Evaluating inhibition conditions in high-solids anaerobic digestion of organic fraction of municipal solid waste.

PubMed

Schievano, Andrea; D'Imporzano, Giuliana; Malagutti, Luca; Fragali, Emilio; Ruboni, Gabriella; Adani, Fabrizio

2010-07-01

High-solids anaerobic digestion (HSAD) processes, when applied to different types of organic fractions of municipal solid waste (OFMSW), may easily be subjected to inhibition due to organic overloading. In this study, a new approach for predicting these phenomena was proposed based on the estimation of the putrescibility (oxygen consumption in 20 h biodegradation, OD(20)) of the organic mixtures undergoing the HSAD process. Different wastes exhibiting different putrescibility were subjected to lab-scale batch-HSAD. Measuring the organic loading (OL) as volatile solids (VS) was found unsuitable for predicting overload inhibition, because similar VS contents corresponded to both inhibited and successful trials. Instead, the OL calculated as OD(20) was a very good indicator of the inhibiting conditions (inhibition started for OD(20)>17-18 g O(2)kg(-1)). This new method of predicting inhibition in the HSAD process of diverse OFMSW may be useful for developing a correct approach to the technology in very different contexts. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Strontium hydroxyapatite/chitosan nanohybrid scaffolds with enhanced osteoinductivity for bone tissue engineering.

PubMed

Lei, Yong; Xu, Zhengliang; Ke, Qinfei; Yin, Wenjing; Chen, Yixuan; Zhang, Changqing; Guo, Yaping

2017-03-01

For the clinical application of bone tissue engineering with the combination of biomaterials and mesenchymal stem cells (MSCs), bone scaffolds should possess excellent biocompatibility and osteoinductivity to accelerate the repair of bone defects. Herein, strontium hydroxyapatite [SrHAP, Ca 10-x Sr x (PO 4 ) 6 (OH) 2 ]/chitosan (CS) nanohybrid scaffolds were fabricated by a freeze-drying method. The SrHAP nanocrystals with the different x values of 0, 1, 5 and 10 are abbreviated to HAP, Sr1HAP, Sr5HAP and Sr10HAP, respectively. With increasing x values from 0 to 10, the crystal cell volumes and axial lengths of SrHAP become gradually large because of the greater ion radius of Sr 2+ than Ca 2+ , while the crystal sizes of SrHAP decrease from 70.4nm to 46.7nm. The SrHAP/CS nanohybrid scaffolds exhibits three-dimensional (3D) interconnected macropores with pore sizes of 100-400μm, and the SrHAP nanocrystals are uniformly dispersed within the scaffolds. In vitro cell experiments reveal that all the HAP/CS, Sr1HAP/CS, Sr5HAP/CS and Sr10HAP/CS nanohybrid scaffolds possess excellent cytocompatibility with the favorable adhesion, spreading and proliferation of human bone marrow mesenchymal stem cells (hBMSCs). The Sr5HAP nanocrystals in the scaffolds do not affect the adhesion, spreading of hBMSCs, but they contribute remarkably to cell proliferation and osteogenic differentiation. As compared with the HAP/CS nanohybrid scaffold, the released Sr 2+ ions from the SrHAP/CS nanohybrid scaffolds enhance alkaline phosphatase (ALP) activity, extracellular matrix (ECM) mineralization and osteogenic-related COL-1 and ALP expression levels. Especially, the Sr5HAP/CS nanohybrid scaffolds exhibit the best osteoinductivity among four groups because of the synergetic effect between Ca 2+ and Sr 2+ ions. Hence, the Sr5HAP/CS nanohybrid scaffolds with excellent cytocompatibility and osteogenic property have promising application for bone tissue engineering. Copyright © 2016. Published

Conducting Polymer-Based Nanohybrid Transducers: A Potential Route to High Sensitivity and Selectivity Sensors

PubMed Central

Park, Seon Joo; Kwon, Oh Seok; Lee, Ji Eun; Jang, Jyongsik; Yoon, Hyeonseok

2014-01-01

The development of novel sensing materials provides good opportunities to realize previously unachievable sensor performance. In this review, conducting polymer-based nanohybrids are highlighted as innovative transducers for high-performance chemical and biological sensing devices. Synthetic strategies of the nanohybrids are categorized into four groups: (1) impregnation, followed by reduction; (2) concurrent redox reactions; (3) electrochemical deposition; (4) seeding approach. Nanocale hybridization of conducting polymers with inorganic components can lead to improved sorption, catalytic reaction and/or transport behavior of the material systems. The nanohybrids have thus been used to detect nerve agents, toxic gases, volatile organic compounds, glucose, dopamine, and DNA. Given further advances in nanohybrids synthesis, it is expected that sensor technology will also evolve, especially in terms of sensitivity and selectivity. PMID:24561406

Glycogen-gold nanohybrid escalates the potency of silymarin.

PubMed

Kandimalla, Raghuram; Dash, Suvakanta; Bhowal, Ashim Chandra; Kalita, Sanjeeb; Talukdar, Narayan Chandra; Kundu, Sarathi; Kotoky, Jibon

2017-01-01

In this study, a glycogen-gold nanohybrid was fabricated to enhance the potency of a promising hepatoprotective agent silymarin (Sly) by improving its solubility and gut permeation. By utilizing a facile green chemistry approach, biogenic gold nanoparticles were synthesized from Annona reticulata leaf phytoconstituents in combination with Sly (SGNPs). Further, the SGNPs were aggregated in glycogen biopolymer to yield the therapeutic nanohybrids (GSGNPs). Transmission electron microscopy, UV-Vis spectroscopy, X-ray diffraction, and Fourier transform infrared spectroscopy analysis confirmed the successful formation and conjugation of both SGNPs and GSGNPs. The fabricated nanohybrids showed significant protection against CCl 4 -induced hepatic injury in Wistar rats and maintained natural antioxidant (superoxide dismutase and catalase) levels. Animals treated with GSGNPs (10 mg/kg) and SGNPs (20 mg/kg) retained usual hepatic functions with routine levels of hepatobiliary enzymes (aspartate transferase, alanine transaminase, alkaline phosphatase, and lactate dehydrogenase) and inflammatory markers (interleukin-1β and tumor necrosis factor-α) with minimal lipid peroxidation, whereas those treated with 100 mg/kg of Sly showed the similar effect. These results were also supported by histopathology of the livers where pronounced hepatoprotection with normal hepatic physiology and negligible inflammatory infiltrate were observed. Significant higher plasma C max supported the enhanced bioavailability of Sly upon GSGNPs treatment compared to SGNPs and free Sly. Graphite furnace atomic absorption spectrophotometry analysis also substantiated the efficient delivery of GSGNPs over SGNPs. The fabricated therapeutic nanohybrids were also found to be biocompatible toward human erythrocytes and L929 mouse fibroblast cells. Overall, due to increased solubility, bioavailability and profuse gut absorption; GSGNPs demonstrated tenfold enhanced potency compared to free Sly.

Characterization and Curing Kinetics of Epoxy/Silica Nano-Hybrids

PubMed Central

Yang, Cheng-Fu; Wang, Li-Fen; Wu, Song-Mao; Su, Chean-Cheng

2015-01-01

The sol-gel technique was used to prepare epoxy/silica nano-hybrids. The thermal characteristics, curing kinetics and structure of epoxy/silica nano-hybrids were studied using differential scanning calorimetry (DSC), 29Si nuclear magnetic resonance (NMR) and transmission electron microscopy (TEM). To improve the compatibility between the organic and inorganic phases, a coupling agent was used to modify the diglycidyl ether of bisphenol A (DGEBA) epoxy. The sol-gel technique enables the silica to be successfully incorporated into the network of the hybrids, increasing the thermal stability and improving the mechanical properties of the prepared epoxy/silica nano-hybrids. An autocatalytic mechanism of the epoxy/SiO2 nanocomposites was observed. The low reaction rate of epoxy in the nanocomposites is caused by the steric hindrance in the network of hybrids that arises from the consuming of epoxide group in the network of hybrids by the silica. In the nanocomposites, the nano-scale silica particles had an average size of approximately 35 nm, and the particles were well dispersed in the epoxy matrix, according to the TEM images. PMID:28793616

A nanohybrid system for taste masking of sildenafil.

PubMed

Lee, Ji-Hee; Choi, Goeun; Oh, Yeon-Ji; Park, Je Won; Choy, Young Bin; Park, Mung Chul; Yoon, Yeo Joon; Lee, Hwa Jeong; Chang, Hee Chul; Choy, Jin-Ho

2012-01-01

A nanohybrid was prepared with an inorganic clay material, montmorillonite (MMT), for taste masking of sildenafil (SDN). To further improve the taste-masking efficiency and enhance the drug-release rate, we coated the nanohybrid of SDN-MMT with a basic polymer, polyvinylacetal diethylaminoacetate (AEA). Powder X-ray diffraction and Fourier transform infrared experiments showed that SDN was successfully intercalated into the interlayer space of MMT. The AEA-coated SDN-MMT nanohybrid showed drug release was much suppressed at neutral pH (release rate, 4.70 ± 0.53%), suggesting a potential for drug taste masking at the buccal cavity. We also performed in vitro drug release experiments in a simulated gastric fluid (pH = 1.2) and compared the drug-release profiles of AEA-coated SDN-MMT and Viagra(®), an approved dosage form of SDN. As a result, about 90% of SDN was released from the AEA-coated SDN-MMT during the first 2 hours while almost 100% of drug was released from Viagra(®). However, an in vivo experiment showed that the AEA-coated SDN-MMT exhibited higher drug exposure than Viagra(®). For the AEA-coated SDN-MMT, the area under the plasma concentration- time curve from 0 hours to infinity (AUC(0-∞)) and maximum concentration (C(max)) were 78.8 ± 2.32 μg · hour/mL and 12.4 ± 0.673 μg/mL, respectively, both of which were larger than those obtained with Viagra(®) (AUC(0-∞) = 69.2 ± 3.19 μg · hour/mL; C(max) = 10.5 ± 0.641 μg/mL). Therefore, we concluded that the MMT-based nanohybrid is a promising delivery system for taste masking of SDN with possibly improved drug exposure.

A nanohybrid system for taste masking of sildenafil

PubMed Central

Lee, Ji-Hee; Choi, Goeun; Oh, Yeon-Ji; Park, Je Won; Choy, Young Bin; Park, Mung Chul; Yoon, Yeo Joon; Lee, Hwa Jeong; Chang, Hee Chul; Choy, Jin-Ho

2012-01-01

A nanohybrid was prepared with an inorganic clay material, montmorillonite (MMT), for taste masking of sildenafil (SDN). To further improve the taste-masking efficiency and enhance the drug-release rate, we coated the nanohybrid of SDN–MMT with a basic polymer, polyvinylacetal diethylaminoacetate (AEA). Powder X-ray diffraction and Fourier transform infrared experiments showed that SDN was successfully intercalated into the interlayer space of MMT. The AEA-coated SDN–MMT nanohybrid showed drug release was much suppressed at neutral pH (release rate, 4.70 ± 0.53%), suggesting a potential for drug taste masking at the buccal cavity. We also performed in vitro drug release experiments in a simulated gastric fluid (pH = 1.2) and compared the drug-release profiles of AEA-coated SDN–MMT and Viagra®, an approved dosage form of SDN. As a result, about 90% of SDN was released from the AEA-coated SDN–MMT during the first 2 hours while almost 100% of drug was released from Viagra®. However, an in vivo experiment showed that the AEA-coated SDN–MMT exhibited higher drug exposure than Viagra®. For the AEA-coated SDN–MMT, the area under the plasma concentration– time curve from 0 hours to infinity (AUC0-∞) and maximum concentration (Cmax) were 78.8 ± 2.32 μg · hour/mL and 12.4 ± 0.673 μg/mL, respectively, both of which were larger than those obtained with Viagra® (AUC0-∞ = 69.2 ± 3.19 μg · hour/mL; Cmax = 10.5 ± 0.641 μg/mL). Therefore, we concluded that the MMT-based nanohybrid is a promising delivery system for taste masking of SDN with possibly improved drug exposure. PMID:22619517

Core@shell@shell structured carbon-based magnetic ternary nanohybrids: Synthesis and their enhanced microwave absorption properties

NASA Astrophysics Data System (ADS)

Yang, Erqi; Qi, Xiaosi; Xie, Ren; Bai, Zhongchen; Jiang, Yang; Qin, Shuijie; Zhong, Wei; Du, Youwei

2018-05-01

High encapsulation efficiency of core@shell@shell structured carbon-based magnetic ternary nanohybrids have been synthesized in high yield by chemical vapor deposition of acetylene directly over octahedral-shaped Fe2O3 nanoparticles. By controlling the pyrolysis temperature, Fe3O4@Fe3C@carbon nanotubes (CNTs) and Fe@Fe3C@CNTs ternary nanohybrids could be selectively produced. The optimal RL values for the as-prepared ternary nanohybrids could reach up to ca. -46.7, -52.7 and -29.5 dB, respectively. The excellent microwave absorption properties of the obtaiend ternary nanohybrids were proved to ascribe to the quarter-wavelength matching model. Moreover, the as-prepared Fe@Fe3C@CNTs ternary nanohybrids displayed remarkably enhanced EM wave absorption capabilities compared to Fe3O4@Fe3C@CNTs due to their excellent dielectric loss abilities, good complementarities between the dielectric loss and the magnetic loss, and high attenuation constant. Generally, this strategy can be extended to explore other categories of core@shell or core@shell@shell structured carbon-based nanohybrids, which is very beneficial to accelerate the advancements of high performance MAMs.

Functional single-wall carbon nanotube nanohybrids--associating SWNTs with water-soluble enzyme model systems.

PubMed

Guldi, Dirk M; Rahman, G M Aminur; Jux, Norbert; Balbinot, Domenico; Hartnagel, Uwe; Tagmatarchis, Nikos; Prato, Maurizio

2005-07-13

We succeeded in integrating single-wall carbon nanotubes (SWNTs), several water-soluble pyrene derivatives (pyrene(-)), which bear negatively charged ionic headgroups, and a series of water-soluble metalloporphyrins (MP(8+)) into functional nanohybrids through a combination of associative van der Waals and electrostatic interactions. The resulting SWNT/pyrene(-) and SWNT/pyrene(-)/MP(8+) were characterized by spectroscopic and microscopic means and were found to form stable nanohybrid structures in aqueous media. A crucial feature of our SWNT/pyrene(-) and SWNT/pyrene(-)/MP(8)(+) is that an efficient exfoliation of the initial bundles brings about isolated nanohybrid structures. When the nanohybrid systems are photoexcited with visible light, a rapid intrahybrid charge separation causes the reduction of the electron-accepting SWNT and, simultaneously, the oxidation of the electron-donating MP(8)(+). Transient absorption measurements confirm that the radical ion pairs are long-lived, with lifetimes in the microsecond range. Particularly beneficial are charge recombination dynamics that are located deep in the Marcus-inverted region. We include, for the first time, work devoted to exploring and testing FeP(8)(+) and CoP(8)(+) in donor-acceptor nanohybrids.

Nanoparticle induced piezoelectric, super toughened, radiation resistant, multi-functional nanohybrids.

PubMed

Tiwari, Vimal K; Shripathi, T; Lalla, N P; Maiti, Pralay

2012-01-07

We have developed multifunctional nanohybrids of poly(vinylidene fluoride-co-chlorotrifluoroethylene) (CTFE) with a small percentage of surface modified inorganic layered silicate showing dramatic improvement in toughness, radiation resistant and piezoelectric properties vis-à-vis pristine polymer. Massive intercalation (d(001) 1.8 → 3.9 nm) of polymer inside the nanoclay galleries and unique crystallization behavior of the fluoropolymer on the surface of individual silicate layer has been reported. Toughness in the nanohybrid increases more than three orders of magnitude as compared to pure CTFE. High energy radiation (80 MeV Si(+7)) causes chain session, amorphization and creates olefinic bonds in the pure polymer while the nanohybrids are radiation resistant at a similar dose. Nanoclay induces the metastable piezoelectric β-phase in CTFE, suitable for sensor and actuator application. Molecular level changes after irradiation and controlled morphology for smart membrane have been confirmed by using spectroscopy, sol-gel technique, surface morphology studies and in situ residual gas analysis.

In Vitro Wear Resistance of Nano-Hybrid Composite Denture Teeth.

PubMed

Munshi, Nabeel; Rosenblum, Marc; Jiang, Shuying; Flinton, Robert

2017-04-01

To evaluate the wear resistance of nano-hybrid composite denture teeth as compared to two commonly used denture teeth: interpenetrating polymer network (IPN) and double crosslinking polymethylmethacrylate (PMMA) denture teeth. 18 styli and 18 disk specimens were prepared from the three denture tooth materials: nano-hybrid composite, IPN, and double crosslinking PMMA. The specimens were mounted in a two-body wear testing machine to simulate chewing in the complete denture. The amount of wear from the styli specimens were measured before and after using a digital micrometer, and the depth of the wear track from the disk specimens was measured using a noncontact 3D optical profilometer. The total wear from each denture tooth group was compared using one-way ANOVA with a 0.05 significance level. A Tukey post hoc test was used to determine differences between the three groups. The mean total wear in the nano-hybrid composite teeth group was 1.16 mm, SD = 0.5 mm, statistically significantly higher (p ≤ 0.0001) than the IPN (mean = 0.13 mm, SD = 0.05) and double crosslinking PMMA tooth groups (mean = 0.31 mm, SD = 0.19). There was no statistically significant difference between IPN denture teeth and double crosslinking PMMA denture teeth in the amount of wear. Nano-hybrid composite denture teeth exhibited statistically significantly more wear than the IPN and double crosslinking PMMA denture teeth. © 2015 by the American College of Prosthodontists.

Band edge engineering of TiO2@DNA nanohybrids and implications for capacitive energy storage devices

NASA Astrophysics Data System (ADS)

Imani, Roghayeh; Pazoki, Meysam; Tiwari, Ashutosh; Boschloo, G.; Turner, Anthony P. F.; Kralj-Iglič, V.; Iglič, Aleš

2015-06-01

Novel mesoporous TiO2@DNA nanohybrid electrodes, combining covalently encoded DNA with mesoporous TiO2 microbeads using dopamine as a linker, were prepared and characterised for application in supercapacitors. Detailed information about donor density, charge transfer resistance and chemical capacitance, which have an important role in the performance of an electrochemical device, were studied by electrochemical methods. The results indicated the improvement of electrochemical performance of the TiO2 nanohybrid electrode by DNA surface functionalisation. A supercapacitor was constructed from TiO2@DNA nanohybrids with PBS as the electrolyte. From the supercapacitor experiment, it was found that the addition of DNA played an important role in improving the specific capacitance (Cs) of the TiO2 supercapacitor. The highest Cs value of 8 F g-1 was observed for TiO2@DNA nanohybrids. The nanohybrid electrodes were shown to be stable over long-term cycling, retaining 95% of their initial specific capacitance after 1500 cycles.Novel mesoporous TiO2@DNA nanohybrid electrodes, combining covalently encoded DNA with mesoporous TiO2 microbeads using dopamine as a linker, were prepared and characterised for application in supercapacitors. Detailed information about donor density, charge transfer resistance and chemical capacitance, which have an important role in the performance of an electrochemical device, were studied by electrochemical methods. The results indicated the improvement of electrochemical performance of the TiO2 nanohybrid electrode by DNA surface functionalisation. A supercapacitor was constructed from TiO2@DNA nanohybrids with PBS as the electrolyte. From the supercapacitor experiment, it was found that the addition of DNA played an important role in improving the specific capacitance (Cs) of the TiO2 supercapacitor. The highest Cs value of 8 F g-1 was observed for TiO2@DNA nanohybrids. The nanohybrid electrodes were shown to be stable over long-term cycling

Graphene oxide/manganese ferrite nanohybrids for magnetic resonance imaging, photothermal therapy and drug delivery.

PubMed

Yang, Yan; Shi, Haili; Wang, Yapei; Shi, Benzhao; Guo, Linlin; Wu, Dongmei; Yang, Shiping; Wu, Huixia

2016-01-01

Superparamagnetic manganese ferrite (MnFe2O4) nanoparticles have been deposited on graphene oxide (GO) by the thermal decomposition of manganese (II) acetylacetonate and iron (III) acetylacetonate precursors in triethylene glycol. The resulting GO/MnFe2O4 nanohybrids show very low cytotoxicity, negligible hemolytic activity, and imperceptible in vivo toxicity. In vitro and in vivo magnetic resonance imaging experiments demonstrate that GO/MnFe2O4 nanohybrids could be used as an effective T2 contrast agent. The strong optical absorbance in the near-infrared (NIR) region and good photothermal stability of GO/MnFe2O4 nanohybrids result in the highly efficient photothermal ablation of cancer cells. GO/MnFe2O4 nanohybrids can be further loaded with doxorubicin (DOX) by π-π conjugate effect for chemotherapy. DOX release from GO/MnFe2O4 is significantly influenced by pH and can be triggered by NIR laser. The enhanced cancer cell killing by GO/MnFe2O4/DOX composites has been achieved when irradiated with near-infrared light, suggesting that the nanohybrids could deliver both DOX chemotherapy and photothermal therapy with a synergistic effect. © The Author(s) 2015.

MOF-derived nanohybrids for electrocatalysis and energy storage: current status and perspectives.

PubMed

Zhang, Hong; Liu, Ximeng; Wu, Yue; Guan, Cao; Cheetham, Anthony K; Wang, John

2018-03-27

More than 20 000 MOFs have been reported to date, with different combinations of metal ions/centers and organic linkers, and they can be grown into various 3D, 2D, 1D and 0D morphologies. The flexibility in control over varying length scales from atomic scale up to bulk structure allows access to an almost endless variety of MOF-based and MOF-derived materials. Indeed, MOFs themselves have been studied as a class of useful functional materials. More remarkably, extensive research conducted in recent years has shown that MOFs are exceptionally good precursors for a large variety of nanohybrids as active materials in both electrocatalysis and energy storage. As they already contain both carbon and well-dispersed metal atoms, MOFs can be converted to conductive carbons decorated with active metal species and doping elements through appropriate pyrolysis. Due to the great diversity accessible in the composition, structure, and morphology of MOFs, several types of MOF-derived nanohybrids are now among the best performing materials both for electrocatalysts and electrodes in various energy conversion and storage devices. In addition to mesoporous nano-carbons, both doped and undoped, carbon-metal nanohybrids, and carbon-compound nanohybrids, there are several types of core@shell, encapsulated nanostructures, embedded nanosystems and heterostructures that have been developed from MOFs recently. They can be made in either free-standing forms, nano- or micro-powders, grown on appropriate conducting substrates, or assembled together with other active materials. During the MOF to active material conversion, other active species or precursors can be inserted into the MOF-derived nanostructures or assembled on surfaces, leading to uniquely new porous nanostructures. These MOF-derived active materials for electrocatalysis and energy storage are nanohybrids consisting of more than functional components that are purposely integrated together at desired length scales for much

MoS2 @HKUST-1 Flower-Like Nanohybrids for Efficient Hydrogen Evolution Reactions.

PubMed

Wang, Chengli; Su, Yingchun; Zhao, Xiaole; Tong, Shanshan; Han, Xiaojun

2018-01-24

A novel MoS 2 -based flower-like nanohybrid for hydrogen evolution was fabricated through coating the Cu-containing metal-organic framework (HKUST-1) onto MoS 2 nanosheets. It is the first time that MoS 2 @HKUST-1 nanohybrids have been reported for the enhanced electrochemical performance of HER. The morphologies and components of the MoS 2 @HKUST-1 flower-like nanohybrids were characterized by scanning electron microscopy, X-ray diffraction analysis and Fourier transform infrared spectroscopy. Compared with pure MoS 2 , the MoS 2 @HKUST-1 hybrids exhibit enhanced performance on hydrogen evolution reaction with an onset potential of -99 mV, a smaller Tafel slope of 69 mV dec -1 , and a Faradaic efficiency of nearly 100 %. The MoS 2 @HKUST-1 flower-like nanohybrids exhibit excellent stability in acidic media. This design opens new possibilities to effectively synthesize non-noble metal catalysts with high performance for the hydrogen evolution reaction (HER). © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

The effect of toothbrush bristle stiffness on nanohybrid surface roughness

NASA Astrophysics Data System (ADS)

Zairani, O.; Irawan, B.; Damiyanti, M.

2017-08-01

The surface of a restoration can be affected by toothpaste containing abrasive agents and the stiffness of toothbrush bristles. Objective: To identify the effect of toothbrush bristle stiffness on nanohybrid surface roughness. Methods: Sixteen nanohybrid specimens were separated into two groups. The first group was brushed using soft-bristle toothbrushes, and the second group was brushed using medium-bristle toothbrushes. Media such as aqua bides was used for brushing in both groups. Brushing was done 3 times for 5 minutes. Surface roughness was measured initially and at 5, 10, and 15 minutes using a surface roughness tester. Results: The results, tested with One-Way ANOVA and Independent Samples t Test, demonstrated that after brushing for 15 minutes, the soft-bristle toothbrush group showed a significantly different value (p < 0.05) of nanohybrid surface roughness. The group using medium-bristle toothbrushes showed the value of nano hybrid surface roughness significant difference after brushing for 10 minutes. Conclusion: Roughness occurs more rapidly when brushing with medium-bristle tooth brushes than when brushing with soft-bristle toothbrushes.

Self-Assembled α-Fe2O3 mesocrystals/graphene nanohybrid for enhanced electrochemical capacitors.

PubMed

Yang, Shuhua; Song, Xuefeng; Zhang, Peng; Sun, Jing; Gao, Lian

2014-06-12

Self-assembled α-Fe2O3 mesocrystals/graphene nanohybrids have been successfully synthesized and have a unique mesocrystal porous structure, a large specific surface area, and high conductivity. Mesocrystal structures have recently attracted unparalleled attention owing to their promising application in energy storage as electrochemical capacitors. However, mesocrystal/graphene nanohybrids and their growth mechanism have not been clearly investigated. Here we show a facile fabrication of short rod-like α-Fe2O3 mesocrystals/graphene nanohybrids by self-assembly of FeOOH nanorods as the primary building blocks on graphene under hydrothermal conditions, accompanied and promoted by concomitant phase transition from FeOOH to α-Fe2O3. A systematic study of the formation mechanism is also presented. The galvanostatic charge/discharge curve shows a superior specific capacitance of the as-prepared α-Fe2O3 mesocrystals/graphene nanohybrid (based on total mass of active materials), which is 306.9 F g(-1) at 3 A g(-1) in the aqueous electrolyte under voltage ranges of up to 1 V. The nanohybrid with unique sufficient porous structure and high electrical conductivity allows for effective ion and charge transport in the whole electrode. Even at a high discharge current density of 10 A g(-1), the enhanced ion and charge transport still yields a higher capacitance (98.2 F g(-1)), exhibiting enhanced rate capability. The α-Fe2O3 mesocrystal/graphene nanohybrid electrode also demonstrates excellent cyclic performance, which is superior to previously reported graphene-based hematite electrode, suggesting it is highly stable as an electrochemical capacitor. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Silica-F127 nanohybrid-encapsulated manganese oxide nanoparticles for optimized T1 magnetic resonance relaxivity

NASA Astrophysics Data System (ADS)

Wei Hsu, Benedict You; Wang, Miao; Zhang, Yu; Vijayaragavan, Vimalan; Wong, Siew Yee; Yuang-Chi Chang, Alex; Bhakoo, Kishore Kumar; Li, Xu; Wang, John

2013-12-01

To properly engineer MnO nanoparticles (MONPs) of high r1 relaxivity, a nanohybrid coating consisting of silica and F127 (PEO106PPO70PEO106) is designed to encapsulate MONPs. Achieved by an interfacial templating scheme, the nanohybrid encapsulating layer is highly permeable and hydrophilic to allow for an optimal access of water molecules to the encapsulated manganese oxide core. Hence, the efficacy of MONPs as MRI contrast agents is significantly improved, as demonstrated by an enhancement of the MR signal measured with a pre-clinical 7.0 T MRI scanner. The nanohybrid encapsulation strategy also confers high colloidal stability to the hydrophobic MONPs by the surface decoration of PEO chains and a small overall diameter (<100 nm) of the PEO-SiO2 nanohybrid-encapsulated MONPs (PEOMSNs). The PEOMSNs are not susceptible to Mn-ion leaching, and their biocompatibility is affirmed by a low toxicity profile. Moreover, these hybrid nanocapsules exhibit a nano-rattle structure, which would favor the facile loading of various therapeutic reagents for theranostic applications.To properly engineer MnO nanoparticles (MONPs) of high r1 relaxivity, a nanohybrid coating consisting of silica and F127 (PEO106PPO70PEO106) is designed to encapsulate MONPs. Achieved by an interfacial templating scheme, the nanohybrid encapsulating layer is highly permeable and hydrophilic to allow for an optimal access of water molecules to the encapsulated manganese oxide core. Hence, the efficacy of MONPs as MRI contrast agents is significantly improved, as demonstrated by an enhancement of the MR signal measured with a pre-clinical 7.0 T MRI scanner. The nanohybrid encapsulation strategy also confers high colloidal stability to the hydrophobic MONPs by the surface decoration of PEO chains and a small overall diameter (<100 nm) of the PEO-SiO2 nanohybrid-encapsulated MONPs (PEOMSNs). The PEOMSNs are not susceptible to Mn-ion leaching, and their biocompatibility is affirmed by a low toxicity profile

Effects of silica–gentamicin nanohybrids on osteogenic differentiation of human osteoblast-like SaOS-2 cells

PubMed Central

He, Wei; Mosselhy, Dina A; Li, Xiaoning; Yang, Xing; Yue, Lina; Hannula, Simo-Pekka

2018-01-01

Introduction In recent years, there has been an increasing interest in silica (SiO2) nanoparticles (NPs) as drug delivery systems. This interest is mainly attributed to the ease of their surface functionalization for drug loading. In orthopedic applications, gentamicin-loaded SiO2 NPs (nanohybrids) are frequently utilized for their prolonged antibacterial effects. Therefore, the possible adverse effects of SiO2–gentamicin nanohybrids on osteogenesis of bone-related cells should be thoroughly investigated to ensure safe applications. Materials and methods The effects of SiO2–gentamicin nanohybrids on the cell viability and osteogenic differentiation of human osteoblast-like SaOS-2 cells were investigated, together with native SiO2 NPs and free gentamicin. Results The results of Cell Count Kit-8 (CCK-8) assay show that both SiO2–gentamicin nanohybrids and native SiO2 NPs reduce cell viability of SaOS-2 cells in a dose-dependent manner. Regarding osteogenesis, SiO2–gentamicin nanohybrids and native SiO2 NPs at the concentration range of 31.25–125 μg/mL do not influence the osteogenic differentiation capacity of SaOS-2 cells. At a high concentration (250 μg/mL), both materials induce a lower expression of alkaline phosphatase (ALP) but an enhanced mineralization. Free gentamicin at concentrations of 6.26 and 9.65 μg/mL does not significantly influence the cell viability and osteogenic differentiation capacity of SaOS-2 cells. Conclusions The results of this study suggest that both SiO2–gentamicin nanohybrids and SiO2 NPs show cytotoxic effects to SaOS-2 cells. Further investigation on the effects of SiO2–gentamicin nanohybrids on the behaviors of stem cells or other regular osteoblasts should be conducted to make a full evaluation of the safety of SiO2–gentamicin nanohybrids in orthopedic applications. PMID:29445277

Graphene oxide based nanohybrid proton exchange membranes for fuel cell applications: An overview.

PubMed

Pandey, Ravi P; Shukla, Geetanjali; Manohar, Murli; Shahi, Vinod K

2017-02-01

In the context of many applications, such as polymer composites, energy-related materials, sensors, 'paper'-like materials, field-effect transistors (FET), and biomedical applications, chemically modified graphene was broadly studied during the last decade, due to its excellent electrical, mechanical, and thermal properties. The presence of reactive oxygen functional groups in the grapheme oxide (GO) responsible for chemical functionalization makes it a good candidate for diversified applications. The main objectives for developing a GO based nanohybrid proton exchange membrane (PEM) include: improved self-humidification (water retention ability), reduced fuel crossover (electro-osmotic drag), improved stabilities (mechanical, thermal, and chemical), enhanced proton conductivity, and processability for the preparation of membrane-electrode assembly. Research carried on this topic may be divided into protocols for covalent grafting of functional groups on GO matrix, preparation of free-standing PEM or choice of suitable polymer matrix, covalent or hydrogen bonding between GO and polymer matrix etc. Herein, we present a brief literature survey on GO based nano-hybrid PEM for fuel cell applications. Different protocols were adopted to produce functionalized GO based materials and prepare their free-standing film or disperse these materials in various polymer matrices with suitable interactions. This review article critically discussed the suitability of these PEMs for fuel cell applications in terms of the dependency of the intrinsic properties of nanohybrid PEMs. Potential applications of these nanohybrid PEMs, and current challenges are also provided along with future guidelines for developing GO based nanohybrid PEMs as promising materials for fuel cell applications. Copyright © 2016 Elsevier B.V. All rights reserved.

Multifunctional carbon-coated magnetic sensing graphene oxide-cyclodextrin nanohybrid for potential cancer theranosis

NASA Astrophysics Data System (ADS)

Hsu, Yu-Hsuan; Hsieh, Hui-Ling; Viswanathan, Geetha; Voon, Siew Hui; Kue, Chin Siang; Saw, Wen Shang; Yeong, Chai Hong; Azlan, Che Ahmad; Imae, Toyoko; Kiew, Lik Voon; Lee, Hong Boon; Chung, Lip Yong

2017-11-01

We functionalized graphene oxide (GO) with cyclodextrin (CD) to increase the drug loading and cellular uptake of GO, and bound the GO-CD to carbon-coated iron nanoparticles (Fe@C) with superparamagnetic properties for potential magnetic-directed drug delivery and as a diagnostic agent. The GO-CD/Fe@C was loaded with an anticancer drug, doxorubicin (DOX), to form a multifunctional GO-CD/Fe@C/DOX nanohybrid. A cumulative increase in DOX loading was observed probably due to DOX adsorption to the graphitic domains in Fe@C and also to the GO-CD. In acidic pH that resembles the pH of the tumor environment, a higher amount of DOX was released from the GO-CD/Fe@C/DOX nanohybrid when compared to the amount released at physiological pH. The signal intensity and the contrast enhancement in magnetic resonance imaging of Fe@C decreased with its concentration. Besides, the cellular uptake of GO-CD/Fe@C/DOX nanohybrid was significantly higher by 2.5-fold than that of Fe@C/DOX in MDA-MB-231 human breast cancer model. The nanohybrids were internalized into the tumor cells via an energy-dependent process and localized mainly in the nuclei, where it exerts its cytotoxic effect, and some in the lysosomes and mitochondria. This has resulted in significant cytotoxicity in tumor cells treated with GO-CD/Fe@C/DOX. These findings highlight the potential use of multifunctional GO-CD/Fe@C nanohybrid for magnetic sensing anticancer drug delivery to tumor cells. [Figure not available: see fulltext.

Facile synthesis of Au-ZnO plasmonic nanohybrids for highly efficient photocatalytic degradation of methylene blue

NASA Astrophysics Data System (ADS)

Kuriakose, Sini; Sahu, Kavita; Khan, Saif A.; Tripathi, A.; Avasthi, D. K.; Mohapatra, Satyabrata

2017-02-01

Au-ZnO plasmonic nanohybrids were synthesized by a facile two step process. In the first step, nanostructured ZnO thin films were prepared by carbothermal evaporation followed by thermal annealing in oxygen atmosphere. Deposition of ultrathin Au films onto the nanostructured ZnO thin films by sputtering combined with thermal annealing resulted in the formation of Au-ZnO plasmonic nanohybrid thin films. The structural, optical, plasmonic and photocatalytic properties of the Au-ZnO nanohybrid thin films were studied. XRD studies on the Au-ZnO hybrid thin films revealed the presence of Au and ZnO nanostructures. UV-visible absorption studies showed two peaks corresponding to the excitonic absorption of ZnO nanostructures in the UV region and the surface plasmon resonance (SPR) absorption of Au nanoparticles in the visible region. The Au-ZnO nanohybrid thin films annealed at 400 °C showed enhanced photocatalytic activity as compared to nanostructrured ZnO thin films towards sun light driven photocatalytic degradation of methylene blue (MB) dye in water. The observed enhanced photocatalytic activity of Au-ZnO plasmonic nanohybrids is attributed to the efficient suppression of the recombination of photogenerated charge carriers in ZnO due to the strong electron scavenging action of Au nanoparticles combined with the improved sun light utilization capability of Au-ZnO nanohybrids coming from the plasmonic response of Au nanoparticles decorating ZnO nanostructures.

Development of antiproliferative nanohybrid compound with controlled release property using ellagic acid as the active agent

PubMed Central

Hussein, Mohd Zobir; Al Ali, Samer Hasan; Zainal, Zulkarnain; Hakim, Muhammad Nazrul

2011-01-01

An ellagic acid (EA)–zinc layered hydroxide (ZLH) nanohybrid (EAN) was synthesized under a nonaqueous environment using EA and zinc oxide (ZnO) as the precursors. Powder X-ray diffraction showed that the basal spacing of the nanohybrid was 10.4 Å, resulting in the spatial orientation of EA molecules between the interlayers of 22.5° from z-axis with two negative charges at 8,8′ position of the molecules pointed toward the ZLH interlayers. FTIR study showed that the intercalated EA spectral feature is generally similar to that of EA, but with bands slightly shifted. This indicates that some chemical bonding of EA presence between the nanohybrid interlayers was slightly changed, due to the formation of host–guest interaction. The nanohybrid is of mesopores type with 58.8% drug loading and enhanced thermal stability. The release of the drug active, EA from the nanohybrid was found to be sustained and therefore has good potential to be used as a drug controlled-release formulation. In vitro bioassay study showed that the EAN has a mild effect on the hepatocytes cells, similar to its counterpart, free EA. PMID:21796241

Single-step preparation of TiO2/MWCNT Nanohybrid materials by laser pyrolysis and application to efficient photovoltaic energy conversion.

PubMed

Wang, Jin; Lin, Yaochen; Pinault, Mathieu; Filoramo, Arianna; Fabert, Marc; Ratier, Bernard; Bouclé, Johann; Herlin-Boime, Nathalie

2015-01-14

This paper presents the continuous-flowand single-step synthesis of a TiO2/MWCNT (multiwall carbon nanotubes) nanohybrid material. The synthesis method allows achieving high coverage and intimate interface between the TiO2particles and MWCNTs, together with a highly homogeneous distribution of nanotubes within the oxide. Such materials used as active layer in theporous photoelectrode of solid-state dye-sensitized solar cells leads to a substantial performance improvement (20%) as compared to reference devices.

Dual-fluorophore Raspberry-like Nanohybrids for Ratiometric pH Sensing.

PubMed

Acquah, Isaac; Roh, Jinkyu; Ahn, Dong June

2017-07-18

We report on the development of raspberry-like silica structures formed by the adsorption of 8-hydroxypyrene-1,3,6-trisulfonate (HPTS)@silica nanoparticles (NPs) on rhodamine B isothiocyanate (RBTIC)@silica NPs for ratiometric fluorescence-based pH sensing. To overcome the well-known problem of dye leaching which occurs during encapsulation of anionic HPTS dye in silica NPs, we utilized a polyelectrolyte-assisted incorporation of the anionic HPTS. The morphological and optical characterization of the as-synthesized dye-doped NPs and the resulting nanohybrids were carried out. The pH-sensitive dye, HPTS, incorporated in the HPTS-doped silica NPs provided a pH-dependent fluorescence response while the RBITC-doped silica provided the reference signal for ratiometric sensing. We evaluated the effectiveness of the nanohybrids for pH sensing; the ratio of the fluorescence emission intensity at 510 nm and 583 nm at excitation wavelengths of 454 nm and 555 nm, respectively. The results showed a dynamic response in the acidic pH range. With this approach, nanohybrids containing different dyes or receptors could be developed for multifunctioning and multiplexing applications. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis and controlled release properties of 2,4-dichlorophenoxy acetate–zinc layered hydroxide nanohybrid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bashi, Abbas M., E-mail: abbasmatrood@yahoo.com; Hussein, Mohd Zobir; Zainal, Zulkarnain

2013-07-15

Direct reaction of ZnO with 2,4-dichlorophenoxyacetic acid (24D) solutions of different concentrations allows obtaining new organic–inorganic nanohybrid materials formed by intercalation of 24D into interlayers of zinc layered hydroxide (ZLH). XRD patterns show a progressive evolution of the structure as 24D concentration increases. The nanohybrid obtained at higher 24D concentration (24D–ZLH(0.4)) reveals a well ordered layered structure with two different basal spacings at 25.2 Å and 24 Å. The FTIR spectrum showing the vibrations bands of the functional groups of 24D and of the ZLH confirms the intercalation. SEM images are in agreement with the structural evolution observed by XRDmore » and reveal the ribbon morphology of the nanohybrids. The release studies of 24D showed a rapid release of 94% for the first 100 min governed by the pseudo-second order kinetic model. - Graphical abstract: The phenomenon indicates that the optical energy gap is enlarged with the increase of molar concentrations in 2,4-dichlorophenoxy acetate anion content into ZnO to create a ZLH–24D nanohybrid. - Highlights: • Nanohybrid was synthesized from 2,4-dichlorophenoxy acetate with-Zinc LHD, using wet chemistry. • Characterized using SEM, TEM, EDX, FTIR, XRD and TGA. • Ribbon-shaped 24D–Zn-layered hydroxide nanoparticles with (003) diffractions of 2.5 nm phase were synthesized.« less

A General Strategy for Nanohybrids Synthesis via Coupled Competitive Reactions Controlled in a Hybrid Process

PubMed Central

Wang, Rongming; Yang, Wantai; Song, Yuanjun; Shen, Xiaomiao; Wang, Junmei; Zhong, Xiaodi; Li, Shuai; Song, Yujun

2015-01-01

A new methodology based on core alloying and shell gradient-doping are developed for the synthesis of nanohybrids, realized by coupled competitive reactions, or sequenced reducing-nucleation and co-precipitation reaction of mixed metal salts in a microfluidic and batch-cooling process. The latent time of nucleation and the growth of nanohybrids can be well controlled due to the formation of controllable intermediates in the coupled competitive reactions. Thus, spatiotemporal-resolved synthesis can be realized by the hybrid process, which enables us to investigate nanohybrid formation at each stage through their solution color changes and TEM images. By adjusting the bi-channel solvents and kinetic parameters of each stage, the primary components of alloyed cores and the second components of transition metal doping ZnO or Al2O3 as surface coatings can be successively formed. The core alloying and shell gradient-doping strategy can efficiently eliminate the crystal lattice mismatch in different components. Consequently, varieties of gradient core-shell nanohybrids can be synthesized using CoM, FeM, AuM, AgM (M = Zn or Al) alloys as cores and transition metal gradient-doping ZnO or Al2O3 as shells, endowing these nanohybrids with unique magnetic and optical properties (e.g., high temperature ferromagnetic property and enhanced blue emission). PMID:25818342

Nanohybrids from NiCoAl-LDH coupled with carbon for pseudocapacitors: understanding the role of nano-structured carbon

NASA Astrophysics Data System (ADS)

Yu, Chang; Yang, Juan; Zhao, Changtai; Fan, Xiaoming; Wang, Gang; Qiu, Jieshan

2014-02-01

Transition metal layered double hydroxides (LDHs) are one of the great potential electrode materials for pseudocapacitors. However, the aggregation and low conductivity of these metal compounds will constrain electrolyte ion and electron transfer and further affect their electrochemical performances. The nano-structured carbon coupled with the LDH matrix can act as an active component or conducting scaffold to enhance or improve the rate capacity and cycle life. Here, various nano-structured carbon species, including zero-dimensional carbon black (CB), one-dimensional carbon nanotubes (CNTs), two-dimensional reduced graphene oxide (RGO), and CNT/RGO composites were used to couple with the NiCoAl-LDHs to construct LDH-carbon nanohybrid electrodes for pseudocapacitors, and the role of the nanostructured carbon was investigated and discussed in terms of the pore structure of nanohybrids and electrical conductivity. The results show that all of the carbons can be well incorporated into the LDH nanosheets to form homogeneous nanohybrid materials. The pore structure properties and electrical conductivity of nanohybrids have statistically significant effects on the electrochemical performances of the LDH-carbon nanohybrids. Of the electrodes adopted, the nanohybrid electrode consisting of NiCoAl-LDHs, CNTs, and RGO exhibits excellent electrochemical performance with a specific capacitance as high as 1188 F g-1 at a current density of 1 A g-1 due to the synergistic effect of NiCoAl-LDHs, RGO, and CNTs, in which the RGO nanosheets are favorable for high specific surface area while the CNT has a fast electron transport path for enhancing the electrical conductivity of nanohybrids. This will shed a new light on the effect of nano-structured carbon within the electrode matrix on the electrochemical activity and open a new way for the carbon-related electrode configuration/design for supercapacitors, and other energy storage and conversion devices.Transition metal layered

Hydrothermal synthesis of red phosphorus @reduced graphene oxide nanohybrid with enhanced electrochemical performance as anode material of lithium-ion battery

NASA Astrophysics Data System (ADS)

Zhu, Xing; Yuan, Zewei; Wang, Xiaobo; Jiang, Guodong; Xiong, Jian; Yuan, Songdong

2018-03-01

Red phosphorus @reduced graphene oxide (P @rGO) nanohybrid was synthesized via a two-step hydrothermal process. The obtained P @rGO nanohybrid was characterized by TEM, SEM, Raman, XRD and XPS. It was found that the nano-scale red phosphorus encapsulated in the reduced graphene oxide and the existence of phosphorus promote the reduction of graphene oxide. The electrochemical performance of P @rGO nanohybrid as an anode material was investigated by galvanostatic charge/discharge, rate performance, cyclic voltammetry and AC impedance test. With increasing the mass of rGO, the electrochemical performance of P @rGO nanohybrid was significantly enhanced. The first discharge/charge specific capacity of the nanohybrid prepared at optimum condition (P:GO = 7:3) could achieve approximately 2400 mAh/g and 1600 mAh/g respectively and still retained ∼1000 mAh/g after 80 cycles and the coulombic efficiency maintained almost 100%. The enhancement in P @rGO nanohybrid was attributed to the introduction of graphene, which led to the elimination of volume effect and the enhancement of conductively of pure red phosphorus.

ZnO nanoparticles and their acarbose-capped nanohybrids as inhibitors for human salivary amylase.

PubMed

Shaik, Firdoz; Kumar, Anil

2017-04-01

The authors report a controlled synthesis of biocompatible ZnO and acarbose-capped nanohybrids, and examined the inhibition activities of these nanosystems with human salivary α -amylase (HSA) activity. XRD measurements reveal ZnO present in wurtzite phase with hexagonal structure. The average size of ZnO particles for the two studied nanosystems was estimated to lie between 10 to 12 nm using Scherrer equation. These particles depict the onset of absorption at about 320 nm and the band-gap emission at about 370 nm, which are fairly blue shifted as compared with the bulk ZnO and have been understood due to the size quantisation effect. The inhibitory action of thioglycerol capped ZnO nanoparticles (SP1) and acarbose drug (used for diabetes type II) capped ZnO (SP2) for HSA was observed to 61 and72%, respectively. The inhibition activity of the SP1 alone was found to be very similar to that of acarbose and the coating of these particles with drug (SP2) demonstrated an enhancement in inhibition activity of the enzyme by about 30%. From the inhibition studies, it is confirmed that these nanosystems showed better inhibition activity at physiological temperature and pH. These nanosystems are projected to have potential applications in diabetes type II control.

Tailoring of physical properties in highly filled experimental nanohybrid resin composites.

PubMed

Pick, Bárbara; Pelka, Matthias; Belli, Renan; Braga, Roberto R; Lohbauer, Ulrich

2011-07-01

To assess the elastic modulus (EM), volumetric shrinkage (VS), and polymerization shrinkage stress (PSS) of experimental highly filled nanohybrid composites as a function of matrix composition, filler distribution, and density. One regular viscosity nanohybrid composite (Grandio, VOCO, Germany) and one flowable nanohybrid composite (Grandio Flow, VOCO) were tested as references along with six highly filled experimental nanohybrid composites (four Bis-GMA-based, one UDMA-based, and one Ormocer®-based). The experimental composites varied in filler size and density. EM values were obtained from the "three-point bending" load-displacement curve. VS was calculated with Archimedes' buoyancy principle. PSS was determined in 1-mm thick specimens placed between two (poly)methyl methacrylate rods (Ø=6mm) attached to an universal testing machine. Data were analyzed using oneway ANOVA, Tukey's test (α=0.05), and linear regression analyses. The flowable composite exhibited the highest VS and PSS but lowest EM. The PSS was significantly lower with Ormocer. The EM was significantly higher among experimental composites with highest filler levels. No significant differences were found between all other experimental composites regarding VS and PSS. Filler density and size did not influence EM, VS, or PSS. Neither the filler configuration nor matrix composition in the investigated materials significantly influenced composite shrinkage and mechanical properties. The highest filled experimental composite seemed to increase EM by keeping VS and PSS low; however, matrix composition seemed to be the determinant factor for shrinkage and stress development. The Ormocer, with reduced PSS, deserves further investigation. Filler size and density did not influence the tested parameters. Copyright © 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Preparation of hippurate-zinc layered hydroxide nanohybrid and its synergistic effect with tamoxifen on HepG2 cell lines

PubMed Central

Ali, Samer Hasan Hussein Al; Al-Qubaisi, Mothanna; Hussein, Mohd Zobir; Zainal, Zulkarnain; Hakim, Muhammad Nazrul

2011-01-01

Background A new simple preparation method for a hippurate-intercalated zinc-layered hydroxide (ZLH) nanohybrid has been established, which does not need an anion-exchange procedure to intercalate the hippurate anion into ZLH interlayers. Methods The hippuric acid nanohybrid (HAN) was prepared by direct reaction of an aqueous suspension of zinc oxide with a solution of hippuric acid via a one-step method. Results The basal spacing of the nanohybrid was 21.3 Å, indicating that the hippurate anion was successfully intercalated into the interlayer space of ZLH, and arranged in a monolayer fashion with the carboxylate group pointing toward the ZLH inorganic interlayers. A Fourier transform infrared study confirmed the formation of the nanohybrid, while thermogravimetry and differential thermogravimetry analyses showed that the thermal stability of the nanohybrid was markedly enhanced. The loading of hippurate in the nanohybrid was estimated to be about 38.7% (w/w), and the release of hippurate from the nanohybrid was of a controlled manner, and therefore the resulting material was suitable for use as a controlled-release formulation. HAN has synergistic properties with tamoxifen toward a HepG2 cell line, with an IC50 value of 0.35 compared with hippurate. In the antiproliferative assay, the ratio of viable cells account for cells treated by the combination tamoxifen with HAN to untreated cells was sharply reduced from 66% to 13% after 24 and 72 hours, respectively. Conclusion The release of hippuric acid anions from HAN occurred in a controlled manner, and the resulting material is suitable for a controlled-release formulation. PMID:22163163

Facile synthesis of reduced graphene oxide-gold nanohybrid for potential use in industrial waste-water treatment

NASA Astrophysics Data System (ADS)

Kar, Prasenjit; Sardar, Samim; Liu, Bo; Sreemany, Monjoy; Lemmens, Peter; Ghosh, Srabanti; Pal, Samir Kumar

2016-01-01

Here, we report a facile approach, by the photochemical reduction technique, for in situ synthesis of Au-reduced graphene oxide (Au-RGO) nanohybrids, which demonstrate excellent adsorption capacities and recyclability for a broad range of dyes. High-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) data confirm the successful synthesis of Au-RGO nanohybrids. The effect of several experimental parameters (temperature and pH) variation can effectively control the dye adsorption capability. Furthermore, kinetic adsorption data reveal that the adsorption process follows a pseudo second-order model. The negative value of Gibbs free energy (ΔG0) confirms spontaneity while the positive enthalpy (ΔH0) indicates the endothermic nature of the adsorption process. Picosecond resolved fluorescence technique unravels the excited state dynamical processes of dye molecules adsorbed on the Au-RGO surface. Time resolved fluorescence quenching of Rh123 after adsorption on Au-RGO nanohybrids indicates efficient energy transfer from Rh123 to Au nanoparticles. A prototype device has been fabricated using Au-RGO nanohybrids on a syringe filter (pore size: 0.220 μm) and the experimental data indicate efficient removal of dyes from waste water with high recyclability. The application of this nanohybrid may lead to the development of an efficient reusable adsorbent in portable water purification.

Synthesis of modified sepiolite-g-polystyrene sulfonic acid nanohybrids by radiation induced graft polymerization

NASA Astrophysics Data System (ADS)

Taimur, Shaista; Hassan, Muhammad Inaam ul; Yasin, Tariq; Ali, Syed Wasim

2018-07-01

In this study, polystyrene (PS) grafted sepiolite nanohybrid (MS-g-PS) was synthesized by using simultaneous radiation grafting technique in the presence of dichloromethane (DCM) as solvent. The radiation grafting process was carried out under inert atmosphere at room temperature using gamma rays from a Co-60 irradiator. The degree of grafting was affected by absorbed dose and monomer concentration in the mixture. Sulfonation of synthesized nanohybrid was carried out with sulfuric acid. Both the grafting of styrene and its sulfonate derivative were verified by Fourier transform infrared spectroscopy (FT-IR). The structural and morphological investigations of these nanohybrids have been investigated by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The gravimetric investigations showed that grafting yield increases with the absorbed dose. Results showed that the system allows the controlled grafting of styrene onto sepiolite (Sep) in DCM.

A general route towards well-defined magneto- or fluorescent-plasmonic nanohybrids

NASA Astrophysics Data System (ADS)

Schmidtke, Christian; Kloust, Hauke; Bastús, Neus G.; Merkl, Jan-Philip; Tran, Huong; Flessau, Sandra; Feld, Artur; Schotten, Theo; Weller, Horst

2013-11-01

Herein, we present a general route towards defined nanohybrids, comprised of a fluorescent quantum dot (QD) or superparamagnetic iron oxide (Fe2O3) nanocrystal core and a tuneable corona of plasmonic gold or silver nanoparticles (NPs), adhered by a cross-linked poly(isoprene)-b-poly(ethylene glycol) diblock copolymer (PI-b-PEG) matrix. To this end, the PEG-terminus of the amphiphilic polymer was acylated with lipoic acid (LA), which, as is known, forms quasi-covalent Au-thiol- or Ag-thiol-bonds. Surprisingly, by variation of the ratio of the different NPs, inverse core/satellite structures bearing QDs or Fe2O3 around a metallic NP core were obtained. Furthermore, gold NPs or even closed gold shells were grown by in situ reductive deposition of Au3+ ions on Fe2O3 NP seeds. Finally, in order to demonstrate the scope of the method, ternary nanohybrids, composed of QDs, Fe2O3 and Au NPs, were accomplished. All magneto-plasmonic and fluorescent-plasmonic materials were thoroughly characterized by absorption and emission spectroscopy, TEM and TEM-EDX. Antibody conjugation to these novel nanohybrids proved their practical utility in a prototype immunoassay.Herein, we present a general route towards defined nanohybrids, comprised of a fluorescent quantum dot (QD) or superparamagnetic iron oxide (Fe2O3) nanocrystal core and a tuneable corona of plasmonic gold or silver nanoparticles (NPs), adhered by a cross-linked poly(isoprene)-b-poly(ethylene glycol) diblock copolymer (PI-b-PEG) matrix. To this end, the PEG-terminus of the amphiphilic polymer was acylated with lipoic acid (LA), which, as is known, forms quasi-covalent Au-thiol- or Ag-thiol-bonds. Surprisingly, by variation of the ratio of the different NPs, inverse core/satellite structures bearing QDs or Fe2O3 around a metallic NP core were obtained. Furthermore, gold NPs or even closed gold shells were grown by in situ reductive deposition of Au3+ ions on Fe2O3 NP seeds. Finally, in order to demonstrate the scope of

Comparison of drug delivery potentials of surface functionalized cobalt and zinc ferrite nanohybrids for curcumin in to MCF-7 breast cancer cells

NASA Astrophysics Data System (ADS)

Sawant, V. J.; Bamane, S. R.; Shejwal, R. V.; Patil, S. B.

2016-11-01

The functionalization and surface engineering of CoFe2O4 and ZnFe2O4 nanoparticles were performed by coating with PEG and Chitosan respectively using simple wet co-precipitation. Then multiactive therapeutic drug curcumin was loaded to form drug delivery nanohybrids by precipitation. These nanohybrids were characterized separately using UV-vis, FTIR, PL spectroscopy, XRD, VSM, SEM and TEM analysis. The moderate antibacterial activities of the nanohybrids were elaborated by in vitro antibacterial screening on Escherichia coli and Staphylococcus aureus. The anticancer potentials, apoptotic effects and enhanced drug delivery properties of these nanohybrids were confirmed and compared on MCF-7 cells by in vitro MTT assay. The drug delivery activities for hydrophobic drug and anticancer effects of chitosan coated zinc ferrite functionalized nanoparticles were higher than PEG coated cobalt ferrite nanohybrids.

Synthesis and controlled release properties of 2,4-dichlorophenoxy acetate-zinc layered hydroxide nanohybrid

NASA Astrophysics Data System (ADS)

Bashi, Abbas M.; Hussein, Mohd Zobir; Zainal, Zulkarnain; Tichit, Didier

2013-07-01

Direct reaction of ZnO with 2,4-dichlorophenoxyacetic acid (24D) solutions of different concentrations allows obtaining new organic-inorganic nanohybrid materials formed by intercalation of 24D into interlayers of zinc layered hydroxide (ZLH). XRD patterns show a progressive evolution of the structure as 24D concentration increases. The nanohybrid obtained at higher 24D concentration (24D-ZLH(0.4)) reveals a well ordered layered structure with two different basal spacings at 25.2 Å and 24 Å. The FTIR spectrum showing the vibrations bands of the functional groups of 24D and of the ZLH confirms the intercalation. SEM images are in agreement with the structural evolution observed by XRD and reveal the ribbon morphology of the nanohybrids. The release studies of 24D showed a rapid release of 94% for the first 100 min governed by the pseudo-second order kinetic model.

Fast detection of Listeria monocytogenes through a nanohybrid quantum dot complex.

PubMed

Donoso, Wendy; Castro, Ricardo I; Guzmán, Luis; López-Cabaña, Zoraya; Nachtigall, Fabiane M; Santos, Leonardo S

2017-09-01

Listeria monocytogenes is a recognized foodborne pathogen that causes listeriosis in susceptible consumers. Currently, the detection systems for Listeria in food detect live and dead bacteria, being the viable microorganisms most relevant for their ability to cause sickness in the population at risk. For this reason, a new nanohybrid compound was developed for the optical detection of Listeria that was based on polyamidoamine dendrimers functionalized with an auxotrophic cofactor (lipoic acid), together with the coupling of fluorescent semiconductor crystals (quantum dots). The nanohybrid sensor has a detection limit for viable L. monocytogenes of 5.19 × 10 3 colony-forming units per milliliter under epifluorescence microscopy. It was specific when used among other pathogens commonly found in food.

Preparation of magnetic photocatalyst nanohybrid decorated by polyoxometalate for the degradation of a pharmaceutical pollutant under solar light.

PubMed

Bastami, Tahereh Rohani; Ahmadpour, Ali

2016-05-01

Magnetic polyoxometalate nanohybrid was prepared by the surface modification of γ-Fe2O3/SrCO3 nanoparticles with PW 12 O 40 (3 -) polyoxometalate (POM) anions. The results of Fourier transform infrared (FTIR) and energy-dispersive X-ray (EDX) confirm the presence of POM on the surface of γ-Fe2O3/SrCO3 nanoparticles. TEM results revealed the ellipsoid-like structure of nanohybrid which was 23 nm in length and 6 nm in width. The activity of the photocatalyst was investigated by the photocatalytic degradation of ibuprofen (IBP) in an aqueous solution under solar light. It was found that in comparison with the γ-Fe2O3/SrCO3, the degradation of IBP after 2-h exposure to the solar light irradiation was significantly higher for POM-γ-Fe2O3/SrCO3 nanohybrids. The degradation of IBP was enhanced by the addition of H2O2 to the air saturated solution, while the addition of NaHCO3 and isopropanol restricted the degradation process. In the presence of H2O2, the Fenton photocatalyst degradation under solar light irradiation led to relatively complete degradation of IBP. Furthermore, the photocatalytic activity and magnetization properties of this magnetic photocatalyst nanohybrid provide a promising solution for the degradation of water pollutants and photocatalyst recovery. Graphical Abstract Schematic illustration for preparation of POM-γ-Fe2O3/SrCO3 nanohybrid and photocatalytic reaction of IBP on POM-γ-Fe2O3/SrCO3 nanohybrid.

Drug delivery system for an anticancer agent, chlorogenate-Zn/Al-layered double hydroxide nanohybrid synthesised using direct co-precipitation and ion exchange methods

NASA Astrophysics Data System (ADS)

Barahuie, Farahnaz; Hussein, Mohd Zobir; Arulselvan, Palanisamy; Fakurazi, Sharida; Zainal, Zulkarnain

2014-09-01

A nano-structured drug-inorganic clay hybrid involving an active anticancer compound, which is chlorogenic acid (CA) intercalated into Zn/Al-layered double hydroxide, has been assembled via ion-exchange and co-precipitation methods to form a nanohybrid CZAE (a chlorogenic acid-Zn/Al nanohybrid synthesised using an ion-exchange method) and CZAC (a chlorogenic acid-Zn/Al nanohybrid synthesised using a direct method), respectively. The X-ray diffraction (XRD) results confirmed that the CA-LDH had a hybrid structure in which the anionic chlorogenate is arranged between the interlayers as a horizontal monolayer at 90 and 20° angles from the x axis for CZAE and CZAC, respectively. Both nanohybrids have the properties of mesoporous materials. The high loading percentage of chlorogenic acid (approximately 43.2% for CZAE and 45.3% for CZAC) with basal spacings of 11.7 and 12.6 Å for CZAE and CZAC, respectively, corroborates the successful intercalation of chlorogenic acid into the interlayer gallery of layered double hydroxides. Free chlorogenic acid and the synthesised nanocomposites (CZAE, CZAC) were assessed for their cytotoxicity against various cancer cells. The Fourier transform infrared data supported the formation of both nanohybrids, and a thermal analysis showed that the nanohybrids are more thermally stable than their counterparts. The chlorogenate shows a sustained release, and the release rate of chlorogenate from CZAE and CZAC nanohybrids at pH 7.4 is remarkably lower than that at pH 4.8 due to their different release mechanisms. The release rate of chlorogenate from both nanohybrids can be described as pseudo-second order. The present investigation revealed the potential of the nanohybrids to enhance the in vitro anti-tumour effect of chlorogenic acid in liver and lung cancer cells in vitro.

Cr(VI) reduction and immobilization by novel carbonaceous modified magnetic Fe3O4/halloysite nanohybrid.

PubMed

Tian, Xike; Wang, Weiwei; Tian, Na; Zhou, Chaoxin; Yang, Chao; Komarneni, Sridhar

2016-05-15

In this work, a novel "Dumbbell-like" magnetic Fe3O4/Halloysite nanohybrid (Fe3O4/HNTs@C) with oxygen-containing organic group grafting on the surface of natural halloysite nanotubes (HNTs) and homogeneous Fe3O4 nanospheres selectively aggregating at the tips of modified halloysite nanotubes was successfully synthesized. XRD, TEM, IR spectroscopy, XPS and VSM were used to characterize this newly halloysite nanohybrid and its formation mechanism was discussed. Cr(VI) ions adsorption experiments showed that the Fe3O4/halloysite nanohybrid exhibited higher adsorption ability with a maximum adsorption capacity of 132 mg/L at 303K, which is about 100 times higher than that of unmodified halloysite nanotubes. More importantly, with the reduction of Fe3O4 and electron-donor effect of oxygen-containing organic groups, Cr(VI) ions were easily reduced into low toxicity Cr(III) and then adsorbed onto the surface of halloysite nanohybrid. In addition, appreciable magnetization was observed due to the aggregation of magnetite nanoparticles, which make adsorbent facility separated from aqueous solutions after Cr pollution adsorption. Copyright © 2016 Elsevier B.V. All rights reserved.

Intensification of electrochemiluminescence of luminol on TiO2 supported Au atomic cluster nano-hybrid modified electrode.

PubMed

Yu, Zhimin; Wei, Xiuhua; Yan, Jilin; Tu, Yifeng

2012-04-21

With TiO(2) nanoparticles as carrier, a supported nano-material of Au atomic cluster/TiO(2) nano-hybrid was synthesized. It was then modified onto the surface of indium tin oxide (ITO) by Nafion to act as a working electrode for exciting the electrochemiluminescence (ECL) of luminol. The properties of the nano-hybrid and the modified electrode were characterized by XRD, XPS, electronic microscopy, electrochemistry and spectroscopy. The experimental results demonstrated that the modification of this nano-hybrid onto the ITO electrode efficiently intensified the ECL of luminol. It was also revealed that the ECL intensity of luminol on this modified electrode showed very sensitive responses to oxygen and hydrogen peroxide. The detection limits for dissolved oxygen and hydrogen peroxide were 2 μg L(-1) and 5.5 × 10(-12) M, respectively. Besides the discussion of the intensifying mechanism of this nano-hybrid for ECL of luminol, the developed method was also applied for monitoring dissolved oxygen and evaluating the scavenging efficiency of reactive oxygen species of the Ganoderma lucidum spore.

Graphene and Carbon-Nanotube Nanohybrids Covalently Functionalized by Porphyrins and Phthalocyanines for Optoelectronic Properties.

PubMed

Wang, Aijian; Ye, Jun; Humphrey, Mark G; Zhang, Chi

2018-04-01

In recent years, there has been a rapid growth in studies of the optoelectronic properties of graphene, carbon nanotubes (CNTs), and their derivatives. The chemical functionalization of graphene and CNTs is a key requirement for the development of this field, but it remains a significant challenge. The focus here is on recent advances in constructing nanohybrids of graphene or CNTs covalently linked to porphyrins or phthalocyanines, as well as their application in nonlinear optics. Following a summary of the syntheses of nanohybrids constructed from graphene or CNTs and porphyrins or phthalocyanines, explicit intraconjugate electronic interactions between photoexcited porphyrins/phthalocyanines and graphene/CNTs are introduced classified by energy transfer, electron transfer, and charge transfer, and their optoelectronic applications are also highlighted. The major current challenges for the development of covalently linked nanohybrids of porphyrins or phthalocyanines and carbon nanostructures are also presented. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Detection of alprazolam with a lab on paper economical device integrated with urchin like Ag@ Pd shell nano-hybrids.

PubMed

Narang, Jagriti; Malhotra, Nitesh; Singhal, Chaitali; Mathur, Ashish; Pn, Anoop Krishna; Pundir, C S

2017-11-01

We present results of the studies relating to fabrication of a microfluidic biosensor chip based on urchin like Ag@ Pd shell nano-hybrids that is capable of sensing alprazolam through electrochemical detection. Using this chip we demonstrate, with high reliability and in a time efficient manner, the detection of alprazolam present in buffer solutions at clinically relevant concentrations. Methylene blue (MB) was also doped as redox transition substance for sensing alprazolam. Nano-hybrids modified EμPAD showed wide linear range 1-300ng/ml and low detection limit of 0.025ng/l. Low detection limit can further enhance its suitability for forensic application. Nano-hybrids modified EμPAD was also employed for determination of drug in real samples such as human urine. Reported facile lab paper approach integrated with urchin like Ag@ Pd shell nano-hybrids could be well applied for the determination of serum metabolites. Copyright © 2016 Elsevier B.V. All rights reserved.

Effect of Laser-assisted and Conventional In-office Bleaching on Monomer Release from Microhybrid and Nanohybrid Composite.

PubMed

Omrani, Ladan Ranjbar; Farjadfar, Shayan; Pedram, Parham; Sadray, Sima; Kamangar, Sedighe Sadat Hashemi; Chiniforoush, Nasim

2017-06-30

Bleaching might affect structural properties of composite materials, and lead to monomer release. This study aimed to evaluate the effect of Laser-assisted and conventional in-office bleaching on the release of BIS-GMA, TEGDMA, and UDMA monomers from a nanohybrid and a microhybrid BIS-GMA based composite. 32 samples of each composite, were divided into 4 subgroups; subgroup 1: Conventional in-office bleaching (CIB) with the Opalescence Boost PF 38% gel, subgroup 2: Laser-assisted bleaching (LBO) with the Opalescence Boost PF 38% gel, subgroup 3: Laser-assisted bleaching (LBH) with the JW Power bleaching gel, subgroup 4: (CO) control without bleaching. All the samples were immersed in tubes of 2cc Ethanol 75% medium. The released monomers were analyzed using the high performance liquid chromatography (HPLC) method 24 h, 7, and 28 days. Data's were analyzed by Univariate Analysis of Variance test followed by Tukeys HSD. The amount of TEGDMA monomer released was not significant. However, nanohybrid composites showed significantly more monomer release than microhybrid composites (P < 0.05). For UDMA the interaction was significant only after 1 week. In microhybrid composites, the CO subgroup showed more monomer release than LBH and LBO. In nanohybrid composites, LBH showed more monomer release than CIB and CO subgroups. For BIS-GMA monomers the interaction was significant at all time periods and the LBH subgroup of nanohybrid composite had significantly more BIS_GMA release in comparison to other subgroups. Bleaching by laser with JW Power Bleaching gel led to more monomer release in nanohybrid composite.

An effective approach to study the biocompatibility of Fe3O4 nanoparticles, graphene and their nanohybrid composite

NASA Astrophysics Data System (ADS)

Singh, Ashwani Kumar; Singh, Pallavi; Verma, Rajiv Kumar; Yadav, Suresh; Singh, Kedar; Srivastava, Amit

2018-02-01

The present manuscript describes a simple, facile and effective solvothermal route to synthesize Fe3O4 nanoparticles (Fe3O4 NPs), reduced graphene oxide nanosheets (rGO NSs) and Fe3O4/reduced graphene oxide nanohybrid composite (Fe3O4/rGO nanohybrid composite) and subsequently examines their comparative biocompatibilities. The as-obtained Fe3O4 NPs, rGO NSs and Fe3O4/rGO nanohybrid composite have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. The XRD studies and scanning electron microscope confirmed the proper phase formation and the surface morphology of the as-synthesized products, respectively. The Raman spectra of Fe3O4 NPs show the strongest peak at 673 cm-1 which can be assigned to A1g peak of bare Fe3O4 NPs and it complements the XRD studies. Furthermore, the increment in the I D/I G ratio in the Fe3O4/rGO nanohybrid composite suggests the creation of defects in graphene sheets due to strain caused by Fe3O4 NPs. The biocompatibility of these samples has been tested using Lung cancer cell line H1299 through MTT assay. The MTT assay reveals that the nanohybrid composite endows more biocompatible and effectiveness than rGO NSs and Fe3O4 NPs individually, as anti-proliferative agent for cancer treatment.

Synthesis and characterization of β-Ni(OH)2 embedded with MgO and ZnO nanoparticles as nanohybrids for energy storage devices

NASA Astrophysics Data System (ADS)

Kumar, C. R. Ravi; Santosh, M. S.; Nagaswarupa, H. P.; Prashantha, S. C.; Yallappa, S.; Kumar, M. R. Anil

2017-06-01

In this study, the electrode material (nickel hydroxide powder) has been synthesized by a co-precipitation method using sodium hydroxide and nickel sulphate as precipitator and nickel source, respectively. The obtained nickel hydroxide powder has been subsequently embedded with biosynthesized MgO and ZnO nanoparticles as nanohybrids, which have been investigated as a novel hybrid electrode material for power-storage applications. The powder x-ray diffraction pattern of nickel hydroxide (Ni(OH)2)-based nanohybrid materials reveals a typical β-phase. Fourier transform infrared spectroscopy confirms the embedded structures of nanohybrids and thermal stability by thermogravimetry and differential thermal) analysis. The electrochemical properties of these materials have been studied using cyclic voltammetry and electrochemical impedance spectroscopy (EIS). The specific capacitance values are found to be 439, 1076, and 622 F g-1 for bare β-Ni(OH)2, and for β-Ni(OH)2 embedded with ZnO and MgO nanohybrids, respectively, at a scan rate of 10 mVs-1. The enhanced capacitance of nanohybrids is also evident from EIS measurements. Galvanostatic charge-discharge tests for these designed nanohybrids show excellent capacitance performance in battery and supercapacitor applications. These innovative results could be considered for the expansion of novel resources to scale for power-storage applications and may contribute to the development of this niche area at large.

Nanohybrid conjugated polyelectrolytes: highly photostable and ultrabright nanoparticles

NASA Astrophysics Data System (ADS)

Darwish, Ghinwa H.; Karam, Pierre

2015-09-01

We present a general and straightforward one-step approach to enhance the photophysical properties of conjugated polyelectrolytes. Upon complexation with an amphiphilic polymer (polyvinylpyrrolidone), an anionic conjugated polyelectrolyte (poly[5-methoxy-2-(3-sulfopropoxy)-1,4-phenylenevinylene]) was prepared into small nanoparticles with exceptional photostability and brightness. The polymer fluorescence intensity was enhanced by 23 -fold and could be easily tuned by changing the order of addition. Single molecule experiments revealed a complete suppression of blinking. In addition, after only losing 18% of the original intensity, a remarkable amount of photons were emitted per particle (~109, on average). This number is many folds greater than popular organic fluorescent dyes. We believe that an intimate contact between the two polymers is shielding the conjugated polyelectrolyte from the destructive photooxidation. The prepared nanohybrid particles will prove instrumental in single particle based fluorescent assays and can serve as a probe for the current state-of-the-art bioimaging fluorescence techniques.We present a general and straightforward one-step approach to enhance the photophysical properties of conjugated polyelectrolytes. Upon complexation with an amphiphilic polymer (polyvinylpyrrolidone), an anionic conjugated polyelectrolyte (poly[5-methoxy-2-(3-sulfopropoxy)-1,4-phenylenevinylene]) was prepared into small nanoparticles with exceptional photostability and brightness. The polymer fluorescence intensity was enhanced by 23 -fold and could be easily tuned by changing the order of addition. Single molecule experiments revealed a complete suppression of blinking. In addition, after only losing 18% of the original intensity, a remarkable amount of photons were emitted per particle (~109, on average). This number is many folds greater than popular organic fluorescent dyes. We believe that an intimate contact between the two polymers is shielding the

Pt nanoparticle-reduced graphene oxide nanohybrid for proton exchange membrane fuel cells.

PubMed

Park, Dae-Hwan; Jeon, Yukwon; Ok, Jinhee; Park, Jooil; Yoon, Seong-Ho; Choy, Jin-Ho; Shul, Yong-Gun

2012-07-01

A platinum nanoparticle-reduced graphene oxide (Pt-RGO) nanohybrid for proton exchange membrane fuel cell (PEMFC) application was successfully prepared. The Pt nanoparticles (Pt NPs) were deposited onto chemically converted graphene nanosheets via ethylene glycol (EG) reduction. According to the powder X-ray diffraction (XRD) pattern and transmission electron microscopy (TEM) analysis, the face-centered cubic Pt NPs (3-5 nm in diameter) were homogeneously dispersed on the RGO nanosheets. The electrochemically active surface area and PEMFC power density of the Pt-RGO nanohybrid were determined to be 33.26 m2/g and 480 mW/cm2 (maximum values), respectively, at 75 degrees C and at a relative humidity (RH) of 100% in a single-cell test experiment.

One year comparative clinical evaluation of EQUIA with resin-modified glass ionomer and a nanohybrid composite in noncarious cervical lesions

PubMed Central

Vaid, Deepa Sunil; Shah, Nimisha Chinmay; Bilgi, Priyanka Shripad

2015-01-01

Aims: Comparative evaluation of EQUIA with a resin-modified glass ionomer cement (RMGIC; GC Gold Label glass ionomer light cured universal restorative cement) and a nanohybrid composite (Tetric N-Ceram) in noncarious cervical lesions (NCCLs). Background: To establish the most suitable material for the restoration of NCCLs. Settings and Design: In vivo study. Materials and Methods: Eighty-seven NCCLs were randomly restored with EQUIA, a RMGIC, and a nanohybrid composite. Clinical evaluation of the restorations was done following the Unites States Public Health criteria by a single-blinded investigator. Data were formulated, and statistical analysis was done by Chi-square test. Statistical Analysis Used: Chi-square test. Results: No significant difference was found between EQUIA, RMGIC, and nanohybrid composite at 1-month, at 6 months, and at 1-year (P > 0.05). Conclusions: EQUIA, resin-modified glass ionomer, and nanohybrid composite performed equally at 1-month, 6 months, and 1-year follow-up periods. PMID:26752837

Synthesis and characterization of MnS2/reduced graphene oxide nanohybrids for with photocatalytic and antibacterial activity.

PubMed

Fakhri, Ali; Kahi, Delaram Salehpour

2017-01-01

A facile one-step hydrothermal route was developed here to prepare MnS 2 /reduced graphene oxide nanohybrids. The crystal morphologies could be controlled by adjusting the solvent, surfactant, and pH of the precursor solution. X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), UV-Vis absorption spectra, and photoluminescence spectra (PL), were used to characterize the structures of the samples were used to characterize the structures of the samples, and the specific surface area was determined using the Brunauer-Emmett-Teller (BET) method. The thickness of the MnS 2 nanoparticles and MnS 2 /reduced graphene oxide nanohybrids were measured to be about 20 and 5nm, respectively. The total pore volume and specific surface area were 0.540 and 1.173cm 3 g -1 and 45.91 and 98.23m 2 g -1 for pure MnS 2 and MnS 2 /r-GO hybrids, respectively. Carbophenothion as an insecticide photodegradation was used to estimate the photocatalytic activity of the MnS 2 /reduced graphene oxide nanohybrids morphologies under UV light. The Carbophenothion hardly decomposed during photolysis over a period of 45min. The rate constant, k value, for the photocatalysis of Carbophenothion by MnS 2 /reduced graphene oxide nanohybrids under UV light radiation is 0.134min -1 . The antibacterial properties of the nanohybrids were evaluated by determining their minimum inhibitory and bactericidal concentrations (MIC and MBC), using a broth microdilution assay for Escherichia coli (E. coli) bacteria. The MIC and MBC values are 4.0 and 32.0μg/mL. Copyright © 2016 Elsevier B.V. All rights reserved.

Relative biocompatibility of micro-hybrid and nano-hybrid light-activated composite resins.

PubMed

Olabisi Arigbede, Abiodun; Folasade Adeyemi, Bukola; Femi-Akinlosotu, Omowumi

2017-01-01

Background. In vitro studies have revealed a direct association between resin content and cytotoxicity of composite resins; however, implantation studies in this regard are sparse. This study investigates the relationship between filler content of composite resins and biocompatibility. Methods. This research employed twelve 180‒200-gr male Wistar rats, 1 nano-hybrid (Prime-Dent Inc.) and 1 micro-hybrid (Medental Inc.) composite resins containing 74% and 80‒90% filler content, respectively. The samples were assessed on the 2nd, 14th and 90th day of implantation. Four rats were allocated to each day in this experimental study. A section of 1.5mm long cured nano-hybrid and micro-hybrid materials were implanted into the right and left upper and lower limbs of the rats, respectively. Eight samples were generated on each day of observation. Inflammation was graded according to the criteria suggested by Orstavik and Major. Pearson's chi-squared test was employed to determine the relationship between the tissue responses of the two materials. Statistical significance was set at P < 0.05. Results . The average grade of inflammation for the nano-hybrid on the 2nd day of implantation was 3.3. The micro-hybrid resin had a score of 3.0 for cellular inflammation. On the 14th day, the micro-hybrid resin also exhibited a lower average grade for cellular inflammation. On the 90th day, the micro-hybrid resin had a higher grade of inflammation (0.9) compared to 0.3 recorded for nano-hybrid. The composite resins with higher filler content elicited a significantly lower grade of inflammation irrespective of the duration (χ=20.000, df=8, P=0.010) while the composite resins with lower filler content elicited a significantly lower inflammatory response on the 90th day (χ=4.000, df=1, P=0.046). Conclusion. The composite resins with higher filler content generally elicited significantly lower grades of inflammation, and the composite resins with lower filler content exhibited

Relative biocompatibility of micro-hybrid and nano-hybrid light-activated composite resins

PubMed Central

Olabisi Arigbede, Abiodun; Folasade Adeyemi, Bukola; Femi-Akinlosotu, Omowumi

2017-01-01

Background. In vitro studies have revealed a direct association between resin content and cytotoxicity of composite resins; however, implantation studies in this regard are sparse. This study investigates the relationship between filler content of composite resins and biocompatibility. Methods. This research employed twelve 180‒200-gr male Wistar rats, 1 nano-hybrid (Prime-Dent Inc.) and 1 micro-hybrid (Medental Inc.) composite resins containing 74% and 80‒90% filler content, respectively. The samples were assessed on the 2nd, 14th and 90th day of implantation. Four rats were allocated to each day in this experimental study. A section of 1.5mm long cured nano-hybrid and micro-hybrid materials were implanted into the right and left upper and lower limbs of the rats, respectively. Eight samples were generated on each day of observation. Inflammation was graded according to the criteria suggested by Orstavik and Major. Pearson’s chi-squared test was employed to determine the relationship between the tissue responses of the two materials. Statistical significance was set at P < 0.05. Results. The average grade of inflammation for the nano-hybrid on the 2nd day of implantation was 3.3. The micro-hybrid resin had a score of 3.0 for cellular inflammation. On the 14th day, the micro-hybrid resin also exhibited a lower average grade for cellular inflammation. On the 90th day, the micro-hybrid resin had a higher grade of inflammation (0.9) compared to 0.3 recorded for nano-hybrid. The composite resins with higher filler content elicited a significantly lower grade of inflammation irrespective of the duration (χ=20.000, df=8, P=0.010) while the composite resins with lower filler content elicited a significantly lower inflammatory response on the 90th day (χ=4.000, df=1, P=0.046). Conclusion. The composite resins with higher filler content generally elicited significantly lower grades of inflammation, and the composite resins with lower filler content exhibited

Preparation and characterization of an anti-inflammatory agent based on a zinc-layered hydroxide-salicylate nanohybrid and its effect on viability of Vero-3 cells

PubMed Central

Ramli, Munirah; Hussein, Mohd Zobir; Yusoff, Khatijah

2013-01-01

A new organic-inorganic nanohybrid based on zinc-layered hydroxide intercalated with an anti-inflammatory agent was synthesized through direct reaction of salicylic acid at various concentrations with commercially available zinc oxide. The basal spacing of the pure phase nanohybrid was 15.73 Å, with the salicylate anions arranged in a monolayer form and an angle of 57 degrees between the zinc-layered hydroxide interlayers. Fourier transform infrared study further confirmed intercalation of salicylate into the interlayers of zinc-layered hydroxide. The loading of salicylate in the nanohybrid was estimated to be around 29.66%, and the nanohybrid exhibited the properties of a mesoporous-type material, with greatly enhanced thermal stability of the salicylate compared with its free counterpart. In vitro cytotoxicity assay revealed that free salicylic acid, pure zinc oxide, and the nanohybrid have a mild effect on viability of African green monkey kidney (Vero-3) cells. PMID:23345976

Improving the physical properties of starch using a new kind of water dispersible nano-hybrid reinforcement.

