978 resultados para Physical and chemical characteristics


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Over the past two decades, soil ecotoxicologists have made strides in utilizing the basic concepts and advancements in soil zoology and ecology. They have applied the existing tools, and developed new ones to investigate how chemical contamination can affect soil ecosystems, including the degradation or destruction of soil quality and habitats or the diminishment of belowground biodiversity. Soil ecotoxicologists are applying a suite of standard protocols, originally developed as laboratory tests with single chemicals (e.g., pesticides), and further enhancing both the approaches and protocols for the assessment of contaminated lands. However, ecological relevance of some approaches remains unresolved. The authors discuss the main challenges for a coherent ecotoxicological assessment of soil ecosystems amid contaminated lands, and provide recommendations on how to integrate the effects of physical and chemical soil properties, the variations in the diversity of soil invertebrates, and the interactions among organisms of various trophic levels. The review examines new international approaches and test methods using examples from three continents (in particular research conducted in Brazil), and provides recommendations for improving ecological relevance of ecotoxicological investigations of contaminated lands.

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The objective of the present work was to characterize banana accessions from the Germplasm Bank at Embrapa Mandioca e Fruticultura Tropical (Brazil), using agronomical, physical and physicochemical characteristics of fruit and simple sequence repeats (SSR) markers. Twenty-six accessions were analyzed, in which high genetic variability was found, especially for the agronomical characters number of fruit and weight of bunch. Accessions with high contents of carotenoids (diploid 'Jaran'), polyphenols (triploid 'Caipira' and tetraploid 'Teparod') and vitamin C (diploid 'Tuugia' and an unknown triploid AAA) in the fruit were identified. Thirteen microsatellite primers revealed an average of 7.23 alleles, which showed high variability. A dendrogram was prepared using the Gower algorithm for the distance matrices obtained from the agronomical, physical and physicolchemical analysis of fruit and SSR markers. Adopting the average genetic divergence as the cut-off point, three clusters were found: G1, formed by the diploids 'Jaran', 028003-01 and M-48; G2, by the diploids 'Malbut' and 'Ido 110'; and G3, by 21 tri-and tetraploid accessions, including one diploid, 'Tuugia'. The triploids with the B genome 'Thap Maeo', 'Walha', 'Pacha Nadan' and 'Champa Madras' were grouped in G2. Results from this work can be used for breeding hybrids with good agronomical traits and fruit quality.

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The major objective of this research project is to investigate the chemistry and morphology of Portland cement concrete pavements in Iowa. The integrity of the various pavements is being ascertained based on the presence or absence of microcracks, the presence or absence of sulfate minerals, and the presence or absence of alkali-silica gel(s). Work is also being done on quantifying the air content of the concrete using image analysis techniques since this often appears to be directly related to the sulfate minerals that are commonly observed in the pavement cores.

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Raman spectroscopy combined with chemometrics has recently become a widespread technique for the analysis of pharmaceutical solid forms. The application presented in this paper is the investigation of counterfeit medicines. This increasingly serious issue involves networks that are an integral part of industrialized organized crime. Efficient analytical tools are consequently required to fight against it. Quick and reliable authentication means are needed to allow the deployment of measures from the company and the authorities. For this purpose a method in two steps has been implemented here. The first step enables the identification of pharmaceutical tablets and capsules and the detection of their counterfeits. A nonlinear classification method, the Support Vector Machines (SVM), is computed together with a correlation with the database and the detection of Active Pharmaceutical Ingredient (API) peaks in the suspect product. If a counterfeit is detected, the second step allows its chemical profiling among former counterfeits in a forensic intelligence perspective. For this second step a classification based on Principal Component Analysis (PCA) and correlation distance measurements is applied to the Raman spectra of the counterfeits.

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This bulletin is a compilation of the reports on completed research done for the Iowa State Highway Research Board Project HR-1, "The Loess and Glacial Till Materials of Iowa; an Investigation of Their Physical and Chemical Properties and Techniques for Processing Them to Increase Their All-Weather Stability for Road Construction.” The research, started in 1950, was done by the Iowa Engineering Experiment Station under its project 283-S. The project was supported by funds from the Iowa State Highway Commission.

