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1.
Nature ; 575(7783): 459-463, 2019 11.
Artículo en Inglés | MEDLINE | ID: mdl-31748725

RESUMEN

Long-duration γ-ray bursts (GRBs) originate from ultra-relativistic jets launched from the collapsing cores of dying massive stars. They are characterized by an initial phase of bright and highly variable radiation in the kiloelectronvolt-to-megaelectronvolt band, which is probably produced within the jet and lasts from milliseconds to minutes, known as the prompt emission1,2. Subsequently, the interaction of the jet with the surrounding medium generates shock waves that are responsible for the afterglow emission, which lasts from days to months and occurs over a broad energy range from the radio to the gigaelectronvolt bands1-6. The afterglow emission is generally well explained as synchrotron radiation emitted by electrons accelerated by the external shock7-9. Recently, intense long-lasting emission between 0.2 and 1 teraelectronvolts was observed from GRB 190114C10,11. Here we report multi-frequency observations of GRB 190114C, and study the evolution in time of the GRB emission across 17 orders of magnitude in energy, from 5 × 10-6 to 1012 electronvolts. We find that the broadband spectral energy distribution is double-peaked, with the teraelectronvolt emission constituting a distinct spectral component with power comparable to the synchrotron component. This component is associated with the afterglow and is satisfactorily explained by inverse Compton up-scattering of synchrotron photons by high-energy electrons. We find that the conditions required to account for the observed teraelectronvolt component are typical for GRBs, supporting the possibility that inverse Compton emission is commonly produced in GRBs.

2.
Eur J Appl Physiol ; 123(10): 2203-2212, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37247005

RESUMEN

PURPOSE: The use of electrical stimulation to assess voluntary activation of muscle/s is a popular method employed in numerous exercise science and health research settings. This Delphi study aimed to collate expert opinion and provide recommendations for best practice when using electrical stimulation during maximal voluntary contractions. METHODS: A two-round Delphi study was undertaken with 30 experts who completed a 62-item questionnaire (Round 1) comprising of open- and closed-ended questions. Consensus was assumed if ≥ 70% of experts selected the same response; such questions were removed from the subsequent Round 2 questionnaire. Responses were also removed if they failed to meet a 15% threshold. Open-ended questions were analysed and converted into closed-ended questions for Round 2. It was assumed there was no clear consensus if a question failed to achieve a ≥ 70% response in Round 2. RESULTS: A total of 16 out of 62 (25.8%) items reached consensus. Experts agreed that electrical stimulation provides a valid assessment of voluntary activation in specific circumstances, such as during maximal contraction, and this stimulation can be applied at either the muscle or the nerve. Experts recommended using doublet stimuli, self-adhesive electrodes, a familiarisation session, real-time visual or verbal feedback during the contraction, a minimum current increase of + 20% to ensure supramaximal stimulation, and manually triggering stimuli. CONCLUSION: The results of this Delphi consensus study can help researchers make informed decisions when considering technical parameters when designing studies involving electrical stimulation for the assessment of voluntary activation.


Asunto(s)
Músculos , Humanos , Técnica Delphi , Consenso , Encuestas y Cuestionarios , Estimulación Eléctrica
3.
Exp Astron (Dordr) ; 52(3): 407-437, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-35153378

RESUMEN

The proposed THESEUS mission will vastly expand the capabilities to monitor the high-energy sky. It will specifically exploit large samples of gamma-ray bursts to probe the early universe back to the first generation of stars, and to advance multi-messenger astrophysics by detecting and localizing the counterparts of gravitational waves and cosmic neutrino sources. The combination and coordination of these activities with multi-wavelength, multi-messenger facilities expected to be operating in the 2030s will open new avenues of exploration in many areas of astrophysics, cosmology and fundamental physics, thus adding considerable strength to the overall scientific impact of THESEUS and these facilities. We discuss here a number of these powerful synergies and guest observer opportunities.

