30 results on '"Natera J"'
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2. Fatigue of Steels Used in the Manufacture of Components for Heavy Load Vehicles
- Author
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Ramírez-Natera, J. J., primary, Salazar, C. A., additional, Rodríguez, A. Z., additional, Pérez-González, F. A., additional, Ramírez-Ramírez, J. H., additional, García, I., additional, Garza-Montes-de-Oca, N. F., additional, and Colás, R., additional
- Published
- 2018
- Full Text
- View/download PDF
3. Nutritional chemical characterization and phytochemical analysis of fruits of Jarilla caudata (Caricaceae) from Jalisco, Mexico
- Author
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González González, M. F., Zamora Natera, J. F., Vioque, Javier, Zañudo Hernández, J., Ruiz López, M. A., Ramírez López, C. B., Consejo Nacional de Ciencia y Tecnología (México), and Consejo Superior de Investigaciones Científicas (España)
- Subjects
Minerals ,Edible fruits ,Secondary metabolites ,Amino acids ,Plant Science ,Phenolic compounds ,Ecology, Evolution, Behavior and Systematics - Abstract
12 Páginas.--2 Figuras.-- 4 Tablas, Antecedentes y Objetivos: En algunos países, los habitantes de las comunidades rurales complementan su dieta con frutos obtenidos de plantas silvestres, los cuales generalmente carecen de información nutricional y fitoquímica, como ocurre con los frutos de las especies endémicas en México del género Jarilla (Caricaceae). Por lo tanto, el objetivo de esta investigación fue estudiar la composición nutricional de frutos de Jarilla caudata en términos de su análisis químico proximal, contenido de minerales y aminoácidos, así como determinar la presencia de metabolitos secundarios, contenido total de compuestos fenólicos y flavonoides. Métodos: Los frutos se colectaron en el municipio Teocuitatlán de Corona, Jalisco, en julio de 2018 y 2019. Para determinar la composición químico proximal se siguieron los métodos oficiales de análisis de AOAC. El contenido de minerales se determinó por espectrofotometría de absorción atómica y los aminoácidos por cromatografía de líquidos de alta resolución (HPLC). Para el análisis de metabolitos secundarios se utilizaron diversos reactivos, y el contenido de compuestos fenólicos y flavonoides totales se cuantificó por espectrofotometría. Resultados clave: En comparación con otros frutos silvestres de la familia Caricaceae, los resultados indicaron que los frutos de J. caudata representan una buena fuente de carbohidratos y proteínas (35.7 y 18.9 g/100 g respectivamente), así como de algunos minerales (K, P y Ca). Se observó un pobre perfil y contenido de aminoácidos. El promedio de compuestos fenólicos totales fue de 387.5 mg GAE/100 mg, mientras que el de flavonoides totales fue de 56.5 mg QE/100 mg. No se detectaron compuestos considerados tóxicos o antinutricionales como alcaloides y glucósidos cianogénicos. Conclusiones: Durante el verano, los frutos de J. caudata pueden tener un papel importante como complemento alimenticio para los habitantes de la región de Teocuitatlán de Corona, aportando diferentes nutrientes, particularmente carbohidratos y proteínas, así como otros compuestos con efectos favorables para la salud como los polifenoles., [EN] Background and Aims: In some countries, the inhabitants of rural communities supplement their diet with fruits obtained from wild plants, which usually lack nutritional and phytochemical information, as occurs with the fruits of the Mexican endemic species of the genus Jarilla (Caricaceae). Therefore, the aim of this research was to study the nutritional composition ofJarilla caudatafruits in terms of their proximal chemical analysis, mineral content and amino acid composition, and determine the presence of secondary metabolites, the total content of phenolic compounds and flavonoids. Methods: The fruits were collected in the municipality Teocuitatlán de Corona, Jalisco, in July 2018 and 2019. The proximal chemical composition was analyzed using the official methods of analysis (AOAC), the mineral content was determined by means of atomic absorption spectrophotometry, while the amino acids were analyzed by high performance liquid chromatography (HPLC). Various reagents were used for the preliminary determination of secondary metabolites. The content in phenolic compounds and total flavonoids was quantified by spectrophotometry.Key results: In comparison with other fruits of the Caricaceae family, the results indicated that the fruits ofJ. caudatarepresent a good source of carbohydrates and proteins (35.7 and 18.9 g/100 g, respectively), as well as some minerals (K, P and Ca). A poor amino acid profile and content was found. The average con-tent of total phenolic compounds was 387.5 mg GAE/100 mg, while that of flavonoids was 56.5 mg QE/100 mg. Compounds considered toxic or antinutritional, such as alkaloids and cyanogenic glycosides, were not detected.Conclusions: During summer the fruits of J. caudatacan play an important role as a food supplement for the inhabitants of the region of Teocuitatlán de Corona, providing different nutrients, particularly carbohydrates and proteins, as well as other compounds with favorable health effects, such as polyphenols, Este estudio fue apoyado por el Consejo Nacional de Ciencia y Tecnología (CONACYT) mediante una beca otorgada a MFGG (No de beca: 1073088), y por el Consejo Superior de Investi-gaciones Científicas de Sevilla (España), mediante el proyecto I-COOP2021 concedido a JVP
- Published
- 2022
4. Caracterización químico nutricional y análisis fitoquímico de frutos de Jarilla caudata (Caricaceae) de Jalisco, México
- Author
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Consejo Nacional de Ciencia y Tecnología (México), Consejo Superior de Investigaciones Científicas (España), González González, M. F., Zamora Natera, J. F., Vioque, Javier, Zañudo Hernández, J., Ruiz López, M. A., Ramírez López, C. B., Consejo Nacional de Ciencia y Tecnología (México), Consejo Superior de Investigaciones Científicas (España), González González, M. F., Zamora Natera, J. F., Vioque, Javier, Zañudo Hernández, J., Ruiz López, M. A., and Ramírez López, C. B.
