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Measurement of the neutrino-oxygen neutral-current quasielastic cross section using atmospheric neutrinos in the SK-Gd experiment
No full textWe report the first measurement of the atmospheric neutrino-oxygen neutral-current quasielastic (NCQE) cross section in the gadolinium-loaded Super-Kamiokande (SK) water Cherenkov detector. In June 2020, SK began a new experimental phase, named SK-Gd, by loading 0.011% by mass of gadolinium into the ultrapure water of the SK detector. The introduction of gadolinium to ultrapure water has the effect of improving the neutron-tagging efficiency. Using a 552.2 day dataset from August 2020 to June 2022, we measure the NCQE cross section to be 0.74±0.22(stat)-0.15+0.85(syst)×10-38 cm2/oxygen in the energy range from 160 MeV to 10 GeV, which is consistent with the atmospheric neutrino-flux-averaged theoretical NCQE cross section and the measurement in the SK pure-water phase within the uncertainties. Furthermore, we compare the models of the nucleon-nucleus interactions in water and find that the binary cascade model and the Liège intranuclear cascade model provide a somewhat better fit to the observed data than the Bertini cascade model. Since the atmospheric neutrino-oxygen NCQE reactions are one of the main backgrounds in the search for diffuse supernova neutrino background (DSNB), these new results will contribute to future studies - and the potential discovery - of the DSNB in SK.11Nsciescopu
A unified half-integral Erdős–Pósa theorem for cycles in graphs labelled by multiple abelian groups
No full textErdős and Pósa proved in 1965 that there is a duality between the maximum size of a packing of cycles and the minimum size of a vertex set hitting all cycles. Such a duality does not hold if we restrict to odd cycles. However, in 1999, Reed proved an analogue for odd cycles by relaxing packing to half-integral packing. We prove a far-reaching generalisation of the theorem of Reed; if the edges of a graph are labelled by finitely many abelian groups, then there is a duality between the maximum size of a half-integral packing of cycles whose values avoid a fixed finite set for each abelian group and the minimum size of a vertex set hitting all such cycles. A multitude of natural properties of cycles can be encoded in this setting, for example, cycles of length at least (Formula presented.), cycles of length (Formula presented.) modulo (Formula presented.), cycles intersecting a prescribed set of vertices at least (Formula presented.) times and cycles contained in given (Formula presented.) -homology classes in a graph embedded on a fixed surface. Our main result allows us to prove a duality theorem for cycles satisfying a fixed set of finitely many such properties. © 2024 The Authors. Journal of the London Mathematical Society is copyright © London Mathematical Society.11Nsciescopu
NiH-catalyzed C-N bond formation: insights and advancements in hydroamination of unsaturated hydrocarbons
No full textThe formation of C-N bonds is a fundamental aspect of organic synthesis, and hydroamination has emerged as a pivotal strategy for the synthesis of essential amine derivatives. In recent years, there has been a surge of interest in metal hydride-catalyzed hydroamination reactions of common alkenes and alkynes. This method avoids the need for stoichiometric organometallic reagents and overcomes problems associated with specific organometallic compounds that may impact functional group compatibility. Notably, recent developments have brought to the forefront olefinic hydroamination and hydroamidation reactions facilitated by nickel hydride (NiH) catalysis. The inclusion of suitable chiral ligands has paved the way for the realization of asymmetric hydroamination reactions in the realm of olefins. This review aims to provide an in-depth exploration of the latest achievements in C-N bond formation through intermolecular hydroamination catalyzed by nickel hydrides. Leveraging this innovative approach, a diverse range of alkene and alkyne substrates can be efficiently transformed into value-added compounds enriched with C-N bonds. The intricacies of C-N bond formation are succinctly elucidated, offering a concise overview of the underlying reaction mechanisms. It is our aspiration that this comprehensive review will stimulate further progress in NiH-catalytic techniques, fine-tune reaction systems, drive innovation in catalyst design, and foster a deeper understanding of the underlying mechanisms. This review highlights recent progress in NiH-catalyzed hydroamination, focusing on its application to a variety of alkenes and alkynes.11Nsciescopu
Inter-model robustness of the forced change of the ENSO-Indian Summer Monsoon Teleconnection
