Two cities, two stages in transforming society-a mixed methods study comparing doctors' adoption of mobile apps for communication with patients in Hangzhou and Yancheng, China.

Objectives: Mobile apps have become commonplace in doctor-patient communication over the last 20 years. Doctors mainly use two kinds of app, social networking apps (i.e., WeChat) and medical platform apps (i.e., Haodf). The purpose of this study was to investigate whether the attributes of social interaction in local society impact doctors' choice of mobile apps to communicate with patients. This article addresses two research questions: (a) To what degree do doctors' adoption patterns in different societies differ? (b) Why do doctors choose certain mobile apps to communicate with patients? Methods: This study employed a mixed methods research design to analyze doctor's adoption behavior patterns in two cities, Hangzhou (HZ) and Yancheng (YC), which represent two stages in transforming society. Various patterns, measured as the percentage of doctors who utilize the medical platform app of Haodf among all doctors and the average service counts per doctor, were compared in three groups of tertiary hospitals: the top ones in HZ, the average ones in HZ, and the average ones in YC. We also conducted thematic content analysis of qualitative data from semi-structured interviews with 20 purposely selected doctors in the two cities. Results: The percentages of doctors who have adopted the app of Haodf from the three groups of tertiary hospitals were 49.97%, 41.00%, and 32.03%, with an average service counts per doctor of 261, 182 and 39, respectively. According to the interviewees, doctors from YC are more likely to use social networking apps to communicate with patients than their HZ counterparts to maintain social connections with their relatives, friends, colleagues, and others. Conclusion: This study demonstrates that doctors' choices of mobile apps are dependent upon social context. In traditional society, where people have close ties, the logic of using social networking apps lies in doctors' need to maximize the utility of their knowledge by maintaining social connections with others. In modern society, where the close ties between people have gradually weakened, the logic of using medical platform apps lies in doctors' needs for reputation marketing, either for themselves or for institutions, their affiliated departments or hospitals.

A multi-resolution TOF-DOI detector for human brain dedicated PET scanner.

Objective. We propose a single-ended readout, multi-resolution detector design that can achieve high spatial, depth-of-interaction (DOI), and time-of-flight (TOF) resolutions, as well as high sensitivity for human brain-dedicated positron emission tomography (PET) scanners.Approach. The detector comprised two layers of LYSO crystal arrays and a lightguide in between. The top (gamma ray entrance) layer consisted of a 16 × 16 array of 1.53 × 1.53 × 6 mm3LYSO crystals for providing high spatial resolution. The bottom layer consisted of an 8 × 8 array of 3.0 × 3.0 × 15 mm3LYSO crystals that were one-to-one coupled to an 8 × 8 multipixel photon counter (MPPC) array for providing high TOF resolution. The 2 mm thick lightguide introduces inter-crystal light sharing that causes variations of the light distribution patterns for high DOI resolution. The detector was read out by a PETsys TOFPET2 application-specific integrated circuit.Main result. The top and bottom layers were distinguished by a convolutional neural network with 97% accuracy. All crystals in the top and bottom layers were resolved. The inter-crystal scatter (ICS) events in the bottom layer were identified, and the measured average DOI resolution of the bottom layer was 4.1 mm. The coincidence time resolution (CTR) for the top-top, top-bottom, and bottom-bottom coincidences was 476 ps, 405 ps, and 298 ps, respectively. When ICS events were excluded from the bottom layer, the CTR of the bottom-bottom coincidence was 277 ps.Significance. The top layer of the proposed two-layer detector achieved a high spatial resolution and the bottom layer achieved a high TOF resolution. Together with its high DOI resolution and detection efficiency, the proposed detector is well suited for next-generation high-performance brain-dedicated PET scanners.

Obstructive sleep apnea affects the psychological and behavioural development of children-a case-control study.

