Impaired social reward processing in individuals with Internet gaming disorder and its relationship with early face perception.

Previous research has found that individuals with Internet gaming disorder (IGD) show different patterns of social function impairments in game-related and real-life social contexts. Impaired social reward processing may be the underlying mechanism according to the Social Motivation Theory. Thus, in this study, event-related potentials were recorded from 24 individuals with IGD and 24 healthy gamers during a social judgement task. We focused on reward positivity (RewP) elicited by game-related and real-life social rewards, and N170 elicited by game avatar faces and real faces. These indicators were used to explore the neurocognitive mechanism of impaired social reward processing in individuals with IGD and its relationship with early face perception. Results showed that (1) the RewP elicited by real-life social reward was considerably reduced in individuals with IGD relative to healthy gamers. (2) The N170 elicited by game avatar faces in individuals with IGD was larger than that elicited by real faces. However, the N170 was not associated with RewP in either group. (3) The score for IGD severity was correlated with the RewP elicited by real-life social reward and the N170 elicited by game avatar face. In conclusion, the present study suggests that the impaired social reward processing in individuals with IGD is mainly manifested in a decreased neural sensitivity to real-life social reward. Meanwhile, the reduced RewP elicited by real-life social reward and the enhanced N170 elicited by game avatar face might serve as potential biomarkers for IGD.

A New Stochastic Split-Step θ-Nonstandard Finite Difference Method for the Developed SVIR Epidemic Model with Temporary Immunities and General Incidence Rates.

In this paper, an SVIR epidemic model with temporary immunities and general incidence rates is constructed and analyzed. By utilizing Lyapunov functions, we prove the existence and uniqueness of the positive global solution of the constructed model, as well as the sufficient conditions of extinction and persistence of disease, are provided. Due to the difficulty of obtaining the analytical solution to our model, we construct two numerical schemes to generate an approximate solution to the model. The first one is called the split-step θ-Milstein (SSTM) method, and the second one is called the stochastic split-step θ-nonstandard finite difference (SSSNSFD) method, which is designed by merging split-step θ method with stochastic nonstandard finite difference method for the first time in this paper. Further, we prove the positivity, boundedness, and stability of the SSSTNSFD method. By employing the two mentioned methods, we support the validity of the studied theoretical results, as well, the effect of the length of immunity periods, parameters values of the incidence rates, and noise on the dynamics of the model are discussed and simulated. The increase in the size of time step size plays a vital role in revealing the method that preserves positivity, boundedness, and stability. To this end, a comparison between the proposed numerical methods is carried out graphically.

Influence of abstinence on automatic detection bias to gaming cues in individuals with Internet gaming disorder: Evidence from visual mismatch negativity.

Internet gaming disorder (IGD) has been classified by the DSM-5 as a condition for further study, and many studies have shown that the occurrence and maintenance of IGD and the automatic detection bias to gaming cues of individuals with IGD may be significantly related. However, whether abstinence, a common intervention method in behavioral addiction, can adjust the automatic detection bias in individuals with IGD and its underlying neural mechanisms is unclear. In this study, we investigated the effects of 7 days of abstinence from gaming on automatic detection bias, negative affect and craving in individuals with IGD with event-related potential technology. A total of 50 IGD subjects were recruited in this study and randomly divided into abstinence and control groups. Visual mismatch negativity (vMMN) was induced using a standard-deviant reversed oddball paradigm, and differences in automatic detection bias, negative affect, and craving between the two groups were recorded and compared at baseline, day 3, and day 7. The results showed that compared with baseline, vMMN, negative affect and craving were significantly enhanced on day 3 and significantly diminished on day 7 in the abstinence group but not in the control group, and the changes in vMMN were significantly correlated with changes in negative affect and craving in both groups. This study demonstrates that abstinence can restore automatic detection bias in individuals with IGD and that abstinence has to last for 7 days to have a significant effect, while recovery may be related to the negative affect and craving.

Spontaneous Polarity Flipping in a 2D Heterobilayer Induced by Fluctuating Interfacial Carrier Flows.

Polarity often refers to the charge carrier type of a semiconductor or the charging state of a functional group, generally dominating their functionality and performance. Herein we uncover a spontaneous and stochastic polarity-flipping phenomenon in monolayer WSe2, which randomly switches between the n-type and p-type states and is essentially triggered by fluctuating carrier flows from or to the adjacent WS2 monolayer. We have traced such fluctuating carrier flows by interfacial photocurrent measurements in a zero-bias two-terminal device. Such polarity flipping results in switching between the negative and positive correlations between the emission intensities of WS2 and WSe2 in the heterobilayer, which is further well-controlled by the electrostatic gate-tuning experiments in a capacitor-structure device. Our work not only demonstrates giant and intermittent carrier flows through long-range coupling in 2D heterostructures and a consequent spontaneous polarity flipping phenomenon but also provides a two-emitter system with a switchable correlation sign that could project future applications in optical logic devices.

