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1.
J Chem Inf Model ; 63(24): 7605-7609, 2023 Dec 25.
Artículo en Inglés | MEDLINE | ID: mdl-38084508

RESUMEN

The artificial intelligence (AI) tools based on large-language models may serve as a demonstration that we are reaching a groundbreaking new paradigm in which machines themselves will generate knowledge autonomously. This statement is based on the assumption that the ability to master natural languages is the ultimate frontier for this new paradigm and perhaps an essential step to achieving the so-called general artificial intelligence. Autonomous knowledge generation implies that a machine will be able, for instance, to retrieve and understand the contents of the scientific literature and provide interpretations for existing data, allowing it to propose and address new scientific problems. While one may assume that the continued development of AI tools exploiting large-language models, with more data used for training, may lead these systems to learn autonomously, this learning can be accelerated by devising human-assisted strategies to deal with specific tasks. For example, strategies may be implemented for AI tools to emulate the analysis of multivariate data by human experts or in identifying and explaining patterns in temporal series. In addition to generic AI tools, such as Chat AIs, one may conceive personal AI agents, potentially working together, that are likely to serve end users in the near future. In this perspective paper, we discuss the development of this type of agent, focusing on its architecture and requirements. As a proof-of-concept, we exemplify how such an AI agent could work to assist researchers in materials sciences.


Asunto(s)
Inteligencia Artificial , Ciencia de los Materiales , Humanos , Lenguaje , Aprendizaje , Investigadores
2.
Chaos ; 29(10): 103124, 2019 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-31675835

RESUMEN

Oscillons are time-dependent, localized in space, extremely long-lived states in nonlinear scalar-field models, while kinks are topological solitons in one spatial dimension. In the present work, we show new classes of oscillons and oscillating kinks in a system of two nonlinearly coupled scalar fields in 1+1 spatiotemporal dimensions. The solutions contain a control parameter, the variation of which produces oscillons and kinks with a flat-top shape. The model finds applications in condensed matter, cosmology, and high-energy physics.

3.
Langmuir ; 33(49): 14167-14174, 2017 12 12.
Artículo en Inglés | MEDLINE | ID: mdl-29151353

RESUMEN

The effects induced by antibiotics on the bacterial membrane may be correlated with their bactericidal activity, and such molecular-level interactions can be probed with Langmuir monolayers representing the cell membrane. In this study, we investigated the interaction between [Ru(mcbtz)2(PPh3)2] (RuBTZ, mcbtz = 2-mercaptobenzothiazoline) and [Ru(mctz)2(PPh3)2] (RuCTZ, mctz = 2-mercaptothiazoline) with Langmuir monolayers of a lipid extract of Escherichia coli, an extract of lipopolysaccharides (LPSs), and a zwitterionic phospholipid, dioleoylphosphatidyl choline (DOPC). RuBTZ and RuCTZ had little effects on DOPC, which is consistent with their negligible toxicity toward mammalian cells that may be approximated by a zwitterionic monolayer. Also little were their effects on LPSs. In contrast, RuBTZ and RuCTZ induced expansion in the surface pressure isotherms and decreased the compressional modulus of the E. coli lipid extract. While the more hydrophobic RuBTZ seemed to affect the hydrophobic tails of the E. coli extract monolayer to a larger extent, according to polarization modulation infrared reflection absorption spectroscopy results, evidence of a stronger RuBTZ interaction could not be confirmed unequivocally. Therefore, the interaction with the E. coli cell membrane cannot be directly correlated with the observed higher bactericidal activity of RuBTZ, in comparison to that of RuCTZ. This appears to be a case in which Langmuir monolayer studies do not suffice to determine the mechanisms responsible for the bactericidal activity.

