Background: Increasing structural and biochemical evidence suggests that post-translational methionine oxidation of proteins is not just a result of cellular damage but may provide the cell with information on the cellular oxidative status. In addition, oxidation of methionine residues in key regulatory proteins, such as calmodulin, does influence cellular homeostasis. Previous findings also indicate that oxidation of methionine residues in signaling molecules may have a role in stress responses since these specific structural modifications can in turn change biological activities of proteins. Findings: Here we use tandem mass spectrometry-based proteomics to show that treatment of Arabidopsis thaliana cells with a non-oxidative signaling molecule, the cell-permeant second messenger analogue, 8-bromo-3,5-cyclic guanosine monophosphate (8-Br-cGMP), results in a time-dependent increase in the content of oxidised methionine residues. Interestingly, the group of proteins affected by cGMP-dependent methionine oxidation is functionally enriched for stress response proteins. Furthermore, we also noted distinct signatures in the frequency of amino acids flanking oxidised and un-oxidised methionine residues on both the C- and N-terminus. Conclusions: Given both a structural and functional bias in methionine oxidation events in response to a signaling molecule, we propose that these are indicative of a specific role of such post-translational modifications in the direct or indirect regulation of cellular responses. The mechanisms that determine the specificity of the modifications remain to be elucidated.

This review includes a comparative survey of cleaning mechanisms for solar power plants, with a focus on their application in arid regions. In these regions, dust accumulation can have a severe and detrimental effect on the productivity of solar arrays. The primary concern of this study is to address the need for a commercially viable cleaning solution and present candidate technologies that show promise in enabling solar technologies in the sun-rich, arid regions of the world. In addition to comparing the cleaning mechanisms categorically, specific examples from each category will be referenced to demonstrate the specific attributes of such tools. The survey will focus primarily on currently available product categories for the analysis, while developing technologies are reviewed for their potential strengths and weaknesses. The categories of cleaning solutions considered in this study include the following: manual cleaning, mechanized cleaning, hydraulic cleaning, installed robotic cleaning and deployable robotic cleaning.

In this paper a new, semi-automated tank calibration method based on advanced robotics is presented that enables enhanced volumetric measurement and calibration of custody/royalty transfer tanks, with an emphasis on those used in the Oil and Gas Industry. This technology offers relevant facilities a rapid and straightforward solution that offers improved precision over traditionally used methods, thus minimizing revenue losses resulting from inaccurately calibrated tanks. The technology developed is a semi-autonomous robotic system capable of calibrating upright cylindrical tanks. To achieve this, a magnetic crawler was designed that incorporates a digital, laser-based ruler that collects data about the offset of the tank circumference along the tank height with reference to the tanks’ base circumference. The technology has been developed in accordance with the requirements of API MPMS 2.2B "Manual of Petroleum Measurement Standards Chapter 2—Tank Calibration Section 2B—Calibration of Upright Cylindrical Tanks Using the Optical Reference Line Method" to ensure alignment with industry standards. The paper will present trials carried out in both the laboratory, during the technology calibration phase, as well as preliminary tests carried out at a tank farm in Jeddah, Saudi Arabia. The feasibility of using a magnetic crawler and the laser ruler configuration was first demonstrated in the lab environment where measurement uncertainty of less than 0.2 mm was documented, compared to the current technique, which yields measurement uncertainties of at least 1mm. As such, due to increased measurement accuracy, the technology enables consequential calibration of tanks every 2 years as opposed to every 5 years using existing solutions. Apart from the measurement accuracy improvement, this method significantly reduced the total time required to carry out the calibration measurements, increasing the efficiency of the process and reducing the down-time of the asset. Other advantages are based on the digital nature of the technology that simplifies data storage, thus allowing significantly more data to be captured. Finally, remote control of the robotic solution enhances operator safety as it eliminates the need for operators to perform calibration activities at elevated heights such as the roof of the tank. The work performed and presented in this paper demonstrates a novel application of robotics in the Oil and Gas Industry that directly impacts operational efficiency while enhancing safety and minimizing revenue losses. Globally, the current lack of accurate and efficient calibration methods impacts the efficiency of the crude supply chain. The work presented here provides a suitable and cost-effective solution to enhance value realization from the sale of liquid petroleum products.