- Abstract
Antecedentes y Objetivos: En algunos países, los habitantes de las comunidades rurales complementan su dieta con frutos obtenidos de plantas silvestres, los cuales generalmente carecen de información nutricional y fitoquímica, como ocurre con los frutos de las especies endémicas en México del género Jarilla (Caricaceae). Por lo tanto, el objetivo de esta investigación fue estudiar la composición nutricional de frutos de Jarilla caudata en términos de su análisis químico proximal, contenido de minerales y aminoácidos, así como determinar la presencia de metabolitos secundarios, contenido total de compuestos fenólicos y flavonoides. Métodos: Los frutos se colectaron en el municipio Teocuitatlán de Corona, Jalisco, en julio de 2018 y 2019. Para determinar la composición químico proximal se siguieron los métodos oficiales de análisis de AOAC. El contenido de minerales se determinó por espectrofotometría de absorción atómica y los aminoácidos por cromatografía de líquidos de alta resolución (HPLC). Para el análisis de metabolitos secundarios se utilizaron diversos reactivos, y el contenido de compuestos fenólicos y flavonoides totales se cuantificó por espectrofotometría. Resultados clave: En comparación con otros frutos silvestres de la familia Caricaceae, los resultados indicaron que los frutos de J. caudata representan una buena fuente de carbohidratos y proteínas (35.7 y 18.9 g/100 g respectivamente), así como de algunos minerales (K, P y Ca). Se observó un pobre perfil y contenido de aminoácidos. El promedio de compuestos fenólicos totales fue de 387.5 mg GAE/100 mg, mientras que el de flavonoides totales fue de 56.5 mg QE/100 mg. No se detectaron compuestos considerados tóxicos o antinutricionales como alcaloides y glucósidos cianogénicos. Conclusiones: Durante el verano, los frutos de J. caudata pueden tener un papel importante como complemento alimenticio para los habitantes de la región de Teocuitatlán de Corona, aportando diferentes nutrientes, particularmente, [EN] Background and Aims: In some countries, the inhabitants of rural communities supplement their diet with fruits obtained from wild plants, which usually lack nutritional and phytochemical information, as occurs with the fruits of the Mexican endemic species of the genus Jarilla (Caricaceae). Therefore, the aim of this research was to study the nutritional composition ofJarilla caudatafruits in terms of their proximal chemical analysis, mineral content and amino acid composition, and determine the presence of secondary metabolites, the total content of phenolic compounds and flavonoids. Methods: The fruits were collected in the municipality Teocuitatlán de Corona, Jalisco, in July 2018 and 2019. The proximal chemical composition was analyzed using the official methods of analysis (AOAC), the mineral content was determined by means of atomic absorption spectrophotometry, while the amino acids were analyzed by high performance liquid chromatography (HPLC). Various reagents were used for the preliminary determination of secondary metabolites. The content in phenolic compounds and total flavonoids was quantified by spectrophotometry.Key results: In comparison with other fruits of the Caricaceae family, the results indicated that the fruits ofJ. caudatarepresent a good source of carbohydrates and proteins (35.7 and 18.9 g/100 g, respectively), as well as some minerals (K, P and Ca). A poor amino acid profile and content was found. The average con-tent of total phenolic compounds was 387.5 mg GAE/100 mg, while that of flavonoids was 56.5 mg QE/100 mg. Compounds considered toxic or antinutritional, such as alkaloids and cyanogenic glycosides, were not detected.Conclusions: During summer the fruits of J. caudatacan play an important role as a food supplement for the inhabitants of the region of Teocuitatlán de Corona, providing different nutrients, particularly carbohydrates and proteins, as well as other compounds with favorable health effects, such as polyphenols
- Published
- 2022
5. Forage potential of three wild species of genus Lupinus (Leguminosae) from Mexico.
- Author
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Zamora-Natera, J. F., Rodriguez-Macias, R., Salcedo-Perez, E., García-Lopez, P., Barrientos-Ramirez, L., Vargas-Radillo, J., Soto-Velasco, C., and Ruiz-López, M. A.
- Subjects
- *
FORAGE , *LUPINES , *LEGUMES , *SPECIES , *FORAGE plants , *IRRIGATION - Abstract
The study of new legumes species in terms of yield and quality of forage under cultivation conditions is essential to improving the productivity of animal production. We evaluated the yield and nutritional quality of forage under irrigation conditions for three wild lupin species from Mexico (L. exaltatus, L. mexicanus, and L. rotundiflorus) at different stages of maturity. The experiment was conducted from November 2016 to March 2017 in Jalisco, Mexico. In general, the dry matter (DM) in all species increased with advancing maturity, but L. exaltatus presented the best production of forage 15,143 kg/ha-1 DM, followed by L. mexicanus (9,140 kg/ha-1 DM) on the third sampling date. The low forage yield in L. rotundiflorus was compensated by a higher average protein content (171.2 g/kg). The highest P and K content was recorded in L. rotundiflorus, whereas Ca and Mg were higher in the forage of L. mexicanus. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
6. Dry matter yield and nitrogen content in Lupinus spp. (Leguminosae) with potential as a green manure.
- Author
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Hernández, I. Zapata, Macías, R. Rodríguez, López, P. M. García, Perez, E. Salcedo, Rivera, A. H. Lara, and Natera, J. F. Zamora
- Subjects
GREEN manure crops ,LUPINES ,LEGUMES ,FACTORIAL experiment designs ,NITROGEN ,FOLIAGE plants - Abstract
The potential of Lupinus exaltatus, L. mexicanus, and L. rotundiflorus foliage as green manure in terms of total dry matter production and nitrogen (N) content was evaluated. This study was conducted from November 2015 to March 2016 in Zapopan Jalisco, México. The experiment was established in a randomized 3×7 block factorial design. Whole plants, leaves and stems were collected at different periods after sowing and analyzed for N and dry matter content. At the start of the experimental period, a slow growth was observed, based on dry matter production; however, at 93 days after sowing, both biomass and total N increased in the aerial part. The lowest and highest N content was found in L. rotundiflorus (1.2 to 4.0%). The highest dry matter and N accumulated in whole plants were found in L. exaltatus at 169 days after sowing with 21,605 and 410.6 kg ha
-1 , respectively. [ABSTRACT FROM AUTHOR]- Published
- 2019
- Full Text
- View/download PDF
7. Determination of correlation and path coefficients among vegetative and productive characteristics of cashewnut cultivars (Anacardium occidentale L.) at Madakkathara, Kerala, India
- Author
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Méndez-Natera, J. R.
