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Intraplate earthquakes induced by anthropogenic fluid injection present unexpected seismic risk to previously quiescent or low seismicity-rate regions. Despite many studies of induced seismicity, there are relatively few with detailed openly accessible constraints on the interaction between seismic sources and subsurface structures. In this study of the Raton Basin, we refine source observations from a dense nodal array and constrain basin structure using teleseismic receiver functions. The cross-correlation-based relocated hypocentres and a new set of focal mechanisms light up active fault segments and show clear spatiotemporal patterns. The geometric complexity of reactivated fault clusters appears greatest near higher rate injection wells. Simpler normal fault structure is found farther from injection wells and near abrupt structural transitions suggested by receiver functions. While less induced seismicity in the crystalline basement is expected when injection is >1 km from the top of the basement (like Raton), our receiver function analysis identified a basin thickness ~3 km beneath the nodal array and lateral variations in sedimentary structures. Our results explain potential fluid connectivity between the injection depths focused at ~1–1.5 km below the surface and basement fault activity that begins at ~3 km and reaches peak activity at ~4–8 km depths. This article is part of the theme issue 'Induced seismicity in coupled subsurface systems'. [ABSTRACT FROM AUTHOR]

Introduction: In December 2019, the COVID-19 pandemic highlighted the urgent need for rapid collaboration, research, and interventions. International research collaborations foster more significant responses to rapid global changes by enabling international, multicentre research, decreasing biases, and increasing study validity while reducing overall research time and costs. However, there has been low uptake of collaborative research by African institutions and individuals. Aim: To systematically review facilitating factors and challenges to collaborative surgical research studies conducted in Africa. Methodology: A meta-research review using PubMed®/MEDLINE and Embase on surgical collaboration in Africa from 1st of January 2011 to 31st of September 2021 in accordance to PRISMA guidelines. Surgical studies by collaborative groups involving African authors and sites were included (55 papers). Data on the study period, geographical regions, and research scope, facilitating factors, and challenges were extracted from the studies retrieved from the search. Results: Most of the collaborations in Africa occurred with European institutions (76%). Of the 54 African countries, 63% (34/54) participated in surgical collaborations. The highest collaboration frequency occurred in South Africa (11%) and Nigeria (8%). However, most publications originated from Eastern Africa (43%). Leveraging synergies between high- and low- to middle-income countries (LMICs), well-defined structures, and secure data platforms facilitated collaboration. However, the underrepresentation of collaborators from LMICs was a significant challenge. Conclusion: Available literature provides critical insights into the facilitating factors and challenges of research collaboration with Africa. However, there is a need for a detailed prospective study to explore the themes highlighted further. Systematic review registration: PROSPERO 2022 CRD42022352115. [ABSTRACT FROM AUTHOR]

Pulmonary alveolar proteinosis (PAP) is a rare interstitial lung disease. The ideal therapy to clear the accumulated lipoproteinaceous material is whole lung lavage (WLL). While there have been few cases of PAP in Sub-Saharan Africa, none have been reported in Kenya. We describe a case of a 36-year-old Kenyan lady with progressive dyspnea, cough, tachypneic, and respiratory crackles at presentation. A high-resolution computed tomography (HRCT) scan showed a "crazy-paving" pattern and a transbronchial lung biopsy revealed periodic acid-Schiff positive exudates. She was diagnosed with PAP and WLL was performed. She was discharged after 3 days with marked improvement. Unfortunately, she succumbed intraoperatively during the WLL of the contralateral lung 6 weeks later and a postmortem revealed widespread proteinosis. This case illustrates the diagnosis and treatment of a rare lung disease by WLL in a resource-limited setting with the assistance of a multidisciplinary team. [ABSTRACT FROM AUTHOR]

