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1. Confocal LiDAR for remote high-resolution imaging of auto-fluorescence in aquatic media

Author

Joaquim Santos, Peter John Rodrigo, Paul Michael Petersen, and Christian Pedersen

Subjects
Medicine, Science
Abstract

Abstract Spatially resolved in situ monitoring of plankton can provide insights on the impacts of climate change on aquatic ecosystems due to their vital role in the biological carbon pump. However, high-resolution underwater imaging is technically complex and restricted to small close-range volumes with current techniques. Here, we report a novel inelastic scanning confocal light detection and ranging (LiDAR) system for remote underwater volumetric imaging of fluorescent objects. A continuous wave excitation beam is combined with a pinhole in a conjugated detection plane to reject out-of-focus scattering and accomplish near-diffraction limited probe volumes. The combination of bi-directional scanning with remote focusing enables the acquisition of three-dimensional data. We experimentally determine the point spread and axial weighting functions, and demonstrate selective volumetric imaging of obstructed layers through spatial filtering. Finally, we spatially resolve in vivo autofluorescence from sub-millimeter Acocyclops royi copepods to demonstrate the applicability of our novel instrument in non-intrusive morphological and spectroscopic studies of aquatic fauna. The proposed system constitutes a unique tool e.g. for profiling chlorophyll distributions and for quantitative studies of zooplankton with reduced interference from intervening scatterers in the water column that degrade the the performance of conventional imaging systems currently in place.

Published
2023
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2. Near-critical spreading of droplets

Author

Raphael Saiseau, Christian Pedersen, Anwar Benjana, Andreas Carlson, Ulysse Delabre, Thomas Salez, and Jean-Pierre Delville

Subjects
Science
Abstract

Tanner’s law describes the spreading dynamics of droplets made of Newtonian viscous fluids. Here, the authors demonstrate that this law remains valid for phase-separated binary liquids close to their critical point, and thus for all the associated universality class.

Published
2022
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3. Equivalent Circuit and Continuum Modeling of the Impedance of Electrolyte-Filled Pores

Author

Christian Pedersen, Timur Aslyamov, and Mathijs Janssen

Subjects
Production of electric energy or power. Powerplants. Central stations, TK1001-1841, Renewable energy sources, TJ807-830
Abstract

Batteries, supercapacitors, and several other electrochemical devices charge by accumulating ions in the pores of electrolyte-immersed porous electrodes. The charging of such devices has long been interpreted using equivalent circuits and the partial differential equations these give rise to. Here, we discuss the validity of the transmission line (TL) circuit and equation for modeling a single electrolyte-filled pore in contact with a reservoir of resistance R_{r}. The textbook derivation of the pore-reservoir impedance, R_{r}+Z_{p}, from the TL equation does not correctly account for ionic current conservation at the pore-reservoir interface. However, correcting this shortcoming leads to the same impedance. We also show that the pore impedance, Z_{p}, can be derived directly from the TL circuit, bypassing the TL equation completely. The TL circuit assumes equipotential lines in an electrolyte-filled pore to be straight, which is not the case near the pore entrance and end. To determine the importance of these regions, we numerically simulated the charging of pores of different lengths, ℓ_{p}, and radii, ϱ_{p}, through the Poisson-Nernst-Planck equations. We find that pores with aspect ratios beyond ℓ_{p}/ϱ_{p}⪆5 have impedances in good agreement with Z_{p}.

Published
2023
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4. Large herbivores facilitate the persistence of rare taxa under tundra warming

Author

Eric Post, Christian Pedersen, and David A. Watts

Subjects
Medicine, Science
Abstract

Abstract Ecological rarity, characterized by low abundance or limited distribution, is typical of most species, yet our understanding of what factors contribute to the persistence of rare species remains limited. Consequently, little is also known about whether rare species might respond differently than common species to direct (e.g., abiotic) and indirect (e.g., biotic) effects of climate change. We investigated the effects of warming and exclusion of large herbivores on 14 tundra taxa, three of which were common and 11 of which were rare, at an inland, low-arctic study site near Kangerlussuaq, Greenland. Across all taxa, pooled commonness was reduced by experimental warming, and more strongly under herbivore exclusion than under herbivory. However, taxon-specific analyses revealed that although warming elicited variable effects on commonness, herbivore exclusion disproportionately reduced the commonness of rare taxa. Over the 15-year duration of the experiment, we also observed trends in commonness and rarity under all treatments through time. Sitewide commonness increased for two common taxa, the deciduous shrubs Betula nana and Salix glauca, and declined in six other taxa, all of which were rare. Rates of increase or decline in commonness (i.e., temporal trends over the duration of the experiment) were strongly related to baseline commonness of taxa early in the experiment under all treatments except warming with grazing. Hence, commonness itself may be a strong predictor of species’ responses to climate change in the arctic tundra biome, but large herbivores may mediate such responses in rare taxa, perhaps facilitating their persistence.

Published
2022
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5. Toward Machine-learning-based Metastudies: Applications to Cosmological Parameters

Author

Tom Crossland, Pontus Stenetorp, Daisuke Kawata, Sebastian Riedel, Thomas D. Kitching, Anurag Deshpande, Tom Kimpson, Choong Ling Liew-Cain, Christian Pedersen, Davide Piras, and Monu Sharma

Subjects
Astronomy data analysis, Cosmological parameters, Astronomy databases, Astrophysics, QB460-466
Abstract

We develop a new model for automatic extraction of reported measurement values from the astrophysical literature, utilizing modern natural language processing techniques. We use this model to extract measurements present in the abstracts of the approximately 248,000 astrophysics articles from the arXiv repository, yielding a database containing over 231,000 astrophysical numerical measurements. Furthermore, we present an online interface ( Numerical Atlas ) to allow users to query and explore this database, based on parameter names and symbolic representations, and download the resulting data sets for their own research uses. To illustrate potential use cases, we then collect values for nine different cosmological parameters using this tool. From these results, we can clearly observe the historical trends in the reported values of these quantities over the past two decades and see the impacts of landmark publications on our understanding of cosmology.

Published
2023
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6. Compressing the Cosmological Information in One-dimensional Correlations of the Lyman-α Forest

Author

Christian Pedersen, Andreu Font-Ribera, and Nickolay Y. Gnedin

Subjects
Cosmology, Lyman alpha forest, Astronomy data reduction, Large-scale structure of the universe, Astrophysics, QB460-466
Abstract

Observations of the Lyman- α forest from spectroscopic surveys such as the Baryon Oscillation Spectroscopic Survey or its extension, eBOSS, or the ongoing Dark Energy Spectroscopic Instrument (DESI) survey offer a unique window to study the growth of structure on megaparsec scales. Interpretation of these measurements is a complicated task, requiring hydrodynamical simulations to model and marginalize over the thermal and ionization state of the intergalactic medium. This complexity has limited the use of Ly α clustering measurements in joint cosmological analyses. In this work we show that the cosmological information content of the one-dimensional power spectrum ( P _1D ) of the Lyman- α forest can be compressed into a simple two-parameter likelihood without any significant loss of constraining power. We simulate P _1D measurements from DESI using hydrodynamical simulations and show that the compressed likelihood is model independent and lossless, recovering unbiased results even in the presence of massive neutrinos or running of the primordial power spectrum.

Published
2023
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7. A Tunable Hyperspectral Imager for Detection and Quantification of Marine Biofouling on Coated Surfaces

Author

Joaquim Santos, Morten Lysdahlgaard Pedersen, Burak Ulusoy, Claus Erik Weinell, Henrik Chresten Pedersen, Paul Michael Petersen, Kim Dam-Johansen, and Christian Pedersen

Subjects
hyperspectral imaging, biofouling, spectral library, classification, fouling control coatings, led illumination, Chemical technology, TP1-1185
Abstract

Fouling control coatings (FCCs) are used to prevent the accumulation of marine biofouling on, e.g., ship hulls, which causes increased fuel consumption and the global spread of non-indigenous species. The standards for performance evaluations of FCCs rely on visual inspections, which induce a degree of subjectivity. The use of RGB images for objective evaluations has already received interest from several authors, but the limited acquired information restricts detailed analyses class-wise. This study demonstrates that hyperspectral imaging (HSI) expands the specificity of biofouling assessments of FCCs by capturing distinguishing spectral features. We developed a staring-type hyperspectral imager using a liquid crystal tunable filter as the wavelength selective element. A novel light-emitting diode illumination system with high and uniform irradiance was designed to compensate for the low-filter transmittance. A spectral library was created from reflectance-calibrated optical signatures of representative biofouling species and coated panels. We trained a neural network on the annotated library to assign a class to each pixel. The model was evaluated on an artificially generated target, and global accuracy of 95% was estimated. The classifier was tested on coated panels (exposed at the CoaST Maritime Test Centre) with visible intergrown biofouling. The segmentation results were used to determine the coverage percentage per class. Although a detailed taxonomic description might be complex due to spectral similarities among groups, these results demonstrate the feasibility of HSI for repeatable and quantifiable biofouling detection on coated surfaces.

