Search

3D Local feature description is an essential work in 3D computer vision since a lot of downstream techniques rely on point-to-point correspondences. Most of the existing descriptors perform the description on local surfaces from one single aspect, which inherently results in limited performance. So this paper first proposes a real-valued 3D local feature descriptor named multi-feature fusion histogram (MFFH), which combines five different types of well-designed geometric features to achieve comprehensive descriptions for local surfaces. In addition, to be available for platforms with limited computing and storage resources, we conduct a seamless extension of MFFH to its binary representation B-MFFH by three kinds of directed binarization methods toward different real-valued features. Through extensive evaluation experiments on the benchmark datasets, we prove the superiorities of the proposed MFFH and B-MFFH concerning comprehensive performance. Lastly, the practicability of the proposed MFFH and B-MFFH descriptors is visually demonstrated by the point cloud registration experiments. [ABSTRACT FROM AUTHOR]

Background: Two-dimensional shear wave elastography (2D-SWE) has been proposed for detecting liver fibrosis in biliary atresia. Objectives: To assess the performance of 2D-SWE for detecting advanced liver fibrosis and cirrhosis in patients with biliary atresia. Materials and Methods: Five electronic databases were searched to identify studies investigating the performance of 2D-SWE for diagnosing liver fibrosis in biliary atresia in children. We constructed the summary receiver operating characteristic (SROC) curves of 2D-SWE for detecting advanced liver fibrosis and cirrhosis, and then calculated the area under the SROC curves (AUROCs). Results: Six studies with 470 patients (ages 55 days to 6.6 years) were included. The median correlation coefficient of 2D-SWE with pathological liver fibrosis stages was 0.779 (range: 0.443‒0.813). The summary AUROCs for advanced liver fibrosis and cirrhosis were 0.929 and 0.883, respectively. The summary sensitivity and specificity of 2D-SWE for advanced liver fibrosis were 88% (95% confidence interval [CI]: 80‒94%) and 85% (95% CI: 77‒91%) with I values of 0% and 45.6%, respectively, and for cirrhosis were 80% (95% CI: 72‒87%) and 82% (95% CI: 77‒86%) with I values of 12.9% and 0%, respectively. The diagnostic odds ratio (DOR) of 2D-SWE for advanced liver fibrosis and cirrhosis were 40.3 (95% CI: 18.2‒89.4) and 18.9 (95% CI: 11.2‒31.7), respectively. For preoperative detection of cirrhosis, the pooled AUROC, sensitivity, specificity, and DOR based on the four 2D-SWE studies were 0.877, 79% (95% CI: 71‒86%), 82% (95% CI: 77‒86%), and 17.58 (95% CI: 10.35‒29.85), respectively. Conclusions: Results show that 2D-SWE has potential as a non-invasive tool for detecting advanced liver fibrosis and cirrhosis in patients with biliary atresia. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this meta-analysis was to evaluate the risk of chromosomal abnormalities in fetuses with congenital heart disease (CHD). Methods: Four literature databases were searched until 17th January 2022 using the relevant medical subject heading terms, word variants, and keywords for "congenital heart defect, fetal, and chromosomal abnormalities". The prevalence of overall chromosomal abnormality, aneuploidy, 22q11 deletion, other copy number variants (CNVs), and variants of unknown significance (VOUS) was analyzed. Results: 45 studies met the inclusion criteria for the analysis. The pooled proportion of overall chromosomal abnormalities, aneuploidy, 22q11 deletion, and other CNVs in fetuses with CHD was 23% (95% CI: 20–26%), 19% (95% CI, 16–22%), 2% (95% CI, 2–3%), and 4% (95% CI, 3–5%), respectively. The incidence of overall chromosomal abnormalities, aneuploidy, and other CNVs in non-isolated CHD was higher than in isolated CHD, with odds ratios of 3.08, 3.45, and 4.02, respectively. The incidence of overall chromosomal abnormalities in septal defects was higher than in conotruncal defects and other defects, with odds ratios of 1.60 and 3.61, respectively. In addition, the pooled proportion of VOUS in CHD was 4%. Conclusion: CHD is commonly associated with chromosomal abnormalities. If karyotyping or fluorescence in situ hybridization is normal, chromosomal microarray should be performed to look for submicroscopic abnormalities, especially in fetuses with non-isolated CHD and septal defects. [ABSTRACT FROM AUTHOR]

The intrinsic directional positive thermal gradient of additive manufacturing usually leads to columnar grains crossing several layers and corresponding anisotropy in mechanical properties. However, β titanium alloys usually contain high concentration of β stabilizing elements, which may lead to different microstructure from other titanium alloys by affecting the solidification and solid-state phase transformation process. This research investigated a β Ti-32Mo titanium alloy fabricated by directed energy deposition to analyze its microstructure, microsegragation, mechanical properties and grain structure formation mechanisms in detail. It is found that the as-built alloy, which contains high Mo concentration, consists of near columnar grains in the top layer, however for the rest of the alloy, the grains transform into a near equiaxed structure. Both the near columnar grains and near equiaxed grains show typical dendrite segregation, besides, the microsegregation in deposited layers attenuates gradually under subsequent thermal cycles. There is no anisotropy in mechanical properties in the as built alloy, which is determined by the untextured near equiaxed structure. The near columnar grains can be explained by the constitutional supercooling promoted by high Mo concentration, which encouraged nucleation inside the molten pool and suppressed epitaxial growth from former deposited layer. On the other hand, the near equiaxed grains were transformed from the near columnar grains during the layer by layer manufacturing process, which is first found in titanium alloys fabricated by additive manufacturing. Furthermore, the equiaxed grains formation mechanism was analyzed based on experimental results and a hypothetical mechanism was proposed. [ABSTRACT FROM AUTHOR]

