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1.
Braz J Biol ; 84: e282664, 2024.
Article in English | MEDLINE | ID: mdl-39109724

ABSTRACT

In the last few years, there has been an increasing interest in solutions for sustainable agriculture to reduce negative impacts on the environment resulting from modern agricultural practices. The use of environmentally beneficial bacteria, like Pseudomonas, which can increase plant productivity by reducing growth time, is a promising opportunity for sustainable agriculture. Pseudomonas is a gram-negative bacterium genus, commonly present in soils, plants, and irrigation water. Pseudomonas has a wide range of metabolic routes that could benefit agriculture, such as nutrient uptake, pathogen suppression, heavy metal solubilization, drought tolerance, and high salt concentration tolerance. Pseudomonas may even be proposed as a potential tool for future agriculture on other planets, where the use of microorganisms would be essential for crop development in hostile and inhospitable environments. Hence, the present review discusses the potential use of Pseudomonas in sustainable agriculture on planet Earth and potentially on Mars, highlighting its role in plant growth enhancement and plant protection from pathogenic microorganisms.


Subject(s)
Agriculture , Pseudomonas , Pseudomonas/physiology , Soil Microbiology , Plant Development/physiology
2.
J Phys Condens Matter ; 35(35)2023 Jun 08.
Article in English | MEDLINE | ID: mdl-37253372

ABSTRACT

Barium titanate (BaTiO3) single crystal with a tetragonal phase was characterized by nanoindentation. Elastic and elastic-plastic deformation regimes were obtained. The main objective was the evaluation of the anisotropic behavior related to mechanical properties associated with the cross-section of the ferroelectrica- andc-domains (In-plane and out-of-plane) in (001) configuration domains. This behavior was evaluated along a line perpendicular to the between domains, which demonstrated that the mechanical properties of the BaTiO3single crystal depend on the distance from due to the effect of the influence of the neighbor domain. A three-dimensional (3D) finite element (FE) model was developed to simulate mechanical effects revealed by the nanoindentations test. The FE simulation demonstrated that there is no simple isotropic mechanical behavior associated with the domain type. Numerical simulations and experiments performed to study ferroelastic switching domains in BaTiO3crystals revealed the interaction of the 90°-cadomain with the indentation position.

3.
J Mech Behav Biomed Mater ; 117: 104404, 2021 05.
Article in English | MEDLINE | ID: mdl-33667799

ABSTRACT

Guided bone regeneration surgeries are based on grafting a scaffold in the site to be repaired. The main focus of the scaffold is to provide mechanical support to newly formed blood vessels and cells that will colonize the grafted site, achiving bone regenertation. In this regards, the aim of this study was to characterize the anatomy, structular, surface morphologycal, chemical composition, and nanomechanical properties of ostrich and equine trabecular bone. Ostrich and equine specimens were obtained from a local abattoir and bone was obtained by blunt dissection, n = 5. Tissue bone anatomy and trabecular structure were measured using Computerized Axial Tomography (CAT). Atomic Force Microscopy (AFM) and Energy dispersion spectrometry of X-ray (EDS) were used to examine surface morphology and chemical composition of the trabecular ostrich and equine bone. Mechanical behavior was analysted by nanoindentation. Equine specimens were examined as control. CAT results suggest that in terms of anthropometry, ostrich tarsometatarsus bone is more suitable due to its length is 432.56 ± 3.12 mm vs. the highest human bone structures reported, which femur length is 533.66 ± 18.81 mm. Besides, the low radiodensity in the Hounsfield scale exhibits equine trabecular bone more brittle (Av = 1538.4 ± 0.9) than ostrich trabecular bone (Av = 462.1 ± 1.5). EDS showed a slight variation of the element Calcium (Ca2+) ranging from 20% to 25.5% wt in equine bone; the Ca2+ content variation is consistent with the ring-shaped morphology, while in ostrich bone the chemical composition is homogeneous. The elastic modulus, nanohardness (E = 5.3 ± 0.7 GPa, H = 220 ± 10 MPa) and average roughness (Ra = 207 nm) are similar to the human trabecular bone which could reduce the stress shielding, all of these findings suggest that ostrich bone can be promising for native tissue scaffolds for mechanically demanding applications. This research makes innovative contributions to science and provides a framework, which will allow us to address future biomedical tests, and rapidly identify promising organic and sustainable waste for tissue scaffold.


