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1.
Artículo en Inglés | MEDLINE | ID: mdl-37946064

RESUMEN

Research has demonstrated erosion of empathy in students during medical education. Particularly, U.S. studies have demonstrated empathy declines during clinical training in the third and fourth year of traditional medical programs. Yet, studies conducted outside the U.S. have not confirmed this trend. Timing and extent of patient interactions have been identified as empathy-protective factors. The need to examine empathy within different learning contexts has been noted, as has the need for longitudinal and time-series research designs to analyze trajectories. Between fall 2010 and spring 2019, we assessed empathy longitudinally among six student cohorts (N = 493) at a U.S. medical school, where patient interaction occurs early and throughout an integrated curriculum. Empathy levels of students in each cohort were assessed at five time points utilizing the Jefferson Scale of Physician Empathy-Student version. We hypothesized empathy levels will not degrade by program end, and trajectories will not show patterns of decline in Years Three and Four. Analysis of Variance (ANOVA) and Linear Mixed Model (LMM) analyses were used to analyze differences at baseline and changes in empathy trajectories. ANOVA analyses revealed statistically significant differences at baseline by class cohort (F(5, 487) = [23.28], p < 0.001). LMM analyses indicated empathy was either significantly higher or not different at the end of the program (F(19, 1676) = [13.97], p < 0.001). Empathy trajectories varied among cohorts; yet, none resulted in an overall empathy decline by the end of the program. Findings demonstrate empathy in U.S. medical students can be unchanged or higher by the end of medical education. Outcomes are consistent with reports of non-declining medical student empathy outside the U.S. and support the notion of context-specificity. Results further support recent research, suggesting decreases in empathy during training can stabilize or increase by program end. These findings have important implications for future empathy research context and design considerations, as well as program planning.

2.
Mol Med ; 28(1): 131, 2022 11 08.
Artículo en Inglés | MEDLINE | ID: mdl-36348276

RESUMEN

BACKGROUND: Respiratory failure in severe coronavirus disease 2019 (COVID-19) is associated with a severe inflammatory response. Acetylcholine (ACh) reduces systemic inflammation in experimental bacterial and viral infections. Pyridostigmine increases the half-life of endogenous ACh, potentially reducing systemic inflammation. We aimed to determine if pyridostigmine decreases a composite outcome of invasive mechanical ventilation (IMV) and death in adult patients with severe COVID-19. METHODS: We performed a double-blinded, placebo-controlled, phase 2/3 randomized controlled trial of oral pyridostigmine (60 mg/day) or placebo as add-on therapy in adult patients admitted due to confirmed severe COVID-19 not requiring IMV at enrollment. The primary outcome was a composite of IMV or death by day 28. Secondary outcomes included reduction of inflammatory markers and circulating cytokines, and 90-day mortality. Adverse events (AEs) related to study treatment were documented and described. RESULTS: We recruited 188 participants (94 per group); 112 (59.6%) were men; the median (IQR) age was 52 (44-64) years. The study was terminated early due to a significant reduction in the primary outcome in the treatment arm and increased difficulty with recruitment. The primary outcome occurred in 22 (23.4%) participants in the placebo group vs. 11 (11.7%) in the pyridostigmine group (hazard ratio, 0.47, 95% confidence interval 0.24-0.9; P = 0.03). This effect was driven by a reduction in mortality (19 vs. 8 deaths, respectively). CONCLUSION: Our data indicate that adding pyridostigmine to standard care reduces mortality among patients hospitalized for severe COVID-19.


