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Zincophorin is a polyketide antibiotic that possesses potent activity against Gram-positive bacteria, including human pathogens. While a number of total syntheses of this highly functionalized natural product were reported since its initial discovery, the genetic basis for the biosynthesis of zincophorin has remained unclear. In this study, the co-linearity inherent to polyketide pathways was used to identify the zincophorin biosynthesis gene cluster in the genome of the natural producer HKI 0741. Interestingly, the same locus is fully conserved in the streptomycin-producing actinomycete IFO 13350, suggesting that the latter bacterium is also capable of zincophorin biosynthesis. Biological profiling of zincophorin revealed a dose-dependent inhibition of the Gram-positive bacterium . The antibacterial effect, however, is accompanied by cytotoxicity. Antibiotic and cytotoxic activities were completely abolished upon esterification of the carboxylic acid group in zincophorin.

Hydrogen-powered fuel cells will play a vital role in the next generation of energy systems. In this regard, Proton Exchange Membrane Fuel Cells (PEMFC) represent a promising technical solution for all applications where direct electrification is not technically feasible or economically viable, such as the propulsion of heavy vehicles. However, robust production of high-quality fuel cell systems in scalable series production can only be achieved by an early assurance of the product quality considering the numerous variations on geometry element, part, and assembly level. This article presents the challenges and outlines the vision of a geometry assurance process capable of simulating the probabilistic assembly behavior of PEMFC stacks by multi-physics variation simulation, e.g., considering aspects of Finite Element Analysis and Computational Fluid Dynamics, under a realistic representation of the part manufacturing and assembly processes and their operation under variations. The findings reveal future research directions fostering the series production of robust, high-quality PEMFC stacks. [ABSTRACT FROM AUTHOR]

Sampling-based tolerance analysis is a powerful tool for evaluating the quality of functional products, but requires realistic manufacturing distributions. However, the determination of resulting manufacturing distributions is usually associated with a high financial and time expenditure, especially for novel technologies such as Additive Manufacturing. Usually, sampling techniques are used to reproduce the original distribution of manufacturing variations based on statistical moments. In most cases, simplifying assumptions are made for this purpose, potentially leading to an inadequate representation of the correlation between machine and process parameters in the resulting distribution. In the worst case, this can lead to a falsification of the tolerance analysis results. Aiming to address this challenge, this paper presents an approach to imitate real-world manufacturing distributions using generative Machine Learning techniques based on Deep Learning with small real data sets. This enables a realistic reproduction of quasi-real manufacturing distributions and omits conventional sampling techniques. The general procedure and its applicability are shown via illustrative use cases from the tolerancing domain. [ABSTRACT FROM AUTHOR]

We present the results obtained using spectroscopic data taken with the intermediate-resolution Multi Unit Spectroscopic Explorer (MUSE) of B and A-type supergiants and bright giants in the Sculptor Group galaxy NGC 300. For our analysis, a hybrid local thermodynamic equilibrium (LTE) line-blanketing+non-LTE method was used to improve the previously published results for the same data. In addition, we present some further applications of this work, which includes extending the flux-weighted gravity luminosity relationship (FGLR), a distance determination method for supergiants. This pioneering work opens up a new window to explore this relation, and also demonstrates the enormous potential of integral field spectroscopy (IFS) for extragalactic quantitative stellar studies. [ABSTRACT FROM AUTHOR]

The Biere #1‐22 oil production well near Poplar, Montana leaked brine and light nonaqueous phase liquid (LNAPL) to the shallow alluvial aquifer for several years before final closure in 2002. Since 2008, 2.5 billion L of brine have been removed (~90% of the original Cl mass). However, Cl will not reach the original background levels due to the reservoir of solutes entrained in the Bearpaw bedrock remnant from the lateral dense aqueous phase liquid flow across the alluvial/bedrock interface. After removal of ~100,000 L of product since 2006, residual LNAPL is now confined to 2.2 ha (5.5 acres) a decrease from the original 2.7 ha (6.6 acres) areal extent by 17%. The initial ~7.5 m thick product in 2002 is stable at a maximum of ~1 m. However, LNAPL has infiltrated into fine‐grained clay/silt units forming a smear zone in lenses 10 to 20 m bgs. Ongoing remediation has successfully mitigated benzene groundwater impacts over the last 14 years, with the benzene plume area having decreased by >99% (at the 5 μg/L) level from the maximum ~140 ha in 2002. This appears to be the first study evaluating the challenges to remediate a mixed LNAPL/dissolved organic/inorganic plume. Based on the mass removal to date, the asymptotic trends in solute concentrations, unpotable background groundwater quality, absence of a source/receptor pathway, lack of beneficial groundwater use, duration of mitigation with no obvious future accrual in benefit and the availability of institutional controls, it seems that the remedial strategies employed since 2006 have met their cost/benefit goals. [ABSTRACT FROM AUTHOR]

