Trabajo Precario y Vulnerabilidad Social de las Mujeres en la Periferia de la Zona Metropolitana de Guadalajara, México

Rangel Esquivel Jose Manuel,Villanueva Perez Nancy 부산외국어대학교 중남미지역원 2011 이베로아메리카 Vol.13 No.2

This study is derived from qualitative research during the period 2007-2009 in an urban marginalized sector at the periphery of the Guadalajara Metropolitan Area (GMA). The poverty conditions for women and their households make the work one of the main resources to confront and cover the most basic needs. The impact of global processes of crisis and economic restructuration, as well as labor flexibility trends over the operation of labor markets (Garcia y Oliveira 1994, 1998; Oliveira y Ariza 1998, 2000, 2001) have been highlighted in its precariousness, situations that have affected the conditions of work for women. From a multidimensional perspective, it is analyzed the diverse types and forms of precarious work for women, as well as the social vulnerability in which they inhabit; this framework proposed by Caroline(1996) allows to visualize the three levels in which it increases or decreases when the units of analysis are based on the individual, the household and the community. The leads to a holistic comprehension of the scenarios in which vulnerability acquires relevant overtones in order to deepen on the different dynamics and processes in which feminine work is immerse. In this sense, with an approximation of the social actors situated in this precarious stage, it is considered from the standpoint of Rocio(2003, 150), that “the study of subjectivity cannot be ignored when seeking to understand changing and dynamic processes of the phenomena of social vulnerability and the roll that plays the access of work in the struggle for survival”. Hence that the deep interviews with a biographical approach realized to women of urban sector contribute to the construction of the meanings the practices around feminine work.

Higher Education and Employment Policies in Mexico & Thailand in The 90`s

( Ernesto Rangel ) 충남대학교 교육연구소 2003 교육연구논총 Vol.24 No.2

SYNTHESIS OF MESOPOROUS OF NyTi1-xCexO2-y STRUCTURES AND ITS VISIBLE LIGHT INDUCED PHOTOCATALYTIC PERFORMANCE

R. RANGEL,J. D. GARCÍA-ESPINOZA,I. ESPITIA,P. QUINTANA,P. BARTOLO-PÉREZ,J. J. ALVARADO-GIL,R. TREJO-TZAB 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2013 NANO Vol.8 No.5

The present work was addressed to study the visible light induced performance as photocatalysts of mesoporous NyTi1–xCexO2–y structures obtained under microwave irradiation. The titanium dioxide (TiO2) was doped with cerium and nitrogen in order to improve the quantum efficiency of the TiO2 and to shift its adsorption spectra to the visible region. The prepared meso-powders were analyzed by means of X-ray diffraction (XRD), scanning Electron microscopy (SEM), infrared (IR) spectroscopy, transmission electronic microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The surface area was evaluated by means of the Brunauer-Emmett-Teller (BET) method and ultraviolet (UV)-visible diffuse reflectance measurements were performed in order to determine the band gap energy. In addition, the photocatalytic activity of the samples was evaluated by monitoring the photodegradation of methylene blue (MB) under UV and visible light energy irradiation. The results show that our methodology is an effective way for incorporating cerium and nitrogen into TiO2 compound, which in turn, increases its photocatalytic activity. The diffuse reflectance analysis confirms that the absorption edge was shifted towards the visible region of the optical spectrum. The XRD diffraction patterns indicate homogeneous solid solutions in which prevails the anatase phase. It was observed a reduction in crystal size from 13.1 nm to 7.7 nm for NyTi0.98Ce0.02O2–y in comparison to TiO2. The textural properties of the synthesized compounds were determined, by means of adsorption isotherms indicating the formation of mesoporous structures. IR spectra show characteristic vibration signals attributed to Ti–O–Ti bonds, as well as vibrations assigned to cerium and nitrogen bonds. The XPS analyses evidence the presence of Ce3+/Ce4+ redox couple and Ti–N bonds. The photocatalityc efficiency was evaluated in the degradation of MB monitoring the absorbance change at 664 nm. The degradation of this compound was 91.4% using NyTi0.98Ce0.02O2–y as photocatalyst under UV energy in 90 min. Also 38.7% of MB degradation was achieved in 150 min under visible light radiation.

Advantages of Hydrothermal Synthesis to Produce Tunable TiO2 Nanomicro Sized Photocatalysts and Their Effect in Lignin Degradation

R. Rangel,J. A. Cortes,J. Lara,P. QUINTANA,J. J. ALVARADO-GIL,O. Contreras 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2015 NANO Vol.10 No.3

Studies on photocatalytic degradation of lignin are scarce, even though it is an effective method for treatment of industrial effluents. In the present work, an advanced oxidation process (AOPs), leading to the photodegradation of lignin aqueous solutions, is proposed by using microstructured (T-MT) and nanostructured (T-NT) titanium dioxide compounds. Hydrothermal synthesis, in accordance with an experimental factorial design considering time of synthesis, NaOH concentration and synthesis temperature, was used to produce tunable TiO2 photocatalysts for further study of its effects on the degradation of lignin. Photocatalytic reactions were conducted in a micro reactor batch system under UV irradiation. The catalysts were analyzed by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), surface area and porosity analyzer (BET), energy-dispersive X-ray spectroscopy (EDS) and UV-Vis diffuse reflectance spectroscopy. In order to optimize the yield reaction, an experimental factorial design was performed. According to our results, nanostructured TiO2 consisting in different structural features and light absorption properties were produced using this method. It is shown that T-MT and T-NT compounds exhibit a wide range of values, for the kinetic parameters, in photoinduced degradation of methylene blue (MB) and lignin.

