RESUMEN
This study aimed to compare socket repair with Nylon 5-0 suture and closure using cyanoacrylate biological glue after tooth extraction. Twenty male Wistar rats, each weighing approximately 200 g were submitted to the extraction of the right and left first molar teeth. On the right side, the alveolus was closed with 2 ethyl-cyanoacrylate glue, whereas on the left side closure was with a single interrupted Nylon 5-0 suture (Ethilon). The animals were sacrificed after 3, 7, 15, and 30 postoperative days, and images of histological sections of the alveolus were captured for analysis. Histomorphometry was performed using Image J software to quantify bone neoformation in the alveolus. The results showed that on the seventh postoperative day the side treated with 2-ethyl-cyanoacrylate presented a delay in relation to the sutured side. However, on days 15 and 30, the difference in bone neoformation between gradually decreased until the thirtieth postoperative day, with no significant difference in bone neoformation in the last period of analysis. There was no difference between neoformation in the two sides (p = 0.902) after statistical analysis of the histomorphometric results. In conclusion, socket repair after alveolus closure with 2-ethyl-cyanoacrylate allows complete bone neoformation after tooth extraction, and there is no significant difference when compared with closure with Nylon 5-0.
Asunto(s)
Cianoacrilatos , Nylons , Animales , Cianoacrilatos/uso terapéutico , Humanos , Masculino , Ratas , Ratas Wistar , Suturas , Alveolo Dental/cirugíaRESUMEN
The construction of reservoirs is a common practice in the world. These systems modify the hydric landscape and alter the flow of rivers, becoming lotic environments in lentic. Here we investigated the structure and spatial distribution of rotifers along a tropical reservoir. We sampled four points in the Pedra do Cavalo Reservoir, Bahia, Brazil, bimonthly, between August 2014 and June 2015. We registered more than 70 taxa distributed in 17 families, with the majority of species belonging to the Lecanidae, Brachionidae and Trichocercidae families. The species rarefaction curve did not achieve a total asymptote, indicating that species richness in the reservoir is higher than what was registered. Based in the species frequency of occurrence, we identified 48 rare species, 16 common species, five constant species and one frequent species. The highest beta diversity values were registered in riverine P1 (0.513) and intermediate P2 (0.503), although there were no significant differences between the sampling points. Despite the high abundance values in P1, P2 and P3 no significant differences were found between the studied points. Thus, this study substantially increases the knowledge on the rotifer community in the Paraguaçu River and contributes to future studies that focus on biodiversity, ecology and conservation in the Brazilian reservoir ecosystems.
Asunto(s)
Ecosistema , Ríos , Animales , Biodiversidad , Brasil , Humanos , Densidad de Población , Estaciones del AñoRESUMEN
The construction of reservoirs is a common practice in the world. These systems modify the hydric landscape and alter the flow of rivers, becoming lotic environments in lentic. Here we investigated the structure and spatial distribution of rotifers along a tropical reservoir. We sampled four points in the Pedra do Cavalo Reservoir, Bahia, Brazil, bimonthly, between August 2014 and June 2015. We registered more than 70 taxa distributed in 17 families, with the majority of species belonging to the Lecanidae, Brachionidae and Trichocercidae families. The species rarefaction curve did not achieve a total asymptote, indicating that species richness in the reservoir is higher than what was registered. Based in the species frequency of occurrence, we identified 48 rare species, 16 common species, five constant species and one frequent species. The highest beta diversity values were registered in riverine P1 (0.513) and intermediate P2 (0.503), although there were no significant differences between the sampling points. Despite the high abundance values in P1, P2 and P3 no significant differences were found between the studied points. Thus, this study substantially increases the knowledge on the rotifer community in the Paraguaçu River and contributes to future studies that focus on biodiversity, ecology and conservation in the Brazilian reservoir ecosystems.
