A deep transfer learning network for structural condition identification with limited real-world training data

Structural condition identification based on monitoring data is important for automatic civil infrastructure asset management. Nevertheless, the monitoring data is almost always insufficient, because the real-time monitoring data of a structure only reflects a limited number of structural conditions, while the number of possible structural conditions is infinite. With insufficient monitoring data, the identification performance may significantly degrade. This study aims to tackle this challenge by proposing a deep transfer learning (TL) approach for structural condition identification. It effectively integrates physics-based and data-driven methods, by generating various training data based on the calibrated finite element (FE) model, pretraining a deep learning (DL) network, and transferring its embedded knowledge to the real monitoring/testing domain. Its performance is demonstrated in a challenging case, vibration-based condition identification of steel frame structures with bolted connection damage. The results show that even though the training data are from a different domain and with different types of labels, intrinsic physics can be learned through the pretraining process, and the TL results can be clearly improved, with the identification accuracy increasing from 81.8% to 89.1%. The comparative studies show that SHMnet with three convolutional layers stands out as the pretraining DL architecture, with 21.8% and 25.5% higher identification accuracy values over the other two networks, VGGnet-16 and ResNet-18. The findings of this study advance the potential application of the proposed approach towards expert-level condition identification based on limited real-world training data

NDM-1-producing Enterobacteriaceae in a teaching hospital in Shanghai, China: IncX3-type plasmids may contribute to the dissemination of blaNDM-1

SummaryObjectivesTo provide the epidemiological dissemination and the genetic characteristics of blaNDM-1 in a teaching hospital in Shanghai, China.MethodsHere, the carbapenemase genes of 114 CRE isolates were evaluated by polymerase chain reaction (PCR). Clonal relatedness was assessed by pulsed-field gel electrophoresis (PFGE). Conjugation experiments and Southern blot hybridization were performed to determine the transferability of plasmids. Then plasmids were completely sequenced by the shotgun method.ResultsTwo Klebsiella pneumoniae strains (RJA1227 and RJF866) and one Raoultella planticola strain (RJA274) were identified as NDM-1 positive. The two K. pneumoniae isolates belonged to ST11 and exhibited highly similar PFGE patterns. Shotgun sequencing showed that plasmid pRJF866 (ca. 110kb) contained genes associated with the IncFII-FIB group and was highly similar to plasmid pKOX_NDM1. RJA274 (ca. 50kb) harbored blaNDM-1 on an IncX3 plasmid, which was nearly identical to plasmid pNDM-HN380 except that part of the ISAba125 element is missing.ConclusionThis is the first report of NDM-1-positive Enterobacteriaceae from Shanghai, China. IncX3 plasmids, reported in various species in the United Arab Emirates and China, may contribute to the dissemination of blaNDM-1.. More attention should be devoted to monitoring the dissemination of the NDM-1 gene due to its potential horizontal transfer via mobile genetic elements

Screening key genes for abdominal aortic aneurysm based on gene expression omnibus dataset

Abstract Background Abdominal aortic aneurysm (AAA) is a common cardiovascular system disease with high mortality. The aim of this study was to identify potential genes for diagnosis and therapy in AAA. Methods We searched and downloaded mRNA expression data from the Gene Expression Omnibus (GEO) database to identify differentially expressed genes (DEGs) from AAA and normal individuals. Then, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analysis, transcriptional factors (TFs) network and protein-protein interaction (PPI) network were used to explore the function of genes. Additionally, immunohistochemical (IHC) staining was used to validate the expression of identified genes. Finally, the diagnostic value of identified genes was accessed by receiver operating characteristic (ROC) analysis in GEO database. Results A total of 1199 DEGs (188 up-regulated and 1011 down-regulated) were identified between AAA and normal individual. KEGG pathway analysis displayed that vascular smooth muscle contraction and pathways in cancer were significantly enriched signal pathway. The top 10 up-regulated and top 10 down-regulated DEGs were used to construct TFs and PPI networks. Some genes with high degrees such as NELL2, CCR7, MGAM, HBB, CSNK2A2, ZBTB16 and FOXO1 were identified to be related to AAA. The consequences of IHC staining showed that CCR7 and PDGFA were up-regulated in tissue samples of AAA. ROC analysis showed that NELL2, CCR7, MGAM, HBB, CSNK2A2, ZBTB16, FOXO1 and PDGFA had the potential diagnostic value for AAA. Conclusions The identified genes including NELL2, CCR7, MGAM, HBB, CSNK2A2, ZBTB16, FOXO1 and PDGFA might be involved in the pathology of AAA

