Monolithic three-dimensional tier-by-tier integration via van der Waals lamination.

Two-dimensional (2D) semiconductors have shown great potential for monolithic three-dimensional (M3D) integration due to their dangling-bonds-free surface and the ability to integrate to various substrates without the conventional constraint of lattice matching1-10. However, with atomically thin body thickness, 2D semiconductors are not compatible with various high-energy processes in microelectronics11-13, where the M3D integration of multiple 2D circuit tiers is challenging. Here we report an alternative low-temperature M3D integration approach by van der Waals (vdW) lamination of entire prefabricated circuit tiers, where the processing temperature is controlled to 120 °C. By further repeating the vdW lamination process tier by tier, an M3D integrated system is achieved with 10 circuit tiers in the vertical direction, overcoming previous thermal budget limitations. Detailed electrical characterization demonstrates the bottom 2D transistor is not impacted after repetitively laminating vdW circuit tiers on top. Furthermore, by vertically connecting devices within different tiers through vdW inter-tier vias, various logic and heterogeneous structures are realized with desired system functions. Our demonstration provides a low-temperature route towards fabricating M3D circuits with increased numbers of tiers.

Highly Robust Room-Temperature Interfacial Ferromagnetism in Ultrathin Co2Si Nanoplates.

The reduced dimensionality and interfacial effects in magnetic nanostructures open the feasibility to tailor magnetic ordering. Here, we report the synthesis of ultrathin metallic Co2Si nanoplates with a total thickness that is tunable to 2.2 nm. The interfacial magnetism coupled with the highly anisotropic nanoplate geometry leads to strong perpendicular magnetic anisotropy and robust hard ferromagnetism at room temperature, with a Curie temperature (TC) exceeding 950 K and a coercive field (HC) > 4.0 T at 3 K and 8750 Oe at 300 K. Theoretical calculations suggest that ferromagnetism originates from symmetry breaking and undercoordinated Co atoms at the Co2Si and SiO2 interface. With protection by the self-limiting intrinsic oxide, the interfacial ferromagnetism of the Co2Si nanoplates exhibits excellent environmental stability. The controllable growth of ambient stable Co2Si nanoplates as 2D hard ferromagnets could open exciting opportunities for fundamental studies and applications in Si-based spintronic devices.

Two-Dimensional Ultrathin Fe3Sn2 Kagome Metal with Defect-Dependent Magnetic Property.

Two-dimensional (2D) Fe3Sn2, which is a room-temperature ferromagnetic kagome metal, has potential applications in spintronic devices. However, the systematic synthesis and magnetic study of 2D Fe3Sn2 single crystals have rarely been reported. Here we have synthesized 2D hexagonal and triangular Fe3Sn2 nanosheets by controlling the amount of FeCl2 precursors in the chemical vapor deposition (CVD) method. It is found that the hexagonal Fe3Sn2 nanosheets exist with Fe vacancy defects and show no obvious coercivity. While the triangular Fe3Sn2 nanosheet has obvious hysteresis loops at room temperature, its coercivity first increases and then remains stable with an increase in temperature, which should result from the competition of the thermal activation mechanism and spin direction rotation mechanism. A first-principles calculation study shows that the Fe vacancy defects in Fe3Sn2 can increase the distances between Fe atoms and weaken the ferromagnetism of Fe3Sn2. The resulting 2D Fe3Sn2 nanosheets provide a new choice for spintronic devices.

A Novel Low-Density-Biomass-Carbon Composite Coated with Carpet-like and Dandelion-Shaped Rare-Earth-Doped Cobalt Ferrite for Enhanced Microwave Absorption.