- Subjects
path coefficient analysis ,correlación ,Cashewnut ,correlation ,Anacardium occidentale ,análisis de trayectoria ,Merey - Abstract
Los objetivos del presente trabajo fueron determinar las asociaciones entre el rendimiento de nueces por árbol en kg (RNA) con tres caracteres vegetativos del árbol: expansión (m) promedio del dosel o copa (EPD), circunferencia (cm) del tallo (CT) y altura (m) del árbol (AA) y con tres caracteres de la parte comestible: peso (g) de nuez (PN), peso (g) del pseudofruto (PPF) y relación PPF/PN y determinar los efectos directos e indirectos de estos caracteres sobre el RNA. Los coeficientes de correlación se calcularon a partir del promedio de tres repeticiones de un ensayo con 18 cultivares de merey con cuatro árboles por cultivar. Los niveles de significación fueron: 5% (*) y 1% (**). Se encontró que disminuciones del RNA estuvieron asociadas con incrementos del PPF (-0,645**) y de la relación PPF/PN (-0,522*). Un mayor PN estuvo asociado con un mayor PPF (0,812**). Aumentos del PPF se asociaron con incrementos en la relación PPF/PN (0,642**). Los árboles con una gran EPD tuvieron tallos más gruesos (0,560*) y árboles más altos (0,607**). Una mayor AA estuvo relacionada con una mayor CT (0,592**). El resto de los coeficientes de correlación no fueron significativos. El análisis de los coeficientes de trayectoria indicó que los caracteres que más afectaron directamente al RNA fueron: PPF (-1,761) y PN (0,985), los otros cuatro caracteres tuvieron efectos directos inferiores al efecto residual (0,689). Estos resultados indican que se puede obtener un mayor rendimiento de nueces por árbol mediante la selección de nueces más pesadas y pseudofrutos más livianos, por otra parte, los tres caracteres vegetativos del árbol evaluados mostraron efectos directos muy bajos sobre el RNA (< 0,186) y ninguna relación significativa. The objectives of this present study were to determine the associations among nut yield/tree (NYT) and three vegetative characteristics of trees: mean canopy (MC), shaft circumference (SC) and tree height (TH) and three characteristics of edible parts: nut weight (NW), apple weight (AW) and AW/NW ratio and to determine direct and indirect effects of these characters on the NYT. The correlation coefficients were calculated using the means of three replications of an experiment with 18 cashewnut cultivars with four trees/cultivar. The probability level was: 5% (*) and 1% (**). The NYT was correlated negatively with AW (-0.645**) and the AW/NW ratio (-0.522*). NW was positively correlated with AW (0.812**). AW was associated positively with AW/NW (0.642**). The MC was related positively with SC (0.560*) and TH (0.607**). SC was correlated positively with TH (0.592**). The other correlation coefficients were not significant. The path coefficient analysis indicated that the characteristics that more directly affected NYT were: AW (-1.761) and NW (0.985), the other four characteristics had direct affects inferior to the residual effect (0.689). These results indicate that increments of nut yield/tree can be obtained by selecting heavier nuts and lighter apples, on the other hand, the three vegetative characters of tree showed very low direct effects on the NYT (< 0.186) and they did not show any significant association with it.
- Published
- 2003
8. Effect of two stand population and two fertilization levels on seed cotton yield and its components in three cotton cultivars (Gossypium hirsutum L.) in the savanna of Jusepin
- Author
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Méndez-Natera, J. R.
- Subjects
Fertilización con NPK ,densidad de siembra ,Savanna ,Sabana ,Gossypium hirsutum ,Cultivares de algodón ,NPK fertilization ,stand population ,Cotton cultivars - Abstract
El objetivo del presente trabajo fue determinar el efecto de dos distancias entre plantas (DEP) (0,15 y 0,25 m) y dos niveles de fertilización (NF) (250 y 500 kg de 12-24-12/ha) sobre el rendimiento de algodón en rama y sus componentes en tres cultivares de algodón [Deltapine Acala 90 (DPA90), Cabuyare (CAB) y Deltapine 16 (DP16)] en la sabana de Jusepín, estado Monagas. El ensayo se realizó en un suelo Ultisol de sabana con pH 4,7; bajo en materia orgánica, P, K y Cu, medio en Ca, Mg y Mn y trazas de Al, alto en Fe y Zn y textura FAa, la profundidad de muestreo fue 25 cm. El diseño estadístico utilizado fue el de bloques al azar en arreglo factorial. Cada unidad experimental estuvo constituida por tres hileras de 5 m con una separación entre hileras de 0,80 m. Se realizó un reabono con urea a los 18 días después de la siembra a razón de 150 kg/ha. No se encontraron diferencias significativas para ninguna de las fuentes de variación para: peso de bellota (9,37 g) y número de semillas/bellota (28,3 semillas). Se encontraron diferencias significativas para la interacción Cultivares*DEP para: número de bellotas/planta: Las plantas de DPA90 fueron más prolíficas a 0,25 m, mientras las plantas de CAB y DP16 fueron más prolíficas a 0,15 m entre plantas. Se encontraron diferencias significativas para la interacción de los tres factores (cultivares*DEP*FL) para: peso de algodón en rama/planta (PARP): en la dosis de 250 kg/ha, DPA90 a 0,25 m tuvo un mayor PARP que el resto de los cinco tratamientos, mientras que a 500 kg/ha, este tratamiento sólo superó a CAB a 0,15 m entre plantas. Solamente se encontraron diferencias significativas para el número de plantas cosechadas/parcela (NPCP) en el factor DEP, existiendo un mayor NPCP a 0,15 m. Se realizaron dos análisis de covarianza para el rendimiento de algodón en rama/ha (RARH) en función del NPCP en cada DEP: para la DEP de 0,15 m sólo se encontraron diferencias significativas para NF, el mayor RARH (1498,6 kg/ha) se obtuvo con la mayor dosis de fertilizante, mientras que para la DEP de 0,25 sólo se encontraron diferencias para los cultivares: El mayor RARH correspondió a DPA90 con 1550,7 kg/ha. En conclusión, para altas densidades de siembra (83.333 plantas/ha) de cualquiera de los tres cultivares de algodón evaluados, se debería aplicar una mayor cantidad de fertilizante (500 kg de 12-24-12/ha), mientras que para bajas densidades de siembra (50.000 plantas/ha) debería sembrarse el cultivar Deltapine Acala 90 en lugar de Deltapine 16 y Cabuyare, sin importar el nivel de fertilización. The present work had as objective to determine the effect of two distances between plants (DBP) (0.15 and 0.25 m) and two fertilization levels (FL) (250 and 500 kg of 12-24-12/ha) on the seed cotton yield and its components in three cotton cultivars [Deltapine Acala 90 (DPA90), Cabuyare (CAB) and Deltapine 16 (DP16)] in the savanna of Jusepín, Monagas state. The experiment was carried out in an Ultisol soil with pH 4.7; low levels of organic matter, P, K and Cu, medium levels of Ca, Mg and Mn y no-Al, high levels of Fe and Zn y texture FAa, soil's sample depth was 25 cm. A three factor randomized complete block design was used. A three-row block of each experimental unit was planted in rows 5 m long and 0.8 m apart. Urea was applied at 18 days after sowing at 150 kg/ha. There were not significant differences for any variation source for: boll weight (9.37 g) and seeds/boll (28.3 seeds). There were significant differences for the interaction Cultivars*DBP for: bolls/plant: DPA90 plants were more prolific at 0.25 m, while CAB and DP16 plants were more prolific at 0.15 m. There were significant differences for the three factor interaction (cultivars*DBP*FL) for: seed cotton weight/plant (SCWP): at 250 kg 12-24-12/ha, DPA90 sowed at 0.25 m had a bigger SCWP that the rest of the five treatments, while at 500 kg/ha, this treatment only overcame the treatment of CAB sowed at 0.15 m. There were only significant differences for number of harvested plants/plot (NHPP) at DBP factor, there was a greater NHPP at 0.15 m. Two covariance analysis were made for seed cotton yield /ha (SCYH) in function of NHPP at each DBP: for 0.15-m DBP, there were only significant differences for FL, the greater SCYH (1498.6 kg/ha) was obtained with the higher fertilizer dose, while 0.25-m DBP, there were only differences for cultivars: The greater SCYH corresponded to DPA90 with 1550.7 kg/ha. These results suggest: a) for high stands (83,333 plants/ha), any of three cotton cultivars could be sowed, applying a higher amount of fertilizer (500 kg of 12-24-12/ha), while for low stands (50,000 plants/ha) cultivar Deltapine Acala 90 should be sowed instead of Deltapine 16 and Cabuyare, no matter the fertilization level.
- Published
- 2003
9. Effect of several tillage methods and the form of urea placement on seed yield and its components of three sesame varieties (Sesamum indicum L.)
- Author
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Méndez-Natera, J. R., Medina L., O. H., Fendel, J. E., and Merazo, J. F.
- Subjects
urea placement ,Métodos de labranza ,ajonjolí ,aplicación de urea ,cultivars ,sesame ,cultivares ,Tillage methods - Abstract
El objetivo del presente trabajo fue determinar el efecto de cuatro métodos de labranza y la forma de aplicación del reabono con urea sobre el rendimiento de semillas y sus componentes en tres cultivares de ajonjolí. El experimento se llevo a cabo en un suelo Ultisol francoarenoso. Se utilizaron cuatro métodos de labranza: Cincel: un pase de arado de cincel 30 días antes de la siembra (DAS) y un pase de rotativa 1 DAS; Rastra: tres pases de rastra a los 30; 15 y 1 DAS (método convencional); Cincel + Rastra: un pase de arado de cincel 30 DAS y tres pases de rastra a los 30; 15 y 1 DAS y Labranza mínima: un pase de rotativa 1 DAS. Se sembraron tres cultivares de ajonjolí: Glauca, Acarigua y Blanca y la urea se aplicó (200 kg/ha) de dos formas: bandas enterradas y superficiales. La forma de aplicación de urea, no afectó el rendimiento de semillas, ni ninguno de sus componentes. Con la labranza mínima se produjeron pérdidas considerables de plantas, en cambio, con la labranza convencional se logró una mayor emergencia y menor mortalidad de las plantas. Los mayores rendimientos de semillas se encontraron en Glauca con rastra, en Blanca con cincel y en Acarigua con rastra o con cincel. En cincel + rastra, los tres cultivares tuvieron producciones de semillas similares entre sí, pero en cincel y en labranza mínima, Blanca produjo un mayor rendimiento de semillas y en rastra, Glauca tuvo el mayor rendimiento. The objective of this study was to determine the effect of four tillage methods and placement of urea on seed yields and its components in three sesame varieties. The experiment was carried out in a Ultisol sandy loam soil. Four tillage methods were used: Chisel: a pass of chisel-plow 30 days before sowing (DBS) and a pass of rotary cultivator 1 DBS; Harrow: three passes of harrow at 30, 15 and 1 DBS (conventional method); Minimum tillage: a pass of rotary cultivator 1 DBS; and Chisel + Harrow: a pass of chisel 30 DBS and three passes of harrow at 30, 15 and 1 DBS. Three sesame cultivars were sown: Glauca, Acarigua and Blanca and urea was applied (200 kg/ha) in two forms: banded into the soil and superficial. Urea placement did not affect seed yields and its components. Minimum tillage caused considerable losses of plants; on the other hand, three harrow passes caused a bigger emergence and lower plant mortality. The biggest seed yields were found in Glauca with Harrow, in Blanca with Chisel and in Acarigua with Harrow or Chisel. In Chisel + Harrow, the three cultivars had similar yields, but in Chisel and Minimum tillage, Blanca had greater yields in seeds and harrow, and Glauca had the greatest yields.
- Published
- 2002
10. Determination of mitotic cycle of two cultivars of Gossypium hirsutum L. and two ecotypes of Gossypium barbadense L.
- Author
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Ferrer-Pereira, H. E.; UFPR, Alcorcés-de-Guerra, N. C.; vene, Méndez-Natera, J. R.; venezuela, Ferrer-Pereira, H. E.; UFPR, Alcorcés-de-Guerra, N. C.; vene, and Méndez-Natera, J. R.; venezuela
- Abstract
Determination of mitotic cycle of two cultivars of Gossypium hirsutum L. and two ecotypes of Gossypium barbadense L., Determinación del ciclo mitótico de dos cultivares de Gossypium hirsutum L. y dos ecotipos de Gossypium barbadense L., Determinação do ciclo mitótico de dois cultivares de Gossypium hirsutum L. e dois ecótipos de Gossypium barbadense 
- Published
- 2007
11. Comprimentos cromossômicos de dois cultivares de Gossypium hirsutum L. e dois ecótipos de Gossypium barbadense L.
- Author
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Ferrer-Pereira, H. E., primary, Méndez-Natera, J. R., additional, and Alcorcés-de-Guerra, N. C., additional
- Published
- 2007
- Full Text
- View/download PDF
12. Determinação do ciclo mitótico de dois cultivares de Gossypium hirsutum L. e dois ecótipos de Gossypium barbadense L.