Published
2022
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8. Unusual late July observation of a fledgling Lapland longspur in low Arctic Greenland following the cool spring of 2018

Author

Eric Post, Eva Beyen, Pernille Sporon Bøving, R. Conor Higgins, Christian John, Jeff Kerby, Christian Pedersen, and David A. Watts

Subjects
arctic, phenology, nesting, climate, warming, green-up timing, Environmental sciences, GE1-350, Environmental engineering, TA170-171
Abstract

We report an observation of a flightless fledgling Lapland longspur (Calcarius lapponicus (Linnaeus, 1758)) at a long-term study site near Kangerlussuaq, Greenland, in late July 2018. Based on our observations of longspur nests at the site dating back to 1993, we estimate that the fledgling observed in 2018 may have originated from a nest initiated 12–37 d later than nesting in previous years. Onset of spring in 2018 was late, but comparable with other years in which longspur nests were observed a full calendar month earlier than in 2018. An analysis including multiple candidate predictor variables revealed a strong negative association between estimated longspur nest initiation dates and mean May temperature, as well as a weaker association with the length of the annual period of vegetation green up at the site. Given the limitations of our data, however, we are unable to assign causality to the 2018 observation, and cannot rule out other possibilities, such as that it may have resulted from a second clutch.

Published
2019
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9. Cellular, circuit and transcriptional framework for modulation of itch in the central amygdala

Author

Vijay K Samineni, Jose G Grajales-Reyes, Gary E Grajales-Reyes, Eric Tycksen, Bryan A Copits, Christian Pedersen, Edem S Ankudey, Julian N Sackey, Sienna B Sewell, Michael R Bruchas, and Robert W Gereau

Subjects
itch, central amygdala, pain, anxiety, affect, RNAseq, Medicine, Science, Biology (General), QH301-705.5
Abstract

Itch is an unpleasant sensation that elicits robust scratching and aversive experience. However, the identity of the cells and neural circuits that organize this information remains elusive. Here, we show the necessity and sufficiency of chloroquine-activated neurons in the central amygdala (CeA) for both itch sensation and associated aversion. Further, we show that chloroquine-activated CeA neurons play important roles in itch-related comorbidities, including anxiety-like behaviors, but not in some aversive and appetitive behaviors previously ascribed to CeA neurons. RNA-sequencing of chloroquine-activated CeA neurons identified several differentially expressed genes as well as potential key signaling pathways in regulating pruritis. Finally, viral tracing experiments demonstrate that these neurons send projections to the ventral periaqueductal gray that are critical in modulation of itch. These findings reveal a cellular and circuit signature of CeA neurons orchestrating behavioral and affective responses to pruritus in mice.

Published
2021
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10. Cold-induced hyperphagia requires AgRP neuron activation in mice

Author

Jennifer D Deem, Chelsea L Faber, Christian Pedersen, Bao Anh Phan, Sarah A Larsen, Kayoko Ogimoto, Jarrell T Nelson, Vincent Damian, Megan A Tran, Richard D Palmiter, Karl J Kaiyala, Jarrad M Scarlett, Michael R Bruchas, Michael W Schwartz, and Gregory J Morton

Subjects
agouti-related peptide, body temperature, hyperphagia, thermoregulation, energy intake, fiber photometry, Medicine, Science, Biology (General), QH301-705.5
Abstract

To maintain energy homeostasis during cold exposure, the increased energy demands of thermogenesis must be counterbalanced by increased energy intake. To investigate the neurobiological mechanisms underlying this cold-induced hyperphagia, we asked whether agouti-related peptide (AgRP) neurons are activated when animals are placed in a cold environment and, if so, whether this response is required for the associated hyperphagia. We report that AgRP neuron activation occurs rapidly upon acute cold exposure, as do increases of both energy expenditure and energy intake, suggesting the mere perception of cold is sufficient to engage each of these responses. We further report that silencing of AgRP neurons selectively blocks the effect of cold exposure to increase food intake but has no effect on energy expenditure. Together, these findings establish a physiologically important role for AgRP neurons in the hyperphagic response to cold exposure.

Published
2020
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11. CW Direct Detection Lidar with a Large Dynamic Range of Wind Speed Sensing in a Remote and Spatially Confined Volume

Author

Lichun Meng, Christian Pedersen, and Peter John Rodrigo

Subjects
Doppler wind lidar, direct detection lidar, scanning Fabry–Perot interferometer, wind sensing, spatial weighting function, continuous-wave lidar, Science
Abstract

A novel continuous-wave (CW) direct detection lidar (DDL) is demonstrated to be capable of wind speed measurement 40 m away with an update rate of 4 Hz using a fiber-based scanning Fabry–Perot interferometer as an optical frequency discriminator. The proposed CW DDL has a large dynamic wind speed range with no sign ambiguity and its sensitivity is assessed by comparing its performance with that of a CW coherent detection lidar (CDL) in a side-by-side wind measurement. A theoretical model of the spatial weighting function of the fiber-based CW DDL is also presented and validated experimentally. This work shows that the CW DDL has a spatially confined measurement volume with a Lorentzian axial profile similar to that of a CW CDL. The proposed DDL has potential use in various applications in which requirements such as high-speed wind sensing and directional discrimination are not met by state-of-the-art Doppler wind lidar systems.

Published
2021
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12. Capillary deformation of ultrathin glassy polymer films by air nanobubbles

Author

Shuai Ren, Christian Pedersen, Andreas Carlson, Thomas Salez, and Yuliang Wang

Subjects
Physics, QC1-999
Abstract

Confined glasses and their anomalous interfacial rheology raise important questions in fundamental research and numerous practical applications. In this work, we study the influence of interfacial air nanobubbles on the free surface of ultrathin high-molecular-weight glassy polystyrene films immersed in water, in ambient conditions. In particular, we reveal the counterintuitive fact that a soft nanobubble is able to deform the surface of a rigid glass, forming a nanocrater with a depth that increases with time. By combining in situ atomic-force-microscopy measurements and a modified lubrication model for the liquidlike layer at the free surface of the glass, we demonstrate that the capillary pressure in the nanobubble together with the liquidlike layer at the free surface of the glass determine the spatiotemporal growth of the nanocraters. Finally, from the excellent agreement between the experimental profiles and the numerical solutions of the governing glassy thin-film equation, we are able to precisely extract the surface mobility of the glass. In addition to revealing and quantifying how surface nanobubbles deform immersed glasses, until the latter eventually dewet from their substrates, our work provides a novel, precise, and simple measurement of the surface nanorheology of glasses.

Published
2020
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13. Formulation of the microbicide INP0341 for in vivo protection against a vaginal challenge by Chlamydia trachomatis.

Author

Christian Pedersen, Anatoly Slepenkin, Sara B E Andersson, Jonas H Fagerberg, Christel A S Bergström, and Ellena M Peterson

Subjects
Medicine, Science
Abstract

The salicylidene acylhydrazide (SA) compounds have exhibited promising microbicidal properties. Previous reports have shown the SA compounds, using cell cultures, to exhibit activity against Chlamydia trachomatis, herpes simplex virus and HIV-1. In addition, using an animal model of a vaginal infection the SA compound INP0341, when dissolved in a liquid, was able to significantly protect mice from a vaginal infection with C. trachomatis. To expand upon this finding, in this report INP0341 was formulated as a vaginal gel, suitable for use in humans. Gelling agents (polymers) with inherent antimicrobial properties were chosen to maximize the total antimicrobial effect of the gel. In vitro formulation work generated a gel with suitable rheology and sustained drug release. A formulation containing 1 mM INP0341, 1.6 wt% Cremophor ELP (solubility enhancer) and 1.5 wt% poly(acrylic acid) (gelling and antimicrobial agent), was chosen for studies of efficacy and toxicity using a mouse model of a vaginal infection. The gel formulation was able to attenuate a vaginal challenge with C. trachomatis, serovar D. Formulations with and without INP0341 afforded protection, but the inclusion of INP0341 increased the protection. Mouse vaginal tissue treated with the formulation showed no indication of gel toxicity. The lack of toxicity was confirmed by in vitro assays using EpiVaginal tissues, which showed that a 24 h exposure to the gel formulation did not decrease the cell viability or the barrier function of the tissue. Therefore, the gel formulation described here appears to be a promising vaginal microbicide to prevent a C. trachomatis infection with the potential to be expanded to other sexually transmitted diseases.

Published
2014
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15. Synthetic geopolymers for controlled delivery of oxycodone: adjustable and nanostructured porosity enables tunable and sustained drug release.

Author

Johan Forsgren, Christian Pedersen, Maria Strømme, and Håkan Engqvist

Subjects
Medicine, Science
Abstract

In this article we for the first time present a fully synthetic mesoporous geopolymer drug carrier for controlled release of opioids. Nanoparticulate precursor powders with different Al/Si-ratios were synthesized by a sol-gel route and used in the preparation of different geopolymers, which could be structurally tailored by adjusting the Al/Si-ratio and the curing temperatures. In particular, it was shown that the pore sizes of the geopolymers decreased with increasing Al/Si ratio and that completely mesoporous geopolymers could be produced from precursor particles with the Al/Si ratio 2:1. The mesoporosity was shown to be associated with a sustained and linear in vitro release profile of the opioid oxycodone. A clinically relevant release period of about 12 h was obtained by adjusting the size of the pellets. The easily fabricated and tunable geopolymers presented in this study constitute a novel approach in the development of controlled release formulations, not only for opioids, but whenever the clinical indication is best treated with a constant supply of drugs and when the mechanical stability of the delivery vehicle is crucial.

Published
2011
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16. Surface transition on ice induced by the formation of a grain boundary.

