2,125 research outputs found

    On-Line Team Project Communication Tool Set

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    Team projects offer a valuable mechanism for effective learning. However, communication within the team, with the instructor and between different teams is a challenging task that can greatly limit the effectiveness of the learning experience. Some of the tools and concepts that are being developed for distance learning applications can be used to enhance team project communication within teams that are geographically separated as well as for in-campus teams. This article documents a set of on-line tools that allow for asynchronous team participation and timely monitoring and feedback by the instructor

    Induction of Somatic Embryos in Cultured Leaf Explants of Coffea Arabica

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    Sari. Tulisan ini menguraikan induksi embrio somatik dan pertumbuhan planlet yang dihasilkan dari kultur jaringan daun Coffea arabica. Untuk pembentukan kalus, potongan jaringan daun ditanam pada medium Linsmaier dan Skoog dengan 3% sukrosa ditambah berbagai konsentrasi 2,4-asam diklorofenoksi asetat atau asam naftalen asetat dan kinetin. Delapan belas minggu setelah penanaman, kalus akan dibentuk pada medium Linsmaier dan Skoog dengan 2 pM 2,4-asam diklorofenoksi asetat dan 5-7 pM kinetin dan juga pada medium dengan 0,05 pM asam naftalen asetat dan 6-8 pM kinetin. Pembentukan embrio somatic diperoleh dengan pemotongan kalus pada medium padat Linsmaier dan Skoog dengan 3 pM sampai 35 pM kinetin dan 0,05 pM asam indole butirat dan juga dalam medium cair Gamborg, Miller, dan Ojima yang diberi 0,05 pM sampai 2,5 pM 2,4-asam diklorofenoksi asetat. Abstract. Somatic embryo induction and subsequent plantlets development in culture of Coffea arabica leaf tissue explants was described. For callus formation leaf segments were grown on medium Linsmaier and Skoog with 3% sucrose and varying concentrations of 2,4-Dichlorophenoxyaceticacid or Naphthalene Acetic Acid and Kinetin. Eighteen weeks after inoculation, callus will be formed on Linsmaier and Skoog's medium with 2 μM 2,4-Dichlorophenoxyacetic acid and 5-7 μM Kinetin and also on medium with 0.05 μM Naphtalene Acetic Acid and 6-8 μM Kinetin. Somatic embryos are then formed by inoculation of calli segments on medium Linsmaier & Skoog with 3 μM to 35 μM Kinetin and 0.05 μM Indole Butyric Acid. Somatic embryos are also formed in liquid medium of Gamborg, Miller and Ojima supplemented with 0.05 μM to 2.5 μM 2,4-Dichlorophenoxyacetic acid

    Supercritical antisolvent particle precipitation and fractionation of rosemary (Rosmarinus officinalis L.) extracts

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    The simultaneous fractionation and precipitation of an ethanolic extract of rosemary (Rosmarinus officinalis L.) using supercritical carbon dioxide anti-solvent technique was studied, with the target of separate in two different fractions the key antioxidants of rosemary (i.e. rosmarinic acid, carnosic acid and carnosol). The effect of pressure and temperature on the fractionation process was investigated, together with the morphology and particle size distribution of the precipitates. Additionally, the chemical composition of the oleoresins were analyzed and reported. In the range of pressures (9-20 MPa) and temperatures (313-333 K) used in this work, the precipitates presented a 2-3 fold enrichment of rosmarinic acid, while carnosic acid and carnosol were concentrated (2-3 fold enrichment) in the oleoresin fractions. Furthermore, in general, oleoresins presented higher antioxidant activity than precipitates. Particles produced with a nozzle of diameter 101.6 μm were smaller and more spherical with increasing pressure (mean value 4-10 μm at 20 MPa) and decreasing temperatureThe authors gratefully acknowledge the financial support from Ministerio de Economía y Competitividad of Spain (Proyect AGL2016- 76736-C3-1-R). Somaris E. Quintana is grateful for the funding provided by Gobernación de Bolivar and Fundación Ceiba, Colombia, in the project “Bolívar Gana con Cienci

    Preparation and characterization of licorice‐chitosan coatings for postharvest treatment of fresh strawberries

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    Several plant extracts are being investigated to produce edible coatings, mainly due to their antioxidant and antimicrobial activities. In this study, licorice root extracts were produced by ultrasound‐assisted extraction and were combined with chitosan to elaborate edible coatings. Different solvents and temperatures were used in the extraction process, and the antioxidant and antimicrobial activity of the extracts were assessed. The most bioactive extracts were selected for the development of the edible coatings. The rheological properties of the coatings were studied, and they were applied on strawberry to evaluate their physicochemical and microbiological properties. The addition of licorice extract to chitosan resulted in positive effects on the rheological properties of the coatings: the incorporation of phytochemicals to chitosan decreased the shear stress and improved the restructuring ability of the coating solutions. The films presented a reduction of the Burger model parameter, indicating a reduction of rigidity. Furthermore, the strawberry coated with chitosan and licorice extract maintained good quality parameters during storage and showed the best microbiological preservation in comparison with controls. Hence, the use of chitosan with licorice extract is a potential strategy to produce edible coating for improving the postharvest quality of fruitsThis research was funded by Comunidad Autónoma de Madrid, grant number P2013/ABI27, project Bolívar Gana con Ciencia, MinCiencias Contract 368-2019 and Programa Nacional de Innovación Agraria—PNIA of Perú, Contract: No. 152-2018-INIA-PNIA-PASANTI

