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Thermal shock resistance of mullite/Sr-celsian/zirconia composites
Rodríguez-Salazar P.,Almanza-Robles J. M.,Cortés-Hernández D. A.,Escobedo-Bocardo J. C. 한국세라믹학회 2022 한국세라믹학회지 Vol.59 No.6
The thermal shock resistance of novel mullite /Sr-celsian /zirconia composites was studied. The eff ect of the Sr-celsian (15, 20, 25 wt.%) and ZrO 2 (5, 15, 25 wt.%) amounts on the thermal shock resistance, was evaluated. The composites were obtained at 1450 °C. Thermal shock resistance was performed by heating samples up to a selected temperature (∆ T = 200–1000 °C) and then suddenly immersed in water. After testing, the bending strength was evaluated and the results were statistically analyzed using Minitab with a confi dence level of 0.05. Pareto charts showed that Sr-celsian and zirconia content have the highest infl uence on fl exural strength after thermal shock. The highest thermal shock resistance was obtained for the composites with the highest amount of zirconia and Sr-celsian. Most of the composites showed a decrease in strength of around 75%. The strength of the composites with 20 or 25 wt.% of celsian and 25 wt.% zirconia increased at ∆ T of 1000 °C. The Pareto chart for these composites showed that zirconia has the highest eff ect on strength. A change in expansion is shown between 800 and 900 °C, indicating the transformation of monoclinic to tetragonal zirconia. This transformation generates microc- racks that defl ect cracks generated during thermal stress. Also, residual stresses are generated during cooling which plays a role in absorbing the energy of a generated crack. The strontium celsian forms an interlocked microstructure that improves strength. These composites are promising materials for applications in which sudden and extreme temperature changes occur.
Synthesis by a solid state reaction of the Sr4Al6O12SO4 compound
J.A. Rodríguez-García,E. Rocha-Rangel,J. Torres-Torres,J. M. Almanza-Robles 한양대학교 세라믹연구소 2011 Journal of Ceramic Processing Research Vol.12 No.3
The synthesis and formation of Sr4Al6O12SO4 in the system SrCO3-Al2O3-SrSO4 has been studied in the range of temperatures from 800 oC to 1400 oC using X-ray diffraction, thermo gravimetric, differential thermal and scanning electron microscopy analysis. Pellets of a mixture of 3 : 3 : 1 molar ratio of reactive grade Al2O3, SrCO3 and SrSO4 respectively were prepared, by solid state sintering, the reactive powders were thoroughly mixed under high energy ball-milling, uniaxially pressed into cylindrical samples and pressureless-sintered. Additionally the densities of some samples that were heat treated for 10 h at 1200, 1300 and 1400 oC were determined by the Archimedes method. The powder mixture was analyzed by TGA and DTA from room temperature to 1200 oC. XRD patterns indicated the formation of Sr3Al2O6 and SrAl2O4 as intermediate phases that nearly at the end of the process reacted with SrSO4 to form Sr4Al6O12SO4. The formation of Sr4Al6O12SO4 was complete at 1150 oC as XRD and DTA analysis indicated. An increase in the heat treatment time promotes the formation of Sr4Al6O12SO4at lower temperatures. The Sr4Al6O12SO4 powders were composed of spherical particles of small agglomerates. Results of density measurement indicated that only 80% of the theoretical density was reached for a treatment at 1400 oC of 10 h, which indicated the difficulty to obtain a dense material.
