Graph Neural Networks (GNNs) have been widely applied to various fields due to their powerful representations of graph-structured data. Despite the success of GNNs, most existing GNNs are designed to ...learn node representations on the fixed and homogeneous graphs. The limitations especially become problematic when learning representations on a misspecified graph or a heterogeneous graph that consists of various types of nodes and edges. To address these limitations, we propose Graph Transformer Networks (GTNs) that are capable of generating new graph structures, which preclude noisy connections and include useful connections (e.g., meta-paths) for tasks, while learning effective node representations on the new graphs in an end-to-end fashion. We further propose enhanced version of GTNs, Fast Graph Transformer Networks (FastGTNs), that improve scalability of graph transformations. Compared to GTNs, FastGTNs are up to 230× and 150× faster in inference and training, and use up to 100× and 148× less memory while allowing the identical graph transformations as GTNs. In addition, we extend graph transformations to the semantic proximity of nodes allowing non-local operations beyond meta-paths. Extensive experiments on both homogeneous graphs and heterogeneous graphs show that GTNs and FastGTNs with non-local operations achieve the state-of-the-art performance for node classification tasks. The code is available: https://github.com/seongjunyun/Graph_Transformer_Networks
Diabetes mellitus (DM) is a serious disease in which blood sugar levels rise abnormally because of failed insulin production or decreased insulin sensitivity. Although many studies are being ...conducted for the treatment or early diagnosis of DM, it is not fully understood how mitochondrial genome (mtDNA) abnormalities appear in patients with DM. Here, we induced iPSCs from fibroblasts, PBMCs, or pancreatic cells of three patients with type 2 DM (T2D) and three patients with non-diabetes counterpart. The mtDNA mutations were detected randomly without any tendency among tissues or patients. In T2D patients, 62% (21/34) of iPSC clones harbored multiple mtDNA mutations, of which 37% were homoplasmy at the 100% mutation level compared to only 8% in non-diabetes. We next selected iPSC clones that were a wild type or carried mutations and differentiated into pancreatic cells. Oxygen consumption rates were significantly lower in cells carrying mutant mtDNA. Additionally, the mutant cells exhibited decreased production of insulin and reduced secretion of insulin in response to glucose. Overall, the results suggest that screening mtDNA mutations in iPSCs from patients with T2D is an essential step before pancreatic cell differentiation for disease modeling or autologous cell therapy. BMB Reports 2022; 55(9): 453-458
Purpose: The aim of this multicenter study was to investigate the malignancy risk of minimally cystic thyroid nodules (MCTNs) using cyto-histopathologic diagnoses as the reference standard.Methods: ...From June 2015 to September 2015, 5,601 thyroid nodules (≥1 cm) from 4,989 consecutive patients who underwent thyroid ultrasonography (US) at 26 institutions were retrospectively analyzed. Each thyroid nodule was categorized according to its cystic proportion: purely solid, minimally cystic (≤10%), and partially cystic (>10%). The malignancy risk of MCTNs was compared with those of purely solid nodules and partially cystic thyroid nodules (PCTNs). The malignancy risk of MCTNs was assessed according to echogenicity and the presence of suspicious US features.Results: The prevalence of MCTNs was 22.5%. The overall malignancy risk of MCTNs was 8.8%, which was significantly lower than that of purely solid nodules (29.5%) (P<0.001), and slightly higher than that of PCTNs (6.2%) (P=0.013). The risk of malignancy associated with MCTNs was similar to that of PCTNs regardless of echogenicity or the presence of suspicious US features (all P>0.05). MCTNs were associated with a higher risk of malignancy in hypoechoic nodules than in isohyperechoic nodules and in nodules with suspicious US features than in those without suspicious US features (all P<0.001).Conclusion: The malignancy risk of MCTNs was significantly lower than that of purely solid nodules. MCTNs could be categorized as PCTNs rather than as solid nodules to increase the accuracy of the risk stratification system for thyroid nodules.
