Positive inotropic activity induced by a dehydroisoandrosterone derivative in isolated rat heart model

L. Figueroa-Valverde,F. Dı´az-Cedillo,E. Garcı´a-Cervera,E. Pool Go´mez,M. Lo´pez-Ramos,M. Rosas-Nexticapa,R. Martinez-Camacho 대한약학회 2013 Archives of Pharmacal Research Vol.36 No.10

Experimental studies indicate that some steroidderivatives have inotropic activity; nevertheless, there isscarce information about the effects of the dehydroisoandrosteroneand its derivatives at cardiovascular level. Inaddition, to date the cellular site and mechanism of actionof dehydroisoandrosterone at cardiovascular level is veryconfusing. In order, to clarify those phenomena in this study,a dehydroisoandrosterone derivative was synthesized withthe objective of to evaluate its activity on perfusion pressureand coronary resistance and compare this phenomenon withthe effect exerted by dehydroisoandrosterone. The Langendorfftechnique was used to measure changes on perfusionpressure and coronary resistance in an isolated rat heartmodel in absence or presence of dehydroisoandrosterone andits derivative. Additionally, to characterize the molecularmechanism involved in the inotropic activity induced bydehydroisoandrosterone derivative was evaluated by measuringleft ventricular pressure in absence or presence offollowing compounds; flutamide, prazosin, metoprolol andnifedipine. The results showed that dehydroisoandrosteronederivative significantly increased the perfusion pressure andcoronary resistance in comparison with the control conditionsand dehydroisoandrosterone. Additionally, other dataindicate that dehydroisoandrosterone derivative increase leftventricular pressure in a dose-dependent manner [1 9 10-9–1 9 10-4 mmol]; nevertheless, this phenomenon was significantlyinhibited by nifedipine at a dose of 1 9 10-6mmol. In conclusion, these data suggest that dehydroisoandrosteronederivative induces positive inotropic activitythrough of activation the L-type calcium channel.

Roundtable on Teri L. Caraway's "De-Thaksinizing Thailand: The Limits of Institutional Design"

Erik Martinez Kuhonta,Allen Hicken,Joel Sawat Selway,Teri L. Caraway 동아시아연구원 2020 Journal of East Asian Studies Vol.20 No.3

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Plant responses to nano and micro structured carbon allotropes: Water imbibition by maize seeds upon exposure to multiwalled carbon nanotubes and activated carbon

Dasgupta-Schubert, N.,Tiwari, D.K.,Francis, E. Reyes,Martinez Torres, P.,Villasenor Cendejas, L.M.,Lara Romero, J.,Villasenor Mora, C. Techno-Press 2017 Advances in nano research Vol.5 No.3

Multiwalled carbon-nanotubes (MWCNT) and micro-structured carbon, such as biochar or activated carbon (AC), have been seen to significantly increase the growth indices of certain plant species such as maize (Zea mays L.). Seed imbibition is the stage where environmental factors that affect water transport across the seed coat barrier, make a large impact. This work explores the effect on water imbibition by maize seeds when the aqueous environment surrounding the seed is diluted by small concentrations (10 and 20 mg/l) of pristine MWCNT (p-MWCNT), carboxylate functionalized MWCNT (COO-MWCNT) and AC. The degree of sensitivity of the process to (i) large structural changes is seen by utilizing the nano (the MWCNT) and the micro (the AC) allotropic forms of carbon; (ii) to small changes in the purity and morphology of the p-MWCNT by utilizing 95% pure and 99% pure p-MWCNTs of slightly differing morphologies; and (iii) to MWCNT functionalization by using highly pure (97%) COO-MWCNT. Water imbibition was monitored over a 15 hour period by Near Infrared Thermography (NIRT) and also by seed weighing. Seed surface topography was seen by SEM imaging. Analysis of the NIRT images suggests rapid seed surface topological changes with the quantity of water imbibed. While further work is necessary to arrive at a conclusive answer, this work shows that the imbibition phase of the maize seed is sensitive to the presence of MWCNT even to small differences in the purity of the p-MWCNT and to small differences in the physicochemical properties of the medium caused by the hydrophilic COO-MWCNT.

Potential Control of Foodborne Pathogenic Bacteria by Pediococcus pentosaceus and Lactobacillus graminis Isolated from Fresh Vegetables

( C. J. Gonzalez-perez ),( I. Vargas-arispuro ),( E. Aispuro-hernandez ),( C. L. Aguilar-gil ),( Y. E. Aguirre-guzman ),( A. Castillo ),( A. Hernandez-mendoza ),( J. F. Ayala-zavala ),( M. A. Martinez 한국미생물생명공학회(구 한국산업미생물학회) 2019 한국미생물·생명공학회지 Vol.47 No.2

