Autonomous robots path planning: An adaptive roadmap approach

Developing algorithms that allow robots to independently navigate unknown environments is a widely researched area of robotics. The potential for autonomous mobile robots use, in industrial and military applications, is boundless. Path planning entails computing a collision free path from a robots current position to a desired target. The problem of path planning for these robots remains underdeveloped. Computational complexity, path optimization and robustness are some of the issues that arise. Current algorithms do not generate general solutions for different situations and require user experience and optimization. Classical algorithms are computationally extensive. This reduces the possibility of their use in real time applications. Additionally, classical algorithms do not allow for any control over attributes of the generated path. A new roadmap path planning algorithm is proposed in this paper. This method generates waypoints, through which the robot can avoid obstacles and reach its goal. At the heart of this algorithm is a method to control the distance of the waypoints from obstacles, without increasing its computational complexity. Several simulations were run to illustrate the robustness and adaptability of this approach, compared to the most commonly used path planning methods

Synthesis of atomically thin hexagonal boron nitride films on nickel foils by molecular beam epitaxy

Hexagonal boron nitride (h-BN) is a layered two-dimensional material with properties that make it promising as a dielectric in various applications. We report the growth of h-BN films on Ni foils from elemental B and N using molecular beam epitaxy. The presence of crystalline h-BN over the entire substrate is confirmed by Raman spectroscopy. Atomic force microscopy is used to examine the morphology and continuity of the synthesized films. A scanning electron microscopy study of films obtained using shorter depositions offers insight into the nucleation and growth behavior of h-BN on the Ni substrate. The morphology of h-BN was found to evolve from dendritic, star-shaped islands to larger, smooth triangular ones with increasing growth temperature

Spectrally narrow exciton luminescence from monolayer MoS2 exfoliated onto epitaxially grown hexagonal BN

The strong light-matter interaction in transition Metal dichalcogenides (TMDs) monolayers (MLs) is governed by robust excitons. Important progress has been made to control the dielectric environment surrounding the MLs, especially through hexagonal boron nitride (hBN) encapsulation, which drastically reduces the inhomogeneous contribution to the exciton linewidth. Most studies use exfoliated hBN from high quality flakes grown under high pressure. In this work, we show that hBN grown by molecular beam epitaxy (MBE) over a large surface area substrate has a similarly positive impact on the optical emission from TMD MLs. We deposit MoS$_2$ and MoSe$_2$ MLs on ultrathin hBN films (few MLs thick) grown on Ni/MgO(111) by MBE. Then we cover them with exfoliated hBN to finally obtain an encapsulated sample : exfoliated hBN/TMD ML/MBE hBN. We observe an improved optical quality of our samples compared to TMD MLs exfoliated directly on SiO$_2$ substrates. Our results suggest that hBN grown by MBE could be used as a flat and charge free substrate for fabricating TMD-based heterostructures on a larger scale.Comment: 5 pages, 3 figure

The frequency of shiga toxin producing Escherichia coli in patients with urinary tract infection in Iran: Systematic review and meta-analysis

Background and Objectives: Escherichia coli is the main cause of urinary tract infection regardless of age. If it harbors shiga toxin, hemolytic uremic syndrome may occur. The aim of this study was to determine the incidence and prevalence of Shiga Toxin producing E. coli (STEC), as a cause of urinary tract infection in Iran. Methods: Major medical search engines, Iranian scientific search engines, and Iranian databases for thesis were searched for relevant English or Persian keywords for urinary tract infection, shiga-toxin Escherichia coli, and hemolytic uremic syndrome in Iran, which were published between 1985 and 2017. The study was followed by the PRISMA statement. Point prevalence and proportion were calculated by random effect and I2 for heterogeneity and expressed as 95 confidence intervals. MedCalc version 15 and SPSS IBM were used for statistical analysis. Results: A total of six articleswith 1,111 positive E. coli urine cultures met all the inclusion criteria and were eligible for the final analysis. All studies had a cross-sectional design. The qualities of two studies were poor with low to moderate risk of bias. Considering 32 samples reported as positive for STEC, the pooled prevalence for E. coli associated UTI was 3.46 (95 CI, 0.89 to 7.65, I2 = 86). The study was heterogeneous for publication bias. Conclusions: This review indicated that STEC constituted some percentage of uropathogenic E. coli that required to be considered during culture processing and longer clinical follow up of the patients for the occurrence of STEC-related morbidity. © 2018, Author(s)

Graphene-Capped Liquid Thin Films for Electrochemical Operando X-ray Spectroscopy and Scanning Electron Microscopy

Electrochemistry is a promising building block for the global transition to a sustainable energy market. Particularly the electroreduction of CO2 and the electrolysis of water might be strategic elements for chemical energy conversion. The reactions of interest are inner-sphere reactions, which occur on the surface of the electrode, and the biased interface between the electrode surface and the electrolyte is of central importance to the reactivity of an electrode. However, a potential-dependent observation of this buried interface is challenging, which slows the development of catalyst materials. Here we describe a sample architecture using a graphene blanket that allows surface sensitive studies of biased electrochemical interfaces. At the examples of near ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) and environmental scanning electron microscopy (ESEM), we show that the combination of a graphene blanket and a permeable membrane leads to the formation of a liquid thin film between them. This liquid thin film is stable against a water partial pressure below 1 mbar. These properties of the sample assembly extend the study of solid–liquid interfaces to highly surface sensitive techniques, such as electron spectroscopy/microscopy. In fact, photoelectrons with an effective attenuation length of only 10 Å can be detected, which is close to the absolute minimum possible in aqueous solutions. The in-situ cells and the sample preparation necessary to employ our method are comparatively simple. Transferring this approach to other surface sensitive measurement techniques should therefore be straightforward. We see our approach as a starting point for more studies on electrochemical interfaces and surface processes under applied potential. Such studies would be of high value for the rational design of electrocatalysts

On the Job

<p>DPSCs were exposed to various MG132 or p65 siRNA concentrations (A and B, respectively) and cytokines in the presence of MG132 or p65 siRNA (C and D, respectively) for 7 days. Col(I)-α1 mRNA was assayed using qRT-PCR. Data are presented as the mean ± S. E. M. of triplicate measures from triplicate experiments. Symbols: Asterisks (*) indicate statistical comparison with control result; plus signs (+) indicate statistical comparison with IL-1β (0.5 ng/ml) and TNFα (1.0 ng/ml) treatment (low cytokine dose); triangle (Δ) indicates statistical comparison with IL-1β (10.0 ng/ml) and TNFα (20.0 ng/ml) treatment (high cytokine dose). Statistical comparison was made using ANOVA testing with Dunnett’s posthoc analysis. Statistical significance was represented by *, +, or Δ for <i>p</i> < 0.05; **, ++, or ΔΔ for p < 0.01; ***, +++, or ΔΔΔ for p < 0.001.</p

Immigration and Human Development: Evidence from Lebanon

This paper takes Lebanon as a case study to examine the relationship between human development and immigration. It examines this issue from both ends: the sending and the receiving countries. The author suggests that by developing the concept of a diasporic civil society and a diasporic public sphere, a significant aspect of the relationship between human development and immigration is illuminated especially at the level of political, social and cultural capitals. The paper also argues that the double impact of the home country and that of destination has a lot to say about the influence of immigration on human development in Lebanon. In examining Australia as a destination country, the paper shows the particular impact that globalisation and September 11 have lately had on the capacity of the Lebanese migrants for human development. Finally, the paper concludes by showing the extent to which the diasporic civil society compensates for the ‘negligent’ character of the Lebanese state in the context of human development