A new measurement of thermal conductivity of amorphous ice and its implications for the thermal evolution of comets

Very slowly deposited amorphous ice has a thermal conductivity about four orders of magnitude or more smaller than hitherto estimated. Using the exceedingly low value of the thermal conductivity of comets deduced from the properties of amorphous ice leads to the expectation that internal heating of comets is negligible below the outer several tens of centimeters

Maxillary removable partial denture combined with O’ring attachment implant: a case report

Oral rehabilitation with free-end removable partial denture (RPD) is one of the major challenges in prosthodontic dentistry. The absence of a distal abutment produces undesirable RPD movement during masticatory function due to the high resilience of the residual ridge, which limits the denture efficiency and may damage the abutment teeth and bone over time. The advent of dental implants made possible to substitute the missing teeth with fixed implant-supported dentures as the first choice treatment to overcome such inconveniences. However, this indication may not be suitable for all patients due to financial, anatomical or systemic health conditions. Nevertheless it is possible to improve free extension RPD by using implants in the posterior edentulous ridge to achieve biological, biomechanical, physiological and social benefits. This article aims to present a case report on oral rehabilitation in which a RPD was made combined with an implant for posterior support in a sizeable edentulous ridge. The patient appreciated the retention improvement and the aesthetic result. The combination of a RPD with a posterior implant is an alternative treatment for cases in which implant-supported fixed prosthesis is not indicated, reducing the displacement and minimizing the limitations of the free-end devices.A reabilitação por meio de p rótese parcial removível (PPR) para os c asos de e xtremidade livre d istal é um dos g randes desafios da reabilitação oral. A ausência de pilar posterior promove maior movimentação da PPR durante a função, devido à resiliência da fibromucosa. Com o advento dos implantes, esses passaram a ser a primeira alternativa de tratamento para arcos com essa configuração. Entretanto, nem todos os casos podem se beneficiar dessa indicação, considerando as condições financeiras, estruturais ou de ordem sistêmica do paciente. Para m elhorar o suporte posterior da PPR, é possível associá-la a os i mplantes no espaço edentado, buscando benefícios b iológicos, biomecânicos, sociais e fisiológicos. Nesse sentido, o objetivo desse trabalho é apresentar um caso clínico utilizando implante conjugado com PPR na reabilitação de um espaço edentado considerado grande. Ao final, a paciente se mostrou satisfeita com a estética e melhora da retenção. Portanto, a associação de PPR com implante é uma alternativa de tratamento aos pacientes que não podem ser submetidos a próteses fixas implanto suportadas, além de proporcionar a redução do deslocamento da extremidade livre desses aparelhos

Effect of framework type on survival probability of implant-supported temporary crowns : an in vitro study

This in vitro study evaluated the effect of framework type on the survival probability of temporary implant-supported crowns and on the implant platform structure after dynamic fatigue. Thirty (30) external hexagon implants (3.75 x 10 mm) were embedded in acrylic resin following the ISO-14801. Standardized temporary crowns (n=10, N=30) were manufactured in acrylic resin and divided according to the framework type: Total plastic, Plastic with CoCr base and Titanium. The crowns were installed onto the implants (20N.cm) and fatigued (100N, 2 Hz) to determine the crowns? survival probability for missions of 300.000 and 600.000 cycles. Fatigue data were submitted to the Kaplan-Meier test followed by Wilcoxon and Log Rank, all with ? = 5%. The implant platforms were parametrically inspected based on the scanning before and after the fatigue to evaluate the damage. The strain values were analyzed using One-way ANOVA and Tukey test, all with ? = 5%. ANOVA revealed that the Total plastic showed less implant damage (-0.07 ± -0.03 mm) than the Plastic with CoCr base (-0.08 ± -0.04 mm) and the Titanium (-0.10 ± -0.01 mm) frameworks. Therefore, the framework type to manufacture implant-supported temporary crowns influences the fatigue survival of the restoration and the implant platform damage. The Plastic with CoCr base and Titanium frameworks showed superior reliability than the Total plastic framework which could not survive 600,000 cycles. The Plastic with CoCr base and the Titanium framework are suitable for restorations over 3 months in use, without a difference in the implant platform damage

Sensitivity Improvement of Infrared Imaging Video Bolometer for Divertor Plasma Measurement

The sensitivity of an infrared imaging video bolometer (IRVB) was improved for the measurement of relatively low energy plasma radiation from the viewpoint of the metal foil absorber material. The photon energy of the radiation was considered up to 1 keV for the divertor plasma measurement. The thickness of the foil absorber was evaluated not only for conventional heavy elements, e.g., platinum, but also for light elements by the relation between the photon energy and attenuation length and by mechanical strength. A heat-transfer calculation using ANSYS suggested that light elements with practical foil thickness provide a higher temperature rise of the foil absorber compared with heavier elements with practical foil thickness. The maximum of the temperature rise was evaluated using He–Ne laser irradiation onto absorber samples. The material dependence of the temperature rise has a similar tendency between calculations and experiments. Experimentally, the sensitivity of the IRVB improved from 280 to 110 µW/cm2 using titanium with 1 µm thickness compared with conventional platinum with 2.5 µm thickness. Consequently, the signal-to-noise ratio of the IRVB could be improved from 2.8 to 9.1

Single-Cell Transcriptome Analysis Dissects the Replicating Process of Pancreatic Beta Cells in Partial Pancreatectomy Model

膵臓ベータ細胞の増殖プロセスを時系列解析 --糖尿病の新規治療開発に期待--. 京都大学プレスリリース. 2020-12-24.Heterogeneity of gene expression and rarity of replication hamper molecular analysis of β-cell mass restoration in adult pancreas. Here, we show transcriptional dynamics in β-cell replication process by single-cell RNA sequencing of murine pancreas with or without partial pancreatectomy. We observed heterogeneity of Ins1-expressing β-cells and identified the one cluster as replicating β-cells with high expression of cell proliferation markers Pcna and Mki67. We also recapitulated cell cycle transition accompanied with switching expression of cyclins and E2F transcription factors. Both transient activation of endoplasmic reticulum stress responders like Atf6 and Hspa5 and elevated expression of tumor suppressors like Trp53, Rb1, and Brca1 and DNA damage responders like Atm, Atr, Rad51, Chek1, and Chek2 during the transition to replication associated fine balance of cell cycle progression and protection from DNA damage. Taken together, these results provide a high-resolution map depicting a sophisticated genetic circuit for replication of the β-cells

Astrodynamics Science About Itokawa, Gravity and Ephemeris

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76347/1/AIAA-2006-6658-569.pd