4.
Nature ; 506(7488): 364-6, 2014 Feb 20.
Artículo en Inglés | MEDLINE | ID: mdl-24553241

RESUMEN

Emerging infectious diseases (EIDs) pose a risk to human welfare, both directly and indirectly, by affecting managed livestock and wildlife that provide valuable resources and ecosystem services, such as the pollination of crops. Honeybees (Apis mellifera), the prevailing managed insect crop pollinator, suffer from a range of emerging and exotic high-impact pathogens, and population maintenance requires active management by beekeepers to control them. Wild pollinators such as bumblebees (Bombus spp.) are in global decline, one cause of which may be pathogen spillover from managed pollinators like honeybees or commercial colonies of bumblebees. Here we use a combination of infection experiments and landscape-scale field data to show that honeybee EIDs are indeed widespread infectious agents within the pollinator assemblage. The prevalence of deformed wing virus (DWV) and the exotic parasite Nosema ceranae in honeybees and bumblebees is linked; as honeybees have higher DWV prevalence, and sympatric bumblebees and honeybees are infected by the same DWV strains, Apis is the likely source of at least one major EID in wild pollinators. Lessons learned from vertebrates highlight the need for increased pathogen control in managed bee species to maintain wild pollinators, as declines in native pollinators may be caused by interspecies pathogen transmission originating from managed pollinators.


Asunto(s)
Abejas/parasitología , Abejas/virología , Parásitos/patogenicidad , Polinización , Virus ARN/patogenicidad , Animales , Apicultura/métodos , Abejas/clasificación , Abejas/fisiología , Datos de Secuencia Molecular , Parásitos/genética , Parásitos/aislamiento & purificación , Polinización/fisiología , Virus ARN/genética , Virus ARN/aislamiento & purificación , Riesgo , Reino Unido
5.
J Theor Biol ; 436: 39-50, 2018 01 07.
Artículo en Inglés | MEDLINE | ID: mdl-28970093

RESUMEN

Immunotherapies exploit the immune system to target and kill cancer cells, while sparing healthy tissue. Antibody therapies, an important class of immunotherapies, involve the binding to specific antigens on the surface of the tumour cells of antibodies that activate natural killer (NK) cells to kill the tumour cells. Preclinical assessment of molecules that may cause antibody-dependent cellular cytotoxicity (ADCC) involves co-culturing cancer cells, NK cells and antibody in vitro for several hours and measuring subsequent levels of tumour cell lysis. Here we develop a mathematical model of such an in vitro ADCC assay, formulated as a system of time-dependent ordinary differential equations and in which NK cells kill cancer cells at a rate which depends on the amount of antibody bound to each cancer cell. Numerical simulations generated using experimentally-based parameter estimates reveal that the system evolves on two timescales: a fast timescale on which antibodies bind to receptors on the surface of the tumour cells, and NK cells form complexes with the cancer cells, and a longer time-scale on which the NK cells kill the cancer cells. We construct approximate model solutions on each timescale, and show that they are in good agreement with numerical simulations of the full system. Our results show how the processes involved in ADCC change as the initial concentration of antibody and NK-cancer cell ratio are varied. We use these results to explain what information about the tumour cell kill rate can be extracted from the cytotoxicity assays.


Asunto(s)
Citotoxicidad Celular Dependiente de Anticuerpos , Modelos Inmunológicos , Línea Celular Tumoral , Humanos , Análisis Numérico Asistido por Computador
6.
J Neurooncol ; 136(3): 613-622, 2018 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-29168082

RESUMEN

Brain tumor patients treated with radiotherapy (RT) often develop cognitive dysfunction, and recent studies suggest that the APOE ε-4 allele may influence cognitive outcome. The ε-4 allele is known to promote beta (ß) amyloid deposition in the cortex, and preliminary evidence suggests that RT may be associated with this process. However, it is unknown whether ß-amyloid accumulation contributes to treatment neurotoxicity. In this pilot study, we assessed neuropsychological functions and ß-amyloid retention using 18F-florbetaben (FBB) PET in a subset of brain tumor patients who participated in our study of APOE polymorphisms and cognitive functions. Twenty glioma patients treated with conformal RT ± chemotherapy participated in the study: 6 were APOE ε-4 carriers and 14 were non-ε-4 carriers. Patients completed a neuropsychological re-evaluation (mean time interval = 5 years, SD = 0.83) and brain MRI and FBB PET scans. Wilcoxon signed-rank test comparisons between prior and current neuropsychological assessments showed a significant decline in attention (Brief Test of Attention, p = 0.018), and a near significant decline in verbal learning (Hopkins Verbal learning Test-Learning, p = 0.07). Comparisons by APOE status showed significant differences over time in attention/working memory (WAIS-III digits forward, p = 0.028 and digits backward, p = 0.032), with a decline among APOE ε-4 carriers. There were no significant differences in any of the FBB PET analyses between APOE ε-4 carriers and non-ε-4 carriers. The findings suggest that glioma patients may experience worsening in attention and executive functions several years after treatment, and that the APOE ε-4 allele may modulate cognitive decline, but independent of increased ß-amyloid deposition.


