966 resultados para PRECISION


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Most current methods for adult skeletal age-at-death estimation are based on American samples comprising individuals of European and African ancestry. Our limited understanding of population variability hampers our efforts to apply these techniques to various skeletal populations around the world, especially in global forensic contexts. Further, documented skeletal samples are rare, limiting our ability to test our techniques. The objective of this paper is to test three pelvic macroscopic methods (1-Suchey-Brooks; 2- Lovejoy; 3- Buckberry and Chamberlain) on a documented modern Spanish sample. These methods were selected because they are popular among Spanish anthropologists and because they never have been tested in a Spanish sample. The study sample consists of 80 individuals (55 ♂ and 25 ♀) of known sex and age from the Valladolid collection. Results indicate that in all three methods, levels of bias and inaccuracy increase with age. The Lovejoy method performs poorly (27%) compared with Suchey-Brooks (71%) and Buckberry and Chamberlain (86%). However, the levels of correlation between phases and chronological ages are low and comparable in the three methods (< 0.395). The apparent accuracy of the Suchey-Brooks and Buckberry and Chamberlain methods is largely based on the broad width of the methods" estimated intervals. This study suggests that before systematic application of these three methodologies in Spanish populations, further statistical modeling and research into the co-variance of chronological age with morphological change is necessary. Future methods should be developed specific to various world populations, and should allow for both precision and flexibility in age estimation.

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This paper reports the method development for the simultaneous determination of methylmercury MeHgþ) and inorganic mercury (iHg) species in seafood samples. The study focused on the extraction and quantification of MeHgþ (the most toxic species) by liquid chromatography coupled to on-line UV irradiation and cold vapour atomic fluorescence spectroscopy (LC-UV-CV-AFS), using HCl 4 mol/L as the extractant agent. Accuracy of the method has been verified by analysing three certified reference materials and different spiked samples. The values found for total Hg and MeHgþ for the CRMs did not differ significantly from certified values at a 95% confidence level, and recoveries between 85% and 97% for MeHgþ, based on spikes, were achieved. The detection limits (LODs) obtained were 0.001 mg Hg/kg for total mercury, 0.0003 mg Hg/kg for MeHgþ and 0.0004 mg Hg/kg for iHg. The quantification limits (LOQs) established were 0.003 mg Hg/kg for total mercury, 0.0010 mg Hg/kg for MeHgþ and 0.0012 mg Hg/kg for iHg. Precision for each mercury species was established, being 12% in terms of RSD in all cases. Finally, the developed method was applied to 24 seafood samples from different origins and total mercury contents. The concentrations for Total Hg, MeHg and iHg ranged from 0.07 to 2.33, 0.003-2.23 and 0.006-0.085 mg Hg/kg, respectively. The established analytical method allows to obtain results for mercury speciation in less than 1 one hour including both, sample pretreatment and measuring step.

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One still wonders today at the anatomical precision with which various ancient authors, like Homer, depict the inner body. How was it possible to get such a precise knowledge, at a period when medicine was not particularly famous for its scientific achievements? The history of the beginnings of western anatomy reveals a surprising variety: its progress, until the tremendous technical fulfilments of contemporary anatomical imaging, has been neither linear, nor spontaneous, nor even necessary. Before becoming one of the epistemological bedrocks of medicine, its history reveals itself filled with accidents, ruptures, contingencies, and actors who contributed to modify its course.