Subject(s)
Bone and Bones , Cortical Bone , Animals , Biomechanical Phenomena , Bone and Bones/diagnostic imaging , Elastic Modulus , Elasticity , Horses , Microscopy, Atomic Force , Stress, Mechanical
4.
Acta odontol. venez ; 50(2)2012. ilus
Article in Spanish | LILACS | ID: lil-676719

ABSTRACT

Los Linfangiomas son considerados patologías benignas de vasos linfáticos que en la cavidad bucal se manifiestan como lesiones focales superficiales. Generalmente se presentan desde el nacimiento o antes de las dos primeras décadas de vida, aparentemente sin predilección por el sexo. Dicha lesión se manifiesta como formas vesiculares cuando son superficiales y nodulares cuando son profundas. La coloración puede variar desde un color similar al tejido circundante hasta rojo azulado cuando los capilares forman parte de la malformación. Su localización intraoral más común es la cara dorsal de la lengua y bordes laterales, pudiendo provocar macroglosia. Su presentación extraoral se denomina higroma quístico y afecta el cuello. Se reporta un caso de un paciente de sexo femenino de 24 años de edad presentando lesión tumoral elevada, multilobulada, sintomática al momento de la consulta, manifestando dolor y sangramiento espontáneo. La lesión es del mismo color de la mucosa circundante, localizada en tercio medio de la cara dorsal de la lengua, dificultando la fonación y deglución. Se realizó biopsia incisional de la lesión con un diagnóstico provisional de linfangioma, obteniendo como resultado histopatológico Linfangioma.


Linphangioma are considered as benign pathologies of the lymphatic vessels, when they are evident in the oral cavity, they become superficial focal lesions. Generally, they become present at birth or before the first two decades of human life. This injury becomes apparent in different vessels forms when is superficial and nodes when is deep. Its color can vary from a similar shade of the surrounding tissue to a bluish red when capillary vessels form part, of the malformation. Its most common intra-oral location is in the dorsal face of the tongue and side edges, where it could produce macroglossia. Its extra-oral presence is designated as cystic hygroma and it affects the neck area. This is the reported case of a 24 years old female patient, who presents an elevated tumor lesion, multilobulated, and symptomatic at the time of her medical visit, with evident pain and spontaneous bleeding. The injury shows the same color of the surrounding mucous, localized in the central zone of the dorsal face of the tongue, making it difficult for swallowing and phonation. An incision biopsy of the injury was performed, with a temporary diagnosis of linphangioma, and as a histopathologic result linphangioma.


Subject(s)
Humans , Female , Young Adult , Lymphoma , Lymphangioma/diagnosis , Lymphangioma/pathology , Mouth Neoplasms , Mouth Diseases/diagnosis , Mouth Abnormalities
5.
Rev Neurol ; 44(9): 519-23, 2007.
Article in Spanish | MEDLINE | ID: mdl-17492608

ABSTRACT

INTRODUCTION: Attention-deficit/hyperactivity disorder (ADHD) is the main neurological diagnosis in Chilean children. Its profile and evolution in adults has not been appropriately studied, despise its personal and social impact. AIM: To describe the characteristics of adults with ADHD evaluated in a memory unit, verifying the existence of differences depending on gender. PATIENTS AND METHODS: A demographic and symptomatic evaluation protocol was applied to all patients diagnosed with ADHD who consulted at the Memory Unit of the Pontificia Universidad Católica de Chile, during the year 2004. RESULTS: Eighty six patients were included. Average age was 37, being 53% male. Most patients were diagnosed for the first time in adulthood, corresponding to an ADHD of combined type. The main patients' complaints were forgetfulness and distraction. A stressing factor capable of worsening the symptoms was identified in 59% of patients. Depression was the principal comorbidity, with a significantly higher incidence in women. CONCLUSIONS: The limitations of ADHD diagnostic criteria available for adult patients are discussed. Differences depending on gender were analyzed, describing a predominantly disruptive profile in men and depressive profile in women. There is a clear under-diagnosis of female children with ADHD, with a potential negative impact on their neuropsychological development. The differential diagnosis with mild cognitive impairment, in patients complaining of recent memory decline is discussed.


