231 research outputs found

    A Case Study of Assessing Button Bits Failure through Wavelet Transform Using Rock Drilling Induced Noise Signals

    Get PDF
    Finding the precise moment of button breakage of bits during drilling, with the experience of drill rig operators is a serious concern for modern vibrant mining industry. This research proposed a new methodology to find the failure of button using the sound generated by rock-bit interactions. The experiment is conducted by the video and sound data recorded during a drilling process in an underground mine, that uses a Sandvik AXERA7 twin boom jumbo drill rig and Polycrystalline diamond (PCD) tapered button bits. Signal analysis techniques such as Fourier transform and Wavelet transform are utilised to analyse the hectic noise signal recorded. The analysed results are shown that Wavelet Transform is much more effective in finding singularity points such as chipping or breakage of a button in compared to the Fourier Transform. The outcome of this analysis, which is the peak intensity at the breakage point, was correlated to the average intensity of the sound wave using moving average method. The results suggest that the noise generated during the drilling process can be used to detect the condition of the drill bit

    Bcl-2 protein family: Implications in vascular apoptosis and atherosclerosis

    Get PDF
    Apoptosis has been recognized as a central component in the pathogenesis of atherosclerosis, in addition to the other human pathologies such as cancer and diabetes. The pathophysiology of atherosclerosis is complex, involving both apoptosis and proliferation at different phases of its progression. Oxidative modification of lipids and inflammation differentially regulate the apoptotic and proliferative responses of vascular cells during progression of the atherosclerotic lesion. Bcl-2 proteins act as the major regulators of extrinsic and intrinsic apoptosis signalling pathways and more recently it has become evident that they mediate the apoptotic response of vascular cells in response to oxidation and inflammation either in a provocative or an inhibitory mode of action. Here we address Bcl-2 proteins as major therapeutic targets for the treatment of atherosclerosis and underscore the need for the novel preventive and therapeutic interventions against atherosclerosis, which should be designed in the light of molecular mechanisms regulating apoptosis of vascular cells in atherosclerotic lesions

    Positive Regulation by GABABR1 Subunit of Leptin Expression through Gene Transactivation in Adipocytes

    Get PDF
    Background: The view that c-aminobutyric acid (GABA) plays a functional role in non-neuronal tissues, in addition to an inhibitory neurotransmitter role in the mammalian central nervous system, is prevailing, while little attention has been paid to GABAergic signaling machineries expressed by adipocytes to date. In this study, we attempted to demonstrate the possible functional expression of GABAergic signaling machineries by adipocytes. Methodology/Principal Findings: GABAB receptor 1 (GABABR1) subunit was constitutively expressed by mouse embryonic fibroblasts differentiated into adipocytes and adipocytic 3T3-L1 cells in culture, as well as mouse white adipose tissue, with no responsiveness to GABA BR ligands. However, no prominent expression was seen with mRNA for GABA BR2 subunit required for heteromeric orchestration of the functional GABABR by any adipocytic cells and tissues. Leptin mRNA expression was significantly and selectively decreased in adipose tissue and embryonic fibroblasts, along with drastically reduced plasma leptin levels, in GABA BR1-null mice than in wild-type mice. Knockdown by siRNA of GABA BR1 subunit led to significant decreases in leptin promoter activity and leptin mRNA levels in 3T3-L1 cells. Conclusions/Significance: Our results indicate that GABABR1 subunit is constitutively expressed by adipocytes to primarily regulate leptin expression at the transcriptional level through a mechanism not relevant to the function as a partner o

    A Potassium Metal-Organic Framework based on Perylene- 3,4,9,10-tetracarboxylate as Sensing Layer for Humidity Actuators

