Benford´s Law with small sample sizes: A new exact test useful in health sciences during epidemics

Benford or “first digit” law has been used successfully to evaluate epidemiological surveillance systems, especially during epidemics. Conventional statistical methods for evaluation (x2 and log-likelihood ratio) are controversial when the number of data is small (n <7). In this methodological note a new test is proposed to evaluate compliance with Benford’s law with small samples, which can be used with biomedical, medical and public health data. Benford or “first digit” law has been used successfully to evaluate epidemiological surveillance systems, especially during epidemics. Conventional statistical methods for evaluation (x2 and log-likelihood ratio) are controversial when the number of data is small (n <7). In this methodological note a new test is proposed to evaluate compliance with Benford’s law with small samples, which can be used with biomedical, medical and public health data. La ley de Benford o de los “primeros dígitos” ha sido usada exitosamente para evaluar los sistemas de vigilancia epidemiológica, en especial durante epidemias. Los métodos estadísticos convencionales para la evaluación (x2 y razón de log-verosimilitud) son controversiales cuando los datos son poco (n<7). En esta nota metodológica se propone una nueva prueba para evaluar el cumplimiento de la ley de Benford con muestras pequeñas, que puede ser usada con datos de biomedicina, medicina y salud pública.&nbsp

Validation of an immunoassay for fast screening of bisphenol A in canned vegetables

