Numerical investigation on sand erosion phenomenon of coated and uncoated vanes in low-pressure gas turbine

For energy saving and less environmental impact, efficient energy utilization is of importance. In a gas-turbine engine, its performance increases as increasing temperature of the turbine inlet flow. However, turbine components are required to be protected from the high temperature flows. Recently, ceramic matrix composite (referred as CMC, hereafter) is expected to be utilized as protecting the gas-turbine components due to the excellent properties of CMC in high temperature conditions: low density, high strength and high rigidity. Therefore, the CMC allows us to increase the inlet temperature and leads to high performance of gas-turbine engines. On the other hand, sand erosion phenomenon is one of serious problems in gas-turbine engines. Sand particles ingested from the engine inlet impinge and erode the wall surfaces, which can cause engine failure. In order to prevent the sand erosion phenomenon, anti-erosion coatings have been developed and adopted for gas-turbines, although the anti-erosion characteristics of the CMC coating have not completely been clarified. The objective of the present paper is to perform numerical simulations of sand erosion phenomenon on the coated and the uncoated T106 CMC vanes in a low-pressure gas turbine. We investigate the flow field, particle trajectories and the eroded shape of the CMC turbine vanes. The results show that the erosion occurs near the leading edge and at the 90 percent axial chord on the pressure surface in both of the coated and uncoated cases. In the uncoated case, the severe erosion phenomenon is observed especially. Accordingly, we have concluded that the coating obviously played an important role in protecting the CMC vanes from sand erosion

Visualization of pilot flame of an optically-accessible coaxially-staged aero-engine lean-burn fuel injector

[EN] The visualization of the pilot flame of a coaxially-staged aero-engine lean-burn fuel injector, not only downstream but also inside of the pilot nozzle, was successfully performed at realistic aero-engine conditions. Optical access toward the inside of the nozzle was achieved through the inner and outer shrouds, both of which were made of transparent quartz. The image distortion caused by complex contours of the two shrouds was corrected by a method based on optical ray tracing, which realized precise determination of spatial intensity distribution of optical signals. Line-of-sight OH chemiluminescence, cross-sectional OH-LIF, kerosene LIF and kerosene Mie scattering were employed as diagnostic tools. The effects of pilot local air-to-fuel ratio on spray flame structure were revealed, both inside and downstream of the pilot nozzle under stable combustions. As the pilot mixture got rich, the main reaction zone moved from inside of the pilot nozzle to the region near the injector lip downstream of the injector exit. The OH-LIF signal was detected near the central axis surrounded by the fuel spray. It was also observed near the back-step of the pilot nozzle for the rich cases. The experiments under combustion oscillation were also conducted and the correlation of phenomena inside and downstream of the pilot nozzle was captured. It was clarified that the reaction enhancement in the outer part of the lip vortex region was caused by the convection of rich mixture, which appeared near the pilot atomizer lip at 150~210deg earlier oscillation phase angle.Matsuura, K.; Uesaka, S.; Iwasaki, T.; Kurosawa, Y.; Yamada, H.; Yamamoto, T.; Hayashi, S. (2017). Visualization of pilot flame of an optically-accessible coaxially-staged aero-engine lean-burn fuel injector. En Ilass Europe. 28th european conference on Liquid Atomization and Spray Systems. Editorial Universitat Politècnica de València. 855-872. https://doi.org/10.4995/ILASS2017.2017.475285587

Cubic lead perovskite PbMoO3 with anomalous metallic behavior

A previously unreported Pb-based perovskite PbMoO$_3$ is obtained by high-pressure and high-temperature synthesis. This material crystallizes in the $Pm\bar{3}m$ cubic structure at room temperature, making it distinct from typical Pb-based perovskite oxides with a structural distortion. PbMoO$_3$ exhibits a metallic behavior down to 0.1 K with an unusual $T$-sub linear dependence of the electrical resistivity. Moreover, a large specific heat is observed at low temperatures accompanied by a peak in $C_P/T^3$ around 10 K, in marked contrast to the isostructural metallic system SrMoO$_3$. These transport and thermal properties for PbMoO$_3$, taking into account anomalously large Pb atomic displacements detected through diffraction experiments, are attributed to a low-energy vibrational mode, associated with incoherent off-centering of lone pair Pb$^{2+}$ cations. We discuss the unusual behavior of the electrical resistivity in terms of a polaron-like conduction, mediated by the strong coupling between conduction electrons and optical phonons of the local low-energy vibrational mode.Comment: 5 pages, 5 figure

The aim of the measurement of Epstein‐Barr virus DNA in hydroa vacciniforme and hypersensitivity to mosquito bites

