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

ObjectiveTo investigate the mechanism of neferine（Nef） in promoting vascular regeneration against cerebral ischemia through modulation of mitochondrial calcium uniporter（MCU） ion channel. MethodTaking the area of subintestinal vessels in microvascular deficiency zebrafish as an index， the vascular regenerative efficacy of Nef was evaluated， and the median effective concentration（EC₅₀） was calculated. Rats were randomly divided into a sham operation group， a model group， a positive drug group（butylphthalide， 6 mg·kg^-1）， and Nef low， medium， and high dose groups（0.125， 0.625， 3.125 μg·kg^-1）. Except for the sham operation group， the middle cerebral artery occlusion（MCAO） model was established in other groups. After modeling， the groups were administered the corresponding dose of drugs by gavage， while the sham operation and model groups received equal volumes of saline， once a day for 7 consecutive days. Neurobehavioral scores were assessed for each group of rats， and the infarct rate of ischemic brain tissue was calculated by 2，3，5-triphenyltetrazolium chloride（TTC） staining. The regional cerebral blood flow（rCBF） of each group was measured using a speckle contrast imaging. Immunofluorescence and Western blot were conducted to detect the expression of vascular endothelial growth factor（VEGF）， platelet endothelial cell adhesion molecule-1（CD31）， and hypoxia-inducible factor-1α（HIF-1α） proteins in each group. Human umbilical vein endothelial cells（HUVECs） were divided into the normal group， model group， positive drug group（astragaloside Ⅳ， 10 μmol·L^-1）， and Nef group （32 nmol·L^-1）. In the verification of mitochondrial protection of Nef and its mechanism in promoting vascular regeneration， the spermine（MCU agonist） and Nef+spermine group were added. HUVECs model of oxygen-glucose deprivation（OGD） was established in all groups except the normal group， the cell viability was assessed using 3-（4，5-dimethylthiazol-2-yl）-2，5-diphenyltetrazolium bromide（MTT） assay， and cell migration ability was evaluated through scratch and tube formation assays. Fluorescent probes（Rhod-2 AM， Fluo-3 AM， JC-1， Calcein AM） and a cellular energy metabolism analyzer were used to analyze the mitochondrial protective effects of Nef. Molecular docking was performed to predict the binding ability of Nef with MCU and HIF-1α， and Western blot was used to detect the effects of Nef on the protein expressions of MCU， B-cell lymphoma-2 associated X protein（Bax）， Caspase-3 and HIF-1α in the OGD model HUVECs. ResultThe results of vascular regeneration in microvascular deficiency zebrafish showed that compared to the normal group， the area of subintestinal vessels in the model group significantly decreased（P<0.01）. Compared to the model group， different concentrations of Nef could significantly increase the area of subintestinal vessels（P<0.01）， with the maximum tolerated concentration of 10.24 μmol·L^-1 and the EC₅₀ of 0.23 μmol·L^-1. Anti-cerebral ischemia results on MCAO rats showed that compared to the sham operation group， the model group had a significant decrease in rCBF and a significant increase in infarct rate， while CD31 expression significantly decreased（P<0.01）， and VEGF and HIF-1α protein expressions significantly increased（P<0.05）. Compared to the model group， the treated groups showed significant increases in rCBF， significant reductions in infarct volume， and significant increases in CD31， VEGF， and HIF-1α protein expression（P<0.01）. Cell experiment results showed that compared to the normal group， the model group had decreased cell viability and migration ability， increased intracellular Ca²⁺ and mitochondrial Ca²⁺ levels， reduced mitochondrial permeability transition pore（MPTP） opening， and decreased mitochondrial energy metabolism capability， with increased expressions of MCU， Bax， Caspase-3 and HIF-1α proteins（P<0.05， P<0.01）. Compared to the model group， the Nef group showed increased cell viability and migration ability， decreased intracellular Ca²⁺ and mitochondrial Ca²⁺ levels， increased MPTP opening， enhanced mitochondrial energy metabolism capability， decreased expressions of MCU， Bax and Caspase-3 proteins， and increased HIF-1α protein expression（P<0.05， P<0.01）. ConclusionNef can stabilize mitochondrial membrane potential and inhibit mitochondrial apoptosis. By down-regulating the expression of MCU， it suppresses the activation of intracellular Bax and Caspase-3 while activating the HIF-1α signaling pathway， enhancing the expression of VEGF and CD31， thereby promoting vascular regeneration to treat ischemic brain injury.

