962 resultados para Multicomponent mixtures


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In this work, zinc indium tin oxide layers with different compositions are used as the active layer of thin film transistors. This multicomponent transparent conductive oxide is gaining great interest due to its reduced content of the scarce indium element. Experimental data indicate that the incorporation of zinc promotes the creation of oxygen vacancies. In thin-film transistors this effect leads to a higher threshold voltage values. The field-effect mobility is also strongly degraded, probably due to coulomb scattering by ionized defects. A post deposition annealing in air reduces the density of oxygen vacancies and improves the fieldeffect mobility by orders of magnitude. Finally, the electrical characteristics of the fabricated thin-film transistors have been analyzed to estimate the density of states in the gap of the active layers. These measurements reveal a clear peak located at 0.3 eV from the conduction band edge that could be attributed to oxygen vacancies.

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At present, there is little fundamental guidance available to assist contractors in choosing when to schedule saw cuts on joints. To conduct pavement finishing and sawing activities effectively, however, contractors need to know when a concrete mixture is going to reach initial set, or when the sawing window will open. Previous research investigated the use of the ultrasonic pulse velocity (UPV) method to predict the saw-cutting window for early entry sawing. The results indicated that the method has the potential to provide effective guidance to contractors as to when to conduct early entry sawing. The aim of this project was to conduct similar work to observe the correlation between initial setting and conventional sawing time. Sixteen construction sites were visited in Minnesota and Missouri over a two-year period. At each site, initial set was determined using a p-wave propagation technique with a commercial device. Calorimetric data were collected using a commercial semi-adiabatic device at a majority of the sites. Concrete samples were collected in front of the paver and tested using both methods with equipment that was set up next to the pavement during paving. The data collected revealed that the UPV method looks promising for early entry and conventional sawing in the field, both early entry and conventional sawing times can be predicted for the range of mixtures tested.

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The aim of the present study is to investigate the effect of low-permeability concrete, made with reduced water‐to‐binder ratios (w/b) and/or supplementary cementitious materials (SCMs), on the need for air entrainment to achieve freezing‐thawing (F‐T) durability. In the present study, concrete mixes were made with different types of cement (Types I and IP), with or without fly ash replacement (15%), with different water‐to‐binder ratios (w/b =0.25, 0.35, 0.45 and 0.55), and with or without air entraining agent (AEA). All concrete mixtures were controlled to have a similar slump by using different dosages of superplasticizer. The rapid chloride permeability and F-T durability of the concrete samples were determined according to ASTM C1202 and ASTM C666A, respectively. The air void structure of the concrete was studied using the Air Void Analyzer, RapidAir, and porosity tests (ASTM C642). In addition, the general concrete properties, such as slump, air content, unit weight, and 28‐day compressive strength, were evaluated. The results indicate that all concrete mixes with proper air entrainment (ASTM C231 air content ≥ 6%) showed good F‐T resistance (durability factor ≥85%). All concrete mixes without AEA showed poor F‐T resistance (durability factor < 40%), except for one mix that had very low permeability and high strength. This was the concrete made with Type IP cement and with a w/b of 0.25, which had a permeability of 520 coulombs and a compressive strength of 12,760 psi (88 MPa). There were clear relationships between the F‐T durability and hardened concrete properties of non–air entrained concrete. However, such relationships did not exist in concrete with AEA. For concrete with AEA, good F‐T durability was associated with an air void spacing factor ≤ 0.28 mm (by AVA) or ≤ 0.22 mm (by RapidAir).

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The natural formation of the bioactive C17-polyacetylenes (−)-(R)-panaxynol and panaxydol was analyzed by 13C-labeling experiments. For this purpose, plants of Panax ginseng were supplied with 13CO2 under field conditions or, alternatively, sterile root cultures of P. ginseng were supplemented with [U-13C6]glucose. The polyynes were isolated from the labeled roots or hairy root cultures, respectively, and analyzed by quantitative NMR spectroscopy. The same mixtures of eight doubly 13C-labeled isotopologues and one single labeled isotopologue were observed in the C17-polyacetylenes obtained from the two experiments. The polyketide-type labeling pattern is in line with the biosynthetic origin of the compounds via decarboxylation of fatty acids, probably of crepenynic acid. The 13C-study now provides experimental evidence for the biosynthesis of panaxynol and related polyacetylenes in P. ginseng under in planta conditions as well as in root cultures. The data also show that 13CO2 experiments under field conditions are useful to elucidate the biosynthetic pathways of metabolites, including those from roots.

