Position and Thickness Optimization of Ribs for Ventilation Covering Using the Micro Genetic Algorithm with an Interpolated Smooth Objective Function

Structures with supporting ribs are adopted in many fields of engineering. These ribs are attached to the main plate or shell to increase stiffness and reduce the stresses of a structure. Currently, much research in structural optimization has been devoted to size or thickness optimizations. In this study, the discrete positions of the ribs of a structure are optimized in addition to their thicknesses. The objective function, which is the total weight of a structure, is a continuous function with respect to the thickness of the ribs. However, it is a stepwise function of a dimensionless variable, which represents the set of positions of the ribs. Because of this stepwise objective function, the gradient method of optimization is not applicable. Therefore, we applied the micro genetic algorithm (MGA), which does not need derivatives of the objective function. To accelerate the rate of convergence, the stepwise objective function is interpolated to a smooth artificial objective function that does not alter the optimal solution

Structural safety inspection of reinforced concrete structures considering failure probabilities of structural members

Regular safety inspections of existing reinforced concrete (RC) structures are required according to the regulations and criteria set by each country. In South Korea, the safety inspection regulations provided by the Korea Infrastructure Safety and Technology Corporation (KISTEC) are followed. These regulations were developed based on fuzzy theory to avoid subjective decisions, and provide standardized deterioration grades for member types, floors, and the entire structure. However, the safety inspection regulation by the KISTEC often provides unconservative evaluation results. In particular, as the importance factors of beam and slab members are set lower than those of other members, there are cases in which deteriorations occurring in beams and slabs are not properly reflected in the floor level evaluation. In this study, to overcome such limitations, case studies were carried out and modified importance factors for structural member types were proposed considering the failure probabilities of each member type based on the reliability theory. The importance modification factor was calculated based on the strength ratio of structural members so that the more dangerous the members are, the more impact they give on the evaluation. Overall, compared to the KISTEC method, the proposed method provided conservative but practical assessment results, and it was found that the proposed importance factors can be very useful to properly reflect the effects of damaged members on the deterioration status evaluation of the floors and the entire structure

17-Oxo-docosahexaenoic acid induces Nrf2-mediated expression of heme oxygenase-1 in mouse skin in vivo and in cultured murine epidermal cells

Recently, growing attention has been given to new classes of bioactive lipid mediators derived from omega-3 polyunsaturated fatty acids, such as docosahexaenoic acid (DHA), especially in the context of their role as endogenous signal modulators. One such molecule is 17-oxo-DHA, generated from DHA by the action of COX2 and a dehydrogenase. The redox-sensitive transcription factor, Nrf2 plays a key role in cellular stress responses. In the present study, the effects of 17-oxo-DHA on Nrf2-mediated expression of cytoprotective enzymes were examined in mouse skin in vivo and cultured murine epidermal JB6 cells. Topical application of 17-oxo-DHA markedly elevated the nuclear localization of Nrf2 and expression of heme oxygenase-1 (HO-1) and NAD(P) H:quinone oxidoreductase-1 in hairless mouse skin. In contrast to 17-oxo-DHA, the non-electrophilic metabolic precursor 17-hydroxy-DHA was a much weaker inducer of Nrf2 activation and its target protein expression. Likewise, 17-oxo-DHA significantly enhanced nuclear translocation and transcriptional activity of Nrf2 with concomitant upregulation of HO-1 expression in cultured JB6 cells. 17-Oxo-DHA was a much stronger inducer of Nrf2-mediated antioxidant response than its parent molecule, DHA. HO-1 expression was abolished in Nrf2 knockdown JB6 cells or embryo fibroblasts from Nrf2 knock out mice. 17-Oxo-DHA also markedly reduced the level of Keap1 protein by inducing ubiquitination. Mutation of Cys151 and Cys273 in Keap1 abrogated 17-oxo-DHA-induced ubiquitination and proteasome-mediated degradation of Keap1 as well as HO-1 expression, suggesting that these cysteine residues are putative sites for 17-oxo-DHA binding. Further, Keap1 degradation stimulated by 17-oxo-DHA coincided with accumulation of the autophagy substrate, p62/SQSTM1.