A construção de reservatórios é uma prática comum no mundo. Esses sistemas modificam a paisagem hídrica e alteram o fluxo dos rios, tornando-se ambientes lóticos em lênticos. Aqui investigamos a estrutura e distribuição espacial de rotíferos ao longo de um reservatório tropical. Foram amostrados quatro pontos no Reservatório da Pedra do Cavalo, Bahia, Brasil, bimestralmente, entre agosto de 2014 e junho de 2015. Registramos mais de 70 táxons distribuídos em 17 famílias, com a maioria das espécies pertencentes às famílias Lecanidae, Brachionidae e Trichocercidae. A curva de rarefação das espécies não alcançou uma assíntota total, indicando que a riqueza de espécies no reservatório é superior à registrada. Com base na frequência de ocorrência das espécies, identificamos 48 espécies raras, 16 espécies comuns, cinco espécies constantes e uma espécie frequente. Os maiores valores de diversidade beta foram registrados no ribeirinho P1 (0,513) e no intermediário P2 (0,503), embora não houvesse diferenças significativas entre os pontos de amostragem. Apesar dos altos valores de abundância em P1, P2 e P3, não foram encontradas diferenças significativas entre os pontos estudados. Assim, este estudo aumenta substancialmente o conhecimento sobre a comunidade de rotíferos no rio Paraguaçu e contribui para estudos futuros que enfocam biodiversidade, ecologia e conservação nos ecossistemas de reservatórios brasileiros.
Asunto(s)
Animales , Rotíferos/clasificación , Reservorios de Agua/análisis , Ecosistema , Biodiversidad , Estaciones del Año , Brasil , Densidad de Población , RíosRESUMEN
The tongue plays an important role in oral functions. Reduced tongue strength is often noted among children with mouth-breathing behaviour. The purposes of this study were to measure the tongue pressure in children with mouth-breathing behaviour, to compare these values to those of children with nasal-breathing behaviour and to analyse the relationship between age and tongue pressure in children with a mouth-breathing pattern and in children with a nasal-breathing pattern. In this cross-sectional analytical observational study, we enroled 40 children aged 5-12 years who either exhibited mouth-breathing behaviour (n = 20) or nasal-breathing behaviour (gender- and age-matched [±2 years] controls; n = 20). Tongue pressure was evaluated using the Iowa Oral Performance Instrument; 3 measurements were recorded for each participant, with a 30-seconds rest interval. The average tongue pressure in the mouth-breathing group was lower than that in the nasal-breathing group. There was no difference in tongue pressure between genders. There was a strong and direct correlation between tongue pressure and age in the nasal-breathing group. The breathing pattern impacts tongue pressure development.
Asunto(s)
Respiración por la Boca/fisiopatología , Paladar Duro/fisiología , Lengua/fisiología , Niño , Estudios Transversales , Electromiografía , Femenino , Humanos , Masculino , PresiónRESUMEN
In this work, tris(phenantroline)ruthenium(II) chloride (Ru(phen)3) was immobilized in silica nanoparticles prepared according to the Stöber method. Efforts were devoted on the optimization of the nano-thermometer in terms of size, polydispersity, intensity of the emission and temperature sensitivity. In particular, the immobilization of the luminophore in an external thin shell made of silica grown in a second step on bare silica nanoparticles allowed producing fluorescent monodisperse silica nanoparticles (420±20nm). A systematic study was addressed to maximize the intensity of the emission of the fluorescent nanoparticles by adjusting the concentration of Ru(phen)32+ in the shell from 0.2 to 24wt.%, whereas the thickness of the shell is affected by the amount of silica precursor employed. The luminescent activity of the doped nanoparticles was found to be sensitive to the temperature. In fact, the intensity of the emission linearly decreased by increasing the temperature from 20°C to 65°C. The thermoresponsive nanoparticles were functionalized with long aliphatic chains in order to obtain hydrophobic nanoparticles. The developed nanoparticles were immobilized via dip-coating procedure on the surface of hydrophobic porous membranes, such as Polyvinylidene fluoride (PVDF) prepared via Non-Solvent Induced Phase Separation (NIPS), providing local information about the membrane surface temperature.