This study aims to investigate the effects of obstructive sleep apnea on paediatric psychological and behavioural abnormalities. A total of 1086 paediatric patients with obstructive sleep apnea and 728 sample snoring controls were enrolled in the study. Patients with obstructive sleep apnea underwent bilateral tonsillectomy plus adenoidectomy or adenoidectomy alone. Repeated Autism Behaviour Checklist, Spence Children's Anxiety Scale, and Children's Depression Inventory were performed to assess the autism symptoms, anxiety level and depressive symptoms before and after surgery. The score of Autism Behaviour Checklist in preschool children with obstructive sleep apnea was higher than that in control. In school children with obstructive sleep apnea, the score of Spence Children's Anxiety Scale was also higher. School children with obstructive sleep apnea with depressive symptoms were significantly higher than that in control. The scores of Autism Behaviour Checklist, Spence Children's Anxiety Scale, and Children's Depression Inventory in the obstructive sleep apnea group after surgery were significantly lower than that before surgery. Our study showed that the score of Spence Children's Anxiety Scale and Children's Depression Inventory had a close correlation with the illness course and hypoxia duration. The Spence Children's Anxiety Scale and Children's Depression Inventory scores are also closely associated with the Autism Behaviour Checklist score. These results suggest that obstructive sleep apnea may have a significant impact on autism symptoms, anxiety levels and depressive symptoms in children. We found that the longer the duration of the obstructive sleep apnea course and hypoxia, the greater the impact on anxiety level and depressive symptoms. The suspected autism symptoms, anxiety level and depressive symptoms in children with obstructive sleep apnea were also significantly correlated. Thus, early detection and timely treatment may often reverse the psychological and behavioural abnormalities caused by obstructive sleep apnea.

Emergent symmetry in quantum phase transition: From deconfined quantum critical point to gapless quantum spin liquid.

The emergence of exotic quantum phenomena in frustrated magnets is rapidly driving the development of quantum many-body physics, raising fundamental questions on the nature of quantum phase transitions. Here we unveil the behaviour of emergent symmetry involving two extraordinarily representative phenomena, i.e., the deconfined quantum critical point (DQCP) and the quantum spin liquid (QSL) state. Via large-scale tensor network simulations, we study a spatially anisotropic spin-1/2 square-lattice frustrated antiferromagnetic (AFM) model, namely the J1x-J1y-J2 model, which contains anisotropic nearest-neighbor couplings J1x,J1y and the next nearest neighbor coupling J2. For small J1y/J1x, by tuning J2, a direct continuous transition between the AFM and valence bond solid phase is observed. With growing J1y/J1x, a gapless QSL phase gradually emerges between the AFM and VBS phases. We observe an emergent O(4) symmetry along the AFM-VBS transition line, which is consistent with the prediction of DQCP theory. Most surprisingly, we find that such an emergent O(4) symmetry holds for the whole QSL-VBS transition line as well. These findings reveal the intrinsic relationship between the QSL and DQCP from categorical symmetry point of view, and strongly constrain the quantum field theory description of the QSL phase. The phase diagram and critical exponents presented in this paper are of direct relevance to future experiments on frustrated magnets and cold atom systems.

Association of metabolic syndrome conditions with risk of second primary uterine cancer in breast cancer survivors.

PURPOSE: Uterine cancer risk is high in breast cancer survivors. Although breast cancer and uterine cancer share some common epidemiological risk factors, association of metabolic syndrome with incident uterine cancer in breast cancer survivors is under-studied. We evaluated the association of metabolic syndrome conditions with second primary uterine cancer in breast cancer survivors. METHODS: In this retrospective cohort study, 37,303 breast cancer patients diagnosed between 2008 and 2020 at Kaiser Permanente Southern California, an integrated healthcare system, were included. Data on cancer-related variables, sociodemographic, and clinical variables were extracted from KPSC's Surveillance, Epidemiology, and End Results (SEER)-affiliated cancer registry and electronic health records, as appropriate. Patients were followed from breast cancer diagnosis until 12/31/2021 for incident uterine cancer. Proportional hazards regression was used to report association [HR (95% CI)] between metabolic conditions and uterine cancer. RESULTS: More than half (53.1%) of the breast cancer survivors had 1-2 metabolic conditions; 19.4% had 3 + , while 27. 5% had no metabolic conditions. Median time to follow-up was 5.33 years and 185 (0.5%) patients developed second primary uterine cancer. Obesity was associated with an elevated uterine cancer risk in the adjusted model [HR (95% CI) 1.64 (1.20-2.25)]. Having 1-2 metabolic conditions (versus none) was not associated with increased uterine cancer risk [adjusted HR (95% CI) 1.24 (0.85-1.82)]; however, there was an increased uterine cancer risk with 3 + metabolic conditions [adjusted HR (95% CI) 1.82 (1.16-2.87)]. CONCLUSION: Although not statistically significant, we found a trend demonstrating greater uterine cancer risk by increasing numbers of metabolic syndrome conditions in breast cancer survivors.

