Single-crystalline hole-transporting layers for efficient and stable organic light-emitting devices.

Efficient charge-carrier injection and transport in organic light-emitting devices (OLEDs) are essential to simultaneously achieving their high efficiency and long-term stability. However, the charge-transporting layers (CTLs) deposited by various vapor or solution processes are usually in amorphous forms, and their low charge-carrier mobilities, defect-induced high trap densities and inhomogeneous thickness with rough surface morphologies have been obstacles towards high-performance devices. Here, organic single-crystalline (SC) films were employed as the hole-transporting layers (HTLs) instead of the conventional amorphous films to fabricate highly efficient and stable OLEDs. The high-mobility and ultrasmooth morphology of the SC-HTLs facilitate superior interfacial characteristics of both HTL/electrode and HTL/emissive layer interfaces, resulting in a high Haacke's figure of merit (FoM) of the ultrathin top electrode and low series-resistance joule-heat loss ratio of the SC-OLEDs. Moreover, the thick and compact SC-HTL can function as a barrier layer against moisture and oxygen permeation. As a result, the SC-OLEDs show much improved efficiency and stability compared to the OLEDs based on amorphous or polycrystalline HTLs, suggesting a new strategy to developing advanced OLEDs with high efficiency and high stability.

Interaction between catechol-O-methyltransferase Val/Met polymorphism and cognitive reserve for negative symptoms in schizophrenia.

BACKGROUND: Cognitive reserve (CR) and the catechol-O-methyltransferase (COMT) Val/Met polymorphism are reportedly linked to negative symptoms in schizophrenia. However, the regulatory effect of the COMT genotype on the relationship between CR and negative symptoms is still unexamined. AIM: To investigate whether the relationship between CR and negative symptoms could be regulated by the COMT Val/Met polymorphism. METHODS: In a cross-sectional study, 54 clinically stable patients with schizophrenia underwent assessments for the COMT genotype, CR, and negative symptoms. CR was estimated using scores in the information and similarities subtests of a short form of the Chinese version of the Wechsler Adult Intelligence Scale. RESULTS: COMT Met-carriers exhibited fewer negative symptoms than Val homozygotes. In the total sample, significant negative correlations were found between negative symptoms and information, similarities. Associations between information, similarities and negative symptoms were observed in Val homozygotes only, with information and similarities showing interaction effects with the COMT genotype in relation to negative symptoms (information, ß = -0.282, 95%CI: -0.552 to -0.011, P = 0.042; similarities, ß = -0.250, 95%CI: -0.495 to -0.004, P = 0.046). CONCLUSION: This study provides initial evidence that the association between negative symptoms and CR is under the regulation of the COMT genotype in schizophrenia.

Resistive Memory Devices at the Thinnest Limit: Progress and Challenges.

The Si-based integrated circuits industry has been developing for more than half a century, by focusing on the scaling-down of transistor. However, the miniaturization of transistors will soon reach its physical limits, thereby requiring novel material and device technologies. Resistive memory is a promising candidate for in-memory computing and energy-efficient synaptic devices that can satisfy the computational demands of the future applications. However, poor cycle-to-cycle and device-to-device uniformities hinder its mass production. 2D materials, as a new type of semiconductor, is successfully employed in various micro/nanoelectronic devices and have the potential to drive future innovation in resistive memory technology. This review evaluates the potential of using the thinnest advanced materials, that is, monolayer 2D materials, for memristor or memtransistor applications, including resistive switching behavior and atomic mechanism, high-frequency device performances, and in-memory computing/neuromorphic computing applications. The scaling-down advantages of promising monolayer 2D materials including graphene, transition metal dichalcogenides, and hexagonal boron nitride are presented. Finally, the technical challenges of these atomic devices for practical applications are elaborately discussed. The study of monolayer-2D-material-based resistive memory is expected to play a positive role in the exploration of beyond-Si electronic technologies.

Suppressing Structural Relaxation in Nanoscale Antimony to Enable Ultralow-Drift Phase-Change Memory Applications.

