Quantitative performance of a quadrupole-orbitrap-MS in targeted LC-MS determinations of small molecules.

High-resolution mass spectrometry (HRMS) has been associated with qualitative and research analysis and QQQ-MS with quantitative and routine analysis. This view is now challenged and for this reason, we have evaluated the quantitative LC-MS performance of a new high-resolution mass spectrometer (HRMS), a Q-orbitrap-MS, and compared the results obtained with a recent triple-quadrupole MS (QQQ-MS). High-resolution full-scan (HR-FS) and MS/MS acquisitions have been tested with real plasma extracts or pure standards. Limits of detection, dynamic range, mass accuracy and false positive or false negative detections have been determined or investigated with protease inhibitors, tyrosine kinase inhibitors, steroids and metanephrines. Our quantitative results show that today's available HRMS are reliable and sensitive quantitative instruments and comparable to QQQ-MS quantitative performance. Taking into account their versatility, user-friendliness and robustness, we believe that HRMS should be seen more and more as key instruments in quantitative LC-MS analyses. In this scenario, most targeted LC-HRMS analyses should be performed by HR-FS recording virtually "all" ions. In addition to absolute quantifications, HR-FS will allow the relative quantifications of hundreds of metabolites in plasma revealing individual's metabolome and exposome. This phenotyping of known metabolites should promote HRMS in clinical environment. A few other LC-HRMS analyses should be performed in single-ion-monitoring or MS/MS mode when increased sensitivity and/or detection selectivity will be necessary.

Facilitar la teoría de la mente en niños con alteraciones del lenguaje

The ability to recognize mental states in oneself and others, or the theory of mind, has been a widely studied topic in last years. Traditionally, these studies have focused on the understanding of false belief, one of the most important milestones in its development. Studies conducted with children with language difficulties suggest that they have a delay in false belief acquisition. On the other hand, numerous studies have established a relationship between the understanding of false belief and language skills. In particular, it has been suggested that training based in labelling objects with double perspective facilitates the understanding of false belief. The aim of the present study is to test the effect of the structuration level of labelling training in a group of children with difficulties in language development. A total of 14 children, aged between 58 and 107 months, were trained in 3 sessions, and a pre-test and a post-test were administered to evaluate the effects of the training. The results confirm a delay in false belief understanding in children with developmental language difficulties, and suggest that the structured labelling training is effective to improve this understanding

La Relación del lenguaje con la teoría de la mente en edad escolar

In the past years a considerable amount of research has been carried out on the development of theory of mind (ToM) reporting that language and ToM performance are correlated. However it is less clear what aspect of language is related with ToM development. Some studies show a greater influence of semantics aspects, whereas others suggest that sentential complement sentences, a specific aspect of syntax, are crucial for false belief understanding (FB). Yet others argue that pragmatic abilities correlate with FB understanding. The aim of this study is investigate, on the one side, the development of ToM between the ages of 6 and 8 and on the other side, the relationship between some aspects of language and the ToM improvement. Several ToM tasks were administrated to evaluate children’s performance at two different ages (60 participants aged 6 and 8 years) and four tasks to assess language abilities. The results show a significant increase in the understanding of the mind between the ages of 6 and 8. Furthermore, results reveal a significant relationship between syntax and tasks that require FB understanding, while pragmatics is more strongly associated with tasks that involve more complex socio-cognitive understandings

Ilustração da influência da razão de aquecimento nos resultados de termogravimetria

The effects of the heating rate on a TG curve of a sample have been widely discussed in the literature. This paper shows the influence of heating rate (beta) in thermogravimetry results when stoichiometry determinations are studied. For this purpose the compound Sm(CH3SO3)3.2(3-picNO) was considered beta of 2,5; 5; 10; 20 and 40°C min-1 in dynamic air atmosphere were obtained. The results are in agreement with proposed stoichiometry for beta equal to 2,5 and 5°C min-1. However, using a higher beta the same results were not obtained resulting in false stoichiometry determinations.

