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Molecular Characterization of Polypropylene Heterophasic Copolymers by Fractionation Techniques
Rafael A. García,Baudilio Coto,María-Teresa Expósito,Inmaculada Suarez,Almudena Fernández-Fernández,Susana Caveda 한국고분자학회 2011 Macromolecular Research Vol.19 No.8
Molecular microstructure, thermal properties and morphology of three polypropylene heterophasic copolymers (PHC) with similar comonomer content were characterized by gel permeation chromatography (GPC),differential scanning calorimetry (DSC), analytical and preparative temperature rising elution fractionation (TREF),scanning electron microscopy (SEM), and carbon nuclear magnetic resonance spectroscopy (13C NMR). These results indicate that there are no differences in solution and thermal properties between unfractionated copolymers. Nevertheless, a physical fractionation by crystallization of these copolymers was developed to carry out a detailed study. Four fractions at different temperatures were collected. The results showed that the PHC’s copolymers are composed by polypropylene, ethylene-propylene rubber (EPR) and, crystallisable sequences with different propylene and/or ethylene comonomers distribution. Despite the similar thermo-chemical properties shown by the raw PHC’s copolymers, the characterization of fractions displayed significant differences between them. These results suggest that the fractionation by crystallization allows the different components in which the PHC’s copolymers are based to be distinguished clearly, and obtain a more comprehensive sense of the molecular structure characterization.
Red alga <i>Grateloupia imbricata</i> (Halymeniaceae), a species introduced into the Canary Islands
Garcí,a-Jimé,nez, Pilar,Geraldino, Paul John L.,Boo, Sung Ming,Robaina, Rafael R. Blackwell Publishing Asia 2008 Phycological research Vol.56 No.3
<P>SUMMARY</P><P>Specimens of <I>Grateloupia</I> from Gran Canaria in the Canary Islands were used to molecularly ascertain which of the species has been used in physiological and bio-technological experiments. The <I>rbc</I>L sequence analysis revealed that four out of five analyzed specimens (i.e. those commonly collected for physiological research) formed a monophyletic clade with <I>G. imbricata</I> from Korea, Japan, and China, and were quite different from any other species of the genus. Another sample, which was associated with cage nets used for fish aquaculture, was grouped with <I>G. lanceolata</I> from Japan, though it appears too early as yet to identify it as such. This is, thus, proof of a new introduction of a marine macroalga, since <I>G. imbricata</I> is an Asian species, native to Japan and Korea, in the Canary Islands. The role of international shipping in the introduction of the species is discussed.</P>
Fluorescence Guided Surgery with 5-Aminolevulinic Acid for Resection of Spinal Cord Ependymomas
Rafael García Moreno,Luis Miguel Bernal García,Hyaissa Ippolito Bastidas,Carlos Andrés Mondragón Tirado,Aurora Moreno Flores,Juan Pablo Sosa Cabezas,José Manuel Cabezudo Artero 대한척추외과학회 2019 Asian Spine Journal Vol.13 No.1
Study Design: A retrospective study. Purpose: We report our experience with 5-aminolevulinic acid (5-ALA)–assisted resection of spinal cord ependymomas in adults. Overview of Literature: Ependymoma is the most frequent primary spinal cord tumor in adults. Surgery is the treatment of choice in most cases. However, while complete resection is achieved in approximately 80% of cases, clinical improvement is achieved in 15% only. Five-ALA fluorescence–guided surgery seems to be useful for this tumor type. Methods: We studied 14 patients undergoing 5-ALA fluorescence-guided surgery for spinal cord ependymomas in our service. The modified McCormick classification was used to determine clinical status and the degree of resection was assessed with magnetic resonance imaging. Results: Of the 14 patients, the tumor showed an intense emission of fluorescence in 12 and the fluorescence was weak and nonuniform in two. Complete resection was achieved in 11 cases. According to the McCormick classification, 10 patients improved, two remained the same, and two deteriorated. Conclusions: Our results confirm that 5-ALA fluorescence-guided resection is useful in spinal cord ependymoma resection. Although the rate of complete resections is similar to that in published series without 5-ALA, clinical results are better when using 5-ALA with a lower percentage of clinical deterioration.
