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Rheological behavior of blood in Wistar rats with different total cholesterol levels
Medina-Torres Luis,Calderas Fausto,Calderas Fausto,Núñez–Ramírez Diola-Marina,Castro Andrés Navarrete,Bernad-Bernad Ma. Josefa,Manero Octavio 한국유변학회 2022 Korea-Australia rheology journal Vol.34 No.4
Blood is a rheologically complex suspension, in which the soluble fraction contains proteins, total cholesterol and triglycerides. The blood rheological behavior is strongly affected by the concentration of these components. This work evaluates the total cholesterol effect on the rheological behavior of Wistar rat blood by means of an in vitro study. Twenty-one rats were divided into 3 groups, each one had an assigned diet with different fat content: reference group (RG) with 3%, medium fat content group (MG) with 4.5% and high-fat content group (HG) with 6.5%; in the latter group, mixed-vegetable fat was added. From each group, intraocular representative blood samples were taken with time lapse of 15 days between each sampling followed by biochemical and hemo-rheological tests. The first analysis detected changes in total cholesterol levels, attributed to the rat metabolism, formation of adipose tissue and competition for food. The second test consisted in steady simple-shear and linear oscillatory flow. The linear viscoelastic spectra reveal that the viscous modulus is larger than the elastic modulus (G > G′), with simple-shear viscosity exhibiting shear-thinning behavior. An important finding is a pseudo-solid- like behavior at low frequencies (1 rad/s) akin to the presence of yield stresses in the high-fat content group after 30 days, revealing strong interactions between total cholesterol levels and blood cells. The hemo-rheological tests represent a promising alternative to identify pathologies present in the blood (total cholesterol, digestive problems, and diabetes).
Prototype of a Computer Vision-Based CubeSat Detection System for Laser Communications
I. Medina,J. J. Hernández-Gómez,C. R. Torres-San Miguel,L. Santiago,C. Couder-Castañeda 한국항공우주학회 2021 International Journal of Aeronautical and Space Sc Vol.22 No.3
Up to now, CubeSat nano-satellites have strong limitations in communication data rates (∼100 ∼100 kbps) and bandwidth due to the strictness of CubeSat standard. However, if they could be endowed with optical communications (data rates up to 1 Gbps in optimal state), CubeSat applications would exponentially increase. Nonetheless, laser communications face some important drawbacks as the development of a very strict and accurate tracking mechanism. This work proposes an on-board fine pointing system to locate an optical ground station beacon using an embedded system complying with the restrictive CubeSat standard. Such on-board fine pointing system works based on computer vision. The experimental prototype is implemented in Matlab/Simulink, within a Raspberry Pi 3B. The main outcome is the usage of off-the-shelf components (COTS), obtaining an efficient tracking with low power consumption in very noisy and reflective environments. The developed system proves to be fast, stable and strong. It also satisfies the strict size and power consumption restrictions of CubeSat standard.
Tanomaru-Filho, Mario,Torres, Fernanda Ferrari Esteves,Pinto, Jader Camilo,Santos-Junior, Airton Oliveira,Tavares, Karina Ines Medina Carita,Guerreiro-Tanomaru, Juliane Maria The Korean Academy of Conservative Dentistry 2020 Restorative Dentistry & Endodontics Vol.45 No.3
Objectives: This study evaluated by using micro-computed tomography (micro-CT) the filling ability and sealer apical extrusion promoted by a new Sealer Injection System (SIS; Angelus) with side openings needle, in comparison with the conventional injection system, associated with a new ready-to-use calcium silicate-based sealer (Bio-C Sealer). Materials and Methods: Acrylic resin models containing a main curved artificial canal and 3 simulated lateral canals in apical, middle and cervical thirds were used. The main root canals were prepared using a rotary system up to size 35.05. The canals were filled with Bio-C sealer by using a single cone technique and the conventional delivery system or SIS. Samples were scanned in micro-CT. The percentage of voids throughout the entire extension of the main root canal and in each third of the lateral canals, besides the apical extrusion of the sealer was calculated. Data were submitted to t-test (p < 0.05). Results: There was no difference between both systems in the main root canals filling. Although the volume percentage of voids was similar in the apical and middle thirds of lateral canals, SIS had the greatest filling ability of the cervical third lateral canal. Moreover, the conventional system showed the highest apical extrusion of the sealer. Conclusions: The conventional and SIS obturation systems had an appropriate filling ability of the main root canal. SIS had the best filling of the cervical third of the lateral canals, besides lower sealer apical extrusion, suggesting its clinical indication.