Asunto(s)
Amiloide/metabolismo , Apolipoproteína E4/genética , Neoplasias Encefálicas/diagnóstico por imagen , Neoplasias Encefálicas/psicología , Glioma/diagnóstico por imagen , Glioma/psicología , Adulto , Anciano , Compuestos de Anilina , Encéfalo/diagnóstico por imagen , Encéfalo/metabolismo , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/metabolismo , Quimioradioterapia , Cognición , Trastornos del Conocimiento/diagnóstico por imagen , Trastornos del Conocimiento/etiología , Trastornos del Conocimiento/genética , Trastornos del Conocimiento/metabolismo , Estudios de Cohortes , Femenino , Glioma/genética , Glioma/metabolismo , Heterocigoto , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Pruebas Neuropsicológicas , Proyectos Piloto , Tomografía de Emisión de Positrones , Radiofármacos , Radioterapia Conformacional , Estilbenos
7.
Nature ; 476(7361): 421-4, 2011 Aug 24.
Artículo en Inglés | MEDLINE | ID: mdl-21866154

RESUMEN

Supermassive black holes have powerful gravitational fields with strong gradients that can destroy stars that get too close, producing a bright flare in ultraviolet and X-ray spectral regions from stellar debris that forms an accretion disk around the black hole. The aftermath of this process may have been seen several times over the past two decades in the form of sparsely sampled, slowly fading emission from distant galaxies, but the onset of the stellar disruption event has not hitherto been observed. Here we report observations of a bright X-ray flare from the extragalactic transient Swift J164449.3+573451. This source increased in brightness in the X-ray band by a factor of at least 10,000 since 1990 and by a factor of at least 100 since early 2010. We conclude that we have captured the onset of relativistic jet activity from a supermassive black hole. A companion paper comes to similar conclusions on the basis of radio observations. This event is probably due to the tidal disruption of a star falling into a supermassive black hole, but the detailed behaviour differs from current theoretical models of such events.

8.
J Theor Biol ; 394: 149-159, 2016 Apr 07.
Artículo en Inglés | MEDLINE | ID: mdl-26796221

RESUMEN

The hydrostatic pressure stimulation of an appropriately cell-seeded porous scaffold within a bioreactor is a promising method for engineering bone tissue external to the body. We propose a mathematical model, and employ a suite of candidate constitutive laws, to qualitatively describe the effect of applied hydrostatic pressure on the quantity of minerals deposited in such an experimental setup. By comparing data from numerical simulations with experimental observations under a number of stimulation protocols, we suggest that the response of bone cells to an applied pressure requires consideration of two components; (i) a component describing the cell memory of the applied stimulation, and (ii) a recovery component, capturing the time cells require to recover from high rates of mineralisation.


Asunto(s)
Desarrollo Óseo , Presión Hidrostática , Modelos Biológicos , Ingeniería de Tejidos/métodos , Calcificación Fisiológica , Simulación por Computador , Minerales/metabolismo
9.
J Intellect Disabil Res ; 60(10): 1031-42, 2016 10.
Artículo en Inglés | MEDLINE | ID: mdl-27545817

