The nature of the progenitor of the M31 north-western stream: globular clusters as milestones of its orbit

We examine the nature, possible orbits and physical properties of the progenitor of the north-western stellar stream (NWS) in the halo of the Andromeda galaxy (M31). The progenitor is assumed to be an accreting dwarf galaxy with globular clusters (GCs). It is, in general, difficult to determine the progenitor\u27s orbit precisely because of many necessary parameters. Recently, Veljanoski et al. reported five GCs whose positions and radial velocities suggest an association with the stream. We use these data to constrain the orbital motions of the progenitor using test-particle simulations. Our simulations split the orbit solutions into two branches according to whether the stream ends up in the foreground or in the background of M31. Upcoming observations that will determine the distance to the NWS will be able to reject one of the two branches. In either case, the solutions require that the pericentric radius of any possible orbit be over 2 kpc. We estimate the efficiency of the tidal disruption and confirm the consistency with the assumption for the progenitor being a dwarf galaxy. The progenitor requires the mass ≳ 2 × 106 M⊙ and half-light radius ≳ 30 pc. In addition, N-body simulations successfully reproduce the basic observed features of the NWS and the GCs\u27 line-of-sight velocities

The Japanese space gravitational wave antenna; DECIGO

DECi-hertz Interferometer Gravitational wave Observatory (DECIGO) is the future Japanese space gravitational wave antenna. DECIGO is expected to open a new window of observation for gravitational wave astronomy especially between 0.1 Hz and 10 Hz, revealing various mysteries of the universe such as dark energy, formation mechanism of supermassive black holes, and inflation of the universe. The pre-conceptual design of DECIGO consists of three drag-free spacecraft, whose relative displacements are measured by a differential Fabry– Perot Michelson interferometer. We plan to launch two missions, DECIGO pathfinder and pre- DECIGO first and finally DECIGO in 2024

Expression of paclitaxel-inactivating CYP3A activity in human colorectal cancer: implications for drug therapy

Cytochrome P450 3A is a drug-metabolising enzyme activity due to CYP3A4 and CYP3A5 gene products, that is involved in the inactivation of anticancer drugs. This study analyses the potential of cytochrome P450 3A enzyme in human colorectal cancer to impact anticancer therapy with drugs that are cytochrome P450 3A substrates. Enzyme activity, variability and properties, and the ability to inactivate paclitaxel (taxol) were analysed in human colorectal cancer and healthy colorectal epithelium. Cytochrome P450 3A enzyme activity is present in healthy and tumoral samples, with a nearly 10-fold interindividual variability. Nifedipine oxidation activity±s.d. for colorectal cancer microsomes was 67.8±36.6 pmol min−1 mg−1. The Km of the tumoral enzyme (42±8 μM) is similar to that in healthy colorectal epithelium (36±8 μM) and the human liver enzyme. Colorectal cancer microsomes metabolised the anticancer drug paclitaxel with a mean activity was 3.1±1.2 pmol min−1 mg−1. The main metabolic pathway is carried out by cytochrome P450 3A, and it is inhibited by the cytochrome P450 3A-specific inhibitor ketoconazole with a KI value of 31 nM. This study demonstrates the occurrence of cytochrome P450 3A-dependent metabolism in colorectal cancer tissue. The metabolic activity confers to cancer cells the ability to inactivate cytochrome P450 3A substrates and may modulate tumour sensitivity to anticancer drugs

Synthesis and bio-molecular study of (+)-N-Acetyl-α-amino acid dehydroabietylamine derivative for the selective therapy of hepatocellular carcinoma

BACKGROUND: The purpose of present work is to synthesize novel (+)-Dehydroabietylamine derivatives (DAAD) using N-acetyl-α-amino acid conjugates and determine its cytotoxic effects on hepatocellular carcinoma cells. METHODS: An analytical study was conducted to explore cytotoxic activity of DAAD on hepatocellular carcinoma cell lines. The cytotoxicity effect was recorded using sulforhodamine B technique. Cell cycle analysis was performed using Propidium Iodide (PI) staining. Based on cell morphology, anti growth activity and microarray findings of DAAD2 treatment, Comet assay, Annexin V/PI staining, Immunoperoxidase assay and western blots were performed accoringly. RESULTS: Hep3B cells were found to be the most sensitive with IC(50) of 2.00 ± 0.4 μM against (+)-N-(N-Acetyl-L-Cysteine)-dehydroabietylamine as DAAD2. In compliance to time dependent morphological changes of low cellular confluence, detachment and rounding of DAAD2 treated cells; noticeable changes in G(2)/M phase were recorded may be leading to cell cycle cessation. Up-regulation (5folds) of TUBA1A gene in Hep3B cells was determined in microarray experiments. Apoptotic mode of cell death was evaluated using standardized staining procedures including comet assay and annexin V/PI staining, Immuno-peroxidase assay. Using western blotting technique, caspase dependant apoptotic mode of cell death was recorded against Hep3B cell line. CONCLUSION: It is concluded that a novel DAAD2 with IC(50) values less than 8 μM can induce massive cell attenuation following caspase dependent apoptotic cell death in Hep3B cells. Moreover, the corelation study indicated that DAAD2 may have vital influence on cell prolifration properties. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12885-016-2942-5) contains supplementary material, which is available to authorized users