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

Rapid and ultrasensitive detection of pathogen-associated biomarkers is vital for the early diagnosis and therapy of bacterial infections. Herein, we developed a close-packed and ordered Au@AgPt array coupled with a cascade triggering strategy for surface-enhanced Raman scattering (SERS) and colorimetric identification of the Staphylococcus aureus biomarker micrococcal nuclease (MNase) in serum samples. The trimetallic Au@AgPt nanozymes can catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) molecules to SERS-enhanced oxidized TMB (oxTMB), accompanied by the color change from colorless to blue. In the presence of S. aureus, the secreted MNase preferentially cut the nucleobase AT-rich regions of DNA sequences on magnetic beads (MBs) to release alkaline phosphatase (ALP), which subsequently mediated the oxTMB reduction for inducing the colorimetric/SERS signal fade away. Using this "on-to-off" triggering strategy, the target S. aureus can be recorded in a wide linear range with a limit of detection of 38 CFU/mL in the colorimetric mode and 6 CFU/mL in the SERS mode. Meanwhile, the MNase-mediated strategy characterized by high specificity and sensitivity successfully discriminated between patients with sepsis (n = 7) and healthy participants (n = 3), as well as monitored the prognostic progression of the disease (n = 2). Overall, benefiting from highly active and dense "hot spot" substrate, MNase-mediated cascade response strategy, and colorimetric/SERS dual-signal output, this methodology will offer a promising avenue for the early diagnosis of S. aureus infection.

Objective: To investigate the awareness of knowledge about hepatitis C prevention and control among outpatients in Ningbo City, Zhejiang Province, and its influencing factors, so as to provide the evidence for strengthening health education on hepatitis C prevention and control. Methods: Based on sentinel surveillance of hepatitis C, the outpatients aged 15 to 65 years at seven hospitals in Yinzhou District, Cixi City and Xiangshan County of Ningbo City were selected using the convenient sampling method from April to June during 2020 and 2022. Demographic information, knowledge and behaviors related to hepatitis C prevention and control were collected through questionnaire surveys. The influencing factors for knowledge about hepatitis C prevention and control were analyzed using a multivariable logistic regression model. Results: A total of 2 792 participants were surveyed, including 1 157 males (41.44%) and 1 635 females (58.56%). The awareness rate of knowledge about hepatitis C prevention and control was 56.23%, and was lower in knowledge about hepatitis C vaccine and treatment. The awareness rates of knowledge about hepatitis C prevention and control among outpatients from 2020 to 2022 were 47.11%, 53.22% and 70.65%, respectively, showing an upward trend (P<0.05). Multivariable logistic regression analysis showed that participants aged 25 to <50 years (OR=1.358, 95%CI: 1.073-1.719), with an educational level of high school or junior college (OR=1.431, 95%CI: 1.134-1.806) or above junior college (OR=3.728, 95%CI: 2.958-4.699), with household monthly income per capita of 3 000 to <5 000 yuan (OR=1.828, 95%CI: 1.344-2.486) or ≥5 000 yuan (OR=1.858, 95%CI: 1.366-2.526), without a history of invasive treatments such as pedicure in public places (OR=1.287, 95%CI: 1.024-1.618), without a history of contact with family members' blood-contaminated items (OR=2.050, 95%CI: 1.552-2.707), and always using condoms during sexual contacts (OR=1.740, 95%CI: 1.273-2.378) had higher awareness of knowledge about hepatitis C prevention and control. Conclusions The awareness of knowledge about hepatitis C vaccine and treatment among outpatients in Ningbo City needs to be improved. Age, educational level, household monthly income per capita, history of invasive treatments such as pedicure in public places, history of contact with family members' blood-contaminated items and frequency of condom use during sexual contacts are associated with outpatients' awareness of knowledge about hepatitis C prevention and control.

AIM: To investigate the changes of microRNA-34a(miR-34a)and microRNA-29b(miR-29b)levels in lens epithelial cells of age-related cataracts(ARC)patients and their clinical significance.METHODS: A total of 65 ARC patients(study group)and 53 cases of clear lens anterior capsulorhexis(control group)who visited our hospital from February 2023 to February 2024 were gathered. Pearson was applied to test the correlation between miR-34a and miR-29b. Multifactor Logistic regression was applied to determine the factors affecting the occurrence of ARC.RESULTS: Compared with the control group, the expression levels of miR-34a and miR-29b in lens epithelial cells of the research group showed a significant decrease trend(all P<0.05). There was a positive correlation between miR-34a and miR-29b in the lens epithelial cells of ARC patients(r=0.472, P<0.05). MiR-34a and miR-29b were influence factors for ARC(all P<0.05).CONCLUSION: The levels of miR-34a and miR-29b in lens epithelial cells of ARC patients are significantly reduced, which is associated with the occurrence of ARC.

