In the present paper a variable-bias digital differential relay for power transformers protection is proposed. The amount of bias is varied linearly with the value of through current (mean of the currents entering and leaving the transformer). http://www.timberlandbootsireland.nu To take care of mismatch between CT ratios on primary and secondary sides of the power transformer, secondary currents of CT are corrected using a precalculated correction factor for the power transformer tap in operation. In the event of an abnormal operation, a fault discriminant based on fundamental, second and fifth harmonic components of differential current is used.timberlandbootsireland It provides discrimination between faults and magnetizing inrush /overexcitation copditions. Trip and indication signals arc issued in the former case, while only an indication is… given in the latter case.The relay scheme is simulated on a personal computer. https://en.wikipedia.org/wiki/Timberland The advantage of the proposed scheme is its ability to detect even low-level internal faults, which may not be detected by a fixed-bias relay. The relay is restrained from operations on magnetizing inrush and overexcitation. The proposed relay is stable on those heavy through faults on which a fixed-bias relay may operate.
Colorectal cancer is one of the most common malignancies in the world.Overactivity of phosphatidylinositol 3-kinase (PI3K) is frequently detected incolorectal carcinoma. PI3K signaling plays a pivotal role in intracellular signaltransduction pathways involved in cell growth, Timberland pro work boots ireland cellular transformation, and tumorigenesis.To specifically inhibit PI3K activity in colorectal cancer cells, we constructeda siRNA against the PI3K regulatory subunit p85α and transfected it into LoVoand SW480 cells. In the present study, treatment of colorectal cancer cells withPI3K p85α-specific siRNA inhibited cell proliferation, induced G1 phase cell cyclearrest and sensitized colorectal cancer cells to 5-FU-induced apoptosis. Furthermore,depletion of PI3K p85α resulted in significant activation of three Forkhead… boxclass O (FoxO) transcription factors, which inhibited the expression of cyclinD1, cdk4 and induced expression of p27/Kip1. http://www.timberlandbootsireland.nu Activation of FoxO transcriptionfactors also increased the expression of FasL. timberlandbootsireland Thus, our results indicate thatsiRNA-mediated gene silencing of PI3K p85α may be a useful therapeutic strategyfor colorectal carcinoma.
Squamous cell carcinoma of the head and neck (HNSCC) is the most commonneoplasm arising in the upper aerodigestive tract. Unfortunately, the survivalfor this type of cancer has not improved significantly in the past 25 years. Toenhance the survival rate multimodal therapy regimens have been set up. In theseregimens chemotherapy plays a pivotal role in the majority of advanced cases.Transmembrane protein- tyrosine kinases (PTK) are fundamental elements of thesignal transduction. In consequence, they might be promising targets for cancertherapy. http://www.timberlandbootsireland.nu Imatinib (STI 571) was originally designed to inhibit the BCR-ABL tyrosinekinase in chronic myeloid leukemia. But imatinib also has an inhibitory impacton the PTK receptor c-kit and on its PTK activity. Furthermore, growth and invasionof HNSCC are… strongly influenced by the extracellular matrix (ECM). The ECM isaltered by matrix metalloproteinases (MMP). timberlandbootsireland In this study, we incubated differentHNSCC cell lines with rising concentrations of imatinib and/or carboplatin. Afteran incubation time of up to 10 days, we evaluated c-kit, MMP-2 and MMP-14 by ELISAtechniques and immunohistochemical methods. Timberland pro boots ireland Especially the combination of 7.5μmol carboplatin with 30 μmol imatinib resulted in a significant decrease in MMP-2expression in all observed cell lines.