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Intercalated layered materials offer distinctive properties and serve as precursors for important two-dimensional (2D) materials. However, intercalation of non-van der Waals structures, which can expand the family of 2D materials, is difficult. We report a structural editing protocol for layered carbides (MAX phases) and their 2D derivatives (MXenes). Gap-opening and species-intercalating stages were respectively mediated by chemical scissors and intercalants, which created a large family of MAX phases with unconventional elements and structures, as well as MXenes with versatile terminals. The removal of terminals in MXenes with metal scissors and then the stitching of 2D carbide nanosheets with atom intercalation leads to the reconstruction of MAX phases and a family of metal-intercalated 2D carbides, both of which may drive advances in fields ranging from energy to printed electronics., Funding Agencies|Key R&D Projects of Zhejiang Province; Leading Innovative and Entrepreneur Team Introduction Program of Zhejiang; International Partnership Program of Chinese Academy of Sciences [2022C01236]; Advanced Energy Science and Technology Guangdong Laboratory [2019R01003]; Ningbo Top-talent Team Program [174433KYSB20190019]; Ningbo "3315 plan" [HND20TDTHGC00]; National Natural Science Foundation of China; China Postdoctoral Science Foundation [2018A-03-A]; Knut and Alice Wallenberg Foundation through the Wallenberg Academy Fellows Program [21671195, 52172254, 52250005, 52202325, U2004212]; Wallenberg Scholar Program [2020M680082]; Swedish National Infrastructure in Advanced Electron Microscopy [KAW 2020.0196]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoeping University SFO-Mat-LiU [KAW 2019.0290]; US National Science Foundation [2021-00171, RIF21-0026]; [2009 00971]; [DMR-2041050]

To reduce the repetitive and complex work of instructors, exam paper generation (EPG) technique has become a salient topic in the intelligent education field, which targets at generating high-quality exam paper automatically according to instructor-specified assessment criteria. The current advances utilize the ability of heuristic algorithms to optimize several well-known objective constraints, such as difficulty degree, number of questions, etc., for producing optimal solutions. However, in real scenarios, considering other equally relevant objectives (e.g., distribution of exam scores, skill coverage) is extremely important. Besides, how to develop an automatic multi-objective solution that finds an optimal subset of questions from a huge search space of large-sized question datasets and thus composes a high-quality exam paper is urgent but non-trivial. To this end, we skillfully design a reinforcement learning guided Multi-Objective Exam Paper Generation framework, termed MOEPG, to simultaneously optimize three exam domain-specific objectives including difficulty degree, distribution of exam scores, and skill coverage. Specifically, to accurately measure the skill proficiency of the examinee group, we first employ deep knowledge tracing to model the interaction information between examinees and response logs. We then design the flexible Exam Q-Network, a function approximator, which automatically selects the appropriate question to update the exam paper composition process. Later, MOEPG divides the decision space into multiple subspaces to better guide the updated direction of the exam paper. Through extensive experiments on two real-world datasets, we demonstrate that MOEPG is feasible in addressing the multiple dilemmas of exam paper generation scenario.

As is well known, differential algebraic equations (DAEs), which are able to describe dynamic changes and underlying constraints, have been widely applied in engineering fields such as fluid dynamics, multi-body dynamics, mechanical systems and control theory. In practical physical modeling within these domains, the systems often generate high-index DAEs. Classical implicit numerical methods typically result in varying order reduction of numerical accuracy when solving high-index systems.~Recently, the physics-informed neural network (PINN) has gained attention for solving DAE systems. However, it faces challenges like the inability to directly solve high-index systems, lower predictive accuracy, and weaker generalization capabilities. In this paper, we propose a PINN computational framework, combined Radau IIA numerical method with a neural network structure via the attention mechanisms, to directly solve high-index DAEs. Furthermore, we employ a domain decomposition strategy to enhance solution accuracy. We conduct numerical experiments with two classical high-index systems as illustrative examples, investigating how different orders of the Radau IIA method affect the accuracy of neural network solutions. The experimental results demonstrate that the PINN based on a 5th-order Radau IIA method achieves the highest level of system accuracy. Specifically, the absolute errors for all differential variables remains as low as $10^{-6}$, and the absolute errors for algebraic variables is maintained at $10^{-5}$, surpassing the results found in existing literature. Therefore, our method exhibits excellent computational accuracy and strong generalization capabilities, providing a feasible approach for the high-precision solution of larger-scale DAEs with higher indices or challenging high-dimensional partial differential algebraic equation systems.

