Portable x-ray fluorescence for the analysis of chromium in nail and nail clippings.

Assessment of chromium content in human nail or nail clippings could serve as an effective biomarker of chromium status. The feasibility of a new portable x-ray fluorescence (XRF) approach to chromium measurement was investigated through analysis of nail and nail clipping phantoms. Five measurements of 180s (real time) duration were first performed on six whole nail phantoms having chromium concentrations of 0, 2, 5, 10, 15, and 20µg/g.

Assessing arsenic and selenium in a single nail clipping using portable X-ray fluorescence.

The feasibility of measuring arsenic and selenium contents in a single nail clipping was investigated using a small-focus portable X-ray fluorescence (XRF) instrument with monochromatic excitation beams. Nail clipping phantoms supplemented with arsenic and selenium to produce materials with 0, 5, 10, 15, and 20µg/g were used for calibration purposes. In total, 10 different clippings were analyzed at two different measurement positions.

Physiologically based modeling of lead kinetics: a pilot study using data from a Canadian population.

The Canadian population is currently subject to low, chronic lead exposure and an understanding of its effects is of great significance to the population's health. Such low exposure is difficult to measure directly; approximation by physiologically based modeling may provide a preferable approach to population analysis. The O'Flaherty model of lead kinetics is based on an age-dependent approach to human growth and development and devotes special attention to bone turnover rates.

Evaluation of a novel portable x-ray fluorescence screening tool for detection of arsenic exposure.

A new portable x-ray fluorescence (XRF) screening tool was evaluated for its effectiveness in arsenic (As) quantification in human finger and toe nails ([Formula: see text]). Nail samples were measured for total As concentration by XRF and inductively coupled plasma-mass spectrometry (ICP-MS). Using concordance correlation coefficient (CCC), kappa, diagnostic sensitivity (Sn) and specificity (Sp), and linear regression analyses, the concentration of As measured by XRF was compared to ICP-MS.

Portable x-ray fluorescence for assessing trace elements in rice and rice products: Comparison with inductively coupled plasma-mass spectrometry.

Portable x-ray fluorescence (XRF) was investigated as a means of assessing trace elements in rice and rice products. Using five measurement trials of 180 s real time, portable XRF was first used to detect arsenic (As), manganese (Mn), iron (Fe), nickel (Ni), copper (Cu), and zinc (Zn) in a variety of rice samples. The same samples were then microwave-digested and used to determine elemental concentrations using inductively coupled plasma-mass spectrometry (ICP-MS).

Factors influencing uncertainties of in vivo bone lead measurement using a (109)Cd K X-ray fluorescence clover leaf geometry detector system.

A (109)Cd K X-ray fluorescence (KXRF) measurement system consisting of four detectors in clover-leaf geometry is a non-invasive, low-radiation-dose method of measuring bone lead concentration. Its high precision in estimating the bone lead content makes it a promising tool for the determination of the low levels of lead currently found in the general population. After developing the clover-leaf geometry system, the system was used for the first time in a major survey in 2008 to measure the lead levels of 497 smelter employees (an occupationally exposed group with high lead levels).

X-ray fluorescence measurements of arsenic micro-distribution in human nail clippings using synchrotron radiation.

Arsenic (As) distribution in nail clippings from three healthy human subjects was investigated using the microbeam experimental setup of the hard x-ray micro-analysis (HXMA) beamline from the Canadian Light Source (CLS) synchrotron. A pair of toenail and fingernail clippings was collected from each of three subjects (one contributed two fingernail clippings). The fingernail and toenail clippings were embedded in polyester resin and cut in cross-sectional slices with an average thickness of 270 µm.

In vivo measurement of lead in the bones of smelter workers using the four-element 'clover-leaf' geometry detector system.

A total of 497 smelter employees from New Brunswick participated in a bone lead survey conducted by McMaster University in 2008 to examine the efficiency of lead exposure control programmes and a four-element 'clover-leaf' geometry detector system. Nearly 42% of the subjects had participated in both the previous surveys performed in 1994 and 1999. After developing the clover-leaf geometry system in 2006, the reliability of the system based on examining the consistency of four detectors and improving the minimum detection limit (MDL) was tested for the first time in 2008 by measuring lead levels of a large population that was occupationally exposed to lead.

The radiation dose from a proposed measurement of arsenic and selenium in human skin.

Dose measurements following 10 min irradiations with a portable x-ray fluorescence spectrometer composed of a miniature x-ray tube and a silicon PiN diode detector were performed using thermoluminescent dosimeters consisting of LiF:Mg,Ti chips of 3 mm diameter and 0.4 mm thickness. The table-top setup of the spectrometer was used for all measurements.

Simultaneous assessment of arsenic and selenium in human nail phantoms using a portable x-ray tube and a detector.

A novel approach to the measurement of arsenic and selenium in nail phantoms is demonstrated. Two-component nail phantoms of 0.7 mm and 1.

Real-time monitoring of arsenic filtration by granular ferric hydroxide.

Contamination of drinking water by arsenic is a serious public health issue in many parts of the world. One recent approach to this problem has been to filter out arsenic by use of granular ferric hydroxide (GFH), an adsorbent developed specifically for the selective removal of arsenic from water. Previous studies have documented the efficiency and high treatment capacity of this approach.

