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Reliable cell type annotations are crucial for investigating cellular heterogeneity in single-cell omics data. Although various computational approaches have been proposed for single-cell RNA sequencing (scRNA-seq) annotation, high-quality cell labels are still lacking in single-cell sequencing assay for transposase-accessible chromatin (scATAC-seq) data, because of extreme sparsity and inconsistent chromatin accessibility between datasets. Here, we present a novel automated cell annotation method that transfers cell type information from a well-labeled scRNA-seq reference to an unlabeled scATAC-seq target, via a parallel graph neural network, in a semi-supervised manner. Unlike existing methods that utilize only gene expression or gene activity features, HyGAnno leverages genome-wide accessibility peak features to facilitate the training process. In addition, HyGAnno reconstructs a reference–target cell graph to detect cells with low prediction reliability, according to their specific graph connectivity patterns. HyGAnno was assessed across various datasets, showcasing its strengths in precise cell annotation, generating interpretable cell embeddings, robustness to noisy reference data and adaptability to tumor tissues. [ABSTRACT FROM AUTHOR]

The performance of advanced materials for extreme environments is underpinned by their microstructure, such as the size and distribution of nano- to micro-sized reinforcing phase(s). Chromium-based superalloys are a recently proposed alternative to conventional face-centred-cubic superalloys for high-temperature applications, e.g., Concentrated Solar Power. Their development requires the determination of precipitate volume fraction and size distribution using Electron Microscopy (EM), as these properties are crucial for the thermal stability and mechanical properties of chromium superalloys. Traditional approaches to EM image processing utilise filtering with a fixed contrast threshold, leads to weak robustness to background noise and poor generalisability to different materials. It also requires an enormous amount of time for manual object measurements on large datasets. Efficient and accurate object detection and segmentation are therefore highly desired to accelerate the development of novel materials like chromium-based superalloys. To address these bottlenecks, based on YOLOv5 and SegFormer structures, this study proposes an end-to-end, two-stage deep learning scheme, DT-SegNet, to perform object detection and segmentation for EM images. The proposed approach can thus benefit from the training efficiency of CNNs at the detection stage (i.e., a small number of training images required) and the accuracy of the ViT at the segmentation stage. Extensive numerical experiments demonstrate that the proposed DT-SegNet significantly outperforms the state-of-the-art segmentation tools offered by Weka and ilastik regarding a large number of metrics, including accuracy, precision, recall and F1-score. This model forms a useful tool to aid alloy development microstructure examinations, and offers significant advantages to address the large datasets associated with high-throughput alloy development approaches. [ABSTRACT FROM AUTHOR]

Objective: It is clinically important for pedicle screws to be placed quickly and accurately. Misplacement of pedicle screws results in various complications. However, the incidence of complications varies greatly due to the different professional titles of physicians and surgical experience. Therefore, physicians must minimize pedicle screw dislocation. This study aims to compare the three nail placement methods in this study, and explore which method is the best for determining the anatomical landmarks and vertical trajectories. Methods: This study involved 70 patients with moderate idiopathic scoliosis who had undergone deformity correction surgery between 2018 and 2021. Two spine surgeons used three techniques (preoperative computed tomography scan [CTS], visual inspection‐X‐freehand [XFH], and intraoperative detection [ID] of anatomical landmarks) to locate pedicle screws. The techniques used include visual inspection for 287 screws in 21 patients, preoperative planning for 346 screws in 26 patients, and intraoperative probing for 309 screws in 23 patients. Observers assessed screw conditions based on intraoperative CT scans (Grade A, B, C, D). Results: There were no significant differences between the three groups in terms of age, sex, and degree of deformity. We found that 68.64% of screws in the XFH group, 67.63% in the CTS group, and 77.99% in the ID group were placed within the pedicle margins (grade A). On the other hand, 6.27% of screws in the XFH group, 4.33% in the CTS group, and 6.15% in the ID group were considered misplaced (grades C and D). The results show that the total amount of upper thoracic pedicle screws was fewer, meanwhile their placement accuracy was lower. The three methods used in this study had similar accuracy in intermediate physicians (P > 0.05). Compared with intermediate physicians, the placement accuracy of three techniques in senior physicians was higher. The intraoperative detection group was better than the other two groups in the good rate and accuracy of nail placement (P < 0.05). Conclusion: Intraoperative common anatomical landmarks and vertical trajectories were beneficial to patients with moderate idiopathic scoliosis undergoing surgery. It is an optimal method for clinical application. [ABSTRACT FROM AUTHOR]