Author

Christian Pedersen, Albert Mihranyan, and Maria Strømme

Subjects
Medicine, Science
Abstract

Interfaces between individual ice crystals, usually referred to as grain boundaries, play an important part in many processes in nature. Grain boundary properties are, for example, governing the sintering processes in snow and ice which transform a snowpack into a glacier. In the case of snow sintering, it has been assumed that there are no variations in surface roughness and surface melting, when considering the ice-air interface of an individual crystal. In contrast to that assumption, the present work suggests that there is an increased probability of molecular surface disorder in the vicinity of a grain boundary. The conclusion is based on the first detailed visualization of the formation of an ice grain boundary. The visualization is enabled by studying ice crystals growing into contact, at temperatures between -20°C and -15°C and pressures of 1-2 Torr, using Environmental Scanning Electron Microscopy. It is observed that the formation of a grain boundary induces a surface transition on the facets in contact. The transition does not propagate across facet edges. The surface transition is interpreted as the spreading of crystal dislocations away from the grain boundary. The observation constitutes a qualitatively new finding, and can potentially increase the understanding of specific processes in nature where ice grain boundaries are involved.

Published
2011
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20. PET/MRI Applications in Pediatric Epilepsy

Author

Christian Pedersen, Mariam Aboian, Steven A. Messina, Heike Daldrup-Link, and Ana M. Franceschi

Abstract

Epilepsy neuroimaging assessment requires exceptional anatomic detail, physiologic and metabolic information. Magnetic resonance (MR) protocols are often time-consuming necessitating sedation and positron emission tomography (PET)/computed tomography (CT) comes with a significant radiation dose. Hybrid PET/MRI protocols allow for exquisite assessment of brain anatomy and structural abnormalities, in addition to metabolic information in a single, convenient imaging session, which limits radiation dose, sedation time, and sedation events. Brain PET/MRI has proven especially useful for accurate localization of epileptogenic zones in pediatric seizure cases, providing critical additional information and guiding surgical decision making in medically refractory cases. Accurate localization of seizure focus is necessary to limit the extent of the surgical resection, preserve healthy brain tissue, and achieve seizure control. This review provides a systematic overview with illustrative examples demonstrating the applications and diagnostic utility of PET/MRI in pediatric epilepsy.

Published
2023

23. Utilizing 3D DOSY NMR in the characterization of organic compounds in coal chemical wastewater

Author

Shiyu Jia, Xianglin Hou, Christian Pedersen, Qi Zhao, Bin Yuan, Hui Ma, and Yingxiong Wang

Subjects
Wastewater, Environmental remediation, business.industry, Chemistry, Physical separation, Coal, Biochemical engineering, business, Oxygenate, Characterization (materials science)
Abstract

Coal chemical wastewater (CCW) with the features of high toxicity and poor biodegradability is a big issue in environmental remediation, posing a great threat to aquatic ecosystems and to human beings. Such complex molecular mixtures are notoriously difficult to characterize without initial physical separation. Herein, we present the 3D diffusion ordered spectroscopy (DOSY) analysis for CCW using DOSY-COSY and DOSY-HSQC methods, the advantages of this strategy have been demonstrated in the analysis of mixtures of aliphatic oxygenates and aromatic compounds, before being implemented on a genuine CCW sample in this study. The results showed that 3D DOSY is a robust and reliable tool for providing superior resolution and virtual separation of complex pollutants, and can be used as a general approach for structural elucidation.

Published
2022

24. Supercontinuum Applications in High Resolution Non-Invasive Optical Imaging.

Author

Adrian Gh. Podoleanu, Ole Bang, Ajanta Barh, Sophie Bojesen, Magalie Bondu, Adrian Bradu, Sophie Caujolle, Catherine Chin, Mark Denninger, Thomas Feuchter, Felix Fleischhauer, Merete Hædersdal, Günther Hannesschläger, Niels Møller Israelsen, Deepak Jain, Mikkel Jensen, Ivan B. Gonzalo, Michael Maria, Manuel Marques, Lasse Leick, Peter Tidemand-Lichtenberg, Mette Mogensen, Peter M. Moselund, Christian Pedersen, and Christian R. Petersen

Published
2019
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25. Technology generation to dissemination: lessons learned from the tef improvement project

Author

Suhail Rafudeen, Muluneh Tamiru, Zerihun Tadele, Mike Robinson, Kidu Gebremeskel, Wuyan Wang, Brikti Ferede, Regula Blösch, Abiel Rindisbacher, Korinna Esfeld, Shimelis Hussein, Ermias Abate, Sonia Plaza-Wüthrich, Firew Mekbib, Ian Barker, Victoria Johnson-Chadwick, Dominik Klauser, Habte Jifar, Gina Cannarozzi, Worku Kebede, Yazachew Genet, Samuel C. Zeeman, Abate Bekele, Hans Christian Pedersen, Kebebew Assefa, Moritz Jöst, Naomi Nakayama, Negussu Husein, Solomon Chanyalew, Annett Weichert, Federico Martinelli, Rizqah Kamies, Kidist Tolosa, Cannarozzi, Gina, Chanyalew, Solomon, Assefa, Kebebew, Bekele, Abate, Blösch, Regula, Weichert, Annett, Klauser, Dominik, Plaza-Wüthrich, Sonia, Esfeld, Korinna, Jöst, Moritz, Rindisbacher, Abiel, Jifar, Habte, Johnson-Chadwick, Victoria, Abate, Ermia, Wang, Wuyan, Kamies, Rizqah, Husein, Negussu, Kebede, Worku, Tolosa, Kidist, Genet, Yazachew, Gebremeskel, Kidu, Ferede, Brikti, Mekbib, Firew, Martinelli, Federico, Pedersen, Hans Christian, Rafudeen, Suhail, Hussein, Shimeli, Tamiru, Muluneh, Nakayama, Naomi, Robinson, Mike, Barker, Ian, Zeeman, Samuel, and Tadele, Zerihun

Subjects
0106 biological sciences, 0301 basic medicine, TILLING, Context (language use), Plant Science, Biology, 580 Plants (Botany), Horticulture, Eragrostis tef, 01 natural sciences, Farmer-participatory research, Indigenous, 03 medical and health sciences, Genetic, Orphan crop, Settore AGR/07 - Genetica Agraria, Marker-assisted breeding, Orphan crops, Tef, Milestone (project management), Genetics, Population growth, Environmental planning, Uncategorized, Food security, business.industry, 030104 developmental biology, Agriculture, Famine, business, Green Revolution, Agronomy and Crop Science, 010606 plant biology & botany
Abstract

Indigenous crops also known as orphan crops are key contributors to food security, which is becoming increasingly vulnerable with the current trend of population growth and climate change. They have the major advantage that they fit well into the general socio-economic and ecological context of developing world agriculture. However, most indigenous crops did not benefit from the Green Revolution, which dramatically increased the yield of major crops such as wheat and rice. Here, we describe the Tef Improvement Project, which employs both conventional- and molecular-breeding techniques to improve tef—an orphan crop important to the food security in the Horn of Africa, a region of the world with recurring devastating famines. We have established an efficient pipeline to bring improved tef lines from the laboratory to the farmers of Ethiopia. Of critical importance to the long-term success of this project is the cooperation among participants in Ethiopia and Switzerland, including donors, policy makers, research institutions, and farmers. Together, European and African scientists have developed a pipeline using breeding and genomic tools to improve the orphan crop tef and bring new cultivars to the farmers in Ethiopia. We highlight a new variety, Tesfa, developed in this pipeline and possessing a novel and desirable combination of traits. Tesfa’s recent approval for release illustrates the success of the project and marks a milestone as it is the first variety (of many in the pipeline) to be released., Euphytica, 214 (2), ISSN:0014-2336, ISSN:1573-5060

Published
2023
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26. Surface and Bulk Relaxation of Vapour-Deposited Polystyrene Glasses

Author

Junjie Yin, Christian Pedersen, Michael F. Thees, Andreas Carlson, Thomas Salez, James A. Forrest, University of Waterloo [Waterloo], University of Oslo (UiO), Laboratoire Ondes et Matière d'Aquitaine (LOMA), Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS), Natural Sciences and Research Council of Canada, ANR-21-ERCC-0010,EMetBrown,Mouvement brownien au voisinage d'interfaces molles(2021), ANR-21-CE06-0029,SOFTER,Capteur Interférométrique de Contraintes de Surface(2021), ANR-21-CE06-0039,FRICOLAS,Frottements dans les systèmes complexes(2021), and European Project: ERC CoG 101039103,EMetBrown

Subjects
[PHYS.PHYS.PHYS-FLU-DYN]Physics [physics]/Physics [physics]/Fluid Dynamics [physics.flu-dyn], Condensed Matter - Materials Science, Fluid Dynamics (physics.flu-dyn), General Physics and Astronomy, Materials Science (cond-mat.mtrl-sci), Classical Physics (physics.class-ph), FOS: Physical sciences, Physics - Classical Physics, Physics - Fluid Dynamics, Condensed Matter - Soft Condensed Matter, [PHYS.MECA.MEMA]Physics [physics]/Mechanics [physics]/Mechanics of materials [physics.class-ph], [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Soft Condensed Matter (cond-mat.soft), [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph], Physical and Theoretical Chemistry, [PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft]
Abstract

International audience; We have studied the liquid-like response of the surface of vapour-deposited glassy films of polystyrene to the introduction of gold nanoparticles on the surface. The build-up of polymer material was measured as a function of time and temperature for both as-deposited films, as well as films that have been rejuvenated to become normal glasses cooled from the equilibrium liquid. The temporal evolution of the surface profile is well described by the characteristic power law of capillary-driven surface flows. In all cases, the surface evolution of the as-deposited films and the rejuvenated films are enhanced compared to bulk and are not easily distinguishable from each other. The temperature dependence of the measured relaxation times determined from the surface evolution is found to be quantitatively comparable to similar studies for high molecular weight spincast polystyrene. Comparisons to numerical solutions of the glassy thin film equation provide quantitative estimates of the surface mobility. For temperatures sufficiently close to the glass-transition temperature, particle embedding is also measured and used as a probe of bulk dynamics, and in particular bulk viscosity.