Yeliana L. Sánchez,Manuela Yepes-Calderón,Luis Valbuena,Andrés F. Milán,María C. Trillos-Almanza,Sergio Granados,Miguel Peña,Mauricio Estrada-Castrillón,Juan C. Aristizábal,Raúl Narvez-Sanchez,Jaime G 대한내분비학회 2021 Endocrinology and metabolism Vol.36 No.5
Background: We studied whether musclin function in humans is related to glycemic control, body composition, and cardiorespiratory capacity. Methods: A cross-sectional study was performed in sedentary adults with or without metabolic syndrome (MS). Serum musclin wasmeasured by enzyme-linked immunosorbent assay. Insulin resistance (IR) was evaluated by the homeostatic model assessment(HOMA-IR). Body composition was determined by dual-energy X-ray absorptiometry and muscle composition by measuring carnosine in the thigh, a surrogate of fiber types, through proton magnetic resonance spectroscopy. Cardiorespiratory capacity was assessed through direct ergospirometry. Results: The control (n=29) and MS (n=61) groups were comparable in age (51.5±6.5 years old vs. 50.7±6.1 years old), sex(72.4% vs. 70.5% women), total lean mass (58.5%±7.4% vs. 57.3%±6.8%), and peak oxygen consumption (VO2peak) (31.0±5.8mL O2./kg.min vs. 29.2±6.3 mL O2/kg.min). Individuals with MS had higher body mass index (BMI) (30.6±4.0 kg/m2 vs. 27.4±3.6 kg/m2), HOMA-IR (3.5 [95% confidence interval, CI, 2.9 to 4.6] vs. 1.7 [95% CI, 1.1 to 2.0]), and musclin (206.7 pg/mL [95%CI, 122.7 to 387.8] vs. 111.1 pg/mL [95% CI, 63.2 to 218.5]) values than controls (P˂0.05). Musclin showed a significant relationship with HOMA-IR (β=0.23; 95% CI, 0.12 to 0.33; P˂0.01), but not with VO2peak, in multiple linear regression models adjusted forage, sex, fat mass, lean mass, and physical activity. Musclin was significantly associated with insulin, glycemia, visceral fat, and regional muscle mass, but not with BMI, VCO2peak, maximum heart rate, maximum time of work, or carnosine. Conclusion: In humans, musclin positively correlates with insulinemia, IR, and a body composition profile with high visceral adiposity and lean mass, but low body fat percentage. Musclin is not related to BMI or cardiorespiratory capacity.
Wendoline Rosiles-Alanis,Alejandro Zamilpa,Rebeca Garcı´a-Macedo,Miguel A. Zavala-Sa´nchez,Sergio Hidalgo-Figueroa,Beatriz Mora-Ramiro,Rube´n Roma´n-Ramos,Samuel E. Estrada-Soto,Julio C. Almanza-Perez 한국식품영양과학회 2022 Journal of medicinal food Vol.25 No.6
Insulin secretion and GLUT4 expression are two critical events in glucose regulation. The receptors G-protein-coupled receptor 40 (GPR40) and peroxisome proliferator-activated receptor-gamma (PPARγ) modulate these processes, and they represent potential therapeutic targets for new antidiabetic agent's design. Cucurbita ficifolia fruit is used in traditional medicine for diabetes control. Previous studies demonstrated several effects: a hypoglycemic effect mediated by an insulin secretagogue action, antihyperglycemic effect, and promoting liver glycogen storage. Anti-inflammatory and antioxidant effects were also reported. Moreover, some of its phytochemicals have been described, including d-chiro-inositol. However, to understand these effects integrally, other active principles should be investigated. The aim was to perform a chemical fractionation guided by bioassay to isolate and identify other compounds from C. ficifolia fruit that explain its hypoglycemic action as insulin secretagogue, its antihyperglycemic effect by PPARγ activation, and on liver glycogen storage. Three different preparations of C. ficifolia were tested in vivo. Ethyl acetate fraction derived from aqueous extract showed antihyperglycemic effect in an oral glucose tolerance test and was further fractioned. The insulin secretagogue action was tested in RINm5F cells. For the PPARγ activation, C2C12 myocytes were treated with the fractions, and GLUT4 mRNA expression was measured. Chemical fractionation resulted in the isolation and identification of β-sitosterol and 4-hydroxybenzoic acid (4-HBA), which increased insulin secretion, GLUT4, PPARγ, and adiponectin mRNA expression, in addition to an increase in glycogen storage. 4-HBA exhibited an antihyperglycemic effect, while β-sitosterol showed hypoglycemic effect, confirming the wide antidiabetic related results we found in our in vitro models. An in silico study revealed that 4-HBA and β-sitosterol have potential as dual agonists on PPARγ and GPR40 receptors. Both compounds should be considered in the development of new antidiabetic drug development.
