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Gallium nitride based light emitting diodes have shown their advantages in the application of visible light communication (VLC) besides general illumination. However, the modulation bandwidth of current commercial GaN based LEDs still cannot meet daily application of VLC. It has been reported that the modulation bandwidth can be enhanced by the surface plasmon due to the coupling between the surface plasmon and the active region of LEDs. However, the light output may be decreased. In this study, we designed a GaN-based surface plasmon LEDs using lateral coupling to both increase the light output and the modulation bandwidth. The finite difference time domain method was utilized to investigate the modulation bandwidth of the GaN-based surface plasmon LEDs as well as the light output. Simulation results show that the modulation bandwidth was estimated to be ~2.3 GHz with 2.5 times enhancement of the light output compared with conventional LED structure. This design of surface plasmon LEDs will be useful for applications in high frequency visible light communication. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine the effectiveness of microwave pretreatments on methane production from two switchgrass tissues (leaf vs. stem). The methane production from the leaf fraction was significantly affected by the microwave final temperature, while production from the stem fraction was affected by the combination of the microwave final temperature and heating rate. Thus, the highest methane yield from the leaf (134.81 mL CH4/g of volatile solids (VS)) was obtained at 100 °C, while the highest yield from the stem (99.35 mL CH4/g VS) was obtained at 150 °C, with a heating rate of 10 °C/min. Although methane production from the leaf fraction was merely enhanced by 9.1% after microwave pretreatments, the time required to reach 80% of ultimate methane production was reduced by 12 days. For the stem fraction, methane production was improved by 5.2% after microwave pretreatment, and the time to obtain 80% of ultimate methane production increased. [ABSTRACT FROM AUTHOR]

In gene therapy, how genetic therapeutics can be efficiently and safely delivered into target tissues/cells remains a major obstacle to overcome. To address this issue, nanoparticles consisting of non-covalently coupled polyethyleneimine (PEI) and folic acid (FA) to the magnetic and fluorescent core/shell of Fe3O4@ SiO2(FITC) was tested for their ability to deliver Notch-1 shRNA. Our results showed that Fe3O4@ SiO2(FITC)/PEI-FA/Notch-1 shRNA nanoparticles are 64 nm in diameter with well dispersed and superparamagnetic. These nanoparticles with on significant cytotoxicity are capable of delivering Notch-1 shRNA into human breast cancer MDA-MB-231 cells with high efficiency while effectively protected shRNA from degradation by exogenous DNaseI and nucleases. Magnetic resonance (MR) imaging and fluorescence microscopy showed significant preferential uptake of Fe3O4@SiO2(FITC)/PEI-FA/Notch-1 shRNA nanocomplex by MDA-MB-231 cells. Transfected MDA-MB-231 cells exhibited significantly decreased expression of Notch-1, inhibited cell proliferation, and increased cell apoptosis, leading to the killing of MDA-MB-231 cells. In light of the magnetic targeting capabilities of Fe3O4@SiO2(FITC)/PEI-FA, our results show that by complexing with a second molecular targeting therapeutic, such as Notch-1 shRNA in this report, Fe3O4@SiO2(FITC)/PEI-FA can be exploited as a novel, non-viral, and concurrent targeting delivery system for targeted gene therapy as well as for MR imaging in cancer diagnosis. [ABSTRACT FROM AUTHOR]

Switchgrass is a perennial C4 plant with great potential as a bioenergy source and, thus, a high demand for establishment from seed. This research investigated the effects of ultrasound treatment on germination and seedling growth in switchgrass. Using an orthogonal matrix design, conditions for the ultrasound pretreatment in switchgrass seed, including sonication time (factor A), sonication temperature (factor B) and ultrasound output power (factor C), were optimized for germinating and stimulating seedling growth (indicated as plumular and radicular lengths) through modeling analysis. The results indicate that sonication temperature (B) was the most effective factor for germination, whereas output power (C) had the largest effect on seedling growth when ultrasound treatment was used. Combined with the analyses of range, variance and models, the final optimal ultrasonic treatment conditions were sonication for 22.5 min at 39.7°C and at an output power of 348 W, which provided the greatest germination percentage and best seedling growth. For this study, the orthogonal matrix design was an efficient method for optimizing the conditions of ultrasound seed treatment on switchgrass. The electrical conductivity of seed leachates in three experimental groups (control, soaked in water only, and ultrasound treatment) was determined to investigate the effects of ultrasound on seeds and eliminate the effect of water in the ultrasound treatments. The results showed that the electrical conductivity of seed leachates during either ultrasound treatment or water bath treatment was significantly higher than that of the control, and that the ultrasound treatment had positive effects on switchgrass seeds. [ABSTRACT FROM AUTHOR]

