• Computers and Concrete
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• 제27권4호
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• pp.333-341
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• 2021

Steel slag, an industrial reject from the steel rolling process, has been identified as one of the suitable, environmentally friendly materials for concrete production. Given that the coarse aggregate portion represents about 70% of concrete constituents, other economic approaches have been found in the use of alternative materials such as steel slag in concrete. Unfortunately, a standard framework for its application is still lacking. Therefore, this study proposed functional model equations for the determination of strength properties (compression and splitting tensile) of steel slag aggregate concrete (SSAC), using gene expression programming (GEP). The study, in the experimental phase, utilized steel slag as a partial replacement of crushed rock, in steps 20%, 40%, 60%, 80%, and 100%, respectively. The predictor variables included in the analysis were cement, sand, granite, steel slag, water/cement ratio, and curing regime (age). For the model development, 60-75% of the dataset was used as the training set, while the remaining data was used for testing the model. Empirical results illustrate that steel aggregate could be used up to 100% replacement of conventional aggregate, while also yielding comparable results as the latter. The GEP-based functional relations were tested statistically. The minimum absolute percentage error (MAPE), and root mean square error (RMSE) for compressive strength are 6.9 and 1.4, and 12.52 and 0.91 for the train and test datasets, respectively. With the consistency of both the training and testing datasets, the model has shown a strong capacity to predict the strength properties of SSAC. The results showed that the proposed model equations are reliably suitable for estimating SSAC strength properties. The GEP-based formula is relatively simple and useful for pre-design applications.

• Steel and Composite Structures
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• 제44권3호
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• pp.309-324
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• 2022

The post-fire elastic stiffness and performance of concrete-filled steel tube (CFST) columns containing recycled aggregate concrete (RAC) has rarely been addressed, particularly in terms of material properties. This study was conducted with the aim of assessing the modulus of elasticity of recycled aggregate concrete-filled steel tube (RACFST) stub columns following thermal loading. The test data were employed to model and assess the elastic modulus of circular RACFST stub columns subjected to axial loading after exposure to elevated temperatures. The length/diameter ratio of the specimens was less than three to prevent the sensitivity of overall buckling for the stub columns. The gene expression programming (GEP) method was employed for the model development. The GEP model was derived based on a comprehensive experimental database of heated and non-heated RACFST stub columns that have been properly gathered from the open literature. In this study, by using specifications of 149 specimens, the variables were the steel section ratio, applied temperature, yielding strength of steel, compressive strength of plain concrete, and elastic modulus of steel tube and concrete core (RAC). Moreover, parametric and sensitivity analyses were also performed to determine the contribution of different effective parameters to the post-fire elastic modulus. Additionally, comparisons and verification of the effectiveness of the proposed model were made between the values obtained from the GEP model and the formulas proposed by different researchers. Through the analyses and comparisons of the developed model against formulas available in the literature, the acceptable accuracy of the model for predicting the post-fire modulus of elasticity of circular RACFST stub columns was seen.

• Computers and Concrete
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• 제31권2호
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• pp.111-121
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• 2023

The influence of material composition such as aggregate types, addition of supplementary cementitious materials as well as exposed temperature levels have significant impacts on concrete residual mechanical strength properties when exposed to elevated temperature. This study is based on data obtained from literature for fly ash blended concrete produced with natural and recycled concrete aggregates to efficiently develop prediction models for estimating its residual compressive strength after exposure to high temperatures. To achieve this, an extensive database that contains different mix proportions of fly ash blended concrete was gathered from published articles. The specific design variables considered were percentage replacement level of Recycled Concrete Aggregate (RCA) in the mix, fly ash content (FA), Water to Binder Ratio (W/B), and exposed Temperature level. Thereafter, a simplified mathematical equation for the prediction of concrete's residual compressive strength using Gene Expression Programming (GEP) was developed. The relative importance of each variable on the model outputs was also determined through global sensitivity analysis. The GEP model performance was validated using different statistical fitness formulas including R², MSE, RMSE, RAE, and MAE in which high R² values above 0.9 are obtained in both the training and validation phase. The low measured errors (e.g., mean square error and mean absolute error are in the range of 0.0160 - 0.0327 and 0.0912 - 0.1281 MPa, respectively) in the developed model also indicate high efficiency and accuracy of the model in predicting the residual compressive strength of fly ash blended concrete exposed to elevated temperatures.