RESUMEN
Abstract The construction of reservoirs is a common practice in the world. These systems modify the hydric landscape and alter the flow of rivers, becoming lotic environments in lentic. Here we investigated the structure and spatial distribution of rotifers along a tropical reservoir. We sampled four points in the Pedra do Cavalo Reservoir, Bahia, Brazil, bimonthly, between August 2014 and June 2015. We registered more than 70 taxa distributed in 17 families, with the majority of species belonging to the Lecanidae, Brachionidae and Trichocercidae families. The species rarefaction curve did not achieve a total asymptote, indicating that species richness in the reservoir is higher than what was registered. Based in the species frequency of occurrence, we identified 48 rare species, 16 common species, five constant species and one frequent species. The highest beta diversity values were registered in riverine P1 (0.513) and intermediate P2 (0.503), although there were no significant differences between the sampling points. Despite the high abundance values in P1, P2 and P3 no significant differences were found between the studied points. Thus, this study substantially increases the knowledge on the rotifer community in the Paraguaçu River and contributes to future studies that focus on biodiversity, ecology and conservation in the Brazilian reservoir ecosystems.
Resumo A construção de reservatórios é uma prática comum no mundo. Esses sistemas modificam a paisagem hídrica e alteram o fluxo dos rios, tornando-se ambientes lóticos em lênticos. Aqui investigamos a estrutura e distribuição espacial de rotíferos ao longo de um reservatório tropical. Foram amostrados quatro pontos no Reservatório da Pedra do Cavalo, Bahia, Brasil, bimestralmente, entre agosto de 2014 e junho de 2015. Registramos mais de 70 táxons distribuídos em 17 famílias, com a maioria das espécies pertencentes às famílias Lecanidae, Brachionidae e Trichocercidae. A curva de rarefação das espécies não alcançou uma assíntota total, indicando que a riqueza de espécies no reservatório é superior à registrada. Com base na frequência de ocorrência das espécies, identificamos 48 espécies raras, 16 espécies comuns, cinco espécies constantes e uma espécie frequente. Os maiores valores de diversidade beta foram registrados no ribeirinho P1 (0,513) e no intermediário P2 (0,503), embora não houvesse diferenças significativas entre os pontos de amostragem. Apesar dos altos valores de abundância em P1, P2 e P3, não foram encontradas diferenças significativas entre os pontos estudados. Assim, este estudo aumenta substancialmente o conhecimento sobre a comunidade de rotíferos no rio Paraguaçu e contribui para estudos futuros que enfocam biodiversidade, ecologia e conservação nos ecossistemas de reservatórios brasileiros.
RESUMEN
BACKGROUND: Gold-nanobeacons (Au-nanobeacons) have proven to be versatile systems for molecular diagnostics and therapeutic actuators. Here, we present the development and characterization of two gold nanobeacons combined with Förster resonance energy transfer (FRET) based spectral codification for dual mode sequence discrimination. This is the combination of two powerful technologies onto a single nanosystem. RESULTS: We proved this concept to detect the most common fusion sequences associated with the development of chronic myeloid leukemia, e13a2 and e14a2. The detection is based on spectral shift of the donor signal to the acceptor, which allows for corroboration of the hybridization event. The Au-nanobeacon acts as scaffold for detection of the target in a homogenous format whose output capability (i.e. additional layer of information) is potentiated via the spectral codification strategy. CONCLUSIONS: The spectral coded Au-nanobeacons permit the detection of each of the pathogenic fusion sequences, with high specificity towards partial complementary sequences. The proposed BioCode Au-nanobeacon concept provides for a nanoplatform for molecular recognition suitable for cancer diagnostics.