Asunto(s)
Tratamiento Farmacológico de COVID-19 , Adulto , Masculino , Humanos , Persona de Mediana Edad , Femenino , Bromuro de Piridostigmina/uso terapéutico , SARS-CoV-2 , Respiración Artificial , Inflamación , Resultado del Tratamiento
3.
Proc Natl Acad Sci U S A ; 115(28): E6556-E6565, 2018 07 10.
Artículo en Inglés | MEDLINE | ID: mdl-29950315

RESUMEN

Macrophages are key immune cells for the initiation and development of atherosclerotic lesions. However, the macrophage regulatory nodes that determine how lesions progress in response to dietary challenges are not fully understood. Liver X receptors (LXRs) are sterol-regulated transcription factors that play a central role in atherosclerosis by integrating cholesterol homeostasis and immunity. LXR pharmacological activation elicits a robust antiatherosclerotic transcriptional program in macrophages that can be affected by LXRα S196 phosphorylation in vitro. To investigate the impact of these transcriptional changes in atherosclerosis development, we have generated mice carrying a Ser-to-Ala mutation in myeloid cells in the LDL receptor (LDLR)-deficient atherosclerotic background (M-S196ALdlr-KO). M-S196ALdlr-KO mice fed a high-fat diet exhibit increased atherosclerotic plaque burden and lesions with smaller necrotic cores and thinner fibrous caps. These diet-induced phenotypic changes are consistent with a reprogramed macrophage transcriptome promoted by LXRα-S196A during atherosclerosis development. Remarkably, expression of several proliferation-promoting factors, including the protooncogene FoxM1 and its targets, is induced by LXRα-S196A. This is consistent with increased proliferation of plaque-resident cells in M-S196ALdlr-KO mice. Moreover, disrupted LXRα phosphorylation increases expression of phagocytic molecules, resulting in increased apoptotic cell removal by macrophages, explaining the reduced necrotic cores. Finally, the macrophage transcriptome promoted by LXRα-S196A under dietary perturbation is markedly distinct from that revealed by LXR ligand activation, highlighting the singularity of this posttranslational modification. Overall, our findings demonstrate that LXRα phosphorylation at S196 is an important determinant of atherosclerotic plaque development through selective changes in gene transcription that affect multiple pathways.


Asunto(s)
Aterosclerosis/metabolismo , Proteína Forkhead Box M1/biosíntesis , Regulación de la Expresión Génica , Receptores X del Hígado/metabolismo , Macrófagos/metabolismo , Mutación Missense , Sustitución de Aminoácidos , Animales , Aterosclerosis/genética , Aterosclerosis/patología , Proliferación Celular , Proteína Forkhead Box M1/genética , Receptores X del Hígado/genética , Macrófagos/patología , Ratones , Ratones Noqueados , Fosforilación
4.
J Environ Manage ; 254: 109832, 2020 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-31733480

RESUMEN

The chemical evolution of brines resulting from an inactive phosphogypsum pond derived of fertilizer industry located in Huelva (Spain, SW Europe) has been studied based on a weekly sampling from 2014 to 2017. Long-range time variation of metals and ions concentrations in brines are expected to depend on environmental parameters such as rainfall and evaporation. The results show that brines are enriched in F- (1.7-2.0 g/l), Cl- (13-24 g/l), SO42- (7.2-9.3 g/l), V (70-128 mg/l) and U (55-98 mg/l). A great variation of chemical concentrations has been found, due to dilution, recharge and evaporation processes. Most of the elements show peak concentrations in summer, coinciding with the lowest pH values (<1), high conductivity (>133 mS/cm), and high evaporation rates as expected. Nonetheless, F- shows an opposite behaviour, varying its concentrations between 0.9 g/l in summer and 3.7 g/l in the rainy season. According to the results, a future restoration plan for PG ponds should include the removal of brines and layered salts during summer in order to avoid the annual generation of brines and their impact on the environment.


Asunto(s)
Estanques , Contaminantes Químicos del Agua , Sulfato de Calcio , Europa (Continente) , Fósforo , Sales (Química) , España
6.
Genet Mol Res ; 13(3): 7571-6, 2014 Sep 12.
Artículo en Inglés | MEDLINE | ID: mdl-25222257

RESUMEN

We examined cross-species transferability and usefulness of six nuclear microsatellite markers developed in consubgeneric eastern white pine (Pinus strobus) with regard to ecologically and commercially important Mexican white pine species of conservation genetics concern: Pinus chiapensis (Mart.) Andresen, P. flexilis James, P. strobiformis Engelm., P. ayacahuite Ehrenb. Ex Schltdl, and P. ayacahuite var. veitchii (Roezl) G.R. Shaw. Four to six microsatellite loci were found to be polymorphic in different species, with moderate to high informativeness in a relatively small number of samples (PIC/HE=0.25-0.93). This successful transfer sidesteps the time- and resource-consuming development of species-specific microsatellite markers, and will facilitate population and conservation genetic studies and genetic resource management of the less studied Mexican white pines.