Objective:To explore the current situation and influencing factors of amputation decision-making dilemma of diabetic foot patients.Methods:From July to December 2023, 200 patients with diabetic foot in the Tianjin Medical University General Hospital and Tianjin Medical University Chu Hsien-I Memorial Hospital were selected as study subjects by convenience sampling. General Information Questionnaire, Decisional Conflict Scale (DCS), Family APGAR Index, and Hospital Anxiety and Depression Scale were used to conduct a cross-sectional survey. Pearson correlation was used to analyze the correlation between diabetic foot patients' amputation decision-making dilemma and family caring, anxiety and depression, and multiple linear regression was used to analyze the influencing factors of diabetic foot patients' amputation decision-making dilemma.Results:A total of 200 questionnaires were distributed, and 180 valid questionnaires were collected, with a valid response rate of 90.0% (180/200). The DCS score of 180 patients with diabetic foot was (30.04±9.77), 76.7% (138/180) patients scored ≥25.0, and they had decision-making dilemma, and 25.0% (45/180) of patients scored ≥37.5, indicating decision-making delay. Multiple linear regression analysis showed that occupational status, diabetes course, family caring, anxiety and depression were the influencing factors of amputation decision-making dilemma of diabetic foot patients ( P<0.05) . Conclusions:Diabetic foot patients face certain dilemmas in the process of amputation decision-making. Clinical medical and nursing staff should reasonably evaluate the patient's occupational status, disease course, family caring, and psychological state, and develop personalized decision support strategies to improve decision quality and prevent changes in the patient's condition caused by delayed decision-making.

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.

Globally, gynecological malignancies are common types of female cancer and the main cause of cancer death among women. Cervical cancer, endometrial cancer and ovarian cancer, which are the main types of gynecological cancers, pose a significant threat to women's health worldwide. Studies have shown that diet plays an important role in the occurrence and development of gynecological cancers such as cervical cancer, endometrial cancer, and ovarian cancer, for which added sugar may be an influencing factor due to its food source characteristic and related biological effect. However, this paper reviewed the research progress on the relationship between consumption of added sugar and gynecological cancers such as endometrial cancer, ovarian cancer and cervical cancer, with a view to providing a reference for the active prevention of gynecological cancer.

Objective:To provide ideas and references for improving the lumbar stability of flying personnel by reviewing the research progress and tendency on Schmorl′s nodes of lumbar spine in flying personnel. Literature resource and selection Relevant papers and monographs about Schmorl′s nodes published at home and abroad. Literature quotation Thirty-six published references were cited. Literature synthesis It is generally considered that Schmorl′s nodes of lumbar spine are cartilaginous nodes formed by the herniation of the intervertebral discs tissue into the vertebral body through the broken cartilaginous endplates. There are different opinions on the epidemiology and pathogenesis of Schmorl′s nodes of lumbar spine. Because most of them have no obvious clinical symptoms, they were once considered to be of no research value. However, the investigation showed that the further study on Schmorl′s nodes of lumbar spine in flying personnel is realistic. Schmorl′s nodes of lumbar spine may not only cause lumbago, but also are closely related to lumbar intervertebral discs degeneration. The formation of Schmorl′s nodes of lumbar spine in flying personnel will affect the viscoelasticity of lumbar intervertebral discs, and this will affect their anti-G and anti-vibration abilities, accelerate the degeneration of lumbar spine and intervertebral discs, and induce clinical symptoms or reduce flight endurance. Conclusions:Schmorl′s nodes of lumbar spine are closely related to lumbar disc degeneration and lumbar instability. Schmorl′s nodes are commonly seen in the lumbar spine and have an important effect on the overall stability of lumbar spine of flying personnel.

Objective:To provide ideas and references for improving the lumbar stability of flying personnel by reviewing the research progress and tendency on Schmorl′s nodes of lumbar spine in flying personnel. Literature resource and selection Relevant papers and monographs about Schmorl′s nodes published at home and abroad. Literature quotation Thirty-six published references were cited. Literature synthesis It is generally considered that Schmorl′s nodes of lumbar spine are cartilaginous nodes formed by the herniation of the intervertebral discs tissue into the vertebral body through the broken cartilaginous endplates. There are different opinions on the epidemiology and pathogenesis of Schmorl′s nodes of lumbar spine. Because most of them have no obvious clinical symptoms, they were once considered to be of no research value. However, the investigation showed that the further study on Schmorl′s nodes of lumbar spine in flying personnel is realistic. Schmorl′s nodes of lumbar spine may not only cause lumbago, but also are closely related to lumbar intervertebral discs degeneration. The formation of Schmorl′s nodes of lumbar spine in flying personnel will affect the viscoelasticity of lumbar intervertebral discs, and this will affect their anti-G and anti-vibration abilities, accelerate the degeneration of lumbar spine and intervertebral discs, and induce clinical symptoms or reduce flight endurance. Conclusions:Schmorl′s nodes of lumbar spine are closely related to lumbar disc degeneration and lumbar instability. Schmorl′s nodes are commonly seen in the lumbar spine and have an important effect on the overall stability of lumbar spine of flying personnel.

