Automation of radiation dosimetry using PTW dosemeter and LabVIEW™

Automation of UNIDOS “Dosemeter” using personal computer (PC) is discussed in this paper.In order to save time and eliminate human operation errors during the radiation dosimetry, suitable software, using LabVIEW™ graphical programming language, was written to automate and facilitate the processes of measurements, analysis and data storage.The software calculates the calibration factor of the ionization chamber in terms of air kerma or absorbed dose to water according to IAEA dosimetry protocols. It also has the ability to print a calibration certificate.The obtained results using this software are found to be more reliable and flexible than those obtained by manual methods previously employed.Using LabVIEW™ as a development tool is extremely convenient to make things easier when software modifications and improvements are needed.     

A case of plasma component exchange using membrane plasma separator EVACURE™

Purpose:  Performed free coagulant hemodialysis to patients having hemorrhage with the hope to avoid aggravation of bleeding caused by anticoagulant agent from dialysis. Method:  Examined 19 cases of patients with bleeding tendency, whether it is possible to perform free coagulant hemodialysis by using PAES membrane, EVAL membrane, PS membrane, Cellulose triacetate membrane and Vitamin‐E modified‐dialysis membrane. Result:  With PAES membrane, the result showed a non‐ blockade rate of 91% after four hours and 100% after two hours. Therefore, blockade was prevented with a fairly high rate. In cases of blockade, most of them were possibly avoidable with a little contrivance as the reason were lack of establish blood flow rate, faulty position of a needle, etc. Conclusions:  By using PAES membrane, it was possible to perform free coagulant hemodialysis. In order to completely have no blockade of blood lines in the future, we must strive further on.     

3-D ultrasound guidance of surgical robotics using catheter transducers: feasibility study

The goal of this study was to test the feasibility of using a real-time 3-D (RT3D) ultrasound scanner with matrix array catheter probes to guide a surgical robot. We tested the accuracy of using 3-D catheter transducers with the 3-D measurement software of the scanner to direct automatically a robot arm that touched two needle tips together within a water tank and inside a vascular graft. RMS measurement error ranged from 2.4 to 3.4 mm for two catheter designs.     

Quantitative hydrogen analysis of zircaloy-4 using low-pressure laser plasma technique

It is found in this work that variation of laser power density in low-pressure plasma spectrochemical analysis of hydrogen affects sensitively the hydrogen emission intensity from the unwanted and yet ubiquitous presence of ambient water. A special experimental setup has been devised to allow the simple condition of focusing/defocusing the laser beam on the sample surface. When applied to zircaloy-4 samples prepared with various hydrogen impurity concentrations using low-pressure helium surrounding gas, good-quality hydrogen emission lines of very high signal to background ratios were obtained with high reproducibility under weakly focused or largely defocused laser irradiation. These measurements resulted in a linear calibration line with nonzero intercept representing the residual contribution from the recalcitrant water molecules. It was further shown that this can be evaluated and taken into account by means of the measured intensity ratio between the oxygen and zirconium emission lines. We have demonstrated the applicability of this experimental approach for quantitative determination of hydrogen impurity concentrations in the samples considered.     

Quantitative analysis of deuterium using laser-induced plasma at low pressure of helium

It was proved that the analysis of deuterium can be conducted using laser-induced plasma spectroscopy. By selecting the appropriate surrounding gas, its pressure, and gating time of the detection system, it was shown that the emission lines of both hydrogen (H(alpha)) and deuterium (D(alpha)), separated by only 0.179 nm, can be fully resolved. A linear calibration curve was also obtained, indicating that this technique has the potential for quantitative analysis of deuterium. The minimum detection limit achieved in this stage of research was estimated to be 50 ppm. We have also shown that this technique can be used as a simple and rapid method for D and H analysis in solid samples.     

