SU-G-TeP3-15: Radiation Dose Enhancement by Anatase TiO2NPs

Energy Technology Data Exchange (ETDEWEB)

Youkhana, E; Geso, M; Feltis, B [RMIT University, Melbourne, VIC (Australia)

2016-06-15

Purpose: This work investigates radiation dose enhancement caused by TiO2 nanoparticles covering entire X-ray energy ranges used in radiation therapy. Methods: Anatase TiO2NPs crystal were synthesised and modified as hydrophilic and hydrophobic to disperse in culture-medium and halocarbons (PRESAGE chemical composition) respectively. TiO2NPs were characterised using TEM, XPS, XRD, TGA and FTIR. Various Concentrations have been utilised for determination of radiation-dose enhancement. This investigation is carried out in two ways; one using PRESAGE dosimeter/phantom and the other is radiobiological and based on in vitro study using two types of cell lines, Human Keratinocyte (HaCaT) and prostate cancer cell lines. The x-ray used are both kilovoltage and megavoltage separately. The prepared PRESAGE dosimeters were scanned using optical CT scanner. Clonogenic and MTS assays were employed for cell cytotoxicity and viability measurements for determination of the levels of dose enhancement. Results: Significant about (50%, 45%) dose enhancement by TiO2-NPs for kV x-rays is measured in both ways (Presage and Cells study). Slightly more is detected with the cells. However, the dose enhancement with megavoltage beams was insignificant using Presage and under same conditions the cells survival curves indicates around 20% which is relatively high. This difference can only be attributed to some biochemical effects. Such as generation of reactive oxygen species (ROS), this can affect the cells while it can’t be detected by Presage. Elevation of hydroxyl radicals (•OH) of many orders is observed with the inclusion of TiO2-NPs in cells-medium. Conclusion: Dose enhancement inflicted by TiO2-NPs is proven to be significant with megavoltage beams and minimal with kV. The high dose enhancements obtained can be attributed to higher levels of ROS generated. Since MV beams are most commonly used, this research proves potential value for more efficient beam delivery. This has

Efficient surface enhanced Raman scattering on confeito-like gold nanoparticle-adsorbed self-assembled monolayers.

Science.gov (United States)

Chang, Chia-Chi; Imae, Toyoko; Chen, Liang-Yih; Ujihara, Masaki

2015-12-28

Confeito-like gold nanoparticles (AuNPs; average diameter = 80 nm) exhibiting a plasmon absorption band at 590 nm were adsorbed through immersion-adsorption on two self-assembled monolayers (SAMs) of 3-aminopropyltriethoxysilane (APTES-SAM) and polystyrene spheres coated with amine-terminated poly(amido amine) dendrimers (DEN/PS-SAM). The surface enhanced Raman scattering (SERS) effect on the SAM substrates was examined using the molecules of a probe dye, rhodamine 6G (R6G). The Raman scattering was strongly intensified on both substrates, but the enhancement factor (>10,000) of the AuNP/DEN/PS-SAM hierarchy substrate was 5-10 times higher than that of the AuNP/APTES-SAM substrate. This strong enhancement is attributed to the large surface area of the substrate and the presence of hot spots. Furthermore, analyzing the R6G concentration dependence of SERS suggested that the enhancement mechanism effectively excited the R6G molecules in the first layer on the hot spots and invoked the strong SERS effect. These results indicate that the SERS activity of confeito-like AuNPs on SAM substrates has high potential in molecular electronic devices and ultrasensitive analyses.

Characteristics of Polysilicon Wire Glucose Sensors with a Surface Modified by Silica Nanoparticles/γ-APTES Nanocomposite

Directory of Open Access Journals (Sweden)

