•Use metamodel to estimate the time-dependent failure probability (TDFP).•The proposed methods reduce computational cost drastically.•AK-co-IS is based on the optimal time-dependent design ...point.•AK-co-SS transforms small TDFP into a series of larger conditional ones.
For efficiently estimating the time-dependent failure probability, two new methods named as the active learning Kriging (AK) coupled with importance sampling (AK-co-IS) and AK coupled with subset simulation (AK-co-SS) are proposed. The proposed methods are based on the fact that the AK coupled with Monte Carlo simulation (AK-MCS) method has been proved to be a very efficient method. However, for problem with small time-dependent failure probability or long service time, the size of candidate sample pool generated by MCS would be so large that the efficiency of AK-MCS is reduced. Therefore, the AK-co-IS and AK-co-SS are proposed to highly enhance the computational efficiency by greatly reducing the candidate sample pool size. And these two methods reduce the candidate sample pool size respectively by searching the optimal time-dependent design point to increase the ratio of failure samples and converting a rare event simulation problem into sequence of more frequent event ones. Through iteratively constructing the AK model to be convergent by the U-learning function in the IS and SS sample pools, respectively, the computational cost of estimating the time-dependent failure probability would reduce drastically compared with AK-MCS. Several examples are used to illustrate the efficiency and accuracy of the proposed methods.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
An ultrasonic phased array defect extraction method based on adaptive region growth is proposed, aiming at problems such as difficulty in defect identification and extraction caused by noise ...interference and complex structure of the detected object during ultrasonic phased array detection. First, bilateral filtering and grayscale processing techniques are employed for the purpose of noise reduction and initial data processing. Following this, the maximum sound pressure within the designated focusing region serves as the seed point. An adaptive region iteration method is subsequently employed to execute automatic threshold capture and region growth. In addition, mathematical morphology is applied to extract the processed defect features. In the final stage, two sets of B-scan images depicting hole defects of varying sizes are utilized for experimental validation of the proposed algorithm's effectiveness and applicability. The defect features extracted through this algorithm are then compared and analyzed alongside the histogram threshold method, Otsu method, K-means clustering algorithm, and a modified iterative method. The results reveal that the margin of error between the measured results and the actual defect sizes is less than 13%, representing a significant enhancement in the precision of defect feature extraction. Consequently, this method establishes a dependable foundation of data for subsequent tasks, such as defect localization and quantitative and qualitative analysis.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
•EIS is introduced to study the structural characteristics of SRM.•The equivalent circuit of SRM physical property indices are established.•The mapping relationships are established to express the ...cemented state of SRM.•The propagation mode of the charged matter inside the SRM is explored.•The mathematical expression of the SRM material transfer mode is derived.
Geotechnical problems in extremely complex environments have become increasingly prominent, which raises the need to explore more efficient solutions. Multidisciplinary approaches show a new perspective to deal with these problems. In this study, the electrochemical impedance spectroscopy (EIS) was introduced to illustrate the structural characteristics of soil-rock mixtures (SRM), aiming at deducing the relationship between physical property indices such as the mass ratio indices (e.g., water content, soil-rock ratio, and stone particle size) and volume ratio indices (e.g., porosity and saturation) and equivalent circuit at the macro and micro levels. A three-level equivalent circuit corresponding with the physical characteristic of SRM was established to describe the cementation state. It shows that the degree of cementation of SRM increases with increasing water content, rock content, and median size of block stone; meanwhile, the real impedance coefficient of the non-cemented part is lower than that of the cemented part. The corresponding relationship between the imaginary impedance and the specific gravity has segmental characteristics. The density first increases and then decreases with the increase of water content; the water content and saturation threshold are 16% and 80 ± 2%, respectively. Moreover, the saturation (Sr and n∙Sr) decreases with the increase in the real impedance coefficient. In addition, the characteristics of the propagation mode and interfacial contact characteristics of the charged material inside SRM were examined, and the macro and micro mapping of the cementation state of SRM and the basic mass transfer mode (i.e., migration, diffusion, and convection) were obtained. The mapping relationship proposed in this study reflects the micro-scale cementation characteristics and the macro-scale physical characteristics of the SRM system, which provides new insight into the multi-scale research of SRM.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
With the increase in demand for metal resources, research on deep-sea polymetallic nodule mining has been reinvigorated, but the problem of its environmental impact cannot be ignored. No matter what ...method is used for mining, it will disturb the surface sediments of the seabed, thereby increasing the concentration of suspended solid particles and metal ions in the water body, changing the properties of the near-bottom water body and sediments, and affecting biological activity and the living environment. Focusing on the ecological and environmental impacts of deep-sea polymetallic nodule mining, taking as our main subject of focus the dynamic changes in sediments, we investigated the environmental impacts of nodule mining and their relationships with each other. On this basis, certain understandings are summarized relating to the ecological and environmental impacts of deep-sea polymetallic nodule mining, based on changes in the engineering geological properties of sediment, and solutions for current research problems are proposed.