Two-dimensional (2D) materials offer advantages that their 3D counterparts do not. The conventional method for the bulk synthesis of 2D materials has predominantly been through etching layered solids. Herein, we convert - through a bottom-up approach - 10 binary and ternary titanium carbides, nitrides, borides, phosphides, and silicides into 2D flakes by immersing them in a tetramethylammonium hydroxide solution at temperatures in the 25-85 degrees C range. Based on X-ray diffraction, density functional theory, X-ray photoelectron, electron energy loss, Raman, X-ray absorption near edge structure spectroscopies, transmission and scanning electron microscope images and selected area diffraction, we conclude that the resulting flakes are carbon containing anatase-based layers that are, in turn, comprised of approximate to 6 x 10 angstrom(2) nanofilaments in cross-section some of which are few microns long. Electrodes made from some of these films performed well in lithium-ion and lithium-sulphur systems. These materials also reduce the viability of cancer cells thus showing potential in biomedical applications. Synthesizing 2D materials, at near ambient conditions, with non-layered, inexpensive, green precursors (e.g., TiC) is paradigm shifting and will undoubtedly open new and exciting avenues of research and applications., Funding Agencies|Ceramics Division of NSF [1740795]; Murata Manufacturing Co. Ltd of Japan; WPI TRIAD Seed Grant; Knut and Alice Wallenberg (KAW) Foundation; Drexel University; Swedish Foundation for Strategic Research (SSF) through the Research Infrastructure Fellow program [RIF 14-0074]; NSF [1919177]

Han Zhang,1 Qinghui Niu,1 Kun Liang,2 Xuesen Li,3 Jing Jiang,2 Cheng Bian2 1Department of Liver Center, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, People’s Republic of China; 2Department of Infectious Diseases, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, People’s Republic of China; 3Department of Spine Surgery, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, People’s Republic of ChinaCorrespondence: Qinghui NiuDepartment of Liver Center, The Affiliated Hospital of Qingdao University, No. 59 Haier Road, Qingdao, Shandong, 266100, People’s Republic of ChinaTel +86-0532-82915998Email qinghuiniu@163.comPurpose: Nonalcoholic fatty liver disease (NAFLD) is closely related to lipid metabolism and insulin resistance. The current research mainly attempted to verify the clinical value of LncRNA plasmacytoma variant translocation 1 (PVT1), and whether microRNA regulates lipid metabolism and insulin resistance to participate in NAFLD.Patients and Methods: 81 patients with NAFLD and 78 healthy individuals were enrolled in this study. In addition, C57BL/6 mice were fed a high-fat diet to establish NAFLD model in vivo. Serum PVT1 and miR-20a-5p expression in NAFLD patients and mice were assessed by RT-qPCR. ROC curves determine the diagnostic value of PVT1 and miR-20a-5p. NAFLD mice were subjected to IPGTT to detect changes in insulin sensitivity, and the common indicators of lipid metabolism and insulin resistance were also evaluated. Dual-luciferase reporter assay verified the regulation mechanism of PVT1 and miR-20a-5p.Results: PVT1 was upregulated in NAFLD patients and mice, while miR-20a-5p was decreased. Their expression trends were similar in patients with HOMA-IR ≥ 2.5. What’s more, miR-20a-5p, FBG, ALT, and HOMA-IR were independently correlated with PVT1. And PVT1 and miR-20a-5p show high clinical diagnostic value. Bodyweight, insulin sensitivity, lipid metabolism inductors were increased in NAFLD

Long-range and fast transport of coherent excitons is important for the development of high-speed excitonic circuits and quantum computing applications. However, most of these coherent excitons have only been observed in some low-dimensional semiconductors when coupled with cavities, as there are large inhomogeneous broadening and dephasing effects on the transport of excitons in their native states in materials. Here, by confining coherent excitons at the 2D quantum limit, we first observed molecular aggregation-enabled 'supertransport' of excitons in atomically thin two-dimensional (2D) organic semiconductors between coherent states, with a measured high effective exciton diffusion coefficient of ~346.9 cm2/s at room temperature. This value is one to several orders of magnitude higher than the values reported for other organic molecular aggregates and low-dimensional inorganic materials. Without coupling to any optical cavities, the monolayer pentacene sample, a very clean 2D quantum system (~1.2 nm thick) with high crystallinity (J-type aggregation) and minimal interfacial states, showed superradiant emission from Frenkel excitons, which was experimentally confirmed by the temperature-dependent photoluminescence (PL) emission, highly enhanced radiative decay rate, significantly narrowed PL peak width and strongly directional in-plane emission. The coherence in monolayer pentacene samples was observed to be delocalised over ~135 molecules, which is significantly larger than the values (a few molecules) observed for other organic thin films. In addition, the supertransport of excitons in monolayer pentacene samples showed highly anisotropic behaviour. Our results pave the way for the development of future high-speed excitonic circuits, fast OLEDs, and other optoelectronic devices.