Subject(s)
Attention Deficit Disorder with Hyperactivity/diagnosis , Memory/physiology , Adult , Attention Deficit Disorder with Hyperactivity/physiopathology , Child , Chile , Comorbidity , Depression/physiopathology , Female , Humans , Male , Memory Disorders/diagnosis , Memory Disorders/etiology , Middle Aged , Neuropsychological Tests , Sex Factors
6.
Horm Metab Res ; 38(12): 777-82, 2006 Dec.
Article in English | MEDLINE | ID: mdl-17163350

ABSTRACT

In the last decade many efforts have been made in order to identify brain regions that may be abnormal in obese subjects. Most of the lines of research have examined links between brain circuits, behavioral processing, and overweight. We introduce here a novel analysis to the brain mapping, 'dynamic Brain Self-Reference' (dynBSR), based on the electrical response evoked during passively viewing a simple stimulus. Hypothetically, it should be possible to monitor both task-related networks and task-irrelevant networks during a mental state with low cognitive demand, as shown previously by others using fMRI and establishing the latter as the neural correlates of an 'inherent' brain activation pattern. However, this fact has been usually ignored. Our results showed that a distinct set of interconnected brain regions including, frontal areas (middle, inferior, orbitofrontal, and dorsolateral), dorsal/ventral striatum, thalamus, superior temporal region, insula cortex, post-central gyrus, left supramarginal gyrus, and parietal regions, whose activities seem to be tonically maintained, displays cohesive functional state in obesity during passively viewing a simple stimulus. This organized network is maintained in a dynamic equilibrium with the transient activation of the right supramarginal gyrus. These brain areas have been previously implicated in the regulation of taste, reward, and behavioral processing and most of them have also structural abnormalities regarding normal-weight subjects. Although exploratory, the most important result here is that the evaluation of the visual-evoked responses with dynBSR provides a foundation for investigating the brain circuits in obesity, and becomes the first attempt, to our knowledge, to imply task-irrelevant networks in these individuals.


Subject(s)
Brain Mapping/methods , Brain/physiology , Obesity/psychology , Adult , Evoked Potentials, Visual/physiology , Humans , Imaging, Three-Dimensional
7.
Complement Ther Med ; 14(1): 31-8, 2006 Mar.
Article in English | MEDLINE | ID: mdl-16473751

ABSTRACT

OBJECTIVES: The aim of this work was to compare in vivo measurements of direct current (dc) and alternating current (ac) obtained from acupuncture points in Ukrainian and Mexican residents. METHODS: Measurements were made using the method of Voll. The participants were 43 healthy Ukrainian and 71 healthy Mexican residents aged between 20 and 30 years, as well as 24 Mexican patients with a clinical diagnosis of rheumatoid arthritis and 14 patients with a clinical diagnosis of allergy. RESULTS: The results showed that dc measurements are not directly applicable to different populations. Thus, the dc resistance of the acupuncture points in the Mexican participants was 4-5 times larger than in the Ukrainians. In contrast, the capacitance of the two groups did not differ by more than 25%. CONCLUSIONS: Impedance measurements from acupuncture points can be used as an efficient and prompt non-invasive method for diagnostic purposes.