Distributional Characteristics of Plants in Hajo Island of Jeollanam-do, South Korea

AbstractThis study investigated the plant distribution in Hajo Island, Jodo-myeon, Jindo-gun, Jeollanam-do, South Korea. The surveyed plants were recorded as total 483 taxa, 100 families, 298 genera, 427 species, 1 subspecies, 52 varieties, and 3 forms. Total 1,360 pieces were obtained as evidential specimen. Through floristic survey and collection in Hajo Island, Jodo-myeon, Jindo-gun, Jeollanam-do, 1,360 items of specimen were obtained. Based on the specimen, the flora in Hajo Island included total 483 taxa, 100 families, 298 genera, 427 species, 1 subspecies, 52 varieties, and 3 forms. The investigation was carried out based on mountains (Mt. Dondae-bong, Mt. Songarak, and Mt. Singeum), reservoirs (Jodo reservoir, Yukdong reservoir), Hajodo lighthouse, and Jodo bridge. In particular, rare plants designated by Korea Forest Service were recorded as 12 taxa such as Glochidion chodoense, Crypsinus hastatus, Celtis choseniana, Ardisia crenata, Millettia japonica, etc. Endemic plants were recorded as 3 taxa such as Hepatica insularis, etc. Special plants over 3rd degree designated by the Ministry of Environment were recorded as 31 taxa such as Litsea japonica, Kadsura japonica, Raphiolepis indica var. umbellata, Verbena officinalis, Stauntonia hexaphylla, etc. Naturalized plants were recorded as 31 taxa, accounting for 6.4% of the total, such as Physalis angulata, Aster subulatus, Euphorbia supina, Chenopodium ambrosioides, Bromus unioloides, etc

Clinical Study Effect of Omega-3 Fatty Acid on the Fatty Acid Content of the Erythrocyte Membrane and Proteinuria in Patients with Diabetic Nephropathy

Diabetic nephropathy is the leading cause of end-stage renal disease and is associated with an increased risk of cardiovascular events. Dietary omega-3 fatty acid (FA) has cardioprotective effect and is associated with a slower deterioration of albumin excretion in patients with diabetic nephropathy. In this study, we evaluated the effect of omega-3 FA on proteinuria in diabetic nephropathy patients who are controlling blood pressure (BP) with angiotensin converting enzyme inhibitor (ACEi) or angiotensin II receptor blocker (ARB). In addition, we identified changes in erythrocyte membrane FA contents. A total of 19 patients who were treated with ACEi or ARB for at least 6 months were treated for 12 weeks with omega-3 FA (Omacor, 3 g/day) or a control treatment (olive oil, 3 g/day). Proteinuria levels were unchanged after 12 weeks compared with baseline values in both groups. The erythrocyte membrane contents of omega-3 FA and eicosapentaenoic acid (EPA) were significantly increased, and oleic acid, arachidonic acid : EPA ratio, and omega-6 : omega-3 FA ratio were significantly decreased after 12 weeks compared with the baseline values in the omega-3 FA group. Although omega-3 FA did not appear to alter proteinuria, erythrocyte membrane FA contents, including oleic acid, were altered by omega-3 FA supplementation

Acute Diffuse Phlegmonous Esophagogastritis: A Case Report

Acute phlegmonous infection of the gastrointestinal tract is characterized by purulent inflammation of the submucosa and muscular layer with sparing of the mucosa. The authors report a rare case of acute diffuse phlegmonous esophagogastritis, which was well diagnosed based on the typical chest computed tomographic (CT) findings and was successfully treated. A 48-yr-old man presented with left chest pain and dyspnea for three days. Chest radiograph on admission showed mediastinal widening and bilateral pleural effusion. The patient became febrile and the amount of left pleural effusion is increased on follow-up chest radiograph. Left closed thoracostomy was performed with pus drainage. A CT diagnosis of acute phlegmonous esophagogastritis was suggested and a surgery was decided due to worsening of clinical condition of the patient and radiologic findings. Esophageal myotomies were performed and the submucosal layer was filled with thick, cheesy materials. The patient was successfully discharged with no postoperative complication