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The Internet is becoming more and more popular among drug users. The use of websites and forums to obtain illicit drugs and relevant information about the means of consumption is a growing phenomenon mainly for new synthetic drugs. Gamma Butyrolactone (GBL), a chemical precursor of Gamma Hydroxy Butyric acid (GHB), is used as a "club drug" and also in drug facilitated sexual assaults. Its market takes place mainly on the Internet through online websites but the structure of the market remains unknown. This research aims to combine digital, physical and chemical information to help understand the distribution routes and the structure of the GBL market. Based on an Internet monitoring process, thirty-nine websites selling GBL, mainly in the Netherlands, were detected between January 2010 and December 2011. Seventeen websites were categorized into six groups based on digital traces (e.g. IP addresses and contact information). In parallel, twenty-five bulk GBL specimens were purchased from sixteen websites for packaging comparisons and carbon isotopic measurements. Packaging information showed a high correlation with digital data confirming the links previously established whereas chemical information revealed undetected links and provided complementary information. Indeed, while digital and packaging data give relevant information about the retailers, the supply routes and the distribution close to the consumer, the carbon isotopic data provides upstream information about the production level and in particular the synthesis pathways and the chemical precursors. A three-level structured market has been thereby identified with a production level mainly located in China and in Germany, an online distribution level mainly hosted in the Netherlands and the customers who order on the Internet.

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The objective of this work was to evaluate the microbiological and chemical attributes of a soil with a seven‑year history of urea and swine manure application. In the period from October 2008 to October 2009, soil samples were collected in the 0-10 cm layer and were subjected to the treatments: control, without application of urea or manure; and with the application of urea, pig slurry, and deep pig litter in two doses, in order to supply one or two times the recommended N doses for the maize (Zea mays)/black oat (Avena strigosa) crop succession. The carbon of the microbial biomass (MB‑C) and the basal respiration (C‑CO2) were analyzed, and the metabolic (qCO2) and microbial quotient (qmic) were calculated with the obtained data. Organic matter, pH in water, available P and K, and exchangeable Ca and Mg were also determined. The application of twice the dose of deep pig litter increases the MB‑C and C‑CO2 values. The qmic and qCO2 are little affected by the application of swine manure. The application of twice the dose of deep pig litter increases the values of pH in water and the contents of available P and of exchangeable Ca and Mg in the soil.

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Physical and psychological stress cause different patterns of changes in the fluorescence intensity of nigral and tuberoinfundibular DA neurons which point to changes in neuronal activity. In order to investigate possible interactions between alpha-MSH (alpha-melanotropin) and DA systems in stress, systemic and intraventricular injections of antiserum against alpha-MSH were made. The functional state of DA neurons was assessed by histochemical microfluorimetry and hormone levels were measured by radioimmunossay. Antiserum against alpha-MSH was found to affect the functional state of DA neurons, but only thorugh the intravenous route. Under physical stress i.v. injection of antiserum against alpha-MSH was accompanied by elevated levels of activity of the DA neurons of the substantia nigra. An intraventricular injection of the same antiserum was ineffective. In psychological stress, an effect was again seen only after intravenous injection of antiserum against alpha-MSH. In this situation, the activity in DA cell groups of the substantia nigra, ventral tegmental area and tubero-infundibular system was increased after antiserum injection. Possible influences from manipulations were checked; certain effects which depended upon experimental situation were noted. Our data suggest a modulatory influence of circulating alpha-MSH on the functional state of central DA systems.

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INTRODUCTION: To assess the impact of duration of untreated psychosis (DUP) on baseline and 18-month follow-up characteristics controlling for relevant confounders in an epidemiological first-episode psychosis (FEP) cohort. METHOD: The Early Psychosis Prevention and Intervention Centre (EPPIC) in Australia admitted 786 FEP patients from January 1998 to December 2000. Data were collected from medical files using a standardized questionnaire. Data from 636 patients were analyzed. RESULTS: Median DUP was 8.7 weeks. Longer DUP was associated with worse premorbid functioning (p<0.001), higher rate of schizophrenia-spectrum disorders (p<0.001), and younger age at onset of psychosis (p=0.004). Longer DUP was not associated with baseline variables but with a lower rate of remission of positive symptoms (p<0.001) and employment/occupation (p<0.001), a higher rate of persistent substance use (p=0.015), worse illness severity (p<0.001) and global functioning (p<0.001) at follow-up after controlling for relevant confounders, explaining approximately 5% of variance of remission of positive symptoms (p<0.001) in the total sample and 3% in schizophrenia-spectrum disorders excluding bipolar I disorder (p=0.002). Outcome was significantly worse when DUP exceeded 1-3 months. CONCLUSION: Avoiding pitfalls of non-epidemiological studies, DUP appears to be a modest independent predictor of prognosis in the medium-term. Results support the need for assertive early detection strategies.