Simultaneous detection of As and Se in polyester resin skin phantoms.

It is known that As and Se act as metabolic antagonists. Hence, an improvement in assessing As-related health risks can be achieved by simultaneous quantitative measurements of both As and Se levels in the human body. In this paper, the simultaneous detection of trace concentrations of As and Se in polyester resin skin phantoms was demonstrated.

Hospital employee job resourcefulness: an empirical study and implications for health care marketing.

In today's competitive hospital marketing environment, it is imperative that administrators ensure that their hospitals are operating as efficiently and as effectively as possible. "Doing more with less" has become a mandate for hospital administrators and employees. The current research replicates and extends previous work devoted to this topic by examining the job resourcefulness construct in a hospital setting.

K-shell X-ray fluorescence measurements of arsenic depth-dependent concentration in polyester resin discs using the fundamental parameter method.

In the realm of X-ray fluorescence (XRF) applications, inhomogeneous distribution of an element can occur as a function of depth within a sample. An example is the measurement of arsenic in skin; arsenic binds with non-uniformly distributed keratin. In this paper, an XRF signal equation based on the fundamental parameter (FP) method, which explicitly takes into account the depth dependence of the elemental concentration, was developed.

Intracrystalline urinary proteins facilitate degradation and dissolution of calcium oxalate crystals in cultured renal cells.

We have previously proposed that intracrystalline proteins would increase intracellular proteolytic disruption and dissolution of calcium oxalate (CaOx) crystals. Chauvet MC, Ryall RL. J Struct Biol 151: 12-17, 2005; Fleming DE, van Riessen A, Chauvet MC, Grover PK, Hunter B, van Bronswijk W, Ryall RL.

A rapid, high sensitivity technique for measuring arsenic in skin phantoms using a portable x-ray tube and detector.

Using a portable x-ray tube and silicon PiN diode detector, an improved approach to the measurement of arsenic in skin phantoms was demonstrated. Skin phantoms of 8 mm thickness were made from polyester resin, with arsenic concentrations ranging from 0 to 30 microg g(-1). The excitation of characteristic arsenic x-rays was performed with the x-ray tube and K(alpha) x-rays were used as an indicator of arsenic concentration.

A 4 x 500 mm2 cloverleaf detector system for in vivo bone lead measurement.

A 4 x 500 mm2 "cloverleaf" low energy germanium detector array has been assembled for the purpose of in vivo bone lead measurement through x-ray fluorescence. Using 109Cd as an exciting source, results are reported from a leg phantom simulating measurement of lead in a human tibia. For high activity (4.

The importance of a clean face: the effect of different washing procedures on the association of Tamm-Horsfall glycoprotein and other urinary proteins with calcium oxalate crystals.

This study was undertaken to determine whether the use of different washing procedures could explain dissident findings in published studies examining the role of urinary macromolecules in urolithiasis. Calcium oxalate monohydrate (COM) crystals were deposited from or added to the same sieved urine, washed with copious or limited amounts of distilled water, or with methanol, and examined by field emission scanning electron microscopy (FESEM). Demineralized extracts were analysed by SDS-PAGE and Western blotting for Tamm-Horsfall glycoprotein (THG), human serum albumin (HSA), osteopontin (OPN) and prothrombin fragment 1 (PTF1).

Monte Carlo simulations of in vivo K-shell X-ray fluorescence bone lead measurement and implications for radiation dosimetry.

In order to improve measurement precision and decrease minimum detectable limit, recent applications of K-shell X-ray fluorescence (KXRF) bone lead measurement have used shorter source-to-sample (S-S) distances (approximately 0.5 cm) than the traditionally standard values ranging between 2.0 and 3.

In vivo K-shell X-ray fluorescence bone lead measurements in young adults.

The (109)Cd K-shell X-ray fluorescence (XRF) technique was used to measure in vivo tibia lead concentrations of 34 young adults living in the state of Vermont (USA) and the province of New Brunswick (Canada). The subjects ranged in age from 18 to 35 years, and had no known history of elevated lead exposure. Measurement parameters were varied, using the same XRF system for both populations.

Monte Carlo investigations of distance-dependent effects on energy deposition in K-shell x-ray fluorescence bone lead measurement.

Radiation energy deposition results are presented from a Monte Carlo code simulating the lower part of a leg during an in vivo 109Cd K-shell x-ray fluorescence (KXRF) bone lead measurement. The simulations were run for a leg phantom model representing an adult subject, assuming concentrations of 10 microg Pb per gram bone mineral and tracing 500 million photons in each simulation. Trials were performed over a range (0.

Intracrystalline proteins and urolithiasis: a synchrotron X-ray diffraction study of calcium oxalate monohydrate.

Unlabelled: The existence of intracrystalline proteins and amino acids in calcium oxalate monohydrate was demonstrated by X-ray synchrotron diffraction studies. Their presence has implications for the destruction of calcium oxalate crystals formed in the urinary tract and the prevention of kidney stones.

Introduction: Although proteins are present in human kidney stones, their role in stone pathogenesis remains unknown.