Standard gases are used for quality control and quality assurance, development of analysis methods and novel air sampling devices. The use of solid-phase microextraction (SPME) and other novel technologies for research in the area of air sampling and analysis requires systems/devices for reliable standard gas generation and sampling. In this paper we describe a new gas standard generating system for volatile organic compounds (VOCs) and semi-VOCs that was designed, built, and tested to facilitate fundamental and applications research with SPME. The system provided for the generation of a wide range of VOC/semi-VOC concentrations and mixing various standard gases, estimation of detection limits, testing the effects of sampling time, air temperature and relative humidity, testing the effects of air velocity and ozone on sampling/extractions. The system can be also used for calibrations of analytical instrumentation, quality control and quality assurance checks, and cross-validations of SPME with/and other sampling techniques.
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http://dx.doi.org/10.1016/j.chroma.2003.10.079 | DOI Listing |
Indian J Nucl Med
November 2024
Center for Research and Production of Radioisotopes, Dalat Nuclear Research Institute, Vietnam Atomic Energy Institute (VINATOM), Da Lat City, Lam Dong Province, Vietnam.
Aims: This study aimed to evaluate the principal technical characteristics of a well-type gas-filled ionization chamber dose calibrator used in measuring radiopharmaceutical activity, namely accuracy, repeatability, and linearity. Furthermore, this work also explored the correlation between the device's response and the position and volume of the radiopharmaceutical I-131.
Materials And Methods: Experimental measurements were conducted on the ATOMLAB 500 dose calibrator using NIST traceable Cs-137 source to determine the accuracy and repeatability.
Indian J Nucl Med
November 2024
Department of Nuclear Medicine and Molecular Imaging, Homi Bhabha Cancer Hospital and Mahamana Pandit Madan Mohan Malaviya Cancer Centre, Tata Memorial Centre, Homi Bhabha National Institute, Varanasi, Uttar Pradesh, India.
Background: Prostate-specific membrane antigen (PSMA) has shown to be a promising agent for prostate cancer imaging under PET-CT. With the automation in radiolabeling with 68Ga, using iTG 68Ge/68Ga generator, it has helped introduce various new diagnostic agents and achieve good manufacturing practices (GMP) simultaneously. However, before any radiopharmaceutical is put into clinical usage, it should always be checked for its radiochemical purity and other quality parameters before injecting in the patient.
View Article and Find Full Text PDFAm J Clin Nutr
January 2025
Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada. Electronic address:
Background: Omega-3 long chain polyunsaturated fatty acids (LCPUFAs) are important dietary components for maternal and infant health during pregnancy and lactation.
Objective: This study investigated determinants of maternal and infant LCPUFAs status at three months postpartum and the relationship between maternal serum, mother's milk, and infant LCPUFAs.
Methods: This cross-sectional study included mothers (n=1481) and their offspring (n=526) at three months postpartum from the APrON cohort.
Talanta
January 2025
Department of Chemistry, School of Forensic Medicine, China Medical University, Shenyang, 110122, China. Electronic address:
Miniaturized optical emission spectrometric (OES) devices based on various microplasma excitation sources provide a reliable tool for in-situ elemental analysis. The key to improving analytical performance is enhancing the excitation capability of the microplasma source in these devices. Here, dielectric barrier discharge (DBD) and point discharge (PD) technologies are combined to construct an enhanced dual-stage excitation source (called DBD-PD), which improves the overall excitation efficiency and OES signal sensitivity.
View Article and Find Full Text PDFJ Chem Theory Comput
January 2025
Thermodynamics Research Center, National Institute of Standards and Technology, Boulder, Colorado 80305-3337, United States.
Our recently developed approach based on the local coupled-cluster with single, double, and perturbative triple excitation [LCCSD(T)] model gives very efficient means to compute the ideal-gas enthalpies of formation. The expanded uncertainty (95% confidence) of the method is about 3 kJ·mol for medium-sized compounds, comparable to typical experimental measurements. Larger compounds of interest often exhibit many conformations that can significantly differ in intramolecular interactions.
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