Alllelopathic potential of chicory was investigated by evaluating its effect on seed germination, soluble sugar, malondialdehyde (MDA) and the chlorophyll content of three target plants species (Festuca arundinacea, Trifolium repens and Medicago sativa). The secretion of allelochemicals was regulated by keeping the donor plant (chicory) separate from the three target plant species and using different pH and nitrogen levels. Leachates from donor pots with different pH levels and nitrogen concentrations continuously irrigated the target pots containing the seedlings. The allelopathic effects of the chicory at equivalent coupling of nitrogen supply and pH level on the three target plants species were explored via models analyses. The results suggested a positive effect of nitrogen supply and pH level on allelochemical secretion from chicory plants. The nitrogen supply and pH level were located at a rectangular area defined by 149 to 168 mg/l nitrogen supply combining 4.95 to 7.0 pH value and point located at nitrogen supply 177 mg/l, pH 6.33 when they were in equivalent coupling effects; whereas the inhibitory effects of equivalent coupling nitrogen supply and pH level were located at rectangular area defined by 125 to 131 mg/l nitrogen supply combining 6.71 to 6.88 pH value and two points respectively located at nitrogen supply 180 mg/l with pH 6.38 and nitrogen supply 166 mg/l with pH 7.59. Aqueous extracts of chicory fleshy roots and leaves accompanied by treatment at different sand pH values and nitrogen concentrations influenced germination, seedling growth, soluble sugar, MDA and chlorophyll of F. arundinacea, T. repens and M. sativa. Additionally, we determined the phenolics contents of root and leaf aqueous extracts, which were 0.104% and 0.044% on average, respectively. [ABSTRACT FROM AUTHOR]

Background: The new ruthenium(II)-arene complex, which bearing a carborane unit, ruthenium and ferrocenyl functional groups, has a novel versatile synthetic chemistry and unique properties of the respective material at the nanoscale level. The ruthenium(II)-arene complex shows significant cytotoxicity to cancer cells and tumor-inhibiting properties. However, ruthenium(II)-arene complex of mechanism of anticancer activity are scarcely explored. Therefore, it is necessary to explore ruthenium(II)-arene complex mechanism of anticancer activity for application in this area. Results: In this study, the ruthenium(II)-arene complex could significantly induce apoptosis in human lung cancer HCC827 cell line. At the concentration range of 5 μM-100 μM, ruthenium(II)-arene complex had obvious cell cytotoxicity effect on HCC827 cells with IC50 values ranging 19.6 ± 5.3 μM. Additionally, our observations demonstrate that the ruthenium(II)-arene complex can readily induce apoptosis in HCC827 cells, as evidenced by Annexin-V-FITC, nuclear fragmentation as well as DNA fragmentation. Treatment of HCC827 cells with the ruthenium(II)-arene complex resulted in dose-dependent cell apoptosis as indicated by high cleaved Caspase-8,9 ratio. Besides ruthenium(II)-arene complex caused a rapid induction of cleaved Caspase-3 activity and stimulated proteolytic cleavage of poly-(ADP-ribose) polymerase (PARP) in vitro and in vivo. Conclusion: In this study, the ruthenium(II)-arene complex could significantly induce apoptosis in human lung cancer HCC827 cell line. Treatment of HCC827 cells with the ruthenium(II)-arene complex resulted in dose-dependent cell apoptosis as indicated by high cleaved Caspase-8,9 ratio. Besides ruthenium(II)-arene complex caused a rapid induction of cleaved Caspase-3 activity and stimulated proteolytic cleavage of poly-(ADP-ribose) polymerase (PARP) in vitro and in vivo. Our results suggest that ruthenium(II)-arene complex could be a candidate for further evaluation as a chemotherapeutic agent for human cancers, especially lung cancer. [ABSTRACT FROM AUTHOR]

