Analysis of ocean internal waves imaged by multichannel reflection seismics, using ensemble empirical mode decomposition

Research on ocean internal waves using seismic oceanography is a frontier issue both for marine geophysicists and physical oceanographers. Images of the ocean water layer obtained by conventional processing of multichannel seismic reflection data can show the overall patterns of internal waves. However, in order to extract more information from the seismic data, new tools need to be developed. Here, we use the ensemble empirical mode decomposition (EEMD) method to decompose vertical displacement data from seismic sections and apply this method to a seismic section from the northeastern South China Sea, where clear internal waves are observed. Compared with the conventional empirical mode decomposition method, EEMD has greatly reduced the scale mixing problems induced in the decomposition results. The results obtained show that the internal waves in this area are composed of different characteristic wavelengths at different depths. The depth range of 200–1050 m contains internal waves with a wavelength of 1.25 km that are very well coupled in the vertical direction. The internal waves with a wavelength of 3 km, in the depth range of 200–600 m, are also well coupled, but in an oblique direction; this suggests that the propagation speed of internal waves of this scale changes with depth in this area. Finally, the internal waves with a wavelength of 6.5 km, observed in the depth range of 200–800 m, are separated into two parts with a phase difference of about 90◦, by a clear interface at a depth of 650 m; this allows us to infer an oblique propagation of wave energy of this scale.publishe

The symbiotic bacteria Alcaligenes faecalis of the entomopathogenic nematodes Oscheius spp. exhibit potential biocontrol of plant- and entomopathogenic fungi

Soil-dwelling entomopathogenic nematodes (EPNs) kill arthropod hosts by injecting their symbiotic bacteria into the host hemolymph and feed on the bacteria and the tissue of the dying host for several generations cycles until the arthropod cadaver is completely depleted. The EPN-bacteria-arthropod cadaver complex represents a rich energy source for the surrounding opportunistic soil fungal biota and other competitors. We hypothesized that EPNs need to protect their food source until depletion and that the EPN symbiotic bacteria produce volatile and non-volatile exudations that deter different soil fungal groups in the soil. We isolated the symbiotic bacteria species (Alcaligenes faecalis) from the EPN Oscheius spp. and ran infectivity bioassays against entomopathogenic fungi (EPF) as well as against plant pathogenic fungi (PPF). We found that both volatile and non-volatile symbiotic bacterial exudations had negative effects on both EPF and PPF. Such deterrent function on functionally different fungal strains suggests a common mode of action of A.faecalis bacterial exudates, which has the potential to influence the structure of soil microbial communities, and could be integrated into pest management programs for increasing crop protection against fungal pathogens

A clinical-radiomics nomogram for the prediction of the risk of upper gastrointestinal bleeding in patients with decompensated cirrhosis

ObjectiveTo develop a model that integrates radiomics features and clinical factors to predict upper gastrointestinal bleeding (UGIB) in patients with decompensated cirrhosis.Methods104 decompensated cirrhosis patients with UGIB and 104 decompensated cirrhosis patients without UGIB were randomized according to a 7:3 ratio into a training cohort (n = 145) and a validation cohort (n = 63). Radiomics features of the abdominal skeletal muscle area (SMA) were extracted from the cross-sectional image at the largest level of the third lumbar vertebrae (L3) on the abdominal unenhanced multi-detector computer tomography (MDCT) images. Clinical-radiomics nomogram were constructed by combining a radiomics signature (Rad score) with clinical independent risk factors associated with UGIB. Nomogram performance was evaluated in calibration, discrimination, and clinical utility.ResultsThe radiomics signature was built using 11 features. Plasma prothrombin time (PT), sarcopenia, and Rad score were independent predictors of the risk of UGIB in patients with decompensated cirrhosis. The clinical-radiomics nomogram performed well in both the training cohort (AUC, 0.902; 95% CI, 0.850–0.954) and the validation cohort (AUC, 0.858; 95% CI, 0.762–0.953) compared with the clinical factor model and the radiomics model and displayed excellent calibration in the training cohort. Decision curve analysis (DCA) demonstrated that the predictive efficacy of the clinical-radiomics nomogram model was superior to that of the clinical and radiomics model.ConclusionClinical-radiomics nomogram that combines clinical factors and radiomics features has demonstrated favorable predictive effects in predicting the occurrence of UGIB in patients with decompensated cirrhosis. This helps in early diagnosis and treatment of the disease, warranting further exploration and research

