Bearing multi-fault diagnosis with iterative generalized demodulation guided by enhanced rotational frequency matching under time-varying speed conditions.

The rotational frequency (RF) is an important information for multi-fault features detection of rolling bearing under varying speed conditions. In the traditional methods, such as the computed order analysis (COA) and the time-frequency analysis (TFA), the RF should be measured using an encoder or extracted by a complex algorithm, which bring challenge to bearing fault diagnosis. In order to address this issue, a novel iterative generalized demodulation (IGD) based method guided by the instantaneous fault characteristic frequency (IFCF) extraction and enhanced instantaneous rotational frequency (IRF) matching is proposed in this paper. Specifically, the resonance frequency band excited by bearing fault is first obtained by the band-pass filter, and its envelope time-frequency​ representation (TFR) is calculated using the Hilbert transform and the short-time Fourier transform (STFT). Second, the IFCF is extracted using the harmonic summation-based peak search algorithm from the envelope TFR. Third, the time-varying RF ridge is transformed into a line paralleling to the time axis using the IGD with the phase function (PF). The PF is calculated by the IFCF function and fault characteristic coefficient (FCC). Lastly, the iterative generalized demodulation spectrum (IGDS) is obtained using the fast Fourier transform (FFT) for identifying fault type corresponding to the extracted IFCF. Based on obtained fault type and FCC ratios, new PFs and frequency points (FPs) are calculated for detecting other faults. Both simulated and experimental results validate that multi-fault features of rolling bearing under time-varying rotational speeds can be effectively identified without RF measurement and extraction.

A Fault Detection Method for Electrohydraulic Switch Machine Based on Oil-Pressure-Signal-Sectionalized Feature Extraction.

A turnout switch machine is key equipment in a railway, and its fault condition has an enormous impact on the safety of train operation. Electrohydraulic switch machines are increasingly used in high-speed railways, and how to extract effective fault features from their working condition monitoring signal is a difficult problem. This paper focuses on the sectionalized feature extraction method of the oil pressure signal of the electrohydraulic switch machine and realizes the fault detection of the switch machine based on this method. First, the oil pressure signal is divided into three stages according to the working principle and action process of the switch machine, and multiple features of each stage are extracted. Then the max-relevance and min-redundancy (mRMR) algorithm is applied to select the effective features. Finally, the mini batch k-means method is used to achieve unsupervised fault diagnosis. Through experimental verification, this method can not only derive the best sectionalization mode and feature types of the oil pressure signal, but also achieve the fault diagnosis and the prediction of the status of the electrohydraulic switch machine.

Generative Adversarial Learning Enhanced Fault Diagnosis for Planetary Gearbox under Varying Working Conditions.

Planetary gearbox is a critical component for many mechanical systems. It is essential to monitor the planetary gearbox health and performance in order to maintain the whole machine works well. The methodology of mechanical fault diagnosis is increasingly intelligent with the extensive application of deep learning. However, the cross-domain issue caused by varying working conditions becomes an enormous encumbrance to fault diagnosis based on deep learning. In this paper, in order to fully excavate potentialities of deep neural network architectures, a novel generative adversarial learning method was introduced for a completely new fault diagnosis based on a deep convolution neural network. In addition, the intelligent fault diagnostic scheme for planetary gearbox under varying speed conditions was developed. After that, some experiments on measured vibration signals of planetary gearbox were conducted to verify the validity and efficiency of the fault diagnostic scheme. The results showed that the proposed method enhanced the capability of the intelligent diagnosis for planetary gear faults under varying speed conditions.

Downregulation of leaf flavin content induces early flowering and photoperiod gene expression in Arabidopsis.

BACKGROUND: Riboflavin is the precursor of flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), essential cofactors for many metabolic enzymes that catalyze a variety of biochemical reactions. Previously we showed that free flavin (riboflavin, FMN, and FAD) concentrations were decreased in leaves of transgenic Arabidopsis plants expressing a turtle riboflavin-binding protein (RfBP). Here, we report that flavin downregulation by RfBP induces the early flowering phenotype and enhances expression of floral promoting photoperiod genes. RESULTS: Early flowering was a serendipitous phenomenon and was prudently characterized as a constant phenotype of RfBP-expressing transgenic Arabidopsis plants in both long days and short days. The phenotype was eliminated when leaf free flavins were brought back to the steady-state levels either by the RfBP gene silencing and consequently nullified production of the RfBP protein, or by external riboflavin feeding treatment. RfBP-induced early flowering was correlated with enhanced expression of floral promoting photoperiod genes and the florigen gene FT in leaves but not related to genes assigned to vernalization, autonomous, and gibberellin pathways, which provide flowering regulation mechanisms alternative to the photoperiod. RfBP-induced early flowering was further correlated with increased expression of the FD gene encoding bZIP transcription factor FD essential for flowering time control and the floral meristem identity gene AP1 in the shoot apex. By contrast, the expression of FT and photoperiod genes in leaves and the expression of FD and AP1 in the shoot apex were no longer enhanced when the RfBP gene was silenced, RfBP protein production canceled, and flavin concentrations were elevated to the steady-state levels inside plant leaves. CONCLUSIONS: Token together, our results provide circumstantial evidence that downregulation of leaf flavin content by RfBP induces early flowering and coincident enhancements of genes that promote flowering through the photoperiod pathway.

Cancer/testis antigen HCA587-derived long peptide vaccine generates potent immunologic responses and antitumor effects in mouse model.

