Construction of type II blow-up solutions for a semilinear parabolic system with higher dimension

This paper is concerned with blow-up solutions for a semilinear parabolic system with a power type nonlinearity. Non self-similar blow-up solution is constructed by the matched asymptotic expansions. One component of this solution converges to the singular steady state, and another component converges to zero in self-similar variables.     

Validated method using liquid chromatography-electrospray ionization tandem mass spectrometry for the determination of contamination of the exterior surface of vials containing platinum anticancer drugs

Contamination of the exterior surface of vials of cytostatic drugs by the drugs themselves is a potential hazard to human health. This study developed a validated method using liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) for the determination of contamination of the exteriors of vials of cisplatin and carboplatin. Large Alpha^® sampling swabs were employed to wipe the vial exterior. Cisplatin or carboplatin and gold(III) as an internal standard were derivatized by N,N-diethyldithiocarbamate (DDTC). Pt(DDTC)₃⁺ and Au(DDTC)₂⁺ were monitored by the respective transitions of m/z 639.3-490.9 and 493.0-345.0, respectively. Each separation was completed within 9 min using a 3 μm particle ODS-column. Calibration curves for cisplatin and carboplatin were linear over concentration ranges of 30-10,000 and 30-30,000 pg vial⁻¹, respectively. The accuracies and precisions were 96.1-102.5% and within 8.2% for intra-assay and 99.6-103.3% and within 7.6% for inter-assay, respectively. Their lower limit of quantification was 30 pg vial⁻¹. Amounts of 0.17-17.0 ng vial⁻¹ as cisplatin and 0.48-794 ng vial⁻¹ as carboplatin were detected from the exterior surface of the vials. This validated method using LC-ESI-MS/MS for the determination of platinum anticancer drugs is helpful for monitoring contamination of the exterior surface of drug vials.     

Interlaboratory study of DNA extraction from multiple ground samples, multiplex real-time PCR, and multiplex qualitative PCR for individual kernel detection system of genetically modified maize

In many countries, the labeling of grains, feed, and foodstuff is mandatory if the genetically modified (GM) organism content exceeds a certain level of approved GM varieties. We previously developed an individual kernel detection system consisting of grinding individual kernels, DNA extraction from the individually ground kernels, GM detection using multiplex real-time PCR, and GM event detection using multiplex qualitative PCR to analyze the precise commingling level and varieties of GM maize in real sample grains. We performed the interlaboratory study of the DNA extraction with multiple ground samples, multiplex real-time PCR detection, and multiplex qualitative PCR detection to evaluate its applicability, practicality, and ruggedness for the individual kernel detection system of GM maize. DNA extraction with multiple ground samples, multiplex real-time PCR, and multiplex qualitative PCR were evaluated by five laboratories in Japan, and all results from these laboratories were consistent with the expected results in terms of the commingling level and event analysis. Thus, the DNA extraction with multiple ground samples, multiplex real-time PCR, and multiplex qualitative PCR for the individual kernel detection system is applicable and practicable in a laboratory to regulate the commingling level of GM maize grain for GM samples, including stacked GM maize.     

Femtosecond Diffuse-Reflectance Spectroscopy of Various Commercially Available TiO2 Powders

The transient absorption properties of several commercially available TiO₂ photocatalysts were investigated by femtosecond diffuse-reflectance spectroscopy. Using femtosecond diffuse-reflectance spectroscopy, the quantities and rates of the initial trapping processes of holes and electrons generated by the photoexcitation of TiO₂ photocatalysts were investigated. It was found that the total amounts of trapped electrons for the pure-anatase and pure-rutile TiO₂ became smaller with increasing particle size, but increased again when the particles’ diameters were larger than 50 nm. The anatase–rutile mixed TiO₂ photocatalysts were found to have smaller amounts of trapped electrons compared with pure-anatase and pure-rutile TiO₂ photocatalysts. The lifetimes of trapped holes of various TiO₂ photocatalysts were also investigated, and it was found that the lifetimes were proportional to the anatase–rutile mixed ratios.     

NON-CLASSICAL ASYMPTOTICS OF THE TRACE OF THE HEAT KERNEL FOR THE MAGNETIC SCHRÖDINGER OPERATOR

We consider the effect of a magnetic field for the asymptotic behavior of the trace of the heat kernel for the Schrödinger operator. We discuss the case where the operator has compact resolvents in spite of the fact that the electric potential is degenerate on some submanifold. According to the degree of the degeneracy, we obtain non-classical asymptotics.     

