963 resultados para Loss Determination in Microsphere Resonators
Resumo:
Recent findings suggest an association between exposure to cleaning products and respiratory dysfunctions including asthma. However, little information is available about quantitative airborne exposures of professional cleaners to volatile organic compounds deriving from cleaning products. During the first phases of the study, a systematic review of cleaning products was performed. Safety data sheets were reviewed to assess the most frequently added volatile organic compounds. It was found that professional cleaning products are complex mixtures of different components (compounds in cleaning products: 3.5 ± 2.8), and more than 130 chemical substances listed in the safety data sheets were identified in 105 products. The main groups of chemicals were fragrances, glycol ethers, surfactants, solvents; and to a lesser extent phosphates, salts, detergents, pH-stabilizers, acids, and bases. Up to 75% of products contained irritant (Xi), 64% harmful (Xn) and 28% corrosive (C) labeled substances. Hazards for eyes (59%), skin (50%) and by ingestion (60%) were the most reported. Monoethanolamine, a strong irritant and known to be involved in sensitizing mechanisms as well as allergic reactions, is frequently added to cleaning products. Monoethanolamine determination in air has traditionally been difficult and air sampling and analysis methods available were little adapted for personal occupational air concentration assessments. A convenient method was developed with air sampling on impregnated glass fiber filters followed by one step desorption, gas chromatography and nitrogen phosphorous selective detection. An exposure assessment was conducted in the cleaning sector, to determine airborne concentrations of monoethanolamine, glycol ethers, and benzyl alcohol during different cleaning tasks performed by professional cleaning workers in different companies, and to determine background air concentrations of formaldehyde, a known indoor air contaminant. The occupational exposure study was carried out in 12 cleaning companies, and personal air samples were collected for monoethanolamine (n=68), glycol ethers (n=79), benzyl alcohol (n=15) and formaldehyde (n=45). All but ethylene glycol mono-n-butyl ether air concentrations measured were far below (<1/10) of the Swiss eight hours occupational exposure limits, except for butoxypropanol and benzyl alcohol, where no occupational exposure limits were available. Although only detected once, ethylene glycol mono-n-butyl ether air concentrations (n=4) were high (49.5 mg/m3 to 58.7 mg/m3), hovering at the Swiss occupational exposure limit (49 mg/m3). Background air concentrations showed no presence of monoethanolamine, while the glycol ethers were often present, and formaldehyde was universally detected. Exposures were influenced by the amount of monoethanolamine in the cleaning product, cross ventilation and spraying. The collected data was used to test an already existing exposure modeling tool during the last phases of the study. The exposure estimation of the so called Bayesian tool converged with the measured range of exposure the more air concentrations of measured exposure were added. This was best described by an inverse 2nd order equation. The results suggest that the Bayesian tool is not adapted to predict low exposures. The Bayesian tool should be tested also with other datasets describing higher exposures. Low exposures to different chemical sensitizers and irritants should be further investigated to better understand the development of respiratory disorders in cleaning workers. Prevention measures should especially focus on incorrect use of cleaning products, to avoid high air concentrations at the exposure limits. - De récentes études montrent l'existence d'un lien entre l'exposition aux produits de nettoyages et les maladies respiratoires telles que l'asthme. En revanche, encore peu d'informations sont disponibles concernant la quantité d'exposition des professionnels du secteur du nettoyage aux composants organiques volatiles provenant des produits qu'ils utilisent. Pendant la première phase de cette étude, un recueil systématique des produits professionnels utilisés dans le secteur du nettoyage a été effectué. Les fiches de données de