Design and synthesis of Mg2+-selective fluoroionophores based on a coumarin derivative and application for Mg2+ measurement in a living cell

Novel Mg2+ fluorescent molecular probes (KMG-20-AM and KMG-27-AM; where AM is an acetoxymethyl group) based on a coumarin possessing a charged beta-diketone structure were designed and synthesized. These fluorescent probes produced a red shift from 425 to 445 nm in the absorption spectra after formation of a complex with Mg2+. The fluorescence spectra of these probes also showed a red shift from 485 to 495 nm and an increasing fluorescence intensity after formation of a complex with Mg2+. The optimum experimental conditions were excitation wavelength of 445 nm and a monitored wavelength of 500 nm, where these probes functioned as an indicator showing an image of increasing fluorescence in the presence of Mg2+. These probes showed a "seesaw-type" fluorescent spectral change with the isosbestic point at 480 nm due to the light excitation at 445 nm, which indicates that ratiometry can be used for the measurement. The molecular probes formed a 1:1 complex with Mg2+ and the dissociation constant (Kd) was 10.0 mM for KMG-20. The association constants of the probes with Mg2- were approximately 3 times higher than that with Ca2+, which showed that the selectivity of Mg2+ versus Ca2+ for these probes was over 200 times higher than that for commercially available Mg2+ fluorescent molecular probes such as mag-fura-2, Magnesium Green. As an application of these probes, intracellular fluorescent imaging of Mg2+ was demonstrated using a fluorescent microscope. After the addition of KMG-20-AM and KMG-27-AM into PC12 cells, a strong fluorescence was observed in the cytoplasm and a weak fluorescence in the nuclei region. After treatment with a high-K+ medium, the fluorescence intensity increased due to increasing intracellular Mg2+. The real image of Mg2+ release from the magnesium store was successfully observed with these Mg2+ fluorescent probes.     

Formation of Microcrystalline α-Alumina by Glycothermal Treatment of Gibbsite

Microcrystalline α-aluminas (hexagonal plates, ∼0.1 μm wide and ∼0.025 μm thick) were prepared by treating fineparticle gibbsite in glycol at 300°C under the spontaneous vapor pressure of glycol (glycothermal treatment). The α-alumina was formed by the collapse of the glycol derivative of boehmite.     

A Novel Thermosensitive Poly(methyl 2-acetamidoacrylate)

The thermosensitive properties of aqueous poly(methyl 2-acetamidoacrylate) (PMAA) solutions were investigated in the absence or presence of sodium sulfate. Poly(methyl 2-acetamidoacrylate) with a molecular weight of 23,000 (PMAA-1) exhibited the cloud point. On heating the PMAA-1 solution, the transmittance began to decrease from near 34°C and increased again after the minimum value was shown at 36.0°C. The minimum transmittance increased linearly with an increasing concentration of the polymer although the minimum-transmittance temperature did not depend on polymer concentration. The minimum transmittance was affected by the pH and the 1-butanol added. This finding suggests that the cloudiness is controlled by a delicate balance of hydrophilicity and hydrophobicity and by intra- and/or inter-molecular hydrogen bonding. Poly(methyl 2-acetamidoacrylate) with a molecular weight of 15,000 (PMAA-2) did not exhibit cloudiness in distilled water. However, the addition of sodium sulfate caused cloudiness to appear. The cloud point of a PMAA-2 solution depended on concentrations of polymer and salt added. It decreased with an increase in polymer and salt concentrations. The salting-out constants were determined from the relationship between the cloud point and concentrations of polymer and salt.     

