Silicon photonics: beating the bottleneck

The use of cascaded nonlinear silicon waveguides that function as 'time lenses' is providing new opportunities for generating and measuring ultrafast optical waveforms

Hypoxia inhibits the migratory capacity of human monocyte-derived dendritic cells

Hypoxia, a prominent characteristic of inflammatory tissue lesions and solid tumour microenvironments, is a crucial stimulus capable of modulating the expression of specific genes involved in leucocyte recruitment. Although studies have shown that hypoxia can affect leucocyte migration by influencing the expression of migration-related genes, such as matrix metalloproteinases (MMP) and their endogenous tissue inhibitors of matrix metalloproteinases (TIMP), it remains unclear whether hypoxia can affect the migration of dendritic cells (DC). In this study, we showed that human monocyte-derived DC under hypoxic conditions in a transwell system have significantly reduced migratory capacity compared to normoxic controls. A moderate phenotypic change of hypoxic DC was observed. In hypoxic DC, we detected a twofold increase in TIMP-1 transcript levels, and downregulated expression of MMP-9 and membrane type 1-MMP genes by threefold and 17-fold, respectively. Our results suggest that hypoxia may inhibit DC migratory activity by regulating the balance between MMP and TIMP gene expression. © 2005 Australasian Society for Immunology Inc.link_to_subscribed_fulltex

Ghost Imaging in the Time Domain

International audienceGhost imaging is a novel technique that produces the image of an object by correlating the intensity of two light beams, neither of which independently carries information about the shape of the object1, 2. Ghost imaging has opened up new perspectives to obtain highly resolved images3, even in the presence of noise and turbulence4. Here, by exploiting the duality between light propagation in space and time5, we demonstrate the temporal analogue of ghost imaging. We use a conventional fast detector that does not see the temporal ‘object’ to be characterized and a slow integrating ‘bucket’ detector that does see the object but without resolving its temporal structure. Our experiments achieve temporal resolution at the picosecond level and are insensitive to the temporal distortion that may occur after the object. The approach is scalable, can be integrated on-chip, and offers great promise for dynamic imaging of ultrafast waveforms