Z2 oscillation of mean charge states of fast Si and Cl ions after passage through thin foils

Z₂ (target atomic number) oscillation of equilibrium charge states has been observed for 30–110 MeV Si and 70 and 110 MeV Cl ions after the passage through 22 different Z₂ foils. This oscillation may be related to the Z₂ oscillation of electron capture cross sections into the projectile K vacancy.     

A Unified Approach to the Proportional Relation for Discrete-Time Single-Server Queues

It is well known that a simple relation called proportional relation holds for some queueing models, that is, the stationary queue length distribution of one system can be expressed as the product of a constant and the distribution of another system which is different only in the buffer capacity. Recently, the proportional relation has been verified for various discrete-time single-server queues with correlated arrivals, where it has been also shown that the proportional constant can be expressed in terms of the distribution of one system. This implies that the stationary queue length distribution of one system can be completely expressed in terms of the distribution of the other system. In this paper, we consider a generalized model of discrete-time single-server queue, which covers all previous ones, and give a simple and unified proof to the proportional relation as well as the expression of the proportional constant.     

Facile fabrication of silver nanofin array via electroless plating

The fabrication of metallic nanostructures is one of the main issues in nanotechnology. This article describes the fabrication of a silver nanofin array by combining microlithography, electroless plating, and an etching technique. Fabricated Ag nanofins have a high aspect ratio (height/width = 10, width = 60 nm, height = 600 nm), and their widths and heights can be controlled by the period of electroless plating and the height of the original line pattern. An isolated Ag nanofin was proven to show metallic electrical conductivity. The current process provides a rapid and shape-designable fabrication method of metallic nanostructures.     

Revised model core potentials for second-row transition metal atoms from Y to Cd

We have produced new relativistic model core potentials (spdsMCPs) for the second-row transition-metal atoms from Y to Cd treating explicitly 4s and 4p electrons in addition to 4d and 5s electrons in the same manner as for the first-row transition-metal atoms given in [Y. Osanai, M.S. Mon, T. Noro, H. Mori, H. Nakashima, M. Klobukowski, E. Miyoshi, Chem. Phys. Lett. 452 (2008) 210]. Using suitable correlating functions together with the split valence MCP functions, we demonstrate that the present MCP basis sets show reasonable performance in predicting the electronic structures of atoms and molecules, bringing about accurate excitation energies for atoms and reasonable spectroscopic constants for AgH.     

Novel drug delivery system of hollow mesoporous silica nanocapsules with thin shells: preparation and fluorescein isothiocyanate (FITC) release kinetics

Core-shell nanoparticles of Au@silica with a diameter of approximate 45–60 nm and wall thickness in range of 3–10 nm were synthesized by using 40 and 50 nm gold nanoparticles as the templates. The mesoporous particles are regulated by 3-aminopropyltrimethoxysilane addition. Hollow mesoporous silica nanocapsules (HMSNs) were prepared by using sodium cyanide to dissolve the gold cores. The characterization of Au@silica and HMSNs by transmission electronic microscope indicated that the silica shells were uniform and smooth, and also the porosity was proved by fluorescein isothiocyanate (FITC) release experiments. The ratio of hollow core to HMSNs is more than 70%. HMSNs were subsequently used as drug carrier to investigate FITC (as a model drug) release behaviors in vitro. Fluorescent spectrometry was performed to determine the release kinetics from the HMSNs. The release profiles are significantly different as compared with the control (free FITC), which show that HMSNs are good drug carriers to control drug release, and have high potential in therapeutic drugs delivery in future applications.     