PubMed

Morales, Noé J; Candal, Roberto; Famá, Lucía; Goyanes, Silvia; Rubiolo, Gerardo H

2015-08-20

Plasticized cassava starch matrix composites reinforced by a multi-wall carbon nanotube (MWCNT)-hercynite (FeAl2O4) nanomaterial were developed. The hybrid nanomaterial consists of FeAl2O4 nanoparticles anchored strongly to the surface of the MWCNT. This nano-hybrid filler shows an irregular geometry, which provides a strong mechanical interlocking with the matrix, and excellent stability in water, ensuring a good dispersion in the starch matrix. The composite containing 0.04wt.% of the nano-hybrid filler displays increments of 370% in the Young's modulus, 138% in tensile strength and 350% in tensile toughness and a 70% decrease in water vapor permeability relative to the matrix material. All of these significant improvements are explained in terms of the nano-hybrid filler homogenous dispersion and its high affinity with both plasticizers, glycerol and water, which induces crystallization without deterioration of the tensile toughness. Copyright © 2015 Elsevier Ltd. All rights reserved.

Rhodium Nanoparticle-mesoporous Silicon Nanowire Nanohybrids for Hydrogen Peroxide Detection with High Selectivity

PubMed Central

Song, Zhiqian; Chang, Hucheng; Zhu, Weiqin; Xu, Chenlong; Feng, Xinjian

2015-01-01

Developing nanostructured electrocatalysts, with low overpotential, high selectivity and activity has fundamental and technical importance in many fields. We report here rhodium nanoparticle and mesoporous silicon nanowire (RhNP@mSiNW) hybrids for hydrogen peroxide (H2O2) detection with high electrocatalytic activity and selectivity. By employing electrodes that loaded with RhNP@mSiNW nanohybrids, interference caused from both many electroactive substances and dissolved oxygen were eliminated by electrochemical assaying at an optimal potential of +75 mV. Furthermore, the electrodes exhibited a high detection sensitivity of 0.53 μA/mM and fast response (< 5 s). This high-performance nanohybrid electrocatalyst has great potential for future practical application in various oxidase-base biosensors. PMID:25588953

The role of ionic electrolytes on capacitive performance of ZnO-reduced graphene oxide nanohybrids with thermally tunable morphologies.

PubMed

Prakash, Anand; Bahadur, D

2014-02-12

In the present work, the role of the reaction temperatures on the morphologies of zinc oxide-reduced graphene oxide (ZnO-RGO) nanohybrids and their supercapacitive performance in two different aqueous electrolytes (1.0 M KCl and Na2SO4) were investigated. The ZnO-RGO nanohybrids were synthesized at two different temperatures (ca. 95 and 145 °C) by solvothermal method and labeled as ZnO-RGO-1 and ZnO-RGO-2, respectively. The structure and composition of ZnO-RGO nanohybrids were confirmed by means of X-ray diffraction, electron microscopes (scanning and transmission), X-ray photoelectron, photoluminescence, and Raman spectroscopy. These results show that the temperature allows a good control on loading and morphology of ZnO nanoassemblies in ZnO-RGO nanohybrids and at elevated temperature of 145 °C, ZnO nanoassemblies break and get completely embedded into RGO matrices. The electrochemical performance of ZnO-RGO nanohybrids was examined by cyclic voltammograms (CVs), galvanostatic charge-discharge (chronopotentiometry) and electrochemical impedance spectroscopy (EIS) in 1.0 M KCl and Na2SO4 aqueous electrolytes respectively. Combining the EIS and zeta potential behavior, a direct link between the charge transfer resistance and electrical double layers is established which is responsible for excellent capacitive performance of ZnO-RGO-2. The ZnO-RGO-2 displays high specific capacitance (107.9 F/g, scan rate = 50 mVs(-1)) in 1.0 M KCl and exhibits merely 4.2% decay in specific capacitance values over 200 cycles.

Do Nanofilled/Nanohybrid Composites Allow for Better Clinical Performance of Direct Restorations Than Traditional Microhybrid Composites? A Systematic Review.

PubMed

Angerame, D; De Biasi, M

2018-03-23

This systematic review was carried out to assess the clinical effectiveness of nanofilled and nanohybrid composites used for direct restorations in comparison with microhybrid composites. The guidelines for the preferred reporting items for systematic reviews and meta-analyses were followed. A search of articles published from July 1996 to February 2017 was performed in PubMed, SciVerse Scopus, Latin American and Caribbean Health Sciences, the Scientific Electronic Library Online, and the Cochrane Library. The present review selected only randomized controlled trials comparing the clinical performance of a nanofilled or nanohybrid composite for direct restorations with that of a microhybrid composite. The research found 201 studies. Twenty-one articles fulfilled the criteria of the present review. However, the included studies were characterized by great methodological diversities. As a general trend, nanofilled and nanohybrid composites were found to be capable of clinical performance, marginal quality, and resistance to wear similar to that of traditional composites without showing improved surface characteristics. The risk of bias of included studies was judged unclear or high. The clinical performance of nanofilled/nanohybrid composites was found to be comparable to that of traditional composites in the posterior area. The data concerning anterior and cervical restorations were insufficient. With regard to the esthetic properties, there is a compelling need for studies on anterior teeth in which the operators are kept unaware of the restorative material. Nanofilled/nanohybrid composites seem to be a valid alternative to traditional microhybrid composites, and at the moment, there is low-level evidence attesting a lack of their superiority.

The role of reduced graphene oxide on the electrochemical activity of MFe2O4 (M = Fe, Co, Ni and Zn) nanohybrids

NASA Astrophysics Data System (ADS)

Suresh, Shravan; Prakash, Anand; Bahadur, D.

2018-02-01

In this work, a comparative study of electrochemical performance of reduced graphene oxide-ferrites (RGO-MFe2O4, M = Fe, Co, Ni, and Zn) nanohybrids synthesized by hydrothermal method was done. The structural morphology and investigation of other physical properties of nanohybrids confirm the cubic spinel phase of the MFe2O4, reduction of graphene oxide and the distribution of ferrite nanoparticles (NPs) on RGO nanosheets. The role of RGO on the electrochemical behavior of nanohybrids was understood by quantifying the charge storage capacitance and charging-discharging behavior in a 0.1 M Na2SO4 electrolyte. The specific capacitance values of pristine Fe3O4, CoFe2O4, NiFe2O4, and ZnFe2O4 are 128, 117, 15.2 and 9.1 F g-1 respectively whereas specific capacitance of RGO-Fe3O4, RGO-CoFe2O4, RGO-NiFe2O4 and RGO-ZnFe2O4 are 233, 200, 25 and 66.8 F g-1 respectively. Our investigation suggests that apart from specific surface area of nanohybrids other factors such as structural morphology determine interaction between nanohybrids and electrolyte ions which play critical role in elevating the performance of electrodes.

Discriminative sensing of DOPA enantiomers by cyclodextrin anchored graphene nanohybrids.

PubMed

Ates, Salih; Zor, Erhan; Akin, Ilker; Bingol, Haluk; Alpaydin, Sabri; Akgemci, Emine G

2017-06-01

Discriminative sensing of chiral species with a convenient and robust system is a challenge in chemistry, pharmaceutics and particularly in biomedical science. Advanced nanohybrid materials for discrimination of these biologically active molecules can be developed by combination of individual obvious advantages of different molecular scaffolds. Herein, we report on the comparison of the performance of cyclodextrin functionalized graphene derivatives (x-CD/rGO, x: α-, β-, γ-) for discrimination of DOPA enantiomers. Within this respect, electrochemical measurements were conducted and the experimental results were compared to molecular docking method. Thanks to cavity size of γ-CD and the unique properties of graphene, rGO/γ-CD nanohybrid is capable of selective recognition of DOPA enantiomers. Limit of detection (LOD) value and sensitivity were determined as 15.9 μM and 0.2525 μA μM -1 for D-DOPA, and 14.9 μM and 0.6894 μA μM -1 for L-DOPA. Copyright © 2017 Elsevier B.V. All rights reserved.

Can magneto-plasmonic nanohybrids efficiently combine photothermia with magnetic hyperthermia?

NASA Astrophysics Data System (ADS)

Espinosa, Ana; Bugnet, Mathieu; Radtke, Guillaume; Neveu, Sophie; Botton, Gianluigi A.; Wilhelm, Claire; Abou-Hassan, Ali

2015-11-01

Multifunctional hybrid-design nanomaterials appear to be a promising route to meet the current therapeutics needs required for efficient cancer treatment. Herein, two efficient heat nano-generators were combined into a multifunctional single nanohybrid (a multi-core iron oxide nanoparticle optimized for magnetic hyperthermia, and a gold branched shell with tunable plasmonic properties in the NIR region, for photothermal therapy) which impressively enhanced heat generation, in suspension or in vivo in tumours, opening up exciting new therapeutic perspectives.Multifunctional hybrid-design nanomaterials appear to be a promising route to meet the current therapeutics needs required for efficient cancer treatment. Herein, two efficient heat nano-generators were combined into a multifunctional single nanohybrid (a multi-core iron oxide nanoparticle optimized for magnetic hyperthermia, and a gold branched shell with tunable plasmonic properties in the NIR region, for photothermal therapy) which impressively enhanced heat generation, in suspension or in vivo in tumours, opening up exciting new therapeutic perspectives. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr06168g

Carbon nanotubes@silicon dioxide nanohybrids coating for solid-phase microextraction of organophosphorus pesticides followed by gas chromatography-corona discharge ion mobility spectrometric detection.

PubMed

Saraji, Mohammad; Jafari, Mohammad Taghi; Mossaddegh, Mehdi

2016-01-15

A high efficiency solid-phase microextraction (SPME) fiber coated with porous carbon nanotubes-silicon dioxide (CNTs-SiO2) nanohybrids was synthesized and applied for the determination of some organophosphorus pesticides (OPPs) in vegetables, fruits and water samples. Gas chromatography-corona discharge ion mobility spectrometry was used as the detection system. Glucose, as a biocompatible compound, was used for connecting CNT and SiO2 during a hydrothermal process. The electrospinning technique was also applied for the fiber preparation. The parameters affecting the efficiency of extraction, including stirring rate, salt effect, extraction temperature, extraction time, desorption temperature and desorption time, were investigated and optimized. The developed CNTs@SiO2 fiber presented better extraction efficiency than the commercial SPME fibers (PA, PDMS, and PDMS-DVB). The intra- and inter-day relative standard deviations were found to be lower than 6.2 and 9.0%, respectively. For water samples, the limits of detection were in the range of 0.005-0.020 μg L(-1) and the limits of quantification were between 0.010 and 0.050 μg L(-1). The results showed a good linearity in the range of 0.01-3.0 μg L(-1) for the analytes. The spiking recoveries ranged from 79 (± 9) to 99 (± 8). The method was successfully applied for the determination of OPPs in real samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Thermal Degradation Studies of Polyurethane/POSS Nanohybrid Elastomers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lewicki, J P; Pielichowski, K; TremblotDeLaCroix, P

2010-03-05

Reported here is the synthesis of a series of Polyurethane/POSS nanohybrid elastomers, the characterization of their thermal stability and degradation behavior at elevated temperatures using a combination of Thermal Gravimetric Analysis (TGA) and Thermal Volatilization Analysis (TVA). A series of PU elastomers systems have been formulated incorporating varying levels of 1,2-propanediol-heptaisobutyl-POSS (PHIPOSS) as a chain extender unit, replacing butane diol. The bulk thermal stability of the nanohybrid systems has been characterized using TGA. Results indicate that covalent incorporation of POSS into the PU elastomer network increase the non-oxidative thermal stability of the systems. TVA analysis of the thermal degradation ofmore » the POSS/PU hybrid elastomers have demonstrated that the hybrid systems are indeed more thermally stable when compared to the unmodified PU matrix; evolving significantly reduced levels of volatile degradation products and exhibiting a {approx}30 C increase in onset degradation temperature. Furthermore, characterization of the distribution of degradation products from both unmodified and hybrid systems indicate that the inclusion of POSS in the PU network is directly influencing the degradation pathways of both the soft and hard block components of the elastomers: The POSS/PU hybrid systems show reduced levels of CO, CO2, water and increased levels of THF as products of thermal degradation.« less

Thermal decomposition pathway of undoped and doped zinc layered gallate nanohybrid with Fe 3+, Co 2+ and Ni 2+ to produce mesoporous and high pore volume carbon material

NASA Astrophysics Data System (ADS)

Ghotbi, Mohammad Yeganeh; bin Hussein, Mohd Zobir; Yahaya, Asmah Hj; Abd Rahman, Mohd Zaki

2009-12-01

A series of brucite-like materials, undoped and doped zinc layered hydroxide nitrate with 2% (molar) Fe 3+, Co 2+ and Ni 2+ were synthesized. Organic-inorganic nanohybrid material with gallate anion as a guest, and zinc hydroxide nitrate, as an inorganic layered host was prepared by the ion-exchange method. The nanohybrid materials were heat-treated at various temperatures, 400-700 °C. X-ray diffraction, thermal analysis and also Fourier transform infrared results showed that incorporation of the doping agents within the zinc layered hydroxide salt layers has enhanced the heat-resistivity of the nanohybrid materials in the thermal decomposition pathway. Porous carbon materials can be obtained from the heat-treating the nanohybrids at 600 and 700 °C. Calcination of the nanohybrids at 700 °C under nitrogen atmosphere produces mesoporous and high pore volume carbon materials.

High-temperature chemical and microstructural transformations of an organic-inorganic nanohybrid captopril intercalated Mg-Al layered double hydroxide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang Hui; Guo Shaohuan; Zou Kang

The thermal evolution of a crystalline organic-inorganic nanohybrid captopril intercalated Mg-Al layered double hydroxide (LDH) [Mg{sub 0.68}Al{sub 0.32}(OH){sub 2}] (C{sub 9}H{sub 13}NO{sub 3}S){sub 0.130}(CO{sub 3}){sub 0.030}.0.53H{sub 2}O obtained by coprecipitation method is studied based upon in situ high-temperature X-ray diffraction, in situ infrared and thermogravimetric analysis coupled with mass spectroscopy analysis. The results reveal that a metastable quasi-interstratified layered nanohybrid involving carbonate-LDH and reoriented less ordered captopril-LDH was firstly observed as captopril-LDH heat-treated between 140 and 230 deg. C. The major decomposition/combustion of interlayer organics occur between 270 and 550 deg. C. A schematic model on chemical and microstructural evolutionmore » of this particular drug-inorganic nanohybrid upon heating in air atmosphere is proposed.« less

Ultrasonic-electrodeposition of PtPd alloy nanoparticles on ionic liquid-functionalized graphene paper: towards a flexible and versatile nanohybrid electrode

NASA Astrophysics Data System (ADS)

Sun, Yimin; Zheng, Huaming; Wang, Chenxu; Yang, Mengmeng; Zhou, Aijun; Duan, Hongwei

2016-01-01

Here we fabricate a new type of flexible and versatile nanohybrid paper electrode by ultrasonic-electrodeposition of PtPd alloy nanoparticles on freestanding ionic liquid (IL)-functionalized graphene paper, and explore its multifunctional applications in electrochemical catalysis and sensing systems. The graphene-based paper materials demonstrate intrinsic flexibility, exceptional mechanical strength and high electrical conductivity, and therefore can serve as an ideal freestanding flexible electrode for electrochemical devices. Furthermore, the functionalization of graphene with IL (i.e., 1-butyl-3-methylimidazolium tetrafluoroborate) not only increases the electroactive surface area of a graphene-based nanohybrid paper electrode, but also improves the adhesion and dispersion of metal nanoparticles on the paper surface. These unique attributes, combined with the merits of an ultrasonic-electrodeposition method, lead to the formation of PtPd alloy nanoparticles on IL-graphene paper with high loading, uniform distribution, controlled morphology and favourable size. Consequently, the resultant nanohybrid paper electrode exhibits remarkable catalytic activity as well as excellent cycle stability and improved anti-poisoning ability towards electrooxidation of fuel molecules such as methanol and ethanol. Furthermore, for nonenzymatic electrochemical sensing of some specific biomarkers such as glucose and reactive oxygen species, the nanohybrid paper electrode shows high selectivity, sensitivity and biocompatibility in these bio-catalytic processes, and can be used for real-time tracking hydrogen peroxide secretion by living human cells. All these features demonstrate its promising application as a versatile nanohybrid electrode material in flexible and lightweight electrochemical energy conversion and biosensing systems such as bendable on-chip power sources, wearable/implantable detectors and in vivo micro-biosensors.Here we fabricate a new type of flexible and

Two-year clinical comparison of a flowable-type nano-hybrid composite and a paste-type composite in posterior restoration.

PubMed

Hirata-Tsuchiya, Shizu; Yoshii, Shinji; Ichimaru-Suematsu, Miki; Washio, Ayako; Saito, Noriko; Urata, Mariko; Hanada, Kaori; Morotomi, Takahiko; Kitamura, Chiaki

2017-08-01

The purpose of the present study was to compare the clinical efficacy between a flowable-type nano-hybrid composite and a paste-type composite for posterior restoration. Of 62 posterior teeth in 33 patients (mean age: 34.1 years), 31 were filled with a paste-type composite (Heliomolar [HM] group), and another 31 with a flowable nano-hybrid composite (MI FIL [MI] group). Clinical efficacy was evaluated at 2 years after the restoration. There were no differences for retention, surface texture deterioration, anatomical form change, deterioration of marginal adaptation, and secondary caries, while a statistical difference was found for marginal discoloration, which was significantly greater in the HM group (P < 0.05). Furthermore, color matching in the MI group was superior to that in the HM group immediately after the restoration throughout the study period. The present 2-year clinical evaluation of different composites showed that the flowable nano-hybrid composite could be an effective esthetic material for posterior restoration. © 2016 John Wiley & Sons Australia, Ltd.

Synthesis of bioactive organic-inorganic nanohybrid for bone repair through sol-gel processing.

PubMed

Miyazaki, Toshiki; Ohtsuki, Chikara; Tanihara, Masao

2003-12-01

So-called bioactive ceramics have been attractive because they form bone-like apatite on their surfaces to bond directly to living bone when implanted in bony defects. However, they are much more brittle and much less flexible than natural bone. Organic-inorganic hybrids consisting of flexible organic polymers and the essential constituents of the bioactive ceramics (i.e., Si-OH groups and Ca2+ ions) are useful as novel bone substitutes, because of their bioactivity and mechanical properties analogous to those of natural bone. In the present study, organic-inorganic nanohybrids were synthesized from hydroxyethylmethacrylate (HEMA) and methacryloxypropyltrimethoxysilane (MPS), as well as various calcium salts. Bioactivity of the synthesized hybrids was assessed in vitro by examining their acceptance of apatite deposition in simulated body fluid (Kokubo solution). The prepared hybrids formed apatite in Kokubo solution when they were modified with calcium chloride (CaCl2) at 5 or 10 mol% of the total of MPS and HEMA. Deposition of a kind of calcium phosphate was observed for the hybrids modified with calcium acetate (Ca(CH3COO)2), although it could not be identified with apatite. The addition of glycerol up to 10 mol% of the total of MPS and HEMA or water up to 20 mol% as plasticizers did not appreciably decrease the acceptance of apatite formation of the hybrids. These findings allow wide selectivity in the design of bioactive nanohybrids developed by organic modification of the Si-OH group and calcium ion through sol-gel processing. Such nanohybrids have potential as novel bone substitutes with both high bioactivity and high flexibility.

Effect of whitening dentifrices on the surface roughness of a nanohybrid composite resin

PubMed Central

da Rosa, Gabriela Migliorin; da Silva, Luciana Mendonça; de Menezes, Márcio; do Vale, Hugo Felipe; Regalado, Diego Ferreira; Pontes, Danielson Guedes

2016-01-01

Objectives: The present study verified the influence of whitening dentifrices on the surface roughness of a nanohybrid composite resin. Materials and Methods: Thirty-two specimens were prepared with Filtek™ Z350 XT (3M/ESPE) and randomly divided into four groups (n = 08) that were subjected to brushing simulation equivalent to the period of 1 month. The groups assessed were a control group with distilled water (G1), Colgate Total 12 Professional Clean (G2), Sensodyne Extra Whitener Extra Fresh (G3), and Colgate Luminous White (G4). A sequence of 90 cycles was performed for all the samples. The initial roughness of each group was analyzed by the Surface Roughness Tester (TR 200-TIME Group Inc., CA, USA). After the brushing period, the final roughness was measured, and the results were statistically analyzed using nonparametric Kruskal–Wallis and Dunn tests for intergroup roughness comparison in the time factor. For intragroup and “Δ Final − Initial” comparisons, the Wilcoxon test and (one-way) ANOVA were, respectively, performed (α = 0.05). Results: The roughness mean values before and after brushing showed no statistically significant difference when the different dentifrices were used. None of the dentifrices analyzed increased significantly the nanohybrid composite resin surface roughness in a 1 month of tooth brushing simulation. Conclusions: These results suggest that no hazardous effect on the roughness of nanohybrid composite resin can be expected when whitening dentifrices are used for a short period. Similar studies should be conducted to analyze other esthetic composite materials. PMID:27095891

Effect of Organo-Modified Nanoclay on the Thermal and Bulk Structural Properties of Poly(3-hydroxybutyrate)-Epoxidized Natural Rubber Blends: Formation of Multi-Components Biobased Nanohybrids.

PubMed

Salehabadi, Ali; Bakar, Mohamad Abu; Bakar, Noor Hana Hanif Abu

2014-06-13

Multi-component nanohybrids comprising of organo-modified montmorillonite (MMT) and immiscible biopolymer blends of poly(3-hydroxybutyrate) (PHB) and epoxidized natural rubber (ENR-50) were prepared by solvent casting technique. The one and three dimensional morphology of PHB/ENR-50/MMT systems were studied using Polarizing Optical Microscopy (POM) and Scanning Electron Microscopy (SEM). Differential scanning calorimetry (DSC) technique was used to evaluate the thermal properties of the nanohybrids. The melting temperature ( T m ) and enthalpy of melting (Δ H m ) of PHB decrease with respect to the increase in ENR-50 as well as MMT content. The non-isothermal decomposition of the nanohybrids was studied using thermogravimetric (TG-DTG) analysis. FTIR-ATR spectra supported ring opening of the epoxide group via reaction with carboxyl group of PHB and amines of organic modifier. The reaction mechanism towards the formation of the nanohybrids is proposed.

NIR-Mediated Nanohybrids of Upconversion Nanophosphors and Fluorescent Conjugated Polymers for High-Efficiency Antibacterial Performance Based on Fluorescence Resonance Energy Transfer.

PubMed

Li, Junting; Zhao, Qi; Shi, Feng; Liu, Chenghui; Tang, Yanli

2016-12-01

A novel nanohybrid comprised of upconversion nanophosphors (UCNPs) and fluorescent conjugated polymers (PFVCN) is rationally fabricated. The new UCNP/PFVCN nanohybrids combine the excellent antibacterial ability of PFVCN and the near IR (NIR) absorbing property of UCNPs, which allows for NIR-mediated antibacterial through the effective fluorescence resonance energy transfer from UCNPs to PFVCN accompanied with generation of reactive oxygen species to kill bacteria. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Theranostic GO-based nanohybrid for tumor induced imaging and potential combinational tumor therapy.

PubMed

Qin, Si-Yong; Feng, Jun; Rong, Lei; Jia, Hui-Zhen; Chen, Si; Liu, Xiang-Ji; Luo, Guo-Feng; Zhuo, Ren-Xi; Zhang, Xian-Zheng

2014-02-12

Graphene oxide (GO)-based theranostic nanohybrid is designed for tumor induced imaging and potential combinational tumor therapy. The anti-tumor drug, Doxorubicin (DOX) is chemically conjugated to the poly(ethylenimine)-co-poly(ethylene glycol) (PEI-PEG) grafted GO via a MMP2-cleavable PLGLAG peptide linkage. The therapeutic efficacy of DOX is chemically locked and its intrinsic fluorescence is quenched by GO under normal physiological condition. Once stimulated by the MMP2 enzyme over-expressed in tumor tissues, the resulting peptide cleavage permits the unloading of DOX for tumor therapy and concurrent fluorescence recovery of DOX for in situ tumor cell imaging. Attractively, this PEI-bearing nanohybrid can mediate efficient DNA transfection and shows great potential for combinational drug/gene therapy. This tumor induced imaging and potential combinational therapy will open a window for tumor treatment by offering a unique theranostic approach through merging the diagnostic capability and pathology-responsive therapeutic function. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Anionic clay as the drug delivery vehicle: tumor targeting function of layered double hydroxide-methotrexate nanohybrid in C33A orthotopic cervical cancer model.

PubMed

Choi, Goeun; Piao, Huiyan; Alothman, Zeid A; Vinu, Ajayan; Yun, Chae-Ok; Choy, Jin-Ho

2016-01-01

Methotrexate (MTX), an anticancer agent, was successfully intercalated into the anionic clay, layered double hydroxides to form a new nanohybrid drug. The coprecipitation and subsequent hydrothermal method were used to prepare chemically, structurally, and morphologically well-defined two-dimensional drug-clay nanohybrid. The resulting two-dimensional drug-clay nanohybrid showed excellent colloidal stability not only in deionized water but also in an electrolyte solution of Dulbecco's Modified Eagle's Medium with 10% fetal bovine serum, in which the average particle size in colloid and the polydispersity index were determined to be around 100 and 0.250 nm, respectively. The targeting property of the nanohybrid drug was confirmed by evaluating the tumor-to-blood and tumor-to-liver ratios of the MTX with anionic clay carrier, and these ratios were compared to those of free MTX in the C33A orthotopic cervical cancer model. The biodistribution studies indicated that the mice treated with the former showed 3.5-fold higher tumor-to-liver ratio and fivefold higher tumor-to-blood ratio of MTX than those treated with the latter at 30 minutes postinjection.

Biomass hydrolysis inhibition at high hydrogen partial pressure in solid-state anaerobic digestion.

PubMed

Cazier, E A; Trably, E; Steyer, J P; Escudie, R

2015-08-01

In solid-state anaerobic digestion, so-called ss-AD, biogas production is inhibited at high total solids contents. Such inhibition is likely caused by a slow diffusion of dissolved reaction intermediates that locally accumulate. In this study, we investigated the effect of H2 and CO2 partial pressure on ss-AD. Partial pressure of H2 and/or CO2 was artificially fixed, from 0 to 1 557mbars for H2 and from 0 to 427mbars for CO2. High partial pressure of H2 showed a significant effect on methanogenesis, while CO2 had no impact. At high [Formula: see text] , the overall substrate degradation decreased with no accumulation of metabolites from acidogenic bacteria, indicating that the hydrolytic activity was specifically impacted. Interestingly, such inhibition did not occur when CO2 was added with H2. This result suggests that CO2 gas transfer is probably a key factor in ss-AD from biomass. Copyright © 2015 Elsevier Ltd. All rights reserved.

Semiconducting carbon nanotube and covalent organic polyhedron-C60 nanohybrids for light harvesting.

PubMed

Lohrman, Jessica; Zhang, Chenxi; Zhang, Wei; Ren, Shenqiang

2012-08-28

We demonstrate noncovalent electrostatic and π-π interactions to assemble semiconducting single wall carbon nanotube (SWCNT)-C(60)@COP nanohybrids. The C(60)@COP light harvesting complexes bind strongly to SWCNTs due to significant π-π-stacking between C(60), the aromatic dicarbazolylacetylene moieties and the nanotube surfaces.

Modified ADM1 for modeling free ammonia inhibition in anaerobic acidogenic fermentation with high-solid sludge.

PubMed

Bai, Jie; Liu, He; Yin, Bo; Ma, Huijun; Chen, Xinchun

2017-02-01

Anaerobic acidogenic fermentation with high-solid sludge is a promising method for volatile fatty acid (VFA) production to realize resource recovery. In this study, to model inhibition by free ammonia in high-solid sludge fermentation, the anaerobic digestion model No. 1 (ADM1) was modified to simulate the VFA generation in batch, semi-continuous and full scale sludge. The ADM1 was operated on the platform AQUASIM 2.0. Three kinds of inhibition forms, e.g., simple inhibition, Monod and non-inhibition forms, were integrated into the ADM1 and tested with the real experimental data for batch and semi-continuous fermentation, respectively. The improved particle swarm optimization technique was used for kinetic parameter estimation using the software MATLAB 7.0. In the modified ADM1, the K s of acetate is 0.025, the k m,ac is 12.51, and the K I_NH3 is 0.02, respectively. The results showed that the simple inhibition model could simulate the VFA generation accurately while the Monod model was the better inhibition kinetics form in semi-continuous fermentation at pH10.0. Finally, the modified ADM1 could successfully describe the VFA generation and ammonia accumulation in a 30m 3 full-scale sludge fermentation reactor, indicating that the developed model can be applicable in high-solid sludge anaerobic fermentation. Copyright © 2016. Published by Elsevier B.V.

Novel nanohybrid materials for the effective removal of phosphates and nitrates from liquid effluents

NASA Astrophysics Data System (ADS)

Eroglu, Ela; Haniff Wahid, M.; Boulos, Ramiz A.; Chen, Xianjue; Eggers, Paul K.; Toster, Jeremiah; D'Alonzo, Nicholas J.; Smith, Steven M.; Raston, Colin L.

2014-05-01

Within our research group, various types of nanofabrication processes have been applied for creating novel nanohybrid materials, including the immobilization of some microorganisms with electrospun nanofibres1, laminar nanomaterials (i.e. graphene and graphene oxide)2,3, microfibers of human hair4, and magnetic nanoparticles impregnated in polymer5. These approaches afford nanohybrid materials with microalgal cells1-5 or diatom frustules6 for the removal of waste pollutants, mainly nitrate and phosphate ions, while establishing a new paradigm in the field. Aside from these immobilization studies, we also investigated the improvement of nitrate removal with exfoliated graphene sheets in the presence of p-phosphonic acid calix[8]arene molecules.7 Various material characterization techniques such as scanning electron microscopy, transmission electron microscopy, atomic force microscopy, and Raman spectroscopy were used for the characterization of the novel nanohybrid materials, while fluorescence microscopy and chlorophyll content analysis were mainly used for monitoring the viability and growth pattern of the microalgal cells. Nitrate and phosphate analyses were carried out by following HACH® standard methods. In this talk, a brief overview of the fabrication processes of these nanohybrid materials and their application for wastewater treatment will be highlighted. 1. E. Eroglu, V. Agarwal, M. Bradshaw, X. Chen, S.M. Smith, C.L. Raston and K.S. Iyer, Green Chemistry, 2012, 14(10), 2682 - 2685. 2. M.H. Wahid, E. Eroglu, X. Chen, S.M. Smith and C.L. Raston, Green Chemistry, 2013, 15(3), 650-655. 3. M.H. Wahid, E. Eroglu, X. Chen, S.M. Smith and C.L. Raston, RSC Advances, 2013, 3(22), 8180-8183. 4. R.A. Boulos, E. Eroglu, X. Chen, A. Scaffidi, J. Toster, B. Edwards and C.L. Raston, Green Chemistry, 2013, 15(5), 1268-1273. 5. E. Eroglu, N.J. D'Alonzo, S.M. Smith and C.L. Raston, Nanoscale, 2013, 5(7), 2627-2631. 6. J. Toster, I. Kusumawardani, E. Eroglu, K.S. Iyer, F

Bandgap- and local field-dependent photoactivity of Ag/black phosphorus nanohybrids

DOE PAGES

Lei, Wanying; Zhang, Tingting; Liu, Ping; ...

2016-10-18

Black phosphorus (BP) is the most exciting post-graphene layered nanomaterial that serendipitously bridges the 2D materials gap between semimetallic graphene and large bandgap transition-metal dichalcogenides in terms of high charge-carrier mobility and tunable direct bandgap, yet research into BP-based solar to chemical energy conversion is still in its infancy. Herein, a novel hybrid photocatalyst with Ag nanoparticles supported on BP nanosheets is prepared using a chemical reduction approach. Spin-polarized density functional theory (DFT) calculations show that Ag nanoparticles are stabilized on BP by covalent bonds at the Ag/BP interface and Ag–Ag interactions. In the visible-light photocatalysis of rhodamine B bymore » Ag/BP plasmonic nanohybrids, a significant rise in photoactivity compared with pristine BP nanosheets is observed either by decreasing BP layer thickness or increasing Ag particle size, with the greatest enhancement being up to ~20-fold. By virtue of finite-difference time domain (FDTD) simulations and photocurrent measurements, we give insights into the enhanced photocatalytic performance of Ag/BP nanohybrids, including the effects of BP layer thickness and Ag particle size. In comparison with BP, Ag/BP nanohybrids present intense local field amplification at the perimeter of Ag NPs, which is increased by either decreasing the BP layer thickness from multiple to few layers or increasing the Ag particle size from 20 to 40 nm. Additionally, when the BP layer thickness is decreased from multiple to few layers, the bandgap becomes favorable to generate more strongly oxidative holes in the proximity of the Ag/BP interface to enhance photoactivity. Our findings illustrate a synergy between locally enhanced electric fields and BP bandgap, in which BP layer thickness and Ag particle size can be independently tuned to enhance photoactivity. Lastly, this study may open a new avenue for further exploiting BP-based plasmonic nanostructures in

Bandgap- and local field-dependent photoactivity of Ag/black phosphorus nanohybrids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lei, Wanying; Zhang, Tingting; Liu, Ping

Black phosphorus (BP) is the most exciting post-graphene layered nanomaterial that serendipitously bridges the 2D materials gap between semimetallic graphene and large bandgap transition-metal dichalcogenides in terms of high charge-carrier mobility and tunable direct bandgap, yet research into BP-based solar to chemical energy conversion is still in its infancy. Herein, a novel hybrid photocatalyst with Ag nanoparticles supported on BP nanosheets is prepared using a chemical reduction approach. Spin-polarized density functional theory (DFT) calculations show that Ag nanoparticles are stabilized on BP by covalent bonds at the Ag/BP interface and Ag–Ag interactions. In the visible-light photocatalysis of rhodamine B bymore » Ag/BP plasmonic nanohybrids, a significant rise in photoactivity compared with pristine BP nanosheets is observed either by decreasing BP layer thickness or increasing Ag particle size, with the greatest enhancement being up to ~20-fold. By virtue of finite-difference time domain (FDTD) simulations and photocurrent measurements, we give insights into the enhanced photocatalytic performance of Ag/BP nanohybrids, including the effects of BP layer thickness and Ag particle size. In comparison with BP, Ag/BP nanohybrids present intense local field amplification at the perimeter of Ag NPs, which is increased by either decreasing the BP layer thickness from multiple to few layers or increasing the Ag particle size from 20 to 40 nm. Additionally, when the BP layer thickness is decreased from multiple to few layers, the bandgap becomes favorable to generate more strongly oxidative holes in the proximity of the Ag/BP interface to enhance photoactivity. Our findings illustrate a synergy between locally enhanced electric fields and BP bandgap, in which BP layer thickness and Ag particle size can be independently tuned to enhance photoactivity. Lastly, this study may open a new avenue for further exploiting BP-based plasmonic nanostructures in

Shape matters: Cr(VI) removal using iron nanoparticle impregnated 1-D vs 2-D carbon nanohybrids prepared by ultrasonic spray pyrolysis

NASA Astrophysics Data System (ADS)

Masud, Arvid; Cui, Yanbin; Atkinson, John D.; Aich, Nirupam

2018-03-01

Iron nanoparticles (Fe NPs) are used for treating water contaminated with metals or organic compounds. One-dimensional (1-D) carbon nanotubes (CNTs) and two-dimensional (2-D) graphenes act as useful nanocarbon (NC) supports for Fe NPs by resisting aggregation and enhancing adsorption and redox activity. However, no study showed how shape difference between tubular CNT and planar graphene structures dictates the physicochemical properties and pollutant removal potential of their iron-based nanohybrids. In this work, ultrasonic spray pyrolysis was used to continuously prepare Fe-CNT and Fe-rGO nanohybrids. Both NC shape and Fe/NC ratio influenced Fe NP size, loading, and oxidation states. High Fe content (precursor Fe/NC mass ratio = 2) resulted Fe NPs with diameters of 30.97 ± 7.00 and 24.11 ± 4.42 nm for Fe-CNT and Fe-rGO, respectively; however, low Fe content (Fe/NC = 0.2) provided more uniformly dispersed Fe NPs of 15.65 ± 3.06 and 9.67 ± 1.49 nm, respectively, while unsupported Fe NPs were 285.71 ± 132.42 nm. The USP-derived nanohybrids, for the first time, were used for removal of pollutant, i.e., chromium (Cr(VI)) from aqueous media. Both CNT and rGO provided synergistic effects to significantly enhance Fe NPs' ability to remove Cr(VI); the effect was more pronounced in Fe-rGO than Fe-CNT and also for low Fe content in both cases. Fe-rGO with low Fe/NC ratio and smallest Fe NPs provided the highest Cr(VI) removal capacity (25 mg/g), which was a multifold improvement over bare Fe NPs and other synthesized nanohybrids (range 7-14 mg/g). Overall, 2-D rGO improved contaminant removal capacity of the nanohybrids more than 1-D CNT indicating towards shape effect of NC supports. [Figure not available: see fulltext.

Immobilization of silver nanoparticles on exfoliated mica nanosheets to form highly conductive nanohybrid films

NASA Astrophysics Data System (ADS)

Chiu, Chih-Wei; Ou, Gang-Bo; Tsai, Yu-Hsuan; Lin, Jiang-Jen

2015-11-01

Highly electrically conductive films were prepared by coating organic/inorganic nanohybrid solutions with a polymeric dispersant and exfoliated mica nanosheets (Mica) on which silver nanoparticles (AgNPs) had been dispersed in various components. Transmission electronic microscopy showed that the synthesized AgNPs had a narrow size distribution and a diameter of approximately 20 nm. Furthermore, a 60 μm thick film with a sheet resistance as low as 4.5 × 10-2 Ω/sq could be prepared by controlling the heating temperature and by using AgNPs/POE-imide/Mica in a weight ratio of 20:20:1. During the heating process, the surface color of the hybrid film changed from dark golden to white, suggesting the accumulation of the AgNPs through surface migration and their melting to form an interconnected network. These nanohybrid films have potential for use in various electrically conductive devices.

Can magneto-plasmonic nanohybrids efficiently combine photothermia with magnetic hyperthermia?

PubMed

Espinosa, Ana; Bugnet, Mathieu; Radtke, Guillaume; Neveu, Sophie; Botton, Gianluigi A; Wilhelm, Claire; Abou-Hassan, Ali

2015-12-07

Multifunctional hybrid-design nanomaterials appear to be a promising route to meet the current therapeutics needs required for efficient cancer treatment. Herein, two efficient heat nano-generators were combined into a multifunctional single nanohybrid (a multi-core iron oxide nanoparticle optimized for magnetic hyperthermia, and a gold branched shell with tunable plasmonic properties in the NIR region, for photothermal therapy) which impressively enhanced heat generation, in suspension or in vivo in tumours, opening up exciting new therapeutic perspectives.

High-performance glucose biosensor based on chitosan-glucose oxidase immobilized polypyrrole/Nafion/functionalized multi-walled carbon nanotubes bio-nanohybrid film.

PubMed

Shrestha, Bishnu Kumar; Ahmad, Rafiq; Mousa, Hamouda M; Kim, In-Gi; Kim, Jeong In; Neupane, Madhav Prasad; Park, Chan Hee; Kim, Cheol Sang

2016-11-15

A highly electroactive bio-nanohybrid film of polypyrrole (PPy)-Nafion (Nf)-functionalized multi-walled carbon nanotubes (fMWCNTs) nanocomposite was prepared on the glassy carbon electrode (GCE) by a facile one-step electrochemical polymerization technique followed by chitosan-glucose oxidase (CH-GOx) immobilization on its surface to achieve a high-performance glucose biosensor. The as-fabricated nanohybrid composite provides high surface area for GOx immobilization and thus enhances the enzyme-loading efficiency. The structural characterization revealed that the PPy-Nf-fMWCNTs nanocomposite films were uniformly formed on GCE and after GOx immobilization, the surface porosities of the film were decreased due to enzyme encapsulation inside the bio-nanohybrid composite materials. The electrochemical behavior of the fabricated biosensor was investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and amperometry measurements. The results indicated an excellent catalytic property of bio-nanohybrid film for glucose detection with improved sensitivity of 2860.3μAmM(-1)cm(-2), the linear range up to 4.7mM (R(2)=0.9992), and a low detection limit of 5μM under a signal/noise (S/N) ratio of 3. Furthermore, the resulting biosensor presented reliable selectivity, better long-term stability, good repeatability, reproducibility, and acceptable measurement of glucose concentration in real serum samples. Thus, this fabricated biosensor provides an efficient and highly sensitive platform for glucose sensing and can open up new avenues for clinical applications. Copyright © 2016 Elsevier Inc. All rights reserved.

Photothermal and mechanical stimulation of cells via dualfunctional nanohybrids

NASA Astrophysics Data System (ADS)

Chechetka, Svetlana A.; Doi, Motomichi; Pichon, Benoit P.; Bégin-Colin, Sylvie; Miyako, Eijiro

2016-11-01

Stimulating cells by light is an attractive technology to investigate cellular function and deliver innovative cell-based therapy. However, current techniques generally use poorly biopermeable light, which prevents broad applicability. Here, we show that a new type of composite nanomaterial, synthesized from multi-walled carbon nanotubes, magnetic iron nanoparticles, and polyglycerol, enables photothermal and mechanical control of Ca2+ influx into cells overexpressing transient receptor potential vanilloid type-2. The nanohybrid is simply operated by application of highly biotransparent near-infrared light and a magnetic field. The technology may revolutionize remote control of cellular function.

Anionic clay as the drug delivery vehicle: tumor targeting function of layered double hydroxide-methotrexate nanohybrid in C33A orthotopic cervical cancer model

PubMed Central

Choi, Goeun; Piao, Huiyan; Alothman, Zeid A; Vinu, Ajayan; Yun, Chae-Ok; Choy, Jin-Ho

2016-01-01

Methotrexate (MTX), an anticancer agent, was successfully intercalated into the anionic clay, layered double hydroxides to form a new nanohybrid drug. The coprecipitation and subsequent hydrothermal method were used to prepare chemically, structurally, and morphologically well-defined two-dimensional drug-clay nanohybrid. The resulting two-dimensional drug-clay nanohybrid showed excellent colloidal stability not only in deionized water but also in an electrolyte solution of Dulbecco’s Modified Eagle’s Medium with 10% fetal bovine serum, in which the average particle size in colloid and the polydispersity index were determined to be around 100 and 0.250 nm, respectively. The targeting property of the nanohybrid drug was confirmed by evaluating the tumor-to-blood and tumor-to-liver ratios of the MTX with anionic clay carrier, and these ratios were compared to those of free MTX in the C33A orthotopic cervical cancer model. The biodistribution studies indicated that the mice treated with the former showed 3.5-fold higher tumor-to-liver ratio and fivefold higher tumor-to-blood ratio of MTX than those treated with the latter at 30 minutes postinjection. PMID:26855572

Facile synthesis and enhanced photocatalytic activity of single-crystalline nanohybrids for the removal of organic pollutants

NASA Astrophysics Data System (ADS)

Pervaiz, Erum; Liu, Honghong; Yang, Minghui

2017-03-01

This study focused on the synthesis of α-MoO3/rGO (rGO, reduced graphene oxide). One-dimensional nanohybrids under mild conditions and a low temperature wet chemical route produced highly pure single-crystalline orthorhombic α-MoO3 on GO sheets. Four nanohybrids, labeled as GMO-0, GMO-1, GMO-2 and GMO-3, were synthesized with different mass chargings of GO (0 mg, 40 mg, 60 mg and 100 mg, respectively). The photocatalytic performance for reduction of organic pollutants was analyzed. The presence of different amounts of GO in the prepared metal oxide hybrids altered the performance of the material as elaborated by the Brunauer-Emmett-Teller surface area, UV-visible diffuse reflectance spectra and the resulting reduction of organic dyes depicted by photocatalytic experiments. GO as a support material and active co-catalyst decreased the band gap of α-MoO3 (2.82 eV) to lower values (2.51 eV), rendering the prepared hybrids usable for visible-light-induced photocatalysis. The large specific surface area (72 m2 g-1) of the mesoporous α-MoO3/rGO nanohybrid made it an efficient photocatalyst for the elimination of azo dyes. Very fast reduction (100%) of Rhodamine B was observed in a few minutes, while Congo Red was degraded by 76% in 10 min, leading to the formation of stable intermediates that were completely neutralized in 12-14 h under light irradiation. The amount of GO loaded in the samples was limited to a point to achieve better results. After that, increasing the amount of GO decreased the extent of degradation due to the presence of a higher electron acceptor. Photocatalytic experiments revealed the synergistic effect, high selectivity of the prepared nanohybrids and degradation of azo dyes. The kinetics of the degradation reaction were studied and found to follow a pseudo first-order reaction.

Phosphorescent quantum dots/ethidium bromide nanohybrids based on photoinduced electron transfer for DNA detection.

PubMed

Bi, Lin; Yu, Yuan-Hua

2015-04-05

Mercaptopropionic acid-capped Mn-doped ZnS quantum dots/ethidium bromide (EB) nanohybrids were constructed for photoinduced electron transfer (PIET) and then used as a room-temperature phosphorescence (RTP) probe for DNA detection. EB could quench the RTP of Mn-doped ZnS QDs by PIET, thereby forming Mn-doped ZnS QDs/EB nanohybrids and storing RTP. Meanwhile, EB could be inserted into DNA and EB could be competitively desorbed from the surface of Mn-doped ZnS QDs by DNA, thereby releasing the RTP of Mn-doped ZnS QDs. Based on this mechanism, a RTP sensor for DNA detection was developed. Under optimal conditions, the detection limit for DNA was 0.045 mg L(-1), the relative standard deviation was 1.7%, and the method linear ranged from 0.2 to 20 mg L(-1). The proposed method was applied to biological fluids, in which satisfactory results were obtained. Copyright © 2015 Elsevier B.V. All rights reserved.

Polysulfone ultrafiltration membrane incorporated with Ag-SiO2 nanohybrid for effective fouling control.

PubMed

Wu, Huiqing; Huang, Jing; Liu, Yuejun

2017-06-01

An anti-fouling hybrid membrane was prepared by incorporating Ag-SiO 2 nanohybrid into a polysulfone (PSf) matrix. The addition of Ag-SiO 2 can significantly improve the hydrophilicity, separation property, anti-fouling ability, and especially anti-bacterial activity of hybrid membranes. The optimum performance of the Ag-SiO 2 /PSf hybrid membrane is achieved when the concentration of Ag-SiO 2 is as low as 0.45 wt%. Compared with PSf membrane and SiO 2 /PSf hybrid membrane, the Ag-SiO 2 /PSf hybrid membrane displays the best overall properties. The excellent performance of the Ag-SiO 2 /PSf hybrid membrane can be attributed to the well-tailored structure and unique property of Ag-SiO 2 nanohybrid, where nanosized Ag (∼5 nm) can densely and uniformly disperse on the surface of silica spheres. The obtained membrane could be a promising material for water treatment.

Controllable synthesis of Au@SnO2 core-shell nanohybrids with enhanced photocatalytic activities

NASA Astrophysics Data System (ADS)

Zhang, Shaofeng; Hao, Jinggang; Ren, Feng; Wu, Wei; Xiao, Xiangheng

2017-05-01

Combination of semiconductors with plasmonic nanostructures is an effective route to promote the solar light harvesting as well as the efficiency of photocatalysis. In the present work, the Au@SnO2 hybrid nanostructures with Au nanorods as the cores and highly crystallized SnO2 nanoparticles as the shells were fabricated by a facile hydrothermal method. A critical factor, which influences the coating state of the SnO2 shells over Au NRs, was found to be the concentration of CTAB agent in the system and the corresponding mechanism was also proposed. The photocatalytic activities of the Au@SnO2 nanohybrids were examined by degradation of rhodamine B (RhB) dyes at room temperature. The Au@SnO2 nanohybrids exhibited much higher catalytic activities than that of the commercial SnO2 NPs, which could be attributed to the localized electric field enhancement effect of Au nanorods plasmon and charges transfer between the Au nanorods and SnO2.

Platinum-paper micromotors: an urchin-like nanohybrid catalyst for green monopropellant bubble-thrusters.

PubMed

Claussen, Jonathan C; Daniele, Michael A; Geder, Jason; Pruessner, Marius; Mäkinen, Antti J; Melde, Brian J; Twigg, Mark; Verbarg, Jasenka M; Medintz, Igor L

2014-10-22

Platinum nanourchins supported on microfibrilated cellulose films (MFC) were fabricated and evaluated as hydrogen peroxide catalysts for small-scale, autonomous underwater vehicle (AUV) propulsion systems. The catalytic substrate was synthesized through the reduction of chloroplatinic acid to create a thick film of Pt coral-like microstructures coated with Pt urchin-like nanowires that are arrayed in three dimensions on a two-dimensional MFC film. This organic/inorganic nanohybrid displays high catalytic ability (reduced activation energy of 50-63% over conventional materials and 13-19% for similar Pt nanoparticle-based structures) during hydrogen peroxide (H2O2) decomposition as well as sufficient propulsive thrust (>0.5 N) from reagent grade H2O2 (30% w/w) fuel within a small underwater reaction vessel. The results demonstrate that these layered nanohybrid sheets are robust and catalytically effective for green, H2O2-based micro-AUV propulsion where the storage and handling of highly explosive, toxic fuels are prohibitive due to size-requirements, cost limitations, and close person-to-machine contact.

Effect of sealant agents on the color stability and surface roughness of nanohybrid composite resins.

PubMed

Dede, Doğu Ömür; Şahin, Onur; Koroglu, Aysegül; Yilmaz, Burak

2016-07-01

The effect of sealant agents on the surface roughness and color stability of nanohybrid composite resins is unknown. The purpose of this in vitro study was to evaluate the effect of sealant agents on the surface roughness and color stability of 4 nanohybrid composite resin materials. Forty disks (10×2 mm) were fabricated for each nanohybrid composite resin material (Z-550, Tetric EvoCeram, Clearfill Majesty, Ice) (N=160) and divided into 4 surface treatment groups: 1 conventional polishing (control) and 3 different sealant agent (Palaseal, Optiglaze, BisCover) coupling groups (n=10). The specimens were thermocycled, and surface roughness (Ra) values were obtained with a profilometer. Scanning electron microscope images were also recorded. CIELab color parameters of each specimen were measured with a spectrophotometer before and after 7 days of storage in a coffee solution. Color differences were calculated by the CIEDE 2000 (ΔE00) formula. The data were statistically analyzed by 2-way ANOVA and by the Tukey HSD test (α=.05). The surface treatment technique significantly affected the Ra values of the composite resins tested (P<.001). The interaction between the surface treatment technique and composite resin material was also significant for ΔE00 values (P<.05). Within the composite resin groups, significant decreases in Ra were observed only for the Palaseal agent coupled composite resin groups (except Ice) compared with the control groups (P<.05). Scanning electron microscope images revealed rougher surfaces with conventionally polished groups compared with test groups. Conventionally polished groups had the highest ΔE00 (3.09 to 3.49) values for each composite resin group, except for BisCover applied Clearfill Majesty (P<.05). Within the composite resin groups, significant differences were observed between the color change seen with BisCover and other sealants for Clearfill Majesty composite resin (P<.05). Using Palaseal agent on all tested composite

Novel "203" type of heterostructured MoS2-Fe3O4-C ternary nanohybrid: Synthesis, and enhanced microwave absorption properties

NASA Astrophysics Data System (ADS)

Yang, Erqi; Qi, Xiaosi; Xie, Ren; Bai, Zhongchen; Jiang, Yang; Qin, Shuijie; Zhong, Wei; Du, Youwei

2018-06-01

It is widely recognized that constructing multiple interface structures to enhance interface polarization is very good for the attenuation of electromagnetic (EM) wave. Here, a novel "203" type of heterostructured nanohybrid consisting of two-dimensional (2D) MoS2 nanosheets, zero-dimensional (0D) Fe3O4 nanoparticles and three-dimensional (3D) carbon layers was elaborately designed and successfully synthesized by a two-step method: Fe3O4 nanoparticles were deposited onto the surface of few-layer MoS2 nanosheets by a hydrothermal method, followed by the carbonation process by a chemical vapor deposition method. Compared to that of "20" type MoS2-Fe3O4, the as-prepared heterostructured "203" type MoS2-Fe3O4-C ternary nanohybrid exhibited remarkably enhanced EM and microwave absorption properties. And the minimum reflection loss (RL) value of the obtained MoS2-Fe3O4-C ternary nanohybrid could reach -53.03 dB at 14.4 GHz with a matching thickness of 7.86 mm. Moreover, the excellent EM wave absorption property of the as-prepared ternary nanohybrid was proved to be attributed to the quarter-wavelength matching model. Therefore, a simple and effective route was proposed to produce MoS2-based mixed-dimensional van der Waals heterostructure, which provided a new platform for the designing and production of high performance microwave absorption materials.

Sonocatalytic performance of magnetically separable CuS/CoFe2O4 nanohybrid for efficient degradation of organic dyes.

PubMed

Siadatnasab, Firouzeh; Farhadi, Saeed; Khataee, Alireza

2018-06-01

The sonocatalytic activity of the magnetic CuS/CoFe 2 O 4 (CuS/CFO) nanohybrid was studied through the H 2 O 2 -assisted system for degradation of water soluble organic pollutants such as methylene blue (MB), rhodamine B (RhB) and methyl orange (MO). The CuS/CFO nanohybrid was fabricated at 200 °C by hydrothermal method. X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM) equipped with energy dispersive X-ray microanalysis (EDX), Fourier-transform infrared spectroscopy (FT-IR), UV-Vis spectroscopy, magnetic measurements, and Brunauere-Emmette-Teller (BET) were employed for the characterizing the structure and morphology of the so-synthesized nanohybrid. Compared with sonolysis/H 2 O 2 , the higher degradation of MB (25 mg/L) was achieved via sonocatalytic process. The degradation efficiency of sonolysis/H 2 O 2 , sonocatalysis using CuS/H 2 O 2 , CFO/H 2 O 2 and CuS/CFO/H 2 O 2 systems was 6%, 62%, 23% and 100% within reaction time of 30 min for MB, respectively. The integration of H 2 O 2 and catalyst dosage intensified the sonocatalytic degradation of MB. On the other hand, adding a hydroxyl radical (OH) scavenger (tert-butyl alcohol) and a hole scavenger (disodium ethylenediaminetetraacetate) decreased the degradation efficiency from 100% to 35% and 72% within 30 min, indicating the OH radicals as prominent oxidizing agent of this process. Furthermore, the magnetic property of the sample helped for easier separation of the nanohybrid, made it recyclable with a negligible decline in the performance even after four consecutive runs. Copyright © 2018 Elsevier B.V. All rights reserved.

Enzyme-guided plasmonic biosensor based on dual-functional nanohybrid for sensitive detection of thrombin.

PubMed

Yan, Jing; Wang, Lida; Tang, Longhua; Lin, Lei; Liu, Yang; Li, Jinghong

2015-08-15

Rapid and sensitive methodologies for the detection of protein are in urgent requirement for clinic diagnostics. Localized surface plasmon resonance (LSPR) of metal nanostructures has the potential to circumvent this problem due to its sensitive optical properties and strong electromagnetic near-field enhancements. In this work, an enzyme mediated plasmonic biosensor on the basis of a dual-functional nanohybrid was developed for the detection of thrombin. By utilizing LSPR-responsive nanohybrid and anaptamer-enzyme conjugated reporting probe, the sensing platform brings enhanced signal, stability as well as simplicity. Enzymatic reaction catalyzed the reduction of Au(3+) to Au° in situ, further leading to the rapid crystal growth of gold nanoparticles (AuNPs). The LSPR absorbance band and color changed company with the nanoparticle generation, which can be real-time monitoring by UV-visible spectrophotometer and naked eye. Nanohybrid constructed by gold and magnetic nanoparticles acts as a dual functional plasmonic unit, which not only plays the role of signal production, but also endows the sensor with the function of magnetic separation. Simultaneously, the introduction of enzyme effectively regulates the programming crystal growth of AuNPs. In addition, enzyme also serves as signal amplifier owing to its high catalysis efficiency. The response of the plasmonic sensor varies linearly with the logarithmic thrombin concentration up to 10nM with a limit of detection of 200 pM. The as-proposed strategy shows good analytical performance for thrombin determination. This simple, disposable method is promising in developing universal platforms for protein monitoring, drug discovery and point-of-care diagnostics. Copyright © 2015 Elsevier B.V. All rights reserved.

A self-assembled nanohybrid composed of fluorophore-phenylamine nanorods and Ag nanocrystals: energy transfer, wavelength shift of fluorescence and TPEF applications for live-cell imaging.

PubMed

Kong, Lin; Yang, Jia-xiang; Li, Sheng-li; Zhang, Qiong; Xue, Zhao-ming; Zhou, Hong-ping; Wu, Jie-ying; Jin, Bao-kang; Tian, Yu-peng

2013-12-02

A fluorophore-phenylamine derivative (L) has been coupled with silver nanocrystals (NCs) to construct an L-Ag nanohybrid. Owing to synergic effects of the L and Ag components, the exciton-plasmon interactions between L and Ag increase the strength of the donor-acceptor interaction within the nanohybrid, a fact that results in an energy-transfer process and further brings about a dramatic redshift of single-photon absorption and fluorescence, and a decreased fluorescence FL lifetime. The coupling effect also leads to enhancement of a series of nonlinear optical properties, including two-photon-excited fluorescence (TPEF), two-photon-absorption (TPA) cross section (δ), two-photon-absorption coefficient (β), nonlinear refractive index (γ), and third order nonlinear optical susceptibility (χ((3))). The enhanced two-photon fluorescence of the nanohybrid is proven to be potentially useful for two-photon microscopy of live cells, such as HepG2. Moreover, cytotoxicity tests show that the low-micromolar concentrations of the nanohybrid do not cause significant reduction in cell viability over a period of at least 24 h and should be safe for further biological studies. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Highly-efficient forward osmosis membrane tailored by magnetically responsive graphene oxide/Fe3O4 nanohybrid

NASA Astrophysics Data System (ADS)

Rastgar, Masoud; Shakeri, Alireza; Bozorg, Ali; Salehi, Hasan; Saadattalab, Vahid

2018-05-01

Emerging forward osmosis (FO) process as a potentially more energy efficient method has recently gained remarkable attention. Herein, considering the unique features of graphene oxide (GO), a new facile method has been proposed to magnetically modify GO within the polyamide active layer to obtain highly efficient osmotically driven membranes. While exposed to magnetic field, thin film nanocomposite membranes modified by GO/Fe3O4 nanohybrids (TFN-MMGO/Fe3O4) were synthesized by in-situ interfacial polymerization of the prepared monomer solution and organic trimesoyl chloride. Water permeability, salt rejection, and fouling tendency of the modified membranes were then evaluated and compared with both pristine thin film composite (TFC) membrane and the ones modified by GO/Fe3O4 nanohybrides in the absence of magnetic field (TFN-GO/Fe3O4). According to the experimental results, when compared to the TFC and TFN-GO/Fe3O4 membranes, respectively, 117.4% and 63.2% water flux enhancements were achieved in TFN-MMGO/Fe3O4 membrane with optimal GO/Fe3O4 nanohybrid concentration of 100 ppm. In spite of such improvements in water flux, little compromise in reverse salt leakages were observed in the TFN-MMGO/Fe3O4 membranes compared to the TFC one. As well, the TFN-MMGO/Fe3O4 and TFN-GO/Fe3O4 membranes revealed higher fouling resistances than the TFC membrane due to their distinguished manipulated surface characteristics.

Protein-lipid nanohybrids as emerging platforms for drug and gene delivery: Challenges and outcomes.

PubMed

Gaber, Mohamed; Medhat, Waseem; Hany, Mark; Saher, Nourhan; Fang, Jia-You; Elzoghby, Ahmed

2017-05-28

Nanoparticulate drug delivery systems have been long used to deliver a vast range of drugs and bioactives owing to their ability to demonstrate novel physical, chemical, and/or biological properties. An exponential growth has spurred in research and development of these nanocarriers which led to the evolution of a great number of diverse nanosystems including liposomes, nanoemulsions, solid lipid nanoparticles (SLNs), micelles, dendrimers, polymeric nanoparticles (NPs), metallic NPs, and carbon nanotubes. Among them, lipid-based nanocarriers have made the largest progress whether commercially or under development. Despite this progress, these lipid-based nanocarriers suffer from several limitations that led to the development of many protein-coated lipid nanocarriers. To less extent, protein-based nanocarriers suffer from limitations that led to the fabrication of some lipid bilayer enveloping protein nanocarriers. This review discusses in-depth some limitations associated with the lipid-based or protein-based nanocarriers and the fruitful outcomes brought by protein-lipid hybridization. Also discussed are the various hybridization techniques utilized to formulate these protein-lipid nanohybrids and the mechanisms involved in the drug loading process. Copyright © 2017 Elsevier B.V. All rights reserved.

Colorimetric determination of glutathione by using a nanohybrid composed of manganese dioxide and carbon dots.

PubMed

Wang, Qian; Pang, Hongchang; Dong, Yongqiang; Chi, Yuwu; Fu, Fengfu

2018-05-10

A kind of single-layer carbon based dots (CDs) with abundant carboxyl functional groups was hybridized with manganese dioxide (MnO 2 ). The resulting nanohybrid is stable and can be well dispersed in water. MnO 2 is capable of oxidizing the substrate 3,3'5,5'-tetramethylbenzidine (TMB) to form a blue product whose absorption (peaking at 655 nm) fades in the presence of glutathione (GSH). A sensitive and selective colorimetric GSH assay was worked out that has a linear response in the 10 to 0.1 µM GSH concentration range, with a 0.095 μM detection limit. The method was applied to the determination of GSH in spiked fetal calf serum where it gave excellent recoveries. Graphical abstract Schematic of the preparation of a nanohybrid composed of manganese dioxide and carbon based dots (MnO 2 /CDs). They can be used for the colorimetric detection of glutathione (GSH) based on the color change of 3,3'5,5'-tetramethylbenzidine (TMB).

Sonochemical assisted synthesis MnO2/RGO nanohybrid as effective electrode material for supercapacitor.

PubMed

Ghasemi, Shahram; Hosseini, Sayed Reza; Boore-Talari, Omid

2018-01-01

Manganese dioxide (MnO 2 ) needle-like nanostructures are successfully synthesized by a sonochemical method from an aqueous solution of potassium bromate and manganese sulfate. Also, hybride of MnO 2 nanoparticles wrapped with graphene oxide (GO) nanosheets are fabricated through an electrostatic coprecipitation procedure. With adjusting pH at 3.5, positive and negative charges are created on MnO 2 and on GO, respectively which can electrostatically attract to each other and coprecipitate. Then, MnO 2 /GO pasted on stainless steel mesh is electrochemically reduced by applying -1.1V to obtain MnO 2 /RGO nanohybrid. The structure and morphology of the MnO 2 and MnO 2 /RGO nanohybrid are examined by Raman spectroscopy, X-ray diffraction (XRD), atomic force microscopy (AFM), field emission-scanning electron microscopy (FE-SEM), energy dispersive spectroscopy (EDX), and thermal gravimetric analysis (TGA). The capacitive behaviors of MnO 2 and MnO 2 /RGO active materials on stainless steel meshes are investigated by cyclic voltammetry (CV), galvanostatic charge/discharge test and electrochemical impedance spectroscopy (EIS) by a three-electrode experimental setup in an aqueous solution of 0.5M sodium sulfate in the potential window of 0.0-1.0V. The electrochemical investigations reveal that MnO 2 /RGO exhibits high specific capacitance (C s ) of 375Fg -1 at current density of 1Ag -1 and good cycle stability (93% capacitance retention after 500 cycles at a scan rate of 200mVs -1 ). The obtained results give good prospect about the application of electrostatic coprecipitation method to prepare graphene/metal oxides nanohybrids as effective electrode materials for supercapacitors. Copyright © 2017 Elsevier B.V. All rights reserved.

A novel SWCNT-polyoxometalate nanohybrid material as an electrode for electrochemical supercapacitors

NASA Astrophysics Data System (ADS)

Chen, Han-Yi; Al-Oweini, Rami; Friedl, Jochen; Lee, Ching Yi; Li, Linlin; Kortz, Ulrich; Stimming, Ulrich; Srinivasan, Madhavi

2015-04-01

A novel nanohybrid material that combines single-walled carbon nanotubes (SWCNTs) with a polyoxometalate (TBA)5[PVV2MoVI10O40] (TBA-PV2Mo10, TBA: [(CH3(CH2)3)4N]+, tetra-n-butyl ammonium) is investigated for the first time as an electrode material for supercapacitors (SCs) in this study. The SWCNT-TBA-PV2Mo10 material has been prepared by a simple solution method which electrostatically attaches anionic [PV2Mo10O40]5- anions with organic TBA cations on the SWCNTs. The electrochemical performance of SWCNT-TBA-PV2Mo10 electrodes is studied in an acidic aqueous electrolyte (1 M H2SO4) by galvanostatic charge/discharge and cyclic voltammetry. In this SWCNT-TBA-PV2Mo10 nanohybrid material, TBA-PV2Mo10 provides redox activity while benefiting from the high electrical conductivity and high double-layer capacitance of the SWCNTs that improve both energy and power density. An assembled SWCNT-TBA-PV2Mo10 symmetric SC exhibits a 39% higher specific capacitance as compared to a symmetric SC employing only SWCNTs as electrode materials. Furthermore, the SWCNT-TBA-PV2Mo10 SC exhibits excellent cycling stability, retaining 95% of its specific capacitance after 6500 cycles.

A novel SWCNT-polyoxometalate nanohybrid material as an electrode for electrochemical supercapacitors.

PubMed

Chen, Han-Yi; Al-Oweini, Rami; Friedl, Jochen; Lee, Ching Yi; Li, Linlin; Kortz, Ulrich; Stimming, Ulrich; Srinivasan, Madhavi

2015-05-07

A novel nanohybrid material that combines single-walled carbon nanotubes (SWCNTs) with a polyoxometalate (TBA)5[PVMoO40] (TBA-PV2Mo10, TBA: [(CH3(CH2)3)4N](+), tetra-n-butyl ammonium) is investigated for the first time as an electrode material for supercapacitors (SCs) in this study. The SWCNT-TBA-PV2Mo10 material has been prepared by a simple solution method which electrostatically attaches anionic [PV2Mo10O40](5-) anions with organic TBA cations on the SWCNTs. The electrochemical performance of SWCNT-TBA-PV2Mo10 electrodes is studied in an acidic aqueous electrolyte (1 M H2SO4) by galvanostatic charge/discharge and cyclic voltammetry. In this SWCNT-TBA-PV2Mo10 nanohybrid material, TBA-PV2Mo10 provides redox activity while benefiting from the high electrical conductivity and high double-layer capacitance of the SWCNTs that improve both energy and power density. An assembled SWCNT-TBA-PV2Mo10 symmetric SC exhibits a 39% higher specific capacitance as compared to a symmetric SC employing only SWCNTs as electrode materials. Furthermore, the SWCNT-TBA-PV2Mo10 SC exhibits excellent cycling stability, retaining 95% of its specific capacitance after 6500 cycles.

Geometry in Biomimetic Network: Double Gyroid to Pseudo-Single Gyroid in Nanohybrid Materials

NASA Astrophysics Data System (ADS)

Hsueh, Han-Yu; Ho, Rong-Ming; Hung, Yu-Chueh; Ling, Yi-Chun; Hasegawa, Hirokazu

2013-03-01

Biological systems have developed delicately arranged micro- and architectures to produce striking optical effects since millions of years ago. Inspired by the textures of butterfly wings with single gyroid (SG) structure, herein, we aim to fabricate biocompatible and robust materials with SG-like structure in nanometer size so as to give new materials with unprecedented optical properties for applications. Biommicking from the biological photonic structures of butterfly wings, a double gyroid (DG) structure in nanometer size is obtained from the self-assembly of polystyrene-b-poly(L-lactide) (PS-PLLA). To acquire robust backbone networks, inorganic networks in polymer matrix are fabricated by using the hydrolyzed PS-PLLA with DG structure as a template for sol-gel reaction. Owing to the soft polymer matrix, two co-continuous inorganic networks embedded in the polymer matrix can be rearranged by thermal annealing at temperature above the glass transition of the polymer. Consequently, the rearrangement of these inorganic networks leads the formation of SG-like structure possessing unique nanohybrids with ordered texture. This unique nanomaterials with SG-like structure is referred as a pseudo-SG (p-SG) nanohybrids.

Biocide immobilized OMMT-carbon dot reduced Cu2O nanohybrid/hyperbranched epoxy nanocomposites: Mechanical, thermal, antimicrobial and optical properties.

PubMed

De, Bibekananda; Gupta, Kuldeep; Mandal, Manabendra; Karak, Niranjan

2015-11-01

The present work demonstrated a transparent thermosetting nanocomposite with antimicrobial and photoluminescence attributes. The nanocomposites are fabricated by incorporation of different wt.% (1, 2 and 3) of a biocide immobilized OMMT-carbon dot reduced Cu2O nanohybrid (MITH-NH) in the hyperbranched epoxy matrix. MITH-NH is obtained by immobilization of 2-methyl-4-isothiazolin-3-one hydrochloride (MITH) at room temperature using sonication on OMMT-carbon dot reduced Cu2O nanohybid. The nanohybrid is prepared by reduction of cupric acetate using carbon dot as the reducing agent in the presence of OMMT at 70°C. The significant improvements in tensile strength (~2 fold), elongation at break (3 fold), toughness (4 fold) and initial thermal degradation temperature (30°C) of the pristine hyperbranched epoxy system are achieved by incorporation of 3wt.% of MITH-NH in it. The nanocomposites exhibit strong antimicrobial activity against Staphylococcus aureus, Bacillus subtilis, Klebsiella pneumoniae and Pseudomonas aeruginosa bacteria and Candida albicans, a fungus. The nanocomposite also shows significant activity against biofilm formation compared to the pristine thermoset. Further, the nanocomposite films emit different colors on exposure of different wavelengths of UV light. The properties of these nanocomposites are also compared with the same nanohybrid without OMMT. Copyright © 2015. Published by Elsevier B.V.

C/TiO{sub 2} nanohybrids co-doped by N and their enhanced photocatalytic ability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ming Hai; Huang Hui; Pan Keming

2012-08-15

N-doping carbon-TiO{sub 2} nanohybrids (NCTs, nitrogen not only in situ doped carbon film but also doped TiO{sub 2} nanocrystals, and 5-10 nm TiO{sub 2} nanocrystals evenly dispersed on N-doping carbon film) have been successfully prepared by a mild, one-step approach. N-O-Ti chemical bonds between N-Carbon film and N-TiO{sub 2} nanoparticles were formed, and here, N-Carbon can not only sensitize and modify TiO{sub 2} nanocrystals surface, but also N can dope in the TiO{sub 2} nanocrystals. The as-prepared NCTs were investigated by X-ray photoelectron spectroscopy, TEM, FT-IR, electrochemistry method. It was demonstrated that the as-obtained NCTs have a large BET specificmore » surface area of 279.43 m{sup 2}/g. The NCTs show excellent photocatalytic abilities towards organic (Rhodamine B) and inorganic pollutant (K{sub 2}Cr{sub 2}O{sub 7}) degradation under visible light irradiation. This work provided a new approach for the high performance catalyst design towards new energy sources and environmental issues. - Graphical abstract: C/TiO{sub 2} nanohybrids co-doped by N with excellent photocatalytic performance were prepared. Highlights: Black-Right-Pointing-Pointer C/TiO{sub 2} nanohybrids (NCTs) co-doped by nitrogen (N) were prepared. Black-Right-Pointing-Pointer N was not only in situ doped in carbon film but also doped in TiO{sub 2} nanoparticles. Black-Right-Pointing-Pointer N-O-Ti chemical bonds were formed between C film and TiO{sub 2} nanoparticles. Black-Right-Pointing-Pointer NCTs exhibited excellent visible-light photocatalytic performance.« less

Dual nutraceutical nanohybrids of folic acid and calcium containing layered double hydroxides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Tae-Hyun; Oh, Jae-Min, E-mail: jaemin.oh@yonsei.ac.kr

2016-01-15

Dual nutraceutical nanohybrids consisting of organic nutrient, folic acid (FA), and mineral nutrient, calcium, were prepared based on layered double hydroxide (LDH) structure. Among various hybridization methods such as coprecipitation, ion exchange, solid phase reaction and exfoliation-reassembly, it was found that exfoliation-reassembly was the most effective in terms of intercalation of FA moiety between Ca-containing LDH layers. X-ray diffraction patterns and infrared spectra indicated that FA molecules were well stabilized in the interlayer space of LDHs through electrostatic interaction. From the atomic force and scanning electron microscopic studies, particle thickness of LDH was determined to be varied with tens, amore » few and again tens of nanometers in pristine, exfoliated and reassembled state, respectively, while preserving particle diameter. The result confirmed layer-by-layer hybrid structure of FA and LDHs was obtained by exfoliation-reassembly. Solid UV–vis spectra showed 2-dimensional molecular arrangement of FA moiety in hybrid, exhibiting slight red shift in n→π* and π→π* transition. The chemical formulae of FA intercalated Ca-containing LDH were determined to Ca{sub 1.30}Al(OH){sub 4.6}FA{sub 0.74}·3.33H{sub 2}O and Ca{sub 1.53}Fe(OH){sub 5.06}FA{sub 2.24}·9.94H{sub 2}O by inductively coupled plasma-atomic emission spectroscopy, high performance liquid chromatography and thermogravimetry, showing high nutraceutical content of FA and Ca. - Highlights: • We successfully intercalated FA molecules into Ca-containing LDHs. • Exfoliation-reassembly was proven to be the most effective. • The interaction between LDH and FA were studied by FT-IR and UV–vis spectra. • Thermal stability of FA were enhanced by electrostatic interaction with LDH layers.« less

Sugar loss and enzyme inhibition due to oligosaccharide accumulation during high solids-loading enzymatic hydrolysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xue, Saisi; Uppugundla, Nirmal; Bowman, Michael J.

Accumulation of recalcitrant oligosaccharides during high-solids loading enzymatic hydrolysis of cellulosic biomass reduces biofuel yields and increases processing costs for a cellulosic biorefinery. Recalcitrant oligosaccharides in AFEX-pretreated corn stover hydrolysate accumulate to the extent of about 18–25 % of the total soluble sugars in the hydrolysate and 12–18 % of the total polysaccharides in the inlet biomass (untreated), equivalent to a yield loss of about 7–9 kg of monomeric sugars per 100 kg of inlet dry biomass (untreated). These oligosaccharides represent a yield loss and also inhibit commercial hydrolytic enzymes, with both being serious bottlenecks for economical biofuel production frommore » cellulosic biomass. Very little is understood about the nature of these oligomers and why they are recalcitrant to commercial enzymes. This work presents a robust method for separating recalcitrant oligosaccharides from high solid loading hydrolysate in gramme quantities. Composition analysis, recalcitrance study and enzyme inhibition study were performed to understand their chemical nature. Results indicate that, oligosaccharide accumulation occurs during high solid loading enzymatic hydrolysis of corn stover (CS) irrespective of using different pretreated corn stover (dilute acid: DA, ionic liquids: IL, and ammonia fibre expansion: AFEX). The methodology for large-scale separation of recalcitrant oligosaccharides from 25 % solids-loading AFEXcorn stover hydrolysate using charcoal fractionation and size exclusion chromatography is reported for the first time. Oligosaccharides with higher degree of polymerization (DP) were recalcitrant towards commercial enzyme mixtures [Ctec2, Htec2 and Multifect pectinase (MP)] compared to lower DP oligosaccharides. Enzyme inhibition studies using processed substrates (Avicel and xylan) showed that low DP oligosaccharides also inhibit commercial enzymes. Addition of monomeric sugars to oligosaccharides increases the

Sugar loss and enzyme inhibition due to oligosaccharide accumulation during high solids-loading enzymatic hydrolysis

DOE PAGES

Xue, Saisi; Uppugundla, Nirmal; Bowman, Michael J.; ...

2015-11-26

Accumulation of recalcitrant oligosaccharides during high-solids loading enzymatic hydrolysis of cellulosic biomass reduces biofuel yields and increases processing costs for a cellulosic biorefinery. Recalcitrant oligosaccharides in AFEX-pretreated corn stover hydrolysate accumulate to the extent of about 18–25 % of the total soluble sugars in the hydrolysate and 12–18 % of the total polysaccharides in the inlet biomass (untreated), equivalent to a yield loss of about 7–9 kg of monomeric sugars per 100 kg of inlet dry biomass (untreated). These oligosaccharides represent a yield loss and also inhibit commercial hydrolytic enzymes, with both being serious bottlenecks for economical biofuel production frommore » cellulosic biomass. Very little is understood about the nature of these oligomers and why they are recalcitrant to commercial enzymes. This work presents a robust method for separating recalcitrant oligosaccharides from high solid loading hydrolysate in gramme quantities. Composition analysis, recalcitrance study and enzyme inhibition study were performed to understand their chemical nature. Results indicate that, oligosaccharide accumulation occurs during high solid loading enzymatic hydrolysis of corn stover (CS) irrespective of using different pretreated corn stover (dilute acid: DA, ionic liquids: IL, and ammonia fibre expansion: AFEX). The methodology for large-scale separation of recalcitrant oligosaccharides from 25 % solids-loading AFEXcorn stover hydrolysate using charcoal fractionation and size exclusion chromatography is reported for the first time. Oligosaccharides with higher degree of polymerization (DP) were recalcitrant towards commercial enzyme mixtures [Ctec2, Htec2 and Multifect pectinase (MP)] compared to lower DP oligosaccharides. Enzyme inhibition studies using processed substrates (Avicel and xylan) showed that low DP oligosaccharides also inhibit commercial enzymes. Addition of monomeric sugars to oligosaccharides increases the

Glioma Dual-Targeting Nanohybrid Protein Toxin Constructed by Intein-Mediated Site-Specific Ligation for Multistage Booster Delivery

PubMed Central

Chen, Yingzhi; Zhang, Meng; Jin, Hongyue; Li, Dongdong; Xu, Fan; Wu, Aihua; Wang, Jinyu; Huang, Yongzhuo

2017-01-01

Malignant glioma is one of the most untreatable cancers because of the formidable blood-brain barrier (BBB), through which few therapeutics can penetrate and reach the tumors. Biologics have been booming in cancer therapy in the past two decades, but their application in brain tumor has long been ignored due to the impermeable nature of BBB against effective delivery of biologics. Indeed, it is a long unsolved problem for brain delivery of macromolecular drugs, which becomes the Holy Grail in medical and pharmaceutical sciences. Even assisting by targeting ligands, protein brain delivery still remains challenging because of the synthesis difficulties of ligand-modified proteins. Herein, we propose a rocket-like, multistage booster delivery system of a protein toxin, trichosanthin (TCS), for antiglioma treatment. TCS is a ribosome-inactivating protein with the potent activity against various solid tumors but lack of specific action and cell penetration ability. To overcome the challenge of its poor druggability and site-specific modification, intein-mediated ligation was applied, by which a gelatinase-cleavable peptide and cell-penetrating peptide (CPP)-fused recombinant TCS toxin can be site-specifically conjugated to lactoferrin (LF), thus constructing a BBB-penetrating, gelatinase-activatable cell-penetrating nanohybrid TCS toxin. This nanohybrid TCS system is featured by the multistage booster strategy for glioma dual-targeting delivery. First, LF can target to the BBB-overexpressing low-density lipoprotein receptor-related protein-1 (LRP-1), and assist with BBB penetration. Second, once reaching the tumor site, the gelatinase-cleavable peptide acts as a separator responsive to the glioma-associated matrix metalloproteinases (MMPs), thus releasing to the CPP-fused toxin. Third, CPP mediates intratumoral and intracellular penetration of TCS toxin, thereby enhancing its antitumor activity. The BBB penetration and MMP-2-activability of this delivery system were

Photocatalytic degradation of organic contaminants under solar light using carbon dot/titanium dioxide nanohybrid, obtained through a facile approach

NASA Astrophysics Data System (ADS)

Hazarika, Deepshikha; Karak, Niranjan

2016-07-01

In the present study, a novel, simple and green method was developed to synthesize highly luminescent nitrogen containing carbon dot (CD) using carbon resources like bio-based citric acid and glycerol in the presence of cost free cow urine. The as-synthesized CD showed exciting wavelength dependent down- and up-conversion flourescence properties. To utilize the advantage of up-conversion flourescence, a nanohybrid (CD@TiO2) was synthesized from the above carbon resources and titanium butoxide through a facile one pot single step hydrothermal protocol. Nanomaterials like bare TiO2 and nanohybrid of TiO2 in presence of CD (CD/TiO2) were also synthesized for comparison purpose. The optical properties and structural characteristics of the prepared CD, bare TiO2, CD@TiO2 and CD/TiO2 were examined by Fourier transform infrared (FTIR), UV-vis and fluorescence spectroscopic, scanning electron microscopic (SEM), transmission electron microscopic (TEM) and X-ray diffraction (XRD) studies. The elemental compositions of bare CD and CD@TiO2 nanohybrid were obtained from EDX analyses. The poor crystalline nature and narrow distribution of spherical CD and anatase form of TiO2 were confirmed from XRD and TEM studies. Amongst the studied nanomaterials, CD@TiO2 exhibited the most promising photocatalytic degradation of organic pollutants like benzene and phenol as well as an anthrogenic pesticide under sunlight.

