Sliding and healing of frictional interfaces that appear stationary.

Frictional interfaces are found in systems ranging from biological joints to earthquake faults. When and how these interfaces slide is a fundamental problem in geosciences and engineering. It is believed that there exists a threshold shear force, called static friction, below which the interface is stationary, despite many studies suggesting that this concept is outdated.

Microvesicles derived from dermal myofibroblasts modify the integrity of the blood and lymphatic barriers using distinct endocytosis pathways.

Microvesicles (MVs) are a subtype of extracellular vesicles that can transfer biological information from their producer cells to target cells. This communication can in turn affect both normal and pathological processes. Mounting evidence has revealed that dermal wound myofibroblasts (Wmyo) produce MVs, which can transfer biomolecules impacting receptor cells such as human dermal microvascular endothelial cells (HDMECs).

The diffusion of normal skin wound myofibroblast-derived microvesicles differs according to matrix composition.

Microvesicles (MVs) are a subtype of extracellular vesicles that can transfer biological information over long distances, affecting normal and pathological processes including skin wound healing. However, the diffusion of MVs into tissues can be impeded by the extracellular matrix (ECM). We investigated the diffusion of dermal wound myofibroblast-derived MVs into the ECM by using hydrogels composed of different ECM molecules such as fibrin, type III collagen and type I collagen that are present during the healing process.

Modeling extended L-band fiber amplifiers using neural networks trained on experimental data.

Producing high performance amplifiers requires accurate numerical models. As the optimization space is large, computationally efficient models are of great value. Parameter-based models for L-band amplifiers have accuracy limited by difficulty in estimating the Giles-parameter.

Towards REPO nanocrystal-doped optical fibers for distributed sensing applications.

Rayleigh scattering enhanced nanoparticle-doped optical fibers, for distributed sensing applications, is a new technology that offers unique advantages to optical fiber community. However, the existing fabrication technology, based on in situ grown alkaline earth nanoparticles, is restricted to few compositions and exhibit a great dependence on many experimental conditions. Moreover, there is still several uncertainties about the effect of drawing process on the nanoparticle characteristics and its influence on the scattering enhancement and the induced optical loss.

An in vitro autologous, vascularized, and immunocompetent Tissue Engineered Skin model obtained by the self-assembled approach.

A complete in vitro skin model, containing resident cell types is needed to understand physiology and to consider the role of immune and endothelial cells in dermal drug testing. In this study, a cell extraction technique was developed to isolate resident skin cells from the same human donor while preserving the immune and endothelial cells. Then those cells were used to reconstruct an autologous, vascularized, and immunocompetent Tissue-Engineered Skin model, aviTES.

The role of tungsten oxide in Er-doped bismuth-germanate glasses for optical amplification in L-band.

A series of novel Er-doped bismuth-germanate glasses containing different tungsten concentrations with a molar composition of 97.5[(75 - x)GeO-25BiO-(x)WO]-2SbO-0.5ErO (x = 5, 10, 15, 20, and 25 mol%) were fabricated.

Optimization criteria and design of few-mode Erbium-doped fibers for cladding-pumped amplifiers.

We propose a novel optimization method that combines two design criteria to reduce the differential modal gain (DMG) in few-mode cladding-pumped erbium-doped fiber amplifiers (FM-EDFAs). In addition to the standard criterion that considers the mode intensity and dopant profile overlap, we introduce a second criterion that ensures that all doped regions have the same saturation behavior. With these two criteria, we define a figure-of-merit (FOM) that allows the design of FM-EDFAs with low DMG without high computational cost.

Large area Bragg grating for pump recycling in cladding-pumped multicore erbium-doped fiber amplifiers.

We demonstrate for the first time that a Bragg grating can be written over a large area inside the cladding of a multicore erbium-doped fiber amplifier to increase the power conversion efficiency (PCE) by recycling the output pump power. Our results indicate that a Bragg grating covering ∼25% of the cladding area allows us to recycle 19% of the output pump power which leads to a relative increase of the PCE by 16% for an input pump power of 10.6 W in the specific case of an eight-core erbium-doped fiber with a length of 20.

Silicon-coupled tantalum pentoxide microresonators with broadband low thermo-optic coefficient.

Stable microresonators are important integrated photonics components but are difficult to achieve on silicon-on-insulator due to silicon intrinsic properties. In this work, we demonstrate broadband thermally stable tantalum pentoxide microresonators directly coupled to silicon waveguides using a micro-trench co-integration method. The method combines in-foundry silicon processing with a single step backend thin-film deposition.

Silicon subwavelength grating waveguides with high-index chalcogenide glass cladding.

Silicon subwavelength grating waveguides enable flexible design in integrated photonics through nano-scale refractive index engineering. Here, we explore the possibility of combining silicon subwavelength gratings waveguides with a high-index chalcogenide glass as a top cladding, thus modifying the waveguiding behavior and opening a new design axis for these structures. A detailed investigation of the heterogeneous SWG waveguide with high-index cladding is presented based on analytical and numerical simulations.

Engineering nanoparticle features to tune Rayleigh scattering in nanoparticles-doped optical fibers.

