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1.
Rev. cient. cienc. salud ; 6: 1-12, 30-01-2024.
Artículo en Inglés | LILACS, BDNPAR | ID: biblio-1565435

RESUMEN

Introducción. Los niños requieren especial dedicación para lograr espirometrías de calidad. Objetivo. Este trabajo evalúa la frecuencia de maniobras aceptables en escolares, la utilidad de gestos de incentivo para optimizar la obtención de pruebas de alta calidad y realiza un análisis de ajuste a varias ecuaciones de referencia. Materiales y Métodos. Se realizaron maniobras espiratorias forzadas en un grupo de escolares de Asunción- Paraguay, escogiendo variables recomendadas para la interpretación en un espirómetro portátil, para evaluar la frecuencia de pruebas de calidad. Aquellos que no consiguieron estudios aceptables, fueron sometidos a un entrenamiento con silbato en rollo (juguete) para evaluar el desempeño ulterior. Los resultados de alta calidad fueron pareados a valores esperados determinados por diversas ecuaciones buscando evaluar el grado de adecuación. Resultados. De 113 escolares, el 58,4% pudo conseguir maniobras de grado A o B. Después del estímulo con el silbato en rollo, la frecuencia de estudios aceptables ascendió a 79,6%. Los parámetros de referencia con mejor ajuste fueron aquellos determinados por la Global Lung Initiative (GLI). Conclusión. Los incentivos lúdicos son una alternativa para optimizar la obtención de pruebas de espirometría en escolares, que con el uso de parámetros de GLI adecuarían el manejo clínico de ciertas enfermedades respiratorias.


Introduction. Children require special dedication to achieve high quality spirometry. Objective. This work evaluates the frequency of acceptable maneuvers in schoolchildren, the usefulness of incentive gestures to optimize the obtaining of high-quality tests, and performs an analysis of adjustments to several reference equations. Material and Methods. Forced expiratory maneuvers were performed in a group of schoolchildren from Asunción, Paraguay, choosing variables recommended for interpretation in a portable spirometer, to evaluate the frequency of high quality tests. Those who did not achieve acceptable studies were subjected to training with a roll whistle (toy) to evaluate their subsequent performance. The high-quality results were matched to expected values determined by various equations to evaluate adequacy. Results. Of 113 schoolchildren, 58,4% were able to achieve grade A or B maneuvers. After the stimulus with the roll whistle, the frequency of acceptable studies rose to 79,6%. The reference parameters with the best fit were those determined by the Global Lung Initiative (GLI). Conclusion. Playful incentives are an alternative to obtaining acceptable spirometry tests in schoolchildren, which, with the use of GLI parameters, would adjust the clinical management of certain respiratory diseases.


Asunto(s)
Humanos , Masculino , Femenino , Niño , Pruebas de Función Respiratoria , Espirometría , Niño , Capacidad Vital , Volumen Espiratorio Forzado
2.
An. Fac. Med. (Perú) ; 84(3)sept. 2023.
Artículo en Español | LILACS-Express | LILACS | ID: biblio-1520001

RESUMEN

La lesión del manguito rotador es una causa importante de dolor y disfunción del hombro. El tratamiento de las roturas masivas e irreparables del manguito rotador sigue siendo un gran reto para los ortopedistas por su complejidad y severidad. Una de las alternativas prometedoras para su manejo es el uso del balón subacromial. Presentamos el caso de una mujer de 67 años con diagnóstico de rotura masiva e irreparable del manguito rotador en el hombro derecho (grado III de Patte, grado IV Goutallier y grado II de Hamada) sin artrosis glenohumeral, tenosinovitis del bíceps y subescapular íntegro. La escala de constant preoperatorio fue de 40 puntos. Se realizó una reparación parcial artroscópica del tendón supraespinoso e infraespinoso asociado a una tenodesis suprapectoral del bíceps y la colocación del balón subacromial. La paciente realizó rehabilitación con mejoría de los arcos de movilidad, disminución del dolor e incremento de la fuerza del hombro derecho. La escala de constant postoperatorio fue de 80 puntos a la semana doce. El balón subacromial es una buena alternativa de tratamiento para las lesiones irreparables del manguito rotador con resultados óptimos a corto plazo en cuanto a dolor y función.