One of the most fundamental parameters of any photovoltaic material is its quasi-Fermi level splitting (∆µ) under illumination. This quantity represents the maximum open-circuit voltage (Voc) that a solar cell fabricated from that material can achieve. Herein, a contactless, nondestructive method to quantify this parameter for atomically thin 2D transition metal dichalcogenides (TMDs) is reported. The technique is applied to quantify the upper limits of Voc that can possibly be achieved from monolayer WS2, MoS2, WSe2, and MoSe2-based solar cells, and they are compared with state-of-the-art perovskites. These results show that Voc values of ≈1.4, ≈1.12, ≈1.06, and ≈0.93 V can be potentially achieved from solar cells fabricated from WS2, MoS2, WSe2, and MoSe2 monolayers at 1 Sun illumination, respectively. It is also observed that ∆µ is inhomogeneous across different regions of these monolayers. Moreover, it is attempted to engineer the observed ∆µ heterogeneity by electrically gating the TMD monolayers in a metal-oxide-semiconductor structure that effectively changes the doping level of the monolayers electrostatically and improves their ∆µ heterogeneity. The values of ∆µ determined from this work reveal the potential of atomically thin TMDs for high-voltage, ultralight, flexible, and eye-transparent future solar cells.

In dark matter direct detection experiments, neutron is a serious source of background, which can mimic the dark matter-nucleus scattering signals. In this paper, we present an improved evaluation of the neutron background in the PandaX-II dark matter experiment by a novel approach. Instead of fully relying on the Monte Carlo simulation, the overall neutron background is determined from the neutron-induced high energy signals in the data. In addition, the probability of producing a dark-matter-like background per neutron is evaluated with a complete Monte Carlo generator, where the correlated emission of neutron(s) and $\gamma$(s) in the ($\alpha$, n) reactions and spontaneous fissions is taken into consideration. With this method, the neutron backgrounds in the Run 9 (26-ton-day) and Run 10 (28-ton-day) data sets of PandaX-II are estimated to be 0.66$\pm$0.24 and 0.47$\pm$0.25 events, respectively., Comment: 9 pages, 9 figures, 7 tables; version2 accepted by Sci. China Phys. Mech. Astron

We report the Neutrino-less Double Beta Decay (NLDBD) search results from PandaX-II dual-phase liquid xenon time projection chamber. The total live time used in this analysis is 403.1 days from June 2016 to August 2018. With NLDBD-optimized event selection criteria, we obtain a fiducial mass of 219 kg of natural xenon. The accumulated xenon exposure is 242 kg$\cdot$yr, or equivalently 22.2 kg$\cdot$yr of $^{136}$Xe exposure. At the region around $^{136}$Xe decay Q-value of 2458 keV, the energy resolution of PandaX-II is 4.2%. We find no evidence of NLDBD in PandaX-II and establish a lower limit for decay half-life of 2.4 $ \times 10^{23} $ yr at the 90% confidence level, which corresponds to an effective Majorana neutrino mass $m_{\beta \beta} < (1.3 - 3.5)$ eV. This is the first NLDBD result reported from a dual-phase xenon experiment., Comment: Submitted to Chinese Physics C

The ability of black Carp Mylopharyngodon piceus, to utilize high levels of dietary carbohydrate was assessed using artificial purified feed, containing normal (20%, NS group) and high (40%, HS group) levels of digestible carbohydrate. After a 10 week feeding trial, specific growth rate, weight gain rate, and protein efficiency ratio of the HS group were significantly lower (P<0.05). The 40% carbohydrate diet significantly influenced the crude protein and crude fat levels in the muscle tissue (P<0.05). Plasma cortisol of the HS group was significantly lower (P<0.05), and levels of plasma triglycerides and total cholesterol were highly significantly lower (P<0.01). Hepatic superoxide dismutase concentrations of the HS group were lower (P<0.05), and contents of the carbohydrate metabolic enzyme, hepatic pyruvate kinase were highly significantly lower (P<0.01). Hepatic ultrastructure results show that the high carbohydrate diet induced sedimentation of glucose and fat in the hepatic cells, and ultrastructural damage was observed. Although Mylopharyngodon piceus are able to tolerate long-term feeding of the 40% carbohydrate diet, effects on growth and immunity were negative resulting in ultrastructural damage of the hepatic cells.