RESUMEN

BACKGROUND: Specific phobia (SP) is the most common anxiety disorder among children with Williams syndrome (WS); prevalence rates derived from Diagnostic and Statistical Manual of Mental Disorders-based diagnostic interviews range from 37% to 56%. We evaluated the effects of gender, age, intellectual abilities and/or behaviour regulation difficulties on the likelihood that a child with WS would be diagnosed with SP. METHODS: A total of 194 6-17 year-olds with WS were evaluated. To best characterise the relations between the predictors and the probability of a SP diagnosis, we explored not only possible linear effects but also curvilinear effects. RESULTS: No gender differences were detected. As age increased, the likelihood of receiving a SP diagnosis decreased. As IQ increased, the probability of receiving a SP diagnosis also decreased. Behaviour regulation difficulties were the strongest predictor of a positive diagnosis. A quadratic relation was detected: The probability of receiving a SP diagnosis gradually rose as behaviour regulation difficulties increased. However, once behaviour regulation difficulties approached the clinical range, the probability of receiving a SP diagnosis asymptoted at a high level. CONCLUSION: Children with behaviour regulation difficulties in or just below the clinical range were at the greatest risk of developing SP. These findings highlight the value of large samples and the importance of evaluating for nonlinear effects to provide accurate model specification when characterising relations among a dependent variable and possible predictors.


Asunto(s)
Trastornos Fóbicos/epidemiología , Autocontrol , Síndrome de Williams/epidemiología , Síndrome de Williams/fisiopatología , Adolescente , Niño , Comorbilidad , Femenino , Humanos , Masculino
10.
Ecol Modell ; 340: 126-133, 2016 Nov 24.
Artículo en Inglés | MEDLINE | ID: mdl-27890965

RESUMEN

Social bees are central place foragers collecting floral resources from the surrounding landscape, but little is known about the probability of a scouting bee finding a particular flower patch. We therefore developed a software tool, BEESCOUT, to theoretically examine how bees might explore a landscape and distribute their scouting activities over time and space. An image file can be imported, which is interpreted by the model as a "forage map" with certain colours representing certain crops or habitat types as specified by the user. BEESCOUT calculates the size and location of these potential food sources in that landscape relative to a bee colony. An individual-based model then determines the detection probabilities of the food patches by bees, based on parameter values gathered from the flight patterns of radar-tracked honeybees and bumblebees. Various "search modes" describe hypothetical search strategies for the long-range exploration of scouting bees. The resulting detection probabilities of forage patches can be used as input for the recently developed honeybee model BEEHAVE, to explore realistic scenarios of colony growth and death in response to different stressors. In example simulations, we find that detection probabilities for food sources close to the colony fit empirical data reasonably well. However, for food sources further away no empirical data are available to validate model output. The simulated detection probabilities depend largely on the bees' search mode, and whether they exchange information about food source locations. Nevertheless, we show that landscape structure and connectivity of food sources can have a strong impact on the results. We believe that BEESCOUT is a valuable tool to better understand how landscape configurations and searching behaviour of bees affect detection probabilities of food sources. It can also guide the collection of relevant data and the design of experiments to close knowledge gaps, and provides a useful extension to the BEEHAVE honeybee model, enabling future users to explore how landscape structure and food availability affect the foraging decisions and patch visitation rates of the bees and, in consequence, to predict colony development and survival.

11.
Poult Sci ; 95(4): 749-59, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-26908890

RESUMEN

One experiment was conducted to evaluate the effects of two incubation temperature profiles (TEM) and two trace mineral (TM) sources with their inclusion levels on performance and footpad skin development of Ross 708 chickens. A total of 1,000 eggs from 29-wk-old breeders were incubated following two TEM profiles: a standard (S) eggshell temperature (37.8±0.2°C) for 21 d of incubation and an early-low late-high (LH) TEM. The second profile had low (37.2±0.2°C) temperature for the first 3 d, and S until the last 3 d when eggshell temperature was 39.2±0.2°C. At hatch, 15 male and 15 female chicks from each TEM were selected, and footpads sampled. Additionally, 168 males per TEM were placed in 24 battery cages with 7 chickens each. The 48 cages were assigned to two TM dietary treatments: one with inorganic (ITM) sources of Zn (120 ppm), Cu (10 ppm), and Mn (120 ppm) and the other with chelated (CTM) mineral sources using lower inclusion levels of Zn (32 ppm), Cu (8 ppm), and Mn (32 ppm). At 7 and 21 d, BW gain and feed conversion ratio (FCR) were obtained and chicks sampled for footpads. Histological analysis assessed thickness and area ofstratus corneum(SC), epidermis, and dermis. Data were analyzed as a completely randomized block design in a 2×2 factorial arrangement of treatments with TEM and sex as main factors for hatch data and TEM and TM diets for 7 and 21 d data. The LH chicks were heavier than S chicks at hatch, but had more residual yolk. However, S TEM male chickens were heavier at 7 and 21 d. The S TEM had better FCR than LH TEM.Papillaedermis parameters at hatch were higher in the S TEM. At 7 d, SC height and area were increased by the S TEM. At 21 d CTM increased dermis height and area. In conclusion, TEM affected footpad skin development and broiler performance. Replacing ITM with reduced levels of CTM increased dermis development without affecting live performance or other skin layers.


