3,591 research outputs found
Frequency of visualization of celiac ganglia by endoscopic ultrasound and its potential in assessing neural invasion in patients with pancreatic lesions
AbstractBackgroundCeliac ganglia (CG) can be seen by endoscopic ultrasound; they play an important role in pain management and are a potential site for extrapancreatic tumor neural invasion.AimsTo evaluate the frequency of CG visualization during endoscopic ultrasound examination and to evaluate the feasibility of this technique to identify extrapancreatic tumor neural invasion in patients with pancreatic lesions.MethodsWe retrospectively reviewed all endoscopic ultrasound studies performed between November 2007 and June 2010. Images of the celiac region were presented to an endosonographer, who reported the presence or absence of CG.ResultsWe included 31 cases. CG were identified in 14 (45%) cases. Average size was 10mm (range 4-25mm) by±1mm (range 1-7mm). In 2 cases, fine needle aspiration biopsy was performed and reported nerve cell bodies; in one case malignant cells were seen.ConclusionsCG were identified in 45% of the cases. Fine needle aspiration biopsy can detect unanticipated extrapancreatic tumor neural invasion in pancreatic malignancies
Synergistic antimycobacterial activities of sesquiterpene lactones from Laurus spp
The aim of this study was to determine the antimycobacterial potential of laurel oil, its fractions and its two sesquiterpene lactones against several mycobacterial strains and clinical isolates, and to establish the possibility of occurrence of some synergistic effects between those lactones using a modification of the fluorometric Alamar Blue microassay (FMABA).info:eu-repo/semantics/publishedVersio
The Inverse Scattering Method, Lie-Backlund Transformations and Solitons for Low-energy Effective Field Equations of 5D String Theory
In the framework of the 5D low-energy effective field theory of the heterotic
string with no vector fields excited, we combine two non-linear methods in
order to construct a solitonic field configuration. We first apply the inverse
scattering method on a trivial vacuum solution and obtain an stationary
axisymmetric two-soliton configuration consisting of a massless gravitational
field coupled to a non-trivial chargeless dilaton and to an axion field endowed
with charge. The implementation of this method was done following a scheme
previously proposed by Yurova. We also show that within this scheme, is not
possible to get massive gravitational solitons at all. We then apply a
non-linear Lie-Backlund matrix transformation of Ehlers type on this massless
solution and get a massive rotating axisymmetric gravitational soliton coupled
to axion and dilaton fields endowed with charges. We study as well some
physical properties of the constructed massless and massive solitons and
discuss on the effect of the generalized solution generating technique on the
seed solution and its further generalizations.Comment: 17 pages in latex, changed title, improved text, added reference
The detection of airborne transmission of tuberculosis from HIV-infected patients, using an in vivo air sampling model
Background. Nosocomial transmission of tuberculosis remains an important public health problem. We created an in vivo air sampling model to study airborne transmission of tuberculosis from patients coinfected with human immunodeficiency virus (HIV) and to evaluate environmental control measures.
Methods. An animal facility was built above a mechanically ventilated HIV‐tuberculosis ward in Lima, Peru. A mean of 92 guinea pigs were continuously exposed to all ward exhaust air for 16 months. Animals had tuberculin skin tests performed at monthly intervals, and those with positive reactions were removed for autopsy and culture for tuberculosis.
Results. Over 505 consecutive days, there were 118 ward admissions by 97 patients with pulmonary tuberculosis, with a median duration of hospitalization of 11 days. All patients were infected with HIV and constituted a heterogeneous group with both new and existing diagnoses of tuberculosis. There was a wide variation in monthly rates of guinea pigs developing positive tuberculin test results (0%–53%). Of 292 animals exposed to ward air, 159 developed positive tuberculin skin test results, of which 129 had laboratory confirmation of tuberculosis. The HIV‐positive patients with pulmonary tuberculosis produced a mean of 8.2 infectious quanta per hour, compared with 1.25 for HIV‐negative patients with tuberculosis in similar studies from the 1950s. The mean monthly patient infectiousness varied greatly, from production of 0–44 infectious quanta per hour, as did the theoretical risk for a health care worker to acquire tuberculosis by breathing ward air.