[Total triterpenes of Euphorbium alleviates rheumatoid arthritis via Nrf2/HO-1/GPX4 pathway].

This study aims to investigate the effect and mechanism of total triterpenes of Euphorbium in treating rheumatoid arthritis(RA). The rat model of RA was established with Freund's complete adjuvant(FCA). Male rats were randomly assigned into control, model, Tripterygium glycosides(7.5 mg·kg~(-1)), and low-, medium-, and high-dose total triterpenes of Euphorbium(32, 64, and 128 mg·kg~(-1), respectively) groups, with 10 rats in each group. In other groups except the control group, 0.2 mL FCA was injected into the right hind toe. Rats in the intervention groups were administrated with corresponding drugs by gavage, and the control group and the model group with the same volume of 0.5% CMC-Na solution once a day. During the treatment period, the swelling degree of the hind paw was measured and the arthritis was scored until day 30. At the end of drug administration, the pathological changes of the joint tissue were observed by hematoxylin-eosin staining. The content of malondialdehyde(MDA), glutathione(GSH), and Fe~(2+) and the activity of superoxide dismutase(SOD) in the joint tissue were measured by biochemical colorimetry. RT-PCR was performed to determine the mRNA levels of nuclear factor erythroid 2-related factor 2(Nrf2), glutathione peroxidase 4(GPX4), and acyl-CoA synthetase long chain family member 4(ACSL4) in the joint tissue. Western blot was employed to determine the protein levels of Nrf2, Kelch-like ECH-associated protein 1(Keap1), heme oxygenase-1(HO-1), NAD(P)H quinone oxidoreductase 1(NQO1), SOD2, GPX4, and ACSL4 in the joint tissue. The results showed that the treatment with Tripterygium glycosides(7.5 mg·kg~(-1)) and total triterpenes of Euphorbium(32, 64, and 128 mg·kg~(-1)) alleviated the swelling degree of bilateral hind limbs, decreased the arthritis score, reduced joint tissue lesions and the content of MDA and Fe~(2+) in the joint tissue, and increased GSH content and SOD activity. Furthermore, the interventions up-regulated the protein and mRNA levels of Nrf2 and GPX4, down-regulated the protein and mRNA levels of ACSL4, and up-regulated the protein levels of Keap1, NQO1, HO-1, and SOD2 in the Nrf2/HO-1/GPX4. In summary, the total triterpenes of Euphorbium can treat RA by inhibiting lipid peroxidation and abnormal ferroptosis, which may involve the Nrf2/HO-1/GPX4 signaling pathway.

Effect of graphene on soybean root colonization by Bradyrhizobium strains.

Legume crops such as soybean obtain a large portion of their nitrogen nutrition through symbiotic nitrogen fixation by diazotrophic rhizobia bacteria in root nodules. However, nodule occupancy by low-capacity nitrogen-fixing rhizobia can lead to lower-than-optimal levels of nitrogen fixation. Seed/root coating with engineered materials such as graphene-carrying biomolecules that may promote specific attraction/attachment of desirable bacterial strains is a potential strategy that can help overcome this rhizobia competition problem. As a first step towards this goal, we assessed the impact of graphene on soybean and Bradyrhizobium using a set of growth, biochemical, and physiological assays. Three different concentrations of graphene were tested for toxicity in soybean (50, 250, and 1,000 mg/l) and Bradyrhizobia (25, 50, and 100 mg/l). Higher graphene concentrations (250 mg/l and 1,000 mg/l) promoted seed germination but slightly delayed plant development. Spectrometric and microscopy assays for hydrogen peroxide and superoxide anion suggested that specific concentrations of graphene led to higher levels of reactive oxygen species in the roots. In agreement, these roots also showed higher activities of antioxidant enzymes, catalase, and ascorbate peroxidase. Conversely, no toxic effects were detected on Bradyrhizobia treated with graphene, and neither did they have higher levels of reactive oxygen species. Graphene treatments at 250 mg/l and 1,000 mg/l significantly reduced the number of nodules, but rhizobia infection and the overall nitrogenase activity were not affected. Our results show that graphene can be used as a potential vehicle for seed/root treatment.

NtMYB1 and NtNCED1/2 control abscisic acid biosynthesis and tepal senescence in Chinese narcissus (Narcissus tazetta).