- Author
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Ferrer-Pereira, H. E., primary, Alcorcés-de-Guerra, N. C., additional, and Méndez-Natera, J. R., additional
- Published
- 2007
- Full Text
- View/download PDF
13. Genetic Studies in Upland Cotton (Gossypium hirsutum L.) II. General and Specific Combining Ability.
- Author
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Méndez-Natera, J. R., Rondón, A., Hernández, J., and Fernando Merazo-Pinto, J.
- Subjects
- *
COTTON varieties , *COTTON yields , *PLANT size , *FLOWERS , *PLANT stems ,COTTON genetics - Abstract
The present experiment was carried out to assess the general combining ability (GCA) and specific combining ability (SCA) of six important commercial cultivars of Gossypium hirsutum L. of Venezuela, viz., 'Deltapine 16', 'Tamcot-SP-21', 'Cabuyare', 'Stoneville', 'Ospino' and 'Acala 90-1' and their 15 F1 hybrids, respectively. The data were analyzed using Griffing's Model I Method II. Significant differences were found for all traits evaluated, except for seeds per boll and bolls per plant. Combining ability analysis of variance revealed significant differences for GCA and SCA effects among the parents and hybrids for almost all traits except for seed cotton yield ha-1 and fiber % for GCA and boll set, seed yield, and fiber % for SCA. The results suggested the presence of additive and non-additive gene action for almost all of the traits. The ratio GCA/SCA ranged from 0.59 for fiber fineness to 5.14 for plant height. Cultivars with the best (desired) GCA effects were cv. Cabuyare for blooming initiation, seed yield, and fiber fineness; Stoneville for plant height, stem diameter, number of fruit branches, number of set flowers, and boll weight; Tamcot-SP-21 for boll set and fiber fineness; Deltapine 16 for plant height, 100- seed weight and fiber length; Ospino for fiber strength. Also, the results revealed that Stoneville was the best general combiner for most of the traits. Finally, the correlations among GCA effects of the parents showed negative and significant associations of boll set with plant height and positive and significant associations of fruit branches with plant height, boll weight, and number of set flowers; of set flowers with plant height and boll weight; and of plant height with stem diameter. [ABSTRACT FROM AUTHOR]
- Published
- 2012
14. 15-Year Service Performance of Copper-Chromium-Arsenic Treated Poles of Araucaria spp. in Papua New Guinea and Some Preservative Retention Data.
- Author
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Chin, C. W., Natera, J., and McEvoy, C.
- Published
- 1988
15. MERCOSUR: Trends internationalization and technological capabilities,MERCOSUR: Tendencias de internacionalización y capacidades tecnológicas
- Author
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ISABEL ALVAREZ, Fischer, B. B., and Natera, J. M.
16. Epoxiconazole degradation in water samples: a comparative study of Fenton, photo-Fenton, solar photo-Fenton, and solar photolysis processes.
- Author
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Sacchetto JL, Medina LF, Toledo KI, Plem SC, Jalit Y, Gatica EA, Miskoski S, Natera J, Lépori CMO, and Massad WA
- Abstract
Epoxiconazole (EPO) is classified as a persistent organic pollutant due to its ability to persist in the environment for prolonged periods. Its degradation is pivotal in mitigating its environmental impact. This investigation focuses on assessing the degradation of EPO using various methodologies, namely Fenton, photo-Fenton, solar photo-Fenton, and solar photolysis, conducted in both Milli-Q water and groundwater. These experiments encompassed evaluations at both the standard pH typically used in photo-Fenton reactions and the natural pH levels inherent to the respective aqueous environments. Additionally, EPO degradation products were analyzed after a 60-min reaction. Notably, in systems utilizing groundwater, the inclusion of additional iron was unnecessary, as the naturally occurring iron content in the groundwater facilitated the intended processes. Specifically, in Milli-Q water, solar photo-Fenton demonstrated an EPO degradation efficiency of 97%. Furthermore, the substitution of Milli-Q water with groundwater in Fenton-like processes did not significantly affect the efficacy of EPO degradation. These findings underscore the potential of solar photo-Fenton as an economically viable and environmentally sustainable strategy for EPO degradation., (© 2024. The Author(s), under exclusive licence to the European Photochemistry Association, European Society for Photobiology.)
- Published
- 2024
- Full Text
- View/download PDF
17. A novel eco-friendly polymeric photosensitizer based on chitosan and flavin mononucleotide.
- Author
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Sacchetto J, Gutierrez E, Reta GF, Gatica E, Miskoski S, Montaña MP, Natera J, and Massad WA
- Subjects
- Flavin Mononucleotide chemistry, Flavins chemistry, Reactive Oxygen Species, Photosensitizing Agents chemistry, Chitosan
- Abstract
Flavin mononucleotide (FMN) is a dye belonging to the flavin family. These dyes produce photosensitized degradation of organic compounds via reaction with the excited states of the dye or with reactive oxygen species photogenerated from the triplet of the dye. This article presents a new polymeric dye (FMN-CS) composed of the photosensitizer FMN covalently bonded to chitosan polysaccharide (CS). FMN-CS obtained has a molecular weight of 230 × 10
3 g mol-1 and a deacetylation degree of 74.8%. The polymeric dye is an environmentally friendly polymer with spectroscopic and physicochemical properties similar to those of FMN and CS, respectively. Moreover, under sunlight, it is capable of generating1 O2 with a quantum yield of 0.31. FMN-CS, like CS, is insoluble in basic media. This allows easy recovery of the polymeric dye once the photosensitized process has been carried out and makes FMN-CS a suitable photosensitizer for the degradation of pollutants in contaminated waters. To evaluate whether FMN-CS may be used for pollutant degradation, the photosensitized degradation of two trihydroxybenzenes by FMN-CS was studied., (© 2023. The Author(s), under exclusive licence to European Photochemistry Association, European Society for Photobiology.)- Published
- 2023
- Full Text
- View/download PDF
18. Photocatalytic evaluation and characterization of TiO 2 -riboflavin phosphate film: analysis of reactive oxygen species.
