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New approach to assess sperm DNA fragmentation dynamics： Fine-tuning mathematical models

Journal of Animal Science and Biotechnology 2017年第3期8卷 592-600页

作者： Isabel Ortiz jesus dorado Jane Morrell Jaime Gosalvez Francisco Crespo Juan M.Jimenez Manuel Hidalgo Veterinary Reproduction Group Department of Animal Medicine and Surgery Faculty of Veterinary Medicine University of Cordoba 14071 Cordoba Spain Department of Clinical Sciences Division of Reproduction Swedish University of Agricultural Sciences Box 7054 SE-75007 Uppsala Sweden Department of Biology Universidad Aut6noma de Madrid 28049 Madrid Spain Department of Reproduction Centro Militar de Cria Caballar (FESCCR-Ministry of Defense) 05005 Avila Spain Department of Chemistry and Physics of Materials University of Salzburg Hellbrunner StraBe 34/111 A-5020 Salzburg Austria

Background： Sperm DNA fragmentation（sDF） has been proved to be an important parameter in order to predict in vitro the potential fertility of a semen sample. Colloid centrifugation could be a suitable technique to select those donkey sperm more resistant to DNA fragmentation after thawing. Previous studies have shown that to elucidate the latent damage of the DNA molecule, sDF should be assessed dynamically, where the rate of fragmentation between treatments indicates how resistant the DNA is to iatrogenic damage. The rate of fragmentation is calculated using the slope of a linear regression equation. However, it has not been studied if s DF dynamics fit this model. The objectives of this study were to evaluate the effect of different after-thawing centrifugation protocols on sperm DNA fragmentation and elucidate the most accurate mathematical model（linear regression, exponential or polynomial） for DNA fragmentation over time in frozen-thawed donkey ***： After submitting post-thaw semen samples to no centrifugation（UDC）, sperm washing（SW） or single layer centrifugation（SLC） protocols, sD F values after 6 h of incubation were significantly lower in SLC samples than in SW or *** of determination（R-2） values were significantly higher for a second order polynomial model than for linear or exponential. The highest values for acceleration of fragmentation（aSDF） were obtained for SW, fol owed by SLC and ***： SLC after thawing seems to preserve longer DNA longevity in comparison to UDC and SW. Moreover,the fine-tuning of models has shown that sDF dynamics in frozen-thawed donkey semen fit a second order polynomial model, which implies that fragmentation rate is not constant and fragmentation acceleration must be taken into account to elucidate hidden damage in the DNA molecule.

关键词： Colloid centrifugation Dynamics Fine-tuning Mathematical models Sperm DNA fragmentation

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Robust Soil Quality Index for Tropical Soils Influenced by Agricultural Activities

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Journal of Agricultural Chemistry and Environment 2017年第4期6卷 199-221页

作者： jesus Gabriel Rangel-Peraza Edith Padilla-Gasca Rosalía López-Corrales Jaime Rochín Medina Yaneth Bustos-Terrones Leonel Ernesto Amabilis-Sosa Abraham Efraim Rodríguez-Mata Tomás Osuna-Enciso Instituto Tecnológico de Culiacán Departamento de Ing Ambiental Juan de Dios Batiz 310 Col. Guadalupe Culiacán Mexico CONACYT-Instituto Tecnológico de Culiacán Juan de Dios Bátiz 310. Col. Guadalupe P.C. 80220 Culiacán Sinaloa México Centro de Investigación en Alimentación y Desarrollo A. C. Carretera Culiacán-El Dorado Km. 5.5 C.P. 80129 Culiacán México

The knowledge of the soil quality plays a vital role in the agricultural sector. Despite its importance, there is scarce scientific information concerning this regard. The objective of this research is to develop a methodology to identify and select the most appropriate indicators of Soil Quality Index (SQI) in a region with high agricultural activity. For its conformation, a descriptive statistical analysis and a Pearson correlation matrix were performed and the indicators that showed greater variation were identified using a Principal Components Analysis (PCA). A sensitivity analysis was carried out and the most sensible soil indicators of?SQI?were identified. This statistical procedure was also used to specify the weights of the indicators in?SQI. The variables resulting from the multiparametric statistical analysis were pH, organic matter, sodium, calcium, iron, zinc, cation exchange capacity and electrical conductivity. The robustness of the?SQI?obtained in this study was demonstrated through simulations carried out by the numerical optimization through simplex method. The Soil Quality Index range obtained (0.54 - 0.75) locates Culiacan Valley soils as moderate/high quality.

关键词： Principal Components Analysis Soil Quality Index Pearson Correlation Soil Quality Indicators Sensitivity Analysis

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