Gelsemium elegans (G. elegans) is an extremely poisonous plant that is widely distributed in southern China and southeastern Asia. G. elegans poisoning events occur frequently in southern China, and are therefore an urgent public health problem requiring multidisciplinary action. However, the toxic components and toxicological mechanisms remain unclear. Here, we describe a systematic investigation on the toxic components of G. elegans, resulting in the isolation and identification of 120 alkaloids. Based on acute toxicity screening, the structure-toxicity relationship of Gelsemium alkaloids was proposed for the first time. Moreover, gelsedine- and humantenine-type alkaloids were detected in the clinical blood sample, and were confirmed to be causative in the poisoning. The most toxic compound, gelsenicine (1), had selective inhibitory effects toward ventral respiratory group (VRG) neurons in the medulla, which is the main brain region controlling respiration in the central nervous system. Gelsenicine (1) strongly inhibited the firing of action potentials in VRG neurons through its ability to stimulate GABA_A receptors, the main receptors involved in inhibitory neurotransmission. Application of GABA_A receptor antagonists successively reversed action potential firing in gelsenicine (1)-treated VRG neurons. Importantly, the GABA_A receptor antagonists securinine and flumazenil significantly increased the survival of poisoned animals. Our findings provide insight into the components and mechanisms of G. elegans toxicity, and should assist the development of effective emergency treatments for G. elegans poisoning.

Objective To investigate the interaction between a novel antimicrobial compound,HL-J6,and penicillin-binding protein 1(PBP1)of Staphylococcus aureus.Methods With MRSA252 genomic DNA as the template and PBP1F and PBP1R as primers,the expression plasmid pET30a-pbp1-39-608 was constructed by amplifying the target gene fragment followed by cloning into the Nde I/Xho I restriction sites of the pET30a vector.Then the obtained plasmids were transformed into Escherichia coli for the expression of PBP1-39-608 protein,and the product was purified by affinity chromatography.The inhibitory effect of HL-J6 on the transpeptidase activity of PBP1-39-608 was measured using peptidoglycan side chain backbone peptide,with thiol ester analog S2d as the substrate.The affinity between HL-J6 and PBP1-39-608 was detected using microscale thermophoresis(MST),and the binding interaction was confirmed by cellular thermal shift assay(CETSA).Molecular docking and dynamics simulation were performed using AutoDock Vina and Desmond software,respectively,to elucidate the binding mode of HL-J6 with the PBP1-39-608 protein and the key amino acid residues involved.Results The recombinant plasmid pET30a-pbp1-39-608 was successfully constructed,and PBP1-39-608 protein was produced after induction and purified,yielding a protein with an approximate molecular mass of 65×103.HL-J6 inhibited the transpeptidase activity of PBP1-39-608 in a time-dependent manner(P<0.001).The dissociation constant Kd of the binding between HL-J6 and PBP1-39-608 was 64.92 μmol/L.Molecular docking results showed that HL-J6 bound to the active pocket of PBP1-39-608 by interacting with key residues such as ILE-348,ASN-370,THR-516 and PHE-423,with a binding score of-8.38 kcal/mol(<-5.00 kcal/mol).Dynamics simulation results indicated that the complex became stable after 50 ns.Conclusion HL-J6 effectively inhibits the transpeptidase activity of Staphylococcus aureus PBP1,and shows stable interaction with the protein.

Objective To explore the value of ultrasound artificial intelligence(AI)in assisting naval grassroots doctors for the diagnosis of thyroid nodule in naval.Methods A total of 177 patients with thyroid nodules(200 thyroid nodules)who visited The First Affiliated Hospital of Naval Medical University from November 2020 to November 2023 were selected as research objects.The thyroid nodules were diagnosed by naval grassroots doctors,naval grassroots doctors assisted by AI,and senior doctors,respectively.Results The pathological results showed that there were 110 malignant nodules and 90 benign nodules.The diagnostic accuracy rate of AI-assisted group(85.0%)was similar to that of senior doctor group(87.0%),which were higher than that of naval grassroots doctor group(71.5%).Pathological results were taken as the gold standard,Kappa consistency test was carried out,and the area under the receiver operating characteristic(ROC)curve(AUC)was compared among groups.The diagnostic results of naval grassroots doctor group had a moderate consistency with pathological results(Kappa value was 0.424,P<0.001).The diagnostic results of AI group and senior doctor group had strong consistencies with pathological results(Kappa values were 0.693 and 0.735,respectively,both P<0.001).There was no significant difference in the AUC between AI group and senior doctor group(0.842 vs.0.864,P>0.05).However,there was a significant difference in the AUC between naval grassroots doctor group and AI group(0.712 vs.0.842,P<0.001).Conclusion AI can assist naval grassroots doctors in improving the diagnostic level of thyroid nodules.It has certain application prospects in naval forces.