Integrating nanohybrid membranes of reduced graphene oxide: chitosan: silica sol gel with fiber optic SPR for caffeine detection

NASA Astrophysics Data System (ADS)

Kant, Ravi; Tabassum, Rana; Gupta, Banshi D.

2017-05-01

Caffeine is the most popular psychoactive drug consumed in the world for improving alertness and enhancing wakefulness. However, caffeine consumption beyond limits can result in lot of physiological complications in human beings. In this work, we report a novel detection scheme for caffeine integrating nanohybrid membranes of reduced graphene oxide (rGO) in chitosan modified silica sol gel (rGO: chitosan: silica sol gel) with fiber optic surface plasmon resonance. The chemically synthesized nanohybrid membrane forming the sensing route has been dip coated over silver coated unclad central portion of an optical fiber. The sensor works on the mechanism of modification of dielectric function of sensing layer on exposure to analyte solution which is manifested in terms of red shift in resonance wavelength. The concentration of rGO in polymer network of chitosan and silica sol gel and dipping time of the silver coated probe in the solution of nanohybrid membrane have been optimized to extricate the supreme performance of the sensor. The optimized sensing probe possesses a reasonably good sensitivity and follows an exponentially declining trend within the entire investigating range of caffeine concentration. The sensor boasts of an unparalleled limit of detection value of 1.994 nM and works well in concentration range of 0-500 nM with a response time of 16 s. The impeccable sensor methodology adopted in this work combining fiber optic SPR with nanotechnology furnishes a novel perspective for caffeine determination in commercial foodstuffs and biological fluids.

A randomized 10-year prospective follow-up of Class II nanohybrid and conventional hybrid resin composite restorations.

PubMed

van Dijken, Jan W V; Pallesen, Ulla

2014-12-01

To evaluate the 10-year durability of a nanohybrid resin composite in Class II restorations in a randomized controlled intraindividual comparison with its conventional hybrid resin composite predecessor. Each of 52 participants received at least two Class II restorations that were as similar as possible. The cavities were chosen at random to be restored with a nanohybrid resin composite (Excite/Tetric EvoCeram (TEC); n=61) and a conventional hybrid (Excite/Tetric Ceram (TC); n=61). The restorations were evaluated with slightly modified USPHS criteria at baseline and then annually for 10 years. The overall performance of the experimental restorations was tested after intra-individual comparison and their ranking was tested using Friedman's two-way ANOVA. The level of significance was set at 5%. Four patient drop-outs with 8 restorations (4TEC, 4TC) were registered during the follow-up. A prediction of the caries risk showed that 16 of the evaluated 52 patients were considered as high risk patients. In total, 22 restorations, 11 TEC (3 premolars, 8 molars) and 11 TC (3 premolars, 8 molars) restorations failed during the 10 years. The main reason for failure was secondary caries (50%). 63% of the recurrent caries lesions were found in high caries risk participants. The overall success rate at 10 years was 80.7%, with an annual failure rate of 1.9%. No statistically significant difference was found in the overall survival rate between the two investigated resin composites. The nanohybrid and the conventional hybrid resin composite showed good clinical effectiveness in extensive Class II restorations during the 10-year study.

Bioinspired Synthesis of Well-Ordered Layered Organic-Inorganic Nanohybrids: Mimicking the Natural Processing of Nacre by Mineralization of Block Copolymer Templates.

PubMed

Voet, Vincent S D; Kumar, Kamlesh; ten Brinke, Gerrit; Loos, Katja

2015-10-01

The unique mechanical performance of nacre, the pearly internal layer of shells, is highly dependent on its complex morphology. Inspired by the structure of nacre, the fabrication of well-ordered layered inorganic-organic nanohybrids is presented herein. This biomimetic approach includes the use of a block copolymer template, consisting of hydrophobic poly(vinylidene fluoride) (PVDF) lamellae covered with hydrophilic poly(methacrylic acid) (PMAA), to direct silica (SiO2 ) mineralization. The resulting PVDF/PMAA/SiO2 nanohybrid material resembles biogenic nacre with respect to its well-ordered and layered nanostructure, alternating organic-inorganic phases, macromolecular template, and mild processing conditions. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Shear-bond-strength of orthodontic brackets to aged nano-hybrid composite-resin surfaces using different surface preparation.

PubMed

Demirtas, Hatice Kubra; Akin, Mehmet; Ileri, Zehra; Basciftci, Faruk Ayhan

2015-01-01

The aim of this study was to evaluate the effects of different surface preparation methods on the shear bond strength (SBS) of orthodontic metal brackets to aged nano-hybrid resin composite surfaces in vitro. A total of 100 restorative composite resin discs, 6 mm in diameter and 3 mm thick, were obtained and treated with an ageing procedure. After ageing, the samples were randomly divided as follows according to surface preparation methods: (1)Control, (2)37% phosphoric acid gel, (3)Sandblasting, (4)Diamond bur, (5)Air-flow and 20 central incisor teeth were used for the control etched group. SBS test were applied on bonded metal brackets to all samples. SBS values and residual adhesives were evaluated. Analysis of variance showed a significant difference (p<0.001) between the groups. Sandblasted group had the highest SBS value (12.85 MPa) in experimental groups. The sandblasting surface treatment is recommended as an effective method of bonding orthodontic metal brackets to nano-hybrid composite resin surfaces.

A comparative evaluation of the staining capacity of microhybrid and nanohybrid resin-based composite to indian spices and food colorants: An In vitro study.

PubMed

Usha, Carounanidy; Rao, Sathyanarayanan Rama; George, Geena Mary

2018-01-01

Resin composite restorative materials can mimic the natural color and shade of the tooth. However, exogenous colorants from food and drinks can stain them due to adsorption. The influence of Indian food colorants and spices on resin composite restorations has not been evaluated extensively. This study aims to evaluate the staining capacity of microhybrid and nanohybrid resin-based composites, to saffron extract, tandoori powder, and turmeric powder. Forty samples of microhybrid (Kulzer Charisma) and nanohybrid (3M Filtek Z350) resin composites were prepared using an acrylic template of dimension 5 mm × 3 mm. They were randomly divided into four groups and immersed into solutions of saffron extract, tandoori powder, and turmeric powder. Distilled water was used as the control group. Color values (LFNx01, aFNx01, bFNx01) were measured by colorimeter using the CIE LFNx01aFNx01bFNx01 system before and after 72 h of immersion. Color differences ΔEFNx01ab were statistically analyzed. Two-way ANOVA and post-hoc Tukey (honest significant difference) test were done using IBM SPSS Statistics for Windows, Version 19.0. Armonk, NY: IBM Corp. : All the immersion media changed the color of the resin composites to varying degrees. However, turmeric solution showed the maximum mean color variation ΔEFNx01ab of 14.8 ± 2.57 in microhybrid resin composites and 16.8 ± 3.50 in nanohybrid resin composites. Microhybrid and nanohybrid resin composites tend to stain to Indian food colorants, especially to turmeric powder.

Dramatic improvement in water retention and proton conductivity in electrically aligned functionalized CNT/SPEEK nanohybrid PEM.

PubMed

Gahlot, Swati; Kulshrestha, Vaibhav

2015-01-14

Nanohybrid membranes of electrically aligned functionalized carbon nanotube f CNT with sulfonated poly ether ether ketone (SPEEK) have been successfully prepared by solution casting. Functionalization of CNTs was done through a carboxylation and sulfonation route. Further, a constant electric field (500 V·cm(-2)) has been applied to align CNTs in the same direction during the membrane drying process. All the membranes are characterized chemically, thermally, and mechanically by the means of FTIR, DSC, DMA, UTM, SEM, TEM, and AFM techniques. Intermolecular interactions between the components in hybrid membranes are established by FTIR. Physicochemical measurements were done to analyze membrane stability. Membranes are evaluated for proton conductivity (30-90 °C) and methanol crossover resistance to reveal their potential for direct methanol fuel cell application. Incorporation of f CNT reasonably increases the ion-exchange capacity, water retention, and proton conductivity while it reduces the methanol permeability. The maximum proton conductivity has been found in the S-sCNT-5 nanohybrid PEM with higher methanol crossover resistance. The prepared membranes can be also used for electrode material for fuel cells and batteries.

Thermo-responsive plasmonic nanohybrids with tunable optical properties

NASA Astrophysics Data System (ADS)

Zhang, Lingyu; Song, Gang

2017-10-01

In this paper, we study the temperature-dependent optical properties of gold-silver core-shell (Au@Ag) nanorods coated by a thermo-responsive polymer poly (N-isopropylacrylamide) (PNIPAM). The wavelength of the plasmonic resonant absorption of the nanohybrids changes with temperature due to the combination effects of the plasmon resonance of the core and the thermal response of the shell. Using effective medium theory, we find that with increase of temperature, the absorption peak red-shifts due to the competition effects from the changes of the thickness and the effective refractive index of the polymer shell. The working wavelength can be tuned by the aspect ratio of nanorods. Moreover, the temperature sensitivity of plasmon resonance increases with the increase of the aspect ratio. Our studies provide a proof-of-concept design of thermal responsive plasmonic smart material.

Preference of multi-walled carbon nanotube (MWCNT) to single-walled carbon nanotube (SWCNT) and activated carbon for preparing silica nanohybrid pickering emulsion for chemical enhanced oil recovery (C-EOR)

DOE Office of Scientific and Technical Information (OSTI.GOV)

AfzaliTabar, M.; Alaei, M., E-mail: alaiem@ripi.ir; Ranjineh Khojasteh, R.

The aim of this research was to determine the best nano hybrid that can be used as a Pickering emulsion Chemical Enhanced Oil Recovery (C-EOR). Therefore, we have prepared different carbon structures nano hybrids with SiO{sub 2} nano particles with different weight percent using sol-gel method. The as-prepared nano materials were characterized with X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM) and Thermal Gravimetric Analysis (TGA). Pickering emulsions of these nanohybrids were prepared at pH=7 in ambient temperature and with distilled water. Stability of the mentioned Pickering emulsions was controlled for one month. Emulsion phase morphology was investigated usingmore » optical microscopic imaging. Evaluation results demonstrated that the best sample is the 70% MWCNT/SiO{sub 2} nanohybrid. Stability of the selected nanohybrid (70% MWCNT/SiO{sub 2} nanohybrid) was investigated by alteration of salinity, pH and temperature. Results showed that the mentioned Pickering emulsion has very good stability at 0.1%, 1% salinity, moderate and high temperature (25 °C and 90 °C) and neutral and alkaline pH (7, 10) that is suitable for the oil reservoirs conditions. The effect of the related nano fluid on the wettability of carbonate rock was investigated by measuring the contact angle and interfacial tension. Results show that the nanofluid could significantly change the wettability of the carbonate rock from oil wet to water wet and can decrease the interfacial tension. Therefore, the 70% MWCNT/SiO{sub 2} nanohybrid Pickering emulsion can be used for Chemical Enhanced Oil Recovery (C-EOR).« less

Effect of different polishing systems on the surface roughness of nano-hybrid composites.

PubMed

Patel, Brijesh; Chhabra, Naveen; Jain, Disha

2016-01-01

The study aimed to investigate the influence of different polishing systems on the surface roughness of nano-hybrid composite resins. Different shapes of polishing systems are available according to the site of work. To minimize variability, a new system with single shape is developed that can be utilized in both anterior as well as posterior teeth. Seventy composite discs were fabricated using Teflon well (10 mm × 3 mm). Two main group of nano-hybrid composite Group I - Filtek Z350 and Group II - Tetric N-Ceram were used (n = 35 for each group). Both groups were further divided into four subgroups. Subgroup a - OneGloss (n = 10), Subgroup b - PoGo (n = 10), Subgroup c - Sof-Lex spiral (n = 10), Subgroup d - Mylar strip (control, n = 5). Samples were polished according to the manufacturer's recommendations. Surface roughness test was performed using contact profilometer. The obtained data were analyzed using the one-way analysis of variance test. Tetric N-Ceram produced smoother surfaces than Filtek Z350 (P < 0.05). Mylar strip and "PoGo" created equally smooth surfaces, while significantly rougher surfaces were obtained after applications of "Sof-Lex spiral" and "OneGloss" (P < 0.05). Polishing ability of Tetric N-Ceram is better than Filtek Z350 XT. "PoGo" seems to be a better polishing system than "OneGloss" and "Sof-Lex Spiral."

Phosphorescent quantum dots/doxorubicin nanohybrids based on photoinduced electron transfer for detection of DNA.

PubMed

Miao, Yanming; Zhang, Zhifeng; Gong, Yan; Yan, Guiqin

2014-09-15

MPA-capped Mn-doped ZnS QDs/DXR nanohybrids (MPA: 3-mercaptopropionic acid; QDs: quantum dots; DXR: cetyltrimethyl ammonium bromide) were constructed via photoinduced electron transfer (PIET) and then used as a room-temperature phosphorescence (RTP) probe for detection of DNA. DXR as a quencher will quench the RTP of Mn-doped ZnS QDs via PIET, thereby forming Mn-doped ZnS QDs/DXR nanohybrids and storing RTP. With the addition of DNA, it will be inserted into DXR and thus DXR will be competitively desorbed from the surface of Mn-doped ZnS QDs, thereby releasing the RTP of Mn-doped ZnS QDs. Based on this, a new method for DNA detection was built. The sensor for DNA has a detection limit of 0.039 mg L(-1) and a linear range from 0.1 to 14 mg L(-1). The present QDs-based RTP method does not need deoxidants or other inducers as required by conventional RTP detection methods, and avoids interference from autofluorescence and the scattering light of the matrix that are encountered in spectrofluorometry. Therefore, this method can be used to detect the DNA content in body fluid. Copyright © 2014 Elsevier B.V. All rights reserved.

Multifunctional PEG modified DOX loaded mesoporous silica nanoparticle@CuS nanohybrids as photo-thermal agent and thermal-triggered drug release vehicle for hepatocellular carcinoma treatment

NASA Astrophysics Data System (ADS)

Wu, Lingjie; Wu, Ming; Zeng, Yongyi; Zhang, Da; Zheng, Aixian; Liu, Xiaolong; Liu, Jingfeng

2015-01-01

The combination of a multi-therapeutic mode with a controlled fashion is a key improvement in nanomedicine. Here, we synthesized polyethylene glycol (PEG)-modified doxorubicin (DOX)-loaded mesoporous silica nanoparticle (MSN) @CuS nanohybrids as efficient drug delivery carriers, combined with photothermal therapy and chemotherapy to enhance the therapeutic efficacy on hepatocellular carcinoma (HCC). The physical properties of the nanohybrids were characterized by transmission electron microscopy (TEM), N2 adsorption and desorption experiments and by the Vis-NIR absorption spectra. The results showed that the doxorubicin could be stored in the inner pores of mesoporous silica nanoparticles; the CuS nanoparticles, which are coated on the surface of a mesoporous silica nanoparticle, could serve as efficient photothermal therapy (PTT) agents; the loaded drug release could be easily triggered by NIR irradiation. The combination of the PTT treatment with controlled chemotherapy could further enhance the cancer ablation ability compared to any of the single approaches alone. Hence, the reported PEG-modified DOX-loaded mesoporous silica nanoparticle@CuS nanohybrids might be very promising therapeutic agents for HCC treatment.

NiFe layered double hydroxide/reduced graphene oxide nanohybrid as an efficient bifunctional electrocatalyst for oxygen evolution and reduction reactions

NASA Astrophysics Data System (ADS)

Zhan, Tianrong; Zhang, Yumei; Liu, Xiaolin; Lu, SiSi; Hou, Wanguo

2016-11-01

Highly active and low-cost bifunctional electrocatalysts for oxygen evolution and reduction reactions (OER and ORR) hold a heart position for the renewable energy technologies such as metal-air batteries and fuel cells. Here, we reported the synthesis of NiFe layered double hydroxide/reduced graphene oxide (NiFe-LDH/rGO) nanohybrid via the facile solvothermal method followed by chemical reduction. The template role of surfactant and the hybridization of rGO supplied the NiFe-LDH/rGO catalyst with a porous nanostructure and an enhanced conductivity, favoring both mass transport and charge communication of electrocatalytic reactions. The NiFe-LDH/rGO composite not only displayed highly efficient OER activity in alkaline solution with a low onset overpotential of 240 mV, but also only needed an overpotential of 250 mV to reach the 10 mA cm-2 current density. The NiFe-LDH/rGO nanohybrid also offered excellent ORR catalytic activity with onset potential at 0.796 V in alkaline media. The rotating-disk and rotating-ring-disk electrodes both revealed that the ORR on NiFe-LDH/rGO mainly involved a direct four-electron reaction pathways accompanying part of the two-electron process. The excellent bifunctional activity of the NiFe-LDH/rGO nanohybrid could be attributed to the synergistic effects of rGO and NiFe-LDH components due to the strongly coupled interactions.

Efficient delivery of anticancer drug MTX through MTX-LDH nanohybrid system

NASA Astrophysics Data System (ADS)

Oh, Jae-Min; Park, Man; Kim, Sang-Tae; Jung, Jin-Young; Kang, Yong-Gu; Choy, Jin-Ho

2006-05-01

We have been successful to intercalate anticancer drug, methotrexate (MTX), into layered double hydroxides (LDHs), Mg2Al(OH)6(NO3)·0.1H2O, through conventional co-precipitation method. Layered double hydroxides (LDHs) are endowed with great potential for delivery vector, since their cationic layers lead to safe reservation of biofunctional molecules such as drug molecules or genes. And their ion exchangeability and solubility in acidic media (pH<4) give rise to the controlled release of drug molecules. Moreover, it has been partly confirmed that LDH itself is non-toxic and facilitate the cellular permeation. To check the toxicity of LDHs, the osteosarcoma cell culture lines (Saos-2 and MG-63) and the normal one (human fibroblast) were used for in vitro test. The anticancer efficacy of MTX intercalated LDHs (MTX-LDH nanohybrids) was also estimated in vitro by the bioassay such as MTT and BrdU (5-bromo-2-deoxyuridine) with the bone cancer cell culture lines (Saos-2 and MG-63). According to the toxicity test results, LDHs do not harm to both the normal and cancer cells upto the concentration of 500 ug/mL. The anticancer efficacy test for the MTX-LDH nanohybrids turn out to be much more effective in cell suppression compared to the MTX itself. According to the cell-line tests, the MTX-LDH shows same drug efficacy to the MTX itself in spite of the low concentration by ˜5000 times. Such a high cancer suppression effect of MTX-LDH hybrid is surely due to the excellent delivery efficiency of inorganic delivery vector, LDHs.

Influence of finish line on the marginal seal of nanohybrid composite crowns after periodontal scaling: a microleakage study.

PubMed

Angerame, D; De Biasi, M; Del Lupo, V; Bevilacqua, L; Zarone, F; Sorrentino, R

2015-10-01

The aim of the present microleakage study was to assess the sealing ability of nanohybrid composite crowns with different finish lines exposed to simulated mechanical periodontal treatment (SMPT). After sample size calculation (α=0.05; β=0.20; δ=1.0; σ=0.8), sixty extracted mandibular molars were divided into four groups (N.=15): G1, 90° shoulder; G2, beveled 90° shoulder; G3, 90° shoulder and SMPT; G4, beveled 90° shoulder and SMPT. Tooth preparations were carried out by means of diamond burs and Arkansas stones. The buildup of crowns was performed with a nanohybrid composite on master casts obtained after polyether impressions and crowns were cemented with self-adhesive cement. Groups G3 and G4 were subjected to the equivalent of five years of semestral mechanical periodontal scaling with Gracey curettes (2-mm long strokes, 5 N). Samples were immersed into a methylene blue supersaturated solution for 10 minutes. Microleakage was measured by stereomicroscopic observation of multiple sections of the samples and leakage data underwent statistical analysis with non-parametric tests. Marginal microleakage was 1.53±1.27% and 17.60±12.72% of the length of the adhesive interface in G1 and G2, respectively. SMPT reduced dye penetration (P<0.001) with G3 not leaking at all and G4 leaking along the 5.58±1.84% of the adhesive interface. The bevel preparation significantly worsened the marginal seal both in control and treated crowns (P<0.001). Microleakage of nanohybrid composite crowns increased by adding a bevel to a 90° shoulder preparation and diminished after SMPT.

Effect of organic solvents compared to sandblasting on the repair bond strength of nanohybrid and nanofilled composite resins.

PubMed

Brum, Rafael Torres; Vieira, Sergio; Freire, Andrea; Mazur, Rui Fernando; De Souza, Evelise Machado; Rached, Rodrigo Nunes

2017-01-01

This study evaluated the effect of different surface treatments on the repair bond strength of nanohybrid (Empress Direct) and nanofilled (Filtek Z350 XT) composite resins. A total of 120 specimens of each material (7.5 x 4.5 x 3 mm) were prepared and polished with SiC paper. Half of the specimens were kept in water for seven days and the other half for six months; they were then divided into six groups according to the type of surface treatment: negative control (no treatment), Al2O3sandblasted, liquid acetone, acetone gel, liquid alcohol and alcohol gel. Following application of the silane coupling agent and the adhesive system, composite resin cylinders were fabricated on the specimens and light cured (20 seconds). The same composite resins were used for the repair. Additionally, ten intact specimens of each composite resin (without repair) were prepared (positive control). The specimens were then loaded to failure in the microshear mode. Three additional specimens were fabricated in each group, and the surface treatments were analyzed by atomic force microscopy, energy-dispersive X-ray spectroscopy (EDS) and scanning electron microscopy (SEM). The nanofilled composite resin showed higher cohesive strength and repair bond strength than the nanohybrid composite resin. The aging process affected the repair bond strength of the nanofilled composite resin. Al2O3sandblasting was more efficient for the nanofilled composite resin and promoted greater surface roughness in both materials. The solvents demonstrated higher efficacy for the nanohybrid composite resin. The strengths resulting from the solvents were material dependent, and Al2O3sandblasting resulted in superior repair bond strength in both materials.

Effect of different polishing systems on the surface roughness of nano-hybrid composites

PubMed Central

Patel, Brijesh; Chhabra, Naveen; Jain, Disha

2016-01-01

Objective: The study aimed to investigate the influence of different polishing systems on the surface roughness of nano-hybrid composite resins. Background: Different shapes of polishing systems are available according to the site of work. To minimize variability, a new system with single shape is developed that can be utilized in both anterior as well as posterior teeth. Materials and Methods: Seventy composite discs were fabricated using Teflon well (10 mm × 3 mm). Two main group of nano-hybrid composite Group I — Filtek Z350 and Group II — Tetric N-Ceram were used (n = 35 for each group). Both groups were further divided into four subgroups. Subgroup a — OneGloss (n = 10), Subgroup b - PoGo (n = 10), Subgroup c — Sof-Lex spiral (n = 10), Subgroup d - Mylar strip (control, n = 5). Samples were polished according to the manufacturer's recommendations. Surface roughness test was performed using contact profilometer. The obtained data were analyzed using the one-way analysis of variance test. Result: Tetric N-Ceram produced smoother surfaces than Filtek Z350 (P < 0.05). Mylar strip and “PoGo” created equally smooth surfaces, while significantly rougher surfaces were obtained after applications of “Sof-Lex spiral” and “OneGloss” (P < 0.05). Conclusion: Polishing ability of Tetric N-Ceram is better than Filtek Z350 XT. “PoGo” seems to be a better polishing system than “OneGloss” and “Sof-Lex Spiral.” PMID:26957791

Polyallylamine-Rh nanosheet nanoassemblies-carbon nanotubes organic-inorganic nanohybrids: A electrocatalyst superior to Pt for the hydrogen evolution reaction

NASA Astrophysics Data System (ADS)

Bai, Juan; Xing, Shi-Hui; Zhu, Ying-Ying; Jiang, Jia-Xing; Zeng, Jing-Hui; Chen, Yu

2018-05-01

Rationally tailoring the surface/interface structures of noble metal nanostructures emerges as a highly efficient method for improving their electrocatalytic activity, selectivity, and long-term stability. Recently, hydrogen evolution reaction is attracting more and more attention due to the energy crisis and environment pollution. Herein, we successfully synthesize polyallylamine-functionalized rhodium nanosheet nanoassemblies-carbon nanotube nanohybrids via a facile one-pot hydrothermal method. Three-dimensionally branched rhodium nanosheet nanoassemblies are consisted of two dimensionally atomically thick ultrathin rhodium nanosheets. The as-prepared polyallylamine-functionalized rhodium nanosheet nanoassemblies-carbon nanotube nanohybrids show the excellent electrocatalytic activity for the hydrogen evolution reaction in acidic media, with a low onset reduction potential of -1 mV, a small overpotential of 5 mV at 10 mA cm-2, which is much superior to commercial platinum nanocrystals. Two dimensionally ultrathin morphology of rhodium nanosheet, particular rhodium-polyallylamine interface, and three-dimensionally networks induced by carbon nanotube are the key factors for the excellent hydrogen evolution reaction activity in acidic media.

Nanohybrids with Magnetic and Persistent Luminescence Properties for Cell Labeling, Tracking, In Vivo Real-Time Imaging, and Magnetic Vectorization.

PubMed

Teston, Eliott; Maldiney, Thomas; Marangon, Iris; Volatron, Jeanne; Lalatonne, Yoann; Motte, Laurence; Boisson-Vidal, Catherine; Autret, Gwennhael; Clément, Olivier; Scherman, Daniel; Gazeau, Florence; Richard, Cyrille

2018-04-01

Once injected into a living organism, cells diffuse or migrate around the initial injection point and become impossible to be visualized and tracked in vivo. The present work concerns the development of a new technique for therapeutic cell labeling and subsequent in vivo visualization and magnetic retention. It is hypothesized and subsequently demonstrated that nanohybrids made of persistent luminescence nanoparticles and ultrasmall superparamagnetic iron oxide nanoparticles incorporated into a silica matrix can be used as an effective nanoplatform to label therapeutic cells in a nontoxic way in order to dynamically track them in real-time in vitro and in living mice. As a proof-of-concept, it is shown that once injected, these labeled cells can be visualized and attracted in vivo using a magnet. This first step suggests that these nanohybrids represent efficient multifunctional nanoprobes for further imaging guided cell therapies development. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Silicon Oxycarbide/Carbon Nanohybrids with Tiny Silicon Oxycarbide Particles Embedded in Free Carbon Matrix Based on Photoactive Dental Methacrylates.

PubMed

Wang, Meimei; Xia, Yonggao; Wang, Xiaoyan; Xiao, Ying; Liu, Rui; Wu, Qiang; Qiu, Bao; Metwalli, Ezzeldin; Xia, Senlin; Yao, Yuan; Chen, Guoxin; Liu, Yan; Liu, Zhaoping; Meng, Jian-Qiang; Yang, Zhaohui; Sun, Ling-Dong; Yan, Chun-Hua; Müller-Buschbaum, Peter; Pan, Jing; Cheng, Ya-Jun

2016-06-08

A new facile scalable method has been developed to synthesize silicon oxycarbide (SiOC)/carbon nanohybrids using difunctional dental methacrylate monomers as solvent and carbon source and the silane coupling agent as the precursor for SiOC. The content (from 100% to 40% by mass) and structure (ratio of disordered carbon over ordered carbon) of the free carbon matrix have been systematically tuned by varying the mass ratio of methacryloxypropyltrimethoxysilane (MPTMS) over the total mass of the resin monomers from 0.0 to 6.0. Compared to the bare carbon anode, the introduction of MPTMS significantly improves the electrochemical performance as a lithium-ion battery anode. The initial and cycled discharge/charge capacities of the SiOC/C nanohybrid anodes reach maximum with the MPTMS ratio of 0.50, which displays very good rate performance as well. Detailed structures and electrochemical performance as lithium-ion battery anodes have been systematically investigated. The structure-property correlation and corresponding mechanism have been discussed.

A nanohybrid of platinum nanoparticles-porous ZnO-hemin with electrocatalytic activity to construct an amplified immunosensor for detection of influenza.

PubMed

Yang, Zhe-Han; Zhuo, Ying; Yuan, Ruo; Chai, Ya-Qin

2016-04-15

In this work, a nanohybrid of platinum nanoparticles-porous ZnO spheres-hemin (Pt-pZnO-hemin) was synthesized for construction of alkaline phosphatase-based immunosensor for detection of influenza. Briefly, porous ZnO spheres (pZnO) were prepared using soluble starches as the capping agent, followed by surface functionalization of platinum nanoparticles via a hydrothermal method (Pt-pZnO). Then, hemin with carboxylic functionality was spontaneously adsorbed onto Pt-pZnO by ester-like binding between carboxylic group of hemin and ZnO. Compared with platinum nanoparticles and hemin, the resulting Pt-pZnO-hemin nanohybrid showed more excellent electrocatalysis activity toward 1-naphthol (1-NP). Taking advantage of the Pt-pZnO-hemin, we have developed an amplified electrochemical immunosensor based on in situ generation of redox probe by alkaline phosphatase (ALP) and Pt-pZnO-hemin as signal enhancer. Herein, electrochemically active 1-NP was generated by enzymatic hydrolysis of inactive 1-naphthyl phosphate by ALP, then Pt-pZnO-hemin was used as catalyst to catalytically oxidize 1-NP, resulting in electrochemical signal amplification. Furthermore, in comparison with other nanomaterials including Au-pZnO, Pt-pZnO and Au-pZnO-hemin, the excellent catalytical property of Pt-pZnO-hemin make it a promising nanohybrid material for ALP-based immunosensor for signal amplification. Copyright © 2015. Published by Elsevier B.V.

Nanohybrid conjugated polyelectrolytes: highly photostable and ultrabright nanoparticles.

PubMed

Darwish, Ghinwa H; Karam, Pierre

2015-10-07

We present a general and straightforward one-step approach to enhance the photophysical properties of conjugated polyelectrolytes. Upon complexation with an amphiphilic polymer (polyvinylpyrrolidone), an anionic conjugated polyelectrolyte (poly[5-methoxy-2-(3-sulfopropoxy)-1,4-phenylenevinylene]) was prepared into small nanoparticles with exceptional photostability and brightness. The polymer fluorescence intensity was enhanced by 23 -fold and could be easily tuned by changing the order of addition. Single molecule experiments revealed a complete suppression of blinking. In addition, after only losing 18% of the original intensity, a remarkable amount of photons were emitted per particle (∼10(9), on average). This number is many folds greater than popular organic fluorescent dyes. We believe that an intimate contact between the two polymers is shielding the conjugated polyelectrolyte from the destructive photooxidation. The prepared nanohybrid particles will prove instrumental in single particle based fluorescent assays and can serve as a probe for the current state-of-the-art bioimaging fluorescence techniques.

Repair bond strength of nanohybrid composite resins with a universal adhesive

PubMed Central

Altinci, Pinar; Mutluay, Murat; Tezvergil-Mutluay, Arzu

2018-01-01

Abstract Objective: To investigate the repair bond strength of fresh and aged nanohybrid and hybrid composite resins using a universal adhesive (UA). Materials and methods: Fresh and aged substrates were prepared using two nanohybrid (Venus Pearl, Heraus Kulzer; Filtek Supreme XTE, 3 M ESPE) and one hybrid (Z100, 3 M ESPE) composite resin, and randomly assigned to different surface treatments: (1) no treatment (control), (2) surface roughening with 320-grit (SR), (3) SR + UA (iBOND, Heraus Kulzer), (4) SR + Silane (Signum, Ceramic Bond I, Heraeus Kulzer) + UA, (5) SR + Sandblasting (CoJet, 3 M ESPE) + Silane + UA. After surface treatment, fresh composite resin was added to the substrates at 2 mm layer increments to a height of 5 mm, and light cured. Restored specimens were water-stored for 24 h and sectioned to obtain 1.0 × 1.0 mm beams (n = 12), and were either water-stored for 24 h at 37 °C, or water-stored for 24 h, and then thermocycled for 6000 cycles before microtensile bond strength (µTBS) testing. Data were analyzed with ANOVA and Tukey’s HSD tests (p = .05). Results: Combined treatment of SR, sandblasting, silane and UA provided repair bond strength values comparable to the cohesive strength of each tested resin material (p < .05). Thermocycling significantly reduced the cohesive strength of the composite resins upto 65% (p < .05). Repair bond strengths of UA-treated groups were more stable under thermocycling. Conclusions: Universal adhesive application is a reliable method for composite repair. Sandblasting and silane application slightly increases the repair strength for all substrate types. PMID:29250576

Repair bond strength of nanohybrid composite resins with a universal adhesive.

PubMed

Altinci, Pinar; Mutluay, Murat; Tezvergil-Mutluay, Arzu

2018-01-01

Objective: To investigate the repair bond strength of fresh and aged nanohybrid and hybrid composite resins using a universal adhesive (UA). Materials and methods: Fresh and aged substrates were prepared using two nanohybrid (Venus Pearl, Heraus Kulzer; Filtek Supreme XTE, 3 M ESPE) and one hybrid (Z100, 3 M ESPE) composite resin, and randomly assigned to different surface treatments: (1) no treatment (control), (2) surface roughening with 320-grit (SR), (3) SR + UA (iBOND, Heraus Kulzer), (4) SR + Silane (Signum, Ceramic Bond I, Heraeus Kulzer) + UA, (5) SR + Sandblasting (CoJet, 3 M ESPE) + Silane + UA. After surface treatment, fresh composite resin was added to the substrates at 2 mm layer increments to a height of 5 mm, and light cured. Restored specimens were water-stored for 24 h and sectioned to obtain 1.0 × 1.0 mm beams ( n  = 12), and were either water-stored for 24 h at 37 °C, or water-stored for 24 h, and then thermocycled for 6000 cycles before microtensile bond strength (µTBS) testing. Data were analyzed with ANOVA and Tukey's HSD tests ( p  = .05). Results: Combined treatment of SR, sandblasting, silane and UA provided repair bond strength values comparable to the cohesive strength of each tested resin material ( p  < .05). Thermocycling significantly reduced the cohesive strength of the composite resins upto 65% ( p  < .05). Repair bond strengths of UA-treated groups were more stable under thermocycling. Conclusions: Universal adhesive application is a reliable method for composite repair. Sandblasting and silane application slightly increases the repair strength for all substrate types.

Nanohybrids of magnetic iron-oxide particles in hydrophobic organoclays for oil recovery.

PubMed

Hsu, Ru-Siou; Chang, Wen-Hsin; Lin, Jiang-Jen

2010-05-01

Nanohybrids with magnetic iron-oxide nanoparticles (FeNPs) embedded in the multilayered silicate clay were synthesized by in situ Fe(2+)/Fe(3+) coprecipitation. The natural clay, sodium montmorillonite (Na(+)-MMT), was first modified with hydrophobic poly(oxypropylene)amine salts (POP at 2000 and 4000 g/mol M(w)). The two POP-intercalated organoclays, with a silicate interlayer expansion from 1.2 to 5.2 and 9.2 nm, respectively, are suitable for embedding FeNPs. The presence of POP organics in layered structure created the space for intercalating with FeNPs of 2-4 nm in diameter, observed by transmission electronic microscope. The synthesized nanohybrids of POP4000/MMT-FeNP was composed of 17% iron oxide and 51 wt % POP within the silicate basal spacing of 5.0 nm. In contrast, the lower molecular weight of POP2000 intercalated MMT failed to encapsulate FeNPs in a significant amount, but resulting a "crowding-out effect" that caused the silicate interlayer space to shrink from 5.2 to 1.8 nm because of the replacement of the POP salt by Fe(2+)/Fe(3+) ions. The synthesis required the use of high molecular weight POP4000 and low temperatures (<4 degrees C) for a better dispersion in the reaction medium. The presence of POP in the layered silicate facilitated a homogeneous POP/MMT in water, associating with Fe(2+)/Fe(3+) ions and spatially accommodating for the subsequently generated FeNPs. The synthesized nanostructure consisting of POP and FeNP could be used as a pollutant remedy because of its ability to adsorbing crude oil and it is maneuverable under an applied magnetism.

Novel nanohybrids of cobalt(III) Schiff base complexes and clay: synthesis and structural determinations.

PubMed

Kianfar, Ali Hossein; Mahmood, Wan Ahmad Kamil; Dinari, Mohammad; Azarian, Mohammad Hossein; Khafri, Fatemeh Zare

2014-06-05

The [Co(Me(2)Salen)(PBu(3))(OH(2))]BF4 and [Co(Me(2)Salen)(PPh(3))(Solv)]BF(4), complexes were synthesized and characterized by FT-IR, UV-Vis, (1)H NMR spectroscopy and elemental analysis techniques. The coordination geometry of [Co(Me(2)Salen)(PPh(3))(H(2)O)]BF(4) was determined by X-ray crystallography. It has been found that the complex is containing [Co(Me(2)Salen)(PPh(3))(H(2)O)]BF(4) and [Co(Me(2)Salen)(PPh(3))(EtOH)]BF(4) hexacoordinate species in the solid state. Cobalt atom exhibits a distorted octahedral geometry and the Me(2)Salen ligand has the N2O2 coordinated environment in the equatorial plane. The [Co(Me(2)Salen)(PPh(3))(H(2)O)]BF(4) complex shows a dimeric structure via hydrogen bonding between the phenolate oxygen and hydrogens of coordinated H2O molecule. These complexes were incorporated into Montmorillonite-K10 nanoclay. The modified clays were identified by FT-IR, XRD, EDX, TGA/DTA, SEM and TEM techniques. According to the XRD results of the new nanohybrid materials, the Schiff base complexes are intercalated in the interlayer spaces of the clay. SEM and TEM micrographs show that the resulting hybrid nanomaterials have layer structures. Also, TGA/DTG results show that the intercalation reaction was taken place successfully. Copyright © 2014. Published by Elsevier B.V.

Facile synthesis of a conjugation-grafted-TiO2 nanohybrid with enhanced visible-light photocatalytic properties from nanotube titanic acid precursors

NASA Astrophysics Data System (ADS)

Guo, Yanru; Zhang, Min; Zhang, Zhihua; Li, Qiuye; Yang, Jianjun

2016-08-01

A conjugation-grafted-TiO2 nanohybrid was synthesized by chemically grafting conjugated structures on the surface of nanotube titanic acid (NTA) precursor-based TiO2 through the controlled thermal degradation of a coacervated polymer layer of polyvinyl alcohol (PVA). The interfacial interactions between the NTA precursor-based TiO2 and conjugated structures were characterized using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Moreover, the effects of the NTA's pretreatment temperature and the weight ratio of NTA to PVA on the photocatalytic degradation of methyl orange were also investigated. A higher NTA pretreatment temperature and a lower NTA to PVA weight ratio were found to enhance photogenerated electron-hole separation efficiency and photocatalytic activity. Moreover, the conjugation-grafted-TiO2 nanohybrid synthesized from the NTA precursor displayed a much higher visible-light photocatalytic activity than that of the sample obtained from the P25 precursor. The origin of the enhanced photocatalytic activity under visible-light irradiation is also discussed in detail.

Avatar DNA Nanohybrid System in Chip-on-a-Phone

NASA Astrophysics Data System (ADS)

Park, Dae-Hwan; Han, Chang Jo; Shul, Yong-Gun; Choy, Jin-Ho

2014-05-01

Long admired for informational role and recognition function in multidisciplinary science, DNA nanohybrids have been emerging as ideal materials for molecular nanotechnology and genetic information code. Here, we designed an optical machine-readable DNA icon on microarray, Avatar DNA, for automatic identification and data capture such as Quick Response and ColorZip codes. Avatar icon is made of telepathic DNA-DNA hybrids inscribed on chips, which can be identified by camera of smartphone with application software. Information encoded in base-sequences can be accessed by connecting an off-line icon to an on-line web-server network to provide message, index, or URL from database library. Avatar DNA is then converged with nano-bio-info-cogno science: each building block stands for inorganic nanosheets, nucleotides, digits, and pixels. This convergence could address item-level identification that strengthens supply-chain security for drug counterfeits. It can, therefore, provide molecular-level vision through mobile network to coordinate and integrate data management channels for visual detection and recording.

Avatar DNA Nanohybrid System in Chip-on-a-Phone

PubMed Central

Park, Dae-Hwan; Han, Chang Jo; Shul, Yong-Gun; Choy, Jin-Ho

2014-01-01

Long admired for informational role and recognition function in multidisciplinary science, DNA nanohybrids have been emerging as ideal materials for molecular nanotechnology and genetic information code. Here, we designed an optical machine-readable DNA icon on microarray, Avatar DNA, for automatic identification and data capture such as Quick Response and ColorZip codes. Avatar icon is made of telepathic DNA-DNA hybrids inscribed on chips, which can be identified by camera of smartphone with application software. Information encoded in base-sequences can be accessed by connecting an off-line icon to an on-line web-server network to provide message, index, or URL from database library. Avatar DNA is then converged with nano-bio-info-cogno science: each building block stands for inorganic nanosheets, nucleotides, digits, and pixels. This convergence could address item-level identification that strengthens supply-chain security for drug counterfeits. It can, therefore, provide molecular-level vision through mobile network to coordinate and integrate data management channels for visual detection and recording. PMID:24824876

Modeling of anaerobic degradation of solid slaughterhouse waste: inhibition effects of long-chain fatty acids or ammonia.

PubMed

Lokshina, L Y; Vavilin, V A; Salminen, E; Rintala, J

2003-01-01

The anaerobic bioconversion of solid poultry slaughterhouse wastes was kinetically investigated. The modified version of simulation model was applied for description of experimental data in mesophilic laboratory digester and assays. Additionally, stages of formation and consumption of long chain fatty acids (LCFA) were included in the model. Batch data on volatile solids, ammonium, acetate, butyrate, propionate, LCFA concentrations, pH level, cumulative volume, and methane partial pressure were used for model calibration. As a reference, the model was used to describe digestion of solid sorted household waste. Simulation results showed that an inhibition of polymer hydrolysis by volatile fatty acids and acetogenesis by NH3 or LCFA could be responsible for the complex system dynamics during degradation of lipid- and protein-rich wastes.

Evaluate the ability of PVP to inhibit crystallization of amorphous solid dispersions by density functional theory and experimental verify.

PubMed

Wang, Bing; Wang, Dandan; Zhao, Shan; Huang, Xiaobin; Zhang, Jianbin; Lv, Yan; Liu, Xiaocen; Lv, Guojun; Ma, Xiaojun

2017-01-01

In this study, we used density functional theory (DFT) to predict polymer-drug interactions, and then evaluated the ability of poly (vinyl pyrrolidone) (PVP) to inhibit crystallization of amorphous solid dispersions by experimental-verification. Solid dispersions of PVP/resveratrol (Res) and PVP/griseofulvin (Gri) were adopted for evaluating the ability of PVP to inhibit crystallization. The density functional theory (DFT) with the B3LYP was used to calculate polymer-drug and drug-drug interactions. Fourier transform infrared spectroscopy (FTIR) was used to confirm hydrogen bonding interactions. Polymer-drug miscibility and drug crystallinity were characterized by the modulated differential scanning calorimetry (MDSC) and X-ray powder diffraction (XRD). The release profiles were studied to investigate the dissolution advantage. DFT results indicated that E PVP-Res >E Res-Res (E: represents hydrogen bonding energy). A strong interaction was formed between PVP and Res. In addition, Fourier transform infrared spectroscopy (FTIR) analysis showed hydrogen bonding formed between PVP and Res, but not between PVP and Gri. MDSC and XRD results suggested that 70-90wt% PVP/Res and PVP/Gri solid dispersions formed amorphous solid dispersions (ASDs). Under the accelerated testing condition, PVP/Res dispersions with higher miscibility quantified as 90/10wt% were more stable than PVP/Gri dispersions. The cumulative dissolution rate of 90wt% PVP/Res dispersions still kept high after 90days storage due to the strong interaction. However, the cumulative dissolution rate of PVP/Gri solid dispersions significantly dropped because of the recrystallization of Gri. Copyright © 2016 Elsevier B.V. All rights reserved.

Characterization of Compounds with Tumor-Cell Proliferation Inhibition Activity from Mushroom (Phellinus baumii) Mycelia Produced by Solid-State Fermentation.

PubMed

Zhang, Henan; Shao, Qian; Wang, Wenhan; Zhang, Jingsong; Zhang, Zhong; Liu, Yanfang; Yang, Yan

2017-04-27

The inhibition of tumor-cell proliferationbyan organicsolvent extract from the solid-state fermentation of Phellinus baumii mycelia inoculated in rice medium was investigated in vitro. The active compounds inhibiting tumor-cell proliferation were characterized. Results revealed that all (petroleum ether, chloroform, ethyl acetate, and butanol) fractions inhibited tumor-cell proliferation in a dose-dependent fashion. The ethyl acetate extract had the highest inhibitory effecton tumor-cell proliferation, and the butanol fraction had the lowest. Six compounds were isolated and purified from the ethyl acetate extract of P. baumii mycelia by the tandem application of silica-gel column chromatography (SGCC), high-speed countercurrent chromatography (HSCCC), and preparative HPLC. These compounds were identified by NMR and electrospray ionization-mass spectrometry (ESI-MS) spectroscopic methods as ergosterol (RF1), ergosta-7,22-dien-3β-yl pentadecanoate (RF3), 3,4-dihydroxy benzaldehyde(RF6), inoscavinA (RF7), baicalein(RF10), and 24-ethylcholesta-5,22-dien-3β-ol (RF13). To further clarify the activity of these compounds, the cell-proliferation-inhibition tests of these compounds on various tumor cells were carried out and evaluatedin vitro. Results suggested that compounds RF6, RF7, and RF10 had potent inhibition effects on the proliferation of a series of tumor cell lines, including K562, L1210, SW620, HepG2, LNCaP, and MCF-7cells. These findings indicated that P. baumii mycelia produced by solid-state fermentation in rice canbe used to obtain active compounds with the ability to inhibittumor-cell proliferation.

Biocompatible magnetite/gold nanohybrid contrast agents via green chemistry for MRI and CT bioimaging.

PubMed

Narayanan, Sreeja; Sathy, Binulal N; Mony, Ullas; Koyakutty, Manzoor; Nair, Shantikumar V; Menon, Deepthy

2012-01-01

Magnetite/gold (Fe(3)O(4)/Au) hybrid nanoparticles were synthesized from a single iron precursor (ferric chloride) through a green chemistry route using grape seed proanthocyanidin as the reducing agent. Structural and physicochemical characterization proved the nanohybrid to be crystalline, with spherical morphology and size ~35 nm. Magnetic resonance imaging and magnetization studies revealed that the Fe(3)O(4) component of the hybrid provided superparamagnetism, with dark T(2) contrast and high relaxivity (124.2 ± 3.02 mM(-1) s(-1)). Phantom computed tomographic imaging demonstrated good X-ray contrast, which can be attributed to the presence of the nanogold component in the hybrid. Considering the potential application of this bimodal nanoconstruct for stem cell tracking and imaging, we have conducted compatibility studies on human Mesenchymal Stem Cells (hMSCs), wherein cell viability, apoptosis, and intracellular reactive oxygen species (ROS) generation due to the particle-cell interaction were asessed. It was noted that the material showed good biocompatibility even for high concentrations of 500 μg/mL and up to 48 h incubation, with no apoptotic signals or ROS generation. Cellular uptake of the nanomaterial was visualized using confocal microscopy and prussian blue staining. The presence of the nanohybrids were clearly visualized in the intracytoplasmic region of the cell, which is desirable for efficient imaging of stem cells in addition to the cytocompatible nature of the hybrids. Our work is a good demonstrative example of the use of green aqueous chemistry through the employment of phytochemicals for the room temperature synthesis of complex hybrid nanomaterials with multimodal functionalities. © 2011 American Chemical Society

Efficient visible-light photocatalytic and enhanced photocorrosion inhibition of Ag2WO4 decorated MoS2 nanosheets

NASA Astrophysics Data System (ADS)

Thangavel, Sakthivel; Thangavel, Srinivas; Raghavan, Nivea; Alagu, Raja; Venugopal, Gunasekaran

2017-11-01

The use of two-dimensional nanomaterials as co-catalysts in the photodegradation of toxic compounds using light irradiation is an attractive ecofriendly process. In this study, we prepared a novel MoS2/Ag2WO4 nanohybrid via a one-step hydrothermal approach and the photocatalytic properties were investigated by the degradation of methyl-orange under stimulated irradiation. The nanohybrid exhibits enhanced efficiency in dye degradation compared to the bare Ag2WO4 nanorods; the same has been evidently confirmed with UV-visible spectra and total organic carbon removal analysis. The pseudo-first order rate constant of the nanohybrid is nearly 1.8 fold higher than that of the bare Ag2WO4 nanorods. With the aid of classical radical quenching and photoluminescence spectral analysis, a reasonable mechanism has been derived for the addition of MoS2 to nanohybrids to enhance the photocatalytic efficiency. MoS2 prevents photocorrosion of Ag2WO4 and also diminishes the number of photogenerated electron-hole recombination. Our findings could provide new insights in understanding the mechanism of the MoS2/Ag2WO4 nanohybrid as an efficient photocatalyst suitable for waste-water treatment and remedial applications.

Sol-gel, One Technology by Produced Nanohybrid with Anticorrosive Properties

NASA Astrophysics Data System (ADS)

Hernández-Padrón, Genoveva; García-Garduño, Margarita V.

The evolution of nanotechnology has been allowed modify the material properties since of chemical architecture. In this work, we development nanohybrids sol-gel process, silica particles are incorporated a functionalized polymer resin (type epoxy and/or phenolic) with carboxylic groups. When the metallic plate is coating formed film ceramic glass. The incorporation this particles into to polymeric matrix, allowed to obtain performance corrosive properties. The structural characteristics of the different materials prepared, phenolic resin (RF), the resin functionalized (RFF) and its corresponding hybrids (RF-SiO2 and RFF- SiO2), were studied by infrared spectroscopy and morphological changes were analyzed by scanning electron microscopy. Then cooper plates were coated with these materials to evaluate their corrosion performance. The corrosion performance evaluation for each of these coatings RF, RFF, RE- SiO2 and RFF- SiO2 were determined by the following tests: a misty saline chamber operated under accelerated corrosive conditions for corrosion advance measurement, abrasion and adhesion.

Facile fabrication and characterization of a novel oral pH-sensitive drug delivery system based on CMC hydrogel and HNT-AT nanohybrid.

PubMed

Hossieni-Aghdam, Seyed Jamal; Foroughi-Nia, Behrouz; Zare-Akbari, Zhila; Mojarad-Jabali, Solmaz; Motasadizadeh, Hamidreza; Farhadnejad, Hassan

2018-02-01

The main aim of the present study was to design pH-sensitive bionanocomposite hydrogel beads based on CMC and HNT-AT nanohybrid and evaluate whether prepared bionanocomposite beads have the potential to be used in drug delivery applications. Atenolol (AT), as a model drug, was incorporated into the lumen of HA nanotubes via the co-precipitation technique. HNT/AT nanohybrid and CMC/HNT-AT beads were characterized via XRD, SEM, TGA, and FT-IR techniques. Drug loading and encapsulation efficiency was found to be high for CMC/HNT3 beads. Moreover, the swelling and drug release properties of the prepared CMC/HA-AT beads were investigated, and showed a pH sensitive swelling behavior with maximum its content at pH 6.8. Also, it was found that the swelling ratio of CMC/HNT beads was lower than that of pristine CMC beads. Drug release behavior of CMC/HNT-AT bionanocomposite hydrogel beads were investigated. A more sustained and controlled drug releases were observed for CMC/HNT-AT beads. Copyright © 2017 Elsevier B.V. All rights reserved.

Integrin α(V)β(3)-targeted magnetic nanohybrids with enhanced antitumor efficacy, cell cycle arrest ability, and encouraging anti-cell-migration activity.

PubMed

Ding, Guo-Bin; Wang, Yan; Guo, Yi; Xu, Li

2014-10-08

Organic/inorganic nanohybrids, which integrate advantages of the biocompatibility of organic polymers and diversified functionalities of inorganic nanoparticles, have been extensively investigated in recent years. Herein, we report the construction of arginine-glycine-aspartic acid-cysteine (RGDC) tetrapeptide functionalized and 10-hydroxycamptothecin (HCPT)-encapsulated magnetic nanohybrids (RFHEMNs) for integrin αVβ3-targeted drug delivery. The obtained RFHEMNs were near-spherical in shape with a homogeneous size about 50 nm, and exhibited a superparamagnetic behavior. In vitro drug release study showed a sustained and pH-dependent release profile. Cell viability tests revealed that RFHEMNs displayed a significant enhancement of cytotoxicity against αVβ3-overexpressing A549 cells, as compared to free HCPT and nontargeting micelles. Flow cytometry analysis indicated that this cytotoxic effect was associated with dose-dependent S phase arrest. Finally, RFHEMNs exerted encouraging anti-cell-migration activity as determined by an in vitro wound-healing assay and a transwell assay. Overall, we envision that this tumor-targeting nanoscale drug delivery system may be of great application potential in chemotherapy of primary tumor and their metastases.

General Solvent-dependent Strategy toward Enhanced Oxygen Reduction Reaction in Graphene/Metal Oxide Nanohybrids: Effects of Nitrogen-containing Solvent

NASA Astrophysics Data System (ADS)

Kao, Wei-Yao; Chen, Wei-Quan; Chiu, Yu-Hsiang; Ho, Yu-Hsuan; Chen, Chun-Hu

2016-11-01

A general solvent-dependent protocol directly influencing the oxygen reduction reaction (ORR) in metal oxide/graphene nanohybrids has been demonstrated. We conducted the two-step synthesis of cobalt oxide/N-doped graphene nanohybrids (CNG) with solvents of water, ethanol, and dimethylformamide (DMF), representing tree typical categories of aqueous, polar organic, and organic N-containing solvents commonly adopted for graphene nanocomposites preparation. The superior ORR performance of the DMF-hybrids can be attributed to the high nitrogen-doping, aggregation-free hybridization, and unique graphene porous structures. As DMF is the more effective N-source, the spectroscopic results support a catalytic nitrogenation potentially mediated by cobalt-DMF coordination complexes. The wide-distribution of porosity (covering micro-, meso-, to macro-pore) and micron-void assembly of graphene may further enhance the diffusion kinetics for ORR. As the results, CNG by DMF-synthesis exhibits the high ORR activities close to Pt/C (i.e. only 8 mV difference of half-wave potential with electron transfer number of 3.96) with the better durability in the alkaline condition. Additional graphene hybrids comprised of iron and manganese oxides also show the superior ORR activities by DMF-synthesis, confirming the general solvent-dependent protocol to achieve enhanced ORR activities.

General Solvent-dependent Strategy toward Enhanced Oxygen Reduction Reaction in Graphene/Metal Oxide Nanohybrids: Effects of Nitrogen-containing Solvent

PubMed Central

Kao, Wei-Yao; Chen, Wei-Quan; Chiu, Yu-Hsiang; Ho, Yu-Hsuan; Chen, Chun-Hu

2016-01-01

A general solvent-dependent protocol directly influencing the oxygen reduction reaction (ORR) in metal oxide/graphene nanohybrids has been demonstrated. We conducted the two-step synthesis of cobalt oxide/N-doped graphene nanohybrids (CNG) with solvents of water, ethanol, and dimethylformamide (DMF), representing tree typical categories of aqueous, polar organic, and organic N-containing solvents commonly adopted for graphene nanocomposites preparation. The superior ORR performance of the DMF-hybrids can be attributed to the high nitrogen-doping, aggregation-free hybridization, and unique graphene porous structures. As DMF is the more effective N-source, the spectroscopic results support a catalytic nitrogenation potentially mediated by cobalt-DMF coordination complexes. The wide-distribution of porosity (covering micro-, meso-, to macro-pore) and micron-void assembly of graphene may further enhance the diffusion kinetics for ORR. As the results, CNG by DMF-synthesis exhibits the high ORR activities close to Pt/C (i.e. only 8 mV difference of half-wave potential with electron transfer number of 3.96) with the better durability in the alkaline condition. Additional graphene hybrids comprised of iron and manganese oxides also show the superior ORR activities by DMF-synthesis, confirming the general solvent-dependent protocol to achieve enhanced ORR activities. PMID:27853187

Graphene Oxide/Silver Nanohybrid as Multi-functional Material for Highly Efficient Bacterial Disinfection and Detection of Organic Dye

NASA Astrophysics Data System (ADS)

Tam, Le Thi; Dinh, Ngo Xuan; Van Cuong, Nguyen; Van Quy, Nguyen; Huy, Tran Quang; Ngo, Duc-The; Mølhave, Kristian; Le, Anh-Tuan

2016-10-01

In this work, a multi-functional hybrid system consisting of graphene oxide and silver nanoparticles (GO-Ag NPs) was successfully synthesized by using a two-step chemical process. We firstly demonstrated noticeable bactericidal ability of the GO-Ag hybrid system. We provide more chemo-physical evidence explaining the antibacterial behavior of GO-Ag nanohybrid against Gram-negative Escherichia Coli and Gram-positive Staphylococcus aureus in light of ultrastructural damage analyses and Ag1+ ions release rate onto the cells/medium. A further understanding of the mode of antimicrobial action is very important for designing and developing advanced antimicrobial systems. Secondly, we have also demonstrated that the GO-Ag nanohybrid material could be used as a potential surface enhanced Raman scattering (SERS) substrate to detect and quantify organic dyes, e.g., methylene blue (MB), in aqueous media. Our findings revealed that the GO-Ag hybrid system showed better SERS performance of MB detection than that of pure Ag-NPs. MB could be detected at a concentration as low as 1 ppm. The GO-Ag-based SERS platform can be effectively used to detect trace concentrations of various types of organic dyes in aqueous media. With the aforementioned properties, the GO-Ag hybrid system is found to be very promising as a multi-functional material for advanced biomedicine and environmental monitoring applications.

Cholesteryl butyrate solid lipid nanoparticles inhibit the adhesion and migration of colon cancer cells

PubMed Central

Minelli, R; Serpe, L; Pettazzoni, P; Minero, V; Barrera, G; Gigliotti, CL; Mesturini, R; Rosa, AC; Gasco, P; Vivenza, N; Muntoni, E; Fantozzi, R; Dianzani, U; Zara, GP; Dianzani, C

2012-01-01

BACKGROUND AND PURPOSE Cholesteryl butyrate solid lipid nanoparticles (cholbut SLN) provide a delivery system for the anti-cancer drug butyrate. These SLN inhibit the adhesion of polymorphonuclear cells to the endothelium and may act as anti-inflammatory agents. As cancer cell adhesion to endothelium is crucial for metastasis dissemination, here we have evaluated the effect of cholbut SLN on adhesion and migration of cancer cells. EXPERIMENTAL APPROACH Cholbut SLN was incubated with a number of cancer cell lines or human umbilical vein endothelial cells (HUVEC) and adhesion was quantified by a computerized micro-imaging system. Migration was detected by the scratch ‘wound-healing’ assay and the Boyden chamber invasion assay. Expression of ERK and p38 MAPK was analysed by Western blot. Expression of the mRNA for E-cadherin and claudin-1 was measured by RT-PCR. KEY RESULTS Cholbut SLN inhibited HUVEC adhesiveness to cancer cell lines derived from human colon–rectum, breast, prostate cancers and melanoma. The effect was concentration and time-dependent and exerted on both cancer cells and HUVEC. Moreover, these SLN inhibited migration of cancer cells and substantially down-modulated ERK and p38 phosphorylation. The anti-adhesive effect was additive to that induced by the triggering of B7h, which is another stimulus inhibiting both ERK and p38 phosphorylation, and cell adhesiveness. Furthermore, cholbut SLN induced E-cadherin and inhibited claudin-1 expression in HUVEC. CONCLUSION AND IMPLICATIONS These results suggest that cholbut SLN could act as an anti-metastastic agent and they add a new mechanism to the anti-tumour activity of this multifaceted preparation of butyrate. PMID:22049973

Reflectometric measurement of n-hexane adsorption on ZnO2 nanohybrid film modified by hydrophobic gold nanoparticles

NASA Astrophysics Data System (ADS)

Sebők, Dániel; Csapó, Edit; Ábrahám, Nóra; Dékány, Imre

2015-04-01

Zinc-peroxide/poly(styrenesulfonate) nanohybrid thin films (containing 20 bilayers: [ZnO2/PSS]20, d ∼ 500 nm) were prepared using layer-by-layer (LbL) method. The thin film surface was functionalized by different surface modifying agents (silanes, alkylthiols and hydrophobized nanoparticles). Based on the experimental results of quartz crystal microbalance (QCM) and contact angle measurements (as prequalifications) the octanethiol covered gold nanoparticles (OT-AuNPs) were selected for further vapour adsorption studies. Reflectometric interference spectroscopy (RIfS) was used to measure n-hexane vapour adsorption on the original and modified nanohybrid films in a gas flow platform. The thin film provides only the principle of the measurement (by interference phenomenon), the selectivity and hydrophobicity is controlled and enhanced by surface functionalization (by dispersion interaction between the alkyl chains). The interference pattern shift (Δλ) caused by the increase of the optical thickness of the thin film due to vapour adsorption was investigated. It was found that due to the surface functionalization by hydrophobic nanoparticles the effect of water vapour adsorption decreased significantly, while for n-hexane opposite tendency was observed (the effective refractive index and thus the interference pattern shift increased drastically). The correlation between QCM technique and optical method (RIfS) was specified: linear specific adsorbed amount vs. wavelength shift calibration curves were determined in the pr = 0-0.4 relative vapour pressure range. The thin film is suitable for sensorial application (e.g. volatile organic compound/VOC sensor).

High-Performance Capacitive Deionization Disinfection of Water with Graphene Oxide-graft-Quaternized Chitosan Nanohybrid Electrode Coating.

PubMed

Wang, Yilei; El-Deen, Ahmed G; Li, Peng; Oh, Bernice H L; Guo, Zanru; Khin, Mya Mya; Vikhe, Yogesh S; Wang, Jing; Hu, Rebecca G; Boom, Remko M; Kline, Kimberly A; Becker, David L; Duan, Hongwei; Chan-Park, Mary B

2015-10-27

Water disinfection materials should ideally be broad-spectrum-active, nonleachable, and noncontaminating to the liquid needing sterilization. Herein, we demonstrate a high-performance capacitive deionization disinfection (CDID) electrode made by coating an activated carbon (AC) electrode with cationic nanohybrids of graphene oxide-graft-quaternized chitosan (GO-QC). Our GO-QC/AC CDID electrode can achieve at least 99.9999% killing (i.e., 6 log reduction) of Escherichia coli in water flowing continuously through the CDID cell. Without the GO-QC coating, the AC electrode alone cannot kill the bacteria and adsorbs a much smaller fraction (<82.8 ± 1.8%) of E. coli from the same biocontaminated water. Our CDID process consists of alternating cycles of water disinfection followed by electrode regeneration, each a few minutes duration, so that this water disinfection process can be continuous and it only needs a small electrode voltage (2 V). With a typical brackish water biocontamination (with 10(4) CFU mL(-1) bacteria), the GO-QC/AC electrodes can kill 99.99% of the E. coli in water for 5 h. The disinfecting GO-QC is securely attached on the AC electrode surface, so that it is noncontaminating to water, unlike many other chemicals used today. The GO-QC nanohybrids have excellent intrinsic antimicrobial properties in suspension form. Further, the GO component contributes toward the needed surface conductivity of the CDID electrode. This CDID process offers an economical method toward ultrafast, contaminant-free, and continuous killing of bacteria in biocontaminated water. The proposed strategy introduces a green in situ disinfectant approach for water purification.

In Situ Electrochemical Sensing and Real-Time Monitoring Live Cells Based on Freestanding Nanohybrid Paper Electrode Assembled from 3D Functionalized Graphene Framework.

PubMed

Zhang, Yan; Xiao, Jian; Lv, Qiying; Wang, Lu; Dong, Xulin; Asif, Muhammad; Ren, Jinghua; He, Wenshan; Sun, Yimin; Xiao, Fei; Wang, Shuai

2017-11-08

In this work, we develop a new type of freestanding nanohybrid paper electrode assembled from 3D ionic liquid (IL) functionalized graphene framework (GF) decorated by gold nanoflowers (AuNFs), and explore its practical application in in situ electrochemical sensing of live breast cell samples by real-time tracking biomarker H 2 O 2 released from cells. The AuNFs modified IL functionalized GF (AuNFs/IL-GF) was synthesized via a facile and efficient dopamine-assisted one-pot self-assembly strategy. The as-obtained nanohybrid assembly exhibits a typical 3D hierarchical porous structure, where the highly active electrocatalyst AuNFs are well dispersed on IL-GF scaffold. And the graft of hydrophilic IL molecules (i.e., 1-butyl-3-methylimidazolium tetrafluoroborate, BMIMBF 4 ) on graphene nanosheets not only avoids their agglomeration and disorder stacking during the self-assembly but also endows the integrated IL-GF monolithic material with unique hydrophilic properties, which enables it to be readily dispersed in aqueous solution and processed into freestanding paperlike material. Because of the unique structural properties and the combinational advantages of different components in the AuNFs/IL-GF composite, the resultant nanohybrid paper electrode exhibits good nonenzymatic electrochemical sensing performance toward H 2 O 2 . When used in real-time tracking H 2 O 2 secreted from different breast cells attached to the paper electrode without or with radiotherapy treatment, the proposed electrochemical sensor based on freestanding AuNFs/IL-GF paper electrode can distinguish the normal breast cell HBL-100 from the cancer breast cells MDA-MB-231 and MCF-7 cells, and assess the radiotherapy effects to different breast cancer cells, which opens a new horizon in real-time monitoring cancer cells by electrochemical sensing platform.

Synthesis and application of nanohybrids based on upconverting nanoparticles and polymers.

PubMed

Cheng, Ziyong; Lin, Jun

2015-05-01

Lanthanide-doped upconversion nanoparticles (UCNPs) have been an emerging and exciting research field in recent years due to their unique luminescent properties of converting near-infrared light to shorter wavelength radiation. UCNPs offer excellent prospects in luminescent labeling, displays, bioimaging, bioassays, drug delivery, sensors, and anticounterfeiting applications. Along with the abundant studies and rapid progress in this area, UCNPs are promising to be a new class of luminescent probe owing to their special advantages over the conventional organic dyes and quantum dots. Among them, polymers play an important role to improve properties or endow new function of UCNPs such as for matrix materials, water solubility, linking active targeting molecules, biocompatibility, and stimuli-responsive behavior. This article briefly reviews the compositions, optical mechanisms, architectures of upconversion nanocrystals and highlights the works on various functional UCNPs/polymer nanohybrids as well as many new interesting fruits in applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hierarchical Cobalt Hydroxide and B/N Co-Doped Graphene Nanohybrids Derived from Metal-Organic Frameworks for High Energy Density Asymmetric Supercapacitors

PubMed Central

Tabassum, Hassina; Mahmood, Asif; Wang, Qingfei; Xia, Wei; Liang, Zibin; Qiu, Bin; zhao, Ruo; Zou, Ruqiang

2017-01-01

To cater for the demands of electrochemical energy storage system, the development of cost effective, durable and highly efficient electrode materials is desired. Here, a novel electrode material based on redox active β-Co(OH)2 and B, N co-doped graphene nanohybrid is presented for electrochemical supercapacitor by employing a facile metal-organic frameworks (MOFs) route through pyrolysis and hydrothermal treatment. The Co(OH)2 could be firmly stabilized by dual protection of N-doped carbon polyhedron (CP) and B/N co-doped graphene (BCN) nanosheets. Interestingly, the porous carbon and BCN nanosheets greatly improve the charge storage, wettability, and redox activity of electrodes. Thus the hybrid delivers specific capacitance of 1263 F g−1 at a current density of 1A g−1 with 90% capacitance retention over 5000 cycles. Furthermore, the new aqueous asymmetric supercapacitor (ASC) was also designed by using Co(OH)2@CP@BCN nanohybrid and BCN nanosheets as positive and negative electrodes respectively, which leads to high energy density of 20.25 Whkg−1. This device also exhibits excellent rate capability with energy density of 15.55 Whkg−1 at power density of 9331 Wkg−1 coupled long termed stability up to 6000 cycles. PMID:28240224

Hierarchical Cobalt Hydroxide and B/N Co-Doped Graphene Nanohybrids Derived from Metal-Organic Frameworks for High Energy Density Asymmetric Supercapacitors.

PubMed

Tabassum, Hassina; Mahmood, Asif; Wang, Qingfei; Xia, Wei; Liang, Zibin; Qiu, Bin; Zhao, Ruo; Zou, Ruqiang

2017-02-27

To cater for the demands of electrochemical energy storage system, the development of cost effective, durable and highly efficient electrode materials is desired. Here, a novel electrode material based on redox active β-Co(OH) 2 and B, N co-doped graphene nanohybrid is presented for electrochemical supercapacitor by employing a facile metal-organic frameworks (MOFs) route through pyrolysis and hydrothermal treatment. The Co(OH) 2 could be firmly stabilized by dual protection of N-doped carbon polyhedron (CP) and B/N co-doped graphene (BCN) nanosheets. Interestingly, the porous carbon and BCN nanosheets greatly improve the charge storage, wettability, and redox activity of electrodes. Thus the hybrid delivers specific capacitance of 1263 F g -1 at a current density of 1A g -1 with 90% capacitance retention over 5000 cycles. Furthermore, the new aqueous asymmetric supercapacitor (ASC) was also designed by using Co(OH) 2 @CP@BCN nanohybrid and BCN nanosheets as positive and negative electrodes respectively, which leads to high energy density of 20.25 Whkg -1 . This device also exhibits excellent rate capability with energy density of 15.55 Whkg -1 at power density of 9331 Wkg -1 coupled long termed stability up to 6000 cycles.

Inhibited solid propellant composition containing beryllium hydride

NASA Technical Reports Server (NTRS)

Thompson, W. W. (Inventor)

1978-01-01

An object of this invention is to provide a composition of beryllium hydride and carboxy-terminated polybutadiene which is stable. Another object of this invention is to provide a method for inhibiting the reactivity of beryllium hydride toward carboxy-terminated polybutadiene. It was found that a small amount of lecithin inhibits the reaction of beryllium hydride with the acid groups in carboxy terminated polybutadiene.

Physiochemical properties of experimental nano-hybrid MTA

PubMed Central

Akhavan Zanjani, V; Tabari, K; Sheikh-Al-Eslamian, SM; Abrandabadi, AN

2017-01-01

Introduction: Development of new pulp capping agents has paved the way towards the preservation of pulp vitality, which is an important goal in restorative dentistry. This study sought to assess the calcium ion release, pH and setting of mineral trioxide aggregate (MTA) Angelus, an experimental formulation of nano-hybrid MTA containing nano-SiO2, nano-Al2O3 and nano-TiO2 and MTA Angelus plus nano-oxides. Methods: In this experimental study, five specimens from each material were placed in polypropylene tubes and immersed in a flask containing deionized distilled water. The quantity of calcium ions released into the solution from each material was measured at 15 minutes, one hour, and 24 hours by using atomic absorption spectroscopy. The pH of the solutions was measured by using a pH meter at the respective time points. The setting time was also assessed by using a Gilmore needle. Data were analyzed by using repeated measure ANOVA. Results: The quantity of released calcium ions was not significantly different among the groups (P=0.060). All materials were alkaline and the pH at 24 hours was significantly higher than the other two time points in all groups (P<0.001). The experimental group had the shortest and the MTA Angelus had the longest setting time. All materials were alkaline and capable of releasing calcium. Addition of nanoparticles to MTA Angelus significantly decreased the setting time but had no effect on the release of calcium ions or pH. Abbreviations: MTA = mineral trioxide aggregate, VPT = vital pulp therapy PMID:29075348

Correction: One-step coelectrodeposition-assisted layer-by-layer assembly of gold nanoparticles and reduced graphene oxide and its self-healing three-dimensional nanohybrid for an ultrasensitive DNA sensor.

PubMed

Jayakumar, Kumarasamy; Camarada, María Belén; Dharuman, Venkataraman; Ju, Huangxian; Dey, Ramendra Sundar; Wen, Yangping

2018-02-01

Correction for 'One-step coelectrodeposition-assisted layer-by-layer assembly of gold nanoparticles and reduced graphene oxide and its self-healing three-dimensional nanohybrid for an ultrasensitive DNA sensor' by Jayakumar Kumarasamy, et al., Nanoscale, 2018, DOI: 10.1039/c7nr06952a.

Effect of protective coating on marginal integrity of nanohybrid composite during bleaching with carbamide peroxide: A microleakage study.

PubMed

Kumar, A Ashok; Hariharavel, V P; Narayanan, Ashwin; Murali, S

2015-01-01

The aim of the study was to evaluate the microleakage on the marginal integrity of nanohybrid composite during bleaching with carbamide peroxide after applying a protective coating of G-Coat plus (GC, Japan). Class V cavities were prepared and restored with nanohybrid composite restoration in 60 freshly extracted noncarious premolars extracted for orthodontic reasons. Then they were divided into 3 groups. Group 1 - bleaching with carbamide peroxide without G coat plus (n = 20), Group 2 - bleaching with carbamide peroxide with G-Coat plus (n = 20), Group 3 - without bleaching procedure (n = 20) (control group). In Group 2, G coat plus was applied over the restorative surface and margins. Then all teeth in Groups 1 and 2 were taken and mounted in dental stone. Bleaching trays were custom fabricated over the cast with the help of a heated vacuum-forming machine. 10% carbamide peroxide (opalescence PF) was applied over the tooth, and the bleaching process was done for about 2 weeks. Then all samples underwent thermocycling and were then immersed in the 2% methylene blue solution for 24 h and observed under a stereomicroscope to evaluate the amount of dye penetration. Data were compared using Kruskal-Wallis test and Mann-Whitney test using SPSS Inc.; Chicago, IL, USA, Version 17.0. Mann-Whitney test shows that the difference in microleakage between Group 1-Group 2 and Group 2-Group 3 is statistically significant (P < 0.05). Significant reduction in microleakage was seen in Group 2 when compared to other groups.

Preparation of zinc hydroxystannate-decorated graphene oxide nanohybrids and their synergistic reinforcement on reducing fire hazards of flexible poly (vinyl chloride)

NASA Astrophysics Data System (ADS)

Gao, Tingting; Chen, Laicheng; Li, Zhiwei; Yu, Laigui; Wu, Zhishen; Zhang, Zhijun

2016-04-01

A novel flame retardant, zinc hydroxystannate-decorated graphene oxide (ZHS/GO) nanohybrid, was successfully prepared and well characterized. Herein, the ZHS nanoparticles could not only enhance the flame retardancy of GO with the synergistic flame-retardant effect of ZHS but also prevent the restack of GO to improve the mechanical properties of poly (vinyl chloride) (PVC) matrix. The structure characterization showed ZHS nanoparticles were bonded onto the surface of GO nanosheets and the ZHS nanoparticles were well distributed on the surface of GO. Subsequently, resulting ZHS/GO was introduced into flexible PVC and fire hazards and mechanical properties of PVC nanocomposites were investigated. Compared to neat PVC, thermogravimetric analysis exhibited that the addition of ZHS/GO into PVC matrix led to an improvement of the charring amount and thermal stability of char residue. Moreover, the incorporation of 5 wt.% ZHS/GO imparted excellent flame retardancy to flexible PVC, as shown by increased limiting oxygen index, reduced peak heat release rate, and total heat release tested by an oxygen index meter and a cone calorimeter, respectively. In addition, the addition of ZHS/GO nanohybrids decreased the smoke products and increased the tensile strength of PVC. Above-excellent flame-retardant properties are generally attributed to the synergistic effect of GO and ZHS, containing good dispersion of ZHS/GO in PVC matrix, the physical barrier of GO, and the catalytic char function of ZHS.

Nanoparticle-Mediated Physical Exfoliation of Aqueous-Phase Graphene for Fabrication of Three-Dimensionally Structured Hybrid Electrodes.

PubMed

Lee, Younghee; Choi, Hojin; Kim, Min-Sik; Noh, Seonmyeong; Ahn, Ki-Jin; Im, Kyungun; Kwon, Oh Seok; Yoon, Hyeonseok

2016-01-27

Monodispersed polypyrrole (PPy) nanospheres were physically incorporated as guest species into stacked graphene layers without significant property degradation, thereby facilitating the formation of unique three-dimensional hybrid nanoarchitecture. The electrochemical properties of the graphene/particulate PPy (GPPy) nanohybrids were dependent on the sizes and contents of the PPy nanospheres. The nanohybrids exhibited optimum electrochemical performance in terms of redox activity, charge-transfer resistance, and specific capacitance at an 8:1 PPy/graphite (graphene precursor) weight ratio. The packing density of the alternately stacked nanohybrid structure varied with the nanosphere content, indicating the potential for high volumetric capacitance. The nanohybrids also exhibited good long-term cycling stability because of a structural synergy effect. Finally, fabricated nanohybrid-based flexible all-solid state capacitor cells exhibited good electrochemical performance in an acidic electrolyte with a maximum energy density of 8.4 Wh kg(-1) or 1.9 Wh L(-1) at a maximum power density of 3.2 kW kg(-1) or 0.7 kW L(-1); these performances were based on the mass or packing density of the electrode materials.

Nanoparticle-Mediated Physical Exfoliation of Aqueous-Phase Graphene for Fabrication of Three-Dimensionally Structured Hybrid Electrodes

PubMed Central

Lee, Younghee; Choi, Hojin; Kim, Min-Sik; Noh, Seonmyeong; Ahn, Ki-Jin; Im, Kyungun; Kwon, Oh Seok; Yoon, Hyeonseok

2016-01-01

Monodispersed polypyrrole (PPy) nanospheres were physically incorporated as guest species into stacked graphene layers without significant property degradation, thereby facilitating the formation of unique three-dimensional hybrid nanoarchitecture. The electrochemical properties of the graphene/particulate PPy (GPPy) nanohybrids were dependent on the sizes and contents of the PPy nanospheres. The nanohybrids exhibited optimum electrochemical performance in terms of redox activity, charge-transfer resistance, and specific capacitance at an 8:1 PPy/graphite (graphene precursor) weight ratio. The packing density of the alternately stacked nanohybrid structure varied with the nanosphere content, indicating the potential for high volumetric capacitance. The nanohybrids also exhibited good long-term cycling stability because of a structural synergy effect. Finally, fabricated nanohybrid-based flexible all–solid state capacitor cells exhibited good electrochemical performance in an acidic electrolyte with a maximum energy density of 8.4 Wh kg−1 or 1.9 Wh L−1 at a maximum power density of 3.2 kW kg−1 or 0.7 kW L−1; these performances were based on the mass or packing density of the electrode materials. PMID:26813878

Herbicide-Intercalated Zinc Layered Hydroxide Nanohybrid for a Dual-Guest Controlled Release Formulation

PubMed Central

Hussein, Mohd Zobir; Rahman, Nor Shazlirah Shazlyn Abdul; Sarijo, Siti H.; Zainal, Zulkarnain

2012-01-01

Herbicides, namely 4-(2,4-dichlorophenoxy) butyrate (DPBA) and 2-(3-chlorophenoxy) propionate (CPPA), were intercalated simultaneously into the interlayers of zinc layered hydroxide (ZLH) by direct reaction of zinc oxide with both anions under aqueous environment to form a new nanohybrid containing both herbicides labeled as ZCDX. Successful intercalation of both anions simultaneously into the interlayer gallery space of ZLH was studied by PXRD, with basal spacing of 28.7 Å and supported by FTIR, TGA/DTG and UV-visible studies. Simultaneous release of both CPPA and DPBA anions into the release media was found to be governed by a pseudo second-order equation. The loading and percentage release of the DPBA is higher than the CPPA anion, which indicates that the DPBA anion was preferentially intercalated into and released from the ZLH interlayer galleries. This work shows that layered single metal hydroxide, particularly ZLH, is a suitable host for the controlled release formulation of two herbicides simultaneously. PMID:22837696

‘Spotted Nanoflowers’: Gold-seeded Zinc Oxide Nanohybrid for Selective Bio-capture

NASA Astrophysics Data System (ADS)

Perumal, Veeradasan; Hashim, U.; Gopinath, Subash C. B.; Haarindraprasad, R.; Foo, K. L.; Balakrishnan, S. R.; Poopalan, P.