The association between COVID-19 symptoms and antibody responses against SARS-CoV-2 is poorly characterized. We analyzed antibody levels in individuals with known SARS-CoV-2 infection to identify ...potential antibody-symptom associations. Convalescent plasma from 216 SARS-CoV-2 RNA+ individuals with symptomatology information were tested for the presence of IgG to the spike S1 subunit (Euroimmun ELISA), IgG to receptor binding domain (RBD, CoronaCHEK rapid test), and for IgG, IgA, and IgM to nucleocapsid (N, Bio-Rad ELISA). Logistic regression was used to estimate the odds of having a COVID-19 symptom from the antibody response, adjusting for sex and age. Cough strongly associated with antibodies against S1 (adjusted odds ratio aOR = 5.33; 95% CI from 1.51 to 18.86) and RBD (aOR = 4.36; CI 1.49, 12.78). In contrast, sore throat significantly associated with the absence of antibodies to S1 and N (aOR = 0.25; CI 0.08, 0.80 and aOR = 0.31; 0.11, 0.91). Similarly, lack of symptoms associated with the absence of antibodies to N and RBD (aOR = 0.16; CI 0.03, 0.97 and aOR = 0.16; CI 0.03, 1.01). Cough appeared to be correlated with a seropositive result, suggesting that SARS-CoV-2 infected individuals exhibiting lower respiratory symptoms generate a robust antibody response. Conversely, those without symptoms or limited to a sore throat while infected with SARS-CoV-2 were likely to lack a detectable antibody response. These findings strongly support the notion that severity of infection correlates with robust antibody response.
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•Leuconostoc mesenteroides F24 was first used as an adjunct starter in gray sufu fermentation.•Inoculation of L. mesenteroides F24 changed the profiles of the volatile ...compounds.•Inoculation of L. mesenteroides F24 significantly improved the flavor quality of gray sufu.•Nine compounds were confirmed to be the key aroma-active compounds in gray sufu.
Gray sufu is a traditional fermented bean product with strong flavor in China, but traditional fermentation methods often lead to its off-flavor. This study was performed to investigate the flavor quality characteristics of gray sufu fermented using L. mesenteroides F24. Results showed 220 volatile compounds in gray sufu, among which alcohols and esters were the main volatiles. Inoculation with L. mesenteroides F24 considerably affected the contents of flavor substances in gray sufu and substantially increased the main flavor compounds. In addition, 29 kinds of key volatile compounds were identified by analyzing the ROAVs. Four unique key flavor substances were found in gray sufu inoculated with L. mesenteroides F24. This study is the first report on the feasibility of L. mesenteroides F24 as a promising starter culture to improve the flavor quality of gray sufu. The results provide a theoretical basis for improving the processing and quality control of gray sufu.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Abstract
Background
The efficacy of coronavirus disease 2019 (COVID-19) convalescent plasma (CCP) is primarily ascribed as a source of neutralizing anti-severe acute respiratory syndrome coronavirus ...2 (SARS-CoV-2) antibodies. However, the composition of other immune components in CCP and their potential roles remain largely unexplored. This study aimed to describe the composition and concentrations of plasma cytokines and chemokines in eligible CCP donors.
Methods
A cross-sectional study was conducted among 20 prepandemic healthy blood donors without SARS-CoV-2 infection and 140 eligible CCP donors with confirmed SARS-CoV-2 infection. Electrochemiluminescence detection-based multiplexed sandwich immunoassays were used to quantify plasma cytokine and chemokine concentrations (n = 35 analytes). A SARS-CoV-2 microneutralization assay was also performed. Differences in the percentage of detection and distribution of cytokine and chemokine concentrations were examined by categorical groups using Fisher’s exact and Wilcoxon rank-sum tests, respectively.
Results
Among CCP donors (n = 140), the median time since molecular diagnosis of SARS-CoV-2 was 44 days (interquartile range = 38–50) and 9% (n = 12) were hospitalized due to COVID-19. Compared with healthy blood donor controls, CCP donors had significantly higher plasma levels of interferon (IFN)-γ, interleukin (IL)-10, IL-15, IL-21, and macrophage-inflammatory protein-1, but lower levels of IL-1RA, IL-8, IL-16, and vascular endothelial growth factor-A (P < .0014). The distributions of plasma levels of IL-8, IL-15, and IFN-inducible protein-10 were significantly higher among CCP donors with high (≥160) versus low (<40) anti-SARS-CoV-2 neutralizing antibody titers (P < .0014). The median levels of IL-6 were significantly higher among CCP donors who were hospitalized versus nonhospitalized (P < .0014).