In this contribution, we have prepared and explored a novel nano-interface based probe for the rapid identification and highly sensitive detection of cancer cells by means of an electrochemical study. The new probe tetrathiafulvalene (TTF) carboxylate salt (TTF-(COONBu4)2, ditetrabutylammonium salt for propylenedithio-4′,5′-tetrathiafulvalene-4,5-dicarboxylate), which has specific spectral and electrochemical properties, has been synthesized and assembled with carbon nanotubes to form a new type of nanocomposite. A simple method of fabricating the β-CD/MWCNT modified electrodes based on functionalized multi-walled carbon nanotubes (MWCNTs) and β-cyclodextrin (β-CD) has been explored by using glassy carbon electrodes (GCEs), which could remarkably enhance the sensitivity of the biomolecular detection. Our results demonstrate that the combination of the new probe TTF-(COONBu4)2with β-CD/MWCNT modified electrodes could be readily utilized to sensitively detect cancer cells such as liver cancer cells SMMC-7721 and HepG2, drug sensitive leukemia K562/B.W cells and drug resistant leukemia K562/ADM cells, with a detection limit of ∼103cells mL−1. This may provide a novel strategy for the potential and promising application of the new TTF molecular probe in the development of multi-signal responsive biosensors for the early diagnosis of cancers. [ABSTRACT FROM AUTHOR]

The application of quantum dots (QDs) in various biomedical areas requires detailed studies of their toxicity. We report a new strategy for probing the biocompatibility of these nanocrystals, namely, a dynamic investigation of cellular uptake images, cell growth curves, metabolic activity changes, and apoptosis aspects of cadmium telluride QDs capped with cysteamine (Cys-CdTe QDs) on human hepatocellular carcinoma SMMC-7721 cells. We used a real-time cell electronic sensing (RT-CES) system in combination with fluorescence microscopy, 3-(4,5-dimethyl-thiazol-zyl)-2,5-diphenyltetrazolium bromide assay, and flow cytometry (FCM) analysis. As observed from fluorescence images and RT-CES system results, Cys-CdTe QDs can readily bind on the cell plasma membrane and then enter into the cancer cell, causing decreased adherence of cancer cells during the initial 6−12 h, while the metabolic activity apparently decreased. After 24 h, the metabolic activity of the cancer cells was significantly reduced, with continued reduction in metabolic activity observed at even longer incubation times. Moreover, FCM observation and DNA fragmentation analysis clearly indicate apoptosis-related phenomena when SMMC-7721 cells were treated with the Cys-CdTe QDs. Thus, our study reveals details of the cellular aging and death process induced by Cys-CdTe QDs. [ABSTRACT FROM AUTHOR]

Successful placement of cervical pedicle screws requires accurate identification of both entry point and trajectory. However, literature has not provided consistent recommendations regarding the direction of pedicle screw insertion and entry point location. The objective of this study was to define a guideline regarding the optimal entry point and trajectory in placing subaxial cervical pedicle screws and to evaluate the screw accuracy in cadaver cervical spines. The guideline for entry point and trajectory for each vertebra was established based on the recently published morphometric data. Six fresh frozen cervical spines (C3–C7) were used. There were two men and four women. After posterior exposure, the entry point was determined and the cortical bone of the entry point was removed using a 2-mm burr. Pilot holes were created with a cervical probe based on the guideline using fluoroscopy. After tapping, 3.5-mm screws with appropriate length were inserted. After screw insertion, every vertebra was dissected and inspected for pedicle breach. The pedicle width, height, pedicle transverse angulation and actual screw insertion angle were measured. A total of 60 pedicle screws were inserted. No statistical difference in pedicle width and height was found between the left and right sides for each level. The overall accuracy of pedicle screws was 83.3%. The remaining 13.3% screws had noncritical breach, and 3.3% had critical breach. The critical breach was not caused by the guideline. There was no statistical difference between the pedicle transverse angulation and the actual screw trajectory created using the guideline. There was statistical difference in pedicle width between the breach and non-breach screws. In conclusion, high success rate of subaxial cervical pedicle screw placement can be achieved using the recently proposed operative guideline and oblique views of fluoroscopy. However, careful preoperative planning and good surgical skills are still required to ensure screw placement accuracy and to reduce the risk of neural and vascular injury. [ABSTRACT FROM AUTHOR]