4.
Analyst ; 142(7): 1133-1139, 2017 Mar 27.
Artículo en Inglés | MEDLINE | ID: mdl-28300229

RESUMEN

Herein we present a novel sensor for the detection of monosaccharides (e.g. glucose, fructose) in solution, using electrical impedance spectroscopy. The sensor is based on carbon interdigitated electrodes, printed on paper using screen printing. The surface of the electrodes was modified with a thin layer of hydrogel containing acrylamide copolymerised with 20 mol% 3-(Acrylamido)phenylboronic acid (PBA). It was observed that the hydrogel layers containing 20 mol% PBA swell considerably in the presence of glucose and fructose. This in turn changes the measured impedance across the electrodes, making it a suitable sensor for the quantitative detection of saccharides. We investigated the impedance and capacitance variations with different concentrations of glucose and fructose (0-5 mM) in aqueous phosphate buffer solutions. Variations in impedance were attributed to changes in the dielectric properties of the hydrogel under an applied electric field, due to swelling of the hydrogel layer induced by uptake and binding of sugar molecules to the boronate species within the gel. Impedance measurements at 1 kHz demonstrated that hydrogel swelling leads to an increased mobility of ions within the swollen hydrogel layer. The impedance decreased with increasing sugar concentration and the relative capacitance curves are markedly different for fructose and glucose, as the hydrogel exhibits greater swelling in the presence of fructose than glucose over the same concentration range. As the proposed sensor was shown to be suitable for the detection of glucose at concentration levels found in human sweat, future work will focus on the incorporation of these modified paper-based electrodes into wearable skin patches for non-invasive sugar monitoring in sweat.


Asunto(s)
Espectroscopía Dieléctrica , Hidrogeles , Monosacáridos/análisis , Acrilamidas , Impedancia Eléctrica , Electrodos , Fructosa/análisis , Glucosa/análisis , Humanos , Sudor/química
5.
Pharm Biol ; 52(6): 740-4, 2014 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-24559315

RESUMEN

CONTEXT: Ethnozoological studies have shown that Spilotes pullatus Linn. (Colubridae: Ophidia), is associated with medicinal and magic-religious uses in Brazil. OBJECTIVES: This study was designed to determine the chemical composition of the oil extracted from the body fat of S. pullatus and to test its antimicrobial properties, alone and in association with aminoglycosides, against fungi and bacterial strains in concentrations ranging between 1024 and 0.5 µg/mL. MATERIAL AND METHODS: The snakes were collected in the Chapada do Araripe, county of Crato, Ceará State, Brazil. The oil was extracted in a Soxhlet apparatus using hexane. The methyl esters of the fatty acids present in the samples were identified using GC-MS. The antimicrobial and drug modulatory activities of oil were tested by microdilution against fungal and bacterial strains. RESULTS: The chemical composition of the fixed oils of S. pullatus identified 10 constituents representing 94.97% of the total sample. The percentages of saturated and unsaturated fatty acids were 33.59 and 61.38%, respectively, with the most abundant components being elaidic (37.26%). The oil did not demonstrate any antimicrobial or antifungal activity when tested alone, presenting MIC values ≥ 1024 µg/mL. However, when associated with antibiotics, it demonstrated synergistic effects with gentamicin against all the bacterial lineages assayed, and antagonistic effects with amikacin and neomycin against strains of Escherichia coli. CONCLUSIONS: Oil extracted from the body fat of S. pullatus did not demonstrate any inhibitory effects on bacterial or fungal activities, but was effective in modulating the effects of certain antibiotics.


Asunto(s)
Tejido Adiposo/química , Antiinfecciosos/química , Colubridae , Aceites/química , Animales , Antiinfecciosos/aislamiento & purificación , Antiinfecciosos/farmacología , Aceites/aislamiento & purificación , Aceites/farmacología , Serpientes , Staphylococcus aureus/efectos de los fármacos , Staphylococcus aureus/fisiología
6.
Langmuir ; 29(1): 448-55, 2013 Jan 08.
Artículo en Inglés | MEDLINE | ID: mdl-23215445

