1000 resultados para cytotoxicity test
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The 6-minute walk test (6MWT) is a simple field test that is widely used in clinical settings to assess functional exercise capacity. However, studies with healthy subjects are scarce. We hypothesized that the 6MWT might be useful to assess exercise capacity in healthy subjects. The purpose of this study was to evaluate 6MWT intensity in middle-aged and older adults, as well as to develop a simple equation to predict oxygen uptake ( V ˙ O 2 ) from the 6-min walk distance (6MWD). Eighty-six participants, 40 men and 46 women, 40-74 years of age and with a mean body mass index of 28±6 kg/m2, performed the 6MWT according to American Thoracic Society guidelines. Physiological responses were evaluated during the 6MWT using a K4b2 Cosmed telemetry gas analyzer. On a different occasion, the subjects performed ramp protocol cardiopulmonary exercise testing (CPET) on a treadmill. Peak V ˙ O 2 in the 6MWT corresponded to 78±13% of the peak V ˙ O 2 during CPET, and the maximum heart rate corresponded to 80±23% of that obtained in CPET. Peak V ˙ O 2 in CPET was adequately predicted by the 6MWD by a linear regression equation: V ˙ O 2 mL·min-1·kg-1 = -2.863 + (0.0563×6MWDm) (R2=0.76). The 6MWT represents a moderate-to-high intensity activity in middle-aged and older adults and proved to be useful for predicting cardiorespiratory fitness in the present study. Our results suggest that the 6MWT may also be useful in asymptomatic individuals, and its use in walk-based conditioning programs should be encouraged.
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This study aimed to verify the association between the contribution of energy systems during an incremental exercise test (IET), pacing, and performance during a 10-km running time trial. Thirteen male recreational runners completed an incremental exercise test on a treadmill to determine the respiratory compensation point (RCP), maximal oxygen uptake (V˙O2max), peak treadmill speed (PTS), and energy systems contribution; and a 10-km running time trial (T10-km) to determine endurance performance. The fractions of the aerobic (WAER) and glycolytic (WGLYCOL) contributions were calculated for each stage based on the oxygen uptake and the oxygen energy equivalents derived by blood lactate accumulation, respectively. Total metabolic demand (WTOTAL) was the sum of these two energy systems. Endurance performance during the T10-km was moderately correlated with RCP, V˙O2maxand PTS (P<@0.05), and moderate-to-highly correlated with WAER, WGLYCOL, and WTOTAL (P<0.05). In addition, WAER, WGLYCOL, and WTOTAL were also significantly correlated with running speed in the middle (P<0.01) and final (P<0.01) sections of the T10-km. These findings suggest that the assessment of energy contribution during IET is potentially useful as an alternative variable in the evaluation of endurance runners, especially because of its relationship with specific parts of a long-distance race.
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This study aimed to analyze the agreement between measurements of unloaded oxygen uptake and peak oxygen uptake based on equations proposed by Wasserman and on real measurements directly obtained with the ergospirometry system. We performed an incremental cardiopulmonary exercise test (CPET), which was applied to two groups of sedentary male subjects: one apparently healthy group (HG, n=12) and the other had stable coronary artery disease (n=16). The mean age in the HG was 47±4 years and that in the coronary artery disease group (CG) was 57±8 years. Both groups performed CPET on a cycle ergometer with a ramp-type protocol at an intensity that was calculated according to the Wasserman equation. In the HG, there was no significant difference between measurements predicted by the formula and real measurements obtained in CPET in the unloaded condition. However, at peak effort, a significant difference was observed between oxygen uptake (V˙O2)peak(predicted)and V˙O2peak(real)(nonparametric Wilcoxon test). In the CG, there was a significant difference of 116.26 mL/min between the predicted values by the formula and the real values obtained in the unloaded condition. A significant difference in peak effort was found, where V˙O2peak(real)was 40% lower than V˙O2peak(predicted)(nonparametric Wilcoxon test). There was no agreement between the real and predicted measurements as analyzed by Lin’s coefficient or the Bland and Altman model. The Wasserman formula does not appear to be appropriate for prediction of functional capacity of volunteers. Therefore, this formula cannot precisely predict the increase in power in incremental CPET on a cycle ergometer.
