Dynamics of bipolar HiPIMS discharges by plasma potential probe measurements

The plasma potential at a typical substrate position is studied during the positive pulse of a bipolar high-power impulse magnetron sputtering (bipolar HiPIMS) discharge with a Cu target. The goal of the study is to identify suitable conditions for achieving ion acceleration independent on substrate grounding. We find that the time-evolution of the plasma potential during the positive pulse can be separated into several distinct phases, which are highly dependent on the discharge conditions. This includes exploring the influence of the working gas pressure (0.3 – 2 Pa), HiPIMS peak current (10 – 70 A corresponding to 0.5 – 3.5 A/cm2), HiPIMS pulse length (5 – 60 μs) and the amplitude of the positive voltage U+ applied during the positive pulse (0 – 150 V). At low enough pressure, high enough HiPIMS peak current and long enough HiPIMS pulse length, the plasma potential at a typical substrate position is seen to be close to 0 V for a certain time interval (denoted phase B) during the positive pulse. At the same time, spatial mapping of the plasma potential inside the magnetic trap region revealed an elevated value of the plasma potential during phase B. These two plasma potential characteristics are identified as suitable for achieving ion acceleration in the target region. Moreover, by investigating the target current and ion saturation current at the chamber walls, we describe a simple theory linking the value of the plasma potential profile to the ratio of the available target electron current and ion saturation current at the wall.

Robotic Systems in Radiotherapy and Radiosurgery

Purpose of Review This review provides an overview of robotic systems in radiotherapy and radiosurgery, with a focus on medical devices and recently proposed research systems. We summarize the key motivation for using robotic systems and illustrate the potential advantages. Recent Findings. Robotic systems have been proposed for a variety of tasks in radiotherapy, including the positioning of beam source, patients, and imaging devices. A number of systems are cleared for use in patients, and some are widely used, particularly for beam and patient positioning. Summary The need for precise and safe delivery of focused high doses to the target region motivates the use of robots in radiotherapy. Flexibility in the arrangement of beams and the ability to compensate for target motion are key advantages of robotic systems. While robotic patient couches are widely used and robotic beam positioning is well established, brachytherapy robots are mostly considered in a research context.

Distribution of first-reaction times with target regions on boundaries of shell-like domains

We study the probability density function (PDF) of the first-reaction times between a diffusive ligand and a membrane-bound, immobile imperfect target region in a restricted "onion-shell" geometry bounded by two nested membranes of arbitrary shapes. For such a setting, encountered in diverse molecular signal transduction pathways or in the narrow escape problem with additional steric constraints, we derive an exact spectral form of the PDF, as well as present its approximate form calculated by help of the so-called self-consistent approximation. For a particular case when the nested domains are concentric spheres, we get a fully explicit form of the approximated PDF, assess the accuracy of this approximation, and discuss various facets of the obtained distributions. Our results can be straightforwardly applied to describe the PDF of the terminal reaction event in multi-stage signal transduction processes.

Calcium Signaling, Calcineurin and NFAT3 Molecular Pathway in Reprogramming of Fetal Gene (BNP) Expression in Cardiac Hypertrophy and Inhibitors of Cardiac Hypertrophy-Review

G-Protein Coupled Receptor (GPCR) plays a major role in cardiac hypertrophy. Isoproterenol is an agonist which binds to GPCR. This results in the activation of GS subunit. Activated Gs subunit stimulates cAMP mediated pathway. This activates the calcium signaling and elevates the calcium level. Increased calcium activates the phosphatase activity of calcineurin. Activated calcineurin dephosphorylates NFAT in cytoplasm. Dephosphorylated NFAT translocates to nucleus and binds to target region in DNA and activates re-expression of fetal genes in synergy with GATA-4 trascription factor. Reprogramming of fetal genes by NFAT- 3 and GATA-4 results in cardiac hypertrophy. Calcineurin inhibitors and rephosphorylation of NFAT can prevent cardiac hypertrophy.

Distributed multi-robot sweep coverage for a region with unknown workload distribution

This paper considers the scenario where multiple robots collaboratively cover a region in which the exact distribution of workload is unknown prior to the operation. The workload distribution is not uniform in the region, meaning that the time required to cover a unit area varies at different locations of the region. In our approach, we divide the target region into multiple horizontal stripes, and the robots sweep the current stripe while partitioning the next stripe concurrently. We propose a distributed workload partition algorithm and prove that the operation time on each stripe converges to the minimum under the discrete-time update law. We conduct comprehensive simulation studies and compare our method with the existing methods to verify the theoretical results and the advantage of the proposed method. Flight experiments on mini drones are also conducted to demonstrate the practicality of the proposed algorithm.