The rotator cuff injury is a significant cause of shoulder pain and dysfunction. Treating massive and irreparable rotator cuff tears remains a major challenge for orthopedists due to their complexity and severity. One promising alternative for managing these cases is the use of subacromial balloons. In this study, we present the case of a 67-year-old woman diagnosed with a massive and irreparable rotator cuff tear in her right shoulder (Grade III Patte, Grade IV Goutallier, and Grade II Hamada), without glenohumeral arthritis, intact biceps tenosynovitis, and subscapularis. The preoperative Constant score was 40 points. The patient underwent partial arthroscopic repair of the supraspinatus and infraspinatus tendons, along with a suprapectoral biceps tenodesis and subacromial balloon placement. Postoperative rehabilitation led to improved range of motion, reduced pain, and increased strength in the right shoulder. The postoperative Constant score reached 80 points at the twelve-week mark. The subacromial balloon proves to be a promising treatment alternative for irreparable rotator cuff injuries, providing optimal short-term results in terms of pain relief and functionality.

3.
J Chem Inf Model ; 61(7): 3213-3231, 2021 07 26.
Artículo en Inglés | MEDLINE | ID: mdl-34191520

RESUMEN

In silico prediction of antileishmanial activity using quantitative structure-activity relationship (QSAR) models has been developed on limited and small datasets. Nowadays, the availability of large and diverse high-throughput screening data provides an opportunity to the scientific community to model this activity from the chemical structure. In this study, we present the first KNIME automated workflow to modeling a large, diverse, and highly imbalanced dataset of compounds with antileishmanial activity. Because the data is strongly biased toward inactive compounds, a novel strategy was implemented based on the selection of different balanced training sets and a further consensus model using single decision trees as the base model and three criteria for output combinations. The decision tree consensus was adopted after comparing its classification performance to consensuses built upon Gaussian-Naïve-Bayes, Support-Vector-Machine, Random-Forest, Gradient-Boost, and Multi-Layer-Perceptron base models. All these consensuses were rigorously validated using internal and external test validation sets and were compared against each other using Friedman and Bonferroni-Dunn statistics. For the retained decision tree-based consensus model, which covers 100% of the chemical space of the dataset and with the lowest consensus level, the overall accuracy statistics for test and external sets were between 71 and 74% and 71 and 76%, respectively, while for a reduced chemical space (21%) and with an incremental consensus level, the accuracy statistics were substantially improved with values for the test and external sets between 86 and 92% and 88 and 92%, respectively. These results highlight the relevance of the consensus model to prioritize a relatively small set of active compounds with high prediction sensitivity using the Incremental Consensus at high level values or to predict as many compounds as possible, lowering the level of Incremental Consensus. Finally, the workflow developed eliminates human bias, improves the procedure reproducibility, and allows other researchers to reproduce our design and use it in their own QSAR problems.


Asunto(s)
Leishmania , Relación Estructura-Actividad Cuantitativa , Teorema de Bayes , Ensayos Analíticos de Alto Rendimiento , Humanos , Reproducibilidad de los Resultados
4.
J Oncol ; 2020: 2679046, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33312200

RESUMEN

Hematologic malignancies such as leukemias and lymphomas are among the leading causes of pediatric cancer death worldwide, and although survival rates have improved with conventional treatments, the development of drug-resistant cancer cells may lead to patient relapse and limited possibilities of a cure. Drug-resistant cancer cells in these hematologic neoplasms are induced by overexpression of the antiapoptotic B-cell lymphoma 2 (Bcl-2) protein families, such as Bcl-XL, Bcl-2, and Mcl-1. We have previously shown that peptides from the BH3 domain of the proapoptotic Bax protein that also belongs to the Bcl-2 family may antagonize the antiapoptotic activity of the Bcl-2 family proteins, restore apoptosis, and induce chemosensitization of tumor cells. Furthermore, cell-permeable Bax BH3 peptides also elicit antitumor activity and extend survival in a murine xenograft model of human B non-Hodgkin's lymphoma. However, the activity of the BH3 peptides of the proapoptotic Bak protein of the Bcl-2 family against these hematologic malignant cells requires further characterization. In this study, we report the ability of the cell-permeable Bak BH3 peptide to restore apoptosis and induce chemosensitization of acute lymphoblastic leukemia and non-Hodgkin's lymphoma cell lines, and this event is enhanced with the coadministration of cell-permeable Bax BH3 peptide and represents an attractive approach to improve the patient outcomes with relapsed or refractory hematological malignant cells.

