Ultrashort pulse generation in modeless laser cavity

We demonstrate experimentally that random phase modulation of an erbium-doped fiber ring-laser by an intra-cavity electro-optic phase modulator did not inhibit ultra-short pulse operation (so-called mode-locking). Stable and self-starting operation was achieved even when the phase modulator was driven with random sequences sufficiently fast and strong to render the laser cavity modeless, as determined by heterodyne measurements. No significant change in the pulse characteristics was observed. The insensitivity to the random phase modulation is expected, given the lack of phase-sensitive elements in the cavity.Comment: Manuscript submitted to Optics Express. Final Manuscript Decisio

A CD300c-Fc Fusion Protein Inhibits T Cell Immunity

T cell responses are fine-tuned by co-stimulatory and co-inhibitory molecules. Among the T cell regulators, the B7 family members are of central importance. The recent success in targeting the B7 family molecules for the treatment of immune-related diseases has attracted intense interest in identifying additional B7-related molecules. In this study, we describe CD300c as a novel T cell co-inhibitory molecule that shares significant sequence homology with existing B7 family members. CD300c protein is expressed on professional antigen-presenting cells (APC), including B cells, monocytes, macrophages, and dendritic cells (DCs). The putative CD300c counter-receptor is expressed on CD4 and CD8 T cells, and the expression levels are upregulated upon activation. Soluble human and mouse CD300c-Fc fusion proteins significantly inhibit the proliferation, activation, and cytokine production by CD4 and CD8 T cells in vitro. Administration of CD300c-Fc protein attenuates graft-vs.-host disease (GVHD) in mice. Our results suggest that therapeutic interaction with the CD300c inhibitory pathway may represent a new strategy to modulate T cell-mediated immunity for the treatment of GVHD and autoimmune disease

A One-Dimensional Hydrodynamic and Water Quality Model for a Water Transfer Project with Multihydraulic Structures

The long Middle Route of the South to North Water Transfer Project is composed of complex hydraulic structures (aqueduct, tunnel, control gate, diversion, culvert, and diverted siphon), which generate complex flow patterns. It is vital to simulate the flow patterns through hydraulic structures, but it is a challenging work to protect water quality and maintain continuous water transfer. A one-dimensional hydrodynamic and water quality model was built to understand the flow and pollutant movement in this project. Preissmann four-point partial-node implicit scheme was used to solve the governing equations in this study. Water flow and pollutant movement were appropriately simulated and the results indicated that this water quality model was comparable to MIKE 11 and had a good performance and accuracy. Simulation accuracy and model uncertainty were analyzed. Based on the validated water quality model, six pollution scenarios (Q1 = 10 m3/s, Q2 = 30 m3/s, and Q3 = 60 m3/s for volatile phenol (VOP) and contaminant mercury (Hg)) were simulated for the MRP. Emergent pollution accidents were forecasted and changes of water quality were analyzed according to the simulations results, which helped to guarantee continuously transferring water for a large water transfer project

A permutation-combination heuristics for crane-based automated storage and retrieval systems considering order fulfillment time and energy consumption

An automated storage and retrieval system (AS/RS) is a key component of enterprise logistics. Its performance metrics include, e.g., order fulfillment time and energy consumption. A crane-based automated storage and retrieval system (CB-AS/RS) is used as the study subject in this paper to build a location allocation model with the goal of minimizing order fulfillment time and minimizing energy consumption. The two-objective problem is transformed into a single-objective problem by the weight method. A genetic algorithm (GA) is used to optimize and simulate the model using spatial mapping coding. A permutation-combination heuristics (PCH) is proposed that follows the coding method and cross-operation of the GA and conducts both arrange-operation and change-operation. During the simulation, the influence of different storage utilization rates and different output and input instruction quantities in a batch of orders on the results is considered. Experimental results show that the results of the PCH algorithm are better than the GA and the optimization results are more stable. In this paper, we provide an optimization idea for the CB-AS/RS researchers and managers

Mid-infrared Spectral Compression of Soliton Pulse in an Adiabatically Suspended Silicon Waveguide Taper

Spectral compression (SPC) can be used for generating narrow bandwidth and wavelength-tunable light sources, which have important applications in optical communication system, spectroscopy, and nonlinear microscopy. In this paper, we numerically demonstrate the high-degree SPC of the chirp-free femtosecond pulse at wavelength 2.4 μm in a 6-cm long adiabatically suspended silicon waveguide taper. The silicon waveguide taper is designed with a dispersion-increasing profile along the propagation distance z. Simulation results show that the SPC factor can be up to 10.9, along with the brightness-enhanced factor of 8.0 and negligible sidelobe. The impacts of the higher-order dispersion, higher-order nonlinearity, losses (including linear and nonlinear loss), and variation of Kerr nonlinear coefficient along z on the SPC are also investigated. It is found that variation of Kerr nonlinear coefficient γ(z) and linear loss are the dominant perturbation to the degradation of the SPC performance