Konkuk University

About: Konkuk University is a education organization based out in Seoul, South Korea. It is known for research contribution in the topics: Population & Apoptosis. The organization has 13405 authors who have published 27027 publications receiving 506313 citations.

How to improve the success rate of mouse cloning technology.

Abstract: It has now been 13 years since the first cloned mammal Dolly the sheep was generated from somatic cells using nuclear transfer (SCNT). Since then, this technique has been considered an important tool not only for animal reproduction but also for regenerative medicine. However, the success rate is still very low and the mechanisms involved in genomic reprogramming are not yet clear. Moreover, the NT technique requires donated fresh oocyte, which raises ethical problems for production of human cloned embryo. For this reason, the use of induced pluripotent stem cells for genomic reprogramming and for regenerative medicine is currently a hot topic in this field. However, we believe that the NT approach remains the only valid way for the study of reproduction and basic biology. For example, only the NT approach can reveal dynamic and global modifications in the epigenome without using genetic modification, and it can generate offspring from a single cell or even a frozen dead body. Thanks to much hard work by many groups, cloning success rates are increasing slightly year by year, and NT cloning is now becoming a more applicable method. This review describes how to improve the efficiency of cloning, the establishment of clone-derived embryonic stem cells and further applications.

Endogenous IL-32 Controls Cytokine and HIV-1 Production

Abstract: IL-32, a proinflammatory cytokine that activates the p38MAPK and NF-kappaB pathways, induces other cytokines, for example, IL-1beta, IL-6, and TNF-alpha. This study investigated the role of endogenous IL-32 in HIV-1 infection by reducing IL-32 with small interfering (si)RNA in freshly infected PBMC and in the latently infected U1 macrophage cell line. When PBMC were pretreated with siRNA to IL-32 (siIL-32), IL-6, IFN-gamma, and TNF-alpha were reduced by 57, 51, and 36%, respectively, compared with scrambled siRNA. Cotransfection of NF-kappaB and AP-1 reporter constructs with siIL-32 decreased DNA binding of these transcription factors by 42 and 46%, respectively. Cytokine protein array analysis revealed that the inhibitory activity of siIL-32 primarily targeted Th1 and proinflammatory cytokines and chemokines, e.g., MIP-1alpha/beta. Unexpectedly, HIV-1 production (as measured by p24) increased 4-fold in these same PBMC when endogenous IL-32 was reduced. Because IFN-gamma was lower in siIL-32-treated PBMC, we blocked IFN-gamma bioactivity, which enhanced the augmentation of p24 by siIL-32. Furthermore, siIL-32 reduced the natural ligands of the HIV-1 coreceptors CCR5 (MIP-1alpha/beta and RANTES) and CXCR4 (SDF-1). Inhibition of endogenous IL-32 in U1 macrophages also increased HIV-1. When rhIL-32gamma was added to these cells, p24 levels fell by 72%; however, in the same cultures IFN-alpha increased 4-fold. Blockade of IFN-alpha/beta bioactivity in IL-32gamma-stimulated U1 cells revealed that IFN-alpha conveys the anti-HIV-1 effect of rhIL-32gamma. In summary, depletion of endogenous IL-32 reduced the levels of Th1 and proinflammatory cytokines but paradoxically increased p24, proposing IL-32 as a natural inhibitor of HIV-1.

Carbon dioxide capture and bioenergy production using biological system – A review

Abstract: With the growing use of fossil fuels and industrial activity, the amount of carbon dioxide (CO2) emission is continuously increasing and is considered a primary contributor to climate change. CO2 emissions from stationary resources (coal fire, cement plants, and other industry) can be reduced by using various carbon capture and sequestration (CCS) technologies. In this article, recent advancements in various biological methods (i.e., carbonic anhydrase (CA), hydrogenation of CO2 to formate, reduction of CO2 to methane, CO2 conversion into methanol by enzyme cascade, and the role of RuBisCo enzyme) that have been reported for CO2 capture are discussed, along with their advantages and limitations. A brief overview of other physicochemical (absorption, adsorption, cryogenic, and membrane) technologies is also provided. Although biological methods are ecofriendly and can be performed under ambient conditions, these approaches are still not cost effective, as the reactions require cofactors, and the enzymes lose activity when exposed to hot flue gas and ionic liquids. Most captured CO2 is stored by mineralization using a geological and ocean storage method without providing any economic benefit. It is a question of interest as to how we can utilize CO2 and generate revenue. Utilization of CO2 as a feedstock to produce bioenergy is a possible approach. Various microbes capable of utilizing CO2 as feedstock and producing biofuels (biodiesel and bioalcohol) have been reported. These two technologies, i.e., CO2 capture and bioconversion of CO2 into bioenergy, can be integrated to develop a process that not only mitigates CO2 effects on the environment but also solves energy problems while generating revenue.

Revision and update on clinical practice guideline for liver cirrhosis.

