This fresh approach to teaching Quantum Field Theory examines challenging concepts with a minimum of technical detail. The book treats the discussion of the main ideas as more important than the ...presentation of technical mathematical details.
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A water jet penetrating into a water pool produces air entrainment and bubbles that rise to the surface and disintegrate. A similar scenario can be expected when a granular jet enters ...into water. This phenomenon is common in natural and industrial processes but remains so far unexplored.
A collimated jet of monodisperse silica beads was poured into water and the process was filmed with a high-speed camera. The grain size, jet impact velocity, and the liquid physical properties were systematically varied.
For grains of ~50–300μm in diameter, the granular jet deforms the air-water interface, penetrates the pool and produces air entrainment. Most of the entrained air is contained in the interstitial space of the jet, and its volume is linearly proportional to the volume of grains. The bubbles formed in this process are covered by a layer of grains attached to the bubble air-water interface due to capillary-induced cohesion. These “granular bubbles” are stable over time because the granular shell prevents coalescence and keeps the air encapsulated, either if the bubbles rise to the surface or sink to the bottom of the pool, which is determined by the competition of the buoyancy and the weight of the assembly.
The role of MICA antibodies in acute heart allograft rejection was examined utilizing 190 pre‐ and post‐transplant serum samples from 44 patients collected during the first year after ...transplantation. MICA antibodies were detected by CDC test on recombinant cell lines and by the newly developed Luminex MICA antibody detection assay. Additionally, MICA expression was analyzed by ‘real time’ RT‐PCR and by immunohistochemistry in 10 endomyocardial biopsies. Only two subjects had HLA antibodies post‐transplant. Nevertheless, MICA antibodies were found in a significant number of subjects. The prevalence of MICA antibodies was significantly higher among those with severe acute rejection (AR) than in those without rejection (60.7% vs. 14.3%, p = 0.0038 by CDC; 55.5% vs. 5.7%, p = 0.0020 by Luminex). In most cases, the appearance of MICA antibodies post‐transplant precedes AR. Following transplantation, MICA up‐regulation correlated with histological evidence of severe rejection. Monitoring for MICA antibodies post‐transplant may be useful to establish new risk factors for acute rejection.
In acute heart transplant rejection, anti‐MICA was detectable in a significant number of subjects after heart transplantation and was more frequent among those with severe rejection.
Background
Different methods have been proposed to study skeletal muscle mass in sarcopenia diagnosis, although all have inherent drawbacks. The aim of this study was to evaluate the utility of ...muscle ultrasound in muscle assessment by studying its correlation with dual-energy x-ray absorptiometry (DXA) and calf circumference (CC), cut-off values for ultrasound-based detection of low muscle mass, and the correlation with muscle performance.
Methods
Fifty-seven participants older than 70 years, underwent a muscle ultrasound study, DXA, calf circumference (CC) and functional assessment. Ultrasound measurements were taken in the femoral quadriceps (transverse plane) and in the medial gastrocnemius (transverse and longitudinal planes). Muscle function was assessed by gait speed, Short Physical Performance Battery (SPPB) and grip strength.
Results
Median age was 78.9 years (IQR 74.9–81.9), and 33 were women (57.9%). We found good correlation between muscle thickness of gastrocnemius muscle in transverse and longitudinal plane and appendicular lean mass measured by DXA (r=0.546 and r=0.689 respectively) and good correlations between muscle thickness of gastrocnemius in transverse and longitudinal plane with CC (r=0.651 and r=0.447 respectively). The thickness of gastrocnemius medialis optimal cut-off points for low muscle mass were 18,5mm in the transverse plane (Sensitivity: 77,8%, Specificity: 77,1%), and 17.3mm in the longitudinal plane (Sensitivity: 100%, Specificity: 68.8%). Muscle thickness was also significantly correlated with gait speed, SPPB and grip strength.
Conclusions
Measures of gastrocnemius medialis thickness obtained by ultrasound are reliable and correlate well with DXA and CC values and muscle performance.
A gravity core (220 cm depth) was collected to investigate the geochemistry, enrichment, and pollution of trace metals in anoxic sediments from San Simon Bay, an ecosystem of high biological ...productivity in the northwest of Spain. A five-step sequential extraction procedure was used. The Cu, Pb, and Zn contents decreased with depth, with maximum values in the top layers. Ni and Zn were bound to pyrite fractions, while Cd and Pb were associated with the most mobile fractions. The analyzed metals were associated with the fractions bound to organic matter, mainly with the strongly bound to organic matter fraction. High Cd and Cu values were observed. The fractionation showed a high mobility for Cd (28.3–100%) and Pb (54.0–70.2%). Moreover, the pollution factor and the geoaccumulation index reflected a high contamination for Pb and a moderate contamination for Cu and Zn in the superficial layers, pointing to a possible ecotoxicological risk to organisms in San Simon Bay.
