DFT Study on Two C_4N_(12)O_4 Isomers with Pagodane- and Isopagodane-like Structures

Geometries, energies, and vibrational frequencies for two C4N12O4 isomers with pagodane- and isopagodane-like structures have been calculated at the B3LYP/6-31G＊ level.Isomers 1 and 2 are of D2h and D2d symmetry, respectively. Heats of formation for the two C4N12O4 isomers have been estimated in this paper, indicating they would be reasonable candidates for high energy density materials.

相对论性电子的Compton散射

用单粒子理论研究了相对论性电子的Compton散射．当散射过程不改变光子运动方向时，存在n倍频效应，也存在光子频率及运动方向都不改变的散射过程．指出了一定条件下可以实现激光场对电子的有效加速．

Magnetovolume and chemical bonding effects of Ni atom in γ'-(Fe_1-xNi_x)_4N compounds

By X-ray diffraction and high pressure Mossbauer spectroscopy, the structure and the hyperfine parameters of Ni substituted γ-Fe4N were investigated. The results of X-ray diffraction indicate that single phase γ’-(Fe1-xNix)4N compounds can be prepared in the composition range of 0≤x≤0.6, and with the increase of Ni content the lattice parameter is fit for the relationship a0(x) = 3.790 5-0.021 57x-0.031 67x2. By high pressure Mossbauer spectra, effects of magnetovolume and chemical bonding of Ni atom on hyperfine magnetic field and isomer shift of iron were distinguished for the first time, and their composition dependences for different lattice sites were studied simultaneously. It is found that the magnetovolume and chemical bonding have different influences on the properties of γ’-(Fe1-xNix)4N, and the latter one plays a key role in the property changes of γ-(Fe1-xNix)4N.

Heterofullerenes C_(48)N_(12) and C_(48)B_(12) with Rare T_h Symmetry: a DFT Study

The molecule with Th symmetry is rare. Two C60-1ike molecules C48N12 and C48B12 with rare Th symmetry have been reported here, which is an approach to seek for the molecule with rare Th symmetry. Their structural, electronic, vibrational, NMR, and thermodynamic properties have been calculated at the B3LYP/6-31G（d） level of theory. Vibrational modes have been assigned according to their symmetry. They all have 73 independent vibrational modes： 22 IR-active modes with Tu symmetry and 37 Raman-active modes with Ag, Eg and Tg symmetry, respectively. The heats of formation have been calculated using isodesmic reactions, and the values of C48N12 and C48B12 are 3812.0 and 3423.8 kJ mo1-1, respectively. According to the estimated band gaps for their fcc solid, they are all semiconducting materials, like C60, especially C48B12-based fcc solid.

Epigenetic Enabled Normal Human Cells, Lead to <i>First Cell</i>’s Unique Division System, Driving Tumorigenesis Evolution

Normal cells must become cancer-enabling before anything else occurs, according to latest literature. The goal in this mini-review is to demonstrate special tetraploidy in the enabling process. This we have shown from genomic damage, DDR (DNA Damage Response) activity with skip of mitosis leading to diploid G2 cells at the G1 border in need of chromatin repair for continued cell cycling to the special tetraploid division system. In several studies specific methylation transferase genes were activated in normal human cells in tissue fields, containing different cell growth stages of the cancerous process. Histology studies, in addition to molecular chemistry for identification of oncogenic mutational change, were a welcome change (see below). In a study on melanoma origin, DDR also showed arrested diploid cells regaining cycling from methylation transferase activity with causation of 2n melanocytes transforming to 4n melanoblasts, giving rise to epigenetic tumorigenesis enabled First Cells. Such First Cells were from Barrett’s esophagus shown to have inherited the unique division system from 4n diplochromosomal cells, first described in mouse ascites cancer cells (below). We discovered that the large nucleus prior to chromosomal division turned 90° relative to the cytoskeleton axis, and divided genome reductive to diploid, First Cells, in a perpendicular orientation to the surrounding normal cells they had originated from. This unique division system was herein shown to occur at metastasis stage, implying activity throughout the cancerous evolution. Another study showed 4-chromatid tetraploidy in development to B-cell lymphoma, and that such cancer cells also proliferated with participation of this unusual division system. Such participation has long been known from Bloom’s inherited syndrome with repair chiasmas between the four chromatids, also an in vitro observation by us. Our cytogenetic approach also revealed that they believed mitotic division in cancer cells is wrong because such cell divisions were found to be from an adaptation between amitosis and mitosis, called amitotic-mitosis. Amitosis means division without centrosomes, which has long been known from oral cancer cells, in that MOTCs (microtubule organizing center) were lacking centrioles. This observation calls for re-introduction of karyotype and cell division studies in cancer cell proliferation. It has high probability of contributing novel approaches to cancer control from screening of drugs against the amitotic-mitotic division apparatus.

Theoretical study on the hydrolysis mechanism of N,N-dimethyl-N′-(2′,3′-dideoxy-3′-thiacytidine)formamidine

The hydrolysis mechanisms of N,N-dimethyl-N′-(2′,3′-dideoxy-3′-thiacytidine)formamidine (FA-3TC) in the gas phase and in aqueous solution were studied by use of the density functional theory B3LYP/6-31+G(d, p) method. Two possible reaction pathways in the title reaction were considered. In one pathway water attacks the C=N double bond first (path A) while in the other water attacks the C—N single bond first (path B). The calculated results indicate that the first step in both pathways is the rate-limiting process and path A is more favorable than path B in the gas phase. The effect of solvent water on the title reaction was assessed at the B3LYP/6-31+G(d, p) level of theory based on the po-larizable continuum model (CPCM). In water the first mechanism (path A) is also favored.

相对论性电子与强场作用的非线性理论

研究了相刘沧性电子在强激光场中的非线性康普顿散射，进而导出散射光子频率的表达式．结果表明：当散射角为0时，电子仪仪充当了“耦合器”的作用，并存在n倍频效应．当散射角为π时，若电子和光子对撞，散射光子的频率随电子吸收光子数n的增大而增大，随激光场强度增强而减小；若光子追上电子而发生碰撞且散射光子被反弹时，可实现激光场对电子的有效加速．