- Author
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Possetto D, Gambetta C, Gatica E, Montaña MP, Porcal GV, Massad W, and Natera J
- Abstract
The effect of Riboflavin-5'-phosphate (RFPO
4 ) sensitization on photocatalytic properties of TiO2 film was studied. RFPO4 was adsorbed on film surface to investigate the photophysical properties of TiO2 upon blue-light photoexcitation. The film was characterized through scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, thermogravimetric analysis, and diffuse reflectance spectroscopy. The efficiency of the TiO2 /RFPO4 film was tested for pollutant elimination in aqueous media in a visible-light-driven system. The phenol paradigmatic model was employed in an aqueous solution as a contaminant target. TiO2 /RFPO4 sensitized photodegradation of phenol, which produces catechol, hydroquinone, and benzophenone, was monitored by absorption spectroscopy and HPLC. The results indicated that phenol degradation with TiO2 /RFPO4 film was due to the photogeneration of two reactive oxygen species, singlet molecular oxygen (O2 (1 Δg )) and superoxide radical anion (O2 ·- ) identified through specific detection techniques. The presence of O2 (1 Δg ) is reported here for the first time as generated from a sensitized TiO2 film upon visible-light photoirradiation. Based on the photophysical determinations, a photocatalytic mechanism for TiO2 /RFPO4 was established., (© 2022. The Author(s), under exclusive licence to European Photochemistry Association, European Society for Photobiology.)- Published
- 2023
- Full Text
- View/download PDF
19. Photo-Fenton and Riboflavin-photosensitized Processes of the Isoxaflutole Herbicide.
- Author
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Gatica E, Possetto D, Reynoso A, Natera J, Miskoski S, De Gerónimo E, Bregliani M, Pajares A, and Massad WA
- Subjects
- Kinetics, Light, Herbicides chemistry, Isoxazoles chemistry, Photochemical Processes, Photosensitizing Agents chemistry, Riboflavin chemistry
- Abstract
The proherbicide Isoxaflutole (IXF) hydrolyzes spontaneously to diketonitrile (DKN) a phytotoxic compound with herbicidal activity. In this work, the sensitized degradation of IXF using Riboflavin (Rf), a typical environmentally friendly sensitizer, Fenton and photo-Fenton processes has been studied. The results indicate that only the photo-Fenton process produces a significant degradation of the IXF. Photolysis experiments of IXF sensitized by Riboflavin is not a meaningful process, IXF quenches the Rf excited triplet (
3 Rf*) state with a quenching rate constant of 1.5 · 107 m-1 s-1 and no reaction is observed with the species O2 (1 Δg ) or O 2 · - generated from3 Rf*. The Fenton reaction produces no changes in the IXF concentration. While the photo-Fenton process of the IXF, under typical conditions, it produces a degradation of 99% and a mineralization to CO2 and H2 O of 88%. A rate constant value of 1.0 × 109 m-1 s-1 was determined for the reaction between IXF and HO˙. The photo-Fenton process degradation products were identified by UHPLC-MS/MS analysis., (© 2018 The American Society of Photobiology.)- Published
- 2019
- Full Text
- View/download PDF
20. Scavenging of photogenerated ROS by Oxicams. Possible biological and environmental implications.
- Author
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Ferrari GV, Natera J, Paulina Montaña M, Muñoz V, Gutiérrez EL, Massad W, Miskoski S, and García NA
- Subjects
- Anti-Inflammatory Agents, Non-Steroidal chemistry, Light, Meloxicam, Oxidation-Reduction, Photolysis radiation effects, Pyridines chemistry, Rhodamines chemistry, Riboflavin chemistry, Singlet Oxygen chemistry, Superoxides chemistry, Tryptophan chemistry, Tyrosine chemistry, Water Pollutants, Chemical chemistry, Free Radical Scavengers chemistry, Piroxicam analogs & derivatives, Piroxicam chemistry, Reactive Oxygen Species chemistry, Thiazines chemistry, Thiazoles chemistry
- Abstract
The profusely employed drugs Piroxicam (Piro), Tenoxicam (Teno) and Meloxicam (Melo) belonging to the non-steroidal antiinflammatory drug (NSAID) family of the Oxicams (Oxis) were studied in the frame of two specific conditions: (a) their ROS scavenging ability, in relation to a possible biological antioxidant action and (b) their photodegradability under environmental conditions, in the context of Oxi-contaminated waters. Singlet molecular oxygen (O2((1)Δg)) and superoxide radical anion (O2(-)) were photogenerated through Riboflavin (Rf, vitamin B2)-photosensitization in aqueous and aqueous-methanolic solutions in the presence of Oxi concentrations in the range 50-500 μM. The visible-light absorber vitamin is currently present in all types of natural waters and constitutes the most frequent endogenous photosensitizer in mammals. Hence, it was employed in order to mimic both natural sceneries of interest. All three Oxis quench O2((1)Δg) with rate constants in the order of 10(8)M(-1)s(-1) showing a significant photodegradation efficiency given by a dominant reactive fashion for deactivation of the oxidative species. Although this is not a desirable property in the context of photoprotection upon prolonged photoirradiation, constitutes in fact a promissory aspect for the degradation NSAIDs, in waste waters. Indirect evidence indicates that Melo is also oxidized through a O2(-)-mediated component. The simultaneous presence of Piro plus tryptophan or tyrosine under Rf-photosensitizing conditions, which has taken the amino acids as photooxidizable model residues in a proteinaceous environment, indicates that the NSAID induces a protection of the biomolecules against photodynamic degradation., (Copyright © 2015 Elsevier B.V. All rights reserved.)
- Published
- 2015
- Full Text
- View/download PDF
21. On the photooxidation of the multifunctional drug niclosamide. A kinetic study in the presence of vitamin B2 and visible light.
