Attitude Determination and Control System Design for STU-2A CubeSat and In-Orbit Results

STU-2A, a 3U CubeSat developed by Shanghai Engineering Center for Microsatellites, along with the other two 2U CubeSats and one MicroSat, has been sent into a 481km sun-synchronous orbit by CZ-11 launch vehicle with its maiden journey. As the first batch of CubeSats in China that is made in accordance with CubeSat standard, the 2.9kg satellite is featured with the on-board CMOS color camera for taking pictures of polar glacier, Gamalink for Cubesats Networking, MEMS based cold-gas micropropulsion for attitude/orbit maneuver and formation flight and precise ADCS module for technology demonstration. The ADCS module, equipped with two 3-axis magnetometers, 1 fine Sun sensor, five coarse Sun sensors, one three-axis MEMS gyro, one Nano-scaled star tracker, three magnetic coils and three reaction wheels, would provide three-axis stabilization and maneuver capability. Combining the attitude sensors, TRAID and unscented Kalman Filter (UKF) algorithms are adopted to determine the attitude knowledge. Some attitude control modes, such as damping control, Sun-pointing, magnetic-based nadir pointing, momentum-biased stabilization and reaction wheels-based control, are designed to achieve the prefect attitude.In-Orbit data received by ground station verified the performance of ADCS of STU-2A

Autophagy protects against palmitate-induced apoptosis in hepatocytes

BACKGROUND: Non-alcoholic fatty liver disease, one of the most common liver diseases, has obtained increasing attention. Palmitate (PA)-induced liver injury is considered a risk factor for the development of non-alcoholic fatty liver disease. Autophagy, a cellular degradative pathway, is an important self-defense mechanism in response to various stresses. In this study, we investigated whether autophagy plays a protective role in the progression of PA-induced hepatocytes injury. RESULTS: Annexin V-FITC/PI staining by FCM analysis, TUNEL assay and the detection of PARP and cleaved caspase3 expression levels demonstrated that PA treatment prominently induced the apoptosis of hepatocytes. Meanwhile, treatment of PA strongly induced the formation of GFP-LC3 dots, the conversion from LC3I to LC3II, the decrease of p62 protein levels and the increase of autophagosomes. These results indicated that PA also induced autophagy activation. Autophagy inhibition through chloroquine pretreatment or Atg5shRNA infection led to the increase of cell apoptosis after PA treatment. Moreover, induction of autophagy by pretreatment with rapamycin resulted in distinct decrease of PA-induced apoptosis. Therefore, autophagy can prevent hepatocytes from PA-induced apoptosis. In the further study, we explored pathway of autophagy activation in PA-treated hepatocytes. We found that PA activated PKCα in hepatocytes, and had no influence on mammalian target of rapamycin and endoplasmic reticulum stress pathways. CONCLUSIONS: These results demonstrated that autophagy plays a protective role in PA-induced hepatocytes apoptosis. And PA might induce autophagy through activating PKCα pathway in hepatocytes

Time-course adaptive changes in hippocampal transcriptome and synaptic function induced by simulated microgravity associated with cognition

IntroductionThe investigation of cognitive function in microgravity, both short-term and long-term, remains largely descriptive. And the underlying mechanisms of the changes over time remain unclear.MethodsBehavioral tests, electrophysiological recording, and RNA sequencing were used to observe differences in behavior, synaptic plasticity, and gene expression.ResultsInitially, we measured the performance of spatial cognition exposed to long-term simulated microgravity (SM). Both working memory and advanced cognitive abilities were enhanced. Somewhat surprisingly, the synaptic plasticity of the hippocampal CA3-CA1 synapse was impaired. To gain insight into the mechanism of changing regularity over time, transcriptome sequencing in the hippocampus was performed. The analysis identified 20 differentially expressed genes (DEGs) in the hippocampus after short-term modeling, 19 of which were up-regulated. Gene Ontology (GO) analysis showed that these up-regulated genes were mainly enriched in synaptic-related processes, such as Stxbp5l and Epha6. This might be related to the enhancement of working memory performance under short-term SM exposure. Under exposure to long-term SM, 7 DEGs were identified in the hippocampus, all of which were up-regulated and related to oxidative stress and metabolism, such as Depp1 and Lrg1. Compensatory effects occurred with increased modeling time.DiscussionTo sum up, our current research indicates that the cognitive function under SM exposure is consistently maintained or potentially even being enhanced over both short and long durations. The underlying mechanisms are intricate and potentially linked to the differential expression of hippocampal-associated genes and alterations in synaptic function, with these effects being time-dependent. The present study will lay the experimental and theoretical foundation of the multi-level mechanism of cognitive function under space flight