Topical and Systemic Anti-Inflammatory Effects of Echinodorus macrophyllus (Kunth) Micheli (Alismataceae)

Ellen Tanus-Rangel,Scheila R. Santos,Lousa˜ Lopes,Vaˆnia Noldin,Franco D. Monache,Valdir Cechinel-Filho,Domingos T.O. Martins 한국식품영양과학회 2010 Journal of medicinal food Vol.13 No.5

Echinodorus macrophyllus leaf has been used in Brazilian folk medicine to treat inflammatory conditions and kidney dysfunctions. The present study evaluated the effects of leaf ethanolic extract from E. macrophyllus (EEEm) in acute and subchronic models of inflammation. The EEEm was found to cause significant and potent inhibition of carrageenan- and dextran-induced paw edema in rats and marked decreases in the exudate volume and leukocyte migration in rats with carrageenan-induced pleurisy, the vascular permeability increase induced by intraperitoneal acetic acid, and the croton oil-induced topical ear edema in mice. On the other hand, the EEEm was not active in the test model of cotton pellet-induced granuloma in rats. Phytochemical analysis with E. macrophyllus leaves revealed the presence of triterpenoids, steroids, flavones, flavonols, and xanthones. Two flavonoids were isolated from the ethyl acetate fraction and identified as isovitexin and vitexin. Our results support the traditional use of E. macrophyllus leaves in the treatment of acute inflammatory conditions

Alcohol dehydrogenase 1 participates in the Crabtree effect and connects fermentative and oxidative metabolism in the Zygomycete Mucor circinelloides

Rosa Angélica Rangel-Porras,Sharel P. Díaz-Pérez,Juan Manuel Mendoza-Hernández,Pamela Romo-Rodríguez,Viridiana Alejandre-Castañeda,Marco I Valle-Maldonado,Juan Carlos Torres-Guzmán,Gloria Angélica Gon 한국미생물학회 2019 The journal of microbiology Vol.57 No.7

Mucor circinelloides is a dimorphic Zygomycete fungus that produces ethanol under aerobic conditions in the presence of glucose, which indicates that it is a Crabtree-positive fungus. To determine the physiological role of the alcohol dehydrogenase (ADH) activity elicited under these conditions, we obtained and characterized an allyl alcohol-resistant mutant that was defective in ADH activity, and examined the effect of adh mutation on physiological parameters related to carbon and energy metabolism. Compared to the Adh+ strain R7B, the ADH-defective (Adh-) strain M5 was unable to grow under anaerobic conditions, exhibited a considerable reduction in ethanol production in aerobic cultures when incubated with glucose, had markedly reduced growth capacity in the presence of oxygen when ethanol was the sole carbon source, and exhibited very low levels of NAD+-dependent alcohol dehydrogenase activity in the cytosolic fraction. Further characterization of the M5 strain showed that it contains a 10-bp deletion that interrupts the coding region of the adh1 gene. Complementation with the wild-type allele adh1+ by transformation of M5 remedied all the defects caused by the adh1 mutation. These findings indicate that in M. circinelloides, the product of the adh1 gene mediates the Crabtree effect, and can act as either a fermentative or an oxidative enzyme, depending on the nutritional conditions, thereby participating in the association between fermentative and oxidative metabolism. It was found that the spores of M. circinelloides possess low mRNA levels of the ethanol assimilation genes (adl2 and acs2), which could explain their inability to grow in the alcohol.

Synthesis of Al₂O₃/Ti₃Al composites by in-situ displacement reactions

Enrique Rocha-Rangel 한양대학교 세라믹연구소 2008 Journal of Ceramic Processing Research Vol.9 No.1