RESUMEN

Electrostatic and hydrophobic interactions govern most of the properties of supramolecular systems, which is the reason determining the degree of ionization of macromolecules has become crucial for many applications. In this paper, we show that high-resolution ultraviolet spectroscopy (VUV) can be used to determine the degree of ionization and its effect on the electronic excitation energies of layer-by-layer (LbL) films of poly(allylamine hydrochloride) (PAH) and poly[1-[4-(3-carboxy-4 hydroxyphenylazo)benzene sulfonamido]-1,2-ethanediyl, sodium salt] (PAZO). A full assignment of the VUV peaks of these polyelectrolytes in solution and in cast or LbL films could be made, with their pH dependence allowing us to determine the pK(a) using the Henderson-Hasselbach equation. The pK(a) for PAZO increased from ca. 6 in solution to ca. 7.3 in LbL films owing to the charge transfer from PAH. Significantly, even using solutions at a fixed pH for PAH, the amount adsorbed on the LbL films still varied with the pH of the PAZO solutions due to these molecular-level interactions. Therefore, the procedure based on a comparison of VUV spectra from solutions and films obtained under distinct conditions is useful to determine the degree of dissociation of macromolecules, in addition to permitting interrogation of interface effects in multilayer films.


Asunto(s)
Alilamina/química , Poliestirenos/química , Ionización del Aire , Electrólitos/química , Concentración de Iones de Hidrógeno , Estructura Molecular , Soluciones/química , Propiedades de Superficie , Vacio
7.
Int J Biol Macromol ; 172: 154-161, 2021 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-33428951

RESUMEN

We report on layer-by-layer (LbL) films of chitosans (CHI) and hyaluronic acid (HA) whose properties could be controlled by employing chitosans with different degrees of deacetylation (DD¯ ≈ 85%; 65%; 40%) and high average molecular weight (ca. 106 g/mol). In spite of their high molecular weight, these chitosans are soluble within a wide pH range, including physiological pH. HA/CHI LbL films produced from polymer solutions at pH 4.5 were thinner, smoother, more hydrophilic than those prepared at pH 7.2. This is attributed to the more extended conformation adopted by chitosan due to its very high charge density at low pH, favoring a compact chain packing during the film formation and resulting in lower film thickness and roughness. The smoother HA/CHI LbL films obtained at pH 4.5 were effective against Escherichia coli, while the thicker, rougher LbL films fabricated at pH 7.2 could be used in the controlled released of Rose Bengal dye. In summary, the tuning of only two parameters, i.e. solution pH and DD¯ of chitosans, provides access to a library of HA/CHI LbL films for tailored, diversified applications.


Asunto(s)
Antiinfecciosos/química , Quitosano/química , Antiinfecciosos/farmacología , Escherichia coli/efectos de los fármacos , Ácido Hialurónico/química , Concentración de Iones de Hidrógeno , Interacciones Hidrofóbicas e Hidrofílicas , Polímeros/química
8.
Chem Phys Lipids ; 230: 104930, 2020 08.
Artículo en Inglés | MEDLINE | ID: mdl-32470442

RESUMEN

Understanding protein aggregation is essential to unveil molecular mechanisms associated with neurodegenerative diseases such as Alzheimer's, Huntington's and spongiform encephalopathy, particularly to determine the role of interaction with cell membranes. In this study, we employ Langmuir monolayers as cell membrane models to mimic interaction with the peptide KTNMHKHMAGAAAAGAVVGGLG-OH, a fragment from the human prion protein including residues 106-127, believed to be involved in protein aggregation. Using in situ polarization-modulated infrared reflection adsorption spectroscopy (PM-IRRAS) for Langmuir monolayers and FTIR for solid films, we found that PrP106-127 adopts mainly ß-sheets, random coils and ß-turns in Langmuir monolayers and in Langmuir-Blodgett (LB) and cast films. This also applies to monolayers and solid films made with PrP106-127 and a brain total lipid extract (BTLE). In contrast, some α-helices are observed in the secondary structure of PrP106-127 in monolayers, and especially in solid films, of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC). In summary, in a model representing brain cells (BTLE), the secondary structure of PrP106-127 is typical of fiber aggregates, while aggregation is unlikely if PrP106-127 interacts with a membrane model (DOPC) characteristic of mammalian cells.