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Per poder desenvolupar un producte farmacèutic és necessari establir un mètode d’anàlisis que permeti determinar i quantificar totes aquelles substàncies que conté, ja sigui referent als principis actius; a les impureses i productes de degradació, conservants, antioxidants,... Grans entitats com la ICH remarquen la importància de validar els mètodes analítics ja que és la via per demostrar que aquell producte compleix les garanties de qualitat prèviament establertes. Així doncs, l’objectiu d’aquest Treball Final de Grau és poder desenvolupar i validar dos mètodes analítics per a la determinació d’aminoàcids i carbohidrats respectivament, d’un producte farmacèutic per cromatografia líquida (HPLC). Per tal de poder concloure que aquell mètode és adequat per la determinació per la qual ha estat desenvolupat, és necessari obtenir resultats que compleixin els criteris d’acceptació corresponents als paràmetres que han de ser avaluats en una validació analítica. Aquests paràmetres són: la precisió, la selectivitat, l’exactitud i la linealitat i el rang. Els resultats d’aquest projecte han demostrat que els dos mètodes desenvolupats són adequats per a la determinació de tres dels principis actius (aminoàcid 1, aminoàcid 2 i carbohidrat 1) que conté el producte farmacèutic d’ús veterinari analitzat; i poden ser validats ja que compleixen els criteris d’acceptació dels paràmetres avaluats que proposa la ICH. El mètode per la determinació de carbohidrats no és vàlid per el carbohidrat 2, ja que durant el desenvolupament es va detectar que una bona part d’aquest passava a carbohidrat 1 (desplaçament de l’equilibri ceto-enòlic que hi ha entre el carbohidrat 1 i el carbohidrat 2 a pHs alts). És per aquest motiu, que es pot concloure que aquest mètode no és vàlid i es recomana seguir investigant per a poder desenvolupar un mètode analític adient.

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In this thesis (TFG) the results of the comparison of three assays for the measurement of AhR ligand activity are exposed. This study was part of a collaborative project aiming at the characterization of the AhR signaling activities of known naturally occurring compounds to explore the potential of using non-toxic compounds to treat inflammatory diseases via oral administration. The first goal of this project was to find an assay able to measure AhR-activity, so the comparison of different assays has been done in order to find the most convenient one according to the efficiency, sensitivity and precision. Moreover, other elements with operational nature such as price, toxicity of components or ease of use has been considered. From the use of compounds known from the literature to be AhR ligands, three assays have been tested: (1) P450-GloTM CYP1A2 Induction/Inhibition assay, (2) quantitative Polymerase Chain Reaction (qPCR) and (3) DR. CALUX® Bioassay. Moreover, a different experiment using the last assay was performed for the study in vivo of the transport of the compounds tested. The results of the TFG suggested the DR. CALUX® Bioassay as the most promising assay to be used for the screening of samples as AhR-ligands because it is quicker, easier to handle and less expensive than qPCR and more reproducible than the CYP1A2 Induction/Inhibition assay. Moreover, the use of this assay allowed having a first idea of which compounds are uptaken by the epithelial barrier and in with direction the transport happens.

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L’objectiu principal d’aquest treball de fi de grau és fer-se càrrec d’una traducció jurídica amb tot el què això implica: documentar-se a través de fonts fiables, emprar les eines adequades, lliurar-lo dins el termini establert, entre d’altres. En aquest cas, és una traducció de les lleis que regulen les adopcions a l’Índia. A més, en aquest treball també s’explica breument el dret civil a Catalunya i es compara amb el de l’Índia, ja que es basen en idees molt diferents. Aquests tipus de traduccions exigeixen precisió i claredat perquè els conceptes i les estructures sintàctiques acostumen a ser molt complexes. A continuació, hi ha detallat cada pas que s’ha seguit per tal d’assolir l’objectiu principal.

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The visual angle that is projected by an object (e.g. a ball) on the retina depends on the object's size and distance. Without further information, however, the visual angle is ambiguous with respect to size and distance, because equal visual angles can be obtained from a big ball at a longer distance and a smaller one at a correspondingly shorter distance. Failure to recover the true 3D structure of the object (e.g. a ball's physical size) causing the ambiguous retinal image can lead to a timing error when catching the ball. Two opposing views are currently prevailing on how people resolve this ambiguity when estimating time to contact. One explanation challenges any inference about what causes the retinal image (i.e. the necessity to recover this 3D structure), and instead favors a direct analysis of optic flow. In contrast, the second view suggests that action timing could be rather based on obtaining an estimate of the 3D structure of the scene. With the latter, systematic errors will be predicted if our inference of the 3D structure fails to reveal the underlying cause of the retinal image. Here we show that hand closure in catching virtual balls is triggered by visual angle, using an assumption of a constant ball size. As a consequence of this assumption, hand closure starts when the ball is at similar distance across trials. From that distance on, the remaining arrival time, therefore, depends on ball's speed. In order to time the catch successfully, closing time was coupled with ball's speed during the motor phase. This strategy led to an increased precision in catching but at the cost of committing systematic errors.