Towards a Fairer Green city: measuring unfairness in daily accessible greenery in Chengdu’s Central city

Urban green spaces exert beneficial effects on both individuals and communities. However, as urban sprawl intensifies, socioeconomic disparities widen, and populations burgeon, the concepts of green fairness and environmental justice confront substantial hurdles. The daily exposure to greenery emerges as a crucial determinant of these factors, yet no comprehensive methodologies currently exist to gauge the levels of daily accessible urban greenery or to probe the distribution of green inequities. In this research, we harness the capabilities of Spatial Design Network Analysis (sDNA) to scrutinize spatial choice and integration, using the metropolis of Chengdu as a case study. Three indicators representing daily accessed urban greenery are utilized, including the Green View Index (GVI) at the street level, the assessment of green spaces based on the Normalized Differential Vegetation Index (NDVI), and the level of greenery within the visible range of buildings. Green Accessibility Index (GAI) was further proposed and calculated for three states of commuting, recreation, and work to synthesize the accessibility and greenness levels. The distribution of green unfairness in the study area are evaluated using bivariate local spatial autocorrelation. Our findings reveal that (1) frequent expressway commuting and existing greenery does not satisfy urban fairness needs. (2) Significant differences in unfair areas of building visible greenery (3) Unfair areas are concentrated in high-income neighborhoods (4) Severe unfairness between greenery and population in large cities, where most people do not enjoy the benefits of adequate greenery. We provide recommendations based on these findings, thereby offering actionable insights to optimize the spatial distribution of green unfairness through enhanced accessibility of urban greenery

Timing of Endovascular Interventions for Iliac Vein Compression Syndrome With Thrombus

The aim of this study is to explore the timing and method of endovascular intervention for iliac vein compression syndrome (IVCS) with thrombus. Data from 111 patients with IVCS, complicated acute deep vein thrombosis (DVT), or post-thrombotic syndrome (PTS) who underwent endovascular interventions were analyzed retrospectively. Patients were divided into Group A (DVT group), including 56 patients with IVCS and iliofemoral DVT, with or without femoropopliteal DVT, with sudden lower limb swelling, and Group B (PTS group) included 55 patients with IVCS and PTS, including 18 with lower extremity wet ulcers and 32 with lower limb infections. Interventional therapies were used to treat the thrombus and eliminate stenosis and occlusion of the iliac vein. In both groups, clinical symptoms in the lower limbs after surgery were reduced significantly, and PTS incidence was low during long-term follow-up. The cumulative patency rate was 75.2% in the DVT group and 88.6% in the PTS group. Comprehensive interventional therapies are safe and effective in patients with IVCS and thrombi. Long-term efficacy in the PTS group tended to be better than that in the DVT group

Distribution, Source and Risk Assessment of Heavy Metal(oid)s in Water, Sediments, and Corbicula Fluminea of Xijiang River, China

A total of 43 water and sediment samples, and 34 Corbicula fluminea samples were collected in Xijiang River in southern China to determine the spatial distribution and sources of 12 metals/metalloids (V, Co, Cr, Ni, Cu, Mn, Zn, Cd, Pb, As, Sb, and Tl) and to assess the pollution levels and ecological risks of the pollutants. The results showed that the levels of the metals/metalloids (except for Tl) in the river water from almost all of the sampling sites met the Chinese national surface water quality standards. However, the concentrations of the metals/metalloids in the sediments exceeded the background values by a factor of 1.03–56.56 except for V, Co, and Mn, and the contents of Zn, Cd, and Pb in the Corbicula fluminea soft tissue exceeded the limits of the Chinese Category I food Quality Standards. The spatial distribution analysis showed that the concentrations of the contaminants in the lower reaches of Xijiang River were higher than in the upper reaches. The bioaccumulation factor (BAF), biota-sediment accumulation factor (BSF), geo-accumulation index (Igeo), and the potential ecological risk index (RI) were obtained to assess the pollution levels and ecological risks. The results indicated that Cu, Cd, and Zn were the most prone to bio-accumulation in the Corbicula fluminea soft tissue, and the lower reaches showed a much higher pollution level and risk than the upper reaches. The metals/metalloids in the sediments posed serious threat on the aquatic ecosystem, of which Cd, As, and Sb are the most risky contaminants. The results of principal component analysis (PCA) indicated Cr, Ni, Cu, Mn, Cd, Pb, and As in the sediments came from relevant industrial activities, and V and Co originated from natural sources, and Sb from mining activities, Zn and Tl came from industrial activities and mining activities