Asunto(s)
Encéfalo/metabolismo , Lípidos/química , Fragmentos de Péptidos/química , Proteínas Priónicas/química , Secuencia de Aminoácidos , Membrana Celular/química , Conformación Proteica en Lámina beta
9.
Plant Biol (Stuttg) ; 21(4): 662-669, 2019 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-30676681

RESUMEN

Several studies on cytogenetic characterisation of passion flowers are helpful to elucidate doubts about taxa relationships, delimitation and classification into more coherent groups based on karyomorphological data. Molecular and conventional cytogenetic techniques were applied to three Passiflora species with red flowers, P. coccinea, P. vitifolia and P. tholozanii, for species karyotype relationships. Additionally, for descriptive morphology, were used flowers, leaves and seeds. Results describe for the first time the karyomorphological and chromosome number (2n = 18) for P. tholozanii. anova was performed (P < 0.05) and statistical significance for average chromosome size (CV: 16.53%) between species. Genomic in situ hybridisation (GISH) proved relationships between P. coccinea and P. tholozanii, which suggests a common origin, however, we could not identify hybridisation between genomic probes from P. vitifolia in P. tholozanii chromosomes. Among the species analysed, P. tholozanii has great similarity in karyotypic and morphology to P. coccinea but not to P. vitifolia. We suggest the inclusion of P. tholozanii in the same subgenus and section as P. coccinea based on the similarity in karyomorphological and morphological traits between the species. Additionally, GISH might indicate a common or hybrid origin of P. tholozanii.


Asunto(s)
Passiflora/citología , Colorantes Azulados , Cromosomas de las Plantas/genética , Análisis Citogenético , Cariotipificación , Passiflora/anatomía & histología , Passiflora/genética , Cápsula de Raíz de Planta/anatomía & histología , Cápsula de Raíz de Planta/citología , Cápsula de Raíz de Planta/genética
10.
Pulmonology ; 25(1): 32-39, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-30077629

RESUMEN

INTRODUCTION: Immigrants may utilize health care services differently than other residents and may also have a greater risk for tuberculosis (TB). OBJECTIVE: Identify barriers to healthcare access by immigrants, factors associated with these barriers, and discuss strategies that may reduce these barriers. MATERIAL AND METHODS: Anonymous questionnaires were given to immigrants at National Immigrant Support Centres between 2015 and 2016. Barriers to healthcare were identified using logistic regression. RESULTS: One-hundred and nineteen questionnaires were administered to immigrants, 9 of whom (8%) presented with TB while in Portugal. Twenty-one percent of immigrants reported barriers to healthcare access, and 69% had general practitioners (GPs). The presence of barriers to healthcare access was negatively associated with having a GP and with being married or in a de facto union. CONCLUSIONS: A considerable proportion of immigrants reported having difficulties accessing healthcare services in Portugal where legally these barriers are nonexistent. Certain factors were associated with these difficulties.


Asunto(s)
Emigrantes e Inmigrantes/estadística & datos numéricos , Accesibilidad a los Servicios de Salud/estadística & datos numéricos , Tuberculosis/epidemiología , Adulto , Barreras de Comunicación , Estudios Transversales , Femenino , Médicos Generales/provisión & distribución , Humanos , Masculino , Persona de Mediana Edad , Portugal/epidemiología , Medición de Riesgo/métodos , Encuestas y Cuestionarios
11.
J Phys Chem B ; 112(48): 15275-82, 2008 Dec 04.
Artículo en Inglés | MEDLINE | ID: mdl-18989908

