Water network dynamics at the critical moment of a peptide's ß-turn formation:a molecular dynamics study

All-atom molecular dynamics simulations for a single molecule of Leu-Enkephalin in aqueous solution have been used to study the role of the water network during the formation of ß-turns. We give a detailed account of the intramolecular hydrogen bonding, the water-peptide hydrogen bonding, and the orientation and residence times of water molecules focusing on the short critical periods of transition to the stable ß-turns. These studies suggest that, when intramolecular hydrogen bonding between the first and fourth residue of the ß-turn is not present, the disruption of the water network and the establishment of water bridges constitute decisive factors in the formation and stability of the ß-turn. Finally, we provide possible explanations and mechanisms for the formations of different kinds of ß-turns.

Refractive index sensitivity characteristics near the dispersion turning point of the multimode microfiber-based Mach–Zehnder interferometer

The turning point of the refractive index (RI) sensitivity based on the multimode microfiber (MMMF) in-line Mach–Zehnder interferometer (MZI) is observed. By tracking the resonant wavelength shift of the MZI generated between the HE11 and HE12 modes in the MMMF, the surrounding RI (SRI) could be detected. Theoretical analysis demonstrates that the RI sensitivity will reach ±∞ on either side of the turning point due to the group effective RI difference (퐺) approaching zero. Significantly, the positive sensitivity exists in a very wide fiber diameter range, while the negative sensitivity can be achieved in a narrow diameter range of only 0.3 μm. Meanwhile, the experimental sensitivities and variation trend at different diameters exhibit high consistency with the theoretical results. High RI sensitivity of 10777.8 nm/RIU (RI unit) at the fiber diameter of 4.6 μm and the RI around 1.3334 is realized. The discovery of the sensitivity turning points has great significance on trace detection due to the possibility of ultrahigh RI sensitivity.

Regulating audit beyond the crisis:a critical discussion of the EU green paper

With the European Commission making global leadership claims in the field of audit regulation, the content of its 2010 Green Paper on ‘Audit Policy: Lessons from the Crisis’ warrants careful scrutiny. Important issues raised in the Green Paper include regulatory oversight, competition in the audit market, the dangers of having very few firms with the capacity to audit global transnational corporations, professional judgement, innovative audit practices and, last but not least, social responsibility. This article analyses the principal perspectives and assumptions underpinning the construction of the Green Paper. The aims are threefold: to enhance understanding of the contemporary regulatory mindset of the European Commission, contribute to policy debate and inspire future research.

The value of risk reporting:a critical analysis of value-at-risk disclosures in the banking sector

This paper critically reviews the evolution of financial reporting in the banking sector with specific reference to the reporting of market risk and the growing use of the measure known as Value at Risk (VaR). The paper investigates the process by which VaR became 'institutionalised'. The analysis highlights a number of inherent limitations of VaR as a risk measure and questions the usefulness of published VaR disclosures, concluding that risk 'disclosure' might be more apparent than real. It also looks at some of the implications for risk reporting practice and the accounting profession more generally.