A 2 kW, 8 GHz-Linewidth Yb-Doped Polarization-Maintained Fiber Laser with Quasi-Flat-Top Pseudo Random Binary Sequence Phase Modulation for SBS Suppression.

We demonstrated a narrow-linewidth high-power Yb-doped polarization-maintaining (PM) fiber laser with near-diffraction-limited beam. The laser system consisted of a phase-modulated single-frequency seed source and four-stage amplifiers in the master oscillator power amplifier configuration. A quasi-flat-top pseudo random binary sequence (PRBS) phase-modulated single-frequency laser with a linewidth of 8 GHz was injected into the amplifiers for suppressing stimulated Brillouin scattering. The quasi-flat-top PRBS signal was readily generated from the conventional PRBS signal. The maximum output power was 2.01 kW with polarization extinction ratio (PER) of ~15 dB. The beam quality (M2) was less than 1.3 over the power scaling range.

Glycolytic reprogramming is involved in tissue remodeling on chronic rhinosinusitis.

BACKGROUND: Glycolytic reprogramming is a key feature of chronic inflammatory disease. Extracellular matrix (ECM) produced by myofibroblasts plays an important role in tissue remodeling of nasal mucosa in chronic rhinosinusitis (CRS). This study aimed to determine whether glycolytic reprogramming contributes to myofibroblast differentiation and ECM production in nasal fibroblasts. METHODS: Primary nasal fibroblasts were isolated from the nasal mucosa of patients with CRS. Glycolytic reprogramming was assessed by measuring the extracellular acidification and oxygen consumption rates in nasal fibroblast, with and without transforming growth factor beta 1 (TGF-ß1) treatment. Expression of glycolytic enzymes and ECM components was measured by real-time polymerase chain reaction, western blotting, and immunocytochemical staining. Gene set enrichment analysis was performed using whole RNA-sequencing data of nasal mucosa of healthy donors and patients with CRS. RESULT: Glycolysis of nasal fibroblasts stimulated with TGF-B1 was upregulated along with glycolytic enzymes. Hypoxia-inducing factor (HIF)-1α was a high-level regulator of glycolysis, and increased HIF-1α expression promoted glycolysis of nasal fibroblasts, and inhibition of HIF-1α down-regulated myofibroblasts differentiation and ECM production. CONCLUSION: This study suggests that inhibition of the glycolytic enzyme and HIF-1α in nasal fibroblasts regulates myofibroblast differentiation and ECM generation associated with nasal mucosa remodeling.

Eosinophil-Derived Osteopontin Induces the Expression of Pro-Inflammatory Mediators and Stimulates Extracellular Matrix Production in Nasal Fibroblasts: The Role of Osteopontin in Eosinophilic Chronic Rhinosinusitis.

Background: Eosinophilic chronic rhinosinusitis (ECRS) is a subtype of chronic rhinosinusitis (CRS) and is a refractory or intractable disease. However, a reliable clinical marker or an effective treatment strategy has not yet been established. ECRS is accompanied by excessive eosinophil infiltration and Th2 inflammatory response, which is closely related to tissue remodeling in the upper airways. Objectives: We sought to investigate the effect of eosinophils on tissue remodeling in ECRS. The purpose of this study was to identify the effects of eosinophils on the expression of pro-inflammatory mediators and extracellular matrix (ECM) in nasal fibroblasts and the key mediators that stimulate them. Methods: Butyric acid was used to differentiate EOL-1 cells into eosinophils. We co-cultured differentiated EOL-1 cells and fibroblasts to measure the expression of pro-inflammatory mediators and ECM in fibroblasts. Among the cytokines secreted from the differentiated EOL-1 cells, factors that induced tissue remodeling of fibroblasts were identified. Results: Treatment with butyric acid (BA) differentiated EOL-1 cells into eosinophils. Differentiated EOL-1 cells induced fibroblasts to produce pro-inflammatory mediators, IL-6 and IL-8, and tissue remodeling factor, VEGF. It also induced myofibroblast differentiation and overexpression of ECM components. Differentiated EOL-1 cells overexpressed osteopontin (OPN), and recombinant OPN increased the expression of IL-6, IL-8, VEGF, and ECM components in nasal fibroblast. OPN was overexpressed in the nasal tissue of patients with ECRS and was associated with the severity of CRS. Conclusions: Eosinophil-derived OPN stimulated nasal fibroblasts and contributed to inflammation and tissue remodeling in ECRS. Moreover, the expression level of OPN was proportional to the severity of ECRS. Therefore, OPN regulation is a potential treatment for ECRS.

