Purpose
The aim of this paper is to describe the tests carried out on a SRSMapCheck array, to verify its reliability and sensitivity for quality assurance (QA) of high gradient treatments as an ...alternative system to the use of high spatial resolution detectors, such as gafchromic film, whose processing requires meticulous and time‐consuming procedures.
Methods
In an initial step, general functionality tests were carried out to verify that the equipment meets the manufacturer's specifications. A study of the accuracy of the application of correction factors to compensate for variation in detector response due to dose rate, field size and beam angle incidence has been included. Besides, to assess the ability of the array to detect inaccurately delivered treatments, systematic errors corresponding to the deviation in the position of the leaves and the accuracy of the gantry position, have been introduced. Based on these results, an estimate of sensitivity and specificity values of the device has been completed. The final step included a study applied to high gradient treatment for real cases of spatially fractionated radiotherapy, where the results of SRSMapCheck measurements have been compared with gafchromic films.
Results
General commissioning tests meet the manufacturer's specifications. dose rate (DR) response variation is better than 1.5% and for DR above 50 MU/min better than 1%. The results for beam incidences are better than 1% for all gantry angles, including beam incidences parallel to the array. Field size response differences are within the range of ±1% for sizes up to 2 × 2 cm2, with a maximum value obtained of 3.5%, for 1 × 1 cm2. From the systematic error study, using a Gamma function Γ (2%, 2 mm), the detector presents a high specificity with a value greater than 90% at its lower limit, while its sensitivity has a moderate mean value of 81%. Sensitivity values increase above 86% when we apply a Gamma function Γ (2%, 1 mm) is applied. Finally, the study of actual cases comprises 17 patients, distributed into 11 lung tumors, 3 gynecological and 3 soft tissue tumors. The gafchromic film showed a lower passing rate with an average value of Γ (2%, 2 mm) = 94.1% compared to Γ (2%, 2 mm) = 98.6% reached by the measurements with the array.
Conclusions
Gamma function obtained with the SRSMapCheck array always presented a higher value than gafchromic film measurements, resulting in a greater number of plans considered correct. This fact, together with the sensitivity and specificity study carried out, allows us to conclude the recommendation that a restrictive metric must be established, in this way we will improve sensitivity, and therefore we will reduce the rate of incorrect plans qualified as correct. The characteristics of the equipment together with the correction factors applied, led to reliably performing acquisitions for complex treatments with multiple small targets in oblique rotational incidences. The spatial resolution of detectors allows the verification of high gradient dose plans such as those achieved in spatially fractionated radiotherapy (SFRT).
It is unclear whether the insertion of an axis-orienting double-pigtail plastic stent (DPS) through biliary lumen-apposing meal stent (LAMS) in EUS-guided choledochoduodenostomy (CDS) improves the ...stent patency. The aim of this study is to determine whether this technical variant offers a clinical benefit in EUS-guided biliary drainage (BD) for the management of distal malignant biliary obstruction.
This is a multicenter open-label, randomized controlled trial with two parallel groups. Eighty-four patients with malignant biliary obstruction will undergo EUS-BD (CDS type) using LAMS in 7 tertiary hospitals in Spain and will be randomized to the LAMS and LAMS plus DPS groups. The primary endpoint is the rate of recurrent biliary obstruction, as a stent dysfunction parameter, detected during follow-up. Secondary endpoints: technical and clinical success (reduction in bilirubin > 50% within 14 days of stent placement), safety, and others (number of reinterventions, time to biliary obstruction, prognostic factors, survival rate).
The BAMPI trial has been designed to determine whether the addition of a coaxial axis-orienting DPS through LAMS is superior to LAMS alone to prevent stent dysfunction.
ClinicalTrials.gov NCT04595058 . Registered on October 14, 2020.
A switchable molecular device is constructed by contacting an individual nanoparticle based on spin‐crossover molecules between nanometer‐spaced electrodes. The switching and memory effects near room ...temperature are a consequence of the intrinsic bistability of the nanoparticle. Interestingly, for molecular spintronics, the spin crossover can also be induced by applying a voltage, showing that its magnetic state is electrically controllable.
Hyperammonaemia is central in the pathogenesis of hepatic encephalopathy. It also has pleiotropic deleterious effects on several organ systems, such as immune function, sarcopenia, energy metabolism ...and portal hypertension. This study was performed to test the hypothesis that severity of hyperammonaemia is a risk factor for liver-related complications in clinically stable outpatients with cirrhosis.
We studied 754 clinically stable outpatients with cirrhosis from 3 independent liver units. Baseline ammonia levels were corrected to the upper limit of normal (AMM-ULN) for the reference laboratory. The primary endpoint was hospitalisation with liver-related complications (a composite endpoint of bacterial infection, variceal bleeding, overt hepatic encephalopathy, or new onset or worsening of ascites). Multivariable competing risk frailty analyses using fast unified random forests were performed to predict complications and mortality. External validation was carried out using prospective data from 130 patients with cirrhosis in an independent tertiary liver centre.
Overall, 260 (35%) patients were hospitalised with liver-related complications. On multivariable analysis, AMM-ULN was an independent predictor of both liver-related complications (hazard ratio 2.13; 95% CI 1.89–2.40; p <0.001) and mortality (hazard ratio 1.45; 95% CI 1.20–1.76; p <0.001). The AUROC of AMM-ULN was 77.9% for 1-year liver-related complications, which is higher than traditional severity scores. Statistical differences in survival were found between high and low levels of AMM-ULN both for complications and mortality (p <0.001) using 1.4 as the optimal cut-off from the training set. AMM-ULN remained a key variable for the prediction of complications within the random forests model in the derivation cohort and upon external validation.