Published
2023

28. Tunable infrared upconversion module for the 1.9 to 5.5 µm range

Author

Peter Tidemand-Lichtenberg, Martin Aagaard, A. S. Ashik, Christian Pedersen, and Brian Julsgaard

Subjects
Atomic and Molecular Physics, and Optics
Abstract

In this Letter, an efficient tunable upconversion module is demonstrated and characterized. The module combines high conversion efficiency and low noise with broad continuous tuning, covering the spectroscopically important range from 1.9 to 5.5 µm. A fully computer-controlled, compact, portable system is presented and characterized in terms of efficiency, spectral coverage, and bandwidth, using simple globar illumination. The upconverted signal is in the 700–900 nm range, ideal for Si-based detection systems. The output from the upconversion module is fiber coupled, enabling flexible connection to commercial NIR detectors or NIR spectrometers. In order to cover the spectral range of interest using periodically poled LiNbO3 as the nonlinear material, poling periods ranging from 15 to 23.5 µm are needed. The full spectral coverage is reached using a stack of four fanned poled crystals, enabling maximal upconversion efficiency of any spectral signature of interest in the 1.9 to 5.5 µm range.

Published
2022

29. Silylated Sugars – Synthesis and Properties

Author

Christian Pedersen, Mikael Bols, Martin Jæger Pedersen, and Tobias Gylling Frihed

Subjects
chemistry.chemical_classification, chemistry.chemical_compound, Glycosylation, chemistry, Silylation, Stereochemistry, Carbohydrate chemistry, Organic Chemistry, Glycoside, Molecule, Reactivity (chemistry), Glycosyl, Selectivity
Abstract

Silicon has been used in carbohydrate chemistry for half a century, but mostly as a protective group for sugar alcohols. Recently, the use of silicon has expanded to functionalization via C–H activation, conformational arming of glycosyl donors, and conformational alteration of carbohydrates. Silicon has proven useful as more than a protective group and during the last one and a half decades we have demonstrated how it influences both the reactivity of glycosyl donors and stereochemical outcome of glycosylations. Silicon can also be attached directly to the sugar C-backbone, which has even more pronounced effects on the chemistry and properties of the molecules. In this Account, we will give a tour through our work involving silicon and carbohydrates.1 Introduction2 Conformational Arming of Glycosyl Donors with Silyl Groups3 Silyl Protective Groups for Tethering Glycosyl Donors4. Si–C Glycosides via C–H Activation4.1 C–H Activation and Oxidation of Methyl 6-Deoxy-l-glycosides4.2 Synthesis of All Eight 6-Deoxy-l-sugars4.3 Synthesis of All Eight l-Sugars by C–H Activation4.4 Modification of the Oxasilolane Ring5 C–Si in Glycosyl Donors – Activating or Not?6 Si–C-Substituted Pyranosides7 Perspective

Published
2021

30. Erratum: Searches for continuous gravitational waves from 15 supernova remnants and fomalhaut b with advanced LIGO (2019, ApJ, 875, 122)*

