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La guayaba (Psidium guajava) se puede caracterizar por su diversidad genética y sus cualidades morfológicas, fisicoquímicas y biológicas, las cuales dependen de factores exógenos como: cultivo agronómico, época de cosecha y madurez. Caracterizada por su contenido de carbohidratos (13.2%), grasas (0.53%), proteínas (0.88%) y gran contenido de humedad (84.9%). Es importante caracterizar la guayaba ‘media china’ cultivada en el municipio de Juárez, Michoacán, con el objetivo de mejorar características morfológicas, fisicoquímicas, biológicas, nutritivas y variables estadísticas en control de calidad para correlacionarlas a la posibilidad de industrializarla y comercio internacional. Para tal fin, se utilizó la metodología sistémica de los ‘diagramas de bloques de confiabilidad’ que incluyó muestreo aleatorio de la guayaba para estudio, en el que se determina: peso, diámetros longitudinal, transversal, pulpa, espesor y pH. Se obtuvieron; media aritmética, varianza y desviación estándar, variables para graficar y comparar con normas establecidas para comercio nacional e internacional. Como resultado se encontró que, la guayaba procedente del municipio de Juárez, Michoacán, presentó los mejores resultados en su caracterización. La guayaba cultivada en la huerta del municipio de Calvillo en el estado de Aguascalientes presentó resultados menores, se observó que fue superada la calidad por la fruta de Juárez Michoacán. Las características en tamaño, apariencia visual, contenido de semilla del fruto, observadas en las muestras compiten con las de las variedades comerciales. El análisis de esta investigación infiere las siguientes conclusiones: el sistema productivo del cultivo en el estado de Michoacán y Aguascalientes, están en condiciones de ofertar guayaba de buena calidad para su comercialización nacional e internacional, debido a las buenas prácticas agrícolas aplicadas y su registro al Servicio Nacional de Sanidad Inocuidad y Calidad Agroalimentaria de la Dirección General de Sanidad Vegetal de la Secretaría de Agricultura y Desarrollo Rural.

Phenolic compounds of breads added with turmeric at different concentrations (A: 0, B: 1.25, C: 2.5, D: 5 and E:10%) and radiated by UV-C (I. 0, II. 15, III. 30 and IV. 60 s), have been evaluated by HPLC (High-performance liquid chromatography). It is shown that: (i) UV-C radiation modifies the content of phenolic compounds as a function of the percentage of addition of turmeric and the exposure time. There were significant differences (ρ ≤ 0.05) in the concentration of phenolic acids of the turmeric bread (TB): 0 s (sinapic, chlorogenic, protocatechuic), 15 s (chlorogenic, ferulic, protocatechuic, p-hydroxybenzoic, gallic), 30 s (chlorogenic and gallic) and 60 s (chlorogenic). (ii) In TB without radiation appeared, the sinapic, beta resorcylic, syringic and ferulic acids. In the radiation of bread at 15 s, the phenolic acids chlorogenic, ferulic, protocatechuic, p-hydroxybenzoic, gallic, had the highest concentration in the breads added with turmeric at 10% (0.02 μg mL−1), 10% (0.38 μg mL−1), 1.25, 2.5, 5% (0.39 μg mL−1), 10% (1.06 μg mL −1) and 0% (1.10 μg mL−1). (iii) There was a degradation of phenolic acids due to UV-C radiation at 30 and 60 s. At 15 s radiation, sinapic, beta resorcylic, syringic and ferulic acids were not detected in turmeric breads from breads added with turmeric at (1.25, 1.25, 0 and 0%). In radiation at 60 s, beta resorcylic, syringic and ferulic acids were not detected in any bread added with turmeric. In addition, measurements of proximate chemistry, color, sensory analysis, and number of fungal colonies were performed. It is important to mention that the sanitary quality is improved by both UV-C radiation and turmeric. However, the highest results in sanitary quality improvement were due to turmeric.

Due to the confinement at home that is lived in various countries by the pandemic of the new coronavirus COVID-19 in Wuhan, China and its spread worldwide. Changes have been brought about in the daily life of the population, for example the way of carrying out academic and professional work. Work hours increased and with it the use of various visual devices to carry out activities. Therefore, the objective of this research was to evaluate the state of visual health and ergonomics by the population during the health contingency. An evaluation instrument generated in the "Microsoft Forms" software was applied to evaluate ergophthalmology and visual health. An absolute positive correlation was found in the symptoms of blurred vision and muscle pain in the male gender, while for the female gender an absolute correlation was reported in the glare symptom and a positive correlation in dry eye, red eye, burning, tearing and muscle pain. Therefore, it is of utmost importance to disseminate ergophthalmic measures to reduce the visual symptoms of the population.

Magnetite (Fe3O4) nanoparticles (MNPs) below 30 nm are considered addressable magnetic cores which can be stimulated by an external AC magnetic field. In this study, MNPs were covered directly with Curcuma longa extract from a modified coprecipitation route as an organic base. The particle size distribution ranging from 9 to 18 nm according to transmission electron microscopy (TEM) and dynamic light scattering (DLS). Two main particle size populations were found associated with particle aggregation in the samples. In addition, their thermal features were determined using photothermal techniques to obtain their thermal diffusivity, effusivity, conductivity, and heat capacity per unit volume. The thermal diffusivity and effusivity values of the MNPs were obtained using a thermal wave resonator cavity (TWRC) and inverse photopyroelectric (IPPE) photothermal techniques, respectively. The obtained thermal parameters were similar to the water thermal values because the MNPs were measured in aqueous solutions. The main goal of this study was to define the thermal response, by obtaining the thermal characterization, of MNPs in suspensions related to superparamagnetic cores and Curcuma longa coatings.