Behavioral modification decreases approach bias in young adults with internet gaming disorder.

BACKGROUND: One of the key symptoms of Internet gaming disorder is the impulsive pursuit of Internet games, which causes individuals with this disorder to have a tendency to approach gaming cues. Dual processing theory states that this approach bias is caused by the suppression of reflective processing and the hyperactivity of impulsive processing. Therefore, reverse modification training for approach bias can suppress impulsive processing, thereby reducing or treating the disorder. METHOD: In this study, 48 individuals with Internet gaming disorder were selected and randomly assigned to the following two groups: the experimental group and the control group. The 24 participants in the experimental group received a 4-day stimulus-response compatibility (SRC) approach bias modification treatment, whereas the 24 participants in the control group received a corresponding SRC pseudomodification training. RESULTS: The approach response time of both groups to the gaming cues was significantly shorter than that to the neutral cues at baseline. After the modification, the response time of the experimental group to the gaming cues significantly increased, whereas the scores for Internet gaming disorder severity, anxiety level and craving significantly decreased. However, the control group subjects did not show these effects. CONCLUSION: The current results imply that individuals with Internet gaming disorder show approach bias toward Internet gaming cues, and SRC reverse modification training can significantly correct this bias and therefore have therapeutic effects to some extent.

Effect of the mobile phone-related background on inhibitory control of problematic mobile phone use: An event-related potentials study.

The present study aims to provide electrophysiological evidence for deficient inhibitory control in problematic mobile phone use and to investigate whether reduced inhibition is more pronounced during exposure to a mobile phone related background cue. A screen scale of smartphone addiction was completed by 227 college students, and finally an experimental group and a control group consisting of 20 problematic mobile phone users and 19 controls were included in the study. Event-related potentials were recorded during a backgrounded Go/NoGo task performed by those two groups, in which either a frequent Go signal (letter "M") or a rare NoGo signal (letter "W") was superimposed on three different background cues: neutral, mobile phone application-related and mobile phone using-related pictures. Results showed that problematic mobile phone users performed more commission errors than controls following mobile phone application background. Furthermore, problematic mobile phone users displayed a weaker NoGo P3 amplitude than controls on the mobile phone application background. The result might suggest that there is no general impairment of inhibitory control in problematic mobile phone use. The deficient inhibitory control on behavioral and psychophysiological level appeared merely in the mobile phone-related background. Such deficient stimuli-specific inhibitory control appears at the late stage of inhibitory control. Prevention programs should be designed to curtail exposure to the mobile phone-related stimulus and enhance cognitive control of potential problematic mobile phone users.

Automatic detection advantage of problematic Internet users for Wi-Fi signal cues and the moderating effect of negative affect: An event-related potential study.

Cognitive bias toward Internet-related cues is an important factor of the formation and maintenance of the addictive behavior of problematic Internet users (PIUs). The development of fiber-optic communication and smartphones has ushered human society into the era of wireless networks. The Wi-Fi signal, the symbol of wireless network connection, represents not only network access but also a channel for communication with others anywhere at any time. Therefore, the Wi-Fi signal cues should be an effective inducer of the addictive behaviors of PIUs. We used images of Wi-Fi signal as Internet-related cues to explore the automatic detection advantage of PIUs for these cues and to determine whether negative affect, another predisposing factor for addiction, can enhance this advantage. We utilized an intergroup design in this study. The PIU and control groups each comprised 30 participants and were randomly assigned to negative or neutral affect priming group. Mismatch negativity (MMN) was induced through the deviant-standard reverse oddball paradigm. Wi-Fi signal cues and neutral cues were used as standard and deviant stimuli, respectively. Results show that the MMN induced by Wi-Fi signal cues in the PIU group was larger than that in the control group. Meanwhile, the MMN induced by Wi-Fi signal cues was considerably enhanced in the PIU group under negative affect priming relative to that in the PIU group under neutral affect priming. Overall, PIUs have an automatic detection advantage for Wi-Fi signal cues, and negative affect can enhance this advantage. Our results suggest that the MMN elicited by Wi-Fi signal cues function as a sensitive neurobiological marker tracing the change of addiction motivation for PIUs.