The consumption of fresh vegetables has been related to recurrent outbreaks of foodborne diseases (FBD) worldwide. Therefore, the development of effective alternative technologies is necessary to improve the safety of these products. This study aimed to isolate and identify epiphytic lactic acid bacteria (LAB) from fresh fruits and leafy vegetables and characterize their antagonistic capacity due to their ability to produce bacteriocins or antibacterial compounds. For this, 92 LAB isolates from fruits and leafy vegetables were screened for antagonistic activity. Two strains with the highest and broadest antagonistic activities were selected for further characterization; one from cantaloupe melon (strain CM175) and one from cilantro leaves (strain C15). The cell-free supernatants (CFS) of CM175 and C15 were found to exhibit antagonistic activity against FBD-causing pathogens. The CM175 and C15 strains were identified as Pediococcus pentosaceus and Lactobacillus graminis, respectively. Notably, the P. pentosaceus CM175 CFS stopped the growth of Salmonella Typhimurium, Salmonella Saintpaul, Staphylococcus aureus, and Listeria monocytogenes, and delayed Escherichia coli O157:H7 growth. Moreover, L. graminis C15 CFS delayed the growth of all indicator pathogens, but did not completely stop it. Organic acids and bacteriocin-like molecules were determined to be possibly exerting the observed antagonistic activity of the identified LAB strains. Thus, application of the antagonistic compounds produced by Pediococcus pentosaceus and Lactobacillus graminis could be a novel and ecological strategy in developing antimicrobial biopreservatives for the food industry and mitigating FBD by reducing the biological contamination in fruit and vegetable orchards, mainly via their potential in controlling both gram-negative and gram-positive pathogenic bacteria.

Potential Control of Foodborne Pathogenic Bacteria by Pediococcus pentosaceus and Lactobacillus graminis Isolated from Fresh Vegetables

Gonzalez-Perez, C.J.,Vargas-Arispuro, I.,Aispuro-Hernandez, E.,Aguilar-Gil, C.L.,Aguirre-Guzman, Y.E.,Castillo, A.,Hernandez-Mendoza, A.,Ayala-Zavala, J.F.,Martinez-Tellez, M.A. The Korean Society for Microbiology and Biotechnol 2019 한국미생물·생명공학회지 Vol.47 No.2

The consumption of fresh vegetables has been related to recurrent outbreaks of foodborne diseases (FBD) worldwide. Therefore, the development of effective alternative technologies is necessary to improve the safety of these products. This study aimed to isolate and identify epiphytic lactic acid bacteria (LAB) from fresh fruits and leafy vegetables and characterize their antagonistic capacity due to their ability to produce bacteriocins or antibacterial compounds. For this, 92 LAB isolates from fruits and leafy vegetables were screened for antagonistic activity. Two strains with the highest and broadest antagonistic activities were selected for further characterization; one from cantaloupe melon (strain CM175) and one from cilantro leaves (strain C15). The cell-free supernatants (CFS) of CM175 and C15 were found to exhibit antagonistic activity against FBD-causing pathogens. The CM175 and C15 strains were identified as Pediococcus pentosaceus and Lactobacillus graminis, respectively. Notably, the P. pentosaceus CM175 CFS stopped the growth of Salmonella Typhimurium, Salmonella Saintpaul, Staphylococcus aureus, and Listeria monocytogenes, and delayed Escherichia coli O157:H7 growth. Moreover, L. graminis C15 CFS delayed the growth of all indicator pathogens, but did not completely stop it. Organic acids and bacteriocin-like molecules were determined to be possibly exerting the observed antagonistic activity of the identified LAB strains. Thus, application of the antagonistic compounds produced by Pediococcus pentosaceus and Lactobacillus graminis could be a novel and ecological strategy in developing antimicrobial biopreservatives for the food industry and mitigating FBD by reducing the biological contamination in fruit and vegetable orchards, mainly via their potential in controlling both gram-negative and gram-positive pathogenic bacteria.

A convex version of multivariate adaptive regression splines

Martinez, D.L.,Shih, D.T.,Chen, V.C.P.,Kim, S.B. North-Holland Pub. Co ; Elsevier Science Ltd 2015 Computational statistics & data analysis Vol.81 No.-

Multivariate adaptive regression splines (MARS) provide a flexible statistical modeling method that employs forward and backward search algorithms to identify the combination of basis functions that best fits the data and simultaneously conduct variable selection. In optimization, MARS has been used successfully to estimate the unknown functions in stochastic dynamic programming (SDP), stochastic programming, and a Markov decision process, and MARS could be potentially useful in many real world optimization problems where objective (or other) functions need to be estimated from data, such as in surrogate optimization. Many optimization methods depend on convexity, but a non-convex MARS approximation is inherently possible because interaction terms are products of univariate terms. In this paper a convex MARS modeling algorithm is described. In order to ensure MARS convexity, two major modifications are made: (1) coefficients are constrained, such that pairs of basis functions are guaranteed to jointly form convex functions and (2) the form of interaction terms is altered to eliminate the inherent non-convexity. Finally, MARS convexity can be achieved by the fact that the sum of convex functions is convex. Convex-MARS is applied to inventory forecasting SDP problems with four and nine dimensions and to an air quality ground-level ozone problem.

