Zeolite Synthesis in FluorideMedia: Structure Directiontoward ITW by Small Methylimidazolium Cations

Rojas, Alex,Martí,nez-Morales, Evangelina,Zicovich-Wilson, Claudio M.,Camblor, Miguel A. American Chemical Society 2012 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.134 No.4

<P>Pure silica ITW zeolite can be synthesized using 1,2,3-trimethylimidazoliumand 1,3-dimethylimidazolium cations and fluoride anions as structure-directingagents (SDAs). Similarly to the previously reported 1,3,4-trimethylimidazolium,the dimethyl cation can also produce the zeolite TON, but this higherframework density phase finally transforms <I>in situ</I> into ITW. The structures of the as-made and calcined phases preparedwith the new cations show a unit cell doubling along <I>z</I>, and the refined structures are reported. Periodic Density FunctionalTheory calculations provide the energies of the six SDA-ITW and SDA-TONzeolites, and their relative stabilities fully agree with the experimentalobservations. Structure-direction in this system is discussed fromexperimental and theoretical results that give strong support to theidea that strained silica frameworks are made possible in fluoridemedia by decreasing the covalent character of the Si–O bond.This decreased covalency is enhanced with the 1,2,3-trimethyl isomer,which is shown to be the strongest SDA for ITW and, at the same time,is the more hydrophilic of the three SDAs tested. Our observationswith the three SDAs agree with the so-called Villaescusa’srule, i.e., the low framework density phase is favored at higher concentrations,but at the same time question the supersaturation hypothesis thathas been proposed to explain this rule, since here the low-densityphase is the most stable one.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jacsat/2012/jacsat.2012.134.issue-4/ja209832y/production/images/medium/ja-2011-09832y_0002.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja209832y'>ACS Electronic Supporting Info</A></P>

Glycolate Oxidase Modulates Reactive Oxygen Species-Mediated Signal Transduction during Nonhost Resistance in Nicotiana benthamiana and Arabidopsis

Rojas, C.M.,Senthil-Kumar, M.,Wang, K.,Ryu, C.-M.,Kaundal, A.,Mysore, K.S. AMERICAN SOCIETY OF PLANT BIOLOGISTS 2012 The Plant cell Vol.24 No.1

스페인 정치선전에 언어학전 연구 (1977-1986)

Rojas, Eva Gomez,Eva Gomez Rojas 한국외국어대학교 1988 한국외국어대학교 논문집 Vol.21 No.1

Design of isolated footings of circular form using a new model

Rojas, Arnulfo Luevanos Techno-Press 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.52 No.4

This paper presents the design of reinforced concrete circular footings subjected to axial load and bending in two directions using a new model. The new model considers the soil real pressure acting on contact surface of the circular footings and these are different, with a linear variation in the contact area, these pressures are presented in terms of the axial load, moments around the axis "X" and the axis "Y". The classical model takes into account only the maximum pressure of the soil for design of footings and it is considered uniform at all points of contact area. Also, a comparison is presented in terms of the materials used (steel and concrete) between the two models shown in table, being greater the classical model with respect the new model. Therefore, the new model is the most appropriate, since it is more economic and also is adjusted to real conditions.

Acute and Repeated 28-Day Oral Dose Toxicity Studies of Thymus vulgaris L. Essential Oil in Rats

Rojas-Armas, Juan,Arroyo-Acevedo, Jorge,Ortiz-Sanchez, Manuel,Palomino-Pacheco, Miriam,Castro-Luna, Americo,Ramos-Cevallos, Norma,Justil-Guerrero, Hugo,Hilario-Vargas, Julio,Herrera-Calderon, Oscar Korean Society of ToxicologyKorea Environmental Mu 2019 Toxicological Research Vol.35 No.3