sécurité de ces produits ont ensuite été analysées, afin de répertorier les composés organiques volatiles les plus souvent utilisés. Il a été mis en évidence que les produits de nettoyage professionnels sont des mélanges complexes de composants chimiques (composants chimiques dans les produits de nettoyage : 3.5 ± 2.8). Ainsi, plus de 130 substances listées dans les fiches de données de sécurité ont été retrouvées dans les 105 produits répertoriés. Les principales classes de substances chimiques identifiées étaient les parfums, les éthers de glycol, les agents de surface et les solvants; dans une moindre mesure, les phosphates, les sels, les détergents, les régulateurs de pH, les acides et les bases ont été identifiés. Plus de 75% des produits répertoriés contenaient des substances décrites comme irritantes (Xi), 64% nuisibles (Xn) et 28% corrosives (C). Les risques pour les yeux (59%), la peau (50%) et par ingestion (60%) était les plus mentionnés. La monoéthanolamine, un fort irritant connu pour être impliqué dans les mécanismes de sensibilisation tels que les réactions allergiques, est fréquemment ajouté aux produits de nettoyage. L'analyse de la monoéthanolamine dans l'air a été habituellement difficile et les échantillons d'air ainsi que les méthodes d'analyse déjà disponibles étaient peu adaptées à l'évaluation de la concentration individuelle d'air aux postes de travail. Une nouvelle méthode plus efficace a donc été développée en captant les échantillons d'air sur des filtres de fibre de verre imprégnés, suivi par une étape de désorption, puis une Chromatographie des gaz et enfin une détection sélective des composants d'azote. Une évaluation de l'exposition des professionnels a été réalisée dans le secteur du nettoyage afin de déterminer la concentration atmosphérique en monoéthanolamine, en éthers de glycol et en alcool benzylique au cours des différentes tâches de nettoyage effectuées par les professionnels du nettoyage dans différentes entreprises, ainsi que pour déterminer les concentrations atmosphériques de fond en formaldéhyde, un polluant de l'air intérieur bien connu. L'étude de l'exposition professionnelle a été effectuée dans 12 compagnies de nettoyage et les échantillons d'air individuels ont été collectés pour l'éthanolamine (n=68), les éthers de glycol (n=79), l'alcool benzylique (n=15) et le formaldéhyde (n=45). Toutes les substances mesurées dans l'air, excepté le 2-butoxyéthanol, étaient en-dessous (<1/10) de la valeur moyenne d'exposition aux postes de travail en Suisse (8 heures), excepté pour le butoxypropanol et l'alcool benzylique, pour lesquels aucune valeur limite d'exposition n'était disponible. Bien que détecté qu'une seule fois, les concentrations d'air de 2-butoxyéthanol (n=4) étaient élevées (49,5 mg/m3 à 58,7 mg/m3), se situant au-dessus de la frontière des valeurs limites d'exposition aux postes de travail en Suisse (49 mg/m3). Les concentrations d'air de fond n'ont montré aucune présence de monoéthanolamine, alors que les éthers de glycol étaient souvent présents et les formaldéhydes quasiment toujours détectés. L'exposition des professionnels a été influencée par la quantité de monoéthanolamine présente dans les produits de nettoyage utilisés, par la ventilation extérieure et par l'emploie de sprays. Durant la dernière phase de l'étude, les informations collectées ont été utilisées pour tester un outil de modélisation de l'exposition déjà existant, l'outil de Bayesian. L'estimation de l'exposition de cet outil convergeait avec l'exposition mesurée. Cela a été le mieux décrit par une équation du second degré inversée. Les résultats suggèrent que l'outil de Bayesian n'est pas adapté pour mettre en évidence les taux d'expositions faibles. Cet outil devrait également être testé avec d'autres ensembles de données décrivant des taux d'expositions plus élevés. L'exposition répétée à des substances chimiques ayant des propriétés irritatives et sensibilisantes devrait être investiguée d'avantage, afin de mieux comprendre l'apparition de maladies respiratoires chez les professionnels du nettoyage. Des mesures de prévention devraient tout particulièrement être orientées sur l'utilisation correcte des produits de nettoyage, afin d'éviter les concentrations d'air élevées se situant à la valeur limite d'exposition acceptée.
