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A generalized quasilinear (GQL) approximation (Marston , , vol. 116, 2016, 104502) is applied to homogeneous shear turbulence following a previous work on the quasilinear (QL) model (Hernndez & Hwang, , vol. 904, 2020, A11). For the GQL approximation, the velocity fluctuations are decomposed into low- and high-wavenumber groups, the former of which is solved by considering the full nonlinear equations whereas the latter is obtained from the linearised equations around the former. Unlike the QL model, which typically shows significant inhibition of the energy cascade in the direction along which the linearisation is made, the GQL model shows an energy cascade that is more active than the QL model} because more Fourier modes included in the low-wavenumber group allow for an extra energy transfer mechanism from the low- to high-wavenumber group via the so-called `scattering’ mechanism. It is shown that this scattering mechanism is most active when a relatively small and suitable number of Fourier modes are included in the low-wavenumber group instead of a large number of the Fourier modes being so, and this is explained in terms of the neutral Lyapunov vector forming the solution to the linear equations for the high-wavenumber group. As a consequence, the turbulence statics from the GQL model with a relatively small number of the Fourier modes in the low-wavenumber group are closer to those from DNS than those from the model with a large number of the Fourier modes in the low-wavenumber group. Finally, the QL/GQL approximations made in the streamwise and spanwise directions are compared, with emphasis on the role of slow pressure and the related pressure strain transport.

Guoying Zou,1 Qing Zhu,1 Biqiong Ren,1 Qi Guo,1 Yuanyuan Wu,1 Junyu He,1 Ying Wu,1 Zhihong Luo2 1Department of Clinical Laboratory, The Second People’s Hospital of Hunan Province, Changsha, Hunan, 410007, People’s Republic of China; 2Office of the Party Committee, The Second People’s Hospital of Hunan Province, Changsha, Hunan, 410007, People’s Republic of ChinaCorrespondence: Zhihong Luo, Office of the Party Committee, The Second People’s Hospital of Hunan Province, Furong Middle Road 427, Yuhua District, Changsha, Hunan, 410007, People’s Republic of China, Tel +86 19848029533, Email lzh3068@sina.comPurpose: To determine the levels of serum HDL-associated apolipoproteins (apoM and apoC) and HDL-binding receptor (scavenger receptor BI, SR-BI) in patients with gram-negative bacteria sepsis (G-sepsis) and to evaluate the value of lipoproteins in the diagnosis, severity and prognosis of G-sepsis.Patients and Methods: A total of 128 patients with sepsis, 40 patients with system inflammatory reaction syndrome (SIRS) and 40 healthy subjects were enrolled in the Second People’s Hospital of Hunan Province from September 2019 to September 2020. The levels and the correlation of lipoproteins were detected and dynamically monitored by enzyme-linked adsorption method, ROC curve for the diagnostic, severity and prognostic value of lipoproteins in G-sepsis.Results: The levels of serum HDL-associated lipoproteins in patients with G-sepsis were significantly decreased (P < 0.05), and the ROC curve showed that HDL-C, SR-BI, apoM and apoC had cut-off values of 0.915 mmol/L, 122.100 pg/mL, 102.400 ug/mL and 17.55 mg/mL, respectively, for the diagnosis of G-sepsis, with the sensitivity was 85.56%, 97.78%, 93.33% and 73.03%, and the specificity was 95.0%, 82.50%, 61.54% and 82.50%, respectively. There was a correlation between HDL-associated apolipoproteins. Changes in serum HDL-associated lipoproteins were more obvious in shock group than classic inflammation indicators, such as PCT, IL-6 and CRP. They showed a trend change on day 3, with the levels of SR-BI and apoC changing 2– 3 times, and the sensitivity of HDL-C, SR-BI, apoM and apoC for the diagnosis of G-septic shock were 32.43%, 72.97%, 65.75%, and 43.24%, and specificity of 94.34%, 81.13%, 83.07%, and 86.79%, respectively. The AUC, sensitivity and specificity of apoM combined with SR-BI were improved.Conclusion: HDL-associated lipoproteins were correlated with bacterial-infected types, and serum levels of HDL-associated lipoproteins can be used as potential biomarkers for early diagnosis and progress of G-sepsis. ApoM combined with SR-BI could improve the sensitivity and specificity of prognosis assessment.Keywords: apolipoprotein, high-density lipoprotein, gram-negative sepsis, biomarker, prognosis

Given the climate change and more frequent extreme climate events, frozen soils face a potential future extensive degradation. Climate models allow us to understand the possible future course of frozen soil and its effects towards local and global climate. Snow and soil hydrothermal dynamics are the most important parts of the frozen soil land surface process. There have been substantial efforts made to improve snow simulation. Some climate models are already able to realistically reproduce the variability of the snow and its physical parameters. Soil water has a direct impact on soil hydrothermal parameters, topography, and local water circulation under the repeatedly freeze-thaw process. Frequent occurrence of phase change in soil make frozen soil unique in land process simulating. LS3MIP provides us the opportunity to compare the snow and soil moisture condition between a set of climate models’ land components under identical forcing. We collected more than 200 stations in Siberia and Alaska recording snow depth, 2 m air temperature, soil temperature and soil moisture. Together with ERA5-Land reanalysis data, evaluations are done for LS3MIP models. Based on the present results, significant differences are found between the models, especially in terms of soil water content. We will make further analysis to identify the sources of these disagreements., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