The present project was aimed toward obtaining a model of sustainable gardening practices for a horticultural intervention (HI) in Ahuazotepec, Mexico. Different mulching materials (sand, compost, ...

International audience; The pro-health action of germinated lentils could be useful to be added with wheat flour in the production of box bread. In this work, we spectroscopically evaluate the germinated and non-germinated lentils, and use them at the concentrations of 5 and 10% for the production of box bread. The chemical and physical tests of the bread and its determination of phenolic acids and flavonoids (by HPLC) were also performed. As well as the evaluation of the quality of flour and dough used to produce the bread and the acceptance of the germinated lentil bread with a population of 20 people with diabetes or with diabetic relatives It is shown that: (1) The amplitude of photoacoustic signal obtained by photoacoustic spectroscopy is modified as a function of the percentage of germinated lentil (GL) flour (0, 5 or 10%) add to the bread; being higher the photoacoustic amplitude to higher concentration of GL in the absorption band of 300–425 nm, which is related to higher content of phenols and flavonoids. (2) The contents of phenolic acids (Sinapinic, β- resorcylic, Chlorogenic and Ferulic) and flavonoids (Quercetin and Isorhamnetin) tended to increase in the germinated lentil bread with 10% concentration of germinated lentil flour with respect to the control bread (0% GL). (3) The addition of germinated lentils flour to 5 and 10% into wheat flour to produce bread with higher hardness and less cohesiveness than bread based on wheat flour only. The Falling number indicate that there is no significant difference between the control sample and the 5% GL flour, while in the 10% GL flour there was a reduction of 21 s, with respect to the control. The effect of the germinated lentil flour percentage on the pasting properties of the flours was significant between the control and 10% GL flour. In general, the quality of the dough and flour are modified due to the addition of germinates lentils, and this affectation increases with the increase in the concentration of GL. (4) The bread added with germinated lentil has sensory acceptance with a group of people with diabetes and/or diabetic relatives in their attributes in general. The obtained results thus support the production of wheat bread with mixed germinated lentils flour, as a nutraceutical option for human consumption.

We report on characterization of bio-additive from Jatropha curcas L. oil (JBA) in mineral-based oil (MBO) at different viscosities with 10 % and 20 % ratios blends of JBA. Measurements of kinematic viscosity and mass density were carried out to know the physical changes of MBOs when JBA is added. Also, a thermal characterization of the samples was performed. The thermal conductivity, k, and specific heat, c, were obtained using their relationship with thermal effusivity, e, and thermal diffusivity, α, which were determined by the front and back photopyroelectric techniques, respectively. We show that a correlation between kinematic viscosity and thermal conductivity exists with the percentage of JBA in the blend. The obtained thermal conductivities values were compared with those retrieved using the hot-wire technique showing a good agreement. JBA demonstrated special features to improve the thermal properties and to be able to be used as a viscosity modifier of the MBOs, which could be reflected in a better performance in machinery that uses engine oil.

International audience; Photoacoustic spectroscopy is applied to evaluate the impact of Moringa at different concentrations (0, 1.25, 2.5, 5 and 10%) on the elaboration, sanity, texture, and color of wheat bread. It was found that: i) Photoacoustic signal amplitude values of bread significantly increase from 37 to 90% when moringa powder concentration raises from 1.25% to 10%, at 300 nm wavelength. ii) Comparing the photoacoustic signal values at 300, 330, and 370 nm wavelengths, produced by the different bread types, there were statistically significant differences. iii) The sanitary quality of bread mixed with a 2.5% of moringa is relatively higher than the ones obtained for other concentrations, such that the number of fungal colonies were reduced by 99% in comparison with the control bread without moringa, after six days of storage. Moringa at 2.5% of concentration could thus improve the sanitary quality of wheat bread. iv) The addition of moringa for making bread slows down its textural changes (hardness, elasticity, cohesiveness, resilience, and chewiness) during storage. v) Finally, the highest correlation between the photoacoustic amplitude and the moringa concentration occurs at the wavelengths of 300 and 330 nm, which could be related to significant changes in the content of flavonoids and phenolic acids.

International audience; We quantitatively evaluate the effects of UV-C radiation on bean seeds Oti (Phaseolus vulgaris), their germination and phenolic compounds of seedlings, by means of photoacoustic spectroscopy and scanning electron microscopy. It is shown that (i) The photoacoustic signal produced by the bean seeds exposed to UV-C radiation during 15 min, reduces from 0.24 to 0.10 mV for the wavelengths of 295 and 340 nm, as a result of their degradation. This significant reduction of 58.3% decreases, but keeps over 50% for other spectral UV wavelengths within the interval (270-400 nm). (ii) As the UV-C radiation time increases from 2 to 15 min, the morphological changes at the surface of the bean seeds exhibit micro-holes and detachment of the cotyledon sclereids. (iii) There are no significant statistical differences in the variables of germination, dry weight, and seedling length, for exposure times up to 15 min. (iv). The phenolic acids and flavonoids of the bean seedlings of seeds treated by UV-C for different exposure times (0, 2, 5, 10, and 15 min) display significant statistical differences (P ≤ 0.05) in both roots and foliage. For both the roots and foliage, the highest concentration of phenolic acids is observed at 10 and 15 min, while for root flavonoids, it appears at 5 and 15 min.