Subject(s)
Acupuncture Points , Adult , Arthritis, Rheumatoid/physiopathology , Electric Impedance , Humans , Hypersensitivity/physiopathology , Mexico , Ukraine
8.
Med Hypotheses ; 66(2): 300-8, 2006.
Article in English | MEDLINE | ID: mdl-16199129

ABSTRACT

Molecular data and gene expression data and recently mitochondrial genes and possible epigenetic regulation by non-coding genes is revolutionizing our views on schizophrenia. Genes and epigenetic mechanisms are triggered by cell-cell interaction and by external stimuli. A number of recent clinical and molecular observations indicate that epigenetic factors may be operational in the origin of the illness. Based on the molecular insights, gene expression profiles and epigenetic regulation of gene, we went back to the neurophysiology (brain oscillations) and found a putative role of the visual experiences (i.e. visual stimuli) as epigenetic factor. The functional evidences provided here, establish a direct link between the striate and extrastriate unimodal visual cortex and the neurobiology of the schizophrenia. This result support the hypothesis that 'visual experience' has a potential role as epigenetic factor and contribute to trigger and/or to maintain the progression of the schizophrenia. In this case, candidate genes sensible for the visual 'insult' may be located within the visual cortex including associative areas, while the integrity of the visual pathway before reaching the primary visual cortex is preserved. The same effect can be perceived if target genes are localised within the visual pathway, which actually, is more sensitive for 'insult' during the early life than the cortex per se. If this process affects gene expression at these sites a stably sensory specific 'insult', i.e. distorted visual information, is entering the visual system and expanded to fronto-temporo-parietal multimodal areas even from early maturation periods. The difference in the timing of postnatal neuroanatomical events between such areas and the primary visual cortex in humans (with the formers reaching the same development landmarks later in life than the latter) is 'optimal' to establish an abnormal 'cell- communication' mediated by the visual system that may further interfere with the local physiology. In this context the strategy to search target genes need to be rearrangement and redirected to visual-related genes. Otherwise, psychophysics studies combining functional neuroimage, and electrophysiology are strongly recommended, for the search of epigenetic clues that will allow to carrier gene association studies in schizophrenia.


Subject(s)
Epigenesis, Genetic , Schizophrenia/genetics , Visual Pathways , Humans , Visual Pathways/anatomy & histology
9.
Yeast ; 21(5): 403-12, 2004 Apr 15.
Article in English | MEDLINE | ID: mdl-15116341

ABSTRACT

Debaryomyces hansenii, a halophile yeast found in shallow sea waters and salty food products grows optimally in 0.6 M of either NaCl or KCl, accumulating high concentrations of Na(+) or K(+). After growth in NaCl or KCl, a rapid efflux of either accumulated cation was observed if the cells were incubated in the presence of KCl or NaCl, respectively, accompanied by a slower accumulation of the cation present in the incubation medium. However, a similar, rapid efflux was observed if cells were incubated in buffer, in the absence of external cations. This yeast shows a cation uptake activity of both (86)Rb(+) and (22)Na(+) with saturation kinetics, and much higher affinity for (86)Rb(+) than for (22)Na(+). The pH dependence of the kinetics constants was similar for both cations, and although K(m) values were higher at pH 8.0, there was also an increase in the V(max) values. The accumulation of (22)Na(+) was found to be increased in cells grown in the presence of 0.6 M NaCl. (86)Rb(+) was also accumulated more in these cells, but to a slightly greater extent. The inhibition kinetics of the uptake of (22)Na(+) by K(+), and that of (86)Rb(+) by Na(+) was found to be non-competitive. It can be concluded that Na(+) in D. hansenii is not excluded but instead, its metabolic systems must be resistant to high salt concentrations.


Subject(s)
Potassium/metabolism , Saccharomycetales/metabolism , Sodium/metabolism , Culture Media , Hydrogen-Ion Concentration , Ion Transport , Kinetics , Models, Biological , Osmolar Concentration , Rubidium/metabolism , Saccharomycetales/growth & development
10.
Rev Neurol ; 37(12): 1107-11, 2003.
Article in Spanish | MEDLINE | ID: mdl-14691759