No full textConcerning the robustness of predicting the forced response of the El Niño—Southern Oscillation-Indian summer monsoon (ENSO-ISM) teleconnection based on 9 CMIP-class models, we come to distinguish three time periods. (1) In the late 20th century, the trend was insignificant in most models, which does not permit a statement on robustness in this period. Thus the weakening of the teleconnection reported from the observational data might not be truly forced. (2) Furthermore, we find it typical that under global warming in the first part of the 21st century, the teleconnection is strengthening or non-decreasing. This considerable inter-model robustness is owed to an increasing ENSO variability as well as coupling strength. (3) At the end of the 21st century, however, under strong forcing, the teleconnection change is not robustly modeled: the ENSO variability change is not projected robustly across models, either with respect to the start or the rate of the ENSO variance decline, competing this time with an increase of the coupling strength. The difference in the projected coupling coefficient between models is mainly attributed to the disagreement in the projected ENSO-induced changes in the regional Hadley cell and SST patterns over the ISM domain, despite the agreement on the projected eastward shift of the Walker cell over the Pacific Ocean. © 2024, The Author(s).11Nscopu
Highly Selective Detection of Large-Sized Chemical Warfare Agents via Interface-Controlled Diffusion Channels of Graphene Oxide Frameworks
No full textChemical warfare agents (CWAs), which contain organophosphonate groups, are highly toxic compounds designed to inflict harm and death. They have been utilized in both wartime conflicts and acts of terrorism. In response to the persistent threat of CWAs, various organic receptors and high-surface-area matrix materials have been extensively researched. This study investigates how the interlayer spacing of the graphene oxide framework (GOF) with receptors affects its ability to detect a large-sized simulant of CWAs, dimethyl methylphosphonate (DMMP). The interlayer spacing was controlled by the concentration and length of diamine spacers, varying from 7.8 to 10.5 Å. Quartz-crystal microbalance (QCM) and surface acoustic wave (SAW) were employed to conduct a cross-investigation into the sensitivity and selectivity of GOF. The enlarged diffusion channel width of the optimized GOF allows for easy accessibility of DMMP, resulting in over 99% selectivity compared to interfering volatile organic compounds (VOCs), and an 8.7-fold increase in adsorption sensitivity. © 2023 American Chemical Society.11Nsciescopu
APP-C31: An Intracellular Promoter of Both Metal-Free and Metal-Bound Amyloid-β40 Aggregation and Toxicity in Alzheimer's Disease
No full textIntracellular C-terminal cleavage of the amyloid precursor protein (APP) is elevated in the brains of Alzheimer's disease (AD) patients and produces a peptide labeled APP-C31 that is suspected to be involved in the pathology of AD. But details about the role of APP-C31 in the development of the disease are not known. Here, this work reports that APP-C31 directly interacts with the N-terminal and self-recognition regions of amyloid-β40 (Aβ40) to form transient adducts, which facilitates the aggregation of both metal-free and metal-bound Aβ40 peptides and aggravates their toxicity. Specifically, APP-C31 increases the perinuclear and intranuclear generation of large Aβ40 deposits and, consequently, damages the nucleus leading to apoptosis. The Aβ40-induced degeneration of neurites and inflammation are also intensified by APP-C31 in human neurons and murine brains. This study demonstrates a new function of APP-C31 as an intracellular promoter of Aβ40 amyloidogenesis in both metal-free and metal-present environments, and may offer an interesting alternative target for developing treatments for AD that have not been considered thus far. © 2023 The Authors. Advanced Science published by Wiley-VCH GmbH.11Ysciescopu
Soft bioelectronics for the management of cardiovascular diseases
No full textThe motions of the heart are regulated by electrophysiological signals, which can be monitored and altered by bioelectronic devices for the diagnosis and treatment of cardiovascular diseases. In particular, soft bioelectronic devices, composed of deformable and conductive materials, can be implanted or designed as wearable devices to enable conformal contact with heart tissue or the skin for real-time and precise diagnosis and treatment. In this Review, we discuss the design and materials of soft bioelectronic devices, highlighting their advantages, as compared with rigid bioelectronic devices, in cardiovascular disease management. We examine the engineering and applications of soft implantable bioelectronics, including cardiac mapping devices, cardiac stimulation devices and mechanically assisting devices, as well as wearable soft bioelectronics, such as blood oxygen saturation sensors, heart monitoring devices and transdermal drug delivery systems. Finally, we outline technical challenges and future opportunities for the clinical application of soft bioelectronic devices, such as a wireless power supply, optogenetic control of cardiac motion, bioadhesives for device?tissue interfaces and artificial intelligence-assisted data analysis.11Nothe