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[spa]Objetivo: El objetivo de este estudio es el diseño de un parche bucoadhesivo para la administración transbucal de clorhidrato de doxepina utilizando diferentes polímeros así como la caracterización de dichos sistemas en cuanto al análisis calorimétrico y la capacidad de hinchamiento.Materiales y métodos: Se ha utilizado clorhidrato de doxepina y diferentes polímeros, carboximetilcelulosa sódica, hidroxipropilmetilcelulosa y chitosan. La calorimetría diferencial de barrido (DSC) se ha realizado en un dispositivo Mettler FP 80 equipado con un horno FP 85 y la capacidad de hinchamiento utilizando placas de agar.Resultados: Se obtienen termogramas de los parches y las mezclas físicas donde se observan transiciones endotérmicas entre 30 y 120º C y el pico endotérmico del principio activo en las mezclas físicas binarias. La entalpía de deshidratación es similar en los polímeros de carboximetilcelulosa sódica y chitosan (281 J/g) siendo menor en la película de hidroxipropilmetilcelulosa (251 J/g), al igual que el porcentaje de hidratación donde se demuestra que los parches elaborados con hidroxipropilmetilcelulosa presenta menor tendencia a captar agua (55,91 %) frente al 67,04 % y 67,30 % de la carboximetilcelulosa sódica y chitosan, respectivamente.Conclusión: Los resultados obtenidos muestran que existe compatibilidad entre los componentes de la formulación y los datos de entalpía se correlacionan con los datos obtenidos en el ensayo de hinchamiento.[eng]The aim of this study is to design a bucoadhesive patch for the transbuccal administration of doxepin hydrochloride using different polymers as well as the characterization of these systems for calorimetric analysis and the swelling capacity. Materials and methods: Doxepin hydrochloride was used as well as various polymers; carboxymethylcellulose sodium, hydroxypropylmethyl cellulose and chitosan. Differential scanning calorimetry (DSC) was carried out using a Mettler FP 80 device equipped with a FP 85 oven and the swelling capacity using agar plates. Results: Thermograms obtained patches and physical mixtures where there are endothermic transitions between 30 and 120º C and the endothermic peak of the active principle in binary physical mixtures. Dehydration enthalpy is similar in polymers of carboxymethylcellulose sodium and chitosan (281 J/g), the film having less hydroxypropylmethylcellulose (251 J/g), the percentage of moisture shows that the patches prepared with hydroxypropylmethylcellulose have less tendency to collect water (55.91 %) compared to 67.04 % and 67.30 % with sodium carboxymethylcellulose and chitosan, respectively. Conclusion: The results show that there is compatibility between the components of the formulation and the enthalpy data correlate

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C75 is a synthetic compound described as having antitumoral properties. It produces hypophagia and weight loss in rodents, limiting its use in cancer therapy but identify- ing it as a potential anti-obesity drug. C75 is a fatty acid synthase (FAS) inhibitor and, through its coenzyme A (CoA) derivative, it acts as a carnitine palmitoyltransferase (CPT) 1 inhibitor. Racemic mixtures of C75 have been used in all the previous studies; however, the potential dif- ferent biological activities of C75 enantiomers have not been examined yet. To address this question we synthesized the two C75 enantiomers separately. Our results showed that ( )- C75 inhibits FAS activity in vitro and has a cytotoxic effect on tumor cell lines, without affecting food consumption. (+)-C75 inhibits CPT1 and its administration produces anorexia, suggesting that central inhibition of CPT1 is essential for the anorectic effect of C75. The differential activity of C75 enantiomers may lead to the development of potential new specific drugs for cancer and obesity.