2015-07-01

Hybrid gold nanostructures seeded into nanotextured zinc oxide (ZnO) nanoflowers (NFs) were created for novel biosensing applications. The selected ‘spotted NFs’ had a 30-nm-thick gold nanoparticle (AuNP) layer, chosen from a range of AuNP thicknesses, sputtered onto the surface. The generated nanohybrids, characterized by morphological, physical and structural analyses, were uniformly AuNP-seeded onto the ZnO NFs with an average length of 2-3 μm. Selective capture of molecular probes onto the seeded AuNPs was evidence for the specific interaction with DNA from pathogenic Leptospirosis-causing strains via hybridization and mis-match analyses. The attained detection limit was 100 fM as determined via impedance spectroscopy. High levels of stability, reproducibility and regeneration of the sensor were obtained. Selective DNA immobilization and hybridization were confirmed by nitrogen and phosphorus peaks in an X-ray photoelectron spectroscopy analysis. The created nanostructure hybrids illuminate the mechanism of generating multiple-target, high-performance detection on a single NF platform, which opens a new avenue for array-based medical diagnostics.

Adsorption of Arsenic on Multiwall Carbon Nanotube–Zirconia Nanohybrid for Potential Drinking Water Purification

PubMed Central

AddoNtim, Susana; Mitra, Somenath

2012-01-01

The adsorptive removal of arsenic from water using a multiwall carbon nanotube-zirconia nanohybrid (MWCNT-ZrO2) is presented. The MWCNT-ZrO2 with 4.85% zirconia was effective in meeting the drinking water standard levels of 10 μg L−1. The absorption capacity of the composite were 2000 μg g−1 and 5000 μg g−1 for As (III) and As (V) respectively, which were significantly higher than those reported previously for iron oxide coated MWCNTs. The adsorption of As (V) on MWCNT-ZrO2 was faster than that of As (III), and a pseudo-second order rate equation effectively described the uptake kinetics. The adsorption isotherms for As (III) and As (V) fitted both the Langmuir and Freundlich models. A major advantage of the MWCNT-ZrO2 was that the adsorption capacity was not a function of pH. PMID:22424815

In-situ laser-induced synthesis of associated YVO4:Eu3+@SiO2@Au-Ag/C nanohybrids with enhanced luminescence

NASA Astrophysics Data System (ADS)

Kolesnikov, I. E.; lvanova, T. Yu.; Ivanov, D. A.; Kireev, A. A.; Mamonova, D. V.; Golyeva, E. V.; Mikhailov, M. D.; Manshina, A. A.

2018-02-01

Associated luminescence/plasmonic nanoparticles were prepared in a single step process as a result of laser illumination (low intensity CW He-Cd laser) of colloidal solution of YVO4:Eu3+@SiO2 mixed with heterometallic supramolecular complex. The results of SEM-EDX analysis, absorption, steady-state luminescence and luminescence decay measurements revealed formation of associated nanohybrids with core/shell morphology. The obtained nanostructures demonstrated metal enhanced luminescence with enhancement factor of 1.6. The theoretical calculations revealed strong correlation of enhancement factor and plasmonic nanoparticles number.

Inhibition of cellulases by phenols

USDA-ARS?s Scientific Manuscript database

The inhibition of enzymes by the end products that they make is a well-known phenomenon. Another form of inhibition is manifested by the decrease in hydrolysis of pretreated cellulosic material as the concentration of solid biomass material increases, even though the ratio of enzyme to cellulose is...

The Effect of Single, Binary and Ternary Anions of Chloride, Carbonate and Phosphate on the Release of 2,4-Dichlorophenoxyacetate Intercalated into the Zn-Al-layered Double Hydroxide Nanohybrid

NASA Astrophysics Data System (ADS)

Hussein, Mohd Zobir; Jaafar, Adila Mohamad; Yahaya, Asmah Hj.; Zainal, Zulkarnain

2009-11-01

Intercalation of beneficial anion into inorganic host has lead to an opportunity to synthesize various combinations of new organic-inorganic nanohybrids with various potential applications; especially, for the controlled release formulation and storage purposes. Investigation on the release behavior of 2,4-dichlorophenoxyacetate (2,4-D) intercalated into the interlayer of Zn-Al-layered double hydroxide (ZAN) have been carried out using single, binary and ternary aqueous systems of chloride, carbonate and phosphate. The release behavior of the active agent 2,4-D from its double-layered hydroxide nanohybrid ZANDI was found to be of controlled manner governed by pseudo-second order kinetics. It was found that carbonate medium yielded the highest accumulated release of 2,4-D, while phosphate in combination with carbonate and/or nitrate speeds up the release rate of 2,4-D. These results indicate that it is possible to design and develop new delivery system of latex stimulant compound with controlled release property based on 2,4-D that is known as a substance to increase latex production of rubber tree, Hevea brasiliensis.

Metal organic chemical vapor deposition of environmental barrier coatings for the inhibition of solid deposit formation from heated jet fuel

NASA Astrophysics Data System (ADS)

Mohan, Arun Ram

Solid deposit formation from jet fuel compromises the fuel handling system of an aviation turbine engine and increases the maintenance downtime of an aircraft. The deposit formation process depends upon the composition of the fuel, the nature of metal surfaces that come in contact with the heated fuel and the operating conditions of the engine. The objective of the study is to investigate the effect of substrate surfaces on the amount and nature of solid deposits in the intermediate regime where both autoxidation and pyrolysis play an important role in deposit formation. A particular focus has been directed to examining the effectiveness of barrier coatings produced by metal organic chemical vapor deposition (MOCVD) on metal surfaces for inhibiting the solid deposit formation from jet fuel degradation. In the first part of the experimental study, a commercial Jet-A sample was stressed in a flow reactor on seven different metal surfaces: AISI316, AISI 321, AISI 304, AISI 347, Inconel 600, Inconel 718, Inconel 750X and FecrAlloy. Examination of deposits by thermal and microscopic analysis shows that the solid deposit formation is influenced by the interaction of organosulfur compounds and autoxidation products with the metal surfaces. The nature of metal sulfides was predicted by Fe-Ni-S ternary phase diagram. Thermal stressing on uncoated surfaces produced coke deposits with varying degree of structural order. They are hydrogen-rich and structurally disordered deposits, spherulitic deposits, small carbon particles with relatively ordered structures and large platelets of ordered carbon structures formed by metal catalysis. In the second part of the study, environmental barrier coatings were deposited on tube surfaces to inhibit solid deposit formation from the heated fuel. A new CVD system was configured by the proper choice of components for mass flow, pressure and temperature control in the reactor. A bubbler was designed to deliver the precursor into the reactor

Adsorption of arsenic on multiwall carbon nanotube-zirconia nanohybrid for potential drinking water purification.

PubMed

Ntim, Susana Addo; Mitra, Somenath

2012-06-01

The adsorptive removal of arsenic from water using a multiwall carbon nanotube-zirconia nanohybrid (MWCNT-ZrO(2)) is presented. The MWCNT-ZrO(2) with 4.85% zirconia was effective in meeting the drinking water standard levels of 10 μg L(-1). The absorption capacity of the composite were 2000 μg g(-1) and 5000 μg g(-1) for As(III) and As(V) respectively, which were significantly higher than those reported previously for iron oxide coated MWCNTs. The adsorption of As(V) on MWCNT-ZrO(2) was faster than that of As(III), and a pseudo-second order rate equation effectively described the uptake kinetics. The adsorption isotherms for As(III) and As(V) fitted both the Langmuir and Freundlich models. A major advantage of the MWCNT-ZrO(2) was that the adsorption capacity was not a function of pH. Copyright © 2012 Elsevier Inc. All rights reserved.

Synthesis of free-standing carbon nanohybrid by directly growing carbon nanotubes on air-sprayed graphene oxide paper and its application in supercapacitor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wei, Li; Jiang, Wenchao; Yuan, Yang

We report the synthesis of a free-standing two dimensional carbon nanotube (CNT)-reduced graphene oxide (rGO) hybrid by directly growing CNTs on air-sprayed GO paper. As a result of the good integration between CNTs and thermally reduced GO film during chemical vapor deposition, excellent electrical conductivity (2.6×10{sup 4} S/m), mechanical flexibility (electrical resistance only increases 1.1% after bent to 90° for 500 times) and a relatively large surface area (335.3 m{sup 2}/g) are achieved. Two-electrode supercapacitor assembled using the CNT–rGO hybrids in ionic liquid electrolyte (1-ethyl-3-methylimidazolium tetrafluoroborate) shows excellent stability upon 500 bending cycles with the gravimetric energy density measuring 23.7more » Wh/kg and a power density of 2.0 kW/kg. Furthermore, it shows an impedance phase angle of −64.4° at a frequency of 120 Hz, suggesting good potentials for 120 Hz alternating current line filtering applications. - Graphical abstract: Flexible and highly conductive carbon nanotube-reduced graphene oxide nanohybrid. - Highlights: • Direct growth of carbon nanotubes by chemical vapor deposition on air-sprayed graphene oxide paper. • Two-dimensional carbon nanohybrid with excellent conductivity and mechanical flexibility. • Supercapacitor with excellent performance stability upon mechanical deformation for flexible electronics applications. • Supercapacitor with high impedance phase angle for 120 Hz alternating current line filtering applications.« less

Cholesteryl butyrate solid lipid nanoparticles inhibit adhesion of human neutrophils to endothelial cells

PubMed Central

Dianzani, Chiara; Cavalli, Roberta; Zara, Gian Paolo; Gallicchio, Margherita; Lombardi, Grazia; Gasco, Maria Rosa; Panzanelli, Patrizia; Fantozzi, Roberto

2006-01-01

Adhesion of polymorphonuclear cells (PMNs) to vascular endothelial cells (EC) is a critical step in recruitment and infiltration of leukocytes into tissues during inflammation. High doses of butyric acid have been shown to ameliorate inflammation in inflammatory bowel diseases (IBD). Cholesteryl-butyrate solid lipid nanoparticles (chol-but SLN) as prodrug are a possible delivery system for butyric acid. Sodium butyrate or chol-but SLN were coincubated with human PMNs and human umbilical vein EC (HUVEC); adhesion was quantified by computerized microimaging fluorescence analysis. Both chol-but SLN and sodium butyrate displayed antiadhesive effects on FMLP- and IL-1β-stimulated cells in a concentration–response curve (10−8–10−5 M), but chol-but SLN were in all cases more active. Moreover, chol-but SLN inhibited FMLP-induced adhesion of PMNs to FCS-coated plastic wells, thus showing a direct effect on PMNs, while sodium butyrate had little effect. Confocal microscopy showed that fluorescent SLN entered PMNs and HUVEC after 10 min incubation. Chol-but SLN acted either on activated PMN or HUVEC. Chol-but SLN inhibited O2−· production and myeloperoxidase release by PMNs evoked by FMLP, in a dose-dependent, but not time-dependent, manner and were more active than sodium butyrate. In conclusion, in all tests chol-but SLN were more active than sodium butyrate. Thus, chol-but SLN might be a valid alternative to sodium butyrate in the anti-inflammatory therapy of ulcerative colitis, avoiding complications related to the administration of sodium butyrate. PMID:16702992

Indigenous microbial capability in solid manure residues to start-up solid-phase anaerobic digesters.

PubMed

Yap, S D; Astals, S; Jensen, P D; Batstone, D J; Tait, S

2017-06-01

Batch solid-phase anaerobic digestion is a technology for sustainable on-farm treatment of solid residues, but is an emerging technology that is yet to be optimised with respect to start-up and inoculation. In the present study, spent bedding from two piggeries (site A and B) were batch digested at total solids (TS) concentration of 5, 10 and 20% at mesophilic (37°C) and thermophilic (55°C) temperatures, without adding an external inoculum. The results showed that the indigenous microbial community present in spent bedding was able to recover the full methane potential of the bedding (140±5 and 227±6L CH 4 kgVS fed -1 for site A and B, respectively), but longer treatment times were required than for digestion with an added external inoculum. Nonetheless, at high solid loadings (i.e. TS level>10%), the digestion performance was affected by chemical inhibition due to ammonia and/or humic acid. Thermophilic temperatures did not influence digestion performance but did increase start-up failure risk. Further, inoculation of residues from the batch digestion to subsequent batch enhanced start-up and achieved full methane potential recovery of the bedding. Inoculation with liquid residue (leachate) was preferred over a solid residue, to preserve treatment capacity for fresh substrate. Overall, the study highlighted that indigenous microbial community in the solid manure residue was capable of recovering full methane potential and that solid-phase digestion was ultimately limited by chemical inhibition rather than lack of suitable microbial community. Copyright © 2017 Elsevier Ltd. All rights reserved.

Biogas production from undiluted chicken manure and maize silage: A study of ammonia inhibition in high solids anaerobic digestion.

PubMed

Sun, Chen; Cao, Weixing; Banks, Charles J; Heaven, Sonia; Liu, Ronghou

2016-10-01

The feasibility of co-digestion of chicken manure (CM) and maize silage (MS) without water dilution was investigated in 5-L digesters. Specific methane production (SMP) of 0.309LCH4g(-1) volatile solids (VS) was achieved but only at lower %CM. Above a critical threshold for total ammonia nitrogen (TAN), estimated at 7gNL(-1), VFA accumulated with a characteristic increase in acetic acid followed by its reduction and an increase in propionic acid. During this transition the predominant methanogenic pathway was hydrogenotrophic. Methanogenesis was completely inhibited at TAN of 9gNL(-1). The low digestibility of the mixed feedstock led to a rise in digestate TS and a reduction in SMP over the 297-day experimental period. Methanogenesis appeared to be failing in one digester but was recovered by reducing the %CM. Co-digestion was feasible with CM ⩽20% of feedstock VS, and the main limiting factor was ammonia inhibition. Copyright © 2016 Elsevier Ltd. All rights reserved.

Gold Nanoparticle-Quantum Dot Fluorescent Nanohybrid: Application for Localized Surface Plasmon Resonance-induced Molecular Beacon Ultrasensitive DNA Detection

NASA Astrophysics Data System (ADS)

Adegoke, Oluwasesan; Park, Enoch Y.

2016-11-01

In biosensor design, localized surface plasmon resonance (LSPR)-induced signal from gold nanoparticle (AuNP)-conjugated reporter can produce highly sensitive nanohybrid systems. In order to retain the physicochemical properties of AuNPs upon conjugation, high colloidal stability in aqueous solution is needed. In this work, the colloidal stability with respect to the zeta potential (ZP) of four negatively charged thiol-functionalized AuNPs, thioglycolic (TGA)-AuNPs, 3-mercaptopropionic acid (MPA)-AuNPs, l-cysteine-AuNPs and l-glutathione (GSH)-AuNPs, and a cationic cyteamine-capped AuNPs was studied at various pHs, ionic strength, and NP concentration. A strong dependence of the ZP charge on the nanoparticle (NP) concentration was observed. High colloidal stability was exhibited between pH 3 and 9 for the negatively charged AuNPs and between pH 3 and 7 for the cationic AuNPs. With respect to the ionic strength, high colloidal stability was exhibited at ≤104 μM for TGA-AuNPs, l-cysteine-AuNPs, and GSH-AuNPs, whereas ≤103 μM is recommended for MPA-AuNPs. For the cationic AuNPs, very low ionic strength of ≤10 μM is recommended due to deprotonation at higher concentration. GSH-AuNPs were thereafter bonded to SiO2-functionalized alloyed CdZnSeS/ZnSe1.0S1.3 quantum dots (SiO2-Qdots) to form a plasmon-enhanced AuNP-SiO2-Qdots fluorescent nanohybrid. The AuNP-SiO2-Qdots conjugate was afterward conjugated to a molecular beacon (MB), thus forming an ultrasensitive LSPR-induced SiO2-Qdots-MB biosensor probe that detected a perfect nucleotide DNA sequence at a concentration as low as 10 fg/mL. The limit of detection was 11 fg/mL (1.4 fM) while the biosensor probe efficiently distinguished between single-base mismatch and noncomplementary sequence target.

An electrochemical dopamine sensor based on the ZnO/CuO nanohybrid structures.

PubMed

Khun, K; Ibupoto, Z H; Liu, X; Mansor, N A; Turner, A P F; Beni, V; Willander, M

2014-09-01

The selective detection of dopamine (DA) is of great importance in the modern medicine because dopamine is one of the main regulators in human behaviour. In this study, ZnO/CuO nanohybrid structures, grown on the gold coated glass substrate, have been investigated as a novel electrode material for the electrochemical detection of dopamine. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) techniques were used for the material characterization and the obtained results are in good agreement. The selective determination of dopamine was demonstrated by cyclic voltammetry (CV) and amperometric experiments. The amperometric response was linear for dopamine concentrations between 1.0 x 10(-3) and 8.0 mM with a sensitivity of 90.9 μA mM(-1) cm(-2). The proposed dopamine biosensor is very stable, selective over common interferents as glucose, uric acid and ascorbic acid, and also good reproducibility was observed for seven electrodes. Moreover, the dopamine sensor exhibited a fast response time of less than 10 s. The wide range and acceptable sensitivity of the presented dopamine sensor provide the possible application in analysing the dopamine from the real samples.

Combination of Aryl Diselenides/Hydrogen Peroxide and Carbon Nanotube-Rhodium Nanohybrid for Naphthols Oxidation: An Efficient Route towards Trypanocidal Quinones.

PubMed

de Carvalho, Renato L; Jardim, Guilherme A M; Santos, Augusto; Araujo, Maria H; Oliveira, Willian X C; Bombaça, Ana Cristina; Menna-Barreto, Rubem F S; Gopi, Elumalai; Gravel, Edmond; Doris, Eric; da Silva Júnior, Eufrânio Nunes

2018-06-14

We report a combination of aryl diselenides/hydrogen peroxide and carbon nanotube-rhodium nanohybrid for naphthols oxidation towards synthesis of 1,4-naphthoquinones and evaluation of their relevant trypanocidal activity. Under a combination of (PhSe)2/H2O2 in the presence of O2 in i-PrOH/Hexane, several benzenoid (A-ring) substituted quinones were prepared in moderate to high yields. We also studied the contribution of RhCNT as co-catalyst in this process and, in some cases, yields were improved. This method provides an efficient and versatile alternative for preparing A-ring modified naphthoquinonoid compounds with relevant biological profile. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Enhanced catalytic hydrogenation activity of Ni/reduced graphene oxide nanocomposite prepared by a solid-state method

NASA Astrophysics Data System (ADS)

Li, Yizhao; Cao, Yali; Jia, Dianzeng

2018-01-01

A simple solid-state method has been applied to synthesize Ni/reduced graphene oxide (Ni/rGO) nanocomposite under ambient condition. Ni nanoparticles with size of 10-30 nm supported on reduced graphene oxide (rGO) nanosheets are obtained through one-pot solid-state co-reduction among nickel chloride, graphene oxide, and sodium borohydride. The Ni/rGO nanohybrid shows enhanced catalytic activity toward the reduction of p-nitrophenol (PNP) into p-aminophenol compared with Ni nanoparticles. The results of kinetic research display that the pseudo-first-order rate constant for hydrogenation reaction of PNP with Ni/rGO nanocomposite is 7.66 × 10-3 s-1, which is higher than that of Ni nanoparticles (4.48 × 10-3 s-1). It also presents superior turnover frequency (TOF, 5.36 h-1) and lower activation energy ( E a, 29.65 kJ mol-1) in the hydrogenation of PNP with Ni/rGO nanocomposite. Furthermore, composite catalyst can be magnetically separated and reused for five cycles. The large surface area and high electron transfer property of rGO support are beneficial for good catalytic performance of Ni/rGO nanocomposite. Our study demonstrates a simple approach to fabricate metal-rGO heterogeneous nanostructures with advanced functions.

Total solids content drives high solid anaerobic digestion via mass transfer limitation.

PubMed

Abbassi-Guendouz, Amel; Brockmann, Doris; Trably, Eric; Dumas, Claire; Delgenès, Jean-Philippe; Steyer, Jean-Philippe; Escudié, Renaud

2012-05-01

The role of the total solids (TS) content on anaerobic digestion was investigated in batch reactors. A range of TS contents from 10% to 35% was evaluated, four replicates were performed. The total methane production slightly decreased with TS concentrations increasing from 10% to 25% TS. Two behaviors were observed at 30% TS: two replicates had similar performances to that at 25% TS; for the two other replicates, the methane production was inhibited as observed at 35% TS. This difference suggested that 30% TS content corresponded to a threshold of the solids content, above which methanogenesis was strongly inhibited. The Anaerobic Digestion Model No. 1 (ADM1) was used to describe the experimental data. The effects of hydrolysis step and liquid/gas mass transfer were particularly investigated. The simulations showed that mass transfer limitation could explain the low methane production at high TS, and that hydrolysis rate constants slightly decreased with increasing TS. Copyright © 2012 Elsevier Ltd. All rights reserved.

Microfluidic-Assisted Production of Size-Controlled Superparamagnetic Iron Oxide Nanoparticles-Loaded Poly(methyl methacrylate) Nanohybrids.

PubMed

Ding, Shukai; Attia, Mohamed F; Wallyn, Justine; Taddei, Chiara; Serra, Christophe A; Anton, Nicolas; Kassem, Mohamad; Schmutz, Marc; Er-Rafik, Meriem; Messaddeq, Nadia; Collard, Alexandre; Yu, Wei; Giordano, Michele; Vandamme, Thierry F

2018-02-06

In this paper, superparamagnetic iron oxide nanoparticles (SPIONs, around 6 nm) encapsulated in poly(methyl methacrylate) nanoparticles (PMMA NPs) with controlled sizes ranging from 100 to 200 nm have been successfully produced. The hybrid polymeric NPs were prepared following two different methods: (1) nanoprecipitation and (2) nanoemulsification-evaporation. These two methods were implemented in two different microprocesses based on the use of an impact jet micromixer and an elongational-flow microemulsifier. SPIONs-loaded PMMA NPs synthesized by the two methods presented completely different physicochemical properties. The polymeric NPs prepared with the micromixer-assisted nanoprecipitation method showed a heterogeneous dispersion of SPIONs inside the polymer matrix, an encapsulation efficiency close to 100 wt %, and an irregular shape. In contrast, the polymeric NPs prepared with the microfluidic-assisted nanoemulsification-evaporation method showed a homogeneous dispersion, an almost complete encapsulation, and a spherical shape. The properties of the polymeric NPs have been characterized by dynamic light scattering, thermogravimetric analysis, and transmission electron microscope. In vitro cytotoxicity assays were also performed on the nanohybrids and pure PMMA NPs.

The effect of different beverages on surface hardness of nanohybrid resin composite and giomer.

PubMed

Tanthanuch, Saijai; Kukiattrakoon, Boonlert; Siriporananon, Chantima; Ornprasert, Nawanda; Mettasitthikorn, Wathu; Likhitpreeda, Salinla; Waewsanga, Sulawan

2014-05-01

To investigate the effects of five beverages (apple cider, orange juice, Coca-Cola, coffee, and beer) on microhardness and surface characteristic changes of nanohybrid resin composite and giomer. Ninety-three specimens of each resin composite and giomer were prepared. Before immersion, baseline data of Vicker's microhardness was recorded and surface characteristics were examined using scanning electron microscopy (SEM). Five groups of discs (n = 18) were alternately immersed in 25 mL of each beverage for 5 s and in 25 mL of artificial saliva for 5 s for 10 cycles. Specimens were then stored in artificial saliva for 24 h. This process was repeated for 28 days. After immersion, specimens were evaluated and data were analyzed by two-way repeated analysis of variance (ANOVA), Tukey's honestly significant difference (HSD), and a t-test (α = 0.05). Microhardness of all groups significantly decreased after being immersed in the tested beverages (P < 0.05). SEM photomicrographs presented surface degradation of all groups. The effect of these beverages on the surface of both restorative materials also depended upon the exposure time and chemical composition of the restorative materials and beverages.

The effect of different beverages on surface hardness of nanohybrid resin composite and giomer

PubMed Central

Tanthanuch, Saijai; Kukiattrakoon, Boonlert; Siriporananon, Chantima; Ornprasert, Nawanda; Mettasitthikorn, Wathu; Likhitpreeda, Salinla; Waewsanga, Sulawan

2014-01-01

Aims: To investigate the effects of five beverages (apple cider, orange juice, Coca-Cola, coffee, and beer) on microhardness and surface characteristic changes of nanohybrid resin composite and giomer. Materials and Methods: Ninety-three specimens of each resin composite and giomer were prepared. Before immersion, baseline data of Vicker's microhardness was recorded and surface characteristics were examined using scanning electron microscopy (SEM). Five groups of discs (n = 18) were alternately immersed in 25 mL of each beverage for 5 s and in 25 mL of artificial saliva for 5 s for 10 cycles. Specimens were then stored in artificial saliva for 24 h. This process was repeated for 28 days. After immersion, specimens were evaluated and data were analyzed by two-way repeated analysis of variance (ANOVA), Tukey's honestly significant difference (HSD), and a t-test (α = 0.05). Results: Microhardness of all groups significantly decreased after being immersed in the tested beverages (P < 0.05). SEM photomicrographs presented surface degradation of all groups. Conclusions: The effect of these beverages on the surface of both restorative materials also depended upon the exposure time and chemical composition of the restorative materials and beverages. PMID:24944451

Polymer dots grafted TiO2 nanohybrids as high performance visible light photocatalysts.

PubMed

Li, Gen; Wang, Feng; Liu, Peng; Chen, Zheming; Lei, Ping; Xu, Zhongshan; Li, Zengxi; Ding, Yanfen; Zhang, Shimin; Yang, Mingshu

2018-04-01

As a new member of carbon dots (CDs), Polymer dots (PDs) prepared by hydrothermal treatment of polymers, usually consist of the carbon core and the connected partially degraded polymer chains. This type of CDs might possess aqueous solubility, non-toxicity, excellent stability against photo-bleaching and high visible light activity. In this research, PDs were prepared by a moderate hydrothermal treatment of polyvinyl alcohol, and PDs grafted TiO 2 (PDs-TiO 2 ) nanohybrids with TiOC bonds were prepared by a facile in-situ hydrothermal treatment of PDs and Ti (SO 4 ) 2 . Under visible light irradiation, the PDs-TiO 2 demonstrate excellent photocatalytic activity for methyl orange degradation, and the photocatalytic rate constant of PDs-TiO 2 is 3.6 and 9.5 times higher than that of pure TiO 2 and commercial P25, respectively. In addition, the PDs-TiO 2 exhibit good recycle stability under UV-Vis light irradiation. The interfacial TiOC bonds and the π-conjugated structures in PDs-TiO 2 can act as the pathways to quickly transfer the excited electrons between PDs and TiO 2 , therefore contribute to the excellent photocatalytic activity. Copyright © 2018 Elsevier Ltd. All rights reserved.

Manganese-enriched electrochemistry of LiFePO4/RGO nanohybrid for aqueous energy storage

NASA Astrophysics Data System (ADS)

Rossouw, Claire A.; Raju, Kumar; Zheng, Haitao; Ozoemena, Kenneth I.

2017-07-01

Manganese-doped lithium iron phosphate (LFMP) integrated with reduced graphene oxide (RGO) has been prepared via microwave-assisted synthesis and investigated as lithium-ion energy storage system in aqueous Li2SO4 electrolyte. The doping of the LFP was achieved with a low-cost commercial electrolytic manganese oxide (EMD) precursor using a microwave-assisted solvothermal technique. When compared to the undoped counterpart (LFP/RGO), obtained under similar experimental conditions, the LFMP/RGO nanohybrid showed an improved electrochemical performance. The LFMP/RGO gave a maximum areal capacitance of ca. 39.48 mF cm-2, power density of 70.3 mW cm-2 and energy density of 8 mWh cm-2 compared to the values for the pristine complex (LFP/RGO); ca. 16.85 mF cm-2, 54.4 mW cm-2 and 4.8 mWh cm-2. In addition, when the two types of electrochemical storage systems were subjected to voltage-holding (floating) experiment for 50 h, LFMP/RGO maintained 98% capacitance retention while LFP/G maintained 94% capacitance retention. The findings in this work prove that Mn-doping is capable of enhancing the electrochemical performance of the LFP material for energy storage.

One-step coelectrodeposition-assisted layer-by-layer assembly of gold nanoparticles and reduced graphene oxide and its self-healing three-dimensional nanohybrid for an ultrasensitive DNA sensor.

PubMed

Kumarasamy, Jayakumar; Camarada, María Belén; Venkatraman, Dharuman; Ju, Huangxian; Dey, Ramendra Sundar; Wen, Yangping

2018-01-18

A layer-by-layer (LBL) assembly was employed for preparing multilayer thin films with a controlled architecture and composition. In this study, we report the one-step coelectrodeposition-assisted LBL assembly of both gold nanoparticles (AuNPs) and reduced graphene oxide (rGO) on the surface of a glassy carbon electrode (GCE) for the ultrasensitive electrochemical impedance sensing of DNA hybridization. A self-healable nanohybrid thin film with a three-dimensional (3D) alternate-layered nanoarchitecture was obtained by the one-step simultaneous electro-reduction of both graphene oxide and gold chloride in a high acidic medium of H 2 SO 4 using cyclic voltammetry and was confirmed by different characterization techniques. The DNA bioelectrode was prepared by immobilizing the capture DNA onto the surface of the as-obtained self-healable AuNP/rGO/AuNP/GCE with a 3D LBL nanoarchitecture via gold-thiol interactions, which then served as an impedance sensing platform for the label-free ultrasensitive electrochemical detection of DNA hybridization over a wide range from 1.0 × 10 -9 to 1.0 × 10 -13 g ml -1 , a low limit of detection of 3.9 × 10 -14 g ml -1 (S/N = 3), ultrahigh sensitivity, and excellent selectivity. This study presents a promising electrochemical sensing platform for the label-free ultrasensitive detection of DNA hybridization with potential application in cancer diagnostics and the preparation of a self-healable nanohybrid thin film with a 3D alternate-layered nanoarchitecture via a one-step coelectrodeposition-assisted LBL assembly.

Bacterial migration along solid surfaces.

PubMed Central

Harkes, G; Dankert, J; Feijen, J

1992-01-01

An in vitro system was developed to study the migration of uropathogenic Escherichia coli strains. In this system an aqueous agar gel is placed against a solid surface, allowing the bacteria to migrate along the gel/solid surface interface. Bacterial strains as well as solid surfaces were characterized by means of water contact angle and zeta potential measurements. When glass was used as the solid surface, significantly different migration times for the strains investigated were observed. Relationships among the observed migration times of six strains, their contact angles, and their zeta potentials were found. Relatively hydrophobic strains exhibited migration times shorter than those of hydrophilic strains. For highly negatively charged strains shorter migration times were found than were found for less negatively charged strains. When the fastest-migrating strain with respect to glass was allowed to migrate along solid surfaces differing in hydrophobicity and charge, no differences in migration times were found. Our findings indicate that strategies to prevent catheter-associated bacteriuria should be based on inhibition of bacterial growth rather than on modifying the physicochemical character of the catheter surface. PMID:1622217

Synthesis of Au@polymer nanohybrids with transited core-shell morphology from concentric to eccentric Emoji-N or Janus nanoparticles.

PubMed

Guarrotxena, Nekane; García, Olga; Quijada-Garrido, Isabel

2018-04-10

The combination of multifunctionality and synergestic effect displayed by hybrid nanoparticles (NPs) has been revealed as an effective stratagem in the development of advanced nanostructures with unique biotechnology and optoelectronic applications. Although important work has been devoted, the demand of facile, versatile and efficient synthetic approach remains still challenging. Herein, we report a feasible and innovative way for polymer-shell assembling onto gold nanoparticles in competitive conditions of hydrophobic/hydrophilic feature and interfacial energy of components to generate core-shell nanohybrids with singular morphologies. The fine control of reaction parameters allows a modulated transformation from concentric to eccentric nanostructure-geometries. In this regard, a rational selection of the components and solvent ratio guarantee the reproducibility and efficiency on hybrid-nanoassembly. Furthermore, the simplicity of the synthetic approach offers the possibility to obtain asymmetric Janus NPs and new morphologies (quizzical-aspheric polymer-shell, named Emoji-N-hybrids) with adjustable surface-coating, leading to new properties and applications that are unavailable to their symmetrical or single components.

Flexible nanohybrid microelectrode based on carbon fiber wrapped by gold nanoparticles decorated nitrogen doped carbon nanotube arrays: In situ electrochemical detection in live cancer cells.

PubMed

Zhang, Yan; Xiao, Jian; Sun, Yimin; Wang, Lu; Dong, Xulin; Ren, Jinghua; He, Wenshan; Xiao, Fei

2018-02-15

The rapidly growing demand for in situ real-time monitoring of chemical information in vitro and in vivo has attracted tremendous research efforts into the design and construction of high-performance biosensor devices. Herein, we develop a new type of flexible nanohybrid microelectrode based on carbon fiber wrapped by gold nanoparticles decorated nitrogen-doped carbon nanotube arrays, and explore its practical application in in situ electrochemical detection of cancer biomarker H 2 O 2 secreted from live cancer cells. Our results demonstrate that carbon fiber material with microscale size and fascinating mechanical properties can be used as a robust and flexible microelectrode substrate in the electrochemical biosensor system. And the highly ordered nitrogen-doped carbon nanotube arrays that grown on carbon fiber possess high surface area-to-volume ratio and abundant active sites, which facilitate the loading of high-density and uniformly dispersed gold nanoparticles on it. Benefited from the unique microstructure and excellent electrocatalytic properties of different components in the nanohybrid fiber microelectrode, an effective electrochemical sensing platform based on it has been built up for the sensitive and selective detection of H 2 O 2 , the detection limit is calculated to be 50nM when the signal-to-noise ratio is 3:1, and the linear dynamic range is up to 4.3mM, with a high sensitivity of 142µAcm -2 mM -1 . These good sensing performances, coupled with its intrinsic mechanical flexibility and biocompatibility, allow for its use in in situ real-time tracking H 2 O 2 secreted from breast cancer cell lines MCF-7 and MBA-MD-231, and evaluating the sensitivity of different cancer cells to chemotherapy or radiotherapy treatments, which hold great promise for clinic application in cancer diagnose and management. Copyright © 2017 Elsevier B.V. All rights reserved.

Ultrasensitive cardiac troponin I antibody based nanohybrid sensor for rapid detection of human heart attack.

PubMed

Bhatnagar, Deepika; Kaur, Inderpreet; Kumar, Ashok

2017-02-01

An ultrasensitive cardiac troponin I antibody conjugated with graphene quantum dots (GQD) and polyamidoamine (PAMAM) nanohybrid modified gold electrode based sensor was developed for the rapid detection of heart attack (myocardial infarction) in human. Screen printed gold (Au) electrode was decorated with 4-aminothiophenol for amine functionalization of the Au surface. These amino groups were further coupled with carboxyl functionalities of GQD with EDC-NHS reaction. In order to enhance the sensitivity of the sensor, PAMAM dendrimer was successively embedded on GQD through carbodiimide coupling to provide ultra-high surface area for antibody immobilization. The activated cardiac troponin I (cTnI) monoclonal antibody was immobilized on PAMAM to form nanoprobe for sensing specific heart attack marker cTnI. Various concentrations of cardiac marker, cTnI were electrochemically measured using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) in human blood serum. The modifications on sensor surface were characterized by FTIR and AFM techniques. The sensor is highly specific to cTnI and showed negligible response to non-specific antigens. The sensitivity of the sensor was 109.23μAcm -2 μg -1 and lower limit of detection of cTnI was found 20fgmL -1 . Copyright © 2016 Elsevier B.V. All rights reserved.

Inhibiting cancer cell hallmark features through nuclear export inhibition.

PubMed

Sun, Qingxiang; Chen, Xueqin; Zhou, Qiao; Burstein, Ezra; Yang, Shengyong; Jia, Da

2016-01-01

Treating cancer through inhibition of nuclear export is one of the best examples of basic research translation into clinical application. Nuclear export factor chromosomal region maintenance 1 (CRM1; Xpo1 and exportin-1) controls cellular localization and function of numerous proteins that are critical for the development of many cancer hallmarks. The diverse actions of CRM1 are likely to explain the broad ranging anti-cancer potency of CRM1 inhibitors observed in pre-clinical studies and/or clinical trials (phase I-III) on both advanced-stage solid and hematological tumors. In this review, we compare and contrast the mechanisms of action of different CRM1 inhibitors, and discuss the potential benefit of unexplored non-covalent CRM1 inhibitors. This emerging field has uncovered that nuclear export inhibition is well poised as an attractive target towards low-toxicity broad-spectrum potent anti-cancer therapy.

The downregulation of Mcl-1 via USP9X inhibition sensitizes solid tumors to Bcl-xl inhibition

PubMed Central

2012-01-01

Background It has been shown in many solid tumors that the overexpression of the pro-survival Bcl-2 family members Bcl-xL and Mcl-1 confers resistance to a variety of chemotherapeutic agents. Mcl-1 is a critical survival protein in a variety of cell lineages and is critically regulated via ubiquitination. Methods The Mcl-1, Bcl-xL and USP9X expression patterns in human lung and colon adenocarcinomas were evaluated via immunohistochemistry. Interaction between USP9X and Mcl-1 was demonstrated by immunoprecipitation-western blotting. The protein expression profiles of Mcl-1, Bcl-xL and USP9X in multiple cancer cell lines were determined by western blotting. Annexin-V staining and cleaved PARP western blotting were used to assay for apoptosis. The cellular toxicities after various treatments were measured via the XTT assay. Results In our current analysis of colon and lung cancer samples, we demonstrate that Mcl-1 and Bcl-xL are overexpressed and also co-exist in many tumors and that the expression levels of both genes correlate with the clinical staging. The downregulation of Mcl-1 or Bcl-xL via RNAi was found to increase the sensitivity of the tumor cells to chemotherapy. Furthermore, our analyses revealed that USP9X expression correlates with that of Mcl-1 in human cancer tissue samples. We additionally found that the USP9X inhibitor WP1130 promotes Mcl-1 degradation and increases tumor cell sensitivity to chemotherapies. Moreover, the combination of WP1130 and ABT-737, a well-documented Bcl-xL inhibitor, demonstrated a chemotherapeutic synergy and promoted apoptosis in different tumor cells. Conclusion Mcl-1, Bcl-xL and USP9X overexpression are tumor survival mechanisms protective against chemotherapy. USP9X inhibition increases tumor cell sensitivity to various chemotherapeutic agents including Bcl-2/Bcl-xL inhibitors. PMID:23171055

Interfacial effects in ZnO nanotubes/needle-structured graphitic diamond nanohybrid for detecting dissolved acetone at room temperature

NASA Astrophysics Data System (ADS)

Kathiravan, Deepa; Huang, Bohr-Ran; Saravanan, Adhimoorthy; Yeh, Chien-Jui; Leou, Keh-Chyang; Lin, I.-Nan

2017-12-01

A high-performance ZnO nanotubes (ZNTs)/needle-structured graphitic diamond (NGD) nanohybrid material was prepared and observed the electrochemical sensing properties of liquid acetone in water. Initially, we synthesized NGD film using bias-enhanced growth (BEG) process. Afterwards, a well-etched ZNTs were spatially grown on the NGD film using simple hydrothermal method, and utilized as sensing material for assemble an electrochemical sensor (via EGFET configuration) operating at room temperature. The systematic investigations depict the ultra-high sensing properties attained from ZNTs grown on NGD film. The NGD film mostly have needle or wire shaped diamond grains, which contributes extremely high electrical conductivity. Furthermore, needle shaped diamond grains cover with multi-layer graphitic material generates conduction channels for ZNTs and leads to enhance the oxygen residuals and species. The material stability and conductivity of NGD as well the defects exist with oxygen vacancies in ZNTs offers superior sensing properties. Thus, the interesting combination of these wide band gap semiconductor materials exhibit high sensor response (89 mV/mL), high stability and long-term reliability (tested after 60 days).

A mass diffusion-based interpretation of the effect of total solids content on solid-state anaerobic digestion of cellulosic biomass.

PubMed

Xu, Fuqing; Wang, Zhi-Wu; Tang, Li; Li, Yebo

2014-09-01

In solid-state anaerobic digestion (SS-AD) of cellulosic biomass, the volumetric methane production rate has often been found to increase with the increase in total solids (TS) content until a threshold is reached, and then to decrease. This phenomenon cannot be explained by conventional understanding derived from liquid anaerobic digestion. This study proposed that the high TS content-caused mass diffusion limitation may be responsible for the observed methane production deterioration. Based on this hypothesis, a new SS-AD model was developed by taking into account the mass diffusion limitation and hydrolysis inhibition. The good agreement between model simulation and the experimental as well as literature data verified that the observed reduction in volumetric methane production rate could be ascribed to hydrolysis inhibition as a result of the mass diffusion limitation in SS-AD. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effects of staining and bleaching on a nanohybrid composite with or without surface sealant

PubMed Central

Halacoglu, Derya Merve; Yamanel, Kıvanc; Basaran, Saffet; Tuncer, Duygu; Celik, Cigdem

2016-01-01

Objective: The effect of different staining solutions and a bleaching procedure on color stability and surface roughness of a nanohybrid resin composite were evaluated with or without liquid resin polishing (RP). Materials and Methods: Ninety-six disc-shaped resin composite specimens (A1 Shade, Z550 Filtek 3M ESPE, St. Paul, MN, USA) were prepared and divided randomly into two groups (n = 48). Liquid RP (BisCover LV, Bisco Inc., Schaumburg, IL, USA) was applied in one group (RP) and not in the other (P). Specimen color and surface roughness were determined using a colorimeter and profilometer, respectively. After baseline measurements, each group was divided into four subgroups (n = 12) for immersion in a control (distilled water) or three different staining solutions (ice tea, red wine, and cola) for 1 week. Color and surface roughness were then reevaluated. After measurements, all specimens were bleached using a 35% hydrogen peroxide gel. The color and surface roughness of the specimens were reevaluated. Statistical Analysis: Data were subjected to an analysis of variance for repeated measurements among the groups (P < 0.05). Results: Staining and bleaching did not change the surface roughness of the RP and P groups (P > 0.05). Discoloration in the red wine group was higher than for the other staining solutions for the RP (P < 0.001) and P groups (P = 0.018). Conclusion: Application of liquid RP did not enhance the color stability and surface roughness of the composite resin restoration. PMID:27403054

Prediction of recrystallization behavior of troglitazone/polyvinylpyrrolidone solid dispersion by solid-state NMR.

PubMed

Ito, Atsutoshi; Watanabe, Tomoyuki; Yada, Shuichi; Hamaura, Takeshi; Nakagami, Hiroaki; Higashi, Kenjirou; Moribe, Kunikazu; Yamamoto, Keiji

2010-01-04

The purpose of this study was to elaborate the relationship between the (13)C CP/MAS NMR spectra and the recrystallization behavior during the storage of troglitazone solid dispersions. The solid dispersions were prepared by either the solvent method or by co-grinding. The recrystallization behavior under storage conditions at 40 degrees C/94% RH was evaluated by the Kolmogorov-Johnson-Mehl-Avrami (KJMA) equation. Solid dispersions prepared by the solvent method or by prolonged grinding brought about inhibition of the nucleation and the nuclei growth at the same time. No differences in the PXRD profiles were found in the samples prepared by the co-grinding and solvent methods, however, (13)C CP/MAS NMR showed significant differences in the spectra. The correlation coefficients using partial least square regression analysis between the PXRD profiles and the apparent nuclei-growth constant or induction period to nucleation were 0.1305 or 0.6350, respectively. In contrast, those between the (13)C CP/MAS NMR spectra and the constant or the period were 0.9916 or 0.9838, respectively. The (13)C CP/MAS NMR spectra had good correlation with the recrystallization kinetic parameters evaluated by the KJMA equation. Consequently, solid-state NMR was judged to be a useful tool for the prediction of the recrystallization behavior of solid dispersions.

Solid anaerobic digestion: State-of-art, scientific and technological hurdles.

PubMed

André, Laura; Pauss, André; Ribeiro, Thierry

2018-01-01

In this paper, a state-of-art about solid anaerobic digestion (AD), focused on recent progress and trends of research is proposed. Solid anaerobic digestion should be the most appropriate process for degradation of by-products with high total solid (TS) content, especially lignocellulosic materials like agricultural waste (straw, manure), household waste and food waste. Solid AD is already widely used in waste water treatment plant for treating plant for sewage sludge but could be more developed for lignocellulosic materials with high TS content. Many research works were carried out in Europe on solid AD, focused on current hurdles (BMP, codigestion, inhibition, microbial population, rheology, water transfers, inoculum, etc.) in order to optimize the solid AD process. In conclusion, hurdles of solid AD process should and must be solved in order to propose better productivity and profitability of such system operating with high TS content (>15%), favouring reliable industrial processes. Copyright © 2017 Elsevier Ltd. All rights reserved.

A facile approach to prepare crumpled CoTMPyP/electrochemically reduced graphene oxide nanohybrid as an efficient electrocatalyst for hydrogen evolution reaction

NASA Astrophysics Data System (ADS)

Ma, Juanjuan; Liu, Lin; Chen, Qian; Yang, Min; Wang, Danping; Tong, Zhiwei; Chen, Zhong

2017-03-01

Elaborate design and synthesis of efficient and stable non-Pt electrocatalysts for some renewable energy related conversion/storage processes are one of the major goals of sustainable chemistry. Herein, we report a facile method to fabricate Co porphyrin functionalized electrochemically reduced graphene oxide (CoTMPyP/ERGO) thin film by direct assembly of oppositely charged tetrakis(N-methylpyridyl) porphyrinato cobalt (CoTMPyP) and GO nanosheets under mild conditions followed by an electrochemical reduction procedure. STEM analysis confirms that CoTMPyP nanoaggregates are homogeneously distributed over the graphene surface. The electrochemical properties of CoTMPyP/ERGO were investigated by cyclic voltammetry, linear sweep voltammetry and electrochemical impedance spectroscopy. The results demonstrate that CoTMPyP/ERGO nanohybrid film can serve as excellent electrocatalyst for hydrogen evolution in alkaline solution with high activity and stability. The intimate contact and efficient electron transfer between CoTMPyP and ERGO, as well as the crumpled structure, contribute to the improvement of the electrocatalytic performance.

Transport and Retention of Carboxymethylcellulose-Modified Carbon Nanotube-Magnetite Nanohybrids in Water-Saturated Porous Media

NASA Astrophysics Data System (ADS)

Wang, D.; Su, C.

2017-12-01

Carbon-metal oxide nanohybrids (NHs) are increasingly recognized as the next-generation, promising group of nanomaterials for solving emerging environmental issues and challenges. This research, for the first time, systematically explored the transport and retention of the multifunctional carbon nanotube-magnetite (CNT-Fe3O4) NHs in water-saturated porous media under environmentally relevant physicochemical conditions. An environment-benign macromolecule, carboxymethylcellulose (CMC), was employed to stabilize the NHs. Classical Derjaguin-Landau-Verwey-Overbeek (DLVO) theory and colloid transport model were used to describe the transport and retention of the NHs. Our results showed that transport of the magnetic CNT-Fe3O4 NHs was lower than that of the parent CNT due to greater aggregation (induced by magnetic attraction) during transport. The DLVO theory well-interpreted the NHs' transport; and secondary minimum played dominant roles in NHs' retention. A novel transport feature, an initial low and following sharp peaks occurred frequently in the NHs' breakthrough curves; and the magnitude and location of both transport peaks varied with different experimental conditions due to the interplay between variability of the fluid viscosity and aggregation-dispersion nature of the NHs. Very promisingly, the estimated maximum transport distance of NHs using the Tufenkji-Elimelech equation ranged between 0.38-46 m, supporting the feasibility of employing the magnetically recyclable CNT-Fe3O4 NHs for in-situ nanoremediation of contaminated soils, sediment aquifers, and groundwater.

Pseudomonas aeruginosa inhibits the growth of Cryptococcus species.

PubMed

Rella, Antonella; Yang, Mo Wei; Gruber, Jordon; Montagna, Maria Teresa; Luberto, Chiara; Zhang, Yong-Mei; Del Poeta, Maurizio

2012-06-01

Pseudomonas aeruginosa is a ubiquitous and opportunistic bacterium that inhibits the growth of different microorganisms, including Gram-positive bacteria and fungi such as Candida spp. and Aspergillus fumigatus. In this study, we investigated the interaction between P. aeruginosa and Cryptococcus spp. We found that P. aeruginosa PA14 and, to a lesser extent, PAO1 significantly inhibited the growth of Cryptococcus spp. The inhibition of growth was observed on solid medium by the visualization of a zone of inhibition of yeast growth and in liquid culture by viable cell counting. Interestingly, such inhibition was only observed when P. aeruginosa and Cryptococcus were co-cultured. Minimal inhibition was observed when cell-cell contact was prevented using a separation membrane, suggesting that cell contact is required for inhibition. Using mutant strains of Pseudomonas quinoline signaling, we showed that P. aeruginosa inhibited the growth of Cryptococcus spp. by producing antifungal molecules pyocyanin, a redox-active phenazine, and 2-heptyl-3,4-dihydroxyquinoline (PQS), an extracellular quorum-sensing signal. Because both P. aeruginosa and Cryptococcus neoformans are commonly found in lung infections of immunocompromised patients, this study may have important implication for the interaction of these microbes in both an ecological and a clinical point of view.

Human milk glycoconjugates that inhibit pathogens.

PubMed

Newburg, D S

1999-02-01

Breast-fed infants have lower incidence of diarrhea, respiratory disease, and otitis media. The protection by human milk has long been attributed to the presence of secretory IgA. However, human milk contains large numbers and amounts of complex carbohydrates, including glycoproteins, glycolipids, glycosaminoglycans, mucins, and especially oligosaccharides. The oligosaccharides comprise the third most abundant solid constituent of human milk, and contain a myriad of structures. Complex carbohydrate moieties of glycoconjugates and oligosaccharides are synthesized by the many glycosyltransferases in the mammary gland; those with homology to cell surface glycoconjugate pathogen receptors may inhibit pathogen binding, thereby protecting the nursing infant. Several examples are reviewed: A fucosyloligosaccharide inhibits the diarrheagenic effect of stable toxin of Escherichia coli. A different fucosyloligosaccharide inhibits infection by Campylobacter jejuni. Binding of Streptococcus pneumoniae and of enteropathogenic E. coli to their respective receptors is inhibited by human milk oligosaccharides. The 46-kD glycoprotein, lactadherin, inhibits rotavirus binding and infectivity. Low levels of lactadherin in human milk are associated with a higher incidence of symptomatic rotavirus in breast-fed infants. A mannosylated glycopeptide inhibits binding by enterohemorrhagic E. coli. A glycosaminoglycan inhibits binding of gp120 to CD4, the first step in HIV infection. Human milk mucin inhibits binding by S-fimbriated E. coli. The ganglioside, GM1, reduces diarrhea production by cholera toxin and labile toxin of E. coli. The neutral glycosphingolipid, Gb3, binds to Shigatoxin. Thus, many complex carbohydrates of human milk may be novel antipathogenic agents, and the milk glycoconjugates and oligosaccharides may be a major source of protection for breastfeeding infants.

Pre-separation of ammonium content during high solid thermal-alkaline pretreatment to mitigate ammonia inhibition: Kinetics and feasibility analysis.

PubMed

Zhuo, Yang; Han, Yun; Qu, Qiliang; Cao, Yuqin; Peng, Dangcong; Li, Yuyou

2018-08-01

The feasibility of ammonia pre-separation during the thermal-alkaline pretreatment (TAP) of waste activated sludge was evaluated to mitigate ammonia inhibition during high solid anaerobic digestion (HSAD). The results showed that the TAP increased the organics hydrolysis rate as much as 77% compared to the thermal hydrolysis pretreatment (THP). The production and separation of the ammonia during the TAP exhibited a linear relationship with the hydrolysis of organics and the Emerson model. The pre-separation ratio of the free ammonia nitrogen exceeded 98.00% at a lime dosage exceeding 0.021 g CaO/g TS. However, the separation ratio of the total ammonia nitrogen (TAN) was hindered by its production ratio. Compared to the THP, the TAP increased the methane production rate under similar production yield. A mass flow analysis indicated that the TAP-HSAD process reduced the volume of the digester compared to the THP-HSAD process and the recirculated HSAD-TAP process recovered 45% of the nitrogen in the waste activated sludge. Copyright © 2018 Elsevier Ltd. All rights reserved.

Scalable synthesis of freestanding sandwich-structured graphene/polyaniline/graphene nanocomposite paper for flexible all-solid-state supercapacitor.

PubMed

Xiao, Fei; Yang, Shengxiong; Zhang, Zheye; Liu, Hongfang; Xiao, Junwu; Wan, Lian; Luo, Jun; Wang, Shuai; Liu, Yunqi

2015-03-23

We reported a scalable and modular method to prepare a new type of sandwich-structured graphene-based nanohybrid paper and explore its practical application as high-performance electrode in flexible supercapacitor. The freestanding and flexible graphene paper was firstly fabricated by highly reproducible printing technique and bubbling delamination method, by which the area and thickness of the graphene paper can be freely adjusted in a wide range. The as-prepared graphene paper possesses a collection of unique properties of highly electrical conductivity (340 S cm(-1)), light weight (1 mg cm(-2)) and excellent mechanical properties. In order to improve its supercapacitive properties, we have prepared a unique sandwich-structured graphene/polyaniline/graphene paper by in situ electropolymerization of porous polyaniline nanomaterials on graphene paper, followed by wrapping an ultrathin graphene layer on its surface. This unique design strategy not only circumvents the low energy storage capacity resulting from the double-layer capacitor of graphene paper, but also enhances the rate performance and cycling stability of porous polyaniline. The as-obtained all-solid-state symmetric supercapacitor exhibits high energy density, high power density, excellent cycling stability and exceptional mechanical flexibility, demonstrative of its extensive potential applications for flexible energy-related devices and wearable electronics.

Scalable Synthesis of Freestanding Sandwich-structured Graphene/Polyaniline/Graphene Nanocomposite Paper for Flexible All-Solid-State Supercapacitor

NASA Astrophysics Data System (ADS)

Xiao, Fei; Yang, Shengxiong; Zhang, Zheye; Liu, Hongfang; Xiao, Junwu; Wan, Lian; Luo, Jun; Wang, Shuai; Liu, Yunqi

2015-03-01

We reported a scalable and modular method to prepare a new type of sandwich-structured graphene-based nanohybrid paper and explore its practical application as high-performance electrode in flexible supercapacitor. The freestanding and flexible graphene paper was firstly fabricated by highly reproducible printing technique and bubbling delamination method, by which the area and thickness of the graphene paper can be freely adjusted in a wide range. The as-prepared graphene paper possesses a collection of unique properties of highly electrical conductivity (340 S cm-1), light weight (1 mg cm-2) and excellent mechanical properties. In order to improve its supercapacitive properties, we have prepared a unique sandwich-structured graphene/polyaniline/graphene paper by in situ electropolymerization of porous polyaniline nanomaterials on graphene paper, followed by wrapping an ultrathin graphene layer on its surface. This unique design strategy not only circumvents the low energy storage capacity resulting from the double-layer capacitor of graphene paper, but also enhances the rate performance and cycling stability of porous polyaniline. The as-obtained all-solid-state symmetric supercapacitor exhibits high energy density, high power density, excellent cycling stability and exceptional mechanical flexibility, demonstrative of its extensive potential applications for flexible energy-related devices and wearable electronics.

Scalable Synthesis of Freestanding Sandwich-structured Graphene/Polyaniline/Graphene Nanocomposite Paper for Flexible All-Solid-State Supercapacitor

PubMed Central

Xiao, Fei; Yang, Shengxiong; Zhang, Zheye; Liu, Hongfang; Xiao, Junwu; Wan, Lian; Luo, Jun; Wang, Shuai; Liu, Yunqi

2015-01-01

We reported a scalable and modular method to prepare a new type of sandwich-structured graphene-based nanohybrid paper and explore its practical application as high-performance electrode in flexible supercapacitor. The freestanding and flexible graphene paper was firstly fabricated by highly reproducible printing technique and bubbling delamination method, by which the area and thickness of the graphene paper can be freely adjusted in a wide range. The as-prepared graphene paper possesses a collection of unique properties of highly electrical conductivity (340 S cm−1), light weight (1 mg cm−2) and excellent mechanical properties. In order to improve its supercapacitive properties, we have prepared a unique sandwich-structured graphene/polyaniline/graphene paper by in situ electropolymerization of porous polyaniline nanomaterials on graphene paper, followed by wrapping an ultrathin graphene layer on its surface. This unique design strategy not only circumvents the low energy storage capacity resulting from the double-layer capacitor of graphene paper, but also enhances the rate performance and cycling stability of porous polyaniline. The as-obtained all-solid-state symmetric supercapacitor exhibits high energy density, high power density, excellent cycling stability and exceptional mechanical flexibility, demonstrative of its extensive potential applications for flexible energy-related devices and wearable electronics. PMID:25797022

Can Chlorella pyrenoidosa be a bioindicator for hazardous solid waste detoxification?

PubMed

Hu, Li-Fang; Long, Yu-Yang; Shen, Dong-Sheng; Jiang, Chen-Jing

2012-02-01

Four kinds of solid waste residue (SWR, S1 to S4) from different stages in a sequential detoxification process were chosen. The biotoxicity of the leachates from S1 to S4 was tested by Chlorella pyrenoidosa. The growth inhibition, the chlorophyll a (chla) and chlorophyll b (chlb) concentrations, and the ultrastructural morphology of cells of C. pyrenoidosa were studied. It shows that the growth inhibition of C. pyrenoidosa significantly increased with increasing leachate concentration when exposed to the leachates from S1, S2, S3, and S4, respectively. It well reflects the toxicity difference of leachate from SWR at different treatment stages, namely S1>S2>S3>S4. Correspondingly, the chla and chlb concentrations of C. pyrenoidosa increased gradually as SWR was treated deeply. Leachate disrupted chlorophyll synthesis and inhibited cell growth. The changing of the ultrastructural morphology of cells under different leachate exposures, such as volume of chloroplasts and quantity of thylakoids reducing, confirmed the toxicity decrease of leachates from different stages. C. pyrenoidosa is a good bioindicator for hazardous solid waste detoxification. The EC(50) at difference scenarios also suggests that it was feasible to estimate ecological toxicity of leachates to C. pyrenoidosa after exposure times of 72h. C. pyrenoidosa can be introduced to evaluate the effect of hazardous solid waste disposal by biotoxicity assessment. Copyright © 2011 Elsevier B.V. All rights reserved.

C-104 high-level waste solids: Washing/leaching and solubility versus temperature studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

GJ Lumetta; DJ Bates; JP Bramson

This report describes the results of a test conducted by Battelle to assess the effects of inhibited water washing and caustic leaching on the composition of the C-104 HLW solids. The objective of this work was to determine the composition of the C-104 solids remaining after washing with 0.01 M NaOH or leaching with 3 M NaOH. Another objective of this test was to determine the solubility of the C-104 solids as a function of temperature. The work was conducted according to test plan BNFL-TP-29953-8, Rev. 0, ``Determination of the Solubility of HLW Sludge Solids.

Carbon Nitride-Aromatic Diimide-Graphene Nanohybrids: Metal-Free Photocatalysts for Solar-to-Hydrogen Peroxide Energy Conversion with 0.2% Efficiency.

PubMed

Kofuji, Yusuke; Isobe, Yuki; Shiraishi, Yasuhiro; Sakamoto, Hirokatsu; Tanaka, Shunsuke; Ichikawa, Satoshi; Hirai, Takayuki

2016-08-10

Solar-to-chemical energy conversion is a challenging subject for renewable energy storage. In the past 40 years, overall water splitting into H2 and O2 by semiconductor photocatalysis has been studied extensively; however, they need noble metals and extreme care to avoid explosion of the mixed gases. Here we report that generating hydrogen peroxide (H2O2) from water and O2 by organic semiconductor photocatalysts could provide a new basis for clean energy storage without metal and explosion risk. We found that carbon nitride-aromatic diimide-graphene nanohybrids prepared by simple hydrothermal-calcination procedure produce H2O2 from pure water and O2 under visible light (λ > 420 nm). Photoexcitation of the semiconducting carbon nitride-aromatic diimide moiety transfers their conduction band electrons to graphene and enhances charge separation. The valence band holes on the semiconducting moiety oxidize water, while the electrons on the graphene moiety promote selective two-electron reduction of O2. This metal-free system produces H2O2 with solar-to-chemical energy conversion efficiency 0.20%, comparable to the highest levels achieved by powdered water-splitting photocatalysts.

Inhibition of precipitation and aggregation of metacinnabar (mercuric sulfide) by dissolved organic matter isolated from the Florida Everglades

USGS Publications Warehouse

Ravichandran, M.; Aiken, G.R.; Ryan, J.N.; Reddy, M.M.

1999-01-01

Precipitation and aggregation of metacinnabar (black HgS) was inhibited in the presence of low concentrations (???3 mg C/L) of humic fractions of dissolved organic matter (DOM) isolated from the Florida Everglades. At low Hg concentrations (??? x 10-8 M), DOM prevented the precipitation of metacinnabar. At moderate Hg concentrations (5 x 10-5 M), DOM inhibited the aggregation of colloidal metacinnabar (Hg passed through a 0.1 ??m filter but was removed by centrifugation). At Hg concentrations greater than 5 x 10-4 M, mercury formed solid metacinnabar particles that were removed from solution by a 0.1 ??m filter. Organic matter rich in aromatic moleties was preferentially removed with the solid. Hydrophobic organic acids (humic and fulvic acids) inhibited aggregation better than hydrophilic organic acids. The presence of chloride, acetate, salicylate, EDTA, and cysteine did not inhibit the precipitation or aggregation of metacinnabar. Calcium enhanced metacinnabar aggregation even in the presence of DOM, but the magnitude of the effect was dependent on the concentrations of DOM, Hg, and Ca. Inhibition of metacinnabar precipitation appears to be a result of strong DOM-Hg binding. Prevention of aggregation of colloidal particles appears to be caused by adsorption of DOM and electrostatic repulsion.Precipitation and aggregation of metacinnabar (black HgS) was inhibited in the presence of low concentrations (???3 mg C/L) of humic fractions of dissolved organic matter (DOM) isolated from the Florida Everglades. At low Hg concentrations (???5??10-8 M), DOM prevented the precipitation of metacinnabar. At moderate Hg concentrations (5??10-5 M), DOM inhibited the aggregation of colloidal metacinnabar (Hg passed through a 0.1 ??m filter but was removed by centrifugation). At Hg concentrations greater than 5??10-4 M, mercury formed solid metacinnabar particles that were removed from solution by a 0.1 ??m filter. Organic matter rich in aromatic moieties was preferentially

Wrapping cytochrome c around single-wall carbon nanotube: engineered nanohybrid building blocks for infrared detection at high quantum efficiency

PubMed Central

Gong, Youpin; Liu, Qingfeng; Wilt, Jamie Samantha; Gong, Maogang; Ren, Shenqiang; Wu, Judy

2015-01-01

Biomolecule cytochrome c (Cty c), a small molecule of a chain of amino acids with extraordinary electron transport, was helically wrapped around a semiconductive single-wall carbon nanotube (s-SWCNT) to form a molecular building block for uncooled infrared detection with two uniquely designed functionalities: exciton dissociation to free charge carriers at the heterojunction formed on the s-SWCNT/Cty c interface and charge transport along the electron conducting chain of Cty c (acceptor) and hole conducting channel through s-SWCNT (donor). Such a design aims at addressing the long-standing challenges in exciton dissociation and charge transport in an SWCNT network, which have bottlenecked development of photonic SWCNT-based infrared detectors. Using these building blocks, uncooled s-SWCNT/Cyt c thin film infrared detectors were synthesized and shown to have extraordinary photoresponsivity up to 0.77 A W−1 due to a high external quantum efficiency (EQE) in exceeding 90%, which represents a more than two orders of magnitude enhancement than the best previously reported on CNT-based infrared detectors with EQE of only 1.72%. From a broad perspective, this work on novel s-SWCNT/Cyt c nanohybrid infrared detectors has developed a successful platform of engineered carbon nanotube/biomolecule building blocks with superior properties for optoelectronic applications. PMID:26066737

Wrapping cytochrome c around single-wall carbon nanotube: engineered nanohybrid building blocks for infrared detection at high quantum efficiency.

PubMed

Gong, Youpin; Liu, Qingfeng; Wilt, Jamie Samantha; Gong, Maogang; Ren, Shenqiang; Wu, Judy

2015-06-11

Biomolecule cytochrome c (Cty c), a small molecule of a chain of amino acids with extraordinary electron transport, was helically wrapped around a semiconductive single-wall carbon nanotube (s-SWCNT) to form a molecular building block for uncooled infrared detection with two uniquely designed functionalities: exciton dissociation to free charge carriers at the heterojunction formed on the s-SWCNT/Cty c interface and charge transport along the electron conducting chain of Cty c (acceptor) and hole conducting channel through s-SWCNT (donor). Such a design aims at addressing the long-standing challenges in exciton dissociation and charge transport in an SWCNT network, which have bottlenecked development of photonic SWCNT-based infrared detectors. Using these building blocks, uncooled s-SWCNT/Cyt c thin film infrared detectors were synthesized and shown to have extraordinary photoresponsivity up to 0.77 A W(-1) due to a high external quantum efficiency (EQE) in exceeding 90%, which represents a more than two orders of magnitude enhancement than the best previously reported on CNT-based infrared detectors with EQE of only 1.72%. From a broad perspective, this work on novel s-SWCNT/Cyt c nanohybrid infrared detectors has developed a successful platform of engineered carbon nanotube/biomolecule building blocks with superior properties for optoelectronic applications.

Piezoelectric coupling in a field-effect transistor with a nanohybrid channel of ZnO nanorods grown vertically on graphene.

PubMed

Quang Dang, Vinh; Kim, Do-Il; Thai Duy, Le; Kim, Bo-Yeong; Hwang, Byeong-Ung; Jang, Mi; Shin, Kyung-Sik; Kim, Sang-Woo; Lee, Nae-Eung

2014-12-21

Piezoelectric coupling phenomena in a graphene field-effect transistor (GFET) with a nano-hybrid channel of chemical-vapor-deposited Gr (CVD Gr) and vertically aligned ZnO nanorods (NRs) under mechanical pressurization were investigated. Transfer characteristics of the hybrid channel GFET clearly indicated that the piezoelectric effect of ZnO NRs under static or dynamic pressure modulated the channel conductivity (σ) and caused a positive shift of 0.25% per kPa in the Dirac point. However, the GFET without ZnO NRs showed no change in either σ or the Dirac point. Analysis of the Dirac point shifts indicated transfer of electrons from the CVD Gr to ZnO NRs due to modulation of their interfacial barrier height under pressure. High responsiveness of the hybrid channel device with fast response and recovery times was evident in the time-dependent behavior at a small gate bias. In addition, the hybrid channel FET could be gated by mechanical pressurization only. Therefore, a piezoelectric-coupled hybrid channel GFET can be used as a pressure-sensing device with low power consumption and a fast response time. Hybridization of piezoelectric 1D nanomaterials with a 2D semiconducting channel in FETs enables a new design for future nanodevices.

Highly Conductive Solid-State Hybrid Electrolytes Operating at Subzero Temperatures.

PubMed

Kwon, Taeyoung; Choi, Ilyoung; Park, Moon Jeong

2017-07-19

We report a unique, highly conductive, dendrite-inhibited, solid-state polymer electrolyte platform that demonstrates excellent battery performance at subzero temperatures. A design based on functionalized inorganic nanoparticles with interconnected mesopores that contain surface nitrile groups is the key to this development. Solid-state hybrid polymer electrolytes based on succinonitrile (SN) electrolytes and porous nanoparticles were fabricated via a simple UV-curing process. SN electrolytes were effectively confined within the mesopores. This stimulated favorable interactions with lithium ions, reduced leakage of SN electrolytes over time, and improved mechanical strength of membranes. Inhibition of lithium dendrite growth and improved electrochemical stability up to 5.2 V were also demonstrated. The hybrid electrolytes exhibited high ionic conductivities of 2 × 10 -3 S cm -1 at room temperature and >10 -4 S cm -1 at subzero temperatures, leading to stable and improved battery performance at subzero temperatures. Li cells made with lithium titanate anodes exhibited stable discharge capacities of 151 mAh g -1 at temperatures below -10 °C. This corresponds to 92% of the capacity achieved at room temperature (164 mAh g -1 ). Our work represents a significant advance in solid-state polymer electrolyte technology and far exceeds the performance available with conventional polymeric battery separators.

Dramatically different kinetics and mechanism at solid/liquid and solid/gas interfaces for catalytic isopropanol oxidation over size-controlled platinum nanoparticles.

PubMed

Wang, Hailiang; Sapi, Andras; Thompson, Christopher M; Liu, Fudong; Zherebetskyy, Danylo; Krier, James M; Carl, Lindsay M; Cai, Xiaojun; Wang, Lin-Wang; Somorjai, Gabor A

2014-07-23

We synthesize platinum nanoparticles with controlled average sizes of 2, 4, 6, and 8 nm and use them as model catalysts to study isopropanol oxidation to acetone in both the liquid and gas phases at 60 °C. The reaction at the solid/liquid interface is 2 orders of magnitude slower than that at the solid/gas interface, while catalytic activity increases with the size of platinum nanoparticles for both the liquid-phase and gas-phase reactions. The activation energy of the gas-phase reaction decreases with the platinum nanoparticle size and is in general much higher than that of the liquid-phase reaction which is largely insensitive to the size of catalyst nanoparticles. Water substantially promotes isopropanol oxidation in the liquid phase. However, it inhibits the reaction in the gas phase. The kinetic results suggest different mechanisms between the liquid-phase and gas-phase reactions, correlating well with different orientations of IPA species at the solid/liquid interface vs the solid/gas interface as probed by sum frequency generation vibrational spectroscopy under reaction conditions and simulated by computational calculations.

Silver nanoparticle (AgNPs) doped gum acacia-gelatin-silica nanohybrid: an effective support for diastase immobilization.

PubMed

Singh, Vandana; Ahmed, Shakeel

2012-03-01

An effective carrier matrix for diastase alpha amylase immobilization has been fabricated by gum acacia-gelatin dual templated polymerization of tetramethoxysilane. Silver nanoparticle (AgNp) doping to this hybrid could significantly enhance the shelf life of the impregnated enzyme while retaining its full bio-catalytic activity. The doped nanohybrid has been characterized as a thermally stable porous material which also showed multipeak photoluminescence under UV excitation. The immobilized diastase alpha amylase has been used to optimize the conditions for soluble starch hydrolysis in comparison to the free enzyme. The optimum pH for both immobilized and free enzyme hydrolysis was found to be same (pH=5), indicating that the immobilization made no major change in enzyme conformation. The immobilized enzyme showed good performance in wide temperature range (from 303 to 323 K), 323 K being the optimum value. The kinetic parameters for the immobilized, (K(m)=10.30 mg/mL, V(max)=4.36 μmol mL(-1)min(-1)) and free enzyme (K(m)=8.85 mg/mL, V(max)=2.81 μmol mL(-1)min(-1)) indicated that the immobilization improved the overall stability and catalytic property of the enzyme. The immobilized enzyme remained usable for repeated cycles and did not lose its activity even after 30 days storage at 40°C, while identically synthesized and stored silver undoped hybrid lost its ~31% activity in 48 h. Present study revealed the hybrids to be potentially useful for biomedical and optical applications. Copyright © 2011 Elsevier B.V. All rights reserved.

Dual Inhibition of the Epidermal Growth Factor Receptor Pathway with Cetuximab and Erlotinib: A Phase I Study in Patients with Advanced Solid Malignancies

PubMed Central

Guarino, Michael J.; Schneider, Charles J.; Hosford, Martha A.; Brahmer, Julie R.; Rudin, Charles M.; Finckenstein, Friedrich Graf; Philip-Norton, Robyn E.; Lu, Haolan; Weber, Martin R.; Ettinger, David S.

2017-01-01

Purpose To determine the optimal dose of the antiepidermal growth factor receptor (EGFR) monoclonal antibody cetuximab that can be safely administered in combination with a standard daily dose of erlotinib in patients with advanced solid malignancies. Patients and Methods Patients with advanced solid malignancies who had failed standard chemotherapies received escalating doses of cetuximab without a loading dose (100, 200, 250 mg/m2 i.v. weekly) in combination with a fixed dose of erlotinib (150 mg daily orally) until disease progression or unacceptable toxicity. Results Twenty-two patients were treated, including 14 patients (64%) with non-small cell lung cancer. Twenty patients received combination treatment at the highest dose level for a median of 5.5 weeks (range, 1–31 weeks). One dose-limiting toxicity was observed: grade 3 skin rash. Overall, the most common adverse events (any grade, grade 3/4) were consistent with the safety profiles of the individual drugs: acneform rash (100%, 9%), diarrhea (77%, 5%), and hypomagnesemia (59%, 12%). Seven of 18 evaluable patients (38.9%) had stable disease lasting for a median of 16.6 weeks (range, 6.1–25.1 weeks). Conclusion Dual EGFR inhibition with cetuximab and erlotinib is feasible; the observed toxicities were manageable and consistent with the safety profiles of the individual drugs. The recommended doses for phase II studies are 250 mg/m2 i.v. weekly for cetuximab and 150 mg daily orally for erlotinib. PMID:19182243

Inhibition of the solid state transformation of carbamazepine in aqueous solution: impact of polymeric properties.

PubMed

Gift, Alan D; Hettenbaugh, Jacob A; Quandahl, Rachel A; Mapes, Madison

2017-11-06

The effects of polymers on the anhydrate-to-hydrate transformation of carbamazepine (CBZ) was investigated. The three types of polymers studied were polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA) and substituted celluloses which included hydroxypropyl methylcellulose (HPMC) and methylcellulose (MC). Anhydrous CBZ was added to dilute aqueous polymer solutions and Raman spectroscopy measurements were collected to monitor the kinetics of the solution-mediated transformation to CBZ dihydrate. Polymers exhibiting the greatest inhibition were able to reduce the growth phase of the solution-mediated transformation and change the habit of the hydrate crystal indicating polymer adsorption to the hydrate crystal surface as the mechanism of inhibition. The results of the various polymers showed that short chain substituted celluloses (HPMC and MC) inhibited the CBZ transformation to a much greater extent than longer chains. The same trend was observed for PVP and PVA, but to a lesser extent. These chain length effects were attributed to changes in polymer confirmation when adsorbed on the crystal surface. Additionally, decreasing the percentage of hydroxyl groups on the PVA polymer backbone reduced the ability of the polymer to inhibit the transformation and changing the degree of substitutions of methyl and hydroxypropyl groups on the cellulosic polymer backbone had no effect on the transformation.

Stretchable, Transparent, Ultrasensitive, and Patchable Strain Sensor for Human-Machine Interfaces Comprising a Nanohybrid of Carbon Nanotubes and Conductive Elastomers.

PubMed

Roh, Eun; Hwang, Byeong-Ung; Kim, Doil; Kim, Bo-Yeong; Lee, Nae-Eung

2015-06-23

Interactivity between humans and smart systems, including wearable, body-attachable, or implantable platforms, can be enhanced by realization of multifunctional human-machine interfaces, where a variety of sensors collect information about the surrounding environment, intentions, or physiological conditions of the human to which they are attached. Here, we describe a stretchable, transparent, ultrasensitive, and patchable strain sensor that is made of a novel sandwich-like stacked piezoresisitive nanohybrid film of single-wall carbon nanotubes (SWCNTs) and a conductive elastomeric composite of polyurethane (PU)-poly(3,4-ethylenedioxythiophene) polystyrenesulfonate ( PSS). This sensor, which can detect small strains on human skin, was created using environmentally benign water-based solution processing. We attributed the tunability of strain sensitivity (i.e., gauge factor), stability, and optical transparency to enhanced formation of percolating networks between conductive SWCNTs and PEDOT phases at interfaces in the stacked PU-PEDOT:PSS/SWCNT/PU-PEDOT:PSS structure. The mechanical stability, high stretchability of up to 100%, optical transparency of 62%, and gauge factor of 62 suggested that when attached to the skin of the face, this sensor would be able to detect small strains induced by emotional expressions such as laughing and crying, as well as eye movement, and we confirmed this experimentally.

Solid-phase extraction-gas chromatography and solid-phase extraction-gas chromatography-mass spectrometry determination of corrosion inhibiting long-chain primary alkyl amines in chemical treatment of boiler water in water-steam systems of power plants.

PubMed

Kusch, Peter; Knupp, Gerd; Hergarten, Marcus; Kozupa, Marian; Majchrzak, Maria

2006-04-28

Gas chromatography with simultaneous flame-ionization detection (FID) and a nitrogen-phosphorus detection (NPD) as well as gas chromatography-mass spectrometry (GC/MS) has been used to characterize long-chain primary alkyl amines after derivatization with trifluoroacetic anhydride (TFAA). Electron impact ionization- (EI) and negative chemical ionization (NCI) mass spectra of trifluoroacetylated derivatives of the identified tert-octadecylamines are presented for the first time. The corrosion inhibiting alkyl amines were applied in a water-steam circuit of energy systems in the power industry. Solid-phase extraction (SPE) with octadecyl bonded silica (C18) sorbents followed by gas chromatography were used for quantification of the investigated tert-octadecylamines in boiler water, superheated steam and condensate samples from the power plant. The estimated values were: 89 microg l(-1)(n = 5, RSD = 7.8%), 45 microg l(-1) (n = 5, RSD = 5.4%) and 37 microg l(-1)(n = 5, RSD = 2.3%), respectively.

Impact of surfactants on the crystallization of aqueous suspensions of celecoxib amorphous solid dispersion spray dried particles.

PubMed

Chen, Jie; Ormes, James D; Higgins, John D; Taylor, Lynne S

2015-02-02

Amorphous solid dispersions are frequently prepared by spray drying. It is important that the resultant spray dried particles do not crystallize during formulation, storage, and upon administration. The goal of the current study was to evaluate the impact of surfactants on the crystallization of celecoxib amorphous solid dispersions (ASD), suspended in aqueous media. Solid dispersions of celecoxib with hydroxypropylmethylcellulose acetate succinate were manufactured by spray drying, and aqueous suspensions were prepared by adding the particles to acidified media containing various surfactants. Nucleation induction times were evaluated for celecoxib in the presence and absence of surfactants. The impact of the surfactants on drug and polymer leaching from the solid dispersion particles was also evaluated. Sodium dodecyl sulfate and Polysorbate 80 were found to promote crystallization from the ASD suspensions, while other surfactants including sodium taurocholate and Triton X100 were found to inhibit crystallization. The promotion or inhibition of crystallization was found to be related to the impact of the surfactant on the nucleation behavior of celecoxib, as well as the tendency to promote leaching of the drug from the ASD particle into the suspending medium. It was concluded that surfactant choice is critical to avoid failure of amorphous solid dispersions through crystallization of the drug.

Continuous high-solids anaerobic co-digestion of organic solid wastes under mesophilic conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Dong-Hoon; Oh, Sae-Eun, E-mail: saeun@hanbat.ac.kr

2011-09-15

Highlights: > High-solids (dry) anaerobic digestion is attracting a lot of attention these days. > One reactor was fed with food waste (FW) and paper waste. > Maximum biogas production rate of 5.0 m{sup 3}/m{sup 3}/d was achieved at HRT 40 d and 40% TS. > The other reactor was fed with FW and livestock waste (LW). > Until a 40% LW content increase, the reactor exhibited a stable performance. - Abstract: With increasing concerns over the limited capacity of landfills, conservation of resources, and reduction of CO{sub 2} emissions, high-solids (dry) anaerobic digestion of organic solid waste (OSW) ismore » attracting a great deal of attention these days. In the present work, two dry anaerobic co-digestion systems fed with different mixtures of OSW were continuously operated under mesophilic conditions. Dewatered sludge cake was used as a main seeding source. In reactor (I), which was fed with food waste (FW) and paper waste (PW), hydraulic retention time (HRT) and solid content were controlled to find the maximum treatability. At a fixed solid content of 30% total solids (TS), stable performance was maintained up to an HRT decrease to 40 d. However, the stable performance was not sustained at 30 d HRT, and hence, HRT was increased to 40 d again. In further operation, instead of decreasing HRT, solid content was increased to 40% TS, which was found to be a better option to increase the treatability. The biogas production rate (BPR), CH{sub 4} production yield (MPY) and VS reduction achieved in this condition were 5.0 m{sup 3}/m{sup 3}/d, 0.25 m{sup 3} CH{sub 4}/g COD{sub added}, and 80%, respectively. Reactor (II) was fed with FW and livestock waste (LW), and LW content was increased during the operation. Until a 40% LW content increase, reactor (II) exhibited a stable performance. A BPR of 1.7 m{sup 3}/m{sup 3}/d, MPY of 0.26 m{sup 3} CH{sub 4}/g COD{sub added}, and VS reduction of 72% was achieved at 40% LW content. However, when the LW content was increased to

Solid state photochemistry of polycarbonates

NASA Technical Reports Server (NTRS)

Gupta, A.; Rembaum, A.; Moacanin, J.

