In order to solve the problems of difficult test, high cost and long cycle in the development of large-scale airborne negative pressure isolation system, the simulation analysis of negative pressure response characteristics is carried out around various aviation conditions such as aircraft ascending, leveling and descending, especially rapid decompression, based on the computational fluid dynamics (CFD) method. The results showed that the isolation cabin could achieve -50 Pa pressure difference environment and form a certain pressure gradient. The exhaust air volume reached the maximum value in the early stage of the aircraft's ascent, and gradually decreased with the increase of altitude until it was level flying. In the process of aircraft descent, the exhaust fan could theoretically maintain a pressure difference far below -50 Pa without working; Under the special condition of rapid pressure loss, it was difficult to deal with the rapid change of low pressure only by the exhaust fan, so it was necessary to design safety valve and other anti-leakage measures in the isolation cabin structure. Therefore, the initial stage of aircraft ascent is the key stage for the adjustment and control of the negative pressure isolation system. By controlling the exhaust air volume and adjusting parameters, it can adapt to the change of low pressure under normal flight conditions, form a relatively stable negative pressure environment, and meet the needs of biological control, isolation and transport.
Aircraft ; Computer Simulation ; Aviation/instrumentation* ; Humans ; Hydrodynamics ; Air Pressure ; Equipment Design ; Pressure

OBJECTIVE To study the mechanism of Wenshen Tongdu Recipe in promoting the recovery of motor function in rats with spinal cord injury.METHODS A total of 144 SD rats were randomly divided into sham operation group,model group,predni-sone group,low-dose Wenshen Tongdu Recipe group,medium-dose Wenshen Tongdu Recipe group,high-dose Wenshen Tongdu Recipe group,3BDO group,and 3BDO+Wenshen Tongdu Recipe group(medium dose).The rat spinal cord injury model was estab-lished by modified Allen's method.Intervention began 1 day after modeling,and the drug was administered continuously for 14 days.During the drug administration period,the motor function of the rats in each group was evaluated by Basso-Beattie-Bresnahan(BBB)score and inclined plane test.On the 3rd,7th and 14th days after modeling,the pathological changes of the spinal cord tissues of the rats in each group were observed by HE staining;the expression levels of inflammatory factors IL-1β,IL-6,IL-4 and IL-10 in the serum of the rats in each group were detected by ELISA;the expression of Beclin 1,LC3B and p62 proteins was detected by immu-nohistochemistry;the expression of CD16 and CD206 proteins was detected by immunofluorescence staining;the expression of autoph-agy-related molecules(Beclin 1,LC3B)and Akt/mTOR pathway-related proteins in the spinal cord tissues was detected by Western blot.RESULTS Compared with the model group,the BBB score and angle of the inclined board test of rats in the medium-dose Wenshen Tongdu Recipe group were increased,and the disordered arrangement of spinal cord tissue,spinal cord vacuoles and inflam-matory infiltration were significantly improved,especially on the 14th day.Compared with the sham operation group,the expression levels of serum IL-1β and IL-6 in the model group increased(P<0.01),and the expression levels of IL-4 and IL-10 decreased(P<0.05,P<0.01);compared with the model group,the levels of IL-1β and IL-6 in the Wenshen Tongdu Recipe group were signifi-cantly decreased(P<0.01),and the levels of IL-4 and IL-10 were significantly increased(P<0.05,P<0.01);compared with the Wenshen Tongdu Recipe group,the serum IL-1β and IL-6 concentrations of mice in the 3BDO group increased(P<0.01),and the level of IL-10 decreased(P<0.05).Compared with the sham operation group,the M1/M2 ratio,P62 protein expression,p-Akt/Akt and p-mTOR/mTOR ratios in the spinal cord tissue of the rats in the model group were significantly increased(P<0.05,P<0.01),and the relative protein expression of Beclin1 was decreased(P<0.01);compared with the model group,the M1/M2 ratio,p-Akt/Akt and p-p70S6K/p70S6K ratios in the Wenshen Tongdu Recipe group were significantly decreased(P<0.01).Compared with the model group,the Beclin1 protein level in the 3BDO group was decreased,and the p-Akt/Akt and p-mTOR/mTOR ratios were increased(P<0.05,P<0.01).Compared with the Wenshen Tongdu Recipe group,the M1/M2 ratio in the 3BDO group and the 3BDO+Wen-shen Tongdu Recipe group increased(P<0.01),the positive rates of Beclin1 and LC3B proteins in the 3BDO group decreased signifi-cantly(P<0.01),and the p-p70S6K/p70S6K ratio in the 3BDO+Wenshen Tongdu Recipe group increased significantly(P<0.01).CONCLUSION Wenshen Tongdu Recipe may regulate microglial polarization through Akt/mTOR signaling pathway to acti-vate autophagy,promote the secretion of anti-inflammatory factors,reduce the release of pro-inflammatory factors,alleviate neuroin-flammatory response,and thus promote spinal cord injury repair.