Phase-change random-access memory (PCRAM) devices suffer from pronounced resistance drift originating from considerable structural relaxation of phase-change materials (PCMs), which hinders current developments of high-capacity memory and high-parallelism computing that both need reliable multibit programming. This work realizes that compositional simplification and geometrical miniaturization of traditional GeSbTe-like PCMs are feasible routes to suppress relaxation. While to date, the aging mechanisms of the simplest PCM, Sb, at nanoscale, have not yet been unveiled. Here, this work demonstrates that in an optimal thickness of only 4 nm, the thin Sb film can enable a precise multilevel programming with ultralow resistance drift coefficients, in a regime of ≈10-4 -10-3 . This advancement is mainly owed to the slightly changed Peierls distortion in Sb and the less-distorted octahedral-like atomic configurations across the Sb/SiO2 interfaces. This work highlights a new indispensable approach, interfacial regulation of nanoscale PCMs, for pursuing ultimately reliable resistance control in aggressively-miniaturized PCRAM devices, to boost the storage and computing efficiencies substantially.

EMDR versus waiting list in individuals at clinical high risk for psychosis with post-traumatic stress symptoms: A randomized controlled trial.

BACKGROUND: Post-traumatic stress disorder (PTSD) is highly prevalent in the individuals at clinical-high risk for psychosis (CHR). The aim of this study was to examine the efficacy and safety of Eye Movement Desensitization and Reprocessing (EMDR) in individuals at CHR with comorbid PTSD or subthreshold PTSD in a randomized controlled trial. METHODS: Fifty-seven individuals at CHR with PTSD or subthreshold PTSD formed the study sample. The eligible participants were randomly assigned to a 12 weeks EMDR treatment (N = 28) or a waiting list condition (WL, N = 29). The structured interview for psychosis risk syndrome (SIPS), the clinician administered post-traumatic stress disorder scale (CAPS) and a battery of self-rating inventories covering depressive, anxiety and suicidal symptoms were administered. RESULTS: Twenty-six participants in the EMDR group and all the participants in the WL group completed the study. The analyses of covariance revealed greater reduction of the mean scores on CAPS (F = 23.2, Partial η2 = 0.3, P < 0.001), SIPS positive scales (F = 17.8, Partial η2 = 0.25, P < 0.001) and all the self-rating inventories in the EMDR group than in the WL group. Participants in the EMDR group were more likely to achieve remission of CHR compared to those in the WL group at endpoint (60.7 % vs. 31 %, P = 0.025). CONCLUSIONS: EMDR treatment not only effectively improved traumatic symptoms, but also significantly reduced the attenuated psychotic symptoms and resulted in a higher remission rate of CHR. This study highlighted the necessity of adding a trauma-focused component to the present approach of early intervention in psychosis.

Recent advances of bioactive proteins/polypeptides in the treatment of breast cancer.

Proteins do not only serve as nutrients to fulfill the demand for food, but also are used as a source of bioactive proteins/polypeptides for regulating physical functions and promoting physical health. Female breast cancer has the highest incidence in the world and is a serious threat to women's health. Bioactive proteins/polypeptides exert strong anti-tumor effects and exhibit inhibition of multiple breast cancer cells. This review discussed the suppressing effects of bioactive proteins/polypeptides on breast cancer in vitro and in vivo, and their mechanisms of migration and invasion inhibition, apoptosis induction, and cell cycle arrest. This may contribute to providing a basis for the development of bioactive proteins/polypeptides for the treatment of breast cancer.

Resistive switching mechanism of MoS2based atomristor.

The non-volatile resistive switching process of a MoS2based atomristor with a vertical structure is investigated by first-principles calculations. It is found that the monolayer MoS2with a S vacancy defect (VS) could maintain an insulation characteristic and a high resistance state (HRS) is remained. As an electrode metal atom is adsorbed on the MoS2monolayer, the semi-conductive filament is formed with the assistance ofVS. Under this condition, the atomristor presents a low resistance state (LRS). The ON state current of this semi-filament is increased close to two orders of magnitude larger than that without the filament. The energy barrier for an Au-atom to penetrate the monolayer MoS2viaVSis as high as 6.991 eV. When it comes to a double S vacancy (VS2), the energy barrier is still amounted to 3.554 eV, which manifests the bridge-like full conductive filament cannot form in monolayer MoS2based atomristor. The investigation here promotes the atomic level understanding of the resistive switching properties about the monolayer MoS2based memristor. The physics behind should also work in atomristors based on other monolayer transition-metal dichalcogenides, like WSe2and MoTe2. The investigation will be a reference for atomristor-device design or optimization.