1978-01-01

The quantum yield of photoFries rearrangement in a polycarbonate film has been analyzed as a function of temperature and humidity on the basis of previously reported (Koyler and Mann, 1977) experimental data. Results indicate that in the homogeneous amorphous phase, photoFries rearrangement is a concerted process proceeding either from the pi star reversed arrow n singlet, in which case it must be subject to considerable self quenching, or from a triplet, presumably the first triplet since the lifetime of higher triplets is expected to be very short in the solid phase. If the parent excited state is the first triplet, chain scission is possibly an independent process, probably occurring from the pi star reversed arrow n singlet. Evidence of chain scission on photodegradation in the solid state includes loss of C-O and C-C bond intensities revealed in the Fourier transform infrared spectra, gel permeation chromotography elution profiles of degraded film samples dissolved in CHCl3, and a decrease in tensile strength and T sub g as photodegradation proceeds. Chain scission is apparently inhibited as photoFries products accumulate.

Suppression of vacancy cluster growth in concentrated solid solution alloys

DOE PAGES

Zhao, Shijun; Velisa, Gihan; Xue, Haizhou; ...

2016-12-13

Large vacancy clusters, such as stacking-fault tetrahedra, are detrimental vacancy-type defects in ion-irradiated structural alloys. Suppression of vacancy cluster formation and growth is highly desirable to improve the irradiation tolerance of these materials. In this paper, we demonstrate that vacancy cluster growth can be inhibited in concentrated solid solution alloys by modifying cluster migration pathways and diffusion kinetics. The alloying effects of Fe and Cr on the migration of vacancy clusters in Ni concentrated alloys are investigated by molecular dynamics simulations and ion irradiation experiment. While the diffusion coefficients of small vacancy clusters in Ni-based binary and ternary solid solutionmore » alloys are higher than in pure Ni, they become lower for large clusters. This observation suggests that large clusters can easily migrate and grow to very large sizes in pure Ni. In contrast, cluster growth is suppressed in solid solution alloys owing to the limited mobility of large vacancy clusters. Finally, the differences in cluster sizes and mobilities in Ni and in solid solution alloys are consistent with the results from ion irradiation experiments.« less

One-Step Fabrication of a Multifunctional Magnetic Nickel Ferrite/Multi-walled Carbon Nanotubes Nanohybrid-Modified Electrode for the Determination of Benomyl in Food.

PubMed

Wang, Qiong; Yang, Jichun; Dong, Yuanyuan; Zhang, Lei

2015-05-20

Benomyl, as one kind of agricultural pesticide, has adverse impact on human health and the environment. It is urgent to develop effective and rapid methods for quantitative determination of benomyl. A simple and sensitive electroanalytical method for determination of benomyl using a magnetic nickel ferrite (NiFe2O4)/multi-walled carbon nanotubes (MWCNTs) nanohybrid-modified glassy carbon electrode (GCE) was presented. The electrocatalytic properties and electroanalysis of benomyl on the modified electrode were investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). In the phosphate-buffered saline (PBS) of pH 6.0, this constructed biosensor exhibited two linear relationships with the benomyl concentration range from 1.00 × 10(-7) to 5.00 × 10(-7) mol/L and from 5.00 × 10(-7) to 1.00 × 10(-5) mol/L, respectively. The detection limit was 2.51 × 10(-8) mol/L (S/N = 3). Moreover, the proposed method was successfully applied to determine benomyl in real samples with satisfactory results. The NiFe2O4/MWCNTs/GCE showed good reproducibility and stability, excellent catalytic activity, and anti-interference.

Co-digestion of ruminal content and blood from slaughterhouse industries: influence of solid concentration and ammonium generation.

PubMed

López, I; Passeggi, M; Borzacconi, L

2006-01-01

At the present time, organic solid wastes from industries and agricultural activities are considered to be promising substrates for biogas production via anaerobic digestion. Moreover solids stabilisation is required before reutilization or disposal. Slaughterhouses are among the most important industries in Uruguay and produce 150,000 tons of ruminal content (RC) and 30,000 tons of blood per year. In order to determine the influence of the solids and blood contents, the ammonia inhibition and the inoculum adaptation co-digestion batch tests were performed. A set of experiences with TS concentration of 2.5%, 5% and 7.5% and different ratios of RC/blood were carried out using an inoculum from an UASB reactor. In all experiences fast blood hydrolisation was observed. A higher methane production was detected in the experiences with higher TS content. However, the fraction of solids degradation was lower in these experiences. A plateau in the biogas production was found. The free ammonia level, which was above the reported inhibitory levels, could explain this behaviour. After the inhibition period the biogas production restarted probably due to the biomass acclimatisation to the ammonia. In order to determine the inoculum adaptation a new experiment was performed. The inoculum used was the sludge coming from the first set of experiences. Based upon batch tests a 3.5 m3 pilot reactor was designed and started up. Ammonia inhibition was avoided by the start-up strategy and in two weeks the biogas production was 3.5 m3/d. The VS stabilisation with a solid retention time of 20 days was of 43%. The pilot reactor working at steady state had a TS concentration of 3-4% with a ratio of RC/blood of 10:1 at the entrance.

Investigating nanohybrid material based on 3D CNTs@Cu nanoparticle composite and imprinted polymer for highly selective detection of chloramphenicol.

PubMed

Munawar, Anam; Tahir, Muhammad Ali; Shaheen, Ayesha; Lieberzeit, Peter A; Khan, Waheed S; Bajwa, Sadia Z

2018-01-15

Nanotechnology holds great promise for the fabrication of versatile materials that can be used as sensor platforms for the highly selective detection of analytes. In this research article we report a new nanohybrid material, where 3D imprinted nanostructures are constructed. First, copper nanoparticles are deposited on carbon nanotubes and then a hybrid structure is formed by coating molecularly imprinted polymer on 3D CNTs@Cu NPs; and a layer by layer assembly is achieved. SEM and AFM revealed the presence of Cu NPs (100-500nm) anchored along the whole length of CNTs, topped with imprinted layer. This material was applied to fabricate an electrochemical sensor to monitor a model veterinary drug, chloramphenicol. The high electron transfer ability and conductivity of the prepared material produced sensitive response, whereas, molecular imprinting produces selectivity towards drug detection. The sensor responses were found concentration dependent and the detection limit was calculated to be 10μM (S/N=3). Finally, we showed how changing the polymer composition, the extent of cross linking, and sensor layer thickness greatly affects the number of binding sites for the recognition of drug. This work paves the way to build variants of 3D imprinted materials for the detection of other kinds of biomolecules and antibiotics. Copyright © 2017 Elsevier B.V. All rights reserved.

Immediate vs delayed repair bond strength of a nanohybrid resin composite.

PubMed

El-Askary, Farid S; El-Banna, Ahmed H; van Noort, Richard

2012-06-01

To evaluate both the immediate and water-stored repair tensile bond strength (TBS) of a nanohybrid resin composite using different bonding protocols. One hundred sixty half hourglass-shaped slabs were prepared. Eighty half-slabs were wet ground immediately after light curing using high-speed abrasive burs, while the other half-slabs were stored in water for one month (delayed) and then wet ground for repair. Each set of the 80 repaired slabs was split into two groups to be tested for TBS after 24 h or 1 month of water storage. For all repaired slabs, either immediate or delayed, four bonding procedures were used involving wet and dry bonding with a 3-step etch-and-rinse adhesive with or without silane pretreatment. TBS tests were performed at a crosshead speed of 0.5 mm/min. To determine the cohesive strength of the resin composite itself, which served as the reference, additional whole slabs were prepared and tested in tension after a 24-h (n = 10) and a 1-month storage period (n = 10). Failure modes were evaluated using a stereomicroscope at 40X magnification. Three-way ANOVA was run to test the effect of water storage, testing time, bonding protocols, and their interactions on the repair TBS, which was given as a percentage of the reference values. For the immediate repair groups, the repair TBS ranged from 40% to 61.9% after 24-h storage and from 26% to 53.1% after 1-month water storage compared to the TBS of the whole slabs. For the delayed repair group, the repaired TBS ranged from 47.2% to 63.6% for the 24-h repairs and from 32.2% to 44.2% for the test groups stored in water for 1 month. Three-way ANOVA revealed that water storage had no significant effect on the repair TBS (p = 0.619). Both testing time and bonding protocols had a significant effect on the repair TBS (p = 0.001). The interactions between the independent variables (water storage, testing time, and bonding protocols) had no significant effect (p = 0.067). The repair bond strength was

Microreactor-based mixing strategy suppresses product inhibition to enhance sugar yields in enzymatic hydrolysis for cellulosic biofuel production.

PubMed

Chakraborty, Saikat; Singh, Prasun Kumar; Paramashetti, Pawan

2017-08-01

A novel microreactor-based energy-efficient process of using complete convective mixing in a macroreactor till an optimal mixing time followed by no mixing in 200-400μl microreactors enhances glucose and reducing sugar yields by upto 35% and 29%, respectively, while saving 72-90% of the energy incurred on reactor mixing in the enzymatic hydrolysis of cellulose. Empirical exponential relations are provided for determining the optimal mixing time, during which convective mixing in the macroreactor promotes mass transport of the cellulase enzyme to the solid Avicel substrate, while the latter phase of no mixing in the microreactor suppresses product inhibition by preventing the inhibitors (glucose and cellobiose) from homogenizing across the reactor. Sugar yield increases linearly with liquid to solid height ratio (r h ), irrespective of substrate loading and microreactor size, since large r h allows the inhibitors to diffuse in the liquid away from the solids, thus reducing product inhibition. Copyright © 2017 Elsevier Ltd. All rights reserved.

Combination of hTERT knockdown and interferon-γ treatment inhibited angiogenesis and tumor progression in glioblastoma

PubMed Central

George, Joseph; Banik, Naren L.; Ray, Swapan K.

2009-01-01

Purpose The limitless invasive and proliferative capacities of tumor cells are associated with telomerase and expression of its catalytic component, human telomerase reverse transcriptase (hTERT). Interferon-γ (IFN-γ) modulates several cellular activities including signaling pathways and cell cycle through transcriptional regulation. Experimental Design Using a recombinant plasmid with hTERT siRNA cDNA, we down regulated hTERT during IFN-γ treatment in human glioblastoma SNB-19 and LN-18 cell lines and examined whether such a combination could inhibit angiogenesis and tumor growth in nude mice. In vitro angiogenesis assay was performed using co-culture of tumor cells with human microvascular endothelial cells. In vivo angiogenesis assay was performed using diffusion chambers under the dorsal skin of nude mice. In vivo imaging of intracerebral tumorigenesis and longitudinal solid tumor development studies were conducted in nude mice. Results In vitro and in vivo angiogenesis assays demonstrated inhibition of capillary-like network formation of microvascular endothelial cells and neovascularization under dorsal skin of nude mice, respectively. We observed inhibition of intracerebral tumorigenesis and subcutaneous solid tumor formation in nude mice after treatment with combination of hTERT siRNA and IFN-γ. Western blotting of solid tumor samples demonstrated significant down regulation of the molecules that regulate cell invasion, angiogenesis, and tumor progression. Conclusions Our study demonstrated that combination of hTERT siRNA and IFN-γ effectively inhibited angiogenesis and tumor progression through down regulation of molecules involved in these processes. Therefore, combination of hTERT siRNA and IFN-γ is a promising therapeutic strategy for controlling growth of human glioblastoma. PMID:19934306

Production of fungal antibiotics using polymeric solid supports in solid-state and liquid fermentation.

PubMed

Bigelis, Ramunas; He, Haiyin; Yang, Hui Y; Chang, Li-Ping; Greenstein, Michael

2006-10-01

The use of inert absorbent polymeric supports for cellular attachment in solid-state fungal fermentation influenced growth, morphology, and production of bioactive secondary metabolites. Two filamentous fungi exemplified the utility of this approach to facilitate the discovery of new antimicrobial compounds. Cylindrocarpon sp. LL-Cyan426 produced pyrrocidines A and B and Acremonium sp. LL-Cyan416 produced acremonidins A-E when grown on agar bearing moist polyester-cellulose paper and generated distinctly different metabolite profiles than the conventional shaken or stationary liquid fermentations. Differences were also apparent when tenfold concentrated methanol extracts from these fermentations were tested against antibiotic-susceptible and antibiotic-resistant Gram-positive bacteria, and zones of inhibition were compared. Shaken broth cultures of Acremonium sp. or Cylindrocarpon sp. showed complex HPLC patterns, lower levels of target compounds, and high levels of unwanted compounds and medium components, while agar/solid support cultures showed significantly increased yields of pyrrocidines A and B and acremonidins A-E, respectively. This method, mixed-phase fermentation (fermentation with an inert solid support bearing liquid medium), exploited the increase in surface area available for fungal growth on the supports and the tendency of some microorganisms to adhere to solid surfaces, possibly mimicking their natural growth habits. The production of dimeric anthraquinones by Penicillium sp. LL-WF159 was investigated in liquid fermentation using various inert polymeric immobilization supports composed of polypropylene, polypropylene cellulose, polyester-cellulose, or polyurethane. This culture produced rugulosin, skyrin, flavomannin, and a new bisanthracene, WF159-A, after fermentation in the presence and absence of polymeric supports for mycelial attachment. The physical nature of the different support systems influenced culture morphology and relative

Advanced biohybrid materials based on nanoclays for biomedical applications

NASA Astrophysics Data System (ADS)

Ruiz-Hitzky, Eduardo; Darder, Margarita; Wicklein, Bernd; Fernandes, Francisco M.; Castro-Smirnov, Fidel A.; Martín del Burgo, M. Angeles; del Real, Gustavo; Aranda, Pilar

2012-10-01

Bio-nanohybrids prepared by assembling natural polymers (polysaccharides, proteins, nucleic acids, etc) to nanosized silicates (nanoclays) and related solids (layered double hydroxides, LDHs) give rise to the so-called bionanocomposites constituting a group of biomaterials with potential applications in medicine. In this way, biopolymers, including chitosan, pectin, alginate, xanthan gum, ι-carrageenan, gelatin, zein, and DNA, as well as phospholipids such as phosphatidylcholine, have been incorporated in layered host matrices by means of ion-exchange mechanisms producing intercalation composites. Also bio-nanohybrids have been prepared by the assembly of diverse bio-polymers with sepiolite, a natural microfibrous magnesium silicate, in this case through interactions affecting the external surface of this silicate. The properties and applications of these resulting biomaterials as active phases of ion-sensors and biosensors, for potential uses as scaffolds for tissue engineering, drug delivery, and gene transfection systems, are introduced and discussed in this work. It is also considered the use of synthetic bionanocomposites as new substrates to immobilize microorganisms, as for instance to bind Influenza virus particles, allowing their application as effective low-cost vaccine adjuvants and carriers.

Belief inhibition during thinking: not always winning but at least taking part.

PubMed

De Neys, Wim; Franssens, Samuel

2009-10-01

Human thinking is often biased by intuitive beliefs. Inhibition of these tempting beliefs is considered a key component of human thinking, but the process is poorly understood. In the present study we clarify the nature of an inhibition failure and the resulting belief bias by probing the accessibility of cued beliefs after people reasoned. Results indicated that even the poorest reasoners showed an impaired memory access to words that were associated with cued beliefs after solving reasoning problems in which the beliefs conflicted with normative considerations (Experiment 1 and 2). The study further established that the impairment was only temporary in nature (Experiment 3) and did not occur when people were explicitly instructed to give mere intuitive judgments (Experiment 4). Findings present solid evidence for the postulation of an inhibition process and imply that belief bias does not result from a failure to recognize the need to inhibit inappropriate beliefs, but from a failure to complete the inhibition process. This indicates that people are far more logical than hitherto believed.

Protected Lithium-Metal Anodes in Batteries: From Liquid to Solid.

PubMed

Yang, Chunpeng; Fu, Kun; Zhang, Ying; Hitz, Emily; Hu, Liangbing

2017-09-01

High-energy lithium-metal batteries are among the most promising candidates for next-generation energy storage systems. With a high specific capacity and a low reduction potential, the Li-metal anode has attracted extensive interest for decades. Dendritic Li formation, uncontrolled interfacial reactions, and huge volume effect are major hurdles to the commercial application of Li-metal anodes. Recent studies have shown that the performance and safety of Li-metal anodes can be significantly improved via organic electrolyte modification, Li-metal interface protection, Li-electrode framework design, separator coating, and so on. Superior to the liquid electrolytes, solid-state electrolytes are considered able to inhibit problematic Li dendrites and build safe solid Li-metal batteries. Inspired by the bright prospects of solid Li-metal batteries, increasing efforts have been devoted to overcoming the obstacles of solid Li-metal batteries, such as low ionic conductivity of the electrolyte and Li-electrolyte interfacial problems. Here, the approaches to protect Li-metal anodes from liquid batteries to solid-state batteries are outlined and analyzed in detail. Perspectives regarding the strategies for developing Li-metal anodes are discussed to facilitate the practical application of Li-metal batteries. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Solid- and vapor-phase antimicrobial activities of six essential oils: susceptibility of selected foodborne bacterial and fungal strains.

PubMed

López, P; Sánchez, C; Batlle, R; Nerín, C

2005-08-24

The antimicrobial activity of essential oils (EOs) of cinnamon (Cinnamon zeylanicum), clove (Syzygium aromaticum), basil (Ocimum basillicum), rosemary (Rosmarinus officinalis), dill (Anethum graveolens), and ginger (Zingiber officinalis) was evaluated over a range of concentrations in two types of contact tests (solid and vapor diffusion). The EOs were tested against an array of four Gram-positive bacteria (Staphylococcus aureus, Bacillus cereus, Enterococcus faecalis, and Listeria monocytogenes), four Gram-negative bacteria (Escherichia coli, Yersinia enterocolitica, Salmonella choleraesuis, and Pseudomonas aeruginosa), and three fungi (a yeast, Candida albicans, and two molds, Penicillium islandicum and Aspergillus flavus). The rationale for this work was to test the possibility of creating a protective atmosphere by using natural compounds that could extend the shelf life of packaged foodstuffs while minimizing organoleptic alterations. In the solid diffusion tests, cinnamon and clove gave the strongest (and very similar) inhibition, followed by basil and rosemary, with dill and ginger giving the weakest inhibition. The fungi were the most sensitive microorganisms, followed by the Gram-positive bacterial strains. The Gram-negative strain P. aeruginosa was the least inhibited. The composition of the atmosphere generated by the EOs, and their minimum inhibitory concentrations (MICs), were determined using a disk volatilization method, in which no inhibition from rosemary or basil was observed. Cinnamon and clove, once again, gave similar results for every microorganism. As a general rule, MIC (fungi) < MIC (bacteria) with no clear differences between Gram-positive or -negative strains except for P. aeruginosa, which was not inhibited by any of the EOs in the vapor phase. The atmosphere generated from the EOs was analyzed by means of solid-phase microextraction combined with gas chromatography-ion trap mass spectrometry. Differences among the volatiles in the EOs

Homogeneous synthesis of Ag nanoparticles-doped water-soluble cellulose acetate for versatile applications.

PubMed

Cao, Jie; Sun, Xunwen; Zhang, Xinxing; Lu, Canhui

2016-11-01

We report a facile and efficient approach for synthesis of well-dispersed and stable silver nanoparticles (Ag NPs) using water-soluble cellulose acetate (CA) as both reductant and stabilizer. Partially substituted CA with highly active hydroxyl groups and excellent water-solubility is able to reduce silver ions in homogeneous aqueous medium effectively. The synthesized Ag NPs were characterized by UV-vis spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy and energy dispersive X-ray spectroscope analysis. The as-prepared Ag NPs were well-dispersed, showing a surface plasmon resonance peak at 426nm. The resulted Ag NPs@CA nanohybrids exhibit high catalytic activity for the reduction of 4-nitrophenol to 4-aminophenol in the presence of NaBH 4 . Meanwhile, the nanohybrids are also effective in inhibiting the growth of bacterial. This environmentally friendly method promotes the use of renewable natural resources to prepare a variety of inorganic-organic materials for catalysis, antibacterial, sensors and other applications. Copyright © 2016 Elsevier B.V. All rights reserved.

The JAK2 Inhibitor, AZD1480, Potently Blocks Stat3 Signaling and Oncogenesis in Solid Tumors

PubMed Central

Hedvat, Michael; Huszar, Dennis; Herrmann, Andreas; Gozgit, Joseph M.; Schroeder, Anne; Sheehy, Adam; Buettner, Ralf; Proia, David; Kowolik, Claudia M.; Xin, Hong; Armstrong, Brian; Bebernitz, Geraldine; Weng, Shaobu; Wang, Lin; Ye, Minwei; McEachern, Kristen; Chen, Huawei; Morosini, Deborah; Bell, Kirsten; Alimzhanov, Marat; Ioannidis, Stephanos; McCoon, Patricia; Cao, Zhu A.; Yu, Hua; Jove, Richard; Zinda, Michael

2009-01-01

Summary Persistent activation of Stat3 is oncogenic and is prevalent in a wide variety of human cancers. Chronic cytokine stimulation is associated with Stat3 activation in some tumors, implicating cytokine receptor-associated Jak family kinases. Using Jak2 inhibitors, we demonstrate a central role of Jaks in modulating basal and cytokine-induced Stat3 activation in human solid tumor cell lines. Inhibition of Jak2 activity is associated with abrogation of Stat3 nuclear translocation and tumorigenesis. The Jak2 inhibitor, AZD1480, suppresses the growth of human solid tumor xenografts harboring persistent Stat3 activity. We demonstrate the essential role of Stat3 downstream of Jaks by inhibition of tumor growth using shRNA targeting Stat3. Our data support a key role of Jak kinase activity in Stat3-dependent tumorigenesis. PMID:19962667

Enhancement of solubility and dissolution of coenzyme Q10 using solid dispersion formulation.

PubMed

Nepal, Pushp R; Han, Hyo-Kyung; Choi, Hoo-Kyun

2010-01-04

This study aimed to develop a stable solid dispersion of Coenzyme Q(10) (CoQ(10)) with high aqueous solubility and dissolution rate. Among various carriers screened, poloxamer 407 was most effective to form a superior solid dispersion of CoQ(10) having significantly enhanced solubility. Particularly, solid dispersion of CoQ(10) with poloxamer 407 in the weight ratio of 1:5 prepared by melting method enhanced the solubility of CoQ(10) to the greatest extent. However, it exhibited poor stability and hence Aerosil 200 (colloidal silicon dioxide) was incorporated into the solid dispersion as an adsorbent to inhibit the recrystallization process. The solid dispersion of CoQ(10), poloxamer 407 and Aerosil 200 in the weight ratio of 1:5:6 exhibited improved stability with no significant change in solubility during the 1-month stability test. Moreover, the solid dispersion formulation containing Aerosil 200 significantly enhanced the extent of drug release (approx. 75% release) as well as the dissolution rate of CoQ(10). In conclusion, the present study has developed the stable solid dispersion formulation of CoQ(10) with poloxamer 407 and Aerosil 200 for the enhanced solubility and dissolution of CoQ(10), which could also offer some additional advantages including ease of preparation, good flowability and cost-effectiveness.

Integration of Flex Nozzle System and Electro Hydraulic Actuators to Solid Rocket Motors

NASA Astrophysics Data System (ADS)

Nayani, Kishore Nath; Bajaj, Dinesh Kumar

2017-10-01

A rocket motor assembly comprised of solid rocket motor and flex nozzle system. Integration of flex nozzle system and hydraulic actuators to the solid rocket motors are done after transportation to the required place where integration occurred. The flex nozzle system is integrated to the rocket motor in horizontal condition and the electro hydraulic actuators are assembled to the flex nozzle systems. The electro hydraulic actuators are connected to the hydraulic power pack to operate the actuators. The nozzle-motor critical interface are insulation diametrical compression, inhibition resin-28, insulation facial compression, shaft seal `O' ring compression and face seal `O' ring compression.

Re-fermentation of washed spent solids from batch hydrogenogenic fermentation for additional production of biohydrogen from the organic fraction of municipal solid waste.

PubMed

Muñoz-Páez, Karla M; Ríos-Leal, Elvira; Valdez-Vazquez, Idania; Rinderknecht-Seijas, Noemí; Poggi-Varaldo, Héctor M

2012-03-01

In the first batch solid substrate anaerobic hydrogenogenic fermentation with intermittent venting (SSAHF-IV) of the organic fraction of municipal solid waste (OFMSW), a cumulative production of 16.6 mmol H(2)/reactor was obtained. Releases of hydrogen partial pressure first by intermittent venting and afterward by flushing headspace of reactors with inert gas N(2) allowed for further hydrogen production in a second to fourth incubation cycle, with no new inoculum nor substrate nor inhibitor added. After the fourth cycle, no more H(2) could be harvested. Interestingly, accumulated hydrogen in 4 cycles was 100% higher than that produced in the first cycle alone. At the end of incubation, partial pressure of H(2) was near zero whereas high concentrations of organic acids and solvents remained in the spent solids. So, since approximate mass balances indicated that there was still a moderate amount of biodegradable matter in the spent solids we hypothesized that the organic metabolites imposed some kind of inhibition on further fermentation of digestates. Spent solids were washed to eliminate organic metabolites and they were used in a second SSAHF-IV. Two more cycles of H(2) production were obtained, with a cumulative production of ca. 2.4 mmol H(2)/mini-reactor. As a conclusion, washing of spent solids of a previous SSAHF-IV allowed for an increase of hydrogen production by 15% in a second run of SSAHF-IV, leading to the validation of our hypothesis. Copyright © 2011 Elsevier Ltd. All rights reserved.

Improving the performance of enzymes in hydrolysis of high solids paper pulp derived from MSW.

PubMed

Puri, Dhivya J; Heaven, Sonia; Banks, Charles J

2013-01-01

The research aimed to improve the overall conversion efficiency of the CTec® family of enzymes by identifying factors that lead to inhibition and seeking methods to overcome these through process modification and manipulation. The starting material was pulp derived from municipal solid waste and processed in an industrial-scale washing plant. Analysis of the pulp by acid hydrolysis showed a ratio of 55 : 12 : 6 : 24 : 3 of glucan : xylan : araban/galactan/mannan : lignin : ash. At high total solids content (>18.5% TS) single-stage enzyme hydrolysis gave a maximum glucan conversion of 68%. It was found that two-stage hydrolysis could give higher conversion if sugar inhibition was removed by an intermediate fermentation step between hydrolysis stages. This, however, was not as effective as direct removal of the sugar products, including xylose, by washing of the residual pulp at pH 5. This improved the water availability and allowed reactivation of the pulp-bound enzymes. Inhibition of enzyme activity could further be alleviated by replenishment of β-glucosidase which was shown to be removed during the wash step. The two-stage hydrolysis process developed could give an overall glucan conversion of 88%, with an average glucose concentration close to 8% in 4 days, thus providing an ideal starting point for ethanol fermentation with a likely yield of 4 wt%. This is a significant improvement over a single-step process. This hydrolysis configuration also provides the potential to recover the sugars associated with residual solids which are diluted when washing hydrolysed pulp.

Drop Printing of Pharmaceuticals: Effect of Molecular Weight on PEG Coated-Naproxen/PEG3350 Solid Dispersions

PubMed Central

Hsu, Hsin-Yun; Toth, Scott; Simpson, Garth J.; Harris, Michael T.

2016-01-01

Solid dispersions have been used to enhance the bioavailability of poorly water-soluble active pharmaceutical ingredients (APIs). However, the solid state phase, compositional uniformity, and scale-up problems are issues that need to be addressed. To allow for highly controllable products, the Drop Printing (DP) technique can provide precise dosages and predictable compositional uniformity of APIs in two/three dimensional structures. In this study, DP was used to prepare naproxen (NAP)/polyethylene glycol 3350 (PEG3350) solid dispersions with PEG coatings of different molecular weights (MW). A comparison of moisture-accelerated crystallization inhibition by different PEG coatings was assessed. Scanning electron microscopy (SEM), second harmonic generation (SHG) microscopy, and differential scanning calorimetry (DSC) analysis were performed to characterize the morphology and quantify the apparent crystallinity of NAP within the solid dispersions. Thermogravimetric analysis (TGA) was employed to measure the water content within each sample. The results suggest that the moisture-accelerated crystallization inhibition capability of the PEG coatings increased with increasing MW of the PEG coating. Besides, to demonstrate the flexibility of DP technology on manufacturing formulation, multilayer tablets with different PEG serving as barrier layers were also constructed, and their dissolution behavior was examined. By applying DP and appropriate materials, it is possible to design various carrier devices used to control the release dynamics of the API. PMID:27041744

Drop Printing of Pharmaceuticals: Effect of Molecular Weight on PEG Coated-Naproxen/PEG3350 Solid Dispersions.

PubMed

Hsu, Hsin-Yun; Toth, Scott; Simpson, Garth J; Harris, Michael T

2015-12-01

Solid dispersions have been used to enhance the bioavailability of poorly water-soluble active pharmaceutical ingredients (APIs). However, the solid state phase, compositional uniformity, and scale-up problems are issues that need to be addressed. To allow for highly controllable products, the Drop Printing (DP) technique can provide precise dosages and predictable compositional uniformity of APIs in two/three dimensional structures. In this study, DP was used to prepare naproxen (NAP)/polyethylene glycol 3350 (PEG3350) solid dispersions with PEG coatings of different molecular weights (MW). A comparison of moisture-accelerated crystallization inhibition by different PEG coatings was assessed. Scanning electron microscopy (SEM), second harmonic generation (SHG) microscopy, and differential scanning calorimetry (DSC) analysis were performed to characterize the morphology and quantify the apparent crystallinity of NAP within the solid dispersions. Thermogravimetric analysis (TGA) was employed to measure the water content within each sample. The results suggest that the moisture-accelerated crystallization inhibition capability of the PEG coatings increased with increasing MW of the PEG coating. Besides, to demonstrate the flexibility of DP technology on manufacturing formulation, multilayer tablets with different PEG serving as barrier layers were also constructed, and their dissolution behavior was examined. By applying DP and appropriate materials, it is possible to design various carrier devices used to control the release dynamics of the API.

Sugar loss and enzyme inhibition due to oligosaccharides accumulation during high solids-loading enzymatic hydrolysis

USDA-ARS?s Scientific Manuscript database

Oligosaccharide accumulation occurs during high solid loading enzymatic hydrolysis of corn stover (CS) irrespective of using different pretreated corn stover (dilute acid: DA, ionic liquids: IL, ammonia fiber expansion: AFEX and extractive ammonia: EA). The methodology for large-scale separation of ...

Iridium Oxide-reduced Graphene Oxide Nanohybrid Thin Film Modified Screen-printed Electrodes as Disposable Electrochemical Paper Microfluidic pH Sensors.

PubMed

Yang, Jiang; Kwak, Tae-Joon; Zhang, Xiaodong; McClain, Robert; Chang, Woo-Jin; Gunasekaran, Sundaram

2016-11-22

A facile, controllable, inexpensive and green electrochemical synthesis of IrO2-graphene nanohybrid thin films is developed to fabricate an easy-to-use integrated paper microfluidic electrochemical pH sensor for resource-limited settings. Taking advantages from both pH meters and strips, the pH sensing platform is composed of hydrophobic barrier-patterned paper micropad (µPAD) using polydimethylsiloxane (PDMS), screen-printed electrode (SPE) modified with IrO2-graphene films and molded acrylonitrile butadiene styrene (ABS) plastic holder. Repetitive cathodic potential cycling was employed for graphene oxide (GO) reduction which can completely remove electrochemically unstable oxygenated groups and generate a 2D defect-free homogeneous graphene thin film with excellent stability and electronic properties. A uniform and smooth IrO2 film in nanoscale grain size is anodically electrodeposited onto the graphene film, without any observable cracks. The resulting IrO2-RGO electrode showed slightly super-Nernstian responses from pH 2-12 in Britton-Robinson (B-R) buffers with good linearity, small hysteresis, low response time and reproducibility in different buffers, as well as low sensitivities to different interfering ionic species and dissolved oxygen. A simple portable digital pH meter is fabricated, whose signal is measured with a multimeter, using high input-impedance operational amplifier and consumer batteries. The pH values measured with the portable electrochemical paper-microfluidic pH sensors were consistent with those measured using a commercial laboratory pH meter with a glass electrode.

Inhibiting surface crystallization of amorphous indomethacin by nanocoating.

PubMed

Wu, Tian; Sun, Ye; Li, Ning; de Villiers, Melgardt M; Yu, Lian

2007-04-24

An amorphous solid (glass) may crystallize faster at the surface than through the bulk, making surface crystallization a mechanism of failure for amorphous pharmaceuticals and other materials. An ultrathin coating of gold or polyelectrolytes inhibited the surface crystallization of amorphous indomethacin (IMC), an anti-inflammatory drug and model organic glass. The gold coating (10 nm) was deposited by sputtering, and the polyelectrolyte coating (3-20 nm) was deposited by an electrostatic layer-by-layer assembly of cationic poly(dimethyldiallyl ammonium chloride) (PDDA) and anionic sodium poly(styrenesulfonate) (PSS) in aqueous solution. The coating also inhibited the growth of existing crystals. The inhibition was strong even with one layer of PDDA. The polyelectrolyte coating still permitted fast dissolution of amorphous IMC and improved its wetting and flow. The finding supports the view that the surface crystallization of amorphous IMC is enabled by the mobility of a thin layer of surface molecules, and this mobility can be suppressed by a coating of only a few nanometers. This technique may be used to stabilize amorphous drugs prone to surface crystallization, with the aqueous coating process especially suitable for drugs of low aqueous solubility.

Poly(allyl methacrylate) functionalized hydroxyapatite nanocrystals via the combination of surface-initiated RAFT polymerization and thiol-ene protocol: a potential anticancer drug nanocarrier.

PubMed

Bach, Long Giang; Islam, Md Rafiqul; Vo, Thanh-Sang; Kim, Se-Kwon; Lim, Kwon Taek

2013-03-15

Hydroxyapatite nanocrystals (HAP NCs) were encapsulated by poly(allyl methacrylate) (PolyAMA) employing controlled surface-initiated reversible addition-fragmentation chain transfer (SI-RAFT) polymerization of allyl methacrylate to afford HAP-PolyAMA nanohybrids. The subsequent thiol-ene coupling of nanohybrids with 2-mercaptosuccinic acid resulted HAP-Poly(AMA-COOH) possessing multicarboxyl group. The formation of the nanohybrids was confirmed by FT-IR and EDS analyses. The TGA and FE-SEM investigation were further suggested the grafting of PolyAMA onto HAP NCs. The utility of the HAP-PolyAMA nanohybrid as drug carrier was also explored. The pendant carboxyl groups on the external layers of nanohybrids were conjugated with anticancer drug cisplatin to afford HAP-Poly(AMA-COOH)/Pt complex. The formation of the complex was confirmed by FT-IR, XPS, and FE-SEM. In vitro evaluation of the synthesized complex as nanomedicine revealed its potential chemotherapeutic efficacy against cancer cell lines. Copyright © 2012 Elsevier Inc. All rights reserved.

Novel tablet formulation of amorphous candesartan cilexetil solid dispersions involving P-gp inhibition for optimal drug delivery: in vitro and in vivo evaluation.

PubMed

Surampalli, Gurunath; Nanjwade, Basavaraj K; Patil, P A; Chilla, Rakesh

2016-09-01

The aim of this study was to develop a novel tablet formulation of amorphous candesartan cilexetil (CAN) solid dispersion involving effective P-gp inhibition for optimal drug delivery by direct compression (DC) method. To accomplish DC, formulation blends were evaluated for micromeritic properties. The Carr index, Hausner ratio, flow rate and cotangent of the angle α were determined. The tablets with and without naringin prepared by DC technique were evaluated for average weight, hardness, disintegration time and friability assessments. The drug release profiles were determined to study the dissolution kinetics. In vivo pharmacokinetic studies were conducted in rabbits. Accelerated stability studies were performed for tablets at 40 ± 2 °C/75% RH ± 5% for 6 months. FTIR studies confirmed no discoloration, liquefaction and physical interaction between naringin and drug. The results indicated that tablets prepared from naringin presented a dramatic release (82%) in 30 min with a similarity factor (76.18), which is most likely due to the amorphous nature of drug and the higher micromeritic properties of blends. Our findings noticed 1.7-fold increase in oral bioavailability of tablet prepared from naringin with mean C max and AUC 0-12 h values as 35.81 ± 0.13 μg/mL and 0.14 ± 0.09 μg h/mL, respectively. The tablets with and without naringin prepared by DC technique were physically and chemically stable under accelerated stability conditions upon storage for 6 months. These results are attractive for further development of an oral tablet formulation of CAN through P-gp inhibition using naringin, a natural flavonoid as a pharmaceutical excipient.

Solid-phase receptor binding assay for /sup 125/I-hCG

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bortolussi, M.; Selmin, O.; Colombatti, A.

1987-01-01

A solid-phase radioligand-receptor assay (RRA) to measure the binding of /sup 125/I-labelled human chorionic gonadotropin (/sup 125/I-hCG) to target cell membranes has been developed. The binding of /sup 125/I-hCG to membranes immobilized on the wells of microtitration plates reached a maximum at about 3 hours at 37 degrees C, was saturable, displayed a high affinity (Ka = 2.4 X 10(9) M-1) and was specifically inhibited by unlabelled hCG. In comparison with RRAs carried out with membranes in suspension, the solid-phase RRA is significantly simpler and much faster to perform as it avoids centrifugation or filtration procedures. The solid-phase RRA wasmore » adapted profitably to process large numbers of samples at the same time. It proved particularly useful as a screening assay to detect anti-hCG monoclonal antibodies with high inhibitory activity for binding of /sup 125/I-hCG to its receptors.« less

Solid state anaerobic co-digestion of tomato residues with dairy manure and corn stover for biogas production.

PubMed

Li, Yangyang; Li, Yu; Zhang, Difang; Li, Guoxue; Lu, Jiaxin; Li, Shuyan

2016-10-01

Solid-state anaerobic co-digestion of tomato residues with dairy manure and corn stover was conducted at 20% total solids under 35°C for 45days. Results showed digestion of mixed tomato residues with dairy manure and corn stover improved methane yields. The highest VS reduction (46.2%) and methane yield (415.4L/kg VSfeed) were achieved with the ternary mixtures of 33% corn stover, 54% dairy manure, and 13% tomato residues, lead to a 0.5-10.2-fold higher than that of individual feedstocks. Inhibition of volatile fatty acids (VFAs) to biogas production occurred when more than 40% tomato residues were added. The results indicated that ternary mixtures diluted the inhibitors that would otherwise cause inhibition in the digestion of tomato residues as a mono-feedstock. Copyright © 2016. Published by Elsevier Ltd.

Nanostructured lipid carriers: effect of solid phase fraction and distribution on the release of encapsulated materials.

PubMed

Dan, Nily

2014-11-25

Emulsions, solid lipid nanoparticles (SLN), and nanostructured lipid carriers (NLC) containing a mix of liquid and solid domains are of interest as encapsulation vehicles for hydrophobic compounds. Studies of the release rate from these particles yield contradictory results: Some find that increasing the fraction of solid phase increases the rate of release and others the opposite. In this paper we study the release of encapsulated materials from lipid-based nanoparticles using Monte Carlo simulations. We find that, quite surprisingly, the release rate is largely insensitive to the size of solid domains or the fraction of solid phase. However, the distribution of the domains significantly affects the rate of release: Solid domains located at the interface with the surrounding solution inhibit transport, while nanoparticles where the solid domains are concentrated in the center enhance it. The latter can lead to release rates in NLCs that are faster than in the equivalent emulsions. We conclude that controlling the release rate from NLCs requires the ability to determine the location and distribution of the solid phase, which may be achieved through choice of the surfactants stabilizing the particles, incorporation of nucleation sites, and/or the cooling rates and temperatures.

Pineapple juice and its fractions in enzymatic browning inhibition of banana [Musa (AAA group) Gros Michel].

PubMed

Chaisakdanugull, Chitsuda; Theerakulkait, Chockchai; Wrolstad, Ronald E

2007-05-16

The effectiveness of pineapple juice in enzymatic browning inhibition was evaluated on the cut surface of banana slices. After storage of banana slices at 15 degrees C for 3 days, pineapple juice showed browning inhibition to a similar extent as 8 mM ascorbic acid but less than 4 mM sodium metabisulfite. Fractionation of pineapple juice by a solid-phase C18 cartridge revealed that the directly eluted fraction (DE fraction) inhibited banana polyphenol oxidase (PPO) about 100% when compared to the control. The DE fraction also showed more inhibitory effect than 8 mM ascorbic acid in enzymatic browning inhibition of banana puree during storage at 5 degrees C for 24 h. Further identification of the DE fraction by fractionation with ion exchange chromatography and confirmation using model systems indicated that malic acid and citric acid play an important role in the enzymatic browning inhibition of banana PPO.

C-106 High-Level Waste Solids: Washing/Leaching and Solubility Versus Temperature Studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

GJ Lumetta; DJ Bates; PK Berry

This report describes the results of a test conducted by Battelle to assess the effects of inhibited water washing and caustic leaching on the composition of the Hanford tank C-106 high-level waste (HLW) solids. The objective of this work was to determine the composition of the C-106 solids remaining after washing with 0.01M NaOH or leaching with 3M NaOH. Another objective of this test was to determine the solubility of various C-106 components as a function of temperature. The work was conducted according to test plan BNFL-TP-29953-8,Rev. 0, Determination of the Solubility of HLW Sludge Solids. The test went accordingmore » to plan, with only minor deviations from the test plan. The deviations from the test plan are discussed in the experimental section.« less

An improved kinetics approach to describe the physical stability of amorphous solid dispersions.

PubMed

Yang, Jiao; Grey, Kristin; Doney, John

2010-01-15

The recrystallization of amorphous solid dispersions may lead to a loss in the dissolution rate, and consequently reduce bioavailability. The purpose of this work is to understand factors governing the recrystallization of amorphous drug-polymer solid dispersions, and develop a kinetics model capable of accurately predicting their physical stability. Recrystallization kinetics was measured using differential scanning calorimetry for initially amorphous efavirenz-polyvinylpyrrolidone solid dispersions stored at controlled temperature and relative humidity. The experimental measurements were fitted by a new kinetic model to estimate the recrystallization rate constant and microscopic geometry of crystal growth. The new kinetics model was used to illustrate the governing factors of amorphous solid dispersions stability. Temperature was found to affect efavirenz recrystallization in an Arrhenius manner, while recrystallization rate constant was shown to increase linearly with relative humidity. Polymer content tremendously inhibited the recrystallization process by increasing the crystallization activation energy and decreasing the equilibrium crystallinity. The new kinetic model was validated by the good agreement between model fits and experiment measurements. A small increase in polyvinylpyrrolidone resulted in substantial stability enhancements of efavirenz amorphous solid dispersion. The new established kinetics model provided more accurate predictions than the Avrami equation.

Preparation and characterization of azithromycin--Aerosil 200 solid dispersions with enhanced physical stability.

PubMed

Li, Xuechao; Peng, Huanhuan; Tian, Bin; Gou, Jingxin; Yao, Qing; Tao, Xiaoguang; He, Haibing; Zhang, Yu; Tang, Xing; Cai, Cuifang

2015-01-01

The main purpose of this study was to investigate the feasibility of azithromycin (AZI)--Aerosil 200 solid dispersions specifically with high stability under accelerated condition (40 °C/75% RH). Ball milling (BM) and hot-melt extrusion (HME) were used to prepare AZI solid dispersions. The physical properties of solid dispersions were evaluated by differential scanning calorimetry (DSC), scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA). For solid dispersions prepared with both methods, no crystalline of AZI was detected (except for AZI: Aerosil 200=75:25) by DSC or PXRD, indicating the amorphous state of AZI in solid dispersions. The FT-IR results demonstrated the loss of crystallization water and the formation of hydrogen bonds between Aerosil 200 and AZI during the preparation of solid dispersions. After 4 weeks storage under accelerated condition, the degree of crystallinity of AZI increased in solid dispersions prepared by BM, whereas for solid dispersions containing AZI, Aerosil 200 and glyceryl behenate (GB) prepared by HME, no crystalline of AZI was identified. This high stability can be attributed to the hydrophobic properties of GB and the presence of hydrogen bonds. Based on the above results, it is inferred the protection of hydrogen bonds between AZI and Aerosil 200 formed during preparation process effectively inhibited the recrystallization of AZI and improved the physical stability of amorphous AZI in the presence of Aerosil 200. Copyright © 2015 Elsevier B.V. All rights reserved.

Antiangiogenic and Antitumor Effects of Src Inhibition in Ovarian Carcinoma

PubMed Central

Han, Liz Y.; Landen, Charles N.; Trevino, Jose G.; Halder, Jyotsnabaran; Lin, Yvonne G.; Kamat, Aparna A.; Kim, Tae-Jin; Merritt, William M.; Coleman, Robert L.; Gershenson, David M.; Shakespeare, William C.; Wang, Yihan; Sundaramoorth, Raji; Metcalf, Chester A.; Dalgarno, David C.; Sawyer, Tomi K.; Gallick, Gary E.; Sood, Anil K.

2011-01-01

Src, a nonreceptor tyrosine kinase, is a key mediator for multiple signaling pathways that regulate critical cellular functions and is often aberrantly activated in a number of solid tumors, including ovarian carcinoma. The purpose of this study was to determine the role of activated Src inhibition on tumor growth in an orthotopic murine model of ovarian carcinoma. In vitro studies on HeyA8 and SKOV3ip1 cell lines revealed that Src inhibition by the Src-selective inhibitor, AP23846, occurred within 1 hour and responded in a dose-dependent manner. Furthermore, Src inhibition enhanced the cytotoxicity of docetaxel in both chemosensitive and chemoresistant ovarian cancer cell lines, HeyA8 and HeyA8-MDR, respectively. In vivo, Src inhibition by AP23994, an orally bioavailable analogue of AP23846, significantly decreased tumor burden in HeyA8 (P = 0.02), SKOV3ip1 (P = 0.01), as well as HeyA8-MDR (P < 0.03) relative to the untreated controls. However, the greatest effect on tumor reduction was observed in combination therapy with docetaxel (P < 0.001, P = 0.002, and P = 0.01, for the above models, respectively). Proliferating cell nuclear antigen staining showed that Src inhibition alone (P = 0.02) and in combination with docetaxel (P = 0.007) significantly reduced tumor proliferation. In addition, Src inhibition alone and in combination with docetaxel significantly down-regulated tumoral production of vascular endothelial growth factor and interleukin 8, whereas combination therapy decreased the microvessel density (P = 0.02) and significantly affected vascular permeability (P < 0.05). In summary, Src inhibition with AP23994 has potent antiangiogenic effects and significantly reduces tumor burden in preclinical ovarian cancer models. Thus, Src inhibition may be an attractive therapeutic approach for patients with ovarian carcinoma. PMID:16951177

Inhibition of Listeria monocytogenes by Food-Borne Yeasts†

PubMed Central

Goerges, Stefanie; Aigner, Ulrike; Silakowski, Barbara; Scherer, Siegfried

2006-01-01

Many bacteria are known to inhibit food pathogens, such as Listeria monocytogenes, by secreting a variety of bactericidal and bacteriostatic substances. In sharp contrast, it is unknown whether yeast has an inhibitory potential for the growth of pathogenic bacteria in food. A total of 404 yeasts were screened for inhibitory activity against five Listeria monocytogenes strains. Three hundred and four of these yeasts were isolated from smear-ripened cheeses. Most of the yeasts were identified by Fourier transform infrared spectroscopy. Using an agar-membrane screening assay, a fraction of approximately 4% of the 304 red smear cheese isolates clearly inhibited growth of L. monocytogenes. Furthermore, 14 out of these 304 cheese yeasts were cocultivated with L. monocytogenes WSLC 1364 on solid medium to test the antilisterial activity of yeast in direct cell contact with Listeria. All yeasts inhibited L. monocytogenes to a low degree, which is most probably due to competition for nutrients. However, one Candida intermedia strain was able to reduce the listerial cell count by 4 log units. Another four yeasts, assigned to C. intermedia (three strains) and Kluyveromyces marxianus (one strain), repressed growth of L. monocytogenes by 3 log units. Inhibition of L. monocytogenes was clearly pronounced in the cocultivation assay, which simulates the conditions and contamination rates present on smear cheese surfaces. We found no evidence that the unknown inhibitory molecule is able to diffuse through soft agar. PMID:16391059

Taurine zinc solid dispersions attenuate doxorubicin-induced hepatotoxicity and cardiotoxicity in rats

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Yu; Mei, Xueting; Yuan, Jingquan

2015-11-15

The clinical efficacy of anthracycline anti-neoplastic agents is limited by cardiac and hepatic toxicities. The aim of this study was to assess the hepatoprotective and cardioprotective effects of taurine zinc solid dispersions, which is a newly-synthesized taurine zinc compound, against doxorubicin-induced toxicity in Sprague–Dawley rats intraperitoneally injected with doxorubicin hydrochloride (3 mg/kg) three times a week (seven injections) over 28 days. Hemodynamic parameters, levels of liver toxicity markers and oxidative stress were assessed. Taurine zinc significantly attenuated the reductions in blood pressure, left ventricular pressure and ± dp/dtmax, increases in serum alanine aminotransferase and aspartate aminotransferase activities, and reductions inmore » serum Zn{sup 2+} and albumin levels (P < 0.05 or 0.01) induced by doxorubicin. In rats treated with doxorubicin, taurine zinc dose-dependently increased liver superoxide dismutase activity and glutathione concentration, and decreased malondialdehyde level (P < 0.01). qBase{sup +} was used to evaluate the stability of eight candidate reference genes for real-time quantitative reverse-transcription PCR. Taurine zinc dose-dependently increased liver heme oxygenase-1 and UDP-glucuronyl transferase mRNA and protein expression (P < 0.01). Western blotting demonstrated that taurine zinc inhibited c-Jun N-terminal kinase phosphorylation by upregulating dual-specificity phosphoprotein phosphatase-1. Additionally, taurine zinc inhibited cardiomyocyte apoptosis as there was decreased TUNEL/DAPI positivity and protein expression of caspase-3. These results indicate that taurine zinc solid dispersions prevent the side-effects of anthracycline-based anticancer therapy. The mechanisms might be associated with the enhancement of antioxidant defense system partly through activating transcription to synthesize endogenous phase II medicine enzymes and anti-apoptosis through inhibiting JNK phosphorylation

Graphene-oxide stabilization in electrolyte solutions using hydroxyethyl cellulose for drug delivery application.

PubMed

Mianehrow, Hanieh; Moghadam, Mohamad Hasan Mohamadzadeh; Sharif, Farhad; Mazinani, Saeedeh

2015-04-30

Stabilization of graphene oxide (GO) in physiological solution is performed using hydroxyethyl cellulose (HEC) to make the resultant nanohybrid suitable for targeted drug delivery purposes. Short and long term stability of GO suspensions with different ionic strengths were assessed using ultraviolet-visible spectroscopy (UV-vis), atomic force microscopy (AFM) and zeta potential measurements. Results depicted that HEC effectively stabilized GO in electrolyte solutions and the mechanism of stabilization appeares to be depended on HEC content. Drug loading and release behavior of folic acid (FA) as a model drug, from GO-HEC nanohybrid were studied to assess its application in drug delivery systems. Results showed the nanohybrid could be highly loaded by folic acid. Moreover, HEC content in the nanohybrid played an important role in final application to make it applicable either as a carrier for controllable drug release or as a folate-targeted drug carrier. In addition, according to cytotoxicity results, the nanohybrid showed good biocompatibility which indeed confirms its potential application as a drug carrier. Copyright © 2015 Elsevier B.V. All rights reserved.

Heme Oxygenase Inhibition Sensitizes Neuroblastoma Cells to Carfilzomib.

PubMed

Barbagallo, Ignazio; Giallongo, Cesarina; Volti, Giovanni Li; Distefano, Alfio; Camiolo, Giuseppina; Raffaele, Marco; Salerno, Loredana; Pittalà, Valeria; Sorrenti, Valeria; Avola, Roberto; Di Rosa, Michelino; Vanella, Luca; Di Raimondo, Francesco; Tibullo, Daniele

2018-06-10

Neuroblastoma (NB) is an embryonic malignancy affecting the physiological development of adrenal medulla and paravertebral sympathetic ganglia in early infancy. Proteasome inhibitors (PIs) (i.e., carfilzomib (CFZ)) may represent a possible pharmacological treatment for solid tumors including NB. In the present study, we tested the effect of a novel non-competitive inhibitor of heme oxygenase-1 (HO-1), LS1/71, as a possible adjuvant therapy for the efficacy of CFZ in neuroblastoma cells. Our results showed that CFZ increased both HO-1 gene expression (about 18-fold) and HO activity (about 8-fold), following activation of the ER stress pathway. The involvement of HO-1 in CFZ-mediated cytotoxicity was further confirmed by the protective effect of pharmacological induction of HO-1, significantly attenuating cytotoxicity. In addition, HO-1 selective inhibition by a specific siRNA increased the cytotoxic effect following CFZ treatment in NB whereas SnMP, a competitive pharmacological inhibitor of HO, showed no changes in cytotoxicity. Our data suggest that treatment with CFZ produces ER stress in NB without activation of CHOP-mediated apoptosis, whereas co-treatment with CFZ and LS1/71 led to apoptosis activation and CHOP expression induction. In conclusion, our study showed that treatment with the non-competitive inhibitor of HO-1, LS1 / 71, increased cytotoxicity mediated by CFZ, triggering apoptosis following ER stress activation. These results suggest that PIs may represent a possible pharmacological treatment for solid tumors and that HO-1 inhibition may represent a possible strategy to overcome chemoresistance and increase the efficacy of chemotherapic regimens.

Comparison of high-solids to liquid anaerobic co-digestion of food waste and green waste.

PubMed

Chen, Xiang; Yan, Wei; Sheng, Kuichuan; Sanati, Mehri

2014-02-01

Co-digestion of food waste and green waste was conducted with six feedstock mixing ratios to evaluate biogas production. Increasing the food waste percentage in the feedstock resulted in an increased methane yield, while shorter retention time was achieved by increasing the green waste percentage. Food waste/green waste ratio of 40:60 was determined as preferred ratio for optimal biogas production. About 90% of methane yield was obtained after 24.5 days of digestion, with total methane yield of 272.1 mL/g VS. Based the preferred ratio, effect of total solids (TS) content on co-digestion of food waste and green waste was evaluated over a TS range of 5-25%. Results showed that methane yields from high-solids anaerobic digestion (15-20% TS) were higher than the output of liquid anaerobic digestion (5-10% TS), while methanogenesis was inhibited by further increasing the TS content to 25%. The inhibition may be caused by organic overloading and excess ammonia. Copyright © 2013 Elsevier Ltd. All rights reserved.

An Advanced Semimetal-Organic Bi Spheres-g-C3N4 Nanohybrid with SPR-Enhanced Visible-Light Photocatalytic Performance for NO Purification.

PubMed

Dong, Fan; Zhao, Zaiwang; Sun, Yanjuan; Zhang, Yuxin; Yan, Shuai; Wu, Zhongbiao

2015-10-20

To achieve efficient photocatalytic air purification, we constructed an advanced semimetal-organic Bi spheres-g-C3N4 nanohybrid through the in-situ growth of Bi nanospheres on g-C3N4 nanosheets. This Bi-g-C3N4 compound exhibited an exceptionally high and stable visible-light photocatalytic performance for NO removal due to the surface plasmon resonance (SPR) endowed by Bi metal. The SPR property of Bi could conspicuously enhance the visible-light harvesting and the charge separation. The electromagnetic field distribution of Bi spheres involving SPR effect was simulated and reaches its maximum in close proximity to the Bi particle surface. When the Bi metal content was controlled at 25%, the corresponding Bi-g-C3N4 displayed outstanding photocatalytic capability and transcended those of other visible-light photocatalysts. The Bi-g-C3N4 exhibited a high structural stability under repeated photocatalytic runs. A new visible-light-induced SPR-based photocatalysis mechanism with Bi-g-C3N4 was proposed on the basis of the DMPO-ESR spin-trapping. The photoinduced electrons could transfer from g-C3N4 to the Bi metal, as revealed with time-resolved fluorescence spectra. The function of Bi semimetal as a plasmonic cocatalyst for boosting visible light photocatalysis was similar to that of noble metals, which demonstrated a great potential of utilizing the economically feasible Bi element as a substitute for noble metals for the advancement of photocatalysis efficiency.

Inhibition and deactivation effects in catalytic wet oxidation of high-strength alcohol-distillery liquors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Belkacemi, K.; Larachi, F.; Hamoudi, S.

1999-06-01

The removal efficiency of total organic carbon (TOC) from raw high-strength alcohol-distillery waste liquors was evaluated using three different treatments: thermolysis (T), noncatalytic wet oxidation (WO), and solid-catalyzed wet oxidation (CWO). The distillery liquors (TOC = 22,500 mg/l, sugars = 18,000 mg/l, and proteins = 13,500 mg/l) were produced by alcoholic fermentation of enzymatic hydrolyzates from steam-exploded timothy grass. TOC-abatement studies were conducted batchwise in a stirred autoclave to evaluate the influence of the catalyst (7:3, MnO{sub 2}/CeO{sub 2} mixed oxide), oxygen partial pressure (0.5--2.5 MPa), and temperature (453--523 K) on T, WO, and CWO processes. Although CWO outperformed Tmore » and WO, TOC conversions did not exceed {approximately}60% at the highest temperature used. Experiments provided prima facie evidence for a gradual fouling of the catalyst and a developing inhibition in the liquors which impaired deep TOC removals. Occurrence of catalyst deactivation by carbonaceous deposits was proven experimentally through quantitative and qualitative experiments such as elemental analysis and X-ray photoelectron spectroscopy. Inhibition toward further degradation of the liquors was ascribed to the occurrence of highly stable antioxidant intermediates via the Maillard reactions between dissolved sugars and proteins. A lumping kinetic model involving both reaction inhibition by dissolved intermediates and catalyst deactivation by carbonaceous deposits was proposed to account for the distribution of carbon in the liquid, solid, and the vapor phases.« less

Angiotensin inhibition enhances drug delivery and potentiates chemotherapy by decompressing tumour blood vessels

PubMed Central

Chauhan, Vikash P.; Martin, John D.; Liu, Hao; Lacorre, Delphine A.; Jain, Saloni R.; Kozin, Sergey V.; Stylianopoulos, Triantafyllos; Mousa, Ahmed S.; Han, Xiaoxing; Adstamongkonkul, Pichet; Popović, Zoran; Huang, Peigen; Bawendi, Moungi G.; Boucher, Yves; Jain, Rakesh K.

2013-01-01

Cancer and stromal cells actively exert physical forces (solid stress) to compress tumour blood vessels, thus reducing vascular perfusion. Tumour interstitial matrix also contributes to solid stress, with hyaluronan implicated as the primary matrix molecule responsible for vessel compression because of its swelling behaviour. Here we show, unexpectedly, that hyaluronan compresses vessels only in collagen-rich tumours, suggesting that collagen and hyaluronan together are critical targets for decompressing tumour vessels. We demonstrate that the angiotensin inhibitor losartan reduces stromal collagen and hyaluronan production, associated with decreased expression of profibrotic signals TGF-β1, CCN2 and ET-1, downstream of angiotensin-II-receptor-1 inhibition. Consequently, losartan reduces solid stress in tumours resulting in increased vascular perfusion. Through this physical mechanism, losartan improves drug and oxygen delivery to tumours, thereby potentiating chemotherapy and reducing hypoxia in breast and pancreatic cancer models. Thus, angiotensin inhibitors —inexpensive drugs with decades of safe use — could be rapidly repurposed as cancer therapeutics. PMID:24084631

Seasonal variation in Hibiscus sabdariffa (Roselle) calyx phytochemical profile, soluble solids and α-glucosidase inhibition.

PubMed

Ifie, Idolo; Ifie, Beatrice E; Ibitoye, Dorcas O; Marshall, Lisa J; Williamson, Gary

2018-09-30

Seasonal variations in crops can alter the profile and amount of constituent compounds and consequentially any biological activity. Differences in phytochemical profile, total phenolic content and inhibitory activity on α-glucosidase (maltase) of Hibiscus sabdariffa calyces grown in South Western Nigeria were determined over wet and dry seasons. The phenolic profile, organic acids and sugars were analysed using HPLC, while inhibition of rat intestinal maltase was measured enzymically. There was a significant increase (1.4-fold; p ≤ 0.05) in total anthocyanin content in the dry compared to wet planting seasons, and maltase inhibition from the dry season was slightly more potent (1.15-fold, p ≤ 0.05). Fructose (1.8-fold), glucose (1.8-fold) and malic acid (3.7-fold) were significantly higher (p ≤ 0.05) but citric acid was lower (62-fold, p ≤ 0.008) in the dry season. Environmental conditions provoke metabolic responses in Hibiscus sabdariffa affecting constituent phytochemicals and nutritional value. Copyright © 2018 Elsevier Ltd. All rights reserved.

Role of Au(NPs) in the enhanced response of Au(NPs)-decorated MWCNT electrochemical biosensor

PubMed Central

Mehmood, Shahid; Ciancio, Regina; Carlino, Elvio; Bhatti, Arshad S

2018-01-01

Background The combination of Au-metallic-NPs and CNTs are a new class of hybrid nanomaterials for the development of electrochemical biosensor. Concentration of Au(nanoparticles [NPs]) in the electrochemical biosensor is crucial for the efficient charge transfer between the Au-NPs-MWCNTs modified electrode and electrolytic solution. Methods In this work, the charge transfer kinetics in the glassy carbon electrode (GCE) modified with Au(NPs)–multiwalled carbon nanotube (MWCNT) nanohybrid with varied concentrations of Au(NPs) in the range 40–100 nM was studied using electrochemical impedance spectroscopy (EIS). Field emission scanning electron microscopy and transmission electron microscopy confirmed the attachment of Au(NPs) on the surface of MWCNTs. Results The cyclic voltammetry and EIS results showed that the charge transfer mechanism was diffusion controlled and the rate of charge transfer was dependent on the concentration of Au(NPs) in the nanohybrid. The formation of spherical diffusion zone, which was dependent on the concentration of Au(NPs) in nanohybrids, was attributed to result in 3 times the increase in the charge transfer rate ks, 5 times increase in mass transfer, and 5% (9%) increase in Ipa (Ipc) observed in cyclic voltammetry in 80 nM Au(NP) nanohybrid-modified GCE from MWCNT-modified GCE. The work was extended to probe the effect of charge transfer rates at various concentrations of Au(NPs) in the nanohybrid-modified electrodes in the presence of Escherichia coli. The cyclic voltammetry results clearly showed the best results for 80 nM Au(NPs) in nanohybrid electrode. Conclusion The present study suggested that the formation of spherical diffusion zone in nanohybrid-modified electrodes is critical for the enhanced electrochemical biosensing applications. PMID:29713161

Ethanol and anaerobic conditions reversibly inhibit commercial cellulase activity in thermophilic simultaneous saccharification and fermentation (tSSF)

PubMed Central

2012-01-01

Background A previously developed mathematical model of low solids thermophilic simultaneous saccharification and fermentation (tSSF) with Avicel was unable to predict performance at high solids using a commercial cellulase preparation (Spezyme CP) and the high ethanol yield Thermoanaerobacterium saccharolyticum strain ALK2. The observed hydrolysis proceeded more slowly than predicted at solids concentrations greater than 50 g/L Avicel. Factors responsible for this inaccuracy were investigated in this study. Results Ethanol dramatically reduced cellulase activity in tSSF. At an Avicel concentration of 20 g/L, the addition of ethanol decreased conversion at 96 hours, from 75% in the absence of added ethanol down to 32% with the addition of 34 g/L initial ethanol. This decrease is much greater than expected based on hydrolysis inhibition results in the absence of a fermenting organism. The enhanced effects of ethanol were attributed to the reduced, anaerobic conditions of tSSF, which were shown to inhibit cellulase activity relative to hydrolysis under aerobic conditions. Cellulose hydrolysis in anaerobic conditions was roughly 30% slower than in the presence of air. However, this anaerobic inhibition was reversed by exposing the cellulase enzymes to air. Conclusion This work demonstrates a previously unrecognized incompatibility of enzymes secreted by an aerobic fungus with the fermentation conditions of an anaerobic bacterium and suggests that enzymes better suited to industrially relevant fermentation conditions would be valuable. The effects observed may be due to inactivation or starvation of oxygen dependent GH61 activity, and manipulation or replacement of this activity may provide an opportunity to improve biomass to fuel process efficiency. PMID:22703989

Ferrocenylaniline based amide analogs of methoxybenzoic acids: Synthesis, structural characterization and butyrylcholinesterase (BChE) inhibition studies

NASA Astrophysics Data System (ADS)

Altaf, Ataf Ali; Kausar, Samia; Hamayun, Muhammad; Lal, Bhajan; Tahir, Muhammad Nawaz; Badshah, Amin

2017-10-01

Three new ferrocene based amides were synthesized with slight structural difference. The general formula of the amides is C5H5FeC5H4C6H4NHCOC6H4(OCH3). The synthesized compounds were characterized by instrumental techniques like elemental analysis, FTIR and NMR spectroscopy. Structure of the two compounds was also studied by single crystal X-rays diffraction analysis. Structural studies provide the evidence that pMeO (one of the synthesized compounds) is an example of amides having no intermolecular hydrogen bonding in solid structure. In the BChE inhibition assay, compound (oMeO) having strong intermolecular force in the solid structure is less active than the compound (pMeO) with weak intermolecular forces in the solid structure. The docking studies proved that hydrogen bonding between inhibitor and BChE enzyme is of more importance for the activity, rather than intermolecular hydrogen bonding in the solid structure of inhibitor.

Synthesis and characterization of Ag2S decorated chitosan nanocomposites and chitosan nanofibers for removal of lincosamides antibiotic.

PubMed

Gupta, Vinod Kumar; Fakhri, Ali; Agarwal, Shilpi; Azad, Mona

2017-10-01

We report the synthesis of Ag 2 S-Chitosan nanocomposites and Ag 2 S-chitosan nanohybrids as performance adsorbents for Lincosamides such as Clindamycin antibiotic removal. Isotherms and kinetic studies were determined to understand the adsorption behavior both two adsorbent. At low adsorbent dose, removals are increased in the adsorption process, and performance is better with Ag 2 S-chitosan nanohybrids due to the special surface area increased. The average sizes and surface area of Ag 2 S-Chitosan nanocomposites and Ag 2 S-chitosan nanohybrids were found as 50nm, 70nm and 180.18, 238.24m 2 g -1 , respectively. In particular, Ag 2 S-Chitosan nanocomposites and Ag 2 S-chitosan nanohybrids show high maximum Clindamycin adsorption capacity (q max ) of 153.21, and 181.28mgg -1 , respectively. More strikingly, Ag 2 S-Chitosan nanocomposites and Ag 2 S-chitosan nanohybrids are also demonstrated to nearly completely remove Clindamycin from drinking water. The excellent adsorption performance along with their cost effective, convenient synthesis makes this range of adsorbents highly promising for commercial applications in drinking water and wastewater treatment. Copyright © 2017 Elsevier B.V. All rights reserved.

Date Fruits-Assisted Synthesis and Biocompatibility Assessment of Nickel Oxide Nanoparticles Anchored onto Graphene Sheets for Biomedical Applications.

PubMed

Alshatwi, Ali A; Athinarayanan, Jegan; Periasamy, Vaiyapuri Subbarayan; Alatiah, Khalid A

2017-02-01

Nanographene- and graphene-based nanohybrids have garnered attention in the biomedical community owing to their biocompatibility, excellent aqueous processability, ease of cellular uptake, facile surface functionalization, and thermal and electrical conductivities. NiO nanoparticle-graphene nanohybrid (G-NiO) was synthesized by first depositing Ni(OH) 2 onto the surface of graphene oxide (GO) sheets. The Ni(OH) 2 -GO hybrids were then reduced to G-NiO using date palm syrup at 85 °C. The prepared G-NiO nanohybrids were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy, and energy-dispersive X-ray spectroscopy (EDX). The NiO nanoparticles, with a diameter of approximately 20-30 nm, were uniformly dispersed over the surface of the graphene sheets. The G-NiO hybrids exhibit biocompatibility in human mesenchymal stem cells (hMSCs) up to 100 μg/mL. The nanohybrids do not cause any significant changes in cellular and nuclear morphologies in hMSCs. The as-synthesized nanohybrids show excellent biocompatibility and could be a promising material for biomedical applications.

Covalent functionalization of reduced graphene oxide with porphyrin by means of diazonium chemistry for nonlinear optical performance

NASA Astrophysics Data System (ADS)

Wang, Aijian; Yu, Wang; Huang, Zhipeng; Zhou, Feng; Song, Jingbao; Song, Yinglin; Long, Lingliang; Cifuentes, Marie P.; Humphrey, Mark G.; Zhang, Long; Shao, Jianda; Zhang, Chi

2016-03-01

Reduced graphene oxide (RGO)-porphyrin (TPP) nanohybrids (RGO-TPP 1 and RGO-TPP 2) were prepared by two synthetic routes that involve functionalization of the RGO using diazonium salts. The microscopic structures, morphology, photophysical properties and nonlinear optical performance of the resultant RGO-TPP nanohybrids were investigated. The covalent bonding of the porphyrin-functionalized-RGO nanohybrid materials was confirmed by Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, and thermogravimetric analysis. Attachment of the porphyrin units to the surface of the RGO by diazotization significantly improves the solubility and ease of processing of these RGO-based nanohybrid materials. Ultraviolet/visible absorption and steady-state fluorescence studies indicate considerable π-π interactions and effective photo-induced electron and/or energy transfer between the porphyrin moieties and the extended π-system of RGO. The nonlinear optical properties of RGO-TPP 1 and RGO-TPP 2 were investigated by open-aperture Z-scan measurements at 532 nm with both 4 ns and 21 ps laser pulses, the results showing that the chemical nanohybrids exhibit improved nonlinear optical properties compared to those of the benchmark material C60, and the constituent RGO or porphyrins.

Optimization of solid state anaerobic digestion of the OFMSW by digestate recirculation: A new approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Michele, Pognani, E-mail: michele.pognani@unimi.it; Giuliana, D’Imporzano, E-mail: giuliana.dimporzano@unimi.it; Gruppo Ricicla - DiSAA, Università degli Studi di Milano, Biomass and Bioenergy Lab., Parco Tecnologico Padano, Via Einstein, Loc. C.na Codazza, 26900 Lodi

2015-01-15

Highlights: • Solid State Anaerobic Digestion (SSAD) of OFMSW can be optimized by irrigation with digestate. • Digestate spreading allows keeping optimal process parameters and high hydrolysis rate. • The 18.4% of CH{sub 4} was produced in the reactor, leaving the 49.7% in the percolate. • Successive CSTR feed with percolate shows a biogas enriched in methane (more than 80%). • The proposed process allow producing the 68% of OFMSW potential CH{sub 4}, getting high quality organic amendment. - Abstract: Dry anaerobic digestion (AD) of OFMSW was optimized in order to produce biogas avoiding the use of solid inoculum. Doingmore » so the dry AD was performed irrigating the solid waste with liquid digestate (flow rate of 1:1.18–1:0.9 w/w waste/digestate; 21 d of hydraulic retention time – HRT) in order to remove fermentation products inhibiting AD process. Results indicated that a high hydrolysis rate of organic matter (OM) and partial biogas production were obtained directly during the dry AD. Hydrolysate OM was removed from digester by the percolate flow and it was subsequently used to feed a liquid anaerobic digester. During dry AD a total loss of 36.9% of total solids was recorded. Methane balance indicated that 18.4% of potential methane can be produced during dry AD and 49.7% by the percolate. Nevertheless results obtained for liquid AD digestion indicated that only 20.4% and 25.7% of potential producible methane was generated by adopting 15 and 20 days of HRT, probably due to the AD inhibition due to high presence of toxic ammonia forms in the liquid medium.« less

Fabrication mechanism and photocatalytic activity for a novel graphene oxide hybrid functionalized with tetrakis-(4-hydroxylphenyl)porphyrin and 1-pyrenesulfonic acid

NASA Astrophysics Data System (ADS)

Luo, Qiang; Ge, Riyue; Kang, Shi-Zhao; Qin, Lixia; Li, Guodong; Li, Xiangqing

2018-01-01

A new type of nanohybrid (GO/THPP/PSA) was noncovalently constructed by anchoring 5, 10, 15, 20-tetrakis-(4-hydroxylphenyl)porphyrin (THPP) and 1-pyrenesulfonic acid hydrate (PSA) in graphene oxide (GO). The assembly mechanism of the nanohybrid was explored in detail. The results showed that THPP and PSA were attached in the GO by π-π stacking interaction and hydrogen bond. Compared with pure GO, GO/THPP or GO/PSA, the GO/THPP/PSA nanohybrid showed better photocatalytic activity for hydrogen evolution. The mechanism of electron transfer in the GO/THPP/PSA nanohybrid was investigated. It was shown that light absorption and separation of electron/hole pairs were improved dramatically due to wider light response and multi-channel electrons transfer in the hybrid. The results could initiate new ideas for constructing other graphene-based functionalized materials with high photocatalytic activity.

Characterization, in Vivo and in Vitro Evaluation of Solid Dispersion of Curcumin Containing d-α-Tocopheryl Polyethylene Glycol 1000 Succinate and Mannitol.

PubMed

Song, Im-Sook; Cha, Jin-Sun; Choi, Min-Koo

2016-10-17

The aim of this study was to prepare a solid dispersion formulation of curcumin to enhance its solubility, dissolution rate, and oral bioavailability. The formulation was prepared with d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) and mannitol using solvent evaporation and freeze-drying methods, which yielded a solid dispersion composed of curcumin, TPGS, and mannitol at a ratio of 1:10:15 ( w / w / w ). The solubility and dissolution rate of the curcumin solid dispersion markedly improved compared with those of curcumin powder and a physical mixture of curcumin, TPGS, and mannitol. About 90% of the curcumin was released from the solid dispersion formulation within 10 min. After administering the formulation orally to rats, higher plasma concentrations of curcumin were observed, with increases in the maximum plasma concentration (C max ) and area under the plasma concentration-time curve (AUC) of 86- and 65-fold, respectively, compared with those of curcumin powder. The solid dispersion formulation effectively increased intestinal permeability and inhibited P-gp function. These effects increased the anti-proliferative effect of curcumin in MDA-MB-231 breast cancer cells. Moreover, 2 h incubation with curcumin powder, solid dispersion formulation, and its physical mixture resulted in differential cytotoxic effect of paclitaxel in P-gp overexpressed LLC-PK1-P-gp and MDA-MB-231 cells through the inhibition of P-gp-mediated paclitaxel efflux. In conclusion, compared with curcumin, a solid dispersion formulation of curcumin with TPGS and mannitol could be a promising option for enhancing the oral bioavailability and efficacy of curcumin through increased solubility, dissolution rate, cell permeability, and P-gp modulation.

Mesophilic co-digestion of dairy manure and lipid rich solid slaughterhouse wastes: process efficiency, limitations and floating granules formation.

PubMed

Pitk, Peep; Palatsi, Jordi; Kaparaju, Prasad; Fernández, Belén; Vilu, Raivo

2014-08-01

Lipid and protein rich solid slaughterhouse wastes are attractive co-substrates to increase volumetric biogas production in co-digestion with dairy manure. Addition of decanter sludge (DS), containing 42.2% of lipids and 35.8% of proteins (total solids basis), up to 5% of feed mixture resulted in a stable process without any indication of long chain fatty acids (LCFA) or free ammonia (NH3) inhibition and in 3.5-fold increase of volumetric biogas production. Contrary, only lipids addition as technical fat (TF) at over 2% of feed mixture resulted in formation of floating granules (FG) and process efficiency decrease. Formed FG had low biodegradability and its organic part was composed of lipids and calcium salts of LCFAs. Anaerobic digestion process intentionally directed to FG formation, could be a viable option for mitigation and control of lipids overload and derived LCFA inhibition. Copyright © 2014 Elsevier Ltd. All rights reserved.

Anti-Inflammatory Effects of Novel Standardized Solid Lipid Curcumin Formulations.

PubMed

Nahar, Pragati P; Slitt, Angela L; Seeram, Navindra P

2015-07-01

Inflammation and the presence of pro-inflammatory cytokines are associated with numerous chronic diseases such as type-2 diabetes mellitus, cardiovascular disease, Alzheimer's disease, and cancer. An overwhelming amount of data indicates that curcumin, a polyphenol obtained from the Indian spice turmeric, Curcuma longa, is a potential chemopreventive agent for treating certain cancers and other chronic inflammatory diseases. However, the low bioavailability of curcumin, partly due to its low solubility and stability in the digestive tract, limits its therapeutic applications. Recent studies have demonstrated increased bioavailability and health-promoting effects of a novel solid lipid particle formulation of curcumin (Curcumin SLCP, Longvida(®)). The goal of this study was to evaluate the aqueous solubility and in vitro anti-inflammatory effects of solid lipid curcumin particle (SLCP) formulations using lipopolysaccharide (LPS)-stimulated RAW 264.7 cultured murine macrophages. SLCPs treatment significantly decreased nitric oxide (NO) and prostaglandin-E2 (PGE2) levels at concentrations ranging from 10 to 50 μg/mL, and reduced interleukin-6 (IL-6) levels in a concentration-dependent manner. Transient transfection experiments using a nuclear factor-kappa B (NF-κB) reporter construct indicate that SLCPs significantly inhibit the transcriptional activity of NF-κB in macrophages. Taken together, these results show that in RAW 264.7 murine macrophages, SLCPs have improved solubility over unformulated curcumin, and significantly decrease the LPS-induced pro-inflammatory mediators NO, PGE2, and IL-6 by inhibiting the activation of NF-κB.

Anti-Inflammatory Effects of Novel Standardized Solid Lipid Curcumin Formulations

PubMed Central

Nahar, Pragati P.

2015-01-01

Abstract Inflammation and the presence of pro-inflammatory cytokines are associated with numerous chronic diseases such as type-2 diabetes mellitus, cardiovascular disease, Alzheimer's disease, and cancer. An overwhelming amount of data indicates that curcumin, a polyphenol obtained from the Indian spice turmeric, Curcuma longa, is a potential chemopreventive agent for treating certain cancers and other chronic inflammatory diseases. However, the low bioavailability of curcumin, partly due to its low solubility and stability in the digestive tract, limits its therapeutic applications. Recent studies have demonstrated increased bioavailability and health-promoting effects of a novel solid lipid particle formulation of curcumin (Curcumin SLCP, Longvida®). The goal of this study was to evaluate the aqueous solubility and in vitro anti-inflammatory effects of solid lipid curcumin particle (SLCP) formulations using lipopolysaccharide (LPS)-stimulated RAW 264.7 cultured murine macrophages. SLCPs treatment significantly decreased nitric oxide (NO) and prostaglandin-E2 (PGE2) levels at concentrations ranging from 10 to 50 μg/mL, and reduced interleukin-6 (IL-6) levels in a concentration-dependent manner. Transient transfection experiments using a nuclear factor-kappa B (NF-κB) reporter construct indicate that SLCPs significantly inhibit the transcriptional activity of NF-κB in macrophages. Taken together, these results show that in RAW 264.7 murine macrophages, SLCPs have improved solubility over unformulated curcumin, and significantly decrease the LPS-induced pro-inflammatory mediators NO, PGE2, and IL-6 by inhibiting the activation of NF-κB. PMID:25490740

Effect of naloxone on the antral motor response to solid food in man.

PubMed

Sharpe, G R; Rees, W D; Adrian, T E; Christofides, N D; Bloom, S R

1987-04-01

Antroduodenal motor activity was recorded in eight healthy subjects using perfused tubes connected to external strain gauge transducers. Each subject was studied over a 2.5-h period following ingestion of a solid meal, on 2 separate days. Intravenous saline was administered on one day and saline plus naloxone (40 micrograms kg-1 h-1) on the other, in randomized order. Naloxone markedly inhibited the antral motor response to food and this effect was due to decreased amplitude and contractile frequency. The duodenal motor response to solid food and the postprandial rise in serum gastrin and plasma pancreatic polypeptide were not altered by naloxone. These observations suggest that peripheral or central opiate receptors play a role in regulating the antral motor response to food.

Effect of Humic Acid on the Removal of Chromium(VI) and the Production of Solids in Iron Electrocoagulation.