Abstract On 18 May 2021, the Center for Disease Control and Prevention (CDC) of X District in P City, Z Province received a co-investigation of a suspected case of intentional HIV transmission from the public security branch, and conducted epidemiological investigations on Zhao and Wang (both males). Wang was confirmed HIV-positive in 2019. Zhao had unprotected sexual encounters several times with Wang in March 2021 without being informed of Wang's HIV infection. Zhao developed fever, sore throat and other symptoms of acute infection phase on 28 March, and were confirmed HIV positive by the CDC of P City on 11 May. Zhao did not have sex with anyone else before or after having sex with Wang. In addition, Zhao had no history of surgery, blood transfusions, drug use or any other history of HIV exposure. Laboratory tests conducted by the CDC of Z Province showed that the HIV nucleic acid sequences between the samples of Zhao and Wang had a high degree of homology. Combined with the epidemiological investigation, laboratory testing and the evidence from the public security branch, it was concluded that Wang intentionally transmitted HIV to Zhao through unprotected anal sex without disclosing his HIV infection status.

Objective:To explore the value of radiomics and deep learning in predicting the efficacy of initial transarterial chemoembolization (TACE) for hepatocellular carcinoma (HCC).Methods:This was a cohort study. The imaging and clinical information of HCC patients treated with TACE in the Second Affiliated Hospital of Harbin Medical University from January 2015 to January 2021 were collected retrospectively. A total of 265 patients were divided into response group (175 cases) and non-response group (90 cases) according to the modified solid tumor efficacy evaluation criteria (mRECIST) 1 to 2 months after initial TACE. According to the proportion of 8∶2, the patients were randomly divided into training group (212 cases, 140 responders and 72 non-responders) and test set (53 cases, 35 responders and 18 non-responders). Univariate and multivariate logistic regression was used to screen clinical variables and construct a clinical model. The radiomics features were extracted from the preoperative CT images, and radiomics model was constructed after feature dimensionality reduction. Using the deep learning method, three residual network (ResNet) models (ResNet18, ResNet50 and ResNet101) were established, and their effectiveness was compared and integrated to build a deep learning model with best performance. Univariate and multivariate logistic regression was used to combine pairwise three models to establish the combined model. The receiver operating characteristic curve was used to evaluate the performance of the model to distinguish between TACE response and non-response groups.Results:In the test set, the area under the curve (AUC) of the clinical model and the radiomics model in the differentiation between response and non-response after TACE were 0.730 (95% CI 0.569-0.891) and 0.775 (95% CI 0.642-0.907). The AUC of ResNet18, ResNet50 and ResNet101 were 0.719, 0.748 and 0.533, respectively. The AUC for deep learning model obtained by integrating ResNet18 and ResNet50 was 0.806 (95% CI 0.665-0.946). After pairwise fusion, the combined deep learning-radiomics model showed the highest performance, with an AUC of 0.843 (95% CI 0.730-0.956), which was better than those of the deep learning-clinical model (AUC of 0.838, 95% CI 0.719-0.957) and the radiomics-clinical model (AUC of 0.786, 95% CI 0.648-0.898). Conclusions:The combined model of radiomics and deep learning has high performance in predicting the curative effect of TACE in patients with HCC before operation.

Objective To explore the impact factors on early neurological deterioration(END)in patients with cerebral infarction combined with coronavirus disease 2019(COVID-19).Methods The clinical characteristics and laboratory of patients with acute ischemic stroke and COVID-19 in Brain Hospital Affiliated to Nanjing Medical University were retrospectively analyzed from December 15,2022 to January 15,2023.According to whether or not END occurred,all patients were divided into END group and non-END group.The clinical data of two groups were analyzed.Results A total of eligible 56 patients were included in this study,with 16 cases in END group and 40 cases in non-END group.The average age of END group(74.31±12.04)was older than non-END group(67.18±8.15)(P＜0.05).The proportion of previous history of coronary heart disease and diabetes were higher than non-END group(all P＜0.05).In terms of laboratory examination,the number of monocytes,C-reactive protein,glycated hemoglobin,lactate dehydrogenase,myoglobin,albumin,D-dimer,and fibrin degradation products in END group were significantly higher than that in non-END group(all P＜0.05).Logistic analysis showed that C-reactive protein is an independent risk factor for cerebral infarction combined with COVID-19(OR =1.084,95%CI:1.002-1.173,P＜0.05).Area under the ROC curve was0.825(95%CI:0.709-0.941,P＜0.001).Conclusions For patients with cerebral infarction combined with COVID-19,early neurological deterioration is more likely to occur in elderly patients with multiple underlying diseases,abnormal coagulation and inflammation indicators.Increased C-reactive protein has good predictive ability.