In this paper, we have prepared Dy-doped MgAl2O4 single crystals by the Floating Zone (FZ) method and investigated photoluminescence (PL), scintillation, and thermally stimulated luminescence (TSL) ...properties. In PL and scintillation, origins of luminescence at around 480, 580, and 660 nm of synthesized crystals were assigned to the 4f–4f transitions of Dy3+. In TSL, three glow peaks at around 50, 220, and 350 °C were observed, and these peaks were attributed to cation antisites and V center. The 0.1 % Dy-doped MgAl2O4 single crystal showed the highest intensity in TSL glow curves among the prepared crystals and higher sensitivity than those in ceramic-form MgAl2O4.
1Eu
2
O
3
–3BaO–20Nb
2
O
5
–76TeO
2
glass and the corresponding glass-ceramics were synthesized with the aim to investigate the effect of glass crystallization on the photoluminescence and ...scintillation characteristics. Glass ceramics containing mainly the Nb
2
Te
4
O
13
crystalline phase were obtained by heat treatment of the glass at 540 °C for 1, 2, or 4 h. For the glass and glass ceramics, emission peaks originating from the 4f → 4f transitions of Eu
3+
appeared under irradiation with 530 nm light or X-rays. Among the samples, the highest emission intensity in the photoluminescence and X-ray-induced scintillation spectra was obtained for the glass. Furthermore, typical photoluminescence and scintillation decay time constants originating from the 4f → 4f transitions of Eu
3+
were obtained for the glass and glass ceramics. The afterglow level of the glass was comparable to that of the glass ceramics.
Polymer nanocomposites with engineered electrical properties can be made by tuning the fabrication method, processing conditions and filler’s geometric and physical properties. This work focuses on ...investigating the effect of filler’s geometry (aspect ratio and shape), intrinsic electrical conductivity, alignment and dispersion within the polymer, and polymer crystallinity, on the percolation threshold and electrical conductivity of polypropylene based nanocomposites. The conductive reinforcements used are exfoliated graphite nanoplatelets, carbon black, vapor grown carbon fibers and polyacrylonitrile carbon fibers. The composites are made using melt mixing followed by injection molding. A coating method is also employed to improve the nanofiller’s dispersion within the polymer and compression molding is used to alter the nanofiller’s alignment.
Induced pluripotent stem cells (iPSCs) are novel stem cells derived from adult mouse and human tissues by reprogramming. Elucidation of mechanisms and exploration of efficient methods for their ...differentiation to functional cardiomyocytes are essential for developing cardiac cell models and future regenerative therapies. We previously established a novel mouse embryonic stem cell (ESC) and iPSC differentiation system in which cardiovascular cells can be systematically induced from Flk1(+) common progenitor cells, and identified highly cardiogenic progenitors as Flk1(+)/CXCR4(+)/VE-cadherin(-) (FCV) cells. We have also reported that cyclosporin-A (CSA) drastically increases FCV progenitor and cardiomyocyte induction from mouse ESCs. Here, we combined these technologies and extended them to mouse and human iPSCs. Co-culture of purified mouse iPSC-derived Flk1(+) cells with OP9 stroma cells induced cardiomyocyte differentiation whilst addition of CSA to Flk1(+) cells dramatically increased both cardiomyocyte and FCV progenitor cell differentiation. Spontaneously beating colonies were obtained from human iPSCs by co-culture with END-2 visceral endoderm-like cells. Appearance of beating colonies from human iPSCs was increased approximately 4.3 times by addition of CSA at mesoderm stage. CSA-expanded human iPSC-derived cardiomyocytes showed various cardiac marker expressions, synchronized calcium transients, cardiomyocyte-like action potentials, pharmacological reactions, and ultra-structural features as cardiomyocytes. These results provide a technological basis to obtain functional cardiomyocytes from iPSCs.
Nd-doped CaWO4 single crystals with dopant concentrations of 0.1, 0.5, and 1% were synthesized by the floating zone method. The transmission, photoluminescence, and scintillation properties were ...evaluated from ultraviolet to near-infrared (NIR) ranges. An emission peak due to transitions of the host was observed at 400 nm, and several sharp peaks originating from Nd3+ 4f–4f transitions were confirmed at 900, 1060, and 1300 nm. The quantum yields of 0.1, 0.5, and 1% Nd-doped samples were 70.7, 79.5, and 61.2%, respectively, when monitored, and excited wavelengths were 750–1500 nm and 590 nm. Decay times consistent with typical Nd3+ transitions were obtained when NIR ranges were monitored. Additionally, the energy transfer between the host and Nd3+ occurred according to the decay measurement. The relationship between X-ray irradiated dose rate and intensity in the range of NIR was investigated by combining the crystals with an InGaAs-photodiode. The lowest detectable dose rate retaining the linearity of the present crystals was 0.3–0.06 Gy/h.
Photoluminescence, scintillation, and thermoluminescence characteristics of the Tb3+-activated gallate glasses (20K2O–(11-x/2)La2O3–69Ga2O3–x/2Tb4O7, x = 0.1–1.0) were investigated. The ...Tb3+-activated gallate glasses exhibited photoluminescence with some peaks at approximately 490, 540, 595, and 625 nm that were attributable to the 4f→4f transition of Tb3+. These peaks also appeared under X-ray radiation, and the x = 1.0 gallate glass showed the highest intensity. Moreover, a broad thermoluminescence glow peak appeared at 90 °C, and the thermoluminescence peak intensity decreased with increasing the Tb concentration. A complimentary relation between the scintillation and thermoluminescence intensity was observed.
•Luminescence properties of the Tb-doped gallate glasses were investigated.•The Tb-doped gallate glasses showed scintillation due to the 4f.→4f transitions of Tb3+.•A broad thermoluminescence glow peak appeared at 90 °C from the Tb-doped gallate glasses.
A cardioprotective response that alters ventricular contractility or promotes cardiomyocyte enlargement occurs with increased workload in conditions such as hypertension. When that response is ...excessive, pathological cardiac remodelling occurs, which can progress to heart failure, a leading cause of death worldwide. Mechanisms underlying this response are not fully understood. Here, we report that expression of angiopoietin-like protein 2 (ANGPTL2) increases in pathologically-remodeled hearts of mice and humans, while decreased cardiac ANGPTL2 expression occurs in physiological cardiac remodelling induced by endurance training in mice. Mice overexpressing ANGPTL2 in heart show cardiac dysfunction caused by both inactivation of AKT and sarco(endo)plasmic reticulum Ca
-ATPase (SERCA)2a signalling and decreased myocardial energy metabolism. Conversely, Angptl2 knockout mice exhibit increased left ventricular contractility and upregulated AKT-SERCA2a signalling and energy metabolism. Finally, ANGPTL2-knockdown in mice subjected to pressure overload ameliorates cardiac dysfunction. Overall, these studies suggest that therapeutic ANGPTL2 suppression could antagonize development of heart failure.
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