Chinese narcissus (Narcissus tazetta var. chinensis cv. 'Jinzhanyintai') is one of the 10 most famous traditional flowers of China, having a beautiful and highly ornamental flower with a rich fragrance. However, the flower longevity affects its commercial appeal. While petal senescence in Narcissus is ethylene-independent and abscisic acid-dependent, the regulatory mechanism has yet to be determined. In this study, we identified a R2R3-MYB gene (NtMYB1) from Narcissus tazetta and generated oeNtMYB1 and Ntmyb1 RNA interference mutants in Narcissus as well as an oeNtMYB1 construct in Arabidopsis. Overexpressing NtMYB1 in Narcissus or Arabidopsis led to premature leaf yellowing, an elevated level of total carotenoid, a reduced level of chlorophyll b, and a decrease in photosystem II fluorescence (Fv/Fm). A dual-luciferase assay and chromatin immunoprecipitation-quantitative PCR revealed that NtMYB1 directly binds to the promoter of NtNCED1 or NtNCED2 and activates NtNCED1/2 gene expression both in vitro and in vivo. Moreover, overexpressing NtMYB1 accelerated abscisic acid biosynthesis, up-regulated the content of zeatin and abscisic acid, and down-regulated the level of ß-carotene and gibberellin A1, leading to petal senescence and leaf yellowing in Narcissus. This study revealed a regulatory process that is fundamentally different between non-photosynthetic organs and leaves.

Insight into the enhancement effect of amino functionalized carbon nanotubes on the H2S removal performance of nanofluid system.

By constructing nanofluid system, trace functionalized nanoparticles can significantly enhance the absorption performance of basic liquid. In this work, amino functionalized carbon nanotubes (ACNTs) and carbon nanotubes (CNTs) were introduced into alkaline deep eutectic solvents to build nanofluid systems and used for the dynamic absorption of H2S. The experiment results showed that the introduction of nanoparticles can significantly enhance the H2S removal performance of original liquid. When performing H2S removal experiments, the optimal mass concentrations of ACNTs versus CNTs were 0.05 % and 0.01 %, respectively. The characterization showed that the surface morphology and structure of the nanoparticles unchanged significantly during the absorption-regeneration process. A double mixed gradientless gas-liquid reactor was used to explore the gas-liquid absorption kinetics characteristics of the nanofluid system. It was found that the gas-liquid mass transfer rate increased significantly after the addition of nanoparticles. The highest total mass transfer coefficient of the nanofluid system of ACNTs was increased to more than 400 % of the value before the addition of nanoparticles. The analysis showed that the shuttle effect and hydrodynamic effect of nanoparticles play important role in the process of enhancing gas-liquid absorption, and the amino functionalization enhanced the shuttle effect of nanoparticles significantly.

Analysis of Multimorbidity of Moderate to Severe Allergic Rhinitis in Children: A Real-World Study.

INTRODUCTION: Allergic rhinitis (AR) in children is associated with various comorbidities, posing challenges for treatment and management. There have been few investigations of these multimorbidities in Chinese children with AR. Here, we investigated the prevalence of multimorbidities in children with moderate to severe AR and analyzed the influencing factors using real-world data. METHODS: In total, 600 children who visited the outpatient clinic of our hospital and were diagnosed with moderate-severe AR were prospectively enrolled. All children underwent allergen detection and electronic nasopharyngoscopy. Parents or guardians completed a questionnaire that included age, sex, mode of delivery, feeding pattern, and familial history of allergy. The multimorbidities investigated included atopic dermatitis (AD), asthma, allergic conjunctivitis (AC), chronic rhinosinusitis (CRS), adenoid hypertrophy (AH), tonsil hypertrophy (TH), recurrent epistaxis, and recurrent respiratory tract infections (RRTIs). RESULTS: The AR multimorbidities reported in children were as follows: recurrent epistaxis (46.5%), AC (46.3%), AD (40.7%), asthma (22.5%), RRIs (21.3%), CRS (20.5%), AH (19.7%), and TH (12.5%). In univariate logistic regression analysis, age (<6 years), birth mode, familial history of allergy, and single dust mite allergy were associated with AR multimorbidity (p < 0.05). Multivariate logistic regression revealed that a familial history of allergy was an independent risk factor for AC (odds ratio [OR] = 1.539, 95% confidence interval [CI]: 1.104-2.145) and AH (OR = 1.506, 95% CI: 1.000-2.267) (p < 0.05). Age (<6 years) was independently associated with the risk of AD (OR = 1.405, 95% CI: 1.003-1.969) and RRTIs (OR = 1.869, 95% CI: 1.250-2.793) (p < 0.05), cesarean section with AR and CRS risk (OR = 1.678, 95% CI: 1.100-2.561), and single dust mite allergy with asthma (OR = 1.590, 95% CI: 1.040-2.432) and CRS (OR = 1.600, 95% CI: 1.018-2.515) risk (p < 0.05). Further, non-dust mite allergy was independently associated with AR and CRS (OR = 2.056, 95% CI: 1.084-3.899). CONCLUSION: AR was found to be accompanied by different comorbidities, including both allergic and non-allergic comorbidities, complicating disease treatment. These findings demonstrated that age (<6 years), familial history of allergy, types of allergens, and cesarean section were risk factors for different multimorbidities associated with AR.