    Fractionation and precipitation of licorice (Glycyrrhiza glabra L.) phytochemicals by supercritical antisolvent (SAS) technique

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    Supercritical anti-solvent precipitation (SAS) using carbon dioxide is a novel technique that can be used to produce powdered ingredients in small size particles, facilitating their incorporation into food matrices. In this work, the SAS precipitation of a licorice root ethanolic extract was studied. SAS assays were carried out at 15–20 MPa, 308.15 and 313.15 K, and two different concentrations (9.6 and 14.2 mg/ml) of the ethanolic licorice extract. In the range of conditions investigated, SAS pressure and temperature did not affect significantly the precipitation yield, but phytochemicals recovery was higher with the lower licorice extract concentration. Moreover, the fractionation of licorice bioactives (liquiritin, liquiritigenin, isoliquiritigenin, glabridin and glycyrrhizic acid) was assessed, together with the content of total phenolic compounds and antioxidant activity of the powders and oleoresin by-products obtained. In this respect, precipitates and oleoresins presented significant differences in the concentration of some licorice bioactives, and higher antioxidant activity was observed in precipitates. Additionally, significant effect of pressure, temperature and licorice extract concentration on the morphology and particle size of precipitates was observed, recovering smaller and more regular particles at 15–20 MPa, 313.15 K and 9.6 mg/ml licorice extract concentration, attaining satisfactory yield and antioxidant activityThe authors gratefully acknowledge the financial support from Ministerio de Economía y Competitividad of Spain (Projects AGL2017-89055-R and AGL2016-76736-C3-1-R). Somaris E. Quintana is grateful for the funding provided by Gobernación de Bolivar and Fundación Ceiba, Colombia, in the project “Bolívar Gana con Ciencia

    Potensi Tunikata Rhopalaea SP. sebagai Sumber Inokulum Jamur Simbion Penghasil Antimikroba

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    The research on the potency of tunicate Rhopalaea sp as a source of inoculum fungal symbionts that produce antimicrobial has been done. This research aimed to know the tunicate's potency as a source of inoculum fungal symbionts and to characterize isolate symbiont fungal Rhopalaea sp. Isolation of fungi was performed using a PDA medium (Potato Dextrose Agar). Characterization of isolates fungal symbiont through macroscopic and microscopic observation, and testing its activity against pathogenic bacteria and fungi. The results showed there were three isolates(Asc 1, Asc 2 dan Asc 3) of fungal symbionts Rhopalaea sp. The results of macroscopic observation colony showed that Asc 1 had a flat surface such as cotton while Asc 2 and Asc 3 had a surface such as flour; Colours of isolates : Asc 1 (yellow), Asc 2 and Asc 3 (dark green). The result of microscopic observation reveals that Asc 1 had septa, Asc 2 and Asc 3 hadn't septa; Asc 1 with blue brownish hyphae, while Asc 2 and Asc 3 hyaline (colorless); Asc 1 had asexual spores sporangiophores, while Asc 2 and Asc 3 had conidioshpore. Asc 1 isolate was suspected, belongs to the genus Penicillium and Asc 2 and Asc 3 isolates were suspected to be classified into the genus Aspergillus. All three isolates were able to inhibit the growth of Salmonella thypi bacteria and Candida albicans fungus

    Antioxidant and antimicrobial assessment of licorice supercritical extracts

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    Licorice (Glycyrrhiza glabra L.) is a plant used widely in herbal medicines due to their several biological potentials. The supercritical extraction of licorice roots was investigated to assess the antioxidant and antimicrobial activity of the extracts. Extraction conditions were pressures from 15 to 40 MPa, 313.15 and 333.15 K, and ethanol cosolvent in the range of 0 to 20% mass. In the case of high-pressure extractions using pure carbon dioxide (CO2) fractionation of the supercritical extract was accomplished in a two-cell decompression system. Fractionation was carried out with the aim to examine the potential separation of the antioxidant and antimicrobial licorice compounds and thus increase the bioactive properties of the fractions obtained in each separation cell. Main licorice bioactive compounds, liquiritin, liquiritigenin, glycyrrhizin, isoliquiritigenin and glabridin, were identified by HPLC and quantified using standards. Extracts obtained with supercritical CO2 and ethanol cosolvent contain the higher amounts of phenolic compounds and also the higher antioxidant activity but exhibit low or even no antimicrobial activity. Using pure CO2 at high pressure coupled with the on-line fractionation of the extract, two samples were obtained which showed, respectively, lower phenolic compounds content and good antimicrobial capacity (first fraction) and higher phenolic compounds content and antioxidant capacity (second fraction). Thus, the advantages of supercritical on-line fractionation are demonstrated in the extraction of Licorice rootsThe authors gratefully acknowledge the financial support from Ministerio de Economía y Competitividad of Spain (Projects AGL2016-76736-C3-1-R and AGL2015-64522-C2-R

