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      • KCI등재

        Moringa oleifera biopolymer coagulation and bentonite clay adsorption for hazardous heavy metals removal from aqueous systems

        Udayakumar J,Udayakumar J 한국자원공학회 2020 Geosystem engineering Vol.23 No.5

        Moringa oleifera: seed (MOS) biopolymers and bentonite clay separately have their own heavy metal removal efficiency. However, it is not sufficient for drinking water treatment because of the stringent standards adopted by BIS/WHO. In this study, coagulation with MOS biopolymer and adsorption through bentonite column help in effective removal of heavy metals from the aqueous systems with reduced coagulant dosage at optimum pH conditions. The maximum removal efficiencies of Cd, Cr and Pb are 98.71% at pH 7–8, 99.84% at pH 2–3 and 99.95% at pH 6–7, respectively. The scanning electron microscope, energy-dispersive X-ray spectroscopy and Fouriertransform infrared spectrometer analysis of the sludges of Moringa oleifera and bentonite showed the presence of the metal ions.

      • KCI등재

        Myricetin Protects Against High Glucose-Induced β-Cell Apoptosis by Attenuating Endoplasmic Reticulum Stress via Inactivation of Cyclin-Dependent Kinase 5

        Udayakumar Karunakaran,Suma Elumalai,문준성,전재한,김남두,박근규,원규장,임재찬,이인규 대한당뇨병학회 2019 Diabetes and Metabolism Journal Vol.43 No.2

        Background: Chronic hyperglycemia has deleterious effects on pancreatic β-cell function and turnover. Recent studies support the view that cyclin-dependent kinase 5 (CDK5) plays a role in β-cell failure under hyperglycemic conditions. However, little is known about how CDK5 impair β-cell function. Myricetin, a natural flavonoid, has therapeutic potential for the treatment of type 2 diabetes mellitus. In this study, we examined the effect of myricetin on high glucose (HG)-induced β-cell apoptosis and explored the relationship between myricetin and CDK5. Methods: To address this question, we subjected INS-1 cells and isolated rat islets to HG conditions (30 mM) in the presence or absence of myricetin. Docking studies were conducted to validate the interaction between myricetin and CDK5. Gene expression and protein levels of endoplasmic reticulum (ER) stress markers were measured by real-time reverse transcription polymerase chain reaction and Western blot analysis. Results: Activation of CDK5 in response to HG coupled with the induction of ER stress via the down regulation of sarcoendoplasmic reticulum calcium ATPase 2b (SERCA2b) gene expression and reduced the nuclear accumulation of pancreatic duodenal homeobox 1 (PDX1) leads to β-cell apoptosis. Docking study predicts that myricetin inhibit CDK5 activation by direct binding in the ATP-binding pocket. Myricetin counteracted the decrease in the levels of PDX1 and SERCA2b by HG. Moreover, myricetin attenuated HG-induced apoptosis in INS-1 cells and rat islets and reduce the mitochondrial dysfunction by decreasing reactive oxygen species production and mitochondrial membrane potential (Δψm) loss. Conclusion: Myricetin protects the β-cells against HG-induced apoptosis by inhibiting ER stress, possibly through inactivation of CDK5 and consequent upregulation of PDX1 and SERCA2b.

      • KCI등재

        O-GlcNAc Modification: Friend or Foe in Diabetic Cardiovascular Disease

        Udayakumar Karunakaran,정남호 대한당뇨병학회 2010 Diabetes and Metabolism Journal Vol.34 No.4

        O-Linked b-N-acetyl glucosaminylation (O-GlcNAcylation) is a dynamic post-translational modification that occurs on serine and threonine residues of cytosolic and nuclear proteins in all cell types, including those involved in the cardiovascular system. O-GlcNAcylation is thought to act in a manner analogous to protein phosphorylation. O-GlcNAcylation rapidly cycles on/off proteins in a time scale similar to that for phosphorylation/dephosphorylation of proteins. Several studies indicate that OGlcNAc might induce nuclear localization of some transcription factors and may affect their DNA binding activities. However, at the cellular level, it has been shown that O-GlcNAc levels increase in response to stress and augmentation of this response suppresses cell survival. Increased levels of O-GlcNAc have been implicated as a pathogenic contributor to glucose toxicity and insulin resistance, which are major hallmarks of type 2 diabetes and diabetes-related cardiovascular complications. Thus, O-GlcNAc and its metabolic functions are not yet well-understood; focusing on the role of O-GlcNAc in the cardiovascular system is a viable target for biomedical investigation. In this review, we summarize our current understanding of the role of O-GlcNAc on the regulation of cell function and survival in the cardiovascular system.

