238 research outputs found
Blood cyanide determination in two cases of fatal imtoxication: comparison between headspace gas chromatography and a spectrophotometric method
Blood samples of two cases were analyzed preliminarily by a classical spectrophotometric method (VIS) and by an automated headspace gas chromatographic method with nitrogen-phosphorus detector (HS-GC \u2044 NPD). In the former, hydrogen cyanide (HCN) was quantitatively
determined by measuring the absorbance of chromophores forming as a result of interaction with chloramine T. In the automated HS-GC \u2044NPD method, blood was placed in a headspace vial, internal standard (acetonitrile) and acetic acid were then added. This resulted in cyanide being liberated as HCN. The spectrophotometric (VIS) and HS-GC\u2044NPD methods were validated on postmortem blood samples fortified with potassium cyanide in the ranges 0.5\u201310 and 0.05\u20135 lg \u2044 mL, respectively. Detection limits were 0.2 lg \u2044mL for VIS and 0.05 lg \u2044mL for HS-GC\u2044NPD. This work shows that results obtained by means of the two procedures were insignificantly different and that they compared favorably. They are suitable for rapid diagnosis of cyanide in postmortem cases
Quali-Quantitative Analysis by LC/DAD and GPC of the Polyphenols ofUva Di Troia Canosina Grape Seeds for the Development of an IndustrialNutraceutical Product
The quali-quantitative determination of the principal components of "uva di Troia canosina" seed extracts by LC/ DAD analysis and the optimization of the extraction and purification processes for the development of an industrial nutraceutical product, are described. Two different fractions of seeds collected at different stages of fermentation were compared: "Tesi" 2 when there is a spontaneous stratification of the seeds at the bottom of the recipient and "Tesi" 4 at the end of fermentation. Percolation was applied and compared to maceration and the purification step carefully evaluated to obtain extracts free of contaminant species endowed with polyphenolic content comparable to commercial preparations such as Leucoselect® (Indena, SpA, Italy), Vitis Vinifera extract 95% (seeds), Vitis Vinifera dry extract 95%, Biovin grape seed and vinasse extract. (Farmalabor, Italy). In particular, "Tesi" 2 extract obtained by percolation and purified with a LLE extraction with ethyl acetate showed a polyphenolic content similar to Leucoselect®. From the quantitative analyses it was evident, as expected, that "Tesi"2 has a higher polyphenolic content compared to "Tesi" 4, because during vinification the must extracts polyphenols from the seeds. On the other hand, "Tesi" 4 is particularly convenient since it is easily obtained and very economical, being a waste product. The residual content of organic solvents (ethanol and ethyl acetate) and water was assessed in the grape extracts according to ICH rules by means respectively of HS/GC and Karl Fisher titration in order to meet the requirements for commercialization. Furthermore, the high molecular weight polyphenolic fraction of our extracts was investigated through gel permeation chromatography (GPC) and compared to that of Leucoselect®
Comparison between Lc/Uv and Gc/Fid techniques in determining N,NDimethylacetamide(Dma) in diacerein
Objectives: The aim of this work was the quantitative determination of N,N-Dimethylacetamide (DMA) as crystallization solvent in samples of Diacerein. DMA is commonly used as a solvent in the chemical, agricultural and pharmaceutical industries. However, in order to ensure product quality and to protect patients from the potentially toxic properties, the substances used as active ingredients in therapeutic drugs should not contain high levels of residual solvents. Methods: LC is commonly used in the pharmaceutical industry to check DMA in pharmaceutical products, but in this work we were interested in validating and comparing LC/UV and GC/FID techniques for determining the presence of DMA in Diacerein Results: Both methods showed good linearity, precision and accuracy with comparable LOD and LOQ. Conclusion: The GC method, however, since it uses DMSO as an internal standard, has higher analytical versatility, thus allowing the qualitative and quantitative determination of DMA at lower levels than those obtained with LC
Validation Study of Analysis of 1-Phenyl-2-Propanone in Illicit Methamphetamine Samples by Dynamic Headspace Gas Chromatography Mass Spectrometry
