RESUMEN
BACKGROUND AND AIM: Determination of skeletal maturity and bone age from cervical vertebrae has been well documented. Most methods described use subjective evaluation of morphological characteristics of cervical vertebrae and may be prone to variability and error. A few objective methods have also been developed, specific for certain populations and genders. The aim of this study was to establish and validate an objective method to determine cervical vertebral bone age from lateral cephalometric radiographs, for Asian South Indian patients of both genders. METHODS: Ninety boys and 90 girls between 9 and 15 years of age were recruited, and their lateral cephalograms were taken. Using measurements made from the third and fourth cervical vertebrae, a formula to determine cervical vertebral bone age was derived using stepwise regression analysis. To validate the formula, a separate sample of 30 boys and 30 girls was chosen, and hand-wrist radiographs and lateral cephalograms were obtained. Cervical vertebral bone age (CVBA) was determined by applying the formula derived. Bone age was also calculated using the Tanner-Whitehouse 3 method. The bone ages determined by both methods were compared to each other and chronological age, using one-way ANOVA, Tukey's post hoc analysis, and Pearson's correlation coefficient. RESULTS: The formulae derived in the current study to determine CVBA differed for both genders. No statistically significant difference was found between CVBA, bone age derived by the Tanner-Whitehouse 3 method, and chronological age for both boys (p value = 0.425) and girls (p value = 0.995). A moderate to strong positive correlation was found between CVBA, bone age, and chronological age. CONCLUSION: The formulae derived in this study were validated and are reliable for objectively determining cervical vertebral bone age and skeletal maturation from lateral cephalograms for Asian South Indian patients of both genders.
Asunto(s)
Determinación de la Edad por el Esqueleto , Vértebras Cervicales , Adolescente , Cefalometría , Vértebras Cervicales/diagnóstico por imagen , Niño , Femenino , Humanos , Masculino , Análisis de Regresión , Reproducibilidad de los ResultadosRESUMEN
A microwave-assisted steam distillation (MASD) sample preparation technique for extracting chlorophenols from solid samples was studied. This open vessel microwave system based study developed as an integrated method since it has incorporated extractive distillation, derivatization and on-line enrichment. Gas chromatography (GC) with electron-capture detection was used for the analysis. The study involved optimization of MASD parameters and on-line enrichments using spiked solid samples. MASD achieved recoveries for spiked soil samples in the range of 94-101% within 20min with a collection of only 20ml distillate facilitating on-line enrichment. Some real samples were analyzed that included soil, wood, leather, textiles, dyes and certified reference materials of soil and wood samples. Limit of detection values of 12ng/g for pentachlorophenol and 194ng/g for monochlorophenol were found. Recoveries of 96.6% in the case of soil certified reference material (CRM) with RSD 2.7% and 80.6% in the case of wood CRM with RSD 3.3% were observed in this study. MASD studied found to produce very clean extracts in comparison to reference techniques.
Asunto(s)
Fraccionamiento Químico/instrumentación , Clorofenoles/aislamiento & purificación , Fraccionamiento Químico/métodos , Cromatografía de Gases , Colorantes/química , Microondas , Sistemas en Línea , Contaminantes del Suelo/análisis , Textiles/análisis , Madera/químicaRESUMEN
Open-vessel focused microwave (FMW) extraction with a purely aqueous carbonate solution was used for the extraction of chlorophenols from various solid matrices. After SPE on C18-bonded silica, the analytes were determined as such by LC-UV or, as their acetyl derivatives, by GC-ECD. The FMW aqueous extraction is efficient and rapid and no organic solvents are used. PCP was detected in several solid samples, with recoveries of 101-115% (RSD, 2-4%) relative to Soxhlet extraction. Similar recoveries were obtained for the other chlorophenols for spiked samples.
Asunto(s)
Clorofenoles/aislamiento & purificación , Cromatografía de Gases , Cromatografía Liquida , Microondas , Animales , Carbonatos , Papel , Contaminantes del Suelo/análisis , Textiles/análisis , MaderaRESUMEN
Extracellular fluid protein (ECFP) of Streptomyces species SS07 has been used to reduce water soluble azo dyes and the carcinogenic amines released have been compared with that from chemical reduction. The effect of temperature, pH and contact time on the recovery of amines using ECFP was studied. The ECFP releases carcinogenic amines at a pH of 9.2 and a temperature of 37 degrees C for a contact period of 24 h. The reduction products were analyzed with HPLC and their structures confirmed by LC-MS and GC-MS. It was observed that both the ECFP and chemical reduction methods released similar type of amine products. In the case of dye samples, compared to chemical reduction, 5-20% increase in the release of carcinogenic amines by ECFP was observed. The percentage of amine products released by chemical reduction was higher for leather garment samples compared to ECFP treatment.
Asunto(s)
Aminas/análisis , Compuestos Azo/química , Carcinógenos/análisis , Streptomyces/química , Cromatografía Líquida de Alta Presión/métodos , Espectrofotometría UltravioletaRESUMEN
Hexavalent chromium detection in the presence of a high load of colourants without any false positive and in-procedure oxidation of Cr(III) is an important area of study. Colourants are a class of interfering substances in many spectroscopic analyses and chromatographic separations and detection. A purification method using an on-line dialysis technique for ion chromatography (IC) has been developed to remove water-soluble anionic dyes and particulate colourants and other substances to facilitate Cr(VI) quantification and the method is discussed. The dialysis was optimized with Cr(VI) standard solutions for quantification. The efficacy of the procedure for the removal of anionic dyes and detection of Cr(VI) was checked with a Cr(VI) spiked synthetic preparation containing a water-soluble dye and trivalent chromium. Soluble Cr(VI) extracted with organic dyes from environmental samples was analyzed. The method has a detection limit of 5 microg/l, recovery rate of 100% and analysis time less than 20 min.
Asunto(s)
Cromatografía Liquida/métodos , Cromo/análisis , Diálisis , Reproducibilidad de los ResultadosRESUMEN
Analysis of carcinogenic substances is a high-priority area. Carcinogenic arylamines draw the analyst's attention because dyes and pigments are in production and used in large volumes. Identification of carcinogenic isomers of arylamines employing micellar electrokinetic chromatography (MEKC), a mode of capillary electrophoresis was studied as it offers better scope for separation science. Mixed micellar modes of MEKC techniques were employed to achieve acceptable analyses. Success of this analytical method was proved by real-sample analysis, which confirmed that this is a promising technique for the arylamine species.