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Recent research suggests that major meteorite impact events into a Late Hesperian/Early Amazonian ocean likely produced a mega‐tsunami that would have resurfaced coastal areas in northwestern Arabia Terra. The orientations of the associated lobate deposits, a conspicuous type of landforms called Thumbprint Terrain, suggests that if an impact event triggered the mega‐tsunami, the most likely location of the source crater is within the northern plains regions situated north of Arabia Terra. This study focuses on the identification of impact craters that impacted into the ocean and are likely to have produced the tsunami. We selected 10 complex impact craters, based on their diameters, location, and geomorphic characteristics. Of those, the Late Hesperian ~120‐km‐diameter Lomonosov crater exhibits a unique topographic plan view asymmetry (compared to other similar‐sized and similar‐aged craters in the northern plains such as Micoud, Korolev, and Milankovic). We attribute its broad and shallow rim, in part, to an impact into a shallow ocean as well as its subsequent erosion from the collapsing transient water cavity. The likely marine formation of the Lomonosov crater, and the apparent agreement in its age with that of the Thumbprint Terrain unit (~3 Ga), strongly suggests that it was the source crater of the tsunami. These results have implications for the stability of a late northern ocean on Mars. Unusual morphometric characteristics of Lomonosov crater in comparison to the other northern complex cratersLomonosov crater was probably due to the presence of a shallow ocean of liquid water at the time of the impactAgreement of the Lomonosov age with that of the Thumbprint Terrain unit (~3 Ga) suggests that it was the source crater of the tsunami

Seismic activity generated by impacts depends on impact conditions and properties of the impact site. Here, we combined mapping of the regolith thickness with numerical impact simulations to better estimate the seismic efficiency and seismic moment generated in small impact events in the uppermost crust on Mars. We used mapping of crater morphology to determine the regolith thickness that craters formed in. We found that local regolith thickness in the late Amazonian units is between 4 and 9 m. Combined with previous estimates for the NASA InSight landing site, we composed a more realistic uppermost crust analog and implemented it in numerical impact simulations. We estimated the seismic efficiency and seismic moment for small craters on Mars impacting a non‐porous or fractured bedrock overlaid by 5, 10, or 15 m thick regolith. Seismic energy showed more dependence on target properties. Three orders of magnitude more energy were produced in stronger targets. The seismic moment does not depend on target properties, and we confirm that seismic moment is almost proportional to impact momentum. The resulting seismic moment is in agreement up to a factor of 4 between different target types. We improved the scaling relationships developed from numerical simulations used in seismic moment approximations by constraining its dependence on more realistic target properties. Small impacts form in the top few meters of the crust of Mars. From the NASA InSight mission data, we learned that the uppermost crust of Mars is layered. Here, we mapped and used rocky ejecta craters as a proxy to estimate the thickness of this top layer. We demonstrated that a younger, late Amazonian geological unit, has a thinner top regolith layer (4–9 m) compared to an older, Hesperian unit (3–17 m). We modeled several target scenarios, constrained by mapping results, and performed a suite of numerical simulations of small impacts. From these simulations, we determined a relationship between impact‐generated seismic energy and the seismic moment for different types of Martian upper‐crust analogs. Our models show that impact‐generated seismic energy strongly depends on target properties (three orders of difference among different analogs investigated here). On the contrary, seismic moment shows agreement up to a factor of 4 in different targets. We discussed our modeling results to the newly detected impacts on Mars, and confirmed that our models are reliable for predicting seismic moments of small impacts. Our results contribute to the understanding of the size and energy of impact‐generated seismic sources in different target analogs. Using rocky ejecta craters, we mapped regolith thickness on Mars and found that in the late Amazonian volcanic unit, it is 4–9 mSeismic efficiency shows larger sensitivity on target properties (up to three orders of magnitude) than the seismic moment (factor of four)A comparison of numerical simulations with the new seismic detections of craters on Mars showed agreement with our models Using rocky ejecta craters, we mapped regolith thickness on Mars and found that in the late Amazonian volcanic unit, it is 4–9 m Seismic efficiency shows larger sensitivity on target properties (up to three orders of magnitude) than the seismic moment (factor of four) A comparison of numerical simulations with the new seismic detections of craters on Mars showed agreement with our models

1H-Imidazo-[4,5-c]quinolines were prepared while investigating novel nucleoside analogues as potential antiviral agents. While these compounds showed no direct antiviral activity when tested in a number of cell culture systems, some demonstrated potent inhibition of virus lesion development in an intravaginal guinea pig herpes simplex virus-2 assay. We have determined that the in vivo antiviral activity can be attributed to the ability of these molecules to induce the production of cytokines, especially interferon (IFN), in this model. Subsequently, we found that the compounds also induce in vitro production of IFN in human peripheral blood mononuclear cells (hPBMCs). The in vitro results reported herein and the in vivo results reported previously led to the discovery of imiquimod, 26, which was developed as a topical agent and has been approved for the treatment of genital warts, actinic keratosis, and superficial basal cell carcinoma.