The aim of this study was to synthesize and characterize a novel NO donor, PEI-PO-NONOate, using propylene oxide and to investigate its biosafety and therapeutic efficacy via nasal administration in vitro and vivo. The PEI-PO-NONOate was synthesized based on polyethylenimine (PEI) with different molecular weights and characterized using Fourier transform infrared (FTIR), nuclear magnetic resonance (NMR), and ultraviolet (UV) spectroscopy. Cytotoxicity assays were performed on mouse fibroblast cells L929 and human nasal mucosa epithelial cells (HNEpC), and a rat middle cerebral artery occlusion (MCAO) model was established to evaluate the therapeutic efficacy of PEI-PO-NONOate via nasal administration. The PEI-PO-NONOate was found to be stable under dark, dry, and airproof conditions, and its release was accelerated in an aqueous phase or acidic environment, while it was slowed down in a polyethylene glycol (PEG) mixture system. The NO donor released approximately 0.4, 0.5, and 0.6 μmol of gaseous NO from 1.0 mg of the polymer based on PEI600, PEI1800, and PEI10K, respectively. Cytotoxicity assays showed that the PEI-PO-NONOates had a cryoprotective effect as compared with PEI and PEI-PO. Furthermore, nasal administration of PEI-PO-NONOates resulted in a significant reduction in overall necrotic ratio as compared with the control group (16.4% versus 24.6%, p < 0.05). The findings of this study suggest that PEI-PO-NONOates may have potential as an adjuvant therapy for acute ischemic stroke when administered via the nasal route. • Similar NO donor was synthesized using PEI of wide-range molecular weight via previously reported approach, and comprehensive characterizations were performed. • Biosafety was evaluated using human nasal mucosa epithelial cells (HNEpC) and mouse fibroblast cells (L929). • Rat middle cerebral artery occlusion (MCAO) was established as animal model of acute ischemic stroke, and the therapeutic efficacy of the obtained NO donor via nasal administration was determined. [ABSTRACT FROM AUTHOR]

In this Letter, we demonstrated deep sub-60 mV/dec subthreshold swings (SS) independent of gate bias sweep direction in GaN-based metal–insulator–semiconductor high electron mobility transistors (MISHEMTs) with an Al0.6Ga0.4N/GaN heterostructure and in situ SiN as gate dielectric and surface passivation. Average SS values of 22 and 29 mV/dec over 3–4 orders of drain current (ID) swing were measured during forward and reverse sweeps, respectively, in a 75-nm gate length (LG) device. Sub-60 mV/dec SS was also observed in the GaN MISHEMTs with longer LG up to 350 nm. The intrinsic physical mechanisms of deep sub-60 mV/dec SS were comprehensively studied. The observed negative differential resistance in the gate current, the kinks in the output ID-VD curve, and the capacitance spike in the depletion region of the C–V curves suggest that the capture and emission of electrons in the traps are the dominant physical mechanisms responsible for the small SS. [ABSTRACT FROM AUTHOR]

Knowledge Graphs (KGs), a structural way to model human knowledge, have been a critical component of many artificial intelligence applications. Many KG-based tasks are built using knowledge representation learning, which embeds KG entities and relations into a low-dimensional semantic space. However, the quality of representation learning is often limited by the heterogeneity and sparsity of real-world KGs. Multi-KG representation learning, which utilizes KGs from different sources collaboratively, presents one promising solution. In this paper, we propose a simple, but effective iterative method that post-processes pre-trained knowledge graph embedding (IPPT4KRL) on individual KGs to maximize the knowledge transfer from another KG when a small portion of alignment information is introduced. Specifically, additional triples are iteratively included in the post-processing based on their adjacencies to the cross-KG alignments to refine the pre-trained embedding space of individual KGs. We also provide the benchmarking results of existing multi-KG representation learning methods on several generated and well-known datasets. The empirical results of the link prediction task on these datasets show that the proposed IPPT4KRL method achieved comparable and even superior results when compared against more complex methods in multi-KG representation learning. [ABSTRACT FROM AUTHOR]

