Nano-manganese oxide and reduced graphene oxide-incorporated polyacrylonitrile fiber mats as an electrode material for capacitive deionization (CDI) technology.

Capacitive deionization (CDI) is a trending water desalination method during which the impurity ions in water can be removed by electrosorption. In this study, nano-manganese dioxide (MnO2) and reduced graphene oxide (rGO)-doped polyacrylonitrile (PAN) composite fibers are fabricated using an electrospinning technique. The incorporation of both MnO2 and rGO nanomaterials in the synthesized fibers was confirmed by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX). The electrochemical characteristics of electrode materials were examined using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and constant current charge-discharge cycles (CCCDs). The specific capacitance of the PAN electrode increased with increasing MnO2 and rGO contents as well as when thermally treated at 280 °C. Thermally treated composite fibers with 17% (w/w) MnO2 and 1% (w/w) rGO (C-rGOMnPAN) were observed to have the best electrochemical performance, with a specific capacitance of 244 F g-1 at a 10 mV s-1 scan rate. The electrode system was used to study the removal of sodium chloride (NaCl), cadmium (Cd2+) and lead (Pb2+) ions. Results indicated that NaCl showed the highest electrosorption (20 472 C g-1) compared to two heavy metal salts (14 260 C g-1 for Pb2+ and 6265 C g-1 for Cd2+), which is most likely to be due to the ease of mass transfer of lighter Na+ and Cl- ions; When compared, Pb2+ ions tend to show more electrosorption on these fibers than Cd2+ ions. Also, the C-rGOMnPAN electrode system is shown to work with 95% regeneration efficiency when 100 ppm NaCl is used as the electrolyte. Hence, it is clear that the novel binder-free, electrospun C-rGOMnPAN electrodes have the potential to be used in salt removal and also for the heavy metal removal applications of water purification.

Validation of the Sinhala version of the Repeatable Battery for Assessment of Neuropsychological Status (RBANS)

Introduction: Only the Mini mental state examination (MMSE) and Montreal Cognitive Assessment scale have been validated in a Sri Lankan population for the assessment of cognitive functions. Both tests are deficient in the number of domains assessed. Therefore validation of Repeatable Battery for Assessment of Neuropsychological Status is important as it assesses most of the cognitive domains. Objectives: To culturally adapt RBANS and investigate the validity and reliability of culturally adapted RBANS (RBANS-S). Methods: Fifty four participants with major neurocognitive disorder and 60 normal controls aged >50 were administered with RBANS-S at the Cognitive Assessment Unit, Faculty of Medicine, Colombo and National Hospital of Sri Lanka. The participants were selected after a detailed clinical assessment according to Diagnostic and Statistical Manual ­ 5 criteria. Data were analysed using SPSS data package. Results: The mean age of the sample was 69.5 years. RBANS-S total scale correlated highly with MMSE total score, (Pearson correlational coefficient = 0.793 p=0.01). Criterion validity was assessed using receiver operating curve characteristic analysis and the area under the curve was 0.937. RBANS-S showed strong concurrent validity us indicated by its significant correlations with the MMSE. All of the RBANS-S subtests demonstrated significant correlations with the MMSE subsets. The sensitivity and specificity for RBANS-S was 89% and 85% respectively at a totals score of 80.5. The RBANS-S yielded a reliability coefficient of 0.929. Conclusions: Culturally adapted RBANS-S is a valid and reliable instrument which can be used in assessment of cognitive functions.

Four-qubit entanglement classification from string theory.

We invoke the black-hole-qubit correspondence to derive the classification of four-qubit entanglement. The U-duality orbits resulting from timelike reduction of string theory from D=4 to D=3 yield 31 entanglement families, which reduce to nine up to permutation of the four qubits.

Wrapped branes as qubits.

Recent work has established a correspondence between the tripartite entanglement measure of three qubits and the macroscopic entropy of the four-dimensional 8-charge STU black hole of supergravity. Here we consider the configurations of intersecting D3-branes, whose wrapping around the six compact dimensions T6 provides the microscopic string-theoretic interpretation of the charges, and associate the three-qubit basis vectors |ABC>, (A, B, C=0 or 1) with the corresponding 8 wrapping cycles. In particular, we relate a well-known fact of quantum information theory, that the most general real three-qubit state can be parameterized by four real numbers and an angle, to a well-known fact of string theory, that the most general STU black hole can be described by four D3-branes intersecting at an angle.