Automatic Processing Advantage of Cartoon Face in Internet Gaming Disorder: Evidence From P100, N170, P200, and MMN.

Individuals with Internet gaming disorder (IGD) show deficits in face processing due to long-term Internet-game social activities based on cartoon faces in the popular online game "Strike of Kings." However, the abnormal neurocognitive mechanism of face recognition and processing in individuals with IGD has not been systematically explored. This study used event-related potential (ERP) methods and the reversed deviant-standard oddball paradigm to comprehensively compare four ERP components, namely, P100, N170, P200, and mismatch negativity (MMN), induced in the unconscious and automatic processing of realistic and cartoon faces in individuals with IGD. Results showed that, with respect to cartoon faces, individuals with IGD exhibited not only P100, P200 and MMN enhancements but also the absence of the N170 dominance effect in the left hemisphere. Our results also demonstrated that individuals with IGD had the advantages of early automatic perception of cartoon faces and automatic detection of changes in "cartoon" features. This study enhances our understanding of the mechanism of IGD from the neurocognitive perspective and provides candidate electrophysiological indicators for the clinical diagnosis of IGD.

High Fluorescent Hyperbranched Polysiloxane Containing ß-Cyclodextrin for Cell Imaging and Drug Delivery.

Hyperbranched polysiloxane (HBPSi) is attracting increasing attention due to its intrinsic fluorescence and good biocompatibility. However, it is very challenging to explore its biological applications because of the low fluorescence intensity and quantum yield. Herein, we introduced rigid ß-cyclodextrin to the end of flexible polysiloxane chain to synthesize a novel fluorescent polymer (HBPSi-CD) and explore its biological applications. Results showed that the fluorescence intensity and quantum yield of HBPSi-CD, compared with HBPSi, were significantly enhanced. Theoretical calculations and transmission electron microscopy demonstrated that the synergy effect of intra/intermolecular hydrogen bonds and hydrophobic effect promoted the formation of large supramolecular self-assemblies and space electron delocalization systems, leading to intense fluorescence. Notably, the biocompatible HBPSi-CD not only lighted up mouse fibroblast cells, but also possessed high ibuprofen loading capacity (160 mg g-1) and superior pH-responsive drug release performance. This work promoted the development of biological applications of HBPSi.

Automatic detection advantage of problematic Internet users for Wi-Fi signal cues and the moderating effect of negative affect: An event-related potential study.

Cognitive bias toward Internet-related cues is an important factor of the formation and maintenance of the addictive behavior of problematic Internet users (PIUs). The development of fiber-optic communication and smartphones has ushered human society into the era of wireless networks. The Wi-Fi signal, the symbol of wireless network connection, represents not only network access but also a channel for communication with others anywhere at any time. Therefore, the Wi-Fi signal cues should be an effective inducer of the addictive behaviors of PIUs. We used images of Wi-Fi signal as Internet-related cues to explore the automatic detection advantage of PIUs for these cues and to determine whether negative affect, another predisposing factor for addiction, can enhance this advantage. We utilized an intergroup design in this study. The PIU and control groups each comprised 30 participants and were randomly assigned to negative or neutral affect priming group. Mismatch negativity (MMN) was induced through the deviant-standard reverse oddball paradigm. Wi-Fi signal cues and neutral cues were used as standard and deviant stimuli, respectively. Results show that the MMN induced by Wi-Fi signal cues in the PIU group was larger than that in the control group. Meanwhile, the MMN induced by Wi-Fi signal cues was considerably enhanced in the PIU group under negative affect priming relative to that in the PIU group under neutral affect priming. Overall, PIUs have an automatic detection advantage for Wi-Fi signal cues, and negative affect can enhance this advantage. Our results suggest that the MMN elicited by Wi-Fi signal cues function as a sensitive neurobiological marker tracing the change of addiction motivation for PIUs.

Specific Direction-Based Outlier Detection Approach for GNSS Vector Networks.

In this paper we propose an outlier detection approach for GNSS vector networks based on the specific direction (i.e., SD approach), along which the test statistic constructed reaches the maximum. We derive the unit vector of this specific direction in detail, and prove that the unit vector is the same as that determined by the outlier estimates in three-dimensional (3D) approach, while the distribution of the maximum test statistic in this direction is the square root of Chi-squared distribution. Therefore, eliminating an outlier along this specific direction can get the same result as that of eliminating all three components of outlier vector in 3D approach. The mathematical equivalence of SD approach and 3D approach is further demonstrated by a real GNSS network. Moreover, preliminary application of the SD approach to detect the abnormal antenna height measurement is carried out in terms of numerical simulations of multiple baseline solutions, and it shows that the SD approach can effectively detect baselines that are directly infected by corresponding receiver antenna height errors.