Characterization of recycled polycarbonate from electronic waste and its use in hydraulic concrete: Improvement of compressive performance

Colina-Martinez, Ana L. De la,Martinez-Barrera, Gonzalo,Barrera-Diaz, Carlos E.,Avila-Cordoba, Liliana I.,Urena-Nunez, Fernando Techno-Press 2017 Advances in concrete construction Vol.5 No.6

Transparency, excellent toughness, thermal stability and a very good dimensional stability make Polycarbonate (PC) one of the most widely used engineering thermoplastics. Polycarbonate market include electronics, automotive, construction, optical media and packaging. One alternative for reducing the environmental pollution caused by polycarbonate from electronic waste (e-waste), is to use it in cement concretes. In this work, physical and chemical characterization of recycled polycarbonate from electronic waste was made, through the analysis by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and scanning electron microscope (SEM). Then cement concrete was made with Portland cement, sand, gravel, water, and this recycled polycarbonate. Specimens without polycarbonate were produced for comparison purposes. The effect of the particle sizes and concentrations of recycled polycarbonate within the concrete, on the compressive strength and density was studied. Results show that compressive strength values and equilibrium density of concrete depend on the polycarbonate particle sizes and its concentrations; particularly the highest compressive strength values were 20% higher than that for concrete without polycarbonate particles. Moreover, morphological, structural and crystallinity characteristics of recycled polycarbonate, are suitable for to be mixed into concrete.

Energy optimization of a Sulfur-Iodine thermochemical nuclear hydrogen production cycle

Juarez-Martinez, L.C.,Espinosa-Paredes, G.,Vazquez-Rodriguez, A.,Romero-Paredes, H. Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.6

The use of nuclear reactors is a large studied possible solution for thermochemical water splitting cycles. Nevertheless, there are several problems that have to be solved. One of them is to increase the efficiency of the cycles. Hence, in this paper, a thermal energy optimization of a Sulfur-Iodine nuclear hydrogen production cycle was performed by means a heuristic method with the aim of minimizing the energy targets of the heat exchanger network at different minimum temperature differences. With this method, four different heat exchanger networks are proposed. A reduction of the energy requirements for cooling ranges between 58.9-59.8% and 52.6-53.3% heating, compared to the reference design with no heat exchanger network. With this reduction, the thermal efficiency of the cycle increased in about 10% in average compared to the reference efficiency. This improves the use of thermal energy of the cycle.

Sustainable Development of Palm Oil: Synthesis and Electrochemical Performance of Corrosion Inhibitors

Porcayo-Calderon, J.,Rivera-Munoz, E.M.,Peza-Ledesma, C.,Casales-Diaz, M.,de la Escalera, L.M. Martinez,Canto, J.,Martinez-Gomez, L. The Korean Electrochemical Society 2017 Journal of electrochemical science and technology Vol.8 No.2

Palm oil production is among the highest worldwide, and it has been mainly used in the food industry and other commodities. Currently, a lot of palm oil production has been destined for the synthesis of biodiesel; however, its use in applications other than the food industry has been questioned. Thereby for a sustainable development, in this paper the use of palm oil of low quality for corrosion inhibitors synthesis is proposed. The performance of the synthesized inhibitors was evaluated by using electrochemical techniques such as open circuit potential measurements, linear polarization resistance and electrochemical impedance spectroscopy. The results indicate that the fatty amides from palm oil are excellent corrosion inhibitors with protection efficiencies greater than 98%. Fatty amides molecules act as cathodic inhibitors decreasing the anodic dissolution of iron. When fatty amides are added, a rapid decrease in the corrosion rate occurs due to the rapid formation of a molecular film onto carbon steel surface. During the adsorption process of the inhibitor a self-organization of the hydrocarbon chains takes place forming a tightly packed hydrophobic film. These results demonstrate that the use of palm oil for the production of green inhibitors promises to be an excellent alternative for a sustainable use of the palm oil production.

Shear Zone Evolution of Granular Soils in Contact with Conventional and Textured CPT Friction Sleeves

G. L. Hebeler,A. Martinez,J. D. Frost 대한토목학회 2016 KSCE Journal of Civil Engineering Vol.20 No.4

Interfaces, and the shearing of soil against them, play a crucial role in geotechnical engineering. As such, understanding the fundamental mechanisms of interface behavior, such as the size, shape, and extent of soil shear zones against geomaterial surfaces can lead to better understanding and design of geotechnical systems and testing methods. The current study presents a series of laboratory studies aimed at spatially quantifying shear zones created through soil – geomaterial interface shearing including mobilized interface strengths with a focus on CPT friction sleeve behavior. Parametric investigations of particle shape and size effects were carried out over a range of counterface surface roughness values. The results show that conventional “smooth” CPT friction sleeves induce solely particle sliding in coarse grained soils, while non-clogging textured friction sleeves can create a combination of particle shearing and sliding that can allow for direct interface measurements in-situ. By varying the amount of texture on an interface, the extent of particle shearing can be controlled, allowing for improved understanding and treatment of interfaces in geotechnical testing and design.