Recent evidence revealed an inhibitory effect of circ-ITCH on the progression of papillary thyroid cancer via affecting the circ-ITCH/miR-22-3p/CBL axis. Rs4911154, an SNP located in circ-ITHC, was previously reported to be significantly associated with an increased risk of hepatocellular carcinoma. Ultrasound testing was used to evaluate the doubling time of thyroid nodules. 202 patients diagnosed with thyroid nodule disorders were divided into three groups according to their genotypes at rs4911154. We found that the A allele was correlated with a shortening doubling time of thyroid nodules. Moreover, the A allele contributed to reduced expression of circ-ITCH/CBL and increased expression of miR-22-3p. Besides, decreased tissue apoptosis was linked to the A allele. Luciferase assays indicated that miR-22-3p could effectively suppress the luciferase activities of CBL and circ-ITCH. Furthermore, manual up-regulation of miR-22-3p effectively suppressed the expression of CBL, while CBL siRNA apparently abolished circ-ITCH induced CBL upregulation, reduced proliferation and increased apoptosis of K1 and TPC-1 cells. A signaling pathway of circ-ITCH/miR-22-3p/CBL axis was established to explain the effect of SNP of circ-ITCH in thyroid tumor malignancy. Compared with the G allele, the A allele in rs4911154 contributed to the malignancy of thyroid nodules with decreased doubling time and down-regulated CBL expression. [ABSTRACT FROM AUTHOR]

Summary: In this work, we used a cross-sectional study to evaluate influence of menarche age, menstrual cycle, menstrual period, menopausal age, and menopause years for osteoporosis in women from China. We found that different menarche age, menstrual cycle, menopausal years, and menopausal age are related with the prevalence of osteoporosis. However, menarche age exceeds 17 years and menopausal age smaller than 48 years are risk factors for osteoporosis in women. Study design: A cross-sectional, population-based study. Purpose: The purpose of this study was to explore relationship between prevalence of osteoporosis and menarche age, menstrual cycle, menstrual period, menopausal age, and menopause years for women. Methods: From March to October 2016, the cluster sampling method was used to conduct an osteoporosis-related questionnaire survey on women aged 40–80 in two communities in Lanzhou City, Gansu, China, and bone mineral density(BMD)was carried out using the DTX-200 dual-energy X-ray absorptiometer produced by the US OSTEOMETER company. The relationship between prevalence of osteoporosis and menarche age, menstrual cycle, menstrual period, menopausal age, and menopause years were analyzed using logistic regression analysis. Results: There were 2224 female participates enrolled in this study and average age was 61.60 ± 8.05 years and total rate of prevalence was 32.73%; among them, different menarche age, menstrual cycle, menopausal years, and menopausal age have statistical differences with the prevalence of osteoporosis, but there is no statistical difference between different menstruation and the prevalence of osteoporosis. Single logistic regression analysis found that older menarche age, earlier menopausal age, and longer menopausal years were related factors for the prevalence of osteoporosis, while menarche age exceed 17 years and menopausal age smaller than 48 years are risk factors for osteoporosis for women in multivariate regression analysis. Conclusions: In China, ages at menarche and menopause are associated with prevalence of osteoporosis. Later, menarche and earlier menopause are associated with higher osteoporosis risk. Menarche and menopause history may help identify women with increased risk of developing osteoporosis. [ABSTRACT FROM AUTHOR]

In this paper, the process of coating AerMet100 steel on forged 300M steel with laser cladding was investigated, with a thorough analysis of the chemical composition, microstructure, and hardness of the substrate and the cladding layer as well as the transition zone. Results show that the composition and microhardness of the cladding layer are macroscopically homogenous with the uniformly distributed bainite and a small amount of retained austenite in martensite matrix. The transition zone, which spans approximately 100 μm, yields a gradual change of composition from the cladding layer to 300M steel matrix. The heat-affected zone (HAZ) can be divided into three zones: the sufficiently quenched zone (SQZ), the insufficiently quenched zone (IQZ), and the high tempered zone (HTZ). The SQZ consists of martensitic matrix and bainite, as for the IQZ and the HTZ the microstructures are martensite + tempered martensite and tempered martensite + ferrite, respectively. These complicated microstructures in the HAZ are caused by different peak heating temperatures and heterogeneous microstructures of the as-received 300M steel. [ABSTRACT FROM AUTHOR]