Resumo:
Soil erosion is one of the chief causes of agricultural land degradation. Practices of conservation agriculture, such as no-tillage and cover crops, are the key strategies of soil erosion control. In a long-term experiment on a Typic Paleudalf, we evaluated the temporal changes of soil loss and water runoff rates promoted by the transition from conventional to no-tillage systems in the treatments: bare soil (BS); grassland (GL); winter fallow (WF); intercrop maize and velvet bean (M+VB); intercrop maize and jack bean (M+JB); forage radish as winter cover crop (FR); and winter cover crop consortium ryegrass - common vetch (RG+CV). Intensive soil tillage induced higher soil losses and water runoff rates; these effects persisted for up to three years after the adoption of no-tillage. The planting of cover crops resulted in a faster decrease of soil and water loss rates in the first years after conversion from conventional to no-tillage than to winter fallow. The association of no-tillage with cover crops promoted progressive soil stabilization; after three years, soil losses were similar and water runoff was lower than from grassland soil. In the treatments of cropping systems with cover crops, soil losses were reduced by 99.7 and 66.7 %, compared to bare soil and winter fallow, while the water losses were reduced by 96.8 and 71.8 % in relation to the same treatments, respectively.
Resumo:
Recognition and identification processes for deceased persons. Determining the identity of deceased persons is a routine task performed essentially by police departments and forensic experts. This thesis highlights the processes necessary for the proper and transparent determination of the civil identities of deceased persons. The identity of a person is defined as the establishment of a link between that person ("the source") and information pertaining to the same individual ("identifiers"). Various identity forms could emerge, depending on the nature of the identifiers. There are two distinct types of identity, namely civil identity and biological identity. The paper examines four processes: identification by witnesses (the recognition process) and comparisons of fingerprints, dental data and DNA profiles (the identification processes). During the recognition process, the memory function is examined and helps to clarify circumstances that may give rise to errors. To make the process more rigorous, a body presentation procedure is proposed to investigators. Before examining the other processes, three general concepts specific to forensic science are considered with regard to the identification of a deceased person, namely, matter divisibility (Inman and Rudin), transfer (Locard) and uniqueness (Kirk). These concepts can be applied to the task at hand, although some require a slightly broader scope of application. A cross comparison of common forensic fields and the identification of deceased persons reveals certain differences, including 1 - reverse positioning of the source (i.e. the source is not sought from traces, but rather the identifiers are obtained from the source); 2 - the need for civil identity determination in addition to the individualisation stage; and 3 - a more restricted population (closed set), rather than an open one. For fingerprints, dental and DNA data, intravariability and intervariability are examined, as well as changes in these post mortem (PM) identifiers. Ante-mortem identifiers (AM) are located and AM-PM comparisons made. For DNA, it has been shown that direct identifiers (taken from a person whose civil identity has been alleged) tend to lead to determining civil identity whereas indirect identifiers (obtained from a close relative) direct towards a determination of biological identity. For each process, a Bayesian model is presented which includes sources of uncertainty deemed to be relevant. The results of the different processes combine to structure and summarise an overall outcome and a methodology. The modelling of dental data presents a specific difficulty with respect to intravariability, which in itself is not quantifiable. The concept of "validity" is, therefore, suggested as a possible solution to the problem. Validity uses various parameters that have an acknowledged impact on teeth intravariability. In cases where identifying deceased persons proves to be extremely difficult due to the limited discrimination of certain procedures, the use of a Bayesian approach is of great value in bringing a transparent and synthetic value. RESUME : Titre: Processus de reconnaissance et d'identification de personnes décédées. L'individualisation de personnes décédées est une tâche courante partagée principalement par des services de police, des odontologues et des laboratoires de génétique. L'objectif de cette recherche est de présenter des processus pour déterminer valablement, avec une incertitude maîtrisée, les identités civiles de personnes décédées. La notion d'identité est examinée en premier lieu. L'identité d'une personne est définie comme l'établissement d'un lien entre cette personne et des informations la concernant. Les informations en question sont désignées par le terme d'identifiants. Deux