PubMed

Pan, Chao; Troyer, Lyndsay D; Liao, Peng; Catalano, Jeffrey G; Li, Wenlu; Giammar, Daniel E

2017-06-06

Iron-based electrocoagulation can be highly effective for Cr(VI) removal from water supplies. However, the presence of humic acid (HA) inhibited the rate of Cr(VI) removal in electrocoagulation, with the greatest decreases in Cr(VI) removal rate at higher pH. This inhibition was probably due to the formation of Fe(II) complexes with HA that are more rapidly oxidized than uncomplexed Fe(II) by dissolved oxygen, making less Fe(II) available for reduction of Cr(VI). Close association of Fe(III), Cr(III), and HA in the solid products formed during electrocoagulation influenced the fate of both Cr(III) and HA. At pH 8, the solid products were colloids (1-200 nm) with Cr(III) and HA concentrations in the filtered fraction being quite high, while at pH 6 these concentrations were low due to aggregation of small particles. X-ray diffraction and X-ray absorption fine structure spectroscopy indicated that the iron oxides produced were a mixture of lepidocrocite and ferrihydrite, with the proportion of ferrihydrite increasing in the presence of HA. Cr(VI) was completely reduced to Cr(III) in electrocoagulation, and the coordination environment of the Cr(III) in the solids was similar regardless of the humic acid loading, pH, and dissolved oxygen level.

A conjugate of an anti-midkine single-chain variable fragment to doxorubicin inhibits tumor growth

PubMed Central

Zhao, Shuli; Zhao, Guangfeng; Xie, Hao; Huang, Yahong; Hou, Yayi

2012-01-01

Doxorubicin (DOX) was conjugated to a single-chain variable fragment (scFv) against human midkine (MK), and the conjugate (scFv-DOX) was used to target the chemotherapeutic agent to a mouse solid tumor model in which the tumor cells expressed high levels of human MK. The His-tagged recombinant scFv was expressed in bacteria, purified by metal affinity chromatography, and then conjugated to DOX using oxidative dextran (Dex) as a linker. The molecular formula of this immunoconjugate was scFv(Dex)1.3(DOX)20. In vitro apoptosis assays showed that the scFv-DOX conjugate was more cytotoxic against MK-transfected human adenocarcinoma cells (BGC823-MK) than untransfected cells (55.3 ± 2.4 vs 22.4 ± 3.8%) for three independent experiments. Nude mice bearing BGC823-MK solid tumors received scFv-DOX or equivalent doses of scFv + DOX for 2 weeks and tumor growth was more effectively inhibited by the scFv-DOX conjugate than by scFv + DOX (51.83% inhibition vs 40.81%). Histological analysis of the tumor tissues revealed that the highest levels of DOX accumulated in tumors from mice treated with scFv-DOX and this resulted in more extensive tumor cell death than in animals treated with the equivalent dose of scFv + DOX. These results show that the scFv-DOX conjugate effectively inhibited tumor growth in vivo and suggest that antigen-specific scFv may be competent drug-carriers. PMID:22267001

Pirfenidone inhibits p38-mediated generation of procoagulant microparticles by human alveolar epithelial cells.

PubMed

Neri, Tommaso; Lombardi, Stefania; Faìta, Francesca; Petrini, Silvia; Balìa, Cristina; Scalise, Valentina; Pedrinelli, Roberto; Paggiaro, Pierluigi; Celi, Alessandro

2016-08-01

Pirfenidone is a drug recently approved for idiopathic pulmonary fibrosis but its mechanisms of action are partially unknown. We have previously demonstrated that the airways of patients with idiopathic pulmonary fibrosis contain procoagulant microparticles that activate coagulation factor X to its active form, Xa, a proteinase that signals fibroblast growth and differentiation, thus potentially contributing to the pathogenesis of the disease. We also reported that in vitro exposure of human alveolar cells to H2O2 causes microparticle generation. Since p38 activation is involved in microparticle generation in some cell models and p38 inhibition is one of the mechanisms of action of pirfenidone, we investigated the hypothesis that H2O2-induced generation of microparticles by alveolar cells is dependent on p38 phosphorylation and is inhibited by pirfenidone. H2O2 stimulation of alveolar cells caused p38 phosphorylation that was inhibited by pirfenidone. The drug also inhibited H2O2 induced microparticle generation as assessed by two independent methods (solid phase thrombin generation and flow cytometry). The shedding of microparticle-bound tissue factor activity was also inhibited by pirfenidone. Inhibition of p38-mediated generation of procoagulant microparticle is a previously unrecognized mechanism of action of the antifibrotic drug, pirfenidone. Copyright © 2016 Elsevier Ltd. All rights reserved.

Vaginal lactobacilli inhibiting growth of Gardnerella vaginalis, Mobiluncus and other bacterial species cultured from vaginal content of women with bacterial vaginosis.

PubMed

Skarin, A; Sylwan, J

1986-12-01

On a solid agar medium the growth-inhibitory effect of 9 Lactobacillus strains cultured from vaginal content was tested on bacteria cultured from vaginal content of women with bacterial vaginosis: Mobiluncus, Gardnerella vaginalis, Bacteroides and anaerobic cocci. Inhibition zones were observed in the growth of all of the strains isolated from women with bacterial vaginosis around all lactobacilli. The inhibitory effect of the lactobacilli was further tested on various anaerobic and facultatively anaerobic species, both type strains and fresh extragenitally cultured strains. Four Bacteroides fragilis strains as well as 2 out of 4 Staphylococcus aureus strains were clearly inhibited by the lactobacilli. The inhibition zones were generally wider at pH 5.5 than at 6.0. For all inhibited strains, (the S. aureus excepted) a low pH on the agar around the lactobacilli correlated to wider growth-inhibition zones.

Enhanced electrocatalytic activity of graphene-gold nanoparticles hybrids for peroxynitrite electrochemical detection on hemin-based electrode.

PubMed

Wang, Beibei; Ji, Xueping; Ren, Jujie; Ni, Ruixing; Wang, Lin

2017-12-01

A simple, ultrasensitive peroxynitrite anion (ONOO - ) electrochemical sensing platform was developed by immobilizing hemin on a density controllable electrochemically reduced graphene oxide-Au nanoparticles (ERGO-AuNPs) nanohybrids. The ERGO-AuNPs in situ nanohybrids were produced onto a glass carbon electrode (GCE) by one-step electrodeposition, the density of which could be easily controlled by electrodeposited time. The morphology of ERGO-AuNPs nanohybrids was characterized by a scanning electron microscope (SEM). The ERGO-AuNPs nanohybrids showed a high electrocatalytic activity for immobilized-hemin, because the nanostructures hybrids could effectively promote electron transfer rate between hemin and the electrode. Due to nanohybrids-enhanced catalytic effect for hemin, they were firstly selected for use as a highly sensitive electrochemical platform for ONOO - detection. The resulted sensor showed a high electrocatalytic activity toward ONOO - oxidation, being free from the electroactive interferents, including nitrite, nitrate, dopamine and uric acid at an applied potential of 0.7V. The sensor exhibited a high sensitivity of 123.1nAμM -1 and a lower detection limit of 0.1μM, and a wide linear range of 2.4×10 -6 to 5.5×10 -5 M, which could be attributed to the synergy between ERGO and AuNPs in hybrids. The nanohybrids in situ preparation and ONOO - detection methods would be beneficial to developing other sensing interface and have promising applications in biological molecules analysis and clinical diagnostic. Copyright © 2017 Elsevier B.V. All rights reserved.

Photoinduced Dynamics and Toxicity of a Cancer Drug in Proximity of Inorganic Nanoparticles under Visible Light.

PubMed

Chaudhuri, Siddhi; Sardar, Samim; Bagchi, Damayanti; Dutta, Shreyasi; Debnath, Sushanta; Saha, Partha; Lemmens, Peter; Pal, Samir Kumar

2016-01-18

Drug sensitization with various inorganic nanoparticles (NPs) has proved to be a promising and an emergent concept in the field of nanomedicine. Rose bengal (RB), a notable photosensitizer, triggers the formation of reactive oxygen species under green-light irradiation, and consequently, it induces cytotoxicity and cell death. In the present study, the effect of photoinduced dynamics of RB upon complexation with semiconductor zinc oxide NPs is explored. To accomplish this, we successfully synthesized nanohybrids of RB with ZnO NPs with a particle size of 24 nm and optically characterized them. The uniform size and integrity of the particles were confirmed by high-resolution transmission electron microscopy. UV/Vis absorption and steady-state fluorescence studies reveal the formation of the nanohybrids. ultrafast picosecond-resolved fluorescence studies of RB-ZnO nanohybrids demonstrate an efficient electron transfer from the photoexcited drug to the semiconductor NPs. Picosecond-resolved Förster resonance energy transfer from ZnO NPs to RB unravel the proximity of the drug to the semiconductor at the molecular level. The photoinduced ROS formation was monitored using a dichlorofluorescin oxidation assay, which is a conventional oxidative stress indicator. It is observed that the ROS generation under green light illumination is greater at low concentrations of RB-ZnO nanohybrids compared with free RB. Substantial photodynamic activity of the nanohybrids in bacterial and fungal cell lines validated the in vitro toxicity results. Furthermore, the cytotoxic effect of the nanohybrids in HeLa cells, which was monitored by MTT assay, is also noteworthy. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Combined MTOR and autophagy inhibition: phase I trial of hydroxychloroquine and temsirolimus in patients with advanced solid tumors and melanoma.

PubMed

Rangwala, Reshma; Chang, Yunyoung C; Hu, Janice; Algazy, Kenneth M; Evans, Tracey L; Fecher, Leslie A; Schuchter, Lynn M; Torigian, Drew A; Panosian, Jeffrey T; Troxel, Andrea B; Tan, Kay-See; Heitjan, Daniel F; DeMichele, Angela M; Vaughn, David J; Redlinger, Maryann; Alavi, Abass; Kaiser, Jonathon; Pontiggia, Laura; Davis, Lisa E; O'Dwyer, Peter J; Amaravadi, Ravi K

2014-08-01

The combination of temsirolimus (TEM), an MTOR inhibitor, and hydroxychloroquine (HCQ), an autophagy inhibitor, augments cell death in preclinical models. This phase 1 dose-escalation study evaluated the maximum tolerated dose (MTD), safety, preliminary activity, pharmacokinetics, and pharmacodynamics of HCQ in combination with TEM in cancer patients. In the dose escalation portion, 27 patients with advanced solid malignancies were enrolled, followed by a cohort expansion at the top dose level in 12 patients with metastatic melanoma. The combination of HCQ and TEM was well tolerated, and grade 3 or 4 toxicity was limited to anorexia (7%), fatigue (7%), and nausea (7%). An MTD was not reached for HCQ, and the recommended phase II dose was HCQ 600 mg twice daily in combination with TEM 25 mg weekly. Other common grade 1 or 2 toxicities included fatigue, anorexia, nausea, stomatitis, rash, and weight loss. No responses were observed; however, 14/21 (67%) patients in the dose escalation and 14/19 (74%) patients with melanoma achieved stable disease. The median progression-free survival in 13 melanoma patients treated with HCQ 1200mg/d in combination with TEM was 3.5 mo. Novel 18-fluorodeoxyglucose positron emission tomography (FDG-PET) measurements predicted clinical outcome and provided further evidence that the addition of HCQ to TEM produced metabolic stress on tumors in patients that experienced clinical benefit. Pharmacodynamic evidence of autophagy inhibition was evident in serial PBMC and tumor biopsies only in patients treated with 1200 mg daily HCQ. This study indicates that TEM and HCQ is safe and tolerable, modulates autophagy in patients, and has significant antitumor activity. Further studies combining MTOR and autophagy inhibitors in cancer patients are warranted.

Ganoderma lucidum total triterpenes attenuate DLA induced ascites and EAC induced solid tumours in Swiss albino mice.

PubMed

Smina, T P; Mathew, J; Janardhanan, K K

2016-04-30

G. lucidum total triterpenes were assessed for its apoptosis-inducing and anti-tumour activities. The ability of the total triterpenes to induce apoptosis was evaluated in Dalton's lymphoma ascites (DLA) and Ehrlich's ascites carcinoma (EAC) cell lines. Total triterpenes were found to be highly cytotoxic to DLA and EAC cell lines with IC50 values 5 ± 0.32 and 7.9 ± 0.2 µg/ml respectively. Total triterpenes induced apoptosis in both cell lines which is evident from the DNA fragmentation assay. Anti-tumour activity was accessed using DLA induced solid and EAC induced ascites tumour models in Swiss albino mice. Administration of 10, 50 and 100 mg/kg b. wt. total triterpenes showed 11.86, 27.27 and 40.57% increase in life span of animals in ascites tumour model. Treatment with 10, 50 and 100 mg/kg b. wt. total triterpenes exhibited 76.86, 85.01 and 91.03% inhibition in tumour volume and 67.96, 72.38 and 77.90% inhibition in tumour weight respectively in the solid tumour model. The study reveals the significant dose-dependent anti-tumour activity of total triterpenes in both models. Total triterpenes were more active against the solid tumour than the ascites tumour. The anti-oxidant potential and ability to induce cell-specific apoptosis could be contributing to its anti-tumour activities.

Silver nanoparticles anchored reduced graphene oxide for enhanced electrocatalytic activity towards methanol oxidation

NASA Astrophysics Data System (ADS)

Kumar, Sanjeev; Mahajan, Mani; Singh, Rajinder; Mahajan, Aman

2018-02-01

In this report, silver nanoparticles (Ag NPs) anchored reduced graphene oxide (rGO) sheets (rGO/Ag) nanohybrid has been explored as anode material in direct methanol fuel cells (DMFCs). The synthesized rGO/Ag nanohybrid is characterized by XRD, XPS, FTIR spectroscopy and HRTEM techniques. Cyclic voltammograms demonstrate that the rGO/Ag nanohybrid exhibits higher electrocatalytic activity in comparison to rGO sheets for methanol oxidation reaction (MOR). This enhancement is attributed to the synergetic effect produced by the presence of more active sites provided by Ag NPs anchored on a conducting network of large surface area rGO sheets.

Magnetic and optoelectronic properties of gold nanocluster-thiophene assembly.

PubMed

Qin, Wei; Lohrman, Jessica; Ren, Shenqiang

2014-07-07

Nanohybrids consisting of Au nanocluster and polythiophene nanowire assemblies exhibit unique thermal-responsive optical behaviors and charge-transfer controlled magnetic and optoelectronic properties. The ultrasmall Au nanocluster enhanced photoabsorption and conductivity effectively improves the photocurrent of nanohybrid based photovoltaics, leading to an increase of power conversion efficiency by 14 % under AM 1.5 illumination. In addition, nanohybrids exhibit electric field controlled spin resonance and magnetic field sensing behaviors, which open up the potential of charge-transfer complex system where the magnetism and optoelectronics interact. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development and Characterization of a High-Solids Deacetylation Process

DOE PAGES

Shekiro, III, Joseph; Chen, Xiaowen; Smith, Holly; ...

2016-05-20

that despite the upfront reduction in carbohydrate loss during deacetylation, the overall process sugar yields were depressed by the high-solids, low alkali process relative to the historical control. Consequently, ethanol titers were reduced, though strong fermentation performance was still observed, indicating that 70 % acetate removal is sufficient to depress acetic acid concentrations to a level that does not substantially inhibit ethanol fermentation by rZymomo nas.« less

One-pot synthesis of CdS nanocrystals hybridized with single-layer transition-metal dichalcogenide nanosheets for efficient photocatalytic hydrogen evolution.

PubMed

Chen, Junze; Wu, Xue-Jun; Yin, Lisha; Li, Bing; Hong, Xun; Fan, Zhanxi; Chen, Bo; Xue, Can; Zhang, Hua

2015-01-19

Exploration of low-cost and earth-abundant photocatalysts for highly efficient solar photocatalytic water splitting is of great importance. Although transition-metal dichalcogenides (TMDs) showed outstanding performance as co-catalysts for the hydrogen evolution reaction (HER), designing TMD-hybridized photocatalysts with abundant active sites for the HER still remains challenge. Here, a facile one-pot wet-chemical method is developed to prepare MS2-CdS (M=W or Mo) nanohybrids. Surprisedly, in the obtained nanohybrids, single-layer MS2 nanosheets with lateral size of 4-10 nm selectively grow on the Cd-rich (0001) surface of wurtzite CdS nanocrystals. These MS2-CdS nanohybrids possess a large number of edge sites in the MS2 layers, which are active sites for the HER. The photocatalytic performances of WS2-CdS and MoS2-CdS nanohybrids towards the HER under visible light irradiation (>420 nm) are about 16 and 12 times that of pure CdS, respectively. Importantly, the MS2-CdS nanohybrids showed enhanced stability after a long-time test (16 h), and 70% of catalytic activity still remained. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Covalent functionalization of reduced graphene oxide with porphyrin by means of diazonium chemistry for nonlinear optical performance

PubMed Central

Wang, Aijian; Yu, Wang; Huang, Zhipeng; Zhou, Feng; Song, Jingbao; Song, Yinglin; Long, Lingliang; Cifuentes, Marie P.; Humphrey, Mark G.; Zhang, Long; Shao, Jianda; Zhang, Chi

2016-01-01

Reduced graphene oxide (RGO)-porphyrin (TPP) nanohybrids (RGO-TPP 1 and RGO-TPP 2) were prepared by two synthetic routes that involve functionalization of the RGO using diazonium salts. The microscopic structures, morphology, photophysical properties and nonlinear optical performance of the resultant RGO-TPP nanohybrids were investigated. The covalent bonding of the porphyrin-functionalized-RGO nanohybrid materials was confirmed by Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, and thermogravimetric analysis. Attachment of the porphyrin units to the surface of the RGO by diazotization significantly improves the solubility and ease of processing of these RGO-based nanohybrid materials. Ultraviolet/visible absorption and steady-state fluorescence studies indicate considerable π-π interactions and effective photo-induced electron and/or energy transfer between the porphyrin moieties and the extended π-system of RGO. The nonlinear optical properties of RGO-TPP 1 and RGO-TPP 2 were investigated by open-aperture Z-scan measurements at 532 nm with both 4 ns and 21 ps laser pulses, the results showing that the chemical nanohybrids exhibit improved nonlinear optical properties compared to those of the benchmark material C60, and the constituent RGO or porphyrins. PMID:27011265

Effect of Drag Reducing Polymer and Suspended Solid on the Rate of Diffusion Controlled Corrosion in 90° Copper Elbow

NASA Astrophysics Data System (ADS)

Fouad, Mohamed Ahmed; Zewail, Taghreed Mohamed; Amine, Nieven Kamal Abbes

2017-06-01

Rate of diffusion controlled corrosion in 90° Copper Elbow acidified dichromate has been investigated in relation to the following parameters: effect of solution velocity in the absence and presence of drag- reducing polymer on the rate of diffusion controlled corrosion, and effect of the presence of suspended solids on the rate of diffusion controlled corrosion. It was found that the presence of drag reducing polymer inhibited the rate of mass transfer, while the presence of suspended solid increased significantly the rate of mass transfer.

Anti-HCV effect of Lentinula edodes mycelia solid culture extracts and low-molecular-weight lignin.

PubMed

Matsuhisa, Koji; Yamane, Seiji; Okamoto, Toru; Watari, Akihiro; Kondoh, Masuo; Matsuura, Yoshiharu; Yagi, Kiyohito

2015-06-19

Lentinula edodes mycelia solid culture extract (MSCE) contains several bioactive molecules, including some polyphenolic compounds, which exert immunomodulatory, antitumor, and hepatoprotective effects. In this study, we examined the anti-hepatitis C virus (HCV) activity of MSCE and low-molecular-weight lignin (LM-lignin), which is the active component responsible for the hepatoprotective effect of MSCE. Both MSCE and LM-lignin inhibited the entry of two HCV pseudovirus (HCVpv) types into Huh7.5.1 cells. LM-lignin inhibited HCVpv entry at a lower concentration than MSCE and inhibited the entry of HCV particles in cell culture (HCVcc). MSCE also inhibited HCV subgenome replication. LM-lignin had no effect on HCV replication, suggesting that MSCE contains additional active substances. We demonstrate here for the first time the anti-HCV effects of plant-derived LM-lignin and MSCE. The hepatoprotective effect of LM-lignin suggests that lignin derivatives, which can be produced in abundance from existing plant resources, may be effective in the treatment of HCV-related diseases. Copyright © 2015 Elsevier Inc. All rights reserved.

A novel quasi-solid state electrolyte with highly effective polysulfide diffusion inhibition for lithium-sulfur batteries

PubMed Central

Zhong, Hai; Wang, Chunhua; Xu, Zhibin; Ding, Fei; Liu, Xinjiang

2016-01-01

Polymer solid state electrolytes are actively sought for their potential application in energy storage devices, particularly lithium metal rechargeable batteries. Herein, we report a polymer with high concentration salts as a quasi-solid state electrolyte used for lithium-sulfur cells, which shows an ionic conductivity of 1.6 mS cm−1 at room temperature. The cycling performance of Li-S battery with this electrolyte shows a long cycle life (300 cycles) and high coulombic efficiency (>98%), without any consuming additives in the electrolyte. Moreover, it also shows a remarkably decreased self-discharge (only 0.2%) after storage for two weeks at room temperature. The reason can be attributed to that the electrolyte can suppress polysulfide anions diffusion, due to the high ratio oxygen atoms with negative charges which induce an electrical repulsion to the polysulfide anions, and their relatively long chains which can provide additional steric hindrance. Thus, the polysulfide anions can be located around carbon particles, which result in remarkably improved overall electrochemical performance, and also the electrolyte have a function of suppress the formation of lithium dendrites on the lithium anode surface. PMID:27146645

Taurine zinc solid dispersions attenuate doxorubicin-induced hepatotoxicity and cardiotoxicity in rats.

PubMed

Wang, Yu; Mei, Xueting; Yuan, Jingquan; Lu, Wenping; Li, Binglong; Xu, Donghui

2015-11-15

The clinical efficacy of anthracycline anti-neoplastic agents is limited by cardiac and hepatic toxicities. The aim of this study was to assess the hepatoprotective and cardioprotective effects of taurine zinc solid dispersions, which is a newly-synthesized taurine zinc compound, against doxorubicin-induced toxicity in Sprague-Dawley rats intraperitoneally injected with doxorubicin hydrochloride (3mg/kg) three times a week (seven injections) over 28 days. Hemodynamic parameters, levels of liver toxicity markers and oxidative stress were assessed. Taurine zinc significantly attenuated the reductions in blood pressure, left ventricular pressure and ± dp/dtmax, increases in serum alanine aminotransferase and aspartate aminotransferase activities, and reductions in serum Zn(2+) and albumin levels (P<0.05 or 0.01) induced by doxorubicin. In rats treated with doxorubicin, taurine zinc dose-dependently increased liver superoxide dismutase activity and glutathione concentration, and decreased malondialdehyde level (P<0.01). qBase(+) was used to evaluate the stability of eight candidate reference genes for real-time quantitative reverse-transcription PCR. Taurine zinc dose-dependently increased liver heme oxygenase-1 and UDP-glucuronyl transferase mRNA and protein expression (P<0.01). Western blotting demonstrated that taurine zinc inhibited c-Jun N-terminal kinase phosphorylation by upregulating dual-specificity phosphoprotein phosphatase-1. Additionally, taurine zinc inhibited cardiomyocyte apoptosis as there was decreased TUNEL/DAPI positivity and protein expression of caspase-3. These results indicate that taurine zinc solid dispersions prevent the side-effects of anthracycline-based anticancer therapy. The mechanisms might be associated with the enhancement of antioxidant defense system partly through activating transcription to synthesize endogenous phase II medicine enzymes and anti-apoptosis through inhibiting JNK phosphorylation. Copyright © 2015 Elsevier Inc

Effective seed-assisted synthesis of gold nanoparticles anchored nitrogen-doped graphene for electrochemical detection of glucose and dopamine.

PubMed

Thanh, Tran Duy; Balamurugan, Jayaraman; Lee, Seung Hee; Kim, Nam Hoon; Lee, Joong Hee

2016-07-15

A novel gold nanoparticle-anchored nitrogen-doped graphene (AuNP/NG) nanohybrid was synthesized through a seed-assisted growth method, as an effective electrocatalyst for glucose and dopamine detection. The AuNP/NG nanohybrids exhibited high sensitivity and selectivity toward glucose and dopamine sensing applications. The as-synthesized nanohybrids exhibited excellent catalytic activity toward glucose, with a linear response throughout the concentration range from 40μM to 16.1mM, a detection limit of 12μM, and a short response time (∼ 10s). It also exhibited an excellent response toward DA, with a wide detection range from 30nM to 48μM, a low detection limit of 10nM, and a short response time (∼ 8s). Furthermore, it also showed long-term stability and high selectivity for the target analytes. These results imply that such nanohybrids show a great potential for electrochemical biosensing application. Copyright © 2016 Elsevier B.V. All rights reserved.

Combined autophagy and HDAC inhibition: a phase I safety, tolerability, pharmacokinetic, and pharmacodynamic analysis of hydroxychloroquine in combination with the HDAC inhibitor vorinostat in patients with advanced solid tumors.

PubMed

Mahalingam, Devalingam; Mita, Monica; Sarantopoulos, John; Wood, Leslie; Amaravadi, Ravi K; Davis, Lisa E; Mita, Alain C; Curiel, Tyler J; Espitia, Claudia M; Nawrocki, Steffan T; Giles, Francis J; Carew, Jennifer S

2014-08-01

We previously reported that inhibition of autophagy significantly augmented the anticancer activity of the histone deacetylase (HDAC) inhibitor vorinostat (VOR) through a cathepsin D-mediated mechanism. We thus conducted a first-in-human study to investigate the safety, preliminary efficacy, pharmacokinetics (PK), and pharmacodynamics (PD) of the combination of the autophagy inhibitor hydroxychloroquine (HCQ) and VOR in patients with advanced solid tumors. Of 27 patients treated in the study, 24 were considered fully evaluable for study assessments and toxicity. Patients were treated orally with escalating doses of HCQ daily (QD) (d 2 to 21 of a 21-d cycle) in combination with 400 mg VOR QD (d one to 21). Treatment-related adverse events (AE) included grade 1 to 2 nausea, diarrhea, fatigue, weight loss, anemia, and elevated creatinine. Grade 3 fatigue and/or myelosuppression were observed in a minority of patients. Fatigue and gastrointestinal AE were dose-limiting toxicities. Six-hundred milligrams HCQ and 400 mg VOR was established as the maximum tolerated dose and recommended phase II regimen. One patient with renal cell carcinoma had a confirmed durable partial response and 2 patients with colorectal cancer had prolonged stable disease. The addition of HCQ did not significantly impact the PK profile of VOR. Treatment-related increases in the expression of CDKN1A and CTSD were more pronounced in tumor biopsies than peripheral blood mononuclear cells. Based on the safety and preliminary efficacy of this combination, additional clinical studies are currently being planned to further investigate autophagy inhibition as a new approach to increase the efficacy of HDAC inhibitors.

Evaluation of epirubicin in thermogelling and bioadhesive liquid and solid suppository formulations for rectal administration.

PubMed

Lo, Yu-Li; Lin, Yijun; Lin, Hong-Ru

2013-12-31

Temperature sensitive Pluronic (Plu) and pH-sensitive polyacrylic acid (PAA) were successfully mixed in different ratios to form in situ gelling formulations for colon cancer therapy. The major formulations were prepared as the liquid and solid suppository dosage forms. Epirubicin (Epi) was chosen as a model anticancer drug. In vitro characterization and in vivo pharmacokinetics and therapeutic efficacy of Epi in six Plu/PAA formulations were evaluated. Our in vitro data indicate that Epi in Plu 14%/PAA 0.75% of both solid and liquid suppositories possess significant cytotoxicity, strong bioadhesive force, long-term appropriate suppository base, sustained release, and high accumulation of Epi in rat rectums. These solid and liquid suppositories were retained in the upper rectum of Sprague-Dawley (SD) rats for at least 12 h. An in vivo pharmacokinetic study using SD rats showed that after rectal administration of solid and liquid suppositories, Epi had greater area under the curve and higher relative bioavailability than in a rectal solution. These solid and liquid suppositories exhibited remarkable inhibition on the tumor growth of CT26 bearing Balb/c mice in vivo. Our findings suggest that in situ thermogelling and mucoadhesive suppositories demonstrate a great potential as colon anticancer delivery systems for protracted release of chemotherapeutic agents.

Evaluation of Epirubicin in Thermogelling and Bioadhesive Liquid and Solid Suppository Formulations for Rectal Administration

PubMed Central

Lo, Yu-Li; Lin, Yijun; Lin, Hong-Ru

2014-01-01

Temperature sensitive Pluronic (Plu) and pH-sensitive polyacrylic acid (PAA) were successfully mixed in different ratios to form in situ gelling formulations for colon cancer therapy. The major formulations were prepared as the liquid and solid suppository dosage forms. Epirubicin (Epi) was chosen as a model anticancer drug. In vitro characterization and in vivo pharmacokinetics and therapeutic efficacy of Epi in six Plu/PAA formulations were evaluated. Our in vitro data indicate that Epi in Plu 14%/PAA 0.75% of both solid and liquid suppositories possess significant cytotoxicity, strong bioadhesive force, long-term appropriate suppository base, sustained release, and high accumulation of Epi in rat rectums. These solid and liquid suppositories were retained in the upper rectum of Sprague-Dawley (SD) rats for at least 12 h. An in vivo pharmacokinetic study using SD rats showed that after rectal administration of solid and liquid suppositories, Epi had greater area under the curve and higher relative bioavailability than in a rectal solution. These solid and liquid suppositories exhibited remarkable inhibition on the tumor growth of CT26 bearing Balb/c mice in vivo. Our findings suggest that in situ thermogelling and mucoadhesive suppositories demonstrate a great potential as colon anticancer delivery systems for protracted release of chemotherapeutic agents. PMID:24384838

Preclinical efficacy of maternal embryonic leucine-zipper kinase (MELK) inhibition in acute myeloid leukemia.

PubMed

Alachkar, Houda; Mutonga, Martin B G; Metzeler, Klaus H; Fulton, Noreen; Malnassy, Gregory; Herold, Tobias; Spiekermann, Karsten; Bohlander, Stefan K; Hiddemann, Wolfgang; Matsuo, Yo; Stock, Wendy; Nakamura, Yusuke

2014-12-15

Maternal embryonic leucine-zipper kinase (MELK), which was reported to be frequently up-regulated in various types of solid cancer, plays critical roles in formation and maintenance of cancer stem cells. However, little is known about the relevance of this kinase in hematologic malignancies. Here we report characterization of possible roles of MELK in acute myeloid leukemia (AML). MELK is expressed in AML cell lines and AML blasts with higher levels in less differentiated cells. MELK is frequently upregulated in AML with complex karyotypes and is associated with worse clinical outcome. MELK knockdown resulted in growth inhibition and apoptosis of leukemic cells. Hence, we investigated the potent anti-leukemia activity of OTS167, a small molecule MELK kinase inhibitor, in AML, and found that the compound induced cell differentiation and apoptosis as well as decreased migration of AML cells. MELK expression was positively correlated with the expression of FOXM1 as well as its downstream target genes. Furthermore, MELK inhibition resulted in downregulation of FOXM1 activity and the expression of its downstream targets. Taken together, and given that OTS167 is undergoing a phase I clinical trial in solid cancer, our study warrants clinical evaluation of this compound as a novel targeted therapy for AML patients.

Preclinical efficacy of maternal embryonic leucine-zipper kinase (MELK) inhibition in acute myeloid leukemia

PubMed Central

Alachkar, Houda; Mutonga, Martin B.G.; Metzeler, Klaus H.; Fulton, Noreen; Malnassy, Gregory; Herold, Tobias; Spiekermann, Karsten; Bohlander, Stefan K.; Hiddemann, Wolfgang; Matsuo, Yo; Stock, Wendy; Nakamura, Yusuke

2014-01-01

Maternal embryonic leucine-zipper kinase (MELK), which was reported to be frequently up-regulated in various types of solid cancer, plays critical roles in formation and maintenance of cancer stem cells. However, little is known about the relevance of this kinase in hematologic malignancies. Here we report characterization of possible roles of MELK in acute myeloid leukemia (AML). MELK is expressed in AML cell lines and AML blasts with higher levels in less differentiated cells. MELK is frequently upregulated in AML with complex karyotypes and is associated with worse clinical outcome. MELK knockdown resulted in growth inhibition and apoptosis of leukemic cells. Hence, we investigated the potent anti-leukemia activity of OTS167, a small molecule MELK kinase inhibitor, in AML, and found that the compound induced cell differentiation and apoptosis as well as decreased migration of AML cells. MELK expression was positively correlated with the expression of FOXM1 as well as its downstream target genes. Furthermore, MELK inhibition resulted in downregulation of FOXM1 activity and the expression of its downstream targets. Taken together, and given that OTS167 is undergoing a phase I clinical trial in solid cancer, our study warrants clinical evaluation of this compound as a novel targeted therapy for AML patients. PMID:25365263

Solids fluidizer-injector

DOEpatents

Bulicz, Tytus R.

1990-01-01

An apparatus and process for fluidizing solid particles by causing rotary motion of the solid particles in a fluidizing chamber by a plurality of rotating projections extending from a rotatable cylinder end wall interacting with a plurality of fixed projections extending from an opposite fixed end wall and passing the solid particles through a radial feed orifice open to the solids fluidizing chamber on one side and a solid particle utilization device on the other side. The apparatus and process are particularly suited for obtaining intermittent feeding with continual solids supply to the fluidizing chamber. The apparatus and process are suitable for injecting solid particles, such as coal, to an internal combustion engine.

Solids fluidizer-injector

DOEpatents

Bulicz, T.R.

1990-04-17

An apparatus and process are described for fluidizing solid particles by causing rotary motion of the solid particles in a fluidizing chamber by a plurality of rotating projections extending from a rotatable cylinder end wall interacting with a plurality of fixed projections extending from an opposite fixed end wall and passing the solid particles through a radial feed orifice open to the solids fluidizing chamber on one side and a solid particle utilization device on the other side. The apparatus and process are particularly suited for obtaining intermittent feeding with continual solids supply to the fluidizing chamber. The apparatus and process are suitable for injecting solid particles, such as coal, to an internal combustion engine. 3 figs.

Human CAR T cells with cell-intrinsic PD-1 checkpoint blockade resist tumor-mediated inhibition

PubMed Central

Cherkassky, Leonid; Morello, Aurore; Villena-Vargas, Jonathan; Feng, Yang; Dimitrov, Dimiter S.; Jones, David R.; Sadelain, Michel; Adusumilli, Prasad S.

2016-01-01

Following immune attack, solid tumors upregulate coinhibitory ligands that bind to inhibitory receptors on T cells. This adaptive resistance compromises the efficacy of chimeric antigen receptor (CAR) T cell therapies, which redirect T cells to solid tumors. Here, we investigated whether programmed death-1–mediated (PD-1–mediated) T cell exhaustion affects mesothelin-targeted CAR T cells and explored cell-intrinsic strategies to overcome inhibition of CAR T cells. Using an orthotopic mouse model of pleural mesothelioma, we determined that relatively high doses of both CD28- and 4-1BB–based second-generation CAR T cells achieved tumor eradication. CAR-mediated CD28 and 4-1BB costimulation resulted in similar levels of T cell persistence in animals treated with low T cell doses; however, PD-1 upregulation within the tumor microenvironment inhibited T cell function. At lower doses, 4-1BB CAR T cells retained their cytotoxic and cytokine secretion functions longer than CD28 CAR T cells. The prolonged function of 4-1BB CAR T cells correlated with improved survival. PD-1/PD-1 ligand [PD-L1] pathway interference, through PD-1 antibody checkpoint blockade, cell-intrinsic PD-1 shRNA blockade, or a PD-1 dominant negative receptor, restored the effector function of CD28 CAR T cells. These findings provide mechanistic insights into human CAR T cell exhaustion in solid tumors and suggest that PD-1/PD-L1 blockade may be an effective strategy for improving the potency of CAR T cell therapies. PMID:27454297

Curcumin/turmeric solubilized in sodium hydroxide inhibits HNE protein modification--an in vitro study.

PubMed

Kurien, Biji T; Scofield, R Hal

2007-03-21

Free radical mediated lipid peroxidation has been implicated in multiple diseases. A major oxidation by-product of this deleterious process is 4-hydroxy-2-nonenal (HNE). HNE is cytotoxic, mutagenic and genotoxic and is involved in disease pathogenesis. Curcumin, a non-steroidal anti-inflammatory agent (occurring as the yellow pigment found in the rhizomes of the perennial herb Curcuma longa known as turmeric), has emerged as the newest "nutraceutical" agent that has been shown to be efficacious against colon cancer and other disorders, including correcting cystic fibrosis defects. Since curcumin has been reported to have anti-oxidant properties we hypothesized that it will inhibit HNE-modification of a protein substrate. Using an ELISA that employed HNE-modification of solid phase antigen following immobilization, we found that the curcumin solubilized in dilute alkali (5mM sodium hydroxide, pH 11) inhibited HNE-protein modification by 65%. Turmeric also inhibited HNE-protein modification similarly (65%) but at a much lower alkali level (130muM sodium hydroxide, pH 7.6). Alkali by itself (5mM sodium hydroxide, pH 11) was found to enhance HNE modification by as much as 267%. Curcumin/turmeric has to inhibit this alkali enhanced HNE-modification prior to inhibiting the normal HNE protein modification induced by HNE. Thus, inhibition of HNE-modification could be a mechanism by which curcumin exerts its antioxidant effects. The pH at which the inhibition of HNE modification of substrate was observed was close to the physiological pH, making this formulation of curcumin potentially useful practically.

Adhesion and inactivation of Gram-negative and Gram-positive bacteria on photoreactive TiO2/polymer and Ag-TiO2/polymer nanohybrid films

NASA Astrophysics Data System (ADS)

Tallósy, Szabolcs Péter; Janovák, László; Nagy, Elisabeth; Deák, Ágota; Juhász, Ádám; Csapó, Edit; Buzás, Norbert; Dékány, Imre

2016-05-01

The aim of this study was to develop photoreactive surface coatings, possessing antibacterial properties and can be activated under visible light illumination (λmax = 405 nm) using LED-light source. The photocatalytically active titanium dioxide (TiO2) was functionalized with silver nanoparticles (Ag NPs) and immobilized in polyacrylate based nanohybrid thin film in order to facilitate visible light activity (λAg/TiO2,max = 500 nm). First, the photocatalytic activity was modelled by following ethanol vapor degradation. The plasmonic functionalization resulted in 15% enhancement of the activity compared to pure TiO2. The photoreactive antimicrobial (5 log reduction of cfu in 2 h) surface coatings are able to inactivate clinically relevant pathogen strains (methicillin resistant Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa) within short time (60-120 min) due to the formed and quantified reactive oxygen species (ROS). The existence of electrostatic interactions between the negatively charged bacteria (from -0.89 to -3.19 μeq/109 cfu) and positively charged photocatalyst particles (in the range of +0.38 and +12.3 meq/100 g) was also proven by charge titration measurements. The surface inactivation of the bacteria and the photocatalytic degradation of the cell wall component were also confirmed by fluorescence and transmission electron microscopic observations, respectively. According to the results an effective sterilizing system and prevention strategy can be developed and carried out against dangerous microorganisms in health care.

A degradation model for high kitchen waste content municipal solid waste.

PubMed

Chen, Yunmin; Guo, Ruyang; Li, Yu-Chao; Liu, Hailong; Zhan, Tony Liangtong

2016-12-01

Municipal solid waste (MSW) in developing countries has a high content of kitchen waste (KW), and therefore contains large quantities of water and non-hollocellulose degradable organics. The degradation of high KW content MSW cannot be well simulated by the existing degradation models, which are mostly established for low KW content MSW in developed countries. This paper presents a two-stage anaerobic degradation model for high KW content MSW with degradations of hollocellulose, sugars, proteins and lipids considered. The ranges of the proportions of chemical compounds in MSW components are summarized with the recommended values given. Waste components are grouped into rapidly or slowly degradable categories in terms of the degradation rates under optimal water conditions for degradation. In the proposed model, the unionized VFA inhibitions of hydrolysis/acidogenesis and methanogenesis are considered as well as the pH inhibition of methanogenesis. Both modest and serious VFA inhibitions can be modeled by the proposed model. Default values for the parameters in the proposed method can be used for predictions of degradations of both low and high KW content MSW. The proposed model was verified by simulating two laboratory experiments, in which low and high KW content MSW were used, respectively. The simulated results are in good agreement with the measured data of the experiments. The results show that under low VFA concentrations, the pH inhibition of methanogenesis is the main inhibition to be considered, while the inhibitions of both hydrolysis/acidogenesis and methanogenesis caused by unionized VFA are significant under high VFA concentrations. The model is also used to compare the degradation behaviors of low and high KW content MSW under a favorable environmental condition, and it shows that the gas potential of high KW content MSW releases more quickly. Copyright © 2016 Elsevier Ltd. All rights reserved.

Anxiety and retrieval inhibition: support for an enhanced inhibition account.

PubMed

Nuñez, Mia; Gregory, Josh; Zinbarg, Richard E

2017-02-01

Retrieval inhibition of negative associations is important for exposure therapy for anxiety, but the relationship between memory inhibition and anxiety is not well understood-anxiety could either be associated with enhanced or deficient inhibition. The present study tested these two competing hypotheses by measuring retrieval inhibition of negative stimuli by related neutral stimuli. Non-clinically anxious undergraduates completed measures of trait and state anxiety and completed a retrieval induced forgetting task. Adaptive forgetting varied with state anxiety. Low levels of state anxiety were associated with no evidence for retrieval inhibition for either threatening or non-threatening categories. Participants in the middle tertile of state anxiety scores exhibited retrieval inhibition for non-threatening categories but not for threatening categories. Participants in the highest tertile of state anxiety, however, exhibited retrieval inhibition for both threatening and non-threatening categories with the magnitude of retrieval inhibition being greater for threatening than non-threatening categories. The data are in line with the avoidance aspect of the vigilance-avoidance theory of anxiety and inhibition. Implications for cognitive behavioural therapy practices are discussed.

Inhibition of adenovirus replication by a trisubstituted piperazin-2-one derivative.

PubMed

Sanchez-Cespedes, Javier; Moyer, Crystal L; Whitby, Landon R; Boger, Dale L; Nemerow, Glen R

2014-08-01

The number of disseminated adenovirus (Ad) infections continues to increase mostly due to the growing use of immunosuppressive treatments. Recipients of solid organ or hematopoietic stem cell transplants, mainly in pediatric units, exhibit a high morbidity and mortality due to these infections. Unfortunately, there are no Ad-specific antiviral drugs currently approved for medical use. To address this situation, we used high-throughput screening (HTS) of synthetic small molecule libraries to identify compounds that restrict Ad infection. Among the more than 25,000 compounds screened, we identified a hit compound that significantly inhibited Ad infection. The compound (15D8) is a trisubstituted piperazin-2-one derivative that showed substantial antiviral activity with little or no cytotoxicity at low micromolar concentrations. Compound 15D8 selectively inhibits Ad DNA replication in the nucleus, providing a potential candidate for the development of a new class of antiviral compounds to treat Ad infections. Copyright © 2014 Elsevier B.V. All rights reserved.

Solid - solid and solid - liquid phase transitions of iron and iron alloys under laser shock compression

NASA Astrophysics Data System (ADS)

Harmand, M.; Krygier, A.; Appel, K.; Galtier, E.; Hartley, N.; Konopkova, Z.; Lee, H. J.; McBride, E. E.; Miyanishi, K.; Nagler, B.; Nemausat, R.; Vinci, T.; Zhu, D.; Ozaki, N.; Fiquet, G.

2017-12-01

An accurate knowledge of the properties of iron and iron alloys at high pressures and temperatures is crucial for understanding and modelling planetary interiors. While Earth-size and Super-Earth Exoplanets are being discovered in increasingly large numbers, access to detailed information on liquid properties, melting curves and even solid phases of iron and iron at the pressures and temperatures of their interiors is still strongly limited. In this context, XFEL sources coupled with high-energy lasers afford unique opportunities to measure microscopic structural properties at far extreme conditions. Also the achievable time resolution allows the shock history and phase transition mechanisms to be followed during laser compression, improving our understanding of the high pressure and high strain experiments. Here we present recent studies devoted to investigate the solid-solid and solid-liquid transition in laser-shocked iron and iron alloys (Fe-Si, Fe-C and Fe-O alloys) using X-ray diffraction and X-ray diffuse scattering. Experiment were performed at the MEC end-station of the LCLS facility at SLAC (USA). Detection of the diffuse scattering allowed the identification of the first liquid peak position along the Hugoniot, up to 4 Mbar. The time resolution shows ultrafast (between several tens and several hundreds of picoseconds) solid-solid and solid-liquid phase transitions. Future developments at XFEL facilities will enable detailed studies of the solid and liquid structures of iron and iron alloys as well as out-of-Hugoniot studies.

FAK Inhibition Decreases Hepatoblastoma Survival Both In Vitro and In Vivo12

PubMed Central

Gillory, Lauren A; Stewart, Jerry E; Megison, Michael L; Nabers, Hugh C; Mroczek-Musulman, Elizabeth; Beierle, Elizabeth A

2013-01-01

Hepatoblastoma is the most frequently diagnosed liver tumor of childhood, and children with advanced, metastatic or relapsed disease have a disease-free survival rate under 50%. Focal adhesion kinase (FAK) is a nonreceptor tyrosine kinase that is important in many facets of tumor development and progression. FAK has been found in other pediatric solid tumors and in adult hepatocellular carcinoma, leading us to hypothesize that FAK would be present in hepatoblastoma and would impact its cellular survival. In the current study, we showed that FAK was present and phosphorylated in human hepatoblastoma tumor specimens. We also examined the effects of FAK inhibition upon hepatoblastoma cells using a number of parallel approaches to block FAK including RNAi and small molecule FAK inhibitors. FAK inhibition resulted in decreased cellular survival, invasion, and migration and increased apoptosis. Further, small molecule inhibition of FAK led to decreased tumor growth in a nude mouse xenograft model of hepatoblastoma. The findings from this study will help to further our understanding of the regulation of hepatoblastoma tumorigenesis and may provide desperately needed novel therapeutic strategies and targets for aggressive, recurrent, or metastatic hepatoblastomas. PMID:23544173

Inhibition.

ERIC Educational Resources Information Center

Kupperman, Joel J.

1978-01-01

Explores the use of the concept of inhibition in moral philosophy. Argues that there are strong practical reasons for basing moral teaching on simple moral rules and for inculcating inhibitions about breaking these rules. (Author)

Assessment of solid microneedle rollers to enhance transmembrane delivery of doxycycline and inhibition of MMP activity.

PubMed

Omolu, Abbie; Bailly, Maryse; Day, Richard M

2017-11-01

Many chronic wounds exhibit high matrix metalloproteinase (MMP) activity that impedes the normal wound healing process. Intradermal delivery (IDD) of sub-antimicrobial concentrations of doxycycline, as an MMP inhibitor, could target early stages of chronic wound development and inhibit further wound progression. To deliver doxycycline intradermally, the skin barrier must be disrupted. Microneedle rollers offer a minimally invasive technique to penetrate the skin by creating multiple microchannels that act as temporary conduits for drugs to diffuse through. In this study, an innovative and facile approach for delivery of doxycycline across Strat-M TM membrane was investigated using microneedle rollers. The quantity and rate of doxycycline diffusing through the micropores directly correlated with increasing microneedle lengths (250, 500 and 750 μm). Treatment of Strat-M TM with microneedle rollers resulted in a reduction in fibroblast-mediated collagen gel contraction and MMP activity compared with untreated Strat-M TM . Our results show that treatment of an epidermal mimetic with microneedle rollers provides sufficient permeabilization for doxycycline diffusion and inhibition of MMP activity. We conclude that microneedle rollers are a promising, clinically ready tool suitable for delivery of doxycycline intradermally to treat chronic wounds.

Effective aqueous arsenic removal using zero valent iron doped MWCNT synthesized by in situ CVD method using natural α-Fe2O3 as a precursor.

PubMed

Alijani, Hassan; Shariatinia, Zahra

2017-03-01

This research presents an efficient system for removing aqua's arsenic based on in situ zero valent iron doping onto multiwall carbon nanotube (MWCNT) through MWCNT growth onto the natural α-Fe 2 O 3 surface in chemical vapor deposition (CVD) reactor. The as-synthesized magnetic nanohybrid was characterized by XRD, VSM, FE-SEM and TEM techniques. The result of XRD analysis revealed that MWCNT has been successfully generated on the surface of zero valent iron. Moreover, the material showed good superparamagnetic characteristic to be employed as a magnetic adsorbent. The hematite, nanohybrid and its air oxidized form were used for removing aqueous arsenite and arsenate; however, non oxidized material exhibited greater efficiency for the analytes uptake. Equilibrium times were 60 and 90 min for arsenate and arsenite adsorption using nanohybrid and oxidized sorbent but the equilibrium time was 1320 min using hematite. The adsorption efficiencies of hematite and oxidized sorbent were 18, 74% and 26, 77% for arsenite and arsenate, respectively, at initial concentration of 10 mg L -1 . At this situation, the removal efficiencies were 96 and 98.5% for arsenite and arsenate adsorption using raw nanohybrid. Thermodynamic study was also performed and results indicated that arsenic adsorption onto nanohybrid and oxidized sorbent was spontaneous however hematite followed a nonspontaneous path for the arsenic removal. Copyright © 2016 Elsevier Ltd. All rights reserved.

Edge-on and face-on functionalized Pc on enriched semiconducting SWCNT hybrids.

PubMed

Arellano, Luis M; Martín-Gomis, Luis; Gobeze, Habtom B; Molina, Desiré; Hermosa, Cristina; Gómez-Escalonilla, María J; Fierro, José Luis G; Sastre-Santos, Ángela; D'Souza, Francis; Langa, Fernando

2018-03-15

Enriched semiconducting single-walled carbon nanotubes (SWCNT (6,5) and SWCNT (7,6)) and HiPco nanotubes were covalently functionalized with either zinc phthalocyanine or silicon phthalocyanine as electron donors. The synthetic strategy resulted in edge-on and face-on geometries with respect to the phthalocyanine geometry, with both phthalocyanines held by an electronically conducting diphenylacetylene linker. The extent of functionalization in the MPc-SWCNT (M = Zn or Si) donor-acceptor nanohybrids was determined by systematic studies involving AFM, TGA, XPS, optical and Raman techniques. Intramolecular interactions in MPc-SWCNT nanohybrids were probed by studies involving optical absorbance, Raman, luminescence and electrochemical studies. Different degrees of interactions were observed depending on the type of MPc and mode of attachment. Substantial quenching of MPc fluorescence in these hybrids was observed from steady-state and three-dimensional fluorescence mapping, which suggests the occurrence of excited state events. Evidence for the occurrence of excited state charge transfer type interactions was subsequently secured from femtosecond transient absorption studies covering both the visible and near-infrared regions. Furthermore, electron-pooling experiments performed in the presence of a sacrificial electron donor and a second electron acceptor revealed accumulation of one-electron reduced product upon continuous irradiation of the nanohybrids. In such experiments, the ZnPc-SWCNT (6,5) nanohybrid outperformed other nanohybrids and this suggests that this is a superior donor-acceptor system for photocatalytic applications.

Shock wave as a probe of flux-dimited thermal transport in laser-heated solids

NASA Astrophysics Data System (ADS)

Smith, K.; Forsman, A.; Chiu, G.

1996-11-01

Laser-generated shock waves in solids result from the ablation of the target material. Where radiation transport is negligible, the ablation process is dominated by electron thermal conduction. This offers an opportunity to probe the degree of transport inhibition (compared with classical heat flow) for steep temperature gradients in a dense plasma. Using a 1-dimensional hydrodynamic code, we have examined the effect of flux-limited thermal conduction on the amplitude of the resulting shock wave.

Shear Bond Strength of Composite and Ceromer Superstructures to Direct Laser Sintered and Ni-Cr-Based Infrastructures Treated with KTP, Nd:YAG, and Er:YAG Lasers: An Experimental Study.

PubMed

Gorler, Oguzhan; Hubbezoglu, Ihsan; Ulgey, Melih; Zan, Recai; Guner, Kubra

2018-04-01

The aim of this study was to examine the shear bond strength (SBS) of ceromer and nanohybrid composite to direct laser sintered (DLS) Cr-Co and Ni-Cr-based metal infrastructures treated with erbium-doped yttrium aluminum garnet (Er:YAG), neodymium-doped yttrium aluminum garnet (Nd:YAG), and potassium titanyl phosphate (KTP) laser modalities in in vitro settings. Experimental specimens had four sets (n = 32) including two DLS infrastructures with ceromer and nanohybrid composite superstructures and two Ni-Cr-based infrastructures with ceromer and nanohybrid composite superstructures. Of each infrastructure set, the specimens randomized into four treatment modalities (n = 8): no treatment (controls) and Er:YAG, Nd:YAG, and KTP lasers. The infrastructures were prepared in the final dimensions of 7 × 3 mm. Ceromer and nanohybrid composite was applied to the infrastructures after their surface treatments according to randomization. The SBS of specimens was measured to test the efficacy of surface treatments. Representative scanning electron microscopy (SEM) images after laser treatments were obtained. Overall, in current experimental settings, Nd:YAG, KTP, and Er:YAG lasers, in order of efficacy, are effective to improve the bonding of ceromer and nanohybrid composite to the DLS and Ni-Cr-based infrastructures (p < 0.05). Nd:YAG laser is more effective in the DLS/ceromer infrastructures (p < 0.05). KTP laser, as second more effective preparation, is more effective in the DLS/ceromer infrastructures (p < 0.05). SEM findings presented moderate accordance with these findings. The results of this study supported the bonding of ceromer and nanohybrid composite superstructures to the DLS and Ni-Cr-based infrastructures suggesting that laser modalities, in order of success, Nd:YAG, KTP, and Er:YAG, are effective to increase bonding of these structures.

Pectins filled with LDH-antimicrobial molecules: preparation, characterization and physical properties.

PubMed

Gorrasi, Giuliana; Bugatti, Valeria; Vittoria, Vittoria

2012-06-05

Nanohybrids of layered double hydroxide (LDH) with intercalated active molecules: benzoate, 2,4-dichlorobenzoate, para-hydroxybenzoate and ortho-hydroxybenzoate, were incorporated into pectins from apples through high energy ball milling in the presence of water. Cast films were obtained and analysed. X-ray diffraction analysis showed a complete destructuration of all nanohybrids in the pectin matrix. Thermogravimetric analysis showed a better thermal resistance of pectin in the presence of fillers, especially para-hydroxybenzoate and ortho-hydroxybenzoate. Mechanical properties showed an improvement of elastic modulus in particular for LDH-para-hydroxybenzoate nanohybrid, due probably to a better interaction between pectin matrix and nanohybrid layers. Barrier properties (sorption and diffusion) to water vapour showed improvement in the dependence on the intercalated active molecule, the best improvement was achieved for composites containing para-hydroxybenzoate molecules, suggesting that the interaction between the filler phase and the polymer plays an important role in sorption and diffusion phenomena. Incorporation of these active molecules gave antimicrobial properties to the composite films giving opportunities in the field of active packaging. Copyright © 2012 Elsevier Ltd. All rights reserved.

Shikonin suppresses proliferation and induces cell cycle arrest through the inhibition of hypoxia-inducible factor-1α signaling.

PubMed

Li, Ming Yue; Mi, Chunliu; Wang, Ke Si; Wang, Zhe; Zuo, Hong Xiang; Piao, Lian Xun; Xu, Guang Hua; Li, Xuezheng; Ma, Juan; Jin, Xuejun

2017-08-25

Hypoxia enhances the development of solid tumors. Hypoxia-inducible factor-1α (HIF-1α) is a transcription factor that is dominantly expressed under hypoxia in solid tumor cells and is a key factor of tumor regulation. HIF-1α regulates several target genes involved in many aspects of cancer progression, including angiogenesis, metastasis, and cell proliferation, as well as imparting resistance to cancer treatment. In this study, we assessed shikonin, which derives from the traditional medical herb Lithospermum erythrorhizon, for its anti-cancer effects in hypoxia-induced human colon cancer cell lines. Shikonin showed potent inhibitory activity against hypoxia-induced HIF-1α activation in various human cancer cell lines and efficient scavenging activity of hypoxia-induced reactive oxygen species in tumor cells. Further analysis revealed that shikonin inhibited HIF-1α protein synthesis without affecting the expression of HIF-1α mRNA or degrading HIF-1α protein. It was subsequently shown to attenuate the activation of downstream mTOR/p70S6K/4E-BP1/eIF4E kinase. Shikonin also dose-dependently caused the cell cycle arrest of activated HCT116 cells and inhibited the proliferation of HCT116 and SW620 cells. Moreover, it significantly inhibited tumor growth in a xenograft modal. These findings suggest that shikonin could be considered for use as a potential drug in human colon cancer therapy. Copyright © 2017 Elsevier B.V. All rights reserved.

History of Solid Rockets

NASA Technical Reports Server (NTRS)

Green, Rebecca

2017-01-01

Solid rockets are of interest to the space program because they are commonly used as boosters that provide the additional thrust needed for the space launch vehicle to escape the gravitational pull of the Earth. Larger, more advanced solid rockets allow for space launch vehicles with larger payload capacities, enabling mankind to reach new depths of space. This presentation will discuss, in detail, the history of solid rockets. The history begins with the invention and origin of the solid rocket, and then goes into the early uses and design of the solid rocket. The evolution of solid rockets is depicted by a description of how solid rockets changed and improved and how they were used throughout the 16th, 17th, 18th, and 19th centuries. Modern uses of the solid rocket include the Solid Rocket Boosters (SRBs) on the Space Shuttle and the solid rockets used on current space launch vehicles. The functions and design of the SRB and the advancements in solid rocket technology since the use of the SRB are discussed as well. Common failure modes and design difficulties are discussed as well.

Solid lubricants: A survey

NASA Technical Reports Server (NTRS)

Campbell, M. E.

1972-01-01

A survey is presented of the most recent developments and trends in the field of solid lubrication. Topics discussed include: a history of solid lubrication, lubricating solids, bonded lubricants, new developments, methods of evaluation, environmental effects, application methods, novel materials, and designs for the use of solid lubricants. Excerpts of solid lubricant specifications and a discussion of contact stresses imposed on specimens in three types of test machines used for the evaluation of solid lubricants are presented.

Innovative Delivery of siRNA to Solid Tumors by Super Carbonate Apatite

PubMed Central

Wu, Xin; Yamamoto, Hirofumi; Nakanishi, Hiroyuki; Yamamoto, Yuki; Inoue, Akira; Tei, Mitsuyoshi; Hirose, Hajime; Uemura, Mamoru; Nishimura, Junichi; Hata, Taishi; Takemasa, Ichiro; Mizushima, Tsunekazu; Hossain, Sharif; Akaike, Toshihiro; Matsuura, Nariaki; Doki, Yuichiro; Mori, Masaki

2015-01-01

RNA interference (RNAi) technology is currently being tested in clinical trials for a limited number of diseases. However, systemic delivery of small interfering RNA (siRNA) to solid tumors has not yet been achieved in clinics. Here, we introduce an in vivo pH-sensitive delivery system for siRNA using super carbonate apatite (sCA) nanoparticles, which is the smallest class of nanocarrier. These carriers consist simply of inorganic ions and accumulate specifically in tumors, yet they cause no serious adverse events in mice and monkeys. Intravenously administered sCA-siRNA abundantly accumulated in the cytoplasm of tumor cells at 4 h, indicating quick achievement of endosomal escape. sCA-survivin-siRNA induced apoptosis in HT29 tumors and significantly inhibited in vivo tumor growth of HCT116, to a greater extent than two other in vivo delivery reagents. With innovative in vivo delivery efficiency, sCA could be a useful nanoparticle for the therapy of solid tumors. PMID:25738937

Innovative delivery of siRNA to solid tumors by super carbonate apatite.

PubMed

Wu, Xin; Yamamoto, Hirofumi; Nakanishi, Hiroyuki; Yamamoto, Yuki; Inoue, Akira; Tei, Mitsuyoshi; Hirose, Hajime; Uemura, Mamoru; Nishimura, Junichi; Hata, Taishi; Takemasa, Ichiro; Mizushima, Tsunekazu; Hossain, Sharif; Akaike, Toshihiro; Matsuura, Nariaki; Doki, Yuichiro; Mori, Masaki

2015-01-01

RNA interference (RNAi) technology is currently being tested in clinical trials for a limited number of diseases. However, systemic delivery of small interfering RNA (siRNA) to solid tumors has not yet been achieved in clinics. Here, we introduce an in vivo pH-sensitive delivery system for siRNA using super carbonate apatite (sCA) nanoparticles, which is the smallest class of nanocarrier. These carriers consist simply of inorganic ions and accumulate specifically in tumors, yet they cause no serious adverse events in mice and monkeys. Intravenously administered sCA-siRNA abundantly accumulated in the cytoplasm of tumor cells at 4 h, indicating quick achievement of endosomal escape. sCA-survivin-siRNA induced apoptosis in HT29 tumors and significantly inhibited in vivo tumor growth of HCT116, to a greater extent than two other in vivo delivery reagents. With innovative in vivo delivery efficiency, sCA could be a useful nanoparticle for the therapy of solid tumors.

Copper binding by tetrathiomolybdate attenuates angiogenesis and tumor cell proliferation through the inhibition of superoxide dismutase 1.

PubMed

Juarez, Jose C; Betancourt, Oscar; Pirie-Shepherd, Steven R; Guan, Xiaojun; Price, Melissa L; Shaw, David E; Mazar, Andrew P; Doñate, Fernando

2006-08-15

A second-generation tetrathiomolybdate analogue (ATN-224; choline tetrathiomolybdate), which selectively binds copper with high affinity, is currently completing two phase I clinical trials in patients with advanced solid and advanced hematologic malignancies. However, there is very little information about the mechanism of action of ATN-224 at the molecular level. The effects of ATN-224 on endothelial and tumor cell growth were evaluated in cell culture experiments in vitro. The antiangiogenic activity of ATN-224 was investigated using the Matrigel plug model of angiogenesis. ATN-224 inhibits superoxide dismutase 1 (SOD1) in tumor and endothelial cells. The inhibition of SOD1 leads to inhibition of endothelial cell proliferation in vitro and attenuation of angiogenesis in vivo. The inhibition of SOD1 activity in endothelial cells is dose and time dependent and leads to an increase in the steady-state levels of superoxide anions, resulting in the inhibition of extracellular signal-regulated kinase phosphorylation without apparent induction of apoptosis. In contrast, the inhibition of SOD1 in tumor cells leads to the induction of apoptosis. The effects of ATN-224 on endothelial and tumor cells could be substantially reversed using Mn(III)tetrakis(4-benzoic acid)porphyrin chloride, a catalytic small-molecule SOD mimetic. These data provide a distinct molecular target for the activity of ATN-224 and provide validation for SOD1 as a target for the inhibition of angiogenesis and tumor growth.

Solid lubricants

NASA Technical Reports Server (NTRS)

Sliney, Harold E.

1991-01-01

The state of knowledge of solid lubricants is reviewed. The results of research on solid lubricants from the 1940's to the present are presented from a historical perspective. Emphasis is placed largely, but not exclusively, on work performed at NASA Lewis Research Center with a natural focus on aerospace applications. However, because of the generic nature of the research, the information presented in this review is applicable to most areas where solid lubricant technology is useful.

Optically active substituted polyacetylene@carbon nanotube hybrids: Preparation, characterization and infrared emissivity property study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bu, Xiaohai; Zhou, Yuming, E-mail: ymzhou@seu.edu.cn; Zhang, Tao

Optically active substituted polyacetylene@multiwalled carbon nanotubes (SPA@MWCNTs) nanohybrids were fabricated by wrapping helical SPA copolymers onto the surface of modified nanotubes through ester bonding linkage. SPA copolymer based on chiral phenylalanine and serine was pre-polymerized by a rhodium zwitterion catalyst in THF, and evidently proved to possess strong optical activity and adopt a predominately one-handed helical conformation. Various characterizations including Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and transmission electron microscopy (TEM) demonstrated that the SPA had been covalently grafted onto the nanotubes without destroying their original graphite structure. The wrapped SPA was found tomore » exhibit an enhancement in thermal stability and still maintained considerable optical activity after grafting. The infrared emissivity property of the nanohybrids at 8–14 μm was investigated in addition. The results indicated that the SPA@MWCNTs hybrid matrix could possess a much lower infrared emissivity value (ε=0.707) than raw MWCNTs, which might be due to synergistic effect of the unique helical conformation of optically active SPA and strengthened interfacial interaction between the organic polymers and inorganic nanoparticles. - Graphical abstract: Optically active SPA@MWCNTs nanohybrids with low infrared emissivity. - Highlights: • Synthesis of optically active SPA copolymer derived from serine and phenylalanine. • Preparation and characterization of optically active SPA@MWCNTs nanohybrids. • Application study of the SPA@MWCNTs nanohybrids (ε=0.707) in lowering the infrared emissivity.« less

Executive and motivational inhibition: associations with self-report measures related to inhibition.

PubMed

Shuster, Jill; Toplak, Maggie E

2009-06-01

Inhibition involves the withholding or suppressing of attention or responses to irrelevant or distracting stimuli. We examined the relationship between five experimental tasks of inhibition, represented by two measures of executive, intentional control inhibition and three measures of motivational inhibition characterized by bottom-up interruption of affective and reward/punishment sensitive mechanisms. Associations between these experimental tasks with three self-report measures related to inhibition were also examined. Correlational analyses indicated a small but significant association between the measures in the executive domain (stop task and Stroop task), but a lack of associations between the measures in the motivational domain (emotional Stroop task, a card playing task involving rewards and punishments, and a gambling task). Both measures of executive and motivational inhibition entered as significant predictors on the self-report measures related to inhibition in simultaneous regression analyses, but not consistently in the expected direction. The results suggest that inhibition is not a unitary construct, and demonstrate an association between experimental measures of inhibition and self-report measures related to inhibition.

Ibrutinib Inhibits ERBB Receptor Tyrosine Kinases and HER2-Amplified Breast Cancer Cell Growth.

PubMed

Chen, Jun; Kinoshita, Taisei; Sukbuntherng, Juthamas; Chang, Betty Y; Elias, Laurence

2016-12-01

Ibrutinib is a potent, small-molecule Bruton tyrosine kinase (BTK) inhibitor developed for the treatment of B-cell malignancies. Ibrutinib covalently binds to Cys481 in the ATP-binding domain of BTK. This cysteine residue is conserved among 9 other tyrosine kinases, including HER2 and EGFR, which can be targeted. Screening large panels of cell lines demonstrated that ibrutinib was growth inhibitory against some solid tumor cells, including those inhibited by other HER2/EGFR inhibitors. Among sensitive cell lines, breast cancer lines with HER2 overexpression were most potently inhibited by ibrutinib (<100 nmol/L); in addition, the IC 50 s were lower than that of lapatinib and dacomitinib. Inhibition of cell growth by ibrutinib coincided with downregulation of phosphorylation on HER2 and EGFR and their downstream targets, AKT and ERK. Irreversible inhibition of HER2 and EGFR in breast cancer cells was established after 30-minute incubation above 100 nmol/L or following 2-hour incubation at lower concentrations. Furthermore, ibrutinib inhibited recombinant HER2 and EGFR activity that was resistant to dialysis and rapid dilution, suggesting an irreversible interaction. The dual activity toward TEC family (BTK and ITK) and ERBB family kinases was unique to ibrutinib, as ERBB inhibitors do not inhibit or covalently bind BTK or ITK. Xenograft studies with HER2 + MDA-MB-453 and BT-474 cells in mice in conjunction with determination of pharmacokinetics demonstrated significant exposure-dependent inhibition of growth and key signaling molecules at levels that are clinically achievable. Ibrutinib's unique dual spectrum of activity against both TEC family and ERBB kinases suggests broader applications of ibrutinib in oncology. Mol Cancer Ther; 15(12); 2835-44. ©2016 AACR. ©2016 American Association for Cancer Research.

Long chain fatty acids (LCFA) evolution for inhibition forecasting during anaerobic treatment of lipid-rich wastes: Case of milk-fed veal slaughterhouse waste.

PubMed

Rodríguez-Méndez, R; Le Bihan, Y; Béline, F; Lessard, P

2017-09-01

A detailed study of a solid slaughterhouse waste (SHW) anaerobic treatment is presented. The waste used in this study is rich in lipids and proteins residue. Long chain fatty acids (LCFA), coming from the hydrolysis of lipids were inhibitory to anaerobic processes at different degrees. Acetogenesis and methanogenesis processes were mainly affected by inhibition whereas disintegration and hydrolysis processes did not seem to be affected by high LCFA concentrations. Nevertheless, because of the high energy content, this kind of waste is very suitable for anaerobic digestion but strict control of operating conditions is required to prevent inhibition. For that, two inhibition indicators were identified in this study. Those two indicators, LCFA dynamics and LCFA/VS biomass ratio proved to be useful to predict and to estimate the process inhibition degree. Copyright © 2017 Elsevier Ltd. All rights reserved.

General view of the Solid Rocket Booster's (SRB) Solid Rocket ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

General view of the Solid Rocket Booster's (SRB) Solid Rocket Motor Segments in the Surge Building of the Rotation Processing and Surge Facility at Kennedy Space Center awaiting transfer to the Vehicle Assembly Building and subsequent mounting and assembly on the Mobile Launch Platform. - Space Transportation System, Solid Rocket Boosters, Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX

Background distraction during vertical solid and character line bisections.

PubMed

Rodriguez, Julio A; Lamb, Damon G; Salazar, Liliana; Correa, Lauren N; Mosquera, Diana M; Schwartz, Zared J; Cohen, Ronald A; Falchook, Adam D; Heilman, Kenneth M

2018-04-04

Background-objectives: When vertical lines are positioned above or below the center of the page, line bisection deviates toward the center of the page, suggesting that the edges of the page distract the allocation of attention to the line. A letter-character line (LCL) bisection requires both global and focal attention, to identify the target letter closest to the line's center. If more focal and less global attention is allocated to a LCL, more global attentional resources may be available and inadvertently allocated to the page. Alternatively, if the allocation of focal attention to a LCL inhibits global attentional processing, there may be less distraction by the page. Twenty-four healthy adults (12 older) bisected vertical solid and character lines centered, or positioned closer to the top or bottom of the page. There was no difference between bisection of solid and character lines centered on the page. Page-related deviations were greater with character lines than solid line bisections, and greater for lines positioned toward the top than the bottom of the page. With lines positioned toward the top, the older participants' attempted bisections were higher than those of the younger participants. These results suggest that the allocation of focal attention increases global attentional distractibility and that global-background attentional distraction is greater when the vertical lines are placed in the upper part of the page. Older participants appeared to be less distracted when lines were placed toward the top of the page, but the reason for this age difference requires further research.

Dual Tuning of Biomass-Derived Hierarchical Carbon Nanostructures for Supercapacitors: the Role of Balanced Meso/Microporosity and Graphene.

PubMed

Zhu, Zhengju; Jiang, Hao; Guo, Shaojun; Cheng, Qilin; Hu, Yanjie; Li, Chunzhong

2015-10-30

Rational design of advanced carbon nanomaterials with a balanced mesoporosity to microporosity is highly desirable for achieving high energy/power density for supercapacitors because the mesopore can allow better transport pathways for the solvated ions of larger than 1 nm. Inspired by the inherent meso/macroporous architecture and huge absorption ability to aqueous solution of auricularia biomass, we demonstrate a new biomass-derived synthesis process for the three-dimensional (3D) few-layered graphene nanosheets incorporated hierarchical porous carbon (GHPC) nanohybrids. The as-prepared GHPC nanohybrids possess a balanced mesoporosity to microporosity with much improved conductivity, which is highly desirable for achieving high energy/power density for supercapacitors. As we predicted, they delivered a high specific capacitance of 256 F g(-1) at 1 A g(-1) with excellent rate capability (120 F g(-1) at 50 A g(-1)) and long cycle life (92% capacity retention after 10000 cycles) for symmetric supercapacitors in 1 M H2SO4. Based on the as-obtained carbon materials, a flexible and all-solid-state supercapacitor was also assembled, which can be fully recharged within 10 s and able to light an LED even under bended state. Such excellent performance is at least comparable to the best reports in the literature for two-electrode configuration under aqueous systems.

Dual Tuning of Biomass-Derived Hierarchical Carbon Nanostructures for Supercapacitors: the Role of Balanced Meso/Microporosity and Graphene

NASA Astrophysics Data System (ADS)

Zhu, Zhengju; Jiang, Hao; Guo, Shaojun; Cheng, Qilin; Hu, Yanjie; Li, Chunzhong

2015-10-01

Rational design of advanced carbon nanomaterials with a balanced mesoporosity to microporosity is highly desirable for achieving high energy/power density for supercapacitors because the mesopore can allow better transport pathways for the solvated ions of larger than 1 nm. Inspired by the inherent meso/macroporous architecture and huge absorption ability to aqueous solution of auricularia biomass, we demonstrate a new biomass-derived synthesis process for the three-dimensional (3D) few-layered graphene nanosheets incorporated hierarchical porous carbon (GHPC) nanohybrids. The as-prepared GHPC nanohybrids possess a balanced mesoporosity to microporosity with much improved conductivity, which is highly desirable for achieving high energy/power density for supercapacitors. As we predicted, they delivered a high specific capacitance of 256 F g-1 at 1 A g-1 with excellent rate capability (120 F g-1 at 50 A g-1) and long cycle life (92% capacity retention after 10000 cycles) for symmetric supercapacitors in 1 M H2SO4. Based on the as-obtained carbon materials, a flexible and all-solid-state supercapacitor was also assembled, which can be fully recharged within 10 s and able to light an LED even under bended state. Such excellent performance is at least comparable to the best reports in the literature for two-electrode configuration under aqueous systems.

Dual Tuning of Biomass-Derived Hierarchical Carbon Nanostructures for Supercapacitors: the Role of Balanced Meso/Microporosity and Graphene

PubMed Central

Zhu, Zhengju; Jiang, Hao; Guo, Shaojun; Cheng, Qilin; Hu, Yanjie; Li, Chunzhong

2015-01-01

Rational design of advanced carbon nanomaterials with a balanced mesoporosity to microporosity is highly desirable for achieving high energy/power density for supercapacitors because the mesopore can allow better transport pathways for the solvated ions of larger than 1 nm. Inspired by the inherent meso/macroporous architecture and huge absorption ability to aqueous solution of auricularia biomass, we demonstrate a new biomass-derived synthesis process for the three-dimensional (3D) few-layered graphene nanosheets incorporated hierarchical porous carbon (GHPC) nanohybrids. The as-prepared GHPC nanohybrids possess a balanced mesoporosity to microporosity with much improved conductivity, which is highly desirable for achieving high energy/power density for supercapacitors. As we predicted, they delivered a high specific capacitance of 256 F g−1 at 1 A g−1 with excellent rate capability (120 F g−1 at 50 A g−1) and long cycle life (92% capacity retention after 10000 cycles) for symmetric supercapacitors in 1 M H2SO4. Based on the as-obtained carbon materials, a flexible and all-solid-state supercapacitor was also assembled, which can be fully recharged within 10 s and able to light an LED even under bended state. Such excellent performance is at least comparable to the best reports in the literature for two-electrode configuration under aqueous systems. PMID:26515442

The behavior of compression and degradation for municipal solid waste and combined settlement calculation method.

PubMed

Shi, Jianyong; Qian, Xuede; Liu, Xiaodong; Sun, Long; Liao, Zhiqiang

2016-09-01

The total compression of municipal solid waste (MSW) consists of primary, secondary, and decomposition compressions. It is usually difficult to distinguish between the three parts of compressions. In this study, the odeometer test was used to distinguish between the primary and secondary compressions to determine the primary and secondary compression coefficient. In addition, the ending time of the primary compressions were proposed based on municipal solid waste compression tests in a degradation-inhibited condition by adding vinegar. The amount of the secondary compression occurring in the primary compression stage has a relatively high percentage to either the total compression or the total secondary compression. The relationship between the degradation ratio and time was obtained from the tests independently. Furthermore, a combined compression calculation method of municipal solid waste for all three parts of compressions including considering organics degradation is proposed based on a one-dimensional compression method. The relationship between the methane generation potential L0 of LandGEM model and degradation compression index was also discussed in the paper. A special column compression apparatus system, which can be used to simulate the whole compression process of municipal solid waste in China, was designed. According to the results obtained from 197-day column compression test, the new combined calculation method for municipal solid waste compression was analyzed. The degradation compression is the main part of the compression of MSW in the medium test period. Copyright © 2015 Elsevier Ltd. All rights reserved.

Bicarbonate Increases Tumor pH and Inhibits Spontaneous Metastases

PubMed Central

Robey, Ian F.; Baggett, Brenda K.; Kirkpatrick, Nathaniel D.; Roe, Denise J.; Dosescu, Julie; Sloane, Bonnie F.; Hashim, Arig Ibrahim; Morse, David L.; Raghunand, Natarajan; Gatenby, Robert A.; Gillies, Robert J.

2010-01-01

The external pH of solid tumors is acidic as a consequence of increased metabolism of glucose and poor perfusion. Acid pH has been shown to stimulate tumor cell invasion and metastasis in vitro and in cells before tail vein injection in vivo. The present study investigates whether inhibition of this tumor acidity will reduce the incidence of in vivo metastases. Here, we show that oral NaHCO3 selectively increased the pH of tumors and reduced the formation of spontaneous metastases in mouse models of metastatic breast cancer. This treatment regimen was shown to significantly increase the extracellular pH, but not the intracellular pH, of tumors by 31P magnetic resonance spectroscopy and the export of acid from growing tumors by fluorescence microscopy of tumors grown in window chambers. NaHCO3 therapy also reduced the rate of lymph node involvement, yet did not affect the levels of circulating tumor cells, suggesting that reduced organ metastases were not due to increased intravasation. In contrast, NaHCO3 therapy significantly reduced the formation of hepatic metastases following intrasplenic injection, suggesting that it did inhibit extravasation and colonization. In tail vein injections of alternative cancer models, bicarbonate had mixed results, inhibiting the formation of metastases from PC3M prostate cancer cells, but not those of B16 melanoma. Although the mechanism of this therapy is not known with certainty, low pH was shown to increase the release of active cathepsin B, an important matrix remodeling protease. PMID:19276390

Solids mass flow determination

DOEpatents

Macko, Joseph E.

1981-01-01

Method and apparatus for determining the mass flow rate of solids mixed with a transport fluid to form a flowing mixture. A temperature differential is established between the solids and fluid. The temperature of the transport fluid prior to mixing, the temperature of the solids prior to mixing, and the equilibrium temperature of the mixture are monitored and correlated in a heat balance with the heat capacities of the solids and fluid to determine the solids mass flow rate.

Multivalent-Counterion-Induced Surfactant Multilayer Formation at Hydrophobic and Hydrophilic Solid-Solution Interfaces.

PubMed

Penfold, Jeffrey; Thomas, Robert K; Li, Peixun; Xu, Hui; Tucker, Ian M; Petkov, Jordan T; Sivia, Devinderjit S

2015-06-23

Surface multilayer formation from the anionic-nonionic surfactant mixture of sodium dodecyl dioxyethylene sulfate, SLES, and monododecyl dodecaethylene glycol, C12E12, by the addition of multivalent Al(3+) counterions at the solid-solution interface is observed and characterized by neutron reflectivity, NR. The ability to form surface multilayer structures on hydrophobic and hydrophilic silica and cellulose surfaces is demonstrated. The surface multilayer formation is more pronounced and more well developed on the hydrophilic and hydrophobic silica surfaces than on the hydrophilic and hydrophobic cellulose surfaces. The less well developed multilayer formation on the cellulose surfaces is attributed to the greater surface inhomogeneities of the cellulose surface which partially inhibit lateral coherence and growth of the multilayer domains at the surface. The surface multilayer formation is associated with extreme wetting properties and offers the potential for the manipulation of the solid surfaces for enhanced adsorption and control of the wetting behavior.

Characterisation of chamomile volatiles by simultaneous distillation solid-phase extraction in comparison to hydrodistillation and simultaneous distillation extraction.

PubMed

Krüger, Hans

2010-05-01

A new method for complete separation of steam-volatile organic compounds is described using the example of chamomile flowers. This method is based on the direct combination of hydrodistillation and solid-phase extraction in a circulation apparatus. In contrast to hydrodistillation and simultaneous distillation extraction (SDE), an RP-18 solid phase as adsorptive material is used rather than a water-insoluble solvent. Therefore, a prompt and complete fixation of all volatiles takes place, and the circulation of water-soluble bisabololoxides as well as water-soluble and thermolabile en-yne-spiroethers is inhibited. This so-called simultaneous distillation solid-phase extraction (SD-SPE) provides extracts that better characterise the real composition of the vapour phase, as well as the composition of inhalation vapours, than do SDE extracts or essential oils obtained by hydrodistillation. The data indicate that during inhalation therapy with chamomile, the bisabololoxides and spiroethers are more strongly involved in the inhaling activity than so far assumed. Georg Thieme Verlag KG Stuttgart New York.