The effects of BPA exposure on human health are an issue of concern and controversy. In the present work, the validation for the first time of a monoclonal antibody-based enzyme-linked immunoassay (ELISA) for BPA determination in canned vegetables is described, using HPLC as the reference method. From a collection of monoclonal antibodies, a high-sensitivity immunoassay was selected on the basis of its tolerance to organic solvents and the influence of matrix effects. This ELISA displayed a limit of detection of 3 µg kg−1of BPA in whole product of canned vegetables and 15 µg L−1 of BPA in the liquid portion. For assay validation, processed vegetables were fortified with BPA at 10, 50, and 200 µg kg−1. Sample treatment rendered crude and purified extracts. Purified extracts were analyzed by HPLC and ELISA, while crude extracts could be analyzed only by ELISA. Depending on the crop and the fortification level, good recoveries were obtained for both methods: 70.6-105 % for HPLC and 61.4-115 % (purified extracts) or 82-120 % (crude extracts) for ELISA. HPLC was more precise than ELISA. Finally, crude extracts of canned peas were analyzed by ELISA. Results (33−62 µg kg−1) also compared well with those obtained by HPLC on purified extracts (23−44 µg kg−1). In all samples, BPA concentration was significantly lower than the specific migration level of 600 µg kg−1 established by the European Commission. Therefore, the ELISA herein validated constitutes a sensitive, fast, and high-throughput technique for BPA screening in canned vegetables.The authors thank the Spanish Ministerio de Ciencia y Tecnologia for financial support (project AGL2006-13361) and Dr Miguel Gamon and David Romera for performing the HPLC analysis.Manclus Ciscar, JJ.; Moreno Tamarit, MJ.; Montoya Baides, Á. (2013). Validation of an immunoassay for fast screening of bisphenol A in canned vegetables. Analytical Methods. 5(16):4244-4251. https://doi.org/10.1039/c3ay40855hS42444251516Vandenberg, L. N., Hauser, R., Marcus, M., Olea, N., & Welshons, W. V. (2007). Human exposure to bisphenol A (BPA). Reproductive Toxicology, 24(2), 139-177. doi:10.1016/j.reprotox.2007.07.010Vom Saal, F. S., Akingbemi, B. T., Belcher, S. M., Birnbaum, L. S., Crain, D. A., Eriksen, M., … Zoeller, R. T. (2007). Chapel Hill bisphenol A expert panel consensus statement: Integration of mechanisms, effects in animals and potential to impact human health at current levels of exposure. Reproductive Toxicology, 24(2), 131-138. doi:10.1016/j.reprotox.2007.07.005Vandenberg, L. N., Chahoud, I., Heindel, J. J., Padmanabhan, V., Paumgartten, F. J. R., & Schoenfelder, G. (2010). Urinary, Circulating, and Tissue Biomonitoring Studies Indicate Widespread Exposure to Bisphenol A. Environmental Health Perspectives, 118(8), 1055-1070. doi:10.1289/ehp.0901716Vandenberg, L. N., Maffini, M. V., Sonnenschein, C., Rubin, B. S., & Soto, A. M. (2009). Bisphenol-A and the Great Divide: A Review of Controversies in the Field of Endocrine Disruption. Endocrine Reviews, 30(1), 75-95. doi:10.1210/er.2008-0021CAO, X.-L., CORRIVEAU, J., & POPOVIC, S. (2010). Bisphenol A in Canned Food Products from Canadian Markets. Journal of Food Protection, 73(6), 1085-1089. doi:10.4315/0362-028x-73.6.1085Schecter, A., Malik, N., Haffner, D., Smith, S., Harris, T. R., Paepke, O., & Birnbaum, L. (2010). Bisphenol A (BPA) in U.S. Food. Environmental Science & Technology, 44(24), 9425-9430. doi:10.1021/es102785dGarcía-Prieto, A., Lunar, L., Rubio, S., & Pérez-Bendito, D. (2008). Decanoic acid reverse micelle-based coacervates for the microextraction of bisphenol A from canned vegetables and fruits. Analytica Chimica Acta, 617(1-2), 51-58. doi:10.1016/j.aca.2008.01.061Ballesteros-Gómez, A., Rubio, S., & Pérez-Bendito, D. (2009). Analytical methods for the determination of bisphenol A in food. Journal of Chromatography A, 1216(3), 449-469. doi:10.1016/j.chroma.2008.06.037Yoshida, T., Horie, M., Hoshino, Y., Nakazawa, H., Horie, M., & Nakazawa, H. (2001). Determination of bisphenol A in canned vegetables and fruit by high performance liquid chromatography. Food Additives and Contaminants, 18(1), 69-75. doi:10.1080/026520301446412Brotons, J. A., Olea-Serrano, M. F., Villalobos, M., Pedraza, V., & Olea, N. (1995). Xenoestrogens released from lacquer coatings in food cans. Environmental Health Perspectives, 103(6), 608-612. doi:10.1289/ehp.95103608KODAIRA, T., KATO, I., LI, J., MOCHIZUKI, T., HOSHINO, M., USAKI, Y., … YANAIHARA, N. (2000). Novel ELISA for the Measurement of Immunoreactive Bisphenol A. Biomedical Research, 21(2), 117-121. doi:10.2220/biomedres.21.117Ohkuma, H., Abe, K., Ito, M., Kokado, A., Kambegawa, A., & Maeda, M. (2001). Development of a highly sensitive enzyme-linked immunosorbent assay for bisphenol A in serum. The Analyst, 127(1), 93-97. doi:10.1039/b103515kDe Meulenaer, B., Baert, K., Lanckriet, H., Van Hoed, V., & Huyghebaert, A. (2002). Development of an Enzyme-Linked Immunosorbent Assay for Bisphenol A Using Chicken Immunoglobulins. Journal of Agricultural and Food Chemistry, 50(19), 5273-5282. doi:10.1021/jf0202739Marchesini, G. R., Meulenberg, E., Haasnoot, W., & Irth, H. (2005). Biosensor immunoassays for the detection of bisphenol A. Analytica Chimica Acta, 528(1), 37-45. doi:10.1016/j.aca.2004.06.066Rahman, M. A., Shiddiky, M. J. A., Park, J.-S., & Shim, Y.-B. (2007). An impedimetric immunosensor for the label-free detection of bisphenol A. Biosensors and Bioelectronics, 22(11), 2464-2470. doi:10.1016/j.bios.2006.09.010Li, L., Wang, J., Zhou, S., & Zhao, M. (2008). Development and characterization of an immunoaffinity monolith for selective on-line extraction of bisphenol A from environmental water samples. Analytica Chimica Acta, 620(1-2), 1-7. doi:10.1016/j.aca.2008.05.036NISHII, S., SOYA, Y., MATSUI, K., ISHIBASHI, T., & KAWAMURA, Y. (2000). Down-Sizing in Analytical Chemistry. Determination of bisphenol A by ELISA using an organic solvent-resistant anti-bisphenol A monoclonal antibody. BUNSEKI KAGAKU, 49(12), 969-975. doi:10.2116/bunsekikagaku.49.969NISHI, K., TAKAI, M., MORIMUNE, K., & OHKAWA, H. (2003). Molecular and Immunochemical Characteristics of Monoclonal and Recombinant Antibodies Specific to Bisphenol A. Bioscience, Biotechnology, and Biochemistry, 67(6), 1358-1367. doi:10.1271/bbb.67.1358Ju, C., Xiong, Y., Gao, A., Yang, T., & Wang, L. (2011). Development of a Direct Competitive Enzyme-linked Immunosorbent Assay Using a Sensitive Monoclonal Antibody for Bisphenol A. Hybridoma, 30(1), 95-100. doi:10.1089/hyb.2010.0079Feng, Y., Ning, B., Su, P., Wang, H., Wang, C., Chen, F., & Gao, Z. (2009). An immunoassay for bisphenol A based on direct hapten conjugation to the polystyrene surface of microtiter plates. Talanta, 80(2), 803-808. doi:10.1016/j.talanta.2009.07.070Braunrath, R., Podlipna, D., Padlesak, S., & Cichna-Markl, M. (2005). Determination of Bisphenol A in Canned Foods by Immunoaffinity Chromatography, HPLC, and Fluorescence Detection. Journal of Agricultural and Food Chemistry, 53(23), 8911-8917. doi:10.1021/jf051525jInui, H., Takehara, A., Doi, F., Nishi, K., Takai, M., Miyake, S., & Ohkawa, H. (2009). A scFv Antibody-Based Immunoaffinity Chromatography Column for Clean-Up of Bisphenol A-Contaminated Water Samples. Journal of Agricultural and Food Chemistry, 57(2), 353-358. doi:10.1021/jf802781tLu, Y., Peterson, J. R., Gooding, J. J., & Lee, N. A. (2012). Development of sensitive direct and indirect enzyme-linked immunosorbent assays (ELISAs) for monitoring bisphenol-A in canned foods and beverages. Analytical and Bioanalytical Chemistry, 403(6), 1607-1618. doi:10.1007/s00216-012-5969-8Negre, M., Monterumici, C. M., Vindrola, D., & Piccone, G. (2011). Changes in chemical and biological parameters during co-composting of anaerobically digested sewage sludges with lignocellulosic material. Journal of Environmental Science and Health, Part A, 46(5), 509-517. doi:10.1080/10934529.2011.551737Manclus, J. J., Primo, J., & Montoya, A. (1994). Development of a Chlorpyrifos Immunoassay Using Antibodies Obtained from a Simple Hapten Design. Journal of Agricultural and Food Chemistry, 42(6), 1257-1260. doi:10.1021/jf00042a00

