Polarity Transition Research Articles

Ultra-sensitive CO2 switchable low temperature transition mixture for intensified retrieval of oily waste

One of the challenge in the remediation of contaminated soil by solvent washing is the retrieval of total petroleum hydrocarbons (TPH) and solvents. Herein, a CO2 switchable hydrophobic low temperature transition mixture ([DPA][EL]) composed of ethyl lactate (EL) and dipropylamine (DPA) is proposed, accompanied by a proof-of-concept for contaminated soil washing. The path and energy of hydrogen bond interactions in [DPA][EL] were revealed by the quantum chemical calculation using the quantum theory of atoms in molecule. [DPA][EL] achieved a thorough CO2-induced polarity and hydrophobicity transition undergoing an incomplete CO2 absorption that results in the partial formation of carbonate and carbamate. [DPA][EL] was regenerated after the removal of CO2 by heating at 85 °C for 2 min. Thanks to this peculiarity, the time required for hydrophobicity transition was 197 times shorter than that of the typical CO2 switchable hydrophobic solvent, N,N-dimethylcyclohexylamine. The polarity of [DPA][EL], quantified by the normalized polarity energy, increased by 346.69 % after the introduction of CO2 because of the synergistic effect of water. This ultra-sensitive transition behavior intensified the CO2-induced separation of oily compounds, e.g., kerosene and crude oil. The conceptual usage of [DPA][EL] in the contaminated soil washing was demonstrated. The TPH content of contaminated soil decrease from 8.27 % to 0.31 % by [DPA][EL] washing through tailoring the molar ratio of DPA to EL in [DPA][EL], temperature, and [DPA][EL] to contaminated soil ratio (L/S, mL/g). [DPA][EL] whose composition possesses different polarities compensated for the poor solubility of single solvents towards TPH, thereby improving the washing efficiency of contaminated soil. Afterwards, TPH was separated upon triggered by CO2/water in 2 min, and 91.33 % of [DPA][EL] was subsequently regenerated at 85 °C in 2 min.

Polarization photodetectors with configurable polarity transition enabled by programmable ferroelectric-doping patterns

Advances in symmetry-breaking engineering of heterointerfaces for optoelectronic devices have garnered significant attention due to their immense potential in tunable moiré quantum geometry and enabling polarization light detection. Despite several proposed approaches to breaking the symmetry of low-dimensional materials, there remains a lack of universal methods to create materials with prominent polarization detection capabilities. Here, we introduce a reliable strategy for manipulating the symmetry of low-dimensional materials through a programmable ferroelectric-doping patterns technique. This method introduces a spontaneous photocurrent and enables the detection of linearly polarization light in isotropic 2H-MoTe2. The 2H-MoTe2 photodetector exhibits a significant short-circuit photocurrent intensity (Jsc = 29.9 A/cm2) and open-circuit voltage Voc of 0.12 V ( ~ 3 × 105 V/cm). Under a specific bias, the polarization ratio transitions from 1 to ∞/−∞, shifting from a positive state (unipolar regime) to a negative state (bipolar regime). These findings underscore the potential of ferroelectric-doping patterns as a promising approach to creating composite materials with artificial bulk photovoltaic effect and achieving high-performance polarization light detection.

ICAM‐1‐Expressing Extracellular Vesicles Enable Sequential Delivery Barrier‐Breaking and Microenvironment Modulating for Glioblastoma Stem Cell Inhibition