Author

A. Parida, S. S. Eikenberry, F. Frasconi, Chris A. Collins, R. Flaminio, Marcus E. Lower, Rosa Poggiani, V. Frey, E. K. Wessel, Nikhil Sarin, Odylio D. Aguiar, I. W. Martin, S. Farinon, P. Raffai, Andrew Matas, C. F. Da Silva Costa, M. A. Okada, G. Rutins, Graham Woan, Sebastiano Bernuzzi, D. Passuello, A. Cirone, H. S. Chen, Hyun Lee, J. D. Lough, K. Mason, S. A. Bilgili, E. C. Ferreira, Robert L. Byer, J. Calderón Bustillo, Sanjeev Dhurandhar, O. Halim, N. A. Robertson, Stuart Reid, F. J. Hayes, Patrick Godwin, N. Sennett, P. Kumar, Jacob Scheuer, B. R. Hall, J. Hanks, R. M. Martin, David A. Nichols, Edward K. Porter, J. G. Bartlett, Márton Tápai, K. W. Tsang, C. Horst, W. A. Campbell, Andreas Freise, C. V. Kalaghatgi, M. Rakhmanov, G. Pagano, Paul D. Lasky, J. W. Westhouse, M. C. Araya, Srishti Tiwari, C. Lazzaro, Patricia Schmidt, V. Brisson, Bernard F. Schutz, Li Ju, Matthew Pitkin, D. Cohen, Kiran Prasai, P. J. Veitch, S. A. Usman, C. Messenger, Liam Cunningham, E. A. M. Muniz, Daniel A. Shaddock, P. Gruning, Brittany Kamai, Riccardo Ciolfi, Alberto Vecchio, Geoffrey Mo, J. M. Fishner, Roman Schnabel, J. Hanson, M. Wade, M. Montani, P. Sharma, Héctor Estellés, N. Letendre, F. Ricci, A. Lenon, J. E. Brau, A. A. van Veggel, Richard Gray, Efim A. Khazanov, Peter T. H. Pang, C. Affeldt, G. Ballardin, Moritz Mehmet, A. A. Ciobanu, M. Granata, Minchuan Zhou, F. Marion, P. Brockill, Nancy Aggarwal, Hang Yu, P. G. Murray, Fabien Kéfélian, J. H. Hough, P. W. F. Forsyth, S. R. Thondapu, J. R. Palamos, Michele Zanolin, S. Mukherjee, T. J. Massinger, T. Vo, V. Kalogera, N. Leroy, G. D. Hammond, Javed Rana, H. Fong, G. Greco, M. Haney, T. A. Callister, Alec Mishkin, R. Cavalieri, S. R. P. Mohapatra, G. Giordano, K. Toland, A. K. Srivastava, A. E. Pace, H. Ohta, Vuk Mandic, B. Bécsy, M. Kasprzack, I. Dave, B. D. Lackey, R. L. Ward, Scott Coughlin, A.J. Weinstein, K. H. Lai, M. Phelps, H. S. Cho, L. Kuo, H. Yamamoto, E. Capocasa, M. Chan, S. Walsh, D. J. McManus, A. Schönbeck, B. Rajbhandari, Andrew Mehta, S. D. Linker, R. Robie, M. Fletcher, B. Hughey, R. D. Kennedy, José A. Font, Gregorio Carullo, S. Kumar, J. Prasad, H. K. Gulati, V. Raymond, Steven Bloemen, H. J. Bulten, Shiuh Chao, P. J. Sutton, N. Singh, C. Buy, Samuele Cortese, J. McIver, Vivishek Sudhir, P. A. Altin, A. Basti, N. A. Lockerbie, E. Schreiber, Charalampos Markakis, P. Grassia, Kipp Cannon, M. Steinke, P.H. Nguyen, Ryan N. Lang, Z. Doctor, Alyssa Garcia, J. H. Romie, Carlos O. Lousto, S. Sitmukhambetov, Alejandro Torres-Forné, A. Samajdar, D. M. Wysocki, T. Mistry, Mark A. Scheel, Charlie Hoy, F. Clara, M. A. Aloy, T. M. Evans, C. North, Thomas Dent, P. Corban, P. Ajith, B. Mours, Mandar Patil, Abhirup Ghosh, J. Neilson, Bala R. Iyer, Y. K. Lecoeuche, M. Muratore, Karsten Danzmann, Fabrizio Barone, N. Mukund, P. B. Covas, M. C. Edwards, T. Hinderer, Marta Colleoni, J. A. Giaime, Michael Pürrer, R. Pedurand, Benno Willke, A. Grado, D. C. Vander-Hyde, S. S. Y. Chua, J. Eichholz, J.-P. Coulon, Hua Wang, E. A. Chase, J. Betzwieser, G. Kang, L. R. Cominsky, O. A. Hannuksela, Z. Frei, A. Pal-Singh, S. Caride, Kevin Barkett, N. Bode, S. E. Gossan, Tristan Briant, R. Gustafson, Antoine Heidmann, Rana X. Adhikari, S. McCormick, C. Casentini, Slawomir Gras, D. Töyrä, H. Overmier, S. W. S. Ng, G. Wang, M. C. Heintze, J. S. Areeda, I. Belahcene, B. B. Lane, N. Mazumder, Maher Yazback, F. Donovan, J. Bosveld, N. A. Holland, N. V. Keerthana, M.L. Walker, C. Cahillane, L. Sun, M. C. Milovich-Goff, Dániel Barta, J. D. E. Creighton, V. Gayathri, P. Puppo, J.-D. Fournier, S. J. Kapadia, A. L. Stuver, A. S. Sengupta, H. W. Lee, I. Di Palma, S. T. Countryman, Francesco Pannarale, E. A. Huerta, J. L. Wright, Alessandra Corsi, B. W. Schulte, A. Rocchi, J. P. Zendri, R. Kashyap, Chandra Kant Mishra, R. Bhandare, Sylvain Marsat, Lee McCuller, T. Bulik, T. D. Abbott, O. Puncken, J. M. Gonzalez Castro, Philip F. Hopkins, C. Cocchieri, B. Goncharov, R. Birney, M. Kinley-Hanlon, I. Fiori, Shawn Rosofsky, Jun Liu, S. Raja, S. E. Strigin, D. Sellers, J. Meidam, Jeff R. Powell, Riccardo Sturani, D. Hoak, Stefan L. Danilishin, Patrick Brady, L. Matone, Haocun Yu, M. Landry, R. M. S. Schofield, Surabhi Sachdev, Christopher J. Moore, V. Avendano, R. Mittleman, Nelson Christensen, Geoffrey Lovelace, Soichiro Morisaki, John Worden, P. Couvares, Carl-Johan Haster, O. J. Piccinni, L. Rolland, C. L. Romel, Miriam Cabero, Alessandra Buonanno, L. Wallace, S. Biscoveanu, M. B. Shaner, Benjamin J. Owen, Alexander Urban, Antoni Ramos-Buades, V. V. Frolov, A. Singhal, F. Carbognani, Jordan Camp, R. L. Savage, A. S. Bell, M. Laxen, Anchal Gupta, A. Królak, B. D. Cheeseboro, G. Cerretani, P. J. Easter, J. F. J. van den Brand, M. J. Szczepańczyk, L. Di Fiore, E. Bonilla, S. Sunil, M. Tacca, Jessica Steinlechner, A. Neunzert, P.-F. Cohadon, M. Heurs, Irina Kowalska, E. Katsavounidis, Xiuling Li, C. I. Torrie, Jan Harms, Kazuhiro Agatsuma, Kin Sing Stephen Lee, Frank Ohme, M. Tonelli, R. De Rosa, Kwan-Lok Li, I. Nardecchia, Reed Essick, Martin Hendry, Cecilio García-Quirós, S. Kandhasamy, M. Fishbach, B. Sorazu, Christopher Wipf, Archisman Ghosh, A. P. Lundgren, Gabrielle Allen, E. J. Daw, M. Punturo, F. Garufi, Antonio Marquina, Surendra Nadh Somala, I. Dorrington, Robert J. McCarthy, T. A. Ferreira, R. Frey, Joseph Smith, S. Brunett, J. Zweizig, A. W. Heptonstall, E. L. Merilh, D. Barker, K. D. Giardina, Denis Martynov, Marco Bazzan, C. Ingram, L. Pinard, L. Naticchioni, Salvatore Vitale, R. Kirchhoff, B. L. Pearlstone, N. Man, Antonios Kontos, D. Moffa, J. J. McCann, J.-M. Isac, D. Hofman, Linqing Wen, A. Bisht, A. Kutynia, M. A. Page, Tyson Littenberg, Z. Tornasi, Junwei Cao, Sebastian Steinlechner, T. J. Slaven-Blair, S. ShyamSundar, C. Stachie, Hongyu Shen, O. de Varona, J. B. Kanner, Federico Ferrini, Lijing Shao, G. Vajente, S. M. Gaebel, Christopher P. L. Berry, S. H. Huttner, G. M. Harry, Andrea Chincarini, K. Venkateswara, Yuri Levin, C. Austin, C.D. Booth, M. Barsuglia, S. Appert, A. Giazotto, P. Shawhan, I. Ferrante, T. Z. Summerscales, A. Viceré, T. Huynh-Dinh, Fabio Hernandez, H. Cao, Ashok Kumar, D. J. Vine, W. Katzman, Alena Ananyeva, D. C. Coyne, Stanislav Babak, Rico K. L. Lo, Kendall Ackley, R. K. Nayak, F. Y. Khalili, Ken K. Y. Ng, A. Hreibi, M. Thomas, D. Fiorucci, Manuela Rizzo, H. Radkins, A. Bozzi, A. K. Prajapati, A. R. Wade, M. Agathos, M. Brinkmann, R. Quitzow-James, N. N. Janthalur, B. Sassolas, K. Izumi, L. Xiao, J. S. Lange, H. Y. Chia, M. C. Díaz, W. S. Kim, M. H. Wimmer, K. Haughian, S. Hochheim, M. Yvert, M. Nery, Marc Favata, L. E. Wade, Roger Jones, V. J. Roma, A. P. Spencer, G. Kuehn, C. M. Mow-Lowry, Sergey P. Vyatchanin, Andrew Melatos, M. Lorenzini, A. Masserot, M. Khursheed, Ettore Majorana, Robert Stone, Alessandro Nagar, D. D. Brown, Anthony A. Amato, N. van Bakel, Sebastien Biscans, P. Fulda, P. Charlton, F. Magaña-Sandoval, L. Aiello, M. Gosselin, A. R. Williamson, D. Huet, R. Green, M. Was, M. C. Tringali, A. K. Zadrożny, E. E. Cowan, V. Boschi, L. Zhang, J. H. Klika, M. Bawaj, J. Junker, M. van Beuzekom, K. W. Chung, David Coward, T. Hardwick, D. Steinmeyer, F. Travasso, M. Constancio, A. Allocca, Sascha Husa, G. Venugopalan, D.B. DeBra, Mikhail L. Gorodetsky, C. Whittle, Z. Khan, P. Ehrens, Paul M. Ricker, Y. Setyawati, H. Khan, S. E. Barclay, B. F. Whiting, F. Brighenti, C. Talbot, J. H. Briggs, J. Casanueva Diaz, D. H. Reitze, A. F. Brooks, P. J. Quinonez, V. Kringel, J. L. Willis, Ofek Birnholtz, M. F. Carney, P. Schale, R. Bonnand, Mariana Fazio, H. Vocca, C. Van Den Broeck, E. Sowell, Albrecht Rüdiger, Xing-Jiang Zhu, Jochen Kissel, Felice Sorrentino, V. Srivastava, D. Talukder, Michał Bejger, M. Standke, M. Croquette, David A. Williams, A. Effler, I. W. Harry, D. Mukherjee, Y. R. Chen, J. Jiang, Alessandro Bertolini, M. Fays, D. Moraru, J. C. Driggers, Matthew Evans, M. Bitossi, G. Bergmann, K. Wette, M. M. Hanke, Leo Singer, E. Cesarini, M. Hulko, T. D. Creighton, Eugeniy E. Mikhailov, Jörg Hennig, Eric Howell, A. Strunk, G. Vedovato, L. E. H. Datrier, D. B. Kozak, D. Stocks, C. Vorvick, P. Thomas, M. Arène, S. B. Anderson, Tim Dietrich, A. Perreca, G. Gemme, A. Di Lieto, R. A. Eisenstein, S. J. Chamberlin, Jishnu Suresh, G. D. Meadors, Z. A. Warden, R. Gouaty, T. Zelenova, Riccardo Bassiri, John J. Oh, M. Vasúth, Jonathan Cripe, N. Kijbunchoo, E. Cuoco, Sheelu Abraham, K. Kawabe, S. M. Aston, Michael W. Coughlin, G. D. O'Dea, Bruno Giacomazzo, Giuseppe Intini, M. Drago, Guenakh Mitselmakher, B. A. Boom, A. M. Sergeev, T. Etzel, J.