Electronic state evolution of oxygen-doped monolayer WSe2 assisted by femtosecond laser irradiation.

Electronic states are significantly correlated with chemical compositions, and the information related to these factors is especially crucial for the manipulation of the properties of matter. However, this key information is usually verified by after-validation methods, which could not be obtained during material processing, for example, in the field of femtosecond laser direct writing inside materials. Here, critical evolution stages of electronic states for monolayer tungsten diselenide (WSe2) around the modification threshold (at a Mott density of ∼1013 cm-2) are observed by broadband femtosecond transient absorption spectroscopy, which is associated with the intense femtosecond-laser-assisted oxygen-doping mechanism. First-principles calculations and control experiments on graphene-covered monolayer WSe2 further confirm this modification mechanism. Our findings reveal a photochemical reaction for monolayer WSe2 under the Mott density condition and provide an electronic state criterion to in situ monitor the degrees of modification in monolayer transition metal dichalcogenides during the femtosecond laser modification.

Recent Progress in Double-Layer Honeycomb Structure: A New Type of Two-Dimensional Material.

Two-dimensional (2D) materials are no doubt the most widely studied nanomaterials in the past decade. Most recently, a new type of 2D material named the double-layer honeycomb (DLHC) structure opened a door to achieving a series of 2D materials from traditional semiconductors. However, as a newly developed material, there still lacks a timely understanding of its structure, property, applications, and underlying mechanisms. In this review, we discuss the structural stability and experimental validation of this 2D material, and systematically summarize the properties and applications including the electronic structures, topological properties, optical properties, defect engineering, and heterojunctions. It was concluded that the DLHC can be a universal configuration applying to III-V, II-VI, and I-VII semiconductors. Moreover, these DLHC materials indeed have exotic properties such as being excitonic/topological insulators. The successful fabrication of DLHC materials further demonstrates it is a promising topic. Finally, we summarize several issues to be addressed in the future, including further experimental validation, defect engineering, heterojunction engineering, and strain engineering. We hope this review can help the community to better understand the DLHC materials timely and inspire their applications in the future.

Convergent and divergent gray matter volume abnormalities in unaffected first-degree relatives and ultra-high risk individuals of schizophrenia.

High-risk populations of schizophrenia can be mainly identified as genetic high-risk based on putative endophenotypes or ultra-high-risk (UHR) based on clinically manifested symptoms. Previous studies have consistently shown brain structural abnormalities in both genetic high-risk and UHR individuals. In this study, we aimed to disentangle the convergent and divergent pattern of gray matter alterations between UHR and unaffected first-degree relatives from genetic high-risk individuals. We used structural MRI scans and voxel-based morphometry method to examine gray matter volume (GMV) differences among 23 UHR subjects meeting the Structured Interview for Prodromal Syndromes (SIPS) criteria, 18 unaffected first-degree relatives (UFDR), 26 first-episode schizophrenia patients (FES) and 54 healthy controls (CN). We found that a number of brain regions exhibited a monotonically decreasing trend of GMV from CN to UFDR to UHR to FES. Compared with CN, the UHR subjects showed significant decreases of GMV similar to the patients in the inferior temporal gyrus, fusiform gyrus, middle occipital gyrus, insula, and limbic regions. Moreover, the UHR transformed subgroup had significantly lower GMV than UHR non-transformed subgroup in the right inferior temporal/fusiform gyrus. On the other hand, the UFDR subjects only showed significant GMV decreases in the inferior temporal gyrus and fusiform. Moreover, we found GMV in the occipital lobe was negatively correlated with the UHR subjects' composite positive symptom of SIPS, and GMV in the cerebellum was positively correlated with FES subjects' symptom severity. Our results suggest that GMV deficits and regional dysfunction are evident prior to the onset of psychosis and are more prominent in the UHR than the UFDR individuals.

Spin-Valley Depolarization in van der Waals Heterostructures.

