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1.
Psychophysiology ; 61(6): e14544, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38351668

ABSTRACT

Predictive coding framework posits that our brain continuously monitors changes in the environment and updates its predictive models, minimizing prediction errors to efficiently adapt to environmental demands. However, the underlying neurophysiological mechanisms of these predictive phenomena remain unclear. The present study aimed to explore the systemic neurophysiological correlates of predictive coding processes during passive and active auditory processing. Electroencephalography (EEG), functional near-infrared spectroscopy (fNIRS), and autonomic nervous system (ANS) measures were analyzed using an auditory pattern-based novelty oddball paradigm. A sample of 32 healthy subjects was recruited. The results showed shared slow evoked potentials between passive and active conditions that could be interpreted as automatic predictive processes of anticipation and updating, independent of conscious attentional effort. A dissociated topography of the cortical hemodynamic activity and distinctive evoked potentials upon auditory pattern violation were also found between both conditions, whereas only conscious perception leading to imperative responses was accompanied by phasic ANS responses. These results suggest a systemic-level hierarchical reallocation of predictive coding neural resources as a function of contextual demands in the face of sensory stimulation. Principal component analysis permitted to associate the variability of some of the recorded signals.


Subject(s)
Auditory Perception , Electroencephalography , Evoked Potentials, Auditory , Spectroscopy, Near-Infrared , Humans , Male , Female , Adult , Young Adult , Auditory Perception/physiology , Evoked Potentials, Auditory/physiology , Autonomic Nervous System/physiology , Cerebral Cortex/physiology , Anticipation, Psychological/physiology , Attention/physiology
2.
Brain Sci ; 13(11)2023 Oct 31.
Article in English | MEDLINE | ID: mdl-38002498

ABSTRACT

BACKGROUND: The present report tries to understand the possible relationship between working memory (WM) and intelligence measurements, using the direct scores of the Working Memory Test Battery for Children (WMTBC) and Kaufman's Brief Intelligence Test (K-BIT), in normal development (ND) and diagnosed attention deficit hyperactivity disorder (ADHD) children and adolescents. RESULTS: Partial correlations, discounting the effect of age, showed a significant correlation in ND subjects between the central executive (CE) component of WM and the WM visuospatial sketchpad (VSS) component and the WM phonological loop (PL); also, significant correlations were obtained for the WM VSS with the K-BIT Matrices scores, the WM PL with the K-BIT Vocabulary, and the K-BIT Matrices scores with the K-BIT Vocabulary. For ADHD subjects, there were significant correlations between WM VSS and WM CE, and WM VSS and K-BIT Matrices. We tested the robustness of these correlations by selecting a small number of subjects through permutations; a robust correlation between WM CE and WM PL in ND, and between WM VSS and WM CE and WM VSS and K-BIT Matrices scores was obtained. These results were also supported by mediation analysis. CONCLUSIONS: There is a relationship during development between WM as measured with WMTBC and general intelligence as measured with K-BIT in ND and ADHD subjects. The dysexecutive character of ADHD has been shown, given that by controlling for intelligence, the differences in WM performance between ND and ADHD disappear, except for WM CE. The results suggest that in ADHD subjects, the WM VSS component presents a more pivotal role during cognitive processing compared to ND subjects.