Conclusions. HIV‐positive patients with tuberculosis varied greatly in their infectiousness, and some were highly infectious. Use of environmental control strategies for nosocomial tuberculosis is therefore a priority, especially in areas with a high prevalence of both tuberculosis and HIV infection
InSAR-Based Mapping to Support Decision-Making after an Earthquake
It has long been recognized that earthquakes change the stress in the upper crust around
the fault rupture and can influence the behaviour of neighbouring faults and volcanoes. Rapid
estimates of these stress changes can provide the authorities managing the post-disaster situation
with valuable data to identify and monitor potential threads and to update the estimates of seismic
and volcanic hazard in a region. Here we propose a methodology to evaluate the potential
influence of an earthquake on nearby faults and volcanoes and create easy-to-understand maps
for decision-making support after large earthquakes. We apply this methodology to the Mw 7.8,
2016 Ecuador earthquake. Using Sentinel-1 Interferometric Synthetic Aperture Radar (InSAR) and
continuous GPS data, we measure the coseismic ground deformation and estimate the distribution
of slip over the fault rupture. We also build an alternative source model using the Global Centroid
Moment Tensor (CMT) solution. Then we use these models to evaluate changes of static stress
on the surrounding faults and volcanoes and produce maps of potentially activated faults and
volcanoes. We found, in general, good agreement between our maps and the seismic and volcanic
events that occurred after the Pedernales earthquake. We discuss the potential and limitations of
the methodology.This work is supported by the European Commission, Directorate-General Humanitarian
Aid and Civil Protection (ECHO) under the SAFETY (Sentinel for Geohazards regional monitoring and forecasting)
project (ECHO/SUB/2015/718679/Prev02) and by the Spanish Ministry of Economy and Competitiveness under
INTERGEOSIMA (CGL2013-47412) and ACTIVESTEP (CGL2017-83931-C3), QUAKESTEP (1-P) + 3GEO(2-P)
+ GEOACTIVA (3-P) projects
Localization of gravity on a de Sitter thick braneworld without scalar fields
In this work we present a simple thick braneworld model that is generated by
an intriguing interplay between a 5D cosmological constant with a de Sitter
metric induced in the 3-brane without the inclusion of scalar fields. We show
that 4D gravity is localized on this brane, provide analytic expressions for
the massive Kaluza-Klein (KK) fluctuation modes and also show that the spectrum
of metric excitations displays a mass gap. We finally present the corrections
to Newton's law due to these massive modes. This model has no naked
singularities along the fifth dimension despite the existence of a mass gap in
the graviton spectrum as it happens in thick branes with 4D Poincare symmetry,
providing a simple model with very good features: the curvature is completely
smooth along the fifth dimension, it localizes 4D gravity and the spectrum of
gravity fluctuations presents a mass gap, a fact that rules out the existence
of phenomenologically dangerous ultralight KK excitations in the model. We
finally present our solution as a limit of scalar thick branes.Comment: 11 pages in latex, no figures, title and abstract changed, a new
section and some references adde
Long-term variability and trends in meteorological droughts in Western Europe (1851-2018)
We analyzed long-term variability and trends in meteorological droughts across Western Europe using the Standardized Precipitation Index (SPI). Precipitation data from 199 stations spanning the period 1851-2018 were employed, following homogenisation, to derive SPI-3 and SPI-12 series for each station, together with indices on drought duration and severity. Results reveal a general absence of statistically significant long-term trends in the study domain, with the exception of significant trends at some stations, generally covering short periods. The largest decreasing trends in SPI-3 (i.e. increasing drought conditions) were found for summer in the British and Irish Isles. In general, drought episodes experienced in the last two or three decades have precedents during the last 170 years, emphasising the importance of long records for assessing change. The main characteristic of drought variability in Western Europe is its strong spatial diversity, with regions exhibiting a homogeneous temporal evolution. Notably, the temporal variability of drought in Western Europe is more dominant than long-term trends. This suggests that long-term drought trends cannot be confirmed in Western Europe using precipitation records alone. This study provides a long-term regional assessment of drought variability in Western Europe, which can contribute to better understanding of regional climate change during the past two centuries.This work was supported by the research projects PCIN-2015-220 and CGL2017-