- Author
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Natera J, Gatica E, Challier C, Possetto D, Massad W, Miskoski S, Pajares A, and García NA
- Subjects
- Anions, Antioxidants chemistry, Kinetics, Lasers, Light, Methanol chemistry, Oxygen chemistry, Phenol chemistry, Phenols chemistry, Photolysis, Photosensitizing Agents chemistry, Reactive Oxygen Species chemistry, Singlet Oxygen, Spectrophotometry, Ultraviolet, Superoxides chemistry, Tryptophan chemistry, Water chemistry, Water Pollutants, Chemical chemistry, Niclosamide therapeutic use, Photochemical Processes, Riboflavin chemistry
- Abstract
Objectives: The multifunctional drug niclosamide (NSD), extensively employed therapeutically, is a frequent pollutant of surface waters. Considering the environmental importance of photodegradative processes for this type of contaminant, the kinetic and mechanistic aspects of the possible visible-light-mediated photooxidation of NSD were studied under naturalistic conditions., Methods: The visible-light absorber riboflavin (vitamin B2) was employed as a photosensitizer. The vitamin can usually be found in natural waters and is the most common endogenous photosensitizer in mammals. The interaction of NSD with electronically excited states of Rf and with photogenerated reactive oxygen species (ROS) was evaluated through conventional UV spectroscopy, laser flash photolysis, time-resolved phosphorescence detection of singlet molecular oxygen (O2((1)Δg)), and polarographic dosage of dissolved oxygen., Results: Ground state NSD quenched the long-lived triplet excited state of Rf ((3)Rf*) and the photogenerated ROS (O2((1)Δg)) and superoxide radical anion (O2•−). As a result, NSD was photooxidized. The rate constants for the interaction NSD-O2((1)Δg) are particularly low, in the order of 10(6)/M/s, although the whole interaction is attributable to a pure reactive process. The O2((1)Δg) quenching was faster in alkaline medium, favored by the ionization of the NSD phenolic group. Under Rf-photosensitization, NSD was degraded very much more rapidly than phenol, the latter being considered a paradigmatic water-contaminant model compound. NSD may behave as an antioxidant in bio-environments, as demonstrated employing the photooxidizable amino acid tryptophan as a relevant biological target., Discussion: The results indicate that a O2•−-mediated process is the main route for the Rf-sensitized photooxidation of NSD. Photodegradation of the biocide in the presence and absence of phenol and tryptophan was quantitatively evaluated, discussed, and interpreted in terms of competitive quenching processes of (3)Rf*, O2((1)Δg), and O2•− by the substrates.
- Published
- 2015
- Full Text
- View/download PDF
22. The employment of a removable chitosan-derivatized polymeric sensitizer in the photooxidation of polyhydroxylated water-pollutants.
- Author
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Ferrari GV, Andrada ME, Natera J, Muñoz VA, Paulina Montaña M, Gambetta C, Boiero ML, Montenegro MA, Massad WA, and García NA
- Subjects
- Hydroxylation, Oxidation-Reduction, Solubility, Chitosan chemistry, Photochemical Processes, Photosensitizing Agents chemistry, Polymers chemistry, Water Pollutants, Chemical chemistry
- Abstract
The known O2((1)∆g)-sensitizer system Chitosan bounded Rose Bengal (CH-RB), with Rose Bengal (RB) immobilized by irreversible covalent bonding to the polymer Chitosan (CH), soluble in aquous acidic medium, was employed in the photodegradation of three tri-hydroxy benzene water-contaminants (THBs). The system sensitizes the O2((1)∆g)-mediated photodegradation of THBs by a process kinetically favored, as compared to that employing free RB dissolved in the same solvent. Additionally the free xanthene dye, degradable by O2((1)∆g) through self-sensitization upon prolonged light-exposure, is considerably protected when bonded to CH-polymer. The polymeric sensitizer, totally insoluble in neutral medium, can be removed from the solution after the photodegradative cycle by precipitation through a simple pH change. This fact constitutes an interesting aspect in the context of photoremediation of confined polluted waters. In other words, the sensitizing system could be useful for avoiding to dissolve dyestuffs in the polluted waters, in order to act as conventional sunlight-absorbing dye-sensitizers. In parallel the interaction CH-O2((1)∆g) in acidic solution was evaluated. The polymer quenches the oxidative species with a rate constant 2.4 × 10(8) M(-1) s(-1) being the process mostly attributable to a physical interaction. This fact promotes the photoprotection of the bonded dye in the CH-RB polymer., (© 2014 The American Society of Photobiology.)
- Published
- 2014
- Full Text
- View/download PDF
23. On the natural fate of maleic hydrazide. Kinetic aspects of the photochemical and microbiological degradation of the herbicide.
- Author
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Pajares A, Bregliani M, Massad W, Natera J, Challier C, Boiero L, Montenegro M, and García NA
- Subjects
- Biodegradation, Environmental, Electrons, Environmental Pollutants chemistry, Environmental Pollutants isolation & purification, Environmental Pollutants metabolism, Herbicides isolation & purification, Humic Substances, Kinetics, Photosensitizing Agents chemistry, Reactive Oxygen Species chemistry, Riboflavin chemistry, Bacillus subtilis metabolism, Herbicides chemistry, Herbicides metabolism, Maleic Hydrazide chemistry, Photolysis, Pseudomonas aeruginosa metabolism
- Abstract
Kinetic and mechanistic aspects of the photochemical and microbiological degradation of the herbicide Maleic Hydrazide (MH) have been studied. Riboflavin (Rf, vitamin B2) was employed as a main photosensitizer whereas Humic Acid (HA) was included as a second sensitizer in order to more closely simulate natural environmental conditions. MH quenches excited singlet and triplet states of Rf, with rate constants close to the diffusion limit. The herbicide and dissolved molecular oxygen competitively quench triplet excited Rf. As a consequence the reactive oxygen species (ROS), superoxide radical anion (O2(-·)), hydrogen peroxide (H2O2) and singlet molecular oxygen (O2((1)Δg)) are produced by electron- and energy-transfer processes, respectively, as demonstrated by auxiliary experiments employing selective auxiliary quenchers and the exclusive O2((1)Δg) generator Rose Bengal (RB). As a global result, the photodegradation of Rf is retarded, whereas MH is degraded by the generated ROS. The bacteria Pseudomonas aeruginosa (Ps) and Bacillus subtilis (Bs), recognized as contaminants surface-water and soil and microbial antagonists of phytopathogenic, were used in the microbiological experiments. Results of the individual incubation of both bacteria in in the presence of MH indicate a stimulation on the Ps growth, implying the biodegradation of the herbicide, whereas MH only exerted a bacteriostatic effect on Bs., (Copyright © 2014 Elsevier B.V. All rights reserved.)