5.
Sensors (Basel) ; 20(18)2020 Sep 14.
Artículo en Inglés | MEDLINE | ID: mdl-32937798

RESUMEN

This paper presents a system of sensors used in flash flood prediction that offers critical real-time information used to provide early warnings that can provide the minutes needed for persons to evacuate before imminent events. Flooding is one of the most serious natural disasters humans confront in terms of loss of life and results in long-term effects, which often have severely adverse social consequences. However, flash floods are potentially more dangerous to life because there is often little or no forewarning of the impending disaster. The Emergency Water Information Network (EWIN) offers a solution that integrates an early warning system, notifications, and real-time monitoring of flash flood risks. The platform has been implemented in Colima, Mexico covering the Colima and Villa de Alvarez metropolitan area. This platform consists of eight fixed riverside hydrological monitoring stations, eight meteorological stations, nomadic mobile monitoring stations called "drifters" used in the flow, and a sniffer with data muling capability. The results show that this platform effectively compiles and forwards information to decision-makers, government officials, and the general public, potentially providing valuable minutes for people to evacuate dangerous areas.

6.
Beilstein J Nanotechnol ; 10: 2238-2250, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31807409

RESUMEN

Herein, we report the synthesis of nontoxic pyrite iron sulfide (FeS2) nanocrystals (NCs) using a two-pot method. Moreover, we study the influence of these NCs incorporated into the PTB7:PC71BM active layer of bulk-heterojunction ternary organic photovoltaic (OPV) cells. The OPV devices are fabricated with the direct configuration glass/ITO/PEDOT:PSS/PTB7:PC71BM:FeS2/PFN/FM. The Field's metal (FM) is a eutectic alloy composed of 32.5% Bi, 51% In and 16.5% Sn by weight that melts at 62 °C. It is deposited on the active layer/PFN under atmospheric conditions. Ternary active layers are prepared by adding small amounts of the semiconducting FeS2 NCs at different weight ratios of 0.0, 0.25, 0.5, and 1.0 wt % with respect to the electron donor PTB7. With respect to the reference device (without FeS2), a 21% increase in the power conversion efficiency (PCE) is observed for OPVs with 0.5 wt % FeS2, such that the PCE of the OPVs is enhanced from 5.69 to 6.47%. According to the Kruskal-Wallis and Mann-Whitney statistical tests, all OPV devices follow the same trend.

7.
Data Brief ; 21: 1618-1621, 2018 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-30480075

RESUMEN

This article presents the data of a PV system using fuzzy logic and the perturb and observe (P&O) algorithm, under sudden changes in the solar irradiance and the operating temperature of a PV module. The mathematical modeling of the PV module, the dc-dc converter and the fuzzy and P&O controllers were discussed in our previous work entitled "Fuzzy logic based MPPT controller for a PV System" (Algarín et al., 2017) [1]. Data are presented for six cases with different operating conditions: in the first case the two controllers were evaluated for standard test conditions with constant solar irradiance of 1000 W/m2 and constant temperature of 25 °C. In the remaining five cases sudden increases and decreases were made in the operating conditions of the PV module. Finally, the theoretical data of the PV system are presented, which can be used as a reference to analyze the data obtained with the two controllers in the six cases. Data are provided in Supplementary material in Tables 1-7.

