Effect of surface structure on cell growth prepared by the terminal immobilization method

Substrate effects of surface morphology and chemical structure for cell cultures prepared by molecular terminal immobilization method were studied. When we focused attention on a phenyl group as a functional moiety, the cell growth on the surface prepared by the immobilization method showed a better proliferation rate than that of a substrate prepared by the casting method. Further, from the results of mouse fibroblast L929 cell (L‐cell) growth on poly(amino acid)‐immobilized surfaces in Dulbecco's minimal essential medium containing 10% FBS, it was indicated that the amino group was more effective than the phenyl group, and that a slight difference of chemical structure had a substantial influence on cell growth. In addition, mouse bone marrow–derived Sp2/0‐Ag14 cell (Sp2/0 cell) culture in ASF‐104 serum‐free medium, poly(amino acid)‐immobilized substrates showed an almost equal proliferation rate to that in a serum‐containing medium. These results showed that effective cell growth can occur on immobilized surfaces, and that detection of a weak interaction depends on the functional groups. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3001–3008, 2004     

Pectin‐[(3‐acrylamidopropyl) trimethylammonium chloride‐co‐acrylic acid] hydrogel prepared by gamma radiation and selectively silver (Ag) metal adsorption

Pectin‐[(3‐acrylamidopropyl) trimethylammonium chloride‐co‐acrylic acid] hydrogel has been prepared from the aqueous blend solution of pectin, (3‐acrylamidopropyl) trimethylammonium chloride (APTAC), and acrylic acid (AAc) by applying gamma radiation of different doses (1–25 kGy) from ⁶⁰Co gamma source. The hydrogels were characterized by equilibrium swelling, Fourier transform infrared, differential scanning calorimetry, and scanning electron microscopy. The hydrogels were used in multielement adsorption and it was found that pectin‐(APTAC‐co‐AAc) gel is highly selective toward silver (I) ion among 27 metal ions. The data obtained from equilibrium adsorption studies were fitted in Langmuir and Freundlich adsorption isotherm models and model parameters evaluated. The maximum adsorption capacity of pectin‐(APTAC‐co‐AAc) gel was found to be 67.6413 mg/g of dry gel at sample volume of 25 mL. The kinetic data were tested using pseudo‐first order and pseudo‐second order kinetic models and different adsorption diffusion models such as film diffusion and intra‐particle diffusivity model. Thiourea solution was used for desorption of adsorbed metal ions from the hydrogel. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45906.     

Structure Control of Calcium Silicate Hydrate Gels for Dye Removal Applications

The structure of calcium silicate hydrate (C‐S‐H) gels was modified by hydrothermal reaction with aqueous acetic acid solvent, and then the C‐S‐H gels were used for dye removal from aqueous solution. With increasing acetic acid concentration, the Ca:Si molar ratio decreased and the length of the silicate anion chain structure of the C‐S‐H gels increased. The silicate anion chain length affects the number of available silanol groups on the surface of the C‐S‐H gel: the longer the silicate anion chain length, the greater the number of negative charges and the higher the surface potential. C‐S‐H gels with a long silicate anion structure exhibited higher adsorption capacity for methylene blue than gels with a short silicate anion structure. The enhanced adsorption capacity of the C‐S‐H gels is related to the higher number of silanol groups in the bridging silica tetrahedra of the intermediate anion chain structure compared with those in the end units of silica tetrahedra.     

A new empirical model for self-leveling behavior of cylindrical particle beds

ABSTRACT

During the material relocation phase of core disruptive accidents in sodium-cooled fast reactors, the rapid quenching and fragmentation of molten materials discharged from the reactor core into the lower plenum region can lead to the formation of debris beds. Coolant boiling may lead to leveling of the mound-shaped beds, which changes both the beds' coolability with decay heat in the fuel and the neutronic characteristics. In this study, a series of experiments using simulant materials were performed to develop an experimental database of self-leveling processes of particle beds in a cylindrical system. To simulate the coolant boiling in the beds in the experiments, a gas injection method was used to percolate nitrogen gas uniformly through the base of a bed with a conical-shaped mound. Time variations in bed height during the self-leveling process were measured for different particle sizes, densities and sphericities, and gas injection velocities. Using a dimensional analysis approach, a new model was proposed. This model correlates the experimental data on transient bed height with an empirical equation using a characteristic time for self-leveling development and an equilibrium bed height. The proposed model reasonably predicts the self-leveling development of particle beds.     