AbstractGlioma stem‐like cell (GSC) inhibition is a promising strategy for glioblastoma therapy. However, it is hampered by two main obstacles: first, delivery barriers, including the blood–brain barrier (BBB) and deep tumor‐penetrating obstacles, hinder sufficient drug accumulation in GSCs that often reside in hypoxic niches deep in glioblastoma; second, hypoxia and the immunosuppressive tumor microenvironment (TME) limit the therapeutic responses of GSC inhibition strategies. An intercellular cell adhesion molecule 1 (ICAM‐1)‐expressing M1 macrophage‐derived small extracellular vesicles loaded with a complex of bovine serum albumin, MnO2, and the small‐molecule inhibitor PTC209 (IsEV‐BMP) is constructed to achieve sequential barrier‐breaking delivery and simultaneous TME modulation to boost GSC inhibition. ICAM‐1 facilitates endothelial transcytosis‐mediated BBB crossing, microglial transcytosis‐mediated deep tumor penetration, and internalization of IsEV‐BMPs in GSCs. Hypoxia alleviation inhibits the binding of hypoxia‐inducible factor 1α (HIF‐1α) to hypoxia‐responsive elements on the gene promoters of cancer stem cell‐related markers and CD47 in GSCs, thereby improving PTC209 sensitivity and immune phagocytosis of GSCs. IsEV‐BMP achieves simultaneous microglial polarity transition and immuno‐microenvironmental modulation during microglial transcytosis‐mediated deep tumor penetration. This study provides a strategy to overcome the sequential delivery barrier for effective glioblastoma treatment.

Ab initio electronic absorption spectra of para-nitroaniline in different solvents: Intramolecular charge transfer effects.

Intramolecular charge transfer (ICT) effects of para-nitroaniline (pNA) in eight solvents (cyclohexane, toluene, acetic acid, dichloroethane, acetone, acetonitrile, dimethylsulfoxide, and water) are investigated extensively. The second-order algebraic diagrammatic construction, ADC(2), ab initio wave function is employed with the COSMO implicit and discrete multiscale solvation methods. We found a decreasing amine group torsion angle with increased solvent polarity and a linear correlation between the polarity and ADC(2) transition energies. The first absorption band involves π → π* transitions with ICT from the amine and the benzene ring to the nitro group, increased by 4%-11% for different solvation models of water compared to the vacuum. A second band of pNA is characterized for the first time. This band is primarily a local excitation on the nitro group, including some ICT from the amine group to the benzene ring that decreases with the solvent polarity. For cyclohexane, the COSMO implicit solvent model shows the best agreement with the experiment, while the explicit model has the best agreement for water.

Polarity transitions of narrow bipolar events in thundercloud tops reaching the lower stratosphere

Blue corona discharges are often generated in thunderclouds penetrating into the stratosphere and are the optical manifestation of narrow bipolar events (NBEs) observed in radio signals. While their production appears to depend on convection, the cause and nature of such discharges are not well known. Here we show the observations by a lightning detection array of unusual amounts of 982 NBEs during a tropical storm on the coastline of China. NBEs of negative polarity are predominantly observed at the cloud top reaching the stratosphere, and positive NBEs are primarily at lower altitudes. We find that the dominant polarity changes with the typical time of development of thunderstorm cells, suggesting that the polarity depends on the phase of the storm cells. Furthermore, we find that the lightning jump of negative NBEs is associated with above-anvil cirrus plumes of ice crystals and water vapor in the lower stratosphere. We propose that variations in updrafts induce changes in the altitude and charge concentrations of the cloud layers, which lead to the polarity transition. Our results have implications for studies of the chemical perturbations of greenhouse gas concentrations by corona discharges at the tropopause.

Magnetostratigraphy and rock magnetic studies on the Cretaceous‐Paleogene transition strata along the Um Sohryngkew River, Therriaghat, Meghalaya, India

A combination of magnetic polarity and rock magnetic analysis on the well‐documented section of the Um Sohryngkew River (USR) in the south Shillong Plateau, NE India, produced a sharp reversal marking the C29r‐C29n geomagnetic polarity transition at approximately 65.688 Ma. The rock magnetic studies indicate ferrimagnetic dominant mineralogy with abundance of SSD grains, with an anomalous peak in susceptibility coinciding with Ir‐rich limonitic layer. The magnetic reversal occurs precisely 61 m above the Ir‐rich distinct in situ limonitic layer, indicating that the C29r‐C29n geomagnetic reversal post‐dates the widely accepted Ir‐anomaly based K‐Pg boundary by approximately 355 Ka. Furthermore, the rock magnetic studies indicate its frequency dependence coinciding with the Ir‐rich limonitic layer suggesting a possible dust/aerosol source, while akaganéite is reported from the interval approximately 1 m below peak susceptibility, indicating signature of Deccan volcanism. This study infers the completeness of the USR section with a high rate of sedimentation of approximately 17 cm/ka among the marine K‐Pg boundary sections in the world.