Due to the restrictions of ports, maneuverability of berthing ships will be affected significantly by water depth. In the present study, numerical simulation of the berthing maneuver of a ship with prescribed translational motion is performed by solving the Reynolds-averaged Navier-Stokes (RANS) equations based on overset grid, and the effects of the quaywall and freesurface are taken into consideration. To validate the present numerical method, comparison is performed between our results and the other results or measurements. It is found that the agreement is significantly better than that resulting from previous CFD-based approach. Subsequently, the effects of various water depths are investigated to evaluate their influences on hydrodynamic forces. The present results can provide helpful guidance on safe maneuvering for vessels' berthing and fender system design in quays. [ABSTRACT FROM AUTHOR]

In the present study, numerical simulation of the berthing maneuver of a ship in the prescribed translational motion is performed. The transient viscous flow and hydrodynamic forces on the hull are calculated by solving the unsteady Reynolds-Averaged Navier-Stokes equations in overset grid system, and the free surface is captured using volume-of-fluid (VOF) approach. The present numerical results have been compared with previous computational results by Toda and available experimental data respectively. Since the effects of the quaywall and free surface are taken into consideration in the present study, it is found that the agreement is significantly better than that resulting from Toda's 3D CFD based approach. Then the effects of various standoff distances between the ship and quaywall on the lateral forces are investigated. Meanwhile, the detailed transient flow features around the berthing ship are obtained, which are helpful to understand the interactional effects between the ship and quaywall. The present results may provide helpful guidance for vessels' safe maneuvering in berthing motion and the design of fender system in the quay. [ABSTRACT FROM AUTHOR]

The fatigue properties of air plasma sprayed (APS) thermal barrier coatings (TBC) were investigated by quantitative Pulsed Thermography (PT). This analysis principally concerned with microstructural evolution during the thermal cyclic. The microstructural features of the specimens were examined by scanning electron microscopy (SEM). The TBC fatigue life was correlated with the development of the thermally grown oxide (TGO) and defects cracks. For better understanding of the thermal response from the surface of TBC, APS TBC samples were inspected as a function of ageing time by PT. The changes in the thermal response amplitude (TRA) were found to correlate with the TGO layer growth and crack nucleation, which was verified by SEM results. The experimental results demonstrated that the thermal response decreased correspondingly along with the increase of the TGO and cracks thickness. The relationships of TRA obtained from the surface of TBC samples with the thickness of TGO and cracks were established. A simple and effective method for quantitative measuring TGO layer and cracks thicknesses using the nondestructive testing of PT was proposed. The experimental results provide a basis for the application of PT in the nondestructive testing of the fatigue properties of TBC thermal fatigue. [ABSTRACT FROM AUTHOR]

We evaluated the expression and diagnostic value of human epididymis protein 4 (HE4) in small cell lung cancer (SCLC). Serum HE4 level was measured in serum samples from 30 healthy controls and 49 patients with SCLC using enzyme-linked immunosorbent assay. HE4 expression in tumor tissues was analyzed by immunohistochemical staining. The results show that serum HE4 level is significantly higher in SCLC patients than those in healthy controls, which is also the case in tumor tissues where strong intracytoplasmic staining is demonstrable. Using the optimal cutoff value of 84.19 pmol/l, serum HE4 level distinguishes SCLC patients from healthy controls with a sensitivity of 69.4 %, a specificity of 93.3 %, and the area under the receiver operating characteristic curve (AUC) of 0.85. Compared to other well-known tumor markers used in lung cancer diagnosis, HE4 shows the highest sensitivity (69.4 %, 34 of 49) and accuracy (78.5 %, 62 of 79) in diagnosing SCLC, and combinations with other tumor markers further increase the sensitivity and accuracy. These findings suggest that HE4 levels are greatly elevated in sera and tumor tissues of patients with SCLC and serum HE4 is a potential diagnostic marker for patients with SCLC. [ABSTRACT FROM AUTHOR]

The prime concern of this paper is the first passage time of a non-homogeneous random walk, which is nearest neighbor but able to stay at its position. It is revealed that the branching structure of the walk corresponds to a 2-type non-homogeneous branching process and the first passage time of the walk can be expressed by that branching process. Therefore, one can calculate the mean and variance of the first passage time, though its exact distribution is unknown. [ABSTRACT FROM AUTHOR]

We derive a quenched moderate deviations principle for the one-dimensional nearest random walk in random environment, where the environment is assumed to be stationary and ergodic. The approach is based on hitting time decomposition. [ABSTRACT FROM AUTHOR]

A wear-resistant alloy consisting of Cr13Ni5Si2 ternary silicide dendrites and the interdendritic nickel-base solid solution (γ) was designed and fabricated by the laser melting/continuous deposition (LMCD) process. The wear resistance of Cr13Ni5Si2/γ alloy was evaluated on an MM-200 block-on-wheel dry sliding wear tester at room temperature. Results indicate that the Cr13Ni5Si2/γ alloy has excellent wear resistance and extremely low load-sensitivity of wear under dry sliding wear test conditions due to the high toughness and the high strength, as well as the transferred cover-layer on the worn surface of the alloy. [ABSTRACT FROM AUTHOR]