Quantifying the Consistency and Characterizing the Confidence of Coronal Holes Detected by Active Contours without Edges (ACWE)

This paper presents an intramethod ensemble for coronal hole (CH) detection based on the Active Contours Without Edges (ACWE) segmentation algorithm. The purpose of this ensemble is to develop a confidence map that defines, for all on disk regions of a Solar extreme ultraviolet (EUV) image, the likelihood that each region belongs to a CH based on that region's proximity to, and homogeneity with, the core of identified CH regions. CHs are regions of open magnetic field lines, resulting in high speed solar wind. Accurate detection of CHs is vital for space weather prediction. By relying on region homogeneity, and not intensity (which can vary due to various factors including line of sight changes and stray light from nearby bright regions), to define the final confidence of any given region, this ensemble is able to provide robust, consistent delineations of the CH regions. Using the metrics of global consistency error (GCE), local consistency error (LCE), intersection over union (IOU), and the structural similarity index measure (SSIM), the method is shown to be robust to different spatial resolutions and different intensity resolutions. Furthermore, using the same metrics, the method is shown to be robust across short timescales, indicating self-consistent segmentations. Finally, the accuracy of the segmentations and confidence maps are validated by considering the skewness (i.e., unipolarity) of the underlying magnetic field

Scientists’ Assessments of Research on Lactic Acid Bacterial Bacteriocins 1990–2010

The antimicrobial activity of bacteriocins from lactic acid bacteria has constituted a very active research field within the last 35 years. Here, we report the results of a questionnaire survey with assessments of progress within this field during the two decades of the 1990s and the 2000s by 48 scientists active at that time. The scientists had research positions at the time ranging from the levels of Master’s and Ph.D. students to principal investigators in 19 Asian, European, Oceanian and North American countries. This time period was evaluated by the respondents to have resulted in valuable progress regarding the basic science of bacteriocins, whereas this was not achieved to the same degree with regard to their applications. For the most important area of application, food biopreservation, there were some success stories, but overall the objectives had not been entirely met due to a number of issues, such as limited target spectrum, target resistance, poor yield as well as economic and regulatory challenges. Other applications of bacteriocins such as enhancers of the effects of probiotics or serving as antimicrobials in human clinical or veterinary microbiology, were not evaluated as having been implemented successfully to any large extent at the time. However, developments in genomic and chemical methodologies illustrate, together with an interest in combining bacteriocins with other antimicrobials, the current progress of the field regarding potential applications in human clinical microbiology and food biopreservation. In conclusion, this study illuminates parameters of importance not only for R&D of bacteriocins, but also for the broader field of antimicrobial research

Empowering Antibiotics In The Amr Landscape: Insights From Dendrimer Conjugation In Ali Systems

In the shadow of the AMR crisis, reigniting the antibiotic pipeline has emerged as a pivotal strategy. Despite the urgent need, there has been a decrease in finding new types of natural or synthetic antibiotics over the past forty years. Of the 65 antibiotics introduced in the last two decades, only four were genuinely new pharmacological classes, whilst the remainder were merely derivatives or modifications of pre-existing compounds. This challenge arises from the need to bypass bacterial resistance, which, paradoxically, is also the target.Inspired by a 2006 study that successfully integrated propranolol with a known drug delivery polymer, DAB-PAMAM dendrimer, for enhanced cellular uptake, we advanced this approach by conjugating the antibiotic ciprofloxacin with PAMAM dendrimers. This strategy aims to enhance the antibiotic’s effectiveness by preventing its ejection from cells.The screening results were promising as Escherichia coli showed MIC values of 1.25 µg/µl and Pseudomonas aeruginosa 1-2 µg/µl. Staphylococcus aureus exhibited values, oscillating between 2-4 µg/µl. MIC values, which lowered by a factor of 2 when tested in media other than MHB. The compounds did not result in cytotoxicity nor hemolysis.An important outcome of these experiments was the insight that tackling AMR requires not only identification of suitable candidates, but also require that standardized screening methodologies are in congruence with clinical needs. Therefore, we employed an air-liquid interface (ALI) culture set-up to mimic respiratory epithelial cells’ natural environment. By introducing P. aeruginosa, a severe cause of respiratory infections, we sought to compare its behavior with standard lab screenings, aiming to bridge the gap between conventional lab methods and clinical needs inside the antimicrobial development pipeline

A community dataset for comparing automated coronal hole detection schemes

Automated detection schemes are nowadays the standard approach for locating coronal holes in extreme-UV images from the Solar Dynamics Observatory (SDO). However, factors such as the noisy nature of solar imagery, instrumental effects, and others make it challenging to identify coronal holes using these automated schemes. While discrepancies between detection schemes have been noted in the literature, a comprehensive assessment of these discrepancies is still lacking. The contribution of the Coronal Hole Boundary Working Team in the COSPAR ISWAT initiative to close this gap is threefold. First, we present the first community data set for comparing automated coronal hole detection schemes. This data set consists of 29 SDO images, all of which were selected by experienced observers to challenge automated schemes. Second, we use this community data set as input to 14 widely applied automated schemes to study coronal holes and collect their detection results. Third, we study three SDO images from the data set that exemplify the most important lessons learned from this effort. Our findings show that the choice of the automated detection scheme can have a significant effect on the physical properties of coronal holes, and we discuss the implications of these findings for open questions in solar and heliospheric physics. We envision that this community data set will serve the scientific community as a benchmark data set for future developments in the field.Peer reviewe