Asunto(s)
Cruzamientos Genéticos , Repeticiones de Microsatélite , Pinus/genética , Sitios Genéticos , Genética de Población , México , Polimorfismo Genético
7.
Sci Total Environ ; 946: 174317, 2024 Oct 10.
Artículo en Inglés | MEDLINE | ID: mdl-38960189

RESUMEN

Lignin is an abundant and recalcitrant biopolymer of major relevance as soil organic matter (SOM) component playing a significant role in its stabilization. In this work, a factorial field experiment was established, where three climatic treatments (W, warming; D, drought; W + D, warming + drought), mimicking future climate change scenarios were installed over five years in a Mediterranean savannah "dehesa", accounting for its landscape diversity (under the tree canopy and in open grassland). A combination of analytical pyrolysis (Py-GC/MS) and the study of biogeochemical proxies based on lignin monomers is used for the direct detection of lignin-derived phenols and to infer possible shifts in lignin dynamics in soil. A total of 27 main lignin-derived methoxyphenols were identified, exhibiting different patterns and proportions, mainly driven by the effect of habitat, hence biomass inputs to SOM. An accelerated decomposition of lignin moieties -(exhibited by higher LG/LS and Al/K + Ac ratios)- is particularly exacerbated by the effect of all climatic treatments. There is also an overall effect on increasing lignin oxidation of side chain in syringyl units, especially under the tree canopy due to the alteration in biomass degradation and potential stimulation of enzyme activities. Conversely, in open grassland these effects are slower since the microbial community is expected to be already adapted to harsher conditions. Our findings suggests that climate change-related temperature and soil moisture deviations impact soil lignin decomposition in dehesas threatening this productive Mediterranean agroecosystem and affecting the mechanism of soil carbon storage.

8.
J Environ Radioact ; 278: 107499, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39079350

RESUMEN

Certified reference material (CRM) for natural (40K,210Pb,210Po,226Ra,228Ra,228Th,230Th,232Th,234U,235U, and238U) and anthropogenic (137Cs,239+240Pu, and241Am) radionuclides in marine sediment from the Baltic Sea (IAEA-465) has been developed. Information values are given for 238Pu,239Pu and240Pu. Altogether 27 laboratories participated in this exercise. Radiometric (alpha-spectrometry, gamma-spectrometry and beta counting, as well as mass spectrometry (ICP-MS and AMS) techniques were applied in measurements. The CRM is intended to be used for Quality Assurance/Quality Control of radionuclide analyses, for the development and validation of analytical methods, for the development of reference methods and for training purposes.


Asunto(s)
Sedimentos Geológicos , Monitoreo de Radiación , Contaminantes Radiactivos del Agua , Sedimentos Geológicos/química , Contaminantes Radiactivos del Agua/análisis , Plutonio/análisis , Estándares de Referencia , Radioisótopos/análisis , Radioisótopos de Cesio/análisis , Torio/análisis
9.
Rev Neurol ; 77(1): 13-18, 2023 07 01.
Artículo en Inglés, Español | MEDLINE | ID: mdl-37365720