- Published
- 2014
- Full Text
- View/download PDF
24. The role of vitamin B6 as an antioxidant in the presence of vitamin B2-photogenerated reactive oxygen species. A kinetic and mechanistic study.
- Author
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Natera J, Massad W, and García NA
- Subjects
- Antioxidants metabolism, Antioxidants radiation effects, Hydrogen-Ion Concentration, Kinetics, Light, Muramidase metabolism, Oxidation-Reduction, Photolysis, Reactive Oxygen Species metabolism, Riboflavin metabolism, Riboflavin radiation effects, Vitamin B 6 metabolism, Vitamin B 6 radiation effects, Antioxidants chemistry, Reactive Oxygen Species chemistry, Riboflavin chemistry, Vitamin B 6 chemistry
- Abstract
We report on the photostability of a mixture of vitamins B6 and B2 (riboflavin, Rf) upon visible light irradiation and on the possible role of the vitamin B6 family (B6D) as deactivators of reactive oxygen species (ROS). The work is a systematic kinetic and mechanistic study under conditions in which only Rf absorbs photoirradiation. Pyridoxine, pyridoxal hydrochloride, pyridoxal phosphate and pyridoxamine dihydrochloride were studied as representative members of the vitamin B6 family. The visible light irradiation of dissolved Rf and B6D in pH 7.4 aqueous medium under aerobic conditions induces photoprocesses that mainly produce B6D degradation. The overall oxidative mechanism involves the participation of ROS. Photogenerated (3)Rf* is quenched either by oxygen, giving rise to O(2)((1)Δ(g)) by electronic energy transfer to dissolved ground state oxygen, or by B6D yielding, through an electron transfer process, the neutral radical RfH˙, and O(2)˙(-) in an subsequent step. B6D act as quenchers of O(2)((1)Δ(g)) and O(2)˙(-), the former in a totally reactive event that also inhibits Rf photoconsumption. The common chromophoric moiety of B6D represented by 3-hydroxypyridine, constitutes an excellent model that mimics the kinetic behavior of the vitamin as an antioxidant towards Rf-generated ROS. The protein lysozyme, taken as an O(2)((1)Δ(g))-mediated oxidizable biological target, is photoprotected by B6D from Rf-sensitized photodegradation through the quenching of electronically excited triplet state of the pigment, in a process that competes with O(2)((1)Δ(g)) generation.
- Published
- 2012
- Full Text
- View/download PDF
25. Vitamin B1 as a scavenger of reactive oxygen species photogenerated by vitamin B2.
- Author
-
Natera J, Massad WA, and García NA
- Subjects
- Gas Scavengers, Molecular Structure, Photolysis, Reactive Oxygen Species chemistry, Riboflavin chemistry, Thiamine chemistry
- Abstract
Kinetics and mechanism of photoprocesses generated by visible light-irradiation of the system riboflavin (Rf, vitamin B2) plus Thiamine (Th) and Thiamine pyrophosphate (ThDP), representing vitamin B1, was studied in pH 7 water. A weak dark complex vitamin B2-vitamin B1, with a mean value of 4 ± 0.4 M(-1) is formed. An intricate mechanism of competitive reactions operates upon photoirradiation, being the light only absorbed by Rf. Th and ThDP quench excited singlet and triplet states of Rf, with rate constants in the order of 10(9) and 10(6 ) M(-1 ) s(-1), respectively. With Vitamin B1 in a concentration similar to that of dissolved molecular oxygen in water, the quenching of triplet excited Rf by the latter is highly predominant, resulting in the generation of O(2)((1)Δ(g)). Superoxide radical anion was not detected under work conditions. A relatively slow O(2)((1)Δ(g))-mediated photodegradation of Th and ThDP was observed. Nevertheless, Th and especially ThDP behave as efficient physical deactivators of O(2)((1)Δ(g)). The thiazol structure in vitamin B1 appears as a good scavenger of this reactive oxygen species. This characteristic, that presents at vitamin B1 as a potential photoprotector of biological entities against O(2)((1)Δ(g)) attack, was been experimentally confirmed employing the protein lisozime as a photo-oxidizable target., (© 2010 The Authors. Photochemistry and Photobiology © 2010 The American Society of Photobiology.)
- Published
- 2011
- Full Text
- View/download PDF
26. Spirobifluorene-bridged donor/acceptor dye for organic dye-sensitized solar cells.
- Author
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Heredia D, Natera J, Gervaldo M, Otero L, Fungo F, Lin CY, and Wong KT
- Abstract
A new dye, SSD1, featuring two donor/acceptor chromophores aligned in a spiro configuration with two anchoring groups separated at a distance of 10.05 A (closely matching the distance between the adsorption sites of the anatase TiO(2) surface) undergoes efficient dye adherence on TiO(2) films. A dye-sensitized solar cell incorporating SSD1 exhibited a short-circuit current of 8.9 mA cm(-2), an open-circuit voltage of 0.63 V, a fill factor of 0.67, and a power conversion efficiency of 3.75%.
- Published
- 2010
- Full Text
- View/download PDF
27. [Audio-visual aids in the School of Dentistry of the University of the Andes].
- Author
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Guevara Zavala JA and Cova Natera JL
- Subjects
- Audiovisual Aids, Schools, Dental
- Published
- 1974
28. [Surgical treatment of the anterior epistaxis].
- Author
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Ortiz A and Natera J
- Subjects
- Adult, Child, Female, Humans, Methods, Epistaxis surgery, Nose surgery
- Published
- 1976
29. [Spherical alloys for amalgams].
- Author
-
Cova Natera JL
- Subjects
- Dental Amalgam
- Published
- 1972
30. [Audiovisual aids in the Faculty of Odontology of the University of the Andes].
- Author
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Guevara Zavala JA and Cova Natera JL
- Subjects
- Dental Materials, Schools, Dental, Venezuela, Audiovisual Aids, Education, Dental methods
- Published
- 1973
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