A CNN-based four-layer DOI encoding detector using LYSO and BGO scintillators for small animal PET imaging.

Objective. We propose a novel four-layer depth-of-interaction (DOI) encoding phoswich detector using lutetium-yttrium oxyothosilicate (LYSO) and bismuth germanate (BGO) scintillator crystal arrays for high sensitivity and high spatial resolution small animal PET imaging.Approach. The detector was comprised of a stack of four alternating LYSO and BGO scintillator crystal arrays coupled to an 8 × 8 multi-pixel photon counter (MPPC) array and read out by a PETsys TOFPET2 application specific integrated circuit. The four layers from the top (gamma ray entrance) to the bottom (facing the MPPC) consisted of a 24 × 24 array of 0.99 × 0.99 × 6 mm3LYSO crystals, a 24 × 24 array of 0.99 × 0.99 × 6 mm3BGO crystals, a 16 × 16 array of 1.53 × 1.53 × 6 mm3LYSO crystals and a 16 × 16 array of 1.53 × 1.53 × 6 mm3BGO crystals.Main results. Events that occurred in the LYSO and BGO layers were first separated by measuring the pulse energy (integrated charge) and duration (time over threshold (ToT)) from the scintillation pulses. Convolutional neural networks (CNNs) were then used to distinguish between the top and lower LYSO layers and between the upper and bottom BGO layers. Measurements with the prototype detector showed that our proposed method successfully identified events from all four layers. The CNN models achieved a classification accuracy of 91% for distinguishing the two LYSO layers and 81% for distinguishing the two BGO layers. The measured average energy resolution was 13.1% ± 1.7% for the top LYSO layer, 34.0% ± 6.3% for the upper BGO layer, 12.3% ± 1.3% for the lower LYSO layer, and 33.9% ± 6.9% for the bottom BGO layer. The timing resolution between each individual layer (from the top to the bottom) and a single crystal reference detector was 350 ps, 2.8 ns, 328 ps, and 2.1 ns respectively.Significance. In conclusion, the proposed four-layer DOI encoding detector achieved high performance and is an attractive choice for next-generation high sensitivity and high spatial resolution small animal positron emission tomography systems.

Rearrangement of GO nanosheets with inner and outer forces under high-speed spin for supercapacitor.

The self-standing graphene membranes are considered as ideal electrode materials for supercapacitors. However, maintaining highly regularized and uniform graphene membranes with satisfied electrochemical performance is still a challenge. Herein, with the chelation of metal cation and the radial shear force introduced by high-speed spinning, the uniform interlayer channels and shrunken cracks between adjacent nanosheets can be achieved in the metal-intercalated graphene oxide (GO) membranes, thus realizing regularization both in normal and radial direction. With the promotion in electron transfer and electrolyte penetration, the iron cross-linked GO membrane with spin coating for 40 cycles exhibits a high specific capacitance (427 F g-1 at 1 A g-1) and rate capability (42.6% capacitance retention from 1 to 40 A g-1), as well as excellent cyclic capability (90.5% capacitance retention after 20,000 cycles). Particularly, a 21% increasement in capacitance can be achieved after high-speed spinning treatment. Moreover, the spin regularization strategy can be extended to GO membranes cross-linked by various multi-valence metal cations, the electrochemical performance of metal-cation cross-linked GO membrane electrodes after high-speed spinning treatment can also be improved obviously. Therefore, this paper provides a novel method to fabricate highly ordered GO membranes with promising electrochemical performance, which presents an immense potential application in membrane materials applied in energy storage, separation and catalysis.