RESUMEN

AIM: The objective of this study is to evaluate effects of SARS-CoV-2 vaccination on seizure pattern in paediatric patients with epilepsy that attended our tertiary center in the city of Bogota, Colombia. PATIENTS AND METHODS: Children with epilepsy who were treated at our center and have had SARS-CoV-2 vaccination and their caregivers were asked to report their experience following vaccination. We documented age, sex, age at onset of epilepsy, duration of epilepsy, epilepsy type, seizure frequency, number of medications, time from last crisis, vaccination schemes, and seizures two weeks after vaccination. RESULTS: One hundred and one patients with epilepsy were included (58%, male; and 42%, female). The average age was 11 years, 73% had focal epilepsy, and 27%, generalized. Twenty-one fulfilled criteria for refractory epilepsy and 11 had a personal history of febrile seizures. Forty-seven patients had been vaccinated with Sinovac's vaccine; 41 patients, with Pfizer's; 12 patients, with Moderna's; and one, with CoronaVac's. Three patients presented seizures 24 hours after the application of the vaccine with no clear relation between vaccination and seizure frequency, and one patient required admission to the hospital for a prolonged seizure. CONCLUSION: Vaccination against SARS-CoV-2 in paediatric patients with epilepsy is safe. Approximately 3% of patients with epilepsy could eventually have seizures in the post-vaccination period.


TITLE: Vacunación contra el SARS-CoV-2 en pacientes pediátricos con epilepsia: experiencia de un centro terciario en Colombia.Objetivo. El objetivo de este estudio es evaluar los efectos de la vacunación contra el SARS-CoV-2 sobre el patrón convulsivo en pacientes pediátricos con epilepsia que acudieron a nuestro centro terciario en la ciudad de Bogotá, Colombia. Pacientes y métodos. Se pidió a los niños con epilepsia que fueron tratados en nuestro centro y que habían recibido la vacuna contra el SARS-CoV-2 y a sus cuidadores que informaran de su experiencia después de la vacunación. Se documentaron la edad, el sexo, la edad de inicio de la epilepsia, la duración de la epilepsia, el tipo de epilepsia, la frecuencia de las convulsiones, el número de medicamentos, el tiempo transcurrido desde la última crisis, los esquemas de vacunación y las convulsiones dos semanas después de la vacunación. Resultados. Se incluyó a 101 pacientes con epilepsia (58%, hombres; y 42%, mujeres). La edad promedio fue de 11 años, el 73% tenía epilepsia focal, y el 27%, generalizada. Veintiuno cumplían los criterios para la epilepsia refractaria y 11 tenían antecedentes personales de convulsiones febriles. Cuarenta y siete pacientes habían sido vacunados con la vacuna de Sinovac; 41, con Pfizer; 12, con Moderna; y uno, con CoronaVac. Tres pacientes presentaron convulsiones 24 horas después de la aplicación de la vacuna sin una relación clara entre la vacunación y la frecuencia de las convulsiones, y un paciente requirió ingreso en el hospital por una convulsión prolongada. Conclusión. La vacunación contra el SARS-CoV-2 en pacientes pediátricos con epilepsia es segura. Aproximadamente el 3% de los pacientes con epilepsia podría eventualmente tener convulsiones en el período posterior a la vacunación.


Asunto(s)
COVID-19 , Epilepsia , Estado Epiléptico , Niño , Humanos , Masculino , Femenino , Recién Nacido , Vacunas contra la COVID-19 , Colombia , SARS-CoV-2 , COVID-19/prevención & control , Vacunación
10.
J Environ Monit ; 13(5): 1276-87, 2011 May.
Artículo en Inglés | MEDLINE | ID: mdl-21437327