3.
Brain Struct Funct ; 228(8): 1943-1961, 2023 Nov.
Article in English | MEDLINE | ID: mdl-37658858

ABSTRACT

Intensity-dependent amplitude changes (IDAP) have been extensively studied using event-related potentials (ERPs) and have been linked to several psychiatric disorders. This study aims to explore the application of functional near-infrared spectroscopy (fNIRS) in IDAP paradigms, which related to ERPs could indicate the existence of neurovascular coupling. Thirty-three and thirty-one subjects participated in two experiments, respectively. The first experiment consisted of the presentation of three-tone intensities (77.9 dB, 84.5 dB, and 89.5 dB) lasting 500 ms, each type randomly presented 54 times, while the second experiment consisted of the presentation of five-tone intensities (70.9 dB, 77.9 dB, 84.5 dB, 89.5 dB, and 94.5 dB) in trains of 8 tones lasting 70 ms each tone, the trains were presented 20 times. EEG was used to measure ERP components: N1, P2, and N1-P2 peak-to-peak amplitude. fNIRS allowed the analysis of the hemodynamic activity in the auditory, visual, and prefrontal cortices. The results showed an increase in N1, P2, and N1-P2 peak-to-peak amplitude with auditory intensity. Similarly, oxyhemoglobin and deoxyhemoglobin concentrations showed amplitude increases and decreases, respectively, with auditory intensity in the auditory and prefrontal cortices. Spearman correlation analysis showed a relationship between the left auditory cortex with N1 amplitude, and the right dorsolateral cortex with P2 amplitude, specifically for deoxyhemoglobin concentrations. These findings suggest that there is a brain response to auditory intensity changes that can be obtained by EEG and fNIRS, supporting the neurovascular coupling process. Overall, this study enhances our understanding of fNIRS application in auditory paradigms and highlights its potential as a complementary technique to ERPs.


Subject(s)
Auditory Cortex , Neurovascular Coupling , Humans , Acoustic Stimulation , Hemodynamics , Evoked Potentials
4.
Cogn Neurodyn ; 17(4): 869-891, 2023 Aug.
Article in English | MEDLINE | ID: mdl-37522046

ABSTRACT

This present study aims to investigate neural mechanisms underlying ADHD compared to healthy children through the analysis of the complexity and the variability of the EEG brain signal using multiscale entropy (MSE), EEG signal standard deviation (SDs), as well as the mean, standard deviation (SDp) and coefficient of variation (CV) of absolute spectral power (PSD). For this purpose, a sample of children diagnosed with attention-deficit/hyperactivity disorder (ADHD) between 6 and 17 years old were selected based on the number of trials and diagnostic agreement, 32 for the open-eyes (OE) experimental condition and 25 children for the close-eyes (CE) experimental condition. Healthy control subjects were age- and gender-matched with the ADHD group. The MSE and SDs of resting-state EEG activity were calculated on 34 time scales using a coarse-grained procedure. In addition, the PSD was averaged in delta, theta, alpha, and beta frequency bands, and its mean, SDp, and CV were calculated. The results show that the MSE changes with age during development, increases as the number of scales increases and has a higher amplitude in controls than in ADHD. The absolute PSD results show CV differences between subjects in low and beta frequency bands, with higher variability values in the ADHD group. All these results suggest an increased EEG variability and reduced complexity in ADHD compared to controls. Supplementary Information: The online version contains supplementary material available at 10.1007/s11571-022-09869-0.

5.
Brain Cogn ; 167: 105969, 2023 04.
Article in English | MEDLINE | ID: mdl-36958141

ABSTRACT

The developmental trajectories of brain oscillations during the encoding and maintenance phases of a Working Memory (WM) task were calculated. The Delayed-Match-to-Sample Test (DMTS) was applied to 239 subjects of 6-29 years, while EEG was recorded. The Event-Related Spectral Perturbation (ERSP) was obtained in the range between 1 and 25 Hz during the encoding and maintenance phases. Behavioral parameters of reaction times (RTs) and response accuracy were simultaneously recorded. The results indicate a myriad of transient and sustained bursts of oscillatory activity from low frequencies (1 Hz) to the beta range (up to 19 Hz). Beta and Low-frequency ERSP increases were prominent in the encoding phase in all age groups, while low-frequency ERSP indexed the maintenance phase only in children and adolescents, but not in late adolescents and young adults, suggesting an age-dependent neural mechanism of stimulus trace maintenance. While the latter group showed Beta and Alpha indices of anticipatory attention for the retrieval phase. Mediation analysis showed an important role of early Delta-Theta and late Alpha oscillations for mediation between age and behavioral responses performance. In conclusion, the results show a complex pattern of oscillatory bursts during the encoding and maintenance phases with a consistent pattern of developmental changes.


