Effects of electrolytes variation on formation of oxide layers of 6061 Al alloys by plasma electrolytic oxidation

Plasma electrolytic oxidation(PEO) processes were carried out to produce ceramic layers on 6061 aluminum substrates in four kinds of electrolytes such as silicate and aluminate solution with and without sodium fluorosilicate.The PEO processes were carried out under a hybrid voltage(260 V DC combined with 200 V,60 Hz AC amplitude) at room temperature for 5 min.The composition,microstructure and element distribution analyses of the PEO-treated layers were carried out by XRD and SEM & EDS.The effect of the electrolyte contents on the growth mechanism,element distribution and properties of oxide layers were studied.It is obvious that the layers generated in aluminate solutions show smoother surfaces than those in silicate solutions.Moreover,an addition of fluorine ion can effectively control the layer porosity;therefore,it can enhance the properties of the layers.

Improvement of erectile function by Korean red ginseng （Panax ginseng） in a male rat model of metabolic syndrome

The seriousness of metabolic syndrome is not due to the disease itself but its promotion of other diseases, such as erectile dysfunction and cardiovascular and cerebrovascular diseases. We investigated the effects of Korean red ginseng （KRG, Panax ginseng） extract on erectile function in a rat model of metabolic syndrome. We divided the rats into three groups： control, metabolic syndrome＋normal saline （N/S） and metabolic syndrome ＋ KRG. To determine the occurrence of metabolic syndrome in all groups, body weight and various biochemical parameters （e.g., blood glucose, insulin, cholesterol） were measured, and the intra-abdominal glucose tolerance test was performed. To investigate penile erection, the peak intracavernosal pressure （ICP）, mean arterial pressure （MAP） and Masson＇s trichrome stain were evaluated. Erectile function was also investigated by measuring the cyclic guanosine monophosphate （cGMP） levels of the corpus cavernosum. We found that the various biochemical parameters and body weight were similar in the metabolic syndrome＋KRG group and the control group, although the values were slightly higher. The peak ICP/MAP ratio of the metabolic syndrome＋N/S group was markedly decreased compared to the other groups. The cGMP level of the corpus cavernosum in the metabolic syndrome＋N/S group was significantly lower than that of the other groups. As demonstrated in this model of metabolic syndrome with erectile dysfunction, KRG may improve erectile function.

Proto-oncogenic H-Ras, K-Ras, and N-Ras are involved in muscle differentiation via phosphatidylinositol 3-kinase

Oncogenic H-Ras G12V and its variants have been shown to inhibit muscle differentiation. However, the role of proto-oncogenic Ras （c-Ras） in muscle differentiation remains unclear. The active GTP-bound form of Ras has been known to associate with diverse effectors including Raf, phosphatidylinositol 3-kinase （PI3K）, RaI-GDS, and other molecules to transmit downstream signals. We hypothesize that c-Ras may stimulate muscle differentiation by selectively activating PI3K, an important mediator for muscle differentiation. In our experiments, inhibition of c-Ras by farnesyltransferase inhibitors and a dominant negative form of H-Ras （Ras S17N） suppressed muscle differentiation. Consistently, individual knockdown of H-Ras, K-Ras, and N-Ras by siRNAs all blocked muscle differentiation. Interestingly, we found that c-Ras preferentially interacts with PI3K rather than its major binding partner c-Raf, during myogenic differentiation, with total c-Ras activity remaining unchanged. PI3K and its downstream myogenic pathway, the Nox2/NF-kB/inducible nitric oxide synthase （iNOS） pathway, were found to be suppressed by inhibition of c-Ras activity during differentiation. Furthermore, expression of a constitutively active form of PI3K completely rescued the differentiation block and reactivated the Nox2/NF-kB/iNOS pathway in c-Ras-inhibited cells. On the ba- sis of our results, we conclude that contrary to oncogenic Ras, proto-oncogenic H-Ras, K-Ras, and N-Ras are directly involved in the promotion of muscle differentiation via PI3K and its downstream signaling pathways. In addition, PI3K pathway activation is associated with a concurrent suppression of the otherwise predominantly activated Raf/ Mek/Erk pathway.