During the last decades, digital image processing algorithms have been developed to measure external characteristics of agricultural products due to the great potential that these methods offer. So, in this research, the thermal images obtained from a thermographic camera were analysed considering two genotypes of maize seeds: crystalline and floury in their natural state, previously irradiated with a laser light source of 650 nm for exposure times of 15 s and 35 s. The methods applied in the analysis were: a) histogram to obtain the distribution of gray levels of images, b) mean value that indicates the brightness of images, c) variance which means the contrast of images, d) entropy applying both Shannon and Tsallis definitions, which provide the average self-information of images, e) estimation of the probability density of temperature variations on seeds to quantitatively characterize them from thermal images. Higher mean and variance were obtained from crystalline seeds indicating higher brightness and contrast. Furthermore, thermal images of floury seeds had higher entropy of Shannon indicating that images had greater disorder with respect to images of crystalline seeds. In the case of the entropy of Tsallis, the entropic index q could be used for characterization of seeds. Thermal images obtained from seeds with a floury structure provided a higher redundancy value for a shorter exposure time to laser light. Thus, the viability of the statistical methods of digital image processing applied to thermal imaging for the characterization of seeds is shown.

Currently evaluation of agricultural product quality is of great importance, in order to guarantee a consumption free of contaminants. In different research areas several techniques are used to evaluate food attributes, related to its quality. Among the techniques used to characterize food stuffs, photothermal techniques have shown versatility to obtain different physical parameters of foods. In the present investigation, the temperature variation effects of different varieties of corn kernels, when excited by laser light during 60 s, were obtained from digital and thermal images, which were analyzed by using artificial vision for characteristic color patterns and geometric measurements to observe the thermal effects, respectively. From these images it was possible to observe variations in temperature, through differences in digital and thermal images of corn samples. Also photoacoustic (PA) spectra were obtained in a wavelength range from 300 to 750 nm, for each variety of corn kernels. Different behaviors of both, image analysis and the PA spectra, showing that one variety of corn kernels present a greater response in both techniques compared to the other varieties. The information obtained could be used in food production areas to identify, classify and determine attributes of grains and seeds of different types of crops.

In this documentary investigation, we review literature about the transdisciplinary perspective (TD) to generate knowledge, locating its origin, evolution and characteristic features. It is found that: i) This origin is located in France and the United States, although some characteristic features related to self-knowledge, participatory research and the unity of knowledge, were proposed before the creation of this TD term introduced in 1970. ii) The concept of transdisciplinarity has evolved over time involving a transition of vision towards the application of perspective to investigate. Switzerland was the first country to apply the transdisciplinarity in research in the 1990s. iii) The key world events that gave impetus to the transdisciplinarity are the world (1994) and Zurich (2000) congresses, as well as the special edition entitled “the foundation of Academy of Transdisciplinary Learning of Advanced Studies (ATLAS)” of the Journal "Futures" (2004) and the 10th anniversary edition of the Transdisciplinarity Journal of Engineering & Science (TJES) in 2010. iv) the main features of transdisciplinary research are: a) research for society and with society, i.e. participatory research, b) scientific research under systemic thinking, c) communication of results to the scientific community and disseminated to non-scientific population. v). The number of transdisciplinary research publications have increased over time, along with the quantity of authors per publication and citations thereof. Some contributions from the 90s were the most impactful due to the number of cites today. The transdisciplinary approach could be the best pathway to develop research in Latin American countries and the world, for solving the diverse problems of society.

The use of photothermal techniques has become of special importance due to their versatile application in the thermal characterization of materials. Therefore, the thermal lens technique in the mismatched dual-beam mode is an alternative, sensitive and non-evasive tool that was used in this research to determine the thermal diffusivity of Moringa oleifera. The dual arrangement of the thermal lens technique is based on the use of an Ar+Xe excitation laser (422 nm) and a He–Ne laser (632 nm) test laser. Moringa solutions were prepared by green synthesis with different concentrations ranging from 1.56 mg·mL−1, 3.12 mg·mL−1, 6.25 mg·mL−1 to 12.50 mg·mL−1. Different optical techniques (UV–vis, FTIR, XPS and EDS) were used to characterize the Moringa leaf powders. Results showed that the increase of thermal diffusivity could be related to the presence of functional groups and metallic elements in Moringa elemental composition. In this work, it was found that the thermal diffusivity of Moringa increases with increasing concentration. This study will be useful for application in heat transport and drug release.

High pollution rates in large cities have had a negative impact on human, animal and plant health. In the case of plants, several techniques have been used to analyze the physical and physiological parameters of their seedlings and seed germination process, under different environmental conditions. This study proposed the evaluation of seedlings from corn, lentils and bean seeds, exposed to polluting gases (CO, CO2) through a container system of a vehicle engine, during different times (0, 20, 40, 60 and 80 min). The seeds, after the exposition to the pollutant gases, were planted, and the optical absorption spectra of each seedling were obtained by photoacoustic spectroscopy. The absorption spectra were obtained in a wavelength range from 250 to 750 nm. The obtained spectra demonstrated significant statistical differences in the wavelength range from 290 to 300 nm (corresponding to optical absorption mainly by flavonoids) and also from 650 to 680 nm (corresponding to optical absorption of chlorophylls). In addition, changes in physiological parameters, during the seed germination process, were evaluated.

