924 resultados para fraction addition


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Purpose: We aimed to determine the impact of SPECT/CT performed in addition to whole-­‐body scintigraphy augmented with prone lateral views in patients with well-­‐differentiated thyroid carcinoma. Methods and Materials: This retrospective study included 141 patients (87 female, 54 male, mean age 47 years) with well-­‐differentiated thyroid carcinoma (105 papillary, 31 follicular, 1 Hürthle cell and 4 poorly differentiated) treated with radioiodine therapy (1000-7400 MBq). Patients were referred for either first postsurgical therapy (n=76) or further treatment (n=65). Two nuclear medicine physicians interpreted the scans in consensus (first whole-­‐body scintigraphy with prone lateral view, then SPECT/CT) reporting abnormal iodine uptake in the thyroid bed, lymph nodes and distant metastasis. The corresponding ATA risk score was calculated for each patient before and after SPECT/CT, as well as change in disease extension Results: The analysis showed a difference between scintigraphy and SPECT/CT in n=17 lesions in 14 patients (9.9%): 12 were described as suspicious on scintigraphy and could be considered as benign on SPECT/CT (3 corresponded to local iodine uptake, 6 to lymph nodes metastases and 3 to distant metastases). The others 5 corresponded to metastases (4 lymph nodes and 1 distant) that were not seen on whole-­‐body scintigraphy augmented with prone lateral views. In 10 of 141 (7.1%) patients, we observed a change in ATA risk stratification, with a risk increase in 4 of them (2.8%). Conclusion: SPECT/CT allowed detecting 5 focal lesions missed on planar scintigraphy, and to precise benignity of 12 suspicious lesions on planar scintigraphy. Moreover, SPECT/CT improved the risk stratification in 10 patients with a significant change in the patient management

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Reactions of 2-acetylindole enolate with unsaturated oxazolopiperidones 3, 4 and 10 unexpectedly gives pentacyclic dilactams 6, 7 and 11, respectively, resulting from a domino-type process involving two successive conjugate additions and a final cyclization.

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The transport of macromolecules, such as low-density lipoprotein (LDL), and their accumulation in the layers of the arterial wall play a critical role in the creation and development of atherosclerosis. Atherosclerosis is a disease of large arteries e.g., the aorta, coronary, carotid, and other proximal arteries that involves a distinctive accumulation of LDL and other lipid-bearing materials in the arterial wall. Over time, plaque hardens and narrows the arteries. The flow of oxygen-rich blood to organs and other parts of the body is reduced. This can lead to serious problems, including heart attack, stroke, or even death. It has been proven that the accumulation of macromolecules in the arterial wall depends not only on the ease with which materials enter the wall, but also on the hindrance to the passage of materials out of the wall posed by underlying layers. Therefore, attention was drawn to the fact that the wall structure of large arteries is different than other vessels which are disease-resistant. Atherosclerosis tends to be localized in regions of curvature and branching in arteries where fluid shear stress (shear rate) and other fluid mechanical characteristics deviate from their normal spatial and temporal distribution patterns in straight vessels. On the other hand, the smooth muscle cells (SMCs) residing in the media layer of the arterial wall respond to mechanical stimuli, such as shear stress. Shear stress may affect SMC proliferation and migration from the media layer to intima. This occurs in atherosclerosis and intimal hyperplasia. The study of blood flow and other body fluids and of heat transport through the arterial wall is one of the advanced applications of porous media in recent years. The arterial wall may be modeled in both macroscopic (as a continuous porous medium) and microscopic scales (as a heterogeneous porous medium). In the present study, the governing equations of mass, heat and momentum transport have been solved for different species and interstitial fluid within the arterial wall by means of computational fluid dynamics (CFD). Simulation models are based on the finite element (FE) and finite volume (FV) methods. The wall structure has been modeled by assuming the wall layers as porous media with different properties. In order to study the heat transport through human tissues, the simulations have been carried out for a non-homogeneous model of porous media. The tissue is composed of blood vessels, cells, and an interstitium. The interstitium consists of interstitial fluid and extracellular fibers. Numerical simulations are performed in a two-dimensional (2D) model to realize the effect of the shape and configuration of the discrete phase on the convective and conductive features of heat transfer, e.g. the interstitium of biological tissues. On the other hand, the governing equations of momentum and mass transport have been solved in the heterogeneous porous media model of the media layer, which has a major role in the transport and accumulation of solutes across the arterial wall. The transport of Adenosine 5´-triphosphate (ATP) is simulated across the media layer as a benchmark to observe how SMCs affect on the species mass transport. In addition, the transport of interstitial fluid has been simulated while the deformation of the media layer (due to high blood pressure) and its constituents such as SMCs are also involved in the model. In this context, the effect of pressure variation on shear stress is investigated over SMCs induced by the interstitial flow both in 2D and three-dimensional (3D) geometries for the media layer. The influence of hypertension (high pressure) on the transport of lowdensity lipoprotein (LDL) through deformable arterial wall layers is also studied. This is due to the pressure-driven convective flow across the arterial wall. The intima and media layers are assumed as homogeneous porous media. The results of the present study reveal that ATP concentration over the surface of SMCs and within the bulk of the media layer is significantly dependent on the distribution of cells. Moreover, the shear stress magnitude and distribution over the SMC surface are affected by transmural pressure and the deformation of the media layer of the aorta wall. This work reflects the fact that the second or even subsequent layers of SMCs may bear shear stresses of the same order of magnitude as the first layer does if cells are arranged in an arbitrary manner. This study has brought new insights into the simulation of the arterial wall, as the previous simplifications have been ignored. The configurations of SMCs used here with elliptic cross sections of SMCs closely resemble the physiological conditions of cells. Moreover, the deformation of SMCs with high transmural pressure which follows the media layer compaction has been studied for the first time. On the other hand, results demonstrate that LDL concentration through the intima and media layers changes significantly as wall layers compress with transmural pressure. It was also noticed that the fraction of leaky junctions across the endothelial cells and the area fraction of fenestral pores over the internal elastic lamina affect the LDL distribution dramatically through the thoracic aorta wall. The simulation techniques introduced in this work can also trigger new ideas for simulating porous media involved in any biomedical, biomechanical, chemical, and environmental engineering applications.