RESUMEN

A long-term series (2001-2008) of chemical analysis of atmospheric particulate matter (PM(10) and PM(2.5)) collected in the city of Huelva (SW Spain) is considered in this study. The impact of emission plumes from one of the largest Cu-smelters in the world on air quality in the city of Huelva is evidenced by the high daily and hourly levels of As, other potentially toxic elements (e.g. Cu, Zn, Cd, Se, Bi, and Pb) in particulate matter, as well as the high levels of some gaseous pollutants (NO(2) and SO(2)). Mean arsenic levels in the PM10 fraction were higher than the target value set by European Directive 2004/107/EC (6 ngAs m(-3)) for 1(st) January 2013. Hourly peak concentrations of As and other metals and elements (Zn, Cu, P and Se) analyzed by PIXE can reach maximum hourly levels as high as 326 ngAs m(-3), 506 ngZn m(-3), 345 ngCu m(-3), 778 ngP m(-3) and 12 ngSe m(-3). The contribution of Cu-smelter emissions to ambient PM is quantified on an annual basis in 2.0-6.7 µg m(-3) and 1.8-4.2 µg m(-3) for PM(10) and PM(2.5), respectively. High resolution outputs of the HYSPLIT dispersion model show the geographical distribution of the As ambient levels into the emission plume, suggesting that the working regime of the Cu-smelter factory and the sea breeze circulation are the main factors controlling the impact of the Cu-smelter on the air quality of the city. The results of this work improve our understanding of the behaviour of industrial emission plumes and their impact on air quality of a city, where the population might be exposed to very high ambient concentrations of toxic metals during a few hours.


Asunto(s)
Contaminantes Atmosféricos/análisis , Cobre/análisis , Material Particulado/análisis , Contaminantes Atmosféricos/química , Ciudades , Cobre/química , Monitoreo del Ambiente , Residuos Industriales/análisis , Residuos Industriales/estadística & datos numéricos , Metalurgia/estadística & datos numéricos , Material Particulado/química , España
11.
Sci Total Environ ; 761: 143219, 2021 Mar 20.
Artículo en Inglés | MEDLINE | ID: mdl-33189378

RESUMEN

High severity wildfires cause a drastic alteration of soil carbon cycling - both oxidising and thermally altering soil organic matter (SOM) - and usually are followed by strong runoff and erosion events. To restore wildfire-degraded soils, SOM needs to be rebuilt while soil erosion is prevented. Post-fire straw mulching has been shown to mitigate soil erosion by providing a protective cover against rainsplash. However, SOM takes many decades or centuries to rebuilt naturally. Biochar, co-applied with straw to the soil surface can replace the SOM of the O-horizon, while the stabilised soil - by straw mulching - may gain in SOM naturally and by downward movement of biochar. We conducted a field study to test if straw-only and straw-biochar co-application could restore soils degraded by wildfire in one high burn severity (HBS) and one moderate burn severity (MBS) study area in southern Portugal and Spain, respectively, by monitoring erosion and SOM for the most intense rainfall period of the first post-fire year. Burned sites were characterized for soil and sediment physical properties, TOC content, SOM quality by thermogravimetry (DTG) and nuclear magnetic resonance (NMR 13C) spectroscopy. Straw-biochar mulching significantly reduced soil erosion by 76% and 65% in the HBS and MBS sites, respectively, in both cases similar to the erosion reduction by straw-only mulching. DTG and NMR 13C indicated that a relatively small proportion of the biochar eroded, i.e. 0.7%, indicating that co-application of straw with biochar may help restore the SOC lost in the wildfire in the medium term. The amount of SOM eroded was lower with straw-biochar mulching than in the untreated plots for both study areas. Straw-biochar mulching mitigates erosion of wildfire-degraded soils under extreme rainfall, while a relatively small proportion of the biochar is lost by erosion. Future studies need to monitor medium term effects.


Asunto(s)
Suelo , Incendios Forestales , Carbón Orgánico , Portugal , España
12.
Sci Total Environ ; 790: 148170, 2021 Oct 10.
Artículo en Inglés | MEDLINE | ID: mdl-34380273

