Enhancement of sonochemical reaction of terephthalate ion by superposition of ultrasonic fields of various frequencies

The ultrasonic reactor with dual frequency was used and the effect of frequency on the fluorescence intensity of terephthalate ion was experimentally investigated in the frequency range from 176 to 635 kHz. The sonochemical reaction fields were visualized by using sonochemical luminescence of luminol solution. Compared with the fluorescence intensity of terephthalate ion for single frequency, the fluorescence intensity for dual frequency increased. The fluorescence intensity ratio of dual frequency to single frequency had maximum value when the frequency of transducer attached at the bottom wall was comparable in magnitude to that at the side wall. In the case of dual frequency, the sonochemical reaction fields became more extensive in the reactor and more intensive around the center of the reactor.     

Striking Differences in Properties of Geometric Isomers of [Ir(tpy)(ppy)H]+: Experimental and Computational Studies of their Hydricities,Interaction with CO2, and Photochemistry

We prepared two geometric isomers of [Ir(tpy)(ppy)H]⁺, previously proposed as a key intermediate in the photochemical reduction of CO₂ to CO, and characterized their notably different ground‐ and excited‐state interactions with CO₂ and their hydricities using experimental and computational methods. Only one isomer, C‐trans‐[Ir(tpy)(ppy)H]⁺, reacts with CO₂ to generate the formato complex in the ground state, consistent with its calculated hydricity. Under photocatalytic conditions in CH₃CN/TEOA, a common reactive C‐trans‐[Ir(tpy)(ppy)]⁰ species, irrespective of the starting isomer or monodentate ligand (such as hydride or Cl), reacts with CO₂ and produces CO with the same catalytic efficiency.     

Differential Effects of Cold Exposure on Gene Expression Profiles in White Versus Brown Adipose Tissue

The thermogenic function of brown adipose tissue (BAT) is known to be markedly elevated when animals are exposed to the cold, and intensive studies have been carried out to understand the molecular basis enabling effective thermogenesis in cold-exposed animals. In this study, we used microarray analysis to examine the effects of cold exposure of animals on their gene expression profiles in white adipose tissue (WAT), which seems to function as a counterpart tissue of BAT. The results indicate that the effects of cold exposure on the gene expression profiles of WAT were much more moderate than the effects on those of BAT. Possible reasons for the different responses of BAT and WAT to cold exposure are discussed.     

A recyclable, self-supported organocatalyst based on a poly(N-heterocyclic carbene)

We report the synthesis and catalytic activity of a polymeric imidazolium salt. In contrast to the well-known resin-supported N-heterocyclic carbenes (NHCs), the material described herein affords a polymer with NHCs orthogonally positioned along a main chain upon generation in situ. The unique structural characteristics of the corresponding poly(NHC)s enabled the materials to display catalytic activities that were similar or superior to those displayed by monomeric analogues. Moreover, the new catalyst was successfully recovered and reused with minimal loss of performance over several cycles.     

Numerical simulation of cyclic voltammetry for reversible systems with complex stoichiometry

Reversible waves of voltammetry with complex non-unity stoichiometry are studied here based on theory. Numerical simulations were performed for various stoichiometric systems in which coefficients m and q were independently varied from 1 to 4 in a general reaction scheme, mO + ne⁻ ai qR. The calculation results indicate that the peak current function at complex stoichiometry differs from that at simple unity stoichiometry. The relation between the half-wave potential and the formal potential has been partially corrected from that previously reported in the literature. Parameters in the relation between the peak potential and the half-wave potential are unique for each stoichiometric system. The parameter in the relation between the peak potential and the half-peak potential is also presented here.     

On distorted probabilities and m-separable fuzzy measures

Fuzzy measures are used in conjunction with fuzzy integrals for aggregation. Their role in the aggregation is to permit the user to express the importance of the information sources (either criteria or experts). Due to the fact that fuzzy measures are set functions, the definition of such measures requires the definition of 2ⁿ parameters, where n is the number of information sources. To make the definition easier, several families of fuzzy measures have been defined in the literature.In this paper m-separable fuzzy measures are introduced. We present some results on this type of measures and we relate them to some of the previous existing ones. We study generating functions for m-separable fuzzy measures and some properties related to these generating functions.     

Synthesis and study of redox-active acyclic triazenes: toward electrochromic applications

Coupling of various 4-substituted phenyl azides with two distinct quinone-containing N-heterocyclic carbenes (NHCs) afforded the respective mono- and ditopic 1,3-disubstituted acyclic triazenes in moderate to excellent yields (38-92%). Depending on their pendant substituents (derived from the azides), the acyclic triazenes exhibited intense absorptions in the visible spectrum (359-428 nm), which were bathochromically shifted by up to Δλ=68 nm upon reduction of the quinone moiety on the component derived from the NHC. Cyclic voltammetry confirmed that the aforementioned redox processes were reversible, and a related set of UV-vis spectroelectrochemical experiments revealed that bulk electrolysis may also be used to switch reversibly the colors exhibited by these triazenes.     

Highly efficient enzymatic synthesis of 3'-deoxyapionucleic acid (apioNA) having the four natural nucleobases

The synthesis of the 3'-deoxyapionucleoside 3'-triphosphates (apioNTPs) having the four natural nucleobases and their enzymatic incorporation into a DNA-DNA primer-template have been tried. Therminator DNA polymerase was shown to incorporate these apioNTPs effectively giving 43mer DNA-apioNA chimera.     

New method for comprehensive detection of chemical warfare agents using an electron-cyclotron-resonance ion-source mass spectrometer

We developed a detection technology for vapor forms of chemical warfare agents (CWAs) with an element analysis system using an electron cyclotron resonance ion source. After the vapor sample was introduced directly into the ion source, the molecular material was decomposed into elements using electron cyclotron resonance plasma and ionized. The following CWAs and stimulants were examined: diisopropyl fluorophosphonate (DFP), 2-chloroethylethylsulfide (2CEES), cyanogen chloride (CNCl), and hydrogen cyanide (HCN). The type of chemical warfare agents, specifically, whether it was a nerve agent, blister agent, blood agent, or choking agent, could be determined by measuring the quantities of the monatomic ions or CN(+) using mass spectrometry. It was possible to detect gaseous CWAs that could not be detected by a conventional mass spectrometer. The distribution of electron temperature in the plasma could be closely controlled by adjusting the input power of the microwaves used to generate the electron cyclotron resonance plasma, and the target compounds could be detected as molecular ions or fragment ions, enabling identification of the target agents.     

The Cauchy problem for hyperbolic systems with Hölder continuous coefficients with respect to time

We discuss the local existance and uniqueness of solutions of certain nonstrictly hyperbolic systems, with Hölder continuous coefficients with respect to time variable. We reduce the nonstrictly hyperbolic systems to the parabolic ones, then we shall prove them by use of Tanabe-Sobolevski’s method.