Thymus vulgaris L. is widely used as an ingredient in cooking and in herbal medicine. However, there is little information about its toxicity. The present study was performed to evaluate the acute and repeated 28-day oral dose toxicity of thyme essential oil in rats. For the acute toxicity test, two groups of three rats were used. The rats received a single dose of essential oil: 300 or 2,000 mg/kg of body weight (bw). The rats were observed individually during the first four hours, and then daily until day 14. For the toxicity test with repeated doses, four groups of 10 rats were used. Doses of 100, 250, and 500 mg/kg/day were tested for 28 days. At the end of the experiment, blood was collected and the animals were sacrificed. Histopathological examination showed that in the lungs of rats given the 2,000 mg/kg bw dose, polymorph nuclear infiltrates, hemosiderin macrophages, and interstitial space thickening were present. In the repeated dose study, all rats survived the 28-day treatment period and apparently showed no signs of toxicity. The hematological and biochemical parameters were not altered. The histopathological study of the organs showed severe changes in the lung, with the dose of 500 mg/kg/day; in the other organs, no alterations were observed or the changes were slight. The body weight was only altered in male rats given the 500 mg/kg dose. The relative weight of the organs did not show any significant changes. Our studies revealed that the essential oil of Thymus vulgaris has moderate oral toxicity according to the results of the acute test, whereas the results of the 28-day oral toxicity test suggest that the no-observed-adverse effect level (NOAEL) is greater than 250 mg/kg/day.

Modifying Polydiacetylene Vesicle Compositions to Reduce Non-Specific Interactions

Gumaro Rojas,Priyanka Shiveshwarkar,임부택,Anura Shrestha,Izele Abure,Anthony Nelson,Justyn Jaworski 한국고분자학회 2021 Macromolecular Research Vol.29 No.7

Polydiacetylene (PDA) vesicles provide useful stimuli-responsive behavior as well as by the modular structure afford a means for the design of sensing and delivery systems with tunable target specificity. To reduce inherent non-specific interaction with either anionic or cationic formulations of polydiacetylene vesicles, we explored the use of various lengths of poly(ethylene glycol) (PEG) amphiphiles for integration and polymerization within PDA vesicles. Our results established that as little as 1% of polyethylene glycol amphiphile integration into anionic vesicles was sufficient to significantly reduce non-specific association with mammalian cells. Similarly integrating a low percent of PEG amphiphile content within cationic vesicles could also significantly reduce non-specific cell association, and moreover reduced cytotoxicity. These results may be prove useful in augmenting PDA vesicles formulations for reduced non-specific interaction which is of particularly interest to enhancing selectivity in vesicles designed with integrated targeting moieties for sensing and drug delivery applications.

A new model for T-shaped combined footings part I: Optimal dimensioning

Luevanos-Rojas, Arnulfo,Lopez-Chavarria, Sandra,Medina-Elizondo, Manuel Techno-Press 2018 Geomechanics & engineering Vol.14 No.1

The foundations are classified into shallow and deep, which have important differences: in terms of geometry, the behavior of the soil, its structural functionality, and its constructive systems. The shallow foundations may be of various types according to their function; isolated footings, combined footings, strip footings, and slabs foundation. The isolated footings are of the type rectangular, square and circular. The combined footing may be rectangular, trapezoidal or T-shaped in plan. This paper presents a new model for T-shaped combined footings to obtain the most economical contact surface on the soil (optimal dimensioning) to support an axial load and moment in two directions to each column. The new model considers the soil real pressure, i.e., the pressure varies linearly. The classical model uses the technique of test and error, i.e., a dimension is proposed, and subsequently, the equation of the biaxial bending is used to obtain the stresses acting on each vertex of the T-shaped combined footing, which must meet the conditions following: The minimum stress should be equal or greater than zero, and maximum stress must be equal or less than the allowable capacity that can withstand the soil. To illustrate the validity of the new model, numerical examples are presented to obtain the minimum area of the contact surface on the soil for T-shaped combined footings subjected to an axial load and moments in two directions applied to each column.