Study on stress intensity factors for crack on involute spur gear tooth

Investigating the stress intensity factors has a great importance to predict the fatigue damage for the involute spur gears. The aim of this article is to reveal the variation laws of stress intensity factors for crack on the involute spur gear tooth. For this purpose, a three-dimensional finite element model for calculating the stress intensity factors of the involute spur gear containing a surface crack is established using the finite element code ABAQUS. Based on the established three-dimensional finite element model, the influences of several parameters, such as torque, friction coefficient, crack depth, crack initial location, and crack size, on mode I, mode II, and mode III stress intensity factors are investigated numerically. The results of the study provide valuable guidelines for enhanced understanding of stress intensity factors for the crack on the involute spur gear tooth

Study of Influence of Boundary Condition of Diffuser with Non-Uniform Velocity on the Jet Characteristics and Indoor Flow Field

In practice, the outflow from a diffuser is highly non-uniform due to many reasons. However, the air outflow velocity from a diffuser is uniform in most current studies. Little research has been conducted to determine under what conditions uniform velocity can be used. Therefore, based on the non-uniformity of velocity, airflow characteristics of grille and ceiling diffusers were investigated experimentally and numerically. Two generic CFD cases (non-uniform and uniform velocity) are presented. The velocity field near the diffuser is investigated with measurements in order to determine velocity-inlet boundary conditions. The study shows that the uniform velocity-inlet boundary condition can be considered accurate only under certain conditions. For the grille diffuser, the aspect ratio affects the distribution of the outflow velocity. Using uniform velocity as the velocity-inlet boundary condition for the grille diffuser would result in at least a 14.2% error in the jet region, except when the outflow aspect ratio is 1 and the average velocity is greater than 1.83 m/s. However, when the average velocity of the ceiling diffuser is 3.64 m/s, the error of using uniform velocity as the velocity-inlet boundary condition reaches 58.3%. This study provides the basis for determining the velocity-inlet boundary conditions during numerical simulations

Serum magnesium levels and lung cancer risk: a meta-analysis

Abstract Background Whether serum magnesium levels were lower in patients with lung cancer than that in healthy controls is controversial. The aim of this study was to identify and synthesize all citations evaluating the relationship between serum magnesium levels and lung cancer. Methods We searched PubMed, WanFang, China National Knowledge Internet (CNKI), and SinoMed databases for relevant studies before December 31, 2017. Two authors independently selected studies, extracted data, and assessed risk of bias. Results Eleven citations comprising 707 cases with lung cancer and 7595 healthy controls were included in our study. Serum magnesium levels were not significantly lower in patients with lung cancer [summary SMD = 0.193, 95%CI = − 1.504 to 1.890] when compared to health controls, with significant heterogeneity (I 2 = 99.6%, P < 0.001) found. Negative associations were found among Asian populations [summary SMD = 0.229, 95%CI = − 1.637 to 2.094] and European populations [summary SMD = − 0.168, 95%CI = − 0.482 to 0.147]. No publication bias was found using the test of Egger and funnel plot. Conclusions Our study suggested that serum magnesium levels had no significant association on lung cancer risk

Rapamycin alleviates renal damage in mice with systemic lupus erythematosus through improving immune response and function

This study aimed to explore the therapeutic effect and mechanism of rapamycin (RAPA) on systemic lupus erythematosus (SLE) in BALB/C mice induced by pristane. The mice were randomly divided into 5 groups (n = 6): control, model, saline, RAPA (1 mg/kg) and RAPA (2 mg/kg). All groups were injected with pristane except control. HE staining revealed 1 mg/kg and 2 mg/kg RAPA treatments obviously alleviated pathological changes in the kidney of SLE mice such as glomeruli enlargement, hyperplasia of mesangial cells, epithelial and endothelial cells, infiltration of inflammatory cells, and edema-like degeneration of renal tubules. Compared with control group, body weights and anti-ribosomal P-protein antibody (ARPA) level of the mice in model group and saline group decreased (P < 0.05), while immune complex deposition and levels of anti-dsDNA antibody, anti-smRNP antibody and urine protein in model group and saline group increased (P < 0.05). However, compared with model group and saline group, body weights of the mice in RAPA (1 mg/kg) group and RAPA (2 mg/kg) group increased (P < 0.05), while immune complex deposition and levels of anti-dsDNA antibody, anti-smRNP antibody, ARPA, and urine protein in RAPA (1 mg/kg) group and RAPA (2 mg/kg) group decreased (P < 0.05). Compared with control group, the proportion of dentritic cells (DC) in the kidney and peripheral blood decreased while the proportion of Th1, Th2 and Th17 cells in the spleen, kidney and peripheral blood increased in model group and saline group (P < 0.05). Compared with model group and saline group, 1 mg/kg and 2 mg/kg RAPA treatments boosted the proportion of DC in the kidney and peripheral blood, reduced the proportion of Th1 and Th17 cells in the spleen, kidney and peripheral blood, and lessened the proportion of Th2 cells in the kidney and peripheral blood (P < 0.05). In conclusion, RAPA alleviated renal damage in SLE mice through improving immune response and function