The wide‐field spectroscopic survey telescope (WST) is proposed to become the next large optical/near infrared facility for the European southern observatory (ESO) once the extremely large telescope (ELT) has become operational. While the latter is optimized for unprecedented sensitivity and adaptive‐optics assisted image quality over a small field of view, WST addresses the need for large survey volumes in spectroscopy with the light‐collecting power of a 10‐m class telescope. Its unique layout will feature the combination of multi‐object and integral field spectroscopy simultaneously. For the intended capacity of this layout, a very large number of detectors are needed. The complexity of the detector systems presents a number of challenges that are discussed with a focus on novel approaches and innovative detector designs that can be expected to emerge over the anticipated 20‐year timeline of this project. [ABSTRACT FROM AUTHOR]

Image sensors, most notably the Charge Coupled Device (CCD), have revolutionized observational astronomy as perhaps the most important innovation after photography. Since the 50th anniversary of the invention of the CCD has passed in 2019, it is time to review the development of detectors for the visible wavelength range, starting with the discovery of the photoelectric effect and the first experiments to utilize it for the photometry of stars at Sternwarte Babelsberg in 1913, over the invention of the CCD, its development at the Jet Propulsion Laboratory, to the high‐performance CCD and complementary metal‐oxide‐semiconductor imagers that are available off‐the‐shelf today. [ABSTRACT FROM AUTHOR]

To better understand the impact of the avalanche gain applied in the detector technology and apply this technology in our in‐house astrophotonic projects, we have characterized a C‐RED One camera and produced a stable and reliable method for calculating the system gain at any desired avalanche gain setting. We observed that depending on how the system gain is obtained, multiplying the system gain times the avalanche gain may not accurately produce a conversion factor from electrons to ADUs. As the acquisition of a photon transfer curve (PTC) was possible at different avalanche gain levels, several PTCs at low avalanche gain levels were acquired. Consequently, a linear fit was produced from the acquired system gain as a function of the avalanche gain setting. Through the linear fit, the effective system gain was calculated at any desired avalanche level. The effective system gain makes possible to accurately calculate the initial system gain without the ambiguity introduced by the nonlinearity of the system. Besides, the impact of the avalanche gain on the dynamic range was also analyzed and showed a stable behavior through the measured avalanche range. [ABSTRACT FROM AUTHOR]

For near‐infrared ground and space‐based astronomy, compact photonic devices can replace the large bulk optical components in spectrographs, frequency combs, beam combiners, and sky subtraction filters, thus saving cost, reducing volume, weight, and power requirements. Photonic integrated circuits (PICs), analogous to integrated circuits (IC) in electronics, are particularly powerful to address innovative miniaturized solutions. Here, we demonstrate two new instrument prototypes: the Potsdam Arrayed Waveguide Spectrograph (PAWS) built around an array waveguide grating (AWG) PIC and Hawaii2RG detector, and the Potsdam Comb (POCO), a frequency comb generated by nonlinear processes in a micro‐ring resonator photonic chip. PAWS is calibrated by the remotely located POCO via the fiber optic communication network of the Leibniz‐Institute for Astrophysics Potsdam (AIP). The vision of future astrophotonic solutions for instrumentation is pointing toward hybrid solutions of PIC and detector arrays that hold the promise to dramatically change the layout of telescope focal plane instrumentation. [ABSTRACT FROM AUTHOR]