The cancer/testis antigen HCA587 (also known as MAGE-C2), one of the most immunogenic tumor antigens, is overexpressed in a wide spectrum of malignant tumors and can serve as a target for immunotherapy. In this study, we synthesized 14 overlapping (25-35 amino acids) long peptides representing the sequence of the most immunogenic part of the HCA587 protein and evaluated the antigen-specific immune responses and antitumor effects generated by immunization with the synthetic long peptide (SLP) vaccine in a mouse model. HCA587 SLPs in combination with adjuvants CFA and CpG ODN induced potent T-cell responses, which were dominated by type 1 cytokine IFN-γ-producing CD4(+) T cells as measured by ELISPOT and intracellular cytokine staining assay. Moreover, HCA587 SLP vaccination conferred protection against challenge with HCA587-expressing B16 melanoma in a therapeutic setting. Our findings may provide a scientific basis for the use of HCA587-derived long overlapping peptide vaccine for the treatment of patients with cancer in future clinical trials.

Induction of HCA587-specific antitumor immunity with HCA587 protein formulated with CpG and ISCOM in mice.

HCA587 (also known as MAGE-C2) is a "cancer-testis" antigen highly expressed in a number of malignancies with unique immunological properties, making it a promising target for tumor immunotherapy. In this report, we demonstrated that HCA587 protein, when formulated with adjuvants CpG-containing oligodeoxynucleotides (CpG ODN) and ISCOM, was capable of inducing a potent cellular and humoral immune response as indicated by the presence of a large number of HCA587-specific, IFN-γ-producing CD4(+) T cells and high levels of HCA587-specific antibodies. More importantly, vaccination with HCA587 conferred protection against challenge with HCA587-expressing B16 melanoma in prophylactic and therapeutic settings. In analysis of the mechanisms underlying the protective effect, we showed that the vaccination was followed by enhanced accumulation of tumor-infiltrating lymphocytes (TILs) with enrichment of conventional CD4(+) T cells but reduced representation of Treg cells. Further, the antitumor effect was largely abrogated in mice either depleted of CD4(+) T cells or deficient for IFN-γ. These results indicate that HCA587 protein vaccine possesses evident antitumor activity in a mouse model and holds promise for treatment of human cancers.

Identification of promiscuous HLA-DR-restricted CD4⁺ T-cell epitopes on the cancer-testis antigen HCA587.

The cancer testis antigen HCA587 is an attractive candidate for T cell-based immunotherapy because it is overexpressed in a wide spectrum of malignant tumors but not normal tissues, except testis. Several CTL epitopes derived from HCA587 have been described. Our aim was to identify helper T lymphocyte epitopes of HCA587 for the optimization of T cell-based immunotherapies against HCA587-expressing tumors. Candidate helper T lymphocyte epitopes for HCA587 were predicted using the SYFPEITHI algorithm and were tested for their ability to induce helper T lymphocyte responses by in vitro peptide vaccination of CD4(+) T lymphocytes from healthy individuals and hepatocellular carcinoma patients. Four CD4(+) T-cell epitopes for HCA587 (p43-57, p145-159, p186-200 and p249-263) were identified. Among them, the p43-57 epitope was shown to be naturally processed and presented by HCA587-expressing tumor cells as well as autologous dendritic cells pulsed with whole-protein HCA587. Notably, this epitope behaved as a promiscuous T-cell epitope as it stimulated T cells in the context of more than one HLA class II allele. Thus, p43-57 is the first HCA587-derived major histocompatibility complex class II-restricted epitope to fulfil all prerequisites for use as a peptide vaccine in patients with HCA587-expressing tumors.

A disposable organophosphorus pesticides enzyme biosensor based on magnetic composite nano-particles modified screen printed carbon electrode.

A disposable organophosphorus pesticides (OPs) enzyme biosensor based on magnetic composite nanoparticle-modified screen printed carbon electrodes (SPCE) has been developed. Firstly, an acetylcholinesterase (AChE)-coated Fe(3)O(4)/Au (GMP) magnetic nanoparticulate (GMP-AChE) was synthesized. Then, GMP-AChE was absorbed on the surface of a SPCE modified by carbon nanotubes (CNTs)/nano-ZrO(2)/prussian blue (PB)/Nafion (Nf) composite membrane by an external magnetic field. Thus, the biosensor (SPCE│CNTs/ZrO(2)/PB/Nf│GMP-AChE) for OPs was fabricated. The surface of the biosensor was characterized by scanning electron micrography (SEM) and X-ray fluorescence spectrometery (XRFS) and its electrochemical properties were studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The degree of inhibition (A%) of the AChE by OPs was determined by measuring the reduction current of the PB generated by the AChE-catalyzed hydrolysis of acetylthiocholine (ATCh). In pH = 7.5 KNO(3) solution, the A was related linearly to the concentration of dimethoate in the range from 1.0 × 10(-3)-10 ng · mL(-1) with a detection limit of 5.6 × 10(-4) ng · mL(-1). The recovery rates in Chinese cabbage exhibited a range of 88%-105%. The results were consistent with the standard gas chromatography (GC) method. Compared with other enzyme biosensors the proposed biosensor exhibited high sensitivity, good selectivity with disposable, low consumption of sample. In particular its surface can be easily renewed by removal of the magnet. The convenient, fast and sensitive voltammetric measurement opens new opportunities for OPs analysis.