In-Sublattice Carrier Transition Enabled Polarimetric Photodetectors with Reconfigurable Polarity Transition.

Miniaturized polarimetric photodetectors based on anisotropic two-dimensionalmaterials attract potential applications in ultra-compact polarimeters. However, these photodetectors are hindered by the small polarization ratio values and complicated artificial structures. Here, a novel polarization photodetector based on in-sublattice carrier transition in the CdSb2Se3Br2/WSe2 heterostructure, with a giant and reconfigurable PR value, is demonstrated. The unique periodic sublattice structure of CdSb2Se3Br2 features an in-sublattice carrier transition preferred along Sb2Se3 chains. Leveraging on the in-sublattice carrier transition in the CdSb2Se3Br2/WSe2 heterostructure, gate voltage has an anisotropic modulation effect on the band alignment of heterostructure along sublattice. Consequently, the heterostructure exhibits a polarization-tunable photo-induced threshold voltage shift, which provides reconfigurable PR values from positive (unipolar regime) to negative (bipolar regime), covering all possible numbers (1→+∞/-∞→-1). Using this anisotropic photovoltaic effect, gate-tunable polarimetric imaging is successfully implemented. This work provides a new platform for developing next-generation highly polarimetric optoelectronics.

Role of Lipocalin-2 in N1/N2 Neutrophil Polarization After Stroke.

Neutrophils and Lipocalin-2 (LCN2) play pivotal roles in cerebral ischemiareperfusion (I/R) injury. However, their contribution is not fully clarified. This study aimed to explore the role of LCN2 and its association with neutrophil polarization in I/R injury. A mouse model of middle cerebral artery occlusion (MCAO) was used to induce cerebral ischemia. LCN2mAb was administered 1 h and Anti-Ly6G was administered for 3d before MCAO. The role of LCN2 in the polarity transition of neutrophils was explored using an in vitro HL-60 cell model. LCN2mAb pretreatment had neuroprotective effects in mice. The expression of Ly6G was not significantly different, but the expression of N2 neutrophils was increased. In the in vitro study, LCN2mAb-treated N1-HL-60 cells induced N2-HL-60 polarization. LCN2 may affect the prognosis of ischemic stroke by mediating neutrophil polarization.

Gate‐Modulated Polarity Transition and Polarization‐Sensitive Photodetection Enabled by Sandwiching Anisotropic GeSe in vdW Heterojunction

AbstractThe ability to modulate the polarity of carrier transport and photo‐response in assembled heterostructure devices remains a huge challenge for the development of multifunctional optoelectronics. Herein, a polarity‐switchable and polarization‐sensitive photodetector is developed based on a van der Waals (vdW) MoTe2/GeSe/MoS2 sandwich heterostructure. By varying the gate voltage, an anti‐bipolar transfer characteristic is obtained with significant peak‐valley current ratio (PVCR) exceeding 104, showing the extraordinary potential to realize electronic functions in logic circuits. Under 635 nm laser irradiation, the device exhibits a gate‐controlled polarity transition of photocurrent, namely, the sign reversal of photocurrent occurs by changing the gate voltage. Furthermore, the device achieves broadband photovoltaic effect and high photodetection performance with responsivity (R) of 723 mA·W−1, noise spectral density (Sn) of 1 fA Hz−1/2, and specific detectivity (D*) of 2.3×1012 Jones in the absence of external bias, which greatly outperforms the MoTe2/MoS2 device. Leveraging the in‐plane anisotropic structure of GeSe, the device is also endowed with an additional capability of polarization‐sensing for linearly polarized laser, possessing a high polarization ratio (PR) value of 11.2. Thus, this work proposes an effective and facile strategy to realize the gate‐modulated polarity transition and polarization‐sensitive photodetection, offering a broad perspective for multifunctional integrated applications.

