Impeller Stall Induced by Reverse Propagation of Non-Uniform Flow

LecturesIn the case of centrifugal compressors, minor non-uniform flow upstream of the impeller is induced by an asymmetrical configuration in the circumferential direction at the compressor suction casing. This non-uniform flow is transmitted to the impeller discharge, but this minor non-uniform flow does not usually cause an adverse effect on the impeller stage performance. However, we found this is amplified at the return channel due to flow separation at reduced flows (depending on return channel geometry), and the amplified non-uniform flow did induce impeller stall by reverse propagation from the return channel to the impeller. These non-uniform flows caused a significant operating range reduction for a large flow coefficient impeller. The aerodynamics issues were mitigated using CFD analysis techniques, and eventually confirmed by the compressor performance during shop performance testing. The OEM conducted the CFD analyses using two (2) return channel geometries with several CFD models to verify the effect of the return channel geometry on impeller stall and to Copyright© 2018 by Turbomachinery Laboratory, Texas A&M Engineering Experiment Station confirm the most suitable CFD modeling method for stall evaluation. Shop performance tests utilizing both return channel geometries were conducted and compared to the CFD analyses. These studies were conducted while collaborating with the end-user. The steady CFD calculation was conducted with frozen rotor interface between full annulus impeller and stator parts. The modeling of diffuser and return channel was varied as follows: (1) 1-pitch model for the return channel with mixing plane at diffuser (2) Full-annulus model for the return channel with a mixing plane at the diffuser (3) Full-annulus model for the return channel without a mixing plane at the diffuser From the above studies and the shop performance testing, it was confirmed that the proposed CFD modeling method could simulate the measurements taken during the shop performance tests and that the CFD modeling met

CSN5/Jab1 controls multiple events in the mammalian cell cycle

AbstractThe COP9 signalosome (CSN) complex is critical for mammalian cell proliferation and survival, but it is not known how the CSN affects the cell cycle. In this study, MEFs lacking CSN5/Jab1 were generated using a CRE-flox system. MEFs ceased to proliferate upon elimination of CSN5/Jab1. Rescue experiments indicated that the JAMM domain of CSN5/Jab1 was essential. CSN5/Jab1-elimination enhanced the neddylation of cullins 1 and 4 and altered the expression of many factors including cyclin E and p53. CSN5/Jab1-elimination inhibited progression of the cell cycle at multiple points, seemed to initiate p53-independent senescence and increased the ploidy of cells. Thus, CSN5/Jab1 controls different events of the cell cycle, preventing senescence and endocycle as well as the proper progression of the somatic cell cycle.Structured summaryMINT-8046253: Csn1 (uniprotkb:Q99LD4) physically interacts (MI:0914) with Csn5 (uniprotkb:O35864), Csn8 (uniprotkb:Q8VBV7), Csn3 (uniprotkb:O88543), Csn7b (uniprotkb:Q8BV13) and Csn6 (uniprotkb:O88545) by anti bait coimmunoprecipitation (MI:0006

Impeller Stall Induced by Reverse Propagation of Non-Uniform Flow

LecturesIn the case of centrifugal compressors, minor non-uniform flow upstream of the impeller is induced by an asymmetrical configuration in the circumferential direction at the compressor suction casing. This non-uniform flow is transmitted to the impeller discharge, but this minor non-uniform flow does not usually cause an adverse effect on the impeller stage performance. However, we found this is amplified at the return channel due to flow separation at reduced flows (depending on return channel geometry), and the amplified non-uniform flow did induce impeller stall by reverse propagation from the return channel to the impeller. These non-uniform flows caused a significant operating range reduction for a large flow coefficient impeller. The aerodynamics issues were mitigated using CFD analysis techniques, and eventually confirmed by the compressor performance during shop performance testing. The OEM conducted the CFD analyses using two (2) return channel geometries with several CFD models to verify the effect of the return channel geometry on impeller stall and to Copyright© 2018 by Turbomachinery Laboratory, Texas A&M Engineering Experiment Station confirm the most suitable CFD modeling method for stall evaluation. Shop performance tests utilizing both return channel geometries were conducted and compared to the CFD analyses. These studies were conducted while collaborating with the end-user. The steady CFD calculation was conducted with frozen rotor interface between full annulus impeller and stator parts. The modeling of diffuser and return channel was varied as follows: (1) 1-pitch model for the return channel with mixing plane at diffuser (2) Full-annulus model for the return channel with a mixing plane at the diffuser (3) Full-annulus model for the return channel without a mixing plane at the diffuser From the above studies and the shop performance testing, it was confirmed that the proposed CFD modeling method could simulate the measurements taken during the shop performance tests and that the CFD modeling met

Serum chemokine levels are associated with the outcome of pegylated interferon and ribavirin therapy in patients with chronic hepatitis C