• Childhood Kidney Diseases
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• 제8권2호
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• pp.138-148
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• 2004

Purpose: Regardless of the underlying diseases, the proteinuric condition demonstrates ultrastructural changes in podocytes with retraction and effacement of the highly specialized interdigitating foot processes. We examined the molecular basis for this alteration of the podocyte phenotypes, including quantitative and distributional changes of ZO-1 protein as a candidate contributing to the pathogenic changes in the barrier to protein filtration. Methods: To investigate whether high glucose and advanced glycosylation endproduct(AGE) induce podocyte cytoskeletal changes, we cultured rat GEpC under 1) normal glucose(5 mM=control) or 2) high glucose(30 mM) or 3) AGE-added or 4) high glucose plus AGE-added conditions. The distribution of ZO-1 was observed by confocal microscope and the change of ZO-1 expression was measured by Western blotting and RT-PCR. Results: By confocal microscopy, we observed that ZO-1 moves from peripheral cytoplasm to inner actin filaments complexes in both AGE-added and high glucose condition. In Western blotting, high glucose or AGE-added condition decreased the ZO-1 protein expression by 11.1%(P>0.05) and 2.3%(P>0.05), respectively compared to the normal glucose condition. High glucose plus AGE-added condition further decreased ZO-1 protein expression to statistically significant level(12%, P<0.05). No significant change was seen in the osmotic control. In RT-PCR, high glucose plus AGE-added condition significantly decreased the expression of ZO-1 mRNA by 12% compared to normal glucose condition. Conclusion: We suggest that both high glucose and AGE-added condition induce the cytoplasmic translocation and suppresses the production of ZO-1 at transcriptional level and these changes may explain the functional changes of podocytes in diabetic conditions.

• Radiation Oncology Journal
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• 제24권1호
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• pp.58-66
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• 2006

Purpose: Renal irradiation can lead to the development of radiation nephropathy, and this is characterized by the accumulation of extracellular matrix and final fibrosis. To determine the possible role of the glomerular epithelial cell, the radiation-induced changes in the expression of its genes associated with the extracellular matrix were analyzed. Materials and Methods: Rat glomerular epithelial cells (GEpC) were irradiated with a single dose of 0, 2, 5, 10 and 20 Gy with using 6 MV LINAC (Siemens, USA), and the samples were collected 6, 24, 48 and 72 hours post-irradiation, respectively. Northern blotting, western blotting and zymography were used to measure the expression level of fibronectin (Fn), plasminogen activator inhibitor-1 (Pai-1), matrix metalloproteinases-2, 9 (MMP-2, 9), tissue inhibitor of metalloproteinase-2 (TIMP-2), tissue-type plasminogen activator (t-PA) and urokinase-type plasminogen activator (u-PA). Results: Irradiation with a single dose of 10 Gy resulted in a significant increase in Fn mRNA since 24 hours post-irradiation, and a single dose of 5 and 10 Gy significantly increased the Fn immunoreactive protein measured 48 hours post-irradiation. An increase in Pai-1 mRNA and protein was also observed and especially, a single dose of 10 Gy significantly increased the mRNA measured 24 and 48 hours post-irradiation. The active MMP-2 measured 24 hours post-irradiation slightly increased in a dose dependent manner, but this increase did not reach statistical significance. The levels of MMP-9, TIMP-2, t-PA and u-PA appeared unaltered after irradiation. Conclusion: Irradiation of the glomerular epithelial cells altered the expression of genes associated with the extracellular matrix, implying that the glomerular epithelial cell may be involved in the development of radiation nephropathy.

• ALGAE
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• 제30권2호
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• pp.121-137
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• 2015

Studies on carbon flux in the oceans have been highlighted in recent years due to increasing awareness about climate change, but the coastal ecosystem remains one of the unexplored fields in this regard. In this study, the dynamics of carbon flux in a vegetative coastal ecosystem were examined by an evaluation of net and gross ecosystem production (NEP and GEP) and $CO_2$ exchange rates (net ecosystem exchange, NEE). To estimate NEP and GEP, community production and respiration were measured along different habitat types (eelgrass and macroalgal beds, shallow and deep sedimentary, and deep rocky shore) at Gwangyang Bay, Korea from 20 June to 20 July 2007. Vegetative areas showed significantly higher ecosystem production than the other habitat types. Specifically, eelgrass beds had the highest daily GEP ($6.97{\pm}0.02g\;C\;m^{-2}\;d^{-1}$), with a large amount of biomass and high productivity of eelgrass, whereas the outer macroalgal vegetation had the lowest GEP ($0.97{\pm}0.04g\;C\;m^{-2}\;d^{-1}$). In addition, macroalgal vegetation showed the highest daily NEP ($3.31{\pm}0.45g\;C\;m^{-2}\;d^{-1}$) due to its highest P : R ratio (2.33). Furthermore, the eelgrass beds acted as a $CO_2$ sink through the air-seawater interface according to NEE data, with a carbon sink rate of $0.63mg\;C\;m^{-2}\;d^{-1}$. Overall, ecosystem production was found to be extremely high in the vegetated systems (eelgrass and macroalgal beds), which occupy a relatively small area compared to the unvegetated systems according to our conceptual diagram of a carbon-flux box model. These results indicate that the vegetative ecosystems showed significantly high capturing efficiency of inorganic carbon through coastal primary production.