ABSTRACT

AIMS: The purpose of this research was to study the spatio-temporal characteristics of the correlation that exists between two simultaneous EEG signals (coherence) in the interictal period in patients with partial epilepsy that is presumably symptomatic of the temporal lobe (ILAE). PATIENTS AND METHODS: A study of 13 patients, aged between 17-60 years, was conducted (53% females). A digital EEG was performed on each patient using the 10/20 system of electrode location. 24 artifact-free segments were selected from the recording made in a rest-waking state with the patient's eyes closed. Fourier's transformation was employed to obtain cross spectrum matrices, which were then used to calculate the intrahemispheric (Cohintra) and interhemispheric (Cohinter) coherences expressed by the Z transformation. These values were ordered by regions considering the known anatomical connections. RESULTS: In both the overall and the individual analyses, we found greater alterations of the Cohintra and the Cohinter in the temporal regions, and there was a predominance of the left hemisphere. The individual analysis of coherence, unlike the visual interpretation of the EEG recording, showed significant alterations in all the patients in the sample. CONCLUSIONS: Incorporating this type of tool would enable us to reach a more accurate topographic diagnosis in cases of epilepsy of unknown aetiology. At the same time the possible means of medical and surgical treatment available would be widened.


Subject(s)
Electroencephalography , Epilepsy, Temporal Lobe/physiopathology , Adolescent , Adult , Female , Humans , Male , Middle Aged
11.
Neuroimage ; 19(4): 1655-63, 2003 Aug.
Article in English | MEDLINE | ID: mdl-12948720

ABSTRACT

Neuroimaging studies have identified regional brain dysfunctions in schizophrenia, but their dynamic consequences remain unclear. This study reports electrophysiological evaluation of medicated schizophrenic patients during performance of the Wisconsin Card Sorting Test. Using event-related potentials (ERPs), averaged after passing through several band pass filters, and source analysis with variable-resolution brain electrical tomography, cerebral sources were visualized at every latency point of the evoked potential. ERPs which differed from the control group were elicited principally in frontal, central, and parietal regions, within the delta and theta frequency ranges. Significant differences emerged at three different latencies (S1, S2, S3) in frontal/midline areas and at the anterior temporal electrode site T3 for slow potentials. The left occipitoparietal region showed significant differences within the alpha and beta 2 ranges, respectively. Medial fronto-orbital area and anterior cingulate cortex contributed to the development of the frontal ERPs and the lateral inferior frontal area to the temporal (T(3)) evoked-potential, while the precuneus/medial region generated the posterior activity recorded on the scalp. The significant intervals S1 and S3 were synchronous between the medial frontal and lateral inferior frontal region, while in the S2 interval the medial frontal areas were parallel with the precuneus/medial occipitotemporal region. A simultaneous functional imbalance between frontal subregions and posterior areas was uncovered. Here, we show for the first time an intermittent functional deficiency of specific brain areas during task-directed mentation in schizophrenia, which by its brevity is not accessible by neuroimaging methods measuring hemodynamic activity.


Subject(s)
Electroencephalography , Evoked Potentials/physiology , Frontal Lobe/physiopathology , Neuropsychological Tests , Schizophrenia/physiopathology , Adult , Attention/physiology , Brain Mapping , Computer Graphics , Discrimination Learning/physiology , Female , Gyrus Cinguli/physiopathology , Humans , Male , Nerve Net/physiopathology , Pattern Recognition, Visual/physiology , Signal Processing, Computer-Assisted , Software , Visual Cortex/physiopathology
12.
Schizophr Res ; 61(2-3): 229-33, 2003 Jun 01.
Article in English | MEDLINE | ID: mdl-12729874

ABSTRACT

There is much evidence of frontotemporal lateralized abnormalities in schizophrenia. However, the relationship has not yet been examined between performance on the Wisconsin Card Sorting Test, with supposed anterior left dominance and event-related potential (ERP) asymmetry. ERPs recorded at homologous bilateral sites were compared using statistical permutation methods. Patients had an unexpected abnormal lateralization over occipital regions, preceding slow anterior potentials. This indicates a defect in early stages of information processing, which may contribute to prevent further hemispheric lateralization during performance.


