Quantitative gas pressure measurement by molecular spectroscopy using chip-based supercontinuum in the mid-infrared.

We demonstrate the quantitative pressure measurement of gas molecules in the mid-infrared using chip-based supercontinuum and cepstrum analysis without additional measurements for baseline normalization. A supercontinuum generated in an on-chip waveguide made of chalcogenide glass having high nonlinearity passes through CO gas and provides a transmission spectrum. The gas absorption information is deconvoluted from the original supercontinuum spectral information containing temporal fluctuation by cepstrum analysis and extracted simply by applying a bandpass filter in the temporal domain. The gas pressure estimated from the extracted absorption information is consistent with the value measured by a pressure gauge within a difference of 1.25%, despite spectral fluctuations in the supercontinuum baseline comparable to the spectral depth of the gas absorption lines.

Generation of continuous-wave single-frequency 1.5 W 378 nm radiation by frequency doubling of a Ti:sapphire laser.

We have generated continuous-wave single-frequency 1.5 W 378 nm radiation by frequency doubling a high-power Ti:sapphire laser in an external enhancement cavity. An LBO crystal that is Brewster-cut and antireflection coated on both ends is used for a long-term stable frequency doubling. By optimizing the input coupler's reflectivity, we could generate 1.5 W 378 nm radiation from a 5 W 756 nm Ti:sapphire laser. According to our knowledge, this is the highest CW frequency-doubled power of a Ti:sapphire laser.

External-cavity frequency doubling of a 5-W 756-nm injection-locked Ti:sapphire laser.

We have developed a 5-W 756-nm injection-locked Ti:sapphire laser and frequency-doubled it in an external enhancement cavity for the generation of watt-level 378-nm single-frequency radiation, which is essential for isotope-selective optical pumping of thallium atoms. With a lithium triborate (LBO) crystal in the enhancement cavity, 1.1 W at 378 nm was coupled out from the cavity. Such results are to our knowledge the highest powers of continuous-wave single-frequency radiation generated from a Ti:sapphire laser and its frequency doubling.

[Clinical characteristics of 159 cases of acute toxic hepatitis].

BACKGROUNDS/AIMS: Toxic hepatitis has recently been discovered to be a major cause of acute hepatitis. We studied the clinical features and prognosis of patients diagnosed with toxic hepatitis at a single institution. METHODS: A retrospective analysis was performed using medical records of 159 cases of toxic hepatitis that were diagnosed from March 2003 to March 2008. Patients were selected based on a RUCAM score of 4 or above. RESULTS: The incidence was higher in women (n=97) than in men (n=62). The age (mean+/-SD) of the patients was 51+/-15 years . The major causes of the disease included the use of Korean traditional therapeutic preparations (34.0%), herbal medicines (41.5%), and drugs prescribed by a physician (23.9%). At the time of admission, jaundice was the most common symptom (41.5%), and the results of a liver serum battery were as follows: aspartate aminotransferase, 729.4+/-877.0 IU/L; alanine aminotransferase, 857.1+/-683.0 IU/L; total bilirubin, 6.4+/-6.5 mg/dL; and alkaline phosphatase, 209.8+/-130.0 IU/L. The hospitalization period was 10.0+/-9.5 days, and the duration of recovery from liver injury was 31.0+/-29.5 days. The factors associated with the hospitalization period included the presence of anorexia and the serum levels of albumin and bilirubin at the time of admission (P<0.05). A high serum bilirubin level and a history of alcohol ingestion were associated with a delayed recovery (Plt;0.05). The sex, age, BMI, and duration of medication were not significantly related to the hospitalization and recovery periods. CONCLUSIONS: The main cause of acute toxic hepatitis in the current study was the use of herbal medicines. The severity of liver injury at the time of admission was a major factor significantly associated with the hospitalization and recovery periods.

Development of a 756 nm, 3 W injection-locked cw Ti:sapphire laser.

We have developed a 756 nm, 3 W single-frequency cw Ti:sapphire laser by using the technique of injection locking. A cw Ti:sapphire laser in a ring-type configuration was forced to lase unidirectionally by use of an optical diode to prevent a high-power backward laser from disturbing the injection laser. A master laser was amplified by a broad-area laser diode and coupled into a single-mode fiber to generate a 50 mW injection laser with a Gaussian beam profile, which was enough to lock the Ti:sapphire laser at full power of 3 W. Such a high-power single-frequency Ti:sapphire laser enables a watt-level blue or near-ultraviolet single-frequency laser to be generated by frequency doubling.