Evaluation of risk factors for uric acid elevation in COVID-19 patients treated with favipiravir.

The objective of this retrospective study was to identify the clinical risk factor associated with uric acid elevation in coronavirus disease (COVID-19) patients treated with favipiravir. Uric acid elevation was defined as an unexplained increase of ≥1.5 times in the patient's uric acid level from baseline. Twenty-nine COVID-19 patients were included in the study. Uric acid elevation developed during favipiravir therapy in 12 (41.4%) patients and the median onset time was 4.5 days after starting favipiravir. In multiple logistic regression analysis, the favipiravir dosage (adjusted OR = 1.69 [1.02-2.81], P = 0.044) and younger patient age (adjusted OR = 0.91 [0.83-0.99], P = 0.040) were significant clinical risk factors for uric acid elevation. No significant between-group difference was noted in the uric acid elevation and non-elevation groups in the clinical recovery after favipiravir therapy. The uric acid levels of patients administered with favipiravir should be monitored closely.

Intense water-window soft x-ray emission by spectral control using dual laser pulses.

We demonstrate intense emission in the water-window soft x-ray spectral region by controlling the spectral behavior through changing the balance between emissivity and self-absorption in an expanding plasma. The number of photons obtained from a dual laser irradiated target with a 150-ps pre-pulse was maximized at 3.8 × 1014 photons/sr in λ = 2.34 - 4.38 nm at a pulse separation time of 7 - 10 ns. Enhancement of the number of photons is attributed to efficient coupling with the main laser pulse while maintaining a tiny source size.

Emission of water-window soft x-rays under optically thin conditions using low-density foam targets.

The effect of optical thickness in a bismuth water-window soft x-ray source is considered by comparing the emission from laser-produced plasmas of a 7.5% atomic density foam target and a solid-density target. The number of photons recorded in the 4 nm region was comparable for both targets at a plasma-initiating laser pulse duration of 6 ns. From experiments at different pulse durations of 150 ps and 6 ns, self-absorption (opacity) effects were found to be relatively small for bismuth plasmas as compared to those of tin, based on the same emission mechanism and which are used in 13.5 nm sources for extreme ultraviolet lithography.

Rapid, simple, and clinically applicable high-performance liquid chromatography method for clinical determination of plasma colistin concentrations.

BACKGROUND: Since both the antibacterial effects and common adverse effects of colistin are concentration-dependent, determination of the most appropriate dosage regimen and administration method for colistin therapy is essential to ensure its efficacy and safety. We aimed to establish a rapid and simple high-performance liquid chromatography (HPLC)-based system for the clinical determination of colistin serum concentrations. METHODS: Extraction using a solid-phase C18 cartridge, derivatisation with 9-fluorenylmethyl chloroformate, and elution with a short reversed-phase Cl8 column effectively separated colistin from an internal standard. The HPLC apparatus and conditions were as follows: analytical column, Hydrosphere C18; sample injection volume, 50 µL; column temperature, 40 °C; detector, Shimadzu RF-5300 fluorescence spectrophotometer (excitation wavelength, 260 nm; emission wavelength, 315 nm); mobile phase, acetonitrile/tetrahydrofuran/distilled water (50,14,20, v/v/v); flow-rate, 1.6 mL/min. RESULTS: The calibration curves obtained for colistin were linear in the concentration range of 0.10-8.0 µg/mL. The regression equation was y = 0.6496× - 0.0141 (r2 = 0.9999). The limit of detection was ~ 0.025 µg/mL, and the assay intra- and inter-day precisions were 0.87-3.74% and 1.97-6.17%, respectively. The analytical peaks of colistin A, colistin B, and the internal standard were resolved with adequate peak symmetries, and their retention times were approximately 8.2, 6.8, and 5.4 min, respectively. Furthermore, the assay was successfully applied to quantify the plasma colistin levels of a haemodialysis patient. CONCLUSION: The assay is a simple, rapid, accurate, selective, clinically applicable HPLC-based method for the quantification of colistin in human plasma.

Note: development of a volume-limited dot target for a high brightness extreme ultraviolet microplasma source.

We report on production of volume-limited dot targets based on electron beam lithographic and sputtering technologies for use in efficient high brightness extreme ultraviolet microplasma sources. We successfully produced cylindrical tin (Sn) targets with diameters of 10, 15, and 20 µm and a height of 150 nm. The calculated spectrum around 13.5 nm was in good agreement with that obtained experimentally.