Subject(s)
Adolescent Development , Memory, Short-Term , Young Adult , Adolescent , Humans , Child , Memory, Short-Term/physiology , Electroencephalography , Brain/physiology , Reaction Time
6.
J Fluoresc ; 33(5): 1803-1812, 2023 Sep.
Article in English | MEDLINE | ID: mdl-36826728

ABSTRACT

A new methodology based on the fluorescence of Cu(II) ternary system with o-phenanthroline (o-Phen) and eosin (Eo) dyes is proposed. The metal was selectively retained on Nylon membranes and the solid surface fluorescence (SSF) was used for anayte quantification. Experimental variables that influence the formation of Cu(II)-o-Phen-eo system and retention step were studied and optimized. At optimal experimental conditions, an adequate tolerance to foreign species was shown with a LOD of 1.18 ng L-1 and a LOQ of 3.57 ng L-1. The methodology was evaluated for their greenness profile and successfully applied to analyte determination in bee's products of West-Center Argentina. Recovery studies showed values near to 100% being satisfactorily validated by ICP-MS.


Subject(s)
Copper , Phenanthrolines , Bees , Animals , Spectrometry, Fluorescence/methods , Eosine Yellowish-(YS)
7.
Physiol Rep ; 10(13): e15372, 2022 07.
Article in English | MEDLINE | ID: mdl-35785451

ABSTRACT

The present study aims to analyze the systemic response to auditory stimulation by means of hemodynamic (cephalic and peripheral) and autonomic responses in a broad range of auditory intensities (70.9, 77.9, 84.5, 89.5, 94.5 dBA). This approach could help to understand the possible influence of the autonomic nervous system on the cephalic blood flow. Twenty-five subjects were exposed to auditory stimulation while electrodermal activity (EDA), photoplethysmography (PPG), electrocardiogram, and functional near-infrared spectroscopy signals were recorded. Seven trials with 20 individual tones, each for the five intensities, were presented. The results showed a differentiated response to the higher intensity (94.5 dBA) with a decrease in some peripheral signals such as the heart rate (HR), the pulse signal, the pulse transit time (PTT), an increase of the LFnu power in PPG, and at the head level a decrease in oxygenated and total hemoglobin concentration. After the regression of the visual channel activity from the auditory channels, a decrease in deoxyhemoglobin in the auditory cortex was obtained, indicating a likely active response at the highest intensity. Nevertheless, other measures, such as EDA (Phasic and Tonic), and heart rate variability (Frequency and time domain) showed no significant differences between intensities. Altogether, these results suggest a systemic and complex response to high-intensity auditory stimuli. The results obtained in the decrease of the PTT and the increase in LFnu power of PPG suggest a possible vasoconstriction reflex by a sympathetic control of vascular tone, which could be related to the decrease in blood oxygenation at the head level.


Subject(s)
Auditory Cortex , Hemodynamics , Acoustic Stimulation , Auditory Cortex/physiology , Heart Rate/physiology , Humans , Photoplethysmography/methods
8.
Cogn Neurodyn ; 16(3): 591-608, 2022 Jun.
Article in English | MEDLINE | ID: mdl-35603049

ABSTRACT

The ubiquitous brain oscillations occur in bursts of oscillatory activity. The present report tries to define the statistical characteristics of electroencephalographical (EEG) bursts of oscillatory activity during resting state in humans to define (i) the statistical properties of amplitude and duration of oscillatory bursts, (ii) its possible correlation, (iii) its frequency content, and (iv) the presence or not of a fixed threshold to trigger an oscillatory burst. The open eyes EEG recordings of five subjects with no artifacts were selected from a sample of 40 subjects. The recordings were filtered in frequency ranges of 2 Hz wide from 1 to 99 Hz. The analytic Hilbert transform was computed to obtain the amplitude envelopes of oscillatory bursts. The criteria of thresholding and a minimum of three cycles to define an oscillatory burst were imposed. Amplitude and duration parameters were extracted and they showed durations between hundreds of milliseconds and a few seconds, and peak amplitudes showed a unimodal distribution. Both parameters were positively correlated and the oscillatory burst durations were explained by a linear model with the terms peak amplitude and peak amplitude of amplitude envelope time derivative. The frequency content of the amplitude envelope was contained in the 0-2 Hz range. The results suggest the presence of amplitude modulated continuous oscillations in the human EEG during the resting conditions in a broad frequency range, with durations in the range of few seconds and modulated positively by amplitude and negatively by the time derivative of the amplitude envelope suggesting activation-inhibition dynamics. This macroscopic oscillatory network behavior is less pronounced in the low-frequency range (1-3 Hz).

