Quantification of aluminum in human bone with neutron activation analysis

In Vivo Neutron Activation Analysis (IVNAA) has been investigated to measure aluminum levels in bone for several years. Aluminum, being a toxic element, should be routinely monitored in both clinical and occupational environments. The non-invasisve IVNAA technique developed at the McMaster University Accelerator Lab is currently being improved for future use. New sets of hand phantoms were prepared that closely resemble spectra that were collected from the hand of healthy subject. Following the IVNAA of aluminum phantoms, the technique was applied for the first time to measure bone A1 levels in 18 healthy subjects. The mean hand bone A1 concentration was determined as 28 µg A1/g Ca. The results were achieved with a dose equivalent of 17.6 mSv. Further investigations using an enhanced detection system and applying optimazation of the irradiation protocol with radiation dose up to 50 mSv showed that minimum detectable limit was improved to 0.10 mg A1.

Quantification of aluminum in human bone with neutron activation analysis

In Vivo Neutron Activation Analysis (IVNAA) has been investigated to measure aluminum levels in bone for several years. Aluminum, being a toxic element, should be routinely monitored in both clinical and occupational environments. The non-invasisve IVNAA technique developed at the McMaster University Accelerator Lab is currently being improved for future use. New sets of hand phantoms were prepared that closely resemble spectra that were collected from the hand of healthy subject. Following the IVNAA of aluminum phantoms, the technique was applied for the first time to measure bone A1 levels in 18 healthy subjects. The mean hand bone A1 concentration was determined as 28 µg A1/g Ca. The results were achieved with a dose equivalent of 17.6 mSv. Further investigations using an enhanced detection system and applying optimazation of the irradiation protocol with radiation dose up to 50 mSv showed that minimum detectable limit was improved to 0.10 mg A1.

Levels and Distributions of 210Pb and 210Po in Selected Seafood Samples in China and Assessment of Related Dose to Population

In this study, the activity concentrations levels of 210Pb and 210Po in the edible portions of eight seafood samples collected from the Fujian coast of China were determined. The activity concentrations ranged from 0.74 ± 0.08 to 12.6 ± 1.0 Bq/kg for 210Po and from the minimum detectable limit (MDL, 0.80 Bq/kg) to 11. 7 ± 1.1 Bq/kg for 210Pb. The 210Po activity concentration in all the fish organs ranged from 0.68 to 204 Bq/kg (w.w.), and the 210Po activity was mainly concentrated in the stomach, spleen, heart, liver, gonad, and intestine samples. The 210Pb activity concentration in all the fish organs ranged from the MDL to 15.2 Bq/kg (w.w.), and the 210Pb activity was concentrated in the head, fish scale, and gill samples. The annual effective ingestion doses ranged from 82.8 to 255 μSv/a for all age groups, and the lifetime risk of cancers were estimated. Both the effective ingestion doses and cancer risk to humans were within the acceptable ranges.

Differential Expression of Host Biomarkers in Saliva and Serum Samples from Individuals with Suspected Pulmonary Tuberculosis

The diagnosis of tuberculosis remains challenging in individuals with difficulty in providing good quality sputum samples such as children. Host biosignatures of inflammatory markers may be valuable in such cases, especially if they are based on more easily obtainable samples such as saliva. To explore the potential of saliva as an alternative sample in tuberculosis diagnostic/biomarker investigations, we evaluated the levels of 33 host markers in saliva samples from individuals presenting with pulmonary tuberculosis symptoms and compared them to those obtained in serum. Of the 38 individuals included in the study, tuberculosis disease was confirmed in 11 (28.9%) by sputum culture. In both the tuberculosis cases and noncases, the levels of most markers were above the minimum detectable limit in both sample types, but there was no consistent pattern regarding the ratio of markers in serum/saliva. Fractalkine, IL-17, IL-6, IL-9, MIP-1β, CRP, VEGF, and IL-5 levels in saliva and IL-6, IL-2, SAP, and SAA levels in serum were significantly higher in tuberculosis patients (P<0.05). These preliminary data indicate that there are significant differences in the levels of host markers expressed in saliva in comparison to those expressed in serum and that inflammatory markers in both sample types are potential diagnostic candidates for tuberculosis disease.

A Novel Method to Determinate Nonylphenol Contents in Water Samples Based on Laccases Cetyltrimethyl Ammonium Bromide-Carbon Paste Electrode

The eznyme biosensor(EB) as a sort of biosensors are widely used analyse target substances from samples of medicine, environment and food processing in recent years. During the EB preparation, effective immobilization of enzyme is a key step related with the activity of enzyme and the lifetime of EB. In current research, a method to determine nonylphenol(NP) contents in the water samlples has been developed on the base of laccases cetyltrimethyl ammonium bromide -carbon paste electrode. The experimental results showed that the EB developed in this optimized conditions, its minimum detectable limit could reach 0.2µg／L, and the recovery was in the range from 91% to 109% at the concentrations form 3.0×10-4 mol.L-1 to 5.0×10-6 mol.L-1. The sensor is perfect which is convenient, effective, and cheap and really can be used practice.