740-watt level optical tap coupler using side-polished large-mode-area double clad fibers for a high power fiber laser.

We fabricated a fiber-optic directional coupler based on evanescent field coupling between side-polished large mode area (LMA) double clad fibers (DCFs) for a high power fiber laser. The tapping ratio of the fabricated coupler was measured to be - 32 dB. The fundamental mode coupled in a core of the lower side-polished fiber (SPF) was transferred to the upper SPF without clad-mode coupling. Two SPFs were directly faced to increase an optical handling power up to 740 W. The tapping ratio of the coupler was constantly maintained at the applied laser output. The beam quality of the laser including the fabricated coupler was maintained to be 1.22, without mode distortion by the coupler.

Protein-Based Electronic Skin Akin to Biological Tissues.

Human skin provides an interface that transduces external stimuli into electrical signals for communication with the brain. There has been considerable effort to produce soft, flexible, and stretchable electronic skin (E-skin) devices. However, common polymers cannot imitate human skin perfectly due to their poor biocompatibility, biofunctionality, and permeability to many chemicals and biomolecules. Herein, we report on highly flexible, stretchable, conformal, molecule-permeable, and skin-adhering E-skins that combine a metallic nanowire (NW) network and silk protein hydrogel. The silk protein hydrogels offer high stretchability and stability under hydration through the addition of Ca2+ ions and glycerol. The NW electrodes exhibit stable operation when subjected to large deformations and hydration. Meanwhile, the hydrogel window provides water and biomolecules to the electrodes (communication between the environment and the electrode). These favorable characteristics allow the E-skin to be capable of sensing strain, electrochemical, and electrophysiological signals.

High-Contrast Infrared Absorption Spectroscopy via Mass-Produced Coaxial Zero-Mode Resonators with Sub-10 nm Gaps.

We present a wafer-scale array of resonant coaxial nanoapertures as a practical platform for surface-enhanced infrared absorption spectroscopy (SEIRA). Coaxial nanoapertures with sub-10 nm gaps are fabricated via photolithography, atomic layer deposition of a sacrificial Al2O3 layer to define the nanogaps, and planarization via glancing-angle ion milling. At the zeroth-order Fabry-Pérot resonance condition, our coaxial apertures act as a "zero-mode resonator (ZMR)", efficiently funneling as much as 34% of incident infrared (IR) light along 10 nm annular gaps. After removing Al2O3 in the gaps and inserting silk protein, we can couple the intense optical fields of the annular nanogap into the vibrational modes of protein molecules. From 7 nm gap ZMR devices coated with a 5 nm thick silk protein film, we observe high-contrast IR absorbance signals drastically suppressing 58% of the transmitted light and infer a strong IR absorption enhancement factor of 104∼105. These single nanometer gap ZMR devices can be mass-produced via batch processing and offer promising routes for broad applications of SEIRA.

Development and characterization of piezoelectrically actuated corner cube retroreflectors for applications in free-space optical sensor network.

In this paper, we report the development of an optical sensor network (OSN) based on piezoelectrically actuated corner cube retroreflectors (PA-CCRs). PA-CCRs were fabricated by microelectromechanical systems processes and assembled by aligning horizontally actuated mirrors and vertical side walls in a holder, which allows mass production. Fabricated PA-CCRs showed a tilting angle by more than 1.5 deg at 5 V bias voltage. A 3 dB cutoff frequency was measured to be in the range of 3.5 kHz. To show the feasilbility, an OSN was established based on fabricated PA-CCRs for on-off keying passive transmission links. The results demonstrated data transmission at a rate up to 5 kb/s.