Jheng-Jia Jhuang

2011-03-01

Full Text Available This report investigates the sensing characteristics of polysilicon wire (PSW glucose biosensors, including thickness characteristics and line-width effects on detection limits, linear range and interference immunity with membranes coated by micropipette/spin-coating and focus-ion-beam (FIB processed capillary atomic-force-microscopy (C-AFM tip scan/coating methods. The PSW surface was modified with a mixture of 3-aminopropyl-triethoxysilane (γ-APTES and polydimethylsiloxane (PDMS-treated hydrophobic fumed silica nanoparticles (NPs. We found that the thickness of the γ-APTES+NPs nonocomposite could be controlled well at about 22 nm with small relative standard deviation (RSD with repeated C-AFM tip scan/coatings. The detection limit increased and linear range decreased with the line width of the PSW through the tip-coating process. Interestingly, the interference immunity ability improves as the line width increases. For a 500 nm-wide PSW, the percentage changes of the channel current density changes (ΔJ caused by acetaminophen (AP can be kept below 3.5% at an ultra-high AP-to-glucose concentration ratio of 600:1. Simulation results showed that the line width dependence of interference immunity was strongly correlated with the channel electrical field of the PSW biosensor.

Gum tragacanth stabilized green gold nanoparticles as cargos for Naringin loading: A morphological investigation through AFM.

Science.gov (United States)

Rao, Komal; Imran, Muhammad; Jabri, Tooba; Ali, Imdad; Perveen, Samina; Shafiullah; Ahmed, Shakil; Shah, Muhammad Raza

2017-10-15

Gold nanoparticles (AuNPs) have attracted greater scientific interests for the construction of drugs loading cargos due to their biocompatibility, safety and facile surface modifications. This study deals with the fabrication of gum tragacanth (GT) green AuNPs as carrier for Naringin, a less water soluble therapeutic molecule. The optimized AuNPs were characterized through UV-vis spectroscopy, FT-IR and atomic force microscope (AFM). Naringin loaded nanoparticles were investigated for their bactericidal potentials using Tetrazolium Microplate assay. Morphological studies conducted via AFM revealed spherical shape for AuNPs with nano-range size and stabilized by GT multi-functional groups. The AuNPs acted as carrier for increased amount of Naringin. Upon loading in AuNPs, Naringin An increased in the bactericidal potentials of Naringin was observed after loading on AuNPs against various tested bacterial strains. This was further authenticated by the surface morphological analysis, showing enhanced membrane destabilizing effects of loaded Naringin. The results suggest that GT stabilized green AuNPs can act as effective delivery vehicles for enhancing bactericidal potentials of Naringin. Copyright © 2017 Elsevier Ltd. All rights reserved.

Automated prototyping tool-kit (APT)

OpenAIRE

Nada, Nader; Shing, M.; Berzins, V.; Luqi

2002-01-01

Automated prototyping tool-kit (APT) is an integrated set of software tools that generate source programs directly from real-time requirements. The APT system uses a fifth-generation prototyping language to model the communication structure, timing constraints, 1/0 control, and data buffering that comprise the requirements for an embedded software system. The language supports the specification of hard real-time systems with reusable components from domain specific component libraries. APT ha...

Fabrication of uniformly dispersed Ag nanoparticles loaded TiO{sub 2} nanotube arrays for enhancing photoelectrochemical and photocatalytic performances under visible light irradiation

Energy Technology Data Exchange (ETDEWEB)

Yi, Junhui; Zhang, Shengsen; Wang, Hongjuan; Yu, Hao; Peng, Feng, E-mail: cefpeng@scut.edu.cn

2014-12-15

Graphical abstract: Uniformly dispersed Ag nanoparticles (NPs) were successfully loaded on both the outer and inner surface of the TiO{sub 2} nanotube arrays (NTs) through a simple polyol method, which exhibited the enhanced photoelectrochemical and photocatalytic performances under visible-light irradiation due to the more effective separation of photo-generated electron–hole pairs and faster interfacial charge transfer. - Highlights: • Highly dispersed Ag nanoparticles (NPs) are successfully prepared by polyol method. • Ag NPs are uniformly loaded on the surface of the TiO{sub 2} nanotube arrays (NTs). • Ag/TiO{sub 2}-NTs exhibit the enhanced photocatalytic activity under visible-light. • The enhanced photocurrent is explained by electrochemical impedance spectroscopy. - Abstract: Uniformly dispersed Ag nanoparticles (NPs) were successfully loaded on both the outer and inner surface of the TiO{sub 2} nanotube arrays (NTs) through a simple polyol method. The as-prepared Ag/TiO{sub 2}-NTs were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and UV–vis diffusion reflectance spectroscopy. Photoelectrochemical behaviors were investigated via photocurrent response and electrochemical impedance spectroscopy (EIS). Photocatalytic activity of Ag/TiO{sub 2}-NTs was evaluated by degradation of acid orange II under visible light irradiation. The results showed that photocatalytic efficiency of Ag/TiO{sub 2}-NTs is more than 5 times higher than that of pure TiO{sub 2} NTs. Comparing with the electrochemical deposition method, the photocatalytic activity of Ag/TiO{sub 2}-NTs prepared by polyol method has been obviously increased.

