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1.
rev. udca actual. divulg. cient ; 23(2): e1375, jul.-dic. 2020. tab, graf
Artigo em Espanhol | LILACS-Express | LILACS | ID: biblio-1157037

RESUMO

RESUMEN Los sistemas de producción agrícolas en la subregión Valle del Sinú, en Colombia, en los últimos 50 años, se han basado en la siembra de cultivos en rotación o alternancia de maíz - algodón y arroz, y se caracterizan por el uso intensivo de implementos de mecanización e insumos agrícolas. El objetivo de este estudio fue evaluar las características fisicoquímicas de los suelos, bajo los sistemas productivos de maíz - algodón y arroz e identificar las principales limitantes de suelo, que afectan el desarrollo y la productividad de los cultivos, en la subregión Valle del Sinú. Para lo anterior, se realizaron muestreos de suelo en 64 sitios, distribuidos en cinco municipios del Valle del Sinú, evaluando propiedades físicas y químicas del suelo. El suelo en estudio pertenece al orden Inceptisol, moderadamente profundo, compuesto por arcillas expansivas y horizonte argílico. El suelo, se caracterizó por una reacción acida (5,82±0,87 a 6,78±0,34), contenido medio de MO. La media de la CIC varió en rango, de 18,45±2,94 a 22,85±4,36cmol(+) kg-1, la CE estuvo no salinos, variando de 0,29±0,09 a 0,91±1,70dS cm-1. Los contenidos de P, S, Ca, Mg y K fueron altos. La densidad aparente mostró valores promedios restrictivos para el desarrollo de raíces en cuatro de los cinco municipios, variando de 1,42±0,10 a 1,49±0,08g cm-3, excepto en San Carlos (1,33±0,14g cm-3). Los resultados obtenidos evidencian indicios de procesos de degradación de suelo, relacionados con el manejo de los suelos.


ABSTRACT The agricultural production systems in the Valle del Sinú subregion in Colombia, in the last 50 years, have been based on the sowing of crops in rotation and / or alternation of corn - cotton and rice, and are characterized by the intensive use of implements mechanization and agricultural inputs. The aim of this study was to evaluate the physicochemical characteristics of the soils under the corn - cotton and rice production systems and identifying the main soil limitations, which affect crop development and productivity, in the Sinú Valley Subregion. For the above, soil sampling was carried out at 64 sites distributed in five municipalities of the Sinú Valley, evaluating the physical and chemical properties of the soil. The soil under study belongs to the order Inceptisol, moderately deep, composed of expansive clays and argillic horizons. The soil was characterized by an acid reaction (5.82 ± 0.87 to 6.78 ± 0.34), average MO content. The mean of the CIC varied in the range of 18.45 ± 2.94 to 22.85 ± 4.36cmol(+) kg-1, the EC was not saline, varying from 0.29 ± 0.09 to 0.91 ± 1.70dS cm-1. The contents of P, S, Ca, Mg and K were high. The apparent density showed restrictive average values for root development in four of the five municipalities, ranging from 1.42 ± 0.10 to 1.49 ± 0.08g cm-3, except in San Carlos (1.33 ± 0.14g cm-3). The results obtained show evidence of soil degradation processes related to soil management.

2.
J Oral Maxillofac Surg ; 62(12): 1517-23, 2004 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-15573352

RESUMO

PURPOSE: The goal of the study was to design and test prototypes for a new, internal resorbable Le Fort III distractor in the minipig model. MATERIALS AND METHODS: Le Fort III osteotomies were performed on 3 juvenile minipigs, followed by implantation of the bioabsorbable distractors. After a 5-day latency period, the distraction progressed at a rate of 1 mm/day in 2 equal increments for 12 days. This was followed by a 6-week consolidation phase. Cephalometric radiographs were taken postoperatively, on completion of distraction and after the consolidation phase, to evaluate the amount of distraction that was obtained. Necropsy was performed at the completion of each experiment. RESULTS: The first minipig was sacrificed at the end of the distraction period because of device failure. On necropsy, it was noted that the anterior footplate on either side had failed. The second minipig was sacrificed during the latency period because of severe pneumonia. On necropsy, it was noted that none of the footplates had failed but that the distraction barrels on either side had become dislodged from the anterior bioabsorbable footplates. The third minipig was sacrificed at the end of the distraction period because of device failure. On necropsy, it was noted that the posterior bioabsorbable footplates on either side were fractured across the posterior screw lines. CONCLUSIONS: The bioabsorbable devices evaluated in this study could not withstand the forces generated during distraction osteogenesis in the minipig model. Experience with the prototypes may help in designing internal bioresorbable Le Fort III distraction devices.