-G. Ducoin, M. Eisenmann, A. Dmitriev, S. Leavey, Hai-Ping Cheng, A. Iess, L. K. Nuttall, D. Wilken, S. Katsanevas, R. Goetz, C. Adams, R. M. Blair, D. Sigg, S. W. Ballmer, D. M. Shoemaker, Binlei Ding, V. Bossilkov, Lindsay DeMarchi, I. Khan, K. Siellez, D. Sentenac, R. Macas, G. Billingsley, S. Macfoy, Sergio Gaudio, D. B. Tanner, A. Trovato, Olivier Minazzoli, Magnus Manske, M. Razzano, C. C. Yancey, F. Vetrano, Zachariah B. Etienne, Jennifer Watchi, E. Maros, R. C. Walet, V. P. Mitrofanov, R. Colgan, C. S. Unnikrishnan, G. Moreno, V. Kondrashov, P. Leaci, S. Meshkov, Seog Oh, S. P. Stevenson, Achamveedu Gopakumar, R. Inta, C. J. Richardson, S. Klimenko, M. J. Yap, C. Palomba, W. G. Anderson, G. Cella, F.L. Linde, P. Booker, L. Milano, S. C. Tait, N. V. Krishnendu, A. Pasqualetti, W. Del Pozzo, W. M. Farr, A. C. Green, Fausto Acernese, M. Korobko, B. C. Pant, C. Messick, J. Derby, J. Healy, K. A. Thorne, A. Cumming, M. Denys, M. Tse, S. Ascenzi, S. E. Dwyer, R. M. Magee, David Keitel, V. Germain, S. J. Cooper, Giacomo Ciani, K. Rao, Yongjung Kim, Peter Weßels, I. A. Bilenko, L. Haegel, David J. Ottaway, B. P. Abbott, H. Vahlbruch, J. C. Mills, E. K. Gustafson, K. Riles, J. Y. Vinet, H. Middleton, S. Doravari, H. Heitmann, Piotr Jaranowski, M. S. Shahriar, P. Ruggi, M. Weinert, H. A. G. Gabbard, D. M. Macleod, Karan Jani, B. L. Swinkels, Arunava Mukherjee, S. Privitera, L. Glover, Imre Bartos, Isabel Cordero-Carrión, H. Qi, E. Genin, J. Zhang, F. Baldaccini, B. U. Gadre, A. Lartaux-Vollard, B. Irwin, R. Shink, L. Rei, Huang-Wei Pan, Gijs Nelemans, S. Vass, Kenneth A. Strain, Jimin George, R. Coyne, C. Gray, G. H. Ogin, T. J. Shaffer, M. Sieniawska, Fabrice Matichard, A. Paoli, K. A. Santiago, F. Fidecaro, G. M. Guidi, G. Cagnoli, Arnold Miller, H. N. Isa, Suvadeep Bose, V. Tiwari, V. Quetschke, Yann Bouffanais, Martin M. Fejer, L. F. Ortega, D. Lumaca, M. Pedraza, R. Bork, S. Ghonge, Y. Minenkov, P. Bacon, K. AultONeal, K. Chakravarti, E. D. Hall, L. Sammut, Lionel London, D. George, R. K. Lanza, Y. Boetzel, Alexander C. Jenkins, P. Dupej, Eric B. Flynn, Z. Márka, M. Mantovani, T. Prestegard, D. W. Yeeles, Xie Chen, A. Markowitz, Fabio Marchesoni, P. Hello, Samuel Deléglise, M. Merzougui, A. Fernandez-Galiana, S. M. Scott, M. Obergaulinger, Turlough P. Downes, F. Cavalier, A. Ain, R. J. Trudeau, K. Holt, Chunglee Kim, L. van der Schaaf, S. A. Pai, C. De Rossi, W. Parker, A. Gennai, Rahul Kumar, Harald P. Pfeiffer, Milan Gupta, G. Dálya, B. Gateley, G. Cho, J. C. Bayley, Aaron Buikema, V. Sandberg, E. J. King, M. J. Cowart, S. Koley, M. Boer, G. Mendell, S. J. Jadhav, B. Idzkowski, V. Loriette, V. Skliris, J. K. Blackburn, E. Chassande-Mottin, Shubhanshu Tiwari, G. Koekoek, L. Trozzo, C. Pankow, P. M. Meyers, Koh Ueno, Christian Pedersen, Albert Lazzarini, Kyungmin Kim, N. Koper, H. Wittel, M. Deenadayalan, B. O'Reilly, A. W. Jones, Sheila Rowan, S. G. Schwalbe, D. Pascucci, R. De Pietri, S. Mitra, T. Sadecki, W. Ren, Rocco Romano, John D. Scott, J. Z. Wang, S. Grunewald, R. Prasanna, R. Cotesta, R. G. Ormiston, S. Kaufer, Rainer Weiss, David E. McClelland, Paul J. Groot, M. Zevin, R. A. Mercer, S. Ossokine, Jinsook Kim, Rebecca Fisher, J. Li, A. M. Holgado, H. Fair, Samaya Nissanke, X. Liu, M. A. Bizouard, K. Bossie, John Veitch, J. Lehmann, Al Imran Malik, K. G. Arun, J. D. Tasson, C. K. Cheong, J. R. Gair, M. Fitz-Axen, B. K. Berger, S. D'Antonio, N. Arnaud, K. E. Ramirez, W. Z. Korth, Daniel E. Holz, F. Di Renzo, Torrey Cullen, B. J. J. Slagmolen, Archana Pai, F. Paoletti, Vijay Varma, M. MacInnis, Marco Romanelli, M. Fyffe, F. Cipriano, David Blair, C. Fee, Gabriela Gonzalez, F. Aubin, G. Stratta, Jesper Munch, K. R. Corley, A. Mullavey, T. J. N. Nelson, J. Birch, S. Bae, P. Rapagnani, F. J. Raab, D. Tuyenbayev, B. Patricelli, D. S. Wu, Margaret Millhouse, S. Barnum, D. Buskulic, S. G. Gaonkar, E. Coccia, M. E. Zucker, C. Graef, B. A. Weaver, Xiaohui Fan, J. G. Rollins, Richard O'Shaughnessy, B. Barr, M. De Laurentis, D. Ugolini, P. Clearwater, G. Valdes, David Jones, M. R. Ganija, L.-W. Wei, Haixing Miao, G. Bogaert, R. Taylor, P. Popolizio, Koji Arai, Ryan Lynch, A. D. Viets, D. Meacher, E. J. Fauchon-Jones, E. J. Sanchez, S. Ponrathnam, G. A. Prodi, K. L. Dooley, Fangchen Feng, Lisa Barsotti, Kris Ryan, E. A. Quintero, Marco Cavaglia, J.J. Bero, Leo Tsukada, David H. Shoemaker, M. Lormand, D. J. Stops, S. Karki, Anirban Dasgupta, E. Z. Hamilton, R. J. G. Jonker, J. S. H. Lee, T. Dal Canton, J. Warner, R. Passaquieti, D. Verkindt, Mairi Sakellariadou, G. Pillant, S. H. R. Yuen, Keith Rose, K. S. Karvinen, F. Martelli, C. Rajan, Pablo Cerdá-Durán, Peter R. Saulson, V. Sequino, Tenglin Li, R. DeSalvo, D. Estevez, B. Pang, Paul T. Baker, O. V. Palashov, Sean T. McWilliams, D. Rosińska, J. C. Barayoga, V. Fafone, R. Tso, Jonathan Richardson, F. Piergiovanni, Chang-Hwan Lee, N. Sanchis-Gual, N. Radulescu, L. Mereni, Terry G. McRae, S. Mastrogiovanni, Richard J. Abbott, L. G. Prokhorov, Patrick M. Koch, S. Antier, S. Banagiri, A. Grant, D. Chatterjee, T. L. Lam, A. Pele, A. Chiummo, Nergis Mavalvala, Alessandro Longo, Richard J. Oram, M. Davier, Jerome Degallaix, François Bondu, F. Badaracco, Sebastian Khan, B. C. Barish, Hartmut Grote, R. J. E. Smith, John A. Clark, Ben Farr, Christophe Collette, Ho-Gyu Lee, G. Losurdo, Luca Gammaitoni, R. Metzdorff, C. J. Perez, B. D. O'Brien, M. K. M. Bader, O. Chaibi, Devon S. Johnson, C. Bradaschia, P. Oppermann, Neil J. Cornish, S. Frasca, M. Di Giovanni, Ik Siong Heng, Kai Staats, F-L. Lin, L. Conti, M. Chaturvedi, S. Márka, Stephen Fairhurst, Carl Blair, Peter Aufmuth, T. Di Girolamo, V. Mangano, A. L. Miller, S. Ghosh, László Á. Gergely, A. Macquet, P. Astone, B. Lantz, Daichi Tsuna, K. Mogushi, P. J. King, J. T. Whelan, S. G. Crowder, J. Feicht, Joey Shapiro Key, J. R. Sanders, António Alves da Silva, Q. Chu, S. V. Angelova, L. Magaña Zertuche, Lili Yang, Laura Cadonati, D. A. Steer, M. Branchesi, Zefeng Zhou, D. Y. T. Pong, L. Kleybolte, E. Massera, F. Wellmann, Edward Seidel, O. E. S. Sauter, J. Woehler, S. Chung, K. S. Phukon, A. Avila-Alvarez, Chad Hanna, A. Bramley, C. Kimball, J. Oberling, M. Pirello, K. Gill, Walter Winkler, A. S. Markosyan, Harald Lück, J. Bidler, M. Cho, G. Gaur, S. C. McGuire, J. F. Read, F. Nocera, C. Zhao, Alicia M. Sintes, S. Di Pace, K. Haris, T. Zhang, N. Demos, Thibaut Jacqmin, T. Regimbau, I. Maksimovic, G. Hemming, S. M. Koehlenbeck, M. Saleem, M. Oliver, Douglas Davis, Geraint Pratten, E. Goetz, Tarun Souradeep, Andrea Taracchini, D. Bersanetti, G. Ashton, S. Penn, J. V. van Heijningen, Yu Wang, F. Thies, G. L. Mansell, V. Dattilo, Edwin J. Son, Eric Thrane, Stefan Hild, Y. Ma, A. Brillet, C. Michel, M. Vardaro, Sarah Caudill, T. D. Knowles, F. Robinet, V. B. Adya, J. K. Wofford, F. Cleva, M. P. Ross, T. B. Edo, M. Pichot, Maximiliano Isi, E. M. Gretarsson, Ying Guo, D. Beniwal, Peter Fritschel, Wenxiao Wang, M. Masso-Reid, S. Kwang, L. E. Sanchez, Enrico Calloni, G. Traylor, Thomas Corbitt, L. Salconi, C. A. Costa, Zhihui Du, Laboratoire des matériaux avancés (LMA), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, Laboratoire de l'Accélérateur Linéaire (LAL), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), AstroParticule et Cosmologie (APC (UMR_7164)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), (Astro)-Particles Physics, Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)

