LiMn2O4/CNTs and LiNi0.5Mn1.5O4/CNTs Nanocomposites as High-Performance Cathode Materials for Lithium-Ion Batteries

The demand of higher energy density and higher power capacity of lithium(Li)-ion secondary batteries has led to the search for electrode materials whose capacities and performance are better than those available today. Carbon nanotubes(CNTs), with their unique properties such as 1D tubular structure, high electrical and thermal conductivities, and extremely large surface area, have been used as materials to prepare cathodes for Li-ion batteries. The structure and morphology of CNTs were analyzed by X-ray diffraction(XRD), scanning electron microscopy(SEM), and transmission electron microscopy(TEM). The functional groups on the purified CNT surface such as –COOH, –OH were characterized by Fourier Transform infrared spectroscopy. The electrode materials were fabricated from LiMn2O4(LMO), doped spinel LiNi0.5Mn1.5O4, and purified CNTs via solid-state reaction. The structure and morphology of the electrode were characterized using XRD, SEM, and TEM. Finally, the efficiency of the electrode materials using CNTs was evaluated by cyclic voltammetry and electrochemical impedance spectroscopy.     

Optimizing flurbiprofen-loaded NLC by central composite factorial design for ocular delivery

The purpose of this study was to design and optimize a new topical delivery system for ocular administration of flurbiprofen (FB), based on lipid nanoparticles. These particles, called nanostructured lipid carriers (NLC), were composed of a fatty acid (stearic acid (SA)) as the solid lipid and a mixture of Miglyol(?) 812 and castor oil (CO) as the liquid lipids, prepared by the hot high pressure homogenization method. After selecting the critical variables influencing the physicochemical characteristics of the NLC (the liquid lipid (i.e. oil) concentration with respect to the total lipid (cOil/L (wt%)), the surfactant and the flurbiprofen concentration, on particle size, polydispersity index and encapsulation efficiency), a three-factor five-level central rotatable composite design was employed to plan and perform the experiments. Morphological examination, crystallinity and stability studies were also performed to accomplish the optimization study. The results showed that increasing cOil/L (wt%) was followed by an enhanced tendency to produce smaller particles, but the liquid to solid lipid proportion should not exceed 30 wt% due to destabilization problems. Therefore, a 70:30 ratio of SA to oil (miglyol + CO) was selected to develop an optimal NLC formulation. The smaller particles obtained when increasing surfactant concentration led to the selection of 3.2 wt% of Tween(?) 80 (non-ionic surfactant). The positive effect of the increase in FB concentration on the encapsulation efficiency (EE) and its total solubilization in the lipid matrix led to the selection of 0.25 wt% of FB in the formulation. The optimal NLC showed an appropriate average size for ophthalmic administration (228.3 nm) with a narrow size distribution (0.156), negatively charged surface (-33.3 mV) and high EE (～90%). The in vitro experiments proved that sustained release FB was achieved using NLC as drug carriers. Optimal NLC formulation did not show toxicity on ocular tissues.     

Equalization Based Receivers for Wideband MIMO/BLAST Systems

This paper focuses on the usage of Equalization-Based receivers for Wideband Code-Division Multiple Access (WCDMA) Multiple Input, Multiple Output (MIMO) Bell Labs Layered Space Time (BLAST)-type systems. The main receivers on trial are the Zero-Forcing and Minimum Mean Square Error (MMSE) algorithm-based receivers and their variants, employing Parallel interference cancellation (PIC) and Iterative Partial Cancellation (IPC) schemes. To assess its performance in an existing system, the uncoded Universal Mobile Telecommunications System (UMTS) High-Speed Downlink Packet Access (HSDPA) standard was considered (using solely QPSK modulation) alongside the reference UMTS environments. The BER performance is assessed both by simulation and by semi-analytical processing.     

Laparoscopic Toupet fundoplication for gastroesophageal reflux disease with poor esophageal body motility

Impaired esophageal body motility is a complication of chronic gastroesophageal reflux disease (GERD). In patients with this disease, a 360-degree fundoplication may result in severe postoperative dysphagia. Forty-six patients with GERD who had a weak lower esophageal sphincter pressure and a positive acid reflux score associated with impaired esophageal body peristalsis in the distal esophagus (amplitude <30 mm Hg and >10% simultaneous or interrupted waves) were selected to undergo laparoscopic Toupet fundoplication. They were compared with 16 similar patients with poor esophageal body function who underwent Nissen fundoplication. The patients who underwent Toupet fundoplication had less dysphagia than those who had the Nissen procedure (9% vs.44%; P=0.0041). Twenty-four-hour ambulatory pH monitoring and esophageal manometry were repeated in 31 Toupet patients 6 months after surgery. Percentage of time of esophageal exposure to pH <4.0, DeMeester reflux score, lower esophageal pressure, intra-abdominal length, vector volume, and distal esophageal amplitude all improved significantly after surgery. Ninety-one percent of patients were free of reflux symptoms. The laparoscopic Toupet fundoplication provides an effective antireflux barrier according to manometric, pH, and symptom criteria. It avoids potential postoperative dysphagia in patients with weak esophageal peristalsis and results in improved esophageal body function 6 months after surgery.     

