[en] Laser-induced breakdown spectroscopy (LIBS) offers rapid, localized chemical analysis of solid or liquid materials with high spatial resolution in lateral and depth profiling, without the need for sample preparation. Principal component analysis and partial least squares algorithms were applied to identify a variety of complex organic and inorganic samples. This work illustrates how LIBS analyzers can answer a multitude of real-world needs for rapid analysis, such as determination of lead in paint and children's toys, analysis of electronic and solder materials, quality control of fiberglass panels, discrimination of coffee beans from different vendors, and identification of generic versus brand-name drugs. Lateral and depth profiling was performed on children's toys and paint layers. Traditional one-element calibration or multivariate chemometric procedures were applied for elemental quantification, from single laser shot determination of metal traces at ∼10 μg/g to determination of halogens at 90 μg/g using 50-shot spectral accumulation. The effectiveness of LIBS for security applications was demonstrated in the field by testing the 50-m standoff LIBS rasterizing detector.

[en] The formation of a laser-induced plasma in a cavity and the effects of a cavity on the ablation process were investigated. Cavities were fabricated in fused silica with equal depths and variable diameters to provide aspect ratios (depth/diameter) of 1, 3 and 6. The temperature and electron number density of the pulsed laser-induced plasma in the cavities were determined from spectroscopic measurements. Reflection and confinement effects by the cavity walls and plasma shielding were discussed to explain increased temperature and electron number density with increasing cavity aspect ratio. The temporal variations of the plasma temperature and electron number density sharply decreased inside the cavity. An adiabatic expansion model was not suitable for the laser-induced plasma in the cavity because plasma wall interactions were not included. Properties of laser-induced plasmas in the cavities and on a flat surface were compared

[en] Objectives: The in vivo binding analysis of vesicular monoamine transporter type 2 (VMAT2) to radioligand has provided a means of investigating related disorders. Anesthesia is often inevitable when the investigations are performed in animals. In the present study, we tested effects of four commonly-used anesthetics: isoflurane, pentobarbital, chloral hydrate and ketamine, on in vivo VMAT2 binding to "1"8F-FP-(+)-DTBZ, a specific VMAT2 radioligand, in rat brain. Methods: The transient equilibrium time window for in vivo binding of "1"8F-FP-(+)-DTBZ after a bolus injection was firstly determined. The brain biodistribution studies under anesthetized and awake rats were then performed at the equilibrium time. Standard uptake values (SUVs) of the interest brain regions: the striatum (ST), hippocampus (HP), cortex (CX) and cerebellum (CB) were obtained; and ratios of tissue to cerebellum were calculated. Results: Isoflurane and pentobarbital did not alter distribution of "1"8F-FP-(+)-DTBZ in the brain relative to the awake group; neither SUVs nor ratios of ST/CB and HP/CB were altered significantly. Chloral hydrate significantly increased SUVs of all the brain regions, but did not significantly alter ratios of ST/CB and HP/CB. Ketamine significantly increased SUVs of the striatum, hippocampus and cortex, and insignificantly increased the SUV of the cerebellum; consequently, ketamine significantly increased ratios of ST/CB and HP/CB. Conclusions: It is concluded that in vivo VMAT2 binding to "1"8F-FP-(+)-DTBZ are not altered by isoflurane and pentobarbital, but altered by chloral hydrate and ketamine. Isoflurane and pentobarbital may be promising anesthetic compounds for investigating in vivo VMAT2 binding. Further studies are warranted to investigate the interactions of anesthetics with VMAT2 binding potential with in vivo PET studies.

[en] In order to meet fast development of nuclear power, China should establish its own nuclear power standards system. This paper gives some opinions on establishment of Chinese nuclear island systems and components design and construction standards. It is suggested to draft 'Chinese Nuclear Power Utility Requirements Document'. (author)

[en] To study the expansion and cooling process of the laser induced plasma generated by nanosecond pulsed laser ablation, experiments have been conducted which measure the position of the external shockwaves and the temperature of the vapor plumes. The positions of external shockwaves were determined by a femtosecond laser time-resolved imaging system. Vapor plume temperature was determined from spectroscopic measurements of the plasma emission lines. A model which considers the mass, momentum, and energy conservation of the region affected by the laser energy was developed. It shows good agreement to the experimental data

[en] In order to meet fast development of nuclear power, China should establish its own nuclear power standards system. This paper gives some opinions on establishment of Chinese nuclear island systems and components design and construction standards. It is suggested to draft 'Chinese Nuclear Power Utility Requirements Document'. (author)

[en] Cavity formation is a frequent result in many laser ablation applications. Although most theoretical investigations have been devoted to laser ablation on a flat surface, the development of a laser plasma inside a cavity is of both fundamental as well as practical significance. In this study, the temperature and electron number density of laser-induced plasmas in fused silica cavities were determined using spectroscopic methods. The effects of cavity aspect ratio on plasma properties were investigated. The temperature and electron number density of laser-induced plasma were measured to be much higher and to decrease faster for a plasma inside a cavity than on the flat surface. Cavity wall influences on the plasma expansion are discussed

