217 research outputs found
Papel de la enfermería en la detección de factores de riesgo en exploraciones radiológicas con contraste: TC-RM
Introducción:
La administración de los medios de contrastes (MC) para el diagnóstico y control oncológico es rutinaria, utilizándose como técnicas de diagnóstico la TC vs RM.Este contraste se ha asociado a aumento de morbilidad y mortalidad, por lo que es fundamental identificar factores de riesgo previo al TC y/o RM con cuestionarios administrados por enfermería a pacientes oncológicos, valorando el daño renal a través del filtrado glomerular y el desenlace del paciente.
Material y métodos
El comité de Ética de investigación aprobó el estudio. Estudio prospectivo observacional de ámbito
hospitalario. Incluye 507 pacientes que se realiza TC vs RM entre marzo y mayo del 2017. Todos rellenaron el cuestionario de la European Society of Urogenital Radiology (ESUR) modificado y tenían un Filtrado Glomerular estimado (IFGe) >30 ml/min./1,73 m2, el día de la exploración. Fueron seguidos durante un período de cuatro a 24 meses registrando toda su información clínica. Se realizó el estudio estadístico univariante y de regresión logística. Se dicotomizó el FG en dos grupos: estable-mejora vs empeora.
Resultados
En la regresión logística, las únicas variables estadísticamente asociadas al deterioro de IFGe son
edad, (OR=1,091; p< 0,001), sexo femenino, (OR=0,021) e hipertensión arterial (HTA), (OR=3,68, p=0,002). Para el evento exitus solo el grupo de empeora su FG se mostró más cercano a la significación estadística con predictor (OR=2,69, P=0,024)
Conclusiones
La administración de contrastes iodados y/o de gadolinio en pacientes oncológicos, no está asociada a un incremento de daño renal en el seguimiento de 24 meses. Son factores de riesgo asociado a un deterioro del IFGe, no clínicamente significativo tras contraste, edad, sexo masculino e HTA. El deterioro del IFGe posterior a la administración contraste, se produce en aquellos pacientes con valores basales IFGe>60 ml/min/1.73m2. La baja prevalencia de RA, indican la seguridad de los MCI y MCBG en pacientes oncológicos. Los cuestionarios administrados por enfermería pueden detectar factores de riesgo independientes de su neoplasia. El equipo mutidisciplinar, debe de ser consciente de los escasos efectos secundarios del contraste iodado y/o de gadolinio, y considerar estrategias de reducción de los mismos.EnfermeríaCiencias de la Salu
Evidence for Blue Straggler Stars Rejuvenating the Integrated Spectra of Globular Clusters
Integrated spectroscopy is the method of choice for deriving the ages of
unresolved stellar systems. However, hot stellar evolutionary stages, such as
hot horizontal branch stars and blue straggler stars (BSSs), can affect the
integrated ages measured using Balmer lines. Such hot, "non-canonical" stars
may lead to overestimations of the temperature of the main sequence turn-off,
and therefore underestimations of the integrated age of a stellar population.
Using an optimized Hbeta index in conjunction with HST/WFPC2 color-magnitude
diagrams (CMDs), we show that Galactic globular clusters exhibit a large
scatter in their apparent "spectroscopic" ages, which does not correspond to
that in their CMD-derived ages. We find for the first time that the specific
frequency of BSSs, defined within the same aperture as the integrated spectra,
shows a clear correspondence with Hbeta in the sense that, at fixed
metallicity, higher BSS ratios lead to younger "apparent" spectroscopic ages.
Thus, the specific frequency of BSSs in globular clusters sets a fundamental
limit on the accuracy for which spectroscopic ages can be determined for
globular clusters, and maybe for other stellar systems like galaxies. The
observational implications of this result are discussed.Comment: 5 pages, 2 figures, 1 table. Accepted for publication in ApJ
Synthesis and characterization of calcium hydroxide obtained from agave bagasse and investigation of its antibacterial activity
ABSTRACT
Calcium hydroxide (Ca(OH)2) is recognized as an efficient bactericide and is widely
applied as a root canal filler in endodontic treatment. Ca(OH)2 is mainly produced by
hydration of calcium oxide (CaO), a product of the thermal decomposition of calcium
carbonate (CaCO3) from sources such as limestone. In this work, calcium hydroxide
particles were synthetized by the thermochemical transformation of waste biomass
from the tequila industry. Agave biomass processed at 600 °C was composed mostly
of calcium carbonate (CaCO3), while calcination at 900 °C followed by hydration
produced Ca(OH)2. The morphology and crystalline nature of the Ca(OH)2 particles
were characterized by micro-Raman spectroscopy, scanning electron microscopy and
X-ray diffraction analysis. Bactericidal activity of synthesized calcium hydroxide was
evaluated with the agar diffusion assay. Our results provide evidence that Ca(OH)2
obtained from agave biomass is an effective bactericidal against Escherichia coli and
Enterococcus faecalis. Biomass from agave is available in Mexico and the rest of
the American continent, the use of processed bagasse for medical applications could
provide a venue for the useful disposition of industrial waste.