A novel low-density composite for the absorption of microwaves was prepared by loading La-doped spinel cobalt ferrite (La-CFO) onto biomass carbon (BC) derived from corn stalks using a hydrothermal method. This composite (La-CFO@BC) not only maintained the advantageous properties of low density and abundant porosity, but also exhibited a unique morphology, with La-CFO displaying a carpet-like structure interspersed with dandelion-shaped particles. The incorporation of La-CFO effectively tuned the electromagnetic parameters of the composite, thereby improving its impedance-matching attributes and its ability to absorb microwave radiation. At a frequency of 12.8 GHz for electromagnetic waves and with a thickness of 2.5 mm, La-CFO@BC demonstrated remarkable performance in microwave absorption, attaining a noteworthy minimum reflection (RLmin) of -53.2 dB and an effective absorption bandwidth (EAB) of 6.4 GHz. Furthermore, by varying the thickness of the La-CFO@BC within the range of 1.0 to 5.5 mm, the EAB could be broadened to 13.8 GHz, covering the entire X-band, the entire Ku-band, and a substantial portion of the C-band. This study demonstrated that La-CFO@BC was a promising alternative for electromagnetic wave attenuation, which offered superior performance in microwave absorption.

GELT: A graph embeddings based lite-transformer for knowledge tracing.

The development of intelligent education has led to the emergence of knowledge tracing as a fundamental task in the learning process. Traditionally, the knowledge state of each student has been determined by assessing their performance in previous learning activities. In recent years, Deep Learning approaches have shown promising results in capturing complex representations of human learning activities. However, the interpretability of these models is often compromised due to the end-to-end training strategy they employ. To address this challenge, we draw inspiration from advancements in graph neural networks and propose a novel model called GELT (Graph Embeddings based Lite-Transformer). The purpose of this model is to uncover and understand the relationships between skills and questions. Additionally, we introduce an energy-saving attention mechanism for predicting knowledge states that is both simple and effective. This approach maintains high prediction accuracy while significantly reducing computational costs compared to conventional attention mechanisms. Extensive experimental results demonstrate the superior performance of our proposed model compared to other state-of-the-art baselines on three publicly available real-world datasets for knowledge tracking.

Study on the anti-mitochondrial apoptosis mechanism of Erigeron breviscapus injection based on UPLC-Q-TOF-MS metabolomics and molecular docking in rats with cerebral ischemia-reperfusion injury.

ETHNOPHARMACOLOGICAL RELEVANCE: Erigeron breviscapus is a common medicine of eight ethnic minorities, including Miao, Naxi, and Yi. As early as the Ming Dynasty (AD 1368-1644), Lanmao's Materia Medica of Southern Yunnan (AD 1436) recorded that the medicine is used for the treatment of "Zuo tan you huan." In modern pharmacological research, Erigeron breviscapus injection is the most commonly used preparation in the treatment of ischemic stroke caused by acute cerebral infarction, but its mechanism of action in the treatment of ischemic stroke is not well understood. AIM OF THE STUDY: In this study, a metabonomics study based on ultraperformance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (UPLC-QTOF-MS) was used in investigating the effect of a traditional Chinese medicine preparation Erigeron breviscapus injection on the rat model of focal cerebral ischemia-reperfusion and the affinity of its main components with the targets of mitochondrial apoptotic pathways. MATERIALS AND METHODS: This study used molecular docking technology to verify the effective binding ability of main effective components of Erigeron breviscapus injection to target proteins related to mitochondrial apoptosis pathway. This study developed a metabonomics method based on the ultra-performance liquid chromatography combined with quadrupole time-of-flight tandem mass spectrometry (UPLC Q-TOF MS) to evaluate the efficacy and study the mechanism of traditional Chinese medicine preparation. With pattern recognition analysis (principal component analysis and partial least squares-discriminate analysis) of urinary metabolites, a clear separation of focal cerebral ischemia-reperfusion model group and healthy control group was achieved. RESULTS: Erigeron breviscapus injection can significantly reduce the area of cerebral infarction, improve tissue morphological lesion in rats, and can increase the number of Nissl bodies. It may be a promoting factor by inhibiting hippocampal nerve cell apoptosis and Bax protein expression and by exerting effects against ischemia reperfusion after the induction of apoptosis. Thus, it plays a role in brain protection. Moreover, it can considerably promote the recovery of neurological deficiency signs in advance. Meanwhile, Erigeron breviscapus decreased malondialdehyde content and T-NOS activity. Its curative effect from strong to weak order: low dose > high dose > medium dose. The representative components of Erigeron breviscapus have good affinity with the active sites of mitochondrial apoptosis-related proteins. Metabolomics found that the potential biomarkers regulated by breviscapine are kynurequinolinic acid, succinylornithine, and leucine proline. It is speculated that it may participate in TRP-kynurequinolinic acid and succinylornithine-urea cycle-NO metabolic pathways. CONCLUSIONS: This paper revealed the potential biomarkers and metabolic pathways regulated by Erigeron breviscapus. It was speculated that the mechanism is related to its inhibition of mitochondrion-mediated apoptosis. Erigeron breviscapus could restore the metabolic profiles of the model animals to normal animal levels. The mechanism may be related to the potential biomarkers of quinolinic acid, succinylornithine, and leucine proline and the metabolic pathways involved. However, the exact mechanism by which Erigeron breviscapus inhibits mitochondrion-mediated apoptosis remains to be further explored.

