Closed-channel culture system for efficient and reproducible differentiation of human pluripotent stem cells into islet cells.

Human pluripotent stem cells (hPSCs) are thought to be a promising cell-source solution for regenerative medicine due to their indefinite proliferative potential and ability to differentiate to functional somatic cells. However, issues remain with regard to achieving reproducible differentiation of cells with the required functionality for realizing human transplantation therapies and with regard to reducing the potential for bacterial or fungal contamination. To meet these needs, we have developed a closed-channel culture device and corresponding control system. Uniformly-sized spheroidal hPSCs aggregates were formed inside wells within a closed-channel and maintained continuously throughout the culture process. Functional islet-like endocrine cell aggregates were reproducibly induced following a 30-day differentiation protocol. Our system shows an easily scalable, novel method for inducing PSC differentiation with both purity and functionality.

A high-energy 160-ps pulse generation by stimulated Brillouin scattering from heavy fluorocarbon liquid at 1064 nm wavelength.

We have achieved a high compression ratio by stimulated Brillouin scattering (SBS) consisting of two long cells. A 13-ns Nd:YAG laser pulse was temporally compressed to about 160-ps phase-conjugated pulse in heavy fluorocarbon FC-40 liquid at a 1064 nm wavelength. The maximum reflectivity of SBS process was over 80 % without an optical damage. The compressed pulse brightness was about 65-fold higher than that of the incident pulse.

Tephra stratigraphic approach to the eruptive history of Pacaya Volcano, Guatemala

Pacaya Volcano, one of the most active volcano in the world, is situated in the principal area of Guatemala. To mitigate the volcanic hazard to the area, the information of the mode and timing of the eruption is important. This study aims at revealing the tephra stratigraphy of the Pacaya-El Patrocinio scoria group (Kitamura, 1995) to demonstrate the major part of the eruptive history of Pacaya Volcano in the latest eruptive stage. Fifteen scoria/falls are identified around El Patrocinio Village and they are distributed to the West of Pacaya Volcano, hardly traceable to the Northeast. Every scoria layer is caused by a cycle of eruption, most of which are composed of several eruption phases forming fall/units or a unit of falls. The 2nd, the 3rd, the 7th, the 12th and the 14th eruption are large comparatively in the fifteen eruptions; The 1st, the 4th, the 5th, the 6th and the 13th eruption are small comparatively, and the 11th and the 15th eruption are extremely small. The scoria erupted at the 7th eruption intercalates the debris avalanche deposit and the overlying blast deposit, so that volcanic edifice collapse occurred during the scoria eruption. The 10th eruption appears to continue longer period because the erupted scoria comprises a basal scoria-fall unit and overlying numerous ash-fall units including accretionary lapilli. Three radiocarbon dates suggest that the latest eruptive stage causing the fifteen scoria-falls initiated about 1,500 yr. B.P. (NU-735) and that several latest eruptions occurred since the 16th Century (NU-733 & 734)