Elaboración de un plan de mejoramiento continuo a través de conceptos y herramientas administrativas para In The Club café internet

Las organizaciones en la actualidad, viven en una actividad de mercado, bastante cambiante, compleja y que exige competitividad; no desde el punto de vista de “acabar con el otro”, sino desde la perspectiva de abrirse nuevos mercados o nichos de mercado1, donde se compita desde la creatividad y desde factores diferenciadores. Es de este modo como las empresas en Colombia, sin distinción de su tamaño o actividad comercial, para lograr un nivel de competitividad, por lo menos a nivel local o nacional, requieren adaptarse al cambio y a las exigencias de su entorno, ya sea mediante transformaciones internas, haciendo referencia a su estructura administrativa, practicas, métodos y demás factores intrínsecos de la organización; o refiriéndose a mejoras externas como lo es el crecimiento en infraestructura, las mejoras físicas, mejoras en equipos y maquinaria, la implementación de nuevos servicios, las alianzas estratégicas; entre otras. Considerándose lo anterior, en el presente proyecto se encontrará la información como antecedentes históricos y conceptualización, que se requiere conocer para que un negocio, como lo es el café internet en la actualidad, se pueda plantear formas para mejorar su competitividad en el mercado; además como apoyo a esta investigación se encontrará un anexo de plan de negocios, que puede servir como herramienta para mejorar la satisfacción de clientes tanto actuales como potenciales para esta organización.Corporación Universitaria Minuto de Dio

Elaboración de un programa de mantenimiento preventivo para una máquina bordadora automática computarizada de la empresa BORDADOS NICARAGUA en la ciudad de Estelí.

Este trabajo consiste en la elaboración de un programa de mantenimiento preventivo en la empresa Bordados Nicaragua de la ciudad de Estelí, aplicado a una máquina bordadora automática computarizada. Para la elaboración del programa de mantenimiento se procedió de la siguiente manera: Se realizó un diagnóstico o evaluación del mantenimiento que la empresa brinda a la maquinaria. Se estudió las partes y funcionamiento de la máquina con ayuda de manuales e indicaciones facilitados por la empresa. Se recopiló la información necesaria para dar forma al trabajo. Según la información recolectada se procedió a la elaboración del programa de mantenimiento. Producto de la investigación se determinó la necesidad de la creación de un programa de mantenimiento preventivo en la empresa para garantizar beneficios en la vida útil de la máquina, la calidad del producto y disminución de los costos de mantenimiento

Analysis of Research Topics and Scientific Collaborations in Energy Saving Using Bibliometric Techniques and Community Detection