Rafael Eduardo Hernández-Guisao,Aranda-Barradas Juan Silvestre,Badillo-Corona Agustín,García-Peña Elvia Inés,Salgado-Manjarrez Edgar 한국생물공학회 2022 Biotechnology and Bioprocess Engineering Vol.27 No.5
Stoichiometric analysis is a crucial step in biochemical processes because it allows us to find the proportions in which the substrates and products react. A system of algebraic equation is obtained from an elemental balance of the participating substances and determined, overdetermined or underdetermined systems can result depending on the number of substances and elements. Underdetermined systems are the most common ones as there are, generally, more substances than elemental balances. However, such systems have been poorly studied and a straightforward way to establish the solution space has not yet been reported. In this work a novel approach for finding all the possible solutions to such underdetermined systems is reported for the first time. The solutions space is expressed as a set of vectors which are here referred as extreme stoichiometries. To illustrate the general applicability and some uses of the proposed approach, three different fermentation systems are analyzed: growth of Chlamydomonas reinhardtii, a mixed culture for hydrogen production, and the growth of Saccharomyces cerevisiae. It is shown how the full stoichiometric spaces can be calculated for heterotrophy, autotrophy, mixotrophy, growth of mixed cultures in mixed substrates and how the experimental results should be contained in such spaces, what permits a consistency analysis. With the proposed method, it is now possible to estimate the maximum yields for any given microbial growth reaction and to assess the congruence of experimental data, even when the system is underdetermined.
Alejandre-Castañeda Viridiana,Patiño-Medina J. Alberto,Valle-Maldonado Marco I.,García Alexis,Ortiz-Alvarado Rafael,Ruíz-Herrera León F.,Castro-Cerritos Karla Viridiana,Ramírez-Emiliano Joel,Ramírez-D 한국미생물학회 2023 The journal of microbiology Vol.61 No.12
Mucormycosis is a lethal and difficult-to-treat fungal infection caused by fungi of the order Mucorales. Mucor lusitanicus, a member of Mucorales, is commonly used as a model to understand disease pathogenesis. However, transcriptional control of hyphal growth and virulence in Mucorales is poorly understood. This study aimed to investigate the role of Tec proteins, which belong to the TEA/ATTS transcription factor family, in the hyphal development and virulence of M. lusitanicus. Unlike in the genome of Ascomycetes and Basidiomycetes, which have a single Tec homologue, in the genome of Mucorales, two Tec homologues, Tec1 and Tec2, were found, except in that of Phycomyces blakesleeanus, with only one Tec homologue. tec1 and tec2 overexpression in M. lusitanicus increased mycelial growth, mitochondrial content and activity, expression of the rhizoferrin synthetase-encoding gene rfs, and virulence in nematodes and wax moth larvae but decreased cAMP levels and protein kinase A (PKA) activity. Furthermore, tec1- and tec2-overexpressing strains required adequate mitochondrial metabolism to promote the virulent phenotype. The heterotrimeric G beta subunit 1-encoding gene deletant strain (Δgpb1) increased cAMP-PKA activity, downregulation of both tec genes, decreased both virulence and hyphal development, but tec1 and tec2 overexpression restored these defects. Overexpression of allele-mutated variants of Tec1(S332A) and Tec2(S168A) in the putative phosphorylation sites for PKA increased both virulence and hyphal growth of Δgpb1. These findings suggest that Tec homologues promote mycelial development and virulence by enhancing mitochondrial metabolism and rhizoferrin accumulation, providing new information for the rational control of the virulent phenotype of M. lusitanicus.
Ana Sanchis,María Adelaida García-Gimeno,Antonio José Cañada-Martínez,María Dolores Sequedo,José María Millán,Pascual Sanz,Rafael P. Vázquez-Manrique 생화학분자생물학회 2019 Experimental and molecular medicine Vol.51 No.-
Huntington disease is a neurodegenerative condition for which there is no cure to date. Activation of AMP-activated protein kinase has previously been shown to be beneficial in in vitro and in vivo models of Huntington’s disease. Moreover, a recent cross-sectional study demonstrated that treatment with metformin, a well-known activator of this enzyme, is associated with better cognitive scores in patients with this disease. We performed a preclinical study using metformin to treat phenotypes of the zQ175 mouse model of Huntington disease. We evaluated behavior (motor and neuropsychiatric function) and molecular phenotypes (aggregation of mutant huntingtin, levels of brain-derived neurotrophic factor, neuronal inflammation, etc.). We also used two models of polyglutamine toxicity in Caenorhabditis elegans to further explore potential mechanisms of metformin action. Our results provide strong evidence that metformin alleviates motor and neuropsychiatric phenotypes in zQ175 mice. Moreover, metformin intake reduces the number of nuclear aggregates of mutant huntingtin in the striatum. The expression of brain-derived neurotrophic factor, which is reduced in mutant animals, is partially restored in metformin-treated mice, and glial activation in mutant mice is reduced in metformin-treated animals. In addition, using worm models of polyglutamine toxicity, we demonstrate that metformin reduces polyglutamine aggregates and restores neuronal function through mechanisms involving AMP-activated protein kinase and lysosomal function. Our data indicate that metformin alleviates the progression of the disease and further supports AMP-activated protein kinase as a druggable target against Huntington’s disease.