We examine the coseismic influence of the 5 July 2019, MW7.1 Ridgecrest and the 24 June 2020 MW5.8 Owens Lake earthquakes on rockfall distributions in two undisturbed high-altitude areas of the southern Sierra Nevada Mountains, California, USA. These events occurred within the geologically recent (<2 Mya) Walker Lane/eastern California shear zone. While both study areas are characterized as plutonic, the Owens Lake event largely affected terrain that was formerly glaciated and oversteepened while the Ridgecrest event affected non-glaciated terrain. Our inventory of rockfall locations was derived from analysis of Sentinel-2 images acquired just prior to and immediately after the events. This difference mapping approach using readily-available Sentinel-2 imagery allows for rapid rockfall and landslide mapping. GIS analysis shows that even though the total area assessed for both earthquakes was similar (~1500 km2), the significantly lower magnitude Owens Lake event produced nearly twice as many (102) mappable rockslides as the significantly stronger Ridgecrest event (58), a difference likely due to slope oversteepening in the formerly glaciated area. Significant seismic amplification by topography and reactivation of preexisting failures was apparent for both areas. Inclusion of these factors may improve failure predictions and rockfall probability estimation. [ABSTRACT FROM AUTHOR]

We conduct a high‐resolution teleseismic receiver function investigation of the subducting plate interface within the Alaskan forearc beneath Kodiak Island using data collected as part of the Alaska Amphibious Community Seismic Experiment in 2019. The Kodiak node array consisted of 398 nodal geophones deployed at ∼200–300 m spacing on northeastern Kodiak Island within the southern asperity of the 1964 Mw9.2 Great Alaska earthquake. Receiver function images at frequencies of 1.2 and 2.4 Hz show a coherent, slightly dipping velocity increase at ∼30–40 km depth consistent with the expected slab Moho. In contrast to studies within the northern asperity of the 1964 rupture, we find no evidence for a prominent low‐velocity layer above the slab Moho thick enough to be resolved by upgoing P‐to‐S conversions. These results support evidence from seismicity and geodetic strain suggesting that the 1964 rupture connected northern (Kenai) and southern (Kodiak) asperities with different plate interface properties. Plain Language Summary: We use 398 portable seismometers that were deployed as part of the Alaska Amphibious Community Seismic Experiment to image the boundary between the subducting Pacific plate and the base of the North American plate. The seismometers, spaced ∼200–300 m apart, were stationed on Kodiak Island in 2019 within the southern rupture area of the 1964 Mw9.2 Great Alaska earthquake. We analyze conversions from compressional to shear waves from distant earthquakes to understand the conditions of the plate interface. Our results show a dipping velocity increase at ∼30–40 km depth at the expected location of the Pacific slab crust‐mantle boundary. In contrast to prior results from the northern 1964 rupture zone, we do not find a low‐velocity layer on the subducting plate. Our results indicate that the 1964 rupture connected segments of the Alaskan subduction zone with different plate interface properties. Key Points: We present receiver function imaging from a dense three‐component nodal array deployment on Kodiak Island above the subducting Pacific PlateA clear slab Moho conversion is found but, in contrast to the Kenai Peninsula, there is no coherent low‐velocity layer atop the slabThe 1964 Great Alaska Earthquake ruptured across structural segments with different plate interface properties [ABSTRACT FROM AUTHOR]

The North Basin of the Malawi Rift is an active, early‐stage rift segment that provides the opportunity to quantify cumulative and recent faulting patterns in a young rift, assess contributions of intrarift faults to accommodating rift opening, and examine controls on spatial patterns of faulting. Multichannel seismic reflection data acquired in Lake Malawi (Nyasa) in 2015 together with legacy multichannel seismic data image a system of synthetic intrarift faults within this border‐fault‐bounded, half‐graben basin. A dense wide‐angle seismic reflection/refraction dip profile acquired with lake bottom seismometer data constrains sediment velocities that are used to convert fault throws from travel time to depth. Observed extension on intrarift faulting in the northern and central parts of the North Basin is approximately twice what would be predicted for hanging wall flexure, implying that the intrarift faults contribute to basin opening. The cumulative throw on intrarift faults is higher in the northern part of the rift segment than the south and is anticorrelated with throw on the border fault, which is largest in the southern part of the North Basin. This change in faulting coincides with a change in the orientation of the North Basin from a N‐S trend in the south to a NNW‐SSE trend in the north. We infer that the distribution of extension is influenced by rift orientation with respect to the regional extension direction. Almost all intrarift faults substantially offset late Quaternary synrift sediments, suggesting they are likely active and need to be considered in hazard assessments. Key Points: Intrarift faulting contributes to rift openingThe style and amount of rift faulting change along strike in North BasinNearly all intrarift faults have been active in the last ~75 kyr [ABSTRACT FROM AUTHOR]