The appearance of van der Waals heterostructures offers a new solution to valleytronics. Here, we observe the spin-valley depolarization process of electrons and holes in type-II MoS2-WSe2 heterostructures simultaneously for the first time by valley-resolved broad-band femtosecond pump-probe experiments. The different depolarization paths between electrons and holes make them have different spin-valley polarization lifetimes. The spin-valley depolarization pathway of holes is mainly dominated by a phonon-assisted intervalley scattering process, while intra- and intervalley coupling can trigger additional depolarization pathways for electrons. The hole polarization lifetime can be further prolonged to more than three times in trilayer heterostructure 2MoS2-WSe2. For MoS2-WS2 that has strong orbital hybridization of Mo and W atoms, both electrons and holes lose the spin-valley polarization extremely soon after charge separation, behaving similarly to intraexcitons in a monolayer. Our work advances the basic understanding of spin-valley depolarization of van der Waals heterostructures and facilitates the effort toward longer lifetime valleytronic devices for information transfer and storage applications.

The effects of childhood trauma on personality in unaffected first-degree relatives of patients with major depressive disorder.

ABSTRAC: OBJECTIVES: This study aimed to preliminarily and exploratorily examine the associations between childhood trauma (CT), its subtypes, and personality traits among unaffected first-degree relatives (FDR, children, or siblings) of patients with major depressive disorder (MDD). METHODS: The study sample included three subgroups: MDD patients (N = 85), Patients' FDRs (N = 35), and healthy control individuals (HC, N = 89). The Childhood Trauma Questionnaire (CTQ) was used to assess childhood trauma and the Eysenck Personality Questionnaire was used to assess personality traits. RESULTS: Significant differences were found in a few personality traits (p < 0.05 for extraversion, neuroticism, and psychoticism) among MDD patients, FDR, and HC, and there were no significant differences between HC and FDR. In the FDR group, compared with those without CT, participants with CT scored significantly higher for neuroticism (N) (F = 3.246, p = 0.046). CT was significantly associated with N, psychoticism (P) and Lie (L), and the strongest association was between CT total score and N. Significantly positive correlations were found between N and sexual abuse (SA) (r = 0.344, p = 0.043), emotional neglect (EN) (r = 0.394, p = 0.019), physical neglect (PN) (r = 0.393, p = 0.019), and CTQ total score (r = 0.452, p = 0.006); between P and CTQ total score (r = 0.336, p = 0.049); and significant negative correlations were found between L and EN (r = -0.446, p = 0.007), CTQ total score (r = -0.375, p = 0.027). CONCLUSION: In unaffected FDRs, there were significant associations between childhood trauma and a few personality traits, including neuroticism, psychoticism, and lie, and emotional neglect was significantly associated with neuroticism.

Modulation Doping: A Strategy for 2D Materials Electronics.

It remains a remarkable challenge to develop practical techniques for controllable and nondestructive doping in two-dimensional (2D) materials for their use in electronics and optoelectronics. Here, we propose a modulation doping strategy, wherein the perfect n-/p-type channel layer is achieved by accepting/donating electrons from/to the defects inside an adjacent encapsulation layer. We demonstrate this strategy in the heterostructures of BN/graphene, BN/MoS2, where the previously believed useless deep defects, such as the nitrogen vacancy in BN, can provide free carriers to the graphene and MoS2. The carrier density is further modulated by engineering the surroundings of the encapsulation layer. Moreover, the defects and carriers are naturally separated in space, eliminating the effects of Coulomb impurity scattering and thus allowing high mobility in the 2D limit. This doping strategy provides a highly viable route to tune 2D channel materials without inducing any structural damage, paving the way for high-performance 2D nanoelectronic devices.

Phase-Change-Memory Process at the Limit: A Proposal for Utilizing Monolayer Sb2Te3.

