release time of 80% MO can be extended to 30 days. Ultimately, the time for complete release (>96%) reaches over 60 days. By using LDH‐embedded polymer as carriers for active molecules, the zero‐order release of MO was realized for LDH&MO@polymer films, achieving sustained release within as long as 145 days. This work provides a new paradigm to achieve the long‐acting sustained‐release of active molecules through the barrier effect of 2D nano‐bricks. Highlight: Two types of films were obtained to achieve long‐term release of small molecules.The films show high loading capacities for active molecules.The long‐acting property is derived from the barrier effect of 2D nano‐brick.The films can be produced in a large scale and have good application prospects. [ABSTRACT FROM AUTHOR]

Based on the characteristics of space particle radiation in the Sun-synchronous orbit (SSO), a space particle radiation effect comprehensive measuring instrument (SPRECMI) was installed on the orbital platform of the upper stage of the Chinese CZ-4C carrier rocket, which can acquire the high-energy proton energy spectra, linear energy transfer (LET) spectra of particles, and radiation dose rate. The particle radiation detection data were obtained at 1000 km altitude for the first time, which can be used mainly for scientific research of the space environment, in-orbit fault analysis, and the operational control management of spacecraft, and can also serve as reference data for component validation tests. After SPRECMI's development, accelerator calibration and simulations were conducted, and the results demonstrated that all the measured indicators, including the high-energy proton spectra (energy range: 21.8–275.0 MeV, precision: <3.3%), total radiation dose (dose range: 0–1.04 × 106 rad, sensitivity: 6.2 µrad/h), and the LET spectra (range: 0.001–37.20 MeV/(mg/cm2), >37.2 MeV/(mg/cm2)), met the relevant requirements. Furthermore, the in-orbit flight test revealed that the detection results of the load components were consistent with the physical characteristics of the particle radiation environment of the spacecraft's orbit. [ABSTRACT FROM AUTHOR]

Based on orbit detection data acquired by a positive channel Metal Oxide Semiconductor (PMOS) dose detectors on FY4-A (GEO), BD3-M15 (MEO), and YH1-01A (LEO) between November 2018 and November 2022, investigations reveal variations in total dose and the mechanism of radiation dose increase within the geostationary earth orbit (GEO), medium earth orbit (MEO), and low earth orbit (LEO) during the transition from the 24th to the 25th solar cycles. It provides the radiation dose parameters for the study of the space environment from different altitude orbits, and also provides an important basis for studying the solar minimum activity and dose generation The data indicate directional disparities in radiation doses among the orbital regions, with the hierarchy being FY4-A > YH1-01A > BD3-M15. Furthermore, the results show that the total doses of FY4-A and BD3-M15 were higher than that of YH1-01A by two orders of magnitude, with BD3-M15 > FY4-A > YH1-01A. The monthly radiation dose rates of FY4-A in GEO and BD3-M15 in MEO exhibited positive correlation with their corresponding APs during the solar minimum. Notably, for FY4-A, the monthly radiation dose rate during geomagnetic disturbed periods exceeded that of the dose rate during geomagnetic quiet periods by one order of magnitude. This analysis revealed the substantial impact of geomagnetic storms and space environment disturbances on radiation doses detected by MEO and GEO orbital satellites. These perturbations, attributable to medium- and small-scale high-energy electron storms induced by reproducible coronal holes, emerged as key driving factors of the increase in radiation doses in MEO and GEO environments. [ABSTRACT FROM AUTHOR]

Context: Although it is recognized that thrombin plays a key role in airway remodeling during chronic asthma. In a previous study, we have proved that thrombin promotes airway remodeling via PAR-1 in OVA-allergic rats, but little is known about intracellular signaling pathway involved in the event. Objective: In this study, we intend to explore the impact of pERK1/2 signaling pathway on the process of thrombin-induced airway remodeling in OVA-allergic rats. Materials and methods: A rat model of chronic asthma was set up by systemic sensitization and repeated challenge to OVA. The doses of thrombin, recombinant hirudin, PAR-1 inhibitor ER-112780-06, and pERK1/2 inhibitor PD98059 varied for different groups. The expression of pERK1/2 was analyzed by western blot and RT-PCR. Secretion of TGF-β1 and IL-6 was detected by ELISA. Results: The expression of pERK1/2 was higher in the airway of asthmatic rats than those of normal rats, and was significantly increased by thrombin treatment but decreased by thrombin-inhibitor treatment. Airway remodeling was enhanced by thrombin but weakened by pERK1/2 inhibitor. Expression of growth factors and IL-6 in asthmatic rats was significantly increased by thrombin treatment and decreased by thrombin-inhibitor treatment and pERK1/2 inhibitor treatment. Conclusion: These results suggest that ERK1/2 signaling pathway may play an important role in the process of thrombin-promoting airway remodeling in OVA-allergic rats, and pERK1/2 inhibitor effectively inhibits the process. [ABSTRACT FROM AUTHOR]