9.
Exp Physiol ; 106(4): 1072-1098, 2021 04.
Article in English | MEDLINE | ID: mdl-33624899

ABSTRACT

NEW FINDINGS: What is the central question of this study? Auditory stimulation produces a response in different physiological systems: cardiac, peripheral blood flow, electrodermal, cortical and peripheral haemodynamic responses and auditory event-related potentials. Do all these subsystems covary when responding to auditory stimulation, suggesting a unified locus of control, or do they not covary, suggesting independent loci of control for these physiological responses? What is the main finding and its importance? Auditory sensory gating reached a fixed level of neural activity independently of the intensity of auditory stimulation. The use of multivariate techniques revealed the presence of different regulatory mechanisms for the different physiologically recorded signals. ABSTRACT: We studied the effects of an increasing amplitude of auditory stimulation on a variety of autonomic and CNS responses and their possible interdependence. The subjects were stimulated with an increasing amplitude of auditory tones while the auditory event-related potentials (ERPs), the cortical and extracerebral functional near-infrared spectroscopy (fNIRS) signal of standard and short separation channel recordings, the peripheral pulse measured by photoplethysmography, heart rate and electrodermal responses were recorded. Trials with eight tones of equal amplitude were presented. The results showed a parallel increase of activity in ERPs, fNIRS and peripheral responses with the increase in intensity of auditory stimulation. The ERPs, measured as peak-to-peak N1-P2, showed an increase in amplitude with auditory stimulation and a high attenuation from the first presentation with respect to the second to eighth presentations. Peripheral signals and standard and short channel fNIRS responses showed a decrease in amplitude in the high-intensity auditory stimulation conditions. Principal components analysis showed independent sources of variance for the recorded signals, suggesting independent control of the recorded physiological responses. The present results suggest a complex response associated to the increase of auditory stimulation with a fixed amplitude for ERPs, and a decrease in the peripheral and cortical haemodynamic response, possibly mediated by activation of the sympathetic nervous system, constituting a defensive reflex to excessive auditory stimulation.


Subject(s)
Electroencephalography , Evoked Potentials, Auditory , Acoustic Stimulation , Autonomic Nervous System/physiology , Electroencephalography/methods , Evoked Potentials, Auditory/physiology , Humans , Multivariate Analysis
10.
Neurosci Lett ; 749: 135747, 2021 04 01.
Article in English | MEDLINE | ID: mdl-33610662

ABSTRACT

The present report aimed to analyze the possible relationship of spontaneous EEG power variability across epochs in individual subjects (absolute and relative) with age. For this purpose, the resting state EEG of a sample of 258 healthy subjects (6-29 years old) in open and closed eyes experimental conditions were recorded. The power spectral density (PSD) was calculated from 0.5-45 Hz. Three electrodes with the highest PSD in each band were selected, and linear and inverse regression of the mean, standard deviation (SD), and coefficient of variation CV of the PSD vs age were computed. The results showed that the EEG absolute variability (SD) decreases with age, and in contrast, the relative variability (CV) increased, except for high frequencies in which it remains stable during maturation. We conclude that the variability in the EEG PSD when is not influenced by the mean PSD tends to increase from childhood and adolescence to young adulthood. Present results complement the extensive literature on changes of EEG power in different brain rhythms with the changes in EEG power variability during maturation.