BACKGROUND:Bone relies on the close connection between blood vessels and bone cells to maintain its integrity.Bones are in a physiologically hypoxic environment.Therefore,the study of angiogenesis and osteogenesis in hypoxic environment is closer to the microenvironment in vivo. OBJECTIVE:To explore the influence of Wenshen Tongluo Zhitong(WSTLZT)formula on H-type bone microvascular endothelial cell/bone marrow mesenchymal stem cell co-culture system in hypoxia environment and its related mechanism. METHODS:Enzyme digestion method and flow sorting technique were used to isolate and identify H-type bone microvascular endothelial cells.Mouse bone marrow mesenchymal stem cells were isolated and obtained by bone marrow adhesion method.H-type bone microvascular endothelial cell/bone marrow mesenchymal stem cell hypoxic co-culture system was established using Transwell chamber and anoxic culture workstation.WSTLZT formula powder was used to intervene in each group at a mass concentration of 50 and 100 μg/mL.The angiogenic function of H-type bone microvascular endothelial cells in the co-culture system was evaluated by scratch migration test and tube formation test.The osteogenic differentiation ability of bone marrow mesenchymal stem cells in the co-cultured system was evaluated by alkaline phosphatase staining and alizarin red staining.The protein and mRNA expression changes of PDGF/PI3K/AKT signal axis related molecules in H-type bone microvascular endothelial cells in the co-cultured system were detected by Western Blotting and q-PCR,respectively. RESULTS AND CONCLUSION:(1)Compared with the normal oxygen group,the scratch mobility and new blood vessel length of H-type bone microvascular endothelial cells were significantly higher(P<0.05);the osteogenic differentiation capacity of bone marrow mesenchymal stem cells was higher(P<0.05);the expression of PDGF/PI3K/AKT axis-related molecular protein and mRNA increased(P<0.05)in the hypoxia group.(2)Compared with the hypoxia group,scratch mobility and new blood vessel length were significantly increased in the H-type bone microvascular endothelial cells(P<0.05);bone marrow mesenchymal stem cells had stronger osteogenic function(P<0.05);the expression of PDGF/PI3K/AKT axis-related molecular proteins and mRNA further increased(P<0.05)after treatment with different dose concentrations of WSTLZT formula.These findings conclude that H-type angiogenesis and osteogenesis under hypoxia may be related to the PDGF/PI3K/AKT signaling axis,and WSTLZT formula may promote H-type vasculo-dependent bone formation by activating the PDGF/PI3K/AKT signaling axis,thereby preventing and treating osteoporosis.

