Abelian Categories from Triangulated Categories via Nakaoka–Palu’s Localization

Applied Categorical Structures - The aim of this paper is to provide an expansion of Abe–Nakaoka’s heart construction to the following two different realizations of the module category...     

Enantioselective Total Synthesis of (+)‐Neostenine

A chirality transfer approach using acyclic polyol intermediates for the synthesis of (+)‐neostenine ( 1 ) has been developed. The sequential Overman/Claisen rearrangement of an allylic 1,2‐diol was especially useful, installing two contiguous stereocenters with complete diastereoselectivity in a one‐pot sequence. The SmI₂‐mediated cyclization and the subsequent chemoselective reduction of a lactam moiety accomplished the first enantioselective total synthesis of (+)‐neostenine ( 1 ).     

Effects of Si and Ti impurities on electrical properties of sol–gel-derived amorphous SrTa2O6 thin films by UV/O3 treatment

Sol–gel-derived SrTa₂O₆ thin films were fabricated at a low temperature of 500 °C. To improve their leakage current properties, additional UV/O₃-assisted annealing was performed from room temperature to 290 °C. UV/O₃ treatment at 290 °C gave a very low leakage current that was six orders of magnitude lower than that of an untreated thin film. During UV/O₃-assisted annealing, Si and Ti ions diffused from the substrates into the SrTa₂O₆ thin films and occupied the Ta⁵⁺ sites, subsequently generating Si^? and Ti^?. At a heating temperature of 290 °C, large amounts of Ti ions diffused throughout the SrTa₂O₆ thin film. These Ti ions contributed to the generation of inactive combinations of $(\mathrm{Si}^{-}\mbox{--}\mathrm{V}_{\mathrm{o}}^{+})^{+}\mbox{--}\mathrm{Ti}^{-}$ and $(\mathrm{Ti}^{-}\mbox{--}\mathrm{V}_{\mathrm{o}}^{+})^{+}\mbox{--}\mathrm{Ti}^{-}$ , which greatly reduced oxygen vacancies (V_o). Thus, the leakage current was significantly reduced.     

A synthetic approach to diverse 3-acyltetramic acids via O- to C-acyl rearrangement and application to the total synthesis of penicillenol series

For the efficient approach to medicinally important α-branched 3-acyltetramic acids, the key reaction of O- to C- acyl rearrangement using α-amino-acid-derived 4-O-acyltetramic acids was extensively examined in the presence of various metal salts. Use of CaCl(2) or NaI dramatically changed the results in the reaction efficiency and rapidly brought about the desired α-branched 3-acyltetramic acids in markedly improved yields. We also discuss an epimerization at C5 stereocenter under the rearrangement conditions as well as the tolerance for structural variation at C3 and C5. In addition to the preceding success in the total synthesis of new cytotoxic tetramic acid, penicillenol A(1), this methodology could be also applied to the first total synthesis of penicillenol A(2).     

pH sensing using boron doped diamond electrodes

The boron doped diamond (BDD) electrode is presented as an appropriate candidate for next generation glass-free, highly stable and accurate pH sensors. The method used in this study is based on the potential change related to the hydrogen evolution reaction following a current step, which is pH dependent. Alkali cations in the solution have no influence on the accuracy of the pH calibration curve, which provides an advantage with respect to the conventional pH glass electrode. The unwanted influence of electrochemically active compounds in solution can be avoided by adjusting the current density applied during chronopotentiometric measurements. The accuracy of the pH measurements is due to the excellent stability as well as the wide potential window and low background current of BDD electrodes. This faculty was not observed when using conventional electrode materials. The efficacy of this new type of pH sensor has been tested using tap water as a typical real sample.     

Full-line or specialization strategy? The negative effect of product variety on product line strategy

This paper studies the product line decisions of firms under two consumer segments differing in their quality-sensitivity. We focus on a negative impact of the product variety on the consumers’ motivation to purchase, while each product is horizontally differentiated. In the presence of this impact and high fixed costs relative to variable costs, it is shown that when a highly quality-sensitive segment exists, it is always advantageous for the monopoly to specialize in only one product serving this segment. However, the appearance of a competitor can drastically change the product line in the market. Under the duopolistic setting where two firms sequentially determine their product lines, we show that the leader gains a better financial result by offering its product to the low segment for many cases, including the case where no product is offered to the high segment by either of the firms who are in equilibrium. Furthermore, we obtain another interesting result that indicates that the follower’s profit can exceed the leader’s profit when the quality-sensitivities between the two consumer segments are sufficiently different, even though the two firms are symmetric except for the order of their product offerings.     

Metal-nanoparticle-induced crystallization of amorphous Ge film using ferritin

The metal-induced lateral crystallization (MILC) of an amorphous Ge (a-Ge) thin film using Ni nanoparticles (NPs) was investigated. Ni-NPs were formed and evenly distributed onto a 30 nm thick a-Ge film by cage-shaped protein. After complete elimination of protein shell, crystal growth was performed at 400 °C. Raman spectra and electron backscatter diffraction (EBSD) studies revealed that a poly-Ge film with a maximum grain size approximately 1 μm was successfully formed. The Ni contamination in the poly-Ge film was reduced by more than one order of magnitude compared with that in the case of a conventional MILC process.     

Atmospheric concentrations of sulfur dioxide, nitrogen oxides, ammonia, hydrogen chloride, nitric acid, formic and acetic acids in the south of Vietnam measured by the passive sampling method.

A passive sampling method was applied to measure the concentrations of air pollutants, such as sulfur dioxide, nitrogen oxides, ammonia, hydrogen chloride, and nitric, formic and acetic acids, in the ambient air at four test sites in the southern region of Vietnam. The monthly averages and the average concentrations of air pollutants during the period from July 2001 to September 2002 are reported here. The concentrations of air pollutants varied widely, depending on the test sites and the sampling periods. The average concentrations of sulfur dioxide in the air during the period from July 2001 to September 2002 at the four test sites were 3.3-16.9 ppb, and those of nitrogen dioxide were 5.4-12.8 ppb. The concentrations of nitrogen monoxide and hydrogen chloride were very low at all of the test sites. The observed concentrations of all of the above-mentioned pollutants were lower than those of the Vietnamese standards of air pollutants.