Subject(s)
Brain Mapping , Brain/physiology , Rest/physiology , Adolescent , Adult , Age Factors , Behavior/physiology , Child , Electroencephalography/methods , Female , Humans , Male , Periodicity , Young Adult
11.
Photochem Photobiol ; 96(5): 1005-1013, 2020 09.
Article in English | MEDLINE | ID: mdl-32220075

ABSTRACT

Essential oils are a mixture of volatile compounds, products of the secondary metabolism of plants. Once extracted, they can be deteriorated losing their organoleptic and therapeutic properties due to various environmental factors, being light exposure in aerobic conditions the main cause. In this work, the oregano essential oil extraction and characterization from Origanum vulgare plants grown in the experimental field of the FTU-UNSL and its photodegradation in MeOH:H2 O 60:40 v/v solvent were studied. Characterization by EIMS and NIST Mass Spectrometry indicates the main compounds of oregano essential oil, quantified in the extracted oil by GC-MS, are carvacrol (7.14%) and thymol (47.37%). Degradation of essential oil and its two major components can be caused by reactive oxygen species photogenerated from endogenous sensitizers as riboflavin. Our results suggest degradation occurs involving singlet molecular oxygen. Interaction of carvacrol and thymol with singlet oxygen is mainly a physical process, while essential oil has an important reactive component, which indicates there might be other constituents which could contribute to reactive photoprotection. The effect of simultaneous presence of oregano essential oil and tryptophan amino acid-used as a photooxidizable model under riboflavin-photosensitizing conditions-was studied in order to evaluate the possible photoprotection exerted by the essential oil.


Subject(s)
Light , Oils, Volatile/chemistry , Origanum/chemistry , Plant Oils/chemistry , Singlet Oxygen/chemistry , Cymenes/analysis , Gas Chromatography-Mass Spectrometry , Photolysis , Radiation-Protective Agents/chemistry , Spectrophotometry, Ultraviolet , Thymol/analysis
12.
Photochem Photobiol ; 96(4): 815-825, 2020 07.
Article in English | MEDLINE | ID: mdl-31912514

ABSTRACT

In this work, the flavonol fisetin was selected in order to study its reactivity against Cu(II), a metal ion of interest in biological media and industry. The stoichiometry and apparent formation constant of the complex in ethanolic medium at 25°C were evaluated using spectrophotometric techniques. The resulting stoichiometry was a 1:1 ligand:metal complex, and a log K = 5.17 ± 0.12 was determined. Since two possible chelation sites can be proposed for the complex formation, quantum chemistry calculations were performed on these structures. Calculations suggest that the hydroxyl-keto site is more stable for the complex formation than the catechol site. Flavonoids could exert protection against oxidative damage caused by reactive oxygen species, and this biological activity could be affected by chelation with metal ions. This led us to perform a study on the interaction of both, free flavonoid and complex, with reactive oxygen species. Our results showed both compounds quench molecular singlet oxygen photogenerated with visible light, mainly in a physical fashion. In order to analyze a possible protective effect of flavonoid and its complex against oxidative damage in biological environments, the amino acid tryptophan was selected as a model oxidation system. Free flavonoid does not have a marked protective effect, whereas its complex showed a relevant protective effect.

13.
Talanta ; 207: 120345, 2020 Jan 15.
Article in English | MEDLINE | ID: mdl-31594585

ABSTRACT

Nonsteroidal anti-inflammatory agents (NSAIDs) are a group of pharmaceuticals considered one of the most popular drugs used in clinical practice applied to the treatment of acute and chronic conditions. Some pharmaceuticals products are excreted reaching the environment and altering the balance of ecosystems. This work proposes a new fluorimetric flow injection (FI) methodology for the NSAID tolfenamic acid quantification based on the quenching effect of the analyte on fluorescent signal of bovine serum albumin fluorophore. Results put in evidence a mechanism of static quenching, with a Stern Volmer constant value of 1.8 × 107 L mol-1. To achieve the selective on-line preconcentration of analyte, a carbon nanotubes mini column was introduced in the FI configuration producing a beneficial effect on high sampling frequency, minimum sample and reagents consumption. The experimental factors that influence batch fluorescent signal and FI analysis have been studied and optimized. At optimal experimental conditions, an adequate tolerance to foreign species was shown. With the flow configuration, a LOD of 0.019 µg L-1, a LOQ of 0.058 µg L-1 were obtained with a sampling rate of 30 samples h-1. The new methodology was successfully applied to analyte determination in tap water and pharmaceutical and factory waste samples with recuperation near to 100%.