Three new derivatives of 1 -(phenylsulfonyl)indole : 3-nitro-1-(phenylsulfonyl)-1 H-indol-2-amine (I): CHNOS; N-( tert-butyl)-3-nitro-1-(phenylsulfonyl)-1 H-indol-2-amine (II): CHNOS and tert-butyl 4-(phenylsulfonyl)-(1; Pelkey, Gribble, Tetrahedron Lett 38:5603-5606, 1997; 3)triazolo[4,5- b]indole-1(4 H)-carboxylate (III): CHNOS, have been synthesized and their structures determined by single crystal X-ray crystallography. (I), CHNOS, is triclinic with space group P-1 and cell constants: a = 7.7394(8) Å, b = 12.5826(11) Å, c = 14.7280(13) Å, α = 77.259(8)°, β = 75.885(8)°, γ = 79.342(8)°, V = 1343.6(2) Å, Z = 4. (II), CHNOS, is monoclinic with space group P2/c and cell constants: a = 16.0499(5) Å, b = 12.0196(4) Å, c = 9.7866(4) Å, β = 104.879(4)°, V = 1824.67(12) Å, Z = 4. (III), CHNOS, is triclinic with space group P-1 and cell constants: a = 9.0391(8) Å, b = 10.3429(12) Å, c = 10.8145(11) Å, α = 75.870(9)°, β = 71.489(9)°, γ = 88.111(8)°, V = 928.64(17) Å, Z = 2. All three compounds have the same indole nitrogen phenylsulfonyl substituent. In the crystals, the dihedral angle between the mean planes of the pyrrolyl groups of the indole ring and phenylsulfonyl groups are 86.0(8) ( IA) or 83.5(4) (IB), and 85.0(6) (III), forming an L-shaped molecule, while in (II) it is 52.9(5), forming a V-shaped molecule due in part to the puckering of the pyrrolyl ring from the nonplanar indole group. Additionally, the DFT frontier molecular orbitals of each compound are displayed and correlation between the calculated molecular orbital energies (eV) for the surfaces of the frontier molecular orbitals to the electronic excitation transitions from the absorption spectra of each compound have been proposed. Graphical Abstract: Synthesis, Crystal Structures, Density Functional Theory (DFT) Calculations and Molecular Orbital Calculations of three new derivatives of 1-(phenylsulfonyl)indole: 3-nitro-1-(phenylsulfonyl)-1H-indol-2-amine (I): C14H11N¬3O4S; N-(tert-butyl)-3-nitro-1-(phenylsulfonyl)-1H-indol-2-amine (II): C18H19N3O4S and tert-butyl 4-(phenylsulfonyl)-[1,2,3]triazolo[4,5-b]indole-1(4H)-carboxylate (III): C19H18N4O4S. [ABSTRACT FROM AUTHOR]

Vibrio cholerae is responsible for the diarrheal disease cholera that infects millions of people worldwide. While vaccines protecting against cholera exist, and oral rehydration therapy is an effective treatment method, the disease will remain a global health threat until long-term solutions such as improved sanitation and access to clean water become widely available. Because of this, there is a pressing need for potent therapeutics that can either mitigate cholera symptoms, or act prophylactically to prevent the virulent effects of a cholera infection. Here we report the design, synthesis, and characterization of a set of compounds that bind and inhibit ToxT, the transcription factor that directly regulates the two primary V. cholerae virulence factors. Using the folded structure of the monounsaturated fatty acid observed in the X-ray structure of ToxT as a template, we designed ten novel compounds that inhibit the virulence cascade to a greater degree than any known inhibitor. Our findings provide a structural and functional basis for the development of viable antivirulence therapeutics that combat cholera and, potentially, other forms of bacterial pathogenic disease. [ABSTRACT FROM AUTHOR]