To promote the resilient and coordinated development of regional economies, in this study, to construct an index system, we used the entropy weight method to measure the agricultural economic resilience of 11 prefecture-level cities in Jiangxi province, China during 2011–2020, and we analyzed the characteristics of their spatial-temporal pattern evolution. We used the Theil index method to analyze the main sources of their spatial differences. The results showed that: First, the mean value of agricultural economic resilience of prefecture-level cities in Jiangxi trended upward during 2011–2020. Among the prefecture-level cities, Ganzhou had the highest mean agricultural economic resilience value, while Yingtan had the lowest. From the perspective of regional division, the agricultural economy in southern Jiangxi was the most resilient, whereas that in northeast Jiangxi was the least. Second, since 2011, the overall difference in agricultural economic resilience in the four regions of Jiangxi has trended downward, with the inter-regional difference being the main source of the overall difference. Based on this, we provide the following policy implications: first, to continuously enhance the intrinsic dynamics of the agricultural economic resilience and strengthen policy support in Jiangxi; second, to coordinate the development of regional agricultural economic resilience and achieve overall improvement. [ABSTRACT FROM AUTHOR]

A low ohmic contact resistance (Rc) is a challenge for an AlGaN/GaN heterostructure with a high Al-composition barrier, which is highly desired to further push the performance of GaN transistors. In this Letter, an effective ohmic contact technique with an in situ SiNx layer inserted between the conventional Ti/Al/Ni/Au metal stack and the III-nitride was proposed and the inside physical mechanisms were investigated for an Al0.65Ga0.35N/GaN heterostructure. The fabricated ohmic contact has a low Rc of 0.17 Ω·mm and a specific contact resistivity value (ρc) of 8.45 × 10−7 Ω·cm2, which is obviously improved compared with the Rc of 0.32 Ω·mm and ρc of 2.84 × 10−6 Ω·cm2 without in situ SiNx inserted. The strong temperature dependency of ρc with in situ SiNx insertion shows that the dominant current transport mechanism is the thermionic field emission. Transmission electron microscopy and energy dispersive x-ray spectroscopy analyses suggest that the enhanced ohmic contact is due to the possible formation of low-work function silicides and more TiN alloys during annealing. [ABSTRACT FROM AUTHOR]

In this Letter, a mechanism of current-collapse free for high-performance lateral AlGaN/GaN Schottky barrier diodes (SBDs) with a thick single-crystal GaN cap layer is investigated. A high breakdown voltage of 1.74 kV and a low specific on-resistance (RON,sp) of 5.04 mΩ cm2 are achieved for the fabricated SBD with a spatial distance (LAC) of 15 μm. Benefiting from the optimized groove anode technique, including a low-damaged etching process and a post-anode-annealing process, a low leakage current of 87 nA/mm at −500 V as well as a low turn-on voltage of 0.8 V defined at an anode current density of 1 mA/mm are obtained. Holes induced by polarization effects at the GaN/AlGaN interface inject to the anode edge at the ON state, and the negatively charged centers induced by a groove etching process are neutralized, which lead to the suppressed tunneling current (ITU) and idealized ideality factor (η). The forward current density decreases due to the suppressed ITU at the barrier-limited region. When the devices are biased at the OFF state, holes around cathodes inject to the buffer layer, which suppress hole emission at the buffer layer, and current collapse is greatly suppressed even after a 300-s-long bias test at −600 V. [ABSTRACT FROM AUTHOR]