[en] In this paper, we report preparation and biodistribution in mice of ¹⁸F-Fallypride, a dopamine D2 receptor PET imaging agent. ¹⁸F-Fallypride was prepared by nucleophilic fluorination of (s)-N-[(1-allyl-2-pyrrolidinyl)methyl] -5-(3-tolunesulfonyloxypropyl)-2,3-dimethoxybenzamide with K¹⁸F/K₂₂₂(Kryptofix) in a chemical process control unit. Purity and stability of the ¹⁸F-Fallypride were checked by HPLC and TLC, the dynamic distribution in brain and critical organs of ICR mice were studied. The radiolabelling yield of ¹⁸F-Fallypride was 40.75% and the radiochemistry purity was over 97%. The whole process (including synthesis, purification and analysis) took only 40 minutes. After 4 hours in room temperature, the radiochemical purity of ¹⁸F-Fallypride was still over 95%. The striatum uptake was good, the striatum/cerebellum ratio reached 14.27 at 120 min. Among the critical organs, kidney had the first and the highest uptake (9.91±1.24 %ID·g^-1). All organs had quick clearance (T_1/2<1 h). The radioactivity in bone increased with time. The results show that ¹⁸F-Fallypride has a high striatum uptake and a high striatum/ cerebellum ratio. ¹⁸F-Fallypride is a good dopamine D2 receptor agent. The autosynthesis method of ¹⁸F-Fallypride is simple and fast with high labeling yield and high radiochemical purity. This method is fit for clinic use. (authors)

[en] Objective: To study the quality control methods for ⁹⁹Tc^m-TRODAT-1 kit and injection. Methods: The appearance, pH, contents of the bases, the labeling yield, asepsis and bacterial endotoxins of ⁹⁹Tc^m-TRODAT-1 kits from three different batches were examined. The kit stability was estimated under different conditions. The transparence, pH, radiochemical purity, half-life, asepsis and bacterial endotoxins of ⁹⁹Tc^m-TRODAT-1 injection were tested. Results: The ⁹⁹Tc^m-TRODAT-1 kit and injection were both achromous and transparent, with pH values being 5.9 ± 0.1 and 5.5-7.0 respectively. The contents of stannous chloride and TRODAT-1 were stable. The labeling yield of the kit and the radiochemical purity of the injection were both ≥95%.The asepsis test demonstrated that the characters of ⁹⁹Tc^m-TRODAT-1 kit and injection were qualified. TRODAT-1 kit was stable at 0-4 ℃ for 6 months or at room temperature (20-25 ℃ )for 10 days, and the radiochemical purity of the injection was still >90% at room temperature for 8 hours. Conclusions: The quality control methods for ⁹⁹Tc^m-TRODAT-1 kit are simple and practical. The kit and injection are qualified and can be used for clinical application. (authors)

[en] Highlights: • Configuration, parameters, performance of the direct LIBS analyzer of liquid samples. • LOD in oil and solvent (proxy to kerosene) as low as 0.01–0.04 ppm for Li, Mg, Cu. • RSD of measurements of 100 ppm vanadium in oil and solvent was less than 1.5%. • LOD, repeatability better than required for oil analysis in ICP-OES by ASTM D5185. • LIBS displayed ability to measure the hydrogen-to-carbon ratio in liquid samples. A prototype analyzer for the direct LIBS analysis of nebulized liquid samples was developed and tested, particularly for the analysis of petroleum, organic solvents and aqueous solutions. The LIBS analyzer requires about 750 μl of liquid sample, 1 l of N₂ gas, and 10 s of the analysis time to record 100 spectra. The limits of detection in oil and solvent are as low as 0.01–0.04 ppm for Li, Mg, and Cu. They increase for the difficult elements, such as Pb and Hg (7–10 ppm), Cl (250 ppm), and S (~0.7%). The relative standard deviation of measuring 100 ppm vanadium in oil and solvent was 1.5%. The LIBS detection limits and repeatability are better than required by the standard method ASTM D5185 for the analysis of lubricating oils in ICP-OES. Several petroleum samples were analyzed by LIBS and the quantitative results for V, Ni, and Fe compared to the ICP-OES data. Light crude oils can be nebulized and analyzed directly. Medium crude oils may require minimal dilution at least 1:1, otherwise errors of determination may become large. Presumably, utilization of the internal standard and chemometrics can be useful to correct for the matrix effects. In addition to the trace element analysis, the LIBS prototype demonstrated ability to measure the hydrogen-to‑carbon ratio in organic liquid samples. Several unidentified features were observed in the carbon spectrum. Their possible origin is discussed.