8.
Eur J Oral Sci ; 126(3): 234-243, 2018 06.
Artículo en Inglés | MEDLINE | ID: mdl-29442393

RESUMEN

The purpose of this study was to characterize mineral trioxide aggregates (MTA) enriched with iron disulfide (FeS2 ) nanostructures at different concentrations, and to investigate their storage modulus, radiopacity, setting time, pH, cytotoxicity, and antimicrobial activity. Iron disulfide nanostructures [with particle size of 0.357 ± 0.156 µm (mean ± SD)] at weight ratios of 0.2, 0.4, 0.6, 0.8, and 1.0 wt% were added to white MTA (wMTA). The radiopacity, rheological properties, setting time, and pH, as well as the cytotoxicity (assessed using the MTT assay) and antibacterial activity (assessed using the broth microdilution test) were determined for MTA/FeS2 nanostructures. The nanostructures did not modify the radiopacity values of wMTA (~6 mm of aluminium); however, they reduced the setting time from 18.2 ± 3.20 min to 13.7 ± 1.8 min, and the storage modulus was indicative of a good stiffness. Whereas the wMTA/FeS2 nanostructures did not induce cytotoxicity when in contact with human pulp cells (HPCs) and human gingival fibroblasts (HGFs), they showed bacteriostatic activity against Staphylococcus aureus, Escherichia coli, and Enterococcus faecalis. Adding FeS2 nanostructures to MTA might be an option for improving the root canal sealing and antibacterial effects of wMTA in endodontic treatments.


Asunto(s)
Compuestos de Aluminio/farmacología , Compuestos de Calcio/farmacología , Citotoxinas/farmacología , Pulpa Dental/efectos de los fármacos , Hierro/farmacología , Nanoestructuras , Óxidos/farmacología , Silicatos/farmacología , Sulfuros/farmacología , Compuestos de Aluminio/química , Bacterias/efectos de los fármacos , Compuestos de Calcio/química , Citotoxinas/química , Materiales Dentales/farmacología , Pulpa Dental/citología , Combinación de Medicamentos , Fibroblastos/efectos de los fármacos , Encía , Humanos , Concentración de Iones de Hidrógeno , Hierro/química , Microscopía Electroquímica de Rastreo , Óxidos/química , Silicatos/química , Sulfuros/química
9.
Rev. colomb. gastroenterol ; 32(4): 358-368, 2017. tab, graf
Artículo en Español | LILACS | ID: biblio-900714

RESUMEN

Resumen Introducción: la deficiencia de lipasa ácida lisosomal (LAL-D) es una entidad de herencia autosómica recesiva que lleva a la acumulación de esteres de colesterol y triglicéridos en el hígado, bazo y otros órganos. La edad de inicio y la tasa de progresión son muy variables, lo que posiblemente sea explicado por las mutaciones presentes en el gen LIPA. Las manifestaciones clínicas son las mismas que para otras patologías hepáticas, cardiovasculares y metabólicas, lo que hace difícil reconocerla en la práctica clínica. Objetivo: proveer una guía que permita a los clínicos reconocer los principales grupos de riesgo en los cuales se debe sospechar de LAL-D y mejorar su diagnóstico. Metodología: este documento se diseñó como un consenso de expertos en el cual participaron médicos especialistas en gastroenterología, hepatología, endocrinología, genética, patología y pediatría. Se realizó una revisión de la literatura acerca de las manifestaciones clínicas y de las herramientas para el diagnóstico de LAL-D y se siguió la metodología de técnica de grupo nominal. Resultados: se generaron algoritmos diagnósticos por consenso para cada uno de los grupos de riesgo, que facilitaran la sospecha y el diagnóstico de LAL-D. Conclusiones: esta guía propone algoritmos para el diagnóstico de LAL-D con base en el consenso clínico, que buscan optimizar la ruta diagnóstica en los pacientes con dicha patología.