RESUMEN

Understanding the global carbon (C) cycle is critical to accurately model feedbacks between climate and soil. Thus, many climate change studies focused on soil organic carbon (SOC) stock changes. Pyrogenic carbon (PyC) is one of the most stable fractions of soil organic matter (SOM). Accurate maps based on measured PyC contents are required to facilitate future soil management decisions and soil-climate feedback modelling. However, consistent measurements that cover large areas are rare. Therefore, this study aimed to map the PyC content and stock of the Iberian Peninsula, which covers contrasting climatic zones and has long-term data on wildfire occurrence. A partial least square (PLS) regression using the mid-infrared spectra (1800-400 cm-1) was applied to a dataset composed of 2961 soil samples from the Iberian component of the LUCAS 2009 database. The values of PyC for LUCAS points were modelled to obtain a map of topsoil PyC by a random forest (RF) approach using 36 auxiliary variables. The results were validated through comparison with documented historical wildfire activity and anthropogenic energy production. A strong relationship was found between these sources and the distribution of PyC. Our study estimates that the accumulated PyC in Iberian Peninsula soils comprises between 3.09 and 20.39% of total organic carbon (TOC) in the topsoil. Forests have higher PyC contents than grasslands, followed by agricultural soils. The incidence of recurrent wildfires also has a notable influence on PyC contents. This study shows the potential of estimating PyC with a single, rapid, low cost, chemometric method using new or archived soil spectra, and has the ability to improve soil-climate feedback modelling. It also offers a possible tool for measuring, reporting and verifying soil C stocks, which is likely to be important moving forward if soils are used as sinks for C sequestration.


Asunto(s)
Carbono , Incendios Forestales , Agricultura , Secuestro de Carbono , Cambio Climático , Suelo
13.
Sci Total Environ ; 777: 144579, 2021 Jul 10.
Artículo en Inglés | MEDLINE | ID: mdl-33677295

RESUMEN

The Guadalquivir Valley is one of three major O3 hotspots in Spain. An airborne and surface measurement campaign was carried out from July 9th to 11th, 2019 to quantify the local/regional O3 contributions using experimental approaches. Air quality and meteorology data from surface measurements, a microlight aircraft, a helium balloon, and remote sensing data (TROPOMI-NO2-ESA) were used to obtain the 3D distribution of O3 and various tracer pollutants. O3 accumulation over 2.5 days started with inputs from oceanic air masses transported inland by sea breezes, which drew O3 and its precursors from a local/regional origin to the northeastern end of the basin. The orographic-meteorological setting of the valley caused vertical recirculation of the air masses inside the valley that caused the accumulation by increasing regional background O3 concentration by 25-30 ppb. Furthermore, possible Mediterranean O3 contributions and additional vertical recirculation through the entrainment zone of the convective boundary layer also contributed. Using particulate matter finer than 2.5 µm (PM2.5), ultrafine particles (UFP), and black carbon (BC) as tracers of local sources, we calculated that local contributions increased regional O3 levels by 20 ppb inside specific pollution plumes transported by the breeze into the valley, and by 10 ppb during midday when flying over an area with abundant agricultural burning during the morning. Air masses that crossed the southern boundaries of the Betic system at mid-altitude (400-1850 m a.s.l.) on July 10th and 11th may have provided additional O3. Meanwhile, a decreasing trend at high altitudes (3000-5000 m a.s.l.) was observed, signifying that the impact of stratospheric O3 intrusion decreased during the campaign.

14.
Sci Total Environ ; 714: 136891, 2020 Apr 20.
Artículo en Inglés | MEDLINE | ID: mdl-32018998

RESUMEN

Hydrogen fluoride (HF) is one of the most toxic gaseous compounds in air, the primary anthropogenic source of which is industrial activity, specifically fertilizer and waste. HF concentrations in an urban area (Huelva, SW Spain) related to a nearby major phosphogypsum (PG) deposit were measured by passive sampling during summer and winter months from 2014 to 2017 and high-resolution sampling during 2017 and 2017-2018 using an HF analyser. An HF geochemical anomaly was found in the PG pond with average concentrations of up to 19.1 µg/m3, and concentrations of up to 1.6 µg/m3 were exhibited in the nearest urban area. The concentrations were associated with the HF emissions from the PG deposit. Emission factors were calculated by field and laboratory experiments, and the brines exhibited the highest emission factor (2.7 kg/ha day). Several impacts of HF (>0.1 µg/m3) in the city were recorded throughout the year, occurring at noon in the summer and during fog events in the winter. Consequently, the PG system should be restored to protect the population living in Huelva from the impacts of HF emission.

