Design and synthesis of a novel fluorescent protein probe for easy and rapid electrophoretic gel staining by using a commonly available UV‐based fluorescent imaging system

A new fluorescent molecular probe, methyl 3‐(3,5‐bis((bis(pyridin‐2‐ylmethyl)amino)‐methyl)‐4‐hydroxyphenyl)‐2‐(5‐(dimethylamino)naphthalene‐1‐sulfonamido) propanoate, dizinc(II) chloride salt (Dansyl‐ 1 ‐Zn(II)), which possesses Zn(II) complexes and a dansyl group, was designed and synthesized to enable the detection of proteins in solution and in high‐throughput electrophoresis by using a UV‐based detection system. Dansyl‐ 1 ‐Zn(II) exhibited weak fluorescence in the absence of proteins and strong green fluorescence at approximately 510 nm in the presence of BSA upon irradiation with light at a wavelength of 345 nm. Compared with conventional protocols for in‐gel SDS‐PAGE protein staining (e.g. silver staining, SYPRO Ruby, and Oriole), the operating times of which range from 90 min to overnight, Dansyl‐ 1 ‐Zn(II) allowed 1‐step protein staining (SDS‐PAGE →Staining →Detection) and shortened the operating time (35 min) with high sensitivity (LOD: 1 ng or less) under 312‐nm or 365‐nm light excitation with orange or red emission filters, respectively. Moreover, Dansyl‐ 1 ‐Zn(II) was successfully applied to protein identification by MS via in‐gel tryptic digestion, Western blotting, and Native‐PAGE. Accordingly, Dansyl‐ 1 ‐Zn(II) may facilitate highly sensitive and high‐throughput protein detection, and it may be widely applicable as a convenient tool in various scientific and medical fields.     

First Synthesis of Cotarnone,the Key Intermediate for the Synthesis of Cotarnine

The first synthesis of cotarnone (2), a degradation product of cotarnine (1), was achieved from 2-hydroxy-3-methoxy-benzaldehyde (o-vanillin), and 2 can be converted to 1 by a known method.     

Measurements of arsenite and arsenate contained in mining river waters and leached from contaminated sediments by sequential hydride generation flow injection analysis

In this work, a new analytical method for gasifiable compounds based on sequential hydride generation flow injection analysis (SHGFIA) was applied to water analysis and leaching investigation. For water analysis, it was confirmed that 1 μg L⁻¹ As(III) and As(V) were stable for a few days when EDTA was added in the sample waters. Dissolved As(III) and total arsenic (As(III) + As(V)) were converted to AsH₃ in neutral and acidic medium, respectively, to transfer to a miniature gas scrubber (100 μL in absorber volume). The collected arsenic was successively measured by flow analysis based on molybdenum blue chemistry. With this system, changes in As(III) and As(V) concentrations of water placed with arsenic-contaminated-sediment was monitored in near real time. From these data, kinetic analyses were carried out and kinetic constant was obtained from plot of ln{(C^∞ − C)/C^∞} where C and C^∞ were leached arsenic concentration and its final concentration, respectively. It was found that rate of As(III) leaching was much faster than that of As(V) while As(V) leached more in amount compared to As(III). In this work, it was demonstrated that kinetic investigation is also one of the important application of flow analysis. The SHGFIA system showed excellent performance for leaching analysis of arsenic with discrimination of As(III) and As(V).     

Weighted scale-free networks with variable power-law exponents

We present a weighted scale-free network model, in which the power-law exponents can be controlled by the model parameters. The network is generated through the weight-driven preferential attachment of new nodes to existing nodes and the growth of the weights of existing links. The simplicity of the model enables us to derive analytically the various statistical properties, such as the distributions of degree, strength, and weight, the degree-strength and degree-weight relationship, and the dependencies of these power-law exponents on the model parameters. Finally, we demonstrate that networks of words, coauthorship of researchers, and collaboration of actor/actresses are quantitatively well described by this model.     

Synthesis and Physico-Chemical Properties of Homoleptic Copper(I) Complexes with Asymmetric Ligands as a DSSC Dye

To develop low-cost and efficient dye-sensitized solar cells (DSSCs), we designed and prepared three homoleptic Cu(I) complexes with asymmetric ligands, M1, M2, and Y3, which have the advantages of heteroleptic-type complexes and compensate for their synthetic challenges. The three copper(I) complexes were characterized by elemental analysis, UV-vis absorption spectroscopy, and electrochemical measurements. Their absorption spectra and orbital energies were evaluated and are discussed in the context of TD-DFT calculations. The complexes have high V_OC values (0.48, 0.60, and 0.66 V for M1, M2, and Y3, respectively) which are similar to previously reported copper(I) dyes with symmetric ligands, although their energy conversion efficiencies are relatively low (0.17, 0.64, and 2.66%, respectively).     

Swelling-induced Mechanochromism in Multinetwork Polymers

We report a novel and versatile approach to achieving swelling-induced mechanochemistry using a multinetwork (MN) strategy that enables polymer networks to repeatedly swell with monomers and solvents. The isotropic expansion of the first network (FN) provides sufficient force to drive the mechanochemical scission of a radical-based mechanophore, difluorenylsuccinonitrile (DFSN). Although prompt recombination generally occurs in such highly mobile environments, the resulting pink radicals are kinetically stabilized in the gels, probably due to limited diffusion in the extended polymer chains. Moreover, the DFSN embedded in the isotropically strained chain exhibits increased thermal reactivity, which can be reasonably explained by an entropic contribution of the FN to the dissociation. The utility of the MN polymers is demonstrated not only in terms of swelling-force-induced network modification, but also in the context of tunable reactivity of the dissociative unit through proper design of the hierarchical network architecture.