1,165 research outputs found

    ACLIMATACIÓN DE HÍBRIDOS INTRAESPECÍFICOS DE Vanilla planifolia Jacks. ex Andrews, OBTENIDOS in vitro

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    Vitroplants were developed of intra-specific hybrid genotypes from Vanilla planifolia Jacks. ex Andrews obtained by seed, since these do not germinate naturally for lack of nutritional reserves. To ensure the longest survival, two techniques for pre-acclimation were evaluated, and one for acclimation, using 21 intra-specific crosses and one self-fertilization. Vitroplants had 4-7 cm of length and three roots. They were placed in one-liter plastic recipients with Peat moss® substrate with the following treatments: T1 one plastic cup used as tap for the container, T2 one transparent nylon bag as lid, and in both casesfive plants per cross. Both treatments were taken to the germination chamber at 26 °C and 70 % relative humidity. At 53 days after pre-acclimation they were taken to a module of shade mesh (80 %) for acclimation. Significant differences were found (P?0.05) between pre-acclimation treatments, finding T2 with better percentages of vitroplant survival, because the technique allowed a gradual change from in vitro conditions to ex vitro conditions. During the acclimation phase, significant statistical differences were also observed between the crosses (P?0.05) due to their genetic conditionSe desarrollaron vitroplantas de genotipos híbridos intraespecíficos de Vanilla planifolia Jacks. ex Andrews obtenidos por semilla, ya que éstas no germinan de manera natural por falta de reservas nutritivas. Para asegurar la mayor sobrevivencia se evaluaron dos técnicas de preaclimatación y una de aclimatación utilizando 21 cruzas intraespecificas y una autofecundación. Las vitroplantas tuvieron 4-7 cm de longitud y tres raíces. Se colocaron en recipientes de plásticode un litro con sustrato Peat moss® con los tratamientos: T1 un vaso de plástico usado como tapa del frasco, T2 una bolsa de nylon transparente como tapa, y en ambos casos cinco plantas por cruza. Ambos tratamientos se llevaron a cámara de germinación a 26 °C y 70% de humedad relativa. A los 53 días después de la preaclimatación se llevaron a un módulo de malla sombra (80%) para su aclimatación. Existieron diferencias significativas (P?0.05) entre tratamientos de preaclimatación, registrando T2 con mejores porcentajes de sobrevivencia de vitroplantas, debido que la técnica permitió un cambio gradual de las condiciones in vitro a las condiciones ex vitro. En la fase de aclimatación también se observó diferencias estadísticas significativas entre las cruzas (P?0.05) debido a su condición genética

    Positive Influence Of A Dental Anaesthesia Simulation Model On The Perception Of Learning By Mexican Dental Students

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    Introduction: This study evaluated the influence of 3-repetition training with a dental anesthesia simulation model (DASM) on the perception of learning by dental students. Materials and methods: Dental students who had never used a dental anesthesia technique were randomly divided into 2 groups that were taught the anterior superior alveolar nerve infiltrative anesthesia technique. Group 1 (G1, N=10) followed a 3-stage learning method: 1st) theoretical lecture, 2nd) clinical demonstration, and 3rd) DASM training, including 3 repetitions of the anesthesia technique. Group 2 (G2, N=10) followed only the 1st and 2nd stages. The students in both groups then performed the anesthesia technique. The perception of the students was evaluated by 4 learning concepts. Each was evaluated with a 5-point Likert Scale questionnaire. The average score of each item of the questionnaire for G1 was compared with that of G2. Statistically significant differences were identified with the Mann-Whitney test. The average working time of each group was timed and compared by Student’s t-test to identify possible statistically significant differences. Results: Students in G1 showed higher average scores of perception in controlling the handling of the dental syringe and confidence in performing the injection (p\u3c0.05), and showed an average working time shorter than that of the students in G2 (p\u3c0.05). Conclusion: The DASM positively influenced the perception learning of the dental students; it increased their confidence and syringe handling ability, as well as skills to perform the injection of anesthesia more quickly