OBJECTIVE To study the mechanism of Wenshen Tongdu Recipe in promoting the recovery of motor function in rats with spinal cord injury.METHODS A total of 144 SD rats were randomly divided into sham operation group,model group,predni-sone group,low-dose Wenshen Tongdu Recipe group,medium-dose Wenshen Tongdu Recipe group,high-dose Wenshen Tongdu Recipe group,3BDO group,and 3BDO+Wenshen Tongdu Recipe group(medium dose).The rat spinal cord injury model was estab-lished by modified Allen's method.Intervention began 1 day after modeling,and the drug was administered continuously for 14 days.During the drug administration period,the motor function of the rats in each group was evaluated by Basso-Beattie-Bresnahan(BBB)score and inclined plane test.On the 3rd,7th and 14th days after modeling,the pathological changes of the spinal cord tissues of the rats in each group were observed by HE staining;the expression levels of inflammatory factors IL-1β,IL-6,IL-4 and IL-10 in the serum of the rats in each group were detected by ELISA;the expression of Beclin 1,LC3B and p62 proteins was detected by immu-nohistochemistry;the expression of CD16 and CD206 proteins was detected by immunofluorescence staining;the expression of autoph-agy-related molecules(Beclin 1,LC3B)and Akt/mTOR pathway-related proteins in the spinal cord tissues was detected by Western blot.RESULTS Compared with the model group,the BBB score and angle of the inclined board test of rats in the medium-dose Wenshen Tongdu Recipe group were increased,and the disordered arrangement of spinal cord tissue,spinal cord vacuoles and inflam-matory infiltration were significantly improved,especially on the 14th day.Compared with the sham operation group,the expression levels of serum IL-1β and IL-6 in the model group increased(P<0.01),and the expression levels of IL-4 and IL-10 decreased(P<0.05,P<0.01);compared with the model group,the levels of IL-1β and IL-6 in the Wenshen Tongdu Recipe group were signifi-cantly decreased(P<0.01),and the levels of IL-4 and IL-10 were significantly increased(P<0.05,P<0.01);compared with the Wenshen Tongdu Recipe group,the serum IL-1β and IL-6 concentrations of mice in the 3BDO group increased(P<0.01),and the level of IL-10 decreased(P<0.05).Compared with the sham operation group,the M1/M2 ratio,P62 protein expression,p-Akt/Akt and p-mTOR/mTOR ratios in the spinal cord tissue of the rats in the model group were significantly increased(P<0.05,P<0.01),and the relative protein expression of Beclin1 was decreased(P<0.01);compared with the model group,the M1/M2 ratio,p-Akt/Akt and p-p70S6K/p70S6K ratios in the Wenshen Tongdu Recipe group were significantly decreased(P<0.01).Compared with the model group,the Beclin1 protein level in the 3BDO group was decreased,and the p-Akt/Akt and p-mTOR/mTOR ratios were increased(P<0.05,P<0.01).Compared with the Wenshen Tongdu Recipe group,the M1/M2 ratio in the 3BDO group and the 3BDO+Wen-shen Tongdu Recipe group increased(P<0.01),the positive rates of Beclin1 and LC3B proteins in the 3BDO group decreased signifi-cantly(P<0.01),and the p-p70S6K/p70S6K ratio in the 3BDO+Wenshen Tongdu Recipe group increased significantly(P<0.01).CONCLUSION Wenshen Tongdu Recipe may regulate microglial polarization through Akt/mTOR signaling pathway to acti-vate autophagy,promote the secretion of anti-inflammatory factors,reduce the release of pro-inflammatory factors,alleviate neuroin-flammatory response,and thus promote spinal cord injury repair.

In order to detect the environmental data of isolated cabin under various environmental conditions,a negative pressure cabin environment detector for aviation was developed,which was composed of a shell,a differential pressure transmitter,a pressure sensor,a carbon dioxide concentration sensor,an oxygen concentration sensor,a temperature and humidity sensor,a data processing module,a liquid crystal display(LCD)screen and USB data interface.It could environmental data such as carbon dioxide concentration,oxygen concentration,temperature,humidity,pressure difference between cabin and outside the cabin and air pressure outside the cabin in real time,the data processing module collected and processed the data,the data and data change curves was displayed in real time by the LCD screen,and the detection data was extracted through the USB data interface.When used in aviation environment,the detector could work continuously without fault for no less than 300 hours,and the average fault repair time was about 30 minutes,with good performance and high detection accuracy,which can provide convenience for the environmental data detection of negative pressure cabins,and is worthy of popularization.