Solid aerosol generator

DOEpatents

Prescott, Donald S.; Schober, Robert K.; Beller, John

1992-01-01

An improved solid aerosol generator used to produce a gas borne stream of dry, solid particles of predetermined size and concentration. The improved solid aerosol generator nebulizes a feed solution of known concentration with a flow of preheated gas and dries the resultant wet heated aerosol in a grounded, conical heating chamber, achieving high recovery and flow rates.

The use of solid lipid nanoparticles to target a lipophilic molecule to the liver after intravenous administration to mice.

PubMed

Lu, Wen; He, Lang Chong; Wang, Chang He; Li, Yan Hua; Zhang, San Qi

2008-10-01

Taspine solid lipid nanoparticles (Ta-SLN) and taspine solid lipid nanoparticles modified by galactoside (Ta-G2SLN) were prepared by the film evaporation-extrusion method. The nanoparticles were spherical or near-spherical particles with smooth surface, small size and high encapsulation efficiency. Ta-G2SLN and Ta-SLN showed significant inhibition on 7721 cell growth. Intravenous injection of either Ta-SLN or Ta-G2SLN resulted in a higher plasma and liver concentration and a longer retention time in mice compared with the administration of Ta. These results suggested that SLN tended to be preferentially delivered to the liver and Ta-G2SLN may further enhance liver targeting.

Current status of solid-state lithium batteries employing solid redox polymerization cathodes

NASA Astrophysics Data System (ADS)

Visco, S. J.; Doeff, M. M.; Dejonghe, L. C.

1991-03-01

The rapidly growing demand for secondary batteries having high specific energy and power has naturally led to increased efforts in lithium battery technology. Still, the increased safety risks associated with high energy density systems has tempered the enthusiasm of proponents of such systems for use in the consumer marketplace. The inherent advantages of all-solid-state batteries in regards to safety and reliability are strong factors in advocating their introduction to the marketplace. However, the low ionic conductivity of solid electrolytes relative to nonaqueous liquid electrolytes implies low power densities for solid state systems operating at ambient temperatures. Recent advances in polymer electrolytes have led to the introduction of solid electrolytes having conductivities in the range of 10(exp -4)/ohm cm at room temperature; this is still two orders of magnitude lower than liquid electrolytes. Although these improved ambient conductivities put solid state batteries in the realm of practical devices, it is clear that solid state batteries using such polymeric separators will be thin film devices. Fortunately, thin film fabrication techniques are well established in the plastics and paper industry, and present the possibility of continuous web-form manufacturing. This style of battery manufacture should make solid polymer batteries very cost-competitive with conventional secondary cells. In addition, the greater geometric flexibility of thin film solid state cells should provide benefits in terms of the end-use form factor in device design. This work discusses the status of solid redox polymerization cathodes.

Methods for the preparation and analysis of solids and suspended solids for methylmercury

USGS Publications Warehouse

DeWild, John F.; Olund, Shane D.; Olson, Mark L.; Tate, Michael T.

2004-01-01

This report presents the methods and method performance data for the determination of methylmercury concentrations in solids and suspended solids. Using the methods outlined here, the U.S. Geological Survey's Wisconsin District Mercury Laboratory can consistently detect methylmercury in solids and suspended solids at environmentally relevant concentrations. Solids can be analyzed wet or freeze dried with a minimum detection limit of 0.08 ng/g (as-processed). Suspended solids must first be isolated from aqueous matrices by filtration. The minimum detection limit for suspended solids is 0.01 ng per filter resulting in a minimum reporting limit ranging from 0.2 ng/L for a 0.05 L filtered volume to 0.01 ng/L for a 1.0 L filtered volume. Maximum concentrations for both matrices can be extended to cover nearly any amount of methylmercury by limiting sample size.

A Novel Type of Aqueous Dispersible Ultrathin-Layered Double Hydroxide Nanosheets for in Vivo Bioimaging and Drug Delivery.

PubMed

Yan, Li; Zhou, Mengjiao; Zhang, Xiujuan; Huang, Longbiao; Chen, Wei; Roy, Vellaisamy A L; Zhang, Wenjun; Chen, Xianfeng

2017-10-04

Layered double hydroxide (LDH) nanoparticles have been widely used for various biomedical applications. However, because of the difficulty of surface functionalization of LDH nanoparticles, the systemic administration of these nanomaterials for in vivo therapy remains a bottleneck. In this work, we develop a novel type of aqueous dispersible two-dimensional ultrathin LDH nanosheets with a size of about 50 nm and a thickness of about 1.4 to 4 nm. We are able to covalently attach positively charged rhodamine B fluorescent molecules to the nanosheets, and the nanohybrid retains strong fluorescence in liquid and even dry powder form. Therefore, it is available for bioimaging. Beyond this, it is convenient to modify the nanosheets with neutral poly(ethylene glycol) (PEG), so the nanohybrid is suitable for drug delivery through systemic administration. Indeed, in the test of using these nanostructures for delivery of a negatively charged anticancer drug, methotrexate (MTX), in a mouse model, dramatically improved therapeutic efficacy is achieved, indicated by the effective inhibition of tumor growth. Furthermore, our systematic in vivo safety investigation including measuring body weight, determining biodistribution in major organs, hematology analysis, blood biochemical assay, and hematoxylin and eosin stain demonstrates that the new material is biocompatible. Overall, this work represents a major development in the path of modifying functional LDH nanomaterials for clinical applications.

Inorganic Nanovehicle Targets Tumor in an Orthotopic Breast Cancer Model

NASA Astrophysics Data System (ADS)

Choi, Goeun; Kwon, Oh-Joon; Oh, Yeonji; Yun, Chae-Ok; Choy, Jin-Ho

2014-03-01

The clinical efficacy of conventional chemotherapeutic agent, methotrexate (MTX), can be limited by its very short plasma half-life, the drug resistance, and the high dosage required for cancer cell suppression. In this study, a new drug delivery system is proposed to overcome such limitations. To realize such a system, MTX was intercalated into layered double hydroxides (LDHs), inorganic drug delivery vehicle, through a co-precipitation route to produce a MTX-LDH nanohybrid with an average particle size of approximately 130 nm. Biodistribution studies in mice bearing orthotopic human breast tumors revealed that the tumor-to-liver ratio of MTX in the MTX-LDH-treated-group was 6-fold higher than that of MTX-treated-one after drug treatment for 2 hr. Moreover, MTX-LDH exhibited superior targeting effect resulting in high antitumor efficacy inducing a 74.3% reduction in tumor volume compared to MTX alone, and as a consequence, significant survival benefits. Annexin-V and propidium iodine dual staining and TUNEL analysis showed that MTX-LDH induced a greater degree of apoptosis than free MTX. Taken together, our data demonstrate that a new MTX-LDH nanohybrid exhibits a superior efficacy profile and improved distribution compared to MTX alone and has the potential to enhance therapeutic efficacy via inhibition of tumor proliferation and induction of apoptosis.

Inorganic nanovehicle targets tumor in an orthotopic breast cancer model.

PubMed

Choi, Goeun; Kwon, Oh-Joon; Oh, Yeonji; Yun, Chae-Ok; Choy, Jin-Ho

2014-03-21

The clinical efficacy of conventional chemotherapeutic agent, methotrexate (MTX), can be limited by its very short plasma half-life, the drug resistance, and the high dosage required for cancer cell suppression. In this study, a new drug delivery system is proposed to overcome such limitations. To realize such a system, MTX was intercalated into layered double hydroxides (LDHs), inorganic drug delivery vehicle, through a co-precipitation route to produce a MTX-LDH nanohybrid with an average particle size of approximately 130 nm. Biodistribution studies in mice bearing orthotopic human breast tumors revealed that the tumor-to-liver ratio of MTX in the MTX-LDH-treated-group was 6-fold higher than that of MTX-treated-one after drug treatment for 2 hr. Moreover, MTX-LDH exhibited superior targeting effect resulting in high antitumor efficacy inducing a 74.3% reduction in tumor volume compared to MTX alone, and as a consequence, significant survival benefits. Annexin-V and propidium iodine dual staining and TUNEL analysis showed that MTX-LDH induced a greater degree of apoptosis than free MTX. Taken together, our data demonstrate that a new MTX-LDH nanohybrid exhibits a superior efficacy profile and improved distribution compared to MTX alone and has the potential to enhance therapeutic efficacy via inhibition of tumor proliferation and induction of apoptosis.

Polyphosphazene Solid Electrolytes.

DTIC Science & Technology

1984-10-01

soL..I’IIN ’ . LAV A - .:.u.s 009 ’-" 4. T .. T. edSutoe .TVCO EO T EI O Polyphosphazene Solid Electrolytes Interim Technical Repor 6. PEAFORMING RG ...Y. T.; Whitmore , D. H. Solid State Ionics 1982, 7, 129. (10) Bauerle, J. E. J. Phys. Chem. Solids 1969, 30, 2657. (11) MacDonald, J. R. J. Chem. Phys

Solid aerosol generator

DOEpatents

Prescott, D.S.; Schober, R.K.; Beller, J.

1992-03-17

An improved solid aerosol generator used to produce a gas borne stream of dry, solid particles of predetermined size and concentration is disclosed. The improved solid aerosol generator nebulizes a feed solution of known concentration with a flow of preheated gas and dries the resultant wet heated aerosol in a grounded, conical heating chamber, achieving high recovery and flow rates. 2 figs.

STAT3 Oligonucleotide Inhibits Tumor Angiogenesis in Preclinical Models of Squamous Cell Carcinoma

PubMed Central

Klein, Jonah D.; Sano, Daisuke; Sen, Malabika; Myers, Jeffrey N.; Grandis, Jennifer R.; Kim, Seungwon

2014-01-01

Purpose Signal transducer and activator of transcription 3 (STAT3) has shown to play a critical role in head and neck squamous cell carcinoma (HNSCC) and we have recently completed clinical trials of STAT3 decoy oligonucleotide in patients with recurrent or metastatic HNSCC. However, there is limited understanding of the role of STAT3 in modulating other aspects of tumorigenesis such as angiogenesis. In this study, we aimed to examine the effects of STAT3 decoy oligonucleotide on tumor angiogenesis. Experimental Design A STAT3 decoy oligonucleotide and small interfering RNA (siRNA) were used to inhibit STAT3 in endothelial cells in vitro and in vivo. The biochemical effects of STAT3 inhibition were examined in conjunction with the consequences on proliferation, migration, apoptotic staining, and tubule formation. Additionally, we assessed the effects of STAT3 inhibition on tumor angiogenesis using murine xenograft models. Results STAT3 decoy oligonucleotide decreased proliferation, induces apoptosis, decreased migration, and decreased tubule formation of endothelial cells in vitro. The STAT3 decoy oligonucleotide also inhibited tumor angiogenesis in murine tumor xenografts. Lastly, our data suggest that the antiangiogenic effects of STAT3 decoy oligonucleotide were mediatedthrough the inhibition of both STAT3 and STAT1. Conclusions The STAT3 decoy oligonucleotidewas found to be an effective antiangiogenic agent, which is likely to contribute to the overall antitumor effects of this agent in solid tumors.Taken together with the previously demonstrated antitumor activity of this agent, STAT3 decoy oligonucleotide represents a promising single agent approach to targeting both the tumor and vascular compartments in various malignancies. PMID:24404126

A novel and facile synthesis of carbon quantum dots via salep hydrothermal treatment as the silver nanoparticles support: Application to electroanalytical determination of H2O2 in fetal bovine serum.

PubMed

Jahanbakhshi, Mojtaba; Habibi, Biuck

2016-07-15

A simple, low-cost, and green process was used for the synthesis of carbon quantum dots (CQDs) through the hydrothermal treatment of salep as a novel bio-polymeric carbon source in presence of only pure water. The silver nanoparticles (AgNPs) were embedded on the surface of CQDs by ultra-violate (UV) irradiation to the CQDs and silver nitrate mixture solution. The as-synthesized CQDs and AgNPs decorated CQDs nanohybrid (AgNPs/CQDs) were characterized by UV-vis and photoluminescence spectroscopy, Fourier transform-infrared spectroscopy, transmission electron microscopy, atomic force microcopy, X-ray diffraction, and field emission scanning electron microscopy. Then, the AgNPs/CQDs nanohybrid was casted on the glassy carbon electrode in order to prepare an amperometric hydrogen peroxide (H2O2) sensor. The electrochemical investigations show that the AgNPs/CQDs nanohybrid possesses an excellent performance toward the H2O2 reduction. In the optimum condition, the linear range of H2O2 determination was achieved from 0.2 to 27.0μM with high sensitivity (1.5μA/µM) and the limit of detection was obtained about 80nM (S/N=3). Finally, the prepared nanohybrid modified electrode was effectively applied to the H2O2 detection in the disinfected fetal bovine serum samples, and the recovery was obtained about 98%. The achieved results indicate that the AgNPs/CQDs nanohybrid with high reproducibility, repeatability, and stability has a favorable capability in electrochemical sensors improvement. Copyright © 2016 Elsevier B.V. All rights reserved.

Isorhapontigenin induced cell growth inhibition and apoptosis by targeting EGFR-related pathways in prostate cancer.

PubMed

Zhu, Cuicui; Zhu, Qingyi; Wu, Zhaomeng; Yin, Yingying; Kang, Dan; Lu, Shan; Liu, Ping

2018-02-01

Isorhapontigenin (ISO), a naturally phytopolyphenol compound existing in Chinese herb, apples, and various vegetables, has attracted extensive interest in recent years for its diverse pharmacological characteristics. Increasing evidences reveal that ISO can inhibit cancer cell growth by induced apoptosis, however, the molecular mechanisms is not fully understood. In this study, we found for the first time that ISO apparently induced cell growth inhibition and apoptosis by targeting EGFR and its downstream signal pathways in prostate cancer (PCa) cells both in vitro and in vivo, whereas no obviously effect on normal prostate cells. From the results, we found that ISO competitively targeted EGFR with EGF and inhibited EGFR auto-phosphorylation, and then decreased the levels of p-Erk1/2, p-PI3 K, and p-AKT, and further induced down-regulation of p-FOXO1 and promoted FOXO1 nuclear translocation; and finally resulted in a significantly up-regulation of Bim/p21/27/Bax/cleaved Caspase-3/cleaved PARP-1 and a markedly down-regulation of Sp1/Bcl-2/XIAP/Cyclin D1. Moreover, our experimental data demonstrated that treatment of ISO decreased protein level of AR via both inhibiting the expression of AR gene and promoting the ubiquitination/degradation of AR proteins in proteasome. In vivo, we also found that ISO inhibited the growth of subcutaneous xenotransplanted tumor in nude mice by inducing PCa cell growth inhibition and apoptosis. Taken together, all findings here clearly implicated that EGFR-related signal pathways, including EGFR-PI3K-Akt and EGFR-Erk1/2 pathways, were involved in ISO-induced cell growth inhibition and apoptosis in PCa cells, providing a more solid theoretical basis for the application of ISO to treat patients with prostate cancer in clinic. © 2017 Wiley Periodicals, Inc.

Corroboration of naringin effects on the intestinal absorption and pharmacokinetic behavior of candesartan cilexetil solid dispersions using in-situ rat models.

PubMed

Surampalli, Gurunath; K Nanjwade, Basavaraj; Patil, P A

2015-01-01

The aim of this study was to corroborate the effects of naringin, a P-glycoprotein inhibitor, on the intestinal absorption and pharmacokinetics of candesartan (CDS) from candesartan cilexetil (CAN) solid dispersions using in-situ rat models. Intestinal transport and absorption studies were examined by in-situ single pass perfusion and closed-loop models. We evaluated the intestinal membrane damage in the presence of naringin by measuring the release of protein and alkaline phosphatase (ALP). We noticed 1.47-fold increase in Peff of CDS from freeze-dried CAN-loaded solid dispersions with naringin (15 mg/kg, w/w) when compared with freeze-dried solid dispersion without naringin using in-situ single pass intestinal perfusion model. However, no intestinal membrane damage was observed in the presence of naringin. Our findings from in-situ closed-loop pharmacokinetic studies showed 1.34-fold increase in AUC with elevated Cmax and shortened tmax for freeze-dried solid dispersion with naringin as compared to freeze-dried solid dispersion without naringin. This study demonstrated that increased solubilization (favored by freeze-dried solid dispersion) and efflux pump inhibition (using naringin), the relative bioavailability of CDS can be increased, suggesting an alternative potential for improving oral bioavailability of CAN.

Balanced feedforward inhibition and dominant recurrent inhibition in olfactory cortex

PubMed Central

Large, Adam M.; Vogler, Nathan W.; Mielo, Samantha; Oswald, Anne-Marie M.

2016-01-01

Throughout the brain, the recruitment of feedforward and recurrent inhibition shapes neural responses. However, disentangling the relative contributions of these often-overlapping cortical circuits is challenging. The piriform cortex provides an ideal system to address this issue because the interneurons responsible for feedforward and recurrent inhibition are anatomically segregated in layer (L) 1 and L2/3 respectively. Here we use a combination of optical and electrical activation of interneurons to profile the inhibitory input received by three classes of principal excitatory neuron in the anterior piriform cortex. In all classes, we find that L1 interneurons provide weaker inhibition than L2/3 interneurons. Nonetheless, feedforward inhibitory strength covaries with the amount of afferent excitation received by each class of principal neuron. In contrast, intracortical stimulation of L2/3 evokes strong inhibition that dominates recurrent excitation in all classes. Finally, we find that the relative contributions of feedforward and recurrent pathways differ between principal neuron classes. Specifically, L2 neurons receive more reliable afferent drive and less overall inhibition than L3 neurons. Alternatively, L3 neurons receive substantially more intracortical inhibition. These three features—balanced afferent drive, dominant recurrent inhibition, and differential recruitment by afferent vs. intracortical circuits, dependent on cell class—suggest mechanisms for olfactory processing that may extend to other sensory cortices. PMID:26858458

Effect of liquid-to-solid ratio on semi-solid Fenton process in hazardous solid waste detoxication.

PubMed

Hu, Li-Fang; Feng, Hua-Jun; Long, Yu-Yang; Zheng, Yuan-Ge; Fang, Cheng-Ran; Shen, Dong-Sheng

2011-01-01

The liquid-to-solid ratio (L/S) of semi-solid Fenton process (SSFP) designated for hazardous solid waste detoxication was investigated. The removal and minimization effects of o-nitroaniline (ONA) in simulate solid waste residue (SSWR) from organic arsenic industry was evaluated by total organic carbon (TOC) and ONA removal efficiency, respectively. Initially, Box-Behnken design (BBD) and response surface methodology (RSM) were used to optimize the key factors of SSFP. Results showed that the removal rates of TOC and ONA decreased as L/S increased. Subsequently, four target initial ONA concentrations including 100 mg kg(-1), 1 g kg(-1), 10 g kg(-1), and 100 gk g(-1) on a dry basis were evaluated for the effect of L/S. A significant cubic empirical model between the initial ONA concentration and L/S was successfully developed to predict the optimal L/S for given initial ONA concentration for SSFP. Moreover, an optimized operation strategy of multi-SSFP for different cases was determined based on the residual target pollutant concentration and the corresponding environmental conditions. It showed that the total L/S of multi-SSFP in all tested scenarios was no greater than 3.8, which is lower than the conventional slurry systems (L/S ≥ 5). The multi-SSFP is environment-friendly when it used for detoxication of hazardous solid waste contaminated by ONA and provides a potential method for the detoxication of hazardous solid waste contaminated by organics. Copyright © 2010 Elsevier Ltd. All rights reserved.

Compounds inhibiting the bioconversion of hydrothermally pretreated lignocellulose.

PubMed

Ko, Ja Kyong; Um, Youngsoon; Park, Yong-Cheol; Seo, Jin-Ho; Kim, Kyoung Heon

2015-05-01

Hydrothermal pretreatment using liquid hot water, steam explosion, or dilute acids enhances the enzymatic digestibility of cellulose by altering the chemical and/or physical structures of lignocellulosic biomass. However, compounds that inhibit both enzymes and microbial activity, including lignin-derived phenolics, soluble sugars, furan aldehydes, and weak acids, are also generated during pretreatment. Insoluble lignin, which predominantly remains within the pretreated solids, also acts as a significant inhibitor of cellulases during hydrolysis of cellulose. Exposed lignin, which is modified to be more recalcitrant to enzymes during pretreatment, adsorbs cellulase nonproductively and reduces the availability of active cellulase for hydrolysis of cellulose. Similarly, lignin-derived phenolics inhibit or deactivate cellulase and β-glucosidase via irreversible binding or precipitation. Meanwhile, the performance of fermenting microorganisms is negatively affected by phenolics, sugar degradation products, and weak acids. This review describes the current knowledge regarding the contributions of inhibitors present in whole pretreatment slurries to the enzymatic hydrolysis of cellulose and fermentation. Furthermore, we discuss various biological strategies to mitigate the effects of these inhibitors on enzymatic and microbial activity to improve the lignocellulose-to-biofuel process robustness. While the inhibitory effect of lignin on enzymes can be relieved through the use of lignin blockers and by genetically engineering the structure of lignin or of cellulase itself, soluble inhibitors, including phenolics, furan aldehydes, and weak acids, can be detoxified by microorganisms or laccase.

What Are Solid Fats?

MedlinePlus

... Menus Seasonal Winter Spring Summer Fall Food Waste Food Safety Newsroom Dietary ... Solid fats are fats that are solid at room temperature, like beef fat, butter, and shortening. Solid fats mainly come ...

A phase I/II study of carfilzomib 2-10-min infusion in patients with advanced solid tumors.

PubMed

Papadopoulos, Kyriakos P; Burris, Howard A; Gordon, Michael; Lee, Peter; Sausville, Edward A; Rosen, Peter J; Patnaik, Amita; Cutler, Richard E; Wang, Zhengping; Lee, Susan; Jones, Suzanne F; Infante, Jeffery R

2013-10-01

Tolerability, pharmacokinetics (PK), pharmacodynamics, and antitumor activity of carfilzomib, a selective proteasome inhibitor, administered twice weekly by 2-10-min intravenous (IV) infusion on days 1, 2, 8, 9, 15, and 16 in 28-day cycles, were assessed in patients with advanced solid tumors in this phase I/II study. Adult patients with solid tumors progressing after ≥1 prior therapies were enrolled. The dose was 20 mg/m(2) in week 1 of cycle 1 and 20, 27, or 36 mg/m(2) thereafter. The maximum tolerated dose or protocol-defined maximum planned dose (MPD) identified during dose escalation was administered to an expansion cohort and to patients with small cell lung, non-small cell lung, ovarian, and renal cancer in phase II tumor-specific cohorts. Fourteen patients received carfilzomib during dose escalation. The single dose-limiting toxicity at 20/36 mg/m(2) was grade 3 fatigue, establishing the MPD as the expansion and phase II dose. Sixty-five additional patients received carfilzomib at the MPD. Adverse events included fatigue, nausea, anorexia, and dyspnea. Carfilzomib PK was dose proportional with a half-life <1 h. All doses resulted in at least 80 % proteasome inhibition in blood. Partial responses occurred in two patients in phase I, with 21.5 % stable disease after four cycles in evaluable patients in the expansion and phase II cohorts. Carfilzomib 20/36 mg/m(2) was well tolerated when administered twice weekly by 2-10-min IV infusion. At this dose and infusion rate, carfilzomib inhibited the proteasome in blood but demonstrated limited antitumor activity in patients with advanced solid tumors.

Role of anisotropy in determining stability of electrodeposition at solid-solid interfaces

NASA Astrophysics Data System (ADS)

Ahmad, Zeeshan; Viswanathan, Venkatasubramanian

2017-10-01

We investigate the stability of electrodeposition at solid-solid interfaces for materials exhibiting an anisotropic mechanical response. The stability of electrodeposition or resistance to the formation of dendrites is studied within a linear stability analysis. The deformation and stress equations are solved using the Stroh formalism and faithfully recover the boundary conditions at the interface. The stability parameter is used to quantify the stability of different solid-solid interfaces incorporating the full anisotropy of the elastic tensor of the two materials. Results show a high degree of variability in the stability parameter depending on the crystallographic orientation of the solids in contact, and point to opportunities for exploiting this effect in developing Li metal anodes.

Biodegradable polymeric micelles encapsulated JK184 suppress tumor growth through inhibiting Hedgehog signaling pathway

NASA Astrophysics Data System (ADS)

Zhang, Nannan; Liu, Shichang; Wang, Ning; Deng, Senyi; Song, Linjiang; Wu, Qinjie; Liu, Lei; Su, Weijun; Wei, Yuquan; Xie, Yongmei; Gong, Changyang

2015-01-01

JK184 can specially inhibit Gli in the Hedgehog (Hh) pathway, which showed great promise for cancer therapeutics. For developing aqueous formulation and improving anti-tumor activity of JK184, we prepared JK184 encapsulated MPEG-PCL micelles by the solid dispersion method without using surfactants or toxic organic solvents. The cytotoxicity and cellular uptake of JK184 micelles were both increased compared with the free drug. JK184 micelles induced more apoptosis and blocked proliferation of Panc-1 and BxPC-3 tumor cells. In addition, JK184 micelles exerted a sustained in vitro release behavior and had a stronger inhibitory effect on proliferation, migration and invasion of HUVECs than free JK184. Furthermore, JK184 micelles had stronger tumor growth inhibiting effects in subcutaneous Panc-1 and BxPC-3 tumor models. Histological analysis showed that JK184 micelles improved anti-tumor activity by inducing more apoptosis, decreasing microvessel density and reducing expression of CD31, Ki67, and VEGF in tumor tissues. JK184 micelles showed a stronger inhibition of Gli expression in Hh signaling, which played an important role in pancreatic carcinoma. Furthermore, circulation time of JK184 in blood was prolonged after entrapment in polymeric micelles. Our results suggested that JK184 micelles are a promising drug candidate for treating pancreatic tumors with a highly inhibitory effect on Hh activity.JK184 can specially inhibit Gli in the Hedgehog (Hh) pathway, which showed great promise for cancer therapeutics. For developing aqueous formulation and improving anti-tumor activity of JK184, we prepared JK184 encapsulated MPEG-PCL micelles by the solid dispersion method without using surfactants or toxic organic solvents. The cytotoxicity and cellular uptake of JK184 micelles were both increased compared with the free drug. JK184 micelles induced more apoptosis and blocked proliferation of Panc-1 and BxPC-3 tumor cells. In addition, JK184 micelles exerted a sustained in

Solid electrolytes

DOEpatents

Abraham, Kuzhikalail M.; Alamgir, Mohamed

1993-06-15

This invention pertains to Li ion (Li.sup.+) conductive solid polymer electrolytes composed of solvates of Li salts immobilized (encapsulated) in a solid organic polymer matrix. In particular, this invention relates to solid polymer electrolytes derived by immobilizing complexes (solvates) formed between a Li salt such as LiAsF.sub.6, LiCF.sub.3 SO.sub.3 or LiClO.sub.4 and a mixture of aprotic organic solvents having high dielectric constants such as ethylene carbonate (EC) (dielectric constant=89.6) and propylene carbonate (PC) (dielectric constant=64.4) in a polymer matrix such as polyacrylonitrile, poly(tetraethylene glycol diacrylate), or poly(vinyl pyrrolidinone).

Solid expellant plasma generator

NASA Technical Reports Server (NTRS)

Stone, Nobie H. (Inventor); Poe, Garrett D. (Inventor); Rood, Robert (Inventor)

2010-01-01

An improved solid expellant plasma generator has been developed. The plasma generator includes a support housing, an electrode rod located in the central portion of the housing, and a mass of solid expellant material that surrounds the electrode rod within the support housing. The electrode rod and the solid expellant material are made of separate materials that are selected so that the electrode and the solid expellant material decompose at the same rate when the plasma generator is ignited. This maintains a point of discharge of the plasma at the interface between the electrode and the solid expellant material.

Simultaneous inhibition of aryl hydrocarbon receptor (AhR) and Src abolishes androgen receptor signaling.

PubMed

Ghotbaddini, Maryam; Cisse, Keyana; Carey, Alexis; Powell, Joann B

2017-01-01

Altered c-Src activity has been strongly implicated in the development, growth, progression, and metastasis of human cancers including prostate cancer. Src is known to regulate several biological functions of tumor cells, including proliferation. There are several Src inhibitors under evaluation for clinical effectiveness but have shown little activity in monotherapy trials of solid tumors. Combination studies are being explored by in vitro analysis and in clinical trials. Here we investigate the effect of simultaneous inhibition of the aryl hydrocarbon receptor (AhR) and Src on androgen receptor (AR) signaling in prostate cancer cells. AhR has also been reported to interact with the Src signaling pathway during prostate development. c-Src protein kinase is associated with the AhR complex in the cytosol and upon ligand binding to AhR, c-Src is activated and released from the complex. AhR has also been shown to regulate AR signaling which remains functionally important in the development and progression of prostate cancer. We provide evidence that co-inhibition of AhR and Src abolish AR activity. Evaluation of total protein and cellular fractions revealed decreased pAR expression and AR nuclear localization. Assays utilizing an androgen responsive element (ARE) and qRT-PCR analysis of AR genes revealed decreased AR promoter activity and transcriptional activity in the presence of both AhR and Src inhibitors. Furthermore, co-inhibition of AhR and Src reduced the growth of prostate cancer cells compared to individual treatments. Several studies have revealed that AhR and Src individually inhibit cellular proliferation. However, this study is the first to suggest simultaneous inhibition of AhR and Src to inhibit AR signaling and prostate cancer cell growth.

Solid-solid collapse transition in a two dimensional model molecular system.

PubMed

Singh, Rakesh S; Bagchi, Biman

2013-11-21

Solid-solid collapse transition in open framework structures is ubiquitous in nature. The real difficulty in understanding detailed microscopic aspects of such transitions in molecular systems arises from the interplay between different energy and length scales involved in molecular systems, often mediated through a solvent. In this work we employ Monte-Carlo simulation to study the collapse transition in a model molecular system interacting via both isotropic as well as anisotropic interactions having different length and energy scales. The model we use is known as Mercedes-Benz (MB), which, for a specific set of parameters, sustains two solid phases: honeycomb and oblique. In order to study the temperature induced collapse transition, we start with a metastable honeycomb solid and induce transition by increasing temperature. High density oblique solid so formed has two characteristic length scales corresponding to isotropic and anisotropic parts of interaction potential. Contrary to the common belief and classical nucleation theory, interestingly, we find linear strip-like nucleating clusters having significantly different order and average coordination number than the bulk stable phase. In the early stage of growth, the cluster grows as a linear strip, followed by branched and ring-like strips. The geometry of growing cluster is a consequence of the delicate balance between two types of interactions, which enables the dominance of stabilizing energy over destabilizing surface energy. The nucleus of stable oblique phase is wetted by intermediate order particles, which minimizes the surface free energy. In the case of pressure induced transition at low temperature the collapsed state is a disordered solid. The disordered solid phase has diverse local quasi-stable structures along with oblique-solid like domains.

Solid-solid collapse transition in a two dimensional model molecular system

NASA Astrophysics Data System (ADS)

Singh, Rakesh S.; Bagchi, Biman

2013-11-01

Solid-solid collapse transition in open framework structures is ubiquitous in nature. The real difficulty in understanding detailed microscopic aspects of such transitions in molecular systems arises from the interplay between different energy and length scales involved in molecular systems, often mediated through a solvent. In this work we employ Monte-Carlo simulation to study the collapse transition in a model molecular system interacting via both isotropic as well as anisotropic interactions having different length and energy scales. The model we use is known as Mercedes-Benz (MB), which, for a specific set of parameters, sustains two solid phases: honeycomb and oblique. In order to study the temperature induced collapse transition, we start with a metastable honeycomb solid and induce transition by increasing temperature. High density oblique solid so formed has two characteristic length scales corresponding to isotropic and anisotropic parts of interaction potential. Contrary to the common belief and classical nucleation theory, interestingly, we find linear strip-like nucleating clusters having significantly different order and average coordination number than the bulk stable phase. In the early stage of growth, the cluster grows as a linear strip, followed by branched and ring-like strips. The geometry of growing cluster is a consequence of the delicate balance between two types of interactions, which enables the dominance of stabilizing energy over destabilizing surface energy. The nucleus of stable oblique phase is wetted by intermediate order particles, which minimizes the surface free energy. In the case of pressure induced transition at low temperature the collapsed state is a disordered solid. The disordered solid phase has diverse local quasi-stable structures along with oblique-solid like domains.

Lubrication with solids.

NASA Technical Reports Server (NTRS)

Buckley, D. H.; Johnson, R. L.

1972-01-01

Brief discussion of the historical background, variety range, chemistry, physics, and other properties of solid lubricants, and review of their current uses. The widespread use of solid lubricants did not occur until about 1947. At present, they are the object of such interest that a special international conference on their subject was held in 1971. They are used at temperatures beyond the useful range of conventional lubricating oils and greases. Their low volatility provides them with the capability of functioning effectively in vacuum and invites their use in space applications. Their high load carrying ability makes them useful with heavily loaded components. Solid lubricants, however, do lack some of the desirable properties of conventional lubricants. Unlike oils and greases, which have fluidity and can continuously be carried back into contact with lubricated surfaces, solid lubricants, because of their immobility, have finite lives. Also, oils and greases can carry away frictional heat from contacting surfaces, while solid lubricants cannot.

Review on solid electrolytes for all-solid-state lithium-ion batteries

NASA Astrophysics Data System (ADS)

Zheng, Feng; Kotobuki, Masashi; Song, Shufeng; Lai, Man On; Lu, Li

2018-06-01

All-solid-state (ASS) lithium-ion battery has attracted great attention due to its high safety and increased energy density. One of key components in the ASS battery (ASSB) is solid electrolyte that determines performance of the ASSB. Many types of solid electrolytes have been investigated in great detail in the past years, including NASICON-type, garnet-type, perovskite-type, LISICON-type, LiPON-type, Li3N-type, sulfide-type, argyrodite-type, anti-perovskite-type and many more. This paper aims to provide comprehensive reviews on some typical types of key solid electrolytes and some ASSBs, and on gaps that should be resolved.

Development and Optimization of a Flocculation Procedure for Improved Solid-Liquid Separation of Digested Biomass

DOE Office of Scientific and Technical Information (OSTI.GOV)

Patton, Caroline; Lischeske, James J.; Sievers, David A.

2015-11-03

One viable treatment method for conversion of lignocellulosic biomass to biofuels begins with saccharification (thermochemical pretreatment and enzymatic hydrolysis), followed by fermentation or catalytic upgrading to fuels such as ethanol, butanol, or other hydrocarbons. The post-hydrolysis slurry is typically 4-8 percent insoluble solids, predominantly consisting of lignin. Suspended solids are known to inhibit fermentation as well as poison catalysts and obstruct flow in catalyst beds. Thus a solid-liquid separation following enzymatic hydrolysis would be highly favorable for process economics, however the material is not easily separated by filtration or gravimetric methods. Use of a polyacrylamide flocculant to bind the suspendedmore » particles in a corn stover hydrolyzate slurry into larger flocs (1-2mm diameter) has been found to be extremely helpful in improving separation. Recent and ongoing research on novel pretreatment methods yields hydrolyzate material with diverse characteristics. Therefore, we need a thorough understanding of rapid and successful flocculation design in order to quickly achieve process design goals. In this study potential indicators of flocculation performance were investigated in order to develop a rapid analysis method for flocculation procedure in the context of a novel hydrolyzate material. Flocculation conditions were optimized on flocculant type and loading, pH, and mixing time. Filtration flux of the hydrolyzate slurry was improved 170-fold using a cationic polyacrylamide flocculant with a dosing of approximately 22 mg flocculant/g insoluble solids at an approximate pH of 3. With cake washing, sugar recovery exceeded 90 percent with asymptotic yield at 15 L wash water/kg insoluble solids.« less

Applications of Polymers as Pharmaceutical Excipients in Solid Oral Dosage Forms.

PubMed

Debotton, Nir; Dahan, Arik

2017-01-01

Over the last few decades, polymers have been extensively used as pharmaceutical excipients in drug delivery systems. Pharmaceutical polymers evolved from being simply used as gelatin shells comprising capsule to offering great formulation advantages including enabling controlled/slow release and specific targeting of drugs to the site(s) of action (the "magic bullets" concept), hence hold a significant clinical promise. Oral administration of solid dosage forms (e.g., tablets and capsules) is the most common and convenient route of drug administration. When formulating challenging molecules into solid oral dosage forms, polymeric pharmaceutical excipients permit masking undesired physicochemical properties of drugs and consequently, altering their pharmacokinetic profiles to improve the therapeutic effect. As a result, the number of synthetic and natural polymers available commercially as pharmaceutical excipients has increased dramatically, offering potential solutions to various difficulties. For instance, the different polymers may allow increased solubility, swellability, viscosity, biodegradability, advanced coatings, pH dependency, mucodhesion, and inhibition of crystallization. The aim of this article is to provide a wide angle prospect of the different uses of pharmaceutical polymers in solid oral dosage forms. The various types of polymeric excipients are presented, and their distinctive role in oral drug delivery is emphasized. The comprehensive know-how provided in this article may allow scientists to use these polymeric excipients rationally, to fully exploit their different features and potential influence on drug delivery, with the overall aim of making better drug products. © 2016 Wiley Periodicals, Inc.

The role of (dis)inhibition in creativity: decreased inhibition improves idea generation.

PubMed

Radel, Rémi; Davranche, Karen; Fournier, Marion; Dietrich, Arne

2015-01-01

There is now a large body of evidence showing that many different conditions related to impaired fronto-executive functioning are associated with the enhancement of some types of creativity. In this paper, we pursue the possibility that the central mechanism associated with this effect might be a reduced capacity to exert inhibition. We tested this hypothesis by exhausting the inhibition efficiency through prolonged and intensive practice of either the Simon or the Eriksen Flanker task. Performance on another inhibition task indicated that only the cognitive resources for inhibition of participants facing high inhibition demands were impaired. Subsequent creativity tests revealed that exposure to high inhibition demands led to enhanced fluency in a divergent thinking task (Alternate Uses Task), but no such changes occurred in a convergent task (Remote Associate Task; studies 1a and 1b). The same manipulation also led to a hyper-priming effect for weakly related primes in a Lexical Decision Task (Study 2). Together, these findings suggest that inhibition selectively affects some types of creative processes and that, when resources for inhibition are lacking, the frequency and the originality of ideas was facilitated. Copyright © 2014 Elsevier B.V. All rights reserved.

Evaluation of the recrystallization kinetics of hot-melt extruded polymeric solid dispersions using an improved Avrami equation

PubMed Central

Feng, Xin; Ye, Xingyou; Park, Jun-Bom; Lu, Wenli; Morott, Joe; Beissner, Brad; Lian, Zhuoyang John; Pinto, Elanor; Bi, Vivian; Porter, Stu; Durig, Tom; Majumdar, Soumyajit; Repka, Michael A.

2017-01-01

The recrystallization of an amorphous drug in a solid dispersion system could lead to a loss in the drug solubility and bioavailability. The primary objective of the current research was to use an improved kinetic model to evaluate the recrystallization kinetics of amorphous structures and to further understand the factors influencing the physical stability of amorphous solid dispersions. Amorphous solid dispersions of fenofibrate with different molecular weights of hydroxypropylcellulose, HPC (Klucel™ LF, EF, ELF) were prepared utilizing hot-melt extrusion technology. Differential scanning calorimetry was utilized to quantitatively analyze the extent of recrystallization in the samples stored at different temperatures and relative humidity (RH) conditions. The experimental data were fitted into the improved kinetics model of a modified Avrami equation to calculate the recrystallization rate constants. Klucel LF, the largest molecular weight among the HPCs used, demonstrated the greatest inhibition of fenofibrate recrystallization. Additionally, the recrystallization rate (k) decreased with increasing polymer content, however exponentially increased with higher temperature. Also k increased linearly rather than exponentially over the range of RH studied. PMID:25224341

Evaluation of the recrystallization kinetics of hot-melt extruded polymeric solid dispersions using an improved Avrami equation.

PubMed

Feng, Xin; Ye, Xingyou; Park, Jun-Bom; Lu, Wenli; Morott, Joe; Beissner, Brad; Lian, Zhuoyang John; Pinto, Elanor; Bi, Vivian; Porter, Stu; Durig, Tom; Majumdar, Soumyajit; Repka, Michael A

2015-01-01

The recrystallization of an amorphous drug in a solid dispersion system could lead to a loss in the drug solubility and bioavailability. The primary objective of the current research was to use an improved kinetic model to evaluate the recrystallization kinetics of amorphous structures and to further understand the factors influencing the physical stability of amorphous solid dispersions. Amorphous solid dispersions of fenofibrate with different molecular weights of hydroxypropylcellulose, HPC (Klucel™ LF, EF, ELF) were prepared utilizing hot-melt extrusion technology. Differential scanning calorimetry was utilized to quantitatively analyze the extent of recrystallization in the samples stored at different temperatures and relative humidity (RH) conditions. The experimental data were fitted into the improved kinetics model of a modified Avrami equation to calculate the recrystallization rate constants. Klucel LF, the largest molecular weight among the HPCs used, demonstrated the greatest inhibition of fenofibrate recrystallization. Additionally, the recrystallization rate (k) decreased with increasing polymer content, however exponentially increased with higher temperature. Also k increased linearly rather than exponentially over the range of RH studied.

Nanoscale hydrodynamics near solids

NASA Astrophysics Data System (ADS)

Camargo, Diego; de la Torre, J. A.; Duque-Zumajo, D.; Español, Pep; Delgado-Buscalioni, Rafael; Chejne, Farid

2018-02-01

Density Functional Theory (DFT) is a successful and well-established theory for the study of the structure of simple and complex fluids at equilibrium. The theory has been generalized to dynamical situations when the underlying dynamics is diffusive as in, for example, colloidal systems. However, there is no such a clear foundation for Dynamic DFT (DDFT) for the case of simple fluids in contact with solid walls. In this work, we derive DDFT for simple fluids by including not only the mass density field but also the momentum density field of the fluid. The standard projection operator method based on the Kawasaki-Gunton operator is used for deriving the equations for the average value of these fields. The solid is described as featureless under the assumption that all the internal degrees of freedom of the solid relax much faster than those of the fluid (solid elasticity is irrelevant). The fluid moves according to a set of non-local hydrodynamic equations that include explicitly the forces due to the solid. These forces are of two types, reversible forces emerging from the free energy density functional, and accounting for impenetrability of the solid, and irreversible forces that involve the velocity of both the fluid and the solid. These forces are localized in the vicinity of the solid surface. The resulting hydrodynamic equations should allow one to study dynamical regimes of simple fluids in contact with solid objects in isothermal situations.

Energy properties of solid fossil fuels and solid biofuels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holubcik, Michal, E-mail: michal.holubcik@fstroj.uniza.sk; Jandacka, Jozef, E-mail: jozef.jandacka@fstroj.uniza.sk; Kolkova, Zuzana, E-mail: zuzana.kolkova@rc.uniza.sk

The paper deals about the problematic of energy properties of solid biofuels in comparison with solid fossil fuels. Biofuels are alternative to fossil fuels and their properties are very similar. During the experiments were done in detail experiments to obtain various properties of spruce wood pellets and wheat straw pellets like biofuels in comparison with brown coal and black coal like fossil fuels. There were tested moisture content, volatile content, fixed carbon content, ash content, elementary analysis (C, H, N, S content) and ash fusion temperatures. The results show that biofuels have some advantages and also disadvantages in comparison withmore » solid fossil fuels.« less

Rotary bulk solids divider

DOEpatents

Maronde, Carl P.; Killmeyer, Jr., Richard P.

1992-01-01

An apparatus for the disbursement of a bulk solid sample comprising, a gravity hopper having a top open end and a bottom discharge end, a feeder positioned beneath the gravity hopper so as to receive a bulk solid sample flowing from the bottom discharge end, and a conveyor receiving the bulk solid sample from the feeder and rotating on an axis that allows the bulk solid sample to disperse the sample to a collection station.

ROTARY BULK SOLIDS DIVIDER

DOEpatents

Maronde, Carl P.; Killmeyer JR., Richard P.

1992-03-03

An apparatus for the disbursement of a bulk solid sample comprising, a gravity hopper having a top open end and a bottom discharge end, a feeder positioned beneath the gravity hopper so as to receive a bulk solid sample flowing from the bottom discharge end, and a conveyor receiving the bulk solid sample from the feeder and rotating on an axis that allows the bulk solid sample to disperse the sample to a collection station.

Stability of Electrodeposition at Solid-Solid Interfaces and Implications for Metal Anodes

NASA Astrophysics Data System (ADS)

Ahmad, Zeeshan; Viswanathan, Venkatasubramanian

2017-08-01

We generalize the conditions for stable electrodeposition at isotropic solid-solid interfaces using a kinetic model which incorporates the effects of stresses and surface tension at the interface. We develop a stability diagram that shows two regimes of stability: a previously known pressure-driven mechanism and a new density-driven stability mechanism that is governed by the relative density of metal in the two phases. We show that inorganic solids and solid polymers generally do not lead to stable electrodeposition, and provide design guidelines for achieving stable electrodeposition.

History of Solid Rockets

NASA Technical Reports Server (NTRS)

Green, Becky; Hales, Christy

2017-01-01

Solid rockets were created by accident and their design and uses have evolved over time. Solid rockets are more simple and reliable than liquid rockets, but they have reduced performance capability. All solid rockets have a similar set of failure modes.

Simulations of small solid accretion on to planetesimals in the presence of gas

NASA Astrophysics Data System (ADS)

Hughes, A. G.; Boley, A. C.

2017-12-01

The growth and migration of planetesimals in a young protoplanetary disc are fundamental to planet formation. In all models of early growth, there are several processes that can inhibit grains from reaching larger sizes. Nevertheless, observations suggest that growth of planetesimals must be rapid. If a small number of 100 km sized planetesimals do manage to form in the disc, then gas drag effects could enable them to efficiently accrete small solids from beyond their gravitationally focused cross-section. This gas-drag-enhanced accretion can allow planetesimals to grow at rapid rates, in principle. We present self-consistent hydrodynamics simulations with direct particle integration and gas-drag coupling to estimate the rate of planetesimal growth due to pebble accretion. Wind tunnel simulations are used to explore a range of particle sizes and disc conditions. We also explore analytic estimates of planetesimal growth and numerically integrate planetesimal drift due to the accretion of small solids. Our results show that, for almost every case that we consider, there is a clearly preferred particle size for accretion that depends on the properties of the accreting planetesimal and the local disc conditions. For solids much smaller than the preferred particle size, accretion rates are significantly reduced as the particles are entrained in the gas and flow around the planetesimal. Solids much larger than the preferred size accrete at rates consistent with gravitational focusing. Our analytic estimates for pebble accretion highlight the time-scales that are needed for the growth of large objects under different disc conditions and initial planetesimal sizes.

Molecular targeted therapies for solid tumors: management of side effects.

PubMed

Grünwald, Viktor; Soltau, Jens; Ivanyi, Philipp; Rentschler, Jochen; Reuter, Christoph; Drevs, Joachim

2009-03-01

This review will provide physicians and oncologists with an overview of side effects related to targeted agents that inhibit vascular endothelial growth factor (VEGF), epidermal growth factor (EGF) and mammalian target of rapamycin (mTOR) signaling in the treatment of solid tumors. Such targeted agents can be divided into monoclonal antibodies, tyrosine kinase inhibitors, multitargeted tyrosine kinase inhibitors and serine/threonine kinase inhibitors. Molecular targeted therapies are generally well tolerated, but inhibitory effects on the biological function of the targets in healthy tissue can result in specific treatment-related side effects, particularly with multitargeted agents. We offer some guidance on how to manage adverse events in cancer patients based on the range of options currently available. Copyright 2009 S. Karger AG, Basel.

Arsenic trioxide inhibits cell proliferation and human papillomavirus oncogene expression in cervical cancer cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Hongtao; Gao, Peng; Zheng, Jie, E-mail: jiezheng54@126.com

Highlights: • As{sub 2}O{sub 3} inhibits growth of cervical cancer cells and expression of HPV oncogenes in these cells. • HPV-negative cervical cancer cells are more sensitive to As{sub 2}O{sub 3} than HPV-positive cervical cancer cells. • HPV-18 positive cervical cancer cells are more sensitive to As{sub 2}O{sub 3} than HPV-16 positive cancer cells. • Down-regulation of HPV oncogenes by As{sub 2}O{sub 3} is partially due to the diminished AP-1 binding. - Abstract: Arsenic trioxide (As{sub 2}O{sub 3}) has shown therapeutic effects in some leukemias and solid cancers. However, the molecular mechanisms of its anticancer efficacy have not been clearlymore » elucidated, particularly in solid cancers. Our previous data showed that As{sub 2}O{sub 3} induced apoptosis of human papillomavirus (HPV) 16 DNA-immortalized human cervical epithelial cells and cervical cancer cells and inhibited the expression of HPV oncogenes in these cells. In the present study, we systemically examined the effects of As{sub 2}O{sub 3} on five human cervical cancer cell lines and explored the possible molecular mechanisms. MTT assay showed that HPV-negative C33A cells were more sensitive to growth inhibition induced by As{sub 2}O{sub 3} than HPV-positive cervical cancer cells, and HPV 18-positive HeLa and C4-I cells were more sensitive to As{sub 2}O{sub 3} than HPV 16-positive CaSki and SiHa cells. After As{sub 2}O{sub 3} treatment, both mRNA and protein levels of HPV E6 and E7 obviously decreased in all HPV positive cell lines. In contrast, p53 and Rb protein levels increased in all tested cell lines. Transcription factor AP-1 protein expression decreased significantly in HeLa, CaSki and C33A cells with ELISA method. These results suggest that As{sub 2}O{sub 3} is a potential anticancer drug for cervical cancer.« less

Barrier coated drug layered particles for enhanced performance of amorphous solid dispersion dosage form.

PubMed

Puri, Vibha; Dantuluri, Ajay K; Bansal, Arvind K

2012-01-01

Amorphous solid dispersions (ASDs) may entail tailor-made dosage form design to exploit their solubility advantage. Surface phenomena dominated the performance of amorphous celecoxib solid dispersion (ACSD) comprising of amorphous celecoxib (A-CLB), polyvinylpyrrolidone, and meglumine (7:2:1, w/w). ACSD cohesive interfacial interactions hindered its capsule dosage form dissolution (Puri V, Dhantuluri AK, Bansal AK 2011. J Pharm Sci 100:2460-2468). Furthermore, ACSD underwent significant devitrification under environmental stress. In the present study, enthalpy relaxation studies revealed its free surface to contribute to molecular mobility. Based on all these observations, barrier coated amorphous CLB solid dispersion layered particles (ADLP) were developed by Wurster process, using microcrystalline cellulose as substrate and polyvinyl alcohol (PVA), inulin, and polyvinyl acetate phthalate (PVAP) as coating excipients. Capsule formulations of barrier coated-ADLP could achieve rapid dispersibility and high drug release. Evaluation under varying temperature and RH conditions suggested the crystallization inhibitory efficiency in order of inulin < PVA ≈ PVAP; however, under only temperature treatment, crystallization inhibition increased with increase in T(g) of the coating material. Simulated studies using DSC evidenced drug-polymer mixing at the interface as a potential mechanism for surface stabilization. In conclusion, surface modification yielded a fast dispersing robust high drug load ASD based dosage form. Copyright © 2011 Wiley-Liss, Inc.

A continuum treatment of sliding in Eulerian simulations of solid-solid and solid-fluid interfaces

NASA Astrophysics Data System (ADS)

Subramaniam, Akshay; Ghaisas, Niranjan; Lele, Sanjiva

2017-11-01

A novel treatment of sliding is developed for use in an Eulerian framework for simulating elastic-plastic deformations of solids coupled with fluids. In this method, embedded interfacial boundary conditions for perfect sliding are imposed by enforcing the interface normal to be a principal direction of the Cauchy stress and appropriate consistency conditions ensure correct transmission and reflection of waves at the interface. This sliding treatment may be used either to simulate a solid-solid sliding interface or to incorporate an internal slip boundary condition at a solid-fluid interface. Sliding laws like the Coulomb friction law can also be incorporated with relative ease into this framework. Simulations of sliding interfaces are conducted using a 10th order compact finite difference scheme and a Localized Artificial Diffusivity (LAD) scheme for shock and interface capturing. 1D and 2D simulations are used to assess the accuracy of the sliding treatment. The Richmyer-Meshkov instability between copper and aluminum is simulated with this sliding treatment as a demonstration test case. Support for this work was provided through Grant B612155 from the Lawrence Livermore National Laboratory, US Department of Energy.

High-Performance Schottky Diode Gas Sensor Based on the Heterojunction of Three-Dimensional Nanohybrids of Reduced Graphene Oxide-Vertical ZnO Nanorods on an AlGaN/GaN Layer.

PubMed

Minh Triet, Nguyen; Thai Duy, Le; Hwang, Byeong-Ung; Hanif, Adeela; Siddiqui, Saqib; Park, Kyung-Ho; Cho, Chu-Young; Lee, Nae-Eung

2017-09-13

A Schottky diode based on a heterojunction of three-dimensional (3D) nanohybrid materials, formed by hybridizing reduced graphene oxide (RGO) with epitaxial vertical zinc oxide nanorods (ZnO NRs) and Al 0.27 GaN 0.73 (∼25 nm)/GaN is presented as a new class of high-performance chemical sensors. The RGO nanosheet layer coated on the ZnO NRs enables the formation of a direct Schottky contact with the AlGaN layer. The sensing results of the Schottky diode with respect to NO 2 , SO 2 , and HCHO gases exhibit high sensitivity (0.88-1.88 ppm -1 ), fast response (∼2 min), and good reproducibility down to 120 ppb concentration levels at room temperature. The sensing mechanism of the Schottky diode can be explained by the effective modulation of the reverse saturation current due to the change in thermionic emission carrier transport caused by ultrasensitive changes in the Schottky barrier of a van der Waals heterostructure between RGO and AlGaN layers upon interaction with gas molecules. Advances in the design of a Schottky diode gas sensor based on the heterojunction of high-mobility two-dimensional electron gas channel and highly responsive 3D-engineered sensing nanomaterials have potential not only for the enhancement of sensitivity and selectivity but also for improving operation capability at room temperature.

Path-integral simulation of solids.

PubMed

Herrero, C P; Ramírez, R

2014-06-11

The path-integral formulation of the statistical mechanics of quantum many-body systems is described, with the purpose of introducing practical techniques for the simulation of solids. Monte Carlo and molecular dynamics methods for distinguishable quantum particles are presented, with particular attention to the isothermal-isobaric ensemble. Applications of these computational techniques to different types of solids are reviewed, including noble-gas solids (helium and heavier elements), group-IV materials (diamond and elemental semiconductors), and molecular solids (with emphasis on hydrogen and ice). Structural, vibrational, and thermodynamic properties of these materials are discussed. Applications also include point defects in solids (structure and diffusion), as well as nuclear quantum effects in solid surfaces and adsorbates. Different phenomena are discussed, as solid-to-solid and orientational phase transitions, rates of quantum processes, classical-to-quantum crossover, and various finite-temperature anharmonic effects (thermal expansion, isotopic effects, electron-phonon interactions). Nuclear quantum effects are most remarkable in the presence of light atoms, so that especial emphasis is laid on solids containing hydrogen as a constituent element or as an impurity.

Nonenzymatic electrochemical detection of glucose using well-distributed nickel nanoparticles on straight multi-walled carbon nanotubes.

PubMed

Nie, Huagui; Yao, Zhen; Zhou, Xuemei; Yang, Zhi; Huang, Shaoming

2011-12-15

A nonenzymatic electrochemical sensor device was fabricated for glucose detection based on nickel nanoparticles (NiNPs)/straight multi-walled carbon nanotubes (SMWNTs) nanohybrids, which were synthesized through in situ precipitation procedure. SMWNTs can be easily dispersed in solution after mild sonication pretreatment, which facilitates the precursor of NiNPs binding to their surface and results in the homogeneous distribution of NiNPs on the surface of SMWNTs. The morphology and component of the nanohybrids were characterized by scanning electron microscopy (SEM) and X-ray powder diffraction (XRD), respectively. Cyclic voltammetry (CV) and amperometry were used to evaluate the catalytic activity of the NiNPs/SMWNTs nanohybrids modified electrode towards glucose. It was found that the nanohybrids modified electrode showed remarkably enhanced electrocatalytic activity towards the oxidation of glucose in alkaline solution compared to that of the bare glass carbon electrode (GCE), the NiNPs and the SMWNTs modified electrode, attributing to the synergistic effect of SMWNTs and Ni(2+)/Ni(3+) redox couple. Under the optimal detection conditions, the as-prepared sensors exhibited linear behavior in the concentration range from 1 μM to 1 mM for the quantification of glucose with a limit of detection of 500 nM (3σ). Moreover, the NiNPs/SMWNTs modified electrode was also relatively insensitive to commonly interfering species such as ascorbic acid (AA), uric acid (UA), dopamine (DA), galactose (GA), and xylose (XY). The robust selectivities, sensitivities, and stabilities determined experimentally indicated the great potential of NiNPs/SMWNTs nanohybrids for construction of a variety of electrochemical sensors. Copyright © 2011 Elsevier B.V. All rights reserved.

Osteoconductive Amine-Functionalized Graphene-Poly(methyl methacrylate) Bone Cement Composite with Controlled Exothermic Polymerization.

PubMed

Sharma, Rakesh; Kapusetti, Govinda; Bhong, Sayali Yashwant; Roy, Partha; Singh, Santosh Kumar; Singh, Shikha; Balavigneswaran, Chelladurai Karthikeyan; Mahato, Kaushal Kumar; Ray, Biswajit; Maiti, Pralay; Misra, Nira

2017-09-20

Bone cement has found extensive usage in joint arthroplasty over the last 50 years; still, the development of bone cement with essential properties such as high fatigue resistance, lower exothermic temperature, and bioactivity has been an unsolved problem. In our present work, we have addressed all of the mentioned shortcomings of bone cement by reinforcing it with graphene (GR), graphene oxide (GO), and surface-modified amino graphene (AG) fillers. These nanocomposites have shown hypsochromic shifts, suggesting strong interactions between the filler material and the polymer matrix. AG-based nanohybrids have shown greater osteointegration and lower cytotoxicity compared to other nanohybrids as well as pristine bone cement. They have also reduced oxidative stress on cells, resulting in calcification within 20 days of the implantation of nanohybrids into the rabbits. They have significantly reduced the exothermic curing temperature to body temperature and increased the setting time to facilitate practitioners, suggesting that reaction temperature and settling time can be dynamically controlled by varying the concentration of the filler. Thermal stability and enhanced mechanical properties have been achieved in nanohybrids vis-à-vis pure bone cement. Thus, this newly developed nanocomposite can create natural bonding with bone tissues for improved bioactivity, longer sustainability, and better strength in the prosthesis.

75 FR 34682 - Bulk Solid Hazardous Materials: Harmonization With the International Maritime Solid Bulk Cargoes...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-18

...] RIN 1625-AB47 Bulk Solid Hazardous Materials: Harmonization With the International Maritime Solid Bulk... on June 17, 2010, entitled ``Bulk Solid Hazardous Materials: Harmonization With the International Maritime Solid Bulk Cargoes (IMSBC) Code.'' This correction provides correct information with regard to the...

Self assembly of acetylcholinesterase on a gold nanoparticles–graphene nanosheet hybrid for organophosphate pesticide detection using polyelectrolyte as a linker

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Ying; Zhang, Sheng; Du, Dan

A nanohybrid of gold nanoparticles (Au NPs) and chemically reduced graphene oxide nanosheets (cr-Gs) was synthesized by in situ growth of Au NPs on the surface of graphene nanosheets in the presence of poly(diallyldimethylammonium chloride) (PDDA), which not only improved the dispersion of Au NPs but also stabilized cholinesterase with high activity and loading efficiency. The obtained nanohybrid was characterized by TEM, XRD, XPS, and electrochemistry. Then an enzyme nanoassembly (AChE/Au NPs/cr-Gs) was prepared by self-assembling acetylcholinesterase (AChE) on Au NP/cr-Gs nanohybrid. An electrochemical sensor based on AChE/Au NPs/cr-Gs was further developed for ultrasensitive detection of organophosphate pesticide. The resultsmore » demonstrate that the developed approach provides a promising strategy to improve the sensitivity and enzyme activity of electrochemical biosensors.« less

Purification of extracellular acid protease and analysis of fermentation metabolites by Synergistes sp. utilizing proteinaceous solid waste from tanneries.

PubMed

Kumar, A Ganesh; Nagesh, N; Prabhakar, T G; Sekaran, G

2008-05-01

The untanned proteinaceous tannery solid waste, animal fleshing (ANFL), was used as a substrate for acid protease production by Synergistes sp. The strain was isolated from an anaerobic digester used for the treatment of tannery solid waste and was selected for its enhanced protease production at activity 350-420 U/ml. The optimum pH was in the acidic range of 5.5-6.5 and optimum temperature was in mesophilic range of 25-35 degrees C. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and the zymogram analyses of the purified protein indicated an estimated molecular mass of 60 kDa. This protease could be classified as aspartic protease based on its inhibition by aspartate type protease inhibitor pepstatin and on non-inhibition by 1,10-phenanthroline, EDTA, EGTA and phenylmethylsulfonyl fluoride. The degradation of ANFL was confirmed by Gas Chromatography-Mass Spectroscopy (GC-MS), Proton Nuclear Magnetic Resonance Spectroscopy (H1 NMR) and Scanning Electron Microscopy (SEM) analyses. In this study we found that the activity of acid protease depended on factors such as calcium concentration, pH and temperature. Based on these lines of evidence, we postulate that this protease is a highly catalytic novel protease of its type.

76 FR 8658 - Bulk Solid Hazardous Materials: Harmonization With the International Maritime Solid Bulk Cargoes...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-15

... Solid Hazardous Materials: Harmonization With the International Maritime Solid Bulk Cargoes (IMSBC) Code..., the Coast Guard amended its regulations governing the carriage of solid hazardous materials in bulk to... hazardous bulk solid materials not addressed in the amended regulations. This notice announces that the...

Episodic Inhibition

ERIC Educational Resources Information Center

Racsmany, Mihaly; Conway, Martin A.

2006-01-01

Six experiments examined the proposal that an item of long-term knowledge can be simultaneously inhibited and activated. In 2 directed forgetting experiments items to-be-forgotten were found to be inhibited in list-cued recall but activated in lexical decision tasks. In 3 retrieval practice experiments, unpracticed items from practiced categories…

Management of solid waste

NASA Astrophysics Data System (ADS)

Thompson, W. T.; Stinton, L. H.

1980-04-01

Compliance with the latest regulatory requirements addressing disposal of radioactive, hazardous, and sanitary solid waste criteria in the selection, design, and operation of solid waste management facilities. Due to the state of flux of these regulatory requirements from EPA and NRC, several waste management options were of solid waste. The current regulatory constraints and the design and operational requirements for construction of both storage and disposal facilities for use in management of DOE-ORO solid waste are highlighted. Capital operational costs are included for both disposal and storage options.

Taurine zinc solid dispersions enhance bile-incubated L02 cell viability and improve liver function by inhibiting ERK2 and JNK phosphorylation during cholestasis.

PubMed

Wang, Yu; Mei, Xueting; Yuan, Jingquan; Lai, Xiaofang; Xu, Donghui

2016-07-29

Dietary intakes of taurine and zinc are associated with decreased risk of liver disease. In this study, solid dispersions (SDs) of a taurine zinc complex on hepatic injury were examined in vitro using the immortalized human hepatocyte cell line L02 and in a rat model of bile duct ligation. Sham-operated and bile duct ligated Sprague-Dawley rats were treated with the vehicle alone or taurine zinc (40, 80, 160mg/kg) for 17days. Bile duct ligation significantly increased blood lipid levels, and promoted hepatocyte apoptosis, inflammation and compensatory biliary proliferation. In vitro, incubation with bile significantly reduced L02 cell viability; this effect was significantly attenuated by pretreatment with SP600125 (a JNK inhibitor) and enhanced when co-incubated with taurine zinc SDs. In vivo, administration of taurine zinc SDs decreased serum alanine aminotransferase and aspartate aminotransferase activities in a dose-dependent manner and attenuated the increases in serum total bilirubin, total cholesterol and low density lipoprotein cholesterol levels after bile duct ligation. Additionally, taurine zinc SDs downregulated the expression of interleukin-1β and inhibited the phosphorylation of Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase2 (ERK2) in the liver after bile duct ligation. Moreover, taurine zinc SDs had more potent blood lipid regulatory and anti-apoptotic effects than the physical mixture of taurine and zinc acetate. Therefore, we speculate that taurine zinc SDs protect liver function at least in part via a mechanism linked to reduce phosphorylation of JNK and ERK2, which suppresses inflammation, apoptosis and cholangiocyte proliferation during cholestasis. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Role of the Strength of Drug-Polymer Interactions on the Molecular Mobility and Crystallization Inhibition in Ketoconazole Solid Dispersions.

PubMed

Mistry, Pinal; Mohapatra, Sarat; Gopinath, Tata; Vogt, Frederick G; Suryanarayanan, Raj

2015-09-08

The effects of specific drug-polymer interactions (ionic or hydrogen-bonding) on the molecular mobility of model amorphous solid dispersions (ASDs) were investigated. ASDs of ketoconazole (KTZ), a weakly basic drug, with each of poly(acrylic acid) (PAA), poly(2-hydroxyethyl methacrylate) (PHEMA), and polyvinylpyrrolidone (PVP) were prepared. Drug-polymer interactions in the ASDs were evaluated by infrared and solid-state NMR, the molecular mobility quantified by dielectric spectroscopy, and crystallization onset monitored by differential scanning calorimetry (DSC) and variable temperature X-ray diffractometry (VTXRD). KTZ likely exhibited ionic interactions with PAA, hydrogen-bonding with PHEMA, and weaker dipole-dipole interactions with PVP. On the basis of dielectric spectroscopy, the α-relaxation times of the ASDs followed the order: PAA > PHEMA > PVP. In addition, the presence of ionic interactions also translated to a dramatic and disproportionate decrease in mobility as a function of polymer concentration. On the basis of both DSC and VTXRD, an increase in strength of interaction translated to higher crystallization onset temperature and a decrease in extent of crystallization. Stronger drug-polymer interactions, by reducing the molecular mobility, can potentially delay the crystallization onset temperature as well as crystallization extent.

Fluid-solid coupled simulation of the ignition transient of solid rocket motor

NASA Astrophysics Data System (ADS)

Li, Qiang; Liu, Peijin; He, Guoqiang

2015-05-01

The first period of the solid rocket motor operation is the ignition transient, which involves complex processes and, according to chronological sequence, can be divided into several stages, namely, igniter jet injection, propellant heating and ignition, flame spreading, chamber pressurization and solid propellant deformation. The ignition transient should be comprehensively analyzed because it significantly influences the overall performance of the solid rocket motor. A numerical approach is presented in this paper for simulating the fluid-solid interaction problems in the ignition transient of the solid rocket motor. In the proposed procedure, the time-dependent numerical solutions of the governing equations of internal compressible fluid flow are loosely coupled with those of the geometrical nonlinearity problems to determine the propellant mechanical response and deformation. The well-known Zeldovich-Novozhilov model was employed to model propellant ignition and combustion. The fluid-solid coupling interface data interpolation scheme and coupling instance for different computational agents were also reported. Finally, numerical validation was performed, and the proposed approach was applied to the ignition transient of one laboratory-scale solid rocket motor. For the application, the internal ballistics were obtained from the ground hot firing test, and comparisons were made. Results show that the integrated framework allows us to perform coupled simulations of the propellant ignition, strong unsteady internal fluid flow, and propellant mechanical response in SRMs with satisfactory stability and efficiency and presents a reliable and accurate solution to complex multi-physics problems.

Dynamic mechanical thermal properties of the dental light-cured nanohybrid composite Kalore, GC: effect of various food/oral simulating liquids.

PubMed

Sideridou, Irini D; Vouvoudi, Evangelia C; Adamidou, Evanthia A

2015-02-01

The aim of this work is the study of the dynamic mechanical thermal properties (viscoelastic properties) of a current dental commercial light-cured nanohybrid resin composite, Kalore, GC (GC Corporation, Tokyo, Japan) along with the study of the effect of some food/oral simulating liquids (FSLs) on these properties. Dynamic mechanical thermal analysis (DMTA) tests were performed on a Diamond Dynamic Mechanical Thermal Analyzer in bending mode. A frequency of 1Hz and a temperature range of 25-185°C were applied, while the heating rate of 2°C/min was selected to cover mouth temperature and the material's likely Tg. The properties were determined after storage in air, distilled water, heptane, ethanol/water solution (75% v/v) or absolute ethanol at 37°C for up to 1h, 1, 7 or 30 days. Storage modulus, loss modulus and tangent delta (tanδ) were plotted against temperature. The glass transition temperatures are taken from the peak of the tangent tanδ versus temperature curves. Moreover, some factors indicating the heterogeneity of the polymer matrix, such as the width (ΔT) at the half of tanδ peak and the "ζ" parameter were determined. All samples analyzed after storage for 1h or 1 day in the aging media showed two Tg values. All samples analyzed after storage for 7 or 30 days in the ageing media showed a unique Tg value. Storage of Kalore GC in dry air, water or heptane at 37°C for 7 days caused post-curing reactions. Storage in air or water for 30 days did not seem to cause further effects. Storage in heptane for 30 days may cause plasticization and probably some degradation of the filler-silane bond and polymer matrix. Storage in ethanol/water solution (75% v/v) or ethanol for 7 days seems to cause post-curing reactions and degradation reactions of the matrix-filler bonds. Storage in ethanol for 30 days caused a strong change of the sample morphology and the DMTA results were not reliable. Copyright © 2014 Academy of Dental Materials. Published by Elsevier

ATG-Fresenius inhibits blood circulating cell proliferation in a dose-dependent manner: an experimental study.

PubMed

Werner, I; Seitz-Merwald, I; Kiessling, A H; Kur, F; Beiras-Fernandez, A

2014-11-01

Antithymocyte globulin (ATG)-Fresenius (Neovii-Biotech, Graefelfing, Germany), a highly purified rabbit polyclonal antihuman T-lymphocyte immunoglobulin resulting from immunization of rabbits with the Jurkat T-lymphoblast cell line, is currently used for the prevention of acute rejection in patients receiving solid organ transplants. Our aim was to investigate the in vitro activity of ATG-Fresenius regarding the proliferation of peripheral blood mononuclear cells (PBMCs), an important mechanism of rejection after solid organ transplantation. PBMCs were isolated from 6 healthy donors. Proliferation was assayed using [(3)H] thymidine incorporation. For analysis of mitogen-stimulated proliferation, the PBMCs were incubated at 37°C with various concentrations of ATG-Fresenius in the absence/presence of 40 μg/mL phytohemagglutinin. For analysis of the mixed lymphocyte reaction, PBMCs were incubated at 37°C with various concentrations of ATG-Fresenius for 3 days. On day 3, PBMCs (stimulator cells) from allogeneic donors were incubated with 25 μg/mL mitomycin C. The responder cells (preincubated with ATG-Fresenius) were then cultured at 37°C with the stimulator cells for 6 days. Groups were compared using ANOVA and the Tukey-Kramer multiple comparison test. Preincubation of PBMCs with ATG results in concentration-dependent inhibition of phytohemagglutinin-stimulated proliferation. The effect was more pronounced after 2 and 3 days of treatment with ATG compared with 1 day. There was a concentration-dependent decrease in the mixed lymphocyte reaction-induced proliferation (up to 80%) at ATG-Fresenius concentrations as low as 0.05 to 0.5 μg/mL. No further effect on proliferation at ATG-Fresenius concentrations of 0.5 to 50 μg/mL was seen, and higher concentrations (>100 μg/mL) totally inhibited proliferation. Our in vitro results provide more evidence of the beneficial effect of ATGs in the early phase of solid organ transplantation, by reducing effector cell

Ethanol production from food waste at high solids content with vacuum recovery technology.

PubMed

Huang, Haibo; Qureshi, Nasib; Chen, Ming-Hsu; Liu, Wei; Singh, Vijay

2015-03-18

Ethanol production from food wastes does not only solve environmental issues but also provides renewable biofuels. This study investigated the feasibility of producing ethanol from food wastes at high solids content (35%, w/w). A vacuum recovery system was developed and applied to remove ethanol from fermentation broth to reduce yeast ethanol inhibition. A high concentration of ethanol (144 g/L) was produced by the conventional fermentation of food waste without a vacuum recovery system. When the vacuum recovery is applied to the fermentation process, the ethanol concentration in the fermentation broth was controlled below 100 g/L, thus reducing yeast ethanol inhibition. At the end of the conventional fermentation, the residual glucose in the fermentation broth was 5.7 g/L, indicating incomplete utilization of glucose, while the vacuum fermentation allowed for complete utilization of glucose. The ethanol yield for the vacuum fermentation was found to be 358 g/kg of food waste (dry basis), higher than that for the conventional fermentation at 327 g/kg of food waste (dry basis).

Liquid phase products and solid deposit formation from thermally stressed model jet fuels

NASA Technical Reports Server (NTRS)

Kim, W. S.; Bittker, D. A.

1984-01-01

The relationship between solid deposit formation and liquid degradation product concentration was studied for the high temperature (400 C) stressing of three hydrocarbon model fuels. A Jet Fuel Thermal Oxidation Tester was used to simulate actual engine fuel system conditions. The effects of fuel type, dissolved oxygen concentration, and hot surface contact time (reaction time) were studied. Effects of reaction time and removal of dissolved oxygen on deposit formation were found to be different for n-dodecane and for 2-ethylnaphthalene. When ten percent tetralin is added to n-dodecane to give a simpler model of an actual jet fuel, the tetralin inhibits both the deposit formation and the degradation of n-dodecane. For 2-ethylnaphthalene primary product analyses indicate a possible self-inhibition at long reaction times of the secondary reactions which form the deposit precursors. The mechanism of the primary breakdown of these fuels is suggested and the primary products which participate in these precursor-forming reactions are identified. Some implications of the results to the thermal degradation of real jet fuels are given.

Cross-Linked Nanohybrid Polymer Electrolytes With POSS Cross-Linker for Solid-State Lithium Ion Batteries.

PubMed

Zhang, Jinfang; Li, Xiaofeng; Li, Ying; Wang, Huiqi; Ma, Cheng; Wang, Yanzhong; Hu, Shengliang; Wei, Weifeng

2018-01-01

A new class of freestanding cross-linked hybrid polymer electrolytes (HPEs) with POSS as the cross-linker was prepared by a one-step free radical polymerization reaction. Octavinyl octasilsesquioxane (OV-POSS) with eight functional corner groups was used to provide cross-linking sites for the connection of polymer segments and the required mechanical strength to separate the cathode and anode. The unique cross-linked structure offers additional free volume for the motion of EO chains and provides fast and continuously interconnected ion-conducting channels along the nanoparticles/polymer matrix interface. The HPE exhibits the highest ionic conductivity of 1.39 × 10 -3 S cm -1 , as well as excellent interfacial compatibility with the Li electrode at 80°C. In particular, LiFePO 4 /Li cells based on the HPE deliver good rate capability and long-term cycling performance with an initial discharge capacity of 152.1 mAh g -1 and a capacity retention ratio of 88% after 150 cycles with a current density of 0.5 C at 80°C, demonstrating great potential application in high-performance LIBs at elevated temperatures.

Cross-linked Nanohybrid Polymer Electrolytes with POSS Cross-linker for Solid-state Lithium Ion Batteries

NASA Astrophysics Data System (ADS)

Zhang, Jinfang; Li, Xiaofeng; Li, Ying; Wang, Huiqi; Ma, Cheng; Wang, Yanzhong; Hu, Shengliang; Wei, Weifeng

2018-05-01

A new class of freestanding cross-linked hybrid polymer electrolytes (HPEs) with POSS as the cross-linker was prepared by a one-step free radical polymerization reaction. Octavinyl octasilsesquioxane (OV-POSS) with eight functional corner groups was used to provide cross-linking sites for the connection of polymer segments and the required mechanical strength to separate the cathode and anode. The unique cross-linked structure offers additional free volume for the motion of EO chains and provides fast and continuously interconnected ion-conducting channels along the nanoparticles/polymer matrix interface. The HPE exhibits the highest ionic conductivity of 1.39×10-3 S cm-1, as well as excellent interfacial compatibility with the Li electrode at 80 oC. In particular, LiFePO4/Li cells based on the HPE deliver good rate capability and long-term cycling performance with an initial discharge capacity of 152.1 mAh g-1 and a capacity retention ratio of 88% after 150 cycles with a current density of 0.5 C at 80 oC, demonstrating great potential application in high-performance LIBs at elevated temperatures.

Semi-continuous anaerobic digestion of solid poultry slaughterhouse waste: effect of hydraulic retention time and loading.

PubMed

Salminen, Esa A; Rintala, Jukka A

2002-07-01

We studied the effect of hydraulic retention time (HRT) and loading on anaerobic digestion of poultry slaughterhouse wastes, using semi-continuously fed, laboratory-scale digesters at 31 degrees C. The effect on process performance was highly significant: Anaerobic digestion appeared feasible with a loading of up to 0.8 kg volatile solids (VS)/m3 d and an HRT of 50-100 days. The specific methane yield was high, from 0.52 to 0.55 m3/kg VS(added). On the other hand, at a higher loading, in the range from 1.0 to 2.1 kg VS/m3 d, and a shorter HRT, in the range from 25 to 13 days, the process appeared inhibited and/or overloaded, as indicated by the accumulation of volatile fatty acids and long-chain fatty acids and the decline in the methane yield. However, the inhibition was reversible. The nitrogen in the feed, ca. 7.8% of total solids (TS), was organic nitrogen with little ammonia present, whereas in the digested material ammonia accounted for 52-67% (up to 3.8 g/l) of total nitrogen. The TS and VS removals amounted to 76% and 64%, respectively. Our results show that on a continuous basis under the studied conditions and with a loading of up to 0.8 kg VS/m3 d metric ton (wet weight) of the studied waste mixture could yield up to 140 m3 of methane.

Mixed oxide solid solutions

DOEpatents

Magno, Scott; Wang, Ruiping; Derouane, Eric

2003-01-01

The present invention is a mixed oxide solid solution containing a tetravalent and a pentavalent cation that can be used as a support for a metal combustion catalyst. The invention is furthermore a combustion catalyst containing the mixed oxide solid solution and a method of making the mixed oxide solid solution. The tetravalent cation is zirconium(+4), hafnium(+4) or thorium(+4). In one embodiment, the pentavalent cation is tantalum(+5), niobium(+5) or bismuth(+5). Mixed oxide solid solutions of the present invention exhibit enhanced thermal stability, maintaining relatively high surface areas at high temperatures in the presence of water vapor.

Inhibition of lactation.

PubMed

Llewellyn-Jones, D

1975-01-01

The mechanism and hormonal regulation of lactation is explained and illustrated with a schematic representation. Circulating estrogen above a critical amount seems to be the inhibitory factor controlling lactation during pregnancy. Once delivery occurs, the level of estrogen falls, that of prolactin rises, and lactation begins. Nonsuckling can be used to inhibit lactation. Estrogens can also be used to inhibit lactation more quickly and with less pain. The reported association between estrogens and puerperal thromboembolism cannot be considered conclusive due to defects in the reporting studies. There is no reason not to use estrogens in lactation inhibition except for women over 35 who experienced a surgical delivery. Alternative therapy is available for these women. The recently-developed drug, brom-ergocryptine, may replace other methods of lactation inhibition.

Next generation solid boosters

NASA Technical Reports Server (NTRS)

Lund, R. K.

1991-01-01

Space transportation solid rocket motor systems; Shuttle derived heavy lift launch vehicles; advanced launch system (ALS) derived heavy lift launch vehicles; large launch solid booster vehicles are outlined. Performance capabilities and concept objectives are presented. Small launch vehicle concepts; enabling technologies; reusable flyback booster system; and high-performance solid motors for space are briefly described. This presentation is represented by viewgraphs.

Improved solid aerosol generator

DOEpatents

Prescott, D.S.; Schober, R.K.; Beller, J.

1988-07-19

An improved solid aerosol generator used to produce a gas borne stream of dry, solid particles of predetermined size and concentration. The improved solid aerosol generator nebulizes a feed solution of known concentration with a flow of preheated gas and dries the resultant wet heated aerosol in a grounded, conical heating chamber, achieving high recovery and flow rates. 2 figs.

Hypothermia Inhibits Endothelium-Independent Vascular Contractility via Rho-kinase Inhibition

PubMed Central

Chung, Yoon Hee; Oh, Keon Woong; Kim, Sung Tae; Park, Eon Sub; Je, Hyun Dong; Yoon, Hyuk-Jun; Sohn, Uy Dong; Jeong, Ji Hoon; La, Hyen-Oh

2018-01-01

The present study was undertaken to investigate the influence of hypothermia on endothelium-independent vascular smooth muscle contractility and to determine the mechanism underlying the relaxation. Denuded aortic rings from male rats were used and isometric contractions were recorded and combined with molecular experiments. Hypothermia significantly inhibited fluoride-, thromboxane A2-, phenylephrine-, and phorbol ester-induced vascular contractions regardless of endothelial nitric oxide synthesis, suggesting that another pathway had a direct effect on vascular smooth muscle. Hypothermia significantly inhibited the fluoride-induced increase in pMYPT1 level and phorbol ester-induced increase in pERK1/2 level, suggesting inhibition of Rho-kinase and MEK activity and subsequent phosphorylation of MYPT1 and ERK1/2. These results suggest that the relaxing effect of moderate hypothermia on agonist-induced vascular contraction regardless of endothelial function involves inhibition of Rho-kinase and MEK activities. PMID:28208012

Effect of solid-meal caloric content on gastric emptying kinetics of solids and liquids.