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Several methods and approaches for measuring parameters to determine fecal sources of pollution in water have been developed in recent years. No single microbial or chemical parameter has proved sufficient to determine the source of fecal pollution. Combinations of parameters involving at least one discriminating indicator and one universal fecal indicator offer the most promising solutions for qualitative and quantitative analyses. The universal (nondiscriminating) fecal indicator provides quantitative information regarding the fecal load. The discriminating indicator contributes to the identification of a specific source. The relative values of the parameters derived from both kinds of indicators could provide information regarding the contribution to the total fecal load from each origin. It is also essential that both parameters characteristically persist in the environment for similar periods. Numerical analysis, such as inductive learning methods, could be used to select the most suitable and the lowest number of parameters to develop predictive models. These combinations of parameters provide information on factors affecting the models, such as dilution, specific types of animal source, persistence of microbial tracers, and complex mixtures from different sources. The combined use of the enumeration of somatic coliphages and the enumeration of Bacteroides-phages using different host specific strains (one from humans and another from pigs), both selected using the suggested approach, provides a feasible model for quantitative and qualitative analyses of fecal source identification.

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C75 is a synthetic compound described as having antitumoral properties. It produces hypophagia and weight loss in rodents, limiting its use in cancer therapy but identify- ing it as a potential anti-obesity drug. C75 is a fatty acid synthase (FAS) inhibitor and, through its coenzyme A (CoA) derivative, it acts as a carnitine palmitoyltransferase (CPT) 1 inhibitor. Racemic mixtures of C75 have been used in all the previous studies; however, the potential dif- ferent biological activities of C75 enantiomers have not been examined yet. To address this question we synthesized the two C75 enantiomers separately. Our results showed that ( )- C75 inhibits FAS activity in vitro and has a cytotoxic effect on tumor cell lines, without affecting food consumption. (+)-C75 inhibits CPT1 and its administration produces anorexia, suggesting that central inhibition of CPT1 is essential for the anorectic effect of C75. The differential activity of C75 enantiomers may lead to the development of potential new specific drugs for cancer and obesity.

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This work presents geochemistry and structural geology data concerning the low enthalpy geothermal circuits of the Argentera crystalline Massif in northwestern Italian Alps. I n this area some thermal springs (50-60 degreesC), located in the small Bagni di Vinadio village, discharge mixtures made up of a Na-Cl end-member and a Na-SO4 component. The latter is also discharged by the thermal springs of Terme di Valdieri located some kilometres apart within the same tectonic complex. Both end-members share the same meteoric origin and the same reservoir temperature, which is close to 150 degreesC. Explanations are thus required to understand how they reach the surface and how waters of the same origin and circulating in similar rocks can attain such different compositions. Sodium-sulphate waters discharged at both sites, likely represent the common interaction product of meteoric waters with the widespread granitic-migmatitic rocks of the Argentera Massif, whereas Na-CI waters originate through leaching of mineralised cataclastic rocks, which are rich in phyllosilicatic minerals and fluid inclusions, both acting as Cl- sources. Due to the relatively low inferred geothermal gradient of the region, -25C/km, meteoric waters have to descend to depths of 5.5-6 km to attain temperatures of similar to 150 degreesC. These relevant depths can be reached by descending meteoric waters, due to the recent extensional stress field, which allows the development of geothermal circulations at greater depths than in other sectors of the Alps by favouring a greater fractures aperture. The ascent of the thermal waters rakes place along brittle shear zones. In both sites, the thermal waters emerge at the bottoms of the valleys, close to either the lateral termination of a brittle shear zone at Terme di Valdieri, or a step-over between two en-echelon brittle shear zones at Bagni di Vinadio. These observations attest to a strong control operated on the location of outlet regions by both brittle tectonics and the minima in hydraulic potential inside the fractured massif.

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The objective of this research was to evaluate combinations of liquid media obtained from agro-industrial residues and by-products, with solid media prepared with mixtures of grains and their derivatives, aiming to increase the production of JAB 02 and JAB 45 isolates of Lecanicillium lecanii. Sporulation, conidial viability and process yield were evaluated as well as the production costs using the JAB 45 isolate as a model system were analyzed. The production of JAB 02 was not increased using the biphasic culture. For JAB 45, some combinations provided an increase in yield, especially cheese whey with wheat bran and wheat grain, with lower production costs. Viability was not influenced by the production method, and the combinations showed no differences in the process yield. The biphasic method is suitable for the production of L. lecanii, and proves to be an appropriate technology to use in mass production by biofactories.

