A flow injection-pervaporation approach, where the samples – beech or olive leaves – were introduced as slurry, has been used for continuous derivatization hydride generation and separation of ...cadmium prior to determination by atomic absorption spectrometry. The removal of the analyte is achieved with an 1
mol/l HCl
+
16% H
2O
2 aqueous solution with the help of an ultrasound probe acting for 17
min. Thiourea and cobalt were also added to the slurry for kinetic catalysis of hydride generation. A CRM – beech leaves – where the analyte had not been certified but estimated was used for optimisation of the leaching step. The results obtained using direct calibration against aqueous standards demonstrated the reliability of the method. The linear concentration range of the calibration curve was from pg/ml to ng/ml, with a correlation coefficient,
r
2, better than 0.99. The detection and quantification limits were 0.3 and 0.9
ng/ml, respectively. The relative standard deviation for within-laboratory reproducibility was 5.7%. Olive leaves CRM was used for validation.
A fast, selective and sensitive method is here proposed for the analysis of female steroid hormones as conjugated forms (mainly, glucuronides and sulfates). The method has been applied to female ...urine samples to assess the metabolism of these compounds. The method implements an enzymatic hydrolysis (beta-glucuronidase with sulfatase activity) kinetically enhanced by ultrasonic energy in order to generate the free steroid forms. This enables a drastic shortening of the time required for this step as compared with conventional protocols (from 12-18 hours to 30 min). The reaction kinetics of the ultrasound-enhanced hydrolysis was characterized by comparison to that of the conventional protocol. After hydrolysis, the free steroid hormones were isolated and preconcentrated by automated solid-phase extraction and the eluate was subsequently analysed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The target analytes were confirmed and quantified by multiple reaction monitoring (MRM). The detection and quantification limits were within 0.06-0.8 ng mL(-1) and 0.19-2.69 ng mL(-1), respectively. The precision of the method, expressed as intra-day and inter-day variability, ranged between 2.1 and 5.2% and between 4.9 and 8.0%, respectively. A complementary study was carried out to assess the storage conditions of urine samples. This study is crucial in those applications involving metabolic processes as the integrity of the sample has to be preserved.
The effects of dissolved oxygen tension during bacterial growth and acclimation on the cell surface properties and biochemical composition of the bacterial pathogens Escherichia coli O157:H7 and ...Yersinia enterocolitica are characterized. Three experimental techniques are used in an effort to understand the influence of bacterial growth and acclimation conditions on cell surface charge and the composition of the bacterial cell: (i) electrophoretic mobility measurements; (ii) potentiometric titration; and (iii) ATR-FTIR spectroscopy. Potentiometric titration data analyzed using chemical speciation software are related to measured electrophoretic mobilities at the pH of interest. Titration of bacterial cells is used to identify the major proton-active functional groups and the overall concentration of these cell surface ligands at the cell membrane. Analysis of titration data shows notable differences between strains and conditions, confirming the appropriateness of this tool for an overall charge characterization. ATR-FTIR spectroscopy of whole cells is used to further characterize the bacterial biochemical composition and macromolecular structures that might be involved in the development of the net surficial charge of the organisms examined. The evaluation of the integrated intensities of HPO2 − and carbohydrate absorption bands in the IR spectra reveals clear differences between growth protocols. Taken together, the three techniques seem to indicate that the dissolved oxygen tension during cell growth or acclimation can noticeably influence the expression of cell surface molecules and the measurable cell surface charge, though in a strain-dependent fashion.
Cet article a pour objectif de proposer une réflexion visant à améliorer les liens entre la recherche en psychopathologie et la pratique de la psychologie clinique. Dans un premier temps, les auteurs ...analysent ce qui fonde la démarche de l’une et de l’autre. Ils constatent que la première étudie trop souvent des phénomènes psychopathologiques sans suffisamment les envisager sous leurs aspects d’expression courante. Ainsi conçues, ces recherches sont très peu utiles pour guider les pratiques du psychologue clinicien. À son tour, la pratique de la psychologie clinique, a tendance à perpétuer des modes d’intervention qui ne tiennent pas suffisamment compte des apports de travaux validés dont le niveau de preuve est documenté et perfectible. Les auteurs proposent une démarche clinico-théorique dont la rigueur repose sur ses potentialités d’autocorrection permanente. Ils soulignent aussi l’intérêt de dispositifs qui ont pour objectif l’évaluation de corpus de connaissances cliniques et la traduction de ceux-ci dans la pratique (
Evidence Base Medecine, Conférences de Consensus).
This article is an essay aiming to suggest the development of closer links between psychopathology research and the practice of clinical psychology. To start with, the authors analyze the foundations of both research and practice. They note that the former too often studies psychopathological phenomena without sufficiently considering them as they appear in standard practice. Conceived this way, this type of research is of very little clinical use. The latter — the practice of clinical psychology is rooted in interventions, which do not sufficiently take into account scientific validated and reliable evidence. The authors suggest a clinical-theoretical approach, based on permanent operationalisation of subjective and intersubjective phenomena, and self-correcting steps, whether they are matters of research or clinical practice. Finally, they underlie the interest of approaches like those of the
Evidence Base Medicine and Consensus Conferences.
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•Marshall and ITS tests reveal the optimal percentage of copper slag to be used.•The use of copper slag reduces asphalt mix rigidity with RAP.•Asphalt mix with copper slag perform ...better at low rather than high temperatures.•A stiffening effect of fine material appears when copper slag exceeds 15% addition.
