Ultra-broadband two-pump optical parametric amplifier in tellurite waveguides with engineered dispersion

The capacity of communication networks may be significantly improved by simply enhancing the optical amplifier bandwidth. This paper presents a numerical investigation of an ultra-broadband, low-ripple, two-pump-optical parametric amplifier (2P-OPA) that employs a tellurite glass buried-channel type nano-waveguide as nonlinear medium. The nano-waveguide was designed as a 25-cm-long Archimedean spiral that occupies a footprint of only similar to 2.5 mm(2), with a similar to 0.7 mu m(2) effective cross section. Its zero-dispersion wavelength is similar to 1550 nm, the nonlinear coefficient is similar to 3000 W-1 km(-1), and the attenuation coefficient is similar to 0.5 dB/m (1100 to 1900 nm). Simulations suggest a 2P-OPA based on such waveguide will be able to amplify 243 QPSK input channels modulated at 56 Gbps over 102 nm bandwidth, over metropolitan area network scales25442684283CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP574017/2008-9; 311137/2014-8; 311870/2014-72008/57857-

Early Fibrillin-1 Assembly Monitored through a Modifiable Recombinant Cell Approach

Fibrillin proteins constitute the backbone of extracellular macromolecular microfibrils. Mutations in fibrillins cause heritable connective tissue disorders, including Marfan syndrome, dominant Weill-Marchesani syndrome, and stiff skin syndrome. Fibronectin provides a critical scaffold for microfibril assembly in cell culture models. Full length recombinant fibrillin-1 was expressed by HEK 293 cells, which deposited the secreted protein in a punctate pattern on the cell surface. Co-cultured fibroblasts consistently triggered assembly of recombinant fibrillin-1, which was dependent on a fibronectin network formed by the fibroblasts. Deposition of recombinant fibrillin-1 on fibronectin fibers occurred first in discrete packages that subsequently extended along fibronectin fibers. Mutant fibrillin-1 harboring either a cysteine 204 to serine mutation or a RGD to RGA mutation which prevents integrin binding, did not affect fibrillin-1 assembly. In conclusion, we developed a modifiable recombinant full-length fibrillin-1 assembly system that allows for rapid analysis of critical roles in fibrillin assembly and functionality. This system can be used to study the contributions of specific residues, domains or regions of fibrillin-1 to the biogenesis and functionality of microfibrils. It provides also a method to evaluate disease-causing mutations, and to produce microfibril-containing matrices for tissue engineering applications for example in designing novel vascular grafts or stents