Intergranular Corrosion and Microstructural Evolution in a Newly Designed Al-6Mg Alloy.

In this work, the microstructure and corrosion behavior of a novel Al-6Mg alloy were investigated. The alloy was prepared by casting from pure Al and Mg+Al2Ca master alloy. The ingots were homogenized at 420 °C for 8 h, hot-extruded and cold-rolled with 20% reduction (CR20 alloy) and 50% reduction (CR50 alloy). The CR50 alloy exhibited a higher value of intergranular misorientation due to a higher cold rolling reduction ratio. The average grain sizes were 19 ± 7 µm and 17 ± 9 µm for the CR20 and CR50 alloys, respectively. An intergranular corrosion (IGC) behavior was investigated after sensitization by a nitric acid mass-loss test (ASTM G67). The mass losses of both the CR20 and CR50 alloys were similar at early periods of sensitization, however, the CR20 alloy became more susceptible to IGC as the sensitization time increased. Grain size and ß phase precipitation were two critical factors influencing the IGC behavior of this alloy system.

Effects of Heat Treatment on Interfacial Behavior and Bonding Strength of Surface Activated Bonding Ti-Al Laminate.

The surface activated bonding (SAB) method generally has the advantage of high bonding strength, low contact resistance, and high microstructural stability at room temperature. In this study, Ti-Al laminates were produced by surface activated bonding with aluminum and titanium foils. Heat treatment was conducted at the temperature range from 200 to 550 °C in vacuum. The bonding strength Ti-Al laminates was measured by a peel test, and the interfacial characteristics were investigated microstructural observation. The results showed that the bonding strength was the highest with heat treatment at 400 °C, microstructure observation revealed that the bonding strength of the Ti-Al laminate was influenced by the interfacial characteristics.

Cystic duct variation detected by near-infrared fluorescent cholangiography during laparoscopic cholecystectomy.

Near-infrared fluorescent cholangiography (NIRFC) is an emerging technique for easy intraoperative recognition of biliary anatomy. We present a case of cystic duct variation detected by NIRFC which had a potential risk for biliary injury if not detected. A 32-year-old female was admitted to the Seoul St. Mary's Hospital for surgery for an incidental gallbladder polyp. We performed laparoscopic cholecystectomy with NIRFC. In fluorescence mode, a long cystic duct and an accessory short hepatic duct joining to the cystic duct were found and the operation was completed safely. The patient recovered successfully. NIRFC is expected to be a promising procedure that will help minimize biliary injury during laparoscopic cholecystectomy.

Versican expression in tumor epithelial cells is correlated with a good prognosis in gastric cancer.

BACKGROUND/AIM: Versican expression has been reported to have prognostic value in several cancers. The aim of the present study was to investigate the prognostic significance of versican expression in gastric cancer. MATERIALS AND METHODS: In total, 105 gastric cancer patients who received gastrectomy were included in the study. Versican expression in the epithelial and stromal components of the tumors was determined by immunohistochemistry. RESULTS: Versican was expressed in 21.0% of tumor epithelial cells and 44.8% of stromal cells. Patients with versican expression in tumor epithelial cells had significantly better 5-year disease-free (p=0.021) and overall (p=0.034) survival rates, whereas versican expression in stromal cells was not associated with disease-free (p=0.532) and overall (p=0.876) survival. Multivariate analysis showed that versican expression in tumor epithelial cells was an independent prognostic indicator for better clinical outcome in disease-free and overall survival. CONCLUSION: Versican expression in tumor epithelial cells predicts a good prognosis for gastric cancer patients.

Comparison of problematic internet and alcohol use and attachment styles among industrial workers in Korea.

The objective of this article is to fully understand Internet addiction, we aimed to compare the attachment styles and psychopathologies associated with problematic Internet use with those related to alcohol use. Through the participation of 141 male participants, the present study assessed problematic Internet and alcohol use, attachment, psychopathology, and demographic data via the use of self-rating questionnaires. We explored the significant predictors among avoidant and anxious attachments, depression, anxiety, and phobia to explain problematic Internet and alcohol use. The results showed that anxious attachment, depression, and anxiety could explain problematic alcohol use. In contrast, both anxious and avoidant attachment as well as depression and phobia explained problematic Internet use. Additionally, depression moderated the effects of avoidant attachment on problematic Internet use. We demonstrated that the interaction of attachment and psychopathology predicts problematic Internet use originating from an earlier stage of life than that associated with problematic alcohol use.

