Effect of Cyclic Shear Fatigue under Magnetic Field on Natural Rubber Composite as Anisotropic Magnetorheological Elastomers.

With the development and wide applicability of rubber materials, it is imperative to determine their performance under various conditions. In this study, the effect of cyclic shear fatigue on natural-rubber-based anisotropic magnetorheological elastomer (MRE) with carbonyl iron particles (CIPs) was investigated under a magnetic field. An anisotropic MRE sample was prepared by moulding under a magnetic field. Cyclic shear fatigue tests were performed using a modified electromechanical fatigue system with an electromagnet. The storage modulus (G') and loss factor in the absence or presence of a magnetic field were measured using a modified dynamic mechanical analysis system. Under a magnetic field, fatigue exhibited considerable effects to the MRE, such as migration and loss of magnetised CIPs and suppressed increase in stiffness by reducing the energy loss in the strain cycle. Therefore, the G' of the MRE after fatigue under a magnetic field was lower than that after fatigue in the zero field. The performance of the MRE, such as absolute and relative magnetorheological effects, decreased after subjecting to cyclic shear fatigue. In addition, all measured results exhibited strain-dependent behaviour owing to the Payne effect.

Design of Self-Healing EPDM/Ionomer Thermoplastic Vulcanizates by Ionic Cross-Links for Automotive Application.

The development of smart elastomeric materials with inherent self-repairing abilities after mechanical damage has important technological and scientific implications, particularly in regard to the durability and life cycle of rubber products. The interest in self-healing materials for automotive applications is rapidly growing along with the increasing importance of vehicle scratch quality and quantity. The creation of a reversible network by noncovalent ionic cross-linking in elastomer/rubber blends is an effective approach to generate the self-healing phenomenon, with reprocessing and recycling properties. In this work, thermoplastic vulcanizates (TPVs) were prepared using ethylene-propylene-diene (EPDM) polymers and high-acid-containing thermoplastic ionomers. Along with the general EPDM, maleic anhydride grafted EPDM (EPDM-g-MAH) was also used for the preparation of the TPVs. The strategy was based on a simple ionic crosslinking reaction between the carboxyl groups present in the ionomer and zinc oxide (ZnO), where the formation of reversible Zn2+ salt bondings exhibits the self-healing behavior. The heterogeneous blending of EPDM and ionomers was also used to investigate the thermal and mechanical properties of the TPVs. The experimental findings were further supported by the surface morphology of the fracture surfaces viewed using microscopy. The self-healing behavior of the TPVs has been identified by scratch resistance testing, where the EPDM-g-MAH TPVs showed excellent healing efficiency of the scratch surface. Therefore, this work provides an efficient approach to fabricate new ionically cross-linked thermoplastic vulcanizates with excellent mechanical and self-repairing properties for the skins of automotive interior door trims and instrument panel applications.

Springtail-inspired superomniphobic surface with extreme pressure resistance.

Both high static repellency and pressure resistance are critical to achieving a high-performance omniphobic surface. The cuticles of springtails have both of these features, which result from their hierarchical structure composed of primary doubly reentrant nanostructures on secondary microgrooves. Despite intensive efforts, none of the previous studies that were inspired by the springtail were able to simultaneously achieve both high static repellency and pressure resistance because of a general trade-off between these characteristics. We demonstrate for the first time a springtail-inspired superomniphobic surface displaying both features by fabricating a hierarchical system consisting of serif-T-shaped nanostructures on microscale wrinkles, overcoming previous limitations. Our biomimetic strategy yielded a surface showing high repellency to diverse liquids, from water to ethanol, with a contact angle above 150°. Simultaneously, the surface was able to endure extreme pressure resulting from the impacts of drops of water and of ethylene glycol with We >> 200, and of ethanol with We ~ 53, which is the highest pressure resistance ever reported. Overall, the omniphobicity of our springtail-inspired fabricated system was found to be superior to that of the natural springtail cuticle itself.

Historical difference between traditional Korean medicine and traditional Chinese medicine.

BACKGROUND: Although traditional Korean medicine (TKM) has been influenced by traditional Chinese medicine (TCM), it has developed distinctive features. Around the tenth century, Chinese medical books were introduced to Korea. In those days, Koreans started movement to develop its own medical system. METHODS: We reviewed Korean and Chinese medical literatures, and analysed the characteristics between two medical systems. RESULTS: In the early 17th century, Dongeuibogam was published by Dr Joon Hur. He provided a turning point to establish Korean medical system independent from TCM. TKM emphasizes specific characteristics of the individual who suffered from the disease, rather than single symptom. The concept was elaborated by Dr Jae Ma Lee who published Dongeuisusaebowon in the early 20th century. CONCLUSION: Through historical development, TKM has established the unique characteristic and modality as the whole-person-centered medicine.

Cytoprotective effect of Panax ginseng on gallic acid-induced toxicity in TM3 mouse Leydig cells.