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Microfibrillated cellulose (MFC) is known to enhance strength properties of paper. Improved strength usually means increased bonding which is strongly connected to dimensional instability of paper. Dimensional instability is due to changes in moisture content of paper; when paper is moistened it expands and when dried, it shrinks. Hygroexpansion is linked to end-use problems and excessive drying shrinkage consumes strength potential. Effective use of materials requires controlling of these phenomena. There isn’t yet data concerning dimensional stability of papers containing MFC which restricts wider use of MFC. Main objective of the work was to evaluate dimensional stability of wood-free paper containing different amounts of MFC. Sheets were dried with different methods to see how drying strains effected on drying shrinkage and hygroexpansion. Also tensile strength was measured to find out the effect of MFC. Results were compared to sheets containing kraft fines and in some test points cationic starch was used alongside with MFC. MFC increased the dimensional instability of freely dried sheets. As the amounts of MFC increased the effects on dimensional stability became more severe. However the fineness of MFC didn’t play any important role. Both hygroexpansion and drying shrinkage were decreased with cationic starch addition. Prevention of drying shrinkage over powered the effects of additives on hygroexpansion. Tensile strength improved up till 7 % addition amount which could be set as the upper limit of MFC addition when paper preparation and tensile strength are concerned.

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The stereoselective addition of the titanium (IV) enolates derived from (S)-4-isopropyl-N-4-chlorobutyryl-1,3-thiazolidine-2-thione (8) and from (S)-4-isopropyl-N-4-chloropentanoyl-1,3-thiazolidine-2-thione (9) to N-Boc-2-methoxypyrrolidine (5b) afforded the addition products (+)-10 and (+)-11 in 84% yield in both cases, as 8.6:1 and 10:1 diastereoisomeric mixtures, respectively. A three-step sequence allowed to convert these adducts to (+)-isoretronecanol (1) and (+)-5-epi-tashiromine (2) in 43% and 49% overall yield, respectively.

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Maytenus ilicifolia (Celastraceae) is a native plant of South America and popularly known as "espinheira-santa". The aim of this study was to evaluate the antioxidant capacity of extracts and isolated compounds from this plant. The antioxidant activity of the crude and semipurified extracts and isolated compounds was evaluated through DPPH-radical and phosphomolybdenum-complex assays. By both methods, the ethyl-acetate fraction demonstrated better antioxidant capacity compared with vitamin C and trolox. In the compounds, the higher the number of hydroxyls, the greater the antioxidant activity. In addition, stereochemistry influenced antioxidant activity, i.e., compounds with 2R,3R showed greater activity than those with 2R,3S.

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Chemical studies with aerial parts of Microgramma vacciniifolia (Langsd. & Fisch.) Copel. afforded ²-sitosterol, hopan-22-ol, 6-metoxiapinenin-7-O-²-D-allopyranoside and a mixture containing ethyl esters of carboxilic acids. The structures of the coumpounds were elucidated by spectroscopy and GC-MS analysis. The total phenolics contents of the crude extract and fractions were determined by Folin-Ciocalteau method. The antioxidant activity was evaluated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH). The AcOEt fraction showed better activity in DPPH assay (9.9 ± 0.03 µg/mL), and presented also higher contents of the total phenolic (93.60 ± 1.11 µg/mg). Antimicrobial and allelopathic effects of the crude etanolic extract and fractions also were evaluated. In addition, the combination of biological activities was discussed.