Methods to test gas tightness of packages

One of the primary goals for food packages is to protect food against harmful environment, especially oxygen and moisture. The gas transmission rate is the total gas transport through the package, both by permeation through the package material and by leakage through pinholes and cracks. The shelf life of a product can be extended, if the food is stored in a gas tight package. Thus there is a need to test gas tightness of packages. There are several tightness testing methods, and they can be broadly divided into destructive and nondestructive methods. One of the most sensitive methods to detect leaks is by using a non destructive tracer gas technique. Carbon dioxide, helium and hydrogen are the most commonly used tracer gases. Hydrogen is the lightest and the smallest of all gases, which allows it to escape rapidly from the leak areas. The low background concentration of H2 in air (0.5 ppm) enables sensitive leak detection. With a hydrogen leak detector it is also possible to locate leaks. That is not possible with many other tightness testing methods. The experimental work has been focused on investigating the factors which affect the measurement results with the H2leak detector. Also reasons for false results were searched to avoid them in upcoming measurements. From the results of these experiments, the appropriate measurement practice was created in order to have correct and repeatable results. The most important thing for good measurement results is to keep the probe of the detector tightly against the leak. Because of its high diffusion rate, the HZ concentration decreases quickly if holding the probe further away from the leak area and thus the measured H2 leaks would be incorrect and small leaks could be undetected. In the experimental part hydrogen, oxygen and water vapour transmissions through laser beam reference holes (diameters 1 100 μm) were also measured and compared. With the H2 leak detector it was possible to detect even a leakage through 1 μm (diameter) within a few seconds. Water vapour did not penetrate even the largest reference hole (100 μm), even at tropical conditions (38 °C, 90 % RH), whereas some O2 transmission occurred through the reference holes larger than 5 μm. Thus water vapour transmission does not have a significant effect on food deterioration, if the diameter of the leak is less than 100 μm, but small leaks (5 100 μm) are more harmful for the food products, which are sensitive to oxidation.

Ensaio de proficiência para análise de ditiocarbamatos em polpa de banana

A proficiency assay of the determination of dithiocarbamate pesticide residues in banana was carried out. Fourteen laboratories participated in this study. Homogeneity and stability testing were performed by INCQS on the samples sent to the laboratories. Analytical results supplied by the pesticide residues laboratory of the VWA/KvW, Amsterdam, Holland, were used to define the designated value for the thiram concentration in the study samples. RESULTS: Fifty percent of the participating laboratories had satisfactory results. Efforts are needed to improve the precision of the analytical results and to decrease the number of false negative results observed.

O enfoque da metrologia química em análises toxicológicas na atividade turfística: validação de método analítico para determinação de cafeína em matrizes biológicas

This paper proposes an alternate method to detect forbidden doping substances present in biological matrices of horseracing. The method was fully validated for caffeine, identified as the most frequent forbidden substance in the analysis conducted by the Antidoping Laboratory of the Brazilian Jockey Club, which adopts a zero threshold limit according to national and international horseracing practices. The metrological reliability of the method applied to toxicological analysis in biological matrices is discussed. Although the analytical method proposed for detection of a zero threshold level of the doping substance is qualitative, it was validated for the determination of the limiting value (also known as quantification limit value) introducing a criterion that prevents the issuing of incorrect results ("false-positives" and "false-negatives").

Readout electronics for low dark count pixel detectors based on geiger mode avalanche photodiodes fabricated in conventional CMOS technologies for future linear colliders

The high sensitivity and excellent timing accuracy of Geiger mode avalanche photodiodes makes them ideal sensors as pixel detectors for particle tracking in high energy physics experiments to be performed in future linear colliders. Nevertheless, it is well known that these sensors suffer from dark counts and afterpulsing noise, which induce false hits (indistinguishable from event detection) as well as an increase of the necessary area of the readout system. In this work, we present a comparison between APDs fabricated in a high voltage 0.35 µm and a high integration 0.13 µm commercially available CMOS technologies that has been performed to determine which of them best fits the particle collider requirements. In addition, a readout circuit that allows low noise operation is introduced. Experimental characterization of the proposed pixel is also presented in this work.

Lenguaje y Teoría de la mente: una aproximación multidimensional

El propósito de este trabajo es realizar una puesta al día sobre las relaciones entre el desarrollo del lenguaje y el desarrollo de la Teoría de la Mente. Entre las hipótesis propuestas para conceptualizar dichas relaciones, realizamos un examen más exhaustivo de aquellos modelos que apoyan una implicación directa entre lenguaje y Teoría de la Mente. En este contexto, en primer lugar subrayamos la necesidad de ampliar dicha noción para incluir habilidades anteriores y posteriores a la comprensión de la falsa creencia. En segundo lugar, examinamos las diferentes hipótesis acerca de los aspectos del lenguaje más vinculados al desarrollo sociocognitivo, y las principales evidencias empíricas que las sustentan. Finalmente, discutimos un modelo de causalidad recíproca donde los vínculos entre lenguaje y Teoría de la Mente variarán según el momento del desarrollo considerado

Habilidades de cognición social en niños y niñas con el síndrome de Down: resultados de un estudio preliminar

The understanding of false belief is one of the most important milestones in the development of social cognition in children. Many studies have been conducted on this kind of cognition in children with a typical development. Despite being a key point for improving their welfare and quality of life, there are few studies in children with Down's syndrome. The aim of the present work is to carry out an in-depth study of social cognition in children with Down's syndrome. For this purpose, we used 6 tasks, with 3 levels of difficulty, in a group of 9 children aged between 4 and 14 years. Six of these children had a genetic diagnosis of Down's syndrome. The results of our research corroborate previous studies suggesting difficulties in the development of social cognition in children with Down's syndrome, and more specifically in tasks involving false beliefs