Biological Control of the Cucumber Downy Mildew Pathogen <i>Pseudoperonospora cubensis</i>

Cucumber downy mildew (CDM) is a destructive plant disease caused by the air-borne oomycete pathogen Pseudoperonospora cubensis. CDM causes severe yield reduction of cucumber and significant economic losses. Biocontrol is a promising method to control CDM with the advantage of being beneficial to sustainable agricultural development. However, until now, no reviews of biocontrol of CDM have been reported. The objective of this review is to more comprehensively understand the biocontrol of CDM. In this review, the biological characteristics of P. cubensis are introduced, and strategies for screening biocontrol agents to suppress CDM are recommended. Then the current biocontrol agents, including fungi such as Trichoderma and biocontrol bacteria such as Bacillus, which possess the ability to control CDM, and their control characteristics and ability against CDM are also summarized. The potential mechanisms by which these biocontrol agents prevent CDM are discussed. Finally, several suggestions for future research on the biocontrol of CDM are provided

Biological Control of the Cucumber Downy Mildew Pathogen Pseudoperonospora cubensis

Cucumber downy mildew (CDM) is a destructive plant disease caused by the air-borne oomycete pathogen Pseudoperonospora cubensis. CDM causes severe yield reduction of cucumber and significant economic losses. Biocontrol is a promising method to control CDM with the advantage of being beneficial to sustainable agricultural development. However, until now, no reviews of biocontrol of CDM have been reported. The objective of this review is to more comprehensively understand the biocontrol of CDM. In this review, the biological characteristics of P. cubensis are introduced, and strategies for screening biocontrol agents to suppress CDM are recommended. Then the current biocontrol agents, including fungi such as Trichoderma and biocontrol bacteria such as Bacillus, which possess the ability to control CDM, and their control characteristics and ability against CDM are also summarized. The potential mechanisms by which these biocontrol agents prevent CDM are discussed. Finally, several suggestions for future research on the biocontrol of CDM are provided

Gas turbine power calculation method of turboshaft based on simulation and performance model

Gas turbine power of turboshaft engine cannot be measured, a total of five typical steady state point test data from the ground slow state to the maximum state were selected according to the factory acceptance test drive of a certain type of carrier-based helicopter turboshaft engine. Combustion chamber three-dimensional simulation model was established to carry on simulation analysis of different typical steady state combustion process. The simulated combustion chamber exit section parameters are input into the established gas turbine isentropic adiabatic aerodynamic calculation model to obtain the gas turbine power and outlet temperature. Select five typical steady state points of five sets of turboshaft engines on the same type to repeat the above calculation process, and compare the calculated value of gas turbine outlet temperature with the acceptance test values, it is found that the error values are all within 5%, and the effectiveness and accuracy of the gas turbine power calculation method are verified

Convenient and Efficient Fabrication of Colloidal Crystals Based on Solidification-Induced Colloidal Assembly

The simple yet efficient and versatile fabrication of colloidal crystals was investigated based on the solidification-induced colloidal crystallization process with particle/water suspension as precursor. The resulting colloidal crystals were constituted by crystal grains with sizes ranging from several tens of micrometers to a few millimeters. Each of the grains had a close-hexagonal array of colloids, which endowed the bulk colloidal crystal powders with some specific optical properties. The freezing of water was shown as the major driving force to form colloidal crystal grains, which supersaturated the solution with nanoparticles and thus induced the formation and growth of colloidal crystal seeds. This process is intrinsically different from those conventional methods based on shearing force, surface tension, columbic interaction or magnetic interaction, revealing a new strategy to fabricate colloidal crystals in a convenient and efficient way