212 research outputs found
The diagnostic utility of endocytoscopy for the detection of esophageal lesions: a systematic review and meta-analysis
Objective: To systematically evaluate the value of endocytoscopy (ECS) in the
diagnosis of early esophageal cancer (EC). Methods: Pubmed, Ovid and EMbase
databases were searched to collect diagnostic tests of ECS assisted diagnosis
of early EC. The retrieval time was from the establishment of the database to
August 2022. Review manager 5.4, Stata 16.0 and Meta-Disc 1.4 were used for
meta-analysis after two researchers independently screened literature,
extracted data and evaluated the bias risk of included studies. Results: A
total of 7 studies were included, including 520 lesions. Meta-analysis results
showed that the combined sensitivity(SE), specificity(SP), positive likelihood
ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR) and
positive posterior probability (PPP) of ECS screening for early EC were
0.95[95%CI: 0.84, 0.98], 0.92 [95%CI: 0.83, 0.96], 11.8 [95%CI: 5.3, 26.1],
0.06 [95%CI: 0.02, 0.18], 203 [95%CI: 50, 816], and 75%, respectively. The area
(AUC) under the receiver Operating Characteristic curve (SROC) was 0.98[95%CI:
0.96, 0.99]. Conclusions: Current evidence suggests that ECS can be used as an
effective screening tool for early EC. Due to the limited number and quality of
included studies, it is imperative to conduct more high-quality studies to
verify the above conclusions
Improved Naive Bayes with Mislabeled Data
Labeling mistakes are frequently encountered in real-world applications. If
not treated well, the labeling mistakes can deteriorate the classification
performances of a model seriously. To address this issue, we propose an
improved Naive Bayes method for text classification. It is analytically simple
and free of subjective judgements on the correct and incorrect labels. By
specifying the generating mechanism of incorrect labels, we optimize the
corresponding log-likelihood function iteratively by using an EM algorithm. Our
simulation and experiment results show that the improved Naive Bayes method
greatly improves the performances of the Naive Bayes method with mislabeled
data
Acceleration and displacement dynamic response laws of a shallow-buried bifurcated tunnel
In order to obtain the seismic dynamic laws of the acceleration and displacement of a shallow-buried bifurcated tunnel, the analysis of the numerical simulation was carried out by MIDAS-GTS/NX software. The results of the numerical simulation were verified by a shaking table model test. The results show that: (1) the numerical simulation and shaking table test coincide with each other in terms of variation law and peak value. The results of the numerical simulation are credible. (2) For different tunnel cross-section, the response of acceleration and displacement are significant difference. (3) The seismic response of the small distance tunnel (Section 6) is intense. The seismic response laws of the small distance tunnel are significant difference from other type tunnels. The seismic response of the measuring point at the middle rock column is intense. (4) Along the axis of the tunnel, the displacement of the tunnel firstly increases and then decreases. The displacement of the measuring point at the middle rock column is intense, which is in accordance with the law of the acceleration response. The seismic response laws of the tunnel are significantly affected by the middle rock column. The section structure size has a significant effect on the dynamic response of the tunnel
Study of Three Rotating Radio Transients with FAST
Rotating radio transients (RRATs) are peculiar astronomical objects whose
emission mechanism remains under investigation. In this paper, we present
observations of three RRATs, J1538+2345, J1854+0306 and J1913+1330, observed
with the Five-hundred-meter Aperture Spherical radio Telescope (FAST).
Specifically, we analyze the mean pulse profiles and temporal flux density
evolutions of the RRATs. Owing to the high sensitivity of FAST, the derived
burst rates of the three RRATs are higher than those in previous reports. RRAT
J1854+0306 exhibited a time-dynamic mean pulse profile, whereas RRAT J1913+1330
showed distinct radiation and nulling segments on its pulse intensity trains.