Asunto(s)
Pollos/fisiología , Pie/fisiología , Temperatura , Oligoelementos/metabolismo , Alimentación Animal/análisis , Crianza de Animales Domésticos , Animales , Pollos/crecimiento & desarrollo , Colágeno/análisis , Dermis/crecimiento & desarrollo , Dieta/veterinaria , Suplementos Dietéticos/análisis , Epidermis/crecimiento & desarrollo , Femenino , Pie/crecimiento & desarrollo , Masculino , Distribución Aleatoria , Reproducción
12.
J Dairy Sci ; 98(3): 1502-16, 2015 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-25597968

RESUMEN

Cheese can be modeled as a filled gel whereby milkfat globules are dispersed in a casein gel network. We determined the filler effects using Sephadex beads (GE Healthcare Life Sciences, Pittsburgh, PA) as a model filler particle. Ideally, such a model could be used to test novel filler particles to replace milkfat in low-fat cheese. Low-filler (6% particles), reduced-filler (16%), and full-filler (33%) cheeses were produced using either Sephadex beads of varying sizes (20 to 150 µm diameter) or milkfat. Small- and large-strain rheological tests were run on each treatment at 8, 12, and 18 wk after cheese manufacturing. Differences in rheological properties were caused primarily by the main effects of filler volume and type (milkfat vs. Sephadex), whereas filler size had no obvious effect. All treatments showed a decrease in deformability and an increase in firmness as filler volume increased above 25%, although the beads exhibited a greater reinforcing effect and greater energy recovery than milkfat.


Asunto(s)
Queso/análisis , Dextranos/química , Manipulación de Alimentos/métodos , Animales , Caseínas/química , Reología
13.
Br Poult Sci ; 56(3): 345-60, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25811235

RESUMEN

1. The aim of this study was to evaluate the effects of diet type, maternal feeding programme at 29 weeks of age and breeder feeder space change at photostimulation on broiler progeny performance and leg health at 6 weeks of age. 2. Fast-feathering Cobb 500 broiler breeders were fed on either maize- or wheat-based diets that had been formulated to have similar nutrient composition during growing and layer phases. Two feeding programmes, fast or flow, were used from 14 to 29 weeks of age. At 22 weeks, 69 females from each pen were placed in a layer house where feeder space was either similar to that in rearing (6.3 to 6.5 cm/female) or was increased from 6.3 to 8.4 cm/female. Eggs produced at 32 and 44 weeks of age were collected and incubated for two broiler experiments. A total of 16 male and 16 female one-d-old chicks were placed in floor pens in two experiments, respectively, with 6 and 4 replicate pens. Broiler gait scores and leg problem prevalence were evaluated at 6 weeks of age. 3. Data were analysed as a 2 × 2 × 2 factorial design with diet type, feeding programme and feeder space change as main factors. 4. The wheat diet increased the probability of observing crooked toes in broiler progeny compared to the use of maize, but only when breeders were fed according to the fast feeding programme and given similar feeder space as during rearing. 5. Breeders given more feeder space in the laying period produced progeny with more locomotion problems compared with those provided similar feeder space, but only when maize was used and the slow feeding programme was applied to the breeders. 6. The maternal feeding programme interacted with other factors to influence progeny leg health, but it did not solely influence walking ability or leg problems of progeny. 7. In conclusion, an increased probability of observing walking impairment of broiler progeny was detected when breeders were given greater feeder space at photostimulation rather than no change and fed according to the slow feeding programme using maize diets in breeders and progeny.