Palabras clave: recursos renovables, ceniza, bactericida, Ca(OH)2
RESUMEN
El hidróxido de calcio (Ca(OH)2) es reconocido como un eficiente bactericida y es
ampliamente utilizado como relleno de la raíz dental en tratamientos de endodoncia.
El Ca(OH)2 es producido por la hidratación del óxido de calcio (CaO), un producto de
la descomposición térmica del carbonato de calcio (CaCO3), obtenido principalmente
de piedra caliza. En el presente trabajo, se sintetizaron partículas de hidróxido de calcio
mediante la descomposición térmica de biomasa residual de la industria tequilera. La
biomasa de agave se procesó a 600 °C, la cual se compone principalmente de carbonato
de calcio (CaCO3), por lo que su calcinación a 900 °C y posterior hidratación producen
el Ca(OH)2. La morfología y cristalinidad de las partículas de Ca(OH)2 se caracterizaron mediante el uso de espectroscopía Raman, microscopio electrónico de barrido
y difracción de rayos X. La actividad bactericida del hidróxido de calcio obtenido, se
evaluó mediante el ensayo de difusión en agar. Los resultados proveen evidencia de
la efectividad del Ca(OH)2, obtenido de la biomasa de agave, contra Escherichia coli
y Enterococcus faecalis. La biomasa de agave se encuentra ampliamente disponible
en México y el resto del continente americano, por lo que el uso de bagazo de agave
procesado en aplicaciones médicas, puede proveer una alternativa en la disposición y
el uso de residuos agroindustriales
Women facing psychological abuse: how do they respond to maternal identity humiliation and body shaming?
This research analyzes the decisions made by women facing simulated situations of psychological abuse. Seventy-three women (36.9 ± 13.6 years) who had been victims of domestic violence participated. The analysis was based on their coping strategies, early maladaptive schemes, and their decisions in response to vignettes describing the following domestic violence situations: humiliation to women’s maternal identity with children as witnesses and body shaming. We used Student’s t and Mann–Whitney tests to compare the results between groups. The participants presented some coping strategies (social support seeking, wishful thinking, and professional support seeking) and several early maladaptive schemes (emotional deprivation, defectiveness/shame, social isolation/alienation, failure to achieve, attachment, and subjugation) associated with their reactions facing a situation of humiliation with children as witnesses. When the humiliation was against the body image, their reactions were associated with some coping strategies (wishful thinking, professional support seeking, autonomy, negative auto-focus coping, and positive reappraisal) and one maladaptive scheme (defectiveness/shame). Women who reacted avoidantly showed higher social and professional support seeking but experienced higher indicators of discomfort and deterioration of self-esteem than those who opted for assertive decisions. The presence of children as witnesses seems to be a factor of stress in the configuration of coping strategies and maladaptive schemes in female victims of domestic violence. The evolution of early maladaptive schemes and coping strategies requires observation to avoid the risk of isolation and permanence in victimizing relationships
Desarrollo de un modelo de perfil de copa para Pinus cooperi Blanco en la UMAFOR 1008, Durango, México
A crown profile model for Pinus cooperi Blanco in UMAFOR 1008 (El Salto, Pueblo Nuevo,
Durango) was developed from data corresponding to 92 sampled trees. Trees with
well-formed crowns were selected from stands varying in age, density and site quality.