82216-R financed by the Spanish Commission of Science and Technology and FEDER, IMDROFLOOD financed by the WaterWorks 2014 co-funded call of the European Commission, CROSSDRO financed by the AXIS (Assessment of Cross(X) – sectorial climate Impacts and pathways for Sustainable transformation) JPI-Climate co-funded call of the European Commission, INDECIS, which is part of ERA4CS, an ERA-NET initiated by JPI Climate, and funded by FORMAS (SE), DLR (DE), BMWFW (AT), IFD (DK), MINECO (ES), ANR (FR), FCT (PT) with co-funding by the European Union (Grant 690462), Irish Research Council COALESCE grant 2019/43
Ultrasoud-Guided diaphragmatic motility evaluation in patients under-going orthopaedic surgery of the upper limb under regional anesthesia using infraclavicular block
Introducción: el bloqueo de plexo braquial por vía infraclavicular ofrece anestesia completa, efectiva y segura para cirugías del miembro superior desde el tercio distal del brazo. El presente estudio evaluó la afectación de la motilidad diafragmática mediante evaluación ecográfica estandarizada en pacientes a quienes se les realizó esta técnica anestésica. Materiales y métodos: se reclutaron 53 pacientes programados para cirugía ortopédica del miembro superior distal al hombro. Se realizó escaneo ultrasonográfico del diafragma de manera bilateral, antes y después de la realización del bloqueo. Se obtuvieron mediciones de motilidad diafragmática en inspiración forzada y espiración, utilizando un transductor Convex de baja frecuencia. Se localizó el punto más profundo de visualización del diafragma que permitiera su seguimiento durante inspiración/espiración en el modo M. Resultados: la medición de la motilidad diafragmática fue hecha de forma estandarizada en todos los pacientes antes y después del bloqueo, mediante una evaluación tanto cualitativa como cuantitativa, a fin de obtener un valor promedio absoluto de 6,63 cm (DE ± 0,35) y 6,75 cm (DE ± 0,42), respectivamente. La prueba de t de Student no mostró diferencia estadísticamente significativa en el desplazamiento diafragmático antes y después de la intervención. Conclusiones: el uso de la ultrasonografía en la evaluación de la motilidad diafragmática es una herramienta simple, no invasiva y reproducible. En el bloqueo de plexo braquial por vía infraclavicular no se encontró evidencia de parálisis diafragmática ipsilateral; sin embargo, el resultado podría estar relacionado con la baja prevalencia de esta complicación en el abordaje evaluado y con la ausencia de estandarización de las variables medidas.Artículo original155-162Introduction: Infraclavicular brachial-plexus block provides complete, effective and safe anesthesia for upper-limb surgical interventions from the distal third of the arm onwards. This study evaluated the possible compromise of dia-phragmatic motility using standardized ultrasonographic evaluation in patients who underwent this anesthetic technique. Methods: 53 patients were recruited for upper-limb orthopedic surgery distal to the shoulder. Bilateral ultrasonographic exploration of the diaphragm was made both be-fore and after the regional anesthesia was per-formed. Diaphragmatic motility measurements were taken in forced inspiration and expiration utilizing a Convex, low frequency transducer. The deepest point of diaphragmatic visualization was identified and followed during inspiration and expiration maneuvers using M Mode Ultra-sonography. Results: A standardized measure-ment of diaphragmatic motility was performed in every patient both before and after the block was undertaken. We obtained both qualitative and quantitative measurements obtaining an average absolute value of 6.63 cm (SD±0,35) and 6.75 cm (SD±0.42), respectively. A statisti-cal Student t test was performed demonstrating no significant difference in diaphragm move-ment before and after the anesthetic procedu-re. Discussion: The use of ultrasonography in the evaluation of diaphragmatic motility is asimple, non-invasive and reproducible tool. The-re is no evidence of diaphragmatic paralysis after infraclavicular brachial-plexus block. However, the result may be related toe the low prevalen-ce of this complication and with the absence of normal, standardized values of the variables of interest
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