Chromatic dispersion compensation and coherent Direct-Sequence OCDMA operation on a single super structured FBG

This paper was published in OPTICS EXPRESS and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/10.1364/OE.20.013966 . Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under lawWe have proposed, fabricated and demonstrated experimentally a set of Coherent Direct Sequence-OCDMA en/decoders based on Super Structured Fiber Bragg Gratings (SSFBGs) which are able to compensate the fiber chromatic dispersion at the same time that they perform the en/decoding task. The proposed devices avoid the use of additional dispersion compensation stages reducing system complexity and losses. This performance was evaluated for 5.4, 11.4 and 16.8 km of SSMF. The twofold performance was verified in Low Reflectivity regime employing only one GVD compensating device at decoder or sharing out the function between encoder and decoder devices. Shared functionality requires shorter SSFBGs designs and also provides added flexibility to the optical network design. Moreover, dispersion compensated en/decoders were also designed into the High Reflectivity regime employing synthesis methods achieving more than 9 dB reduction of insertion loss for each device. © 2012 Optical Society of America.This work was supported by the Spanish Government project TEC 2009-12169, and the Valencian Government under the projects ACOMP/2012/023 and FPA/2012/009.Baños López, R.; Pastor Abellán, D.; Amaya Ocampo, WA.; García Muñoz, V. (2012). Chromatic dispersion compensation and coherent Direct-Sequence OCDMA operation on a single super structured FBG. Optics Express. 20(13):13966-13976. doi:10.1364/OE.20.013966S13966139762013Kitayama, K., Xu Wang, & Naoya Wada. (2006). OCDMA over WDM PON-solution path to gigabit-symmetric FTTH. Journal of Lightwave Technology, 24(4), 1654-1662. doi:10.1109/jlt.2006.871030Xu Wang, & Naoya Wada. (2006). Experimental demonstration of OCDMA traffic over optical packet switching network with hybrid PLC and SSFBG en/decoders. Journal of Lightwave Technology, 24(8), 3012-3020. doi:10.1109/jlt.2006.878287Sotobayashi, H., Chujo, W., & Kitayama, K. (2002). Transparent virtual optical code/wavelength path network. IEEE Journal of Selected Topics in Quantum Electronics, 8(3), 699-704. doi:10.1109/jstqe.2002.1016375Pastor, D., Amaya, W., García-Olcina, R., & Sales, S. (2007). Coherent direct sequence optical code multiple access encoding-decoding efficiency versus wavelength detuning. Optics Letters, 32(13), 1896. doi:10.1364/ol.32.001896Wang, X., Matsushima, K., Nishiki, A., Wada, N., & Kitayama, K. (2004). High reflectivity superstructured FBG for coherent optical code generation and recognition. Optics Express, 12(22), 5457. doi:10.1364/opex.12.005457Pastor, D., Amaya, W., & Garcia-Olcina, R. (2007). Design of high reflectivity superstructured FBG for coherent OCDMA employing synthesis approach. Electronics Letters, 43(15), 824. doi:10.1049/el:20071171Skaar, J., Ligang Wang, & Erdogan, T. (2001). On the synthesis of fiber Bragg gratings by layer peeling. IEEE Journal of Quantum Electronics, 37(2), 165-173. doi:10.1109/3.903065Amaya, W., Pastor, D., Baños, R., & Garcia-Munoz, V. (2011). WDM-Coherent OCDMA over one single device based on short chip Super structured fiber Bragg gratings. Optics Express, 19(24), 24627. doi:10.1364/oe.19.024627Amaya, W., Pastor, D., & Capmany, J. (2008). Modeling of a Time-Spreading OCDMA System Including Nonperfect Time Gating, Optical Thresholding, and Fully Asynchronous Signal/Interference Overlapping. Journal of Lightwave Technology, 26(7), 768-776. doi:10.1109/jlt.2007.91520

WDM-Coherent OCDMA over one single device based on short chip Super structured fiber Bragg gratings