Detection and Segmentation of Mature Green Tomatoes Based on Mask R-CNN with Automatic Image Acquisition Approach

Since the mature green tomatoes have color similar to branches and leaves, some are shaded by branches and leaves, and overlapped by other tomatoes, the accurate detection and location of these tomatoes is rather difficult. This paper proposes to use the Mask R-CNN algorithm for the detection and segmentation of mature green tomatoes. A mobile robot is designed to collect images round-the-clock and with different conditions in the whole greenhouse, thus, to make sure the captured dataset are not only objects with the interest of users. After the training process, RestNet50-FPN is selected as the backbone network. Then, the feature map is trained through the region proposal network to generate the region of interest (ROI), and the ROIAlign bilinear interpolation is used to calculate the target region, such that the corresponding region in the feature map is pooled to a fixed size based on the position coordinates of the preselection box. Finally, the detection and segmentation of mature green tomatoes is realized by the parallel actions of ROI target categories, bounding box regression and mask. When the Intersection over Union is equal to 0.5, the performance of the trained model is the best. The experimental results show that the F1-Score of bounding box and mask region all achieve 92.0%. The image acquisition processes are fully unobservable, without any user preselection, which are a highly heterogenic mix, the selected Mask R-CNN algorithm could also accurately detect mature green tomatoes. The performance of this proposed model in a real greenhouse harvesting environment is also evaluated, thus facilitating the direct application in a tomato harvesting robot.

Finding Needle in the Haystack: “Kasur’s Bogeyman” Brought to Justice by Geographic Profiling and Mass DNA Screening

This article describes the application of the concept of geographic profiling in hunting a serial child rapist in Kasur, Pakistan. It also discusses, how DNA became the prime witness against the serial rapist in the court of law. In January 2018, the blind rape and murder case of Zainab Amin hit the headlines. Following autopsy and the subsequent forensic examination, the only piece of evidence, the agencies had, was the DNA profile of the perpetrator and the information that the source of DNA profile is a serial child rapist, involved in at least seven more cases. The analysis of all crime sites and the distance between them strongly suggested that the offender most likely was a local resident. Mass DNA screening in the target region was conducted by CSI teams of Punjab forensic science agency. The DNA matched with suspect number 814 who later confessed all his crimes. In Polygraph examination, the offender revealed his modus operandi which was in line with the hypotheses made during the geographic profiling of the crime scenes. Thus, geographic profiling proved to be a very useful investigative tool in predicting the probable location of the criminal involved in a series of crimes.

Analysis of the Dose Drop at the Edge of the Target Area in Heavy Ion Radiotherapy

Background. The dose distribution of heavy ions at the edge of the target region will have a steep decay during radiotherapy, which can better protect the surrounding organs at risk. Objective. To analyze the dose decay gradient at the back edge of the target region during heavy ion radiotherapy. Methods. Treatment planning system (TPS) was employed to analyze the dose decay at the edge of the beam under different incident modes and multiple dose segmentation conditions during fixed beam irradiation. The dose decay data of each plan was collected based on the position where the rear edge of the beam began to fall rapidly. Uniform scanning mode was selected in heavy ion TPS. Dose decay curves under different beam setup modes were drawn and compared. Results. The dose decay data analysis showed that in the case of single beam irradiation, the posterior edge of the beam was 5 mm away, and the posterior dose could drop to about 20%. While irradiation in opposite direction, the posterior edge of the beam was 5 mm away, and the dose could drop to about 50%. In orthogonal irradiation of two beams, the posterior edge of the beam could drop to about 30-38% in a distance of 5 mm. Through the data analysis in the TPS, the sharpness of the dose at the back edge of the heavy ion beam is better than that at the lateral edge, but the generated X-ray contamination cannot be ignored. Conclusions. The effect of uneven CT value on the dose decay of heavy ion beam should also be considered in clinical treatment.

Evaluation of barley testing locations in Ontario

In order to develop new barley cultivars, promising genotypes are evaluated for their performance each year at a number of test locations representing the target region. In this study, we analyzed the Ontario barley registration trial data from 2015 to 2020 to understand the barley mega-environment in Ontario and to evaluate the suitability of the test locations. The analysis showed that the barley test locations fall into two mega-environments, with a major mega-environment consists of five test locations and a minor mega-environment with a single test location. Among the six test locations used for the barley registration trials, Palmerston was found to be the most desirable for the barley cultivar evaluation representing the Ontario barley growing region. This study also identified OB2930-35, a recently released cultivar, to be both high yielding and stable across Ontario. These findings are useful for future barley breeding and cultivar evaluation in Ontario.

Employer Branding – A Human Resource Strategy for Companies in a Turbulent Environment Based on the Example of Northern Austria

Human capital is a precondition for regional development and influences, to a great extent, the value or worth of a region. Especially in a turbulent environment, human capital is a key factor to keep a region competitive and innovative. This paper addresses employer branding as a sustainable strategy for companies, located in the border region of Northern Austria, to manage their human resources. The region is characterized by mostly small and medium sized enterprises which increasingly face labour shortage because numerous residents commute to more urban areas. Hence, employer branding contributes to regional development by attracting and retaining qualified people who not only live in the region but are also willing to work there and invest their talent into the development of new and innovative products or services. An empirical study was conducted to gain insight into how precious human capital can be secured in order to reinforce regional development and encounter the labour shortage problem. Interesting information about employers’ and employees’ values was discovered. Based on the results, companies in the target region require an enhanced human resource strategy in order to be visible for potential employees and to retain existing employees. That is to say, companies that are noticeable and attractive have better chances to entice qualified people which, in turn, positively influences regional development, as people not only live but also work in the region and invest their potential. Talented people not only spur the innovative strength of a company but also determine the success of an organisation. New approaches towards managing human capital and their impact on the target region are presented in this paper.