formes distinctes d'identité sont retenues: l'identité civile et l'identité biologique. Quatre processus principaux sont examinés: celui du témoignage et ceux impliquant les comparaisons d'empreintes digitales, de données dentaires et de profils d'ADN. Concernant le processus de reconnaissance, le mode de fonctionnement de la mémoire est examiné, démarche qui permet de désigner les paramètres pouvant conduire à des erreurs. Dans le but d'apporter un cadre rigoureux à ce processus, une procédure de présentation d'un corps est proposée à l'intention des enquêteurs. Avant d'entreprendre l'examen des autres processus, les concepts généraux propres aux domaines forensiques sont examinés sous l'angle particulier de l'identification de personnes décédées: la divisibilité de la matière (Inman et Rudin), le transfert (Locard) et l'unicité (Kirk). Il est constaté que ces concepts peuvent être appliqués, certains nécessitant toutefois un léger élargissement de leurs principes. Une comparaison croisée entre les domaines forensiques habituels et l'identification de personnes décédées montre des différences telles qu'un positionnement inversé de la source (la source n'est plus à rechercher en partant de traces, mais ce sont des identifiants qui sont recherchés en partant de la source), la nécessité de devoir déterminer une identité civile en plus de procéder à une individualisation ou encore une population d'intérêt limitée plutôt qu'ouverte. Pour les empreintes digitales, les dents et l'ADN, l'intra puis l'inter-variabilité sont examinées, de même que leurs modifications post-mortem (PM), la localisation des identifiants ante-mortem (AM) et les comparaisons AM-PM. Pour l'ADN, il est démontré que les identifiants directs (provenant de la personne dont l'identité civile est supposée) tendent à déterminer une identité civile alors que les identifiants indirects (provenant d'un proche parent) tendent à déterminer une identité biologique. Puis une synthèse des résultats provenant des différents processus est réalisée grâce à des modélisations bayesiennes. Pour chaque processus, une modélisation est présentée, modélisation intégrant les paramètres reconnus comme pertinents. À ce stade, une difficulté apparaît: celle de quantifier l'intra-variabilité dentaire pour laquelle il n'existe pas de règle précise. La solution préconisée est celle d'intégrer un concept de validité qui intègre divers paramètres ayant un impact connu sur l'intra-variabilité. La possibilité de formuler une valeur de synthèse par l'approche bayesienne s'avère d'une aide précieuse dans des cas très difficiles pour lesquels chacun des processus est limité en termes de potentiel discriminant.
Resumo:
The purpose of this study was to evaluate the postmortem distributions of procalcitonin (PCT), C-reactive protein (CRP), soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) and soluble interleukin-2 receptor (sIL-2R) levels in postmortem serum from femoral blood, pericardial fluid and pleural fluid in a series of sepsis-related fatalities (12 subjects) and control cases (20 subjects) that underwent medico-legal investigations. Our aim was to assess the diagnostic potential of the results obtained from pericardial and pleural fluid analysis in identifying sepsis-related deaths. All sepsis-related cases had a documented, clinical diagnosis that was established in vivo during hospitalization. Pneumonia was the main infectious focus identified during autopsy and histology. Pseudomonas aeruginosa, Klebsiella pnemoniae and Escherichia coli were the most commonly identified bacteria in blood and lung tissue cultures. The preliminary results corroborate the usefulness of PCT, CRP, sTREM-1 and sIL-2R determination in postmortem serum for the identification of sepsis-related deaths. Moreover, the data suggest that, as far as PCT, CRP, sTREM-1 and sIL-2R measurements are concerned, pericardial and pleural fluids can be considered suitable alternatives to postmortem serum should femoral blood prove unavailable at autopsy.
Resumo:
The growth of five variables of the tibia (diaphyseal length, diaphyseal length plus distal epiphysis, condylo-malleolar length, sagittal diameter of the proximal epiphysis, maximum breadth of the distal epiphysis) were analysed using polynomial regression in order to evaluate their significance and capacity for age and sex determination during and after growth. Data were collected from 181 (90♂ and 91♀) individuals ranging from birth to 25 years of age and belonging to three documented collections from Western Europe. Results indicate that all five variables exhibit linear behaviour during growth, which can be expressed by a first-degree polynomial function. Sexual significant differences were observed from age 15 onward in the two epiphysis measurements and condylo-malleolar length, suggesting that these three variables could be useful for sex determination in individuals older than 15 years. Strong correlation coefficients were identified between the five tibial variables and age. These results indicate that any of the studied tibial measurements is likely to serve as a useful source for estimating sub-adult age in both archaeological and forensic samples.
