ALBERT

Description: Under the strong noise environment, the composite fault signal of gearbox is weak, which makes it difficult to extract fault features. For this problem, based on noise-assisted method, we propose a novel method called Modified Singular Spectrum Decomposition (MSSD). Singular Spectrum Decomposition (SSD) has many advantages such as high decomposition precision and strong ability to restrain mode mixing, etc. However, the ability of SSD to extract a weak signal is not ideal, the decomposition results usually contain a lot of redundant noise and mode mixing caused by intermittency, which is also a troubling problem. In order to improve the decomposition efficiency and make up for the defects of SSD, the new method MSSD adds an adaptive and particular noise in every SSD decomposition stage for each trial, and in addition, whenever the input signal is decomposed to obtain an intrinsic module function (IMF), a unique residual is obtained. After multiple decomposition, the average value of the residual is used as input to the next stage, until the residual cannot continue to decompose, which means that the residual component has, at most, one extreme value. Finally, analyzing simulated signals to explain the advantages of MSSD compared to ensemble empirical mode decomposition (EEMD) and complete ensemble local mean decomposition with adaptive noise (CEEMDAN). In order to further prove the effectiveness of MSSD, this new method, MSSD, is applied to the fault diagnosis of an engineering gearbox test stand in an actual engineer project case. The final results show that MSSD can extract more fault feature information, and mode mixing has been improved and suffers less interference compared to SSD.

Description: Aiming at the problem that the composite fault signal of the gearbox is weak and the fault characteristics are difficult to extract under strong noise environment, an improved singular spectrum decomposition (ISSD) method is proposed to extract the composite fault characteristics of the gearbox. Singular spectrum decomposition (SSD) has been proved to have higher decomposition accuracy and can better suppress modal mixing and pseudo component. However, noise has a great influence on it, and it is difficult to extract weak impact components. In order to improve the limitations of SSD, we chose the minimum entropy deconvolution adjustment (MEDA) as the pre-filter of the SSD to preprocess the signal. The main function of the minimum entropy deconvolution adjustment is to reduce noise and enhance the impact component, which can make up for the limitations of SSD. However, the ability of MEDA to reduce noise and enhance the impact signal is greatly affected by its parameter, the filter length. Therefore, to improve the shortcomings of MEDA, a parameter adaptive method based on Cuckoo Search (CS) is proposed. First, construct the objective function as the adaptive function of CS to optimize the MEDA algorithm. Then, the pre-processed signal is decomposed into singular spectral components (SSC) by SSD, and the meaningful components are selected by Correlation coefficient. For the existing modal mixing phenomenon, the SSC component is reconstructed to eliminate the misjudgment of the result. Then, the frequency spectrum analysis is performed to obtain the frequency information for fault diagnosis. Finally, the effectiveness and superiority of ISSD are validated by simulation signals and applying to compound faults of a Gear box test rig.

Description: Energies, Vol. 11, Pages 2233: Deformation, Permeability and Acoustic Emission Characteristics of Coal Masses under Mining-Induced Stress Paths Energies doi: 10.3390/en11092233 Authors: Yi Xue Faning Dang Zhengzheng Cao Feng Du Jie Ren Xu Chang Feng Gao The geomechanical and seepage evolution characteristics of coal masses during mining are the key factors that affect the drainage of coalbed methane and the safety of coal mining. Nevertheless, the influence of mining paths on coal seam permeability is rarely investigated given the complexity of mining-induced stress experiments. To study the effect of mining-induced stress on coal mining, the mechanical properties, acoustic emission characteristics and energy evolution of coal masses were experimentally evaluated through mining-induced stress experiments. Experimental results indicated that at peak intensity, the deviatoric stress and axial strain of coal samples under the stress path of protective coal-seam mining are lower than those of coal samples under the non-pillar stress path. The unloading ratio of confining pressure is large under a stress path of non-pillar mining, and the elastic energy, the absorbed energy, and the dissipated energy of coal mass are low during destruction. The effect of high confining pressure on AE events is pronounced under the non-pillar mining path. The overall b value under high confining pressure is smaller than that under low confining pressure, and AE events generally have high energy. The fracture structure of coal mass is complex, and the fractal size of coal is large under high unloading rates of confining pressure, which induce the increase of permeability after coal destruction.

Description: Herein we described a deoxyribonucleic acid (DNA) calculator for sensitive detection of the determination of adenosine triphosphate (ATP) using gold nanoparticles (GNP) and PicoGreen fluorescence dye as signal transducer, and ATP and single-stranded DNA (DNA-M′) as activators. The calculator-related performances including linearity, reaction time, logic gate, and selectivity were investigated, respectively. The results revealed that this oligonucleotide sensor was highly sensitive and selective. The detection range was 50–500 nmol/L (R2 = 0.99391) and the detection limit was 46.5 nmol/L. The AND DNA calculator was successfully used for the ATP detection in human urine. Compared with other methods, this DNA calculator has the characteristics of being label-free, non-enzymic, simple, and highly sensitive.