    Antioxidant activity of pineal methoxyindoles on hepatocyte plasmatic membrane

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    Antioxidant effect of several pineal derived molecules has been well documented. Here, the protective effects of 5-methoxytryptophol (5-MTOH) and 5-methoxyindol-3-acetic acid (5-MIAA) on hepatic cell membrane lipid peroxidation and cell membrane rigidity induced by FeCl3 plus ascorbic acid have been systemically investigated. The membrane fluidity was evaluated by fluorescence spectroscopy, malondialdehyde (MDA) and 4-hydroxyalkenals (4-HDA) concentrations and carbonyl groups of protein were measured as the parameters of lipid and protein damage, respectively. Results showed that oxidative stress increased membrane rigidity, MDA and 4-HDA concentra-tions as well as carbonyl content in a concentration-dependent manner. 5-MTOH, but not 5-MIAA, significantly attenuated these oxidative indecies. In absence of oxidative stress, none of these methoxyindoleamines modified the content of MDA, 4-HDA or carbonyl-ation. However 5-MIAA at its highest concentration slightly modified membrane fluidity. The results suggest that structural modification of C3 in the methoxyindoleamine, that is, the carboxyl group replaced by hydroxyl group in this site could improve the ability of 5-methoxyindoleamine derivatives to preserve membrane fluidity of cells which are under oxidative stress

    Selective enzyme-mediated extraction of capsaicinoids and carotenoids from chili guajillo puya (Capsicum annuum L.) using ethanol as solvent

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    The selective extraction of capsaicinoids and carotenoids from chili guajillo “puya” flour was studied. When ethanol was used as solvent, 80% of capsaicinoids and 73% of carotenoids were extracted, representing an interesting alternative for the substitution of hexane in industrial processes. Additionally, when the flour was pretreated with enzymes that break the cell wall and then dried, extraction in ethanol increased to 11 and 7% for carotenoid and capsaicinoid, respectively. A selective two-stage extraction process after the treatment with enzymes is proposed. The first step uses 30% (v/v) ethanol and releases up to 60% of the initial capsaicinoids, and the second extraction step with industrial ethanol permits the recovery of 83% of carotenoids present in the flour

    Ultrasound Application to Improve Meat Quality

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    High-intensity ultrasound offers an alternative to traditional methods of food preservation and is regarded as a green, versatile, popular, and promising emerging technology. Ultrasound generates acoustic cavitation in a liquid medium, developing physical forces that are considered the main mechanism responsible for the observed changes in exposed materials. In meat, ultrasound has been successfully used to improve processes such as mass transfer and marination, tenderization of meat ,and inactivation of microorganisms. It is also an alternative to traditional meat aging methods for improving the quality properties of meat. Moreover, the combination of ultrasonic energy with a sanitizing agent can improve the effect of microbial reduction in foods. This review describes recent potential applications of ultrasound in meat systems, as well as physical and chemical effects of ultrasound treatments on the conservation and modification of processed meat foods

    Positive influence of a dental anaesthesia simulation model on the perception of learning by Mexican dental students

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    Introduction: This study evaluated the influence of three-repetition training with a dental anaesthesia simulation model (DASM) on the perception of learning by dental students. Materials and methods: Dental students who had never used a dental anaesthesia technique were randomly divided into two groups that were taught the anterior superior alveolar nerve infiltrative anaesthesia technique. Group 1 (G1; N = 10) followed a three-stage learning method: (i) theoretical lecture, (ii) clinical demonstration and (iii) DASM training, including three repetitions of the anaesthesia technique. Group 2 (G2; N = 10) followed only the 1st and 2nd stages. The students in both groups then performed the anaesthesia technique. The perception of the students was evaluated by four learning concepts. Each was evaluated with a 5-point Likert scale questionnaire. The average score of each item of the questionnaire for G1 was compared with that of G2. Statistically significant differences were identified with the Mann–Whitney test. The average working time of each group was timed and compared by Student's t-test to identify possible statistically significant differences. Results: Students in G1 showed higher average scores of perception in controlling the handling of the dental syringe and confidence in performing the injection (P < 0.05) and showed an average working time shorter than that of the students in G2 (P < 0.05). Conclusion: The DASM positively influenced the perception learning of the dental students; it increased their confidence and syringe handling ability, as well as skills to perform the injection of anaesthesia more quickly

