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. He1+ ions with 54.42-eV ionization potential extend the harmonic cutoff energy to 1 keV. The transverse selective-zoning method of quasi-phase-matching is utilized to overcome the severe plasma dispersion in a highly ionized medium. The calculated conversion efficiency reaches about 15% of the perfect phase-matching condition. Wavelength tunability is achieved by incorporating a programmable spatial-light modulator to control the quasi-phase-matching pattern.

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. The anterior-posterior (AP) diameters and AP/transverse (T) diameter ratios were greater at the end of deep inspiration than that at the end of deep expiration for each sex (p < 0.01). The anterior-posterior dimensional changes were greater than lateral airway dimensional changes each sex (p < 0.05). Ultrasonography could provide realistic impression of the process on the oropharynx movement during deep breathing and perform the quantitative analysis of the oropharynx airway lumen changes during deep breathing. The results were encouraging and supported the utility of ultrasonography in future studies.

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. The reliability and reproducibility studies were conducted in 40 healthy volunteers. RESULT: The air-filled upper airway appeared as a bright heterogeneous hyperechoic line. During deep inspiration, the upper airway lumen expanded to the highest anterior-posterior dimension, whereas during deep expiration, the lateral dimension tended to increase. The sonographic measurements had good reproducibility, with intraclass correlation coefficient ranging from 0.722 to 0.887 and 0.727 to 0.882 for interobserver and intraobserver reliability, respectively. CONCLUSIONS: Ultrasonography can determine the anatomy of the upper airway and perform the quantitative analysis of the upper airway lumen during respiration. The results were encouraging and support the utility of ultrasonography in future airway disorder studies.