14.
Food Chem ; 298: 125049, 2019 Nov 15.
Article in English | MEDLINE | ID: mdl-31260998

ABSTRACT

Heavy traces metals may be present in honey being their detection very important for the quality control and it also serves as an indicator of environmental pollution. A new methodology for lead traces determination has been developed based on the quenching effect of the metal on fluorescent emission of 8-hydroxyquinoline and o-phenanthroline at λem = 360 nm (λexc = 250 nm). Experimental variables that influence on fluorimetric sensitivity were optimized by uni-variation assays. The calibration graph using zeroth order regression was linear from 0.105 µg L-1 to 51.8 µg L-1, with correlation coefficient better than 0.998. Under the optimal conditions, the limits of detection and quantification were of 0.035 µg L-1 and 0.105 µg L-1, respectively. The trueness of the methodology was assessed trough parallel samples analysis by ICP-MS. The proposed method showed good sensitivity, adequate selectivity with good tolerance to foreign ions, and was applied to the determination of lead trace amounts in honey from San Luis city (Argentina) with satisfactory results.


Subject(s)
Fluorometry/methods , Lead/analysis , Cross-Sectional Studies , Honey/analysis , Hydrogen-Ion Concentration , Limit of Detection , Oxyquinoline/chemistry , Phenanthrolines/chemistry , Reproducibility of Results
15.
J Photochem Photobiol B ; 162: 597-603, 2016 Sep.
Article in English | MEDLINE | ID: mdl-27479840

ABSTRACT

Visible-light irradiation of aqueous-ethanolic solutions of Riboflavin (Rf) in the individual presence of the flavone chrysin (Chr) and its complex with Cu(2+) ([Chr2Cu]; 2:1 L:M) generates singlet molecular oxygen O2((1)Δg), that concomitantly interact with both flavone derivatives. Overall (kt) and reactive (kr) rate constants in the order of 10(7)M(-1)s(-1) were determined for the process. Metal chelation greatly enhances the scavenging ability of [Chr2Cu] towards O2((1)Δg) through a mechanism dominated, in >80%, by the physical component. In this way, practically all O2((1)Δg) is deactivated by the complex without significant loss of the quencher. The isolated flavone quenches O2((1)Δg) in a prevailing reactive fashion. The very low value exhibited by [Chr2Cu] for the kr/kt ratio constitutes a positive quality for antioxidative protectors in biological media, where elevated local concentration and high reactivity of significant molecules make them initial targets for O2((1)Δg) aggression. Finally, two interesting properties in the field of free radicals scavenging by [Chr2Cu] must be mentioned. In first place metal chelation itself, in the obvious sense of free metal ion withdrawal from the oxidizable medium, prevents the initiation of a free radical-mediated oxidation processes through mechanisms of Fenton or lipid peroxidation. In addition, the incorporation of Cu adds to [Chr2Cu] the ability of a free radical scavenger, already described for similar Cu-chelate compounds. This collection of beneficial properties positions the complex as a remarkably promising bioprotector towards ROS-mediated oxidation. A quantification of the efficiency on the initial anti-oxidative effect exerted by Chr and [Chr2Cu] towards tryptophan was carried out. The amino acid is an archetypal molecular model, commonly employed to monitor oxidative degradation of proteinaceous media. It was efficiently photoprotected against O2((1)Δg)-mediated photooxidation by [Chr2Cu].