Pedicle screws are placed using pilot holes. The trajectory of pilot holes can be verified by pedicle sounding or radiographs. However, a pilot hole alone does not insure that the screw will follow the pilot hole. No studies have characterized the risk of misalignment of a pedicle screw with respect to its pilot hole trajectory. The objective of this study was to measure the misalignment angles between pedicle screws and pilot holes with or without tapping. Six human cadaveric thoracic spines were used. One hundred and forty pilot holes were created with a straight probe. Steel wires were temporarily inserted and their positions were recorded with CT scans. The left pedicles were tapped with 4.5 mm fluted tap and the right pedicles remained untapped. Pedicle screws (5.5 mm) were inserted into the tapped and untapped pedicles followed by CT scans. The trajectories of pilot holes and screws were calculated using three-dimensional vector analysis. A total of 133 pilot holes (95%) were inside pedicles. For the untapped side, 14 out of 68 (20%) screws did not follow the pilot holes and were outside the pedicles. For the tapped side, 2 out of 65 (3%) did not follow and breached the pedicles. The average misalignment angles between the screw and pilot hole trajectory were 7.7° ± 6.5° and 5.6° ± 3.2° for the untapped side and tapped side, respectively ( P < 0.05). Most pedicle screws had lateral screw breach (13 out of 16) whereas most pilot holes had medial pedicle breach (6 out of 7). Tapping of pilot holes (1 mm undertap) helps align pedicle screws and reduces the risk of screw malposition. Although most pedicle screws had lateral breach, the risk of medial pedicle breach of the pilot holes must be recognized. [ABSTRACT FROM AUTHOR]

The effect of functionalized nickel (Ni) nanoparticles capped with positively charged tetraheptylammonium on cellular uptake of drug quercetin into hepatocellular carcinoma cells (SMMC-7721) has been explored in this study via microscopy and electrochemical characterization as well as MTT assay. Meanwhile, the influence of Ni nanoparticles and/or quercetin on cell proliferation has been further evaluated by the real-time cell electronic sensing (RT-CES) study. Our observations indicate that Ni nanoparticles could efficiently improve the permeability of cancer cell membrane, and remarkably enhance the accumulation of quercetin in SMMC-7721 cells, suggesting that Ni nanoparticles and quercetin would facilitate the synergistic effect on inhibiting proliferation of cancer cells. [ABSTRACT FROM AUTHOR]

Single level axial lumbar interbody fusion (AxiaLIF) using a transsacral rod through a paracoccygeal approach has been developed with promising early clinical results and biomechanical stability. Recently, the transsacral rod has been extended to perform a two-level fusion at both L4–L5 and L5–S1 levels (AxiaLIF II). No biomechanical studies have been conducted on multilevel fusion using the AxiaLIF technique. In this study, the biomechanics of L4–S1 motion segments instrumented with the AxiaLIF II transsacral rod was evaluated. Six human cadaveric lumbosacral spine segments from L4 to S1 were used (age ranges 46–74 years). Unconstrained and non-destructive pure moments in axial torsion, lateral bending, and flexion extension were applied to each specimen following intact, standalone AxiaLIF II, and AxiaLIF II with two posterior fixation options: facet screws and pedicle screws with rods. Range of motion was calculated from the raw data collected with an optical motion tracking system. The two-level transsacral rod was successfully inserted in all the specimens. At L4–L5 level in axial torsion (AT) and flexion extension (FE), none of the surgical treatments showed statistically significant difference between the procedures (all P > 0.05) although facet screws and pedicle screws had higher stability on average. In lateral bending (LB), the two posterior fixation techniques had significantly higher construct stability ( P < 0.05) than the standalone rod. No significant difference was found between facet screws and pedicle screws ( P = 0.821). At L5–S1 level in AT and LB, none of the surgical treatments were found to be statistically significant (all P > 0.05). In FE, standalone two-level transsacral rod had significantly higher range of motion (ROM) compared with the posterior fixation techniques ( P < 0.05). In conclusion, the standalone rod reduced intact ROM significantly. Supplementary fixations including facet screws and pedicle screws are required to achieve higher construct stability for successful fusion. Further clinical studies are essential to evaluate the practical success of this technique. [ABSTRACT FROM AUTHOR]

The article presents a semi-empirical model of mixed-mode sub-critical crack propagation for orthotropic polymers subjected to continuous loading. A combination of opening and shearing propagation modes are considered by the model. Crack propagation in an orthotropic liquid crystalline polymer film for orientation angles of 45 and 90 degrees are measured optically to provide empirical constants. Comparison of predicted and measured crack propagation at 30, 60, and 75 degrees is used to validate the model. Identification of a critical angle at which the crack propagation rates for the opening and shearing modes are equivalent are presented.

