In this work, we propose a non-interacting model of Barrow holographic dark energy (BHDE) using Barrow entropy in a spatially flat FLRW Universe considering the IR cutoff as the Hubble horizon. We study the evolutionary history of important cosmological parameters, in particular, deceleration parameter, equation of state (EoS) parameter, the BHDE and matter density parameter, and also observe satisfactory behaviors in the BHDE model. The stability of the BHDE model has been examined by squared sound speed [Formula: see text]. In addition, to describe the accelerated expansion of the Universe, the correspondence of the BHDE model with the quintessence scalar field has been reconstructed.

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We have studied the separation of a double stranded DNA (dsDNA), which is driven by either the temperature or force. By monitoring the probability of opening of entire base pairs along the chain, we show that the opening of a dsDNA depends not only on the sequence but also on the constraints on the chain in the experimental setups. Our results clearly demonstrate that the force-induced melting of dsDNA, whose one of the ends is constrained, is significantly different from the thermal melting, when both ends are free.

AbstractsVarious e!ectronic indices calculated by the CNDO/S-CI method for uracil, 5-fluorouracil, thymine, and cytosine and the Woodward-Hoffmann rule applied to the photodimerization of these molecules lead us to the following conclusions: (i) decrease of the C5-C6 bond order consequent to excitation is generally correlated with the photodimerization reaction for all the biological pyrimidines; (ii) excited pyrimidine molecules may be nonplanar and the excitation would be delocalized over both the molecules which photodimerize; (iii) electrostatic interactions may play a significant role in the initial stages of the photodimerization reaction; (iv) singlet precursors to the stable triplet photodimers may exist; and (v) electron density does not, in general, increase in the C5-C6 bond in the excited state as compared to the ground state, contradicting the proposals of some earlier workers. Hybrid population densities and v-bond orders have been calculated for the first time for the molecules. Fluorine in 5-fluorouracil perturbs the hybrid populations as compared to those of uracil mainly in its vicinity.Des indices tlectroniques divers calculks par la mbthode CNDO/S-CI pour l'uracile, la 5 -fluorouracile, la thymine et la cytosine et la regle de Woodward-Hoffmann appliquee a la photodimerisation de ces molecules menent aux conclusions suivantes: (i) la reduction de I'ordre de la liaison C -C 6 suivant I'excitation est gineralement correlee a la reaction de photodimerisation pour toutes les pyrimidines biologiques. (ii) les molecules de pyrimidine excitees peuvent &tre nonplanes et I'excitation peut alors &tre delocaliste sur les deux molecules photodimerisees; (iii) les interactions electrostatiques peuvent jouer un r81e significatif dans les &tapes initiales de la reaction de photodimerisation; (iv) des prtcurseurs singulets aux photodimeres triplets peuvent exister; (v) la densite electronique en gtneral n'augmente pas dans la liaison C5-C6 dans I'etat excitt en comparaison avec I'etat fondamental, ce qui est contradictoire aux suggestions de certains chercheurs. Des densites de population hybrides et des ordres des liaisons u ont CtC calcules pour la premiere fois pour ces molecules. Le fluor dans la 5-fluorouracile perturbe les populations hybrides en comparaison avec celles de I'uracile du voisinage.Verschiedene mit der cNDo/s-cI-Methode berechnete Elektronenindizes fur Uracil, 5-fluorouracil, Thymin und Cytosin zusammen mit der auf die Photodimerisierung dieser Molekule angewandten Woodward-Hoffmann'schen Regel fiihren zu den folgenden Folgerungen: (i) die Abnahme der C5-C6-Bindungsordnung nach einer Anregung ist im allgemeinen mit der Photodimerisierungsreaktion fur alle biologischen Pyrimidinen korreliert; (ii) angeregte Pyrimidinmolekule konnen nicht-eben sein und die Anregung ware iiber beide photodimerisierte Molekule delokalisiert; (iii) elektrostatische Wechselwirkungen konnen eine bedeutsame Rolle in den Anfangsstufen der Photodimerisierungsreaktion spielen; (iv) Singulettvorlaufer zu den stabilen ...

We study the fluctuational dynamics of a tagged base-pair in double stranded DNA. We calculate the drift force which acts on the tagged base-pair using a potential model that describes interactions at base pairs level and use it to construct a Fokker-Planck equation.The calculated displacement autocorrelation function is found to be in very good agreement with the experimental result of Altan-Bonnet et. al. Phys. Rev. Lett. 90, 138101 (2003) over the entire time range of measurement. We calculate the most probable displacements which predominately contribute to the autocorrelation function and the half-time history of these displacements.