Heriberto Granados‑Becerra,Víctor H. López‑Morelos,Alberto Ruiz,Rafael García‑Hernández,Francisco F. Curiel‑López,Martin R. Barajas‑Alvarez 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.6
The Ramberg–Osgood equation was applied to model the stress–strain behavior of heat-treated and welded specimens ofInconel 600 up to 0.2 and 0.175 mm/mm of strain, respectively. As-received and aged plates of Inconel 600 were gas metalarc welded to simulate repair of a component in operation. Dog bone shape specimens were tensile tested at a cross headspeed of 0.005 s−1 and the deformation was measured with an extensometer with a gage length of 20 mm. Microstructuralobservations were made in the optical and scanning electron microscope. Fitting the experimental data in the plastic regionof stress–strain curves to a novel three slopes Ramberg–Osgood model enabled estimation of the hardening coefficient, n. The value of n varied from 0.07 to 0.3 depending on the metallurgical condition of the specimen. A notorious increase wasobserved in the value of n for samples heat-treated beyond 25 h and in as-welded samples. The results of this work showeda very good correlation between the model and the experimental curves.
Recent introduction of Gracilaria parvispora (Gracilariales, Rhodophyta) in Baja California, Mexico
Garcí,a-Rodrí,guez, Luis Daniel,Riosmena-Rodrí,guez, Rafael,Kim, Su Yeon,Ló,pez-Meyer, Melina,Orduñ,a-Rojas, Javier,Ló,pez-Vivas, Juan Manuel,Boo, Sung Min Walter de Gruyter GmbH 2013 Botanica marina Vol.56 No.2
José Aurelio Sosa,José Ramón Laines,David Salvador García,Rafael Hernández,Mark Zappi,Alejandra E. Espinosa de los Monteros 대한환경공학회 2023 Environmental Engineering Research Vol.28 No.3
The energy growing demand and the international environmental policies contribute to the use of renewable energy sources. Among these sources, biogas has acquired great relevance due to its energetic similarity to fuels such as liquefied petroleum gas (LPG) and natural gas (NG). However, biogas needs to be upgraded by removing CO2 and trace gases to obtain biomethane (>85% CH4). This review identifies and classifies seven techniques used in biogas upgrading, reported in academic and scientific publications. A 13-year review period (2008–2021) was considered. Lineal regression was used to analyze the publications number per year. Membranes use represents the largest proportion of publications (33%), while activated carbon (AC) reaches only 22%. However, the use and application of AC obtained the best trend as a publication topic, with a maximum value of R2 = 0.7882. This review documents publish works on obtaining and applying AC in biogas enrichment processes. It includes a review of the characteristics and generation rates of various residual lignocellulosic materials used in the synthesis of AC, the synthesis processes, the characterization techniques, and the final adsorption capacities.
Belen Lopez-Millan,Rafael Diaz de la Guardia,Heleia Roca-Ho,Carmen M García-Herrero,Jessie R Lavoie,Michael Rosu-Myles,Elena Gonzalez-Rey,Francisco O’Valle,Gabriel Criado,Mario Delgado,Pablo Menendez 생화학분자생물학회 2017 Experimental and molecular medicine Vol.49 No.-
Thalidomide is an immunomodulatory drug (IMiD) with proven therapeutic action in several autoimmune/inflammatory diseases; however, its inherent high toxicity has led to the development of more powerful and safer thalidomide analogs, including lenalidomide and pomalidomide. These are new generation IMiDs that exhibit direct antitumor activity as well as anti-inflammatory/immunomodulatory properties, and are FDA-approved for the treatment of several hematological malignances. Here we investigated the potential therapeutic effects of lenalidomide and pomalidomide in several experimental murine models of autoimmune/inflammatory diseases: 2,4,6-trinitrobenzene sulfonic acid- and dextran sulfate sodium-induced inflammatory bowel disease and type II collagen-induced arthritis. Lenalidomide displayed a strong therapeutic effect in all these models of autoimmune/inflammatory diseases, while the effect of pomalidomide was less pronounced. In vitro experiments confirmed the immunosuppressive effect of both IMiDs on the proliferative response of stimulated human lymphocytes and on the balance of secreted cytokines toward an anti-inflammatory profile. We conclude that lenalidomide may offer a therapeutic opportunity against autoimmune/inflammatory diseases.