The article presents a study that evaluates the revision strategies for failed cervical lateral mass screw fixation. It compares the pullout strength of a revision screw in the same trajectory, a Roy-Camille trajectory and pedicle screw fixation. Furthermore, it analyzes the contributions of bone mineral density (BMD) and peak insertional torque to pullout strength. Results showed no significant difference noted in insertional torque or pullout between Magerl and Roy-Camille revision groups.

The article compares the biomechanics of two revision iliac screws on human cadaveric pelves. It attempts to determine if a bigger screw resists loosening under cyclic loading better than a longer screw in revising loosened iliac screws. The study shows that iliac screws are susceptible to loosening under cyclic loading due to the cancellous bone structure surrounding the screw body.

The article explores a study highlighting the macroscopic failure of multilayered viscoelastic polymers. It seeks to characterize and define creep in laminated loaded in the linear viscoelastic region. Results have strengthened the claims on the validity of the analytical model for laminates created from nylon66 and liquid crystalline polymer films. They have also shown that the validated macroscale failure models have the ability to qualify a variety of materials. An overview of the impact of layer properties and orientation on overall laminate performance is offered.

Three kinds of magnetic nanoparticle, tetraheptylammonium capped nanoparticles ofFe3O4,Fe2O3 and Ni have been synthesized, and the synergistic effect of these nanoparticles onthe drug accumulation of the anticancer drug daunorubicin in leukaemia cellshas been explored. Our observations indicate that the enhancement effect ofFe3O4 nanoparticles is muchstronger than that of Fe2O3 and Ni nanoparticles, suggesting that nanoparticle surface chemistry and size as well asthe unique properties of the magnetic nanoparticles themselves may contributeto the synergistic enhanced effect of the drug uptake of targeted cancer cells. [ABSTRACT FROM AUTHOR]

Eco-friendly ceramic capacitors gradually become an important section of pulsed power devices. However, the synchronous realization of ultra-high energy storage density (Wrec > 6 J/cm³) and efficiency (η > 90%) is difficult. Thus, a novel multiscale amelioration strategy in Na0.5Bi0.5TiO3-based ceramics is proposed to achieve ultra-high energy storage density and efficiency. The multiscale amelioration strategy for (Na0.5Bi0.47La0.03)0.94Ba0.06TiO3 (NBLBT) ceramic focuses on grain size, bandgap width, and dielectric relaxor behavior, which can be regulated by introducing Sr(Al0.5Nb0.25Ta0.25)O3 (SANT). On the one hand, the refined grain size and increased bandgap width are conducive to improving the breakdown strength. On the other hand, the optimized dielectric relaxation behavior is beneficial to suppress the remanent polarization. Accordingly, an ultrahigh Wrec = 6.89 J/cm³ and η = 90.1% are simultaneously achieved in 0.84NBLBT- 0.16SANT ceramic. In addition, the sample synchronously possesses excellent thermal and frequency stability (a variation within 5% in Wrec and η), transient discharge rate of t0.9 ~ 78.8 ns and a high-power density of PD ~ 114.5 MW/cm³. This study provides an effective strategy to further develop pulsed power devices. [ABSTRACT FROM AUTHOR]

A biaxially wave-shaped polydimethylsiloxane (PDMS) surface was developed simply by using a taro leaf as the template. The resulting leaf-templated PDMS (L-PDMS) possesses a micro-sized curved interface structure, which is greatly beneficial for the exact embedding of a silver nanowire (AgNW) network conductive film covering the L-PDMS surface. The intrinsically curved AgNW/L-PDMS film surface, without any dangling nanowire, could prevent the fracture of AgNWs due to stretching stress even after cyclic stretching. More importantly, it also exhibited a biaxial stretchability, which showed ultra-stable resistance after continuous stretching for 100 cycles each in X- and Y-directions. This biaxially stretchable AgNW/L-PDMS film could extend the application fields in stretchable electronics. [ABSTRACT FROM AUTHOR]