Epstein‐Barr virus (EBV) DNA load in the blood increases in posttransplant lymphoproliferative disorders and chronic active EBV infection. In this report, we analyzed the EBV DNA load in the peripheral blood mononuclear cells (PBMCs) and plasma of patients with hydroa vacciniforme (HV) and/or hypersensitivity to mosquito bites (HMB) to understand the clinical significance of EBV DNA load. All 30 patients showed high DNA loads in the PBMCs over the cut‐off level. Of 16 plasma samples, extremely high in two samples obtained from patients with hemophagocytic lymphohistiocytosis (HLH). The amount of cell‐free DNA in plasma was correlated to the serum levels of lactate dehydrogenase and inversely correlated to platelet counts. These results indicate that the EBV DNA load in PBMCs can provide one of the diagnostic indicators for HV and HMB and marked elevation of cell‐free EBV DNA in plasma might be related to cytolysis such as that observed in HLH

The spatiotemporal expression of multiple coho salmon ovarian connexin genes and their hormonal regulation in vitro during oogenesis

BACKGROUND: Throughout oogenesis, cell-cell communication via gap junctions (GJs) between oocytes and surrounding follicle cells (theca and granulosa cells), and/or amongst follicle cells is required for successful follicular development. To gain a fundamental understanding of ovarian GJs in teleosts, gene transcripts encoding GJ proteins, connexins (cx), were identified in the coho salmon, Oncorhynchus kisutch, ovary. The spatiotemporal expression of four ovarian cx transcripts was assessed, as well as their potential regulation by follicle-stimulating hormone (FSH), luteinizing hormone (LH) and insulin-like growth factor 1 (IGF1). METHODS: Salmonid ovarian transcriptomes were mined for cx genes. Four gene transcripts designated cx30.9, cx34.3, cx43.2, and cx44.9 were identified. Changes in gene expression across major stages of oogenesis were determined with real-time, quantitative RT-PCR (qPCR) and cx transcripts were localized to specific ovary cell-types by in situ hybridization. Further, salmon ovarian follicles were cultured with various concentrations of FSH, LH and IGF1 and effects of each hormone on cx gene expression were determined by qPCR. RESULTS: Transcripts for cx30.9 and cx44.9 were highly expressed at the perinucleolus (PN)-stage and decreased thereafter. In contrast, transcripts for cx34.3 and cx43.2 were low at the PN-stage and increased during later stages of oogenesis, peaking at the mid vitellogenic (VIT)-stage and maturing (MAT)-stage, respectively. In situ hybridization revealed that transcripts for cx34.3 were only detected in granulosa cells, but other cx transcripts were detected in both oocytes and follicle cells. Transcripts for cx30.9 and cx44.9 were down-regulated by FSH and IGF1 at the lipid droplet (LD)-stage, whereas transcripts for cx34.3 were up-regulated by FSH and IGF1 at the LD-stage, and LH and IGF1 at the late VIT-stage. Transcripts for cx43.2 were down-regulated by IGF1 at the late VIT-stage and showed no response to gonadotropins. CONCLUSION: Our findings demonstrate the presence and hormonal regulation of four different cx transcripts in the salmon ovary. Differences in the spatiotemporal expression profile and hormonal regulation of these cx transcripts likely relate to their different roles during ovarian follicle differentiation and development

The duplicated Y-specific amhy gene is conserved and linked to maleness in silversides of the genus Odontesthes

Sex-determining genes have been successively isolated in several teleosts. In Odontesthes hatcheri and O. bonariensis, the amhy gene has been identified as a master sex-determining gene. However, whether this gene is conserved along related species is still unknown. In this study, the presence of amhy and its association with phenotypic sex was analyzed in 10 species of Odontesthes genus. The primer sets from O. hatcheri that amplify both amhs successfully generated fragments that correspond to amha and amhy in all species. The full sequences of amhy and amha isolated for four key species revealed higher identity values among presumptive amhy, including the 0.5 Kbp insertion in the third intron and amhy-specific insertions/deletions. Amha was present in all specimens, regardless of species and sex, whereas amhy was amplified in most but not all phenotypic males. Complete association between amhy-homologue with maleness was found in O. argentinensis, O. incisa, O. mauleanum, O. perugiae, O. piquava, O. regia, and O. smitti, whereas O. humensis, O. mirinensis, and O. nigricans showed varied degrees of phenotypic/genotypic sex mismatch. The conservation of amhy gene in Odontesthes provide an interesting framework to study the evolution and the ecological interactions of genotypic and environmental sex determination in this group.Fil: Hattori, Ricardo Shohei. Sao Paulo Fisheries Institue. Unidade de Pesquisa e Desenvolvimento de Campos do Jordão; BrasilFil: Somoza, Gustavo Manuel. Universidad Nacional de San Martin. Instituto Tecnológico de Chascomús - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Tecnológico de Chascomús; ArgentinaFil: Fernandino, Juan Ignacio. Universidad Nacional de San Martin. Instituto Tecnológico de Chascomús - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Tecnológico de Chascomús; ArgentinaFil: Colautti, Dario César. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; ArgentinaFil: Miyoshi, Kaho. Tokyo University of Marine Science and Technology; JapónFil: Gong, Zhuang. Zhejiang Ocean University; ChinaFil: Yamamoto, Yoji. Tokyo University of Marine Science and Technology; JapónFil: Strüssmann, Carlos A.. Tokyo University of Marine Science and Technology; Japó

