Alteration of chromosome positioning during adipocyte differentiation

Chromosomes are highly restricted to specific chromosome territories within the interphase nucleus. The arrangement of chromosome territories is non-random, exhibiting a defined radial distribution as well as a preferential association with specific nuclear compartments, which indicates a functional role for chromosome-territory organization in the regulation of gene expression. In this report, we focus on changes in adipocyte differentiation that are related to a specific chromosomal translocation associated with liposarcoma tumorigenesis, t(12;16). We have examined the relative and radial positioning of the chromosome territories of human chromosomes 12 and 16 during adipocyte differentiation, and detected a close association between the territories of chromosomes 12 and 16 in differentiated adipocytes, an association not observed in preadipocytes. Although further studies are required to elucidate the underlying reasons for the adipocyte-specific translocation of chromosomes 12 and 16, our observations indicate that alteration of relative chromosome positioning might play a key role in the tumorigenesis of human liposarcomas. In addition, these results demonstrate the potential impact of higher order chromatin organization on the epigenetic mechanisms that control gene expression and gene silencing during cell differentiation

Mathematical Model of Ship Collision Probability

A mathematical model for estimating the probability of collision of ships passing through a uniform channel is proposed. The model takes into account the give-way motions of the encountered ships and the wake position characteristics under the given channel conditions such as width, length and centerline like buoys. The probability of collision is defined as the probability of an event where a ship fails to give way. Using this probability of collision, the “Collision Risk of Channel” is defined. The proposed model is examined by the collision statistics of some channels and straits in Japan. According to these statistics, the present model gives a good estimation of the collision risk of a channel. Since the proposed model takes account of traffic characteristics such as traffic volume, ship size distribution, and sailing velocity distribution, as well as channel conditions such as width, length and centerline mark like buoys, the effects of their change or control on the probability of collision can be easily predicted. Therefore, the proposed model is quite useful for the engineering planning and design of any channel

Three Dimensional Magneto Hydrodynamical Simulations of Gravitational Collapse of a 15Msun Star

We introduce our newly developed two different, three dimensional magneto hydrodynamical codes in detail. One of our codes is written in the Newtonian limit (NMHD) and the other is in the fully general relativistic code (GRMHD). Both codes employ adaptive mesh refinement and, in GRMHD, the metric is evolved with the "Baumgarte-Shapiro-Shibata-Nakamura" formalism known as the most stable method at present. We did several test problems and as for the first practical test, we calculated gravitational collapse of a $15M_\odot$ star. Main features found from our calculations are; (1) High velocity bipolar outflow is driven from the proto-neutronstar and moves through along the rotational axis in strongly magnetized models; (2) A one-armed spiral structure appears which is originated from the low-$|T/W|$ instability; (3) By comparing GRMHD and NMHD models, the maximum density increases about $\sim30$ in GRMHD models due to the stronger gravitational effect. These features agree very well with previous studies and our codes are thus reliable to numerical simulation of gravitational collapse of massive stars.Comment: Accepted by ApJS, 55 pages, 34 figure