Subjects
Physics, [PHYS]Physics [physics], 010504 meteorology & atmospheric sciences, Gravitational wave, Astronomy, Astronomy and Astrophysics, 01 natural sciences, LIGO, Supernova, Fomalhaut, Space and Planetary Science, 0103 physical sciences, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

Equation (5) of the published article?(Abbott et al. 2019) is in error; it should read (Formula Presented) The upper limits on ò presented in the published article are unaffected by this error.

Published
2021

31. Compressing the cosmological information in one-dimensional correlations of the Lyman-$\alpha$ forest

Author

Christian Pedersen, Andreu Font-Ribera, and Nickolay Y. Gnedin

Subjects
Cosmology and Nongalactic Astrophysics (astro-ph.CO), Space and Planetary Science, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

Observations of the Lyman-$\alpha$ (Ly$\alpha$) forest from spectroscopic surveys such as BOSS/eBOSS, or the ongoing DESI, offer a unique window to study the growth of structure on megaparsec scales. Interpretation of these measurements is a complicated task, requiring hydrodynamical simulations to model and marginalise over the thermal and ionisation state of the intergalactic medium. This complexity has limited the use of Ly$\alpha$ clustering measurements in joint cosmological analyses. In this work we show that the cosmological information content of the 1D power spectrum ($P_\mathrm{1D}$) of the Ly$\alpha$ forest can be compressed into a simple two-parameter likelihood without any significant loss of constraining power. We simulate $P_\mathrm{1D}$ measurements from DESI using hydrodynamical simulations and show that the compressed likelihood is model independent and lossless, recovering unbiased results even in the presence of massive neutrinos or running of the primordial power spectrum., Comment: Published in ApJ. 17 pages, 7 figures

Published
2022

32. Characterization of the acidity and basicity of green solvents by NMR techniques

Author

Yan Qiao, Hui Chang, Kemeng Shi, Jing Shi, Christian Pedersen, and Yingxiong Wang

Subjects
chemistry.chemical_classification, chemistry.chemical_compound, Base (chemistry), chemistry, Inorganic chemistry, Ionic liquid, Molecule, Molten salt, Hydrate, pH meter, Pyrrole, Eutectic system
Abstract

The acidity and basicity of the solvents can influence the reaction outcome notably, and hence the precise measurement of pH is important for reaction. However, not all the pH values of organic solvents can be determined with a classic pH meter straightly. In this research, the acidity and basicity of environmentally friendly green solvents, such as ZnCl2 molten salt hydrate, ionic liquids (ILs) and deep eutectic solvents (DESs), were characterized by 31P and 1H NMR spectroscopy using trimethylphosphine oxide (TMPO) and pyrrole as probe molecules at 298 K. For the ZnCl2 molten salt hydrate, the acidic strength of the ZnCl2 molten salt hydrate increased with the concentration of ZnCl2. By using the 1H-pyrrole NMR approach, it was found that the base strength of amino acid-based ILs follows the order: [Ch][Lys] > [Ch][His].

Published
2021

33. Mechanical coupling of supracellular stress amplification and tissue fluidization during exit from quiescence

Author

Emma Lång, Christian Pedersen, Anna Lång, Pernille Blicher, Arne Klungland, Andreas Carlson, and Stig Ove Bøe

Subjects
Keratinocytes, Multidisciplinary, Cell Cycle, Homeostasis, Humans, Cell Division, Cell Proliferation
Abstract

Cellular quiescence is a state of reversible cell cycle arrest that is associated with tissue dormancy. Timely regulated entry into and exit from quiescence is important for processes such as tissue homeostasis, tissue repair, stem cell maintenance, developmental processes, and immunity. However, little is known about processes that control the mechanical adaption to cell behavior changes during the transition from quiescence to proliferation. Here, we show that quiescent human keratinocyte monolayers sustain an actinomyosin-based system that facilitates global cell sheet displacements upon serum-stimulated exit from quiescence. Mechanistically, exposure of quiescent cells to serum-borne mitogens leads to rapid amplification of preexisting contractile sites, leading to a burst in monolayer tension that subsequently drives large-scale displacements of otherwise motility-restricted monolayers. The stress level after quiescence exit correlates with the level of quiescence depth at the time of activation, and a critical stress magnitude must be reached to overcome the cell sheet displacement barrier. The study shows that static quiescent cell monolayers are mechanically poised for motility, and it identifies global stress amplification as a mechanism for overcoming motility restrictions in confined confluent cell monolayers.

Published
2022

34. Ternary deep eutectic solvents catalyzed d-glucosamine self-condensation to deoxyfructosazine: NMR study

Author

Xianglin Hou, Christian Pedersen, Jiaojiao Zhang, Zhenzhou Zhang, Yingxiong Wang, Pengfei Liu, and Rui Liu

Subjects
Hydrogen bonding, TJ807-830, 02 engineering and technology, Reaction intermediate, 010402 general chemistry, 01 natural sciences, Renewable energy sources, Catalysis, chemistry.chemical_compound, QH540-549.5, Ecology, biology, Ternary deep eutectic solvents, Renewable Energy, Sustainability and the Environment, Hydrogen bond, Active site, Self-condensation, 021001 nanoscience & nanotechnology, NMR, 0104 chemical sciences, chemistry, Yield (chemistry), D-glucosamine, biology.protein, Proton NMR, Physical chemistry, 0210 nano-technology, Deoxyfructosazine, Choline chloride
Abstract

Ternary deep eutectic solvents (TDESs) comprising choline chloride (ChCl), glycerol and l -arginine were synthesized as catalysts and solvents for the conversion of d -glucosamine (GlcNH2) into deoxyfructosazine (DOF). The interactions between these three components in the prepared TDESs were studied by 1H-, 35Cl-NMR spectra and 1H diffusion-ordered spectroscopy (DOSY) measurements. The chemical shift changes of active hydrogen in the 1H-NMR spectra of TDES system and widening of signals in the 35Cl-NMR spectra confirmed the hydrogen bonding interaction between the components, which was further supported by the decrease of diffusion coefficients (D) of the TDES components according to 1H DOSY measurements. The influences of reaction temperature and l -arginine content in the TDESs on the yield of DOF were also studied. The experimental results have shown that when the molar ratio of ChCl, glycerol, and l -arginine was 1:2:0.1, DOF was the major product with a yield of 22.6% at 90 °C for 120 min. The chemical shift titration indicated that the carboxyl group of l -arginine in the TDES is the catalytical active site, so the mechanism of the catalytic reaction between GlcNH2 and the TDES was proposed. Moreover, a reaction intermediate, dihydrofructosazine, was identified in the self-condensation reaction of GlcNH2 by an in situ 1H NMR technique.

Published
2021

35. Comparison of hearing aid fitting effectiveness with audiograms from either user-operated or traditional audiometry in a clinical setting: a study protocol for a blinded non-inferiority randomised controlled trial

Author

Carl Christian Pedersen, Ellen Raben Pedersen, Søren Laugesen, Raul Sanchez-Lopez, Jacob Nielsen, Chris Bang Sørensen, Christos Sidiras, René Gyldenlund Pedersen, and Jesper Hvass Schmidt

Subjects
General Medicine
Abstract

IntroductionThere is a worldwide need to enhance the capacity of audiometry testing. The objective of this study is to compare the User-operated Audiometry (UAud) system with traditional audiometry in a clinical setting, by investigating if hearing aid effectiveness based on UAud is non-inferior to hearing aid effectiveness based on traditional audiometry, and whether thresholds obtained with the user-operated version of the Audible Contrast Threshold (ACT) test correlates to traditional measures of speech intelligibility.Methods and analysisThe design will be a blinded non-inferiority randomised controlled trial. 250 adults referred for hearing aid treatment will be enrolled in the study. Study participants will be tested using both traditional audiometry as well as the UAud system and they will answer the questionnaire Speech, Spatial and Qualities of Hearing Scale (SSQ12) at baseline. Participants will be randomly divided to receive hearing aids fitted based on either UAud or traditional audiometry. Three months after participants have started using their hearing aids, they will undergo a hearing in noise test with hearing aids to measure their speech-in-noise performance and answer the following questionnaires: SSQ12, the Abbreviated Profile of Hearing Aid Benefit and the International Outcome Inventory for Hearing Aids. The primary outcome is a comparison of the change in SSQ12 scores from baseline to follow-up between the two groups. Participants will undergo the user-operated ACT test of spectro-temporal modulation sensitivity as part of the UAud system. The ACT results will be compared with measures of speech intelligibility from the traditional audiometry session and follow-up measurements.Ethics and disseminationThe project was evaluated by the Research Ethics Committee of Southern Denmark and judged not to need approval. The findings will be submitted to an international peer-reviewed journal and presented at national and international conferences.Trial registration numberNCT05043207.

Published
2023

36. Non-linearities in the Lyman-$\alpha$ forest and in its cross-correlation with dark matter halos

Author

Jahmour J. Givans, Andreu Font-Ribera, Anže Slosar, Louise Seeyave, Christian Pedersen, Keir K. Rogers, Mathias Garny, Diego Blas, and Vid Iršič

Subjects
Cosmology and Nongalactic Astrophysics (astro-ph.CO), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

Three-dimensional correlations of the Lyman-$\alpha$ (Ly$\alpha$) forest and cross correlations between the Ly$\alpha$ forest and quasars have been measured on large scales, allowing a precise measurement of the baryon acoustic oscillation (BAO) feature at redshifts $z>2$. These 3D correlations are often modelled using linear perturbation theory, but full-shape analyses to extract cosmological information beyond BAO will require more realistic models capable of describing non-linearities present at smaller scales. We present a measurement of the Ly$\alpha$ forest flux power spectrum from large hydrodynamic simulations -- the Sherwood simulations -- and compare it to different models describing the small-scale deviations from linear theory. We confirm that the model presented in Arinyo-i-Prats et al. (2015) fits the measured 3D power up to $k=10\, h\rm{Mpc^{-1}}$ with an accuracy better than 5%, and show that the same model can also describe the 1D correlations with similar precision. We also present, for the first time, an equivalent study for the cross-power spectrum of halos with the Ly$\alpha$ forest, and we discuss different challenges we face when modelling the cross-power spectrum beyond linear scales. We make all our measured power spectra public in \url{https://github.com/andreufont/sherwood_p3d}. This study is a step towards joint analyses of 1D and 3D flux correlations, and towards using the quasar-Ly$\alpha$ cross-correlation beyond BAO analyses., Comment: 31 pages, 19 figures

Published
2022

37. Reactivity, Selectivity, and Synthesis of 4‐ C ‐Silylated Glycosyl Donors and 4‐Deoxy Analogues

Author

Martin Jaeger Pedersen and Christian Pedersen

Subjects
Glycosylation, Anomer, Silylation, 010405 organic chemistry, Stereochemistry, General Chemistry, 010402 general chemistry, 01 natural sciences, Catalysis, 0104 chemical sciences, chemistry.chemical_compound, Glucoside, chemistry, Reactivity (chemistry), Glycosyl, Cellulose, Selectivity
Abstract

A method for introducing dimethylphenylsilyl at the 4-position in carbohydrates has been developed. Two C-silylated glycosyl donors were prepared via levoglucosenone, starting from cellulose. The glycosylation properties were studied using three glucoside acceptors, a 3-OH, 4-OH, and 6-OH. Compared with the 4-deoxy variant, it was found that the anomeric selectivity was influenced more by the C-2 substituents orientation than the silyl in the 4-position. In general, the reactivity of these donors was higher than the corresponding 4-deoxy-analogue, albeit a competition experiment showed that the introduction of a C-Si increases the relative reactivity by a modest factor of around two.