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Semi-hydrogenation of alkynes has industrial and academic relevance on a large scale. To increase the activity, selectivity and lifetime of monometallic catalysts, the development of bimetallic catalysts has been investigated. 1-Heptyne hydrogenation over low-loaded Pd and Ni monometallic and PdNi bimetallic catalysts was studied in liquid phase at mild conditions. XPS results suggest that nickel addition to Pd modifies the electronic state of palladium as nickel loading is increased. Low-loaded Pd catalysts showed the highest selectivities (> 95%). The most active prepared catalyst, PdNi(1%), was more selective than the Lindlar catalyst.

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Methanol steam reforming reaction was studied over Cu(5 wt.%)/CeO2 with and without the presence of Zn. The Zn addition decreased the Cu+2 reducibility and increased the oxygen mobility of ceria. The main products were CO2 and H2 with small amount of CO. Selectivity to CO decreased with the Zn addition and it was lower at lower reaction temperatures and lower space velocities. At 230 ºC and W/F MeOH = 648 g min mol-1 selectivities to H2 and to CO2 were 100% on Zn/Cu/Ce. The catalytic results indicated that CO was mainly a secondary product formed from reverse water gas shift reaction.

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Hemiselluloosat kuuluvat selluloosan ja ligniinin ohella puun ja muiden kasvimateriaalien päärakenneaineksiin. Hemiselluloosan kemiallisessa koostumuksessa on eroja kasvilajien välillä, mikä tekee ryhmästä hyvin monimuotoisen. Lehtipuiden pääasiallinen hemiselluloosa on glukuroniksylaani. Ksylaaneja esiintyy laajasti myös muissa kasveissa erilaisina rakenteina. Havupuiden yleisin hemiselluloosa on puolestaan galaktoglukomannaani. Arabinogalaktaani on erityisesti lehtikuusesta runsaana löytyvä hemiselluloosa, jota muissa puulajeissa on vain vähän. Luonnon polymeerejä tutkitaan jatkuvasti muun muassa vaihtoehtojen löytämiseksi raakaöljypohjaisille tuotteille. Aiemmin hemiselluloosia on pääosin hyödynnetty sellaisenaan tai jalostettu esimerkiksi sokereiksi. Selluloosan ja tärkkelyksen tavoin ne voivat kuitenkin toimia myös kemiallisen, fysikaalisen tai entsymaattisen muokkauksen lähtöaineena. Hemiselluloosien käyttöä rajoittaa usein se, että niiden eristäminen kasvimateriaalista hyvällä saannolla on vaikeaa. Useimmiten hemiselluloosa erotetaan biomassasta ligniinin poiston jälkeen uuttamalla erilaisilla reagensseilla, kuten emäksillä. Arabinogalaktaanin erottamiseen ei kuitenkaan vaadita ankaria olosuhteita, vaan yleisimmin siihen riittää uutto vedellä. Kalvosuodatus puolestaan on hyvä keino hemiselluloosan talteenottoon uuttoliuoksista. Tässä työssä tarkasteltiin arabinogalaktaanin erotusta siperianlehtikuusesta uuttokokein. Saadut uuttoliuokset konsentrointiin ja puhdistettiin kalvosuodatusmenetelmillä. Lisäksi tutkittiin eristetyn arabinogalaktaanin käyttöä kemiallisen muokkauksen lähtöaineena, missä pyrkimyksenä oli etenkin in situ -modifiointi suoraan uuttoliuoksessa oleville yhdisteille. Uuttokokeilla saatiin kuitenkin vain pieni osa lehtikuusen arabinogalaktaanista erotetuksi. Myös kalvosuodatusvaiheen aikana menetettiin osa uuttoliuosten arabinogalaktaanista. Koska arabinogalaktaanipitoisuus uuttoliuoksissa jäi hyvin alhaiseksi, in situ -modifiointeja oli vaikea saada onnistumaan. Uutto-olosuhteiden lisätutkimuksella sekä kiinnittämällä erityistä huomiota suodatuskalvojen valintaan voitaneen pitoisuutta nostaa ja saada lisämateriaalia kemiallista muokkausta varten.

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The Mg-vacancy binding free enthalpy of Al-Cr solid solution alloys with Mg addition was calculated by electrical resistivity measurements. The obtained value is lower than that obtained for dilute Al-Mg alloys with almost the same Mg content and may be attributed to the diffusion of Mg.