Combination of a new ultrasonic tip with rotary systems for the preparation of flattened root canals
Tavares Karina Ines Medina Carita,Pinto Jáder Camilo,Santos-Junior Airton Oliveira,Esteves Torres Fernanda Ferrari,Guerreiro-Tanomaru Juliane Maria,Tanomaru-Filho Mario 대한치과보존학회 2021 Restorative Dentistry & Endodontics Vol.46 No.4
Objectives This study evaluated 2 nickel-titanium rotary systems and a complementary protocol with an ultrasonic tip and a small-diameter instrument in flattened root canals. Materials and Methods Thirty-two human maxillary second premolars with flattened canals (buccolingual diameter ≥4 times larger than the mesiodistal diameter) at 9 mm from the radiographic apex were selected. The root canals were prepared by ProDesign Logic (PDL) 30/0.01 and 30/0.05 or Hyflex EDM (HEDM) 10/0.05 and 25/0.08 (n = 16), followed by application of the Flatsonic ultrasonic tip in the cervical and middle thirds and a PDL 25/0.03 file in the apical third (FPDL). The teeth were scanned using micro-computed tomography before and after the procedures. The percentage of volume increase, debris, and uninstrumented surface area were analyzed using the Kruskal-Wallis, Dunn, Wilcoxon, analysis of variance/Tukey, and paired and unpaired t-tests (α = 0.05). Results No significant difference was found in the volume increase and uninstrumented surface area between PDL and HEDM (p > 0.05). PDL had a higher percentage of debris than HEDM in the middle and apical thirds (p < 0.05). The FPDL protocol resulted in less debris and uninstrumented surface area for PDL and HEDM (p < 0.05). This protocol, with HEDM, reduced debris in the middle and apical thirds and uninstrumented surface area in the apical third (p < 0.05). Conclusions High percentages of debris and uninstrumented surface area were observed after preparation of flattened root canals. The HEDM, Flatsonic tip, and 25/0.03 instrument protocol enhanced cleaning in flattened root canals.
Rheology and gel point of the enzymatic hydrolysis of urea in the presence of urease
R. Serrato-Millán,L. Medina-Torres,F. Calderas,B.L. España-Sánchez,M. Estevez,A.R. Hernandez-Martínez,M. Cruz-Soto,I.C. Sánchez,R. Gómez-García,I. Sánchez-Betancourt,M.C. Velasquillo-Martínez,G. Luna- 한국유변학회 2017 Korea-Australia rheology journal Vol.29 No.1
This study reports on the rheology of the gelation kinetics of raw chitosan (CTS) solutions (2% w/v) produced by enzymatic hydrolysis of urea at different urea concentrations (40, 50, 60, 80, and 100 mM) in the presence of urease at 1 U/mL. Viscoelastic parameters and pH values were evaluated during gelation process and the rheological properties of CTS hydrogels produced were monitored after 24 h at 37°C to simulate human body temperatures. pH measurements suggest that above some critical urea concentration (50 mM) the time required (tgel) to reach the critical pH gelation shows no dependence on urea concentration (tgel was ca. 70 minutes). Above 50 mM of urea concentration, CTS hydrogels exhibit an elastic modulus G' higher than the viscous modulus G'' with no frequency dependence characteristic of a gel behavior. Gelation kinetics analyzed by rheology suggest that the G' (i.e., structure) development depends on urea concentration during solution neutralization.
Nunez-Ramirez, Diola Marina,Medina-Torres, Luis,Valencia-Lopez, Jose Javier,Calderas, Fausto,Lopez-Miranda, Javier,Medrano-Roldan, Hiram,Solis-Soto, Aquiles The Korean Society for Microbiology and Biotechnol 2012 Journal of microbiology and biotechnology Vol.22 No.11
Fermentation with filamentous fungi in a bioreactor is a complex dynamic process that is affected by flow conditions and the evolution of the rheological properties of the medium. These properties are mainly affected by the biomass concentration and the morphology of the fungus. In this work, the rheological properties of a fermentation with the fungus Beauveria bassiana under different hydrodynamic conditions were studied and the rheological behavior of this broth was simulated through a mixture of carboxymethyl cellulose sodium and cellulose fibers (CMCNa-SF). The bioreactor was a 10 L CSTR tank operated at different stir velocities. Rheological results were similar at 100 and 300 rpm for both systems. However, there was a significant increase in the viscosity accompanied by a change in the consistence index, calculated according to the power law model, for both systems at 800 rpm. The systems exhibited shear-thinning behavior at all stir velocities, which was determined with the power law model. The mixing time was observed to increase as the cellulose content in the system increased and, consequently, the efficiency of mixing diminished. These results are thought to be due to the rheological and morphological similarities of the two fungal systems. These results will help in the optimization of scale-up production of these fungi.