Optimizing Li_1.3Al_0.3Ti_1.7(PO₄)₃ Particle Sizes toward High Ionic Conductivity

NASICON-type Li1.3Al0.3Ti1.7(PO4)3 (LATP) has attracted a lot of attention because of its high ionic conductivity and stability to air and moisture. However, the size effect of LATP primary particles on ionic conductivity is ignored. In this study, different sizes of LATP particles are prepared to investigate the morphology, relative density, and ionic conductivity of the LATP solid electrolyte. The influences of particle size and sintering temperature on the microstructure, phase composition, and electrical properties of LATP ceramics were systematically studied. The medium-sized LATP particle (2 μm) presents a great microstructure with a high relative density of over 97%, the highest ionic conductivity of 6.7 × 10–4 S cm–1, and an activation energy of 0.418 eV. The Li–Li symmetric cells and Li–LFP batteries delivering good electrochemical performance were fabricated with highly conductive LATP ceramics. These results make significant strides in elucidating the relationship between the particle sizes of LATP and its electrochemical performance

Crown Width Extraction of <i>Metasequoia glyptostroboides</i> Using Improved YOLOv7 Based on UAV Images

With the progress of computer vision and the development of unmanned aerial vehicles (UAVs), UAVs have been widely used in forest resource investigation and tree feature extraction. In the field of crown width measurement, the use of traditional manual measurement methods is time-consuming and costly and affects factors such as terrain and weather. Although the crown width extraction method based on the segmentation of UAV images that have recently risen in popularity extracts a large amount of information, it consumes long amounts of time for dataset establishment and segmentation. This paper proposes an improved YOLOv7 model designed to precisely extract the crown width of Metasequoia glyptostroboides. This species is distinguished by its well-developed terminal buds and distinct central trunk morphology. Taking the M. glyptostroboides forest in the Qingshan Lake National Forest Park in Lin’an District, Hangzhou City, Zhejiang Province, China, as the target sample plot, YOLOv7 was improved using the simple, parameter-free attention model (SimAM) attention and SIoU modules. The SimAM attention module was experimentally proved capable of reducing the attention to other irrelevant information in the training process and improving the model’s accuracy. The SIoU module can improve the tightness between the detection frame and the edge of the target crown during the detection process and effectively enhance the accuracy of crown width measurement. The experimental results reveal that the improved model achieves 94.34% [email protected] in the task of crown detection, which is 5% higher than that achieved by the original model. In crown width measurement, the R2 of the improved model reaches 0.837, which is 0.151 higher than that of the original model, thus verifying the effectiveness of the improved algorithm

Infection-prevention and control interventions to reduce colonisation and infection of intensive care unit-acquired carbapenem-resistant Klebsiella pneumoniae: a 4-year quasi-experimental before-and-after study

Abstract Objective To determine whether infection-prevention and control (IPC) interventions can reduce the colonisation and infection of intensive care unit (ICU)-acquired carbapenem-resistant Klebsiella pneumoniae (CRKP) in a general ICU ward in China. Methods We used a quasi-experimental before-and-after study design. The study was conducted in 4 stages: baseline period, January 2013–June 2013; IPC interventions period including de-escalation and targeted bundle interventions, July 2013–June 2014; modified IPC interventions period, July 2014–June 2015; and follow-up period, July 2015–June 2016. We used modified de-escalation interventions according to patient-risk assessments to prevent the transmission of CRKP. Results A total of 629 patients were enrolled in study. The incidence of ICU-acquired CRKP colonisation/infection was 10.08 (4.43–16.43) per 1000 ICU patient-days during the baseline period, and significantly decreased early during the IPC interventions, but the colonisation/infections reappeared in April 2014. During the modified IPC intervention and follow-up periods, the incidence of ICU-acquired CRKP colonisations/infections reduced to 5.62 (0.69–6.34) and 2.84 (2.80–2.89), respectively, with ongoing admission of cases with previously acquired CRKP. The incidence of ICU-acquired CRKP catheter-related bloodstream infections decreased from 2.54 during the baseline period to 0.41 during the follow-up period. The incidence of ventilator-associated pneumonia and skin and soft tissue infections showed a downward trend from 2.84 to 0.41 and from 3.4 to 0.47, respectively, with slight fluctuations. Conclusions Comprehensive IPC interventions including de-escalation and targeted bundle interventions showed a significant reduction in ICU-acquired CRKP colonisations/infections, despite ongoing admission of patients colonised/infected with CRKP