RESUMEN

The possibility of generating distinct film properties from the same material is crucial for a number of applications, which can only be achieved by controlling the molecular architecture. In this paper we demonstrate as a proof-of-principle that ultrathin films produced from iron phthalocyanine (FePc) may be used to detect trace amounts of copper ions in water, where advantage was taken of the cross sensitivity of the sensing units that displayed distinct electrical properties. The ultrathin films were fabricated with three methods, namely physical vapor deposition (PVD), Langmuir-Blodgett (LB), and electrostatic layer-by-layer (LbL) techniques, where for the latter tetrasulfonated phthalocyanine was used (FeTsPc). PVD and LB films were more homogeneous than the LbL films at both microscopic and nanoscopic scales, according to results from micro-Raman spectroscopy and atomic force microscopy (AFM), respectively. From FTIR spectroscopy data, these more homogeneous films were found to have FePc molecules oriented preferentially, tilted in relation to the substrate surface, while FeTsPc molecules were isotropically distributed in the LbL films. Impedance spectroscopy measurements with films adsorbed onto interdigitated gold electrodes indicated that the electrical response depends on the type of film-forming method and varies with incorporation of copper ions in aqueous solutions. Using principal component analysis (PCA), we were able to exploit the cross sensitivity of the sensing units and detect copper ions (Cu(2+)) down to 0.2 mg/L, not only in ultrapure water but also in distilled and tap water. This level of sensitivity is sufficient for quality control of water for human consumption, with a fast, low-cost method.

12.
Micron ; 39(8): 1119-25, 2008 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-18706822

RESUMEN

The study of intermolecular interactions at interfaces is essential for a number of applications, in addition to the understanding of mechanisms involved in sensing and biosensing with liquid samples. There are, however, only a few methods to probe such interfacial phenomena, one of which is the atomic force spectroscopy (AFS) where the force between an atomic force microscope tip and the sample surface is measured. In this study, we used AFS to estimate adhesion forces for a nanostructured film of poly(o-ethoxyaniline) (POEA) doped with various acids, in measurements performed in air. The adhesion force was lower for POEA doped with inorganic acids, such as HCl and H(2)SO(4), than with organic acids, because the counterions were screened by the ethoxy groups. Significantly, the morphology of POEA both in the film and in solution depends on the doping acid. Using small-angle X-ray scattering (SAXS) we observed that POEA dissolved in a mixture of dimethyl acetamide exhibits a more extended coil-like conformation, with smaller radius of gyration, than for POEA in water, as in the latter POEA solubility is lower. In AFS measurements in a liquid cell, the force curves for a POEA layer displayed an attractive region for pH>or=5 due to van der Waals interactions, with no contribution from a double-layer since POEA was dedoped. In contrast, for pH

13.
Pulmonology ; 2018 Jan 03.
Artículo en Inglés | MEDLINE | ID: mdl-29306673

RESUMEN

INTRODUCTION: Early diagnosis is necessary for the success of the tuberculosis (TB) program. GOAL: To identify factors associated with diagnosis delay of TB in Huambo, Angola. MATERIAL AND METHODS: Cross-sectional study carried out in patients diagnosed with TB at the Huambo Anti-Tuberculosis Dispensary (ATD) in the period between October 2015 and January 2016. RESULTS: The 247 patients included in the analysis had a median age of 27 years and a median diagnosis delay of 64 days. In the univariate analysis, age, consumption of alcoholic beverages, living in a residence further than 10km from a healthcare unit, and looking for any other health unit than the emergency unit were associated with longer diagnosis delay. In the multivariate analysis model, to be between 30 and 44 years of age (p=0.018), to live in a residence more than 10km from a healthcare unit (p=0.006) and to turn to traditional medicine as the first healthcare option (p<0.001) were factors that led to greater time delay before diagnosis. CONCLUSIONS: In the Huambo province, age, distance to healthcare facility and the first healthcare service consulted were associated with diagnosis delay of TB.