Waste management plan for the APT

International Nuclear Information System (INIS)

England, J.L.

1997-01-01

This revision of the APT Waste Management Plan details the waste management requirements and issues specific to the APT plant for design considerations, construction, and operation. The APT Waste Management Plan is by its nature a living document and will be reviewed at least annually and revised as required

Application of integrated GIS and multimedia modeling on NPS pollution evaluation.

Science.gov (United States)

Lin, C E; Kao, C M; Lai, Y C; Shan, W L; Wu, C Y

2009-11-01

In Taiwan, nonpoint source (NPS) pollution is one of the major causes of the impairment of surface waters. I-Liao Creek, located in southern Taiwan, flows approximately 90 km and drains toward the Kaoping River. Field investigation results indicate that NPS pollution from agricultural activities is one of the main water pollution sources in the I-Liao Creek Basin. Assessing the potential of NPS pollution to assist in the planning of best management practice (BMP) is significant for improving pollution prevention and control in the I-Liao Creek Basin. In this study, land use identification in the I-Liao Creek Basin was performed by properly integrating the skills of geographic information system (GIS) and global positioning system (GPS). In this analysis, 35 types of land use patterns in the watershed area of the basin are classified with the aid of Erdas Imagine process system and ArcView GIS system. Results indicate that betel palm farms, orchard farms, and tea gardens dominate the farmland areas in the basin, and are scattered around on both sides of the river corridor. An integrated watershed management model (IWMM) was applied for simulating the water quality and evaluating NPS pollutant loads to the I-Liao Creek. The model was calibrated and verified with collected water quality and soil data, and was used to investigate potential NPS pollution management plans. Simulated results indicate that NPS pollution has significant contributions to the nutrient loads to the I-Liao Creek during the wet season. Results also reveal that NPS pollution plays an important role in the deterioration of downstream water quality and caused significant increase in nutrient loads into the basin's water bodies. Simulated results show that source control, land use management, and grassy buffer strip are applicable and feasible BMPs for NPS nutrient loads reduction. GIS system is an important method for land use identification and waste load estimation in the basin. Linking the

Lycopene loaded whey protein isolate nanoparticles: An innovative endeavor for enhanced bioavailability of lycopene and anti-cancer activity.

Science.gov (United States)

Jain, Ashay; Sharma, Gajanand; Ghoshal, Gargi; Kesharwani, Prashant; Singh, Bhupinder; Shivhare, U S; Katare, O P

2018-04-28

The work entails a novel strategy of formulating the lycopene loaded whey protein isolate nanoparticles (LYC-WPI-NPs) solely using the rational blend of biomacromolecule without using equipment-intensive techniques. The LYC-WPI-NPs were fabricated as a substantial drug delivery platform, with maximum entrapment, spatial and controlled release manners, exceptional plasma concentration, and perspective for discrepancy delivery of therapeutics. Prepared nano-formulations were measured in ultra-fine size (100-350 nm) with sphere-shaped. The percent lycopene entrapment of prepared LYC-WPI-NPs was estimated in the range to 50 and 65%. In vitro percent cumulative release study demonstrated deaden and extended release i.e. approximately 75% following 16 th h. The in vitro percent cell survival (cytotoxicity study) of prepared nanoparticles was evaluated against MCF-7 breast cancer cells by MTT based colorimetric assay. Sub-cellular localization of lycopene when delivered by LYC-WPI-NPs was assessed by HPLC (high performance liquid chromatography). The WPI-NPs enhance the oral bioavailability of lycopene by controlling its release from nano-formulation and facilitating its absorption through lymphatic pathways. Prophylactic anticancer efficacy of LYC-WPI-NPs was evaluated thereafter on experimentally induced breast cancer animal model. Conclusively, it may quite reasonable that lycopene loaded protein nanoparticles are competent to improve the biopharmaceutical attributes of lycopene and demonstrated prophylactic anticancer activity, decrease tumor proliferation and increase the survival rate of treated animals, thus signifying their feasible usefulness in cancer therapeutic and intervention. Copyright © 2018. Published by Elsevier B.V.