Automation of data collection for matrix-assisted laser desorption/ionization mass spectrometry using a correlative analysis algorithm

Automation of data collection in matrix-assisted laser desorption/ionization (MALDI) mass spectrometry using a correlative analysis algorithm is demonstrated. This algorithm was employed to compensate for mass spectral jittering in MALDI data collection (e.g., peak shifts along the m/z axis, signal intensity deviations, etc.). Several important parameters for performing correlative analysis, such as the minimum correlation coefficient to be used and number of mass spectra to acquire prior to correlation, have been investigated and optimized. In addition, the correlation algorithm improved mass resolution of low- and high-molecular-weight compounds by as much as a factor of 4. Signal reproducibility in MALDI quantitative analysis also is improved when correlation is employed for data collection. This data collection algorithm can be used in conjunction with other instrumental optimization programs to allow for fully automated MALDI analysis, which is required for the routine applications carried out in many analytical laboratories.     

Quantitative analysis of lycopene isomers in human plasma using high-performance liquid chromatography-tandem mass spectrometry

An analytical method for the determination of the concentrations of total lycopene and its cis and all-trans isomers in human plasma has been developed using high-performance liquid chromatography-tandem mass spectrometry (LC-MS-MS). This method was based on the observation that, during negative ion atmospheric pressure chemical ionization with collision-induced dissociation, a unique fragment of m/z 467 was formed from the molecular ion of m/z 536 by elimination of a terminal isoprene group. The use of multiple reaction monitoring facilitated the selective detection of lycopene isomers and an internal standard without interference from the isobaric carotenoids a-carotene and beta-carotene, which are also abundant in human plasma. Measurement of total lycopene was carried out using a C18 high-performance liquid chromatography (HPLC) column and an isocratic mobile phase consisting of acetonitrile/methyl tert-butyl ether (95:5) so that all lycopene isomers eluted as a single chromatographic peak. all-trans-Lycopene was separated from its various cis isomers by using a C30 carotenoid column and a gradient solvent system from methanol to methyl tert-butyl ether. The effects of sample preparation and handling parameters on the stability of lycopene were evaluated such as the stability of lycopene in the HPLC autosampler and the effect of saponification upon lycopene isomerization. For example, the half-life of all-trans-lycopene in the HPLC mobile phase in the autosampler at 4 degrees C was determined to be approximately 16 h. Also, saponification of plasma samples was determined to cause lycopene degradation and isomerization so that lycopene recovery was reduced. The accuracy and interassay precision of this LC-MS-MS assay for lycopene showed a standard deviation of less than 10% over the range of 5-500 pmol injected on-column. The limit of detection was 11.2 fmol injected on-column, and the limit of quantitation was 22.8 fmol.     

Studies of chemical interferences in an inductively coupled plasma using moment analysis of space-resolved emission profiles

Interelement effects induced by sodium, aluminum, and phosphate ion on calcium and magnesium emission were studied with a two-channel spectrometer that could record spatially resolved emission profiles of an atom line and an ion line simultaneously. The statistical moments of the digitized emission profiles were calculated and were employed for rate-constant estimation using our previously established theory. Interelement effects are results of interferences in the analyte atomization, ionization, and/or recombination steps. Characteristic changes will be induced in the emission profiles by each of these interferences. These changes can be characterized by the statistical moments of the corresponding profiles. Therefore, by investigating variations in the rate constants caused by the specific concomitant, one may better understand the analyte atomization-excitation mechanisms. Sodium enhances the atomic emission of both calcium and magnesium but has little effect on their ionic emission. Based on the trends of variation in the rate constants, the atomic signal enhancement seems to be attributed more to the facilitation of analyte atomization rather than to the shift of ionization equilibrium. Aluminum and phosphate ion appear not to induce significant interferences on either elements.     

International mobility of researchers in robotics,computer vision and electron devices: A quantitative and comparative analysis

We investigated author information in scientific articles by approximately 7,000 researchers for a quantitative analysis of researchers’ international mobility. From top journals, we traced the movements of more than 2,200 researchers in the research domains of robotics, computer vision and electron devices. We categorized countries’ characteristics for the balance between the inflow and the outflow of researchers moving internationally. Flow patterns of international mobility confirm that the United States, China and India exhibit the greatest global flows of researchers, with Singapore and Hong Kong attracting remarkable numbers of researchers from other countries. International mobility focusing on institutions reveals that universities in Singapore receive as many foreign researchers as do research universities in the United States. Furthermore, firms and international collaborative research institutes act as alternative receivers to the universities in the electron devices research domain.     

