Why the Orientational Mobility in Arginine and Lysine Spacers of Peptide Dendrimers Designed for Gene Delivery Is Different?

New peptide dendrimer with Lys-2Arg repeating units was recently studied experimentally by NMR (RSC Advances, 2019, 9, 18018) and tested as gene carrier successfully (Int. J. Mol. Sci., 2020, 21, 3138). The unusual slowing down of the orientational mobility of 2Arg spacers in this dendrimer was revealed. It has been suggested that this unexpected behavior is caused by the Arg-Arg pairing effect in water, which leads to entanglements between dendrimer branches. In this paper, we determine the reason for this slowing down using atomistic molecular dynamics simulation of this dendrimer. We present that the structural properties of Lys-2Arg dendrimer are close to those of the Lys-2Lys dendrimer at all temperatures (Polymers, 2020, 12, 1657). However, the orientational mobility of the H-H vector in CH2-N groups of 2Arg spacers in Lys-2Arg dendrimer is significantly slower than the mobility of the same vector in the Lys-2Lys dendrimer. This result is in agreement with the recent NMR experiments for the same systems. We revealed that this difference is not due to the arginine-arginine pairing, but is due to the semiflexibility effect associated with the different contour length from CH2-N group to the end of the side arginine or lysine segment in spacers.

Pairing Effect pada Isotop Cr dengan Menggunakan Uniform Fixed Potential Interaction

<p class="AbstrakIndonesia"><strong><em>Abstract:</em></strong><em> </em>Pairing is collective phenomenon caused by fermions as neutron and proton collected in nuclei, this phenomenon can be found in the formation of isotopes such as the Cr-isotopes. Pairing has an impact on the amount of nuclear binding energy. Like as social being uniquely, fermions will have a strong relationship when collected in nuclei isotopes. Their binding energy will increase when the nuclei have a paired of even-even number neutron or proton. One of the most powerful approaches in explaining the pairing effect is the Bardeen-Cooper-Srhrieffer approximation (BCS-Approximation), which is forms the basis of the theory superfluidity phenomenon in nucleiIn BCS-Approximation requires an interaction potential matrix that describes the neutron interactions between energy levels. We used uniform fixed potential energy 0.5 MeV, 0.1 MeV, and 0.01 MeV which is will be an option in this approach to calculate the total binding energy in Cr-isotopes.</p><p class="AbstrakIndonesia"><strong>Abstrak:</strong> Pairing merupakan fenomena keloktif dari beberapa fermion yang berkumpul, fenomena ini dapat ditemukan pada pembentukan isotop seperti isotop Cr. Pairing atau pasangan akan berdampak pada besar energi ikat inti atom, seperti halnya makhluk sosial yang akan meemliki hubungan yang kuat ketika berkumpul, isotop suatu nuklida juga akan mengalami peningkatan energi ikat ketika jumlah partikel semakin banyak dan berjumlah genap atau berpasangan. Salah satu pendekatan yang sangat powerfull dalam menjelaskan pairing effect tersebut adalah pedekatan Bardeen, Cooper, dan Schrieffer yang dikenal dengan BCS Approximation, yang menjadi dasar teori dari fenomena superfluidity. Penggunaan pendekatan ini memerlukan matriks potensial interaksi yang menggambarkan interaksi neutron antar level energi, penggunaan Uniform Fixed Potential Interaction yang bernilai 0.5 MeV, 0.1 MeV, dan 0.01 MeV menjadi salah satu pilihan dalam pendekatan ini untuk menghitung energi ikat total inti isotop Cr.</p>

Parity equilibration in nuclear level densities of 159–166Dy

Excitation-energy dependent parity ratios in the level densities of [Formula: see text] isotopes are calculated within a microscopic approach. Introducing a parity equilibration parameter, energy dependence of the transition from where a single parity dominates to a parity equilibrated state is compared among [Formula: see text] isotopes and its relation to the pairing effect is investigated. A correlation between the pair-breaking and the equilibration of parity distributions is observed for the considered isotopes.

2′-O-Methyl molecular beacon: a promising molecular tool that permits elimination of sticky-end pairing and improvement of detection sensitivity

A novel fluorescence sensor is reported based on the employment of an intriguing 2′-O-methyl molecular beacon (MB) and DNase I, the coupled use of which is responsible for both the elimination of the sticky-end pairing effect and signal amplification capability.

Moment of inertia of even–even proton-rich nuclei using a particle-number conserving approach in the isovector neutron–proton pairing case

An expression of the particle-number projected nuclear moment of inertia (MOI) has been established in the neutron–proton (np) isovector pairing case within the cranking model. It generalizes the one obtained in the like-particles pairing case. The formalism has been, as a first step, applied to the picket-fence model. As a second step, it has been applied to deformed even–even nuclei such as [Formula: see text] and of which the experimentally deduced values of the pairing gap parameters [Formula: see text], [Formula: see text], are known. The single-particle energies and eigenstates used are those of a deformed Woods–Saxon mean-field. It was shown, in both models, that the np pairing effect and the projection one are non-negligible. In realistic cases, it also appears that the np pairing effect strongly depends on [Formula: see text], whereas the projection effect is practically independent from the same quantity.