One central task of developing nonvolatile phase change memory (PCM) is to improve its scalability for high-density data integration. In this work, by first-principles molecular dynamics, to date the thinnest PCM material possible (0.8 nm), namely, a monolayer Sb2Te3, is proposed. Importantly, its SET (crystallization) process is a fast one-step transition from amorphous to hexagonal phase without the usual intermediate cubic phase. An increased spatial localization of electrons due to geometrical confinement is found to be beneficial for keeping the data nonvolatile in the amorphous phase at the 2D limit. The substrate and superstrate can be utilized to control the phase change behavior: e.g., with passivated SiO2 (001) surfaces or hexagonal Boron Nitride, the monolayer Sb2Te3 can reach SET recrystallization in 0.54 ns or even as fast as 0.12 ns, but with unpassivated SiO2 (001), this would not be possible. Besides, working with small volume PCM materials is also a natural way to lower power consumption. Therefore, the proposed PCM working process at the 2D limit will be an important potential strategy of scaling the current PCM materials for ultrahigh-density data storage.

Metallic Graphene Nanoribbons.

Isolated graphene nanoribbons (GNRs) usually have energy gaps, which scale with their widths, owing to the lateral quantum confinement effect of GNRs. The absence of metallic GNRs limits their applications in device interconnects or being one-dimensional physics platform to research amazing properties based on metallicity. A recent study published in Science provided a novel method to produce metallic GNRs by inserting a symmetric superlattice into other semiconductive GNRs. This finding will broader the applications of GNRs both in nanoelectronics and fundamental science.

The Neglect of Left-Behind Children in China: A Meta-Analysis.

OBJECTIVE: To evaluate the neglect of left-behind children (LBC) in China. METHOD: Participants: Children separated from one or both parents for at least 6 months. Intervention: Trauma of separation. Comparison: Non-left-behind children (NLBC). Outcomes: Neglect rates and severity. Only case-control studies were included. RESULTS: Thirteen studies were included; there were 18,688 LBC in a large sample (N = 42,003) of children aged 0-18 years in China. The overall neglect rate was significantly higher in LBC compared to NLBC (odds ratio [OR] = 1.58, 95% confidence interval [CI] = [1.50, 1.67], p < .01) based on the Chinese Rural Child Neglected Evaluation Model (CRCNEM) and the Parents-Child Conflict Tactics Scales (OR = 1.44, 95% CI [1.35, 1.54], p < .01). The overall neglect severity in LBC was also significantly higher than NLBC (SMD = 0.31, 95% CI [0.28, 0.33], p < .01). The same trends were observed in sex subgroups. With regard to subtypes, LBC were significantly more likely to have emotional neglect (OR = 2.29, 95% CI [1.88, 2.78], p < .01), medical neglect (OR = 1.79, 95% CI [1.62, 1.98], p < .01), physical neglect (OR = 1.75, 95% CI [1.60, 1.91], p < .01), security neglect (OR = 1.52, 95% CI [1.32, 1.75], p < .01), educational neglect (OR = 1.50, 95% CI [1.31, 1.72], p < .01), and social neglect (OR = 1.33, 95% CI [1.18, 1.51], p < .01). Furthermore, LBC had significantly higher severity in medical neglect (SMD = 0.31, 95% CI [0.27, 0.35], p < .01), emotional neglect (SMD = 0.28, 95% CI [0.24, 0.32], p < .01), physical neglect (SMD = 0.24, 95% CI [0.18, 0.29], p < .01), security neglect (SMD = 0.26, 95% CI [0.23, 0.29], p < .01), educational neglect (SMD = 0.25, 95% CI [0.20, 0.31], p < .01), and social neglect (SMD = 0.25, 95% CI [0.10, 0.40], p < .01). CONCLUSION: The neglect rates and severity in LBC in China were both significantly higher than those in NLBC. There was a strong association between neglect and LBC. Public policy changes are urgently needed to improve the dire situation and the well-being of the LBC.

The effect of increased family finance and dual-parental absence since infancy on Children's cognitive Abilities.