The Potsdam Arrayed Waveguide Spectrograph (PAWS) is based on an integrated photonic spectrograph designed and developed by innoFSPEC to work in the astronomical H‐band. PAWS demonstrates how a traditional bulk optics spectrograph can be miniaturized and additionally serves as a tool for testing in‐house developed astrophotonical devices. The main element is a second‐generation Arrayed Waveguide Grating (AWG) with unprecedented performance in terms of spectral resolution and throughput that is fiber‐coupled and works as a first dispersive component. The pre‐dispersed light is fed into a free‐space optical system located in a cryostat, where the overlapping spectral orders are separated by cross‐dispersion. The resulting echellogram is recorded by a Teledyne 2k×2k H2RG near‐infrared array. Once the cryogenic cross‐dispersion optics inside the vacuum chamber were appropriately aligned to the AWG coupling optics outside of the chamber, different light sources were used to test the functionality of the complete system. A tunable laser source was used to create an echellogram through frame stacking. Additionally, the cross‐dispersed output of a supercontinuum source was recorded using different input waveguides of the AWG, and first light was achieved with laboratory measurements. PAWS represents a pioneering demonstration of an astronomy‐optimized AWG chip, exhibiting the advantageous capabilities of integrated photonic spectrographs, in particular in the context of space applications. [ABSTRACT FROM AUTHOR]

Convolutional neural networks (CNNs) have been used for a wide range of applications in astronomy, including for the restoration of degraded images using a spatially invariant point spread function (PSF) across the field of view. Most existing development techniques use a single PSF in the deconvolution process, which is unrealistic when spatially variable PSFs are present in real observation conditions. Such conditions are simulated in this work to yield more realistic data samples. We propose a method that uses a simulated spatially variable PSF for the T80-South (T80-S) telescope, an 80-cm survey imager at Cerro Tololo (Chile). The synthetic data use real parameters from the detector noise and atmospheric seeing to recreate the T80-S observational conditions for the CNN training. The method is tested on real astronomical data from the T80-S telescope. We present the simulation and training methods, the results from real T80-S image CNN prediction, and a comparison with space observatory Gaia. A CNN can fix optical aberrations, which include image distortion, PSF size and profile, and the field position variation while preserving the source's flux. The proposed restoration approach can be applied to other optical systems and to post-process adaptive optics static residual aberrations in large-diameter telescopes. [ABSTRACT FROM AUTHOR]

Aims. We perform a deep survey of planetary nebulae (PNe) in the spiral galaxy NGC 300 to construct its planetary nebula luminosity function (PNLF). We aim to derive the distance using the PNLF and to probe the characteristics of the most luminous PNe. Methods. We analysed 44 fields observed with MUSE at the VLT, covering a total area of ∼11 kpc2. We find [O III]λ5007 sources using the differential emission line filter (DELF) technique. We identified PNe through spectral classification with the aid of the BPT diagram. The PNLF distance was derived using the maximum likelihood estimation technique. For the more luminous PNe, we also measured their extinction using the Balmer decrement. We estimated the luminosity and effective temperature of the central stars of the luminous PNe based on estimates of the excitation class and the assumption of optically thick nebulae. Results. We identify 107 PNe and derive a most-likely distance modulus (m − M) 0 = 26. 48 − 0.26 + 0.11 $ (m-M)_0 = 26.48^{+0.11}_{-0.26} $ ( d = 1. 98 − 0.23 + 0.10 $ d = 1.98^{+0.10}_{-0.23} $ Mpc). We find that the PNe at the PNLF cutoff exhibit relatively low extinction, with some high-extinction cases caused by local dust lanes. We present the lower limit luminosities and effective temperatures of the central stars for some of the brighter PNe. We also identify a few Type I PNe that come from a young population with progenitor masses > 2.5 M⊙ but do not populate the PNLF cutoff. Conclusions. The spatial resolution and spectral information of MUSE allow precise PN classification and photometry. These capabilities also enable us to resolve possible contamination by diffuse gas and dust, improving the accuracy of the PNLF distance to NGC 300. [ABSTRACT FROM AUTHOR]

The article is a foreword for the "Scientific Detector Workshop 2022" (SDW2022) held in Potsdam, Germany. The workshop aims to facilitate the exchange of information about high-performance visible and infrared detectors and systems, with a focus on their application in astronomy. The success of the workshop is demonstrated by the participation of colleagues from observatories, laboratories, and industry worldwide. The article expresses gratitude to the organizers, sponsors, and attendees for their contributions and announces that the next workshop will be hosted by the Australian National University in Canberra in 2025. [Extracted from the article]