Subject(s)
Coordination Complexes/chemistry , Copper/chemistry , Flavonoids/chemistry , Singlet Oxygen/chemistry , Lasers , Oxidation-Reduction , Photolysis/radiation effects , Reactive Oxygen Species/chemistry , Riboflavin/chemistry , Spectrophotometry, Ultraviolet
16.
J Photochem Photobiol B ; 153: 233-9, 2015 Dec.
Article in English | MEDLINE | ID: mdl-26453988

ABSTRACT

The profusely employed drugs Piroxicam (Piro), Tenoxicam (Teno) and Meloxicam (Melo) belonging to the non-steroidal antiinflammatory drug (NSAID) family of the Oxicams (Oxis) were studied in the frame of two specific conditions: (a) their ROS scavenging ability, in relation to a possible biological antioxidant action and (b) their photodegradability under environmental conditions, in the context of Oxi-contaminated waters. Singlet molecular oxygen (O2((1)Δg)) and superoxide radical anion (O2(-)) were photogenerated through Riboflavin (Rf, vitamin B2)-photosensitization in aqueous and aqueous-methanolic solutions in the presence of Oxi concentrations in the range 50-500 µM. The visible-light absorber vitamin is currently present in all types of natural waters and constitutes the most frequent endogenous photosensitizer in mammals. Hence, it was employed in order to mimic both natural sceneries of interest. All three Oxis quench O2((1)Δg) with rate constants in the order of 10(8)M(-1)s(-1) showing a significant photodegradation efficiency given by a dominant reactive fashion for deactivation of the oxidative species. Although this is not a desirable property in the context of photoprotection upon prolonged photoirradiation, constitutes in fact a promissory aspect for the degradation NSAIDs, in waste waters. Indirect evidence indicates that Melo is also oxidized through a O2(-)-mediated component. The simultaneous presence of Piro plus tryptophan or tyrosine under Rf-photosensitizing conditions, which has taken the amino acids as photooxidizable model residues in a proteinaceous environment, indicates that the NSAID induces a protection of the biomolecules against photodynamic degradation.


Subject(s)
Free Radical Scavengers/chemistry , Piroxicam/analogs & derivatives , Piroxicam/chemistry , Reactive Oxygen Species/chemistry , Thiazines/chemistry , Thiazoles/chemistry , Anti-Inflammatory Agents, Non-Steroidal/chemistry , Light , Meloxicam , Oxidation-Reduction , Photolysis/radiation effects , Pyridines/chemistry , Rhodamines/chemistry , Riboflavin/chemistry , Singlet Oxygen/chemistry , Superoxides/chemistry , Tryptophan/chemistry , Tyrosine/chemistry , Water Pollutants, Chemical/chemistry
17.
Photochem Photobiol ; 90(6): 1251-6, 2014.
Article in English | MEDLINE | ID: mdl-25244633

ABSTRACT

The known O2((1)∆g)-sensitizer system Chitosan bounded Rose Bengal (CH-RB), with Rose Bengal (RB) immobilized by irreversible covalent bonding to the polymer Chitosan (CH), soluble in aquous acidic medium, was employed in the photodegradation of three tri-hydroxy benzene water-contaminants (THBs). The system sensitizes the O2((1)∆g)-mediated photodegradation of THBs by a process kinetically favored, as compared to that employing free RB dissolved in the same solvent. Additionally the free xanthene dye, degradable by O2((1)∆g) through self-sensitization upon prolonged light-exposure, is considerably protected when bonded to CH-polymer. The polymeric sensitizer, totally insoluble in neutral medium, can be removed from the solution after the photodegradative cycle by precipitation through a simple pH change. This fact constitutes an interesting aspect in the context of photoremediation of confined polluted waters. In other words, the sensitizing system could be useful for avoiding to dissolve dyestuffs in the polluted waters, in order to act as conventional sunlight-absorbing dye-sensitizers. In parallel the interaction CH-O2((1)∆g) in acidic solution was evaluated. The polymer quenches the oxidative species with a rate constant 2.4 × 10(8) M(-1) s(-1) being the process mostly attributable to a physical interaction. This fact promotes the photoprotection of the bonded dye in the CH-RB polymer.


