Hydrazine network on Cu(111) surface: A Density Functional Theory approach

We have used first-principles calculations, including a correction for the dispersive forces (DFT-D2), to investigate the arrangement of hydrazine (N2H4) molecules upon adsorption on the Cu(111) surface, showing that surface–molecule interactions affect the process most. Our calculations provide insight into the interplay between lateral adsorbate–adsorbate and vertical adsorbate–substrate interactions. We found that the main contributors to the assembly of the hydrazine layers are the binding interactions between the adsorbates and the substrate. The dispersion forces are predominant in both vertical and lateral interactions, whereas hydrogen-bonding is least important and organisation of the N2H4 monolayers is therefore primarily due to the long-range interactions. Optimised geometries for several hydrazine conformations were found to be coverage-dependent. The electronic properties such as charge density and density of states have been calculated for different hydrazine coverages, and indicated that no charge transfer occurs between molecules. Scanning tunnelling microscopy images were simulated, where the observed protrusions arise from the trans conformers. We also found that the effect of hydrazine adsorption on the Cu(111) surface energy is negligible and further investigation of other Cu facets is needed to determine the N2H4 effect on the nanoparticles' morphology. Finally, we have simulated the temperature programmed desorption of different coverages of hydrazine from the Cu(111) resulting in desorption peaks between 150 and 200 K

Tessier number 30 clefts with congenital heart defects

Introduction: Midline cleft of mandible, classified as Tessier 30 clefts is extremely rare, with less than 100 reported cases in the latest studies. Variations in severity and associated malformations have been reported before. Case Presentation: In this report, we present the first documented Iranian case of Tessier 30 with median cleft of lower lip and bifid tongue concomitant with congenital heart defects. Conclusions: We explain embryologic origin, differential diagnosis, other associated anomalies and its treatment by reviewing literature. © 2015, Iranian Red Crescent Medical Journal

The validity of a scoring system in predicting intravenous immunoglobulin treatment failure in children with kawasaki disease

Background: Between 10 and 20 of children with Kawasaki disease (KD) will not respond to intravenous immunoglobulin (IVIG) treatment, and are prone to coronary abnormalities. A variety of predicting scoring systems, including the Kobayashi system, have been proposed, but have not yet been evaluated using Iranian patients. Objectives: To evaluate the Kobayashi scoring system with regard to predicting response to IVIG treatment in Iranian children. Patients and Methods: All patients who received a final diagnosis of KD at Aliasghar children�s hospital between 1982 and 2013, and who met the inclusion criteria, were enrolled in this retrospective cohort study. We excluded patients with missing data, abnormal echocardiographic finding on admission, late admission, atypical or afebrile cases, and those who had received an insufficient amount of IVIG. We compared demographic and echocardiographic data before IVIG, and within 7 days of treatment, as well as C reactive protein (CRP), sodium, aspartate aminotransferase, platelet levels, neutrophil percentage, age of patients, and duration of fever before IVIG administration, in treatment responders and non-responders. Results: Of the 141 cases, 97 patients met the criteria and were enrolled. Of these, 19 (19.6) did not respond to IVIG. A total of 61.8 of patients were male, and the mean patient age was 36.9 months (SD = 32.1 months). Echocardiographic evaluation revealed early coronary involvement in 15.3 of patients, and coronary abnormalities were diagnosed in 10 of patients within the first 10 days of presentation and concurrent with their IVIG treatment. A between-groups comparison of quantitative CRP, absolute neutrophil count, and platelet count showed that platelet count alone was significantly higher in nonresponders (P = 0.04). With regard to items of Kobayashi scoring system, data were present for just 41 cases, but a significant difference between the two groups was shown, with the treatment-refractory group having a significantly higher score (P = 0.002). Receiver-operating characteristic curve analysis revealed that the optimum cut-off point for our population would be 2, which makes the sensitivity of the test equal to 75, with a specificity of 60. Conclusions: This preliminary study showed that patients with KD and a high Kobayashi score are at greater risk of being unresponsive to IVIG treatment. Further studies, preferably multicenter evaluations, are required in order to understand the exact application of various scoring systems in the management of people with KD in Iran. © 2016, Pediartric Infections Research Center

