Integrated C-band erbium-doped fiber amplifier and dispersion compensation module with negligible pump power penalty.

Conventional dispersion compensation requires erbium-doped fiber amplifiers with high pump power to compensate for excess losses introduced by the dispersion-compensating fiber. We report and demonstrate an optimized single-pump amplifier configuration with a pump power penalty of less than 5% when integrated with a fiber Bragg grating dispersion compensator. The system is capable of compensating 100 km of G.

Advanced imaging with dynamic focus and extended depth using integrated FR4 platform.

A two-degrees-of-freedom scanned beam imaging system with large dynamic range and dynamic focusing is demonstrated. The laser diode, photo-detector and the optical components are integrated on a moving platform that is made of FR4 (Flame-Retardant 4), a common polymeric substrate used in printed circuit boards. A scan angle of 52 degrees is demonstrated at 60 Hz resonant frequency while the laser is moved 250 um in the out-of-plane direction to achieve dynamic focusing.

Matrix metalloproteinases and their inhibitors in bone: an overview of regulation and functions.

Matrix metalloproteinases (MMPs), a family of Zn2+-dependent endopeptidases, mediate different physiological processes by digesting components of the extracellular matrix. Nevertheless, overexpression of MMPs is implicated in the pathogenesis of various diseases. Different MMPs and tissue inhibitors of MMPs (TIMPs) are expressed in bone cells, and their biosynthesis is regulated by local and systemic hormones and factors.

Bone morphogenetic protein-2 suppresses collagenase-3 promoter activity in osteoblasts through a runt domain factor 2 binding site.

Transforming growth factor-beta (TGFbeta) superfamily of growth factors, which include bone morphogenetic proteins (BMPs), have multiple effects in osteoblasts. In this study, we examined the regulation of collagenase-3 promoter activity by BMP-2 in osteoblast-enriched (Ob) cells from fetal rat calvariae. BMP-2 suppressed the activity of a -2 kb collagenase-3 promoter/luciferase recombinant in a time- and dose-dependent manner.

Effects of activated T cells on osteoclastogenesis depend on how they are activated.

Introduction: Activated T cells are emerging as important regulators of osteoclast function in inflammatory diseases. Both pro- and anti-resorptive properties have been described. We reasoned that this reported variability of the effects of T cells on osteoclast formation depends on how T cells are activated in vitro.

Transcriptional regulation of collagenase-3 by interleukin-1 alpha in osteoblasts.

Interleukin-1 (IL-1)alpha is an autocrine/paracrine agent of the skeletal tissue and it regulates bone remodeling. Collagenase-3 or matrix metalloproteinase (MMP)-13 is expressed in osteoblasts and its expression is modulated by several cytokines including IL-1alpha. Because the molecular mechanism of increased synthesis of collagenase-3 in bone cells by IL-1alpha is not known, we investigated if collagenase-3 expression by IL-1alpha in osteoblasts is mediated by transcriptional or post-transcriptional mechanisms.

Effects of serum from children with newly diagnosed Crohn disease on primary cultures of rat osteoblasts.

Objectives: We propose that Crohn disease (CD) decreases bone formation via circulating inflammatory mediators. We therefore examined the effects of serum from newly diagnosed, untreated children with CD on osteoblasts in culture and the role of interleukin-6 (IL-6), a cytokine present in excess in active CD that also has direct effects on bone.

Methods: Bone mineral density was measured by dual x-ray absorptiometry.