Subject(s)
Chitosan/chemistry , Photochemical Processes , Photosensitizing Agents/chemistry , Polymers/chemistry , Water Pollutants, Chemical/chemistry , Hydroxylation , Oxidation-Reduction , Solubility
18.
Metas enferm ; 16(4): 73-76, mayo 2013. tab
Article in Spanish | IBECS | ID: ibc-113758

ABSTRACT

Cada vez es más frecuente la necesidad de dietas especiales en los comedores escolares, ya sea por motivos religiosos, intolerancias y/o alergias a determinados alimentos y otros problemas de salud. Por otro lado, las consecuencias de unos hábitos alimentarios inapropiados en la infancia pueden proyectarse a lo largo de toda la existencia, afectar a la calidad de vida del individuo y favorecer el desarrollo de enfermedades. En el presente artículo, octavo de una serie de nueve en los que se abordan distintos temas para dar a conocer el perfil emergente de las enfermeras en el ámbito educativo, se explican las necesidades nutricionales de los escolares en las distintas edades y qué hacer para cubrirlas; también se citan los distintos menús, atendiendo a las distintas necesidades dietéticas de los alumnos con respecto a su enfermedad, sin dejar de lado la problemática que existe en algunos centros educativos con respecto a la elaboración de las comidas y la asistencia al comedor escolar de los niños con necesidades educativas especiales. Por último, se habla de los representantes del comedor escolar y su normativa (AU)


The need for special diets in school dining rooms has become increasingly frequent, either due to religious reasons, intolerances and/or allergies to certain foods, or other health conditions. On the other hand, the consequences of an inadequate alimentary behaviour during childhood may have life-long consequences, as well as affect the individual’s quality of life, and cause the development of diseases. In the present article, the eighth in a series of nine articles in which different topics are addressed in order to make public the emerging profile of nurses in the educational setting, the nutritional needs of schoolchildren are explained according to ages, as well as what must be done in order to cover said needs. Different menus are also mentioned, addressing those different dietetic needs of pupils depending on their disease, without disregarding the problems in some educational centers in terms of food preparation and the attendance to the school dining room of children with special educational needs. Finally, the school diningroom representatives and their regulations are discussed (AU)


Subject(s)
Humans , Male , Female , Child , Collective Feeding , Child Nutrition , Feeding Behavior , Nutritional Requirements , School Health Services , School Nursing/methods , Child Nutrition Disorders/diet therapy , Disease Prevention
19.
Metas enferm ; 15(10): 73-77, dic. 2012. ilus
Article in Spanish | IBECS | ID: ibc-106442

ABSTRACT

En los centros escolares la actividad asistencial es intensa y la enfermera escolar debe actuar en todas las situaciones que puedan surgir. Los alumnos acuden a la consulta de Enfermería por distintos problemas de salud, que pueden ser agudos o no, y tienen que resolverse al momento. El papel de la enfermera escolar es formar a la comunidad educativa para que conozca los riesgos de los posibles accidentes, de cómo prevenirlos y cómo actuar de manera correcta en estos casos y también si suceden complicaciones en alumnos con patología crónica. El presente artículo está centrado en dar a conocer las urgencias escolares más frecuentes en el ámbito educativo y otras consultas que se producen en una consulta de Enfermería Escolar. Es el cuarto artículo de una serie de nueve en los que se abordan distintos temas para dar a conocer el perfil emergente de las enfermeras en el ámbito educativo (AU)


In schools care activity is intense and the school nurse should act in all situations that may arise. Students present to the School Nurse s Office for various health problems, which may be acute or not and should be resolved at the time. The role of the school nurse is to educate the school community to knowthe risks of possible accidents, how to prevent them and how to act properly in such cases and also if complications occur in children with chronic disease. This article focused on informing about the most commonly school emergencies occurring frequently in the education setting and other consultations that occur in a Consultation School Nurse s Office. This is the fourth article of a series of nine that addresses various issues to raise thee merging profile of nurses in education (AU)


Subject(s)
Humans , Male , Female , Child , School Nursing/statistics & numerical data , Emergency Treatment/statistics & numerical data , Accidents/statistics & numerical data , Nursing Care/statistics & numerical data
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