Diameter at breast height, total height, crown width, crown length, and crown profile were
measured in each tree. To predict the crown profile, basic geometric shapes and several
mathematic models were evaluated. The model developed by Hann (1999) best described the experimental data of the total crown, light crown, and shaded crown, accounting for over
92 % of the observed variability.Se desarrolló un modelo de perfil de copa para Pinus cooperi Blanco a partir de 92
árboles en la UMAFOR 1008 (Región El Salto, Pueblo Nuevo, Durango). Se seleccionaron
individuos con una copa bien conformada y de diferente edad, densidad y calidad de
estación. En cada uno de los individuos se midieron las variables diámetro normal, altura
total, diámetro, longitud y perfil de copa. Tanto formas geométricas sencillas como algunos
modelos matemáticos se analizaron para predecir el perfil de la copa. El mejor modelo para
describir el perfil de copa de P. cooperi fue el de Hann (1999), ya que tuvo mejor ajuste
para la copa entera, copa de luz y copa de sombra, explicando más de 92 % de la variabilidad de los datos.S
Influence of Laser Modulation Frequency on the Performance of Terahertz Photoconductive Switches on Semi-Insulating GaAs Exhibiting Negative Differential Conductance
[EN]In typical terahertz time-domain spectroscopy systems, the use of the lock-in technique is necessary because of the low current induced at the receiver so that the laser pump beam must be modulated (chopped) at a frequency much lower than the laser repetition rate. This work shows that, in the case of semi-insulating GaAs (SI-GaAs) antennas, this modulation has an important effect on the antenna current and consequently, on the radiated electromagnetic pulse. There exists a threshold bias (whose value depends on the chopping frequency) where an abrupt increase in the current and consequently, in the terahertz emission takes place. The calculated energy of the pulse below and above the threshold shows that the energy doubles. The exact bias voltage at which this occurs changes with the laser modulation frequency when this is below 350 Hz, but at higher frequencies, the threshold remains almost constant. The experiments show that the responsibility for this behavior is the S-shape negative differential conductance exhibited by SI-GaAs originated by a slow field-enhanced charge trapping mechanism, which is also an important source of noise at the receiver of the system.SpanishMINECO and FEDER under Project TEC2017-83910-R and in Junta de Castilla y León and FEDER
under Project SA254P1
Evaluación de la resistencia a la corrosión de un acero fabricado por manufactura aditiva mediante técnicas electroquímicas
Additive metal manufacturing has undergone a revolution in recent years, being able to be incorporated in several industries such as aeronautics, automotive and even in medicine, allowing the manufacture of complex parts with fewer steps in the process, which translates in material savings and cost reduction. In this work, the corrosion of low carbon steel obtained by depositing consecutive layers is carried out, using electrochemical impedance spectroscopy and electrochemical noise immersed in a 0.1 M NaCl solution, establishing a comparison between the metal of contribution and deposited material. The layers of the material are characterized microstructurally and mechanically using scanning electron microscopy and Vickers microhardness. Overall, the results show a good response of the material to the action of the electrolyte after the immersion time, on the other hand, the microstructural results allow identifying the formation of 3 zones due to the cooling of the material. The microhardness of the steel does not show great changes between the zones, however, there is a slight increase in the intermediate zone due to the reduction in grain size. These studies allow researchers to know the behavior of these materials in applications that require contact with corrosive solutions of this nature.La manufactura aditiva de metales ha sufrido una revolución en los últimos años, pudiéndose incorporar en diversas industrias como la aeronáutica, automotriz e incluso en la medicina, permitiendo la fabricación de partes complejas con un menor número de pasos en el proceso, lo que se traduce en ahorro de material y reducción de costos. En este artículo se realiza el monitoreo del estado de corrosión de un acero de bajo carbono obtenido mediante la deposición de capas consecutivas, evaluándose a través de la técnica de impedancia electroquímica y ruido electroquímico, inmerso en una solución 0.1 M de NaCl, estableciendo una comparativa entre el metal de aporte y el material depositado. Las capas del material son caracterizadas microestructural y mecánicamente mediante microscopía electrónica de barrido y microdureza Vickers. De forma global, los resultados muestran una buena respuesta del material ante la acción del electrolito transcurrido el tiempo de inmersión, Por otro lado, los resultados microestructurales permiten identificar la formación de 3 zonas debido al enfriamiento en gradiente del material. La microdureza del acero no muestra grandes cambios entre las zonas, sin embargo, hay un ligero aumento en la zona intermedia debido a la reducción en el tamaño del grano. Estos estudios permiten a investigadores conocer el comportamiento de estos materiales en aplicaciones que demanden el contacto con soluciones corrosivas de esta naturaleza