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Suomen osakeyhtiölain mukaan varoja ei saa jakaa, jos jaosta päätettäessä tiedetään tai pitäisi tietää yhtiön olevan maksukyvytön tai jaon aiheuttavan maksukyvyttömyyden. Ongelmallista on, että maksukykyä ei ole selvästi määritelty laissa tai hallituksen esityksessä. Tilintarkastuslain mukaan tilintarkastajan on siten huomautettava, jos maksukykytestiä on rikottu, mutta tilintarkastaja joutuu yleensä määrittelemään tällaiset huomauttamista vaativat tilanteet itse. Maksukykytestistä on kirjoitettu suomalaisessa yhtiöoikeuden ja laskentatoimen kirjallisuudessa melko kattavasti. Kuitenkin tilintarkastajaa koskeva näkökulma on saanut osakseen suhteellisen vähän huomiota. Tästä näkökulmasta on kirjoitettu vain joitakin korkeakoulujen tutkielmia sekä lyhyehköjä ammatillisia seminaariesityksiä. Tämän tutkielman tavoitteena on ollut koota laaja yleiskuva siitä, miten tilintarkastajat itse kokevat asemansa ja tehtävänsä yllä kuvatuissa tilanteessa. Tutkielmassa on käyty läpi aikaisempaa yhtiöoikeuden ja laskentatoimen kirjallisuudessa ja seminaariesityksissä esitettyä aineistoa. Lisäksi tutkielmaa varten tehtiin suomalaisille tilintarkastajille kohdennettu Internet-pohjainen kysely. Tutkielma selkeyttää kuvaa siitä, miten tilintarkastajat toimivat yllä kuvatussa tilanteessa ja miten he ovat sopeuttaneet toimiaan yhteiskunnan institutionaalisen asetelman muututtua. Kirjallisuuden pohjalta tapahtuva teoreettinen analyysi on yhdistetty kyselyyn siitä, miten tilintarkastajat käytännössä toimivat. Tutkimuksen perustana olevaa tietoa on analysoitu pääosin kyselytutkimuksen menetelmin, mutta myös tilastollisen tutkimuksen menetelmiä on käytetty. Tutkielman tuloksena tutkielmassa selvitetään tilintarkastajan tehtäviä maksukykytestin yhteydessä. Tuloksena voidaan myös todeta, että tilintarkastaja ei suorita varojenjaossa tarvittavan maksukyvyn arvioinnin kannalta keskeisiä tarkastustoimenpiteitä ainoastaan tilikauden päättymisen jälkeen. Päinvastoin, tällaisia tarkastustoimenpiteitä suoritetaan enemmän tai vähemmän koko tilintarkastuksen aikana. Lisäksi vaikuttaisi siltä, että tilintarkastajan oma suhtautuminen maksukykytestiin on ainakin jossain määrin merkityksellinen sen kannalta, kuinka paljon tarkastustoimenpiteitä tehdään ja kuinka paljon maksukyvystä ja siihen liittyvistä puutteista raportoidaan yhtiön johdolle.
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Annona crassiflora (araticum), Eugenia dysenterica (cagaita), and Caryocar brasiliense (pequi) are tropical fruits of the second biggest Brazilian biome: the cerrado. Nowadays, the cerrado faces two different realities: 1) the great possibility of food production since it is considered as the biggest storehouse of the world; and 2) the rich biodiversity that has been newly discovered and known. Previous studies showed that certain cerrado fruits demonstrate high content of total phenols and excellent antioxidant activity in in vitro models. Moreover, using fingerprinting analysis, important bioactive molecules were identified as probably responsible for their antioxidant activity. In this study, the cytotoxicity and phototocixity of ethanolic extracts from cerrado fruits were evaluated using the in vitro Neutral Red Uptake (NRU). Regarding cytotoxicity, the extracts of araticum peel and cagaita seed did not shown any cytotoxic potential up to 300 µg.mL-1. Ethanolic extracts of araticum seed and pequi peel presented low cytotoxic potential and, according to linear regressions, the estimated LD50 were de 831.6 and 2840.7 mg.kg-1, respectively. In the evaluated conditions, only the araticum peel extract presented a phototoxic potential. This is the first attempt to screen the toxicity of cerrado fruits with high antioxidant activity.