Description: Graft-versus-host disease (GVHD) remains the major cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation (HSCT). Impaired mucosal epithelial barrier contributes significantly to amplifying systemic inflammatory responses characteristic of GVHD. Emerging evidence demonstrates that protecting or restoring intestinal barrier function represents a feasible approach to mitigate GVHD. There is growing interest in how vitamin D and the vitamin D receptor (VDR) signaling regulate immune responses in intestinal inflammatory diseases. The role of VDR signaling in regulating alloimmunity is unknown. We therefore tested the novel hypothesis that VDR signaling plays an important role in maintaining intestinal epithelial barrier function during GVHD. In initial studies, we examined whether intestinal VDR signaling is altered in recipient mice undergoing either syngeneic or allogeneic bone marrow transplantation (BMT). We found a progressive decline in VDR gene expression over time in colon tissues of allogeneic, but not syngeneic, BMT recipients compared with that of naïve animals. Notably, the expression of CYP27B1, the key enzyme participating in the biosynthesis of the active form of vitamin D, 1α,25-dihydroxyvitamin D3 (1,25VitD3), was also significantly decreased in the intestines of allogeneic BMT recipients compared to that of naïve animals. Caco-2 is an epithelial cell line that is widely used as a model for the intestinal barrier. We showed that proinflammatory cytokines TNF-α and IL-6 reduced Caco-2 VDR protein levels in a dose and time dependent manner by western blot analysis. To assess monolayer barrier function, an in vitro permeability assay was performed using FITC-dextran. We found 1,25VitD3 significantly attenuated the increase in epithelial monolayer permeability induced by TNF-α and IL-6. Tight junctions are important components of the intestinal barrier. We also found proinflammatory cytokines reduced gene expression of tight junctions such as occludin in Caco-2 cells. Remarkably, 1,25VitD3 treatment significantly restored occludin expression. We then examined how vitamin D/VDR pathway regulates the development of GVHD. 1,25VitD3 supplementation after BMT significantly increased the survival of recipient mice in a well-established C57Bl/6→Balb/c GVHD model (p=0.0045). 1,25VitD3 treatment did not appear to modify donor T cell alloreactivity. Specifically, donor T cell activation, proliferation, and polarization were not affected by 1,25VitD3 treatment. Notably, infusion of donor T cells from VDR-WT (VDR+/+) or VDR-deficient (VDR-/-) mice caused similar GVHD-associated mortality in Balb/c recipient mice (p=0.98), further suggesting that the beneficial effects of 1,25VitD3 treatment is not due to its effects on donor T cells. 1,25VitD3 also did not appear to affect host and donor antigen presenting cells to modulate GVHD severity. Specifically, dendritic cells from VDR+/+ or VDR-/- mice showed equal ability to stimulate the proliferation of alloreactive T cells in mixed lymphocyte reactions. There was also no difference in post-transplant survival when recipient mice were reconstituted with donor T-cell-depleted bone marrow cells from either VDR+/+ or VDR-/- mice (recipients were transplanted with the same donor T cells from VDR-WT animals; p=0.58). Instead, 1,25VitD3 treatment significantly increased tight junction protein expression in the gut, suggesting its effect on intestinal epithelial cells. Finally, transgenic mice selectively overexpress VDR in the intestinal epithelium (villin promoter-driven FLAG-tagged human VDR gene expression) were used as BMT recipients in gain-of-function studies. We found a significantly decreased GVHD-associated mortality in these mice compared to that of control littermates (p=0.0002), providing direct evidence that intestinal epithelial VDR signaling protects against GVHD. Our results provide new evidence supporting the notion that impaired mucosal barrier function is a major pathogenic factor in the development of GVHD. Intestinal VDR signaling plays an important role in maintaining intestinal barrier integrity and enhancing this pathway protects against GVHD. Thus, our study provides pre-clinical data supporting the use of vitamin D or its analogs as a simple and inexpensive therapeutic modality with minimal side effects for mitigating GVHD. Disclosures No relevant conflicts of interest to declare.

Description: With the simple functionalization method and good biocompatibility, an aptamer-integrated DNA hydrogel is used as the protein delivery system with an adjustable release rate and time by using complementary sequences (CSs) as the biomolecular trigger. The aptamer-functionalized DNA hydrogel was prepared via a one-pot self-assembly process from two kinds of DNA building blocks (X-shaped and L-shaped DNA units) and a single-stranded aptamer. The gelling process was achieved under physiological conditions within one minute. In the absence of the triggering CSs, the aptamer grafted in the hydrogel exhibited a stable state for protein-specific capture. While hybridizing with the triggering CSs, the aptamer is turned into a double-stranded structure, resulting in the fast dissociation of protein with a wise-stage controlled release program. Further, the DNA hydrogel with excellent cytocompatibility has been successfully applied to human serum, forming a complex matrix. The whole process of protein capture and release were biocompatible and could not refer to any adverse factor of the protein or cells. Thus, the aptamer-functionalized DNA hydrogel will be a good candidate for controlled protein delivery.