International audience; In this research, we to apply photoacoustic spectroscopy and evaluate bread added with turmeric (Curcuma longa Linnaeus) at different concentrations in relation to wheat flour weight (0, 1.25, 2.5, 5 and 10%). The amplitude of the photoacoustic signal was related to measures of antioxidant activity and evaluate the sanitary quality and also, the texture, color and sensory acceptability of the breads. It is shown that: i) The photoacoustic signal produced by bread significantly increases with the turmeric concentration, such that it raises more than 100% for a concentration of 10% at the wavelengths of 428 and 515nm. ii) The Bread antioxidant activity is directly proportional to the level of photoacoustic signal at 515 nm and its value increases from 73.21% to 91.73%, when the concentration increases from 0 to 10%. iii) The sanitary quality of bread added with 2.5 % of turmeric is relatively higher than the ones obtained for other lower concentrations. No fungal colonies were observed in bread mixed with 2.5%, 5% and 10%, after six days of storage. iv) The addition of turmeric powder for bread making can slow down their textural changes (hardness, elasticity, cohesiveness, resilience and chewiness) during storage. v) Bread at 2.5 and 5% of turmeric concentration showed the yellowest color, while the one with a 10% concentration exhibited the most reddish color. Finally, through Principal component analysis it was possible to demonstrate that a concentration of either 5 or 10% of turmeric added to wheat flour could be used to improve its sanitary quality and antioxidant activity.

Scientific reports around the world indicate that solar radiation has increased its intensity and consequently its UV radiation, making it necessary to improve protective materials against this radiation. Textiles can be used as a protective material against the UV radiation, and one way to increase their UV protection capacity could be by adding biomaterials with optical absorption in the UV region. In the present study, flavonoids, natural pigments absorbing UV radiation, were extracted from corn seeds by using two methods (maceration and microwave oven assisted). The extracted flavonoids as well as a commercial protector of UV-B radiation were added to a cotton textile and then exposed to different UV-B radiation times (0 min, 30 min and 60 min). The optical absorption spectra of flavonoids and textile materials were obtained by photoacoustic spectroscopy. These spectra showed differences, observing that the textile added with commercial protector was degraded with the exposition of UV radiation; meanwhile in the case of the textile added with flavonoids increased its UV protection.

Maize grains were treated with electromagnetic fields and nixtamalized with nejayote, in order to analyze the effect of such treatments on the microbiological and viscoelastic properties of masa, and on sensory tests of tortilla. A sample of maize grains was irradiated by electromagnetic fields for 7 and 12 min.Then, following the nixtamalization with nejayote, masa and tortillas were obtained. The application of electromagnetic fields did not decrease the growth of moulds in maize grains. However, a synergistic effect of irradiation (12 min) and nixtamalization with diluted nejayote (50 water/50 whole nejayote) improved the sanitary quality of masa. Elastic and viscous moduli showed significant differences in all treatments. The masa from maize grains irradiated for 12 min showed the highest values of elastic and viscous moduli, while the masa from grains irradiated for 7 min and nixtamalized with diluted nejayote (70 water/30 whole nejayote) presented the lowest values. These results seem to indicate that the application of electromagnetic fields modifies the viscoelastic modulus of masa. Sensory tests showed that tortillas obtained from irradiated (12 min) maize grains, nixtamalized with nejayote (70 water/30 whole nejayote), had the highest score of all the attributes, i.e. texture, chewiness and taste.

La industria de la masa y la tortilla enfrenta algunas problemáticas, sobre todo, en el insumo maíz que ha tenido f luctuaciones constantes en su precio. Por ello, este trabajo tuvo como objetivo evaluar económicamente la industria de la masa y la tortilla de maíz en el Estado de México, con el fin de determinar su rentabilidad. El método de evaluación de proyectos de inversión se usó para obtener los indicadores financieros como el Valor Actual Neto (VAN), la Tasa Interna de Retorno (TIR) y la relación Beneficio Costo (B/C). La información se obtuvo durante 2015 mediante una encuesta aplicada a 367 molinos y tortillerías de la entidad. El análisis se dividió por tipo de establecimiento, materia prima principal utilizada en el proceso de producción y tamaño del establecimiento. De acuerdo con los resultados, las tortillerías más rentables son los establecimientos que usan maíz y harina nixtamalizada como materia prima. También se encontró que las empresas grandes y medianas son más rentables que las pequeñas. En conclusión, las tortillerías pequeñas son las más sensibles a las variaciones de los precios del maíz.

Over the last years extensively research has been carried out on full or partial substitution of supplies resources coming from renewable resources on traditionally non-renewable, in the case of the automobile sector there are progresses in bio-combustibles (biofuel) and synthetic oils coming from vegetable sources. There are strong efforts to find oil additives which can improve oils features in automobile industry, by adding vegetables oils to commercial lubricant oils, is expected to improve oil thermal stability. In the present research, different ratios of castor oil (ricinus comunis)-motor oil blends were obtained and their thermal properties were characterized by using the so-called Back and Front Photopyroelectric (BPPE/FPPE) techniques. Several oil-additives concentrations were measured and thermal diffusivities and effusivities as well as densities are reported, getting full thermal characterization for every concentration.

The sustainability of the traditional maize agroecosystem in Ahuazotepec, Mexico, was evaluated using a cluster analysis for the typification of the producers and the Framework for Assessin...

