Zfp206 regulates ES cell gene expression and differentiation

Understanding transcriptional regulation in early developmental stages is fundamental to understanding mammalian development and embryonic stem (ES) cell properties. Expression surveys suggest that the putative SCAN-Zinc finger transcription factor Zfp206 is expressed specifically in ES cells [Zhang,W., Morris,Q.D., Chang,R., Shai,O., Bakowski,M.A., Mitsakakis,N., Mohammad,N., Robinson,M.D., Zirngibl,R., Somogyi,E. et al., (2004) J. Biol., 3, 21; Brandenberger,R., Wei,H., Zhang,S., Lei,S., Murage,J., Fisk,G.J., Li,Y., Xu,C., Fang,R., Guegler,K. et al., (2004) Nat. Biotechnol., 22, 707–716]. Here, we confirm this observation, and we show that ZFP206 expression decreases rapidly upon differentiation of cultured mouse ES cells, and during development of mouse embryos. We find that there are at least six isoforms of the ZFP206 transcript, the longest being predominant. Overexpression and depletion experiments show that Zfp206 promotes formation of undifferentiated ES cell clones, and positively regulates abundance of a very small set of transcripts whose expression is also specific to ES cells and the two- to four-cell stages of preimplantation embryos. This set includes members of the Zscan4, Thoc4, Tcstv1 and eIF-1A gene families, none of which have been functionally characterized in vivo but whose members include apparent transcription factors, RNA-binding proteins and translation factors. Together, these data indicate that Zfp206 is a regulator of ES cell differentiation that controls a set of genes expressed very early in development, most of which themselves appear to be regulators

Current usage by a DC motor to vary ratio in an electro-mechanical continuously variable transmission

In a typical continuously variable transmission (CVT) for automotive, engine torque is transmitted from the primary pulley (connected to the vehicle's engine) to the secondary pulley (connected to the wheels) through a metal pushing V-belt. The CVT ratio (rCVT ) is defined as the pitch radius of the belt on the secondary pulley divided by the pitch radius on the primary pulley. Conventionally, rCVT is varied using hydraulic pressure generated by an oil pump which is powered by the engine. A continuous hydraulic pressure is required to maintain high clamping force applied on the belt so that sufficient traction between the belt and the pulleys can always be provided. This requirement, unfortunately, causes significant power losses in the CVT and to address this, the idea of electro-mechanical CVT (EM CVT) is proposed. In an EM CVT, rCVT is varied using a power screw mechanism and a DC motor while the desired ratio and the belt's clamping force is maintained using the thread of the power screw mechanism, consequently eliminating the aforementioned issue. This paper describes the process of measuring the current used by a DC motor to vary rCVT in an EM CVT. The results show that the current usage is higher during upshifting from rCVT of 1.95 to 1.43 (about 45 A) as compared to downshifting from 1.43 to 1.95 (about 23 A). This is due to the application of disc springs in the secondary pulley that reduces the required motor torque for downshifting. The results also prove that no current is consumed by the motor during a constant rCVT . In conclusion, the motor's current usage has been successfully measured and the results can be used for a future development of the EM CVT's battery system

THE DEAD-END ELIMINATION THEOREM AND ITS USE IN PROTEIN SIDE-CHAIN POSITIONING

THE prediction of a protein's tertiary structure is still a considerable problem because the huge amount of possible conformational space' makes it computationally difficult. With regard to side-chain modelling, a solution has been attempted by the grouping of side-chain conformations into representative sets of rotamers 2-5. Nonetheless, an exhaustive combinatorial search is still limited to carefully identified packing units 5,6 containing a limited number of residues. For larger systems other strategies had to be developed, such as the Monte Carlo Procedure 6,7 and the genetic algorithm and clustering approach 8. Here we present a theorem, referred to as the 'dead-end elimination' theorem, which imposes a suitable condition to identify rotamers that cannot be members of the global minimum energy conformation. Application of this theorem effectively controls the computational explosion of the rotamer combinatorial problem, thereby allowing the determination of the global minimum energy conformation of a large collection of side chains

Use of loan loss provisions for capital, earnings management and signalling by Australian banks

This study examines whether and to what extent Australian banks use loan loss provisions (LLPs) for capital, earnings management and signalling. We examine if there were changes in the use of LLPs as a result of the implementation of banking regulations consistent with the Basel Accord of 1988, which made loan loss reserves no longer part of Tier I capital in the numerator of the capital adequacy ratio. We find some evidence to indicate that Australian banks use LLPs for capital management, but we find no evidence of a change in this behaviour after the implementation of the Basel Accord. Our results indicate that banks in Australia use LLPs to manage earnings. Furthermore, listed commercial banks engage more aggressively in earnings management using LLPs than unlisted commercial banks. We also find that earnings management behaviour is more pronounced in the post-Basel period. Overall, we find a significant understating of LLPs in the post-Basel period relative to the pre-Basel period. This indicates that reported earnings might not reflect the true economic reality underlying those numbers. Finally, Australian banks do not appear to use LLPs for signalling future intentions of higher earnings to investors. Copyright (c) The Authors Journal compilation (c) 2007 AFAANZ.