A new method based on dynamic headspace sampling (DHS) coupled to GC/MS analysis was developed, optimized and validated for the analysis of 1-phenyl-2-propanone (P2P) in illicit methamphetamine (MAMP) samples. The DHS parameters were investigated to reach the sensitivity suitable for this kind of analysis. The method showed of a good specificity, linearity, accuracy, precision and robustness. The analysis of ten MAMP samples seized by the judicial authority was carried out. P2P was found in all the seizure, confirming that P2P is the starting compound of the synthesis of amphetamines
Revised North Star Ambulatory Assessment for Young Boys with Duchenne Muscular Dystrophy
The advent of therapeutic approaches for Duchenne muscular dystrophy (DMD) has highlighted the need to identify reliable outcome measures for young boys with DMD. The aim of this study was to develop a revised version of the North Star Ambulatory Assessment (NSAA) suitable for boys between the age of 3 and 5 years by identifying age appropriate items and revising the scoring system accordingly. Using the scale in 171 controls between the age of 2.9 and 4.8 years, we identified items that were appropriate at different age points. An item was defined as age appropriate if it was completed, achieving a full score, by at least 85% of the typically developing boys at that age. At 3 years (±3months) there were only 8 items that were age appropriate, at 3 years and 6 months there were 13 items while by the age of 4 years all 17 items were appropriate. A revised version of the scale was developed with items ordered according to the age when they could be reliably performed. The application of the revised version of the scale to data collected in young DMD boys showed that very few of the DMD boys were able to complete with a full score all the age appropriate items. In conclusion, our study suggests that a revised version of the NSAA can be used in boys from the age of 3 years to obtain information on how young DMD boys acquire new abilities and how this correlates with their peers
Taxonomic Identification of Hallucinogenic Mushrooms Seized on the Illegal Market Using a DNA-Based Approach and LC/MS-MS Determination of Psilocybin and Psilocin
The taxonomic identification of mushrooms suspected to contain hallucinogenic active principles was carried out
using a DNA-based approach, thus highlighting the usefulness of this approach in the forensic identification of illegal
samples also when they are difficult to identify because the morphologic identification is prevented, due to the bad
conservation of the vegetable material.
To confirm the presence of the illegal active principles, the optimization of a LC/MS-MS method for the qualitativequantitative
analysis of psilocin and psilocybin in mushroom samples seized by the judicial authority is described.
For the quantitative determination it was necessary to identify and synthesize a proper internal standard (IS, i.e.,
5-hydroxy-N,N-diethyltryptamine), endowed with chromatographic features suitable for the analysis of the active
principles. LC/MS-MS analysis evidenced that the amount of psilocybin ranged from 0.5 to 1.4% while that of psilocin
from 1.3 to 2.5% (w/w), confirming literature data. The concentration of psilocin was higher in the cap and in the distal
part of the stem (near to the soil) than in the part of the stem proximal to the cap. On the other hand the concentration
of psilocybin was higher in the cap and in the proximal part, being lower in the distal part of the stem
Determination of 6-Monoacetyl-Morphine (6-MAM) in Brain Samples from Heroin Fatalities
Objective: Post-mortem brain samples from 15 deceased patients whose death was heroin related, were analyzed to determine 6-monoacetyl-morphine (6-MAM) concentrations. The samples belonged to people died between 2008 and 2014. The first eight samples were also analyzed in 2012 to determine only morphine and codeine levels. Method: A GC/MS method was studied in order to enhance sensitivity, thus helping the determination of 6-MAM whose detection is in most cases difficult because of the complexity of the biological matrix. The analytical method was validated using deuterated internal standards (IS-D3, morphine-D3 and codeine-D3) and it showed adequate specificity, linearity, LOD, LOQ precision and accuracy for the determination of the analyte of interest. Results: 6-MAM was evidenced only in the more recent samples, thus pointing out its low stability. Its concentration ranged from 15.6 to 28.9 ng/g. Morphine and codeine was also determined and a comparison was carried out between the blood and the brain levels of the three analytes. Moreover a parallel was established between the concentrations of morphine and codeine found in the brain in 2012 and 2015. Conclusion: 6-MAM determination in the brain is particularly important when discriminating between morphine assumption and heroin abuse. In fact in the cases in which it is not detectable in the blood it can be present in the brain. It was noticed that the concentrations of morphine found in the brain in 2015 are higher respect to the levels of 2012; a possible explanation could be that 6-MAM originally present in the brain has hydrolyzed to morphine, thus increasing its levels