Self-similarity of the dipole–multipole transition in rapidly rotating dynamos

The dipole–multipole transition in rapidly rotating dynamos is investigated through the analysis of forced magnetohydrodynamic waves in an unstably stratified fluid. The focus of this study is on the inertia-free limit applicable to planetary cores, where the Rossby number is small not only on the core depth but also on the length scale of columnar convection. By progressively increasing the buoyant forcing in a linear magnetoconvection model, the slow magnetic–Archimedean–Coriolis (MAC) waves are significantly attenuated so that their kinetic helicity decreases to zero; the fast MAC wave helicity, on the other hand, is practically unaffected. In turn, polarity reversals in low-inertia spherical dynamos are shown to occur when the slow MAC waves disappear under strong forcing. Two dynamically similar regimes are identified – the suppression of slow waves in a strongly forced dynamo and the excitation of slow waves in a moderately forced dynamo starting from a small seed field. While the former regime results in polarity reversals, the latter regime produces the axial dipole from a chaotic multipolar state. For either polarity transition, a local Rayleigh number based on the mean wavenumber of the energy-containing scales bears the same linear relationship with the square of the peak magnetic field measured at the transition. The self-similarity of the dipole–multipole transition can place a constraint on the Rayleigh number for polarity reversals in the Earth.

Photoelectrochemical signal polarity transition mediated by quercetin for the detection of neuron-specific enolase.

A photoelectrochemical (PEC) biosensor with a wide linear detection range was developed for the sensitive detection of neuron-specific enolase (NSE), which was achieved by applying a photocurrent polarity transition strategy mediated by quercetin. The coupling reaction between Cr(VI) and quercetin drives the signal polarity from anodic to cathodic. When only quercetin is present in the test solution, photogenerated electrons are transferred to the electrode to generate anodic photocurrent. However, in the presence of the target, the signal probe released Cr(VI), which interacted with quercetin, and the electron transfer direction was changed to achieve signal polarity conversion. Meanwhile, protoporphyrin-sensitized Bi:SrTiO3 nanocubes were used as matrix photoactive materials to provide basic photocurrent. The doping of Bi element would adjust the bandgap of SrTiO3, and the organic-inorganic composite material exhibits good photostability and chemical stability that can maintain stable photoelectric properties over a long period of time. Such a novel signal polarity transition strategy greatly broadened the sensor detection to the range of 0.00007-170 ng mL-1 and obtained a relatively low detection limit (25 fg mL-1), which greatly improved the detection sensitivity and accuracy of the biosensor.

Dual-targeted fluorescent probe for tracking polarity and phase transition processes during lipophagy.

Eukaryotic cells regulate various cellular processes through membrane-bound and membrane-less organelles, enabling active signal communication and material exchange. Lysosomes and lipid droplets are representative organelles, contributing to cell lipophagy when their interaction and metabolism are disrupted. Our limited understanding of the interacting behaviours and physicochemical properties of different organelles during lipophagy hinders accurate diagnosis and treatment of related diseases. In this contribution, we report a fluorescent probe, PTZ, engineered for dual-targeting of lipid droplets and lysosomes. PTZ can track liquid-liquid phase separation and respond to polarity shifts through ratiometric fluorescence emission, elucidating the lipophagy process from the perspective of organelle behavior and physicochemical properties. Leveraging on the multifunctionality of PTZ, we have successfully tracked the polarity and dynamic changes of lysosomes and lipid droplets during lipophagy. Furthermore, an unknown homogeneous transition of lipid droplets and lysosomes was discovered, which provided a new perspective for understanding lipophagy processes. And this work is expected to serve as a reference for diagnosis and treatment of lipophagy-related diseases.