PubMed

Urbain, J L; Siegel, J A; Mortelmans, L; van Cutsem, E; van den Maegdenbergh, V; de Roo, M

1989-08-01

In this study, we have evaluated the effect of the caloric content of a physiological test meal on the gastric emptying kinetics of solids and liquids. 22 healthy male volunteers were studied in two groups matched for age. After an overnight fast, each volunteer underwent the same test procedure; in the first group (G I), 10 volunteers received a meal consisting of bread, 111In-DTPA water and 1 scrambled egg labeled with 99mTc-labelled sulphur colloid; in the second group (G II) 12 volunteers were given the same meal but with 2 labeled eggs in order to increase the caloric content of the solid phase meal. Simultaneous anterior and posterior images were recorded using a dual-headed gamma camera. Solid and liquid geometric mean data were analyzed to determine the lag phase, the emptying rate and the half-emptying time for both solids and liquids. Solid and liquid gastric half-emptying times were significantly prolonged in G II compared to G I volunteers. For the solid phased, the delay was accounted for by a longer lag phase and a decrease in the equilibrium emptying rate. The emptying rate of the liquid phase was significantly decreased in G II compared to G I. Within each group, no statistically significant difference was observed between solid and liquid emptying rates. We conclude that the caloric content of the solid portion of a meal not only alters the emptying of the solid phase but also affects the emptying of the liquid component of the meal.

Semantic processing and response inhibition.

PubMed

Chiang, Hsueh-Sheng; Motes, Michael A; Mudar, Raksha A; Rao, Neena K; Mansinghani, Sethesh; Brier, Matthew R; Maguire, Mandy J; Kraut, Michael A; Hart, John

2013-11-13

The present study examined functional MRI (fMRI) BOLD signal changes in response to object categorization during response selection and inhibition. Young adults (N=16) completed a Go/NoGo task with varying object categorization requirements while fMRI data were recorded. Response inhibition elicited increased signal change in various brain regions, including medial frontal areas, compared with response selection. BOLD signal in an area within the right angular gyrus was increased when higher-order categorization was mandated. In addition, signal change during response inhibition varied with categorization requirements in the left inferior temporal gyrus (lIT). lIT-mediated response inhibition when inhibiting the response only required lower-order categorization, but lIT mediated both response selection and inhibition when selecting and inhibiting the response required higher-order categorization. The findings characterized mechanisms mediating response inhibition associated with semantic object categorization in the 'what' visual object memory system.

Chemically stable and reusable nano zero-valent iron/graphite-like carbon nitride nanohybrid for efficient photocatalytic treatment of Cr(VI) and rhodamine B under visible light

NASA Astrophysics Data System (ADS)

Liang, Zhiyu; Wen, Qingjuan; Wang, Xiu; Zhang, Fuwei; Yu, Yan

2016-11-01

Graphite-like carbon nitride (g-C3N4) displays strong potential applications in visible-light photocatalytic for water treatment, but its applications are greatly restricted by high recombination probability of photo-generated electron-hole pairs, as well as a weak reduction ability toward the heavy metals. In this work, we reported the synthesis of nZVI-g-C3N4 nano-hybrid with highly efficiency toward the photodegradation of RhB and Cr(VI) under the visible light irradiation. The nZVI nanoparticles can well be immobilized and dispersed on the surface of g-C3N4 nanosheets by a facile borohydride-reduction method. As-synthesized nZVI-g-C3N4 has an improved photocatalytic activity much better than that of the pure g-C3N4, wherein over 92.9% of Cr(VI) and 99.9% of RhB can be removed by using nZVI-g-C3N4. The nZVI particles not only contributes to the reduction and immobilization of Cr(VI), but also accelerates the photocatalytic degradation efficiency of RhB due to a lower recombination rate of photoexcited holes and electrons. Moreover, nZVI-g-C3N4 preserves superior photodegradation efficiency after five experimental cycles. It can be attributed that nZVI-g-C3N4 photocatalyst is chemically stable, and part of nZVI can be recovered by g-C3N4. We believe that, the composite of nZVI-g-C3N4 reported here could provide guidance for the design of efficient and reusable materials to remove both the organic compounds and heavy metal ions from waste waters.

Magnetically Enhanced Solid-Liquid Separation

NASA Astrophysics Data System (ADS)

Rey, C. M.; Keller, K.; Fuchs, B.

2005-07-01

DuPont is developing an entirely new method of solid-liquid filtration involving the use of magnetic fields and magnetic field gradients. The new hybrid process, entitled Magnetically Enhanced Solid-Liquid Separation (MESLS), is designed to improve the de-watering kinetics and reduce the residual moisture content of solid particulates mechanically separated from liquid slurries. Gravitation, pressure, temperature, centrifugation, and fluid dynamics have dictated traditional solid-liquid separation for the past 50 years. The introduction of an external field (i.e. the magnetic field) offers the promise to manipulate particle behavior in an entirely new manner, which leads to increased process efficiency. Traditional solid-liquid separation typically consists of two primary steps. The first is a mechanical step in which the solid particulate is separated from the liquid using e.g. gas pressure through a filter membrane, centrifugation, etc. The second step is a thermal drying process, which is required due to imperfect mechanical separation. The thermal drying process is over 100-200 times less energy efficient than the mechanical step. Since enormous volumes of materials are processed each year, more efficient mechanical solid-liquid separations can be leveraged into dramatic reductions in overall energy consumption by reducing downstream drying requirements have a tremendous impact on energy consumption. Using DuPont's MESLS process, initial test results showed four very important effects of the magnetic field on the solid-liquid filtration process: 1) reduction of the time to reach gas breakthrough, 2) less loss of solid into the filtrate, 3) reduction of the (solids) residual moisture content, and 4) acceleration of the de-watering kinetics. These test results and their potential impact on future commercial solid-liquid filtration is discussed. New applications can be found in mining, chemical and bioprocesses.

Role of anisotropy in determining stability of electrodeposition at solid-solid interfaces

DOE PAGES

Ahmad, Zeeshan; Viswanathan, Venkatasubramanian

2017-10-24

Here, we investigate the stability of electrodeposition at solid-solid interfaces for materials exhibiting an anisotropic mechanical response. The stability of electrodeposition or resistance to the formation of dendrites is studied within a linear stability analysis. The deformation and stress equations are solved using the Stroh formalism and faithfully recover the boundary conditions at the interface. The stability parameter is used to quantify the stability of different solid-solid interfaces incorporating the full anisotropy of the elastic tensor of the two materials. Our results show a high degree of variability in the stability parameter depending on the crystallographic orientation of the solidsmore » in contact, and point to opportunities for exploiting this effect in developing Li metal anodes.« less

Packaging of solid state devices

DOEpatents

Glidden, Steven C.; Sanders, Howard D.

2006-01-03

A package for one or more solid state devices in a single module that allows for operation at high voltage, high current, or both high voltage and high current. Low thermal resistance between the solid state devices and an exterior of the package and matched coefficient of thermal expansion between the solid state devices and the materials used in packaging enables high power operation. The solid state devices are soldered between two layers of ceramic with metal traces that interconnect the devices and external contacts. This approach provides a simple method for assembling and encapsulating high power solid state devices.

40 CFR Table Jj-4 to Subpart Jj of... - Volatile Solids and Nitrogen Removal through Solids Separation

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Volatile Solids and Nitrogen Removal... Pt. 98, Subpt. JJ, Table JJ-4 Table JJ-4 to Subpart JJ of Part 98—Volatile Solids and Nitrogen Removal through Solids Separation Type of solids separation Volatile solids removal (decimal) Nitrogen...

40 CFR Table Jj-4 to Subpart Jj of... - Volatile Solids and Nitrogen Removal through Solids Separation

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Volatile Solids and Nitrogen Removal... Pt. 98, Subpt. JJ, Table JJ-4 Table JJ-4 to Subpart JJ of Part 98—Volatile Solids and Nitrogen Removal through Solids Separation Type of solids separation Volatile solids removal (decimal) Nitrogen...

40 CFR Table Jj-4 to Subpart Jj of... - Volatile Solids and Nitrogen Removal through Solids Separation

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Volatile Solids and Nitrogen Removal... Pt. 98, Subpt. JJ, Table JJ-4 Table JJ-4 to Subpart JJ of Part 98—Volatile Solids and Nitrogen Removal through Solids Separation Type of solids separation Volatile solids removal (decimal) Nitrogen...

Quinoline 3-sulfonamides inhibit lactate dehydrogenase A and reverse aerobic glycolysis in cancer cells

PubMed Central

2013-01-01

398 cells. Conclusions Rapid chemical inhibition of LDHA by these quinoline 3-sulfonamids led to profound metabolic alterations and impaired cell survival in carcinoma cells making it a compelling strategy for treating solid tumors that rely on aerobic glycolysis for survival. PMID:24280423

Essential Oils and Eugenols Inhibit Biofilm Formation and the Virulence of Escherichia coli O157:H7

PubMed Central

Kim, Yong-Guy; Lee, Jin-Hyung; Gwon, Giyeon; Kim, Soon-Il; Park, Jae Gyu; Lee, Jintae

2016-01-01

Enterohemorrhagic Escherichia coli O157:H7 (EHEC) has caused foodborne outbreaks worldwide and the bacterium forms antimicrobial-tolerant biofilms. We investigated the abilities of various plant essential oils and their components to inhibit biofilm formation by EHEC. Bay, clove, pimento berry oils and their major common constituent eugenol at 0.005% (v/v) were found to markedly inhibit EHEC biofilm formation without affecting planktonic cell growth. In addition, three other eugenol derivatives isoeugenol, 2-methoxy-4-propylphenol, and 4-ethylguaiacol had antibiofilm activity, indicating that the C-1 hydroxyl unit, the C-2 methoxy unit, and C-4 alkyl or alkane chain on the benzene ring of eugenol play important roles in antibiofilm activity. Interestingly, these essential oils and eugenol did not inhibit biofilm formation by three laboratory E. coli K-12 strains that reduced curli fimbriae production. Transcriptional analysis showed that eugenol down-regulated 17 of 28 genes analysed, including curli genes (csgABDFG), type I fimbriae genes (fimCDH) and ler-controlled toxin genes (espD, escJ, escR, and tir), which are required for biofilm formation and the attachment and effacement phenotype. In addition, biocompatible poly(lactic-co-glycolic acid) coatings containing clove oil or eugenol exhibited efficient biofilm inhibition on solid surfaces. In a Caenorhabditis elegans nematode model, clove oil and eugenol attenuated the virulence of EHEC. PMID:27808174

High temperature solid state storage cell

DOEpatents

Rea, Jesse R.; Kallianidis, Milton; Kelsey, G. Stephen

1983-01-01

A completely solid state high temperature storage cell comprised of a solid rechargeable cathode such as TiS.sub.2, a solid electrolyte which remains solid at the high temperature operating conditions of the cell and which exhibits high ionic conductivity at such elevated temperatures such as an electrolyte comprised of lithium iodide, and a solid lithium or other alkali metal alloy anode (such as a lithium-silicon alloy) with 5-50% by weight of said anode being comprised of said solid electrolyte.

Solid state electrochemical current source

DOEpatents

Potanin, Alexander Arkadyevich; Vedeneev, Nikolai Ivanovich

2002-04-30

A cathode and a solid state electrochemical cell comprising said cathode, a solid anode and solid fluoride ion conducting electrolyte. The cathode comprises a metal oxide and a compound fluoride containing at least two metals with different valences. Representative compound fluorides include solid solutions of bismuth fluoride and potassium fluoride; and lead fluoride and potassium fluoride. Representative metal oxides include copper oxide, lead oxide, manganese oxide, vanadium oxide and silver oxide.

Oxygen respirometry to assess stability and maturity of composted municipal solid waste

DOE Office of Scientific and Technical Information (OSTI.GOV)

Iannotti, D.A.; Grebus, M.E.; Toth, B.L.

1994-11-01

The stability and maturity of compost prepared from municipal solid waste (MSW) at a full-scale composting plant was assessed through chemical, physical, and biological assays. Respiration bioassays used to determine stability (O{sub 2} and CO{sub 2} respirometry) were sensitive to process control problems at the composting plant and indicated increasing stability with time. Radish (Raphanus sativus L.) and ryegrass (Lolium perenne L.) growth bioassays revealed that immature compost samples inhibited growth. Growth of ryegrass in potting mix prepared with cured compost not amended with fertilizer was enhanced as compared to a pest control. Garden cress (Lepidium sativum L.) seed germination,more » used as an indicator of phytotoxicity, revealed inhibition of germination at all compost maturity levels. The phytotoxicity was though to be salt-related. Spearman rank-order correlations demonstrated that O{sub 2} respirometry, water-soluble organic C, and the water extract organic C to organic N ratio, significantly correlated with compost age and best indicated an acceptable level of stability. Oxygen respirometry also best predicted the potential for ryegrass growth, and an acceptable level of compost maturity. 31 refs., 4 figs., 5 tabs.« less

Solid-Phase Nucleic Acid Sequence-Based Amplification and Length-Scale Effects during RNA Amplification.

PubMed

Ma, Youlong; Teng, Feiyue; Libera, Matthew

2018-06-05

Solid-phase oligonucleotide amplification is of interest because of possible applications to next-generation sequencing, multiplexed microarray-based detection, and cell-free synthetic biology. Its efficiency is, however, less than that of traditional liquid-phase amplification involving unconstrained primers and enzymes, and understanding how to optimize the solid-phase amplification process remains challenging. Here, we demonstrate the concept of solid-phase nucleic acid sequence-based amplification (SP-NASBA) and use it to study the effect of tethering density on amplification efficiency. SP-NASBA involves two enzymes, avian myeloblastosis virus reverse transcriptase (AMV-RT) and RNase H, to convert tethered forward and reverse primers into tethered double-stranded DNA (ds-DNA) bridges from which RNA - amplicons can be generated by a third enzyme, T7 RNA polymerase. We create microgels on silicon surfaces using electron-beam patterning of thin-film blends of hydroxyl-terminated and biotin-terminated poly(ethylene glycol) (PEG-OH, PEG-B). The tethering density is linearly related to the PEG-B concentration, and biotinylated primers and molecular beacon detection probes are tethered to streptavidin-activated microgels. While SP-NASBA is very efficient at low tethering densities, the efficiency decreases dramatically with increasing tethering density due to three effects: (a) a reduced hybridization efficiency of tethered molecular beacon detection probes; (b) a decrease in T7 RNA polymerase efficiency; (c) inhibition of T7 RNA polymerase activity by AMV-RT.

Inhibition of methane and natural gas hydrate formation by altering the structure of water with amino acids.

PubMed

Sa, Jeong-Hoon; Kwak, Gye-Hoon; Han, Kunwoo; Ahn, Docheon; Cho, Seong Jun; Lee, Ju Dong; Lee, Kun-Hong

2016-08-16

Natural gas hydrates are solid hydrogen-bonded water crystals containing small molecular gases. The amount of natural gas stored as hydrates in permafrost and ocean sediments is twice that of all other fossil fuels combined. However, hydrate blockages also hinder oil/gas pipeline transportation, and, despite their huge potential as energy sources, our insufficient understanding of hydrates has limited their extraction. Here, we report how the presence of amino acids in water induces changes in its structure and thus interrupts the formation of methane and natural gas hydrates. The perturbation of the structure of water by amino acids and the resulting selective inhibition of hydrate cage formation were observed directly. A strong correlation was found between the inhibition efficiencies of amino acids and their physicochemical properties, which demonstrates the importance of their direct interactions with water and the resulting dissolution environment. The inhibition of methane and natural gas hydrate formation by amino acids has the potential to be highly beneficial in practical applications such as hydrate exploitation, oil/gas transportation, and flow assurance. Further, the interactions between amino acids and water are essential to the equilibria and dynamics of many physical, chemical, biological, and environmental processes.

Inhibition of methane and natural gas hydrate formation by altering the structure of water with amino acids

PubMed Central

Sa, Jeong-Hoon; Kwak, Gye-Hoon; Han, Kunwoo; Ahn, Docheon; Cho, Seong Jun; Lee, Ju Dong; Lee, Kun-Hong

2016-01-01

Natural gas hydrates are solid hydrogen-bonded water crystals containing small molecular gases. The amount of natural gas stored as hydrates in permafrost and ocean sediments is twice that of all other fossil fuels combined. However, hydrate blockages also hinder oil/gas pipeline transportation, and, despite their huge potential as energy sources, our insufficient understanding of hydrates has limited their extraction. Here, we report how the presence of amino acids in water induces changes in its structure and thus interrupts the formation of methane and natural gas hydrates. The perturbation of the structure of water by amino acids and the resulting selective inhibition of hydrate cage formation were observed directly. A strong correlation was found between the inhibition efficiencies of amino acids and their physicochemical properties, which demonstrates the importance of their direct interactions with water and the resulting dissolution environment. The inhibition of methane and natural gas hydrate formation by amino acids has the potential to be highly beneficial in practical applications such as hydrate exploitation, oil/gas transportation, and flow assurance. Further, the interactions between amino acids and water are essential to the equilibria and dynamics of many physical, chemical, biological, and environmental processes. PMID:27526869

Inhibition of methane and natural gas hydrate formation by altering the structure of water with amino acids

NASA Astrophysics Data System (ADS)

Sa, Jeong-Hoon; Kwak, Gye-Hoon; Han, Kunwoo; Ahn, Docheon; Cho, Seong Jun; Lee, Ju Dong; Lee, Kun-Hong

2016-08-01

Natural gas hydrates are solid hydrogen-bonded water crystals containing small molecular gases. The amount of natural gas stored as hydrates in permafrost and ocean sediments is twice that of all other fossil fuels combined. However, hydrate blockages also hinder oil/gas pipeline transportation, and, despite their huge potential as energy sources, our insufficient understanding of hydrates has limited their extraction. Here, we report how the presence of amino acids in water induces changes in its structure and thus interrupts the formation of methane and natural gas hydrates. The perturbation of the structure of water by amino acids and the resulting selective inhibition of hydrate cage formation were observed directly. A strong correlation was found between the inhibition efficiencies of amino acids and their physicochemical properties, which demonstrates the importance of their direct interactions with water and the resulting dissolution environment. The inhibition of methane and natural gas hydrate formation by amino acids has the potential to be highly beneficial in practical applications such as hydrate exploitation, oil/gas transportation, and flow assurance. Further, the interactions between amino acids and water are essential to the equilibria and dynamics of many physical, chemical, biological, and environmental processes.

Sparse Coding and Lateral Inhibition Arising from Balanced and Unbalanced Dendrodendritic Excitation and Inhibition

PubMed Central

Migliore, Michele; Hines, Michael L.; Shepherd, Gordon M.

2014-01-01

The precise mechanism by which synaptic excitation and inhibition interact with each other in odor coding through the unique dendrodendritic synaptic microcircuits present in olfactory bulb is unknown. Here a scaled-up model of the mitral–granule cell network in the rodent olfactory bulb is used to analyze dendrodendritic processing of experimentally determined odor patterns. We found that the interaction between excitation and inhibition is responsible for two fundamental computational mechanisms: (1) a balanced excitation/inhibition in strongly activated mitral cells, leading to a sparse representation of odorant input, and (2) an unbalanced excitation/inhibition (inhibition dominated) in surrounding weakly activated mitral cells, leading to lateral inhibition. These results suggest how both mechanisms can carry information about the input patterns, with optimal level of synaptic excitation and inhibition producing the highest level of sparseness and decorrelation in the network response. The results suggest how the learning process, through the emergent development of these mechanisms, can enhance odor representation of olfactory bulb. PMID:25297097

Effects of polymer type and storage relative humidity on the kinetics of felodipine crystallization from amorphous solid dispersions.

PubMed

Rumondor, Alfred C F; Stanford, Lindsay A; Taylor, Lynne S

2009-12-01

The objective of this study was to investigate the effects of polymer type and storage relative humidity (RH) on the crystallization kinetics of felodipine from amorphous solid dispersions. Crystallization of the model drug felodipine from amorphous solid dispersion samples containing poly(vinyl pyrrolidone) (PVP) and hypromellose acetate succinate (HPMCAS) were evaluated. Samples at three different drug-polymer weight ratios (10, 25, and 50 wt. % polymer) were prepared and stored at six different RHs (0%, 32%, 52% or 66%, 75%, 86%, and 93%). Periodically, the fraction of the drug that had crystallized from the samples was quantified using powder X-ray diffractometry (PXRD). Felodipine crystallization rates from PVP-containing dispersions were found to be very sensitive to changes in storage RH, while crystallization rates from HPMCAS-containing dispersions were not. PVP and HPMCAS were similar in terms of their ability to inhibit crystallization at low RH, but when the storage RH was increased to 75% or above, felodipine crystallization from PVP-containing solid dispersions proceeded much faster. It is hypothesized that this trend was caused by moisture-induced drug-polymer immiscibility in PVP-felodipine system. For PVP-containing solid dispersion samples stored at 75% RH and above, crystallization of the model drug felodipine seemed to approach a kinetic plateau, whereby a fraction of the drug still remained amorphous even after storage for 500 days or more. The physical stability of solid dispersions as a function of RH is highly dependent on the polymer used to form the solid dispersion, with PVP-containing dispersions being much less physically stable at high RH than HPMCAS-containing dispersions.

Should we stop thinking about inhibition? Searching for individual and age differences in inhibition ability.

PubMed

Rey-Mermet, Alodie; Gade, Miriam; Oberauer, Klaus

2018-04-01

Inhibition is often conceptualized as a unitary construct reflecting the ability to ignore and suppress irrelevant information. At the same time, it has been subdivided into inhibition of prepotent responses (i.e., the ability to stop dominant responses) and resistance to distracter interference (i.e., the ability to ignore distracting information). The present study investigated the unity and diversity of inhibition as a psychometric construct, and tested the hypothesis of an inhibition deficit in older age. We measured inhibition in young and old adults with 11 established laboratory tasks: antisaccade, stop-signal, color Stroop, number Stroop, arrow flanker, letter flanker, Simon, global-local, positive and negative compatibility tasks, and n-2 repetition costs in task switching. In both age groups, the inhibition measures from individual tasks had good reliabilities, but correlated only weakly among each other. Structural equation modeling identified a 2-factor model with factors for inhibition of prepotent responses and resistance to distracter interference. Older adults scored worse in the inhibition of prepotent response, but better in the resistance to distracter interference. However, the model had low explanatory power. Together, these findings call into question inhibition as a psychometric construct and the hypothesis of an inhibition deficit in older age. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Charge transfer kinetics at the solid-solid interface in porous electrodes

NASA Astrophysics Data System (ADS)

Bai, Peng; Bazant, Martin Z.

2014-04-01

Interfacial charge transfer is widely assumed to obey the Butler-Volmer kinetics. For certain liquid-solid interfaces, the Marcus-Hush-Chidsey theory is more accurate and predictive, but it has not been applied to porous electrodes. Here we report a simple method to extract the charge transfer rates in carbon-coated LiFePO4 porous electrodes from chronoamperometry experiments, obtaining curved Tafel plots that contradict the Butler-Volmer equation but fit the Marcus-Hush-Chidsey prediction over a range of temperatures. The fitted reorganization energy matches the Born solvation energy for electron transfer from carbon to the iron redox site. The kinetics are thus limited by electron transfer at the solid-solid (carbon-LixFePO4) interface rather than by ion transfer at the liquid-solid interface, as previously assumed. The proposed experimental method generalizes Chidsey’s method for phase-transforming particles and porous electrodes, and the results show the need to incorporate Marcus kinetics in modelling batteries and other electrochemical systems.

Solid-solid phase change thermal storage application to space-suit battery pack

NASA Astrophysics Data System (ADS)

Son, Chang H.; Morehouse, Jeffrey H.

1989-01-01

High cell temperatures are seen as the primary safety problem in the Li-BCX space battery. The exothermic heat from the chemical reactions could raise the temperature of the lithium electrode above the melting temperature. Also, high temperature causes the cell efficiency to decrease. Solid-solid phase-change materials were used as a thermal storage medium to lower this battery cell temperature by utilizing their phase-change (latent heat storage) characteristics. Solid-solid phase-change materials focused on in this study are neopentyl glycol and pentaglycerine. Because of their favorable phase-change characteristics, these materials appear appropriate for space-suit battery pack use. The results of testing various materials are reported as thermophysical property values, and the space-suit battery operating temperature is discussed in terms of these property results.

Contact Dependence and Velocity Crossover in Friction between Microscopic Solid/Solid Contacts.

PubMed

McGraw, Joshua D; Niguès, Antoine; Chennevière, Alexis; Siria, Alessandro

2017-10-11

Friction at the nanoscale differs markedly from that between surfaces of macroscopic extent. Characteristically, the velocity dependence of friction between apparent solid/solid contacts can strongly deviate from the classically assumed velocity independence. Here, we show that a nondestructive friction between solid tips with radius on the scale of hundreds of nanometers and solid hydrophobic self-assembled monolayers has a strong velocity dependence. Specifically, using laterally oscillating quartz tuning forks, we observe a linear scaling in the velocity at the lowest accessed velocities, typically hundreds of micrometers per second, crossing over into a logarithmic velocity dependence. This crossover is consistent with a general multicontact friction model that includes thermally activated breaking of the contacts at subnanometric elongation. We find as well a strong dependence of the friction on the dimensions of the frictional probe.

Well-Coupled Nanohybrids Obtained by Component-Controlled Synthesis and in Situ Integration of Mn xPd y Nanocrystals on Vulcan Carbon for Electrocatalytic Oxygen Reduction.

PubMed

Lu, Yanan; Zhao, Shulin; Yang, Rui; Xu, Dongdong; Yang, Jing; Lin, Yue; Shi, Nai-En; Dai, Zhihui; Bao, Jianchun; Han, Min

2018-03-07

Development of cheap, highly active, and robust bimetallic nanocrystal (NC)-based nanohybrid (NH) electrocatalysts for oxygen reduction reaction (ORR) is helpful for advancing fuel cells or other renewable energy technologies. Here, four kinds of well-coupled Mn x Pd y (MnPd 3 , MnPd-Pd, Mn 2 Pd 3 , Mn 2 Pd 3 -Mn 11 Pd 21 )/C NHs have been synthesized by in situ integration of Mn x Pd y NCs with variable component ratios on pretreated Vulcan XC-72 C using the solvothermal method accompanied with annealing under Ar/H 2 atmosphere and used as electrocatalysts for ORR. Among them, the MnPd 3 /C NHs possess the unique "half-embedded and half-encapsulated" interfaces and exhibit the highest catalytic activity, which can compete with some currently reported non-Pt catalysts (e.g., Ag-Co nanoalloys, Pd 2 NiAg NCs, PdCo/N-doped porous C, G-Cu 3 Pd nanocomposites, etc.), and close to commercial Pt/C. Electrocatalytic dynamic measurements disclose that their ORR mechanism abides by the direct 4e - pathway. Moreover, their durability and methanol-tolerant capability are much higher than that of Pt/C. As revealed by spectroscopic and electrochemical analyses, the excellent catalytic performance of MnPd 3 /C NHs results from the proper component ratio of Mn and Pd and the strong interplay of their constituents, which not only facilitate to optimize the d-band center or the electronic structure of Pd but also induce the phase transformation of MnPd 3 active components and enhance their conductivity or interfacial electron transfer dynamics. This work demonstrates that MnPd 3 /C NHs are promising methanol-tolerant cathode electrocatalysts that may be employed in fuel cells or other renewable energy option.

Sunitinib‐Induced Cardiotoxicity Is Mediated by Off‐Target Inhibition of AMP‐Activated Protein Kinase

PubMed Central

Kerkela, Risto; Woulfe, Kathleen C.; Durand, Jean‐Bernard; Vagnozzi, Ronald; Kramer, David; Chu, Tammy F.; Beahm, Cara; Chen, Ming Hui; Force, Thomas

2009-01-01

Abstract Tyrosine kinase inhibitors (TKIs) are transforming the treatment of patients with malignancies. One such agent, sunitinib (Sutent, Pfizer, New York, NY, USA), has demonstrated activity against a variety of solid tumors. Sunitinib is “multitargeted,” inhibiting growth factor receptors that regulate both tumor angiogenesis and tumor cell survival. However, cardiac dysfunction has been associated with its use. Identification of the target of sunitinib‐associated cardiac dysfunction could guide future drug design to reduce toxicity while preserving anticancer activity. Herein we identify severe mitochondrial structural abnormalities in the heart of a patient with sunitinib‐induced heart failure. In cultured cardiomyocytes, sunitinib induces loss of mitochondrial membrane potential and energy rundown. Despite the latter, 5′ adenosine monophosphate‐activated protein kinase (AMPK) activity, which should be increased in the setting of energy compromise, is reduced in hearts of sunitinib‐treated mice and cardiomyocytes in culture, and this is due to direct inhibition of AMPK by sunitinib. Critically, we find that adenovirus‐mediated gene transfer of an activated mutant of AMPK reduces sunitinib‐induced cell death. Our findings suggest AMPK inhibition plays a central role in sunitinib cardiomyocyte toxicity, highlighting the potential of off‐target effects of TKIs contributing to cardiotoxicity. While multitargeting can enhance tumor cell killing, this must be balanced against the potential increased risk of cardiac dysfunction. PMID:20376335

Effect of deoxyribozymes targeting c-Jun on solid tumor growth and angiogenesis in rodents.

PubMed

Zhang, Guishui; Dass, Crispin R; Sumithran, Eric; Di Girolamo, Nick; Sun, Lun-Quan; Khachigian, Levon M

2004-05-05

The basic region-leucine zipper protein c-Jun has been linked to cell proliferation, transformation, and apoptosis. However, a direct role for c-Jun in angiogenesis has not been shown. We used human microvascular endothelial cells (HMEC-1) transfected with a DNAzyme targeting the c-Jun mRNA (Dz13), related oligonucleotides, or vehicle in in vitro models of microvascular endothelial cell proliferation, migration, chemoinvasion, and tubule formation, a rat model of corneal neovascularization, and a mouse model of solid tumor growth and vascular endothelial growth factor (VEGF)-induced angiogenesis. All statistical tests were two-sided. Compared with mock-transfected cells, HMEC-1 cells transfected with Dz13 expressed less c-Jun protein and possessed lower DNA-binding activity. Dz13 blocked endothelial cell proliferation, migration, chemoinvasion, and tubule formation. Dz13 inhibited the endothelial cell expression and proteolytic activity of MMP-2, a c-Jun-dependent gene. Dz13 inhibited VEGF-induced neovascularization in the rat cornea compared with vehicle control (Dz13 versus vehicle: 4.0 neovessels versus 30.7 neovessels, difference = 26.7 neovessels; P =.004; area occupied by new blood vessels for Dz13 versus vehicle: 0.35 mm2 versus 1.52 mm2, difference = 1.17 mm2; P =.005) as well as solid melanoma growth in mice (Dz13 versus vehicle at 14 days: 108 mm3 versus 283 mm3, difference = 175 mm3; P =.006) with greatly reduced vascular density (Dz13 versus vehicle: 30% versus 100%, difference = 70%; P<.001). DNAzymes targeting c-Jun may have therapeutic potential as inhibitors of tumor angiogenesis and growth.

Different Efficiency of Liposomal Forms with Hydrophilic and Hydrophobic Antitumor Agents in Relation to Solid Transplants of Mouse Tumor and Its Metastases in the Liver.

PubMed

Popova, N A; Kaledin, V I; Nikolin, V P; Bogdanova, L A; Morozkova, T S; Tornuev, Yu V

2016-10-01

Experiments were performed on the model of transplanted mouse tumor with high incidence of liver metastases. Hydrophilic drug cycloplatam (injected intravenously in liposomes) was more potent than "free cycloplatam" (injected intravenously or intraperitoneally in physiological saline) in inhibiting the growth of natural and experimental metastases in the liver. By contrast, liposomal cycloplatam had lower efficiency than free cycloplatam in suppressing the growth of solid tumor. Liposomal and free cortifen (hydrophobic hormonal cytostatic) produced nearly the same effects on solid tumor growth. Our results suggest that liposomal forms of hydrophobic compounds producing nonselective effect on tumor cells (e.g., actinomycin D or Cosmegen), should not have advantages over free forms.

Efficient inhibition of EGFR signaling and of tumour growth by antagonistic anti-EFGR Nanobodies.

PubMed

Roovers, Rob C; Laeremans, Toon; Huang, Lieven; De Taeye, Severine; Verkleij, Arie J; Revets, Hilde; de Haard, Hans J; van Bergen en Henegouwen, Paul M P

2007-03-01

The development of a number of different solid tumours is associated with over-expression of ErbB1, or the epidermal growth factor receptor (EGFR), and this over-expression is often correlated with poor prognosis of patients. Therefore, this receptor tyrosine kinase is considered to be an attractive target for antibody-based therapy. Indeed, antibodies to the EGFR have already proven their value for the treatment of several solid tumours, especially in combination with chemotherapeutic treatment regimens. Variable domains of camelid heavy chain-only antibodies (called Nanobodies) have superior properties compared with classical antibodies in that they are small, very stable, easy to produce in large quantities and easy to re-format into multi-valent or multi-specific proteins. Furthermore, they can specifically be selected for a desired function by phage antibody display. In this report, we describe the successful selection and the characterisation of antagonistic anti-EGFR Nanobodies. By using a functional selection strategy, Nanobodies that specifically competed for EGF binding to the EGFR were isolated from "immune" phage Nanobody repertoires. The selected antibody fragments were found to efficiently inhibit EGF binding to the EGFR without acting as receptor agonists themselves. In addition, they blocked EGF-mediated signalling and EGF-induced cell proliferation. In an in vivo murine xenograft model, the Nanobodies were effective in delaying the outgrowth of A431-derived solid tumours. This is the first report describing the successful use of untagged Nanobodies for the in vivo treatment of solid tumours. The results show that functional phage antibody selection, coupled to the rational design of Nanobodies, permits the rapid development of novel anti-cancer antibody-based therapeutics.

Identification of compounds bound to suspended solids causing sub-lethal toxic effects in Daphnia magna. A field study on re-suspended particles during river floods in Ebro River.

PubMed

Rivetti, Claudia; Gómez-Canela, Cristian; Lacorte, Silvia; Díez, Sergi; Lázaro, Wilkinson L; Barata, Carlos

2015-04-01

Identifying chemicals causing adverse effects in organisms present in water remains a challenge in environmental risk assessment. This study aimed to assess and identify toxic compounds bound to suspended solids re-suspended during a prolonged period of flushing flows in the lower part of Ebro River (NE, Spain). This area is contaminated with high amounts of organochlorine and mercury sediment wastes. Chemical characterization of suspended material was performed by solid phase extraction using a battery of non-polar and polar solvents and analyzed by GC-MS/MS and LC-MS/MS. Mercury content was also determined for all sites. Post-exposure feeding rates of Daphnia magna were used to assess toxic effects of whole and filtered water samples and of re-constituted laboratory water with re-suspended solid fractions. Organochlorine and mercury residues in the water samples increased from upstream to downstream locations. Conversely, toxic effects were greater at the upstream site than downstream of the superfund Flix reservoir. A further analysis of the suspended solid fraction identified a toxic component eluted within the 80:20 methanol:water fraction. Characterization of that toxic component fraction by LC-MS/MS identified the phytotoxin anatoxin-a, whose residue levels were correlated with observed feeding inhibition responses. Further feeding inhibition assays conducted in the lab using anatoxin-a produced from Planktothrix agardhii, a filamentous cyanobacteria, confirmed field results. This study provides evidence that in real field situation measured contaminant residues do not always agree with toxic effects. Copyright © 2015 Elsevier B.V. All rights reserved.

Solid-on-solid contact in a sphere-wall collision in a viscous fluid

NASA Astrophysics Data System (ADS)

Birwa, Sumit Kumar; Rajalakshmi, G.; Govindarajan, Rama; Menon, Narayanan

2018-04-01

We study experimentally the collision between a sphere falling through a viscous fluid and a solid plate below. It is known that there is a well-defined threshold Stokes number above which the sphere rebounds from such a collision. Our experiment tests for direct contact between the colliding bodies and, contrary to prior theoretical predictions, shows that solid-on-solid contact occurs even for Stokes numbers just above the threshold for rebounding. The dissipation is fluid dominated, though details of the contact mechanics depend on the surface and bulk properties of the solids. Our experiments and a model calculation indicate that mechanical contact between the two colliding objects is generic and will occur for any realistic surface roughness.

Inhibition of ethylene production by putrescine alleviates aluminium-induced root inhibition in wheat plants.

PubMed

Yu, Yan; Jin, Chongwei; Sun, Chengliang; Wang, Jinghong; Ye, Yiquan; Zhou, Weiwei; Lu, Lingli; Lin, Xianyong

2016-01-08

Inhibition of root elongation is one of the most distinct symptoms of aluminium (Al) toxicity. Although putrescine (Put) has been identified as an important signaling molecule involved in Al tolerance, it is yet unknown how Put mitigates Al-induced root inhibition. Here, the possible mechanism was investigated by using two wheat genotypes differing in Al resistance: Al-tolerant Xi Aimai-1 and Al-sensitive Yangmai-5. Aluminium caused more root inhibition in Yangmai-5 and increased ethylene production at the root apices compared to Xi Aimai-1, whereas the effects were significantly reversed by ethylene biosynthesis inhibitors. The simultaneous exposure of wheat seedlings to Al and ethylene donor, ethephon, or ethylene biosynthesis precursor, 1-aminocyclopropane-1-carboxylic acid (ACC), increased ethylene production and aggravated root inhibition, which was more pronounced in Xi Aimai-1. In contrast, Put treatment decreased ethylene production and alleviated Al-induced root inhibition in both genotypes, and the effects were more conspicuous in Yangmai-5. Furthermore, our results indicated that Al-induced ethylene production was mediated by ACC synthase (ACS) and ACC oxidase, and that Put decreased ethylene production by inhibiting ACS. Altogether, these findings indicate that ethylene is involved in Al-induced root inhibition and this process could be alleviated by Put through inhibiting ACS activity.

Composite Solid Electrolyte For Lithium Cells

NASA Technical Reports Server (NTRS)

Peled, Emmanuel; Nagasubramanian, Ganesan; Halpert, Gerald; Attia, Alan I.

1994-01-01

Composite solid electrolyte material consists of very small particles, each coated with thin layer of Lil, bonded together with polymer electrolyte or other organic binder. Material offers significant advantages over other solid electrolytes in lithium cells and batteries. Features include high ionic conductivity and strength. Composite solid electrolyte expected to exhibit flexibility of polymeric electrolytes. Polymer in composite solid electrolyte serves two purposes: used as binder alone, conduction taking place only in AI2O3 particles coated with solid Lil; or used as both binder and polymeric electrolyte, providing ionic conductivity between solid particles that it binds together.

Sonic-Hedgehog pathway inhibition normalizes desmoplastic tumor microenvironment to improve chemo- and nanotherapy

PubMed Central

Voutouri, Chrysovalantis; Kalli, Maria; Pirentis, Athanassios P.; Stylianopoulos, Triantafyllos

2017-01-01

Targeting the rich extracellular matrix of desmoplastic tumors has been successfully shown to normalize collagen and hyaluronan levels and re-engineer intratumoral mechanical forces, improving tumor perfusion and chemotherapy. As far as targeting the abundant cancer-associated fibroblasts (CAFs) in desmoplastic tumors is concerned, while both pharmacologic inhibition of the sonic-hedgehog pathway and genetic depletion of fibroblasts have been employed in pancreatic cancers, the results between the two methods have been contradictory. In this study, we employed vismodegib to inhibit the sonic-hedgehog pathway with the aim to i) elucidate the mechanism of how CAFs depletion improves drug delivery, ii) extent and evaluate the potential use of sonic-hedgehog inhibitors to breast cancers, and iii) investigate whether sonic-hedgehog inhibition improves not only chemotherapy, but also the efficacy of the most commonly used breast cancer nanomedicines, namely Abraxane® and Doxil®. We found that treatment with vismodegib normalizes the tumor microenvironment by reducing the proliferative CAFs and in cases the levels of collagen and hyaluronan. These modulations re-engineered the solid and fluid stresses in the tumors, improving blood vessel functionality. As a result, the delivery and efficacy of chemotherapy was improved in two models of pancreatic cancer. Additionally, vismodegib treatment significantly improved the efficacy of both Abraxane and Doxil in xenograft breast tumors. Our results suggest the use of vismodegib, and sonic hedgehog inhibitors in general, to enhance cancer chemo- and nanotherapy. PMID:28662901

Continuum approaches for describing solid-gas and solid-liquid flow

DOE Office of Scientific and Technical Information (OSTI.GOV)

Diamond, P.; Harvey, J.; Levine, H.

Two-phase continuum models have been used to describe the multiphase flow properties of solid-gas and solid-liquid mixtures. The approach is limited in that it requires many fitting functions and parameters to be determined empirically, and it does not provide natural explanations for some of the qualitative behavior of solid-fluid flow. In this report, we explore a more recent single-phase continuum model proposed by Jenkins and Savage to describe granular flow. Jenkins and McTigue have proposed a modified model to describe the flow of dense suspensions, and hence, many of our results can be straight-forwardly extended to this flow regime asmore » well. The solid-fluid mixture is treated as a homogeneous, compressible fluid in which the particle fluctuations about the mean flow are described in terms of an effective temperature. The particle collisions are treated as inelastic. After an introduction in which we briefly comment on the present status of the field, we describe the details of the single-phase continuum model and analyze the microscopic and macroscopic flow conditions required for the approach to be valid. We then derive numerous qualitative predictions which can be empirically verified in small-scale experiments: The flow profiles are computed for simple boundary conditions, plane Couette flow and channel flow. Segregaion effects when there are two (or more) particle size are considered. The acoustic dispersion relation is derived and shown to predict that granular flow is supersonic. We point out that the analysis of flow instabilities is complicated by the finite compressibility of the solid-fluid mixture. For example, the large compressibility leads to interchange (Rayleigh-Taylor instabilities) in addition to the usual angular momentum interchange in standard (cylindrical) Couette flow. We conclude by describing some of the advantages and limitations of experimental techniques that might be used to test predictions for solid-fluid flow. 19 refs.« less

Iminosugars Inhibit Dengue Virus Production via Inhibition of ER Alpha-Glucosidases--Not Glycolipid Processing Enzymes.

PubMed

Sayce, Andrew C; Alonzi, Dominic S; Killingbeck, Sarah S; Tyrrell, Beatrice E; Hill, Michelle L; Caputo, Alessandro T; Iwaki, Ren; Kinami, Kyoko; Ide, Daisuke; Kiappes, J L; Beatty, P Robert; Kato, Atsushi; Harris, Eva; Dwek, Raymond A; Miller, Joanna L; Zitzmann, Nicole

2016-03-01

It has long been thought that iminosugar antiviral activity is a function of inhibition of endoplasmic reticulum-resident α-glucosidases, and on this basis, many iminosugars have been investigated as therapeutic agents for treatment of infection by a diverse spectrum of viruses, including dengue virus (DENV). However, iminosugars are glycomimetics possessing a nitrogen atom in place of the endocyclic oxygen atom, and the ubiquity of glycans in host metabolism suggests that multiple pathways can be targeted via iminosugar treatment. Successful treatment of patients with glycolipid processing defects using iminosugars highlights the clinical exploitation of iminosugar inhibition of enzymes other than ER α-glucosidases. Evidence correlating antiviral activity with successful inhibition of ER glucosidases together with the exclusion of alternative mechanisms of action of iminosugars in the context of DENV infection is limited. Celgosivir, a bicyclic iminosugar evaluated in phase Ib clinical trials as a therapeutic for the treatment of DENV infection, was confirmed to be antiviral in a lethal mouse model of antibody-enhanced DENV infection. In this study we provide the first evidence of the antiviral activity of celgosivir in primary human macrophages in vitro, in which it inhibits DENV secretion with an EC50 of 5 μM. We further demonstrate that monocyclic glucose-mimicking iminosugars inhibit isolated glycoprotein and glycolipid processing enzymes and that this inhibition also occurs in primary cells treated with these drugs. By comparison to bicyclic glucose-mimicking iminosugars which inhibit glycoprotein processing but do not inhibit glycolipid processing and galactose-mimicking iminosugars which do not inhibit glycoprotein processing but do inhibit glycolipid processing, we demonstrate that inhibition of endoplasmic reticulum-resident α-glucosidases, not glycolipid processing, is responsible for iminosugar antiviral activity against DENV. Our data suggest that

Improving the dissolution rate of poorly water soluble drug by solid dispersion and solid solution: pros and cons.

PubMed

Chokshi, Rina J; Zia, Hossein; Sandhu, Harpreet K; Shah, Navnit H; Malick, Waseem A

2007-01-01

The solid dispersions with poloxamer 188 (P188) and solid solutions with polyvinylpyrrolidone K30 (PVPK30) were evaluated and compared in an effort to improve aqueous solubility and bioavailability of a model hydrophobic drug. All preparations were characterized by differential scanning calorimetry, powder X-ray diffraction, intrinsic dissolution rates, and contact angle measurements. Accelerated stability studies also were conducted to determine the effects of aging on the stability of various formulations. The selected solid dispersion and solid solution formulations were further evaluated in beagle dogs for in vivo testing. Solid dispersions were characterized to show that the drug retains its crystallinity and forms a two-phase system. Solid solutions were characterized to be an amorphous monophasic system with transition of crystalline drug to amorphous state. The evaluation of the intrinsic dissolution rates of various preparations indicated that the solid solutions have higher initial dissolution rates compared with solid dispersions. However, after storage at accelerated conditions, the dissolution rates of solid solutions were lower due to partial reversion to crystalline form. The drug in solid dispersion showed better bioavailability in comparison to solid solution. Therefore, considering physical stability and in vivo study results, the solid dispersion was the most suitable choice to improve dissolution rates and hence the bioavailability of the poorly water soluble drug.

Theoretic criteria for antibody penetration into solid tumors and micrometastases.

PubMed

Thurber, Greg M; Zajic, Stefan C; Wittrup, K Dane

2007-06-01

Targeting tumors with antibody-based therapeutics is a complex task presenting multiple kinetic barriers. Antibody internalization and clearance inhibit uptake both in solid tumors, limited by tumor vascular permeability, and in micrometastases, limited by diffusion. A modeling exercise is used to introduce 2 simple criteria that must be less than unity for saturation of both tumors and micrometastases. The clearance modulus and the Thiele modulus are ratios of the plasma clearance rate and antibody catabolism, respectively, to the tumor tissue penetration rate. Even low rates of antigen internalization from constitutive membrane turnover can significantly retard antibody penetration. Rapid clearance of single-chain variable fragments also hinders uptake, often more than counterbalancing their more rapid extravasation and diffusion. The model illustrates that with the large resistance from the tumor capillary, antibodies may be more suitable for targeting micrometastases than vascularized tumors.

Selective inhibition of KCa3.1 channels mediates adenosine regulation of the motility of human T cells.

PubMed

Chimote, Ameet A; Hajdu, Peter; Kucher, Vladimir; Boiko, Nina; Kuras, Zerrin; Szilagyi, Orsolya; Yun, Yeo-Heung; Conforti, Laura

2013-12-15

Adenosine, a purine nucleoside, is present at high concentrations in tumors, where it contributes to the failure of immune cells to eliminate cancer cells. The mechanisms responsible for the immunosuppressive properties of adenosine are not fully understood. We tested the hypothesis that adenosine's immunosuppressive functions in human T lymphocytes are in part mediated via modulation of ion channels. The activity of T lymphocytes relies on ion channels. KCa3.1 and Kv1.3 channels control cytokine release and, together with TRPM7, regulate T cell motility. Adenosine selectively inhibited KCa3.1, but not Kv1.3 and TRPM7, in activated human T cells. This effect of adenosine was mainly mediated by A2A receptors, as KCa3.1 inhibition was reversed by SCH58261 (selective A2A receptor antagonist), but not by MRS1754 (A2B receptor antagonist), and it was mimicked by the A2A receptor agonist CGS21680. Furthermore, it was mediated by the cAMP/protein kinase A isoform (PKAI) signaling pathway, as adenylyl-cyclase and PKAI inhibition prevented adenosine effect on KCa3.1. The functional implication of the effect of adenosine on KCa3.1 was determined by measuring T cell motility on ICAM-1 surfaces. Adenosine and CGS21680 inhibited T cell migration. Comparable effects were obtained by KCa3.1 blockade with TRAM-34. Furthermore, the effect of adenosine on cell migration was abolished by pre-exposure to TRAM-34. Additionally, adenosine suppresses IL-2 secretion via KCa3.1 inhibition. Our data indicate that adenosine inhibits KCa3.1 in human T cells via A2A receptor and PKAI, thereby resulting in decreased T cell motility and cytokine release. This mechanism is likely to contribute to decreased immune surveillance in solid tumors.

Lyophilization -Solid Waste Treatment

NASA Technical Reports Server (NTRS)

Litwiller, Eric; Flynn, Michael; Fisher, John; Reinhard, Martin

2004-01-01

This paper discusses the development of a solid waste treatment system that has been designed for a Mars transit exploration mission. The technology described is an energy-efficient lyophilization technique that is designed to recover water from spacecraft solid wastes. Candidate wastes include feces, concentrated brines from water processors, and other solid wastes that contain free water. The system is designed to operate as a stand-alone process or to be integrated into the International Space Station Waste Collection System. In the lyophilization process, water in an aqueous waste is frozen and then sublimed, separating the waste into a dried solid material and liquid water. The sublimed water is then condensed in a solid ice phase and then melted to generate a liquid product. In the subject system the waste solids are contained within a 0.2 micron bio-guard bag and after drying are removed from the system and stored in a secondary container. This technology is ideally suited to applications such as the Mars Reference Mission, where water recovery rates approaching 100% are desirable but production of CO2 is not. The system is designed to minimize power consumption through the use of thermoelectric heat pumps. The results of preliminary testing of a prototype system and testing of the final configuration are provided. A mathematical model of the system is also described.

Functionalized magnetic nanoparticles for the decontamination of water polluted with cesium

NASA Astrophysics Data System (ADS)

Helal, Ahmed S.; Decorse, Philippe; Perruchot, Christian; Novak, Sophie; Lion, Claude; Ammar, Souad; El Hage Chahine, Jean-Michel; Hémadi, Miryana

2016-05-01

Magnetic nanoparticles are attracting considerable interest because of their potential applications in practically all fields of science and technology, including the removal of heavy metals from contaminated waters. It is, therefore, of great importance to adapt the surfaces of these nanoparticles according to the application. In this work advanced nanoparticles (NPs) with well-tailored surface functionalities were synthesized using the polyol method. The efficiency of a chelating agent, succinyl-β-cyclodextrin (SBCD), was first investigated spectrophotometrically and by Isothermal Titration Calorimetry (ITC). SBCD was then grafted onto nanoparticles previously functionalized with 3-aminopropyl triethoxsilane (NP-APTES). The resulting NP-SBCD system was then incubated with a solution of cesium. After magnetic separation, the solid residue was removed from the supernatant and characterized by X-Ray Photoelectron spectrometry (XPS), X-Ray Fluorescence spectrometry (XRF) and Superconducting QUantum Interference Device (SQUID) magnetometry. These characterizations show the presence of cesium in the solid residue, which indicates Cs uptake by the NP-SBCD system. This nanohybrid system constitutes a promising model for heavy metal decontamination.

CdS-pillared CoAl-layered double hydroxide nanosheets with superior photocatalytic activity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qiu, Yanqiang; Lin, Bizhou, E-mail: bzlin@hqu.edu.cn; Jia, Fangcao

Graphical abstract: - Highlights: • CdS nanocrystals were intercalated into CoAl-LDH interlayer. • The nanohybrid display superior visible-light photocatalytic activity. • A photoexcitation model for the pillared heterostructured system was proposed. - Abstract: A new nanohybrid was synthesized by mixing the positively charged 2D nanosheets of CoAl-layered double hydroxide (CoAl-LDH) and the negatively charged CdS nanosol suspensions. It was revealed that the CdS nanoparticles were intercalated into the interlayer region of CoAl-LDH with a spacing of 2.62 nm. The obtained nanohybrid exhibited a mesoporous texture with an expanded specific surface area of 62 m{sup 2} g{sup −1} and a superiormore » photocatalytic activity in the degradation of acid red with a reaction constant of 1.26 × 10{sup −2} min{sup −1} under visible-light radiation, which is more than 2 times those of his parents CoAl-LDH and CdS.« less

Reduced graphene oxide composites with water soluble copolymers having tailored lower critical solution temperatures and unique tube-like structure

NASA Astrophysics Data System (ADS)

Namvari, Mina; Biswas, Chandra S.; Galluzzi, Massimiliano; Wang, Qiao; Du, Bing; Stadler, Florian J.

2017-03-01

Nanohybrids of graphene with water soluble polymer were synthesized using ‘grafting from’ method. GO, prepared by modified Hummers’ method, was first reacted with sodium azide. Alkyne-terminated RAFT-CTA was synthesized by reaction of propargyl alcohol and S-1-dodecyl-S’-(α,α‘-dimethyl-α”-acetic acid) trithiocarbonate. RAFT-CTA was grafted onto the GO sheets by facile click-reaction and subsequently, N-isopropylacrylamide (NIPAM) and N-ethyleacrylamide (NEAM) were polymerized on graphene sheets via RAFT polymerization method. The respective copolymers with different ratios were also prepared. The nanohybrids were characterized by FTIR, XRD, TGA, Raman, SEM, and AFM. Both SEM and AFM clearly showed rod-like structures for rGO-PNEAM. XRD showed a small peak at 2θ = 19.21°, corresponding to d-spacing ≈ 4.6 Å. In addition, the nanohybrids showed a very broad temperature range for the LCST in water between ca. 30 and 70 °C.

Density-functional theory for fluid-solid and solid-solid phase transitions.

PubMed

Bharadwaj, Atul S; Singh, Yashwant

2017-03-01

We develop a theory to describe solid-solid phase transitions. The density functional formalism of classical statistical mechanics is used to find an exact expression for the difference in the grand thermodynamic potentials of the two coexisting phases. The expression involves both the symmetry conserving and the symmetry broken parts of the direct pair correlation function. The theory is used to calculate phase diagram of systems of soft spheres interacting via inverse power potentials u(r)=ε(σ/r)^{n}, where parameter n measures softness of the potential. We find that for 1/n<0.154 systems freeze into the face centered cubic (fcc) structure while for 1/n≥0.154 the body-centred-cubic (bcc) structure is preferred. The bcc structure transforms into the fcc structure upon increasing the density. The calculated phase diagram is in good agreement with the one found from molecular simulations.

Conversion of organic solids to hydrocarbons

DOEpatents

Greenbaum, Elias

1995-01-01

A method of converting organic solids to liquid and gaseous hydrocarbons includes impregnating an organic solid with photosensitizing ions and exposing the impregnated solid to light in a non-oxidizing atmosphere for a time sufficient to photocatalytically reduce the solid to at least one of a liquid and a gaseous hydrocarbon.

Toxin-induced conformational changes in a potassium channel revealed by solid-state NMR

NASA Astrophysics Data System (ADS)

Lange, Adam; Giller, Karin; Hornig, Sönke; Martin-Eauclaire, Marie-France; Pongs, Olaf; Becker, Stefan; Baldus, Marc

2006-04-01

The active site of potassium (K+) channels catalyses the transport of K+ ions across the plasma membrane-similar to the catalytic function of the active site of an enzyme-and is inhibited by toxins from scorpion venom. On the basis of the conserved structures of K+ pore regions and scorpion toxins, detailed structures for the K+ channel-scorpion toxin binding interface have been proposed. In these models and in previous solution-state nuclear magnetic resonance (NMR) studies using detergent-solubilized membrane proteins, scorpion toxins were docked to the extracellular entrance of the K+ channel pore assuming rigid, preformed binding sites. Using high-resolution solid-state NMR spectroscopy, here we show that high-affinity binding of the scorpion toxin kaliotoxin to a chimaeric K+ channel (KcsA-Kv1.3) is associated with significant structural rearrangements in both molecules. Our approach involves a combined analysis of chemical shifts and proton-proton distances and demonstrates that solid-state NMR is a sensitive method for analysing the structure of a membrane protein-inhibitor complex. We propose that structural flexibility of the K+ channel and the toxin represents an important determinant for the high specificity of toxin-K+ channel interactions.

Universality of (2+1)-dimensional restricted solid-on-solid models

NASA Astrophysics Data System (ADS)

Kelling, Jeffrey; Ódor, Géza; Gemming, Sibylle

2016-08-01

Extensive dynamical simulations of restricted solid-on-solid models in D =2 +1 dimensions have been done using parallel multisurface algorithms implemented on graphics cards. Numerical evidence is presented that these models exhibit Kardar-Parisi-Zhang surface growth scaling, irrespective of the step heights N . We show that by increasing N the corrections to scaling increase, thus smaller step-sized models describe better the asymptotic, long-wave-scaling behavior.

Effect of ammonium sulfate and urea on PCDD/F formation from active carbon and possible mechanism of inhibition.

PubMed

Yan, Mi; Qi, Zhifu; Yang, Jie; Li, Xiaodong; Ren, Jianli; Xu, Zhang

2014-11-01

The effect of ammonium sulfate ((NH4)2SO4) and urea (CO(NH2)2) on polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/F) formation from active carbon was investigated in this study. Both additives could significantly inhibit PCDD/F formation, and PCDD/F (TEQ) generation was reduced to 98.5% (98%) or 64.5% (77.2%) after 5% (NH4)2SO4 or CO(NH2)2 was added into model ash, respectively. The inhibition efficiency of PCDDs was higher than the value of PCDFs, however, the reduction of PCDD/F yield was mainly from PCDFs decreasing. In addition, the solid-phase products were reduced more than the gas-phase compounds by inhibitors. By the measurement of chlorine emission in the phase of ion (Cl[Cl(-)]) and molecule gas (Cl[Cl2]), it was observed that both Cl[Cl(-)] and Cl[Cl2] were reduced after inhibitors were added into ash. Cl[Cl2] was reduced to 51.0% by urea addition, which was supposed as one possible mechanism of PCDD/F inhibition. Copyright © 2014. Published by Elsevier B.V.

Study on the Pulsed Flashover Characteristics of Solid-Solid Interface in Electrical Devices Poured by Epoxy Resin

NASA Astrophysics Data System (ADS)

Li, Manping; Wu, Kai; Yang, Zhanping; Ding, Man; Liu, Xin; Cheng, Yonghong

2014-09-01

In electrical devices poured by epoxy resin, there are a lot of interfaces between epoxy resin and other solid dielectrics, i.e. solid-solid interfaces. Experiments were carried out to study the flashover characteristics of two typical solid-solid interfaces (epoxy-ceramic and epoxy-PMMA) under steep high-voltage impulse for different electrode systems (coaxial electrodes and finger electrodes) and different types of epoxy resin (neat epoxy resin, polyether modified epoxy resin and polyurethane modified epoxy resin). Results showed that, the flashover of solid-solid interface is similar to the breakdown of solid dielectric, and there are unrecoverable carbonated tracks after flashover. Under the same distance of electrodes, the electric stress of coaxial electrodes is lower than that of finger electrodes; and after the flashover, there are more severe breakdown and larger enhanced surface conductivity at interface for coaxial electrodes, as compared with the case of finger electrode. The dielectric properties are also discussed.

Behavioral inhibition and obsessive-compulsive disorder.

PubMed

Coles, Meredith E; Schofield, Casey A; Pietrefesa, Ashley S

2006-01-01

Behavioral inhibition is frequently cited as a vulnerability factor for development of anxiety. However, few studies have examined the unique relationship between behavioral inhibition and obsessive-compulsive disorder (OCD). Therefore, the current study addressed the relationship between behavioral inhibition and OCD in a number of ways. In a large unselected student sample, frequency of current OC symptoms was significantly correlated with retrospective self-reports of total levels of childhood behavioral inhibition. In addition, frequency of current OC symptoms was also significantly correlated with both social and nonsocial components of behavioral inhibition. Further, there was evidence for a unique relationship between behavioral inhibition and OC symptoms beyond the relationship of behavioral inhibition and social anxiety. In addition, results showed that reports of childhood levels of behavioral inhibition significantly predicted levels of OCD symptoms in adulthood. Finally, preliminary evidence suggested that behavioral inhibition may be more strongly associated with some types of OC symptoms than others, and that overprotective parenting may moderate the impact of behavioral inhibition on OC symptoms. The current findings suggest the utility of additional research examining the role of behavioral inhibition in the etiology of OCD.

Inhibition of microbial concrete corrosion by Acidithiobacillus thiooxidans with functionalised zeolite-A coating.

PubMed

Haile, Tesfaalem; Nakhla, George

2009-01-01

The inhibition of the corrosive action of Acidithiobacillus thiooxidans on concrete specimens coated by functionalised zeolite-A containing 14% zinc and 5% silver by weight was studied. Uncoated concrete specimens, epoxy-coated concrete specimens (EP), and functionalised zeolite-A coated concrete specimens with epoxy to zeolite weight ratios of 3:1 (Z1), 2:2 (Z2) and 1:3 (Z3) were studied. Specimens were characterised by x-ray powder diffraction and field emission scanning electron microscopy for the identification of corrosion products and morphological changes. Biomass growth at the conclusion of the 32-day experiments was 4, 179 and 193 mg volatile suspended solids g(-1) sulphur for the uncoated, EP and Z1 specimens, whereas that of Z2 and Z3 were negligible. In the uncoated, EP and Z1 specimens, sulphate production rates were 0.83, 9.1 and 8.8 mM SO(4)(2-) day(-1) and the specific growth rates, mu, were 0.14, 0.57 and 0.47 day(-1), respectively. The corresponding values for Z2 and Z3 were negligible due to their bacterial inhibition characteristics.

Energy and solid/hazardous waste

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

1981-12-01

This report addresses the past and potential future solid and hazardous waste impacts from energy development, and summarizes the major environmental, legislation applicable to solid and hazardous waste generation and disposal. A glossary of terms and acronyms used to describe and measure solid waste impacts of energy development is included. (PSB)

Conversion of organic solids to hydrocarbons

DOEpatents

Greenbaum, E.

1995-05-23

A method of converting organic solids to liquid and gaseous hydrocarbons includes impregnating an organic solid with photosensitizing ions and exposing the impregnated solid to light in a non-oxidizing atmosphere for a time sufficient to photocatalytically reduce the solid to at least one of a liquid and a gaseous hydrocarbon. 5 Figs.

SN-38 Acts as a Radiosensitizer for Colorectal Cancer by Inhibiting the Radiation-induced Up-regulation of HIF-1α.

PubMed

Okuno, Takayuki; Kawai, Kazushige; Hata, Keisuke; Murono, Koji; Emoto, Shigenobu; Kaneko, Manabu; Sasaki, Kazuhito; Nishikawa, Takeshi; Tanaka, Toshiaki; Nozawa, Hiroaki

2018-06-01

Hypoxia offers resistance to therapy in human solid tumors. The aim of the study was to investigate whether SN-38, the active metabolite of irinotecan, acts as a radiosensitizer through inhibition of hypoxia-inducible factor (HIF)-1α in the human colorectal cancer (CRC) cells. HT29 and SW480 cells were cultured with SN-38 (0-4 μM) immediately after irradiation (0-8 Gy). HIF-1α expression was assessed using flow-cytometry and western blot analysis. Cell proliferation was evaluated by the calcein assay. Apoptosis and cell cycle were determined by flow-cytometry. Radiation up-regulated HIF-1α, and SN-38 inhibited the radiation-induced HIF-1α. The combination of radiation and SN-38 inhibited cell proliferation more than radiation alone; treatment with SN-38 after radiation exposure did not increase the number of apoptotic cells, whereas, it enhanced the S and G 2 /M cell-cycle arrest and decreased the population of cells in G 1 Conclusion: SN-38 inhibits the radiation-induced up-regulation of HIF-1α and acts as a radiosensitizer by inducing cell-cycle arrest in CRC cells. Copyright© 2018, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

Flowmeter for gas-entrained solids flow

DOEpatents

Porges, Karl G.

1990-01-01

An apparatus and method for the measurement of solids feedrate in a gas-entrained solids flow conveyance system. The apparatus and method of the present invention include a vertical duct connecting a source of solids to the gas-entrained flow conveyance system, a control valve positioned in the vertical duct, and a capacitive densitometer positioned along the duct at a location a known distance below the control valved so that the solid feedrate, Q, of the gas entrained flow can be determined by Q=S.rho..phi.V.sub.S where S is the cross sectional area of the duct, .rho. is the density of the solid, .phi. is the solid volume fraction determined by the capacitive densitometer, and v.sub.S is the local solid velocity which can be inferred from the konown distance of the capacitive densitometer below the control valve.

Solid polymer electrolytes

DOEpatents

Abraham, Kuzhikalail M.; Alamgir, Mohamed; Choe, Hyoun S.

1995-01-01

This invention relates to Li ion (Li.sup.+) conductive solid polymer electrolytes composed of poly(vinyl sulfone) and lithium salts, and their use in all-solid-state rechargeable lithium ion batteries. The lithium salts comprise low lattice energy lithium salts such as LiN(CF.sub.3 SO.sub.2).sub.2, LiAsF.sub.6, and LiClO.sub.4.

Curved Solids Nets

ERIC Educational Resources Information Center

Cohen, Nitsa

2003-01-01

The transformation of a solid to its net is based on something quite different from simple perceptual impression. It is a mental operation performed by manipulating mental images. The aim of this study was to observe pre-service and in-service teachers' ability to visualize the transformation of a curved solid to its net and vice versa, and to try…

Solid Surface Combustion Experiment

NASA Image and Video Library

1994-09-12

STS064-10-011 (12 Sept. 1994) --- The Solid Surface Combustion Experiment (SSCE), designed to supply information on flame spread over solid fuel surfaces in the reduced-gravity environment of space, is pictured during flight day four operations. The middeck experiment measured the rate of spreading, the solid-phase temperature, and the gas-phase temperature of flames spreading over rectangular fuel beds. STS-64 marked the seventh trip into space for the Lewis Research Center experiment. Photo credit: NASA or National Aeronautics and Space Administration

Valve for controlling solids flow

DOEpatents

Staiger, M. Daniel

1985-01-01

A valve for controlling the flow of solids comprises a vessel having an overflow point, an inlet line for discharging solids into the vessel positioned within the vessel such that the inlet line's discharge point is lower than the vessel's overflow point, and apparatus for introducing a fluidizing fluid into the vessel. The fluidizing fluid fluidizes the solids within the vessel so that they overflow at the vessel's overflow point. For the removal of nuclear waste product the vessel may be placed within a sealed container having a bottom connected transport line for transporting the solids to storage or other sites. The rate of solids flow is controlled by the flow rate of the fluidizing fluid and by V-notch weirs of different sizes spaced about the top of the vessel.

Valve for controlling solids flow

DOEpatents

Staiger, M.D.

1982-09-29

A valve for controlling the flow of solids comprises a vessel having an overflow point, an inlet line for discharging solids into the vessel positioned within the vessel such that the inlet line's discharge point is lower than the vessel's overflow point, and means for introducing a fluidizing fluid into the vessel. The fluidizing fluid fluidizes the solids within the vessel so that they overflow at the vessel's overflow point. For the removal of nuclear waste product the vessel may be placed within a sealed container having a bottom connected transport line for transporting the solids to storage or other sites. The rate of solids flow is controlled by the flow rate of the fluidizing fluid and by V-notch weirs of different sizes spaced about the top of the vessel.

Human cathelicidin peptide LL37 inhibits both attachment capability and biofilm formation of Staphylococcus epidermidis.

PubMed

Hell, E; Giske, C G; Nelson, A; Römling, U; Marchini, G

2010-02-01

The aim of this work was to investigate the possible effect of human cathelicidin antimicrobial peptide LL37 on biofilm formation of Staphylococcus epidermidis, a major causative agent of indwelling device-related infections. We performed initial attachment assay and biofilm formation solid surface assay in microtitre plates, as well as growth experiment in liquid medium using laboratory strain Staph. epidermidis ATCC35984. We found that already a low concentration of the peptide LL37 (1 mg l(-1)) significantly decreased both the attachment of bacteria to the surface and also the biofilm mass. No growth inhibition was observed even at 16 mg l(-1) concentration of LL37, indicating a direct effect of the peptide on biofilm production. As biofilm protects bacteria during infections in humans and allows their survival in a hostile environment, inhibition of biofilm formation by LL37 may have a key role to prevent bacterial colonization on indwelling devices. Our findings suggest that this host defence factor can be a potential candidate in prevention and treatment strategies of Staph. epidermidis infections in humans.

Molecular-level elucidation of saccharin-assisted rapid dissolution and high supersaturation level of drug from Eudragit® E solid dispersion.

PubMed

Ueda, Keisuke; Kanaya, Harunobu; Higashi, Kenjirou; Yamamoto, Keiji; Moribe, Kunikazu

2018-03-01

In this work, the effect of saccharin (SAC) addition on the dissolution and supersaturation level of phenytoin (PHT)/Eudragit® E (EUD-E) solid dispersion (SD) at neutral pH was examined. The PHT/EUD-E SD showed a much slower dissolution of PHT compared to the PHT/EUD-E/SAC SD. EUD-E formed a gel layer after the dispersion of the PHT/EUD-E SD into an aqueous medium, resulting in a slow dissolution of PHT. Pre-dissolving SAC in the aqueous medium significantly improved the dissolution of the PHT/EUD-E SD. Solid-state 13 C NMR measurements showed an ionic interaction between the tertiary amino group of EUD-E and the amide group of SAC in the EUD-E gel layer. Consequently, the ionized EUD-E could easily dissolve from the gel layer, promoting PHT dissolution. Solution-state 1 H NMR measurements revealed the presence of ionic interactions between SAC and the amino group of EUD-E in the PHT/EUD-E/SAC solution. In contrast, interactions between PHT and the hydrophobic group of EUD-E strongly inhibited the crystallization of the former from its supersaturated solution. The PHT supersaturated solution was formed from the PHT/EUD-E/SAC SD by the fast dissolution of PHT and the strong crystallization inhibition effect of EUD-E after aqueous dissolution. Copyright © 2018 Elsevier B.V. All rights reserved.

Diffusive and martensitic nucleation kinetics in solid-solid transitions of colloidal crystals

NASA Astrophysics Data System (ADS)

Peng, Yi; Li, Wei; Wang, Feng; Still, Tim; Yodh, Arjun G.; Han, Yilong

2017-05-01

Solid-solid transitions between crystals follow diffusive nucleation, or various diffusionless transitions, but these kinetics are difficult to predict and observe. Here we observed the rich kinetics of transitions from square lattices to triangular lattices in tunable colloidal thin films with single-particle dynamics by video microscopy. Applying a small pressure gradient in defect-free regions or near dislocations markedly transform the diffusive nucleation with an intermediate-stage liquid into a martensitic generation and oscillation of dislocation pairs followed by a diffusive nucleus growth. This transformation is neither purely diffusive nor purely martensitic as conventionally assumed but a combination thereof, and thus presents new challenges to both theory and the empirical criterion of martensitic transformations. We studied how pressure, density, grain boundary, triple junction and interface coherency affect the nucleus growth, shape and kinetic pathways. These novel microscopic kinetics cast new light on control solid-solid transitions and microstructural evolutions in polycrystals.

Comparison of a solid SMEDDS and solid dispersion for enhanced stability and bioavailability of clopidogrel napadisilate.

PubMed

Kim, Dong Wuk; Kwon, Min Seok; Yousaf, Abid Mehmood; Balakrishnan, Prabagar; Park, Jong Hyuck; Kim, Dong Shik; Lee, Beom-Jin; Park, Young Joon; Yong, Chul Soon; Kim, Jong Oh; Choi, Han-Gon

2014-12-19

The intention of this study was to compare the physicochemical properties, stability and bioavailability of a clopidogrel napadisilate (CN)-loaded solid dispersion (SD) and solid self-microemulsifying drug delivery system (solid SMEDDS). SD was prepared by a surface attached method using different ratios of Cremophor RH60 (surfactant) and HPMC (polymer), optimized based on their drug solubility. Liquid SMEDDS was composed of oil (peceol), a surfactant (Cremophor RH60) and a co-surfactant (Transcutol HP). A pseudo-ternary phase diagram was constructed to identify the emulsifying domain, and the optimized liquid SMEDDS was spray dried with an inert solid carrier (silicon dioxide), producing the solid SMEDDS. The physicochemical properties, solubility, dissolution, stability and pharmacokinetics were assessed and compared to clopidogrel napadisilate (CN) and bisulfate (CB) powders. In solid SMEDDS, liquid SMEDDS was absorbed or coated inside the pores of silicon dioxide. In SD, hydrophilic polymer and surfactants were adhered onto drug surface. The drug was in crystalline and molecularly dispersed form in SD and solid SMEDDS, respectively. Solid SMEDDS and SD greatly increased the solubility of CN but gave lower drug solubility compared to CB powder. These preparations significantly improved the dissolution of CN, but the latter more increased than the former. Stability under accelerated condition showed that they were more stable compared to CB powder, and SD was more stable than solid SMEDDS. They significantly increased the oral bioavailability of CN powder. Furthermore, SD showed significantly improved oral bioavailability compared to solid SMEDDS and CB powder. Thus, SD with excellent stability and bioavailability is recommended as an alternative for the clopidogrel-based oral formulation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Enhanced solubility and intestinal absorption of candesartan cilexetil solid dispersions using everted rat intestinal sacs.

PubMed

Gurunath, S; Nanjwade, Baswaraj K; Patila, P A

2014-07-01

Candesartan cilexetil (CAN) is a poor aqueous soluble compound and a P-glycoprotein (P-gp) efflux pump substrate. These key factors are responsible for its incomplete intestinal absorption. In this study, we investigated to enhance the absorption of CAN by improving its solubility and inhibiting intestinal P-gp activity. A phase solubility method was used to evaluate the aqueous solubility of CAN in PVP K30 (0.2-2%). Gibbs free energy [Formula: see text] values were all negative. Solubility was enhanced by the freeze drying technique. The in vitro dissolution was evaluated using the USP paddle method. The interaction between drug and carrier was evaluated by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Differential scanning calorimetry (DSC) studies. Naringin was selected as P-gp inhibitor. Absorption studies were performed using the everted gut sac model from rat jejunum. The drug analysis was performed by HPLC. FTIR spectra revealed no interaction between drug and PVP K30. From XRD and DSC data, CAN was in the amorphous form, which explains the cumulative release of drug from its prepared systems. We noticed an enhancement of CAN absorption by improving its solubility and inhibiting the P-gp activity. The significant results (p < 0.05) were obtained for freeze dried solid dispersions in the presence of P-gp inhibitor than without naringin (15 mg/kg) with an absorption enhancement of 8-fold. Naringin, a natural flavonoid, has no undesirable side effects. Therefore, it could be employed as an excipient in the form of solid dispersions to increase CAN intestinal absorption and its oral bioavailability.

Enhanced solubility and intestinal absorption of candesartan cilexetil solid dispersions using everted rat intestinal sacs

PubMed Central

Gurunath, S.; Nanjwade, Baswaraj K.; Patila, P.A.

2013-01-01

Objective Candesartan cilexetil (CAN) is a poor aqueous soluble compound and a P-glycoprotein (P-gp) efflux pump substrate. These key factors are responsible for its incomplete intestinal absorption. Methods In this study, we investigated to enhance the absorption of CAN by improving its solubility and inhibiting intestinal P-gp activity. A phase solubility method was used to evaluate the aqueous solubility of CAN in PVP K30 (0.2–2%). Gibbs free energy (ΔGtro) values were all negative. Solubility was enhanced by the freeze drying technique. The in vitro dissolution was evaluated using the USP paddle method. The interaction between drug and carrier was evaluated by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Differential scanning calorimetry (DSC) studies. Naringin was selected as P-gp inhibitor. Absorption studies were performed using the everted gut sac model from rat jejunum. The drug analysis was performed by HPLC. Results FTIR spectra revealed no interaction between drug and PVP K30. From XRD and DSC data, CAN was in the amorphous form, which explains the cumulative release of drug from its prepared systems. We noticed an enhancement of CAN absorption by improving its solubility and inhibiting the P-gp activity. The significant results (p < 0.05) were obtained for freeze dried solid dispersions in the presence of P-gp inhibitor than without naringin (15 mg/kg) with an absorption enhancement of 8-fold. Conclusion Naringin, a natural flavonoid, has no undesirable side effects. Therefore, it could be employed as an excipient in the form of solid dispersions to increase CAN intestinal absorption and its oral bioavailability. PMID:25067902

The solid waste dilemma

USGS Publications Warehouse

Amey, E.B.; Russell, J.A.; Hurdelbrink, R.J.

1996-01-01

In 1976, the U.S. Congress enacted the Resource Conservation and Recovery Act (RCRA) to further address the problem of increasing industrial and municipal waste. The main objectives of RCRA were to responsibly manage hazardous and solid waste and to procure materials made from recovered wastes. To fulfill these objectives, four main programs of waste management were developed. These programs were defined under Subtitle C, the Hazardous Waste Program; Subtitle D, the Solid Waste Program; Subtitle I, the Underground Storage Tank Program; and Subtitle J, the Medical Waste Program. Subtitle D illustrates the solid waste dilemma occurring in the United States. Under this program, states are encouraged to develop and implement their own waste management plans. These plans include the promotion of recycling solid wastes and the closing and upgrading of all environmentally unsound dumps. ?? 1996 International Association for Mathematical Geology.

Thermal treatment and leaching of biochar alleviates plant growth inhibition from mobile organic compounds

PubMed Central

Sackett, Tara E.; Thomas, Sean C.

2016-01-01

Recent meta-analyses of plant responses to biochar boast positive average effects of between 10 and 40%. Plant responses, however, vary greatly across systems, and null or negative biochar effects are increasingly reported. The mechanisms responsible for such responses remain unclear. In a glasshouse experiment we tested the effects of three forestry residue wood biochars, applied at five dosages (0, 5, 10, 20, and 50 t/ha) to a temperate forest drystic cambisol as direct surface applications and as complete soil mixes on the herbaceous pioneers Lolium multiflorum and Trifolium repens. Null and negative effects of biochar on growth were found in most cases. One potential cause for null and negative plant responses to biochar is plant exposure to mobile compounds produced during pyrolysis that leach or evolve following additions of biochars to soil. In a second glasshouse experiment we examined the effects of simple leaching and heating techniques to ameliorate potentially phytotoxic effects of volatile and leachable compounds released from biochar. We used Solid Phase Microextraction (SPME)–gas chromatography–mass spectrometry (GC-MS) to qualitatively describe organic compounds in both biochar (through headspace extraction), and in the water leachates (through direct injection). Convection heating and water leaching of biochar prior to application alleviated growth inhibition. Additionally, growth was inhibited when filtrate from water-leached biochar was applied following germination. SPME-GC-MS detected primarily short-chained carboxylic acids and phenolics in both the leachates and solid chars, with relatively high concentrations of several known phytotoxic compounds including acetic acid, butyric acid, 2,4-di-tert-butylphenol and benzoic acid. We speculate that variable plant responses to phytotoxic organic compounds leached from biochars may largely explain negative plant growth responses and also account for strongly species-specific patterns of plant

Solid polymer electrolytes

DOEpatents

Abraham, K.M.; Alamgir, M.; Choe, H.S.

1995-12-12

This invention relates to Li ion (Li{sup +}) conductive solid polymer electrolytes composed of poly(vinyl sulfone) and lithium salts, and their use in all-solid-state rechargeable lithium ion batteries. The lithium salts comprise low lattice energy lithium salts such as LiN(CF{sub 3}SO{sub 2}){sub 2}, LiAsF{sub 6}, and LiClO{sub 4}. 2 figs.

Synthesis of azines in solid state: reactivity of solid hydrazine with aldehydes and ketones.

PubMed

Lee, Byeongno; Lee, Kyu Hyung; Cho, Jaeheung; Nam, Wonwoo; Hur, Nam Hwi

2011-12-16

Highly conjugated azines were prepared by solid state grinding of solid hydrazine and carbonyl compounds such as aldehydes and ketones, using a mortar and a pestle. Complete conversion to the azine product is generally achieved at room temperature within 24 h, without using solvents or additives. The solid-state reactions afford azines as the sole products with greater than 97% yield, producing only water and carbon dioxide as waste.

Fluidized-Solid-Fuel Injection Process

NASA Technical Reports Server (NTRS)

Taylor, William

1992-01-01

Report proposes development of rocket engines burning small grains of solid fuel entrained in gas streams. Main technical discussion in report divided into three parts: established fluidization technology; variety of rockets and rocket engines used by nations around the world; and rocket-engine equation. Discusses significance of specific impulse and ratio between initial and final masses of rocket. Concludes by stating three important reasons to proceed with new development: proposed engines safer; fluidized-solid-fuel injection process increases variety of solid-fuel formulations used; and development of fluidized-solid-fuel injection process provides base of engineering knowledge.

p-Adic solid-on-solid model on a Cayley tree

NASA Astrophysics Data System (ADS)