Our previous study had demonstrated cytotoxicity of gallic acid on testicular cells with increasing the intracellular production of hydrogen peroxide. In the present study, the Panax ginseng root aqueous extract showed the cytoprotective effect on gallic acid-induced toxicity in TM3 mouse Leydig cells with decreasing the intracellular production of hydrogen peroxide.

[The academic trend of Oriental medicine during the Japanese colonial period as observed through the publication of medical books].

This thesis examines the academical trend of Oriental Medicine in the Japanese colonial period observed through medical books published during the Japanese colonial period. This is a period in which Western Medicine was introduced, and due to the lean-to-one-side policy by the Japanese, Western Medicine became the mainstream medical science while Oriental Medicine was pushed to the outskirts. Even after all this, the academic activity was flourishing during this period compared to any other periods. This article is divided into various chapters each with its own theme in order to understand the academic trend of Oriental Medicine during the Japanese colonial period. Focusing on the publication of medical books, this article is divided and observed according to various themes such as the study of Dong-Eui-Bo-Gam (see text), the study of Bang-Yak-Hap-Pyeun (see text), the study of Sang-Han-Ron (see text), the study of Sa-sang (see text) constitutional medicine, the study of Eui-Hak-Ip-Mun (see text), the study about Bu-Yang-Ron (see text), On-Bo-Ron (see text), and pediatrics, compromise between Western and Oriental Medicine, the study of experience medicine, the study of acupuncture and moxibustion, and etc.

Isolation of two distinct populations of recombinant antibody molecules specific for rat malonyl-CoA decarboxylase from a semi-synthetic human scFv display library using Ex-phage system.

A semi-synthetic human scFv phage display library by randomizing amino acid residues at CDR3H was constructed using pIGT3 phagemid vector. Recombinant phages were rescued by super-infecting the JS5 E. coli library stock with Ex-phage, the mutant M13KO7 helper phage containing amber mutations at gIII. The library was composed of 2 x 10(8) independent clones, and selected for the specific binders against malonyl-CoA decarboxylase (MCD) by panning. Five soluble scFv clones specific for MCD were finally identified and classified into two groups based on the difference in their binding pattern to MCD. Two clones (M4 and M8) showed good binding reactivity to MCD in ELISA but not in Western blot, whereas, the rest three clones (M23, M28 and M41) reacted to the antigen in Western blot but not in ELISA implying they bound to somewhat different epitopes on MCD. DNA sequencing analysis of M4, M8, M23 and M28 showed that VH of all clones were belonged to VH3 subgroup. On the other hand, M4 and M8 utilized VLkappa subgroup I, and M23 and M28 used VLkappa subgroup IV, suggesting that difference in binding pattern between M4/M8 and M23/M28 against MCD might come from the different VL gene utilization. In conclusion, human monoclonal scFv antibodies specific for MCD were successfully isolated and we demonstrated that distinct populations of recombinant antibodies specific to the target antigen could be isolated by Ex-phage system.

Preexisting intimal hyperplasia of radial artery is associated with early failure of radiocephalic arteriovenous fistula in hemodialysis patients.

BACKGROUND: The radiocephalic arteriovenous fistula (AVF), which provides the best vascular access for hemodialysis, continues to have a high incidence of early failure. Intimal hyperplasia (IH) of the radial artery is observed commonly in uremic patients before hemodialysis, but the impact of this preexisting IH on the early failure of radiocephalic AVFs has not been reported yet. Therefore, we designed this study to: (1) investigate clinical risk factors for IH, and (2) determine whether preexisting IH of the radial artery is associated with early failure of a radiocephalic AVF. METHODS: Specimens from the radial artery were obtained during the radiocephalic AVF operation. IH was measured with trichrome staining, and AVF patency was prospectively followed up for 12 months after the operation. RESULTS: Of the 59 patients, 45 patients had evidence of IH in their radial artery (76.2%). Patients with IH (n = 45) were older than those without IH (n = 14; 58 +/- 12 versus 44 +/- 17 years; P = 0.003). The incidence of diabetes mellitus in patients with IH was greater than that in patients without IH (60.0% versus 28.6%; P = 0.004). Of the 57 patients, except for 2 patients who died before the end point of the study with patent AVFs, fistula failure was observed only in patients with IH (22 of 44 patients; 50% versus 0%; P < 0.001). The intima was thicker in the failed-AVF group than the patent-AVF group (93.1 +/- 37.5 versus 45.6 +/- 17.4 micrometer P < 0.001). CONCLUSION: This study suggests that early failure of radiocephalic AVFs in hemodialysis patients is closely associated with preexisting IH of the radial artery.

Regulatory effects of cytokine production in atopic allergic reaction by gammi-danguieumja.