Cytotoxicity and mutagenicity of cola and grape flavored soft drinks in bone marrow cells of rodents
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Due to the large consumption of soft drinks in Brazil and worldwide in recent years and considering that some of the components present in their composition pose potential risks to human health, the aim of this study was to evaluate the cytotoxic and mutagenic potential of specific cola and grape-flavored soft drink brands. Bone marrow cells of Wistar rats were initially treated by gavage with one single dose of Cola or Grape soft drink, which was next offered ad libitum (instead of water) for 24 hours. A negative control treatment was performed by administering one single dose of water and a positive control administering cyclophosphamide intraperitoneally. Statistical analysis showed that the Cola and Grape soft drinks studied were not cytotoxic. However, the Cola soft drink proved mutagenic in this experiment treatment time. Therefore, this study serves as a warning about the consumption of Cola-flavored soft drink and for the need for further subchronic and chronic studies on soft drinks in order to evaluate the long term mutagenic and cytotoxic effects of these substances.
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The objective of this study was to evaluate the cytotoxic effect of the food dyes sunset yellow, bordeaux red, and tartrazine yellow on the cellular cycle of Allium cepa L. Each dye was evaluated at the doses of 0.4 and 4.0 mL, at the exposure times of 24 and 48 hours in root tip cells of Allium cepa L. Slides were prepared and cells were analyzed during the whole cell cycle for cellular aberrations totaling 5,000 total cells for each dose evaluated. The mitotic index was calculated, and statistical analysis was performed using the Chi-squared test (p < 0.05). The results showed that the three dyes used under the evaluated doses and exposure times were cytotoxic to the cells of the system-test used. Further cytotoxicity studies should be conducted for additional results and a proper evaluation of the effect of these three dyes on a cellular level.
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The aim of this work was to calibrate the material properties including strength and strain values for different material zones of ultra-high strength steel (UHSS) welded joints under monotonic static loading. The UHSS is heat sensitive and softens by heat due to welding, the affected zone is heat affected zone (HAZ). In this regard, cylindrical specimens were cut out from welded joints of Strenx® 960 MC and Strenx® Tube 960 MH, were examined by tensile test. The hardness values of specimens’ cross section were measured. Using correlations between hardness and strength, initial material properties were obtained. The same size specimen with different zones of material same as real specimen were created and defined in finite element method (FEM) software with commercial brand Abaqus 6.14-1. The loading and boundary conditions were defined considering tensile test values. Using initial material properties made of hardness-strength correlations (true stress-strain values) as Abaqus main input, FEM is utilized to simulate the tensile test process. By comparing FEM Abaqus results with measured results of tensile test, initial material properties will be revised and reused as software input to be fully calibrated in such a way that FEM results and tensile test results deviate minimum. Two type of different S960 were used including 960 MC plates, and structural hollow section 960 MH X-joint. The joint is welded by BöhlerTM X96 filler material. In welded joints, typically the following zones appear: Weld (WEL), Heat affected zone (HAZ) coarse grained (HCG) and fine grained (HFG), annealed zone, and base material (BaM). Results showed that: The HAZ zone is softened due to heat input while welding. For all the specimens, the softened zone’s strength is decreased and makes it a weakest zone where fracture happens while loading. Stress concentration of a notched specimen can represent the properties of notched zone. The load-displacement diagram from FEM modeling matches with the experiments by the calibrated material properties by compromising two correlations of hardness and strength.