Synthesis and their enhanced photoelectrochemical performance of ZnO nanoparticle-loaded CuO dandelion heterostructures under solar light

Energy Technology Data Exchange (ETDEWEB)

Dong, Guanying; Du, Bin; Liu, Lei; Zhang, Weiwei; Liang, Yujie; Shi, Honglong; Wang, Wenzhong, E-mail: wzhwangmuc@163.com

2017-03-31

Highlights: • ZnO/CuO nanoparticle/dandelion heterostructures were fabricated for the first time. • ZnO/CuO nanoparticle/dandelion heterostructures show enhanced PEC activity. • ZnO nanoparticle loading contents have significant effect on PEC water splitting. • Interaction, charge transfer and enhanced mechanism of photocatalyst were proposed. • p-n junction drives the photoexcited charges efficient separation. - Abstract: Here we report an easy and large-scale synthesis of three-dimensional (3D) ZnO nanoparticle-loaded CuO dandelion (denoted as n-ZnO/p-CuO nanoparticle/dandelion) heterostructures and their photoelectrochemical (PEC) water splitting under simulated solar light illumination. CuO dandelions were fabricated by a facile and cost-effective chemical strategy, in which the ribbon-like CuO nanoplates were first formed and then assembled into dandelion-like architectures. ZnO nanoparticle-loaded CuO dandelion heterostructures were fabricated by calcining Zn(Ac){sub 2}-loaded CuO dandelions. High resolution transmission electron microscope (HRTEM) studies demonstrate that intimate p-n junction is built between p-CuO and n-ZnO interface. The n-ZnO/p-CuO nanoparticle/dandelion photoelectrodes exhibit significant improvement in PEC water splitting to CuO dandelion photoelectrodes. The correlation between photocurrents and different loading contents of ZnO nanoparticles (NPs) is studied in which the n-ZnO/p-CuO nanoparticle/dandelion heterostructures with loading 4.6 wt% ZnO NPs show higher photocathodic current. The efficient separation of the photogenerated electrons and holes driven by the intimate p-n junction between p-type CuO and n-type ZnO interface is mainly contributed to the enhanced photoanode current. The achieved results in the present study offer a very useful strategy for designing p-n junction photoelectrodes for efficiency and low-cost PEC cells for clean solar hydrogen production.

APT: Aperture Photometry Tool

Science.gov (United States)

Laher, Russ

2012-08-01

Aperture Photometry Tool (APT) is software for astronomers and students interested in manually exploring the photometric qualities of astronomical images. It has a graphical user interface (GUI) which allows the image data associated with aperture photometry calculations for point and extended sources to be visualized and, therefore, more effectively analyzed. Mouse-clicking on a source in the displayed image draws a circular or elliptical aperture and sky annulus around the source and computes the source intensity and its uncertainty, along with several commonly used measures of the local sky background and its variability. The results are displayed and can be optionally saved to an aperture-photometry-table file and plotted on graphs in various ways using functions available in the software. APT is geared toward processing sources in a small number of images and is not suitable for bulk processing a large number of images, unlike other aperture photometry packages (e.g., SExtractor). However, APT does have a convenient source-list tool that enables calculations for a large number of detections in a given image. The source-list tool can be run either in automatic mode to generate an aperture photometry table quickly or in manual mode to permit inspection and adjustment of the calculation for each individual detection. APT displays a variety of useful graphs, including image histogram, and aperture slices, source scatter plot, sky scatter plot, sky histogram, radial profile, curve of growth, and aperture-photometry-table scatter plots and histograms. APT has functions for customizing calculations, including outlier rejection, pixel “picking” and “zapping,” and a selection of source and sky models. The radial-profile-interpolation source model, accessed via the radial-profile-plot panel, allows recovery of source intensity from pixels with missing data and can be especially beneficial in crowded fields.