Resumo:
Tässä työssä kuvataan erilaisia malleja palveluiden hinnoitteluun. Työn tavoitteena on saada kokonaiskuva erilaisista palveluiden hinnoittelumalleista. Lähtökohtana ovat palveluiden, hinnan, hinnoittelun ja kustannusten määritelmät. Malleista kuvataan hinnoittelun peruste, yleisiä käyttökohteita sekä vahvuuksia ja heikkouksia. Eri mallit on jaettu kahteen osaan. Yrityskohtaiset mallit kuvaavat laajasti hinnoitteluprosessia. Yksityiskohtaisemmat palvelukohtaiset mallit on jaettu resurssi-, tuotos-, käyttöoikeus- ja käyttöperusteisiin, sekä hyöty- ja arvoperusteisiin menetelmiin. Täydellistä kaikille palveluille sopivaa hinnoittelumenetelmää ei ole. Jokaisessa mallissa on heikkouksia ja vahvuuksia. Eri menetelmät soveltuvat erilaisiin tilanteisiin ja niitä käytetään yrityksissä usein rinnakkain niin sanottuina hybridimalleina. Lisäksi palveluiden hinnoitteluun liittyy yllättävän paljon intuitiota ja kokemuksellista tietoa.
Resumo:
Regeneration of lost tissues depends on the precise interpretation of molecular signals that control and coordinate the onset of proliferation, cellular differentiation and cell death. However, the nature of those molecular signals and the mechanisms that integrate the cellular responses remain largely unknown. The planarian flatworm is a unique model in which regeneration and tissue renewal can be comprehensively studied in vivo. The presence of a population of adult pluripotent stem cells combined with the ability to decode signaling after wounding enable planarians to regenerate a complete, correctly proportioned animal within a few days after any kind of amputation, and to adapt their size to nutritional changes without compromising functionality. Here, we demonstrate that the stress-activated c-jun-NH2-kinase (JNK) links wound-induced apoptosis to the stem cell response during planarian regeneration. We show that JNK modulates the expression of wound-related genes, triggers apoptosis and attenuates the onset of mitosis in stem cells specifically after tissue loss. Furthermore, in pre-existing body regions, JNK activity is required to establish a positive balance between cell death and stem cell proliferation to enable tissue renewal, remodeling and the maintenance of proportionality. During homeostatic degrowth, JNK RNAi blocks apoptosis, resulting in impaired organ remodeling and rescaling. Our findings indicate that JNK-dependent apoptotic cell death is crucial to coordinate tissue renewal and remodeling required to regenerate and to maintain a correctly proportioned animal. Hence, JNK might act as a hub, translating wound signals into apoptotic cell death, controlled stem cell proliferation and differentiation, all of which are required to coordinate regeneration and tissue renewal.
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The simultaneous determination of cobalt and nickel is a classical analytical problem. A great number of reagents associated with several techniques of analysis have been applied to achieve this determination. In this review 117 references, which appeared between 1996-1980, are described and classified according to the technique applied.
Resumo:
Selectivity studies for the determination of Cr(VI) using the catalytic oxidation of the o-dianisidine by hydrogen peroxide showed two distincts situations. In the first, when interferents were studied by a univariate procedure, Cr(III) and Cu(II) cause serious interferences even at the 2:1 proportion, relative to Cr(VI), while Fe(III) interfered at the 15:1 ratio and EDTA at the 10:1 ratio. On the other hand, when a multivariate investigation was performed, Cr(III) did not present any significant principal effects and its significant interaction effects were negative, in contrast to EDTA, that presented positive interaction effects although, like Cr(III), did not show significant interaction effects. In view of the interferent's action it become necessary to separate Cr(VI) by extraction with methylisobutylketone in a chloridric acid medium before its determination in vegetals and in wastewater from a cellulose industry samples. Using this procedure, the method precision is ±0,5% at the 10 ng/mL Cr(VI) concentration level. The detection and quantification limits, calculated by means of absorbance measurements of ten replicates of blank reagents were 1,1 and 3,2 ng/mL, respectively. The results obtained with real samples showed a relative standard deviation between 1,2% and 3,0% relative to their reference values.