Annually, copper production and refining processes of generate large volumes of copper slag, and the disposal of this waste remains a major economic and environmental problem. This annual production causes an increase in the number and volume of landfills, as well as the quantity of slag that backs up landfills, it also produces leachates which contain metals such as Cu, Pb, Hg and SO2. In this research, friction and cohesive qualities of copper slag are exploited, in order to incorporate this slag as aggregate in asphalt mixes containing Reclaimed Asphalt Pavement (RAP). Results demonstrate that the use of copper slag in an addition percentage of 35% is favorable, because flow values increase and stability values decrease. The Marshall Quotient is reduced up to 27%, improving the performance of mixes with RAP and obtaining behavior similar to a traditional mixture. This improvement is also reflected in an 8% increase in the indirect tensile strength, which stands the use of copper slag as a solution in RAP applications with more demanding tensile and fatigue requirements.
In this brief, we studied the endurance properties of an integrated phase-change line cell. The different characteristics typically observed during the endurance lifetime are described. The ...monitoring of the switching parameters of the cell (reset current and threshold voltage) during endurance testing could be correlated with a gradual degradation of the reset switching. The following conclusions were drawn: 1) The reset-switching degradation is closely associated to both an increase of the minimum reset current and a decrease of the obtained reset and set resistances, pointing to material change; 2) the extent of the degradation strongly depends on the reset pulsewidth, and it was found to scale with tm 3/2 , tm being the melting time during reset pulse; however, higher reset currents did not quicken the onset of degradation; and 3) the tm 3/2 dependence together with polarity-dependent endurance tests suggests the contribution of an electrical-field-driven migration mechanism. Based on these insights, the extended endurance lifetime of more than 10 10 cycles could be demonstrated, using short reset pulses, which could be further increased by changing reset polarity before stuck-set failure.
GDSL-type esterase/lipase protein (GELP) genes are crucial in the specialized lipid metabolism, in the responses to abiotic stresses, and in the regulation of plant homeostasis. R. communis is an ...important oilseed crop species that can sustain growth and productivity when exposed to harsh environmental conditions. Herein, we raised the question of whether the GELP gene family could be involved in the acquisition of R. communis tolerance to abiotic stresses during seed germination and seedling establishment. Thus, we used bioinformatics and transcriptomics to characterize the R. communis GELP gene family. R. communis genome possesses 96 GELP genes that were characterized by extensive bioinformatics, including phylogenetic analysis, subcellular localization, exon-intron distribution, the analysis of regulatory cis-elements, tandem duplication, and physicochemical properties. Transcriptomics indicated that numerous RcGELP genes are readily responsive to high-temperature and salt stresses and might be potential candidates for genome editing techniques to develop abiotic stress-tolerant crops.
•R. communis GELP gene family was characterized by bioinformatics and transcriptomics.•R. communis genome possesses 96 GELP genes (GDSL-like Lipase/Acylhydrolase domain).•The majority of RcGELP genes are responsive to high-temperature and/or salt stress.•GELP genes are potential candidates to address stress-related agronomic crop issues.•Introduction.
Superheated hexane extraction has been tested for obtaining fatty acids from grape seed and compared with conventional Soxhlet and hot hexane extractions. Seeds from grape residues from a winery were ...dried for 46
h at 105
°C, milled and sieved by particle size (
d
<
0.42
mm, 0.42
<
d
<
0.84
mm and
d
>
0.84
mm). An optimization study of influential variables on superheated hexane extraction (namely extraction time, temperature, pression, particle size and sample amount) was carried out by a multivariate approach. All the extracts were concentrated in a rotary evaporator and dried by adding 1
g of Na
2SO
4. Then, 2
ml of the dried extract were subjected to reaction with 1
ml of a 0.5
M solution of sodium methylate in methanol to obtain fatty acid methyl esters (FAMEs). After derivatization, FAMEs were quantified by GC-FID. The results show that the optimal conditions for superheated hexane extraction are: time extraction, 10
min; temperature, 80
°C; pressure, 40
bar; particle size,
d
<
0.42
mm; amount of sample, 0.4
g. Under these conditions, around 84% of the fatty acids (out of the amount obtained by Soxhlet extraction) is extracted. Comparison with Soxhlet and hot hexane extractions showed that the percentages of FAMEs are similar in all the extracts and they agree with the data in the bibliography.
A continuous ultrasound-assisted approach to enhance the extraction of nine haloacetic acids (HAAs) from vegetables with
in situ derivatization to methyl esters for their gas chromatography (GC) ...analysis is presented. The optimization of simultaneous extraction (using acidic methanol as extractant) and derivatization enabled the completion of both steps in 15
min. Ultrasound assistance has proved to enhance both linked steps, which results in a considerable shortening of the overall analysis time (
i.e. 552.1 and 552.2 EPA methods for analysis of these compounds in drinking water require 1 and 2
h, respectively, only for derivatization). After sample preparation, the esterified HAAs were isolated by liquid–liquid extraction with
n-hexane and analysed by GC–electron capture detection. The proposed method is an interesting alternative to present methods for the determination of HAAs in vegetable foods. This is an area unjustifiably forgotten by reference laboratory organisms as proved by the absence of official methods for analysis of the target compounds in these samples. The proposed method can be applied to the analysis of HAAs in any solid sample after optimization of the main variables involved in the extraction–derivatization step.
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