Abstract Introduction: Lysosomal acid lipase deficiency (LAL-D) is an inherited autosomal recessive entity that leads to the accumulation of cholesterol and triglyceride esters in the liver, spleen and other organs. The age of onset and rate of progression vary greatly, possibly explained by mutations of the LIPA gene. Clinical manifestations are the same as those of other hepatic, cardiovascular and metabolic pathologies which makes it difficult to recognize in clinical practice. Objective: The objectives of these guidelines is to help clinicians recognize the major groups at risk for LAL-D and to improve its diagnosis. Methodology: This document was designed as a consensus of experts in gastroenterology, hepatology, endocrinology, genetics, pathology and pediatrics. A review of the literature regarding clinical manifestations and tools for diagnosis of LAL-D was conducted and the nominal group technique was followed. Results: Diagnostic algorithms which facilitate suspicion and diagnosis of LAL-D were generated by consensus for each of the risk groups. Conclusions: This guide proposes algorithms for the diagnosis of LAL-D based on clinical consensus. The algorithms seek to optimize diagnosis for patients with this pathology.


Asunto(s)
Hiperlipoproteinemia Tipo I , Dislipidemias , Enfermedad de Wolman
10.
J. oral res. (Impresa) ; 5(5): 194-199, Aug. 2016. ilus, tab
Artículo en Inglés | LILACS | ID: biblio-907674

RESUMEN

Introduction: In recent decades, dental implants have become one of the best options for comprehensive dental restoration; their placement is a multidisciplinary task that requires a solid understanding of biological, periodontal, surgical and prosthetic principles. Objective: The aim of this study was to quantify in vitro the adhesion and proliferation of human gingival fibroblasts (HGF) response on titanium (Ti) and zirconia (Zr) surfaces. Methodology: Samples of Ti and Zr were observed under atomic force microscopy (AFM). HGFs were inoculated in each sample to determine adhesion and cell proliferation. The reagent MTT was mixed with medium DMEM and inoculated in each plate; formazan was dissolved with dimethyl sulfoxide and analyzed at 540nm in a microplate spectrophotometer. The test was performed with three independent experiments. Data were analyzed with Kolmogorov-Smirnov tests (Lilliefors), Kruskal-Wallis tests and Mann-Whitney test comparisons. Results: Topography of the Zr plates showed greater roughness (Ra= 0.39 microns) than Ti (Ra= 0.049 microns). Quantification of HGF adhesion was significantly higher (p<0.05) in Ti, while proliferation showed no statistically significant differences between the groups. Conclusion: It is noteworthy that, even though Ti initially showed increased cell adhesion on the surface, after 24h Zr samples showed similar proliferation; this demonstrates that both surfaces have a comparable biological response.


Introducción: En las últimas décadas, los implantes dentales se han posicionado como una de las mejores opciones de restauración dental integral; su colocación es una tarea multidisciplinaria que requiere una sólida comprensión de los principios biológicos, periodontales, quirúrgicos y protésicos. Objetivo: El objetivo de este estudio fue cuantificar in vitro la adhesión y proliferación de la respuesta de fibroblastos gingivales humanos (HGF) en superficies de titanio (Ti) en contraste con superficies de zirconia (Zr). Metodología: Se observaron las muestras de Ti y Zr bajo microscopía de fuerza atómica (AFM). Los HGF fueron inoculados en cada muestra para determinar la adhesión y proliferación celular. El reactivo MTT se mezcló con medio DMEM y se inoculó en cada placa, el formazán se disolvió con dimetilsulfóxido y se analizó a 540nm en un espectrofotómetro de microplaca. El ensayo se realizó con tres experimentos independientes. Los datos fueron analizados con pruebas de Kolmogorov-Smirnov (Lilliefors), pruebas de Kruskal-Wallis y comparaciones de Mann-Withney. Resultados: La topografía de las placas de Zr mostraron una mayor rugosidad (Ra=0.39 micrones) en comparación con las de Ti (Ra=0.049 micrones). La cuantificación de la adhesión de HGF fue significativamente mayor (p<0.05) en el Ti, mientras que la proliferación no mostró diferencias estadísticamente significativas entre los grupos. Conclusión: Es importante mencionar que, a pesar de que el Ti mostró inicialmente una mayor adhesión celular sobre la superficie, después de 24 hrs las muestras de Zr mostraron una proliferación similar; lo que demuestra que ambas superficies poseen una respuesta biológica comparable.


