Thermoluminescence characteristics and chemical compositions of mesostases in ordinary chondrites

Induced thermoluminescence (TL) images of ordinary chondrites, ALH-77214 (L3.4-3.5), Y-74191 (L3.6), ALH-77216 (L3.8) and ALH-78043 (L6), were measured by the TL spatial distribution readout system combined with a microscope and TL characteristics [peak temperature and peak width] of mesostases were analyzed. Their chemical compositions were also analyzed by an electron probe X-ray microanalyzer. We found that; (1) The mesostasis was responsible for much of the TL in the ordinary chondrites, (2) A mesostasis of normative anorthite compositions showed low peak temperature (∿90℃) and narrow width (∿65℃), while a mesostasis of normative albite compositions showed high peak temperature (∿125℃) and wide width (∿100℃), (3) A main phosphor in a low petrologic grade chondrite 3.5 was a high albite mesostasis, (4) Some chondrules in the same fragments of the type 3 chondrites showed no or weak TL emission and these mesostases had high normative albite. These facts suggest that in type 3 ordinary chondrites; (1) The post-accretional metamorphism cannot account for the coexistence of high albite mesostases with TL emission and no emission and a high anorthite mesostasis with TL emission, (2) Low petrologic grade chondrites 3.5 have a large population of slowly cooled chondrules

Promotion of allergic immune responses by intranasally-administrated nanosilica particles in mice

With the increase in use of nanomaterials, there is growing concern regarding their potential health risks. However, few studies have assessed the role of the different physical characteristics of nanomaterials in allergic responses. Here, we examined whether intranasally administered silica particles of various sizes have the capacity to promote allergic immune responses in mice. We used nanosilica particles with diameters of 30 or 70 nm (nSP30 or nSP70, respectively), and conventional micro-sized silica particles with diameters of 300 or 1000 nm (nSP300 or mSP1000, respectively). Mice were intranasally exposed to ovalbumin (OVA) plus each silica particle, and the levels of OVA-specific antibodies (Abs) in the plasma were determined. Intranasal exposure to OVA plus smaller nanosilica particles tended to induce a higher level of OVA-specific immunoglobulin (Ig) E, IgG and IgG1 Abs than did exposure to OVA plus larger silica particles. Splenocytes from mice exposed to OVA plus nSP30 secreted higher levels of Th2-type cytokines than mice exposed to OVA alone. Taken together, these results indicate that nanosilica particles can induce allergen-specific Th2-type allergic immune responses in vivo. This study provides the foundations for the establishment of safe and effective forms of nanosilica particles

Silica phase as a thermoluminescence phosphor in ALH-77214 (L3.4)chondrite

The induced thermoluminescence (TL) images for a slice sample of ALH-77214 (L3.4) have been measured to examine TL phosphors in type 3 ordinary chondrites with low TL sensitivity, using a TL spatial distribution readout system combined with microscope. The chemical compositions of TL phosphors were analyzed by X-ray microanalyzer. The TL emissions due to silica phases have been newly observed in two pyroxene chondrules with silica inclusions (SiO_2=97-99wt%) and one porphyritic olivine chondrule with very silica-rich mesostasis (SiO_2=84wt%), in addition to those due to feldspar crystals formed in chondrule mesostases enriched in plagioclase component. The glow curves of the silica phases (the peaks around 240-280℃) are quite different from those of the usual chondrule mesostases (the peaks around 80-120℃). We have tried to utilize glow curves of induced TL for five silica phases (hydrothermal quartz, volcanic quartz, tridymite, cristobalite and silica glass). From similarities of the shape of glow curve, the silica phase was tentatively identified to be cristobalite. Utilizing silica phases as a common TL phosphor, we can make a comparative study of TL characteristics among chondritic meteorites

Evaluation Method for Thermal Environment in Residential Houses Using Score on Warmth

The purpose of this study is to verify whether the score on warmth corresponds to the actual rating of subjects with regard to thermal comfort and satisfaction. Experiments were carried out in an experimental house in a climate chamber under five different thermal conditions, in which different combinations of air and floor temperatures were controlled by floor heating or air-conditioning systems. Twenty-four subjects rated their thermal sens2ation and satisfaction in each condition, and evaluated the thermal environment on a 100-point scale. The results of this experiment are as follows. It was suggested that score on warmth based on operative temperature and floor temperature more appropriately evaluates the living environment in Japan than the Predicted Mean Vote model, which assumes uniformity of the thermal environment. The score on warmth is considered a useful thermal environment index, which evaluates the comfort and satisfaction of residential houses in Japan. The score on warmth was 2.8 points when the percentage of comfort rating was more than 80%, and was 3.0 points when the percentage was more than 90%. In conclusion, these results show that it is possible to predict the risk of catching a cold in winter using the score on warmth

Collagen XVII deficiency alters epidermal patterning

Vertebrates exhibit patterned epidermis, exemplified by scales/interscales in mice tails and grooves/ridges on the human skin surface (microtopography). Although the role of spatiotemporal regulation of stem cells (SCs) has been implicated in this process, the mechanism underlying the development of such epidermal patterns is poorly understood. Here, we show that collagen XVII (COL17), a niche for epidermal SCs, helps stabilize epidermal patterns. Gene knockout and rescue experiments revealed that COL17 maintains the width of the murine tail scale epidermis independently of epidermal cell polarity. Skin regeneration after wounding was associated with slender scale epidermis, which was alleviated by overexpression of human COL17. COL17-negative skin in human junctional epidermolysis bullosa showed a distinct epidermal pattern from COL17-positive skin that resulted from revertant mosaicism. These results demonstrate that COL17 contributes to defining mouse tail scale shapes and human skin microtopography. Our study sheds light on the role of the SC niche in tissue pattern formation. Mammals exhibit epidermal patterning, as seen in mouse tail scales and human skin microtopography. In this article, the authors demonstrate that type XVII collagen (COL17), a niche for epidermal stem cells, modulate epidermal patterning in mice and humans. COL17 further prevents wound-induced epidermal deformation. This study paves the way for elucidating the role of the stem cell niche in tissue pattern formation