Super-high carrier mobilities and excellent thermoelectric performances of Tri-Tri group-VA monolayers.

High-performance thermoelectric materials in theoretical and experimental research are mostly composed of expensive, scarce, heavy elements and rarely of single light elements, which severely limit their application and development. Based on density functional and semiclassical Boltzmann transport theory, we determine that a stable phosphorene allotrope, named Tri-Tri phosphorene, has super-high electron mobility (23845.29 cm2 V-1 s-1) much higher than those of most two-dimension materials. Moreover, its optimized maximum ZT can reach up to 3.43 at room temperature (4.83 at 500 K and 5.92 at 700 K), exhibiting highly favorable prospects in practical thermoelectric systems. Motivated by the excellent properties of Tri-Tri phosphorene, we further demonstrate the structural stability of Tri-Tri arsenene and Tri-Tri antimonene and predict that the two Tri-Tri structures also have high Seebeck coefficients and electron mobilities. Their lattice thermal conductivities are dramatically decreased compared with Tri-Tri phosphorene. Thus, their predicted thermoelectric performances are also excellent, with maximum ZT values of 4.12 (Tri-Tri arsenene) and 3.54 (Tri-Tri antimonene) at room temperature. The low layer moduli of the three Tri-Tri structures indicate that they have high mechanical flexibility and suitability for current device assemblies. All these desirable properties make Tri-Tri group-VA materials promising for future applications in thermoelectric devices.

Halogen Engineering To Realize Regulable Multipolar Axes, Nonlinear Optical Response, and Piezoelectricity in Plastic Ferroelectrics.

Compared with uniaxial molecular ferroelectrics, multiaxial ferroelectrics have better application prospects because they are no longer subject to the single-crystal form and have been pursued in recent years. Halogen engineering refers to the adjustment of halogens in materials at the atomic level, which can not only explore multiaxial ferroelectrics but also help to improve piezoelectrics, recently. In this work, we successfully synthesized and characterized three multiaxial plastic ferroelectrics through the precise molecular design from I to Cl, confirming the increase of the number of polar axes of ferroelectrics from 3 to 6, the increase of second-harmonic generation density from 2.1 times to nearly 6 times of monopotassium phosphate, and the increase of piezoelectric coefficient by 140%. This systematic work has proved that halogen engineering can not only enrich the family of multiaxial plastic ferroelectrics but also promote the further development of nonlinear optical and piezoelectric materials.

Superior mechanical flexibility, lattice thermal conductivity and electron mobility of the hexagonal honeycomb carbon nitride monolayer.

Nitrogen is the nearest neighbor element of carbon and, thus, the hexagonal honeycomb carbon nitride monolayer (CxNy), which consists of a covalent network of carbon and nitrogen atoms, usually has attractive physical and chemical properties similar to those in graphene. Here, we systematically investigate the geometric structure, mechanical properties, thermal transport properties, and plasmon excitation of a new phase, labeled C3N2, and make a detailed comparison with other possible CxNy allotropes. All CxNy have a super-high layer modulus and Young's modulus. But compared with the others, C3N2 exhibits excellent mechanical flexibility, and can withstand a relatively high critical strain up to 20% (18%) along the X(Y) direction. Additionally, C3N2 also has excellent thermal and electronic transport properties, with a super-high lattice thermal conductivity of ∼110.9 W m-1 K-1 and electron mobility of ∼1617.52 cm2 V-1 s-1 at 300 K. By performing time-dependent density functional theory (TDDFT), we obtain the optical absorptions of C3N2 and C3N, and meanwhile analyze their Fourier transforms of induced charge densities at some resonant frequencies. The main optical absorption peaks of the C3N2 nanostructure are located in the ultraviolet region, and its plasmon peaks are far higher than those in C3N. Its excellent mechanical and optical properties, the larger electronic band gap, and the higher electron mobility suggest that C3N2 has great potential for application in nanoelectronics and optoelectronics.

Comparison of the performance of two depression rating scales in patients with epilepsy in southern China.

OBJECTIVE: The aim of this study was to evaluate and compare the performance of the Chinese version of the Neurological Disorder Depression Inventory for Epilepsy (CNDDI-E) with that of the depression subscale of the Hospital Anxiety and Depression Scale (C-HADS-D) as screening tools for depression in the same patients with epilepsy (PWE). METHODS: A total of 213 consecutive PWE were evaluated. Receiver operating characteristic (ROC) analysis was performed using the C-NDDI-E and C-HADS-D as predictors and the Chinese version of the Mini International Neuropsychiatric Interview (C-MINI) as the gold standard. RESULTS: The area under the curve (AUC) for the C-NDDI-E was 0.870, and the optimal cutoff score was >11 (sensitivity 85.71%, specificity 79.78%); for the C-HADS-D, the AUC was 0.804, and the optimal cutoff score was >5 (sensitivity 85.71%, specificity 62.36%). The AUC for the C-NDDI-E was larger than the AUC for the C-HADS-D, but the comparison of the AUCs revealed no significant differences (P = 0.1444). CONCLUSION: Our findings indicate that the C-NDDI-E and C-HADS-D have high validity and support the use of these screening tools for depression in PWE. Moreover, the C-NDDI-E is a better screening scale for diagnosing depression than the C-HADS-D according to the results of this study.