Note: Enhancement of the extreme ultraviolet emission from a potassium plasma by dual laser irradiation.

Emission spectra from multiply charged potassium ions ranging from K(3+) to K(5+) have been obtained in the extreme ultraviolet (EUV) spectral region. A strong emission feature peaking around 38 nm, corresponding to a photon energy of 32.6 eV, is the dominant spectral feature at time-averaged electron temperatures in the range of 8-12 eV. The variation of this emission with laser intensity and the effects of pre-pulses on the relative conversion efficiency (CE) have been explored experimentally and indicate that an enhancement of about 30% in EUV CE is readily attainable.

Determination of l-tryptophan and l-kynurenine in Human Serum by using LC-MS after Derivatization with (R)-DBD-PyNCS.

Concentrations of l-tryptophan (l-Trp) and its metabolite, l-kynurenine (l-KYN), in sera of 19 normal subjects (age: 23.6 ± 3.5 y, male: 8, female: 11) were determined by high-performance liquid chromatography with mass-spectrometric detection, following their derivatization with (R)-(-)-4-(N, N-dimethylaminosulfonyl)-7-(3-isothiocyanatopyrrolidin-1-yl)-2,1,3-benzoxadiazole (DBD-PyNCS). A significant positive correlation between l-Trp and l-KYN concentrations was observed (r = 0.532, P < 0.05). Serum l-Trp concentration in male subjects (95.65 ± 4.27 µM) was significantly higher than that in female subjects (79.20 ± 3.34 µM; P < 0.05), while no significant differences in l-KYN concentration or the l-KYN:l-Trp ratio were observed between male and female subjects.

Characteristics of extreme ultraviolet emission from mid-infrared laser-produced rare-earth Gd plasmas.

We characterize extreme ultraviolet (EUV) emission from mid-infrared (mid-IR) laser-produced plasmas (LPPs) of the rare-earth element Gd. The energy conversion efficiency (CE) and the spectral purity in the mid-IR LPPs at λL = 10.6 µm were higher than for solid-state LPPs at λL = 1.06 µm, because the plasma produced is optically thin due to the lower critical density, resulting in a CE of 0.7%. The peak wavelength remained fixed at 6.76 nm for all laser intensities studied. Plasma parameters at a mid-IR laser intensity of 1.3×10(11) W/cm(2) was also evaluated by use of the hydrodynamic simulation code to produce the EUV emission at 6.76 nm.

High resolution extreme ultraviolet spectrometer for an electron beam ion trap.

An extreme ultraviolet spectrometer has been developed for spectroscopic studies of highly charged ions with an electron beam ion trap. It has a slit-less configuration with a spherical varied-line-spacing grating that provides a flat focal plane for grazing incidence light. Alternative use of two different gratings enables us to cover the wavelength range 1-25 nm. Test observations with the Tokyo electron beam ion trap demonstrate the high performance of the present spectrometer such as a resolving power of above 1000.

Optimum arousal level preservation system using biosignals.

The purpose of this study is to develop a driver's optimum arousal level preservation system while driving. The important point of developing this system is how we keep a driver's adequate conditions on driving. Most of the systems, which have been already put to practical use, are using audible sound or warning messages on a display to urge driver to take a rest. However, arousal levels are strongly related to the balance of autonomic modulations; therefore we need the stimulation that preserves a driver's adequate condition physiologically. Some preceding studies reported that the stimulation using the biological rhythms especially heart beating rhythms are influential to human body. We gave a consideration to this fact and made a course of using driver's heartbeat rhythm for the feedback stimulation to realize the demand. In this paper, we examined the stimulation from two points of views. The one is to investigate the possibilities of controlling a driver's heartbeat rhythms by making synchronization between the driver's heartbeat and a vibratory stimulation. The other one is to find out the stimulation that induces RSA (Respiratory Sinus Arrhythmia) in order to adjust the parasympathetic modulations. The result of the experiment indicated that the 1 [s] constant beat stimulation has an effect of inducing RSA, and the stimulation using a rhythm of heartbeat has a possibility of controlling driver's heart rate variability, and its' efficiency might be possible to be improved by adjusting the rhythm of the stimulation to the driver's heartbeat rhythms.