Assuntos
Implantes Absorvíveis , Fixadores Internos , Maxila/cirurgia , Osteogênese por Distração/instrumentação , Osteotomia de Le Fort/instrumentação , Animais , Materiais Biocompatíveis , Placas Ósseas , Parafusos Ósseos , Desenho de Equipamento , Falha de Equipamento , Teste de Materiais , Osteotomia de Le Fort/classificação , Projetos Piloto , Suínos , Porco Miniatura
3.
Nucleic Acids Res ; 30(22): 4892-901, 2002 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-12433992

RESUMO

We describe gene targeting experiments involving a human cell line (RAN10) containing, in addition to its endogenous alleles, two ectopic alleles of the interferon-inducible gene 6-16. The frequency of gene targeting at one of the ectopic 6-16 alleles (H3.7) was 34-fold greater than the combined frequency of gene targeting involving endogenous 6-16 alleles in RAN10. Preference for H3.7 was maintained when the target loci in RAN10 were transcriptionally activated by interferon. Despite the 34-fold preference for H3.7, the absolute gene targeting efficiency in RAN10 was only 3-fold higher than in the parental HT1080 cell line. These data suggest that different alleles can compete with each other, and perhaps with non-homologous loci, in a step which is necessary, but not normally rate-limiting, for gene targeting. The efficiency of this step can therefore be more sensitive to chromosomal position effects than the rate-determining steps for gene targeting. The nature of the position effects involved remains unknown but does not correlate with transcription status, which in our system has a very modest influence on the frequency of gene targeting. In summary, our work unequivocally identifies a position effect on gene targeting in human cells.


Assuntos
Cromossomos Humanos , Marcação de Genes/métodos , Alelos , Células Clonais , Inibidores Enzimáticos/farmacologia , Inibidores de Histona Desacetilases , Humanos , Ácidos Hidroxâmicos/farmacologia , Interferons/farmacologia , Proteínas Mitocondriais , Poliploidia , Proteínas/genética , Transcrição Gênica , Células Tumorais Cultivadas , Regulação para Cima
4.
Nucleic Acids Res ; 30(3): 740-8, 2002 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-11809887

RESUMO

Overexpression of the RAD52 epistasis group of gene products is a convenient way to investigate their in vivo roles in homologous recombination (HR) and DNA repair. Overexpression has the further attraction that any associated stimulation of HR may facilitate gene-targeting applications. Rad51p or Rad52p overexpression in mammalian cells have previously been shown to enhance some forms of HR and resistance to ionising radiation, but the effects of Rad52p overexpression on gene targeting have not been tested. Here we show that Rad52p overexpression inhibits gene targeting while stimulating extrachromosomal HR. We also find that Rad52p overexpression affects cell-cycle distribution, impairs cell survival and is lost during extensive passaging. Therefore, we suggest that excess Rad52p can inhibit the essential RAD51-dependent pathways of HR most likely to be responsible for gene targeting, while at the same time stimulating the RAD51-independent pathway thought to be responsible for extrachromosomal HR. The data also argue against Rad52p overexpression as a means of promoting gene targeting, and highlight the limitations of using a single HR assay to assess the overall status of HR.


Assuntos
Cromossomos Humanos/genética , Proteínas de Ligação a DNA/metabolismo , Marcação de Genes , Recombinação Genética/genética , Homologia de Sequência do Ácido Nucleico , Western Blotting , Ciclo Celular , Núcleo Celular/metabolismo , Sobrevivência Celular , Reparo do DNA/genética , Proteínas de Ligação a DNA/genética , Epistasia Genética , Imunofluorescência , Humanos , Hipoxantina Fosforribosiltransferase/genética , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Fenótipo , Rad51 Recombinase , Proteína Rad52 de Recombinação e Reparo de DNA , Transfecção , Células Tumorais Cultivadas
5.
Rev. chil. pediatr ; 57(6): 510-3, nov.-dic. 1986. ilus
Artigo em Espanhol | LILACS | ID: lil-40092

RESUMO

Se examinaron 69 pacientes con síndrome de Down de población escolar chilena y 68 pacientes con retardo mental no asociado con síndrome de Down, los que constituyeron el grupo control. Con el objeto de determinar las anomalías existentes en cuanto a salud oral en los enfermos con síndrome de Down, en ambos grupos se analizó estado de la mucosa en ambos maxilares, configuración palatina, presencia o ausencia de torus, tipo dentición, presencia de caries, piezas dentarias fusionadas, anomalías de posición, ausencia de piezas dentarias, alterción del desarrollo mandibular, características linguales y frecuencia de cepillado. Los resultados obtenidos indican que existen importantes diferencias en los parámetros estudiados, con respecto a lo indicado en la literatura en pacientes con síndrome de Down de origen étnico diferente. Las anomalías dentarias de posición y el prognatismo son significativamente más frecuentes en pacientes con síndrome de Down que en niños con retardo mental de otras causas: 59,42% vs 32,35%,p=0,001 y 39,21%vs5,64%, p=0,001 respectivamente


Assuntos
Criança , Humanos , Masculino , Feminino , Anormalidades Dentárias/complicações , Síndrome de Down/complicações , Anormalidades Dentárias/diagnóstico , Deficiência Intelectual/complicações
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