Resolution of the curse of dimensionality in single-cell RNA sequencing data analysis

1細胞データ解析の精度が飛躍的に向上する前処理法の開発. 京都大学プレスリリース. 2022-08-09.Clearing the mist hiding the genome. 京都大学プレスリリース. 2022-08-09.Single-cell RNA sequencing (scRNA-seq) can determine gene expression in numerous individual cells simultaneously, promoting progress in the biomedical sciences. However, scRNA-seq data are high-dimensional with substantial technical noise, including dropouts. During analysis of scRNA-seq data, such noise engenders a statistical problem known as the curse of dimensionality (COD). Based on high-dimensional statistics, we herein formulate a noise reduction method, RECODE (resolution of the curse of dimensionality), for high-dimensional data with random sampling noise. We show that RECODE consistently resolves COD in relevant scRNA-seq data with unique molecular identifiers. RECODE does not involve dimension reduction and recovers expression values for all genes, including lowly expressed genes, realizing precise delineation of cell fate transitions and identification of rare cells with all gene information. Compared with representative imputation methods, RECODE employs different principles and exhibits superior overall performance in cell-clustering, expression value recovery, and single-cell–level analysis. The RECODE algorithm is parameter-free, data-driven, deterministic, and high-speed, and its applicability can be predicted based on the variance normalization performance. We propose RECODE as a powerful strategy for preprocessing noisy high-dimensional data

A Diagnostic Algorithm for Eosinophilic Granulomatosis with Polyangiitis Initially Diagnosed as Lumbar Disc Hernia or Lumbar Spinal Stenosis: Personal Experience and Review of the Literature

Eosinophilic granulomatosis with polyangiitis (EGPA, Churg-Strauss syndrome) is a rare systemic vasculitis and is difficult to diagnose. EGPA has a number of symptoms including peripheral dysesthesia caused by mononeuropathy multiplex, which is similar to radiculopathy due to lumbar disc hernia or lumbar spinal stenosis. Therefore, EGPA patients with mononeuropathy multiplex often visit orthopedic clinics, but orthopedic doctors and spine neurosurgeons have limited experience in diagnosing EGPA because of its rarity. We report a consecutive series of patients who were initially diagnosed as having lumbar disc hernia or lumbar spinal stenosis by at least 2 medical institutions from March 2006 to April 2013 but whose final diagnosis was EGPA. All patients had past histories of asthma or eosinophilic pneumonia, and four out of five had peripheral edema. Laboratory data showed abnormally increased eosinophil counts, and nerve conduction studies of all patients revealed axonal damage patterns. All patients recovered from paralysis to a functional level after high-dose steroid treatment. We shortened the duration of diagnosis from 49 days to one day by adopting a diagnostic algorithm after experiencing the first case

Prognostic Impact of Pre- and Post-operative P-CRP Levels in Pancreatic Cancer Patients

Background: C-reactive protein (CRP) levels reflect ongoing inflammation and/or tissue damage, and studies suggest that platelets play a role in tumor invasion and metastasis. P-CRP is defined as the multiplied product of serum CRP and platelet levels. Here the prognostic value of pre- and post-operative P-CRP levels in pancreatic cancer (PC) patients was assessed. Methods: This retrospective study used data from 107 consecutive PC patients who had undergone either pancreaticoduodenectomy or distal pancreatectomy. Clinicopathological parameters and pre/post-operative laboratory data derived from patient records were used for analyses. P-CRP was defined as the product of peripheral thrombocyte count (/uL) × serum CRP level (mg/dL) divided by 104; the optimal P-CRP cut-off value was defined using receiver operating characteristic curves. Results: PC patients were classified as either P-CRPLow (< 1.782; n = 49) or P-CRPHigh (≥ 1.782; n = 58), based on the cut-off value of 1.782. Univariate analysis revealed that performance status, clinical stage, pathological T and N stages, P-CRP, and carbohydrate antigen 19-9 (CA19-9) significantly affected overall survival (OS). Multivariate analysis revealed that independent risk factors for OS were pathological N stage, P-CRP, and CA19-9. Additionally, 103 PC patients for whom postoperative data were available were classified into four groups (P-CRPLow-Down, P-CRPLow-Up, P-CRPHigh-Down and P-CRPHigh-Up), based on preoperative P-CRP and postoperative trend of P-CRP, and we found that prognosis, in terms of OS, was significantly different among these groups (P = 0.012). Conclusion: Pre- and post-operative P-CRP values are a potential predictor of prognosis in PC patients