A two-stage filter for removing salt-and-pepper noise using noise detector based on characteristic difference parameter and adaptive directional mean filter.

In this paper, a two-stage filter for removing salt-and-pepper noise using noise detector based on characteristic difference parameter and adaptive directional mean filter is proposed. The first stage firstly detects the noise corrupted pixels by combining characteristic difference parameter and gray level extreme, then develops an improved adaptive median filter to firstly restore them. The second stage introduces a restoration scheme to further restore the noise corrupted pixels, which firstly divides them into two types and then applies different restoration skills for the pixels based on the classification result. One type of pixels is restored by the mean filter and the other type of pixels is restored by the proposed adaptive directional mean filter. The new filter firstly adaptively selects the optimal filtering window and direction template, then replaces the gray level of noise corrupted pixel by the mean value of pixels on the optimal template. Experimental results show that the proposed filter outperforms many existing main filters in terms of noise suppression and detail preservation.

Automatic detection advantage of network information among Internet addicts: behavioral and ERP evidence.

Converging evidence has proved the attentional bias of Internet addicts (IAs) on network information. However, previous studies have neither explained how characteristics of network information are detected by IAs with priority nor proved whether this advantage is in line with the unconscious and automatic process. To answer the two questions, this study aims to investigate whether IAs prioritize automatic detection of network information from the behavior and cognitive neuroscience aspects. 15 severe IAs and 15 matching healthy controls were selected using Internet Addiction Test (IAT). Dot-probe task with mask was used in the behavioral experiment, while deviant-standard reverse oddball paradigm was used in the event-related potential (ERP) experiment to induce mismatch negativity (MMN). In the dot-probe task, when the probe location appeared on the Internet-related picture's position, the IAs had significantly shorter reaction time than do the controls; in the ERP experiment, when Internet-related picture appeared, MMN was significantly induced in the IAs relative to the controls. Both experiments show that IAs can automatically detect network information.

Amino Functionalization of Reduced Graphene Oxide/Tungsten Disulfide Hybrids and Their Bismaleimide Composites with Enhanced Mechanical Properties.

A novel graphene-based nanocomposite particles (NH2-rGO/WS2), composed of reduced graphene oxide (rGO) and tungsten disulfide (WS2) grafted with active amino groups (NH2-rGO/WS2), was successfully synthesized by an effective and facile method. NH2-rGO/WS2 nanoparticles were then used to fabricate new bismaleimide (BMI) composites (NH2-rGO/WS2/BMI) via a casting method. The results demonstrated that a suitable amount of NH2-rGO/WS2 nanoparticles significantly improved the mechanical properties of the BMI resin. When the loading of NH2-rGO/WS2 was only 0.6 wt %, the impact and flexural strength of the composites increased by 91.3% and 62.6%, respectively, compared to the neat BMI resin. Rare studies have reported such tremendous enhancements on the mechanical properties of the BMI resin with trace amounts of fillers. This is attributable to the unique layered structure of NH2-rGO/WS2 nanoparticles, fine interfacial adhesion, and uniform dispersion of NH2-rGO/WS2 in the BMI resin. Besides, the thermal gravimetrical analysis (TGA) revealed that the addition of NH2-rGO/WS2 could also improve the stability of the composites.

Imidazolium Ionic Liquid Modified Graphene Oxide: As a Reinforcing Filler and Catalyst in Epoxy Resin.

Surface modification of graphene oxide (GO) is one of the most important issues to produce high performance GO/epoxy composites. In this paper, the imidazole ionic liquid (IMD-Si) was introduced onto the surface of GO sheets by a cheap and simple method, to prepare a reinforcing filler, as well as a catalyst in epoxy resin. The interlayer spacing of GO sheets was obviously increased by the intercalation of IMD-Si, which strongly facilitated the dispersibility of graphene oxide in organic solvents and epoxy matrix. The addition of 0.4 wt % imidazolium ionic liquid modified graphene oxide (IMD-Si@GO), yielded a 12% increase in flexural strength (141.3 MPa), a 26% increase in flexural modulus (4.69 GPa), and a 52% increase in impact strength (18.7 kJ/m²), compared to the neat epoxy. Additionally the IMD-Si@GO sheets could catalyze the curing reaction of epoxy resin-anhydride system significantly. Moreover, the improved thermal conductivities and thermal stabilities of epoxy composites filled with IMD-Si@GO were also demonstrated.