Conclusions
Heterogeneity in cytokine and chemokine composition of CCP suggests there is a different inflammatory state among the CCP donors compared with SARS-CoV-2 naive, healthy blood donors.
Compared to controls, COVID-19 convalescent plasma (CCP) had higher distributions of IFN-γ, IL-10, IL-15, IL-21, and MCP-1 but lower IL-1RA, IL-8, IL-16, and VEGF-A. Between CCP with low versus high neutralizing antibody titers, IL-8, IL-15 and IP-10 distributions varied significantly.
Background:
Stiff person syndrome spectrum disorders (SPSD) are a rare group of disabling neuroimmunological disorders. SPSD often requires immune therapies, especially in the setting of inadequate ...response to symptomatic treatments. The safety and efficacy of therapeutic plasma exchange (TPE) in SPSD remains uncertain.
Objectives:
To describe the safety, tolerability, and efficacy of TPE in patients with SPSD.
Design:
A retrospective observational study.
Methods:
A retrospective review of SPSD patients seen at Johns Hopkins Hospital (JHH) from 1997 to 2021 was performed. Patient demographics/history, examination/diagnostic findings, treatment response, and TPE-related complications were recorded. Assessment for any associations between clinical characteristics, including age, sex, clinical phenotype, and time on immunotherapy, and response to TPE 3 months after treatment was performed. A subgroup of 18 patients treated with TPE at JHH and 6 patients treated with TPE at outside institutions were evaluated for any change in usage of symptomatic medications 3 months after the TPE treatment. Literature review of SPSD and TPE was also conducted.
Results:
Thirty-nine SPSD patients were treated with TPE (21 at JHH and 18 at outside institutions); median age 48 years, 77% female, median modified Rankin Scale 3; mean initial anti-GAD65 antibody titer was 23,508 U/mL. Twenty-four patients (62%) had classic SPS, 10 (26%) had SPS-plus, 2 (5%) had progressive encephalomyelitis with rigidity and myoclonus, and 3 (8%) had pure cerebellar ataxia. All patients were on symptomatic treatments, 30 (77%) previously received IVIg, and 3 (8%) previously received rituximab. Four patients (10%) had a TPE-related adverse event. One developed asymptomatic hypotension, another had both line thrombosis and infection, and two had non-life-threatening bleeding events. Twenty-three (59%) patients reported improvement in symptoms after TPE. Of the subgroup of 24 patients evaluated for any change in usage of symptomatic medications 3 months after the TPE treatment, 14 (58%) required fewer GABAergic symptomatic medications. Literature review identified 57 additional patients with SPSD; 43 (75%) reported temporary improvement after TPE.
Conclusion:
The majority of patients treated with TPE had improvement. Moreover, most patients evaluated for any change in usage of symptomatic medications after the TPE treatment no longer required as much symptomatic medications months after TPE. TPE appears safe and well-tolerated in SPSD. Further studies are needed to assess the long-term efficacy of TPE in SPSD and identify which patients may benefit the most from TPE.
•A new efficient method for estimating failure probability is proposed.•The proposed method inherits the advantage of Meta-IS.•The proposed method inherits the efficiency of the AK-IS.•The proposed ...method is a wise combination of Meta-IS and AK-IS.•The proposed method is suitable for problems with multiple failure domains.
For efficiently estimating the failure probability of the structure with multiple implicit failure domains, a method abbreviated as Meta-IS-AK is proposed by combining the adaptive Kriging Meta model Importance Sampling (Meta-IS) and Importance Sampling based Adaptive Kriging (IS-AK). In the proposed method, the failure probability is equivalently expressed as a product of the augmented failure probability and the correction factor, then two steps are respectively established to solve two terms. In the first step, Meta-IS algorithm is executed to generate IS samples. The augmented failure probability can be estimated as a byproduct in the first step. In the second step, all these IS samples compose a sample pool, in which the AK model is subsequently reconstructed for accurately predicting failure domain indicators instead of the actual implicit limit state function. Then the failure domain indicator at each IS sample and further the correction factor can be efficiently estimated. From the strategy of the proposed method, it can be seen that the proposed Meta-IS-AK possesses both the advantages of the Meta-IS method suitable for multiple failure domains and efficiency of the AK model for accurately predicting the failure domain indicators at all IS samples, which is demonstrated by the numerical and engineering examples.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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