Comment on "Can one predict DNA Transcription Start Sites by Studying Bubbles?"

Comment on T.S. van Erp, S. Cuesta-Lopez, J.-G. Hagmann, and M. Peyrard, Phys. Rev. Lett. 95, 218104 (2005) [arXiv: physics/0508094]

Healing Length and Bubble Formation in DNA

We have recently suggested that the probability for the formation of thermally activated DNA bubbles is, to a very good approximation, proportional to the number of soft AT pairs over a length L(n) that depend on the size $n$ of the bubble and on the temperature of the DNA. Here we clarify the physical interpretation of this length by relating it to the (healing) length that is required for the effect of a base-pair defect to become neligible. This provides a simple criteria to calculate L(n) for bubbles of arbitrary size and for any temperature of the DNA. We verify our findings by exact calculations of the equilibrium statistical properties of the Peyrard-Bishop-Dauxois model. Our method permits calculations of equilibrium thermal openings with several order of magnitude less numerical expense as compared with direct evaluations

CROSS-CULTURAL TRANSFER OF GLOBALLY INITIATED HEALTH PROMOTION POLICIES

This paper refers to the issue of cross-cultural transfer of globally initiated health promotion policies. The purpose of the study is to explore the possibilities of cross-cultural transfer looking at the international language of health promotion and to assess its applicability in terms of transfer to Bulgaria. It also aims to identify aspects of cross-cultural policy validity, consideration of which might assist the process of health promotion global policy transfer. The Walt model for health policy analysis was used as a basic analytical framework. The Hofstede model of national cultures was applied as a guiding tool to assess the cultural constraints and possibilities for cross-national policy transfer. The analysis revealed major difficulties of global health promotion policies transfer to the Bulgarian realities. Ideas were advanced about the need for global policy language interpretation and adaptation to develop a better fit for the purpose of specific locations. The results can be drawn up to set an agenda for further essential work on the pragmatic issues of how to modify the global policy items of health promotion and develop an interpretation that is in line with the realities of the Bulgarian life

Assessment of the Subjective Visual Dysfunction of Patients With Multiple Sclerosis Using Specialized Questionnaires

Recently, the questions of the limited opportunities for measurement of the subjective and often subclinical visual dysfunction are very topical. NEI-VFQ, the questionnaire of the National Eye Institute in the USA and VFQ-25, its short version (25-item Vision Function Questionnaire) are validated for visual-specific assessment of the quality of life of multiple sclerosis (MS) patients. MSVQ-7, a specific 7-item MS Vision Questionnaire is proposed, too. The authors used the VFQ-25 translated into Bulgarian, the MSVQ-7 and their correlation with the binocular visual acuity. These questionnaires were administered to 108 MS patients without history of optic neuritis and after optic neuritis as well registered in the MS Centre in Varna and to 30 healthy subjects. There was a statistically significant difference (p<0,0001) between MS patients and controls in all sub-scales and in the overall results from VFQ-25. The analysis of MSVQ-7 showed a statistically significant difference between the answers of question Nos 1, 2, 3 and 5  p<0,001 to p=0,015). The correlation of the results from VFQ-25 and the binocular visual acuity was moderate (Spearman's r=0,6;  <0,01). The application of questionnaires for assessment of visual function may contribute to the identification of less known and sought subclinical visual dysfunctions that appear in normal visual acuity. Our data confirm the possible usage of VFQ-25 and MSVQ-7 for effective measurement of the subjective visual deficit in MS diagnosis

DNA Breathing Dynamics in the Presence of a Terahertz Field

We consider the influence of a terahertz field on the breathing dynamics of double-stranded DNA. We model the spontaneous formation of spatially localized openings of a damped and driven DNA chain, and find that linear instabilities lead to dynamic dimerization, while true local strand separations require a threshold amplitude mechanism. Based on our results we argue that a specific terahertz radiation exposure may significantly affect the natural dynamics of DNA, and thereby influence intricate molecular processes involved in gene expression and DNA replication

Lengthscales and Cooperativity in DNA Bubble Formation

It appears that thermally activated DNA bubbles of different sizes play central roles in important genetic processes. Here we show that the probability for the formation of such bubbles is regulated by the number of soft AT pairs in specific regions with lengths which at physiological temperatures are of the order of (but not equal to) the size of the bubble. The analysis is based on the Peyrard- Bishop-Dauxois model, whose equilibrium statistical properties have been accurately calculated here with a transfer integral approach

Structurally specific thermal fluctuations identify functional sites for DNA transcription

We report results showing that thermally-induced openings of double stranded DNA coincide with the location of functionally relevant sites for transcription. Investigating both viral and bacterial DNA gene promoter segments, we found that the most probable opening occurs at the transcription start site. Minor openings appear to be related to other regulatory sites. Our results suggest that coherent thermal fluctuations play an important role in the initiation of transcription. Essential elements of the dynamics, in addition to sequence specificity, are nonlinearity and entropy, provided by local base-pair constraints

Mathematical simulation of water and methanol segregation processes at field preparation of gas condensate

Calculation modulus for water and methanol segregation processes from gas condensate has been developed. Applying the developed technological system the influence of process variables on segregation processes of water and methanol is studied. Modes of operation of liquid separators at which the most efficient segregation of water-methanol solution from unstable condensate occurs are recommende

Dynamics of water separation in destruction of water-in-oil emulsions

The dynamics of drop formation and settling processes in breaking water-in-oil emulsions of the West Siberian oil fields was experimentally studied. The investigation results of drop formation in the water-in-oil emulsions were presented. The residual water content in oil was determined after the settling process at the varied initial water content, temperature, and hydrodynamic conditions of emulsion formation