The mean pulse profile variation with frequency is also studied for RRAT
J1538+2345 and RRAT J1913+1330, and the profiles at different frequencies could
be well fitted with a cone-core model and a conal-beam model, respectively.Comment: Sci. China-Phys. Mech. Astron. 62, 959503 (2019
Mechanism of Subordinate Peak Skewing of FBG Sensor during Cracks Propagation Monitoring on Aluminum Alloy Structure
This study investigates the variety of the spectra features of fiber Bragg grating (FBG) around the crack tip during fatigue crack propagation. The study results reveal that the turning of the subordinate peak is significantly associated with crack lengths and corresponds to strain gradient along the FBG. Meanwhile, the strain distribution sensed by the FBG changes with the sensing section of the grating. FBG sensors could observe the monotonic plastic zone ahead of the fatigue crack tip. The cubic strain is distributed along the grating, with monotonic plastic zone propagation at the initial and terminal part of the grating, at approximately a 30% ratio of the entire grating. However, the monotonic plastic zone is sensed by the FBG, at ±15% bias of the grating center, with the quadratic strain gradient pattern along the grating. In particular, when the initial and terminal parts of the grating experience highly inhomogeneous strain distribution, the spectrum distortion occurs
Environmental and spatial factors play different roles in phytoplankton community assembly in different hydrological seasons in Lake Wuchang, China
Lake phytoplankton communities are affected by environmental and spatial factors. We studied the relative importance of environmental and spatial factors on the phytoplankton community assembly in Lake Wuchang across three hydrological seasons, which were divided into dry (December to March), normal (April to June, October to November) and wet seasons (July to September) based on the water level and depth. Spatial and temporal patterns of environmental factors and phytoplankton community composition and diversity were studied using Kruskal–Wallis test, Wilcoxon test and NMDS. CCA, Mantel and partial Mantel tests, and PLS-PM were used to investigate the effects of environmental and spatial factors on phytoplankton community characteristics. Results showed that phytoplankton assemblages at the eight study sites were composed of totally 244 species belonging to 9 phyla, which changed from Bacillariophyta and Chlorophyta to Cyanophyta across the whole hydrological period. There was significantly higher abundance and biomass in the normal and wet seasons than that in the dry season. Phytoplankton alpha diversity exhibited uniform temporal distribution patterns with higher values in the dry season than in the normal and wet seasons. The Mantel and partial Mantel tests revealed that environmental (physicochemical conditions of lake water) and spatial factors (geographic distances among sites) jointly affected the phytoplankton community structure and beta diversity across the hydrological seasons, while spatial factors were more important in the wet season. Partial least squares path models showed that spatial factors exhibited a significant positive correlation with the phytoplankton diversity with the path coefficients of 0.53 and 0.71 in the normal and wet seasons, respectively. Phytoplankton composition had significant correlation with on phytoplankton diversity with the path coefficient of −0.75 and 0.61 in the normal and wet seasons, respectively. Our findings revealed that both environmental and spatial factors affected the phytoplankton community assembly in Lake Wuchang. Environmental factors played a more important role in the dry season, while spatial factors were more important in the wet season. With the exception of the abiotic factors (environmental and spatial), the impacts of biotic factors on phytoplankton community cannot be ignored. Therefore, it is also necessary to strengthen further research on the top-down control over phytoplankton communities in Lake Wuchang
Deep Learning Enables Large Depth-of-Field Images for Sub-Diffraction-Limit Scanning Superlens Microscopy
Scanning electron microscopy (SEM) is indispensable in diverse applications
ranging from microelectronics to food processing because it provides large
depth-of-field images with a resolution beyond the optical diffraction limit.
However, the technology requires coating conductive films on insulator samples
and a vacuum environment. We use deep learning to obtain the mapping
relationship between optical super-resolution (OSR) images and SEM domain
images, which enables the transformation of OSR images into SEM-like large
depth-of-field images. Our custom-built scanning superlens microscopy (SSUM)
system, which requires neither coating samples by conductive films nor a vacuum
environment, is used to acquire the OSR images with features down to ~80 nm.
The peak signal-to-noise ratio (PSNR) and structural similarity index measure
values indicate that the deep learning method performs excellently in
image-to-image translation, with a PSNR improvement of about 0.74 dB over the
optical super-resolution images. The proposed method provides a high level of
detail in the reconstructed results, indicating that it has broad applicability
to chip-level defect detection, biological sample analysis, forensics, and
various other fields.Comment: 13 pages,7 figure
The role of c-reactive protein and fibrinogen in the development of intracerebral hemorrhage: A mendelian randomization study in European population
Background: The causal association of C-reactive protein (CRP) and fibrinogen on intracerebral hemorrhage (ICH) remains uncertain. We investigated the causal associations of CRP and fibrinogen with ICH using two-sample Mendelian randomization. Method: We used single-nucleotide polymorphisms associated with CRP and fibrinogen as instrumental variables. The summary data on ICH were obtained from the International Stroke Genetics Consortium (1,545 cases and 1,481 controls). Two-sample Mendelian randomization estimates were performed to assess with inverse-variance weighted and sensitive analyses methods including the weighted median, the penalized weighted median, pleiotropy residual sum and outlier (MR-PRESSO) approaches. MR-Egger regression was used to explore the pleiotropy. Results: The MR analyses indicated that genetically predicted CRP concentration was not associated with ICH, with an odds ratio (OR) of 1.263 (95% CI = 0.935–1.704, p = 0.127). Besides, genetically predicted fibrinogen concentration was not associated with an increased risk of ICH, with an OR of 0.879 (95% CI = 0.060–18.281; p = 0.933). No evidence of pleiotropic bias was detected by MR-Egger. The findings were overall robust in sensitivity analyses. Conclusions: Our findings did not support that CRP and fibrinogen are causally associated with the risk of ICH
Profiling Plasma Peptides for the Identification of Potential Ageing Biomarkers in Chinese Han Adults
Advancing age is associated with cardiovascular disease, diabetes mellitus and cancer, and shows significant inter-individual variability. To identify ageing-related biomarkers we performed a proteomic analysis on 1890 Chinese Han individuals, 1136 males and 754 females, aged 18 to 82 years, using weak cation exchange magnetic bead based MALDI-TOF-MS analysis. The study identified 44 peptides which varied in concentration in different age groups. In particular, apolipoprotein A-I (ApoA1) concentration gradually increased between 18 to 50 years of age, the levels of fibrinogen alpha (FGA) decreased over the same age span, while albumin (ALB) was significantly degraded in middle-aged individuals. In addition, the plasma peptide profiles of FGA and four other unidentified proteins were found to be gender-dependent. Plasma proteins such as FGA, ALB and ApoA1 are significantly correlated with age in the Chinese Han population and could be employed as indicative ageingrelated biomarkers
- …