| 1. |
- Kanai, M, et al.
(författare)
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- 2023
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swepub:Mat__t
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| 2. |
- Bralower, T, et al.
(författare)
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The Habitat of the Nascent Chicxulub Crater
- 2020
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Ingår i: AGU Advances. - : American Geophysical Union (AGU). ; 1
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Tidskriftsartikel (refereegranskat)abstract
- An expanded sedimentary section provides an opportunity to elucidate conditions in the nascent Chicxulub crater during the hours to millennia after the Cretaceous‐Paleogene (K‐Pg) boundary impact. The sediments were deposited by tsunami followed by seiche waves as energy in the crater declined, culminating in a thin hemipelagic marlstone unit that contains atmospheric fallout. Seiche deposits are predominantly composed of calcite formed by decarbonation of the target limestone during impact followed by carbonation in the water column. Temperatures recorded by clumped isotopes of these carbonates are in excess of 70°C, with heat likely derived from the central impact melt pool. Yet, despite the turbidity and heat, waters within the nascent crater basin soon became a viable habitat for a remarkably diverse cross section of the food chain. The earliest seiche layers deposited with days or weeks of the impact contain earliest Danian nannoplankton and dinocyst survivors. The hemipelagic marlstone representing the subsequent years to a few millennia contains a nearly monogeneric calcareous dinoflagellate resting cyst assemblage suggesting deteriorating environmental conditions, with one interpretation involving low light levels in the impact aftermath. At the same horizon, microbial fossils indicate a thriving bacterial community and unique phosphatic fossils including appendages of pelagic crustaceans, coprolites andbacteria‐tunneled fish bone, suggesting that this rapid recovery of the base of the food chain may have supported the survival of larger, higher trophic‐level organisms. The extraordinarily diverse fossil assemblage indicates that the crater was a unique habitat in the immediate impact aftermath, possibly as aresult of heat and nutrients supplied by hydrothermal activity.
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| 3. |
- Mangold, N., et al.
(författare)
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Perseverance rover reveals an ancient delta-lake system and flood deposits at Jezero crater, Mars
- 2021
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 374:6568
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Tidskriftsartikel (refereegranskat)abstract
- Observations from orbital spacecraft have shown that Jezero crater on Mars contains a prominent fan-shaped body of sedimentary rock deposited at its western margin. The Perseverance rover landed in Jezero crater in February 2021. We analyze images taken by the rover in the 3 months after landing. The fan has outcrop faces, which were invisible from orbit, that record the hydrological evolution of Jezero crater. We interpret the presence of inclined strata in these outcrops as evidence of deltas that advanced into a lake. In contrast, the uppermost fan strata are composed of boulder conglomerates, which imply deposition by episodic high-energy floods. This sedimentary succession indicates a transition from sustained hydrologic activity in a persistent lake environment to highly energetic short-duration fluvial flows.
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| 4. |
- Brem, Jürgen, et al.
(författare)
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Imitation of β-lactam binding enables broad-spectrum metallo-β-lactamase inhibitors
- 2022
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Ingår i: Nature Chemistry. - : Springer Nature. - 1755-4330 .- 1755-4349. ; 14:1, s. 15-24
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Tidskriftsartikel (refereegranskat)abstract
- Carbapenems are vital antibiotics, but their efficacy is increasingly compromised by metallo-β-lactamases (MBLs). Here we report the discovery and optimization of potent broad-spectrum MBL inhibitors. A high-throughput screen for NDM-1 inhibitors identified indole-2-carboxylates (InCs) as potential β-lactamase stable β-lactam mimics. Subsequent structure-activity relationship studies revealed InCs as a new class of potent MBL inhibitor, active against all MBL classes of major clinical relevance. Crystallographic studies revealed a binding mode of the InCs to MBLs that, in some regards, mimics that predicted for intact carbapenems, including with respect to maintenance of the Zn(II)-bound hydroxyl, and in other regards mimics binding observed in MBL-carbapenem product complexes. InCs restore carbapenem activity against multiple drug-resistant Gram-negative bacteria and have a low frequency of resistance. InCs also have a good in vivo safety profile, and when combined with meropenem show a strong in vivo efficacy in peritonitis and thigh mouse infection models.