LC-MS based metabonomics study on protective mechanism of ESWW in cerebral ischemia via CYTC/Apaf-1/NDRG4 pathway.

BACKGROUND: Ershiwuwei Zhenzhu pills was originally recorded in the Tibetan medical book Si Bu Yi Dian in the 8th century AD and is now included in the Pharmacopoeia of the People's Republic of China (2020). The pills can calm the nerves and open the mind as well as treat cerebral ischemia reperfusion injury, stroke, hemiplegia. However, its quality standards have not yet been established, and the therapeutic effect on cerebral ischemia by regulating the mitochondrial apoptosis pathway has not been elucidated. STUDY DESIGN AND METHODS: LC-MS was used to establish quality standards for Ershiwuwei Zhenzhu pills. Metabonomics, molecular docking, neuroethology, cerebral infarction ratio, pathological detection of diencephalon, cortex, and hippocampus, and molecular biology techniques were used to reveal the mechanism of the pills in regulating the mitochondrial apoptosis pathway to treat cerebral ischemia. RESULTS: The contents of 20 chemical components in Ershiwuwei Zhenzhu pills from 12 batches and 8 manufacturers was determined for the first time. Eleven differential metabolites and three metabolic pathways, namely, fructose and mannose metabolism, glycerophospholipid metabolism, and purine metabolism, were identified by metabonomics. The pills improved the neuroethology abnormalities of MCAO rats and the pathological damage in the diencephalon and decreased the ratio of cerebral infarction. It also significantly reduced the mRNA expression of AIF, Apaf-1, cleared caspase8, CytC, and P53 mRNA in the brain tissue and the protein expression of Apaf-1 and CYTC and increased the protein expression of NDRG4. CONCLUSION: In vitro quantitative analysis of the in vitro chemical components of Ershiwuwei Zhenzhu pills has laid the foundation for improving its quality control. The potential mechanism of the pills in treating cerebral ischemia may be related to the Apaf-1/CYTC/NDRG4 apoptosis pathway. This work provides guidance for clinical drug use for patients.

High-density vertical sidewall MoS2 transistors through T-shape vertical lamination.

Vertical transistors, in which the source and drain are aligned vertically and the current flow is normal to the wafer surface, have attracted considerable attention recently. However, the realization of high-density vertical transistors is challenging, and could be largely attributed to the incompatibility between vertical structures and conventional lateral fabrication processes. Here we report a T-shape lamination approach for realizing high-density vertical sidewall transistors, where lateral transistors could be pre-fabricated on planar substrates first and then laminated onto vertical substrates using T-shape stamps, hence overcoming the incompatibility between planar processes and vertical structures. Based on this technique, we vertically stacked 60 MoS2 transistors within a small vertical footprint, corresponding to a device density over 108 cm-2. Furthermore, we demonstrate two approaches for scalable fabrication of vertical sidewall transistor arrays, including simultaneous lamination onto multiple vertical substrates, as well as on the same vertical substrate using multi-cycle layer-by-layer laminations.