Subject(s)
Discrimination Learning/physiology , Dominance, Cerebral/physiology , Electroencephalography , Frontal Lobe/physiopathology , Neuropsychological Tests/statistics & numerical data , Occipital Lobe/physiopathology , Pattern Recognition, Visual/physiology , Schizophrenia/physiopathology , Schizophrenic Psychology , Temporal Lobe/physiopathology , Adult , Brain Mapping , Female , Humans , Male , Problem Solving/physiology , Reaction Time/physiology , Reference Values , Schizophrenia/diagnosis , Signal Processing, Computer-Assisted
13.
Int J Psychophysiol ; 48(1): 11-24, 2003 Apr.
Article in English | MEDLINE | ID: mdl-12694897

ABSTRACT

Prefrontal dysfunction has been associated with schizophrenia. Activation during Wisconsin card sorting test (WCST) is a common approach used in functional neuroimaging to address this failure. Equally, current knowledge states that oscillations are basic forms of cells-assembly communications during mental activity. Promising results were revealed in a previous study assessing healthy subjects, WCST and oscillations. However, those previous studies failed to meet the functional integration of the network during the WCST in schizophrenics, based on the induced oscillations and their distributed cortical sources. In this research, we utilized the brain electrical tomography (variable-resolution brain electromagnetic tomography) technique to accomplish this goal. Task specific delta, theta, alpha and beta-2 oscillations were induced and simultaneously synchronized over large extensions of cortex, encompassing prefrontal, temporal and posterior regions as in healthy subjects. Every frequency had a well-defined network involving a variable number of areas and sharing some of them. Oscillations at 11.5, 5.0 and 30 Hz seem to reflect an abnormal increase or decrease, being located at supplementary motor area (SMA), left occipitotemporal region (OT), and right frontotemporal subregions (RFT), respectively. Three cortical areas appeared to be critical, that may lead to difficulties either in coordinating/sequencing the input/output of the prefrontal networks-SMA, and retention of information in memory-RFT, both preceded or paralleled by a deficient visual information processing-OT.


Subject(s)
Cerebral Cortex/physiopathology , Cognition , Schizophrenia/physiopathology , Schizophrenic Psychology , Adult , Brain Mapping , Case-Control Studies , Cortical Synchronization , Electroencephalography , Frontal Lobe/physiopathology , Humans , Nerve Net , Neuropsychological Tests , Task Performance and Analysis
14.
Med Biol Eng Comput ; 40(3): 323-6, 2002 May.
Article in English | MEDLINE | ID: mdl-12195979

ABSTRACT

The aim of the work was to use impedance measurements to find the location of nerves under the human skin. In vivo impedance measurements were performed on exposed nervous and muscular tissues of rats. Similarly, the impedance measurements were also performed on the skin of six men, over the median nerve at the wrist, as well as 4-5 mm away from this location. Results obtained with rats have shown that the relative permittivity and conductivity of nerves are larger (by almost two orders of magnitude) than those observed for the muscular tissues surrounding the nerve. The results obtained on human skin in the frequency range of 20-200 kHz, when the electrodes were placed over the nerve, show lower resistance and higher capacitance than in the other areas measured. These preliminary results indicate that it may be possible to use impedance measurements to find the location of exposed nerves and also nerves under the skin.


Subject(s)
Muscle, Skeletal/physiology , Skin/innervation , Adult , Animals , Electric Impedance , Galvanic Skin Response , Humans , Male , Rats
15.
Int J Food Sci Nutr ; 53(2): 155-62, 2002 Mar.
Article in English | MEDLINE | ID: mdl-11939109

ABSTRACT

In this study the effect of calcium absorption on some physical properties and composition of rat femurs was evaluated, comparing rats fed with raw whole corn (RC), tortillas made from extruded masa with 0.25% lime content (TEWL) and without lime (TE), and nixtamal tortillas (NT). The diets were formulated to contain the same amount of protein, oil, fiber, vitamins and minerals other than calcium. In all diets 0.20% calcium was added. At the end of the trials, the femurs were extracted, weighed and measured for ash, calcium and phosphorus content, some physical dimensions, and the crystallinity percentage. The femurs of rats fed with TEWL and NT were heavier, thicker, longer and had higher calcium content. On the other hand, the force required to break the femur of rats fed on ETWL and NT was 1.25 kg greater than that required to break the femurs of rats fed with RC. Higher crystallinity percentage values were observed in the femurs of the rats fed with NT (37.66%) and TEWL (36.98%) as compared to a 30.31% value obtained with the RC.