Gallic acid inhibits cell viability and induces apoptosis in human monocytic cell line U937.

In the present study, we investigated the effects of gallic acid (GA) (3,4,5-trihydroxybenzoic acid), a polyhydroxyphenolic compound, isolated from Rhus chinensis, on the human monocytic lymphoma cell line U937. In vitro experiments showed that treating U937 cells with various amounts of GA inhibited cell viability and induced apoptosis in a dose-dependent manner. In order to understand the mechanism by which GA induces apoptosis, we examined the gene expression of p53, nuclear factor κB (NF-κB), and inhibitor of NF-κB (I-κB) after treating the cells with GA and found that expression levels of the genes for p53 and NF-κB increased and that for I-κB decreased. The results obtained from western blotting with U937 cells showed up-regulation of NF-κB protein and down-regulation of proliferating cell nuclear antigen and I-κB protein. These results demonstrate that GA efficiently induces apoptosis in U937 cells and that GA is a potential chemotherapeutic agent against lymphoma.

Effects of isolated compounds from Catalpa ovata on the T cell-mediated immune responses and proliferation of leukemic cells.

Three compounds were isolated from the ethyl acetate soluble fraction of the methanolic extract of the leaves of Catalpa ovata (Bignoniaceae) through repeated column chromatography. We investigated the effects of these compounds on T cell-mediated responses for tumor surveillance and proliferation in U937, HL60, and Molt-4 leukemia cells. Compounds 1-3 inhibited proliferation of those cells in a dose-dependent manner. Compound 3 showed mild effect in Molt-4 cell cytotoxicity. Compound 3 enhanced gene expressions of p53 and IL-4, but decreased IL-2 and IFN-Gamma genes in Molt-4 cell. Our findings indicate that compound 3 may enhance T cell-mediated immune responses and anticancer properties.

Apoptosis-inducing effect of akebia saponin D from the roots of Dipsacus asper Wall in U937 cells.

Methanol extracts of the root of Dipsacus asper Wall (Dipsacaceae) were found to exhibit apoptosis-inducing activities in U937 (human monocyte-like histiocytic) cells. Investigation of the active n-BuOH fraction led to the isolation of akebia saponin D (ASD). Structure was established by spectroscopic methods. Treatment of U937 cells with ASD induced apoptosis in a dose dependent manner. ASD exerted strong cytotoxicity against human and murine leukemia cells. It is significantly increased the subG1 cell population and expression of p53 and Bax gene. And also ASD enhanced NO production from RAW264.7 macrophage cells. Taken together, these results strongly indicate that ASD may exert apoptosis-inducing activity via induction of apoptosis through activation chiefly via the nitric oxide and apoptosis-related p53 and Bax gene expression. These data provide scientific evidence that Dipsacus asper Wall can be useful as a chemopreventive agent.

Effect of the on/off cyclic modulation time ratio of C2H2/H2 flow on the low temperature deposition of carbon nanofilaments.

Low temperature (less than 600 degrees C) deposition of carbon nanofilaments (CNFs) could be achieved on the silicon oxide substrate by thermal chemical vapor deposition system. We used Fe(CO)5 as the catalyst precursor for CNFs formation. For the enhancement of CNFs formation density, the source gas flow was intentionally manipulated as the cyclic on/off modulation of C2H2/H2 flow during the initial deposition stage. The CNFs formation density on silicon oxide substrate could be much enhanced by the cyclic modulation process having the higher growing/etching time ratio (180/30 s). Furthermore, the lattice structures of CNFs developed into carbon nanotubes at the higher growing/etching time ratio (180/30 s) case. The solely hydrogen gas feeding (C2H2 flow off) time during the initial deposition stage seems to play an important role for the variation in the CNFs formation characteristics by the cyclic modulation process.