Vaccine Types

There are several different types of vaccines. Each type is designed to teach your immune system how to fight off certain kinds of germs and the serious diseases they cause. There are four main types of vaccines: live attenuated vaccines; inactivated vaccines; subunit, recombinant, polysaccharide, and conjugate vaccines; and toxoid vaccines

Nonlinear dynamic behaviors of rotated blades with small breathing cracks based on vibration power flow analysis

Rotated blades are key mechanical components in turbomachinery and high cycle fatigues often induce blade cracks. Accurate detection of small cracks in rotated blades is very significant for safety, reliability, and availability. In nature, a breathing crack model is fit for a small crack in a rotated blade rather than other models. However, traditional vibration displacements-based methods are less sensitive to nonlinear characteristics due to small breathing cracks. In order to solve this problem, vibration power flow analysis (VPFA) is proposed to analyze nonlinear dynamic behaviors of rotated blades with small breathing cracks in this paper. Firstly, local flexibility due to a crack is derived and then time-varying dynamic model of the rotated blade with a small breathing crack is built. Based on it, the corresponding vibration power flow model is presented. Finally, VPFA-based numerical simulations are done to validate nonlinear behaviors of the cracked blade. The results demonstrate that nonlinear behaviors of a crack can be enhanced by power flow analysis and VPFA is more sensitive to a small breathing crack than displacements-based vibration analysis. Bifurcations will occur due to breathing cracks and subharmonic resonance factors can be defined to identify breathing cracks. Thus the proposed method can provide a promising way for detecting and predicting small breathing cracks in rotated blades

The study of GPX3 methylation in patients with Kashin-Beck Disease and its mechanism in chondrocyte apoptosis

Objective Selenium deficiency is a risk factor for Kashin-Beck Disease (KBD), an endemic osteoarthropathy. Although promoter hypermethylation of glutathione peroxidase 3 (GPX3) (a selenoprotein) has been identified in several cancers, little is known about promoter methylation and expression of GPX3 and their relation to selenium in KBD. The present study was thus conducted to investigate this research question. Methods Methylation and expressions of GPX3 in whole blood drawn from 288 KBD patients and 362 healthy controls and in chondrocyte cell line were evaluated using methylation-specific PCR and qRT-PCR, respectively. The protein levels of PI3K/Akt/c-fos signaling in the whole blood and chondrocyte cell line were determined with Western blotting. Chondrocytes apoptosis were detected by Hoechst 33342 and Annexin V-FITC/PI staining. Results GPX3 methylation was increased, GPX3 mRNA was decreased, and protein levels in the PI3K/Akt/c-fos signaling pathway were up-regulated in the whole blood collected from KBD patients as compared with healthy controls. Similar results were obtained for chondrocytes injured by oxidative stress. There was a significant, decreasing trend in GPX3 expression across groups of unmethylation, partial methylation, and complete methylation for GPX3, in sequence. Compared with unmethylation group, protein levels in PI3K/Akt/c-fos pathway were enhanced in partial and complete methylation groups. Treatment of chondrocytes with sodium selenite resulted in reduced methylation and increased expression of GPX3 as well as down-regulated level of PI3K/Akt/c-fos proteins. Conclusions The methylation and expression of GPX3 and expression of PI3K/Akt/c-fos pathway are altered in KBD and these changes are reversible by selenium supplementation

The CD25+/CD4+ T cell ratio and levels of CII, CIX and CXI antibodies in serum may serve as biomarkers of pristane-induced arthritis in rats and Rheumatoid Arthritis in humans