Resumo:
A fast and direct method for the determination of Cr in milk and cane sugar suspensions using graphite furnace atomic absorption spectrometry with Zeeman-effect background correction is described. No sample pre-treatment was necessary, minimizing the risk of contamination. The concentration of chromium in cane sugar was evaluated using Cr reference solutions prepared in 1% v/v HNO3 solution. The milk samples were introduced into the furnace with a mixture of amines for avoiding the autosampler blockage and foaming of milk. Chromium determination in milk was based on the standard additions method (SAM). The limit of detection and characteristic mass for cane sugar sample (30 muL) were 0,13 ng/ml and 4,3 pg, and for milk sample (10 muL) were 0,23 ng/ml and 7,8 pg, respectively. The graphite tube lifetime was 300 firings for sugar-cane sample and 100 firings for milk sample. The heating program was implemented in 68 s.
Resumo:
Selenium is both essential and toxic to man and animals, depending on the concentration and the ingested form. Most fruits and vegetables are poor sources of selenium, but coconut can be a good selenium source. Samples were suspended (1 + 4 v/v) in a mixture of tertiary amines soluble in water (10% v/v CFA-C). This simple sample treatment avoided contamination and decreased the analysis time. The standard additions method was adopted for quantification. The action of the autosampler was improved by the presence of the amines mixture in the suspension. A Varian model AA-800 atomic absorption spectrometer equipped with a graphite furnace and a GTA 100 autosampler was used for selenium determination in coconut water and coconut milk. Background correction was performed by means of the Zeeman effect. Pyrolytically coated graphite tubes were employed. Using Pd as chemical modifier, the pyrolysis and the atomization temperatures were set at 1400 and 2200ºC, respectively. For six samples, the selenium concentration in coconut water varied from 6.5 to 21.0 mug L-1 and in coconut milk from 24.2 to 25.1 mug L-1. The accuracy of the proposed method was evaluated by an addition-recovery experiment and all recovered values are in the 99.5-102.3% range. The main advantage of the proposed method is that it can be directly applied without sample decomposition.
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Polycyclic aromatic hydrocabons (PAHs) and their nitroderivatives (NPAHs) are ubiquitous in the environment and they are produced in several industrial and combustion processes. Some of these compounds are potent carcinogens/mutagens and their determination in biological samples is an important step for exposure control. A review of the analytical methodologies used for the determination of PAHs and their metabolites in biological samples is presented.
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This paper presents an automatic procedure employing a reagent in the form of a slurry in a flow-injection system. The feasibility of the proposal is demonstrated by sulphate determination in water using the Barium Chloranilate method, which is based on the precipitation of barium sulphate. The release of a stoichiometric amount of highly colored chloranilic ions is monitored at 528 nm. The reaction is carried out in alcoholic medium in order to reduce the solubility of the reagent. A considerable improvement in the sensitivity is attained by adding ferric ions to the released chloranilic ions. An on-line filtration step to separate the excess reagent from the released chloranilic ions was necessary. In addition, a column containing a cation exchange resin was included in the manifold to remove potentially interfering ions. The proposed procedure is suitable for 30 determinations per hour and the relative standard deviation is less than 2%. The analytical curve is linear between 0.0 and 40 mg L-1 and the determination limit is about 2.0 mg L-1SO4(2-). Accuracy was confirmed by running several samples already analysed by a standard turbidimetric procedure.
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The aim of this work was to compare the performances of the L'vov and integrated platforms in order to overcome the interferences found on lead determination in zidovudine by ET AAS. Pyrolysis and atomization temperatures found with integrated platform were 700 and 1400°C, respectively. The characteristic masses were 12.7 ± 1.2 pg with integrated platform and 11.1 ± 1.3 pg with grooved platform. The ratio between the slopes of zidovudine and aqueous curves shows a decrease in the interferences when the L'vov platform is used (bAZT/b aq = 0.97 ± 0.10) and the detection limit found was 0.03 µg.g-1. That ratio was 0.85 ± 0.07 with the integrated platform.