    Get PDF
    We have synthesized a novel three-dimensional metal-organic-framework (MOF) based on the perylene-3,4,9,10-tetracarboxylate linker and potassium as metallic centre. We report the formation of this K-based MOF using conventional routes with water as solvent. This material displays intense green photoluminescence at room temperature, and displays an aggregation dependent quenching. Correlation of the optical properties with the crystalline packing was confirmed by DFT calculations. We also demonstrate its potential to build humidity actuators with a reversible and reproducible response, with a change of 5 orders of magnitudes in its impedance at about 40% relative humidity (RH). This 3D-MOF is based on an interesting perylene derivative octadentate ligand, a moiety with interesting fluorescent properties and known component in organic semiconductors. To the best of our knowledge, this is the first time to build such a printed and flexible actuator towards humidity with a reversible response, enabling precise humidity threshold monitoring.This work was supported by the Junta de Andalucía (FQM-1484, and FQM-195). Red Guipuzcoana de Ciencia, Tecnología e Innovación (OF188/2017) and University of the Basque Country (GIU14/01, EHUA16/32). BB acknowledges funding by RyC-2012–10381 contract and computational resources provided by the RES and Alhambra supercomputing facilities. This work was also supported by the German Research Foundation (DFG) and the Technical University of Munich within the Open Access Publishing Funding Programme

    An Earth-sized Planet around an M5 Dwarf Star at 22 pc

    Get PDF
    We report on the discovery of an Earth-sized transiting planet (R p = 1.015 ± 0.051 R ⊕) in a P = 4.02 day orbit around K2-415 (EPIC 211414619), an M5V star at 22 pc. The planet candidate was first identified by analyzing the light-curve data obtained by the K2 mission, and it is here shown to exist in the most recent data from TESS. Combining the light curves with the data secured by our follow-up observations, including high-resolution imaging and near-infrared spectroscopy with IRD, we rule out false-positive scenarios, finding a low false-positive probability of 2 × 10−4. Based on IRD’s radial velocities of K2-415, which were sparsely taken over three years, we obtain a planet mass of 3.0 ± 2.7 M ⊕ (M p < 7.5 M ⊕ at 95% confidence) for K2-415b. Being one of the lowest-mass stars (≈0.16 M ⊙) known to host an Earth-sized transiting planet, K2-415 will be an interesting target for further follow-up observations, including additional radial velocity monitoring and transit spectroscopy

    Genome Sequence of a Mesophilic Hydrogenotrophic Methanogen Methanocella paludicola, the First Cultivated Representative of the Order Methanocellales

    Get PDF
    We report complete genome sequence of a mesophilic hydrogenotrophic methanogen Methanocella paludicola, the first cultured representative of the order Methanocellales once recognized as an uncultured key archaeal group for methane emission in rice fields. The genome sequence of M. paludicola consists of a single circular chromosome of 2,957,635 bp containing 3004 protein-coding sequences (CDS). Genes for most of the functions known in the methanogenic archaea were identified, e.g. a full complement of hydrogenases and methanogenesis enzymes. The mixotrophic growth of M. paludicola was clarified by the genomic characterization and re-examined by the subsequent growth experiments. Comparative genome analysis with the previously reported genome sequence of RC-IMRE50, which was metagenomically reconstructed, demonstrated that about 70% of M. paludicola CDSs were genetically related with RC-IMRE50 CDSs. These CDSs included the genes involved in hydrogenotrophic methane production, incomplete TCA cycle, assimilatory sulfate reduction and so on. However, the genetic components for the carbon and nitrogen fixation and antioxidant system were different between the two Methanocellales genomes. The difference is likely associated with the physiological variability between M. paludicola and RC-IMRE50, further suggesting the genomic and physiological diversity of the Methanocellales methanogens. Comparative genome analysis among the previously determined methanogen genomes points to the genome-wide relatedness of the Methanocellales methanogens to the orders Methanosarcinales and Methanomicrobiales methanogens in terms of the genetic repertoire. Meanwhile, the unique evolutionary history of the Methanocellales methanogens is also traced in an aspect by the comparative genome analysis among the methanogens
    corecore