Tuning Piezoelectricity via Thermal Annealing at a Freestanding Ferroelectric Membrane.

Tuning the ferroelectric domain structure by a combination of elastic and electrostatic engineering provides an effective route for enhanced piezoelectricity. However, for epitaxial thin films, the clamping effect imposed by the substrate does not allow aftergrowth tuning and also limits the electromechanical response. In contrast, freestanding membranes, which are free of substrate constraints, enable the tuning of a subtle balance between elastic and electrostatic energies, giving new platforms for enhanced and tunable functionalities. Here, highly tunable piezoelectricity is demonstrated in freestanding PbTiO3 membranes, by varying the ferroelectric domain structures from c-dominated to c/a and a domains via aftergrowth thermal treatment. Significantly, the piezoelectric coefficient of the c/a domain structure is enhanced by a factor of 2.5 compared with typical c domain PbTiO3. This work presents a new strategy to manipulate the piezoelectricity in ferroelectric membranes, highlighting their great potential for nano actuators, transducers, sensors and other NEMS device applications.

Isorhynchophylline inhibits inflammatory responses in endothelial cells and macrophages through the NF-κB/NLRP3 signaling pathway.

BACKGROUND: Atherosclerosis is a chronic inflammatory disease of arterial wall, which is closely related to inflammatory reaction. In this study, the anti-inflammatory effect of isorhynchophylline was studied by NF- κB / NLRP3 pathway. METHODS: (1) ApoE-/- mice were fed with high-fat diet to establish atherosclerotic model, while C57 with the same genetic background was fed with common diet as control group. Body weight was recorded and blood lipids were detected. The expression of NLRP3, NF-κB, IL-18 and Caspase-1 in aorta was detected by Western-Blot and PCR, and plaque formation was detected by HE and oil red O staining. (2) Lipopolysaccharide interfered with Human Umbilical Vein Endothelial Cells (HUVECs) and RAW264.7 to form inflammatory model, and was treated with isorhynchophylline. The expression of NLRP3, NF-κB, IL-18 and Caspase-1 in aorta was detected by Western-Blot and PCR, and the ability of cell migration was detected by Transwell and scratch test. RESULTS: (1) the expression of NLRP3, NF- κB, IL-18 and Caspase-1 in aorta of model group was higher than that of control group, and plaque formation was obvious. (2) the expressions of NLRP3, NF- κB, IL-18 and Caspase-1 in HUVECs and RAW264.7 model groups were higher than those in control group, while isorhynchophylline decreased their expression and enhanced cell migration ability. CONCLUSION: Isorhynchophylline can reduce the inflammatory reaction induced by lipopolysaccharide and promote the ability of cell migration.

Selective Reductive Coupling of Vinyl Azaarenes and Alkynes via Photoredox Cobalt Dual Catalysis.

A visible light-induced Co-catalyzed highly regio- and stereoselective reductive coupling of vinyl azaarenes and alkynes has been developed. Notably, Hünig's base together with simple ethanol has been successfully applied as the hydrogen sources instead of commonly used Hantzsch esters in this catalytic photoredox reaction. This approach has considerable advantages for the straightforward synthesis of stereodefined multiple substituted alkenes bearing an azaarene motif, such as excellent regioselectivity (>20 : 1 for >30 examples) and stereoselectivity (>20 : 1 E/Z), broad substrate scope and good functional group compatibility under mild reaction conditions, which has been utilized in the concise synthesis of natural product monomorine I. A reasonable catalytic reaction pathway involving protolysis of the cobaltacyclopentene intermediate has been proposed based on the mechanistic studies.

Gapless quantum spin liquid and global phase diagram of the spin-1/2 J1-J2 square antiferromagnetic Heisenberg model.

The nature of the zero-temperature phase diagram of the spin-1/2J1-J2 Heisenberg model on a square lattice has been debated in the past three decades, and it remains one of the fundamental problems unsettled in the study of quantum many-body theory. By using the state-of-the-art tensor network method, specifically, the finite projected entangled pair state (PEPS) algorithm, to simulate the global phase diagram of the J1-J2 Heisenberg model up to 24×24 sites, we provide very solid evidences to show that the nature of the intermediate nonmagnetic phase is a gapless quantum spin liquid (QSL), whose spin-spin and dimer-dimer correlations both decay with a power law behavior. There also exists a valence-bond solid (VBS) phase in a very narrow region 0.56≲J2/J1≤0.61 before the system enters the well known collinear antiferromagnetic phase. We stress that we make the first detailed comparison between the results of PEPS and the well-established density matrix renormalization group (DMRG) method through one-to-one direct benchmark for small system sizes, and thus give rise to a very solid PEPS calculation beyond DMRG. Our numerical evidences explicitly demonstrate the huge power of PEPS for highly frustrated spin systems. Finally, an effective field theory is also proposed to understand the physical nature of the discovered gapless QSL and its relation to deconfined quantum critical point (DQCP).

