Multi-wavelength continuous-wave laser operation of Yb:Ca3Gd2(BO3)(4) disordered crystal
OPTICAL MATERIALS
Authors: Xu, Jin-Long; Tu, Chao-Yang; Wang, Yan; He, Jing-Liang
Abstract
The diode-pumped multi-wavelength continuous-wave laser operation of the disordered Yb:Ca3Gd2(BO3)(4) crystal was firstly investigated in this paper. The simultaneous emission wavelengths varied from 2 to 5 in the range from 1045.4 to 1063.6 nm with the change of the absorbed pump power and crystal length. An output power of 1.4 W was obtained with four-wavelength emission, corresponding to an optical-optical slope efficiency of 23.7%. Five-wavelength emission at 1049.4, 1051.3, 1053.4, 1055.6 and 1057.4 nm was realized under the output power of 1.0 W. The absorption behavior of Yb:Ca3Gd2(BO3)(4) have also been measured. (C) 2011 Elsevier B.V. All rights reserved.
Abnormal epigenetic changes during differentiation of human skeletal muscle stem cells from obese subjects
BMC MEDICINE
Authors: Davegardh, Cajsa; Broholm, Christa; Perfilyev, Alexander; Henriksen, Tora; Garcia-Calzon, Sonia; Peijs, Lone; Hansen, Ninna Schioler; Volkov, Petr; Kjobsted, Rasmus; Wojtaszewski, Jorgen F. P.; Pedersen, Maria; Pedersen, Bente Klarlund; Ballak, Dov B.; Dinarello, Charles A.; Heinhuis, Bas; Joosten, Leo A. B.; Nilsson, Emma; Vaag, Allan; Scheele, Camilla; Ling, Charlotte
Abstract
Background: Human skeletal muscle stem cells are important for muscle regeneration. However, the combined genome-wide DNA methylation and expression changes taking place during adult myogenesis have not been described in detail and novel myogenic factors may be discovered. Additionally, obesity is associated with low relative muscle mass and diminished metabolism. Epigenetic alterations taking place during myogenesis might contribute to these defects. Methods: We used Infinium HumanMethylation450 BeadChip Kit (Illumina) and HumanHT-12 Expression BeadChip (Illumina) to analyze genome-wide DNA methylation and transcription before versus after differentiation of primary human myoblasts from 14 non-obese and 14 obese individuals. Functional follow-up experiments were performed using siRNA mediated gene silencing in primary human myoblasts and a transgenic mouse model. Results: We observed genome-wide changes in DNA methylation and expression patterns during differentiation of primary human muscle stem cells (myoblasts). We identified epigenetic and transcriptional changes of myogenic transcription factors (MYOD1, MYOG, MYF5, MYF6, PAX7, MEF2A, MEF2C, and MEF2D), cell cycle regulators, metabolic enzymes and genes previously not linked to myogenesis, including IL32, metallothioneins, and pregnancy-specific beta-1-glycoproteins. Functional studies demonstrated IL-32 as a novel target that regulates human myogenesis, insulin sensitivity and ATP levels in muscle cells. Furthermore, IL32 transgenic mice had reduced insulin response and muscle weight. Remarkably, approximately 3.7 times more methylation changes (147,161 versus 39,572) were observed during differentiation of myoblasts from obese versus non-obese subjects. In accordance, DNMT1 expression increased during myogenesis only in obese subjects. Interestingly, numerous genes implicated in metabolic diseases and epigenetic regulation showed differential methylation and expression during differentiation only in obese subjects. Conclusions: Our study identifies IL-32 as a novel myogenic regulator, provides a comprehensive map of the dynamic epigenome during differentiation of human muscle stem cells and reveals abnormal epigenetic changes in obesity.