Understanding the adsorption mechanism of corticosteroids in the lung surfactant requires the knowledge of corticosteroid molecular interactions with lung surfactant monolayer (LSM). We employed coarse-grained molecular dynamics simulation to explore the action of hydrocortisone on an LSM comprised of a phospholipid, cholesterol and surfactant protein. The structural and dynamical morphology of the lung surfactant monolayer at different surface tensions were investigated to assess the monolayer compressibility. The simulations were also conducted at the two extreme ends of breathing cycles: exhalation (0 mN m-1 surface tension) and inhalation (20 mN m-1 surface tension). The impact of surface tension and hydrocortisone concentration on the monolayer compressibility and stability are significant, resulting the monolayer expansion at higher surface tension. However, at low surface tension, the highly compressed monolayer induces monolayer instability in the presence of the drug due to the accumulation of surfactant protein and drug. The constant area per lipid simulation results demonstrate that the surface pressure-area isotherms show a decrease in area-per-lipid with increased drug concentration. The drug-induced expansion causes considerable instability in the monolayer after a specific drug concentration is attained at inhalation breathing condition, whereas, for exhalation breathing, the monolayer gets more compressed, causing the LSM to collapse. The monolayer collapse occurs for inhalation due to the higher drug concentration, whereas for exhalation due to the accumulation of surfactant proteins and drugs. The findings from this study will aid in enhancing the knowledge of molecular interactions of corticosteroid drugs with lung surfactants to treat respiratory diseases.

JinJian Yao,1,&ast; Hangfei Wang,2,&ast; Weiling Yu,3,&ast; Yimin Li,4 Zhiqian Luo,2 Biao Wu,5 Wei Zhang,6 Xiaoran Liu,2 Chuanzhu Lv6,7 1Emergency Center, Hainan General Hospital Affiliated to Hainan Medical University, Haikou, Hainan, People’s Republic of China; 2Department of Emergency, The First Affiliated Hospital of Hainan Medical University, Haikou, Hainan, People’s Republic of China; 3Oncology Department, Haikou City People’s Hospital, Haikou, Hainan, People’s Republic of China; 4Department of General Surgery, Yang Jiang Hospital of Qiongzhong, Qiongzhong, Hainan, People’s Republic of China; 5Department of Infectious Disease, Hainan General Hospital Affiliated to Hainan Medical University, Haikou, Hainan, People’s Republic of China; 6Emergency and Trauma College of Hainan Medical University, Haikou, Hainan, People’s Republic of China; 7Key Laboratory of Emergency and Trauma, Ministry of Education of Hainan Medical University, Haikou, Hainan, People’s Republic of China&ast;These authors contributed equally to this workCorrespondence: Xiaoran LiuDepartment of Emergency, The First Affiliated Hospital of Hainan Medical University, Haikou, Hainan, People’s Republic of ChinaTel +8613118901829Email liuxiaoran3192@163.comChuanzhu LvKey Laboratory of Emergency and Trauma, Ministry of Education of Hainan Medical University, Haikou, Hainan, People’s Republic of ChinaTel +8617789830771Email lvchuanzhu677@126.comIntroduction: Close contacts of individuals with COVID-19 may directly gain immunity against SARS-CoV-2 despite lacking a detectable infection. This study examined SARS-CoV-2-specific antibodies levels based on gender, age, and exposure source in close contacts of individuals with COVID-19 and compared antibody levels to patients with an asymptomatic or symptomatic COVID-19 infection.Methods: Two patients had confirmed COVID-19 infections at a community hospital in Qiongzhong, Hainan province. Contact tracing identified all individuals in the community who had been exposed to the two patients during the 14 days before their diagnoses. Close contacts quarantined for 14 days, underwent two SARS-CoV-2 tests, and were screened for SARS-CoV-2-specific antibodies at 7 and 12 weeks after the end of quarantine. SARS-CoV-2-specific antibody levels for the close contacts were compared to those for patients with an asymptomatic or symptomatic COVID-19 infection at 7 and 12 weeks after their diagnoses.Results: Contact tracing identified 10,573 individuals in the community, including 360 (3.4%) close contacts. At 7 weeks, 30 (8.33%) close contacts were positive for SARS-CoV-2-specific antibodies (IgG, n = 26 [7.22%]; IgM, n = 4 [1.11%]), which were lower than the proportion of patients with an asymptomatic (IgG, 100% [12/12]) or symptomatic (IgG, 93.6% [44/47]) COVID-19 infection. SARS-CoV-2-specific IgM antibody levels were significantly higher in close contacts who were exposed through a relative compared to a doctor–patient relationship (P = 0.032). SARS-CoV-2-specific IgG antibody levels were significantly higher in close contacts aged < 18 years vs 18– 64 years (P = 0.014). At 12 weeks, SARS-CoV-2-specific IgG antibody levels among close contacts were significantly lower than among patients with an asymptomatic (P = 0.004) or symptomatic COVID-19 infection (P < 0.001).Conclusion: Immune protection conferred by close contact is short term and unlikely to contribute to herd immunity. There remains an unmet public health need for mass vaccination of populations to increase levels of protective antibodies and achieve and maintain herd immunity.Keywords: SARS-CoV-2, COVID-19, antibody, close contact