A comparative study for design of boundary combined footings of trapezoidal and rectangular forms using new models

Luevanos-Rojas, Arnulfo,Barquero-Cabrero, Jose Daniel,Lopez-Chavarria, Sandra,Medina-Elizondo, Manuel Techno-Press 2017 Coupled systems mechanics Vol.6 No.4

This paper shows a comparative study for design of reinforced concrete boundary combined footings of trapezoidal and rectangular forms supporting two columns and each column transmits an axial load and a moment around of the axis X (transverse axis of the footing) and other moment around of the axis Y (longitudinal axis of the footing) to foundation to obtain the most economical combined footing. The real soil pressure acting on the contact surface of the footings is assumed as a linear variation. Methodology used to obtain the dimensions of the footings for the two models consider that the axis X of the footing is located in the same position of the resultant, i.e., the dimensions is obtained from the position of the resultant. The main part of this research is to present the differences between the two models. Results show that the trapezoidal combined footing is more economical compared to the rectangular combined footing. Therefore, the new model for the design of trapezoidal combined footings should be used, and complies with real conditions.

Economic Complexity, Economic Growth, and CO2 Emissions: A Panel Data Analysis

Laverde-Rojas Henry,Correa Juan C. 한국국제경제학회 2021 International Economic Journal Vol.35 No.4

Reducing global warming effects without jeopardizing economic prosperity demands the analysis of the link between these factors. Environmental degradation and economic growth are thought to be related in a non-linear manner, following an inverted-U pattern called the ‘Environmental Kuznets Curve’ (EKC). Despite the many studies seeking empirical support for this relationship, the literature does not provide conclusive findings. By presenting the Economic Complexity Index (ECI) as an explanatory variable, this paper aims at providing a comprehensive analysis of EKC from 86 countries with different development levels, covering the period between 1971 and 2014. Different statistical estimation techniques were used, including an Adaptive Neuro-Fuzzy Inference System (ANFIS) model, dynamic panel data techniques, and the Sasabuchi–Lind–Mehlum (SLM) test. The results show no clear evidence supporting the idea of EKC, neither for production volumes nor for production sophistication, as captured by ECI. Nonetheless, when ECI increases, pollution levels drop monotonously only for developed countries.

Panax ginseng – derived fraction BIOGF1K reduces atopic dermatitis responses via suppression of mitogen-activated protein kinase signaling pathway

Laura Rojas Lorz,Donghyun Kim,Mi-Yeon Kim,Jae Youl Cho 고려인삼학회 2020 Journal of Ginseng Research Vol.44 No.3

Background: BIOGF1K, a fraction of Panax ginseng, has desirable antimelanogenic, anti-inflammatory, andantiphotoaging properties that could be useful for treating skin conditions. Because its potential positiveeffects on allergic reactions in skin have not yet been described in detail, this study’s main objective wasto determine its efficacy in the treatment of atopic dermatitis (AD). Methods: High-performance liquid chromatography was used to verify the compounds in BIOGF1K, andwe used the (3-4-5-dimethylthiazol-2-yl)-2-5-diphenyltetrazolium bromide method to determine itscytotoxicity in RBL-2H3 and HMC-1 cell lines. RBL-2H3 cells were induced using both antieDNP-IgE/DNP-BSA and calcium ionophore (A2187) treatments, whereas HMC-1 cells were induced using A2187alone. To measure mast cell degranulation, we performed histamine (enzyme-linked immunosorbentassay) and b-hexosaminidase assays. To quantify interleukin (IL)-4, IL-5, and IL-13 levels in RBL-2H3 cells,we performed quantitative polymerase chain reaction (PCR); to quantify expression levels of IL-4 and IL-13 in HMC-1 cells, we used semiquantitative reverse transcription polymerase chain reaction (RT-PCR). Finally, we detected the total and phosphorylated forms of extracellular signal-regulated kinase, p-38,and c-Jun N-terminal kinase proteins by immunoblotting. Results: BIOGF1K decreased the AD response by reducing both histamine and b-hexosaminidase releaseas well as reducing the secretion levels of IL-4, IL-5, and IL-13 in RBL-2H3 cells and IL-4 and IL-13 inHMC-1 cells. In addition, BIOGF1K decreased MAPK pathway activation in RBL-2H3 and HMC-1 cells. Conclusions: BIOGF1K attenuated the AD response, hence supporting its use as a promising and naturalapproach for treating AD.