A Novel Method for Visualizing Melanosome and Melanin Distribution in Human Skin Tissues

Melanin incorporated into keratinocytes plays an important role in photoprotection; however, abnormal melanin accumulation causes hyperpigmentary disorders. To understand the mechanism behind the accumulation of excess melanin in the skin, it is essential to clarify the spatial distribution of melanosomes or melanin in the epidermis. Although several markers have been used to detect melanosomes or melanin, no suitable markers to determine the precise localization of melanin in the epidermis have been reported. In this study, we showed that melanocore-interacting Kif1c-tail (M-INK), a recently developed fluorescent probe for visualizing mature melanosomes, binds to purified melanin in vitro, and applied it for detecting melanin in human skin tissues. Frozen skin sections from different phototypes were co-stained for the hemagglutinin (HA)-tagged M-INK probe and markers of melanocytes or keratinocytes, and a wide distribution of melanin was observed in the epidermis. Analysis of the different skin phototypes indicated that the fluorescent signals of HA-M-INK correlated well with skin color. The reconstruction of three-dimensional images of epidermal sheets enabled us to observe the spatial distribution of melanin in the epidermis. Thus, the HA-M-INK probe is an ideal tool to individually visualize melanin (or melanosome) distribution in melanocytes and in keratinocytes in skin tissues.     

Atomic Motion in Low-Coverage Helium Films Adsorbed in FSM Nanochannels

⁴He and ³He films adsorbed in nanoporous silicates have shown similar heat capacities until the quantum-fluid layer appears at coverages over the first-layer completion n ₁. To obtain information on dynamics of adatoms at low coverages below the quantum fluid region, we have done pulsed-NMR experiment at 3.3 MHz for ³He films adsorbed in straight 2.4 nm nanochannels of FSM silicates. The spin-lattice and spin-spin relaxation times T ₁ and T ₂ observed at 0.54–7 K were well described by the two-dimensional version of the Bloembergen-Purcell-Pound model. At coverages 0.4–1.7n ₁, minima of T ₁, indicating the spin correlation time τ _c of 4.8×10^?8 sec, were observed at temperatures between 6 and 3 K. With decreasing temperature, changes in T ₁ and T ₂ become small below about 1.5 K, suggesting crossover from thermally-activated motion to quantum tunneling. In contrast to large variations below n ₁, both relaxation times above n ₁ are almost independent of coverage, which is likely to indicate that τ _c is determined by interlayer exchange of adatoms. Below n ₁, onsets for localization of adatoms were suggested by a decrease in T ₂.     

Synthesis and properties of polycyclic quinones condensed with 1,6-methano[10]annulene

Two types of polycyclic quinones condensed with 1,6-methano[10]annulenes as type A: 1,6-methanonaphtho[2,3-c][10]annulene-7,12-dione 5a, and type B: 1,6-methanonaphtho[2,3-c][10]annulene-5,14-dione 18, bis(1,6-methano[10]annuleno[3,4-b; 3,4-g])anthracene-10,21-dione 20, 1,6-methanoanthraceno[2,3-c][10]annulene-5,16-dione 22, 1,6-methanotetraceno[2,3-c][10]annulene-6,17-dione 23, and 1,6-methano phenanthreno[2,3-c][10]annulene-5,6-dione 24 have been synthesized. The acene derivative 6 corresponding to that of 5a was synthesized by the reduction of quinone 5a. The physical, spectral, and chemical properties of these new compounds have been investigated.     

