Remaining useful life estimation for deteriorating systems with time-varying operational conditions and condition-specific failure zones

AbstractDynamic time-varying operational conditions pose great challenge to the estimation of system remaining useful life (RUL) for the deteriorating systems. This paper presents a method based on probabilistic and stochastic approaches to estimate system RUL for periodically monitored degradation processes with dynamic time-varying operational conditions and condition-specific failure zones. The method assumes that the degradation rate is influenced by specific operational condition and moreover, the transition between different operational conditions plays the most important role in affecting the degradation process. These operational conditions are assumed to evolve as a discrete-time Markov chain (DTMC). The failure thresholds are also determined by specific operational conditions and described as different failure zones. The 2008 PHM Conference Challenge Data is utilized to illustrate our method, which contains mass sensory signals related to the degradation process of a commercial turbofan engine. The RUL estimation method using the sensor measurements of a single sensor was first developed, and then multiple vital sensors were selected through a particular optimization procedure in order to increase the prediction accuracy. The effectiveness and advantages of the proposed method are presented in a comparison with existing methods for the same dataset

Ovol1 regulates the growth arrest of embryonic epidermal progenitor cells and represses c-myc transcription

Transcriptional control plays a key role in regulating epidermal proliferation and differentiation. Although ample information has been obtained on how epidermal homeostasis is controlled in adult skin, less is known about the control of proliferation/differentiation of epidermal stem/progenitor cells in the developing embryo. Ovol1, encoding a zinc finger protein homologous to Drosophila melanogaster Ovo, is expressed in embryonic epidermal progenitor cells that are transiting from proliferation to terminal differentiation. In this study, we demonstrate a function for Ovol1 in interfollicular epidermal development. In its absence, developing epidermis fails to properly restrict the proliferative potential of progenitor cells, and cultured keratinocytes fail to efficiently undergo growth arrest in response to extrinsic growth-inhibitory signals. We present molecular evidence that c-myc expression is up-regulated in Ovol1-deficient suprabasal cells and that Ovol1 represses c-myc transcription by directly binding to its promoter. Collectively, our findings indicate that Ovol1 is required for proliferation exit of committed epidermal progenitor cells and identify c-myc as an Ovol1 target

Study on horizontal completion with composite tubular string in coal reservoir with complex coal structure

Aiming at the problems such as large deformation difference of coal structure, strong heterogeneity of physical properties, complex coal structure during horizontal drilling, single completion & stimulation technology and so on, a completion technology with composite tubular string for coalbed methane (CBM) horizontal well is proposed. Completion tools, inner operation tubing and outer completion string are designed. The outer completion string is composed of casing and screen pipe. The mechanics and hydraulics calculation model of dual tubular string are optimized. A field test of this completion technology had been accomplished in No. 15 coal seam in Yangquan, Shanxi Province, China. A dual tubular string of 659.5 m was run into the depth of 1591 m, and the horizonal well section in coal seam is divided into four sections by external casing packers (ECP). The tests of dual tubular string running, hydraulic circulation removing dual tubular string blocking and sticking, well washing, ECP expansion sealing and segmental completion in coal seam were accomplished. Based on the engineering data of this well, the force of dual tubular string was calculated by finite difference method, and the related hydraulic calculation was carried out. The results show that the inner tubing increases the lateral force of completion string, and the friction resistance on downhole tubular string increases by 5642.75 N. The pressure of completion tubular string is mainly affected by hydraulic loss of inner tubing and nozzles. The recommended displacement of hydraulic circulation is 16~20 L/s to remove rock and cuttings and maintain wellbore stability during completion string running. The displacement is increased to 20~24 L/s to eliminate the damage of drilling fluid to shaft wall during well washing operation. The research and field test verified the feasibility and innovation of the completion technology with composite tubular string for horizontal well, which provides a reliable basis for horizontal well diversified and adaptive stimulation in coal reservoir with complicated structure

Expression of MDR1, HIF-1α and MRP1 in sacral chordoma and chordoma cell line CM-319

<p>Abstract</p> <p>Background</p> <p>Chordoma was a typically slow-growing tumor. The therapeutic approach to chordoma had traditionally relied mainly on surgical therapy. And the main reason for therapeutic failure was resistance to chemotherapy and radiotherapy. However the refractory mechanism was not clear. The aim of this study was to investigate the expression of three genes (<it>MDR1</it>, <it>HIF-1α</it> and <it>MRP1</it>) associated with resistance to chemotherapy and radiotherapy in chordoma and chordoma cell line CM-319.</p> <p>Materials and methods</p> <p>Using immunohistochemical techniques, the expression of MDR1, HIF-1α and MRP1 was investigated in 50 chordoma specimen. Using RT-PCR and Western blot, the expression of MDR1, HIF-1α and MRP1 was investigated in chordoma and chordoma cell line CM-319.</p> <p>Results</p> <p>Expression of MDR1, HIF-1α and MRP1 was observed in 10%, 80% and 74% of all cases, respectively. Expression of MRP1 was correlated with HIF-1α. On the other hand, expression of MDR1 was not correlated with the expression of HIF-1α or MRP1. The expression of HIF-1α and MRP1 was observed, but MDR1 was not observed in chordoma and CM-319.</p> <p>Conclusion</p> <p>Expression of HIF-1α and MRP1 was observed in most chordoma specimen and CM-319 cell line; expression of HIF-1α correlated with MRP1. HIF-1α and MRP1 may play a role in the multidrug resistance of chordoma to chemotherapy.</p