Ammonia is an independent predictor of hospitalisation with liver-related complications and mortality in clinically stable outpatients with cirrhosis and performs better than traditional prognostic scores in predicting complications.
We conducted a prospective cohort study evaluating the association of blood ammonia levels with the risk of adverse outcomes in 754 patients with stable cirrhosis across 3 independent liver units. We found that ammonia is a key determinant that helps to predict which patients will be hospitalised, develop liver-related complications and die; this was confirmed in an independent cohort of patients.
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•Ammonia is an independent predictor of both hospitalisation with liver-related complications and mortality in stable outpatients with cirrhosis.•Ammonia performs better than traditional severity scores in predicting liver-related complications.•A cut-off level of 1.4x the upper limit of normal ammonia defines the risk of both hospitalisation with liver-related complications and mortality.•Ammonia is a key variable for the prediction of liver-related complications in a derivation cohort and upon external validation.
Trees and herbs that produce fruits represent the most valuable agricultural food commodities in the world. However, the yield of these crops is not fully achieved due to biotic factors such as ...bacteria, fungi, and viruses. Viruses are capable of causing alterations in plant growth and development, thereby impacting the yield of their hosts significantly. In this work, we first compiled the world's most comprehensive list of known edible fruits that fits our definition. Then, plant viruses infecting those trees and herbs that produce fruits with commercial importance in the global market were identified. The identified plant viruses belong to 30 families, most of them containing single-stranded RNA genomes. Importantly, we show the overall picture of the host range for some virus families following an evolutionary approach. Further, the current knowledge about plant-virus interactions, focusing on the main disorders they cause, as well as yield losses, is summarized. Additionally, since accurate diagnosis methods are of pivotal importance for viral diseases control, the current and emerging technologies for the detection of these plant pathogens are described. Finally, the most promising strategies employed to control viral diseases in the field are presented, focusing on solutions that are long-lasting.
Nanoparticles of iron(II) triazole salts have been prepared from water−organic microemulsions. The mean size of the nanoparticles can be tuned down to 6 nm in diameter, with a narrow size ...distribution. A sharp spin transition from the low spin (LS) to the high spin (HS) state is observed above room temperature, with a 30−40-K-wide thermal hysteresis. The same preparation can yield second generation nanoparticles containing molecular alloys by mixing triazole with triazole derivatives, or from metallic mixtures of iron(II) and zinc(II). In these nanoparticles of 10−15 nm, the spin transition “moves” towards lower temperatures, reaching a 316 K limit for the cooling down transition and maintaining a thermal hysteresis over 15−20-K-wide. The nanoparticles were characterized by dynamic light scattering, TEM, and AFM, after deposition on gold or silicon surfaces. The spin transition was characterized by magnetic susceptibility measurements and EXAFS (in solid samples after solvent removal) and also by the color change between the LS (violet) and HS (colorless) states in an organic solvent suspension. The discovery of bistable magnetic nanoparticles of 6 nm with a wide thermal hysteresis above room temperature showcases the actual possibilities of spin crossover materials for nanotechnological applications.
This article describes a high‐order well‐balanced central finite volume scheme for solving the coupled Exner−shallow water equations in one dimensional channels with rectangular section and variable ...width. Such numerical method may solve the proposed bedload sediment transport problem without the need to diagonalize the Jacobian matrix of flow. The numerical scheme uses a Runge–Kutta method with a fourth‐order continuous natural extension for time discretization. The source term approximation is designed to verify the exact conservation property. Comparison of the numerical results for two accuracy tests have proved the stability and accuracy of the scheme. The results of the laboratory tests have also been used to calibrate different expressions of the solid transport discharge in the computer code. Two experimental tests have been carried out to study the erosive phenomenon and the consequent sediment transport: one test consisting of a triangular dune, and other caused by the effect of channel contraction.
The structure of Fe(Htrz)2(trz)BF4 (1, Htrz =1,2,4-4-H-triazole, trz = 1,2,4-triazolate) at the low-spin (LS) and high-spin (HS) states and structural transitions between the two states were ...investigated by in situ high-resolution synchrotron X-ray powder diffraction (XRPD) combined with Raman spectroscopy using a modulation-enhanced technique. The crystal structures of the LS and HS states were determined. A 1D chain structure of 1 at both LS and HS states was proven, and the lattice expansion upon LS−HS transition was mainly caused by the elongation of the chain. The differences in the behavior of the spin transition observed by XRPD and Raman spectroscopy were explained by the local sensitivity of the two different techniques and also by the spatial propagation of spin crossover phase transition within the crystallite and the body of the grain. Moreover, we demonstrated that the two-dimensional correlation analyses facilitate (i) understanding the data obtained by combined techniques, (ii) clarifying correlation between the signals gained by the different probes, and (iii) extracting information on temporal evolution of transformation processes.
Nanoparticles exhibiting a cooperative spin transition, prepared using the reverse micelle technique, are reported. A 40 K magnetic hysteresis is observed near room temperature for ...Fe(Htrz)2(trz)(BF4) nanoparticles (where trz is a triazole derivative) of 11 ± 5 nm in diameter. The figure shows the nanoparticles in octane in the low‐spin state (left) and the high‐spin state (right).
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