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Reversed phase liquid chromatography (RPLC) coupled to mass spectrometry (MS) is the gold standard technique in bioanalysis. However, hydrophilic interaction chromatography (HILIC) could represent a viable alternative to RPLC for the analysis of polar and/or ionizable compounds, as it often provides higher MS sensitivity and alternative selectivity. Nevertheless, this technique can be also prone to matrix effects (ME). ME are one of the major issues in quantitative LC-MS bioanalysis. To ensure acceptable method performance (i.e., trueness and precision), a careful evaluation and minimization of ME is required. In the present study, the incidence of ME in HILIC-MS/MS and RPLC-MS/MS was compared for plasma and urine samples using two representative sets of 38 pharmaceutical compounds and 40 doping agents, respectively. The optimal generic chromatographic conditions in terms of selectivity with respect to interfering compounds were established in both chromatographic modes by testing three different stationary phases in each mode with different mobile phase pH. A second step involved the assessment of ME in RPLC and HILIC under the best generic conditions, using the post-extraction addition method. Biological samples were prepared using two different sample pre-treatments, i.e., a non-selective sample clean-up procedure (protein precipitation and simple dilution for plasma and urine samples, respectively) and a selective sample preparation, i.e., solid phase extraction for both matrices. The non-selective pretreatments led to significantly less ME in RPLC vs. HILIC conditions regardless of the matrix. On the contrary, HILIC appeared as a valuable alternative to RPLC for plasma and urine samples treated by a selective sample preparation. Indeed, in the case of selective sample preparation, the compounds influenced by ME were different in HILIC and RPLC, and lower and similar ME occurrence was generally observed in RPLC vs. HILIC for urine and plasma samples, respectively. The complementary of both chromatographic modes was also demonstrated, as ME was observed only scarcely for urine and plasma samples when selecting the most appropriate chromatographic mode.

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Humans like some colours and dislike others, but which particular colours and why remains to be understood. Empirical studies on colour preferences generally targeted most preferred colours, but rarely least preferred (disliked) colours. In addition, findings are often based on general colour preferences leaving open the question whether results generalise to specific objects. Here, 88 participants selected the colours they preferred most and least for three context conditions (general, interior walls, t-shirt) using a high-precision colour picker. Participants also indicated whether they associated their colour choice to a valenced object or concept. The chosen colours varied widely between individuals and contexts and so did the reasons for their choices. Consistent patterns also emerged, as most preferred colours in general were more chromatic, while for walls they were lighter and for t-shirts they were darker and less chromatic compared to least preferred colours. This meant that general colour preferences could not explain object specific colour preferences. Measures of the selection process further revealed that, compared to most preferred colours, least preferred colours were chosen more quickly and were less often linked to valenced objects or concepts. The high intra- and inter-individual variability in this and previous reports furthers our understanding that colour preferences are determined by subjective experiences and that most and least preferred colours are not processed equally.

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The use of the life history calendar (LHC) or the event history calendar as tools for collecting retrospective data has received increasing attention in many fields of social science and medicine. However, little research has examined the use of this method with web-based surveys. In this study, we adapted this method to an on-line setting to collect information about young adults' life histories, sexual behaviors, and substance use. We hypothesized that the LHC method would help respondents to date sensitive and non-sensitive events more precisely than when using a conventional questionnaire. We conducted an experimental design study comparing university students' responses to an on-line LHC and a conventional on-line question list. A test-retest design in which the respondents completed the survey again two weeks later was also applied to test the precision and reliability of the participants' dating of events. The results showed that whereas the numbers of sensitive and non-sensitive events were generally similar for the two on-line questionnaires, the responses obtained with the LHC were more consistent across the two administrations. Analyses of the respondents' on-line behavior while completing the LHC confirmed that respondents used the LHC's graphic interface to correct and reedit previous answers, thus decreasing data errors. (C) 2015 Elsevier Ltd. All rights reserved.