Electromagnetic Source Imaging via a Data-Synthesis-Based Convolutional Encoder-Decoder Network.

Electromagnetic source imaging (ESI) requires solving a highly ill-posed inverse problem. To seek a unique solution, traditional ESI methods impose various forms of priors that may not accurately reflect the actual source properties, which may hinder their broad applications. To overcome this limitation, in this article, a novel data-synthesized spatiotemporally convolutional encoder-decoder network (DST-CedNet) method is proposed for ESI. The DST-CedNet recasts ESI as a machine learning problem, where discriminative learning and latent-space representations are integrated in a CedNet to learn a robust mapping from the measured electroencephalography/magnetoencephalography (E/MEG) signals to the brain activity. In particular, by incorporating prior knowledge regarding dynamical brain activities, a novel data synthesis strategy is devised to generate large-scale samples for effectively training CedNet. This stands in contrast to traditional ESI methods where the prior information is often enforced via constraints primarily aimed for mathematical convenience. Extensive numerical experiments as well as analysis of a real MEG and epilepsy EEG dataset demonstrate that the DST-CedNet outperforms several state-of-the-art ESI methods in robustly estimating source signals under a variety of source configurations.

Constructing a Double Alternant "Rigid-Flexible" Structure for Simultaneously Strengthening and Toughening the Interface of Carbon Fiber/Epoxy Composites.

An optimized "rigid-flexible" structure with multistage gradient modulus was constructed on carbon fiber (CF) surface via chemical grafting using "flexible" polyethyleneimine (PEI) and "rigid" polydopamine (PDA) between "rigid" CF and "flexible" epoxy (EP) to elaborate a double alternant "rigid-flexible" structure for simultaneously strengthening and toughening CF/EP composites. PDA and PEI polymers can greatly enhance the roughness and wettability of CF surfaces, further strengthening the mechanical interlocking and chemical interactions between CFs and epoxy. Besides, the "rigid-flexible" structure endows the interface with a gradient transition modulus, which could uniformly transfer internal stress and effectively avoid the stress concentration. Moreover, the double alternant "rigid-flexible" could buffer the external loading, induce more micro cracks and propagation paths and, thereby, consume more energy during the destruction of the composite. The interfacial shear strength, interlaminar shear strength, impact strength increased by 80.2%, 23.5% and 167.2%, and the fracture toughness improved by 227.2%, compared with those of the unmodified CF composite, respectively. This creative strategy and design afford a promising guidance for the preparation and production of advanced CF/EP structural materials with high strength and toughness.

Constructing a Superior Interfacial Microstructure on Carbon Fiber for High Interfacial and Mechanical Properties of Epoxy Composites.

The interface quality is crucial for the properties of carbon fiber-reinforced polymer- matrix composites (CFRPs). In order to improve the interfacial and mechanical properties of CFRPs, a superior gradient modulus interfacial microstructure is constructed on the carbon fiber (CF) surface by chemically grafting a self-assembly carboxyl-terminated hyperbranched polymer (HP-COOH). A monofilament debonding test, a short beam shear test, an impact test and a dynamic mechanical thermal analysis (DMTA) were conducted to investigate the properties of the modified composite. Prominent improvements of 79.6% for the interfacial shear strength, 51.5% for the interlaminar shear strength, and 49.2% for the impact strength, as well as superior heat-resistance properties are achieved for composites with the gradient modulus interface over those of the untreated CF composites. The mechanism for performance improvement is mainly attributed to the enhanced CF surface energy, mechanical interlocking, and chemical bonding interactions. In particular, an atomic force microscopy (AFM) test proved that the gradient modulus interfacial microstructure formed by HP-COOH could widen the interface layer thickness and buffer the sharp variations in the modulus from CF to resin, thereby transmitting an external force and reducing the stress concentration. This work provides a facile and efficient strategy for constructing a superior and versatile interface for high- performance composites.