In maize plant breeding aimed at producing a hybrid, it is necessary to characterize the parents and hybrids by their agronomic aspects and grain quality so that the processing industry may offer consumers a quality product and also improve its efficiency. This study evaluated the viscoelastic parameters of masa and the chemical and texture properties of tortillas obtained from parent lines (M-54, M55, and CML-242), two single crosses (M54xM55 and M55xM54), and one hybrid (H-70). The morphology of the maize grains and tortillas was analyzed using scanning electron microscopy. The firmness of masa obtained from CML-242 and H-70 maize was higher than that from the other maize genotypes. M-54 tortillas showed the lowest crude fiber content. Otherwise, tortillas obtained from the M55xM54 hard grain had the lowest fat content and extensibility, while H-70 tortillas showed an intermediate breaking point and extensibility. M-54 and M54xM55 tortillas were softer due to their more swollen starch granules. In contrast, rigid tortillas were obtained from CML-242 and H-70. Grain hardness causes different morphology in starch and tortilla of maize genotypes. However, grain hardness did not influence the characteristics of texture in tortillas.

In the present study, the thermal effusivities of human fluids, such as human blood serum, urine, saliva and tears, were obtained by the photopyroelectric (PPE) technique in inverse configuration (IPPE). Human blood serum and urine were obtained from studies carried out in a government hospital for public servants in Mexico City, whereas saliva and tears were artificial. Making use of both, the amplitude and phase of the PPE signal, the thermal effusivities of each one of the mentioned human fluids were obtained. In order to obtain them, the experimental PPE data were normalized to the PPE signal with air as sample and the theoretical PPE equation was fitted to the normalized experimental data.

The study of structures in different materials is increasingly important. In many cases, these materials have different layers that compose them, and it is not easy to observe or detect some internal structures or damages without destroying the samples. Photothermal (PT) techniques, such as photoacoustic spectroscopy, photoacoustic (PAM) and photopyroelectric microscopies, are valuable nondestructive techniques. PT microscopies allow to make scans of samples in order to obtain their thermal images. In this study, thermal images of two different samples were obtained, by using PAM at different excitation wavelengths.

Photothermal techniques are useful experimental methodologies for characterization of the optical and thermal parameters of different materials like maize seeds due to its advantages such as non-invasive and non-destructive nature. Among these techniques, the photopyroelectric microscopy was applied in the present research to obtain thermal images where each of their coordinates represents amplitude values of the photopyroelectric signal, indicating differences in the structural components of both genotypes of maize seeds. The random variations of the amplitude of the photopyroelectric signal caused by the heterogeneous nature of the thermal properties of the samples, were represented by histograms to identify the probability density function underlying the data sample, observing that in the case of the maize seed with floury structure, the amplitude variations could be described statistically by the transformed Moyal distribution when a linear transformation with censored data was applied to the data set obtained from the thermal image with a significance level of 0.001, according to the Kolmogorov–Smirnov statistical test for goodness-of-fit. In the case of the photopyroelectric signal obtained from a maize seed with crystalline structure, it was not possible to describe statistically the amplitude variations of the signal by means of the transformed Moyal distribution because it did not pass the Kolmogorov–Smirnov test, so the same statistical test for goodness of fit was applied to both genotypes of maize seeds for analyzing the populations of the data sample, in order to find the distributions that best fit each population with a significance level of at least 0.05 increasing in this way the power of the test. The distributions with the best fit were logistic, log-logistic, uniform, least extreme value and normal.

Vegetable oils can undergo changes in their physical and chemical properties when they are subjected to processes such as extraction, purification, cooking, frying, or chemical modifications that are required depending on their application in the food industry. In the present research, different methods were used to determine physical, chemical, and thermal properties of avocado, sesame, extra virgin flaxseed, extra virgin olive, and grape seed oils, in order to evaluate and compare the compositional effects of each vegetable oil. By using an adiabatic scanning calorimeter, an alternative calorimetric method, the specific heat of five vegetable oils was obtained as a function of the temperature, in the range of 25–90 °C. The fatty acid profile was determined via gas chromatography. Monounsaturated acids present in avocado and extra virgin olive oil cause higher specific heat values in these oils, and the presence of polyunsaturated acids, contained mainly in extra virgin flaxseed oil, reduces the specific heat values. We found an almost linear behavior of vegetable oil specific heats, as a function of the temperature, and the slopes of these linear fits depend on the contained percentage of polyunsaturated fatty acids in the vegetable oil. The unsaturated acids are an important factor to analyze the behavior of specific heat of vegetable oils. The obtained specific heat values were compared with the estimation from the Rowlinson–Bondi equation, for specific heat of vegetable oils, giving a very good adjustment, mainly in a temperature range near to the room temperature.

Diversos laseres han demostrado ser potencialmente utiles a determinados parametros de irradiacion y podrian beneficiar el establecimiento de siembra en condiciones adversas por radiacion UV-B, sequia, frio, salinidad, contaminacion por cadmio, etc. Esta revision de literatura cientifica exhibe las aplicaciones posibles de los laseres en los ultimos anos, como tratamiento de semillas y plantas, destacando el uso de los laseres de He-Ne, Ar, Neodimio-YAG, CO y los diodos laser. Es evidente que las aplicaciones de laseres a parametros de irradiacion especificos en semillas y plantas han adquirido cada vez mayor importancia debido a la necesidad de incrementar la produccion de alimentos a nivel global mediante metodos que protejan el medio ambiente y contribuyan a combatir los efectos del cambio climatico y a la conservacion de la biodiversidad, mejorando la calidad de vida humana y animal. De esta manera, en este Ano Internacional de "la Luz y las tecnologias basadas en la luz", fue importante tomar conciencia del posible uso potencial de la luz laser en la agricultura, ya que podria coadyuvar a un desarrollo sostenible y ofrecer soluciones a problematicas diversas. Los avances encontrados por diversos cientificos lo evidencian y en los proximos anos podria tener un auge en su aplicacion en la agricultura como un elemento "bioestimulador" de semillas, plantulas y plantas.

