Search

The rotor misalignment fault, which occurs only second to unbalance, easily occurs in the practical rotating machinery system. Rotor misalignment can be further divided into coupling misalignment and bearing misalignment. However, most of the existing references only analyze the effect of coupling misalignment on the dynamic characteristics of the rotor system, and ignore the change of bearing excitation caused by misalignment. Based on the above limitations, a five degrees of freedom nonlinear restoring force mathematical model is proposed, considering misalignment of bearing rings and clearance of cage pockets. The finite element model of the rotor is established based on the Timoshenko beam element theory. The coupling misalignment excitation force and rotor unbalance force are introduced. Finally, the dynamic model of the ball bearing-coupling-rotor system is established. The radial and axial vibration responses of the system under misalignment fault are analyzed by simulation. The results show that the bearing misalignment significantly influences the dynamic characteristics of the system in the low-speed range, so bearing misalignment should not be ignored in modeling. With the increase of rotating speed, rotor unbalance and coupling misalignment have a greater impact. Misalignment causes periodic changes in bearing contact angle, radial clearance, and ball rotational speed. It also leads to reciprocating impact and collision between the ball and cage. In addition, misalignment increases the critical speed and the axial vibration of the system. The results can provide a basis for health monitoring and misalignment fault diagnosis of the rolling bearing-rotor system.

Analysis of dynamic characteristics of the defective bearing is significant for the fault diagnosis of the machinery. At present, there are few researches on numerical modeling of bearing with defective roller. To solve this problem, explicit finite element method is adopted in this paper to establish a nonlinear dynamic model of the cylindrical roller bearing with roller spalling defects. In the proposed model, the flexibility of all the components, the internal friction, the relative sliding, the finite size of the roller and the rollers-to-cage contact force are all considered. Then the proposed dynamic model is verified theoretically and experimentally. The vibration responses of bearing and the sliding behavior of defective roller and cage are analyzed based on the proposed numerical model. The results show that the roller-to-cage contact force will be increased and the slippage of the defective roller will be aggravated when the roller defect occurs. In addition, the increment of defect width and number of defective rollers will aggravate the vibration of bearing and the sliding of cage.

Objective The L1 cell adhesion molecule (L1CAM) gene, encodes the L1 cell adhesion molecule, is involved in the central nervous system development. Its mutations result in L1 syndrome which is associated with brain malformation and nervous developmental delay. Case report We presented three fetuses with hydrocephalus and agenesis of the corpus callosum detected by ultrasound, followed by medical exome sequencing (MES) test with L1CAM mutations: two known missense mutation c.551G > A (p. R184Q) and c.1354G > A (p. G452R), and a novel frameshift mutation c.1322delG which causes the early termination of translation (p. G441Afs∗72). By utilizing multiple computational analysis, all the variants were scored to be likely pathogenic. Conclusion Combined use of ultrasound and MES to identify the molecular etiology of fetal anomalies may contribute to expanding our knowledge of the clinical phenotype of L1 syndrome observed in the south Chinese population.

Hand action recognition is an important part of intelligent monitoring, human–computer interaction, robotics and other fields. Compared with other methods, the hand action recognition method using skeleton information can ignore the error effects caused by complex background and movement speed changes, and the computational cost is relatively small. The spatial-temporal graph convolution networks (ST-GCN) model has excellent performance in the field of skeleton-based action recognition. In order to solve the problem of the root joint and the further joint not being closely connected, resulting in a poor hand-action-recognition effect, this paper firstly uses the dilated convolution to replace the standard convolution in the temporal dimension. This is in order to process the time series features of the hand action video, which increases the receptive field in the temporal dimension and enhances the connection between features. Then, by adding non-physical connections, the connection between the joints of the fingertip and the root of the finger is established, and a new partition strategy is adopted to strengthen the hand correlation of each joint point information. This helps to improve the network’s ability to extract the spatial-temporal features of the hand. The improved model is tested on public datasets and real scenarios. The experimental results show that compared with the original model, the 14-category top-1 and 28-category top-1 evaluation indicators of the dataset have been improved by 4.82% and 6.96%. In the real scene, the recognition effect of the categories with large changes in hand movements is better, and the recognition results of the categories with similar trends of hand movements are poor, so there is still room for improvement.