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Hydroksihapoille on olemassa useita käyttömahdollisuuksia teollisuudessa, joten niiden hyödyntäminen sellunvalmistuksen sivuvirrasta eli mustalipeästä on suuren kiinnostuksen kohteena. Tässä työssä selvitettiin, onko hydroksihappojen erotus ja puhdistus mustalipeästä mahdollista nanosuodatuksella. Kokeellisessa osassa suodatettiin emäksisen mustalipeän lisäksi hapotettua ja jäähdytyskiteytettyä mustalipeää, johon oli lisätty liuotinta. Mustalipeäsuodatuksissa käytettiin viittä erilaista nanosuodatusmembraania (Microdyn Nadir® NP010 ja NP030, Dow Chemical Company NF-90, Woongjin Chemical NE-70 sekä Ge-Osmonics Desal 5 DK). Kirjallisuusosassa käsiteltiin puun sisältämien yhdisteiden kemiallista koostumusta, sellun valmistuksen pääperiaatteita, mustalipeän ja hydroksihappojen ominaisuuksia sekä hydroksihappojen käyttömahdollisuuksia. Lisäksi tarkasteltiin erilaisia hydroksihappojen erotusmenetelmiä, nanosuodatuksen teoriaa ja prosessiin sopivan membraanin valintakriteerejä. Työn kokeellisessa osassa tutkittiin emäksisen mustalipeän monivaiheisen nanosuodatuksen tehokkuutta hydroksihappojen erotuksessa. Hapotetun ja jäähdytyskiteytetyn mustalipeän suodatuskokeissa tutkittiin erityyppisten membraanien erotuskykyä sekä syötön liuotinlisäyksen vaikutusta hydroksihappojen erottumiseen. Lisäksi tarkasteltiin membraanien kestävyyttä ja foulaantumista suodatusolosuhteissa. Työn tulokset osoittivat, että hydroksihappoja voidaan fraktioida mustalipeästä nanosuodatuksella. Hydroksihappojen fraktiointiin vaikuttaa merkittävästi mustalipeässä käytetyn liuottimen läsnäolo sekä suodatuspaine. Lisäksi koetulosten perusteella havaittiin, että monivaiheisella nanosuodatuksella hydroksihapot läpäisevät membraanin ja permeaattiin saavutetaan puhtaampi happojae.

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The objectives of the work were to study the effect of dewatering time varying on formation properties of papersheets, to determine the role of fines fraction in creation of paper with good formation and strength properties of papersheets, and also to study the effect of charge modification of fibers fractionations on formation properties of handsheets. The paper formation is one of the most important structural properties of paper. This property has effect on physical and optical characteristics of paper. In thi work the effect of formation on tensile strength was determined. The formation properties were analyzed by using the AMBERTEC Beta Formation Tester. The PAM addition as a f;locculant agent did some changes in the formation of paper. Paper sheets were also made from different furnishes of both birch and pine pulps. The fibers particles as a fines have great effect on drainability changes. Fines fraction played important role in papermaking. The two kinds of pulps (pine and birch pulps) were also used in this work for investigation of fines role. As it was expected the fines fraction gave positive effect on paper formation, but when fines fraction was added above initial fines content the formation of paper was deteriorated. The effect of paper formation on tensile strength was also determined. In many cases the poor formation of paper had negative effect on strength properties of paper..

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Coffee production was closely linked to the economic development of Brazil and, even today, coffee is an important product of the national agriculture. The State of Minas Gerais currently accounts for 52% of the whole coffee area in Brazil. Remote sensing data can provide information for monitoring and mapping of coffee crops, faster and cheaper than conventional methods. In this context, the objective of this study was to assess the effectiveness of coffee crop mapping in Monte Santo de Minas municipality, Minas Gerais State, Brazil, from fraction images derived from MODIS data, in both dry and rainy seasons. The Spectral Linear Mixing Model was used to derive fraction images of soil, coffee, and water/shade. These fraction images served as input data for the supervised automatic classification using the SVM - Support Vector Machine approach. The best results concerning Overall Accuracy and Kappa Index were obtained in the classification of the dry season, with 67% and 0.41, respectively.

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ABSTRACT This paper studied the effect of adding an enzyme (ellulose) on anaerobic digestion of maize silage. We compared materials at chopping lengths of 8 mm (MSL), 4mm (MSS) and natural size (Ms) under a mesophilic and discontinuous operation (batch process). Hence, we found the process to be significantly influenced by particle size. Moreover, the ellulose addition did not significantly impact biogas production after a 35-day digestion period. Ms and MSS displayed an improved response to all variables when compared with MSL and MSL+C, with significant differences. Studies on the refractory fraction at infinite time (R0) have demonstrated that the lowest values correspond to Ms and MSS (0.122 and 0.155, respectively). The Kinetic approach and the Ultimate Biodegradability test are useful tools to evaluate the effect of the addition of an enzyme to the anaerobic process.