Reduction of Patulin during Apple Juice Clarification

Patulin is a mycotoxin produced by a number of molds involved in fruit spoilage. This compound is carcinogenic and teratogenic. Various methods are currently used to reduce the levels of patulin in apple juice, namely, charcoal treatment, chemical preservation (sulfur dioxide), gamma irradiation, fermentation, and trimming of fungus-infected apples. Many of these processes are expensive and time-consuming. Therefore, there is a need to find a convenient and economical process to control patulin levels. This study was undertaken to evaluate the effectiveness of several clarification processes for the reduction of patulin. Clarification was carried out on a laboratory scale. Apple pulp was spiked with patulin, pressed, and clarified using four different processes, namely, fining with bentonite, enzyme (pectinase)treatment, paper filtration, and centrifugation. Patulin was recovered from the clarified juice by liquid-liquid extraction, and solid-phase chromatography was used for sample cleanup prior to analysis by high-performance liquid chromatography (HPLC). The minimum detectable limit using HPLC was 20 μg/liter. Pressing followed by centrifugation resulted in an average toxin reduction of 89%. Total toxin reduction using filtration, enzyme treatment, and fining were 70, 73, and 77%, respectively. Patulin reduction was due to the binding of the toxin to solid substrates that was verified by analyzing the clarified juice as well as the filter cake, pellet, and sediment. The combined concentrations correlated to the spiked concentration. These results reveal that clarification was successful in the reduction of patulin levels in apple juice. However, clarification resulted in high levels of patulin in the pressed pulp after filtration and centrifugation, and this could be harmful if they are used as animal feeds.

Comparison Of A Mosaic-Crystal Spectrometer To Ahigh-Performance Solid-State Detector For X-Ray Microfluorescence Analysis

ABSTRACTThe minimum-detectable-limit of a compact double-focusing graphite mosaic-crystal spectrometer is compared to the minimum-detectable-limit from a high-performance Ge solidstate detector. The solid angle and efficiency of the solid-state detector is much greater than for the crystal spectrometer. However, the better signal-to-noise of the spectrometer and its insensitivity to matrix fluorescence and scattering can give it a better minimum-detectable-limit for trace element analysis. The relative advantages of the two detectors are illustrated for some simple test samples. The performance of the crystal spectrometer compared to the solid-state detector increases as the flux in the x-ray probe increases. This makes crystal spectrometers especially interesting for use with new high intensity 3rd generation synchrotron microprobes. An estimate is made of the source and sample conditions favored for each detector.

Quantitation of the Nitrosamine 2-EthylhexyI-4-(N-Methyl-N-Nitrosoamino) Benzoate (NPABAO) in Sunscreen Products

We have devised a method to quantitate the nitrosamine, 2- ethylhexyM-(N-methyl-N-nitrosoamino) benzoate (NPABAO), In commercial products containing the sunscreen ingredient, Padimate 0. The method involves a minimum of cleanup steps to afford a nonaqueous extract from product emulsions suitable for analysis by a liquid chromatograph Interfaced to a thermal energy analyzer (LC/TEA). The method Is applicable to lotions, creams, and gels. Oils are normally soluble In the mobile phase and can be analyzed directly on the LC/TEA without additional cleanup procedures. The method has a minimum detectable limit of about 30 ppb and yields &gt; 80% recovery. It is highly reproducible and generates no NPABAO artifactually prior to quantitation on the LC/TEA Application of the method to 22 different commercial product formulas disclosed that the level of NPABAO in each of the products Is below 250 ppb, with 18 of the products containing less than 100 ppb. Of interest was the observation that musk ketone, a common fragrance constituent, produces a false-positive TEA response that can Interfere with accurate analysis of NPABAO content In typical commercial products

Diethylsilane as a Silicon Source for the Deposition of Silicon Nitride and Silicon Oxynitride Films by LPCVD

ABSTRACTA purified diethylsilane (DES), LTO-410TM, has been studied as a silicon precursor for the deposition of silicon nitride and silicon oxynitride films by LPCVD. In the temperature range from 650 to 725°C mixtures of DES and NH3 produce uniform, oxidation resistant silicon nitride layers. Auger and RBS analyses show that the carbon concentrations in the films are correlated with the DES partial pressures. The film refractive indices also correlate with the carbon levels in the films for a fixed deposition temperature. Mixtures of DES, NH3, and N2O deposit silicon oxynitride films in the temperature range from 650 to 700°C with compositions controlled by the NH3:N2O ratio for a fixed DES flow. These films have carbon levels below the minimum detectable limit of Auger and RBS analyses.

Gas-Liquid Chromatographic Determination of 3,6-Dichloropicolinic Acid in Soils

A gas-liquid chromatographic (GLC) method has been developed for the determination of the experimental herbicide 3,6-dichloropicolinic acid (Dowco 290) in soils. The method involves extraction of 1 g soil samples with 1N NaCl at approximately pH 7, methylation with diazomethane utilizing a microgenerator, and detection by electron capture GLC. Interferences are small, so that a cleanup step is not necessary even at the 6 ppb level. The procedure is rapid, requiring only 45 min/sample. Recoveries range from 84 to 94% at the 6–1000 ppb level with a minimum detectable limit of 6 ppb. Standard deviations for the percentage recovery values vary from 10.9 to 2.3 for the tested range of 6.7–670 ppb, respectively.