Diana Penagos-Calvete,Jonathan Guauque-Medina,María Francisca Villegas-Torres,Guillermo Montoya 한국원예학회 2019 Horticulture, Environment, and Biotechnology Vol.60 No.2
Capsicum is currently one of the highest value vegetable crops due its richness in vitamins and antioxidants and is frequentlycommercialized as fresh fruit, dry crushed pepper, paprika oleoresin or pepper paste. The chemical content comprisescarotenoids, fl avonoids, lipid molecules like fatty acids, triacylglycerides and capsaicinoids as its principal chemotaxonomicmarkers. However, triacylglycerides and carotenoids are no frequently taken into analytical spectrometric methods due tononvolatile and extreme low polarity properties. Those molecules are usually extracted and commercialized as oleoresin,and there are gaining attention because it helps to combat nutrient defi ciencies. This study monitors the behavior of thepungency value in two real industrial productive crops of Capsicum frutescens (tabasco) and Capsicum annuum (cayenne)during a complete harvest period. A comparison of chemical carotenoid and triacylglycerides profi le was carried out byUPLC–PDA–ESI–MS between Capsicum frutescens (tabasco), Capsicum chinense (habanero), Capsicum annuum (jalapeño),and Capsicum annuum (serrano) in two diff erent ripening stages. The authors’ main fi nding is a strong correlation betweenplant age and pungency level independent of the size and dehydration state of the fruits. The major carotenoid content wasfounded in red Tabasco variety, and 12 triacylglycerides and 10 esterifi ed carotenoids are reported along the all fruits treated. Our results present an important and alternative fi nding for agro-industrial chili pepper producers and marketers who need tobetter understand the behavior of the pungency value as the principal quality feature, and to discover added-value chemicalslike TAG and carotenoids in their products.
On the yield stress of complex materials
F. Calderas,E. E. Herrera-Valencia,A. Sanchez-Solis,O. Manero,L. Medina-Torres,A. Renteria,G. Sanchez-Olivares 한국유변학회 2013 Korea-Australia rheology journal Vol.25 No.4
In the present work, the yield stress of complex materials is analyzed and modeled using the Bautista-Manero-Puig (BMP) constitutive equation, consisting of the upper-convected Maxwell equation coupled to a kinetic equation to account for the breakdown and reformation of the fluid structure. BMP model predictions for a complex fluid in different flow situations are analyzed and compared with yield stress predictions of other rheological models, and with experiments on fluids that exhibit yield stresses. It is shown that one of the main features of the BMP model is that it predicts a real yield stress (elastic solid or Hookean behavior) as one of the material parameters, the zero shear-rate fluidity, is zero. In addition, the transition to fluid-like behavior is continuous, as opposed to predictions of more empirical models.
Effect of cholesterol and triglycerides levels on the rheological behavior of human blood
Leonardo Moreno,Fausto Calderas,Guadalupe Sanchez-Olivares,Luis Medina-Torres,Antonio Sanchez-Solis,Octavio Manero 한국유변학회 2015 Korea-Australia rheology journal Vol.27 No.1
Important public health problems worldwide such as obesity, diabetes, hyperlipidemia and coronary diseases are quite common. These problems arise from numerous factors, such as hyper-caloric diets, sedentary habits and other epigenetic factors. With respect to Mexico, the population reference values of total cholesterol in plasma are around 200 mg/dL. However, a large proportion has higher levels than this reference value. In this work, we analyze the rheological properties of human blood obtained from 20 donors, as a function of cholesterol and triglyceride levels, upon a protocol previously approved by the health authorities. Samples with high and low cholesterol and triglyceride levels were selected and analyzed by simple-continuous and linear-oscillatory shear flow. Rheometric properties were measured and related to the structure and composition of human blood. In addition, rheometric data were modeled by using several constitutive equations: Bautista-Manero-Puig (BMP) and the multimodal Maxwell equations to predict the flow behavior of human blood. Finally, a comparison was made among various models, namely, the BMP, Carreau and Quemada equations for simple shear rate flow. An important relationship was found between cholesterol, triglycerides and the structure of human blood. Results show that blood with high cholesterol levels (400 mg/dL) has flow properties fully different (higher viscosity and a more pseudo-plastic behavior) than blood with lower levels of cholesterol (tendency to Newtonian behavior or viscosity plateau at low shear rates)