Self-activated ‘green’ carbon nanoparticles for symmetric solid-state supercapacitors

Tuning of porosity and surface properties of nanoparticles especially on carbon-based nanomaterials, adopting a ‘greener’ or self-activation synthesis technique for electrical charge storage, is progressing. Herein, we report the self-activation of Teak wood sawdust in a nitrogen atmosphere at different activation temperatures to synthesize carbon nanoparticles. The activated carbon nanoparticles synthesized at 900 °C exhibits a maximum?~?360 m² g^?1 surface area with?~?2 nm average pore size diameter. Five electrolytes viz. KOH, KCl, Na₂SO₄, NaCl, and H₃PO₄ are used for studying the supercapacitance nature of the activated carbon nanoparticles in a 3-electrode configuration. A maximum specific capacitance of?~?208 F g^?1 @ 0.25 A g^?1 is obtained in 1 M KOH as the electrolyte. Two symmetric supercapacitors, aqueous (1 M KOH) and solid-state (PVA/KOH), are fabricated, and their performance difference is compiled. The solid-state symmetric supercapacitor performs in a wider voltage window (1.7 V) with a superior energy density of 27.1 Wh kg^?1 at a power density of 178 W kg^?1.

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Effect of Rare-Earth Additives on Electromechanical Properties of Modified Lead Titanate Ceramics

The influence of rare-earth additives, such as La, Nd, Sm, and Gd, and poling conditions on the electromechanical properties of (Pb_{1−3 x /2}Ln _x )(Ti_0.98Mn_0.02)O₃ compositions, x = 0.04–0.12, were investigated. The type and amount of additive were found to affect the lattice anisotropy, dielectric constant, and electromechanical properties. A large electromechanical anisotropy ( k _t / k _p ) could be obtained in 10 mol% Sm-modified and 8 mol% Gd-modified lead titanate ceramics, and seemed to correlate to a low Poisson's ratio.     

Low temperature hydrothermal synthesis of monodispersed flower-like titanate nanosheets

Monodispersed flower-like titanate superstructure was successfully prepared by simple hydrothermal process without any surfactant or template. N₂-sorption analysis, scanning electron microscopy (SEM), and X-ray diffraction (XRD) observation of as-synthesized product revealed the formation of flower-like titanate with diameter of about 250–450 nm and BET surface area (S_BET) of 350.7 m² g^?1. Upon thermal treatment at 500 °C, the titanate nanosheets were converted into anatase TiO₂ with moderate deformation of their structures. The as-prepared flower-like titanate showed high photocatalytic activity for H₂ evolution from water splitting reaction. Moreover, the sample heat treated at 500 °C exhibited higher photocatalytic activity than that of commercial TiO₂ anatase powder (ST-01).     

The effects of multimodal feedback on older adults' task performance given varying levels of computer experience

This experiment examines the effect that computer experience and various combinations of feedback (auditory, haptic, and/or visual) have on the performance of older adults completing a drag-and-drop task on a computer. Participants were divided into three computer experience groups, based on their frequency of use and breadth of computer knowledge. Each participant completed a series of drag-and-drop tasks under each of seven feedback conditions (three unimodal, three bimodal, one trimodal). Performance was assessed using measures of efficiency and accuracy. Experienced users responded well to all multimodal feedback while users without experience responded well to auditory-haptic bimodal, but poorly to haptic-visual bimodal feedback. Based on performance benefits for older adults seen in this experiment, future research should extend investigations to effectively integrate multimodal feedback into GUI interfaces in order to improve usability for this growing and diverse user group.     

One-Pot Synthesis of Coumarin–Indomethacin Hybrids as COX-2 Targeting Probes for Cancer Imaging

Facile synthesis of 6- or 7-substituted coumarin-indomathacin hybrids (Coum-IDM) has been developed for specific cyclooxygenase-2 (COX-2) binding along with their intrinsic fluorescent properties. A mild and rapid condensation/dehydrative cyclization of 2-hydroxy benzaldehyde with activated indomethacin was carried out in one step under ultrasound irradiation. Coum-IDM₄ was found to be the best of this series as it presented significant binding to COX-2 and exhibited higher fluorescent intensity in cancer cells than in normal cells. Therefore, in the light of drug development tools, this new hybrid system could be a potential targeted probe for COX-2-overexpressed inflammation and cancer-cell tracking.     

On investigation of vibro-acoustics of FDB spindle motors for hard disk drives

The present work investigates vibro-acoustic behaviors of the fluid dynamic bearing (FDB) spindle motors for hard disk drives (HDD) through the sound spectra and the frequency response functions (FRF) of the motor structure. The quantitative evidence on the significance of the acoustic noise originated from the electromagnetic source is deduced from the sound spectra that were measured in two distinct cases of the spinning motor: in the normal operation and at the moment immediately after the power supply was disconnected. It is found that the effect of electromagnetic noise source is more dominant than the combined effect of the mechanical and aerodynamic sources. In addition, it is identified that, within the audible range of frequency, the frequency range of 13.4–20 kHz deems important to the noise problem as it is the main contributor to the acoustic noise for the FDB spindle motors. Moreover, the structural resonances that can be identified via the FRF are found to play an important role in the noise emitted by the motors. The concurrence of resonance and excitation frequencies clearly intensifies the sound spectrum, resulting in high discrete peaks, hence higher decibel level.     

Evolution of antioxidant compounds in lime residues during drying

This work aimed at studying the effects of pretreatment, namely, hot water blanching, and hot air-drying (60–120 °C) on the evolutions of vitamin C, phenolic compounds, nomilin and limonin, which are potential bioactive compounds in lime residues during drying. Blanching was found to decrease both the antioxidant contents and activities of the residues due to thermal degradation and loss with the blanched water. During drying, nomilin and limonin contents first increased, probably due to the remaining enzyme activity after blanching. After this period, the amounts of both nomilin and limonin dropped rapidly, due to thermal degradation. Product temperature was found to be a major factor controlling the changes of limonoids and there was no direct correlation between the moisture change during drying and limonoid contents. During degradation of vitamin C and phenolic compounds, the amounts of both substances decreased as the product temperature increased and the moisture content decreased during drying. The amount of phenolic compounds correlated well with the total antioxidant activity and phenolic compounds were found to be a major contributor to antioxidant activity of the product.     

Biomarkers for Refractory Lupus Nephritis: A Microarray Study of Kidney Tissue

The prognosis of severe lupus nephritis (LN) is very different among individual patients. None of the current biomarkers can be used to predict the development of refractory LN. Because kidney histology is the gold standard for diagnosing LN, the authors hypothesize that molecular signatures detected in kidney biopsy tissue may have predictive value in determining the therapeutic response. Sixty-seven patients with biopsy-proven severely active LN by International Society of Nephrology/Renal Pathology Society (ISN/RPS) classification III/IV were recruited. Twenty-three kidney tissue samples were used for RNA microarray analysis, while the remaining 44 samples were used for validation by real-time polymerase chain reaction (PCR) gene expression analysis. From hundreds of differential gene expressions in refractory LN, 12 candidates were selected for validation based on gene expression levels as well as relevant functions. The candidate biomarkers were members of the innate immune response molecules, adhesion molecules, calcium-binding receptors, and paracellular tight junction proteins. S100A8, ANXA13, CLDN19 and FAM46B were identified as the best kidney biomarkers for refractory LN, and COL8A1 was identified as the best marker for early loss of kidney function. These new molecular markers can be used to predict refractory LN and may eventually lead to novel molecular targets for therapy.