A two-layer approach to the coupled coherent states method

In this paper a two-layer scheme is outlined for the coupled coherent states (CCS) method, dubbed two-layer CCS (2L-CCS). The theoretical framework is motivated by that of the multiconfigurational Ehrenfest (MCE) method, where different dynamical descriptions are used for different subsystems of a quantum mechanical system. This leads to a flexible representation of the wavefunction, making the method particularly suited to the study of composite systems. It was tested on a 20-dimensional asymmetric system-bath tunnelling problem, with results compared to a benchmark calculation, as well as existing CCS, MP/SOFT and CI expansion methods. The two-layer method was found to lead to improved short and long term propagation over standard CCS, alongside improved numerical efficiency and parallel scalability. These promising results provide impetus for future development of the method for on-the-fly direct dynamics calculations

Annual solar UV exposure and biological effective dose rates on the Martian surface

The ultraviolet (UV) environment of Mars has been investigated to gain an understanding of the variation of exposure throughout a Martian year, and link this flux to biological effects and possible survival of organisms at the Martian surface. To gain an idea of how the solar UV radiation varies between different regions, including planned landing sites of two future Mars surface missions, we modelled the total solar UV surface flux throughout one Martian year for two different dust scenarios. To understand the degree of solar UV stress on micro-organisms and/or molecules essential for life on the surface of Mars, we also calculated the biologically effective dose (BED) for T7 and Uracil in relevant wavelength regions at the Martian surface as a function of season and latitude, and discuss the biological survival rates in the presence of Martian solar UV radiation. High T7/Uracil BED ratios indicate that even at high latitudes where the UV flux is significantly reduced, the radiation environment is still hostile for life due to the persisting UV-C component of the flux

Exploring young Australians’ understanding of sustainable and healthy diets: a qualitative study

Objective: This qualitative study aimed to explore young Australians’ perspectives, motivators and current practices in achieving a sustainable and healthy diet. Design: Semi-structured online interviews were conducted with young Australians. Interviews were audio-recorded using the online Zoom platform, transcribed and analysed using a deductive analysis method by applying the Theoretical Domains Framework and inductive thematic data analysis. Setting: Young Australians recruited via social media platforms, noticeboard announcements and flyers. Subjects: Twenty-two Australians aged 18 to 25 years. Results: The majority of participants were aware of some aspects of a sustainable and healthy diet and indicated the need to reduce meat intake, increase intake of plant-based foods, reduce food wastage and packaging and reduce food miles. Young adults were motivated to adopt more sustainable dietary practices but reported that individual and environmental factors such as low food literacy, limited food preparation and cooking skills, lack of availability and accessibility of environmentally friendly food options and costs associated with sustainable and healthy diets hindered their ability to do so. Conclusions: Given the barriers faced by many of our participants, there is a need for interventions aimed at improving food literacy and food preparation and cooking skills as well as those that create food environments that make it easy to select sustainable and healthy diets. Future research is needed for longitudinal larger scale quantitative studies to confirm our qualitative findings. In addition, the development and evaluation of individual and micro-environmental-based interventions promote sustainable and healthy diets more comprehensively

ELLIPSOMETRIC STUDIES OF BIOLOGICAL MACROMOLECULES

L'éllipsométrie a été utilisée pour étudier les propriétés d'adhésion de collagène et fibrinogène sur une surface métallique (Cr). L'épaisseur et l'indice de réfraction des couches obtenues ont été étudiés en fonction du temps d'incubation et de la concentration moléculaire. La même méthode a été appliquée pour étudier aussi l'adhésion du bactériophage T7.Adsorption properties of collagen and fibrinogen on Cr metal surface has been studied by ellipsometry. The thickness and refractive index of the thin films have been determined in function of the incubation time and solute concentration. The same method has been also applied to investigate the adsorption of T7 bacteriophage

Influence of phage proteins on formation of specific UV DNA photoproducts in phage T7

Phage T7 can be used as a biological UV dosimeter. Its reading is proportional to the inactivation rate expressed in HT7 units. To understand the influence of phage proteins on the formation of DNA UV photoproducts, cyclobutane pyrimidine dimers (CPD) and (6-4)photoproducts ((6-4)PD) were determined in T7 DNA exposed to UV radiation under different conditions: intraphage T7 DNA, isolated T7 DNA and heated phage. To investigate the effects of various wavelengths, seven different UV sources have been used. The CPD and (6-4)PD were determined by lesion-specific antibodies in an immunodotblot assay. Both photoproducts were HT7 dose-dependently produced in all three objects by every irradiation source in the biologically relevant UV dose range (1-10 HT7). The CPD to (6-4)PD ratios increased with the increasing effective wavelength of the irradiation source and were similar in intraphage T7 DNA, isolated DNA and heated phage with all irradiation sources. However, a significant decrease in the yield of both photoproducts was detected in isolated T7 DNA and in heated phage compared to intraphage DNA, the decrease was dependent on the irradiation source. Both photoproducts were affected the same way in isolated T7 DNA and heated phage, respectively. The yield of CPD and (6-4)PD was similar in B, C-like and A conformational states of isolated T7 DNA, indicating that the conformational switch in the DNA is not the decisive factor in photoproduct formation. The most likely explanation for modulation of photoproduct frequency in intraphage T7 DNA is that the presence of bound phage proteins induces an alteration in DNA structure that can result in an increased rate of dimerization and (6-4)PD production of adjacent bases in intraphage T7 DNA