OBJECTIVE To study the intervention effects of Wenshen Tongluo Zhitong Recipe(WTZR)on macrophage senes-cence and senile osteoporosis.METHODS The senescent macrophage model was established using hydrogen peroxide(H2 O2)and subsequently divided into four groups:control,model,low-dose drug-treated serum,and high-dose drug-treated serum.β-galactosidase staining,Western blot and qPCR were employed to evaluate the mRNA expression of senescence markers p21 and p53.ROS staining and JC-1 staining were applied to assess mitochondrial function in macrophages.The mRNA levels of Interleukin(IL)-6,IL-10,CD206,and inducible nitric oxide synthase(iNOS)were determined by qPCR analysis.Immunofluorescence was used to evaluate argi-nase(ARG1)and iNOS protein expressions for assessing the impact of drug-containing serum on macrophage polarization.qPCR analy-sis was conducted to measure osteocalcin(OCN),collagen type Ⅰ alpha 1(Col1a1),runt-related transcription factor 2(Runx2)mRNA levels as osteoblast-related markers;ALP staining along with alizarin red staining were performed to evaluate the effect of macrophage conditioned medium treated with drug-containing serum on bone marrow mesenchymal stromal cell(BMSC)osteogenic differentiation.C57BL/6J mice were randomly allocated into four groups:control group,model group,WTZR low-dose group,and WTZR high-dose group.The senile osteoporosis(SOP)mouse model was established by D-galactose.Micro-CT scanning analyzed fe-mur microstructure while HE staining detected pathological changes in femur bone tissue samples collected from each experimental con-dition.Furthermore,Western blot was used to detect the senescence-related molecules p21 and p53 and the osteogenesis-related mark-ers OCN and Runx2,qPCR analysis measured tibial expression levels of senescence-related molecules(p21,p53)as well as macro-phage polarisation-related molecules(IL-6,iNOS,CD206,and IL-10)to assess the effect of this compound on a mouse model simula-ting SOP.RESULTS Following intervention with serum containing WTZR,there was a significant decrease in the number of senes-cent positive cells compared to the model group.Additionally,there was a notable decrease in p21 and p53 mRNA and proteins expres-sion(P＜0.05,P＜0.01,P＜0.001).Furthermore,drug-containing WTZR effectively inhibited ROS production induced by H2 O2 and mitigated mitochondrial membrane potential reduction in macrophages(P＜0.05,P＜0.001).Treatment with drug-containing WTZR re-sulted in down-regulated mRNA expression of M1-related gene iNOS(P＜0.05)while up-regulating mRNA expression of M2-related genes CD163 and CD206(P＜0.05).The drug-containing WTZR significantly reduced fluorescence intensity for iNOS(P＜0.01)while increasing ARG1(P＜0.05)fluorescence intensity.Moreover,conditioned medium from macrophages treated with drug-containing ser-um increased ALP positive cell count(P＜0.01,P＜0.001),alizarin red positive area(P＜0.05),as well as Col1a1,Runx2 and OCN mRNA expression levels(P＜0.05,P＜0.01).The Tb.N,BMD,and BV/TV were significantly higher in the WTZR group compared to the model group(P＜0.05,P＜0.01,P＜0.001);meanwhile,Tb.Sp was notably lower than that observed in the model group(P＜0.05,P＜0.01);bone trabeculae were significantly improved,increased in number and widened.Additionally,the compound could significantly inhibit the D-galactose induced up-regulation of tibial senescence-related genes and proteins p21 and p53(P＜0.05,P＜0.001,P＜0.0001),promote the expression of osteogenesis-related markers OCN and Runx2 protein(P＜0.01,P＜0.0001),promote the down-regulation of M1 related genes IL-6 and iNOS(P＜0.05),and promote the expression of M2 related genes IL-10 and CD206(P＜0.05,P＜0.01).CONCLUSION Wenshen Tongluo Zhitong Recipe may play an anti-osteoporosis effect by inhibiting macrophage senescence and promoting the osteogenic differentiation of BMSC.