Collagen antibodies in serum are involved in the pathogenesis of Rheumatoid Arthritis (RA). The objective of this study was to identify the subtype of collagen antibodies and T cell subtype distribution in pristane-induced arthritis (PIA) and to clarify their roles in the initiation and maintenance of arthritis.Arthritis was induced in Dark Agouti (DA) rats by injection of pristane. The severity was evaluated by macroscopic and microscopic score systems. The alteration of CD25+/CD4+ T cell ratio in rats was detected by flow cytometry. Collagen type II (CII), CIX, or CXI antibody in serum was determined by ELISA. The levels of Nitric oxide (NO) and tartrate-resistant acid phosphatase (TRAP) were measured by kits.The serum levels of CII, CIX, CXI antibodies were significantly increased in RA patients while slightly increased in PIA rats. The ratio of CD25+/CD4+ T cells was significantly higher in RA rats than that in the control group. The serum levels of NO and TRAP in PIA rats and RA patients were higher than that in the control groups, which suggested that the activity of osteoclast was increased in RA.The ratio of CD25+/CD4+ T cells plays a pivotal role in the development of PIA. The serum levels of NO and TRAP are inflammatory and osteoclast activity indicators. The serum levels of CII, CIX and CXI antibodies may serve as the clinical diagnostic indicators. These findings are important to our understanding of the pathogenesis of RA, and may provide biomarkers of RA diagnosis and therapeutic targets for the treatment of RA

Nonlinear Dynamic Behaviors of Rotated Blades with Small Breathing Cracks Based on Vibration Power Flow Analysis

Rotated blades are key mechanical components in turbomachinery and high cycle fatigues often induce blade cracks. Accurate detection of small cracks in rotated blades is very significant for safety, reliability, and availability. In nature, a breathing crack model is fit for a small crack in a rotated blade rather than other models. However, traditional vibration displacements-based methods are less sensitive to nonlinear characteristics due to small breathing cracks. In order to solve this problem, vibration power flow analysis (VPFA) is proposed to analyze nonlinear dynamic behaviors of rotated blades with small breathing cracks in this paper. Firstly, local flexibility due to a crack is derived and then time-varying dynamic model of the rotated blade with a small breathing crack is built. Based on it, the corresponding vibration power flow model is presented. Finally, VPFA-based numerical simulations are done to validate nonlinear behaviors of the cracked blade. The results demonstrate that nonlinear behaviors of a crack can be enhanced by power flow analysis and VPFA is more sensitive to a small breathing crack than displacements-based vibration analysis. Bifurcations will occur due to breathing cracks and subharmonic resonance factors can be defined to identify breathing cracks. Thus the proposed method can provide a promising way for detecting and predicting small breathing cracks in rotated blades

Melnikov method-based broadband mechanisms and necessary conditions of nonlinear rotating energy harvesting using piezoelectric beam

Nonlinearity can be used to enhance broadband rotating piezoelectric vibration energy harvesting, but how to construct a proper nonlinear rotating harvester is a challenging problem in engineering applications. This article presents a Melnikov-theory-based method to explore broadband mechanism and necessary conditions of nonlinear rotating piezoelectric vibration energy harvesting system. First, a perturbed state-space representation of nonlinear rotating energy harvesting system is built based on its dynamic model. It can be seen that bi-stability of the unperturbed nonlinear system is the physical basis of achieving broadband and low-frequency rotating energy harvesting. Second, the Melnikov function is defined to derive two necessary conditions of homoclinic bifurcation and chaotic motions. Then simulations are performed to identify the key parameters and their effects on the Melnikov conditions, including distance, rotating frequency, and excitations. It can be seen that homoclinic bifurcation and chaotic motions can occur in nonlinear rotating energy harvesting systems under single-frequency and broadband excitations. Finally, the experiments are carried out to validate the two necessary conditions. The results demonstrate that the proposed method can provide important guidelines for optimally designing nonlinear rotating piezoelectric energy harvesters in practice

A high-efficiency, self-powered nonlinear interface circuit for bi-stable rotating piezoelectric vibration energy harvesting with nonlinear magnetic force