Existing research suggests that parental absence per se does not have a main effect on children's cognitive development. However, this body of research is confounded by decreased family finance resulted from parental absence. Further insights on children's cognitive development can be gained by studying situations where parental absence actually leads to higher family finance. China's rural left-behind children (LBC) are uniquely suited for this purpose because of their extended separation from parents who migrated to work for better family finance. The participants were 74 LBC (M = 9.99 years, SD = 2.66) whose parents both migrated away for work within six months of their births and 74 non-left-behind children (NLBC) (M = 10.03 years, SD = 2.58) of similar backgrounds but whose parents never migrated. We used the 4th Edition of the Wechsler Intelligence Scale for Children (WISC-IV) to individually collected data on the children's Verbal Comprehension (which includes Similarities, Vocabulary, and Comprehension subtests), Perceptual Reasoning (which includes Block Design, Picture Concepts and Matric Reasoning subtests), Working Memory (which includes Digit Span and Letter-Number Sequencing subtests), and Processing Speed (which includes Coding and Symbol Search subtests). We found that the LBC scored lower than the NLBC on the language Comprehension and Vocabulary subtests of the Verbal Comprehension Index (Cohen's d = 0.41; p = .01). Subsequent General Linear Modeling analyses revealed that for the Comprehension subtest: (1) dual-parental absence significantly and negatively predicted Comprehension scores and (2) monthly family income significantly and positively predicted Comprehension scores for the LBC but not for the NLBC. For Vocabulary subtest, only dual-parental absence was significant. Overall, these results offer a deeper understanding on the effect of dual parental absence and changes in family finance on different domains of children's cognitive development.

The attenuated visual scanpaths of patients with schizophrenia whilst recognizing emotional facial expressions are worsened in natural social scenes.

Alteration of visual scanpaths under emotional facial expression in schizophrenia patients has been described in recent years; however, it is not clear whether such results are different when they transfer to faces in natural social scenes. The present study was designed to investigate the effects of emotional faces in natural social scenes on the gaze patterns of patients with schizophrenia, compared to gaze at isolated faces. A novel theme identification task was used where participants selected a positive, neutral or negative word to describe an emotional picture. Participants were 29 patients with schizophrenia and 31 healthy controls. The Positive and Negative Syndrome Scale (PANSS) and the Scale of Social Function in Psychosis Inpatients (SSPI) were used to assess symptoms and social functioning. In total, patients with schizophrenia showed significantly fewer fixations, saccades numbers and decreased fixations in areas of interest. As expected, patients showed shorter scanpath length, but only in the pictures with social settings. Furthermore, the effect size of scanpaths parameters under social scene was all greater than isolated face. In addition, patients compared to controls showed more abnormal scanpath parameters processing negative and neutral faces than positive faces, especially in social scene. The present study suggests that scanpath length for social scene faces may be more sensitive than for isolated face pictures. Our findings further support restricted scanpath whilst recognizing emotional facial expressions in natural social scenes as a favorable topic for further investigation as a trait marker.

Adjunctive Reboxetine for Schizophrenia: Meta-analysis of Randomized Double-blind, Placebo-controlled Trials.

BACKGROUND: Results of previous studies on the safety and efficacy of adjunctive reboxetine for schizophrenia have been inconsistent. AIM: The aim of this study was to examine the efficacy and tolerability of reboxetine as an adjunct medication to antipsychotic treatment in a meta-analysis of randomized controlled trials (RCTs). METHODS: Two independent investigators extracted data for a random effects meta-analysis and assessed the quality of studies using risk of bias and the Jadad scale. Weighted and standardized mean differences (WMDs/SMDs) and risk ratio (RR)±95% confidence intervals (CIs) were calculated. RESULTS: Nine RCTs (n=630) with double-blind design were identified. Reboxetine outperformed placebo in improving negative (9 RCTs, n=602, SMD: -0.47 [95% CI: -0.87, -0.07], p=0.02; I2=82%), but not the overall, positive, and general psychopathology scores. The significant therapeutic effect on negative symptoms disappeared in the sensitivity analysis after removing an outlying study and in 50% (6/12) of the subgroup analyses. Reboxetine outperformed placebo in reducing weight (3 RCTs, n=186, WMD: -3.83 kg, p=0.04; I2=92%) and body mass index (WMD: -2.23 kg/m2, p=0.04; I2=95%). Reboxetine caused dry mouth but was associated with less weight gain overall and weight gain of ≥7% of the initial weight. All-cause discontinuation and other adverse events were similar between reboxetine and placebo. CONCLUSION: Adjunctive reboxetine could be useful for attenuating antipsychotic-induced weight gain, but it was not effective in treating psychopathology including negative symptoms in schizophrenia.