Concern about everything related to energy is increasingly latent in the world and therefore the use of energy saving concepts has been increasing over the past several years. The interest in the subject has allowed a conceptual evolution in the scientific community regarding the understanding of the adequate use of energy. The objective of this work is to determine the contribution made by international institutions to the specialized publications in the area of energy-saving from 1939 to 2018, using Scopus Database API Interface. The methodology followed in this research was to perform a bibliometric analysis of the whole scientific production indexed in Scopus. The world’s scientific production has been analysed in the following domains: First the trend over time, types of publications and countries, second, the main subjects and keywords, third, main institutions and their main topics, and fourth, the main journals and proceedings that publish on this topic. Then, these data are presented using community detection algorithms and graph visualization software. With these techniques, it is possible to determine the main areas of research activity as well as to identify the structures of the collaboration network in the field of renewable energy. The results of the work show that the literature in this field have substantially increased during the last 10 years

Análisis bioinformático y predicción de genes en secuencias genómicas de clostridium sp. ibun22a

Este trabajo tuvo como propósito identificar secuencias de genes en clones obtenidos en una librería genómica de la cepa colombiana de Clostridium sp. IBUN 22A. Los insertos de nueve clones con tamaæos superiores a 500 pb fueron secuenciados y analizados por medio de bÅ“squedas de los insertos completos o de sus marcos abiertos de lectura (ORFs) traducidos en GenBank 141.0 y Uniprot 6.6 con BLAST 2.2.8. Se identificaron seis genes con alta similaridad a genes de metabolismo bÆsico (housekeeping) en diferentes especies de Clostridium. En el clon pBsIBUN22A-1 se localizó una secuencia de 851 pb con una identidad del 99.74% respecto al gen codificante de la enzima glicerol deshidratasa (DhaBl) de Clostridium butyricum (AY968605) involucrada en la producción de 1,3 Propanodiol (1,3-PD). La identifica­ción de genes presentes en la cepa nativa Clostridium IBUN 22A abre la puerta a la investigación básica y a la ingeniería metabólica para hacer más rentable el proceso de producción de 1,3-PD junto al conocimiento de los genes presentes en la cepa nativa. Palabras clave: análisis de secuencias, librería genómica, Clostridium, glicerol deshidratasa, 1,3-propanodiol.This work was aimed at identifying gene sequences in recombinant clones obtained from a genomic library from the Colombian Clostridium sp. IBUN 22A native strain. Nine clones greater than 500 bp were sequenced and analysed using BLAST 2.2.8 to search for complete inserts or their translated open reading frames (ORFs) in GenBank 141.0 and Uniprot 6.6. Seven genes having high similarity to housekeeping genes from different Clostridium species were identified. An 851 bp sequence was located in the pBsIBUN22A-1 clone, having 99.74% identity with the gene encoding the Clostridium butyricum enzyme glycerol dehydratase (DhaBl) which is involved in 1,3-propanediol (1,3-PD) production. Identifying genes in the native IBUN 22A strain formed the starting point for basic research and metabolic engineering aimed at making 1,3-PD production more profitable and increasing knowledge of genes present in the native strain. Key words: glycerol dehydratase, 1,3-propanediol, genomic library, Clostridium, sequence analysis

Modifying RANKL/OPG mRNA expression in differentiating and growing human primary osteoblasts

The OPG / RANKL system in primary cultures of human osteoblasts has been studied by di ff erent authors. However, very few studies have been performed on gene expression of RANKL and OPG at di ff erent stages of maturation on human osteoblast cultures.The e ff ect of 17-estradiol and 1,25dihydroxyvitamin D3 on the OPG / RANKL system is not known during the di ff erent states of cellular maturation. In this work we quantifi ed OPG and RANKL protein levels (ELISA) and the mRNA of OPG, RANKL, collagen type I, alkaline phosphatase, and osteocalcin (semi-quantita-tive RT-PCR) in human osteoblasts. We analyzed these in basal conditions and after incubation with 17- -estradiol and 1,25dihydroxyvitamin D3 in the first and second phases. We found that OPG secretion and expression levels increased throughout cellular growth.RANKL proteins were detected only in the first stage, and the expression increased throughout the first phase. Thus, the RANKL / OPG ratio was higher in immature osteoblasts than in mature osteoblasts. The evolution of RANKL gene expression was related to collagen I and alkaline phosphatase, while OPG was related to osteocalcin. We observed no modi fi cations after estradiol and 1,25dihydroxyvitamin D3 treatment. Our results suggest that the OB is a positive stimulator at precocious stages of diff erentiation on osteoclastogenic modulates