Correction : Long term natural history data in ambulant boys with Duchenne muscular dystrophy : 36-month changes
The 6 minute walk test has been recently chosen as the primary outcome measure in international multicenter clinical trials in Duchenne muscular dystrophy ambulant patients. The aim of the study was to assess the spectrum of changes at 3 years in the individual measures, their correlation with steroid treatment, age and 6 minute walk test values at baseline. Ninety-six patients from 11 centers were assessed at baseline and 12, 24 and 36 months after baseline using the 6 minute walk test and the North Star Ambulatory Assessment. Three boys (3%) lost the ability to perform the 6 minute walk test within 12 months, another 13 between 12 and 24 months (14%) and 11 between 24 and 36 months (12%). The 6 minute walk test showed an average overall decline of 1215.8 (SD 77.3) m at 12 months, of 1258.9 (SD 125.7) m at 24 months and 12104.22 (SD 146.2) m at 36 months. The changes were significantly different in the two baseline age groups and according to the baseline 6 minute walk test values (below and above 350 m) (p<0.001). The changes were also significantly different according to steroid treatment (p\u200a=\u200a0.01). Similar findings were found for the North Star Ambulatory Assessment. These are the first 36 month longitudinal data using the 6 minute walk test and North Star Ambulatory Assessment in Duchenne muscular dystrophy. Our findings will help not only to have a better idea of the progression of the disorder but also provide reference data that can be used to compare with the results of the long term extension studies that are becoming available
Superconducting pairing symmetry on the extended Hubbard model in the presence of the Rashba-type spin-orbit coupling
In order to study the pairing symmetry in non-centrosymmetric
superconductors, we solve the linearized Eliashberg's equation on the
two-dimensional extended Hubbard model in the presence of the Rashba-type
spin-orbit coupling (RSOC) within the random phase approximation. In the
presence of the RSOC, three types of pairing symmetries appear in the phase
diagram with respect to the on-site Coulomb repulsion U and off-site one V.
Each of pairing symmetries is admixture of spin-singlet and -triplet ones. On
the basis of analytical study, it is found that the admixture of spin-singlet
and -triplet components depends on not only the predominant pairing symmetry
but also dispersion relation and pairing interaction.Comment: 11 pages, 12 figure
Biochemical characterization and low-resolution SAXS shape of a novel GH11 exo-1,4-β-xylanase identified in a microbial consortium
Biotechnologies that aim to produce renewable fuels, chemicals, and bioproducts from residual ligno(hemi)cellulosic biomass mostly rely on enzymatic depolymerization of plant cell walls (PCW). This process requires an arsenal of diverse enzymes, including xylanases, which synergistically act on the hemicellulose, reducing the long and complex xylan chains to oligomers and simple sugars. Thus, xylanases play a crucial role in PCW depolymerization. Until recently, the largest xylanase family, glycoside hydrolase family 11 (GH11) has been exclusively represented by endo-catalytic β-1,4- and β-1,3-xylanases. Analysis of a metatranscriptome library from a microbial lignocellulose community resulted in the identification of an unusual exo-acting GH11 β-1,4-xylanase (MetXyn11). Detailed characterization has been performed on recombinant MetXyn11 including determination of its low-resolution small angle Xray scattering (SAXS) molecular envelope in solution. Our results reveal that MetXyn11 is a monomeric globular enzyme that liberates xylobiose from heteroxylans as the only product. MetXyn11 has an optimal activity in a pH range from 6 to 9 and an optimal temperature of 50 oC. The enzyme maintained above 65% of its original activity in the pH range 5 to 6 after being incubated for 72 h at 50 oC. Addition of the enzyme to a commercial enzymatic cocktail (CelicCtec3) promoted a significant increase of enzymatic hydrolysis yields of hydrothermally pretreated sugarcane bagasse (16% after 24 h of hydrolysis)
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