In this letter, we report on demonstrating high-performance enhancement-mode (E-mode) ${p}$ -channel GaN Fin Field-Effect Transistors (FinFETs) fabricated on a proposed ${p}$ -GaN/AlN/AlGaN epitaxial structure with a low sheet resistance of 14 $\text{k}\Omega / {\unicode{0x25A1}} $. Benefiting from the 25-nm-wide GaN nanowires channel and tri-gate architecture, high threshold voltage (${V}_{\text{TH}}$) of −2.2 V and low subthreshold swing (SS) of 130 mV/dec were obtained. Meanwhile, owing to the removal of etching damage in the recessed region and the post gate annealing, high drain current density of 18.5 mA/mm and high ${I}_{ \mathrm{\scriptscriptstyle ON}} / I_{ \mathrm{\scriptscriptstyle OFF}}$ ratio of $3\times10$ 8 were acquired. The E-mode ${p}$ -channel GaN FinFET fabricated on the reformative epitaxial structure with lower sheet resistance shows the potential to be one step closer to realizing the vision of GaN CMOS technology. [ABSTRACT FROM AUTHOR]

In this article, the single event burnout (SEB) performances for 2DEG Alx $\text{Ga}_{{1}-{x}}\text{N}$ channel p-GaN gate high electron mobility transistors (HEMTs) have been investigated comprehensively to reveal the failure mechanisms and broaden applications in harsh environments. As Al composition ${x}$ increases from 0.0 to 0.4, ${V}_{\text {BR}}$ increases from 500 to 730 V, and the corresponding SEB voltage ${V}_{\text {SEB}}$ at linear energy transfer (LET) = 10 pC/ $\mu \text{m}$ increases from 300 to 450 V. Possible mechanisms of Alx $\text{Ga}_{{1}-{x}}\text{N}$ channel HEMTs from the perspective of electric field (${E}$ -field) are proposed. ${E}$ -field near source and drain side after radiation would have a high peak ${E}$ -field and that of p-GaN layer exceeds 3.3 MV/cm of critical ${E}$ -field for GaN material, causing SEB to occur (LET = 10 pC/ $\mu \text{m}$). When SEB occurs in HEMTs, ${E}$ -field would increase rapidly and cannot be recovered. A new phenomenon has been first discovered when SEB occurs in Alx $\text{Ga}_{{1}-{x}}\text{N}$ channel HEMTs with p-GaN gate (${x} = {0.0}$ –0.4, step = 0.1). In addition to the back-channel effect, an excess of holes would be left in the buffer layer after electrons flow toward the drain. It allows the injection of an excess of holes in the buffer layer into the gate with low potential, resulting in a sharp increase in ${I}_{\text {G}}$. Simulation results indicate that AlGaN channel HEMTs have great advantages in SEB performances compared with the traditional GaN channel HEMTs. [ABSTRACT FROM AUTHOR]

In this article, we report on demonstrating high-performance AlGaN/GaN high-electron-mobility-transistor (HEMT) on free-standing GaN (FS-GaN) substrate with low contact resistance (${R}_{C}$) and high breakdown voltage (BV). Non-regrowth ${R}_{C}$ as low as $0.23 \Omega \cdot $ mm was achieved by using the self-aligned Ohmic etching process and nonfield plated BV as high as 193 V was also acquired due to the low dislocation density of the epi-layer on FS-GaN substrate. It is found that the reduction of the ${R}_{C}$ is induced by the smaller electron tunneling width across the AlGaN barrier layer, rather than the formation of dislocation related metal spikes. The fabricated GaN HEMT was a peak extrinsic transconductance (${g}_{m}$) of 203 mS/mm and a drain current (${I}_{D}$) ON/OFF ratio of 106–107. Benefited from the low ${R}_{C}$ , a cut-off frequency/maximum oscillation frequency (${f}_{T}/{f}_{max}$) of 26/73 GHz was extracted at a gate length (${L}_{g}$) of 600 nm, yielding a ${f}_{T}\cdot {L}_{g}$ value of 15.6 GHz $\cdot \mu \text{m}$ and a Johnson’s figure-of-merit (J-FOM) of 5.0 THz $\cdot \text{V}$ , which are the highest values among all AlGaN/GaN HEMTs on FS-GaN substrate. This work implies that GaN HEMTs on FS-GaN substrate with low ${R}_{C}$ turn out to be a promising candidate for high-performance radio frequency (RF) power device applications. [ABSTRACT FROM AUTHOR]