Effects of channel wall material on thrust performance and plasma characteristics of Hall-effect thrusters

The effects of channel wall material on Hall thruster performance and on plasma characteristics were investigated. A laboratory-model Hall thruster THT-III was operated with three channel wall materials of BN, BNSiN and BNAlN. Both the discharge current and the thrust were affected by the nature of the channel wall materials. The measured axial distributions of wall and plasma potentials, radial and axial electron temperatures, and electron number density near the channel walls showed that the wall material affected ionization region and ion wall loss in the channel, resulting from secondary electron emission, although ion acceleration region was determined by the axial distribution of radial magnetic field. The difference in discharge current between channel wall materials was attributed to the difference in axial current density near the inner channel wall, depending on secondary electron emission.     

Photo-catalytic film deposition by atmospheric TPCVD

TiO₂ film were deposited by atmospheric thermal plasma chemical vapor deposition (TPCVD) method to investigate the rapid process for functional film deposition. The experiment was conducted under the condition where working gas was Ar, working gas flow rate was 20 l/min, deposition distance was varied from 30 to 200 mm and spraying time was 10 min. Ethanol diluted titanium tetra buthoxide was used as starting material. Consequently, even in this process TiO₂ films including anatase could be deposited, and the results of wettability and methylene blue decoloration testings suggest that the TiO₂ films have good photo-catalytic property. Besides, by using extension nozzle, columnar structure film could be deposited due to a perfect starting material vaporization. From these results, the proposed process seemed to be highly promising for the rapid formation of functional thin films.     

A Note on the Evaluation of the Agglomerative Hierarchical Clustering Methods

Behaviormetrika - Recently, a large number of techniques of numerical taxonomy or cluster analysis are proposed and studied by many workers, and the needs for these techniques arise in many fields...     

Viscoelastic evaluation of effects of fiber size and composition on cellulose‐polypropylene composite of high filler content

In wood/plastic composite of high wood filler content, filler dispersion in resin is important which determines mobility of compound and mechanical properties of products. This work reports on the dispersion of components in compound by evaluation of viscoelasticity using a cone rheometer. The effects of size of cellulose fiber and resin content on viscoelasticity were analyzed, and the dispersion of cellulose is discussed to reach the following conclusions: The viscoelasticity measured by a cone rheometer was dependent on the dispersion state of compound, and evaluation of viscoelasticity affords the evidence for dispersion state of filler in compound; On the basis of viscoelastic evaluation of compound with different resin content, a model for dispersion of cellulose and resin with tangle of fiber is proposed; Viscoelastic analysis showed that cellulose size has influence on tangle of fiber, and results of viscoelasticity and mechanical properties of mold products suggested that an important factor determining tangle of fiber is its average aspect ratio. The proposed analysis of viscoelasticity presents a new technique for estimating the dispersion state of compound of high filler content which is hardly accessible by conventional fluid evaluation methods. The present method is simple and useful for quality control in manufacture. POLYM. ENG. SCI., 2008. © 2007 Society of Plastics Engineers     

Cancer Malignancy Is Correlated with Upregulation of PCYT2-Mediated Glycerol Phosphate Modification of α-Dystroglycan

The dystrophin–glycoprotein complex connects the cytoskeleton with base membrane components such as laminin through unique O-glycans displayed on α-dystroglycan (α-DG). Genetic impairment of elongation of these glycans causes congenital muscular dystrophies. We previously identified that glycerol phosphate (GroP) can cap the core part of the α-DG O-glycans and terminate their further elongation. This study examined the possible roles of the GroP modification in cancer malignancy, focusing on colorectal cancer. We found that the GroP modification critically depends on PCYT2, which serves as cytidine 5′-diphosphate-glycerol (CDP-Gro) synthase. Furthermore, we identified a significant positive correlation between cancer progression and GroP modification, which also correlated positively with PCYT2 expression. Moreover, we demonstrate that GroP modification promotes the migration of cancer cells. Based on these findings, we propose that the GroP modification by PCYT2 disrupts the glycan-mediated cell adhesion to the extracellular matrix and thereby enhances cancer metastasis. Thus, the present study suggests the possibility of novel approaches for cancer treatment by targeting the PCYT2-mediated GroP modification.