New insights into the rift to drift transition across the northeastern Nova Scotian margin from wide-angle seismic waveform inversion and reflection imaging

Author Posting. © American Geophysical Union, 2021. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Solid Earth 126(12), (2021): e2021JB022201, https://doi.org/10.1029/2021JB022201.Sparse wide-angle seismic profiling supported by coincident reflection imaging has been instrumental for advancing our knowledge about rifted margins. Nevertheless, features of critical importance for understanding rifting processes have been poorly resolved. We derive a high-resolution velocity model by applying full waveform inversion to the dense OETR-2009 wide-angle seismic profile crossing the northeastern Nova Scotian margin. We then create a coincident reflection image by prestack depth migrating the multichannel seismic data. This allows for the first detailed interpretation of the structures related to the final stages of continental breakup and incipient oceanic accretion at the Eastern North America Margin. Our interpretation includes a hyperextended continental domain overlying partially serpentinized mantle, followed by a 10-km-wide domain consisting of a continental block surrounded by layered and bright reflectors indicative of magmatic extrusions. A major fault, representing the continent-ocean boundary, marks a sharp seaward transition to a 16-km-wide domain characterized by smoother basement with chaotic reflectors, where no continental materials are present and a 3-km-thick embryonic oceanic crust overlying partially serpentinized mantle is created by the breakup magmatism. Further seaward, thin oceanic crust overlies the serpentinized mantle suggesting magma-poor oceanic spreading with variable magma supply as determined from variable basement topography, 2–4 km thick volcanic layer, and magnetic anomalies. Our results demonstrate that magmatism played an important role in the lithospheric breakup of the area crossed by the OETR-2009 profile. Considering that the northeastern Nova Scotian margin has been classified as amagmatic, large margin-parallel variations in magma supply likely characterize a single rift segment.H. Jian was supported by the Ocean Frontier Institute International Postdoctoral Fellowship at Dalhousie University and NSF grant OCE-2001012

Evaluation of the cytotoxic effects of sodium hypochlorite on human dental stem cells

Purpose: To investigate the influence of sodium hypochlorite (NaOCl) on human dental stem cell proliferation and differentiation.Method: Dental pulp stem cells (DPSCs), periodontal ligament stem cell (PDLSCs), and gingival mesenchymal stem cells (GMSCs) were treated with NaOCl. Cell viability was evaluated with cellular counting kit-8 (CCK8), and cellular adenosine triphosphate (ATP) levels were analyzed by bromodeoxyuridine (BrdU) incorporation and subsequent flow cytometry. Quantitative polymerase chain reaction (qPCR) and western blotting were performed to detect the expressions of differentiation markers.Results: The viability and ATP levels of all three stem cells types were impaired by NaOCl in a concentration- and time-dependent manners. However, the decrease ATP in GMSCs was less than the other two stem cell population (p < 0.05). NaOCl treatment significantly suppressed the proliferation of dental stem cells (p < 0.05). With regard to differentiation marker expression levels, the decrease in Stro-1 was greater in treatment groups when compared to control on Day 7, while increase in levels of dentin sialophosphoprotein (DSPP), bone sialoprotein (BSP), and osteocalcin (OC) was smaller (p < 0.05). The expressional changes of Stro-1, DSPP, BSP, and OC were more prominent in DPSMs and PDLSCs than in GMSCs.Conclusion: NaOCl dose-dependently impairs the viability, proliferation and differentiation of dental stem cells. Thus, its toxicity to dental stem cells needs to be considered in clinical application.Keywords: Dental stem cells, Sodium hypochlorite, Viability, Proliferation, Differentiatio

High-Resolution Boundary Detection for Medical Image Segmentation with Piece-Wise Two-Sample T-Test Augmented Loss

Deep learning methods have contributed substantially to the rapid advancement of medical image segmentation, the quality of which relies on the suitable design of loss functions. Popular loss functions, including the cross-entropy and dice losses, often fall short of boundary detection, thereby limiting high-resolution downstream applications such as automated diagnoses and procedures. We developed a novel loss function that is tailored to reflect the boundary information to enhance the boundary detection. As the contrast between segmentation and background regions along the classification boundary naturally induces heterogeneity over the pixels, we propose the piece-wise two-sample t-test augmented (PTA) loss that is infused with the statistical test for such heterogeneity. We demonstrate the improved boundary detection power of the PTA loss compared to benchmark losses without a t-test component