Gammi-danguieumja (GD) is clinically used in South Korea for treating atopic dermatitis. However, its effects in experimental models remain unknown. We investigated a possible effect of GD on cytokines production using human T cell line (MOLT-4) or human mast cell line. As a result, GD (0.01 mg/mL)-containing medium in stimulated culture supernatants increased IL-2 and IFN-gamma, and decreased IL-4 secretion in MOLT-4. GD (0.01-1 mg/mL)-containing medium in stimulated culture supernatants dose-dependently and significantly decreased IL-8, IL-13, and tumor necrosis factor-alpha secretion on the phorbol 12-myristate 13-acetate and A23187-stimulated HMC-1. In addition, GD inhibited histamine release from activated mast cells. These results suggest that GD contributes to the regulation of atopic allergic reactions.

Development of two quantitative real-time PCR diagnostic kits for HPV isolates from Korea.

Viral pathogens, alongside other pathogens, have major effects on crustacean aquaculture. Hepatopancreatic parvovirus (HPV) is an emerging virus in the shrimp industry and has been detected in shrimp farms worldwide. The HPV genome has greater diversity than other shrimp viruses owing to its wide host range and geographical distribution. Therefore, developing diagnostic tools is essential to detect even small copy numbers from the target region of native HPV isolates. We have developed two easy to use quantitative real-time PCR kits, called Green Star and Dual Star, which contain all of the necessary components for real-time PCR, including HPV primers, using the primers obtained from the sequences of HPV isolates from Korea, and analyzed their specificity, efficiency, and reproducibility. These two kits could detect from 1 to 1 × 10(9) copies of cloned HPV DNA. The minimum detection limits obtained from HPV-infected shrimp were 7.74 × 10(1) and 9.06 × 10(1) copies in the Green Star and Dual Star assay kits, respectively. These kits can be used for rapid, sensitive, and efficient screening for HPV isolates from Korea before the introduction of postlarval stages into culture ponds, thereby decreasing the incidence of early development of the disease.

Identification of campesterol from Chrysanthemum coronarium L. and its antiangiogenic activities.

Campesterol, a plant sterol in nature, is known to have cholesterol lowering and anticarcinogenic effects. Since angiogenesis is essential for cancer, it was surmised that an antiangiogenic effect may be involved in the anticancer action of this compound. This study investigated the effect of campesterol on basic fibroblast growth factor (bFGF)-induced angiogenesis in vitro in human umbilical vein endothelial cells (HUVECs) and an in vivo chorioallantoic membrane (CAM) model. Campesterol isolated from an ethylacetate fraction of Chrysanthemum coronarium L. showed a weak cytotoxicity in non-proliferating HUVECs. Within the non-cytotoxic concentration range, campesterol significantly inhibited the bFGF-induced proliferation and tube formation of HUVECs in a concentration-dependent manner, while it did not affect the motility of HUVECs. Furthermore, campesterol effectively disrupted the bFGF-induced neovascularization in chick chorioallantoic membrane (CAM) in vivo. Taken together, these results support a potential antiangiogenic action of campesterol via an inhibition of endothelial cell proliferation and capillary differentiation.

Carditis is associated with Helicobacter pylori-induced gastritis and not reflux esophagitis.

Pathogenesis of chronic inflammation at the gastric cardia is not yet clear. It is controversial whether cardiac-type mucosa is normal structure at the cardiac region. Therefore, we studied the existence of correlations between carditis, infection, and gastroesophageal reflux disease, and determined the prevalence of cardiac mucosa at the endoscopically defined cardiac region. Gastric biopsy specimens were analyzed from 27 patients with reflux esophagitis and 30 subjects without reflux esophagitis. Carditis was not associated with reflux esophagitis, but with infection. Moreover, the degree of gastritis and atrophy at the cardia were closely related to those of the antrum and body. Cardiac mucosa was not always present in the endoscopically defined cardiac region, and its prevalence was positively correlated with gastritis and atrophy grade of the cardia and age. In conclusion, -induced pangastritis may lead to the development of carditis, which is associated with occurrence of cardiac-type mucosa at the cardiac region.

Reflux esophagitis facilitates low Helicobacter pylori infection rate and gastric inflammation.

BACKGROUND: Helicobacter pylori is regarded as an important pathogen in upper gastrointestinal diseases. However, little is known about the relationship between H. pylori infection and reflux esophagitis. Therefore, an investigation was undertaken in Korean subjects regarding the incidence of H. pylori infection, and a histopathological study of reflux esophagitis was also carried out. METHODS: Analysis of gastric biopsy specimens was conducted for 73 patients with reflux esophagitis and 132 control subjects without reflux esophagitis. The H. pylori infection was assessed by using rapid urease test and the immunohistochemical method, and gastric mucosal morphologic change was analyzed according to the updated Sydney system. RESULTS: The prevalence of H. pylori infection was significantly lower in patients with reflux esophagitis than in the non-reflux group. Grade of inflammation and glandular atrophy in the antrum and body were higher in patients in the non-reflux group compared with those in the reflux esophagitis group. CONCLUSIONS: It is suggested that H. pylori infection decreases the risk of reflux esophagitis by inducing atrophic gastritis.