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L'adoption de l'IRM dans le parcours diagnostique a déterminé la transition des biopsies aléatoires aux biopsies ciblées vers les lésions visibles à l'imagerie. L'utilisation de logiciels rendant possible la fusion d'images IRM et échographiques permet d'améliorer significativement la précision diagnostique de ces biopsies. De plus, pour déterminer l'éligibilité d'un patient à une thérapie focale, davantage de précision diagnostique est requise au niveau de toute la glande ; par conséquent, des biopsies avec une densité d'échantillonnage plus élevée par voie transpérinéale peuvent être proposées.Les nouvelles techniques de biopsie de la prostate permettent une prise en charge personnalisée grâce à une meilleure caractérisation de l'agressivité et de l'extension locale du cancer de la prostate. The adoption of multiparametric MRI within the diagnostic pathway has allowed urologists to move from random biopsy to targeted biopsy directed towards MR-visible lesions. The use of software for MR to TRUS fusion may enhance the diagnostic accuracy of targeted biopsy. To determine the eligibility for tissue-preserving approaches, further precision is required, and template prostate mapping biopsy may be offered. The employment of novel biopsy techniques provide better characterisation of the disease, and allows a tailored approach to a single subject.

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Screening mammography is the only imaging modality with proved decrease in breast cancer mortality. Ultrasound has been proposed as additional tool for screening. Controversies remain about the real value of sonography in this setting. In Caucasian women with dense breast, sonography improves significantly breast cancer detection, but also increases the false positive cases, biopsies and costs. A careful selection of women who may benefit from additional screening with sonography is mandatory.

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The construction and evaluation of an inexpensive flow photometer for clinical analysis, using a bicolour LED and a phototransistor adapted for tubular flow cell, are described. The instrument presents some new features such as: automatic zero, electronic calibration and peak-hold signal. When compared with a classical photometer, it is simpler and has the advantages of a flow analysis system: lower volumes of reagents and samples, lower levels of contamination, shorter time for analysis and lower analysis costs. The instrument was used in the determination of the constituents in blood samples. The results obtained agree with those obtained by a classical photometer and the precision was better.

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An automatic dispenser based on a flow-injection system used to introduce sample and analytical solution into an inductively coupled plasma mass spectrometer through a spray chamber is proposed. Analytical curves were constructed after the injection of 20 to 750 µL aliquots of a multielement standard solution (20.0 µg L-1 in Li, Be, Al, V, Cr, Mn, Ni, Co, Cu, Zn, As, Se, Sr, Ag, Cd, Ba, Tl, Pb) and the acquisition of the integrated transient signals. The linear concentration range could be extended to ca. five decades. The performance of the system was checked by analyzing a NIST 1643d reference material. Accuracy could be improved by the proper selection of the injected volume. Besides good precision (r.s.d. < 2%), the results obtained with the proposed procedure were closer to the certified values of the reference material than those obtained by direct aspiration or by injecting 125 µL of several analytical solutions and samples.

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One old dream of the chemist in the field of the drug research is to create molecules capable of reaching their target with the precision of a missile. To accomplish it these molecules must have the propriety of distinguishing qualitative differences between healthy and diseased cells. A therapy based on this principle, able of eradicating specifically defective cells, or cells affected by a pathogen has an enormous advantage with the regard to the classical approach in which the cytotoxic drugs merely exploit quantitative biochemical and kinetic differences between abnormal and normal cells. We present in this article a review on the chemical synthesis of analogues of desoxyribonucleotides and on results obtained on the specific and irreversible inhibition of undesired genetic expression using the antisense principle.