Optimal Design of a Centrifugal Compressor Impeller Using Evolutionary Algorithms

An optimization study was conducted on a centrifugal compressor. Eight design variables were chosen from the control points for the Bezier curves which widely influenced the geometric variation; four design variables were selected to optimize the flow passage between the hub and the shroud, and other four design variables were used to improve the performance of the impeller blade. As an optimization algorithm, an artificial neural network (ANN) was adopted. Initially, the design of experiments was applied to set up the initial data space of the ANN, which was improved during the optimization process using a genetic algorithm. If a result of the ANN reached a higher level, that result was re-calculated by computational fluid dynamics (CFD) and was applied to develop a new ANN. The prediction difference between the ANN and CFD was consequently less than 1% after the 6th generation. Using this optimization technique, the computational time for the optimization was greatly reduced and the accuracy of the optimization algorithm was increased. The efficiency was improved by 1.4% without losing the pressure ratio, and Pareto-optimal solutions of the efficiency versus the pressure ratio were obtained through the 21st generation

Evaluation for Damaged Degree of Vegetation by Forest Fire Using LiDAR and Digital Aerial Photograph

The amount of vegetation physically damaged by forest fire can be evaluated using lidar (Light Detection And Ranging) data because the loss of canopy height and width by forest fire can be relevant to the number of points transmitted to the ground through the canopy of the damaged forest. On the other hand, the biological damage of vegetation caused by forest fire can be obtained from the Normalized Difference Vegetation Index (NDVI), which determines the vegetation vitality. In this study, the degree of physical damage from the lidar data was classified into serious physical damage (SPD) and light physical damage (LPD). The degree of biological damage using NDVI was likewise classified into serious biological damage (SBD) and light biological damage (LBD). Finally, the damaged area was graded into four categories: (a) SPD and SBD, (b) LPD and SBD, (c) SPD and LBD, and (d) LPD and LBD. The accuracy assessment for the area classified into four grades showed an overall accuracy of 0.74, and a kappa value of 0.61 which provides improvement over previous works

Imaging Findings of Central Nervous System Vasculitis Associated with Goodpasture's Syndrome: a Case Report

Glomerulonephritis and pulmonary hemorrhage are features of Goodpasture's syndrome. Goodpasture's syndrome accompanied with central nervous system (CNS) vasculitis is extremely rare. Herein, we report a rare case of CNS vasculitis associated with Goodpasture's syndrome in a 34-year-old man, who presented with a seizure and sudden onset of right sided weakness. He also had recurrent hemoptysis of one month's duration. Goodpasture's syndrome is histologically diagnosed by intense linear deposits of IgG along the glomerular basement membrane in both renal and lung tissues

Increased urinary Angiotensinogen/Creatinine (AGT/Cr) ratio may be associated with reduced renal function in autosomal dominant polycystic kidney disease patients

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited.Background Autosomal dominant polycystic kidney disease (ADPKD) is one of the most common hereditary kidney diseases that frequently result in renal failure. In this cross-sectional observational cohort study, we evaluated urinary angiotensinogen (AGT) as a potential biomarker to assess renal function in ADPKD. Methods Urinary AGT was measured in 233 ADPKD patients and its association with estimated glomerular filtration rate (eGFR) and height-adjusted total kidney volume (htTKV) were evaluated. The localization of AGT and other renin-angiotensin system (RAS)-related molecules were identified using immunohistochemistry in human ADPKD tissues. Results Baseline urinary AGT/Cr was negatively correlated with CKD-EPI eGFR (r 2= 0.162, P < 0.001) and positively correlated with htTKV (r2 = 0.107, P < 0.001). Both urinary AGT/Cr and plasma renin activity levels were significantly elevated in hypertensive ADPKD patients. Among hypertensive subjects, urinary AGT/Cr was significantly increased in the advanced CKD stages (III-V) compared to early CKD stages (I-II) (28.6 ± 60.3 vs. 93.2 ± 139.3 μg/g, P < 0.001). Immunohistochemical study showed strong expression of AGT along the cyst-lining epithelial cells as well as the nearby compressed tubular epithelial cells. Conclusions Our results suggested that urinary AGT/Cr may be a valuable biomarker for renal damage in ADPKD since intrarenal ischemic insults induced by cyst growth and subsequent intrarenal RAS activation may play a potential role in the development of hypertension and renal dysfunction in ADPKD