Objective To analyze and discuss the status of fighter pilots' centrifuge training,to investigate the pilots' G tolerance and to provide reference for training program improvement.Methods One thousand and one hundred ninety-nine fighter pilots' human centrifuge training data were collected and analyzed by cross-sectional study.Pilots were classified by the training purposes that were for aeromedical qualification and competitive assessment.The up-to-standard rates were compared upon the analysis of pilots' training performance.Results In 877 pilots for aeromedical qualification,594 completed the runs of 8 G for 10 s,106 completed 9 G for 10 s.The qualification rate was 79.1％.In 180 high performance fighter pilots selected for competitive assessment,141 completed the runs of 9 G for 10 s.The qualification rate was 78.3％.In 142 second generation fighter pilots selected for competitive assessment,140 completed the runs of 7 G for 10 s.The qualification rate was 98.6％ which was significantly greater than that of the pilots for aeromedical qualification (x 2 =31.141,P ＜ 0.01) and high performance fighter pilots selected for competitive assessment (x 2 =29.318,P＜0.01).There was no difference on qualification rate between the latter two groups (x2 =0.058,P ＞0.05).The incidence of G-LOC and A-LOC was 5.0％ and 2.7％ respectively.The incidences of G-LOC (x2 =4.983,P＜0.05) and A-LOC (x2 =7.528,P＜0.05) of the pilots selected for competitive assessment were significantly greater than those of the pilots for aeromedical qualification.In 1 199 pilots,only 2 pilots (0.17％) had severe acute lumbar sprain.Conclusions Advanced anti-G methods have been adopted in our centrifuge training.The incidences of G-LOC and spinal injury induced by centrifuge training are low.The training program still needs further development and the training effectiveness should be improved.

Objective To analyze and discuss the status of fighter pilots' centrifuge training,to investigate the pilots' G tolerance and to provide reference for training program improvement.Methods One thousand and one hundred ninety-nine fighter pilots' human centrifuge training data were collected and analyzed by cross-sectional study.Pilots were classified by the training purposes that were for aeromedical qualification and competitive assessment.The up-to-standard rates were compared upon the analysis of pilots' training performance.Results In 877 pilots for aeromedical qualification,594 completed the runs of 8 G for 10 s,106 completed 9 G for 10 s.The qualification rate was 79.1％.In 180 high performance fighter pilots selected for competitive assessment,141 completed the runs of 9 G for 10 s.The qualification rate was 78.3％.In 142 second generation fighter pilots selected for competitive assessment,140 completed the runs of 7 G for 10 s.The qualification rate was 98.6％ which was significantly greater than that of the pilots for aeromedical qualification (x 2 =31.141,P ＜ 0.01) and high performance fighter pilots selected for competitive assessment (x 2 =29.318,P＜0.01).There was no difference on qualification rate between the latter two groups (x2 =0.058,P ＞0.05).The incidence of G-LOC and A-LOC was 5.0％ and 2.7％ respectively.The incidences of G-LOC (x2 =4.983,P＜0.05) and A-LOC (x2 =7.528,P＜0.05) of the pilots selected for competitive assessment were significantly greater than those of the pilots for aeromedical qualification.In 1 199 pilots,only 2 pilots (0.17％) had severe acute lumbar sprain.Conclusions Advanced anti-G methods have been adopted in our centrifuge training.The incidences of G-LOC and spinal injury induced by centrifuge training are low.The training program still needs further development and the training effectiveness should be improved.

Military pilot selection is an effective way to lower the training cost, ensure the safety of pilots and aircraft, and improve the military efficiency, which involves a comprehensive evaluation of medical fitness, psychology and flying aptitude of a pilot candidate.The concept and classification of comprehensive evaluation methods were introduced in this paper.Comprehensive evaluation methods used in domestic and overseas military pilot selection were reviewed.Finally, suggestions on the research and application of the military pilot selection system in China were raised.