Exploring the Subjectivity of English Academic Discourse in the Context of Big Data

Abstract This study develops a sentiment analysis model for English academic discourse based on word information to effectively understand and analyze the sentiment tendencies in English literary texts. The structure of the model includes word embedding layer, character-level feature extraction, word-level feature extraction and feature fusion and classification layer. The word embedding layer realizes the mapping between word vectors and word vectors by microblogging pre-trained word vectors. The character-level feature extraction session uses a multi-window convolutional layer to capture N-Gram information. In contrast, the word-level feature extraction obtains deeper semantic information through a Bi-LSTM layer and fuses it with character-level information to enhance robustness. The feature fusion and classification layer further combines these features and determines the fusion weights through a linear layer to achieve sentiment classification. In performance tests, the model achieves 92.5% sentiment classification accuracy on the standard dataset, an improvement of about 6% compared to traditional methods. In particular, the accuracy is improved by 5% when dealing with text with sentiment polarity transition, showing good adaptability. In addition, using 657 positive and 679 negative sentiment words as seed words effectively expands the sentiment lexicon and enhances the comprehensiveness and accuracy of sentiment analysis.

Paleomagnetic and Rock Magnetic Study of the Gulerghat Area Amravati, Maharashtra

Magnetic Polarity and Stratigraphicstudies of the Narnala section from Akot and Amravatidistricts area(Lat. 21000'-21015'N; Long. 770–77015'E) are carried out. Total thousandsof oriented samples from fresh basalts were collected at close intervals. Detailed palaeomagnetic investigation where carried on 250 samples collected from 20 lava flows belonging to 17 selected traverses were subjected to progressive thermal demagnetizer at 15 different steps of temperatures from 50˚C to 600˚C. Traverse attaining a total thickness of 800m in the study area. Some rocks may fail to retain the magnetic record due to the modification subsequence to their formations by a number of natural phenomena like geotectonic disturbance, metamorphism and alteration, which can produce various degrees of secondary magnetisation in the rock. The secondary magnetisation acquired by the rock is unstable as compared to naturally remain magnetism which can be removed by cleaning techniques like stepwise Alternating field demagnetisation (AFD) and Thermal demagnetisation (TD). The palaeomagnetic results indicate that the most of the flows showed irregular natural remnant directions while a few specimen even from other flows for which a meaningful NRM could be deciphered also showed inconsistent directions. Only 35% of the samples showing irregular directions initially improved on alternating field and stepwise thermal demagnetization. High degree of alteration of the flows appears to have affected the stability of the palaeomagnetic directions. The mean palaeomagnetic directions indicate the presence of lower transitional directions at the bottom part of the sequence and upper reversed polarity in remaining part of the sequence with a few samples showing scattered behavior. The polarity transition has take place in the study area. Ancient latitude calculated for the study area is 30o S and that of Nagpur is 31o S indicating that India has drifted by 51o due N which is more than 5000 Kms. since the formation of this lavas.

Magnetic polarity & stratigraphy of the Bundelkund area Amravati, Maharashtra

Magnetic Polarity and Stratigraphic studies of the Bundelkund area Amravati districts (Lat. 21000'-21015'N; Long. 770–77015'E) are carried out. Total thousands of oriented samples from fresh basalts were collected at close intervals. Detailed palaeomagnetic investigation where carried on 250 samples collected from 20 lava flows belonging to 03 selected traverses were subjected to progressive thermal demagnetizer at 15 different steps of temperatures from 50˚C to 600˚C. Traverse attaining a total thickness of 800m in the study area. Some rocks may fail to retain the magnetic record due to the modification subsequence to their formations by a number of natural phenomena like geotectonic disturbance, metamorphism and alteration, which can produce various degrees of secondary magnetisation in the rock. The secondary magnetisation acquired by the rock is unstable as compared to naturally remain magnetism which can be removed by cleaning techniques like stepwise Alternating field demagnetisation (AFD) and Thermal demagnetisation (TD). The palaeomagnetic results indicate that the most of the flows showed irregular natural remnant directions while a few specimen even from other flows for which a meaningful NRM could be deciphered also showed inconsistent directions. Only 35% of the samples showing irregular directions initially improved on alternating field and stepwise thermal demagnetization. High degree of alteration of the flows appears to have affected the stability of the palaeomagnetic directions. The mean palaeomagnetic directions indicate the presence of lower transitional directions at the bottom part of the sequence and upper reversed polarity in remaining part of the sequence with a few samples showing scattered behavior. The polarity transition has take place in the study area. Ancient latitude calculated for the study area is 30o S and that of Nagpur is 31o S indicating that India has drifted by 51o due N which is more than 5000 Kms. since the formation of this lavas.