Automation of solid-phase microextraction in high-throughput format and applications to drug analysis

The automation of solid-phase microextraction (SPME) coupled to liquid chromatography-tandem mass spectrometry (LC-MS/MS) was accomplished using a 96 multiwell plate format, a SPME multifiber device, two orbital shakers, and a three-arm robotic system. Extensive optimization of the proposed setup was performed including coating selection, optimization of the fiber coating procedure, confirmation of uniform agitation in all wells, and the selection of the optimal calibration method. The system allows the use of pre-equilibrium extraction times with no deterioration in method precision due to reproducible timing of extraction and desorption steps and reproducible positioning of all fibers within the wells. The applicability of the system for the extraction of several common drugs is demonstrated. The optimized multifiber SPME-LC-MS/MS was subsequently fully validated for the high-throughput analysis of diazepam, lorazepam, nordiazepam, and oxazepam in human whole blood. The proposed method allowed the automated sample preparation of 96 samples in 100 min, which represents the highest throughput of any SPME technique to date, while achieving excellent accuracy (87-113%), precision (相似文献   

R.F. plasma deposition of silicon nitride layers

A versatile r.f. plasma deposition system used to deposit high quality Si₃N₄ films at low temperature (200–350°C) is described. By introducing the reactant gases separately and reactively reducing the oxygen content of the system, films which exhibited very little oxygen contamination could be deposited. Rutherford backscaterring studies were used to evaluate the atomic composition of the films. The composition was related to other parameters such as the index of refraction, the etch rate and the deposition rate. The nitride layers described here were used successfully to anneal ion-implanted GaAs with negligible surface degradation.     

Carbon analysis for inspecting carbonation of concrete using a TEA CO2 laser-induced plasma

It has been demonstrated that a spectrochemical analysis of carbon using the laser plasma method can be successfully applied to inspect the carbonation of concrete by detecting carbon produced in aged concrete by a chemical reaction of Ca(OH)2 with CO2 gas in environmental air, turning into CaCO3, which induces degradation of the quality of building concrete. A comparative study has been made using a TEA CO2 laser (500-1000 mJ) and a Q-switched Nd-YAG laser (50-200 mJ) to search for the optimum conditions for carbon analysis, proving the advantage of the TEA CO2 laser for this purpose. Also, it was clarified that laser irradiation with suitable defocusing conditions is a crucial point for obtaining high sensitivity in the detection of carbon. Practical experiments on the inspection of carbonation were carried out using both a concrete sample that had been intentionally carbonated by exposure to high concentrations of CO2 gas and a naturally carbonated concrete sample. As a result, good coincidence was observed between the laser method and the ordinary method, which uses the chemical indicator phenolphthalein, implying that this laser technique is applicable as an in situ quantitative method of inspection for carbonation of concrete.     

Effect of fractionation on the forensic elemental analysis of glass using laser ablation inductively coupled plasma mass spectrometry

Laser ablation (LA) is a powerful analytical technique for solid microsampling. Its coupling with ICPMS has been shown to offer good precision and accuracy for the elemental analysis of glass fragments. Fractionation in LA poses one of the major challenges to using this technique for in situ trace elemental profiling of glass evidence. The aim of this work was to study the effect of elemental fractionation on the forensic application of elemental analysis of glass samples by LA-ICPMS. Two different approaches were used to evaluate the fractionation: fractionation index and U/Th ratios. The resulting fractionation index values indicate low fractionation for the majority of elements evaluated, ranging between 0.8 and 1.2. The U/Th ratio suggests a higher fractionation at the beginning of the ablation process. To evaluate whether fractionation affects the quantification of glass samples by LA-ICPMS, a comparison of LA results with solution ICPMS analysis was conducted. The distribution of particle sizes during the ablation under different conditions and laser systems was also measured to evaluate the fractionation. The standard reference materials NIST 612, 610, and 1831 were analyzed in triplicate by both methods (n = 55) along with a set of 10 casework samples originating from different automobiles.