14.
J Colloid Interface Sci ; 515: 101-108, 2018 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-29331776

RESUMEN

A green approach for the preparation of carbon black (CB) and electrochemically reduced graphene oxide composite (ERGO) is described based on screen printed carbon electrodes (SPCEs) fabricated on poly(ethylene terephthalate) (PET) as electrochemical sensors. This approach leads to a heterogeneous hydrophilic surface with high concentration of defect sites according to scanning electron microscopy, contact angle and Raman spectroscopy measurements. The SPCE/CB-ERGO sensor was tested with dopamine (DA), epinephrine (EP) and paracetamol (PCM), exhibiting an enhanced electrocatalytic performance compared to the bare SPCE. It displayed a wider linear range, lower limit of detection and a remarkably higher analytical sensitivity, viz. 1.5, 0.13 and 0.028 A L mol-1 for DA, EP and PCM, respectively, being also capable of simultaneous determination of the three analytes. Such high performance is demonstration that SPCE/CB-ERGO may serve as generic platform for cost-effective flexible electrochemical sensors.

15.
Oper Dent ; 43(3): 250-260, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29533717

RESUMEN

OBJECTIVE: This randomized clinical trial evaluated the effect of 35% hydrogen peroxide in comparison with 37% carbamide peroxide in a nonvital bleaching technique of "walking bleaching" (four sessions of treatment) on periodontal markers: nuclear factor kappa B-ligand (RANK-L-process of root resorption marker) and interleukin 1ß (IL-1ß-inflammatory response marker). METHODS AND MATERIALS: Fifty volunteers presenting with discoloration of nonvital teeth and endodontic treatment in good condition participated. Fifty teeth were randomly divided into two study groups according to bleaching gel: HP = 35% hydrogen peroxide (n=25) and 37% carbamide peroxide (n=25). Nonvital bleaching was performed with a walking bleaching technique consisting of four sessions of bleach application. Gingival crevicular fluid samples were taken in order to quantify the RANK-L and IL-1ß levels by enzyme-linked immunosorbent assay. Samples were obtained from six periodontal sites for each bleached tooth: three vestibular and three palatine (mesial, middle, and distal) at seven time periods: baseline, after each of the four sessions of nonvital bleaching, at one week, and at one month after nonvital bleaching. Tooth color variations were analyzed in each session by VITA Bleachedguide 3D-MASTER (ΔSGU). RESULTS: Significant increments in the RANK-L and IL-1ß levels were detected in each evaluated time compared with baseline ( p<0.05); however, no differences were detected between hydrogen peroxide and carbamide peroxide on increments of the biomarkers studied. The change of color was effective for both nonvital bleaching therapies ( p<0.05). CONCLUSIONS: Nonvital bleaching induced a significant increment in the RANK-L and IL-1ß levels in periodontal tissues around bleached, nonvital teeth.


Asunto(s)
Resorción Ósea/inducido químicamente , Blanqueamiento de Dientes/efectos adversos , Adulto , Anciano , Biomarcadores/análisis , Peróxido de Carbamida , Ensayo de Inmunoadsorción Enzimática , Femenino , Líquido del Surco Gingival/química , Humanos , Peróxido de Hidrógeno/efectos adversos , Peróxido de Hidrógeno/uso terapéutico , Interleucina-1beta/análisis , Masculino , Persona de Mediana Edad , Peróxidos/efectos adversos , Peróxidos/uso terapéutico , Ligando RANK/análisis , Blanqueamiento de Dientes/métodos , Blanqueadores Dentales/efectos adversos , Blanqueadores Dentales/uso terapéutico , Urea/efectos adversos , Urea/análogos & derivados , Urea/uso terapéutico , Adulto Joven
16.
Community Dent Health ; 24(1): 31-6, 2007 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-17405468