Subject(s)
Femur/physiology , Food Handling/methods , Food, Fortified/analysis , Zea mays/chemistry , Animals , Calcium/analysis , Calcium Compounds/pharmacology , Calcium, Dietary/administration & dosage , Diet , Femur/anatomy & histology , Femur/chemistry , Male , Oxides/pharmacology , Phosphorus/analysis , Rats , Rats, Wistar , Stress, Mechanical , Weight Gain , X-Ray Diffraction
16.
Arch Latinoam Nutr ; 51(2): 187-94, 2001 Jun.
Article in Spanish | MEDLINE | ID: mdl-11678051

ABSTRACT

The corn tortilla is elaborated using corn grain masa processed by the traditional nixtamalization method, which consists of two steps: cooking and steeping. In these steps the physicochemical and structural properties are strongly affected, resulting in changes in the textural characteristics of the tortilla produced. In this work the effects of cooking and steeping time on the moisture content, amylographic profiles, crystallinity, weigh loss from masa to tortilla, starch damage, rollability, elasticity and cutting force for grain, masa and corn tortillas, were evaluated. The milling of the nixtamalized grain and the cooking of tortilla conditions were the same in all treatments. All tortillas samples showed a good rollability. The results show that the moisture content of corn grain was increased up to 42 g/100 g during the total cooking time (45 min), and it further increased to 52-53 g/100 g after when the cooked grain was steeped for 4 h. All evaluated parameters showed high correlation coefficients with the texture properties of tortillas. The starch damage was the variable with the best correlation among all evaluated parameters. The correlation coefficients between starch damage and moisture content, weigh loss and maximum viscosity for corn grain, masa and tortillas were larger than 0.92 (p < 0.01). The best tortillas were produced using nixtamal with the follow characteristics: moisture content of nixtamal, 42-44 g/100 g and tortilla, 43-44 g/100 g; adhesiveness of masa, 30-50 g; maximum viscosity of nixtamal, 860-880 cp and tortilla 490-510 cp; starch damage of nixtamal, 14 g/100 g and tortilla, 35-37 g/100 g, and weigh loss of tortilla during cooking, 16 g/100 g.


Subject(s)
Flour/analysis , Food Handling , Food Technology , Hot Temperature , Zea mays/chemistry , Food Preservation , Quality Control , Rheology
17.
Arch Latinoam Nutr ; 51(3): 293-302, 2001 Sep.
Article in Spanish | MEDLINE | ID: mdl-11791483

ABSTRACT

The effect of the addition of vitamins and soy protein on the quality characteristics of nixtamal tortillas (TN) and the losses of nutrients during the nixtamalization process were evaluated. Vitamins (0.15% as is) and defatted soy (4% as is) were added to the tortillas without affecting their sensory characteristics. Higher values of those nutrients had a negative effect on the color and flavor of the product. During the production of the tortilla the corn lost approximately 1.5% of proteins. The nixtamal tortilla fortified with 4% of defatted soy (TNS) showed 3% higher protein content than the TN. The calcium content in the samples was 7.7, 114 and 212.5 mg/100 g for the corn, the TN and the TNS respectively. In the process of producing the nixtamal tortillas from corn 28.9% of the niacin, 46.3% of the folic acid, 36.3% of the thiamin and 80% of the riboflavin were lost. During the washing and rinsing of the nixtamal there were losses of 18.2% of the thiamin, 16.6% of the riboflavin and 20.7% of the folic acid. Although the niacin showed a 28.9% loss, the alkaline process caused an important release of that vitamin. The losses during the cooking of the tortillas were high especially for riboflavin which showed a total loss of 80% in comparison with the original corn. Of the total, 63% was lost during cooking and 16.6% was lost during washing of the nixtamal.