Transcatheter Arterial Embolization Therapy for a Massive Polycystic Liver in Autosomal Dominant Polycystic Kidney Disease Patients

Polycystic liver is the most common extra-renal manifestation associated with autosomal dominant polycystic kidney disease (ADPKD), comprising up to 80% of all features. Patients with polycystic liver often suffer from abdominal discomfort, dyspepsia, or dyspnea; however, there have been few ways to relieve their symptoms effectively and safely. Therefore, we tried transcatheter arterial embolization (TAE), which has been used in treating hepatocellular carcinoma. We enrolled four patients with ADPKD in Seoul National University Hospital, suffering from enlarged polycystic liver. We embolized the hepatic arteries supplying the dominant hepatic segments replaced by cysts using polyvinyl alcohol particles and micro-coils. The patients were evaluated 12 months after embolization for the change in both liver and cyst volumes. Among four patients, one patient was lost in follow up and 3 patients were included in the analysis. Both liver (33%; 10%) and cyst volume (47.7%; 11.4%) substantially decreased in two patients. Common adverse events were fever, epigastric pain, nausea, and vomiting. We suggest that TAE is effective and safe in treating symptomatic polycystic liver in selected ADPKD patients

Do we need colonoscopy verification in patients with fundic gland polyp?

Background/AimsThe aim of this study was to evaluate the prevalence of colorectal neoplasia in subjects with fundic gland polyps (FGPs) and the relationship between FGPs and colorectal neoplasia in Korea.MethodsWe analyzed 128 consecutive patients with FPGs who underwent colonoscopy between January 2009 and December 2013. For each case, age- (±5 years) and sex-matched controls were identified from among patients with hyperplastic polyps, gastric neoplasms, and healthy controls. Clinical characteristics were reviewed from medical records, colonoscopic findings, pathologic findings, and computed tomography images. The outcome was evaluated by comparison of advanced colonic neoplasia detection rates.ResultsOf the 128 patients, seven (5.1%) had colon cancers and seven (5.1%) had advanced adenomas. A case-control study revealed that the odds of detecting a colorectal cancer was 3.8 times greater in patients with FGPs than in the age- and sex-matched healthy controls (odds ratio [OR], 3.80; 95% confidence interval [CI], 1.09–13.24; P =0.04) and 4.1 times greater in patients with FGPs than in healthy controls over 50 years of age (OR, 4.10; 95% CI, 1.16–14.45; P =0.04). Among patients with FGPs over 50 years old, male sex (OR, 4.83; 95% CI, 1.23–18.94; P =0.02), and age (OR, 9.90; 95% CI, 1.21–81.08; P =0.03) were associated with an increased prevalence of advanced colorectal neoplasms.ConclusionsThe yield of colonoscopy in colorectal cancer patients with FGPs was substantially higher than that in average-risk subjects. Colonoscopy verification is warranted in patients with FGPs, especially in those 50 years of age or older

CD70–CD27 ligation between neural stem cells and CD4+ T cells induces Fas–FasL-mediated T-cell death

1. Introduction : Neural stem cells (NSCs) are among the most promising candidates for cell replacement therapy in neuronal injury and neurodegenerative diseases. One of the remaining obstacles for NSC therapy is to overcome the alloimmune response on NSCs by the host. 2. Methods : To investigate the mechanisms of immune modulatory function derived from the interaction of human NSCs with allogeneic T cells, we examined the immune regulatory effects of human NSCs on allogeneic T cells in vitro. 3. Results : Significantly, NSCs induced apoptosis of allogeneic T cells, in particular CD4+ T cells. Interaction of CD70 on NSCs and CD27 on CD4+ T cells mediated apoptosis of T cells. Thus, blocking CD70–CD27 interaction prevented NSC-mediated death of CD4+ T cells. 4. Conclusions : We present a rational explanation of NSC-induced immune escape in two consecutive stages. First, CD70 constitutively expressed on NSCs engaged CD27 on CD4+ T cells, which induced Fas ligand expression on CD4+ T cells. Second, CD4+ T-cell apoptosis was followed by Fas–Fas ligand interaction in the CD4+ T cells.This work was supported by the Ministry of the Knowledge Economy (grants 2009-67-10033838) and a grant from Hanwha Chemical Corporation (Project No. 0411–20070011).Peer Reviewe