Rhodium-Catalyzed [4 + 3] Annulations of Sulfoximines with α,β-Unsaturated Ketones Leading to 1,2-Benzothiazepine 1‑Oxides

A Cp*Rh­(III) complex has been used as catalyst for the preparation of unprecedented 1,2-benzothiazepine 1-oxides by [4 + 3] cyclization of <i>N</i>H-sulfoximines with α,β-unsaturated ketones. For a wide range of substrates with various functional groups, moderate to good product yields were obtained

Rhodium-Catalyzed [4 + 3] Annulations of Sulfoximines with α,β-Unsaturated Ketones Leading to 1,2-Benzothiazepine 1‑Oxides

A Cp*Rh­(III) complex has been used as catalyst for the preparation of unprecedented 1,2-benzothiazepine 1-oxides by [4 + 3] cyclization of <i>N</i>H-sulfoximines with α,β-unsaturated ketones. For a wide range of substrates with various functional groups, moderate to good product yields were obtained

Seismic structure and magmatic construction of crust at the ultraslow‐spreading Southwest Indian Ridge at 50°28'E

We present a three-dimensional crustal structure of a magmatically robust segment of the ultraslow- spreading Southwest Indian Ridge at 50 degrees 28&apos; E based on tomographic inversions of an ocean bottom seismometer data set. Our results show an upper crustal low-velocity band in the axial zone, which is attributed to increased porosities due to active extensions, leading to anisotropy in the upper crust with a fast direction subperpendicular to the spreading direction. In the lower crust, the results reveal a round-shaped low-velocity anomaly at the segment center, indicative of high temperatures and/or a small amount of melt, suggestive of the presence of an axial magma chamber. At the midcrustal depth, an along-axis asymmetry is observed with respect to the segment center. While a small low-velocity anomaly indicates lateral magma redistribution toward the western segment end, the deep-penetrating low velocities and high velocity gradients toward the eastern end suggest that the crust is colder and contains a thicker fractured layer. This asymmetry occurs very close to the axial magma chamber (&lt; 5 km) and seems to be related to the fact that the oblique-spreading domain at the eastern end offsets the ridge axis by a larger distance than that at the western end. We suggest that an along-axis deep-penetrating hydrothermal circulation develops on the east side of the axial magma chamber, in response to the rapid change from orthogonal-to oblique-spreading domains and cools the crust.MOST grant [2012CB417301]; COMRA grant [DYXM-115-02-3-01]; NSF China grant [41030857]SCI(E)ARTICLE118-4212

Seismic structure and magmatic construction of crust at the ultraslow-spreading Southwest Indian Ridge at 50°28'E

International audienceWe present a three-dimensional crustal structure of a magmatically robust segment of the ultraslow-spreading Southwest Indian Ridge at 50°28'E based on tomographic inversions of an ocean bottom seismometer data set. Our results show an upper crustal low-velocity band in the axial zone, which is attributed to increased porosities due to active extensions, leading to anisotropy in the upper crust with a fast direction subperpendicular to the spreading direction. In the lower crust, the results reveal a round-shaped low-velocity anomaly at the segment center, indicative of high temperatures and/or a small amount of melt, suggestive of the presence of an axial magma chamber. At the midcrustal depth, an along-axis asymmetry is observed with respect to the segment center. While a small low-velocity anomaly indicates lateral magma redistribution toward the western segment end, the deep-penetrating low velocities and high velocity gradients toward the eastern end suggest that the crust is colder and contains a thicker fractured layer. This asymmetry occurs very close to the axial magma chamber (<5 km) and seems to be related to the fact that the oblique-spreading domain at the eastern end offsets the ridge axis by a larger distance than that at the western end. We suggest that an along-axis deep-penetrating hydrothermal circulation develops on the east side of the axial magma chamber, in response to the rapid change from orthogonal- to oblique-spreading domains and cools the crust

One Stitch Subconjunctival Suture - a new Suture Technique for Transconjunctival Vitrectomy

An efficient kinetic resolution of sulfoximines with enals was realized using chiral <i>N</i>-heterocyclic carbene (NHC) catalysts. The stereoselective amidation proceeds without additional acyl transfer agent. Both enantiomers of the sulfoximines can be obtained with excellent ee values (up to 99% ee and −97% ee, respectively). Performing the catalysis on a gram scale allowed using the recovered sulfoximine (+)-<b>1j</b> in an asymmetric synthesis of FXa inhibitor <b>F</b>