A Linear Time Algorithm for L(2,1)-Labeling of Trees

An L(2,1)-labeling of a graph G is an assignment f from the vertex set V(G) to the set of nonnegative integers such that |f(x)?f(y)|≥2 if x and y are adjacent and |f(x)?f(y)|≥1 if x and y are at distance 2, for all x and y in V(G). A k-L(2,1)-labeling is an L(2,1)-labeling f:V(G)→{0,…,k}, and the L(2,1)-labeling problem asks the minimum k, which we denote by λ(G), among all possible assignments. It is known that this problem is NP-hard even for graphs of treewidth 2, and tree is one of very few classes for which the problem is polynomially solvable. The running time of the best known algorithm for trees had been O(Δ ^4.5 n) for more than a decade, and an O(min{n ^1.75,Δ ^1.5 n})-time algorithm has appeared recently, where Δ and n are the maximum degree and the number of vertices of an input tree, however, it has been open if it is solvable in linear time. In this paper, we finally settle this problem by establishing a linear time algorithm for L(2,1)-labeling of trees. Furthermore, we show that it can be extended to a linear time algorithm for L(p,1)-labeling with a constant p.     

Drawing Borders Efficiently

A spreadsheet, especially MS Excel, is probably one of the most popular software applications for personal-computer users and gives us convenient and user-friendly tools for drawing tables. Using spreadsheets, we often wish to draw several vertical and horizontal black lines on selective gridlines to enhance the readability of our spreadsheet. Such situations we frequently encounter are formulated as the Border Drawing Problem (BDP). Given a layout of black line segments, we study how to draw it efficiently from an algorithmic view point, by using a set of border styles and investigate its complexity. (i) We first define a formal model based on MS Excel, under which the drawability and the efficiency of border styles are discussed, and then (ii) show that unfortunately the problem is -hard for the set of the Excel border styles and for any reasonable subset of the styles. Moreover, in order to provide potentially more efficient drawing, (iii) we propose a new compact set of border styles and show a necessary and sufficient condition of its drawability.     

Natural-convection heat transfer to air from a horizontal array of cylinders with different surface temperatures

Heat transfer measurements were made on natural convection around horizontal in-line arrays of cylinders whose surface temperatures were different from each other. Through the experiments for a three-cylinder array, a correlation was obtained for the heat transfer coefficient of the array-center cylinder. By using the correlation with some assumptions, the heat-flux distributions could be estimated for an array of five cylinders which were heated to their respective temperatures. Consequently, it was found that both the correlation and the method proposed here were useful in the estimation of heat-flux distributions for a horizontal array of cylinders. © 1998 Scripta Technica, Inc. Heat Trans Jpn Res, 26(2): 116–121, 1997     

Development of self-vibration/detection AFM probe using quartz tuning fork

We present a novel type of quartz tuning-fork probe, which oscillates and detects its own probe deformation, for atomic force microscopy (AFM) systems. The quartz tuning-fork structure was fabricated using anisotropic wet etching, and a sharp tip was formed on a beam using a focused ion beam (FIB) system. We evaluated the vibration properties of the fabricated tuning fork with the tip structure in an anti-phase vibration mode and obtained a Q-factor value of 2.5 to 2.8 × 10³. This value was one order larger than that of a conventional Si probe. We experimentally clarified that the tuning-fork probe measured a 100-nm step of the Si surface, as well as the debris with a thickness of a few tens of nanometers on the surface by self-vibration and self-detection in cyclic-contact mode AFM. Copyright © 2009 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.