      • SCIESCOPUS
      • SCIESCOPUSKCI등재

        Economic evaluation of thorium oxide production from monazite using alkaline fusion method

        Udayakumar, Sanjith,Baharun, Norlia,Rezan, Sheikh Abdul,Ismail, Aznan Fazli,Takip, Khaironie Mohamed Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.7

        Monazite is a phosphate mineral that contains thorium (Th) and rare earth elements. The Th concentration in monazite can be as high as 500 ppm, and it has the potential to be used as fuel in the nuclear power system. Therefore, this study aimed to conduct the techno-economic analysis (TEA) of Th extraction in the form of thorium oxide (ThO<sub>2</sub>) from monazite. Th can be extracted from monazite through an alkaline fusion method. The TEA of ThO<sub>2</sub> production studied parameters, including raw materials, equipment costs, total plant direct and indirect costs, and direct fixed capital cost. These parameters were calculated for the production of 0.5, 1, and 10 ton ThO<sub>2</sub> per batch. The TEA study revealed that the highest production cost was ascribed to installed equipment. Furthermore, the highest return on investment (ROI) of 21.92% was achieved for extraction of 1 ton/batch of ThO<sub>2</sub>, with a payback time of 4.56 years. With further increase in ThO<sub>2</sub> production to 10 ton/batch, the ROI was decreased to 5.37%. This is mainly due to a significant increase in the total capital investment with increasing ThO<sub>2</sub> production scale. The minimum unit production cost was achieved for 1 ton ThO<sub>2</sub>/batch equal to 335.79 $/Kg ThO<sub>2</sub>.

      • KCI등재

        Orthognathic surgery for patients with fibrous dysplasia involved with dentition

        Udayakumar, Santhiya Iswarya Vinothini,Paeng, Jun-Young,Choi, So-Young,Shin, Hong-In,Lee, Sung-Tak,Kwon, Tae-Geon Korean Association of Maxillofacial Plastic and Re 2018 Maxillofacial Plastic Reconstructive Surgery Vol.40 No.-

        Background: Fibrous dysplasia (FD) is characterized by the replacement of normal bone by abnormal fibro-osseous connective tissue and typically treated with surgical contouring of the dysplastic bone. When dysplastic lesions involve occlusion, not only is surgical debulking needed, orthognathic surgery for correction of dentofacial deformity is mandatory. However, the long-term stability of osteotomized, dysplastic bone segments is a major concern because of insufficient screw-to-bone engagement during surgery and the risk of FD lesion re-growth. Case presentation: This case report reviewed two patients with non-syndromic FD that presented with maxillary occlusal canting and facial asymmetry. Le Fort I osteotomy with recontouring of the dysplastic zygomaticomaxillary region had been performed. The stability of osseous segments were favorable. However, dysplastic, newly formed bone covered the previous plate fixation site and mild bony expansion was observed, which did not influence the facial profile. Including the current cases, 15 cases of orthognathic surgery for FD with dentition have been reported in the literature. Conclusion: The results showed that osteotomy did not appear to significantly reduce the long-term stability of the initial fixation insufficiency of the screw to the dysplastic bone. However, based on our results and those of the others, long-term follow-up and monitoring are needed, even in cases where the osteotomized segment shows stable results.

      • KCI등재

        A Systematic Review of Oxidative Stress and Safety of Antioxidants in Diabetes: Focus on Islets and Their Defense

        Udayakumar Karunakaran,박근규 대한당뇨병학회 2013 Diabetes and Metabolism Journal Vol.37 No.2

        A growing body of evidence suggests that hyperglycemia-induced oxidative stress plays an important role in diabetic complications, especially β-cell dysfunction and failure. Under physiological conditions, reactive oxygen species serve as second messengers that facilitate signal transduction and gene expression in pancreatic β-cells. However, under pathological conditions, an imbalance in redox homeostasis leads to aberrant tissue damage and β-cell death due to a lack of antioxidant defense systems. Taking into account the vulnerability of islets to oxidative damage, induction of endogenous antioxidant enzymes or exogenous antioxidant administration has been proposed as a way to protect β-cells against diabetic insults. Here, we consider recent insights into how the redox response becomes deregulated under diabetic conditions, as well as the therapeutic benefits of antioxidants, which may provide clues for developing strategies aimed at the treatment or prevention of diabetes associated with β-cell failure.

      • KCI등재

        IgG4 Levels in Bile for Distinguishing IgG4-Associated Cholangiopathy from Other Biliary Disorders: A Single Blinded Pilot Study

        Udayakumar Navaneethan,Norma G. Gutierrez,Ramprasad Jegadeesan,Preethi GK Venkatesh,Earl Poptic,Madhusudhan R. Sanaka,John J. Vargo,Mansour A. Parsi 대한소화기내시경학회 2014 Clinical Endoscopy Vol.47 No.6