RESUMEN

OBJECTIVE: To evaluate the cumulative incidence of enamel defects (ED) and its correlation with life course events such as malnutrition and pre- and postnatal infections, in a cohort of children of low socioeconomic status. METHODS: The children were registered at birth and examined from 12 to 36 months of age. At the baseline, 246 were examined and in the follow-up, 228. The teeth were examined under natural light and dried with gauze. ED was determined by the DDE index. RESULTS: Results show that gender was not significant. The cumulative incidence of ED at the last recall examination was 78.9%. The most prevalent type of defect was diffuse opacity, present on the gingival half of the buccal surface (p < 0.001). For logistic regression analysis maternal infections, intrauterine growth retardation (IUGR), malnutrition and postnatal infections were selected as predictor variables for the occurrence of enamel defects. CONCLUSIONS: The results indicate that life course events such as undernutrition and childhood infections during teeth development may be associated with enamel defects in socioeconomically underprivileged communities and may compromise the oral health-related quality of life.


Asunto(s)
Esmalte Dental/anomalías , Diente Primario/anomalías , Infecciones Bacterianas/complicaciones , Brasil , Preescolar , Estudios de Cohortes , Hipoplasia del Esmalte Dental/etiología , Femenino , Retardo del Crecimiento Fetal/fisiopatología , Estudios de Seguimiento , Trastornos del Crecimiento/complicaciones , Humanos , Lactante , Recién Nacido , Recién Nacido Pequeño para la Edad Gestacional , Estudios Longitudinales , Masculino , Desnutrición/complicaciones , Estado Nutricional , Odontogénesis/fisiología , Pobreza , Embarazo , Complicaciones Infecciosas del Embarazo/fisiopatología , Clase Social , Poblaciones Vulnerables
18.
Oper Dent ; 42(1): 41-52, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-27571237

RESUMEN

OBJECTIVE: The aim was to evaluate the color longevity after nine months of in-office bleaching with gel (6% hydrogen peroxide), to compare this to a control concentration of 35% in a split-mouth study model, and to assess the dental confidence and psychosocial impact on patients. METHODS AND MATERIALS: Twenty-seven patients were assessed at the nine-month recall. The bleaching procedure with 6% or 35% hydrogen peroxide gel was performed randomly in the upper hemi-arch of each patient. The color was measured at baseline and at one week, one month, and nine months after the procedure, using the Vita Easyshade spectrophotometer, the Vita classical shade guide organized by value, and Vita Bleach Guide 3DMaster. Moreover, two surveys, OHIP-Esthetics and PIDAQ, were used to assess the esthetic self-perception and psychosocial impact of the bleaching procedure. During the nine-month recall, the color was assessed before and after dental prophylaxis. RESULTS: Twenty-seven patients participated in the nine-month recall. There was a significant difference in ΔE between the two groups at all times assessed (p<0.011). The ΔL, Δa, and Δb showed a difference between the two groups at all times assessed (p<0.038), except for ΔL from the baseline vs nine-month after prophylaxis value (p>0.20). There was no significant difference in ΔSGU at all times (p>0.05). There was a significant difference in OHIP-Esthetics and PIDAQ sums compared with baseline scores (p<0.03). CONCLUSION: The two compounds remained effective at nine months, with a slight rebound of color, and maintained their objective color difference but not the subjective color difference. Patients were satisfied with the bleaching procedure, and this had a positive impact on esthetic perception and a positive psychosocial impact at the nine-month recall.


Asunto(s)
Estética Dental , Peróxido de Hidrógeno/uso terapéutico , Blanqueadores Dentales/uso terapéutico , Blanqueamiento de Dientes/métodos , Blanqueamiento de Dientes/psicología , Adulto , Consultorios Odontológicos , Femenino , Humanos , Peróxido de Hidrógeno/administración & dosificación , Masculino , Blanqueadores Dentales/administración & dosificación , Resultado del Tratamiento
19.
Oper Dent ; 42(3): 244-252, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28467262