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Freshly harvested triticale seeds are usually dormant, making the immediate evaluation of the physiological potential of seed lots difficult. We evaluated different triphenyl tetrazolium chloride (TTC) test methods for rapidly determining the viability of four seed lots of x.Triticosecale Wittmack cultivar IPR111. The test variables were: Preconditioning, (i) placing whole seeds between moistened paper towels or (ii) directly soaking the seeds in water, both procedures being conducted at 20 ºC for 18 hours; Post-conditioning seed preparation, (i) longitudinal bisection of the seed through the embryo with one half being stained and the other discarded or (ii) longitudinal bisection with both halves being stained; Staining for three and four hours, in the dark, with 0.1%, 0.5% or 1.0% (w/v) TTC according to the preconditioning method described above, (i) both halves of each seed were placed on filter paper moistened with TTC and maintained at 40 ºC or (ii) one half of each seed was immersed in 5 mL of TTC solution in a 100 mL glass beaker at 30 ºC. The best results were obtained by preconditioning seeds between moistened paper towels at 20 ºC for 18 hours and staining on filter paper with 1.0% (w/v) TTC for three hours at 40 ºC.
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The tetrazolium test is used to control seed quality of various plant species since it allows a rapid evaluation of viability. Freshly harvested barley seeds show dormancy that can make the germination test ineffective for an immediate evaluation. Therefore, the development of more efficient methods, such as the tetrazolium test, is necessary. The objective of this research work was to study various procedures for performing the tetrazolium test on barley seeds. Five lots of cv. BRS 195 barley seeds were used and subjected to the following treatments: two different methods of seed preconditioning (direct immersion in H2O and between sheets of moistened paper towels); two types of preparation for staining (longitudinal cross-section of the seed through the embryo with immersion of one half in a 2,3,5 triphenyl tetrazolium chloride solution or placing both halves on top of filter paper moistened with the tetrazolium salt solution); two methods of staining (on top of filter paper and direct immersion in the tetrazolium salt solution). Three concentrations of the tetrazolium salt solution (0.1%, 0.5%, and 1.0%) were used. It was concluded that the tetrazolium test on barley seeds may be accomplished with preconditioning by direct immersion in H2O and staining by immersing in a 0.1% or 0.5% concentration of tetrazolium salt solution or staining on top of filter paper moistened with such solution at a 1.0% concentration.
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Coffee seeds have slow and irregular germination, losing fast their viability during storage, and the standard germination test of these seeds requires at least 30 days. Besides, the results may not reflect the actual physiological quality of these seeds. The objective of this work was to develop a fast and practical test for evaluating the viability of coffee seeds, which is based on the interpretation of different color hues of exudates from seeds. Coffee seeds of the cultivar Catuai 44 from six lots were submitted to germination, accelerated aging, and electrical conductivity tests. In the exudates color hue test, coffee seeds without the parchment and the silvery pellicle (four replications of 10 seeds each) were distributed on top of paper towels moistened and then maintained into a germinator, at 25 ºC for 24, 48, 72, 96, and 120 h. Three classes of color hues were established: colorless, light color hue, and dark color hue, assigning the values of 0, 1, and 3, for each class, respectively. The proposed exudates color hue test can be recommended for the fast assessment of viability for coffee seeds. The most promising results were obtained for seeds with 12% moisture content, after imbibition periods of 72, 96, and 120 h; and with 30% moisture content, after imbibition periods of 72 and 120 h.
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Today, the user experience and usability in software application are becoming a major design issue due to the adaptation of many processes using new technologies. Therefore, the study of the user experience and usability might be included in every software development project and, thus, they should be tested to get traceable results. As a result of different testing methods to evaluate the concepts, a non-expert on the topic might have doubts on which option he/she should opt for and how to interpret the outcomes of the process. This work aims to create a process to ease the whole testing methodology based on the process created by Seffah et al. and a supporting software tool to follow the procedure of these testing methods for the user experience and usability.
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Banco del conocimiento
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Banco del conocimiento
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Desarrollo empresarial y creación de empresa