Internal Heavy Atom Effect
In article number 2104646, Jihoon Lee, Min Chul Suh, Seunghyup Yoo, and co‐workers show how incorporating the internal heavy atom (IHA) effect can impact the reverse ...intersystem crossing (RISC) and device performance. The spectroscopic and theoretical results indicate that a fast RISC may not be the sole factor important for reducing efficiency roll‐off and that the spin‐flip cycles considering both T1 → S1 and S1 → T1 should be carefully taken into account to derive a complete picture of the IHA effect on efficiency roll‐off behavior.
Despite the many efforts to solve the problem associated with lithium storage at high rates, it is rarely achieved up until now. The design with experimental proof is reported here for the high rate ...of lithium storage via a core–shell structure composite comprised of a Li4Ti5O12 (LTO) core and a nanographene (NG) shell. The LTO-NG core–shell was synthesized via a first-principles understanding of the adsorption properties between LTO and NG. Interfacial reactions are considered between the two materials by a redox coupling effect. The large interfacial area between the LTO core and the NG shell resulted in a high electron-conducting path. It allowed rapid kinetics to be achieved for lithium storage and also resulted in a stable contact between LTO and NG, affording cyclic performance stability.
Despite extensive research on ultraviolet (UV) sensors based on core–shell heterostructures, most of them exhibit low sensitivities, slow response/recovery times, and unsatisfactory long‐term ...stabilities, thereby limiting their use in real‐time applications. To solve these problems, a highly sensitive and stable surface acoustic wave (SAW) UV sensor based on novel tantalum pentoxide (Ta2O5) coated 1D zinc oxide (ZnO)/tin dioxide (SnO2) core–shell nanostructures is introduced. The fabricated SAW‐based UV sensor system, including sensor interface electronics, exhibits a high UV response, fast response/recovery time, and long‐term stability. Prior to device fabrication, coupling of mode (COM) modeling is performed to calculate the optimal parameters for the SAW device. Photoluminescence and X‐ray photoelectron spectroscopy measurements reveal that the Ta2O5 layer coating effectively suppresses the recombination of photogenerated carriers, leading to an increase in the carrier density and improvement in the UV sensing properties. The evaluated sensitivity and linearity of the proposed sensor are 120.36 ppm (mW cm−2)−1 and 0.988, respectively, in the range of 1–60 µW cm−2. The sensing mechanism of the proposed UV sensor is discussed in detail. Using COMSOL simulations and photo‐corrosion experiments, it is found that the Ta2O5 coated ZnO/SnO2 core–shell heterostructure minimizes the effects of humidity and improves stability.
A highly sensitive and stable surface acoustic wave UV sensor based on Tantalum pentoxide (Ta2O5) coated 1D zinc oxide (ZnO)/tin dioxide (SnO2) nanostructures is introduced. The sensor shows high UV response, fast response/recovery time, and stability. The evaluated sensitivity and linearity are 120.36 ppm (mW cm−2)−1 and 0.988, respectively, in the range of 1–60 µW cm−2.
The development of stretchable energy storage systems for fully power-independent and stretchable devices for the next generation is increasing. Here, we report on a graphene–carbon-nanotube-layered ...structure for use as a stretchable electrode and its application in all-solid-state stretchable supercapacitors and various electronics. In this system, graphene serves as a floating track and carbon nanotubes convert external stress into the stretching motion of the electrode. The structure provides omnidirectional deformation without inhomogeneous interface stress and slip stress between active sites and the stretching passive components. The suggested system offers significant improvement over existing methodologies for fabricating stretchable energy storage systems and electronics in terms of density of capacitance, negligible passive volume, biaxial and twisted deformation, and durability. The integration of stretchable electrodes in various substrates and their application as all-solid-state, stretchable supercapacitors are demonstrated, and a high value of capacitance in the deformed state of 329Fg−1 was achieved (based on mass of the graphene). The physical characteristics of the system are also revealed by first-principle calculations and three-dimensional finite-element methods.
Display omitted
•Omnidirectionally stretchable, all-solid-state supercapacitor is achieved based on graphene–CNT layered structure.•No obvious conductance fading of graphene–CNT electrode is observed after 100 cycles stretching/releasing.•Graphene–CNT stretchable electrode shows excellent supercapacitor characteristics.•Very stable and reversible capacitive properties are noted during stretching/releasing.
PDF