Synthesis and properties of polycyclic quinones condensed with 1,6-methano[10]annulene

Two types of polycyclic quinones condensed with 1,6-methano[10]annulenes as type A: 1,6-methanonaphtho[2,3-c][10]annulene-7,12-dione 5a, and type B: 1,6-methanonaphtho[2,3-c][10]annulene-5,14-dione 18, bis(1,6-methano[10]annuleno[3,4-b; 3,4-g])anthracene-10,21-dione 20, 1,6-methanoanthraceno[2,3-c][10]annulene-5,16-dione 22, 1,6-methanotetraceno[2,3-c][10]annulene-6,17-dione 23, and 1,6-methano phenanthreno[2,3-c][10]annulene-5,6-dione 24 have been synthesized. The acene derivative 6 corresponding to that of 5a was synthesized by the reduction of quinone 5a. The physical, spectral, and chemical properties of these new compounds have been investigated.     

Multiscale modeling of in-room temperature distribution with human occupancy data: a practical case study

This paper develops a method for modelling of in-room temperature distribution incorporated with data collected by human sensors. This modelling is based on a standard two-dimensional heat diffusion equation with an effective diffusion coefficient. The effective diffusion coefficient is nominally identified from characteristics of air flow inside a room and its architectural design. For modelling multiple time-scale influence of human occupancy on the in-room temperature distribution, two independent parameters—the effective diffusion coefficient and human heat input—of the equation are modulated with the human sensor data that capture spatio-temporal dynamics of the occupancy in high resolution. The developed method is applied to a practical office space in commercial building in Japan so that its effectiveness is demonstrated by comparing numerical simulations of the equation with measured data on temperature.     

Stable organic thin-film transistors using full solution-processing and low-temperature sintering silver nanoparticle inks

We have fabricated electronically stable organic thin-film transistor (TFT) devices that are fully solution-processed and adopt printed electrodes using silver nanoparticles dispersed in organic solvents, whose sintering temperatures are 100 °C or less. The bottom-contact organic TFT devices showed good electrical characteristics, and exhibited threshold voltage shifts less than 2.0 V after applying a DC bias voltage stress for 10⁴ s, which is attributed to relatively low contact resistance. These results demonstrate the feasibility of producing stable organic TFTs that are fully solution-processed at relatively low temperatures, for use in large-area flexible electronics applications.     

Tuning the luminescence color and enhancement of afterglow properties of Sr(4−x−y)CaxBayAl14O25:Eu,Dy phosphor by adjusting the composition

Color point tuning is an important challenge for improving the practical applications of various displays, especially there are very limited white color single hosts that emits in the white spectrum. In this paper, the possibility of color tuning by substituting part of host lattice cation (Sr²⁺ ions) by Ca²⁺ or Ba²⁺ ions in an efficient strontium aluminate phosphor, Sr₄Al₁₄O₂₅:Eu²⁺,Dy³⁺, is reported and found to be very promising for displays. A detail study by replacing part of Sr²⁺ with Ca²⁺ or Ba²⁺ has been investigated. X-ray diffraction study showed that crystal structure of Sr₄Al₁₄O₂₅ is preserved up to 20 mol of Ca²⁺ ion exchange while it is limited to 10 mol of Ba²⁺ ions exchange. Substantial shift in the emission band and color were observed by substitution of Sr²⁺ by Ca²⁺ or Ba²⁺ ions. A bluish-white emission and afterglow was observed at higher Ca²⁺ ions substitution. Further, partial Ca²⁺ substitutions (up to 0.8 mol) resulted in enhanced afterglow of Sr₄Al₁₄O₂₅:Eu²⁺,Dy³⁺ phosphor. However, Ba²⁺ substitution decreased the fluorescence as well afterglow of the Sr₄Al₁₄O₂₅:Eu²⁺,Dy³⁺ phosphor significantly. The enhanced phosphorescence by partial Ca²⁺ substitution is explained on the basis of increased density of shallow traps associated with higher solubility of Dy³⁺ ions in to the host lattice due to equivalent size of Ca²⁺ and Dy³⁺ ions. Thus, Ca²⁺ substitution in the Sr₄Al₁₄O₂₅:Eu²⁺,Dy³⁺ phosphor is a promising method for tuning the emission color and improving the afterglow intensity of the phosphor.