RESUMEN

OBJECTIVE: The aim of this blinded and randomized clinical trial was to compare two application protocols (one 36-minute application vs three 12-minute applications). We then assessed the effectiveness of the bleaching and any increase in sensitivity that was induced by bleaching via a split-mouth design. METHODS AND MATERIALS: Thirty patients were treated. One group had a half arch of teeth treated with a traditional application protocol (group A: 3 × 12 minutes for two sessions). The other received an abbreviated protocol (group B: 1 × 36 minutes over two sessions). Two sessions were appointed with a two-day interval between them. The tooth color was registered at each session, as well as one week and one month after completing the treatment via a spectrophotometer. This measured L*, a*, and b*. This was also evaluated subjectively using the VITA classical A1-D4 guide and VITA Bleachedguide 3D-MASTER. Tooth sensitivity was registered according to the visual analogue scale (VAS) scale. Tooth color variation and sensitivity were compared between groups. RESULTS: Both treatments changed tooth color vs baseline. The ΔE* = 5.71 ± 2.62 in group A, and ΔE* = 4.93 ± 2.09 in group B one month after completing the bleaching (p=0.20). No statistical differences were seen via subjective evaluations. There were no differences in tooth sensitivity between the groups. The absolute risk of sensitivity reported for both groups was 6.25% (p=0.298). The intensity by VAS was mild (p=1.00). CONCLUSIONS: We used hydrogen peroxide (6%) that was light activated with a hybrid LED/laser and two different protocols (one 36-minute application vs three 12-minute applications each for two sessions). These approaches were equally effective. There were no differences in absolute risk of sensitivity; both groups reported mild sensitivity.


Asunto(s)
Peróxido de Hidrógeno/uso terapéutico , Blanqueadores Dentales/uso terapéutico , Blanqueamiento de Dientes/métodos , Decoloración de Dientes/tratamiento farmacológico , Adulto , Sensibilidad de la Dentina/inducido químicamente , Femenino , Geles , Humanos , Masculino , Resultado del Tratamiento
20.
Int J Tuberc Lung Dis ; 21(3): 327-332, 2017 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-28225344

RESUMEN

BACKGROUND: Tuberculosis (TB) is a major concern among high-risk populations such as the homeless. OBJECTIVES: To evaluate TB incidence and treatment outcomes among homeless patients in Portugal and to identify predictors of unsuccessful TB treatment outcomes among the homeless. DESIGN: This was a retrospective cohort study of all TB patients notified in Portugal from 2008 to 2014. Characteristics of homeless TB patients were assessed and predictors of unsuccessful TB treatment were determined using logistic regression. RESULTS: TB incidence among the homeless was 122/100,000 homeless persons and was positively correlated with TB incidence among non-homeless persons. Homeless TB patients had a higher prevalence of alcohol and/or drug use, human immunodeficiency virus (HIV) co-infection, cavitary TB and smear positivity. The rate of unsuccessful treatment outcomes among the homeless was 28.6%, and was significantly associated with increased age, injection drug use (IDU) and HIV co-infection. CONCLUSION: TB incidence among homeless persons was five times that among the non-homeless, and higher in regions with greater TB incidence among non-homeless persons. The successful treatment outcome rate was lower. Predictors of unsuccessful treatment were age, IDU and HIV co-infection. Integrated TB programmes targeting homeless and non-homeless patients, with measures targeting specific characteristics, may contribute to TB elimination in Portugal.


Asunto(s)
Antituberculosos/administración & dosificación , Infecciones por VIH/epidemiología , Personas con Mala Vivienda/estadística & datos numéricos , Tuberculosis/epidemiología , Adulto , Anciano , Consumo de Bebidas Alcohólicas/epidemiología , Estudios de Cohortes , Coinfección , Femenino , Humanos , Incidencia , Modelos Logísticos , Masculino , Persona de Mediana Edad , Portugal/epidemiología , Prevalencia , Estudios Retrospectivos , Factores de Riesgo , Trastornos Relacionados con Sustancias/epidemiología , Resultado del Tratamiento , Tuberculosis/tratamiento farmacológico
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