Photoacoustic spectroscopy (PAS) has been widely used to analyze biological samples. For example, PAS has been applied to the study of blood which could be related to some diseases. In the present research, the optical absorption spectra of Fisher rat blood, with hepatic damage, were obtained by PAS. Also, the daily intake of turmeric (Curcuma longa), as a protection of liver damage, was evaluated through the characteristic optical absorption peaks of blood, α(585 nm), β(550 nm), and γ(420 nm), where it is possible to associate them with differences in hemoglobin concentrations of the studied samples, by means of the peak ratios γ/β and γ/α, for each analyzed group.

In this work we present an interactive system capable of producing realistic artworks with acrylic paint based on a cartesian robot. This system focuses on painting artworks by regions, and can be applied for example in the painting of objects such as fruits, flowers, leaves and other individual objects. We have divided the development of the proposed system in three interactive stages: (1) interactive segmentation of work regions, (2) interactive designing of the field for orienting the brush strokes by tracing curves manually in each region and interpolating the curves to generate the vector field, and (3) painting by regions with the field. With our system it is possible to reproduce interactively an image producing pleasant results. The experimental results are presented by painting an apple with three main regions, for this we have utilized a realistic pictorial style and a monochromatic palette of 5 colors.

In recent years, has been reported an increasing interest to study vegetables and fruits in order to know their benefits to prevent different types of health problems. Curcuma longa has a great potential to prevent diseases as different types of cancer. In the present study, C. longa samples, of different trademarks, were optically and thermally characterized by using photoacoustic spectroscopy and photopyroelectric techniques, obtaining their optical absorption spectra, optical absorption length spectra, the thermal diffusivity, effusivity, conductivity and heat capacity per unit volume, observing optical absorptions corresponding to antioxidant elements, reported such as beneficial for health. These properties also could be important in the food industry for the commercialization of functional foods.

One of the most challenging problems of electrochemical therapy is the design and selection of suitable electrode array for cancer. The aim is to determine how two-dimensional spatial patterns of tissue damage, temperature, and pH induced in pieces of potato (Solanum tuberosum L., var. Mondial) depend on electrode array with circular, elliptical, parabolic, and hyperbolic shape. The results show the similarity between the shapes of spatial patterns of tissue damage and electric field intensity, which, like temperature and pH take the same shape of electrode array. The adequate selection of suitable electrodes array requires an integrated analysis that involves, in a unified way, relevant information about the electrochemical process, which is essential to perform more efficiently way the therapeutic planning and the personalized therapy for patients with a cancerous tumor.

Laser light as a biostimulator has been applied in agriculture, and some scientific reports evidence its usefulness. A knowledge about seed optical parameters is of great relevance in the biostimulation process, because information can be provided about the light absorption of seeds. Thus, the objective of the present study was to determine the optical absorption coefficient ( $$\beta $$ ) of barley (Hordeum vulgare L.) seeds by means of photoacoustic spectroscopy; these seeds were studied in two conditions: seeds in their natural color and seeds dyed with methylene blue. The seeds were biostimulated by a laser beam (650 nm wavelength) to evaluate the effects of pre-sowing biostimulation in natural mycobiota associated with different laser irradiation times (0 s, 60 s, 120 s, 240 s, and 480 s). The results of this research demonstrated changes in the optical parameters (absorption and penetration) that occur in the seeds by changing the natural condition to a dyed condition. The dyed seeds, by the methylene blue photosensitizer, become optically opaque, producing greater optical absorption at 650 nm which causes an increase in the effect of laser stimulation. The experimental results showed that the biggest mycobiota reduction (52 %) corresponded to dyed seeds irradiated with a laser for 120 s.

In this research, the thermal evolution in maize seeds (Zea mays L.) was studied when low-intensity laser irradiation was applied during 60 s. The seeds were irradiated in three different conditions: suspended in air, placed on an aluminum surface, and finally placed on a cardboard; the evolution of the seed temperature was measured by an infrared camera. Photoacoustic spectroscopy and the Rosencwaig and Gersho model were used to determine the optical absorption coefficient ( $$\beta $$ ) of the seeds. The results indicate that using 650 nm laser light and 27.4 mW, it is possible to produce temperature changes (up to $$9.06~^{\circ }\hbox {C}$$ after 1 min) on the seeds. Comparing the mean temperature of the seeds, during and after the incidence of light from a laser, it was found that there were statistically significant differences ( $$P\le 0.05$$ ) from time $$t_{1}$$ to time $$t_{16}$$ ( $$t_{1}$$ to $$t_{16}$$ ) and $$t_{3}$$ to $$t_{16}$$ , for the laser turned on and off, respectively. The seed condition that had the highest temperature variation, relative to the initial temperature (during the irradiation laser exposure), involved the seeds suspended in air. With regard to the stage of decay of the temperature, it was found that the seed condition that decays more slowly was the seed placed on the cardboard. It was also found that black-dyed maize seeds are optically opaque in the 300 nm to 700 nm range Also, the thermal diffusion length is smaller than the optical penetration length. In the present investigation, it was shown that there is a thermal component associated with the mechanisms of laser biostimulation, which is also a function of the container materials of the seed. In this way, the effects of laser treatment on maize seeds involve at least a temperature effect. It is important to know the temperature changes in the seeds that have been irradiated with a laser beam since they could have substantial practical and theoretical importance.