This paper was published in OPTICS EXPRESS and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/10.1364/OE.19.024627. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under lawWe theoretically propose and demonstrate experimentally a Coherent Direct Sequence OCDMA en/decoder for multi-channel WDM operation based on a single device. It presents a broadband spectral envelope and a periodic spectral pattern that can be employed for en/decoding multiple sub-bands simultaneously. Multi-channel operation is verified experimentally by means of Multi-Band Super Structured Fiber Bragg Gratings with binary phase encoded chips fabricated with 1mm inter-chip separation that provides 4x100 GHz ITU sub-band separation at 1.25 Gbps. The WDM-OCDMA system verification was carried out employing simultaneous encoding of four adjacent sub-bands and two different OCDMA codes. (C) 2011 Optical Society of AmericaWe would like to thank our reviewers for their thoughtful comments and suggestions. This work was supported by the Spanish Government project TEC 2009-12169, and the Valencian Government under the project ACOMP/2010/023.Amaya Ocampo, WA.; Pastor Abellán, D.; Baños López, R.; García Muñoz, V. (2011). WDM-Coherent OCDMA over one single device based on short chip Super structured fiber Bragg gratings. Optics Express. 19(24):24627-24637. https://doi.org/10.1364/OE.19.024627S24627246371924Green, P. E. (2002). Paving the last mile with glass. IEEE Spectrum, 39(12), 13-14. doi:10.1109/mspec.2002.1088446Kitayama, K., Xu Wang, & Naoya Wada. (2006). OCDMA over WDM PON-solution path to gigabit-symmetric FTTH. Journal of Lightwave Technology, 24(4), 1654-1662. doi:10.1109/jlt.2006.871030Amaya, W., Pastor, D., & Capmany, J. (2008). Modeling of a Time-Spreading OCDMA System Including Nonperfect Time Gating, Optical Thresholding, and Fully Asynchronous Signal/Interference Overlapping. Journal of Lightwave Technology, 26(7), 768-776. doi:10.1109/jlt.2007.915209Xu Wang, & Naoya Wada. (2006). Experimental demonstration of OCDMA traffic over optical packet switching network with hybrid PLC and SSFBG en/decoders. Journal of Lightwave Technology, 24(8), 3012-3020. doi:10.1109/jlt.2006.878287Matsushima, K., Wang, X., Kutsuzawa, S., Nishiki, A., Oshiba, S., Wada, N., & Kitayama, K. (2004). Experimental Demonstration of Performance Improvement of 127-Chip SSFBG En/Decoder Using Apodization Technique. IEEE Photonics Technology Letters, 16(9), 2192-2194. doi:10.1109/lpt.2004.831555Teh, P. C., Ibsen, M., Lee, J. H., Petropoulos, P., & Richardson, D. J. (2002). Demonstration of a four-channel WDM/OCDMA system using 255-chip 320-Gchip/s quarternary phase coding gratings. IEEE Photonics Technology Letters, 14(2), 227-229. doi:10.1109/68.980530Pastor, D., Amaya, W., García-Olcina, R., & Sales, S. (2007). Coherent direct sequence optical code multiple access encoding-decoding efficiency versus wavelength detuning. Optics Letters, 32(13), 1896. doi:10.1364/ol.32.00189

Ambra1 spatially regulates Src activity and Src/FAK-mediated cancer cell invasion via trafficking networks

Here, using mouse squamous cell carcinoma cells, we report a completely new function for the autophagy protein Ambra1 as the first described ‘spatial rheostat’ controlling the Src/FAK pathway. Ambra1 regulates the targeting of active phospho-Src away from focal adhesions into autophagic structures that cancer cells use to survive adhesion stress. Ambra1 binds to both FAK and Src in cancer cells. When FAK is present, Ambra1 is recruited to focal adhesions, promoting FAK-regulated cancer cell direction-sensing and invasion. However, when Ambra1 cannot bind to FAK, abnormally high levels of phospho-Src and phospho-FAK accumulate at focal adhesions, positively regulating adhesion and invasive migration. Spatial control of active Src requires the trafficking proteins Dynactin one and IFITM3, which we identified as Ambra1 binding partners by interaction proteomics. We conclude that Ambra1 is a core component of an intracellular trafficking network linked to tight spatial control of active Src and FAK levels, and so crucially regulates their cancer-associated biological outputs

