Effect of the Flame Retardants and Glass Fiber on the Polyamide 66/Polyphenylene Oxide Composites.

In this work, polyamide 66/polyphenylene oxide (PA66/PPO) composites, including the flame retardants 98 wt% aluminum diethylphosphinate + 2 wt% polydimethylsiloxane (P@Si), Al(OH)3-coated red phosphorus (RP*), and glass fiber (GF), were systematically studied, respectively. The limiting oxygen index (LOI), UL-94 vertical burning level, and thermal and mechanical properties of the PA66/PPO composites were characterized. The results showed that the P@Si and RP flame retardants both improved the LOI value and UL-94 vertical burning level of the PA66/PPO composites, and PA66/PPO composites passed to the UL-94 V-0 level when the contents of P@Si and RP* flame retardants were 16 wt% and 8 wt%. On the other hand, the mechanical properties of the PA66/PPO composites were reduced from a ductile to a brittle fracture mode. The addition of GF effectively made up for these defects and improved the mechanical properties of the PA66/PPO composites containing the P@Si and RP*, but it did not change the fracture mode. P@Si and RP* flame retardants improved the thermal decomposition of PA66/PPO/GF composites and reduced the maximum mass loss rates, showing that the PA66/PPO/GF composites containing the P@Si and RP* flame retardants could be used in higher-temperature fields.

An integrated high-throughput microfluidic circulatory fluorescence-activated cell sorting system (µ-CFACS) for the enrichment of rare cells.

There is an increasing need for the enrichment of rare cells in the clinical environments of precision medicine, personalized medicine, and regenerative medicine. With the possibility of becoming the next-generation cell sorters, microfluidic fluorescence-activated cell sorting (µ-FACS) devices have been developed to avoid cross-contamination, minimize device footprint, and eliminate bio-aerosols. However, due to highly precise flow control, the achievable throughput of the µ-FACS system is generally lower than the throughput of conventional FACS devices. Here, we report a fully integrated high-throughput microfluidic circulatory fluorescence-activated cell sorting (µ-CFACS) system for the enrichment of clinical rare cells. A microfluidic sorting cartridge has been developed for enriching samples through a sequential sorting process, which was further realized by the integration of both fast amplified piezoelectrically actuated on-chip valves and compact pneumatic cylinders actuated on-chip valves. At an equivalent throughput of ∼8000 events per second (eps), the purity of rare fluorescent microparticles has been significantly increased from ∼0.01% to ∼27.97%. An enrichment of ∼9400-fold from 0.009% to 81.86% has also been demonstrated for isolating fluorescently labelled MCF-7 breast cancer cells from Jurkat cells at an equivalent sorting throughput of ∼6400 eps. With the advantages of high throughput and contamination-free design, the proposed integrated µ-CFACS system provides a new option for the enrichment of clinical rare cells.

Amplified piezoelectrically actuated on-chip flow switching for a rapid and stable microfluidic fluorescence activated cell sorter.

With the potential to avoid cross-contamination, eliminate bio-aerosols, and minimize device footprints, microfluidic fluorescence-activated cell sorting (µ-FACS) devices could become the platform for the next generation cell sorter. Here, we report an on-chip flow switching based µ-FACS mechanism with piezoelectric actuation as a fast and robust sorting solution. A microfluidic chip with bifurcate configuration and displacement amplified piezoelectric microvalves has been developed to build the µ-FACS system. Rare fluorescent microparticles of different sizes have been significantly enriched from a purity of ∼0.5% to more than 90%. An enrichment of 150-fold from ∼0.6% to ∼91% has also been confirmed for fluorescently labeled MCF-7 breast cancer cells from Jurkat cells, while viability after sorting was maintained. Taking advantage of its simple structure, low cost, fast response, and reliable flow regulation, the proposed µ-FACS system delivers a new option that can meet the requirements of sorting performance, target selectivity, device lifetime, and cost-effectiveness of implementation.

Identification of Early-Stage Alzheimer's Disease Using Sulcal Morphology and Other Common Neuroimaging Indices.

Identifying Alzheimer's disease (AD) at its early stage is of major interest in AD research. Previous studies have suggested that abnormalities in regional sulcal width and global sulcal index (g-SI) are characteristics of patients with early-stage AD. In this study, we investigated sulcal width and three other common neuroimaging morphological measures (cortical thickness, cortical volume, and subcortical volume) to identify early-stage AD. These measures were evaluated in 150 participants, including 75 normal controls (NC) and 75 patients with early-stage AD. The global sulcal index (g-SI) and the width of five individual sulci (the superior frontal, intra-parietal, superior temporal, central, and Sylvian fissure) were extracted from 3D T1-weighted images. The discriminative performances of the other three traditional neuroimaging morphological measures were also examined. Information Gain (IG) was used to select a subset of features to provide significant information for separating NC and early-stage AD subjects. Based on the four modalities of the individual measures, i.e., sulcal measures, cortical thickness, cortical volume, subcortical volume, and combinations of these individual measures, three types of classifiers (Naïve Bayes, Logistic Regression and Support Vector Machine) were applied to compare the classification performances. We observed that sulcal measures were either superior than or equal to the other measures used for classification. Specifically, the g-SI and the width of the Sylvian fissure were two of the most sensitive sulcal measures and could be useful neuroanatomical markers for detecting early-stage AD. There were no significant differences between the three classifiers that we tested when using the same neuroanatomical features.

Unipolar memristive switching in bulk negative temperature coefficient thermosensitive ceramics.

A memristive phenomenon was observed in macroscopic bulk negative temperature coefficient nickel monoxide (NiO) ceramic material. Current-voltage characteristics of memristors, pinched hysteretic loops were systematically observed in the Ag/NiO/Ag cell. A thermistor-based model for materials with negative temperature coefficient was proposed to explain the mechanism of the experimental phenomena. Most importantly, the results demonstrate the potential for a realization of memristive systems based on macroscopic bulk materials.

Nanostructured Li2S-C composites as cathode material for high-energy lithium/sulfur batteries.

With a theoretical capacity of 1166 mA·h·g(-1), lithium sulfide (Li(2)S) has received much attention as a promising cathode material for high specific energy lithium/sulfur cells. However, the insulating nature of Li(2)S prevents the achievement of high utilization (or high capacity) and good rate capability. Various efforts have been made to ameliorate this problem by improving the contact between Li(2)S and electronic conductors. In the literature, however, a relatively high capacity was only obtained with the Li(2)S content below 50 wt %; therefore, the estimated cell specific energy values are often below 350 W·h·kg(-1), which is insufficient to meet the ever-increasing requirements of newly emerging technologies. Here, we report a cost-effective way of preparing nanostructured Li(2)S-carbon composite cathodes by high-energy dry ball milling of commercially available micrometer-sized Li(2)S powder together with carbon additives. A simple but effective electrochemical activation process was used to dramatically improve the utilization and reversibility of the Li(2)S-C electrodes, which was confirmed by cyclic voltammetry and electrochemical impedance spectroscopy. We further improved the cycling stability of the Li(2)S-C electrodes by adding multiwalled carbon nanotubes to the nanocomposites. With a very high specific capacity of 1144 mA·h·g(-1) (98% of the theoretical value) obtained at a high Li(2)S content (67.5 wt %), the estimated specific energy of our cell was ∼610 W·h·kg(-1), which is the highest demonstrated so far for the Li/Li(2)S cells. The cells also maintained good rate capability and improved cycle life. With further improvement in capacity retention, nanostructured Li(2)S-C composite cathodes may offer a significant opportunity for the development of rechargeable cells with a much higher specific energy.