Seed-Assisted Growth of Single-Crystalline Patterned Graphene Domains on Hexagonal Boron Nitride by Chemical Vapor Deposition.

Vertical heterostructures based on two-dimensional layered materials, such as stacked graphene and hexagonal boron nitride (G/h-BN), have stimulated wide interest in fundamental physics, material sciences and nanoelectronics. To date, it still remains challenging to obtain high quality G/h-BN heterostructures concurrently with controlled nucleation density and thickness uniformity. In this work, with the aid of the well-defined poly(methyl methacrylate) seeds, effective control over the nucleation densities and locations of graphene domains on the predeposited h-BN monolayers was realized, leading to the formation of patterned G/h-BN arrays or continuous films. Detailed spectroscopic and morphological characterizations further confirmed that ∼85.7% of such monolayer graphene domains were of single-crystalline nature with their domain sizes predetermined throughout seed interspacing. Density functional theory calculations suggested that a self-terminated growth mechanism can be applied for the related graphene growth on h-BN/Cu. In turn, as-constructed field-effect transistor arrays based on such synthesized single-crystalline G/h-BN patterning were found to be compatible with fabricating devices with nice and steady performance, hence holding great promise for the development of next-generation graphene-based electronics.

Growing Uniform Graphene Disks and Films on Molten Glass for Heating Devices and Cell Culture.

The direct growth of uniform graphene disks and their continuous film is achieved by exploiting the molten state of glass. The use of molten glass enables highly uniform nucleation and an enhanced growth rate (tenfold) of graphene, as compared to those scenarios on commonly used insulating solids. The obtained graphene glasses show promising application potentials in daily-life scenarios such as smart heating devices and biocompatible cell-culture mediums.

Temperature-triggered chemical switching growth of in-plane and vertically stacked graphene-boron nitride heterostructures.

In-plane and vertically stacked heterostructures of graphene and hexagonal boron nitride (h-BN-G and G/h-BN, respectively) are both recent focuses of graphene research. However, targeted synthesis of either heterostructure remains a challenge. Here, via chemical vapour deposition and using benzoic acid precursor, we have achieved the selective growth of h-BN-G and G/h-BN through a temperature-triggered switching reaction. The perfect in-plane h-BN-G is characterized by scanning tunnelling microscopy (STM), showing atomically patched graphene and h-BN with typical zigzag edges. In contrast, the vertical alignment of G/h-BN is confirmed by unique lattice-mismatch-induced moiré patterns in high-resolution STM images, and two sets of aligned selected area electron diffraction spots, both suggesting a van der Waals epitaxial mechanism. The present work demonstrates the chemical designability of growth process for controlled synthesis of graphene and h-BN heterostructures. With practical scalability, high uniformity and quality, our approach will promote the development of graphene-based electronics and optoelectronics.

High-quality monolayer graphene synthesis on Pd foils via the suppression of multilayer growth at grain boundaries.

The segregation of carbon from metals in which carbon is highly soluble, such as Ni (≈1.1 atom% at 1000 °C), is a typical method for graphene growth; this method differs from the surface-catalyzed growth of graphene that occurs on other metals such as Cu (<0.04 atom%). It has not been established whether strictly monolayer graphene could be synthesized through the traditional chemical vapor deposition route on metals where carbon is highly soluble, such as Pd (≈3.5 atom%). In this work, this issue is investigated by suppressing the grain boundary segregation using a pretreatment comprising the annealing of the Pd foils; this method was motivated by the fact that the typical thick growths at the grain boundaries revealed that the grain boundary functions as the main segregation channel in polycrystalline metals. To evaluate the high crystallinity of the as-grown graphene, detailed atomic-scale characterization with scanning tunneling microscopy is performed.

Epitaxy and photoresponse of two-dimensional GaSe crystals on flexible transparent mica sheets.

We present the controlled synthesis of high-quality two-dimensional (2D) GaSe crystals on flexible transparent mica substrates via a facile van der Waals epitaxy method. Single- and few-layer GaSe nanoplates with the lateral size of up to tens of micrometers were produced. The orientation and nucleation sites of GaSe nanoplates were well-controlled. The 2D GaSe crystal-based photodetectors were demonstrated on both mechanically rigid SiO2/Si and flexible mica substrates. Efficient photoresponse was observed in 2D GaSe crystal devices on transparent flexible mica substrates, regardless of repeated bending with different radii. The controlled growth of 2D GaSe crystals with efficient photoresponsivity opens up opportunities for both fundamental aspects and new applications in photodetectors.