Random-singlet-like state emergent in s = 5/2 frustrated cubic lattice
No full textWe employ thermodynamic and electron spin resonance (ESR) techniques to elucidate the effects of quenched disorder on a ground state of s= 5 / 2 frustrated cubic antiferromagnet La 3 Sb 3 Mn 2 O 14 . We observe the development of multiple ESR lines for temperatures below 80 K. Concomitantly, the ESR linewidth exhibits a power-law increase, accompanied by an intriguing shift in resonance fields. These observations point to the occurrence of inhomogeneous magnetism. Additionally, ac magnetic susceptibility and magnetization data obey a scaling relation of χ′(H, T) and M(H, T) in μBH/ kBT with the scaling exponent α= 0.53 . This scaling behavior alludes to the formation of a random-singlet-like state and the presence of abundant low-lying excitations. Our results highlight the concerted interplay of strong disorder and frustration to stabilize a putative random-singlet state even in classical and high-dimensional spin systems. © 2024, The Korean Physical Society.11Nscopuskc
Omicron BA.2 breakthrough infection elicits CD8+ T cell responses recognizing the spike of later Omicron subvariants
No full textHere, we examine peripheral blood memory T cell responses against the SARS-CoV-2 BA.4/BA.5 variant spike among vaccinated individuals with or without Omicron breakthrough infections. We provide evidence supporting a lack of original antigenic sin in CD8+ T cell responses targeting the spike. We show that BNT162b2-induced memory T cells respond to the BA.4/BA.5 spike. Among individuals with BA.1/BA.2 breakthrough infections, IFN-γ-producing CD8+ T cell responses against the BA.4/BA.5 spike increased. In a subgroup with BA.2 breakthrough infections, IFN-γ-producing CD8+ T cell responses against the BA.2-mutated spike region increased and correlated directly with responses against the BA.4/BA.5 spike, indicating that BA.2 spike-specific CD8+ T cells elicited by BA.2 breakthrough infection cross-react with the BA.4/BA.5 spike. We identified CD8+ T cell epitope peptides that are present in the spike of BA.2 and BA.4/BA.5 but not the original spike. These peptides are fully conserved in the spike of now-dominant XBB lineages. Our study shows that breakthrough infection by early Omicron subvariants elicits CD8+ T cell responses that recognize epitopes within the spike of newly emerging subvariants.11Nsciescopu
Measuring Nonlocal Brane Order with Error-Corrected Quantum Gas Microscopes
No full textExotic quantum many-body states, such as Haldane and spin liquid phases, can exhibit remarkable features like fractional excitations and non-Abelian statistics and offer new understandings of quantum entanglement in many-body quantum systems. These phases are classified by nonlocal correlators that can be directly measured in atomic analog quantum simulating platforms, such as optical lattices and Rydberg atom arrays. However, characterizing these phases in large systems is experimentally challenging because they are sensitive to local errors like atom loss, which suppress its signals exponentially. Additionally, protocols for systematically identifying and mitigating uncorrelated errors in analog quantum simulators are lacking. Here, we address these challenges by developing an error-correction method for large-scale neutral atom quantum simulators using optical lattices. Our error-correction method can distinguish correlated particle-hole pairs from uncorrelated holes in the Mott insulator. After removing the uncorrelated errors, we observe a dramatic improvement in the nonlocal parity correlator and find the perimeter scaling law. Furthermore, the error model provides a statistical estimation of fluctuations in site occupation, from which we measure the generalized brane correlator and confirm that it can be an order parameter for Mott insulators in two dimensions. Our work provides a promising avenue for investigating and characterizing exotic phases of matters in large-scale quantum simulators. © 2024 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the https://creativecommons.org/licenses/by/4.0/Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.11Nscopu