PATHOLOGICAL SIGNIFICANCE OF CDH1/E-CADHERIN GERMLINE SEQUENCE VARIANTS IN BREAST CANCER PATIENTS.

Germline alterations of the CDH1 (E-cadherin) tumor suppressor gene have been reported in several epithelial malignancies like hereditary diffuse gastric cancer and lobular breast cancer. E-cadherin plays a central role in proliferation, maintenance of cell-to-cell adhesion, polarity, and epithelial-mesenchymal transition of tissue cells. It is necessary to analyze the impact of the CDH1 germline sequence variants on protein and predict its clinical significance in breast cancer (BC) progression. The aim of the current study was to evaluate the impact and association of CDH1 gene potentially pathogenic variants/likely pathogenic variants (PVs/LPVs) with the initiation and progression of BC. In this study, the clinical data of 200 BC patients have been analyzed based on the type of BC, age, grade, stage, hormonal status, and risk factors. Blood samples from 50 healthy donors were used as a control. Furthermore, CDH1 gene molecular analysis, along with in silico analysis, was provided to assess the invasiveness and progression of BC caused by the E-cadherin protein. Four variants were identified by genetic screening within the CDH1 gene that included variations in exons 7, 8, 10, 11, and 13. Exon 10 had splice site mutation at position c.1337C>A, affecting the protein structure. In exon 11, there was an insertion of T base at position 1669, resulting in truncated protein compared to a normal one that can lead to the disease-causing non- sense-mediated decay and exon 13 variant c.2076T>C has already known polymorphism. In silico analysis of CDH1 showed the presence of the different variants that indicated the overall disruption of protein structure and function. The further functional analysis of these variants and their association with BC can be ensured by increasing the sample size and in vivo studies using mouse models.

Connecting neurodevelopment to neurodegeneration: a spotlight on the role of kinesin superfamily protein 2A (KIF2A).

Microtubules play a central role in cytoskeletal changes during neuronal development and maintenance. Microtubule dynamics is essential to polarity and shape transitions underlying neural cell division, differentiation, motility, and maturation. Kinesin superfamily protein 2A is a member of human kinesin 13 gene family of proteins that depolymerize and destabilize microtubules. In dividing cells, kinesin superfamily protein 2A is involved in mitotic progression, spindle assembly, and chromosome segregation. In postmitotic neurons, it is required for axon/dendrite specification and extension, neuronal migration, connectivity, and survival. Humans with kinesin superfamily protein 2A mutations suffer from a variety of malformations of cortical development, epilepsy, autism spectrum disorder, and neurodegeneration. In this review, we discuss how kinesin superfamily protein 2A regulates neuronal development and function, and how its deregulation causes neurodevelopmental and neurological disorders.

Control of Carrier Polarity and Schottky Barriers in Layered PdSe2 Field-Effect Transistors

