Shijie Lv

W@Si12 cluster as a potential sensor for CO and NO detection

The adsorption of several common gas molecules on the W@Si12 cluster was investigated using density functional theory calculations in terms of geometric, energetic, and electronic properties to exploit its potential applications as gas sensors. It is found that the CO and NO molecules can be chemisorbed on the W@Si12 cluster with exothermic adsorption energy ( to ), and can lead to finite charge transfer. The electronic properties of the W@Si12 cluster present dramatic changes after the adsorption of the CO and NO molecules, especially its electric conductivity. However, the HCN, CO2, N2, O2, and H2O molecules are weakly physisorbed on the cluster, and do not induce significant change in electronic properties of the W@Si12 cluster. Thus, the W@Si12 cluster is expected to be a promising gas sensor for CO and NO detection.

C54Si6 heterofullerene as a potential gas sensor for CO, NO, and HCN detection

The adsorption of CO, NO, and HCN molecules on the C54Si6 heterofullerene is investigated on the basis of density functional theory calculations to exploit its potential applications as a gas sensor. The C54Si6 heterofullerene has two highly stable isomers (named isomer-1 and isomer-2). We find that the toxic CO, NO, and HCN molecules are chemically adsorbed on isomer-1 with moderate adsorption energies and apparent charge transfer. The electronic properties of isomer-1 are significantly influenced by the CO, NO, and HCN adsorption, especially its electric conductivity. The recovery time of the isomer-1 sensor for CO, NO, and HCN at room temperature is estimated to be short due to the medium (optimal) adsorption energies, indicating that isomer-1 (i.e. the most stable configuration) of C54Si6 heterofullerene should be a good CO, NO, and HCN sensor. Similar analysis indicates that the isomer-2 of C54Si6 heterofullerene is a potential efficient gas sensor for NO detection.

Ordered RTiO2@ATiO2 architecture for dye-sensitized solar cell applications

Herein, we report a green and convenient method to prepare a compact layer for better construction of hierarchical TiO2 architectures to serve as photoanodes, in which one-dimensional (1D) rutile TiO2 (RTiO2) arrays are grown hydrothermally on a compact layer for fast electron transport, and branched anatase TiO2 (ATiO2) particles are deposited orderly on RTiO2 backbones for high efficiency dye harvesting. Characteristic tests indicate that the 1D RTiO2 arrays are tetragonal in shape with a square top surface, whereas the branched ATiO2 particles are nanoconic in shape with exposed {001} facets. As a result, the RTiO2@ATiO2 photoanode, sensitized by the N719 dye, harvests a solar energy conversion efficiency of 5.68%, which is nearly 3 times higher than that found in the RTiO2 array-based dye-sensitized solar cell (DSSC), which demonstrates that the RTiO2 nanorods decorated by ATiO2 nanocones are helpful in enhancing the solar energy conversion efficiency.

Density functional studies of small silicon clusters adsorbed on graphene

The structural and electronic properties of small Sin clusters (n = 1–6, 10) adsorbed on graphene are studied by use of density functional theory within periodic boundary conditions. Our results show that the structural properties of the deposited Sin clusters and graphene are weakly affected by their interaction. The adsorption energy difference of different adsorption sites for the same size Si cluster on graphene is very small, indicating the Sin-cluster–graphene system will be obtained easily. There is a little charge transfer from Sin clusters to graphene when the cluster size is larger. The adsorption of Sin clusters will be an effective method to open of an energy gap for graphene, which is useful for the applications of graphene to electrical and optical devices. Especially, the adsorption of Sin cluster with large size (n ≥ 5) would have a band gap with a constant energy value.

Dihydroartemisinin induces apoptosis and downregulates glucose metabolism in JF-305 pancreatic cancer cells

Cancer cell promotion of glycolysis provides a promising therapeutic target for cancer treatment. Dihydroartemisinin (DHA) displays cytotoxicity to multiple human tumor cells. However, its effects on pancreatic cancer cells are not well studied. The objective of this study was to investigate the effect of DHA on glucose metabolism and cell viability in JF-305 pancreatic cancer cells. To achieve these goals, cell viability was measured with MTT assay, and the occurrence of apoptosis was detected. Glucose uptake, lactate production, and ATP content were measured. Western blotting was used for the detection of apoptosis-related protein expression. The result showed that DHA caused significant reduction in JF-305 cell viability, arrested the cell phase in G2/M, induced apoptosis, and decreased the mitochondrial membrane potential and accumulated ROS. DHA also inhibited glucose uptake, lactate generation, and ATP production. Western blotting showed that treatment with DHA increased the activity of caspase-9 and caspase-3, downregulated Bcl-2 expression, and upregulated the expression levels of Bax and Cyto C. Meanwhile, DHA downregulated the Akt/mTOR signaling pathway and inhibited glucose transporter 1 expression. Our data suggest that DHA treatment increased the apoptosis of JF-305 pancreatic cancer cells, and the effect of apoptosis may be associated with the inhibition of glycolysis.

Adsorption of gas molecules on Gd@Aun (n = 14, 15) clusters and their implication for molecule sensors

First-principles calculations are performed to study the adsorption of CO, NO, NO2, O2, CO2, N2, and H2O molecules on Gd@Aun (n = 14, 15) clusters. The adsorption geometries, adsorption energies, charge transfer, and electronic properties are obtained. We find that the toxic molecules (CO, NO, and NO2) are chemically adsorbed on the Gd@Aun (n = 14, 15) clusters with strong binding, and this can lead to finite charge transfer, while other common molecules (O2, CO2, N2, and H2O) are physisorbed on the Gd@Aun (n = 14, 15) clusters, expect for O2 molecules on the Gd@Au14 cluster. The electronic properties of the Gd@Aun (n = 14, 15) clusters are significantly influenced by NO and NO2 adsorption, especially their electric conductivity. Furthermore, for the Gd@Au15 cluster, it is found that the adsorption energy (Eads) of −0.498 eV for NO and −0.725 eV for NO2 corresponds to recovery times of about 7 × 10−12 and 11.8 s, respectively, indicating that the Gd@Au15 cluster should be a good NO and NO2 sensor with quick response and short recovery time. However, the very strong adsorption of NO and NO2 on the Gd@Au14 cluster (Eads ≥ 1.00 eV) makes desorption difficult. Therefore, the Gd@Au15 cluster can be expected to be an excellent gas sensor for NO and NO2 detection.

The H60Si6C54 heterofullerene as high-capacity hydrogen storage medium

With the great success in Si atoms doped C60 fullerene and the well-established methods for synthesis of hydrogenated carbon fullerenes, this leads naturally to wonder whether Si-doped fullerenes are possible for special applications such as hydrogen storage. Here by using first-principles calculations, we design a novel high-capacity hydrogen storage material, H60Si6C54 heterofullerene, and confirm its geometric stability. It is found that the H60Si6C54 heterofullerene has a large HOMO-LUMO gap and a high symmetry, indicating it is high chemically stable. Further, our finite temperature simulations indicate that the H60Si6C54 heterofullerene is thermally stable at 300 K. H2 molecules would enter into the cage from the Si-hexagon ring because of lower energy barrier. Through our calculation, a maximum of 21 H2 molecules can be stored inside the H60Si6C54 cage in molecular form, leading to a gravimetric density of 11.11 wt% for 21H2@H60Si6C54 system, which suggests that the hydrogenated Si6C54 heterofuller...