Evaluation of self-assembled HCPT-loaded PEG-b-PLA nanoparticles by comparing with HCPT-loaded PLA nanoparticles.

Science.gov (United States)

Yang, Xiangrui; Wu, Shichao; Wang, Yange; Li, Yang; Chang, Di; Luo, Yin; Ye, Shefang; Hou, Zhenqing

2014-12-01

We present a dialysis technique to prepare the 10-hydroxycamptothecin (HCPT)-loaded nanoparticles (NPs) using methoxypolyethylene glycol-poly(D,L-lactide) (PEG-b-PLA) and PLA, respectively. Both HCPT-loaded PEG-b-PLA NPs and HCPT-loaded PLA NPs were characterized by differential scanning calorimetry (DSC), dynamic light scattering (DLS), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). The results showed that the HCPT-loaded PEG-b-PLA NPs and HCPT-loaded PLA NPs presented a hydrodynamic particle size of 120.1 and 226.8 nm, with a polydispersity index of 0.057 and 0.207, a zeta potential of -31.2 and -45.7 mV, drug encapsulation efficiency of 44.52% and 44.94%, and drug-loaded content of 7.42% and 7.49%, respectively. The HCPT-loaded PEG-b-PLA NPs presented faster drug release rate compared to the HCPT-loaded PLA NPs. The HCPT-loaded PEG-b-PLA NPs presented higher cytotoxicity than the HCPT-loaded PLA NPs. These results suggested that the HCPT-loaded PEG-b-PLA NPs presented better characteristics for drug delivery compared to HCPT-loaded PLA NPs.

Enhanced delivery of biodegradable mPEG-PLGA-PLL ...

Indian Academy of Sciences (India)

... effectively down-regulate the mRNA and protein expression of PDGF‐BB thanNPs plus US (P=0.014 and P=0.007, respectively). Histology showed no evident tissue damage after UTMDmediatedNPs loading siRNA transfection. UTMD could be used safely to enhance the delivery of mPEG-PLGAPLLNPs loading siRNA ...

Enhancement of TiO2 NPs Activity by Fe3O4 Nano-Seeds for Removal of Organic Pollutants in Water

Directory of Open Access Journals (Sweden)

Silvia Villa

2016-09-01

Full Text Available The enhancement of the photocatalytic activity of TiO2 nanoparticles (NPs, synthesized in the presence of a very small amount of magnetite (Fe3O4 nanoparticles, is here presented and discussed. From X-ray diffraction (XRD and differential scanning calorimetry (DSC analyses, the crystallinity of TiO2 nanoparticles (NPs seems to be affected by Fe3O4, acting as nano-seeds to improve the tetragonal TiO2 anatase structure with respect to the amorphous one. Photocatalytic activity data, i.e., the degradation of methylene blue and the Ofloxacin fluoroquinolone emerging pollutant, give evidence that the increased crystalline structure of the NPs, even if correlated to a reduced surface to mass ratio (with respect to commercial TiO2 NPs, enhances the performance of this type of catalyst. The achievement of a relatively well-defined crystal structure at low temperatures (Tmax = 150 °C, preventing the sintering of the TiO2 NPs and, thus, preserving the high density of active sites, seems to be the keystone to understand the obtained results.

AgNPs-3D nanostructure enhanced electrochemiluminescence of CdSe quantum dot coupled with strand displacement amplification for sensitive biosensing of DNA

International Nuclear Information System (INIS)

