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Background Both drug‐coated balloon (DCB) angioplasty and conventional plain balloon angioplasty (PBA) can be implemented to treat hemodialysis dysfunction. The present study aims to compare the safety and efficacy of these 2 approaches by conducting a meta‐analysis of available randomized controlled trials. Methods and Results PubMed, Cochrane Library, and Embase databases were queried from establishment to January 2021. A total of 18 randomized controlled trials including 877 and 875 patients in the DCB and PBA groups, respectively, were included in the present meta‐analysis. Target lesion primary patency, circuit patency, target lesion revascularization, and mortality were pooled. Odds ratios (ORs) were reported with 95% CIs. Publication bias was analyzed with funnel plot and Egger test. Target lesion primary patency was higher among patients who underwent DCB (OR, 2.93 [95% CI, 2.13–4.03], P P P P =0.005]). Compared with the PBA group, the DCB group had lower odds of target lesion revascularization during follow‐up (OR, 0.43 [95% CI, 0.23–0.82], P =0.001 at 6 months; OR, 0.74 [95% CI, 0.32–1.73], P =0.490 at 1 year). The OR of mortality was comparable between 2 groups at 6 months (OR, 1.18; 95% CI, 0.42–3.33 [ P =0.760]) and 1 year (OR, 0.93; 95% CI, 0.58–1.48 [ P =0.750]). Conclusions Based on evidence from 18 randomized controlled trials, DCB angioplasty is superior to PBA in maintaining target lesion primary patency and circuit patency among patients with dialysis circuit stenosis. DCB angioplasty also reduces target lesion revascularization with a similar risk of mortality compared with PBA.

Given the current water shortage in North Africa, improving water management to produce more crop per drop is vital. In addition, the introduction of drought-tolerant, less water-consuming crops such as quinoa is of great interest. To understand the response of quinoa to water stress in terms of biomass and grain yield under various irrigation management strategies, the SALTMED model was employed using field measurements during the cropping seasons of 2011 and 2012 at a site in the Marrakech region, south Morocco. Quinoa showed its ability to grow in the south of Morocco and give a good yield under full irrigation. However, the experimental and modelling results showed that under rainfed and deficit irrigation, the grain yield was lower than under the full irrigation treatment and was dependent on water deficit level. The study revealed that a reasonable grain yield of quinoa can only be obtained if it was subjected to moderate water stress conditions. The results indicated that the SALTMED model is able to simulate the quinoa biomass and grain yield under various water deficit levels and that the model can be used in the evaluation of different irrigation strategies.

Radiochromic film (RCF) has been shown to be a precise and accurate secondary planar dosimeter for acute exposure radiation fields. However, its application to low dose-rate brachytherapy has been questioned because of possible dose-rate effects. To address this concern, we have measured the optical density (OD) of Model 55-2 RCF as a function of time (interval between the completion of irradiation and densitometry using a 633 nm laser scanner) following exposure (from less than 1 hour to 90 days) for single and split doses from 1 Gy to 100 Gy. Our work demonstrates that film darkening as a function of post-irradiation time depends significantly on total dose, with films exposed to lower doses developing faster than films given higher doses. At 1 Gy, the OD 90 days after exposure is 200% larger than that measured 1 h after exposure compared to a 20% increase over 90 days for doses larger than 20 Gy. An empirical model with time-independent, fast and slow growth terms was used to fit single exposure data. The dependence of the resulting best-fit parameters on dose was investigated. Splitting the dose into two fractions (20 Gy followed by doses of 1-80 Gy 24 h later) results in modest post-irradiation time-dependent changes in the total optical density (at most 15% at small doses), which dissipates within 20 hours following the second exposure. This experimental finding is consistent with the predictions of a simple cumulative dose superposition model. Overall, both experimental and empirical modeling suggest that dose-rate effects may be relatively small despite the strong dependence of film darkening kinetics on total dose. However, more experimental evaluation of radiochromic film response dependence on dose rate and dose-time-fractionation patterns is needed.

Purpose: To test the amorphous silicon (aSi) electronic portal imaging device(EPID) for quality assurance (QA) of the multi‐leaf collimators(MLC) and to validate its use as a dynamic intensity‐modulated radiation therapy(IMRT) QA device. Method and Materials: Established MLC QA for IMRT utilizes dosimetric outputs from a single point in phantom with a chamber, and radiographic film to capture the density‐pattern of the MLC. We propose using the aSi EPID 2D‐density distribution to replace the chamber/film for MLC QA, and to verify the dosimetry and mechanics of the MLC for IMRT. A protocol was developed to acquire QA data from the aSi EPID to provide tests for high dose gradients, average output doses, mechanical leaf stability, speed and positioning. The effects of various EPID exposed areas (2×2, 4×4, 6×6 cm2) were used for intercomparison measurements with ion chamber and film. Results:Radiographic film output at gantry angle 270° relative to 0° varies by less than 2%, while the film measurements at other gantry/collimator angles agree within 1% with the ionization chamber. For the same conditions, EPID outputs vary by 1%–5% depending upon exposed area. Output variations may be due to mechanical shifts, gantry and EPID sag, or MLC drifts due to gravity. Minimizing these effects is under further investigation. Conclusion: A method has been developed to utilize the aSi EPID for MLC QA. The 2D density distributions of the EPID offer the potential for more quantitative analysis, and this procedure can be integrated into a routine program for comprehensive dynamic MLC‐based IMRT and EPID QA. Conflict of Interest: This work supported in‐part by Varian Medical Systems.

By inspection of photographs of the Hubble Atlas of Galaxies the frequency distribution of the sizes of dark cloud complexes in the four nearby galaxies NGC 3031, 5128, 5194 and 5457 is derived and the total amount of dust in these systems is estimated. The frequency distribution of the clouds is nearly the same in all the considered galaxies and may be approximated by n(R) ∼ e−kR, k ≈ 0.050 pc−1. The total amount of dust yields to roughly 106M⊙. Die Grosenverteilung von Dunkelwolkenkomplexen in den benachbarten Galaxien NGC 3031, 5128, 5194 und 5457 wurde aus einer Durchmusterung des Hubble-Atlas der Galaxien erhalten. Es ergab sich in allen betrachteten Fallen annahernd die gleiche Verteilung, die durch n(R) ∼ e−kR mit k ≈ 0.050 pc−1 angenahert werden kann. Ferner ergaben sich die Gesamtmassen des in den Dunkelwoken konzentrierten interstellaren Staubes dieser vier Galaxien zu nahezu 106M⊙.

The areas of 267 dark clouds in the galaxy NGC 253 were measured. It is shown that the size distribution of these clouds obeys the same exponential formula found for the galaxies NGC 3031, 5128, 5194, and 5457. From the apparent size distribution of the dark clouds the amount of dust and the distance of NGC 253 is found to 4.4 · 107M⊙ and 2.06 Mpc, respectively. Es wurden die Flachen von 267 Dunkelwolken in der Galaxie NGC 253 vermessen. Es wird gezeigt, das die Grosenverteilung dieser Wolken dem gleichen Exponentialausdruck genugt, der fur die Galaxien NGC 3031, 5128, 5194 und 5457 gefunden wurde. Aus der Verteilung der scheinbaren Grosen der Dunkelwolken wird die Staubmenge in NGC 253 zu 4.4 · 108M⊙ und ihre Entfernung zu 2.06 Mpc abgeleitet.