Effects of Storage Humidity on the Mechanical, Microstructural, and Drug Release Properties of Hydroxypropylmethylcellulose-Based Hydrophilic Matrix Tablets

The effects of storage humidity on the properties of hydroxypropylmethylcellulose (HPMc)-based hydrophilic matrix tablets were investigated. Hydrochlorothiazide tablets prepared with HPMCs of different thickening capacities were stored for 6 months (a) at a relative humidity corresponding to the prestorage equilibrium moisture content of the HPMCs, or (b) at a higher relative humidity. Only tablets stored at the higher humidity showed significant changes in properties, indicating that the observed changes (reduced crushing strength, increased total porosity, and increased mean pore diameter) were due to water uptake. All changes were completed within 1 month of storage. Drug release properties were unaffected, even after 6 months. Effectively identical results were obtained regardless of whether the HPMC variety used had a nominal viscosity of 4,000 cP or 100,000 cP.     

Design and simulation of high-performance lateral bipolar junction transistor on partial buried oxide

In this work, we propose a new structure of a lateral bipolar junction transistor (LAT-BJT) on partial buried oxide (PBOX). The novelty of the proposed LAT-BJT device is the use of PBOX, covering just base and emitter regions only. A two-dimensional (2D) calibrated simulation study of the proposed LAT-BJT device has shown that the proposed LAT-BJT on PBOX’s performance is unique when the PBOX is just covering base and emitter regions. At this length of PBOX, a sharp enhancement in cut-off frequency (f_T) (~10 times higher) is achieved in the proposed LAT-BJT on PBOX in comparison to an LAT-BJT on silicon-on-insulator (SOI). The breakdown voltage of the proposed LAT-BJT on PBOX is double than that of the LAT-BJT on SOI device at this PBOX length. A notable enhancement in current gain (β) is observed in the proposed LAT-BJT on PBOX in comparison to the LAT-BJT on bulk device. To check the performance of the proposed LAT-BJT on PBOX at the circuit level, two inverters have been designed and simulated using the mixed-mode simulations of Atlas simulator. It has been observed that the proposed LAT-BJT on PBOX significantly outperforms the conventional LAT-BJT device in switching performance. A notable improvement of 32% in ON delay and 72.9% in OFF delay is obtained in the proposed LAT-BJT on PBOX device in comparison to the conventional LAT-BJT device.     

Scanning electrochemical microscopy for the investigation of localized degradation processes in coated metals: Effect of oxygen

The effect of oxygen content on the corrosion reactions inside a holiday in a polymer-coated metal substrate was studied by SECM without adding a redox mediator. The system was mild steel coated by polyurethane in KCl. By selecting different values for the potential applied to the ultramicroelectrode tip, local concentrations of species involved in the degradation process are monitored, namely Fe(II) ions, hydrogen peroxide and oxygen. The results show a variation in both the shape and the magnitude of the scan lines measured over the holiday. A critical oxygen concentration was found below which the corrosion reaction is not observed.     

Pharmacological Evaluation and Preliminary Pharmacokinetics Studies of a New Diclofenac Prodrug without Gastric Ulceration Effect

Long-term nonsteroidal anti-inflammatory drugs (NSAIDs) therapy has been associated with several adverse effects such as gastric ulceration and cardiovascular events. Among the molecular modifications strategies, the prodrug approach is a useful tool to discover new safe NSAIDs. The 1-(2,6-dichlorophenyl)indolin-2-one is a diclofenac prodrug which demonstrated relevant anti-inflammatory properties without gastro ulceration effect. In addition, the prodrug decreases PGE₂ levels, COX-2 expression and cellular influx into peritoneal cavity induced by carrageenan treatment. Preliminary pharmacokinetic studies have shown in vivo bioconversion of prodrug to diclofenac. This prodrug is a new nonulcerogenic NSAID useful to treat inflammatory events by long-term therapy.     

Aquatic photochemistry of isoflavone phytoestrogens: degradation kinetics and pathways

Isoflavones are plant-derived chemicals that are potential endocrine disruptors. Although some recent studies have detected isoflavones in natural waters, little is known about their aquatic fates. The photochemical behaviors of the isoflavones daidzein, formononetin, biochanin A, genistein, and equol were studied under simulated solar light and natural sunlight. All of these phytoestrogens were found to be photolabile under certain conditions. Daidzein and formononetin degraded primarily by direct photolysis. Their expected near-surface summer half-lives in pH 7 water at 47° latitude are expected to be 10 and 4.6 h, respectively. Biochanin A, genistein, and equol degraded relatively slowly by direct photolysis at environmentally realistic pH values, though they showed significant degradation rate enhancements in the presence of natural organic matter (NOM). The indirect photolysis rates for these compounds scaled with NOM concentration, and NOM from microbial origin was found to be a more potent photosensitizer than NOM from terrestrial sources. Mechanistic studies were performed to determine the indirect photolysis pathways responsible for the rate enhancements. Results of these studies implicate reaction with both singlet oxygen and excited state triplet NOM. Environmental half-lives for biochanin A, genistein, and equol are expected to vary on the basis of pH as well as NOM source and concentration.