Reliability and validity of the Chinese version of the Patient Health Questionnaire 9 (C-PHQ-9) in patients with epilepsy.

OBJECTIVE: The aim of this study was to evaluate the clinical reliability and validity of the Chinese version of the Patient Health Questionnaire 9 (C-PHQ-9) in patients with epilepsy. METHODS: A total of 213 consecutive adult patients with epilepsy were evaluated. Receiver operating characteristic (ROC) analysis was performed using C-PHQ-9 and Chinese version of Patient Health Questionnaire 2 (C-PHQ-2) as predictors and the Mini International Neuropsychiatric Interview Plus Version 5.0.0 as the gold standard. RESULTS: The C-PHQ-9 was easily understood and quickly finished by the patients. According to the gold standard, the prevalence of current major depressive disorder in this population was 16.4%. Cronbach's α coefficient for the C-PHQ-9 was 0.860. The ROC analysis showed an area under the curve (AUC) of 0.888 (95% confidence interval [CI] = 0.838-0.927). At a cutoff score of >6, the C-PHQ-9 had a sensitivity of 82.86%, a specificity of 84.27%, a positive predictive value of 50.9%, and a negative predictive value of 96.2%. The C-PHQ-2 at a cutoff score of >1 resulted in the greatest balance of sensitivity and specificity (77.14% and 75.28%, respectively). CONCLUSION: Our findings support a high reliability and validity for the C-PHQ-9 as a screening tool for the detection of current major depression in Chinese patients with epilepsy.

Analysis of risk factors for antiepileptic drug-induced adverse psychotropic effects in Chinese outpatients with epilepsy.

Antiepileptic drugs (AEDs) have adverse psychotropic effects (APEs). To explore the risk factors for AED-induced APEs, we compared Chinese outpatients with epilepsy with and without AED-induced APEs. We reviewed the medical data of outpatients with epilepsy enrolled in the Epilepsy Long-term Follow Up Registry Study (ELFURS) between January 1, 2003 and December 31, 2015. Data on demographics, comorbidities, variables related to epilepsy, AED use, and APEs were collected. APEs were determined by experienced epileptologists based on the definition of "adverse drug reaction (ADR)" proposed by the World Health Organization (WHO) in 1972, and the causality relationship between APEs and suspected medications was assessed based on the WHO-UMC scale. APEs included effects on memory, sleep, behavior, mood, psychotic symptoms, and others in this study. We divided the study population into patients with and without AED-induced APEs and then compared the differences between the two groups using univariate and multivariate methods. A total of 3074 eligible patients were included in this study (1001 patients with AED-induced APEs and 2073 patients without AED-induced APEs). Of all APEs, the effects on memory and sleep were most pronounced. The results show that the female sex (odds ratio [OR] 1.242, 95% confidence interval [CI] 1.055-1.463), psychotic disorder comorbidities (OR 1.815, 95% CI 1.159-2.841), polytherapy with AEDs (OR 1.400, 95% CI 1.061-1.847), and the duration of epilepsy (OR 1.010, 95% CI 1.000-1.020) are significant nondrug risk factors for AED-induced APEs. Recognizing risk factors for APEs may help determine optimal treatment strategies for epilepsy.

Stacked bilayer phosphorene: strain-induced quantum spin Hall state and optical measurement.

Bilayer phosphorene attracted considerable interest, giving a potential application in nanoelectronics owing to its natural bandgap and high carrier mobility. However, very little is known regarding the possible usefulness in spintronics as a quantum spin Hall (QSH) state of material characterized by a bulk energy gap and gapless spin-filtered edge states. Here, we report a strain-induced topological phase transition from normal to QSH state in bilayer phosphorene, accompanied by band-inversion that changes number from 0 to 1, which is highly dependent on interlayer stacking. When the bottom layer is shifted by 1/2 unit-cell along zigzag/armchair direction with respect to the top layer, the maximum topological bandgap 92.5 meV is sufficiently large to realize QSH effect even at room-temperature. An optical measurement of QSH effect is therefore suggested in view of the wide optical absorption spectrum extending to far infra-red, making bilayer phosphorene a promising candidate for opto-spintronic devices.