Aim: Serum chemokine levels and amino acid substitutions in the interferon-sensitivity determining region (ISDR) and core region have been associated with treatment outcome of pegylated interferon and ribavirin therapy in genotype 1 hepatitis C virus (HCV)-infected patients. The present study was conducted to clarify the association between serum chemokines and treatment outcome in patients with chronic HCV-1 infection in a Japanese cohort. Methods: A total of six serum chemokines were quantified before, during and after pegylated interferon and ribavirin treatment in 79 genotype 1 chronic HCV patients using a multiple bead array system. Viral ISDR and core region variants were determined by direct sequencing. Results: The baseline serum levels of eotaxin, IP-10 and RANTES were significantly higher in chronic HCV patients than in controls. High levels of eotaxin and macrophage inflammatory protein (MIP)-1 beta before therapy and more than two mutations in the ISDR were associated with a sustained virological response, and patients with more than two mutations in the ISDR also had significantly higher MIP-1 beta levels. Receiver-operator curve analysis showed a 77% sensitivity and 73% specificity for predicting an SVR using MIP-1 beta values. Conclusion: Serum MIP-1 beta levels may predict the response to HCV treatment with pegylated interferon and ribavirin and are associated with amino acid substitutions in the ISDR.ArticleHEPATOLOGY RESEARCH. 41(6):587-593 (2011)journal articl

Serum interleukin (IL)-10 and IL-12 levels and IL28B gene polymorphisms: pretreatment prediction of treatment failure in chronic hepatitis C

Background: Both IL28B gene polymorphisms and serum levels of interleukin (IL)-10, IL-12p40 and IL-18 have been reported to affect the outcome of natural and pegylated interferon and ribavirin-treated HCV infection. Methods: To clarify their association and predictive value in treatment outcome of genotype 1 HCV-infected patients, we measured pretreatment serum IL-10, IL-12p40 and IL-18 levels using multiplex assays and determined IL28B gene polymorphisms (rs 8099917) in 52 cases with chronic hepatitis C. Results: High baseline levels of IL-10 (P<0.001) and low levels of IL-12p40 (P<0.001) were significantly associated with a non-virological response (NVR) in our cohort. The IL28B polymorphism was tested and TT, TG or GG genotypes were found in 60%, 38% and 2% of patients, respectively, with corresponding NVR rates of 10%, 60% and 100% (P<0.001). Serum cytokine levels were significantly correlated with IL28B gene polymorphisms. When serum IL-10 levels were stratified at 5.0 pg/ml, NVR rates were 50% versus 0% (P=0.004) for the IT genotype and 87% versus 0% (P=0.001) for the TG or GG genotypes. Similarly, low IL-12p40 levels were associated with an NVR in patients with TG or GG genotypes (P=0.006). In multivariate analysis, high IL-10, low IL-12p40 and IL28B TG or GG genotypes were independently associated with an NVR. Conclusions: Serum IL-10 and IL-12p40 levels in combination with IL28B genotype, especially G-allele carriage, are strong predictive markers of an NVR to HCV treatment with pegylated interferon and ribavirin.ArticleANTIVIRAL THERAPY. 16(7):1073-1080 (2011)journal articl

Impeller Stall Induced By Reverse Propagation Of Non-Uniform Flow Generated At Return Channel

LectureIn the case of centrifugal compressors, minor non-uniform flow upstream of the impeller is induced by an asymmetrical configuration in the circumferential direction at the compressor suction casing. This non-uniform flow is transmitted to the impeller discharge, but this minor non-uniform flow does not usually cause an adverse effect on the impeller stage performance. However, we found this is amplified at the return channel due to flow separation at reduced flows (depending on return channel geometry), and the amplified non-uniform flow did induce impeller stall by reverse propagation from the return channel to the impeller. These non-uniform flows caused a significant operating range reduction for a large flow coefficient impeller. The aerodynamics issues were mitigated using CFD analysis techniques, and eventually confirmed by the compressor performance during shop performance testing. The OEM conducted the CFD analyses using two (2) return channel geometries with several CFD models to verify the effect of the return channel geometry on impeller stall and to confirm the most suitable CFD modeling method for stall evaluation. Shop performance tests utilizing both return channel geometries were conducted and compared to the CFD analyses. These studies were conducted while collaborating with the end-user. The steady CFD calculation was conducted with frozen rotor interface between full annulus impeller and stator parts. The modeling of diffuser and return channel was varied as follows: 1) 1-pitch model for the return channel with mixing plane at diffuser 2) Full-annulus model for the return channel with a mixing plane at the diffuser 3) Full-annulus model for the return channel without a mixing plane at the diffuser. From the above studies and the shop performance testing, it was confirmed that the proposed CFD modeling method could simulate the measurements taken during the shop performance tests and that the CFD modeling method utilized was key to properly evaluating stall phenomena

Association of Serum Cytokine Levels With Treatment Response to Pegylated Interferon and Ribavirin Therapy in Genotype 1 Chronic Hepatitis C Patients