Physical Properties of the Sr4Al6O12SO4 Ceramic Compound
J.A. Rodríguez-García,E. Rocha-Rangel,J. López Hernández,C.A. Hernández Bocanegra,A.L. Leal Cruz,J.M. Almanza Robles,J. Torres Torres 한양대학교 세라믹연구소 2017 Journal of Ceramic Processing Research Vol.18 No.11
The Sr4Al6O12SO4 ceramic compound was synthesized by a solid state reaction starting from stoichiometric mixtures of 3 : 3 : 1 molar ratio of reactive grade of SrCO3, Al2O3 and SrSO4, respectively. Cylindrical samples were confirmed by uniaxial pressing at 100 MPa and were heat treated at 1400 oC during 4 hrs. Subsequently, the samples were ground and re-conformed in cylindrical shape samples by uniaxial pressing at 300 MPa. The new samples were heat treated at 1400 oC during 24 hrs. This process was done in order to increase density of the samples. The Sr4Al6O12SO4 ceramic compound was characterized by the study of its physical properties such as: density, micro-hardness, thermal expansion and stability, enthalpy of formation, magnetic properties and electrical conductivity. Experimental results show that the maximum density obtained for the Sr4Al6O12SO4 ceramic compound was 2.913 grcm−3, with thermal expansion coefficient of 10.12E−06(oC−1); it also presents an enthalpy of 2.3 KJmol-1 and an excellent thermal stability at elevated temperatures in different atmospheres. In addition, the Sr4Al6O12SO4 ceramic compound is neither electrically conductive nor magnetic.
Marıa de los Angeles Fortis-Barrera,Francisco Javier Alarcon-Aguilar,Araceli Becerril-Garcıa,Jose Luis Eduardo Flores-Saenz,Julio Cesar Almanza-Perez,Mario Garcıa-Lorenzana,Roberto Carlos Lazzarini-Le 한국식품영양과학회 2020 Journal of medicinal food Vol.23 No.7
In Central and South American traditional medicine, people use Cecropia obtusifolia Bertol (Cecropiaceae) for the treatment of diabetes mellitus. However, its hypoglycemic action mechanism at pancreatic and liver level has been poorly explored. The present research aimed to establish the influence of the aqueous extract of C. obtusifolia, standardized in its content of chlorogenic acid, on insulin secretion in RINm5F cells and over the liver carbohydrates and lipids metabolism, and to determine concomitantly its hepatoprotective effect on mice with streptozotocin-induced diabetes. In RINm5F cells, concentrations 5, 50, 100, and 200 μg/mL of aqueous extract of C. obtusifolia were used to determine [Ca2+]i and insulin secretion. In an acute study, the extract was administered at doses of 500 mg/kg. In another test (subacute), the extract was daily administrated to diabetic mice (200 mg/kg/day) for 30 days. Blood glucose levels and other biochemical parameters were determined, and a liver histological analysis was performed. In RINm5F cells, C. obtusifolia increased [Ca2+]i and insulin secretion, whereas in diabetic mice exhibited acute and subacute hypoglycemic effects. Daily administration of C. obtusifolia to diabetic mice also increased liver glycogen storage and glycogen synthase levels, without apparent changes in gluconeogenesis. Besides, it increased peroxisome proliferator-activated receptor-α (PPAR-α) and long-chain-fatty-acid-CoA ligase 1 (ACSL-1) expression and reduced triglycerides, transaminases (alanine aminotransferase and aspartate aminotransferase), and collagen fibers, modifying anti-inflammatory (adiponectin and interleukin-10) and inflammatory (tumor necrosis factor-α) cytokines in serum. Therefore, the hypoglycemic effect of C. obtusifolia implicates a dual action, promoting insulin secretion, liver glycogen accumulation, and hepatoprotection by decreasing collagen fibers and inflammatory markers, whereas it improves lipid metabolism, due in part to PPAR-α.