Monitoreo del consumo de agua para evitar desperdicio
En este trabajo se explica el monitoreo el consumo de agua para detectar pérdidas en tuberías y desperdicio de agua mediante medidores de flujo. Usando sensores ultrasónicos se puede realizar la medición de niveles de agua en cisternas y tinacos. Para posteriormente mediante sensores de flujo monitorear el estado del flujo del agua y detectar fugas en el sistema
Facile synthesis of low band gap ZnO Microstructures
Abstract In this work a simple chemical route was employed to synthesize ZnO microparticles by precipitation from aqueous solution of ZnCl2 as precursor, NaOH as oxidizing and sodium dodecyl sulfate (SDS) as surfactant. Samples of ZnO microparticles were analyzed by scanning electron microscopy (SEM), FTIR spectroscopy, Raman spectroscopy, X-Ray diffraction, UV/Vis-NIR diffusereflectance,highresolutiontransmissionelectronmicroscopy(HR-TEM),andN2 adsorption-desorption.Itwasobserved from SEM analysis that ZnO microparticles with morphologies resembling six-blade impeller with diameters in the range of 500 nm to 1 m, and sheet-like (approximately 200 nm×300 nm) were obtained through this technique. X-Ray diffraction and Raman analyses confirmed the obtaining of hexagonal wurtzite ZnO crystal structure. The calculated band gap energy was 3.19 eV, which is slightly lower than the average value reported in the literature. Specific BET area of ZnO microparticles was 26.5 m2/g. Keywords: ZnO, microstructures, band gap energy, SEM, morphology.
Resumen En este trabajo se empleó un a ruta química sencilla para sintetizar micropartículas de ZnO mediante precipitación en solución acuosa de ZnCl2 como precursor, NaOH como oxidante y dodecil sulfato de sodio (SDS) como tensoactivo. Las muestras de ZnO fueron analizadas mediante microscopía de barrido electrónico (SEM), espectroscopía de FTIR, espectroscopía Raman, difracción de rayos-X, reflectancia difusa de UV/Vis-NIR, microscopía de transmisión de electrones de alta resolución (HRTEM), y mediante adsorción-desorción de N2. Se observó mediante análisis de SEM que mediante esta técnica se obtienen micropartículas de ZnO con morfologías similares a impulsores de seis-aspas con diámetros entre 500 nm y 1 m, morfologías tipo-hojas(deaproximadamente200nm×300nm).Losanálisisdedifracciónderayos-XydeRamanconfirmaronlaobtención de ZnO con estructura cristalina wurtzita hexagonal. La energía de band gap calculada fue de 3.19 eV, la cual es ligeramente menor que el valor promedio reportado en la literatura. El área superficial BET de las nanopartículas de ZnO fue de 26.5 m2/g Palabras clave: ZnO, microestructuras, energía de band gap, SEM, morfología
Anaerobic methane oxidation driven by microbial reduction of natural organic matter in a tropical wetland
"Wetlands constitute the main natural source of methane on Earth due to their high content of natural organic matter (NOM), but key drivers, such as electron acceptors, supporting methanotrophic activities in these habitats are poorly understood. We performed anoxic incubations using freshly collected sediment, along with water samples harvested from a tropical wetland, amended with C-13-methane (0.67 atm) to test the capacity of its microbial community to perform anaerobic oxidation of methane (AOM) linked to the reduction of the humic fraction of its NOM. Collected evidence demonstrates that electron-accepting functional groups (e.g., quinones) present in NOM fueled AOM by serving as a terminal electron acceptor. Indeed, while sulfate reduction was the predominant process, accounting for up to 42.5% of the AOM activities, the microbial reduction of NOM concomitantly occurred. Furthermore, enrichment of wetland sediment with external NOM provided a complementary electron-accepting capacity, of which reduction accounted for similar to 100 nmol (CH4)-C-13 oxidized center dot cm(3)center dot day(1). Spectroscopic evidence showed that quinone moieties were heterogeneously distributed in the wetland sediment, and their reduction occurred during the course of AOM. Moreover, an enrichment derived from wetland sediments performing AOM linked to NOM reduction stoichiometrically oxidized methane coupled to the reduction of the humic analogue anthraquinone-2,6-disulfonate. Microbial populations potentially involved in AOM coupled to microbial reduction of NOM were dominated by divergent biota from putative AOM-associated archaea. We estimate that this microbial process potentially contributes to the suppression of up to 114 teragrams (Tg) of CH(4 center dot)year(-1) in coastal wetlands and more than 1,300 Tg center dot year(-1), considering the global wetland area.
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