Spectroscopy of reflection-asymmetric nuclei with relativistic energy density functionals

Quadrupole and octupole deformation energy surfaces, low-energy excitation spectra and transition rates in fourteen isotopic chains: Xe, Ba, Ce, Nd, Sm, Gd, Rn, Ra, Th, U, Pu, Cm, Cf, and Fm, are systematically analyzed using a theoretical framework based on a quadrupole-octupole collective Hamiltonian (QOCH), with parameters determined by constrained reflection-asymmetric and axially-symmetric relativistic mean-field calculations. The microscopic QOCH model based on the PC-PK1 energy density functional and $\delta$-interaction pairing is shown to accurately describe the empirical trend of low-energy quadrupole and octupole collective states, and predicted spectroscopic properties are consistent with recent microscopic calculations based on both relativistic and non-relativistic energy density functionals. Low-energy negative-parity bands, average octupole deformations, and transition rates show evidence for octupole collectivity in both mass regions, for which a microscopic mechanism is discussed in terms of evolution of single-nucleon orbitals with deformation.Comment: 36 pages, 21 figures, Accepted for Publication in Physical Review

Inhomogeneous crystal grain formation in DPPC-DSPC based thermosensitive liposomes determines content release kinetics

Thermosensitive liposomes (TSL) receive attention due to their rapid externally controlled drug release at transition temperature in combination with hyperthermia. This rapid release feature of TSL occurs when the liposome membrane is going through a phase change which results in numerous interfaces, at so-called crystal grain boundaries. Based on experience with TSLs, our group found that thermosensitive liposomes formulated by binary compositions of DPPC and DSPC at proper ratios are able to exhibit rapid release without incorporation of release-promoting components. The aim of this study was to understand the mechanism of rapid release from bi-component DPPC-DSPC based TSL. Based on the investigation of a series of TSLs formulated by different DPPC-DSPC ratios, and through the analysis of binary-phase diagrams of DPPC-DSPC TSLs, we conclude that inhomogeneous crystal grains are formed in bi-component TSL membranes rather than mono-component, thereby facilitating content release. The resulting inhomogeneous membrane pattern is affected by DPPC/DSPC ratio, i.e. this determines the number of interfaces between solid and liquid phases at transition temperature, which can be diminished by addition of cholesterol. At appropriate DPPC/DSPC ratio, substantive solid/liquid interfaces can be generated not only between membrane domains but also between crystal grains in each domain of the liposome membranes, therefore improving content release from the TSL at transition temperatures

Understanding and improving thermosensitive smart drug delivery systems

This thesis aims to describe the use of DPPC-DSPC based thermosensitive liposome in combination with local mild hyperthermia to improve better chemotherapy efficacy from 2 parts: 1) what is the proper drug to be encapsulated in TSL, 2) what is the mechanism of our TSL rapid release and how to reach optimal release formulatio

A direct urea fuel cell - power from fertiliser and waste

For the first time, a working direct urea and direct urine fuel cell has been developed to generate electricity directly from urea or urine

Valence band offset of InN/AlN heterojunctions measured by X-ray photoelectron spectroscopy

The valence band offset of wurtzite-InN/AlN (0001) heterojunctions is determined by x-ray photoelectron spectroscopy to be 1.52±0.17 eV. Together with the resulting conduction band offset of 4.0±0.2 eV, a type-I heterojunction forms between InN and AlN in the straddling arrangement

Geometrical structure effect on localization length of carbon nanotubes

The localization length and density of states of carbon nanotubes are evaluated within the tight-binding approximation. By comparison with the corresponding results for the square lattice tubes, it is found that the hexagonal structure affects strongly the behaviors of the density of states and localization lengths of carbon nanotubes.Comment: 7 pages, 4 figures, revised version to appear in Chin. Phys. Lett. The title is changed. Some arguments are adde

A microcarrier-based spheroid 3D invasion assay to monitor dynamic cell movement in extracellular matrix

Background: Cell invasion through extracellular matrix (ECM) is a critical step in tumor metastasis. To study cell invasion in vitro, the internal microenvironment can be simulated via the application of 3D models. Results: This study presents a method for 3D invasion examination using microcarrier-based spheroids. Cell invasiveness can be evaluated by quantifying cell dispersion in matrices or tracking cell movement through time-lapse imaging. It allows measuring of cell invasion and monitoring of dynamic cell behavior in three dimensions. Here we show different invasive capacities of several cell types using this method. The content and concentration of matrices can influence cell invasion, which should be optimized before large scale experiments. We also introduce further analysis methods of this 3D invasion assay, including manual measurements and homemade semi-automatic quantification. Finally, our results indicate that the position of spheroids in a matrix has a strong impact on cell moving paths, which may be easily overlooked by researchers and may generate false invasion results. Conclusions: In all, the microcarrier-based spheroids 3D model allows exploration of adherent cell invasion in a fast and highly reproducible way, and provides informative results on dynamic cell behavior in vitro