Methods. We quantified a total of 8 serum cytokines before, during, and after treatment in 79 genotype 1 chronic HCV patients. Viral ISDR and core region variants were determined by direct sequencing. Results. High levels of interleukin (IL)-12 and IL-18 and more than 2 mutations in the ISDR were associated with a sustained virological response (SVR). Conversely, high baseline IL-10 levels and glutamine at amino acid 70 of the HCV core protein (Gln70) were significantly associated with a nonresponse to treatment, and patients with Gln70 had significantly higher IL-10 levels. In multivariate analysis, low IL-10, high IL-12, and high IL-18 levels were independently associated with an SVR. These 3 cytokine levels were decreased from baseline levels 4 weeks into treatment and remained low in patients with an SVR. Conclusion. Serum IL-10, IL-12, and IL-18 levels are predictive of the response to HCV treatment with pegylated interferon and ribavirin and are associated with amino acid substitutions in the ISDR and core region.ArticleJOURNAL OF INFECTIOUS DISEASES. 203(8):1087-1095 (2011)journal articl

Comparison of carbon dioxide and air insufflation use by non-expert endoscopists during endoscopic retrograde cholangiopancreatography

Background: Endoscopic retrograde cholangiopancreatography (ERCP) is subject to several complications that include a lengthy procedure time, technical difficulty, and active bowel movement induced by air insufflation. In ERCP carried out by non-expert endoscopists who are prone to excessive luminal insufflation, insufflation with carbon dioxide (CO2) may provide better and safer outcomes. We aimed to assess the efficacy and safety of CO2 insufflation during ERCP by non-expert endoscopists. Methods: This study included 208 consecutive patients who received ERCP, excluding those in poor general health or with obstructive lung disease. The first operator for each patient was a non-expert endoscopist having done 50 or fewer ERCP procedures. Primary outcomes were the changes in cardiopulmonary state during ERCP. Secondary outcomes were ERCP complications. We designed a single-center, randomized, prospective, double-blind, controlled trial with CO2 and air insufflation during ERCP. Results: CO2 insufflation did not affect overall procedure progression or results. A positive correlation was observed between procedure time and change in maximal systolic blood pressure from baseline among patients in the air insufflation group, but not in the CO2 insufflation group (correlation coefficient 0.408 vs 0.114, change in the maximal systolic blood pressure from baseline +4.2 vs+1.2mmHg/10min). This was consistent with our findings in patients treated by the first operator alone. The occurrence rate of post-ERCP pancreatitis tended to be lower in the CO2 group than the air group (4/102 [3.9%]vs 0/106 [0%], P=0.056). Conclusions: CO2 insufflation during ERCP by non-expert endoscopists is recommended from the standpoints of efficacy and safety.ArticleDIGESTIVE ENDOSCOPY. 25(2):189-196 (2013)journal articl

Risk factors for pancreatic stone formation in autoimmune pancreatitis over a long-term course

Autoimmune pancreatitis (AIP) has the potential to progress to a chronic state that forms pancreatic stones. The aim of this study was to clarify the risk factors underlying pancreatic stone formation in AIP. Sixty-nine patients with AIP who had been followed for at least 3 years were enrolled for evaluation of clinical and laboratory factors as well as computed tomography and endoscopic retrograde cholangiopancreatography findings. During the course of this study, increased or de novo stone formation was seen in 28 patients, who were defined as the stone-forming group. No stones were observed in 32 patients, who were defined as the non-stone-forming group. Nine patients who had stones at diagnosis but showed no change during the course of this study were excluded from our cohort. Univariate analysis revealed no significant differences in clinical or laboratory factors associated with AIP-specific inflammation between the two groups. However, pancreatic head swelling (P = 0.006) and narrowing of both Wirsung's and Santorini's ducts in the pancreatic head region (P = 0.010) were significantly more frequent in the stone-forming group. Furthermore, multivariate analysis identified Wirsung and Santorini duct narrowing at diagnosis as a significant independent risk factor for pancreatic stone formation (OR 4.4, P = 0.019). A primary risk factor for pancreatic stone formation in AIP was narrowing of both Wirsung's and Santorini's ducts, which most presumably led to pancreatic juice stasis and stone development.ArticleJOURNAL OF GASTROENTEROLOGY. 47(5):553-560 (2012)journal articl

6自由度顎運動測定装置の試用

The purpose of this study was to quantitatively analyze the mandibular movement by the Jaw tracking system with six degree of freedom (MM-JI-E). Displacements of the condyles under maximum clenching with successive loss of mandibular supporting zones were measured. The patient, a 29-year-old man, had been treated at an orthodontic clinic between 1994 and 1997, and temporary full coverage crowns were fabricated on four molars of the lower jaw. He showed no signs of abnormality of stomatognathic function. We measured the jaw movements with MM-JI-E, removing the crowns from the distal end of molars to the mesial. The condylar displacement values were displayed and calculated by the measurement of mandibular movement. When the supporting zones were reduced successively, both condyles moved upwards and slightly forwards (87-117°). The maximal condylar displacement values was 700μm without any support in the molars. We compared the measurements of MM-JI-E with those obtained with another jaw movement tracking system (Bio Pack), with three degree of freedom. The maximum opening paths in sagittal border movement were compared for the two measurement systems. The Bio Pack showed the deflection of the path of anterior maximum opening due to electronic error