The employment of aluminothermic reactions of displacement as an alternative for the production of Al₂O₃/Ti₃Al composite materials has been investigated. Compacted samples from an intensely ground mixture of powders of TiO₂+Al₂O₃ +Al were sintered at 1500ºC during 1 hour by hot pressing in an argon atmosphere. The TiO₂ is used as predecessor to generate in-situ Al₂O₃ via its reduction by means of metallic Al. Al reacts also in a simultaneous way with the reduced titanium to form an intermetallic alloy of the type TixAly. The Al₂O₃ employed in the precursor materials is used as a way for the dissipation of the heat build-up during the aluminothermic reduction of the TiO₂. The results of the characterizations indicate that Al₂O₃- based composite materials were obtained with reinforcement particles of TixAly. The microstructure of these materials is dense, fine and homogeneous. The preliminary characterization of the microstructure and its composition features subsequent to the cycle of in-situ processing are presented here. The employment of aluminothermic reactions of displacement as an alternative for the production of Al₂O₃/Ti₃Al composite materials has been investigated. Compacted samples from an intensely ground mixture of powders of TiO₂+Al₂O₃ +Al were sintered at 1500ºC during 1 hour by hot pressing in an argon atmosphere. The TiO₂ is used as predecessor to generate in-situ Al₂O₃ via its reduction by means of metallic Al. Al reacts also in a simultaneous way with the reduced titanium to form an intermetallic alloy of the type TixAly. The Al₂O₃ employed in the precursor materials is used as a way for the dissipation of the heat build-up during the aluminothermic reduction of the TiO₂. The results of the characterizations indicate that Al₂O₃- based composite materials were obtained with reinforcement particles of TixAly. The microstructure of these materials is dense, fine and homogeneous. The preliminary characterization of the microstructure and its composition features subsequent to the cycle of in-situ processing are presented here.

Studying the wetting of carbon-coated alumina substrates by different aluminum alloys

Enrique Rocha Rangel,M. Socorro Moreno Guerrero,xico) 한양대학교 세라믹연구소 2006 Journal of Ceramic Processing Research Vol.7 No.1

The wetting of alumina ceramics was studied as a function of time and temperature by the sessile drop method using vacuum pressures of 10−5 Pa. Contact angles as small as 38 degrees were obtained for the combination carbon coated alumina and an Al-2.5 at.% La alloy, in a time of 4500s and at a temperature of 1300 oC. On the other hand, for the single system aluminaaluminum the final contact angle was of 82 degrees after 7200 seconds at the same temperature. Considering the free formation energy of different oxides and carbides that can be formed between elements used in the present experiments are favorable thermodynamically and considering the observation of undercutting of the substrate and ridge formation at the leading edge of the liquid aluminum in all samples it can be concluded that wetting is enhanced thanks to different chemical reactions that occur at the ceramic-metal interface.

Preparation of Water-Soluble Chitosan and Aloe vera Mucilage and Their Use for Assembly of Polyelectrolyte Complexes

( Adriana M. Rangel-rodriguez ),( J. Adriana Sañudo-barajas ),( Nagamani Balagurusamy ),( Louise Wicker ),( Rosabel Velez-de-la-rocha ),( Juan Carlos Contreras-esquivel ) 한국키틴키토산학회 2018 한국키틴키토산학회지 Vol.23 No.2

In this work, the preparation and characterization of water-soluble polysaccharides from chitosan and Aloe vera was studied. The water-soluble polysaccharides were used to study polyelectrolyte complexes. The reaction time effect for chitosan hydrolysis by endo-chitosanase was studied at 40ºC and pH 5.00 to produce water soluble chitosan (WSCh). The physico-chemical characteristics of chitosan hydrolysates, water-soluble A. vera polysaccharides and polyelectrolyte complexes were determined. After 3 h of chitosan processing, a viscosity reduction of 90%, while only 2.3% of reducing sugars were released. A WSCh was recover by ultrafiltration (1 kDa) from chitosan hydrolysate after 12 h and was spray-dried with a yield of 9.7%. Cold-water extraction of A. vera mucilage from pulp gives a crude polysaccharide yield of 0.81 g/kg (wet basis) based on whole leaf weight. The water isolated mucilage is composed of a mixture of protein and mannan rich-polysaccharide. The results show WSCh’s association capacity with A. vera mucilage by electrostatic interaction.

Fracture toughness enhancement for metal-reinforced alumina

Enrique Rocha-Rangel,Elizabeth Refugio-García,José G. Miranda-Hernández,Eduardo Terrés-Rojas 한양대학교 세라믹연구소 2009 Journal of Ceramic Processing Research Vol.10 No.6

With the idea to determine ways of tailoring alumina (Al2O3) in order that one or more toughening mechanisms are activated in service, investigations about the production of Al2O3-based composites with different reinforcement metals and intermetallics have been carried out. The synthesis of composites materials has been made by means of both; liquid and solid pressureless sintering of an intensive mechanical mixture of powders. With the use of some metals in the chemical formulations, significant improvements in ceramic toughness have been reported. From the fracture toughness measurements and microstructural observations, it can be concluded that the toughening mechanism in Al2O3/metal reinforced composites is due to crack bridging and crack deflection. With the idea to determine ways of tailoring alumina (Al2O3) in order that one or more toughening mechanisms are activated in service, investigations about the production of Al2O3-based composites with different reinforcement metals and intermetallics have been carried out. The synthesis of composites materials has been made by means of both; liquid and solid pressureless sintering of an intensive mechanical mixture of powders. With the use of some metals in the chemical formulations, significant improvements in ceramic toughness have been reported. From the fracture toughness measurements and microstructural observations, it can be concluded that the toughening mechanism in Al2O3/metal reinforced composites is due to crack bridging and crack deflection.