    Estudio comparativo de fármacos antidiabéticos orales. – III. Actividad antihiperglucemiante frente a la sobrecarga endovenosa de glucosa

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    En el presente trabajo se compara la actividad antihiperglucemiante frente a sobrecarga endovenosa de glucosa, de los treinta y dos antidiabéticos orales comercializados en nuestro país; empleándose conejos como animal de experimentación. Se ha realizado el estudio con dosis diferentes y administrando el fármaco antes de la sobrecarga de glucosa, así como simultáneamente a ella.The antihiperglucemic activity of the thirty two oral antidiabetic comercialized in Spain toward an endovenous overdose of glucose has been studied and compared, using rabbits as experimentation animals. The study has been carried out using two different doses and administering the drug either before the overdose of glucose or simultaneously with it

    Inspección de subestaciones eléctricas: YOLOv5 en la identificación de puntos calientes mediante imágenes térmicas

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    Substations are key facilities within an electrical system, untimely failures tend to cause low quality and negative effects on the electrical supply. An early indicator of potential electrical equipment failure is the appearance of hot spots; therefore, its detection and subsequent programmed correction avoids incurring in major failures and unnecessary operation stops. In this research, 64 experiments of the YOLOv5 algorithm were carried out, with the purpose of proposing an automated computer vision mechanism for the detection of hot spots in thermal images of electrical substations. The best results show a mAP value of 81.99%, which were obtained with the YOLOv5m algorithm and the transfer learning application. These results leave a basis to deepen and improve the performance of the algorithm by varying other hyperparameters to those considered in this study.Las subestaciones son instalaciones clave dentro de un sistema eléctrico; las fallas intempestivas tienden a causar baja calidad y efectos negativos del suministro eléctrico. Un indicador temprano de posibles fallas en los equipos eléctricos es la aparición de puntos calientes; por lo que su detección y posterior corrección programada evita incurrir en fallas mayores y paradas de operación innecesarias. En esta investigación se realizaron 64 experimentos del algoritmo YOLOv5, con la finalidad de proponer un mecanismo automatizado de visión por computadora para la detección de puntos calientes en imágenes térmicas de subestaciones eléctricas. Los mejores resultados muestran un valor mAP de 81,99 %, los cuales se obtuvieron con el algoritmo YOLOv5m y la aplicación de transfer learning. Estos resultados dejan una base para profundizar y mejorar el desempeño del algoritmo, variando otros hiperparámetros a los considerados en el presente estudio

    Biogas production from the specialized dairy farming and porcine subsectors in Antioquia, Colombia: theoretical and technical-energy potential approach

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    Received: February 23rd, 2022 ; Accepted: May 1st, 2022 ; Published: May 11th, 2022 ; Correspondence: [email protected] developing countries, residual biomass usage by means of anaerobic digestion offers several benefits and opportunities, such as a sustainable energy source, production of organic fertilizers and new agrobusiness models. In Latin America, Colombia is one of the most promising markets for the implementation of this technology in terms of availability of biomass and economic growth, as recently reported by local government organizations. In this paper, special attention is given to Antioquia, a department of Colombia with the largest farms of cattle and pigs, according to information reported in 2018 by the Ministry of Agriculture and Rural Development. It is estimated that manure from the porcine subsector in Antioquia has an approximate technical-energy potential of 1,896 TJ year-1 , varying from 1,611 to 2,186 TJ year-1 , corresponding to the 95% confidence interval. In the case of manure generated by the livestock subsector in Antioquia, it is estimated a theoretical energy potential of 8,566 TJ year-1 . However, traditional extensive production systems disseminate manure through the pastures turning centralization of the available residual biomass a difficult task and not senseful. Based on the local practices of the specialized dairy subsector, it is estimated that manure collected during the milking process could reached up to 25% of the total available. Biochemical conversion of this amount of biomass has an estimated technical-energy potential of 187 TJ year-1 , varying from 156 and 236 TJ year-1 , corresponding to the 95% confidence. The aim of this article is to estimate the technical-energy potential for the livestock and porcine subsectors in the Department of Antioquia, based on the available residual biomass according to local farming practices
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