ZMYND10 functions in a chaperone relay during axonemal dynein assembly

Molecular chaperones promote the folding and macromolecular assembly of a diverse set of ‘client’ proteins. How ubiquitous chaperone machineries direct their activities towards specific sets of substrates is unclear. Through the use of mouse genetics, imaging and quantitative proteomics we uncover that ZMYND10 is a novel co-chaperone that confers specificity for the FKBP8-HSP90 chaperone complex towards axonemal dynein clients required for cilia motility. Loss of ZMYND10 perturbs the chaperoning of axonemal dynein heavy chains, triggering broader degradation of dynein motor subunits. We show that pharmacological inhibition of FKBP8 phenocopies dynein motor instability associated with the loss of ZMYND10 in airway cells and that human disease-causing variants of ZMYND10 disrupt its ability to act as an FKBP8-HSP90 co-chaperone. Our study indicates that primary ciliary dyskinesia (PCD), caused by mutations in dynein assembly factors disrupting cytoplasmic pre-assembly of axonemal dynein motors, should be considered a cell-type specific protein-misfolding disease

Rapamycin Regulates Autophagy and Cell Adhesion in Induced Pluripotent Stem Cells

Background Cellular reprogramming is a stressful process, which requires cells to engulf somatic features and produce and maintain stemness machineries. Autophagy is a process to degrade unwanted proteins and is required for the derivation of induced pluripotent stem cells (iPSCs). However, the role of autophagy during iPSC maintenance remains undefined. Methods Human iPSCs were investigated by microscopy, immunofluorescence, and immunoblotting to detect autophagy machinery. Cells were treated with rapamycin to activate autophagy and with bafilomycin to block autophagy during iPSC maintenance. High concentrations of rapamycin treatment unexpectedly resulted in spontaneous formation of round floating spheres of uniform size, which were analyzed for differentiation into three germ layers. Mass spectrometry was deployed to reveal altered protein expression and pathways associated with rapamycin treatment. Results We demonstrate that human iPSCs express high basal levels of autophagy, including key components of APMKα, ULK1/2, BECLIN-1, ATG13, ATG101, ATG12, ATG3, ATG5, and LC3B. Block of autophagy by bafilomycin induces iPSC death and rapamycin attenuates the bafilomycin effect. Rapamycin treatment upregulates autophagy in iPSCs in a dose/time-dependent manner. High concentration of rapamycin reduces NANOG expression and induces spontaneous formation of round and uniformly sized embryoid bodies (EBs) with accelerated differentiation into three germ layers. Mass spectrometry analysis identifies actin cytoskeleton and adherens junctions as the major targets of rapamycin in mediating iPSC detachment and differentiation. Conclusions High levels of basal autophagy activity are present during iPSC derivation and maintenance. Rapamycin alters expression of actin cytoskeleton and adherens junctions, induces uniform EB formation, and accelerates differentiation. IPSCs are sensitive to enzyme dissociation and require a lengthy differentiation time. The shape and size of EBs also play a role in the heterogeneity of end cell products. This research therefore highlights the potential of rapamycin in producing uniform EBs and in shortening iPSC differentiation duration

VGLL3 operates via TEAD1, TEAD3 and TEAD4 to influence myogenesis in skeletal muscle

© 2019. Published by The Company of Biologists Ltd.Peer reviewedPublisher PD

HEATR2 Plays a Conserved Role in Assembly of the Ciliary Motile Apparatus

Cilia are highly conserved microtubule-based structures that perform a variety of sensory and motility functions during development and adult homeostasis. In humans, defects specifically affecting motile cilia lead to chronic airway infections, infertility and laterality defects in the genetically heterogeneous disorder Primary Ciliary Dyskinesia (PCD). Using the comparatively simple Drosophila system, in which mechanosensory neurons possess modified motile cilia, we employed a recently elucidated cilia transcriptional RFX-FOX code to identify novel PCD candidate genes. Here, we report characterization of CG31320/HEATR2, which plays a conserved critical role in forming the axonemal dynein arms required for ciliary motility in both flies and humans. Inner and outer arm dyneins are absent from axonemes of CG31320 mutant flies and from PCD individuals with a novel splice-acceptor HEATR2 mutation. Functional conservation of closely arranged RFX-FOX binding sites upstream of HEATR2 orthologues may drive higher cytoplasmic expression of HEATR2 during early motile ciliogenesis. Immunoprecipitation reveals HEATR2 interacts with DNAI2, but not HSP70 or HSP90, distinguishing it from the client/chaperone functions described for other cytoplasmic proteins required for dynein arm assembly such as DNAAF1-4. These data implicate CG31320/HEATR2 in a growing intracellular pre-assembly and transport network that is necessary to deliver functional dynein machinery to the ciliary compartment for integration into the motile axoneme