Asunto(s)
Materiales Biocompatibles , Adhesión Celular , Proliferación Celular , Implantes Dentales , Ensayo de Materiales , Propiedades de Superficie , Titanio/química , Circonio/química
12.
PLoS One ; 11(3): e0150660, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-26999791

RESUMEN

Sperm whales are present in the Canary Islands year-round, suggesting that the archipelago is an important area for this species in the North Atlantic. However, the area experiences one of the highest reported rates of sperm whale ship-strike in the world. Here we investigate if the number of sperm whales found in the archipelago can sustain the current rate of ship-strike mortality. The results of this study may also have implications for offshore areas where concentrations of sperm whales may coincide with high densities of ship traffic, but where ship-strikes may be undocumented. The absolute abundance of sperm whales in an area of 52933 km2, covering the territorial waters of the Canary Islands, was estimated from 2668 km of acoustic line-transect survey using Distance sampling analysis. Data on sperm whale diving and acoustic behaviour, obtained from bio-logging, were used to calculate g(0) = 0.92, this is less than one because of occasional extended periods when whales do not echolocate. This resulted in an absolute abundance estimate of 224 sperm whales (95% log-normal CI 120-418) within the survey area. The recruitment capability of this number of whales, some 2.5 whales per year, is likely to be exceeded by the current ship-strike mortality rate. Furthermore, we found areas of higher whale density within the archipelago, many coincident with those previously described, suggesting that these are important habitats for females and immature animals inhabiting the archipelago. Some of these areas are crossed by active shipping lanes increasing the risk of ship-strikes. Given the philopatry in female sperm whales, replacement of impacted whales might be limited. Therefore, the application of mitigation measures to reduce the ship-strike mortality rate seems essential for the conservation of sperm whales in the Canary Islands.


Asunto(s)
Navíos , Cachalote/fisiología , Animales , Organismos Acuáticos , Buceo/fisiología , Geografía , Densidad de Población , Probabilidad , España , Encuestas y Cuestionarios , Factores de Tiempo , Transportes
13.
Dent Res J (Isfahan) ; 13(6): 473-477, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-28182066

RESUMEN

BACKGROUND: The surface energy of titanium (Ti) implants is very important when determining hydrophilicity or hydrophobicity, which is vital in osseointegration. The purpose of this study was to determine how Ti plates with an alkaline treatment (NaOH) affect the adhesion and proliferation of human periodontal ligament fibroblasts (HPLF). MATERIALS AND METHODS: In vitro experimental study was carried out. Type 1 commercially pure Ti plates were analyzed with atomic force microscopy to evaluate surface roughness. The plates were treated ultrasonically with NaOH at 5 M (pH 13.7) for 45 s. HPLF previously established from periodontal tissue was inoculated on the treated Ti plates. The adhered and proliferated viable cell numbers were determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method for 60 min and 24 h, respectively. The data were analyzed using Kruskal-Wallis tests and multiple comparisons of the Mann-Whitney U-test,P value was fixed at 0.05. RESULTS: The mean roughness values equaled 0.04 µm with an almost flat surface and some grooves. The alkaline treatment of Ti plates caused significantly (P < 0.05) more pronounced HPLF adhesion and proliferation compared to untreated Ti plates. CONCLUSION: The treatment of Ti plates with NaOH enhances cell adhesion and the proliferation of HPLF cells. Clinically, the alkaline treatment of Ti-based implants could be an option to improve and accelerate osseointegration.