Nixtamalization is an important process because it results in an increased calcium intake in consumers eating products that have been thus prepared. Nixtamalization generates a high amount of organic waste called nejayote. The objective of this research was to evaluate the chemical, textural, and viscoelastic properties of nixtamalized dough with the addition of nejayote and nejayote solids. A 4 × 4 two-factor (percentage of nejayote solids and nejayote concentration) factorial design was applied. Results demonstrated that ashes and CaCO3 increase significantly in nixtamalized dough with nejayote. Textural parameters, hardness, and cohesiveness of dough with nejayote solids added did not show significant differences. Nixtamalized dough with whole nejayote appears to increase hardness and decrease cohesiveness. Control dough and nixtamalized dough with diluted nejayote 1:1 (100 g nejayote:100 g water) and 30 g/100 g of nejayote solids added did not show significant differences in cohesiveness, resilience, total elasticity, storage modulus (G′), loss modulus (G″), and loss tangent (tan δ). Total elasticity of nixtamalized dough with diluted nejayote is higher than that of the control dough. Consequently, using diluted nejayote and adding nejayote solids during the nixtamalization process may be an appropriate method by which to reduce organic waste.

A b s t r a c t. It is important to know the temperature changes in seeds that have been irradiated with laser light because this could have substantial practical and theoretical importance. Thus, the thermal effects of low intensity laser irradiation on seeds was studied, showing variation of temperature produced by laser light applied during 60 s on two maize seed genotypes, ‘Toluqueno’ and ‘Cacahuazintle’: crystalline and floury, respectively, under two different conditions: natural colour and dyed black, evaluating the temperature changes by a thermal camera. The optical absorption spectra and the non-radiative relaxation time of the seeds were obtained using photoacoustic spectroscopy. The results indicate that it is possible to produce temperature changes, detected by an infrared camera, in crystalline and floury seeds when they are irradiated with a laser beam at a 650 nm wavelength and 27.4 mW power. The highest variation of temperature in the seeds was obtained for the black-dyed condition, these variations being 5.56 and 9.28°C for crystalline and floury seeds, respec tively. Among the seeds, in the dyed condition, the floury seed had the lower non-radiative relaxation time, the higher optical absorption coefficient and a lower optical penetration length at the laser wavelength (650 nm). K e y w o r d s: maize, temperature, thermal camera, laser

Photoacoustic spectroscopy (PAS) has been used to analyze agricultural seeds and can be applied to the study of seed depth profiles of these complex samples composed of different structures. The sample depth profile can be obtained through the photoacoustic (PA) signal, amplitude, and phase at different light modulation frequencies. The PA signal phase is more sensitive to changes of thermal properties in layered samples than the PA signal amplitude. Hence, the PA signal phase can also be used to characterize layers at different depths. Thus, the objective of the present study was to obtain the optical absorption spectra of maize seeds (Zea mays L.) by means of PAS at different light modulation frequencies (17 Hz, 30 Hz, and 50 Hz) and comparing these spectra with the ones obtained from the phase-resolved method in order to separate the optical absorption spectra of seed pericarp and endosperm. The results suggest the possibility of using the phase-resolved method to obtain optical absorption spectra of different seed structures, at different depths, without damaging the seed. Thus, PAS could be a nondestructive method for characterization of agricultural seeds and thus improve quality control in the food industry.

The objective of the present study was to obtain thermal images of a broccoli seed (Brassica oleracea) by photoacoustic microscopy, at different modulation frequencies of the incident light beam ((0.5, 1, 5, and 20) Hz). The thermal images obtained in the amplitude of the photoacoustic signal vary with each applied frequency. In the lowest light frequency modulation, there is greater thermal wave penetration in the sample. Likewise, the photoacoustic signal is modified according to the structural characteristics of the sample and the modulation frequency of the incident light. Different structural components could be seen by photothermal techniques, as shown in the present study.

"Se realizó una investigación en la Escuela Superior de Ingeniería Mecánica y Eléctrica del Instituto Politécnico Nacional de Ciudad de México, desde mayo hasta junio de 2016 , con el objetivo de determinar cómo cambia el patrón espacial del daño tisular con la forma del arreglo de electrodos en piezas tridimensionales de papa ( Solanum tuberosum L) bajo la acción de 10 mA durante 30 min para los arreglos de electrodos con formas colineal, circular, elíptic a, parabólic a e hiperból ica). Los resultados mostraron la estrecha relación entre el daño tisular y la forma del arreglo de electrodos, así como algunos hallazgos que se observa n también en tumores, tales como : necrosis circular alrededor de todos los electrodos, daño tisular ex tensivo en espacio y en tiempo, burbujeo alrededor del cátodo, zona blanca alrededor del ánodo ; igualmente, se observó que las regiones alejadas de los electrodos no se afectaron."