Imaging of Oral SCC Cells by Raman Micro-Spectroscopy Technique

We used Raman micro-spectroscopy technique to analyze the molecular changes associated with oral squamous cell carcinoma (SCC) cells in the form of frozen tissue. Previously, Raman micro-spectroscopy technique on human tissue was mainly based on spectral analysis, but we worked on imaging of molecular structure. In this study, we evaluated the distribution of four components at the cell level (about 10 μm) to describe the changes in protein and molecular structures of protein belonging to malignant tissue. We analyzed ten oral SCC samples of five patients without special pretreatments of the use of formaldehyde. We obtained cell level images of the oral SCC cells at various components (peak at 935 cm⁻¹: proline and valine, 1004 cm⁻¹: phenylalanine, 1223 cm⁻¹: nucleic acids, and 1650 cm⁻¹: amide I). These mapping images of SCC cells showed the distribution of nucleic acids in the nuclear areas; meanwhile, proline and valine, phenylalanine, and amide I were detected in the cytoplasm areas of the SCC cells. Furthermore, the peak of amide I in the cancer area shifts to the higher wavenumber side, which indicates the α-helix component may decrease in its relative amounts of protein in the β-sheet or random coil conformation. Imaging of SCC cells with Raman micro-spectroscopy technique indicated that such a new observation of cancer cells is useful for analyzing the detailed distribution of various molecular conformation within SCC cells.     

Rate coefficients of H-atom abstraction from ethers and isomerization of alkoxyalkylperoxy radicals

Group rate expressions for the hydrogen(H)-atom abstraction reactions from ethers by hydrogen atoms and hydroxyl(OH) radicals and the intramolecular hydrogen-transfer isomerization reactions of alkoxyalkylperoxy radicals, which result from the H-abstraction from ethers followed by the addition of O(2), have been evaluated based on the quantum chemical calculations and experimental data. With the relative method proposed in the present study, it was shown that the rate coefficients of the reactions, for which only poor experimental information is available, can be reliably evaluated by calculating and extracting the difference from the well-established reactions of alkane hydrocarbons. The major features on the H-abstraction reactions from O-adjacent sites of ethers compared to those from alkanes were the suppression of the activation energy due to the decrease of the C-H bond dissociation energy and non-next neighbor substituent effect from the alkyl group on the counter side of -O-. For the hydrogen transfer isomerization reactions, similar suppression of the activation energy as well as the change in the ring strain energy was found as a major feature.     

Photosensitization reaction-induced acute electrophysiological cell response of rat myocardial cells in short loading periods of talaporfin sodium or porfimer sodium

Electrophysiological responses of rat myocardial cells to exogenous photosensitization reactions for a short period of incubation with two photosensitizers, talaporfin sodium or porfimer sodium, were measured in a subsecond time scale. The loading period of the photosensitizer when the photosensitizer might not be taken up by the cells was selected as 15min, which was determined by the fluorescence microscopic observation. We measured the intracellular Ca(2+) concentration ([Ca(2+) ](in) ) by using a fluorescent Ca(2+) indicator, Fluo-4 AM, under a high-speed confocal laser microscope to evaluate the acute electrophysiological cell response to the photosensitization reaction. The measured temporal change in Fluo-4 fluorescence intensity indicated that the response to the photosensitization reaction might be divided into two phases in both photosensitizers. The first phase is acute response: disappearance of Ca(2+) oscillation when irradiation starts, which might be caused by ion channel dysfunction. The second phase is slow response: [Ca(2+) ](in) elevation indicating influx of Ca(2+) due to the concentration gradient. The continuous Ca(2+) influx followed by changes in cell morphology suggested micropore formation on the surface of the cell membrane, resulting in necrotic cell death.     

Deuterium kinetic isotope effects on the gas-phase reactions of C2H with H2(D2) and CH4(CD4)

Kinetics of the ethynyl (C(2)H) radical reactions with H(2), D(2), CH(4) and CD(4) was studied over the temperature range of 295-396 K by a pulsed laser photolysis/chemiluminescence technique. The C(2)H radicals were generated by ArF excimer-laser photolysis of C(2)H(2) or CF(3)C(2)H and were monitored by the chemiluminescence of CH(A(2)Δ) produced by their reaction with O(2) or O((3)P). The measured absolute rate constants for H(2) and CH(4) agreed well with the available literature data. The primary kinetic isotope effects (KIEs) were determined to be k(H(2))/k(D(2)) = 2.48 ± 0.14 and k(CH(4))/k(CD(4)) = 2.45 ± 0.16 at room temperature. Both of the KIEs increased as the temperature was lowered. The KIEs were analyzed by using the variational transition state theory with semiclassical small-curvature tunneling corrections. With anharmonic corrections on the loose transitional vibrational modes of the transition states, the theoretical predictions satisfactorily reproduced the experimental KIEs for both C(2)H + H(2)(D(2)) and C(2)H + CH(4)(CD(4)) reactions.