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Ceramic phosphor plates of (Y,Gd) 3 Al 5 O 12 :Ce (or YAG:Ce) are considered better wavelength converters for high power light-emitting-diode (LED) and laser-diode (LD) lighting applications due to their significantly better thermal conductivities and heat resistance as compared to phosphor powder/epoxy films. In this work, we have measured the thermal conductivities of Ce3+ doped (Y 1-x Gd x) 3 Al 5 O 15 (x from 0 to 1) ceramic phosphor plates at temperatures of 296 K and 473 K. As temperature increases from 296 K to 473 K, the thermal conductivities decrease by about 37%. They are also strongly dependent on the concentration of Gd3+, or x in (Y 1-x Gd x) 3 Al 5 O 15. They decrease with x increasing first, reaching a minimum at x between 0.4 and 0.6, and then increase with x as it continues to increase to 1. The dependence of the thermal conductivity on Gd3+ concentration is not linear but a "U" type, suggesting that substitution of Y3+ with Gd3+ may cause extra phonon scattering, resulting in lower thermal conductivities as compared to their intrinsic values. A quantitative relationship between thermal conductivity and Gd3+ concentration is derived for this material system. • Thermal conductivities of (Y 1-x Gd x) 3 Al 5 O 12 :Ce have been measured at 296 K and 473 K. • Substitution of Y3+ with Gd3+ changes thermal conductivities of (Y,Gd) 3 Al 5 O 12 :Ce. • Quantitative relationship of thermal conductivity vs Gd concentration is established. [ABSTRACT FROM AUTHOR]

Technological advances in glaucoma have challenged the traditional treatment paradigm. Historically incisional surgery has been used in cases of advanced disease and/or uncontrolled intraocular pressures resistant to medical or laser interventions. More recently, perhaps due to advancements in imaging, surgery has been suggested to be beneficial earlier in the treatment paradigm. Despite these trends, surgical manipulation of the tissues and unpredictability of wound healing continue to result in surgical failure. Magnesium is an essential element for human body and plays a critically important role in maintaining the functional and structural integrity of several tissues, including the eye. Due to several of its advantageous properties such as non-toxicity, biodegradability, and high biological compatibility, magnesium alloy has attracted great attention as a novel biomaterial. Biodegradable cardiovascular stents made of magnesium alloy have already been introduced into clinical practice. The purpose of this review is to determine if bioabsorbable magnesium alloys can be utilized as a promising candidate for the development of a new generation of glaucoma surgical assistive devices.

The discovery of buckminsterfullerene C(60) opened up a new scientific area and stimulated the development of nanoscience and nanotechnology directly. Fullerene science has since emerged to include fullerenes, endohedral fullerenes (mainly metallofullerenes), exofullerenes, and carbon nanotubes as well. Herein, we look back at the development of fullerene science from the perspective of epistemology by highlighting the proposed main rules or criteria for understanding and predicting the structures and stability of fullerene-based compounds. We also point out that a rule or criterion may contribute significantly to the corresponding discipline and suggest that two unsolved issues in fullerene science are the addition patterns of fullerene derivatives and the structures and stability of nonclassical fullerenes., (Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)