Vegetable oils have been widely studied as biofuel candidates. Among these oils, jojoba (Simmondsia chinensis) oil has attracted interest because it is composed almost entirely of wax esters that are liquid at room temperature. Consequently, it is widely used in the cosmetic and pharmaceutical industries. To date, research on S. chinensis oil has focused on to its use as a fuel and its thermal stability, and information about its thermal properties is scarce. In the present study, the thermal effusivity and conductivity of jojoba oil between $$20\,{^{\circ }}\hbox {C}$$ and $$45\,{^{\circ }}\hbox {C}$$ were obtained using the inverse photopyroelectric and hot-ball techniques. The feasibility of an inverse photopyroelectric method and a hot-ball technique to monitor the thermal conductivity, and the thermal effusivity of the S. chinensis is demonstrated. The thermal effusivity decreased from 538 $$\hbox {W}\cdot \,\hbox {s}^{1/2}\cdot \,\hbox {m}^{-2}\cdot \,\hbox {K}^{-1}$$ to 378 $$\hbox {W}\cdot \,\hbox {s}^{1/2}\cdot \,\hbox {m}^{-2}\cdot \,\hbox {K}^{-1}$$ as the temperature increased, whereas the thermal conductivity remained the same over the temperature range investigated in this study. The obtained results provide insight into the thermal properties of S. chinensis oil between $$20\,{^{\circ }}\hbox {C}$$ and $$45\,{^{\circ }}\hbox {C}$$ .

Using non-destructive photothermal techniques, it is possible to characterize non-homogenous materials to obtain its optical and thermal properties through photoacoustic spectroscopy (PAS). In photoacoustic (PA) phenomena, there are transient states of thermal excitation, when samples absorb the incident light; these states manifest an excitation process that generates the PA signal, being in direct relation with the non-radiative relaxation times with the sample absorbent centers. The objective of this study was to determine the non-radiative relaxation times associated with different absorbent centers of corn seeds (Zea mays L.), by using PAS. A frequency scan was done at different wavelengths (350 nm, 470 nm and 650 nm) in order to obtain the non-radiative relaxation times with different types of maize seeds.

Using the conventional Haberkorn approach, it is evaluated the recombination of the radical pair (RP) singlet spin state to study theoretically the cytoprotective effect of an extremely-low-frequency electromagnetic field (ELF-EMF) on early stages of hepatic cancer chemically induced in rats. The proposal is that ELF-EMF modulates the interconversion rate of singlet and triplet spin states of the RP populations modifying the products from the metabolization of carcinogens. Previously, we found that the daily treatment with ELF-EMF 120 Hz inhibited the number and area of preneoplastic lesions in chemical carcinogenesis. The singlet spin population is evaluated diagonalizing the spin density matrix through the Lanczos method in a radical pair mechanism (RPM). Using four values of the interchange energy, we have studied the variations over the singlet population. The low magnetic field effect as a test of the influence over the enzymatic chemical reaction is evaluated calculating the quantum yield. Through a bootstrap technique the range is found for the singlet decay rate for the process. Applying the quantum measurements concept, we addressed the impact toward hepatic cells. The result contributes to improving our understanding of the chemical carcinogenesis process affected by charged particles that damage the DNA.

The recent use that has been given to bio-oil as an additive, in a commercial engine oil, raises the necessity to study its physical properties. The present study is aimed to obtain thermal properties of blends made with Jatropha-Curcas L. Oil, Crude, and Refined, at different concentrations using SAE40W oil (EO) as a lubricant base. By using photothermal techniques, thermal effusivity and diffusivity were obtained. The obtained results show that thermal effusivity increases from 455 $$\hbox {Ws}^{1/2}{\cdot }\hbox {m}^{-2}{\cdot }\hbox {K}^{-1}$$ to 520 $$\hbox {Ws}^{1/2}{\cdot }\hbox {m}^{-2}{\cdot }\hbox {K}^{-1}$$ as the percentage of additive increases as well, whereas thermal diffusivity values range from $$7\times 10^{-8}\hbox {m}^{2}{\cdot }\hbox {s}^{-1}$$ to $$10\times 10^{-8}\hbox {m}^{2}{\cdot }\hbox {s}^{-1}$$ . In the present study, four balls test was used in order to obtain friction coefficient and wear scar values for studied samples, the obtained results point out that in general refined Jatropha-Curcas L. oil presents smaller wear scars than the crude one.

A knowledge about seed optical parameters is of great relevance in seed technology practice. Such parameters provide information about its absorption and reflectance, which could be useful for biostimulation processes, by light sources, in early stages of seed germination. In the present research photoacoustic spectroscopy (PAS) and the Rosencwaig and Gersho model were used to determine the optical absorption coefficient ( $$\beta $$ ) of five varieties of bean seeds (Phaseolus vulgaris L.), of different productive cycles; the seeds were biostimulated by laser treatment to evaluate the effects of biostimulation pre-sowing. It was found that the bean varieties V1, V2, V4, and V5 were optically opaque in the visible spectrum; in the case of the V3 variety, this sample was optically transparent from 680 nm. The varieties of the studied bean seeds showed significant statistical differences in sizes and also in their optical absorption spectra. The biostimulation effects showed that the seed samples with a higher optical penetration length had a positive biostimulation, in the percentage of germination, obtaining an enhancement of 47 % compared to the control sample. The utility of PAS for the optical characterization of seeds has been demonstrated in this study of the laser biostimulation process of this kind of samples.