Conductive liquid crystalline compounds having a piperazine structure

New conductive thermotropic liquid crystalline materials having a piperazine ring in the central core: 1-[4-(9-decenyloxy)phenyl]-4-alkylpiperazines ( 6 ) were synthesized. The mesomorphic behaviours of these compounds and their conductivity in the liquid crystal phase were measured. The principal features of these compounds are to exhibit a smectic B phase around room temperature (for example 6 : Cr 50 SmB 81 I, °C) and to exhibit a large dark current (6d: 430 μA cm^-2, applied voltage 20 V, at 70°C) in the smectic B phase.     

Use of ring-repeller, double-skimmer electrodes for efficient ion focusing in mass spectrometry.

The design and construction of a new type of time-of-flight mass spectrometer is described. The instrument was designed to improve the ionization efficiency and to efficiently detect ions. The system performance was evaluated using the SIMION software, and was compared with the experimental results. The shapes of the repeller, extraction, and ground electrodes had a strong effect on the trajectory of ions in the processes of ion acceleration and focusing. The major difference between the theory and the experiment can be attributed to space-charge effects.     

Determination of lead in seawater by flow-injection on-line preconcentration-electrothermal atomic absorption spectrometry after coprecipitation with iron(III) hydroxide.

A flow-injection on-line preconcentration-electrothermal atomic absorption spectrometric (ETAAS) method coupled with a coprecipitation method has been developed for the determination of lead in seawater. The combination of two preconcentration procedures, coprecipitation with iron(II) hydroxide and solid-phase extraction with a lead-selective resin, Pb-Spec, allowed the determination of lead at the ng kg(-1) level. Lead in 250 g of a sample solution was collected by coprecipitation with 10 mg of iron. The precipitate was dissolved in 25 ml of 1 mol l(-1) nitric acid; then, a 4-ml aliquot of the sample solution was introduced into the flow-injection system to preconcentrate and separate lead from iron on a Pb.Spec microcolumn. The sorbed lead was eluted with a 1.0 x 10(-4) mol l(-1) EDTA solution. The 30-microl portion of the eluate corresponding to the highest analyte concentration zone was injected into a graphite furnace. The overall enhancement factor was about 200 for 250 g of the sample. The average and standard deviation of ten blank values obtained were 1.7 ng and 0.38 ng, respectively. The recovery was 93.7 +/- 5.0% for seawater spiked with 20 ng kg(-1) lead. The proposed method is applicable to the analysis of seawater for lead at slightly higher levels.     

Exopeptidase degradation for the analysis of phosphorylation site in a mono-phosphorylated peptide with matrix-assisted laser desorption/ionization mass spectrometry.

The utility of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) coupled with a peptide ladder sequencing method employing exopeptidase degradation for the analysis of phosphorylation site in a mono-phosphorylated peptide is investigated. MALDI-TOFMS analysis of time-dependent exopeptidase digestion using carboxypeptidase W and aminopeptidase M of the mono-phosphorylated 33-48 fragment isolated from a beta-casein tryptic digestion mixture allowed for the sequencing analysis from both the C-terminus and N-terminus. Negative ion detection MALDI-TOFMS made it possible to clearly measure the peptide ladder of mono-phosphorylated peptide by the strong negative charge localized at the phosphoric acid group. Since exopeptidase activity was suppressed by the existence of a phosphorylated amino acid residue, the termination exopeptidase degradation therefore suggested the existence of a phosphorylated amino acid residue at that site. This peptide ladder sequencing method using exopeptidases was effective for the identification of the site of a phosphorylated amino acid residue by a simple MALDI-TOFMS analysis in the negative ion detection mode.     

Scattering of a plane wave from a periodic random surface: a probabilistic approach

This paper deals with a probabilistic formulation of the wave scattering from a periodic random surface. When a plane wave is incident on a random surface described by a periodic stationary stochastic process, it is shown by a group-theoretic consideration that the scattered wave may have a stochastic Floquet form, i.e. a product of a periodic stationary random function and an exponential phase factor. Such a periodic stationary random function is then written by a harmonic series representation similar to a Fourier series, where Fourier coefficients are mutually correlated stationary processes instead of constants. The mutually correlated stationary processes are represented by Wiener - Hermite functional series with unknown coefficient functions called Wiener kernels. In case of a slightly rough surface and TE wave incidence, low-order Wiener kernels are determined from the boundary condition. Several statistical properties of the scattering are calculated and illustrated in figures.