    An educational environment based on digital image processing to support the learning process of biomaterials degradation in stem cells

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    [Abstract] The Poly(DL-lactide-co-glycolide) copolymers (PDLGA) have designed and performed as biomaterials, taking into account their biodegradability and biocompatibility properties. These materials have a wide range of application in medicine such as orthopedic implants, general surgical implants (suture materials), osteosynthesis, bone cement, among many others. For these reasons, in this paper, we present an intelligent educational environment that can be used for both, researchers and students interested in the analysis of the biomaterial behavior under certain conditions. Our platform includes a Learning Objects (LOs) for MOODLE, and in the same way, implements several digital image processing techniques as well as a decision support module based on a random forest algorithm and statistical modeling. With the aim of determining the real feasibility of this proposal, we have presented the system to 34 Ecuadorian engineering students. After testing the platform, the students answered a survey aimed at determining their perception of the system. The results provide several guidelines to continue with the developing of the platform

    Refractory hyperactive bladder treated with sacral neuromodulator: case report and literature review

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    The overactive bladder syndrome is a chronic medical condition that affects the quality of life of patients whether men or women, has a prevalence of 16.5%, however, it is known to increase with age, affecting up to 25% of women older than 65 years and up to 80% in the elderly. More than 90% of cases have no apparent cause.  The OAB (Overactive Bladder) It is a condition with characteristic symptoms of urinary urgency, usually accompanied by frequency and nocturia, with or without urge incontinence, in the absence of urinary tract infection or other obvious pathology. The different therapeutic steps are not always sufficient to restore the quality of life

    Raman-Mössbauer-XRD studies of selected samples from “Los Azulejos” outcrop: A possible analogue for assessing the alteration processes on Mars

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    The outcrop of “Los Azulejos” is visible at the interior of the Cañadas Caldera in Tenerife Island (Spain). It exhibits a great variety of alteration processes that could be considered as terrestrial analogue for several geological processes on Mars. This outcrop is particularly interesting due to the content of clays, zeolite, iron oxides, and sulfates corresponding to a hydrothermal alteration catalogued as “Azulejos” type alteration. A detailed analysis by portable and laboratory Raman systems as well as other different techniques such as X ray diffraction (XRD) and Mössbauer spectroscopy has been carried out (using twin-instruments from Martian lander missions: Mössbauer spectrometer MIMOS-II from the NASA-MER mission of 2001 and the XRD diffractometer from the NASA-MSL Curiosity mission of 2012). The mineral identification presents the following mineral species: magnetite, goethite, hematite, anatase, rutile, quartz, gregoryite, sulphate (thenardite and hexahydrite), diopside, feldspar, analcime, kaolinite and muscovite. Moreover, the in-situ Raman and Micro-Raman measurements have been performed in order to compare the capabilities of the portable system specially focused for the next ESA Exo-Mars mission. The mineral detection confirms the sub-aerial alteration on the surface and the hydrothermal processes by the volcanic fluid circulations in the fresh part. Therefore, the secondary more abundant mineralization acts as the color agent of the rocks. Thus, the zeolite-illite group is the responsible for the bluish coloration, as well as the feldspars and carbonates for the whitish and the iron oxide for the redish parts. The XRD system was capable to detect a minor proportion of pyroxene, which is not visible by Raman and Mössbauer spectroscopy due to the “Azulejos” alteration of the parent material on the outcrop. On the other hand, Mössbauer spectroscopy was capable of detecting different types of iron-oxides (Fe3+/2+-oxide phases). These analyses emphasize the strength of the different techniques and the working synergy of the three different techniques together for planetary space missions.The work was supported by the MICINN with the Project AYA-2008-04529.Peer reviewe
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