15.
Sci Total Environ ; 747: 141143, 2020 Dec 10.
Artículo en Inglés | MEDLINE | ID: mdl-32768769

RESUMEN

The lack of scientific information about the effects of wildfire on prehistoric structures and rock art, such as dolmens and petroglyphs, impedes the development of conservation guidelines. In this study, the impact of a recent wildfire (late 2017) on granite outcrops in the San Salvador de Coruxo archaeological site (Vigo, SW Galicia) was evaluated. Samples of the same type of granite were obtained from three sites characterised by different types of vegetation (natural scrub, native deciduous oak and non-native pine-eucalypt forest) in order to determine how the vegetation influences the fire-caused damage to the rock. Three subsamples were taken from each of the granite samples at depths of 1 cm-3 cm to study how fire affects the rock at depth. In all sites, the temperature reached at the granite surface was below 380 °C. No mineralogical changes due to fire exposure were detected, and no physical changes that could be attributed to the effect of the fire on the fissure system of the granite were identified. However, aesthetic colour changes due to the deposition of organic and charred matter, which even penetrated the fissures, were detected. The existence of lignin-derived compounds, lipids and carbohydrates in the samples from the oakwood site indicates greater resistance to fire effects in this type of vegetation than in the other two types. Although preliminary, these findings suggest that oakwoods could act as protective belts around archaeological sites by reducing the wildfire severity, because of their greater resistance to being burnt, and that they could buffer the damaging effects of fire in natural areas where parietal art is found.


Asunto(s)
Incendios , Pinus , Incendios Forestales , Bosques , Dióxido de Silicio
16.
IEEE Trans Nanobioscience ; 19(2): 183-191, 2020 04.
Artículo en Inglés | MEDLINE | ID: mdl-31905141

RESUMEN

La0.7 Sr0.3 MnO3 (LSMO) nanoparticles have been obtained via solution combustion synthesis (SCS) using urea and glycine as fuels. Also, La0.7 Sr0.27 Ca0.03 MnO3 (LSCMO) nanoparticles have been synthesized through solution combustion using urea as fuel. In this paper, the combustion process was carried out with a fuel to oxidant ratio giving fuel deficient conditions ( ). The thermal analysis (TGA) indicate that the organic residues from the urea-nitrates gel mixture are eliminated above 600 °C and the post-synthesis heat treatment yields the formation of the desired phase without impurities. The obtained phases were analyzed using X-ray diffraction. The infrared analysis confirms the purity of the samples obtained using urea. However, the sample obtained using glycine confirms the formation of SrCO3. The morphology was analyzed using a FE-SEM microscope, and it was found that the particles present a spherical shape with a mean size of around 45 nm in the selected samples. The samples' energy dispersive X-ray spectra show that the desired elements (La, Sr, Ca, Mn and O) are present in the nanoparticles. The measured zero field cooled (ZFC) and field cooled (FC) magnetizations were recorded from 4.5 to 380 K at 105 A/m to obtain their blocking and Curie temperatures. Moreover, the hysteresis loops measured at room temperature confirm the superparamagnetic behavior of the elaborated samples. According to the results obtained, these nanoparticles have interesting properties that make them candidates to explore not only for their potential in biomedical applications but also in refrigeration and magnetic storage devices.


Asunto(s)
Compuestos de Calcio , Lantano/química , Manganeso/química , Óxidos , Titanio , Urea/química , Compuestos de Calcio/síntesis química , Compuestos de Calcio/química , Técnicas de Química Sintética/métodos , Calor , Nanopartículas de Magnetita/química , Óxidos/síntesis química , Óxidos/química , Estroncio/química , Titanio/química
17.
Environ Res ; 109(6): 671-81, 2009 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-19501351

