Evolutionary diversity and developmental regulation of X-chromosome inactivation

X-chromosome inactivation (XCI) results in the transcriptional silencing of one X-chromosome in females to attain gene dosage parity between XX female and XY male mammals. Mammals appear to have developed rather diverse strategies to initiate XCI in early development. In placental mammals XCI depends on the regulatory noncoding RNA X-inactive specific transcript (Xist), which is absent in marsupials and monotremes. Surprisingly, even placental mammals show differences in the initiation of XCI in terms of Xist regulation and the timing to acquire dosage compensation. Despite this, all placental mammals achieve chromosome-wide gene silencing at some point in development, and this is maintained by epigenetic marks such as chromatin modifications and DNA methylation. In this review, we will summarise recent findings concerning the events that occur downstream of Xist RNA coating of the inactive X-chromosome (Xi) to ensure its heterochromatinization and the maintenance of the inactive state in the mouse and highlight similarities and differences between mammals

Specific patterns of histone marks accompany X chromosome inactivation in a marsupial

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Determination of bismuth in serum and urine by direct injection nebulization inductively coupled plasma mass spectrometry

A sensitive method for the determination of Bi by direct injection nebulization inductively coupled plasma mass spectrometry (DIN-ICP-MS) in biological fluids is described. The detection limit for Bi is 9.7 ng 1-1 (ca. 46 pmol dm-3) with DIN compared with 17 ng 1-1 (ca. 81 pmol dm-3) with conventional pneumatic nebulization (PN). The absolute amount detectable by DIN-ICP-MS is about two orders of magnitude lower for DIN compared with PN (0.019 and 1.70 pg, respectively). Sample wash-out times were greatly reduced using DIN owing to minimization of the memory effect for Bi. Using T1 as an internal standard, good calibrations were obtained for Bi standards in 0.14 mol dm-3 nitric acid, serum and urine with comparable linearity between the matrices, and these were used for the determination of Bi in serum and urine samples from animals dosed with the antiulcer compound RBC (ranitidine bismuth citrate). This method is potentially useful in studies of the metabolism and biodistribution of Bi-containing drugs.link_to_subscribed_fulltex

Determination of bismuth in serum and urine by direct injection nebulization inductively coupled plasma mass spectrometry

A sensitive method for the determination of Bi by direct injection nebulization inductively coupled plasma mass spectrometry (DIN-ICP-MS) in biological fluids is described. The detection limit for Bi is 9.7 ng 1-1 (ca. 46 pmol dm-3) with DIN compared with 17 ng 1-1 (ca. 81 pmol dm-3) with conventional pneumatic nebulization (PN). The absolute amount detectable by DIN-ICP-MS is about two orders of magnitude lower for DIN compared with PN (0.019 and 1.70 pg, respectively). Sample wash-out times were greatly reduced using DIN owing to minimization of the memory effect for Bi. Using T1 as an internal standard, good calibrations were obtained for Bi standards in 0.14 mol dm-3 nitric acid, serum and urine with comparable linearity between the matrices, and these were used for the determination of Bi in serum and urine samples from animals dosed with the antiulcer compound RBC (ranitidine bismuth citrate). This method is potentially useful in studies of the metabolism and biodistribution of Bi-containing drugs.link_to_subscribed_fulltex

China's New Generation Trade Agreements : Importing Rules to Lock in Domestic Reform?

Since the beginning of the 21st century we have witnessed a proliferation of Preferential Trade Agreements (PTAs) in Asia Pacific. China has been at the forefront of this development. Initially, China's PTAs were very shallow and mainly aimed at building friendly relationships with developing countries. However, over time, China has started to negotiate deeper PTAs with developing and developed countries alike. This notable shift has thus far been understood to result from four broad motivations: China's desire to access key export markets; the facilitation of regional production networks; to address resource security concerns; and/or to further geostrategic interests and political influence. We propose that these motives are not sufficient to fully account for China's new generation trade agreements. We suggest that China is increasing its integration into the world economy to push for domestic marketization and reform by credibly committing to trade liberalization through PTAs. Deep and comprehensive PTAs oblige a country to follow a set of rules that leave little leeway to violate the terms. In order to successfully implement and enforce PTA commitments, China has also gradually strengthened its regulatory state by investing in regulatory capacity and capability in the field of trade policy. We test the plausibility of our argument through an in‐depth analysis of the PTAs signed by China since 2000 and find evidence that China's PTAs are indeed in part driven by a desire to lock in domestic economic reform, which has gone hand in hand with a strengthening of its regulatory state