Asymmetric cancer-cell filopodium growth induced by electric-fields in a microfluidic culture chip

We combine a micro-fluidic electric-field cell-culture (MEC) chip with structured-illumination nano-profilometry (SINAP) to quantitatively study the variations of cancer cell filopodia under external direct-current electric field (dcEF) stimulations. Because the lateral resolution of SINAP is better than 150 nm in bright-field image modality, filopodia with diameters smaller than 200 nm can be observed clearly without fluorescent labeling. In the MEC chip, a homogeneous EF is generated inside the culture area that simulates the endogenous EF environment. With this MEC chip-SINAP system, we directly observe and quantify the biased growth of filopodia of lung cancer cells toward the cathode. The epidermal growth factor receptors around the cell edges are also redistributed to the cathodal side. These results suggest that cancer-cell filopodia respond to the changes in EFs in the microenvironment.     

Isolation and characterization of a newly identified type II restriction endonuclease from a local streptomyces sp. in Taiwan

Streptomyces chusanensis ZS-2, isolated from a soil sample in Chusan in Taiwan, was found to produce a new Type II restriction endonuclease. This restriction enzyme was designated as SchI. The purified enzyme was characterized as having a subunit mol wt of 28 kDa, and was apparently free from exonuclease activities. It cleaves the phosphodiester bond between the fourth C and the fifth G on the 5’-CCGCGG-3’ sequence of DNAs, leaving a 2-nucleotide protruding end at its 3’ site. This data suggests that SchI is an isoschizomer of SacII. In addition, based on the comparison between SchI and SacII regarding reaction parameters, it seems that SchI is a better choice of restriction enzyme for genetic analysis and mapping.     

Cubic planar hamiltonian graphs of various types

Let U be the set of cubic planar hamiltonian graphs, A the set of graphs G in U such that G-v is hamiltonian for any vertex v of G, B the set of graphs G in U such that G-e is hamiltonian for any edge e of G, and C the set of graphs G in U such that there is a hamiltonian path between any two different vertices of G. With the inclusion and/or exclusion of the sets A,B, and C, U is divided into eight subsets. In this paper, we prove that there is an infinite number of graphs in each of the eight subsets.     

Transmission Characteristics of 90° Bent Photonic Crystal Waveguides

There are several key factors that affect the transmission characteristics of the 90° (L-shaped) bent photonic crystal waveguides. The first factor is the direct coupling efficiency from the incident lights into the waveguides. The second one is the bandgap deviations of the photonic crystals. And the third factor is the optical reflections in the bent corners. In this article, we compare three types of L-shaped bent photonic crystal waveguides. One is the original type, which has an abrupt right-angle bend. Another is an improved 90° bend with a 45°-mirror. The other is an L-shaped bent photonic crystal waveguide with a 45°-transitional section. We investigate their respective frequency responses and observe the improvements in the total transmission efficiencies provided by the latter types.     

Influence diagnostic for censored regression models

This paper proposes a diagnostic measure to detect outliers either in the response variable or in the design space both for Schmee-Hahn estimator and Buckley-James estimator in censored regressions. The diagnostics consists of the leverage point and standardized predicted residual.     

Synthesis, crystal structure, and solid-state NMR spectroscopy of a salt-inclusion stannosilicate: [Na3F][SnSi3O9

A salt-inclusion stannosilicate, [Na3F][SnSi3O9], has been synthesized using a flux-growth method and characterized by single-crystal X-ray diffraction. The structure consists of six-membered silicate rings linked via corner sharing by SnIVO6 octahedra to form a 3-D framework that delimits two types of channels. The F atoms and Na atoms are located in the structural channels and form a dimer with the anti-Al2Cl6(g) structure. This stannosilicate adopts a new structure and is the first metal silicate that contains both Na+ and F- ions in the channels. The 19F and 29Si MAS NMR and 23Na MQMAS NMR spectra are consistent with the crystallographic results.