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A Nulsen

Publications and source records attributed to A Nulsen.

3 recordsLinked to original sources
PubMed2005

Nonlinear propagation effects in antiresonant high-index inclusion photonic crystal fibers.

We experimentally and numerically investigate femtosecond-pulse propagation in a microstructured optical fiber consisting of a silica core surrounded by airholes that are filled with a high-index fluid. This fiber combines the resonant properties of hollow-core bandgap fibers and the high nonlinearity of index-guiding waveguides. A range of nonlinear optical effects can be observed, including soliton propagation, dispersive wave generation, and a Raman self-frequency shift. Tuning the center wavelength of the laser and varying the refractive index of the fluid lead to different propagation effects, mediated by the strongly wavelength-dependent group-velocity dispersion in these photonic bandgap confining structures.

Journal Article↗
PubMed1974

Cigarette smoking, air pollution, and immunity: a model system.

BALB/c mice were exposed to fresh cigarette smoke, a mixture of SO(2) (5 ppm) and CO (50 ppm), or both for periods up to 18 weeks. After varying exposure times, animals were intratracheally inoculated with 10(8) sheep erythrocytes and sacrificed 7 days later, during which time the various exposure regimes were continued. Plaque-forming-cell responses were measured in spleens and a pool of the cervical and mediastinal lymph nodes, together with serum hemagglutinating and hemolytic responses, and compared with those of age-matched control animals. Both the organ and serum responses exhibited stimulation in the early phase of exposure, before a depression with prolonged exposure. The greatest depression was seen in animals that had been chronically exposed to both fresh cigarette smoke and the gas mixture.

Air Pollution↗