Asunto(s)
Transferencia Resonante de Energía de Fluorescencia/métodos , Proteínas de Fusión bcr-abl/genética , Oro/química , Leucemia Mielógena Crónica BCR-ABL Positiva/genética , Nanopartículas del Metal/química , Técnicas Biosensibles/métodos , Regulación Leucémica de la Expresión Génica , Humanos , Hibridación de Ácido Nucleico/métodosRESUMEN
The impacts of climate and land use changes on streamflow and sediment export were evaluated for a humid (São Lourenço) and a dry (Guadalupe) Mediterranean catchment, using the SWAT model. SWAT was able to produce viable streamflow and sediment export simulations for both catchments, which provided a baseline for investigating climate and land use changes under the A1B and B1 emission scenarios for 2071-2100. Compared to the baseline scenario (1971-2000), climate change scenarios showed a decrease in annual rainfall for both catchments (humid: -12%; dry: -8%), together with strong increases in rainfall during winter. Land use changes were derived from a socio-economic storyline in which traditional agriculture is replaced by more profitable land uses (i.e. corn and commercial forestry at the humid site; sunflower at the dry site). Climate change projections showed a decrease in streamflow for both catchments, whereas sediment export decreased only for the São Lourenço catchment. Land use changes resulted in an increase in streamflow, but the erosive response differed between catchments. The combination of climate and land use change scenarios led to a reduction in streamflow for both catchments, suggesting a domain of the climatic response. As for sediments, contrasting results were observed for the humid (A1B: -29%; B1: -22%) and dry catchment (A1B: +222%; B1: +5%), which is mainly due to differences in the present-day and forecasted vegetation types. The results highlight the importance of climate-induced land-use change impacts, which could be similar to or more severe than the direct impacts of climate change alone.
RESUMEN
Laser Flash Photolysis was employed to measure the deprotonation and reprotonation rate constants of cyanidin 3-monoglucoside (kuromanin) in water/methanol mixtures. It was found that the deprotonation rate constant kd decreases with decreasing water content, reflecting the lack of free water molecules around kuromanin, which may accommodate and stabilize the outgoing protons. On the other hand, the reprotonation rate constant, kp, increases with the decrease in water concentration from a value of kp = 2 × 10(10) l mol(-1) s(-1) in water up to kp = 6 × 10(10) l mol(-1) s(-1) at 5.6M water concentration in the mixture. The higher value of kp at lower water concentrations reflects the fact that the proton is not freely escaping the solvation shell of the molecule. The deprotonation rate constant decreases with decreasing water content, reflecting the lack of free water molecules around kuromanin that can accommodate the outgoing protons. Overall, the acidity constant of the flavylium cation decreases with the decrease in water concentration from pKa values of 3.8 in water to approximately 4.8 in water-depleted media, thus shifting the equilibrium towards the red-coloured form, AH(+), at low water contents. The presence, or lack, of water, will affect the colour shade (red to blue) of kuromanin. This is relevant for its role as an intrinsic food component and as a food pigment additive (E163).
Asunto(s)
Equilibrio Ácido-Base , Antocianinas/química , Glucósidos/química , Agua/análisis , Cationes , Concentración de Iones de Hidrógeno , Metanol/química , Fotólisis , ProtonesRESUMEN
Thirty non-castrated male lambs with 20±2.3 kg average body weight (BW) were randomly assigned to five treatments consisted of different dietary concentrations of crude glycerin (CG; 0, 3, 6, 9 and 12% on DM basis) to evaluate the effects on performance, carcass and meat quality traits. A quadratic effect was observed for performance (P=0.04), final BW (P<0.01) and hot carcass weight (P<0.01). No effects of CG were observed (P>0.05) on carcass pH neither on shear-force, cooking loss and ether extract content in longissimus. The inclusion of CG tended to reduce the Zn content in meat (P=0.09). The data suggests that CG (36.2% of glycerol and 46.5% of crude fat) may be used in diets of finishing lambs with concentrations up to 3% without negative effects on performance and main carcass traits. Moreover, inclusion of CG seems to not affect quality and safety of meat for human consumption.