Parallel synchronized switch harvesting on inductor (P-SSHI) circuits have been proved to enhance piezoelectric vibration energy harvesting (PVEH), but the maximum conversion efficiency is obtained only when the voltage across the storage capacitor (VSC) equates to the optimal value. For bi-stable rotating PVEH with nonlinear magnetic force in engineering applications, however, the VSC will change greatly when powering real electric loads, thus it is impossible to maintain high conversion efficiency. In order to solve this problem, this paper presents an improved P-SSHI circuit with controllable optimal voltage (COV-PSSHI) by using a voltage control strategy between the storage capacitor and the electric load. The innovation is to control and maintain the VSC close to the optimal value. Firstly, the COV-PSSHI circuit is proposed and its theoretic model is built in detail. Then its average harvested power (AHP) is theoretically derived and AHP of the COV-PSSHI circuit is proved to be more than that of a classical P-SSHI circuit. In the end, experiments are performed to validate the performance of the COV-PSSHI circuit. It can be seen that the COV-PSSHI circuit can increase the AHP by factor 1.25 compared with classical P-SSHI circuits, which is enough to intermittently power the wireless sensor node. Also power consumption of the voltage control circuit has few effects on the COV-PSSHI circuit. In particular, it needs to optimize the envelop capacitor, the parallel inductor and two threshold voltages of the voltage controller in order to implement the COV-PSSHI circuit well in practice

Strain-modulated photoelectric responses from a flexible α-In₂Se₃/3R MoS₂ heterojunction

Semiconducting piezoelectric α-In2Se3 and 3R MoS2 have attracted tremendous attention due to their unique electronic properties. Artificial van der Waals (vdWs) heterostructures constructed with α-In2Se3 and 3R MoS2 flakes have shown promising applications in optoelectronics and photocatalysis. Here, we present the first flexible α-In2Se3/3R MoS2 vdWs p-n heterojunction devices for photodetection from the visible to near infrared region. These heterojunction devices exhibit an ultrahigh photoresponsivity of 2.9 × 103 A W-1 and a substantial specific detectivity of 6.2 × 1010 Jones under a compressive strain of - 0.26%. The photocurrent can be increased by 64% under a tensile strain of + 0.35%, due to the heterojunction energy band modulation by piezoelectric polarization charges at the heterojunction interface. This work demonstrates a feasible approach to enhancement of α-In2Se3/3R MoS2 photoelectric response through an appropriate mechanical stimulus.Agency for Science, Technology and Research (A*STAR)Ministry of Education (MOE)Published versionThis project is financially supported by MOE AcRF Tier2 (2018-T2-2-005), MOE AcRF Tier1 (2018- T1-005-001) and A*STAR AME IRG Grant SERC A1983c0027, Singapore

Identification of differentially expressed and methylated genes associated with rheumatoid arthritis based on network

Rheumatoid arthritis (RA) is a multi-systemic inflammatory autoimmune disease involving peripheral joints, and the pathogenesis is not clear. Studies showed that DNA methylation and expression might also be involved in the pathogenesis of RA. This study integrated three expression profile datasets (GSE55235, GSE12021, and GSE55457) and one methylation profile dataset GSE111942 to elucidate the potential essential candidate genes and pathways in RA. Differentially expressed genes (DEGs) and differentially methylation genes (DMGs) were identified by R programming software, using Limma package and ChAMP package, respectively. DAVID performed gene Ontology (GO) and Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathway enrichment analysis of DEGs. Functional annotation and construction of a protein–protein interaction (PPI) network and the Molecular Complex Detection Algorithm (MCODE) were analysed by STRING and Cystoscope, respectively. Then the connection analysis of DEGs and DMGs was carried out, and further to analyse the relationship between methylation and gene expression, aiming to screen out the potential genes. In this study, 288 DEGs and 228 DMGs were identified, and the majority of DEGs were up-regulated. Enrichment analysis represented that DEGs mainly involved immune response and participated in the Cytokine–cytokine receptor interaction signal pathway. 282 nodes were identified from DEGs PPI network and MCODE, filtering the most significant 2 modules, 23 core node genes were identified and most of them are involved in the T cell receptor signalling pathway and chemokine-mediated signalling pathway. Cross-analysis revealed 4 genes [KNTC1 (cg 01277763), LRRC8D (cg 07600884), DHRS9 (cg 05961700), and UCP2 (cg 05205664)] that exhibited differential expression and methylation in RA simultaneously. Therefore, the four genes could be used as the target for RA