Asunto(s)
Crianza de Animales Domésticos/métodos , Pollos , Extremidad Inferior/patología , Enfermedades de las Aves de Corral/etiología , Triticum/química , Zea mays/química , Alimentación Animal/análisis , Fenómenos Fisiológicos Nutricionales de los Animales/efectos de los fármacos , Animales , Pollos/crecimiento & desarrollo , Pollos/metabolismo , Dieta/veterinaria , Femenino , Masculino , Estimulación Luminosa , Distribución Aleatoria
14.
J Math Biol ; 67(5): 1199-225, 2013 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-22986893

RESUMEN

In vitro tissue engineering is emerging as a potential tool to meet the high demand for replacement tissue, caused by the increased incidence of tissue degeneration and damage. A key challenge in this field is ensuring that the mechanical properties of the engineered tissue are appropriate for the in vivo environment. Achieving this goal will require detailed understanding of the interplay between cell proliferation, extracellular matrix (ECM) deposition and scaffold degradation. In this paper, we use a mathematical model (based upon a multiphase continuum framework) to investigate the interplay between tissue growth and scaffold degradation during tissue construct evolution in vitro. Our model accommodates a cell population and culture medium, modelled as viscous fluids, together with a porous scaffold and ECM deposited by the cells, represented as rigid porous materials. We focus on tissue growth within a perfusion bioreactor system, and investigate how the predicted tissue composition is altered under the influence of (1) differential interactions between cells and the supporting scaffold and their associated ECM, (2) scaffold degradation, and (3) mechanotransduction-regulated cell proliferation and ECM deposition. Numerical simulation of the model equations reveals that scaffold heterogeneity typical of that obtained from [Formula: see text]CT scans of tissue engineering scaffolds can lead to significant variation in the flow-induced mechanical stimuli experienced by cells seeded in the scaffold. This leads to strong heterogeneity in the deposition of ECM. Furthermore, preferential adherence of cells to the ECM in favour of the artificial scaffold appears to have no significant influence on the eventual construct composition; adherence of cells to these supporting structures does, however, lead to cell and ECM distributions which mimic and exaggerate the heterogeneity of the underlying scaffold. Such phenomena have important ramifications for the mechanical integrity of engineered tissue constructs and their suitability for implantation in vivo.


Asunto(s)
Proliferación Celular , Matriz Extracelular/fisiología , Mecanotransducción Celular/fisiología , Modelos Biológicos , Ingeniería de Tejidos/métodos , Reactores Biológicos , Simulación por Computador , Humanos
15.
J Vet Pharmacol Ther ; 36(5): 471-7, 2013 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-23256899

RESUMEN

Intravenous benzodiazepines are utilized as first-line drugs to treat prolonged epileptic seizures in dogs and alternative routes of administration are required when venous access is limited. This study compared the pharmacokinetics of midazolam after intravenous (IV), intramuscular (IM), and rectal (PR) administration. Six healthy dogs were administered 0.2 mg/kg midazolam IV, IM, or PR in a randomized, 3-way crossover design with a 3-day washout between study periods. Blood samples were collected at baseline and at predetermined intervals until 480 min after administration. Plasma midazolam concentrations were measured by high-pressure liquid chromatography with UV detection. Rectal administration resulted in erratic systemic availability with undetectable to low plasma concentrations. Arithmetic mean values ± SD for midazolam peak plasma concentrations were 0.86 ± 0.36 µg/mL (C0) and 0.20 ± 0.06 µg/mL (Cmax), following IV and IM administration, respectively. Time to peak concentration (Tmax ) after IM administration was 7.8 ± 2.4 min with a bioavailability of 50 ± 16%. Findings suggest that IM midazolam might be useful in treating seizures in dogs when venous access is unavailable, but higher doses may be needed to account for intermediate bioavailability. Rectal administration is likely of limited efficacy for treating seizures in dogs.