Published
2020

38. Easy access to a carbohydrate-based template for stimuli-responsive surfactants

Author

Daniel Raydan, Thomas Holmstrøm, and Christian Pedersen

Subjects
chemistry.chemical_classification, Anomer, Stimuli responsive, synthesis, Chemistry, Carboxylic acid, Levoglucosan, Organic Chemistry, emulsifiers, carbohydrates, Carbohydrate, Combinatorial chemistry, Full Research Paper, stimuli-responsive, surfactants, lcsh:QD241-441, chemistry.chemical_compound, lcsh:Organic chemistry, Block (telecommunications), Molecule, lcsh:Q, lcsh:Science
Abstract

In this paper we describe the synthesis of a new carbohydrate-based building block functionalized with azido or amino groups on the 2 and 4 positions. The building block can be synthesized in anomerically pure form in only five scalable steps starting from commercially available levoglucosan. It was shown that the building block could undergo alkylations under strongly basic conditions. The building block with azido groups could furthermore take part in CuAAC reactions, generating derivatives with ester or carboxylic acid functionalities. In addition, the anomeric mixture of the building block was used for the synthesis of a molecule that could act as an emulsifier only in the presence of Zn2+ ions.

Published
2020

41. Enzyme-Catalyzed Regioselective Acetylation of Functionalized Glycosides

Author

Thomas Holmstrøm and Christian Pedersen

Subjects
chemistry.chemical_classification, Enzyme, chemistry, Enzyme catalyzed, Acetylation, Site selectivity, Organic Chemistry, Site selective, Glycoside, Regioselectivity, Physical and Theoretical Chemistry, Combinatorial chemistry, Enzyme catalysis
Published
2020

43. Catalytic and Atom‐Economic Glycosylation using Glycosyl Formates and Cheap Metal Salts

Author

Christian Herrstedt Hammelev, Liang Yang, and Christian Pedersen

Subjects
animal structures, Glycosylation, Chemistry, Formic acid, General Chemical Engineering, Side reaction, macromolecular substances, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Combinatorial chemistry, 0104 chemical sciences, Catalysis, carbohydrates (lipids), chemistry.chemical_compound, General Energy, Atom economy, Environmental Chemistry, lipids (amino acids, peptides, and proteins), General Materials Science, Glycosyl, Dehydrogenation, Orthoester, 0210 nano-technology
Abstract

Benzylated glycosyl formates have been synthesized in one step from the corresponding hemiacetal or orthoester with formic acid as the sole reagent. The glycosyl formates are used as glycosyl donors under catalytic conditions with cheap metal catalysts based on iron or bismuth. A 13 C NMR spectroscopic method is developed and evaluated for screening reactions conditions, giving precise information on the selectivity, yield, and byproducts formed. The major side reaction is transesterification, which gives the formylated acceptor and regenerates the hemiacetal. By using this approach, catalyst loadings and solvents are optimized and the scope of the glycosylation is evaluated for a variety of glycosyl donors and acceptors. A proof of concept for a traceless glycosylation, utilizing a dual-purpose iron catalyst that catalyzes both glycosylation and dehydrogenation of formic acid, is also provided.

Published
2020

44. Development and Characterization of Mouse Monoclonal Antibodies Specific for Clostridiodes (Clostridium) difficile Lipoteichoic Acid

Author

Nicolas Gisch, Martin A Rossotti, Wouter F. J. Hogendorf, Susan M. Logan, Henk van Faassen, Chantelle M. Cairns, Kevin A. Henry, Annie Aubry, Greg Hussack, Andrew D. Cox, Frank St. Michael, and Christian Pedersen

Subjects
0301 basic medicine, biology, 010405 organic chemistry, Chemistry, medicine.drug_class, General Medicine, Pseudomembranous colitis, Clostridium difficile, Monoclonal antibody, 01 natural sciences, Biochemistry, Epitope, 0104 chemical sciences, Microbiology, 03 medical and health sciences, 030104 developmental biology, Antigen, biology.protein, medicine, Molecular Medicine, Lipoteichoic acid, Antibody, Antitoxin
Abstract

Clostridiodes (Clostridium) difficile is an anaerobic Gram-positive, spore-forming nosocomial, gastrointestinal pathogen causing C. difficile-associated disease with symptoms ranging from mild cases of antibiotic-associated diarrhea to fatal pseudomembranous colitis. We developed murine monoclonal antibodies (mAbs) specific for a conserved cell surface antigen, lipoteichoic acid (LTA)of C. difficile. The mAbs were characterized in terms of their thermal stability, solubility, and their binding to LTA by surface plasmon resonance and competitive ELISA. Synthetic LTA molecules were prepared in order to better define the minimum epitope required to mimic the natural antigen, and three repeat units of the polymer were required for optimal recognition. One of the murine mAbs was chimerized with human constant region domains and was found to recognize the target antigen identically to the mouse version. These mAbs may be useful as therapeutics (standalone, in conjunction with known antitoxin approaches, or as delivery vehicles for antibody drug conjugates targeting the bacterium), as diagnostic agents, and in infection control applications.

Published
2020

45. Palladium(0)‐Catalyzed Rearrangement of Allylic Esters

Author

Bo Michael Jessen, Amanda Birgitte Sølvhøj, Jun Miyatake Ondozabal, Christian Pedersen, Esben Taarning, and Robert Madsen

Subjects
Allylic rearrangement, Reaction mechanism, Chemistry, Polymer chemistry, chemistry.chemical_element, Homogeneous catalysis, General Chemistry, Catalysis, Palladium
Published
2020

46. Scalable synthesis of hydroxymethyl alkylfuranoates as stable 2,5-furandicarboxylic acid precursors

Author

Arminas Jurys, Martin Jaeger Pedersen, and Christian Pedersen

Subjects
Precipitation (chemistry), fungi, food and beverages, Pollution, law.invention, Gluconolactone, chemistry.chemical_compound, chemistry, law, Reagent, Yield (chemistry), Environmental Chemistry, Organic chemistry, Hydroxymethyl, 2,5-Furandicarboxylic acid, Distillation, Gram
Abstract

Hydroxymethyl furanoic acid and its derivatives have been synthesized in high yields and purity from gluconolactone. The reaction sequence allows the recovery of reagents and the use of bio-friendly chemicals and solvents, and can easily be scaled up. The reaction product on a >100 gram scale can be purified by a single purification method, such as distillation or precipitation. The overall yield is above 50%.

Published
2020

48. Comparison of AgGaS2 and AgGaSe2 for Long Wavelength Upconversion

Author

Christian Pedersen, Peter Tidemand-Lichtenberg, and Rasmus Lyngbye Pedersen

Abstract

AgGaS2 and AgGaSe2 are tested side by side for infrared upconversion detection in the 5-20 µm range, under similar experimental conditions. We discuss the two crystals with regard to upconversion efficiency, sensitivity and spectral range.

Published
2022

49. Diversity patterns in high‐latitude grasslands

Author

Jutta Kapfer, Wenche Dramstad, Christian Pedersen, Hanne Sickel, and Einar Heegaard

Subjects
Ecology, Management, Monitoring, Policy and Law, Nature and Landscape Conservation
Published
2022

50. Stereoselective O ‐Glycosylations by Pyrylium Salt Organocatalysis**

Author

Michael Martin Nielsen, Thomas Holmstrøm, and Christian Pedersen

Subjects
chemistry.chemical_classification, Pyrylium salt, Glycosylation, Carbohydrate chemistry, Chemistry, General Chemistry, General Medicine, Combinatorial chemistry, Catalysis, chemistry.chemical_compound, Stereospecificity, Organocatalysis, Electrophile, Alkyl
Abstract

Despite many years of invention, the field of carbohydrate chemistry remains rather inaccessible to non-specialists, which limits the scientific impact and reach of the discoveries made in the field. Aiming to increase the availability of stereoselective glycosylation chemistry for non-specialists, we have discovered that several commercially available pyrylium salts catalyze stereoselective O-glycosylations of a wide range of phenols and alkyl alcohols. This catalytic reaction utilizes trichloroacetimidates, an easily accessible and synthetically proven electrophile, takes place under air and only initiates when all three reagents are mixed, which should provide better reproducibility by non-specialists. The reaction exhibits varying degrees of stereospecificity, resulting in β-selective glycosylations from α-trichloroacetimidates, whilst an α-selective glycosylation proceeds from β-trichloroacetimidates. A mechanistic study revealed that the reaction likely proceeds via an SN2-like substitution on the protonated electrophile.

Published
2021

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