Complexation of a hydrophobic thiazorylazophenol with Ni2+ at sodium dodecylsulfate micellar surface

Complexation of thiazorylazododecylphenol (TADP) with Ni2+ at the surface of sodium dodecylsulfate (SDS) micelles has been spectrophotometrically studied. Complicated spectral changes are analyzed by a factor and multivariate analysis, which implies the formation of [TDAP(OH-)Ni]0 as well as a simple 1:1 complex of Ni2+ with TDAP at the micellar interface. All of the equilibrium constants required to describe this system are substantially affected by electrolyte concentrations. Coexistent electrolytes vary the surface potential of the micelle, and in turn influence the equilibria taking place on the micellar surface. The electrostatic potential estimated based on the equilibrium shifts is more negative than that calculated according to Poisson-Boltzmann theory, which simply involves electrostatic effects. This disagreement is possibly caused by different aqueous environments around the micelle from bulk solution, which also facilitate the formation of unusual complex such as [TDAP(OH-)Ni]0.     

DNA PHOTOREACTIVATING ENZYME FROM SILKWORM

An ammonium-sulfate-precipitable (33–70%) fraction in extracts from eggs of silkworm Bombyx mori contains photoreactivating enzyme that reactivates the transforming activity of UV inactivated Hemophilus influenzae DNA. The action spectrum for in vitro photoreactivation with the enzyme has a broad peak around 365–385 nm, with a shoulder extending to 460 nm. This relatively higher photoreactivation efficiency at wavelengths longer than 450 nm seems to be a unique feature of DNA photoreactivating enzyme of silkworm. Using gel filtration, a mol wt of 42,000 was estimated for the enzyme. Optimum and isoionic pH of the enzyme were 7.2 and 5.4, respectively. These properties of silkworm enzyme are within the range of variations in reported biochemical characteristics of photoreactivating enzymes from different species.     

Solving the Huff-Based Competitive Location Model on a Network with Link-Based Demand

This paper shows a computational method for optimizing the location of a store on a network in a competitive environment, assuming that consumers probabilistically choose stores following the Huff model (1963) and that the store can be located on a continuum of a network. This method gives the exact optimal solution with the computational order of n _N ² logn _N where n _N is the number of nodes of the network.     

A Bayesian approach to pricing longevity risk based on risk-neutral predictive distributions

We present a Bayesian approach to pricing longevity risk under the framework of the Lee-Carter methodology. Specifically, we propose a Bayesian method for pricing the survivor bond and the related survivor swap designed by Denuit et al. (2007). Our method is based on the risk neutralization of the predictive distribution of future survival rates using the entropy maximization principle discussed by Stutzer (1996). The method is illustrated by applying it to Japanese mortality rates.     

Chemical component mapping of pulverized toner by scanning transmission X-ray microscopy

Toners are micron scale polymer particles constructed of several kinds of resin, pigment, wax, etc. Transmission electron microscopy (TEM) is used for observation of the dispersion of the component materials in toners, but TEM images cannot identify simultaneously all components. Scanning transmission X-ray microscopy (STXM) not only provides simultaneous observation of spatial distributions of wax, resin and carbon black in toners, but it also provides detailed, quantitative, chemical information about the wax and resin environments through chemical component maps derived from multiple energy image sequences. The capabilities of STXM for toner analysis are illustrated by results of a study of a toner for black/white copy/print applications.     

Sequential location—allocation of public facilities in one- and two-dimensional space: Comparison of several policies

The present paper examines the sequential location—allocation problems of public facilities in one- and two-dimensional space under several policies. It is shown that the efficiency loss due to the adoption of a myopic policy is not so large, contrary to common belief, provided that the efficiency can be measured by the total transportation cost of users and by the total capacity of facilities. If the total serving area is sufficiently narrow, then the spatial allocations of optimal solutions in two-dimensional problems can be closely approximated by those in one-dimensional problems.     

Assessment of the natural radioactivity using two techniques for the measurement of radionuclide concentration in building materials used in Japan

The specific activities of ²³⁸U, ²³²Th, and ⁴⁰K in selected building materials used in Japan were measured using a high-purity germanium detector. The uranium and thorium concentrations were determined from same samples using inductively coupled plasma mass spectrometry. There was a good agreement between the measurement of uranium and thorium with both methods (R ² = 0.94, and 0.97, respectively). Based on the specific activities, we have estimated some hazard indexes such as radium equivalent activities (Ra _eq), external hazard index (H _ex), internal hazard index (H _in), annual gonadal equivalent dose (AGED), internal alpha dose, mass exhalation rate and emanation coefficient of radon.     

A novel, mild, and facile method to prepare 6-methylidene penem derivatives

A novel and mild method was established to synthesize 6-methylidene penem compounds. This method entails a MgBr(2)/Et(3)N-promoted aldol-type condensation on 6-bromopenem 12 with an appropriately substituted aldehyde to yield the intermediate acetylated bromohydrin, which was smoothly converted to the final product with simultaneous deprotection of C3 carboxylic acid ester using activated zinc dust and phosphate buffer at pH 6.5. This process provides a useful variation of C-C bond formation method for penem derivatives and also serves as a practical synthetic method to prepare 6-exomethylenepenem derivatives without racemization at the C5 position.     

Radon concentration of outdoor air: measured by an ionization chamber for radioisotope monitoring system at radioisotope institute

Gas-flow ionization chambers for radioisotope (RI) monitoring systems at RI institutes throughout Japan are commonly used to measure RIs which leak from the RI institutes. Before the Japan’s 2011 Tohoku earthquake [11 March 2011, moment magnitude (M _w) 9.0], ionization current data measured with a gas-flow ionization chamber at the RI institute of Fukushima Medical University were found to change. The question we must raise is whether the variation ionization current can be considered to the variation of outdoor radon concentration. The conversion factors (from ionization current to radon concentration in air) of the gas-flow ionization chamber can be obtained by measuring four levels of radon concentration (outdoor air, indoor air, high level and radon-free gas) with an AlphaGUARD monitor and the chamber itself. The two gas-flow ionization chambers consist of the air intake and terminal exhaust duct of the RI institute. It was found that the radon concentration in the exhaust air was the same as that in the air intake. This study provided evidence that variations of outdoor radon concentration could be determined using gas-flow ionization chambers for RI monitoring systems.