Wei Sun,1,&ast; Zujin Luo,1,&ast; Jiawei Jin,1 Zhixin Cao,1 Yingmin Ma2 1Department of Respiratory and Critical Care Medicine, Beijing Chaoyang Hospital, Capital Medical University, Beijing, People’s Republic of China; 2Department of Respiratory and Critical Care Medicine, Beijing Youan Hospital, Capital Medical University, Beijing, People’s Republic of China&ast;These authors contributed equally to this workCorrespondence: Yingmin MaDepartment of Respiratory and Critical Care Medicine, Beijing Youan Hospital, Capital Medical University, Beijing, People’s Republic of ChinaTel +86-10-13501185982Email ma.yingmin@163.comPurpose: To determine the effectiveness of neutrophil/lymphocyte ratio (NLR), compared to traditional inflammatory markers, for predicting noninvasive mechanical ventilation (NIMV) failure in acute exacerbation of chronic obstructive pulmonary disease (AECOPD) patients.Patients and Methods: We conducted this retrospective observational study including 212 AECOPD patients who required NIMV during hospitalization from January 2015 to December 2020 in the department of respiratory and critical care medicine of Beijing Chao-Yang Hospital (west campus). We reviewed the medical record to determine if NIMV succeeded or failed for each patient, and compared NLR with traditional markers (leukocyte, C-reactive protein [CRP] and procalcitonin [PCT]) between NIMV failure and NIMV success group. Receiver-operating characteristic (ROC) curve and multivariate logistic regression analysis were used to assess the accuracy of these markers for predicting NIMV failure.Results: A total of 38 (17.9%) patients experienced NIMV failure. NLR was a more sensitive biomarker to predict NIMV failure (AUC, 0.858; 95% CI 0.785– 0.931) than leukocyte counts (AUC, 0.723; 95% CI 0.623– 0.823), CRP (AUC, 0.670; 95% CI 0.567– 0.773) and PCT (AUC, 0.719; 95% CI 0.615– 0.823). There was statistically positive correlation between NLR and leukocytes count (r=0.35, p< 0.001), between NLR and CRP (r=0.258, p< 0.001), between NLR and PCT (r=0.306, p< 0.001). The cutoff value of NLR to predict NIMV failure was 8.9 with sensitivity 0.688, specificity 0.886 and diagnostic accuracy 0.868. NLR> 8.9 (odds ratio, 10.783; 95% CI, 2.069– 56.194; P=0.05) was an independent predictor of NIMV failure in the multivariate logistic regression model.Conclusion: NLR may be an effective marker for predicting NIMV failure in AECOPD patients, and the patients with NLR> 8.9 should be handled with caution since they are at higher risk of NIMV failure and require intubation. Further study with a larger sample size and with more data is necessary to confirm our study.Keywords: COPD, noninvasive mechanical ventilation, neutrophil/lymphocyte ratio, predictor, failure, NIMV, NLR, chronic obstructive pulmonary disease

In this work, the particulate matter less than 10 μm (PM10) emissions from a medium-sized passenger vehicle's front brake wear were studied using a finite element analysis (FEA) and experimental approaches. The world harmonised light-duty vehicle test procedure-brake (WLTP-B) cycle was chosen to simulate real-world driving. An electrical low-pressure impactor (ELPI+) was used to count the brake wear particles on a brake dynamometer sealed in a chamber. In addition, a machine learning method, namely, extreme gradient boosting (XGBoost), was employed to capture the feature importance rankings of braking conditions contributing to brake wear PM10 emissions. The simulated PM10 emissions were quite consistent with the measured ones, with an overall relative error of 9%, indicating that the proposed simulation approach is promising to predict brake wear PM10 during the WLTP-B cycle. The simulated and experimental PM10 emission factors during the WLTP-B cycle were 6.4 mg km−1 veh−1 and 7.0 mg km−1 veh−1, respectively. Among the 10 trips of the WLTP-B cycle, the measured PM10 of trip #10 was the largest contributor, accounting for 49% of total PM10 emissions. On the other hand, the XGBoost results revealed that the top five most important factors governing brake wear PM10 emissions were dissipation energy, initial braking speed, final rotor temperature, braking power, and deceleration rate. From the perspective of friendly driving behaviour and regulation, limiting severe braking and high-speed braking has the potential to reduce PM10 emissions from brake wear.