Methacholine challenge studies are often conducted to diagnose asthma in patients with mild or intermittent respiratory symptoms when screening spirometry results are normal. We hypothesized that in patients with increased nonspecific bronchial hyperreactivity (NSB-HR), gas trapping might be present and that this information could be a factor in clinical decision making. To assess the relations...

We read with extreme interest the recently published work by O’Donnell and colleagues (May 2010). 1 Comparing lung volumes obtained using different techniques in a sample of patients with severe airfl ow limitation, the authors conclude that plethysmography systematically overestimates lung volumes with regard to gas dilution and thoracic imaging techniques. We believe it is meritorious to asse...

In this simple thin-layer chromatographic (TLC) technique for evaluating porphyrin excretion, porphyrins are extracted from urine or feces, then separated on silica-gel TLC plates. The distinct porphyrin bands are observed by viewing the plates under long-wave fluorescent light. Positive screening tests can readily be confirmed or rejected, and a more comprehensive investigation confidently und...

This study describes a method for off-line coupling of thin-layer chromatography (TLC) with electron impact ionization (El)-mass spectrometry for routine determination of pesticides in toxicology and forensic medicine. Six TLC solvent systems are described for 151 different pesticides, and 8-peak mass-spectra generated from full El mass spectra are listed.

Amino acid, carbohydrate, and lipid components of cell walls of Brucella abortus strain 19A (low virulence) and strain 2308 (high virulence) were compared by thin layer chromatography (TLC) and by use of an amino acid analyzer. A total of 15 amino acids were detected by both chromatographic methods. Each amino acid was present in greater amounts in strain 2308 than in strain 19A when equal amou...

In this study, we aim to develop methods to detect trace Cannabis in cooked food. We compared the use of chemical method and DNA analysis. Firstly, the Cannabis materials were identified by the macroscopic features, presumptive colortesting, and then confirmed by TLC analysis in hexane-dioxane-methanol (7:2:1). This solvent system gave the best resolution for cannabinoid separation in our hands...

We measured pulmonary function, responses to exercise and oxygen saturation (So2) at rest, and also before and during sleep in 24 patients with cystic fibrosis in a varying degree of severity. The pulmonary function indices analysed were forced expiratory volume in one second (FEV1), total lung capacity (TLC), measured by body plethysmography (TLC box) and Helium dilution (TLC He), residual vol...

The state-based formal methods B and TLA share the common base of predicate logic, arithmetic and set theory. However, there are still considerable differences, such as the way to specify state transitions, the different approaches to typing, and the available tool support. In this paper, we present a translation from B to TLA to validate B specifications using the model checker TLC. The transl...

Sudan I is a carcinogenic compound containing an azo group that has been illegally utilized as an adulterant in food products to impart a bright red color to foods. In this paper, we develop a facile lab-on-a-chip device for instant, ultra-sensitive detection of Sudan I from real food samples using plasmonics-enhanced diatomaceous thin film, which can simultaneously perform on-chip separation u...