Abstract: Liver cirrhosis (LC) is a disease with a high rate of prevalence and one of the most common causes of mortality in the Republic of Korea (hereafter "Korea"). In Korea, the main etiologies of LC have been found to be chronic hepatitis B (CHB), alcohol, and chronic hepatitis C (CHC). In patients with complications such as ascites, variceal bleeding, and encephalopathy, the 5-year survival rates were 32%, 21%, and 40%, respectively, reflecting the poor prognosis of patients with LC. Consequently, a clinical practice guideline appropriate for the medical milieu of Korea is important for both patients and clinicians. In 2005, the Korean Association for the Study of the Liver established a guideline for the treatment of LC that is now widely used. However, it is currently necessary to revise and update the clinical practice guideline based on new evidence over the past 6 years regarding the diagnosis, treatment, and prevention of LC. Therefore, the Korean Association for the Study of the Liver undertook a revision and update of the clinical practice guideline co-organized by the Liver Cirrhosis Clinical Research Center. This guideline was based on an interdisciplinary (hepatology, radiology, pathology, and preventive medicine) approach. A panel of experts selected by the Korean Association for the Study of the Liver and Liver Cirrhosis Clinical Research Center met several times to discuss and write this guideline during 2005-2011. This guideline was written in light of published studies retrieved from MEDLINE, EMBASE, and Cochrane Library. The panel aimed to address 5 subjects: diagnosis of LC, anti-fibrotic therapy for LC, variceal bleeding, ascites, and hepatic encephalopathy. The evidence and recommendations made in this guideline have been graded according to the GRADE (Grading of Recommendations Assessment Development and Evaluation) system. The strength of evidence has been classified into 3 levels: A (high-quality evidence), B (moderate-quality evidence), and C (low-quality evidence). The strength of recommendation has been classified into 2 categories: strong and weak (Table 1). Where there was no clear evidence, the recommendations were based on the consensus expert opinion(s) in literature and that of the writing committee. Table 1 Grading evidence and recommendations 1. Diagnosis of LC LC is a pathologically defined disease, and is clinically classified as compensated and decompensated LC. Decompensated LC includes cases with ascites, variceal bleeding, hepatic encephalopathy, or jaundice. Image studies for diagnosing LC are CT, abdominal ultrasound, and MRI. Typical findings of these images are nodular liver surface, splenomegaly, and the presence of intra-abdominal collateral vessels, which mean increasing portal venous pressure. Although there are not established criteria for the diagnosis of compensated LC, imaging studies may be helpful for the diagnosis of LC b y integrating laboratory findings such as albumin, bilirubin, or prothrombin time and platelet values. 1-1. Diagnostic approach-patient history, physical examination, and laboratory tests When dealing with patients with LC, evaluation of the cause, severity, and stage is the first step. In patients with chronic liver disease, history taking (drug use, blood transfusion, or alcohol use), physical examination (jaundice, ascites, spider angioma, hepatomegaly, or splenomegaly), and symptom such as fatigue from hepatitis should be assessed. In patients with LC, a whole blood test including platelet count, liver function test (albumin, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, and gamma glutamyl transpeptidase), prothrombin time, abdominal ultrasound, abdominal CT, and endoscopy should be carried out to confirm the presence or absence of cirrhosis. In addition, laboratory tests for hepatitis B or C virus infection are needed for the evaluation of its cause. Generally, the Child-Pugh score is used to assess the severity of LC. In clinical practice for the diagnosis of LC, findings of portal hypertension such as ascites, hepatic encephalopathy, or varices, imaging findings, and laboratory findings are common diagnostic tools. Recently, it was found that nodularity of the liver surface, a platelet count of less than 100,000/mm3, albumin less than 3.5 g/dL, and an international normalized ratio of 1.3 or more are related to the presence of LC. Presence of one condition of these findings showed a specificity of 90.42% and a sensitivity of 61.11%.1

Analytical design model for a piezo-composite unimorph actuator and its verification using lightweight piezo-composite curved actuators

Abstract: This paper describes an analytical design model for a layered piezo-composite unimorph actuator and its numerical and experimental verification using a LIPCA (lightweight piezo-composite curved actuator) that is lighter than other conventional piezo-composite type actuators. The LIPCA is composed of top fiber composite layers with high modulus and low CTE (coefficient of thermal expansion), a middle PZT ceramic wafer, and base layers with low modulus and high CTE. The advantages of the LIPCA design are to replace the heavy metal layer of THUNDER by lightweight fiber-reinforced plastic layers without compromising the generation of high force and large displacement and to have design flexibility by selecting the fiber direction and the number of prepreg layers. In addition to the lightweight advantage and design flexibility, the proposed device can be manufactured without adhesive layers when we use a resin prepreg system. A piezo-actuation model for a laminate with piezo-electric material layers and fiber composite layers is proposed to predict the curvature and residual stress of the LIPCA. To predict the actuation displacement of the LIPCA with curvature, a finite element analysis method using the proposed piezo-actuation model is introduced. The predicted deformations are in good agreement with the experimental ones.