The changes of T lymphocytes and cytokines in ICR mice fed with Fe3O4 magnetic nanoparticles

The aim of this article is to study the changes inhibited T lymphocytes and cytokines related to the cellular immunity in ICR (imprinting control region) mice fed with Fe3O4 magnetic nanoparticles (Fe3O4-MNPs). The Fe3O4-MNPs were synthesized, and their characteristics such as particle size, zeta potential, and X-ray diffraction patterns were measured and determined. All ICR mice were sacrificed after being exposed to 0, 300, 600, and 1200 mg/kg of Fe3O4-MNPs by single gastric administration for 14 days. Splenocytes proliferation was indicated with stimulate index by MTT assay; release of cytokines in the serum of ICR mice was detected by enzyme-linked immunosorbent assay, and the phenotypic analyses of T-lymphocyte subsets were performed using flow cytometry. Our results indicated that there were no significant differences in splenocyte proliferation and release of cytokines between exposed and control groups. Furthermore, there was no significant difference in the proportions of T-lymphocyte subsets in the low-dose Fe3O4-MNPs group when compared to the control group, but the proportions of CD3+CD4+ and CD3+CD8+ T-lymphocyte subsets both in the medium- and high-dose Fe3O4-MNPs groups were higher than those in the control group. It is concluded that a high dose of Fe3O4-MNPs, to some extent, could influence in vivo immune function of normal ICR mice

Identification of novel proteins interacting with vascular endothelial growth inhibitor 174 in renal cell carcinoma

Background/Aim: Vascular endothelial growth inhibitor (VEGI) is a multipotential cytokine that plays a role in regulating immunity, anti-angiogenesis, and inhibiting tumor growth. However, the proteins that interact with it are still unknown. In the present study, we examined the proteins which interact with VEGI174 and their expressions in renal cell carcinoma (RCC). Materials and Methods: The proteins that interact with VEGI174 were identified using western blot, pull-down assay, and mass spectrometry. The expressions of VEGI174 and the interacting proteins were examined in RCC and were compared with normal renal tissues using immunochemical staining and RNA-seq respectively. Results: The results of the mass spectrometric analysis showed that ACLY, ENO1, ZIK1, AKR1C3, and MYC may interact with VEGI174. When compared with the TCGA database, the expression level of VEGI174 in RCC was lower than that in normal kidney using RNAseq (p<0.001). The expression levels of ACLY, ENO1, ZIK1, AKR1C3 and MYC in RCC were higher than that in normal kidney (p<0.05, all of above factors). Moreover, immunochemical staining results also showed that the expression level of AKR1C3 in RCC was significantly higher than that in normal kidney (p<0.001) and was also positively correlated with higher RCC stage and grade. Conclusion: Taken together, our findings showed that VEGI174 may interact with ACLY, ENO1, ZIK1, AKR1C3, and MYC. The expression of ACLY, ENO1, AKR1C3 and MYC is increased in RCC. AKR1C3 was a new factor that may correlate with the progression of RCC. The results indicated that VEGI174 has more functions than we currently know in the development and progression of RC

High CRLF2 expression associates with IKZF1 dysfunction in adult acute lymphoblastic leukemia without CRLF2 rearrangement.

Overexpression of cytokine receptor-like factor 2 (CRLF2) due to chromosomal rearrangement has been observed in acute lymphoblastic leukemia (ALL) and reported to contribute to oncogenesis and unfavorable outcome in ALL. We studied B-ALL and T-ALL patients without CRLF2 rearrangement and observed that CRLF2 is significantly increased in a subset of these patients. Our study shows that high CRLF2expression correlates with high-risk ALL markers, as well as poor survival. We found that the IKZF1-encoded protein, Ikaros, directly binds to the CRLF2 promoter and regulates CRLF2 expression in leukemia cells. CK2 inhibitor, which can increase Ikaros activity, significantly increases Ikaros binding in ALL cells and suppresses CRLF2 expression in an Ikaros-dependent manner. CRLF2 expression is significantly higher in patients with IKZF1 deletion as compared to patients without IKZF1 deletion. Treatment with CK2 inhibitor also results in an increase in IKZF1 binding to the CRLF2 promoter and suppression of CRLF2 expression in primary ALL cells. We further observed that CK2 inhibitor induces increased H3K9me3 histone modifications in the CRLF2 promoter in ALL cell lines and primary cells. Taken together, our results demonstrate that high expression of CRLF2 correlates with high-risk ALL and short survival in patients without CRLF2 rearrangement. Our results are the first to demonstrate that the IKZF1-encoded Ikaros protein directly suppresses CRLF2 expression through enrichment of H3K9me3 in its promoter region. Our data also suggest that high CRLF2 expression works with the IKZF1 deletion to drive oncogenesis of ALL and has significance in an integrated prognostic model for adult high-risk ALL