The present study was aimed at evaluating the effects of the feed additive curcumin on the growth and non-specific immune responses in juvenile Wuchang bream (Megalobrama amblycephala). Six experimental diets were formulated to contain graded curcumin levels (0, 15, 30, 60, 120 and 240 mg/kg of diet, respectively). After 60 days feeding trial, fish fed the 60 mg/kg curcumin diet had significantly higher weight gain rate (WGR) and specific growth rate (SGR), and significantly lower feed conversion ratio (FCR) than the control group. The number of leucocytes (WBC), interleukin-1 beta (IL-1β), tumor necrosis factor-α (TNF-α), alternative pathway of complement (ACH50), and respiratory burst activity increased with increasing dietary curcumin levels up to 60 mg/kg, and thereafter declined. Significantly lower alanine transaminase (ALT) and aspartate transaminase (AST) activities were observed in fish fed the 60 mg/kg curcumin diet compared to those in the control group. Fish fed with the diets containing 60 and 120 mg/kg curcumin had significantly higher TNF-α and ACH50 activities than those in the control, and the fish fed diets supplemented with 60 and 240 mg/kg curcumin had significantly higher IL-1β activities than those in the control. The results suggest that appropriate dietary curcumin supplementation (60 mg/kg curcumin of diet) significantly improved growth and non-specific immune responses in juvenile M. amblycephala.

An 8-week feeding trial was conducted to investigate the effects of dietary emodin supplementation on growth, non-specific immunity, and protection against Aeromonas hydrophila infection in juvenile Megalobrama amblycephala. A basal diet was supplemented with 0 (control), 15, 30, 60 and 120 mg emodin/kg to formulate five experimental diets. Each diet was randomly allocated to triplicate tanks of fish in a circulating water system (initial average weight 3.49±0.045g, 25 fish per tank). At the end of the feeding trial, fish fed the diet supplemented with 0 and 120 mg emodin/kg had lower weight gain (WG) and specific growth rate (SGR) than those in the other treatment groups, but no significant differences were observed among diets supplemented with emodin from 15 to 60 mg/kg. A significant increase on feed conversion ratio (FCR) of fish fed diet supplemented with 120 mg emodin/kg was observed. The white blood cell count (WBC), respiratory burst activity, superoxide dismutase (SOD) activity, myeloperoxidase (MPO) activity, malondialdehyde (MDA) content, and tumor necrosis factor-α (TNF-α) activity first increased and then decreased with increase of the dietary emodin levels. Fish fed the 30 mg emodin/kg supplemented diet had higher WBC, respiratory burst activity, SOD and TNF-α activity, and lower MDA content, than fish fed diets supplemented with 0 and 120 mg emodin/kg. In the bacteria challenge experiment with A. hydrophila, fish fed a diet supplemented with 30 and 60 mg/kg had a lower cumulative mortality rate than the control group. These results indicated that appropriate dietary emodin supplementation (especially 30 mg emodin/kg diet) could enhance the growth and immune responses of fish and improve resistance to infection by A. hydrophila.

Chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-seq) is rapidly replacing chromatin immunoprecipitation combined with genome-wide tiling array analysis (ChIP-chip) as the preferred approach for mapping transcription-factor binding sites and chromatin modifications. The state of the art for analyzing ChIP-seq data relies on using only reads that map uniquely to a relevant reference genome (uni-reads). This can lead to the omission of up to 30% of alignable reads. We describe a general approach for utilizing reads that map to multiple locations on the reference genome (multi-reads). Our approach is based on allocating multi-reads as fractional counts using a weighted alignment scheme. Using human STAT1 and mouse GATA1 ChIP-seq datasets, we illustrate that incorporation of multi-reads significantly increases sequencing depths, leads to detection of novel peaks that are not otherwise identifiable with uni-reads, and improves detection of peaks in mappable regions. We investigate various genome-wide characteristics of peaks detected only by utilization of multi-reads via computational experiments. Overall, peaks from multi-read analysis have similar characteristics to peaks that are identified by uni-reads except that the majority of them reside in segmental duplications. We further validate a number of GATA1 multi-read only peaks by independent quantitative real-time ChIP analysis and identify novel target genes of GATA1. These computational and experimental results establish that multi-reads can be of critical importance for studying transcription factor binding in highly repetitive regions of genomes with ChIP-seq experiments. © 2011 Chung et al.

Nowadays, GPS carrier-phase time and frequency transfer methods are applied more and more in the timing area because of their high ranging resolution, which corresponds to high time and frequency transfer precision. In this paper, we have built a GPS carrier-phase time and frequency transfer system preliminarily at the National Institute of Metrology (NIM). Several different time and frequency transfer experiments, including zero-baseline and long-baseline experiments with the same reference or the different references, conducted using GPS carrier phase with the GPS carrier-phase time and frequency transfer system by two different solution methods, were implemented and the experimental results are compared., Presented at the Precise Time and Time Interval (PTTI) Systems and Applications Meeting (41st Annual) held in Santa Ana Pueblo, NM on 16-19 Nov 2009. Published in the Proceedings of the Precise Time and Time Interval (PTTI) Systems and Applications Meeting (41st Annual), p111-120, 2009. The original document contains color images.