La escala de análisis: un tema central en didáctica de la geografía = The scale of analysis a central didactic theme in Geography

Geographical scale is not merely a technical question. The learning of geographical scale goes beyond geometricunderstanding; it implies the etymological comprehension of the concept, the recognition of the importance of scale in theelaboration of the geographical discourse. It implies placing oneself in the centre of the teaching and learning of Geographyand asking oneself, what scale? Why this scale? What progression of scales? The answer to these questions puts in doubtthe scientific discourse that is presently taught in schools especially on the scale of analysis, the sequencing of studiedspaces and the false dichotomy local and global

Estudo do teste de Scott via técnicas espectroscópicas: um método alternativo para diferenciar cloridrato de cocaína e seus adulterantes

Cocaine is usually seized mixed with a wide variety of adulterants such as benzocaine, lidocaine, caffeine, and procaine. The forensic identification of cocaine in these street drug mixtures is normally performed using colorimetric testing kits, but these tests may suffer from interferences, producing false-positive results. Here, we describe the use of analytical techniques including attenuated total reflection Fourier transform infrared (ATR-FTIR) and ultraviolet-visible (UV-VIS) spectroscopies to distinguish between cocaine and other adulterants (lidocaine, promethazine, powdered milk and yeast) that yield positive results on the Scott test using the thiocyanate cobalt reagent. A further 13 substances were also analyzed using the Scott test.

Arvonlisäveropetokset ja niiden ehkäiseminen

Tämän tutkielman tavoitteena on tutkia suomalaisen liiketoimintaa harjoittavan yrityksen mahdolliset väärinkäyttötilanteet liittyen arvonlisäverovelvollisuuteen sekä mahdolliset ratkaisut, joilla arvonlisäveroväärinkäytöksiä voidaan hallita. Mahdollisia vaarinkatostapoja ovat muun muassa: vääränsisältöiset ilmoitukset, perusteettomat ostotositteet, perusteettoman arvonlisäveropalautuksen hakeminen, toimiminen verovalvonnan ulkopuolella, veron maksamatta jättäminen, verokantojen väärentäminen, ketjupetos, karusellipetos, marginaaliverokeinottelu ja toisen yhtiön alv-tunnisteen käyttö. Torjunta- tai hallintakeinoja ovat muun muassa: käännetty verovelvollisuus, verotili, kansainvälinen tietojenvaihto, yhteisvastuu, verovalvonnan tehostaminen ja ajantasaistaminen, rekisteröitymisien tarkistaminen ja lopullinen verojärjestelmä.

Study of ligand-based virtual screening tools in computer-aided drug design

Virtual screening is a central technique in drug discovery today. Millions of molecules can be tested in silico with the aim to only select the most promising and test them experimentally. The topic of this thesis is ligand-based virtual screening tools which take existing active molecules as starting point for finding new drug candidates. One goal of this thesis was to build a model that gives the probability that two molecules are biologically similar as function of one or more chemical similarity scores. Another important goal was to evaluate how well different ligand-based virtual screening tools are able to distinguish active molecules from inactives. One more criterion set for the virtual screening tools was their applicability in scaffold-hopping, i.e. finding new active chemotypes. In the first part of the work, a link was defined between the abstract chemical similarity score given by a screening tool and the probability that the two molecules are biologically similar. These results help to decide objectively which virtual screening hits to test experimentally. The work also resulted in a new type of data fusion method when using two or more tools. In the second part, five ligand-based virtual screening tools were evaluated and their performance was found to be generally poor. Three reasons for this were proposed: false negatives in the benchmark sets, active molecules that do not share the binding mode, and activity cliffs. In the third part of the study, a novel visualization and quantification method is presented for evaluation of the scaffold-hopping ability of virtual screening tools.

Print-capture PCR for detection of tomato begomoviruses from plants and whiteflies

Print-capture (PC) Polymerase chain reaction (PCR) was evaluated as a novel detection method of plant viruses. Tomato (Lycopersicon esculentum) plants infected with begomovirus (fam. Geminiviridae, gen. Begomovirus) and viruliferous whiteflies were used to study the efficiency of the method. Print-capturing steps were carried out using non-charged nylon membrane or filter paper as the solid support for DNA printings. Amplified DNA fragments of expected size were consistently obtained by PCR from infected plants grown in a greenhouse, after direct application of printed materials to the PCR mix. However, virus detection from a single whitefly and from field-grown tomato samples required a high temperature treatment of printed material prior to PCR amplification. Comparison of nylon membrane and filter paper as the solid support revealed the higher efficiency of the nylon membrane. The application of print-capture PCR reduces the chances of false-positive amplification by reducing manipulation steps during preparation of the target DNA. This method maintains all the advantages of PCR diagnosis, such as the high sensitivity and no requirement of radioactive reagents.