Numerical experiment of phase-matched ion-based high-order harmonic generation in the water-window x-ray spectral region via electromagnetic envelope equation.

We present a phase-matching scheme for efficient high-order harmonic generation in the water-window x-ray spectral region using a 405-nm driving pulse. A high-intensity pulse (∼10 W/cm) is used to produce He ions as the target medium, increasing the cutoff photon energy to the water-window x-ray spectral region. By adjusting the driving pulse divergence, the positive dipole phase variation balances the negative plasma dispersion and geometrical phase shift, achieving phase matching.

Ion-based high-order harmonic generation from water window to keV region with a transverse disruptive pulse for quasi-phase-matching.

A scheme for ion-based high-harmonic generation from water window to keV x-ray is investigated. He ions with 54.42-eV ionization potential extend the harmonic cutoff energy to 1 keV.

Sonographic Assessment of Oropharynx Movement During Deep Breathing.

To investigate the feasibility of ultrasonography in detecting the oropharynx movement during deep breathing and to quantitatively analyze oropharynx airway lumen changes during deep breathing. The motions of oropharynx were monitored, and sonographic measurements of airway lumen were obtained during deep breathing in 448 healthy volunteers. Adequate visualization of oropharynx movement was obtained on all healthy volunteers.

Contrast-enhanced Ultrasound in evaluating of angiogenesis and tumor staging of nasopharyngeal carcinoma in nude mice.

Objective: To explore the use of Contrast-enhanced Ultrasound (CEUS) in evaluating angiogenesis in a xenograft nasopharyngeal carcinoma (NPC) model in nude mice and the evolution of CEUS parameters according to the growth of NPC.

Methods: Nude mice were divided into three groups according to experiments conducted at various times from tumor implantation (8 mice/group; group A: 4 weeks from implantation; group B:6 weeks from implantation; group C:8 weeks from implantation). CNE-2 cells were transplanted in 24 nude mice and CEUS evaluations of the tumors were performed at 4, 6 or 8 weeks from implantation.

Investigation of the Upper Airway Anatomy With Ultrasound.

Objective: The aims of this study were to describe the relationship between the scanning planes and appearance of the upper airway on sonography and to demonstrate the reliability and reproducibility of sonographic measurements of the upper airway.

Methods: Airway sonoanatomy was recognized by comparing the airway images and the corresponding cadaver's anatomical specimens. Systemic sonographic examination of 267 healthy volunteers was conducted to obtain the sonographic measurement of airway lumen.