Asunto(s)
Grasas de la Dieta/administración & dosificación , Glicerol/administración & dosificación , Carne/análisis , Mataderos , Alimentación Animal/análisis , Animales , Culinaria , Dieta/veterinaria , Proteínas en la Dieta/análisis , Masculino , Metales Pesados/análisis , Músculo Esquelético/química , Oveja Doméstica , Zinc/análisisRESUMEN
Previous studies have reported the production of malformed virus-like-particles (VLP) in recombinant host systems. Here we computationally investigate the case of a large triple-layered rotavirus VLP (RLP). In vitro assembly, disassembly and reassembly data provides strong evidence of microscopic reversibility of RLP assembly. Light scattering experimental data also evidences a slow and reversible assembly untypical of kinetic traps, thus further strengthening the fidelity of a thermodynamically controlled assembly. In silico analysis further reveals that under favourable conditions particles distribution is dominated by structural subunits and completely built icosahedra, while other intermediates are present only at residual concentrations. Except for harshly unfavourable conditions, assembly yield is maximised when proteins are provided in the same VLP protein mass composition. The assembly yield decreases abruptly due to thermodynamic equilibrium when the VLP protein mass composition is not obeyed. The latter effect is more pronounced the higher the Gibbs free energy of subunit association is and the more complex the particle is. Overall this study shows that the correct formation of complex multi-layered VLPs is restricted to a narrow range of association energies and protein concentrations, thus the choice of the host system is critical for successful assembly. Likewise, the dynamic control of intracellular protein expression rates becomes very important to minimize wasted proteins.
Asunto(s)
Biología Computacional/métodos , Rotavirus/fisiología , Animales , Cápside/química , Insectos , Cinética , Luz , Modelos Estadísticos , Modelos Teóricos , Dispersión de Radiación , Temperatura , Termodinámica , Proteínas Virales/biosíntesis , Ensamble de VirusRESUMEN
OBJECTIVE: To evaluate and compare the intraobserver and interobserver reliability and agreement for the biparietal diameter (BPD), abdominal circumference (AC), femur length (FL) and estimated fetal weight (EFW) obtained by two-dimensional ultrasound (2D-US) and three-dimensional ultrasound (3D-US). METHODS: Singleton pregnant women between 24 and 40 weeks were invited to participate in this study. They were examined using 2D-US in a blinded manner, twice by one observer, intercalated by a scan by a second observer, to determine BPD, AC and FL. In each of the three examinations, three 3D-US datasets (head, abdomen and thigh) were acquired for measurements of the same parameters. We determined EFW using Hadlock's formula. Systematic errors between 3D-US and 2D-US were examined using the paired t-test. Reliability and agreement were assessed by intraclass correlation coefficients (ICCs), limits of agreement (LoA), SD of differences and proportion of differences below arbitrary points. RESULTS: We evaluated 102 singleton pregnancies. No significant systematic error between 2D-US and 3D-US was observed. The ICC values were higher for 3D-US in both intra- and interobserver evaluations; however, only for FL was there no overlap in the 95% CI. The LoA values were wider for 2D-US, suggesting that random errors were smaller when using 3D-US. Additionally, we observed that the SD values determined from 3D-US differences were smaller than those obtained for 2D-US. Higher proportions of differences were below the arbitrarily defined cut-off points when using 3D-US. CONCLUSION: 3D-US improved the reliability and agreement of fetal measurements and EFW compared with 2D-US.