• Childhood Kidney Diseases
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• 제17권2호
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• pp.79-85
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• 2013

Purpose: To test whether the expression of P-cadherin, a component of slit diaphragms between podocyte foot processes, would be altered by puromycin aminonucleoside (PAN) in a cultured podocyte in vitro. Methods: Rat glomerular epithelial cells (GEpC) were cultured with various concentrations of PAN. The distribution of P-cadherin was examined with a confocal microscope. Western blotting and reverse transcriptase-polymerase chain reaction (RT-PCR) were used to measure the change in P-cadherin expression. Results: This study found that P-cadherin was concentrated in the inner and peripheral cytoplasm with high concentrations of PAN under immunofluorescence views. Western blotting of GEpC revealed that PAN induced a decrease of P-cadherin in dose- and time-dependent manners. A high dose ($50{\mu}g/mL$) of PAN decreased P-cadherin expression by 21.9% at 24 h (P <0.05) and 31.9% at 48 h (P <0.01) compared to those without PAN. In RT-PCR, high concentrations ($50{\mu}g/mL$) of PAN also decreased P-cadherin mRNA expression, similar to protein suppression, by 23.5% at 48 h (P <0.05). Conclusion: Podocytes exposed to PAN in vitro concentrated P-cadherin internally, and reduced P-cadherin mRNA and protein expression. This could explain the development of proteinuria in experimental PAN-induced nephropathy.

• Earthquakes and Structures
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• 제15권4호
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• pp.403-410
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• 2018

The choice of attenuation relationships is one of the most important parts of seismic hazard analysis as using a different attenuation relationship will cause significant differences in the final result, particularly in near distances. This problem is responsible for huge sensibilities of attenuation relationships which are used in seismic hazard analysis. For achieving this goal, attenuation relationships require a good compatibility with the target region. Many researchers have put substantial efforts in their studies of strong ground motion predictions, and each of them had an influence on the progress of attenuation relationships. In this study, two attenuation relationships are presented using seismic data of Mazandaran province in the north of Iran by Genetic Expression Programming (GEP) algorithm. Two site classifications of soil and rock were considered regarding the shear wave velocity of top 30 meters of site. The quantity of primary data was 93 records; 63 of them were recorded on rock and 30 of them recorded on soil. Due to the shortage of records, a regression technique had been used for increasing them. Through using this technique, 693 data had been created; 178 data for soil and 515 data for rock conditions. The Results of this study show the observed PGA values in the region have high correlation coefficients with the predicted values and can be used in seismic hazard analysis studies in the region.

• Clinical and Experimental Pediatrics
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• 제55권10호
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• pp.371-376
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• 2012

Purpose: Puromycin aminonucleoside (PAN) specifically injures podocytes, leading to foot process effacement, actin cytoskeleton disorganization, and abnormal distribution of slit diaphragm proteins. p130Cas is a docking protein connecting F-actin fibers to the glomerular basement membrane (GBM) and adapter proteins in glomerular epithelial cells (GEpCs; podocytes). We investigated the changes in the p130Cas expression level in the PAN-induced pathological changes of podocytes in vitro. Methods: We observed changes in the p130Cas expression in cultured rat GEpCs and mouse podocytes treated with various concentrations of PAN and antioxidants, including probucol, epigallocatechin gallate (EGCG), and vitamin C. The changes in the p130Cas expression level were analyzed using confocal immunofluorescence imaging, Western blotting, and polymerase chain reaction. Results: In the immunofluorescence study, p130Cas showed a diffuse cytoplasmic distribution with accumulation at distinct sites visible as short stripes and colocalized with P-cadherin. The fluorescences of the p130Cas protein were internalized and became granular by PAN administration in a dose-dependent manner, which had been restored by antioxidants, EGCG and vitamin C. PAN also decreased the protein and mRNA expression levels of p130Cas at high doses and in a longer exposed duration, which had been also reversed by antioxidants. Conclusion: These findings suggest that PAN modulates the quantitative and distributional changes of podocyte p130Cas through oxidative stress resulting in podocyte dysfunction.

• Geomechanics and Engineering
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• 제30권6호
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• pp.551-564
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• 2022

Fragmenting the rock mass is considered as the most important work in open-pit mines. Ground vibration is the most hazardous issue of blasting which can cause critical damage to the surrounding structures. This paper focuses on developing an explicit model to predict the ground vibration through an multi objective evolutionary polynomial regression (MOGA-EPR). To this end, a database including 79 sets of data related to a quarry site in Malaysia were used. In addition, a gene expression programming (GEP) model and several empirical equations were employed to predict ground vibration, and their performances were then compared with the MOGA-EPR model using the mean absolute error (MAE), root mean square error (RMSE), mean (𝜇), standard deviation of the mean (𝜎), coefficient of determination (R²) and a20-index. Comparing the results, it was found that the MOGA-EPR model predicted the ground vibration more precisely than the GEP model and the empirical equations, where the MOGA-EPR scored lower MAE and RMSE, 𝜇 and 𝜎 closer to the optimum value, and higher R² and a20-index. Accordingly, the proposed MOGA-EPR model can be introduced as a useful method to predict ground vibration and has the capacity to be generalized to predict other blasting effects.