Combined Oxidative Phosphorylation Deficiency 23 (COXPD23) caused by mutations in GTPBP3 gene is a rare mitochondrial disease, and this disorder identified from the Chinese population has not been described thus far. Here, we report a case series of three patients with COXPD23 caused by GTPBP3 mutations, from a severe to a mild phenotype. The main clinical features of these patients include lactic acidosis, myocardial damage, and neurologic symptoms. Whole genome sequencing and targeted panels of candidate human mitochondrial genome revealed that patient 1 was a compound heterozygote with novel mutations c.413C > T (p. A138V) and c.509_510del (p. E170Gfs∗42) in GTPBP3. Patient 2 was a compound heterozygote with novel mutations c.544G > T (p. G182X) and c.785A > C (p.Q262P), while patient 3 was a compound heterozygote with a previously reported mutation c.424G > A (p.E142K) and novel mutation c.785A > C (p.Q262P). In conclusion, we first describe three Chinese individuals with COXPD23, and discuss the genotype-phenotype correlations of GTPBP3 mutations. Our findings provide novel information in the diagnosis and genetic counseling of patients with mitochondrial disease.

Paper based humidity sensors are low-cost, flexible, and biodegradable. However, the previously reported paper based humidity sensors exhibit poor repeatability, low sensitivity, high drift, and slow response. Here, we reported a new strategy to monolithically fabricate humidity sensor based on porous paper (PPHS) using robust and precise screen and gravure printings. PPHS is highly sensitive, with the maximum 1480% change at 1 kHz and the maximum 411.4% change at 10 kHz in capacitance, respectively. PPHS is highly repeatable (a 1.05% standard derivation in sensitivity for 3 continuous runs) and is stable and insensitive to a mild temperature change (15-30 °C). PPHS rapidly responds (0.8 s) and recovers (0.78 s). PPHS is also highly foldable and twistable. The high repeatability, high sensitivity, quick response/recovery, high foldability/twistability, and good stability of PPHS could be attributable to the combined effects of the high specific surface area of porous paper and the robust and precise printings. By comparison, PPHS is more sensitive than the previously reported paper-based humidity sensors and several humidity sensors fabricated using different substrates, materials, and printings. Due to these unique features, PPHS shows great potential applications in the humidity sensing, the breath detection, the proximity detection, and non-touch switch.

Combined Oxidative Phosphorylation Deficiency 23 (COXPD23) caused by mutations in GTPBP3 gene is a rare mitochondrial disease, and this disorder identified from the Chinese population has not been described thus far. Here, we report a case series of three patients with COXPD23 caused by GTPBP3 mutations, from a severe to a mild phenotype. The main clinical features of these patients include lactic acidosis, myocardial damage, and neurologic symptoms. Whole genome sequencing and targeted panels of candidate human mitochondrial genome revealed that patient 1 was a compound heterozygote with novel mutations c.413C > T (p. A138V) and c.509_510del (p. E170Gfs∗42) in GTPBP3. Patient 2 was a compound heterozygote with novel mutations c.544G > T (p. G182X) and c.785A > C (p.Q262P), while patient 3 was a compound heterozygote with a previously reported mutation c.424G > A (p.E142K) and novel mutation c.785A > C (p.Q262P). In conclusion, we first describe three Chinese individuals with COXPD23, and discuss the genotype-phenotype correlations of GTPBP3 mutations. Our findings provide novel information in the diagnosis and genetic counseling of patients with mitochondrial disease.