Objectives: The aim was to determine the direct impact of the COVID-19 pandemic on Spain's health budget. Methods: Budget impact analyses based on retrospective data from patients with suspected ...severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) admitted to a Spanish hospital between February 26 and May 21, 2020. Direct medical costs from the perspective of the hospital were calculated. We analyzed diagnostic tests, drugs, medical and nursing care, and isolation ward and ICU stays for three cohorts: patients seen in the emergency room only, hospitalized patients who tested positive for SARS-CoV-2, and patients who tested negative. Results: The impact on the hospital's budget for the 3 months was calculated at €15,633,180, 97.4% of which was related to health care and hospitalization. ICU stays accounted for 5.3% of the total costs. The mean cost per patient was €10,744. The main costs were staffing costs (10,131 to 11,357 €/patient for physicians and 10,274 to 11,215 €/patient for nurses). Scenario analysis showed that the range of hospital expenditure was between €14,693,256 and €16,524,924. The median impact of the pandemic on the Spanish health budget in the sensitivity analysis using bootstrapped individual data was €9357 million (interquartile range IQR, 9071 to 9689) for the conservative scenario (113,588 hospital admissions and 11,664 ICU admissions) and €10,385 million (IQR, 110,030 to 10,758) for the worst-case scenario (including suspected cases). Conclusion: The impact of COVID-19 on the Spanish public health budget (12.3% of total public health expenditure) is greater than multiple sclerosis, cancer and diabetes cost.
The capacity of fluvial potholes to trap sediments, together with the geochemical analysis of their stored sediments for environmental assessment, is an overlooked research topic in small bedrock ...rivers. The present exploratory study is focused on this issue. It was developed in a small river over rock, in the inland territory of Galicia (NW Iberian Peninsula). The study started from an analysis of the inventoried fluvial potholes to identify suitable forms for sampling, and the collection of sediment samples within them. After this, the determination of the grain texture, mineralogy and content of major and trace elements in sediments were carried out. Potholes with maximum vertical depth from 25 cm to 1 m, located in central and sidewall sectors of the bedrock channel, provided the best conditions for sediment sampling. The sediments collected from six potholes showed predominance of coarse-medium grain size and sand fraction. The rough contents of the major and even trace elements are related with the nature of the more refractory minerals of the bedrock. An adequate sampling strategy, considering grain-size fractions, show potential to use trace elements as environmental indicators.
In this work, we report the synthesis and characterization of different kinds of graphene nanomaterials and their applicability to the development of biosensing platforms. We have synthesized ...graphene oxide (GO) following a modified Hummer’s method, which has been subsequently reduced by electrochemical procedures. This reduction strategy precludes the employment of toxic solvents, leading to a product, electrochemically reduced graphene (ERG), free of contaminants. The characterization of the synthesized nanomaterials has been performed by different techniques such as X‐ray diffraction spectroscopy (XRD), Raman spectroscopy, X‐ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The information gathered by this combination of techniques confirms that i) the synthesis methodology affords the production of GO nanosheets, which present a typical lateral dimension of several hundreds of nanometers and a thickness value of 1.3±0.1 nm, ii) the reduction step has been successfully achieved leading to graphene nanosheets free of oxygen functionalities with an average lateral dimension of at least 1 micrometer and a thickness value of 2.8±0.2 nm. Once we have confirmed that both materials have been successfully synthesized, we have studied the effect of the effect of their inclusion in biosensing platforms on the analytical response, selecting a lactate oxidase based biosensor as a model system. We have demonstrated that although the incorporation of GO or ERG to the device results in an enhancement of the analytical response of the resulting biosensing platform, the former system offers slightly better analytical properties and a more reproducible response than the ERG one.
The objective of this study was to generate an ecological niche modeling (ENM) to determine potential sites or areas where the growth and development of halophyte species are the most appropriate. To ...determine the number of halophyte species in the zone of study, the random quadrant method was used. The material collected per site was separated and identified. One hundred samples were taken from the soil at a depth of 20 cm for the analysis of five chemical properties. Evaporation, precipitation, and minimum and maximum temperature data were obtained from 34 meteorological stations. Geostatistical techniques were applied for the spatial prediction of the climate and soil variables. In addition, five scenes from the Sentinel-2A satellite and the digital elevation model were retrieved. Principal component analysis was performed on the 15 environmental predictors. Ten algorithms were used to conduct the ENM. The ENM results of the halophyte species were reclassified in binary maps. A species richness (PRS) map was created according to the predictions from the sum of binary maps. The PRS map was used to define the potential sites to grow and develop halophyte species of anthropogenic interest. Ten halophyte species were found in the sampled zone, of which 70% were native. The first seven principal components (95% of the cumulative variance) were used for the ENM. The AUC values of the halophyte species models ranged from 0.61 to 0.98. A total of 38% of the study area was considered suitable for potential sites of halophyte species.
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