Rayleigh scattering enhanced nanoparticles-doped optical fibers are highly promising for distributed sensing applications, however, the high optical losses induced by that scattering enhancement restrict considerably their sensing distance to few meters. Fabrication of long-range distributed optical fiber sensors based on this technology remains a major challenge in optical fiber community. In this work, it is reported the fabrication of low-loss Ca-based nanoparticles doped silica fibers with tunable Rayleigh scattering for long-range distributed sensing.

GPR43 regulates sodium butyrate-induced angiogenesis and matrix remodeling.

Butyrate is a short-chain fatty acid (SCFA) derived from microbiota and is involved in a range of cell processes in a concentration-dependent manner. Low concentrations of sodium butyrate (NaBu) were shown to be proangiogenic. However, the mechanisms associated with these effects are not yet fully known.

Fuseless side-pump combiner for efficient fluoride-based double-clad fiber pumping.

We report a novel technique for side-pumping fluoride-based double-clad fibers, allowing a record coupling efficiency of 93% and a maximum power handling near 100 W at 981 nm. Our simple technique is based on wrapping a silica taper around a fluoride fiber and, therefore, does not require any complex fusion between these two dissimilar fibers. Under passive cooling, pump combiners made of undoped and erbium-doped fluoride fibers were successfully operated during several hours at respective incident powers of 91 and 44 W.

Shedding of proangiogenic microvesicles from hypertrophic scar myofibroblasts.

Hypertrophic scars are a common complication of burn injuries and represent a major challenge in terms of prevention and treatment. These scars are characterized by a supraphysiological vascular density and by the presence of pathological myofibroblasts (Hmyos) displaying a low apoptosis propensity. However, the nature of the association between these two hallmarks of hypertrophic scarring remains largely unexplored.

Real-time gap-free dynamic waveform spectral analysis with nanosecond resolutions through analog signal processing.

Real-time tracking of a waveform frequency content is essential for detection and analysis of fast rare events in communications, radar, radio astronomy, spectroscopy, sensing etc. This requires a method that can provide real-time spectrum analysis (RT-SA) of high-speed waveforms in a continuous and gap-free fashion. Digital signal processing is inefficient to perform RT-SA over instantaneous frequency bandwidths above the sub-GHz range and/or to track spectral changes faster than a few microseconds.

PLGF-1 contained in normal wound myofibroblast-derived microvesicles stimulated collagen production by dermal fibroblasts.

During the last stages of wound healing, myofibroblasts differentiate mainly from fibroblasts. Myofibroblasts from normal skin wounds (Wmyo) can communicate with its surrounding using secreted factors. They also have the capacity to produce microvesicles (MVs), a type of extracellular vesicles, as mediators of intercellular communication.

Etchless chalcogenide microresonators monolithically coupled to silicon photonic waveguides.

Integration of chalcogenide waveguides in silicon photonics can mitigate the prohibitive nonlinear losses of silicon while leveraging the mature complementary metal-oxide-semiconductor (CMOS)-compatible nanophotonic fabrication process. In this work, we demonstrate, for the first time, to the best of our knowledge, a method of integrating high- chalcogenides microring resonators onto the silicon photonics platform without post-process etching. The method uses micro-trench filling and a novel thermal dewetting technique to form low-loss chalcogenide strip waveguides.

Highly elliptical core fiber with stress-induced birefringence for mode multiplexing.

We report the polarization-maintaining properties of a highly elliptical core fiber surrounded by a trench that was designed to optimize the modal effective indices and bending loss for a total of five spatial modes (10 channels). In addition to the asymmetric core structure, the birefringence of the fiber is increased by the thermal stress introduced during the fabrication. The results show a modal birefringence larger than 10 for all guided spatial modes.

α-2-Macroglobulin induces the shedding of microvesicles from cutaneous wound myofibroblasts.

Microvesicles (MVs) are recognized as an important class of cell-to-cell messengers. Although the properties of MVs are increasingly documented, the mechanisms regulating MV biogenesis remain debated. Myofibroblasts are a key cellular component of wound healing and have been shown to produce MVs upon stimulation with serum.

Demonstration of an erbium-doped fiber with annular doping for low gain compression in cladding-pumped amplifiers.

We present the design and characterization of a cladding-pumped amplifier with erbium doping located in an annular region near the core. This erbium-doped fiber is proposed to reduce gain saturation, leading to smaller gain compression when compared to uniform core doping. Through numerical simulations, we first compare the performance of three fibers with different erbium doping profiles in the core or the cladding.

Integrated flexible-grid WDM transmitter using an optical frequency comb in microring modulators.

Advanced optical interconnects require high-speed links, which can be achieved by combining high channel rates with wavelength-division multiplexing (WDM). We report a multi-channel transmitter using cascaded microring modulators (MRMs) in silicon photonics. One MRM works as a flexible-grid optical comb generator, while the others work as channel modulators.

Subwavelength-grating contradirectional couplers for large stopband filters.

Manipulating the coupling coefficient at subwavelength scales provides an additional degree of freedom in designing integrated Bragg gratings. We demonstrate asymmetric contradirectional couplers (contra-DCs) using sidewall-corrugated subwavelength grating (SWG) waveguides for broadband add-drop Bragg filters. We show that a SWG can effectively increase the overlap of coupled modes and thus the photonic band gap.