RESUMEN

In the South of Spain, major industrial estates (e.g. Huelva) exist alongside ecologically interesting zones (e.g. Doñana National Park). Between June 2005 and June 2006, PM10 and PM2.5 were measured, for total mass, organic carbon (OC) and elemental carbon (EC) chemical composition, at a station in an ecologically interesting area located near Doñana National Park and an urban background area with industrial influence. The mean OC concentration is higher in the urban background (3.5 microg m(-3)) than in the rural monitoring station (2.8 microg m(-3)) as a consequence of local emissions (e.g. traffic). A total of 82% of TC is OC in the rural station, while the urban background station reveals 70% and 73% of TC in the PM10 and PM2.5 mass, respectively. The study of air-mass origin and characterization of carbonaceous species in the course of simultaneous sampling in rural and urban background monitoring stations differentiated three long-range air-mass transports: a North-African dust outbreak, Atlantic Advection and Continental (N-NW) episodes, the origins of the first and last of which are more heavily influenced by the anthropogenic emissions from industrial estates located around the city of Huelva (Punta del Sebo and Nuevo Puerto). Higher values were measured for OC and EC in the study area during the North-African dust outbreak, similar to those obtained during the Continental episode (N-NW), which was clearly influenced by industrial emissions, followed by the Atlantic Advection episodes. The comparison of carbon species with air-mass origin can help to discriminate the origin and source of particulate matter, as well as to determine the urban impact on rural areas.


Asunto(s)
Contaminantes Atmosféricos/análisis , Carbono/análisis , Conservación de los Recursos Naturales , Monitoreo del Ambiente/métodos , Compuestos Orgánicos/análisis , Material Particulado/análisis , Industrias , Salud Rural , España , Salud Urbana , Viento
19.
Paediatr Perinat Epidemiol ; 22(3): 302-12, 2008 May.
Artículo en Inglés | MEDLINE | ID: mdl-18426526

RESUMEN

The uncertain accuracy of methods for detecting Helicobacter pylori infection in young children complicates research on this infection in early life. The aim of the present report was to describe the correspondence between positive serology and positive urea breath test (UBT) in children followed from age 0 to 24 months in the Pasitos Cohort Study, conducted along the US-Mexico border at El Paso and Juarez. Children were recruited before birth during 1998-2000 and examined at target ages of 6, 12, 18 and 24 months. H. pylori infection was detected using an enzyme immunoassay for serum immunoglobulin G antibodies and the (13)C-urea breath test corrected for age-dependent variation in CO(2) production. Of 472 children, 125 had one or more positive UBT results and 46 had one or more positive serology results. The prevalence of H. pylori infection at target ages of 6, 12, 18 and 24 months was 7%, 14%, 16% and 19%, respectively, by UBT and 8%, 2%, 3% and 3%, respectively, by serology. Few (<1%) of those tested on both tests were positive on both at any age. Among UBT-positive children, 6% were concurrently seropositive and 6% became seropositive later. Because UBT positivity cut points were selected to minimise false positives, these results suggest that H. pylori infection occurred frequently in this cohort, but rarely produced detectable antibodies. For clinical or epidemiological investigations, serology should not be used as the sole method for detecting H. pylori infection in children aged 2 years or less.


Asunto(s)
Pruebas Respiratorias , Infecciones por Helicobacter/diagnóstico , Helicobacter pylori/inmunología , Inmunoglobulina G/sangre , Adolescente , Factores de Edad , Radioisótopos de Carbono , Niño , Preescolar , Ensayo de Inmunoadsorción Enzimática , Métodos Epidemiológicos , Femenino , Infecciones por Helicobacter/epidemiología , Humanos , Lactante , Embarazo , Texas , Urea
20.
Actas Urol Esp ; 32(6): 659-61, 2008 Jun.
Artículo en Español | MEDLINE | ID: mdl-18655354

RESUMEN

We report a case of juvenile xanthogranuloma of the penis in a 30 year old patient with clinical suspicion of epidermoid cyst. Histology and ethiopathogenesis are reviewed, with special emphasis on the differential diagnosis with other similar lesions with worst prognosis.


Asunto(s)
Enfermedades del Pene/patología , Xantogranuloma Juvenil/patología , Adulto , Humanos , Masculino
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