Asunto(s)
Biometría/métodos , Peso Fetal , Ultrasonografía Prenatal/métodos , Femenino , Edad Gestacional , Humanos , Variaciones Dependientes del Observador , Embarazo , Reproducibilidad de los ResultadosRESUMEN
OBJECTIVE: To evaluate the intra- and interobserver reliability of assessment of three-dimensional power Doppler (3D-PD) indices from single spherical samples of the placenta. METHODS: Women with singleton pregnancies at 24-40 weeks' gestation were included. Three scans were independently performed by two observers; Observer 1 performed the first and third scan, intercalated by the scan of Observer 2. The observers independently analyzed the 3D-PD datasets that they had previously acquired using four different methods, each using a spherical sample: random sample extending from basal to chorionic plate; random sample with 2 cm(3) of volume; directed sample to the region subjectively determined as containing more color Doppler signals extending from basal to chorionic plate; or directed sample with 2 cm(3) of volume. The vascularization index (VI), flow index (FI) and vascularization flow index (VFI) were evaluated in each case. The observers were blinded to their own and each other's results. Additional evaluation was performed according to placental location: anterior, posterior and fundal or lateral. Intra- and interobserver reliability was assessed by intraclass correlation coefficients (ICC). RESULTS: Ninety-five pregnancies were included in the analysis. All three placental 3D-PD indices showed only weak to moderate reliability (ICC < 0.66 and ICC < 0.48, intra- and interobserver, respectively). The highest values of ICC were observed when using directed spherical samples from basal to chorionic plate. When analyzed by placental location, we found lower ICCs for lateral and fundal placentae compared to anterior and posterior ones. CONCLUSION: Intra- and interobserver reliability of assessment of placental 3D-PD indices from single spherical samples in pregnant women greater than 24 weeks' gestation is poor to moderate, and clinical usefulness of these indices is likely to be limited.
Asunto(s)
Imagenología Tridimensional/métodos , Placenta/diagnóstico por imagen , Ultrasonografía Doppler/métodos , Ultrasonografía Prenatal/métodos , Femenino , Humanos , Variaciones Dependientes del Observador , Embarazo , Reproducibilidad de los ResultadosRESUMEN
MicroRNAs are small 21-nucleotide RNA molecules with regulatory roles in development and in response to stress. Expression of some plant miRNAs has been specifically associated with responses to abiotic stresses caused by cold, light, iron, and copper ions. In acid soils, aluminum solubility increases, thereby causing severe damage to plants. Although physiological aspects of aluminum toxicity in plants have been well characterized, the molecular mediators are not fully elucidated. There have been no reports about miRNA responses to aluminum stress. Modulation of miRNA expression may constitute a key element to explain the mechanisms implicated in aluminum toxicity and tolerance. We examined the expression of at least one miRNA member from each miRNA family in rice roots of Oryza sativa spp indica cv. Embrapa Taim and Oryza sativa spp japonica cv. Nipponbare under high concentrations of aluminum. Forty-six miRNA families were effectively detected by quantitative PCR. Among these, 13 were down-regulated and six were up-regulated in roots of the Nipponbare cultivar after 8 h of aluminum treatment. In roots of the Embrapa Taim cultivar, five miRNAs were down-regulated and three were up-regulated. Analyses of their putative targets suggest that these rice miRNAs are involved in the regulation of various metabolic pathways in response to high concentrations of aluminum.
Asunto(s)
Aluminio/farmacología , Regulación de la Expresión Génica/efectos de los fármacos , MicroARNs/biosíntesis , Oryza/metabolismo , Raíces de Plantas/metabolismo , ARN de Planta/biosíntesis , MicroARNs/genética , Oryza/genética , Raíces de Plantas/genética , ARN de Planta/genética , Factores de TiempoRESUMEN
We propose an experimental-based tool for dealing with fluorescence modulation close to nanoparticles for application in studies of fluorophores in the vicinity of gold nanoparticles (AuNPs), typically addressed via theoretical models. We performed a photophysical characterization of fluorophores in the vicinity of AuNPs, showing that correct Φ(F) determination suffers from a local pH effect, and address the observed radiative enhancement. Our approach is based on the experimental assurance that the reference fluorophores are in the same optical conditions as those of the AuNP-fluorophore conjugates. We demonstrate the relevance for introducing corrections for the inner filter effect and the reabsorption of the emitted light caused by AuNPs. The proposed approach could circumvent the need for theoretical based corrections and allow for more accurate determination of fluorescence emission in the vicinity of gold nanoparticles.