Asunto(s)
Anticonvulsivantes/farmacocinética , Midazolam/farmacocinética , Administración Rectal , Animales , Anticonvulsivantes/administración & dosificación , Anticonvulsivantes/sangre , Cromatografía Líquida de Alta Presión , Perros , Femenino , Inyecciones Intramusculares/veterinaria , Inyecciones Intravenosas/veterinaria , Masculino , Midazolam/administración & dosificación , Midazolam/sangre
16.
AJNR Am J Neuroradiol ; 44(7): 783-791, 2023 07.
Artículo en Inglés | MEDLINE | ID: mdl-37290818

RESUMEN

BACKGROUND AND PURPOSE: While contrast-enhanced MR imaging is the criterion standard in meningioma diagnosis and treatment response assessment, gallium 68Ga-DOTATATE PET/MR imaging has increasingly demonstrated utility in meningioma diagnosis and management. Integrating 68Ga-DOTATATE PET/MR imaging in postsurgical radiation planning reduces the planning target volume and organ-at-risk dose. However, 68Ga-DOTATATE PET/MR imaging is not widely implemented in clinical practice due to higher perceived costs. Our study analyzes the cost-effectiveness of 68Ga-DOTATATE PET/MR imaging for postresection radiation therapy planning in patients with intermediate-risk meningioma. MATERIALS AND METHODS: We developed a decision-analytical model based on both recommended guidelines on meningioma management and our institutional experience. Markov models were implemented to estimate quality-adjusted life-years (QALY). Cost-effectiveness analyses with willingness-to-pay thresholds of $50,000/QALY and $100,000/QALY were performed from a societal perspective. Sensitivity analyses were conducted to validate the results. Model input values were based on published literature. RESULTS: The cost-effectiveness results demonstrated that 68Ga-DOTATATE PET/MR imaging yields higher QALY (5.47 versus 5.05) at a higher cost ($404,260 versus $395,535) compared with MR imaging alone. The incremental cost-effectiveness ratio analysis determined that 68Ga-DOTATATE PET/MR imaging is cost-effective at a willingness to pay of $50,000/QALY and $100,000/QALY. Furthermore, sensitivity analyses showed that 68Ga-DOTATATE PET/MR imaging is cost-effective at $50,000/QALY ($100,000/QALY) for specificity and sensitivity values above 76% (58%) and 53% (44%), respectively. CONCLUSIONS: 68Ga-DOTATATE PET/MR imaging as an adjunct imaging technique is cost-effective in postoperative treatment planning in patients with meningiomas. Most important, the model results show that the sensitivity and specificity cost-effective thresholds of 68Ga-DOTATATE PET/MR imaging could be attained in clinical practice.


Asunto(s)
Neoplasias Meníngeas , Meningioma , Compuestos Organometálicos , Humanos , Meningioma/diagnóstico por imagen , Meningioma/radioterapia , Radioisótopos de Galio , Análisis de Costo-Efectividad , Tomografía de Emisión de Positrones/métodos , Imagen por Resonancia Magnética/métodos , Neoplasias Meníngeas/diagnóstico por imagen , Neoplasias Meníngeas/radioterapia
17.
Nature ; 440(7081): 164, 2006 Mar 09.
Artículo en Inglés | MEDLINE | ID: mdl-16525462

RESUMEN

Long gamma-ray bursts (GRBs) are bright flashes of high-energy photons that can last for tens of minutes; they are generally associated with galaxies that have a high rate of star formation and probably arise from the collapsing cores of massive stars, which produce highly relativistic jets (collapsar model). Here we describe gamma- and X-ray observations of the most distant GRB ever observed (GRB 050904): its redshift (z) of 6.29 means that this explosion happened 12.8 billion years ago, corresponding to a time when the Universe was just 890 million years old, close to the reionization era. This means that not only did stars form in this short period of time after the Big Bang, but also that enough time had elapsed for them to evolve and collapse into black holes.