Palladium diselenide (PdSe2) has been discovered as an intriguing two-dimensional (2D) semiconductor for its unique pentagonal crystalline structure, electrical and optical anisotropy, thickness-modulated band gap, robust air stability, and high carrier mobility, demonstrating great potential in field-effect transistors (FETs), photodetectors, and thermoelectric devices. Controlling the carrier polarity and electrical contact Schottky barriers is of great significance for realizing high-performance PdSe2 optoelectronic devices. Here, by combining work-function measurement and electrical transport, we observe a thickness-modulated carrier polarity transition in layered PdSe2 FETs from n-type unipolar to intrinsic ambipolar and p-type unipolar behavior by simply varying the number of layers of PdSe2. Due to the weak Fermi-level pinning in few-layer PdSe2, n-type and ambipolar FETs are achieved by contacting PdSe2 to Sc, Ti, and Pd electrodes, respectively. The Schottky barrier heights are determined by temperature-dependent transport, showing a 15 meV barrier for the Sc contact at the electron side and 62 and 93 meV barriers for Ti and Pd contacts, both at the hole side, respectively. We further demonstrate ozone-treatment-induced hole doping in PdSe2, which effectively converts the PdSe2 FETs from n-type to p-type. The doping is robust in the ambient environment over 3 months. In-plane homojunction on a PdSe2 flake is realized by selective ozone doping, demonstrating typical diode rectifying behavior. The ability to control the carrier polarity and Schottky barriers in layered PdSe2 makes this 2D semiconductor highly feasible for complementary metal-oxide semiconductor device integration and high-performance photodetectors based on atomically thin p–n junctions.

Paleomagnetism of the Ediacaran Avellaneda Formation (Argentina), Part II: Magnetic and chemical stratigraphy constraints on the onset of the Shuram carbon excursion

Magnetostratigraphy is a powerful technique for high-resolution stratigraphic correlation and accurate dating of the polarity history of the magnetic field. Up to now, magnetostratigraphic studies have been underutilized in Ediacaran successions. Here, we present a magnetostratigraphy coupled with a carbon isotope study in Ediacaran Avellaneda Formation (∼570 Ma), a sedimentary cover sequence in the Tandilia orogenic belt, of the Río de la Plata craton. Paleomagnetic results and δ13C profiles were obtained from three drill cores that cut across the sedimentary record of the Avellaneda Formation. Paleomagnetic results plotted stratigraphically allowed the identification of a prevalent reverse polarity separated by normal polarity interval. Our findings show a coincident correlative polarity transition at each drill core analyzed. δ13C values demonstrate that the magnetostratigraphic polarity pattern is laterally consistent. Furthermore, C-isotope curves show a transition from positive to negative values near the top of the Avellaneda Formation. This excursion is likely correlative with the onset of the Shuram excursion (ca. 570 Ma). Our findings suggest that the onset of Shuram excursion took place during a reverse polarity chron. Comparison with other coeval sequences validate this correlation. Geomagnetic polarity reversals pattern in the Avellaneda Formation and its correlative pattern, validates a magnetostratigraphy as a potential method to correlate Precambrian strata. Our new findings shed further light on the possible use of magnetic polarity reversals to correlate Ediacaran successions.

Influence of the oceanic crust structure on marine magnetic anomalies: Review and forward modelling

Marine magnetic anomaly strips are important for plate tectonic studies, thereby promoting the development of the geoscience revolution. Most previous studies typically consider a lava layer with vertical polarity boundaries as a simplified magnetic source layer. However, it cannot accurately explain the observed magnetic anomaly data; thus, complex oceanic crusts with multiple magnetic source layers, such as lava, dike, and gabbro layers, and various polarity boundary dip angles should be considered. To date, there is a lack of systematic understanding about how the dike and gabbro layers affect the total marine magnetic anomalies, particularly the effect of lava layers with different boundary inclinations on the intensity and polarity boundary of the magnetic anomaly. This study aimed to confirm the significance of these factors. Hence, we systematically simulated and analysed the magnetic anomaly characteristics with different inclination and magnetization settings for each layer using the forward modelling method and determined the impact of the complexity of the magnetic structure of the oceanic crust on the magnetic anomaly. Our results showed that the contributions of the dike and gabbro layers to the magnetic anomalies was up to 10%–30% and cannot be ignored. Moreover, the polarity transition point may shift with the inclination of the lava, dike, and gabbro layers but is insensitive to the magnetization of each layer. This study emphasizes the significance of the dike and gabbro layers and the inclination variations of different layers, which should be thoroughly studied. This study facilitates a reasonable interpretation of the magnetic structure of the oceanic crust and further refines the boundary of the magnetization zone with alternative polarity.