In this paper, the flexibility of bearing parts and localized defects are considered, and a method for calculating the radial time-varying stiffness of flexible cylindrical roller bearings (CRBs) with localized defects is proposed. The proposed method uses the finite element (FE) method to calculate the global flexibility of bearing parts and adopts the analytical contact theory to calculate the localized contact flexibility of bearing parts. Furthermore, based on the displacement excitation assumption, localized defect models of the outer race, inner race, and roller are established. The proposed method is verified by comparing with the methods in the references and the finite element method. The effect of different angles of defect width on time-varying stiffness is discussed. The results show that as the angle of defect width increases, the width of the stiffness saltation also gradually increases. Besides, the calculation accuracy of the proposed method is higher than that of the classical analytical method, and the computational efficiency is greatly improved compared with the finite element method. This study can provide a theoretical basis for defect diagnosis of CRBs.

We have previously demonstrated that anti-CD44s H4C4 or liposomal-delivered STAT3 inhibitor FLLL32 sensitized pancreatic cancer cells to radiotherapy through the elimination or inhibition of cancer stem cells (CSCs) and that HAb18G/CD147 promoted STAT3-mediated pancreatic tumor development by forming a signaling complex with CD44s. In this paper, we therefore explored whether anti-CD147 HAb18IgG sensitized pancreatic cancer cells to chemoradiotherapy via the targeting of CSCs. We tested the influence of HAb18IgG on the sensitivity of pancreatic cancer cells to chemoradiotherapy by clonogenic and MTT assays and on pancreatic CSCs by colony and sphere formation assays, flow cytometry, quantitative real-time RT-PCR (qRT-PCR) and stem cell transcription factors PCR array analysis. Changes in CD147 signaling were examined by immunoblot and reporter assays. We found that HAb18IgG sensitized pancreatic cancer cells to chemoradiotherapy by dose-dependently decreasing colony and sphere formation. Furthermore, HAb18IgG reduced the pancreatic CSC subpopulation and the expression of stem cell transcription factors OCT4, SOX2 and NANOG. Mechanistically, HAb18IgG inhibited CSCs by blocking CD44s-pSTAT3 signaling. The present findings indicated the promising therapeutic role of anti-CD147 HAb18IgG in suppressing pancreatic tumor initiation and overcoming post-chemoradiotherapy recurrence through the direct targeting of CSCs.

Four candidates of eclipsing multiples, based on new extraneous eclipses found on Kepler binary light curves, are presented and studied. KIC 7622486 is a double eclipsing binary candidate with orbital period of 2.2799960 days and 40.246503 days. The two binary systems do not eclipse each other in the line of sight, but there is mutual gravitational influence between them which leads to the small but definite eccentricity 0.0035(0.0022) on the short 2.2799960 days period orbit. KIC 7668648 is hierarchical quadruple system candidate, with two sets of solid 203(+-5) days period extraneous eclipses and another independent set of extraneous eclipses. A clear and credible extraneous eclipse is found on the binary light curve of KIC 7670485 which made it a triple system candidates. Two sets of extraneous eclipse of about 390 days and 220 days period are found on KIC 8938628 binary curves, which not only confirms the previous conclusion of $388.5(+-0.3) triple system, but also proposed a new additional objects that make KIC 8938628 a hierarchical quadruple system candidates. It is wished that the four candidates here will make some contributions to the field of eclipsing multiples., 16 pages, 7 figures

Satisfiability modulo theories (SMT) play a key role in verification applications. A crucial SMT problem is to combine separate theory solvers for the union of theories. In previous work, the simplex method is used to determine the solvability of constraint systems and the equalities implied by constraint systems are detected by a multitude of applications of the dual simplex method. We present an effective simplex tableau-based method to identify all implicit equalities such that the simplex method is harnessed to an irreducible minimum. Experimental results show that the method is feasible and effective.

For the truss structure composed of active-elements with piezoelectric patches affixed to its surface, taking the mechanical-electric coupling effect under the action of electric loads and mechanical loads into consideration, the finite element model for static force analysis is established by using the theory of mechanics. The failure mechanism of piezoelectric elements is discussed and the failure criteria of piezoelectric elements are proposed. The expression of safety margins for the element of piezoelectric truss structure is proposed with fracture strength, damage electric field strength, the section area of elements, and loads as random variables. On the basis of the research, the stochastic finite element method and structural reliability theory are used to analyze the reliability of the piezoelectric truss structure. An example is given to demonstrate the validity of this method.