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| 5. |
- Hoencamp, Claire, et al.
(författare)
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3D genomics across the tree of life reveals condensin II as a determinant of architecture type
- 2021
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 372:6545, s. 984-989
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Tidskriftsartikel (refereegranskat)abstract
- We investigated genome folding across the eukaryotic tree of life. We find two types of three-dimensional (3D) genome architectures at the chromosome scale. Each type appears and disappears repeatedly during eukaryotic evolution. The type of genome architecture that an organism exhibits correlates with the absence of condensin II subunits. Moreover, condensin II depletion converts the architecture of the human genome to a state resembling that seen in organisms such as fungi or mosquitoes. In this state, centromeres cluster together at nucleoli, and heterochromatin domains merge. We propose a physical model in which lengthwise compaction of chromosomes by condensin II during mitosis determines chromosome-scale genome architecture, with effects that are retained during the subsequent interphase. This mechanism likely has been conserved since the last common ancestor of all eukaryotes.
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| 6. |
- Diwekar, U., et al.
(författare)
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A perspective on the role of uncertainty in sustainability science and engineering
- 2021
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Ingår i: Resources, Conservation and Recycling. - : Elsevier BV. - 0921-3449 .- 1879-0658. ; 164
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The Trans-Atlantic Research and Development Interchange on Sustainability Workshop (TARDIS) is a meeting on scientific topics related to sustainability. The 2019 workshop theme was "On the Role of Uncertainty in Managing the Earth for Global Sustainability." This paper presents the perspectives on this topic derived from talks and discussions at the 2019 TARDIS workshop. There are four kinds of uncertainties encountered in sustainability ranging from clear enough futures to true surprises. The current state-of-the-art in assessing and mitigating these uncertainties is discussed.
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| 7. |
- Sun, Vivian Z., et al.
(författare)
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Overview and Results From the Mars 2020 Perseverance Rover's First Science Campaign on the Jezero Crater Floor
- 2023
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Ingår i: Journal of Geophysical Research: Planets. - : John Wiley and Sons Inc. - 2169-9097 .- 2169-9100. ; 128:6
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Tidskriftsartikel (refereegranskat)abstract
- The Mars 2020 Perseverance rover landed in Jezero crater on 18 February 2021. After a 100-sol period of commissioning and the Ingenuity Helicopter technology demonstration, Perseverance began its first science campaign to explore the enigmatic Jezero crater floor, whose igneous or sedimentary origins have been much debated in the scientific community. This paper describes the campaign plan developed to explore the crater floor's Máaz and Séítah formations and summarizes the results of the campaign between sols 100–379. By the end of the campaign, Perseverance had traversed more than 5 km, created seven abrasion patches, and sealed nine samples and a witness tube. Analysis of remote and proximity science observations show that the Máaz and Séítah formations are igneous in origin and composed of five and two geologic members, respectively. The Séítah formation represents the olivine-rich cumulate formed from differentiation of a slowly cooling melt or magma body, and the Máaz formation likely represents a separate series of lava flows emplaced after Séítah. The Máaz and Séítah rocks also preserve evidence of multiple episodes of aqueous alteration in secondary minerals like carbonate, Fe/Mg phyllosilicates, sulfates, and perchlorate, and surficial coatings. Post-emplacement processes tilted the rocks near the Máaz-Séítah contact and substantial erosion modified the crater floor rocks to their present-day expressions. Results from this crater floor campaign, including those obtained upon return of the collected samples, will help to build the geologic history of events that occurred in Jezero crater and provide time constraints on the formation of the Jezero delta.
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