Emergence of protective behaviour under different risk perceptions to disease spreading

The behaviour of individuals is a main actor in the control of the spread of a communicable disease and, in turn, the spread of an infectious disease can trigger behavioural changes in a population. Here, we study the emergence of individuals protective behaviours in response to the spread of a disease by considering two different social attitudes within the same population: concerned and risky. Generally speaking, concerned individuals have a larger risk aversion than risky individuals. To study the emergence of protective behaviours, we couple, to the epidemic evolution of a susceptible-infectedsusceptible model, a decision game based on the perceived risk of infection. Using this framework, we find the effect of the protection strategy on the epidemic threshold for each of the two subpopulations (concerned and risky), and study under which conditions risky individuals are persuaded to protect themselves or, on the contrary, can take advantage2022 The Author(s) Published by the Royal Society. All rights reserved. © 2022 Royal Society Publishing. All rights reserved

Experimental Evaluation of Geocell and EPS Geofoam as Means of Protecting Pipes at the Bottom of Repeatedly Loaded Trenches

© 2020 American Society of Civil Engineers. With growing populations and continuing urban development, embedding pipes in the ground that are then overrun by traffic is inevitable. This paper describes full-scale prototype tests on high-density polyethylene (HDPE) flexible pipes (of 250 mm diameter), buried at shallow depth, under simulated traffic loading. The paper studies the effect of surface load diameter (0.6×, 0.8×, and 1× pipe diameter) and the amplitude of repeated load (400 or 800 kPa) on pipe behavior. The effects of expanded polystyrene (EPS) geofoam blocks of various densities and also of geocells as a three-dimensional (3D) reinforcement in reducing the pressure transferred to the pipe, the deformation of the pipe, and the surface settlement of the backfill were investigated. The results show that, with an increase in loading surface diameter, the pipe's vertical diametral strain, the pressure transferred to the pipe, and the surface settlement grow significantly, irrespective of applied pressure. Using an EPS block over the pipe increases the soil settlement but reduces transferred pressure onto the pipe and, consequentially, results in lower pipe deformations. The increase in density of an EPS block helps improve response but was still found to be insufficient to prevent increase in surface deflections. The use of geocell reinforcement beneath the loading surface not only reduces the pressure transferred to the pipe and decreases its deformation but also significantly negates the tendency of the EPS block to increase the soil surface settlement. Thus, a geocell reinforcement layer placed over two EPS geofoam blocks (with total thickness 0.3× and width 1.5× the pipe diameter) all above a pipe buried at a depth of twice the pipe diameter, was found to deliver an acceptable, stable response. By these means, the vertical pipe strain, transferred pressure over the pipe, and soil surface settlement were reduced, respectively, by 0.45, 0.37, and 0.53× those obtained for the comparable unmodified buried pipe installation and are within allowable limits

Study of the Current Sheath Velocity in a 2.2 kJ Plasma Focus Device

In this article, after a brief introduction of MTPF-1 plasma focus device, some of the related  experimental data are presented. These data show that it is possible to select the proper gas pressure and discharge voltage in order to have a specified pinch time interval. In addition, the effects of gas pressure and discharge voltage on the current sheath’s mean velocity have also been studied. This study showed that, in the case of argon, the maximum value of the current sheath’s mean velocity is about 5 cm/µs, where it can be obtained under various combinations of the pressures and discharge voltages. By using the speed factor concept, the velocity of the current sheath at the pinch time was also examined. It was determined that in two separate experiments with different gas pressures and discharge voltages, the equality of the pinch times means the approximate equality of the current sheath radial velocities