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The aim of the study is to evaluate the differences of protein binding of NAMI-A, a new ruthenium drug endowed with selective antimetastatic properties, and of cisplatin and to ascertain the possibility to use two drugs based on heavy metals in combination to treat solid tumour metastases. For this purpose, we have developed a technique that allows the proteins, to which metal drugs bind, to be identified from real protein mixtures. Following incubation with the drugs, the bands containing platinum and/or ruthenium are separated by native PAGE, SDS-PAGE and 2D gel electrophoresis, and identified using laser ablation inductively coupled plasma mass spectrometry. Both drugs interact with essentially the same proteins which, characterised by proteomics, are human serum albumin precursor, macroglobulin alpha 2 and human serotransferrin precursor. The interactions of NAMI-A are largely reversible whereas cisplatin forms stronger interactions that are less reversible. These data correlate well with the MCa mammary carcinoma model on which full doses of NAMI-A combined with cisplatin show additive effects as compared to each treatment taken alone, independently of whether NAMI-A precedes or follows cisplatin. Furthermore, the implication from this study is that the significantly lower toxicity of NAMI-A, compared to cisplatin, could be a consequence of differences in the mode of binding to plasma proteins, involving weaker interactions compared to cisplatin.

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Joint Publications from Iowa Engineering Experiment Station - Bulletin No. 190 and Iowa Highway Research Board - Bulletin No. 19. This bulletin is a report on the development of bituminous paving mixtures containing various local materials and asphaltic binders. The laboratory investigations described in this bulletin were performed as part of Iowa Highway Research Board project HR-20, "Treating Loess, Fine Sands, and Limestone Dusts With Liquid Binders." This project was awarded to the Iowa Engineering Experiment Station of Iowa State University in 1952, and continued to June, 1958.

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Most odors in natural environments are mixtures of several compounds. Perceptually, these can blend into a new "perfume," or some components may dominate as elements of the mixture. In order to understand such mixture interactions, it is necessary to study the events at the olfactory periphery, down to the level of single-odorant receptor cells. Does a strong ligand present at a low concentration outweigh the effect of weak ligands present at high concentrations? We used the fruit fly receptor dOr22a and a banana-like odor mixture as a model system. We show that an intermediate ligand at an intermediate concentration alone elicits the neuron's blend response, despite the presence of both weaker ligands at higher concentration, and of better ligands at lower concentration in the mixture. Because all of these components, when given alone, elicited significant responses, this reveals specific mixture processing already at the periphery. By measuring complete dose-response curves we show that these mixture effects can be fully explained by a model of syntopic interaction at a single-receptor binding site. Our data have important implications for how odor mixtures are processed in general, and what preprocessing occurs before the information reaches the brain.

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Certain areas of Iowa abound in loess, others contain soft limestones that are readily and cheaply available, and a large portion of the state is underlaid with sand. None of these materials is considered suitable in present practices for use in all-weather road construction. The loess is too fine and too difficult to handle; the limestones are considered too soft, and some of the harder ones unsound for this use; the sands are not naturally of the desired gradation and do not lend themselves to blending into satisfactory gradations. The purpose of this project is, therefore, to study and develop means and to determine the feasibility of using these materials, loess, fine sand, and soft limestones, either separately or in combinations in conjunction with liquid binders to produce paving mixtures applicable for all-weather road construction. Also included in the project was the development of methods of processing any of these materials, if necessary, to make them suitable for the desired purpose

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In 1982 the Iowa DOT allowed a successful bidder the option of submitting materials and proportions using fly ash to produce a portland cement concrete (PCC) paving mixture to meet a specified compressive strength. The contractor, Irving F. Jensen, received approval for the use of a concrete mixture utilizing 500 lbs. of portland cement and 88 lbs. of fly ash as a replacement of 88 lbs. of portland cement. The PCC mixture was utilized on the Muscatine County US 61 relocation bypass paved as project F-61-4(32)--20-70. A Class "C" fly ash obtained from the Chillicothe electric generating plant approximately 100 miles away was used in the project. This use of fly ash in lieu of portland cement resulted in a cost savings of $64,500 and an energy savings of approximately 16 billion BTU. The compressive strength of this PCC mixture option was very comparable to concrete mixtures produced without the use of fly ash. The pavement has been performing very well. The substitution of fly ash for 15% of the cement has been allowed as a contractor's option since 1984. Due to the cost savings, it has been used in almost all Iowa PCC paving since that time.