        Background/Aims: Immunoglobulin G4 (IgG4)-associated cholangiopathy (IAC) is an inflammatory disease and may mimic primary sclerosing cholangitis (PSC), cholangiocarcinoma (CCA), or pancreatic cancer on cholangiography. We investigated whether IgG4 levels in bile aspirated during endoscopic retrograde cholangiopancreatography (ERCP) can distinguish IAC from PSC, CCA, and pancreatic cancer. Methods: Bile was aspirated directly from the common bile duct during ERCP in patients with IAC prior to steroid therapy. For control purposes, bile was obtained from patients with PSC, CCA, pancreatic cancer, and benign biliary conditions (sphincter of oddi dysfunction/choledocholithiasis). Results: Biliary IgG4 levels were measured in 54 patients. The median bile IgG4 levels were markedly elevated in patients with IAC (5.5 mg/dL; interquartile range [IQR], 5.1 to 15.6) as compared to patients with benign biliary conditions (0 mg/dL; IQR, 0 to 0.1; p=0.003). The median biliary IgG4 levels in PSC, CCA, and pancreatic cancer were 1.2 (IQR, 0.2 to 3.8), 0.9 (IQR, 0.2 to 3.4), and 0.2 mg/dL (IQR, 0.1 to 0.8), respectively. A cutoff value of 3.8 mg/dL distinguished IAC from PSC and CCA patients with 100% and 76.9% sensitivity and specificity, respectively. Conclusions: The results of this pilot study suggest that measurement of biliary IgG4 levels may have clinical value in distinguishing patients with IAC from biliary disorders that can mimic IAC.

      • KCI등재

        3D simulation of interosseous interference in sagittal split ramus osteotomy for mandibular asymmetry

        Santhiya Iswarya Vinothini Udayakumar,Dohyoung Kim,So-Young Choi,Tae-Geon Kwon 대한악안면성형재건외과학회 2023 Maxillofacial Plastic Reconstructive Surgery Vol.45 No.-

        Background The purpose of this study was to evaluate the pattern of predicted interosseous interference and to determine the influencing factor to volume of bony interference using a computer-assisted simulation system. This retrospective study recruited 116 patients with mandibular prognathism who had undergone sagittal split ramus osteotomy (SSRO) with or without maxillary osteotomy. The patients were divided into 3 groups according to the amount of menton (Me) deviation: less than 2 mm (Group 1), 2–4 mm (Group 2), and more than 4 mm (Group 3). Changes in the distal segments following BSSRO and the volume of the interosseous interference between the proximal and distal segments were simulated after matching preoperative occlusion and postoperative expected occlusion with the cone-beam computed tomography data. Ramal inclinations and other skeletal measurements were analyzed before surgery, immediately after surgery, and at least 6 months after surgery. Results The anticipated interosseous interference was more frequently noted on the contralateral side of chin deviation (long side) than the deviated site (short side) in Groups 2 and 3. More interference volume was predicted at the long side (186 ± 343.9 mm3) rather than the short side (54.4 ± 124.4 mm3) in Group 3 (p = 0.033). The bilateral difference in the volume of the interosseous interference of the osteotomized mandible was significantly correlated with the Me deviation (r = − 0.257, p = 0.009) and bilateral ramal inclination (r = 0.361, p < 0.001). The predictor variable that affected the volume of the osseous interference at each side was the amount of Me deviation (p = 0.010). Conclusion By using the 3D simulation system, the potential site of bony collision could be visualized and successfully reduced intraoperatively. Since the osseous interference can be existed on any side, unilaterally or bilaterally, 3D surgical simulation is necessary before surgery to predict the osseous interference and improve the ramal inclination.

      • KCI등재

        The Role of CD36 in Type 2 Diabetes Mellitus: β-Cell Dysfunction and Beyond

        문준성,Udayakumar Karunakaran,엘루말레이수마,정승민,원규장 대한당뇨병학회 2020 Diabetes and Metabolism Journal Vol.44 No.2

        Impaired β-cell function is the key pathophysiology of type 2 diabetes mellitus, and chronic exposure of nutrient excess could lead to this tragedy. For preserving β-cell function, it is essential to understand the cause and mechanisms about the progression of β-cells failure. Glucotoxicity, lipotoxicity, and glucolipotoxicity have been suggested to be a major cause of β-cell dysfunction for decades, but not yet fully understood. Fatty acid translocase cluster determinant 36 (CD36), which is part of the free fatty acid (FFA) transporter system, has been identified in several tissues such as muscle, liver, and insulin-producing cells. Several studies have reported that induction of CD36 increases uptake of FFA in several cells, suggesting the functional interplay between glucose and FFA in terms of insulin secretion and oxidative metabolism. However, we do not currently know the regulating mechanism and physiological role of CD36 on glucolipotoxicity in pancreatic β-cells. Also, the downstream and upstream targets of CD36 related signaling have not been defined. In the present review, we will focus on the expression and function of CD36 related signaling in the pancreatic β-cells in response to hyperglycemia and hyperlipidemia (ceramide) along with the clinical studies on the association between CD36 and metabolic disorders.

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