Subject(s)
Food Handling/methods , Food, Fortified , Zea mays/chemistry , Dietary Proteins/analysis , Dietary Proteins/metabolism , Flour , Hot Temperature , Minerals/analysis , Minerals/metabolism , Nutritive Value , Quality Control , Soybean Proteins/analysis , Soybean Proteins/metabolism , Glycine max/chemistry , Glycine max/metabolism , Vitamins/analysis , Vitamins/metabolism , Zea mays/metabolism
18.
Med Biol Eng Comput ; 38(5): 507-11, 2000 Sep.
Article in English | MEDLINE | ID: mdl-11094806

ABSTRACT

The aim is to compare the mean values of the in vivo electrical characteristics of biological active points (BAPs) with those of the surrounding human skin. The impedance measurements at BAPs and on the surrounding skin are carried out in vivo on ten young, healthy people. The results of the measurements show that the BAP resistance RP is smaller, and the capacitance CP is higher, than the corresponding values for skin, RS and CS, respectively, these differences are larger at low frequencies (at f = 3 Hz, RS/RP = 3.19 and CP/CS = 3.2). The mean values of the impedance measurements at the BAPs are different from those measured on the skin. The dependence of RP and CP on the pressing force, in the range of about 1-5 N, for the BAPs, has a smaller slope than that observed for the surrounding skin. An equivalent circuit for the BAPs is proposed that describes sufficiently well the experimental results obtained. These results show that the large dispersion in the observed impedance characteristics of the human body measurements in different body regions can be related to the influence of the BAPs present under the electrodes.


Subject(s)
Galvanic Skin Response , Adolescent , Adult , Electric Impedance , Electrodes , Humans , Models, Biological
19.
Arch Latinoam Nutr ; 46(4): 315-9, 1996 Dec.
Article in Spanish | MEDLINE | ID: mdl-9429614

ABSTRACT

Chemical changes of some nutritional components (protein, total dietary fiber, vitamins, lysine, tryptophan, ether extract and fatty acids) of tortillas made from instant whole corn flour prepared by extrusion process (CINVESTAV process) were evaluated. The tortillas prepared by extrusion process were compared with tortillas made by traditional process and raw corn. The protein content of tortillas from both processes were statistically similar to those of the raw corn, although the traditional tortillas showed the lowest actual values. Tortillas from traditional process contained the lowest amount of total dietary fiber and available lysine. The loss of protein, crude fiber, total dietary fiber, available lysine, tryptophan, and vitamin contents during traditional tortillas process, was attributable to the partial loss of pericarp, aleurone and germ tissue during the process. Tortillas prepared by both processes showed loss of vitamins. The thermal treatment in both processes (traditional and extrusion) decreased the ether extract and fatty acids contents. Tortillas prepared by extrusion process showed better nutritional characteristics than traditional tortillas prepared by nixtamalization process.


Subject(s)
Flour , Food Handling/methods , Zea mays/chemistry , Nutritive Value
20.
Bol Med Hosp Infant Mex ; 37(4): 667-77, 1980.
Article in Spanish | MEDLINE | ID: mdl-6996694

ABSTRACT

In this work, we studied a group of obese children submitted to two different types of diet (ketogenic and hypocaloric) for 8 weeks and the relationship with liberation of insulin by beta cells of Langerhans islands. It was shown that in children under ketogenic diet, the drop in weight, together with the liberation of insulin, was significantly greater than in those given hypocaloric diet. The possible role of gastrointestinal hormones and opther factors related with the diet are evaluated. It is concluded that the greater reduction in body weight in patients given ketogenic diet is an important factor in the normalization of plasmatic insulin levels.


Subject(s)
Insulin/metabolism , Islets of Langerhans/metabolism , Obesity/metabolism , Adolescent , Body Weight , Child , Dietary Carbohydrates/metabolism , Dietary Carbohydrates/therapeutic use , Dietary Fats/metabolism , Dietary Fats/therapeutic use , Dietary Proteins/metabolism , Dietary Proteins/therapeutic use , Humans , Insulin Secretion , Male , Obesity/diet therapy
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