14.
Mar Environ Res ; 113: 56-61, 2016 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-26606106

RESUMEN

Intertidal mollusks are subjected to an intense environmental pressure, from human-induced stressors, mainly harvesting, to competition for food and space with other species. Here we used mollusk shell size as a measure of size distribution and reproductive potential of intertidal limpets. Two species of exploited limpets (Patella candei crenata and Patella aspera) were monitored throughout the littoral of Tenerife (Canary Islands, NE Atlantic Ocean), an overpopulated island with a high coastal pressure. The exploitation of these two limpet species is controlled by regional legislation, with seasonal closures and limits of harvest for professional (10 kg) and recreational harvesters (3-5 kg). A long-term comparison (1994-2014) of limpet size has been conducted as a surrogate of the state of conservation of these two limpets. Both species showed populations dominated largely by small-sized individuals (<30 mm) and a lack of large adults (>60 mm). The proximity to coastal settlements was not a factor to explain limpet assemblage structure. The temporal (1994-2014) comparative study showed a sharp decrease in the mean size of both limpet species (7 mm in P. aspera and 5 mm in P. candei crenata). These results might be indicative of overharvesting of both species in Tenerife. The conservation of the two studied species needs to be accomplished by the strict fulfillment of current protective strategies, as well as the creation of marine protected areas where intertidal harvesting is totally banned all over the year.


Asunto(s)
Monitoreo del Ambiente , Moluscos/fisiología , Animales , Explotaciones Pesqueras , Densidad de Población , España , Factores de Tiempo
16.
Beilstein J Nanotechnol ; 5: 1542-52, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25247136

RESUMEN

Copper sulfide is a promising p-type inorganic semiconductor for optoelectronic devices such as solar cells, due its small band gap energy and its electrical properties. In this work nanocrystalline copper sulfide (Cu x S), with two stoichiometric ratios (x = 2, 1.8) was obtained by one-pot synthesis at 220, 230, 240 and 260 °C in an organic solvent and amorphous Cu x S was obtained in aqueous solution. Nanoparticle-like nucleation centers are formed at lower temperatures (220 °C), mixtures of morphologies (nanorods, nanodisks and nanoprisms) are seen at 230 and 240 °C, in which the nanodisks are predominant, while big hexagonal/prismatic crystals are obtained at 260 °C according to TEM results. A mixture of chalcocite and digenite phases was found at 230 and 240 °C, while a clear transition to a pure digenite phase was seen at 260 °C. The evolution of morphology and transition of phases is consistent to the electrical, optical, and morphological properties of the copper sulfide. In fact, digenite Cu1.8S is less resistive (346 Ω/sq) and has a lower energy band gap (1.6 eV) than chalcocite Cu2S (5.72 × 10(5) Ω/sq, 1.87 eV). Low resistivity was also obtained in Cu x S synthesized in aqueous solution, despite its amorphous structure. All Cu x S products could be promising for optoelectronic applications.

17.
Ultrason Sonochem ; 20(2): 777-84, 2013 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-23099056

RESUMEN

In this work, hybrid nanocomposites based on anatase titania:polypyrrole (TiO(2):PPy) were directly obtained from a simple, one-step, ultrasonic (UT)-assisted synthesis. The properties of these crystalline nanocomposites were compared with those of others fabricated using cold (Cold)-assisted synthesis without any UT assistance, which required a hydrothermal treatment (HT) to yield crystalline anatase titania in the nanocomposite (TiO(2):PPy) at low temperature (130°C) and in a short time (3h). The SEM results demonstrated that the UT-assisted synthesis is a feasible method to obtain anatase TiO(2):PPy nanocomposites with controlled morphology using low energy. The Fourier transform infrared (FT-IR) bands of the crystalline nanocomposites exhibited a shift with respect to neat components, which was attributed to the strong interaction between the secondary amine groups (N-H) of PPy and the oxygen from TiO(2). The acceptable absorption in the visible region (λ(max)=670nm) indicates that these nanocomposites are good candidates for harvesting energy in solar cells. Devices based on these nanocomposites were built to evaluate their electrical properties. An increase in the photocurrent was observed for the devices prepared with the nanocomposites from the UT-assisted synthesis.

18.
Rev. oftalmol. venez ; 45(4): 268-72, oct.-dic. 1987. ilus
Artículo en Español | LILACS | ID: lil-59451

RESUMEN

Se reporta un caso de oftalmomiasis orbitaria en paciente M de 25 años de edad, a quien se le realiza injerto libre de piel total proveniente del muslo en la región fronto-parieto-temporal y orbitaria izquierda, obteniéndose resultado satisfactorio


Asunto(s)
Adulto , Humanos , Masculino , Larva Migrans/etiología , Miasis/terapia
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