Objective:To study the specific mechanism of LINC01018 involved in the pathogenesis of colon cancer.Methods:The expression of LINC01018 in colon cancer tissues and cells and normal colon tissues and cells were detected by real time fluorescence quantitative polymerase chain reaction (qRT-PCR). HT-29 cell line which overexpresses LINC01018 stably was established. RNA binding protein immunoprecipitation (RIP) assay was used to detect the interaction between LINC01018 and E2F1 protein. Dual luciferase assay was used to detect the regulatory effect of E2F1 on CDK6 promoter. The expression of E2F1 or CDK6 was up-regulated in HT-29 cell line which overexpresses LINC01018, then the proliferation, invasion and migration of HT-29 cells and the expression of CDK6 and matrix metalloproteinase-2 (MMP-2) in HT-29 cells were detected by cell counting method (CCK-8) assay, Transwell assay and Western blot.Results:The expression of LINC01018 was abnormally low in colon cancer tissues and cells. The result of RIP assay showed that LINC01018 interacted with E2F1 protein. The result of dual luciferase assay showed that E2F1 protein could enhance the efficiency of CDK6 promoter, and E2F1 had a positive regulatory effect on CDK6. Overexpression of LINC01018 could attenuate the positive regulatory effect of E2F1 on CDK6. Up-regulation of E2F1 or CDK6 expression could attenuate the effects of LINC01018 overexpression on the proliferation, invasion, migration and expression of CDK6 and MMP-2 in HT-29 cells.Conclusions:The expression of LINC01018 was abnormally low in colon cancer tissues and cells. LINC01018 may regulate the proliferation, invasion and migration of HT-29 cells through E2F1/CDK6/MMP-2 axis, and participate in the pathogenesis of colon cancer.

Objective To investigate the mechanism of efflux pump AcrAB-TolC involved in the cross-resistance between quaternary ammonium compounds ( QAC) and fluoroquinolones ( FQ) in Escherich-ia coli. Methods Seventy-eight Escherichia coli strains were isolated from clinical samples and then tested for the sensitivity to benzalkonium bromide by ager dilution method. Six strains were randomly selected and induced with benzalkonium bromide. Changes in the sensitivity of these strains to benzalkonium bromide and ciprofloxacin were analyzed after induction. Expression of the efflux pump genes acrA, acrB and tolC at mRNA level in the induced strains and their parent strains were detected by quantitative real-time PCR. Re-sults Among the 78 strains, the minimum inhibitory concentrations ( MIC) ranged from 8 μg/ml to 64μg/ml and 47. 4％ of strains have higher MIC than the standard strain. Compared with the parent strains, the induced strains showed higher expression of acrA and tolC genes, and the differences between the two groups were statistically significant. The MIC values of ciprofloxacin to the six induced strains were 4-8 times higher than those to their parent strains. Conclusions It was speculated that the increased expression of acrA and tolC genes at transcription level in the induced strains were related to the cross-resistance between quaternary ammonium compounds and fluoroquinolone antibiotics.

Objective To investigate the distribution and drug resistance of carbapenem-resistant Enterobacteriaceae ( CRE) isolated from children in China. Methods CRE strains were collected in 10 ter-tiary children's hospitals of China from January 1, 2016 to December 31, 2017. Antimicrobial susceptibility of the clinical strains was detected with disk diffusion method ( KB method) and automated method. The re-sults were analyzed according to the Clinical and Laboratory Standards Institute ( CLSI) Standards published in 2017. WHONET 5. 6 software was used to retrospectively analyze the distribution characteristics and drug resistance of these strains. Results A total of 3065 CRE clinical strains were isolated from children with an overall prevalence of 7. 7％ and among them, 13. 5％ were isolated in neonatal group and 5. 8％ in non-neo-natal group. The detection rate of CRE in 2017 was higher than that in 2016 (9. 7％ vs 5. 7％). Among the 3065 CRE strains, there were 1912 strains of Klebsiella pneumoniae (62. 0％), 667 strains of Escherichia coli (22. 0％), 206 strains of Enterobacter cloacae (7. 0％), 56 strains of Klebsiella aerogenes (1. 8％) and 47 strains of Serratia marcescens (1. 5％). Most of the strains were isolate in neonatology departments including neonatal intensive care units (NICU) and intensive care units (ICU), accounting for 44. 8％ and 19. 7％, respectively. Respiratory tract (61. 8％), urine (19. 4％) and blood (5. 7％) specimens were the main sources of CRE isolates. Results of antimicrobial susceptibility test showed that the CRE strains were highly resistant to carbapenem antibiotics such as imipenem, meropenem and ertapenem, as well as penicillins and most cephalosporins (79. 6％-100％), especially those isolated in the neonatal group (P<0. 05). Children had relatively low resistance rates to aminoglycosides such as amikacin (19. 7％) and fos-fomycin (11. 9％), fluoroquinolones such as levofloxacin (37. 7％) and ciprofloxacin (43. 3％), and tige-cycline (3. 8％). Currently, no polymyxin B-resistant strains were isolated. Conclusions The prevalence of common CRE strains in children in 2017 was higher than that in 2016, especially in newborns. Drug re-sistance in CRE strains isolated from neonates to common antibiotics was more severe, suggesting that great attention should be paid to it and timely measures should also be taken.