18.
Nature ; 442(7106): 1008-10, 2006 Aug 31.
Artículo en Inglés | MEDLINE | ID: mdl-16943830

RESUMEN

Although the link between long gamma-ray bursts (GRBs) and supernovae has been established, hitherto there have been no observations of the beginning of a supernova explosion and its intimate link to a GRB. In particular, we do not know how the jet that defines a gamma-ray burst emerges from the star's surface, nor how a GRB progenitor explodes. Here we report observations of the relatively nearby GRB 060218 (ref. 5) and its connection to supernova SN 2006aj (ref. 6). In addition to the classical non-thermal emission, GRB 060218 shows a thermal component in its X-ray spectrum, which cools and shifts into the optical/ultraviolet band as time passes. We interpret these features as arising from the break-out of a shock wave driven by a mildly relativistic shell into the dense wind surrounding the progenitor. We have caught a supernova in the act of exploding, directly observing the shock break-out, which indicates that the GRB progenitor was a Wolf-Rayet star.

19.
Lett Appl Microbiol ; 54(3): 187-94, 2012 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-22150460

RESUMEN

AIMS: To investigate the impact of acetaldehyde- and pyruvic acid-bound sulphur dioxide on wine lactic acid bacteria (LAB). METHODS AND RESULTS: Growth studies were performed where Oenococcus oeni, Pediococcus parvulus, Ped. damnosus and Lactobacillus hilgardii were inoculated into media containing various concentrations of acetaldehyde or pyruvic acid and an equimolar concentration of SO(2) at pH 3.50 and 3.70. Low concentrations of acetaldehyde- and pyruvic acid-bound SO(2) were inhibitory to the growth of all bacteria although acetaldehyde-bound SO(2) was generally more inhibitory than pyruvic acid-bound SO(2). Inhibition was greater at pH 3.50 than 3.70, and Lact. hilgardii was the most sensitive to acetaldehyde-bound SO(2), while O. oeni was the most sensitive to pyruvic acid-bound SO(2). Degradation of SO(2)-bound acetaldehyde was observed for all LAB, and aside from O. oeni, there was also complete degradation of SO(2)-bound pyruvic acid at both pH values. O. oeni only degraded pyruvic acid at pH 3.70. Degradation of SO(2)-bound acetaldehyde or pyruvic acid did not correlate with bacterial growth as inhibition was always observed in media containing bound SO(2). CONCLUSIONS: Acetaldehyde- and pyruvic acid-bound SO(2) were inhibitory to wine LAB growth at concentrations as low as 5 mg l(-1). Despite this inhibition, all wine LAB degraded SO(2)-bound acetaldehyde and pyruvic acid suggesting that bound SO(2) may have a bacteriostatic rather than bacteriocidal action. SIGNIFICANCE AND IMPACT OF THE STUDY: Sulphur dioxide bound to acetaldehyde or pyruvic acid is inhibitory to growth of wine LAB and must be considered when conducting the malolactic fermentation or controlling the growth of spoilage bacteria such as Pediococcus and Lactobacillus.


Asunto(s)
Acetaldehído/farmacología , Lactobacillaceae/efectos de los fármacos , Ácido Pirúvico/farmacología , Dióxido de Azufre/farmacología , Vino/microbiología , Medios de Cultivo/química , Fermentación , Concentración de Iones de Hidrógeno , Ácido Láctico/metabolismo , Lactobacillaceae/crecimiento & desarrollo
20.
Euro Surveill ; 17(48)2012 Nov 29.
Artículo en Inglés | MEDLINE | ID: mdl-23218389

RESUMEN

A patient with fever, and haemorrhagic symptoms was admitted to a hospital in Glasgow on 2 October 2012. Since he had returned from Afghanistan, serum samples were sent for diagnosis at the Rare and Imported Pathogens Laboratory, where a real-time reverse transcriptase-PCR diagnosis of Crimean ­ Congo haemorrhagic fever was made within 3 hrs after receipt of the sample. Hereafter the patient was transferred to a high-security infectious diseases unit in London but died on 6 October.


Asunto(s)
Virus de la Fiebre Hemorrágica de Crimea-Congo , Fiebre Hemorrágica de Crimea/mortalidad , Viaje , Afganistán/epidemiología , Biomarcadores , Brotes de Enfermedades , Fiebre Hemorrágica de Crimea/diagnóstico , Humanos , Inmunoglobulina G/biosíntesis , Inmunoglobulina M/biosíntesis , Londres/epidemiología , Masculino , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodos , Emiratos Árabes Unidos/epidemiología
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