RESUMEN
In this study, we examined the physiochemical properties of nasoenteral feeding tubes made from two different types of polymer: silicone materials and polyurethane. The internal surfaces of the nasoenteral feeding tubes were analyzed for their hydrophobicity, roughness, microtopography, rupture-tension and ability to stretch. We also studied the adhesion of an isolated, multi-drug resistant strain of S. aureus to these polymers. The polyurethane nasoenteral tube, which was classified as hydrophilic, was more resistant to rupture-tension and stretching tests than the silicone tube, which was classified as hydrophobic. Additionally, the polyurethane tube had a rougher surface than the silicone tube. Approximately 1.0 log CFU.cm-2 of S. aureus cells adhered to the tubes and this number was not statistically different between the two types of surfaces (p > 0.05). In future studies, new polymers for nasoenteral feeding tubes should be tested for their ability to support bacterial growth. Bacterial adhesion to these polymers can easily be reduced through modification of the polymer's physicochemical surface characteristics.
RESUMEN
IN THIS STUDY, WE EXAMINED THE PHYSIOCHEMICAL PROPERTIES OF NASOENTERAL FEEDING TUBES MADE FROM TWO DIFFERENT TYPES OF POLYMER: silicone materials and polyurethane. The internal surfaces of the nasoenteral feeding tubes were analyzed for their hydrophobicity, roughness, microtopography, rupture-tension and ability to stretch. We also studied the adhesion of an isolated, multi-drug resistant strain of S. aureus to these polymers. The polyurethane nasoenteral tube, which was classified as hydrophilic, was more resistant to rupture-tension and stretching tests than the silicone tube, which was classified as hydrophobic. Additionally, the polyurethane tube had a rougher surface than the silicone tube. Approximately 1.0 log CFU.cm(-2) of S. aureus cells adhered to the tubes and this number was not statistically different between the two types of surfaces (p > 0.05). In future studies, new polymers for nasoenteral feeding tubes should be tested for their ability to support bacterial growth. Bacterial adhesion to these polymers can easily be reduced through modification of the polymer's physicochemical surface characteristics.
Asunto(s)
Humanos , Animales , Angiostrongylus cantonensis , Antinematodos , Meningoencefalitis , Nematodos , Caracoles , Salud Ambiental , Monitoreo EpidemiológicoAsunto(s)
Humanos , Animales , Caracoles , Nematodos , Antinematodos , Angiostrongylus cantonensis , Meningoencefalitis , Monitoreo Epidemiológico , Salud AmbientalRESUMEN
There are numerous reports of coumarin ester derivatives, in particular phosphate esters, as photocleavable cages in biological systems. Despite the comprehensive analysis of the photocleavage mechanism, studies of 4-methylcoumarin caged phosphates and/or nucleotides were always performed at constant pH. In this work, we present the study of the pH effect on the photochemistry of (7-diethylaminocoumarin-4-yl)methyl phosphate (DEACM-P). Fluorescence and photocleavage quantum yields, as well as the fluorescence decay times were measured as a function of the pH. It was found that the pH produces significant changes in the overall photochemical quantum yield of DEACM-P, and the observed changes are complementary to those obtained from the fluorescence quantum yield. Deprotonation of DEACM-HPO(4)(-) to yield DEACM-PO(4)(2-), produces a decrease in the photochemical quantum yield (from 0.0045 to 0.0003) and an increase in the fluorescence quantum yield (from 0.072 to 0.092). Moreover, from the analysis of the decay times, we have also found that hydroxyl ion is not only relevant, but it is mechanistically involved in the photoreaction of DEACM-HPO(4)(-).