Jiao, Meng; Jie, Guifen; Tan, Lu; Niu, Shuyan

2017-01-01

A novel strategy using Ag nanoparticles-3D (AgNPs-3D) nanostructure enhanced electrochemiluminescence (ECL) of CdSe quantum dots (QDs) coupled with strand displacement amplification (SDA) for sensitive biosensing of DNA was successfully designed. The prepared CdSe QDs with intense ECL were assembled on the poly (diallyldimethylammonium chloride) (PDDA) graphene oxide (GO) nanocomposites modified electrode, then gold nanoparticles (NPs) as the quenching probe was conjugated to the QDs, ECL signal was efficiently quenched. The target DNA induced cycling SDA and generated a large number of DNA s1. The released DNA s1 could open the hairpin DNA with quenching probe. So the presence of low levels of target DNA can potentially result in a significant enhancement of ECL signal. Furthermore, large number of AgNPs were then in situ reduced in the 3D DNA skeleton on the electrode, which dramaticlly enhanced ECL signal of QDs owing to the excellent electrical conductivity, and the much amplified ECL signal change has a quantitative relation with the target DNA. So by combining the AgNPs-3D nanostructure and cycling SDA to achieve greatly amplified detection of DNA, the promising ECL strategy could provide a highly sensitive platform for various biomolecules and has a good prospect for clinical diagnosis in the future. - Graphical abstract: A novel strategy using AgNPs-3D nanostructure enhanced electrochemiluminescence of CdSe quantum dot coupled with DNA strand displacement amplification for sensitive biosensing of DNA was successfully designed, the proposed biosensor can be expected to be an emerging alternative for straightforward nucleic acid detection in complex samples with an easy and rapid way. - Highlights: • AgNPs-3D nanostructure for enhancing ECL signal of CdSe QDs was successfully designed. • A new dual amplification strategy for detection of DNA by using AgNPs-3D nanostructure coupled with SDA was developed. • It is for the first time AgNPs-3D nanostructure

Folate decorated dual drug loaded nanoparticle: role of curcumin in enhancing therapeutic potential of nutlin-3a by reversing multidrug resistance.

Directory of Open Access Journals (Sweden)

Manasi Das

Full Text Available Retinoblastoma is the most common intraocular tumor in children. Malfunctioning of many signaling pathways regulating cell survival or apoptosis, make the disease more vulnerable. Notably, resistance to chemotherapy mediated by MRP-1, lung-resistance protein (LRP is the most challenging aspect to treat this disease. Presently, much attention has been given to the recently developed anticancer drug nutlin-3a because of its non-genotoxic nature and potency to activate tumor suppressor protein p53. However, being a substrate of multidrug resistance protein MRP1 and Pgp its application has become limited. Currently, research has step towards reversing Multi drug resistance (MDR by using curcumin, however its clinical relevance is restricted by plasma instability and poor bioavailability. In the present investigation we tried to encapsulate nutlin-3a and curcumin in PLGA nanoparticle (NPs surface functionalized with folate to enhance therapeutic potential of nutlin-3a by modulating MDR. We document that curcumin can inhibit the expression of MRP-1 and LRP gene/protein in a concentration dependent manner in Y79 cells. In vitro cellular cytotoxicity, cell cycle analysis and apoptosis studies were done to compare the effectiveness of native drugs (single or combined and single or dual drug loaded nanoparticles (unconjugated/folate conjugated. The result demonstrated an augmented therapeutic efficacy of targeted dual drug loaded NPs (Fol-Nut-Cur-NPs over other formulation. Enhanced expression or down regulation of proapoptotic/antiapoptotic proteins respectively and down-regulation of bcl2 and NFκB gene/protein by Fol-Nut-Cur-NPs substantiate the above findings. This is the first investigation exploring the role of curcumin as MDR modulator to enhance the therapeutic potentiality of nutlin-3a, which may opens new direction for targeting cancer with multidrug resistance phenotype.

Docetaxel-loaded multilayer nanoparticles with nanodroplets for cancer therapy.

Science.gov (United States)

Oh, Keun Sang; Kim, Kyungim; Yoon, Byeong Deok; Lee, Hye Jin; Park, Dal Yong; Kim, Eun-Yeong; Lee, Kiho; Seo, Jae Hong; Yuk, Soon Hong

2016-01-01

A mixture of docetaxel (DTX) and Solutol(®) HS 15 (Solutol) transiently formed nanodroplets when it was suspended in an aqueous medium. However, nanodroplets that comprised DTX and Solutol showed a rapid precipitation of DTX because of their unstable characteristics in the aqueous medium. The incorporation of nanodroplets that comprised DTX and Solutol through vesicle fusion and subsequent stabilization was designed to prepare multilayer nanoparticles (NPs) with a DTX-loaded Solutol nanodroplet (as template NPs) core for an efficient delivery of DTX as a chemotherapeutic drug. As a result, the DTX-loaded Solutol nanodroplets (~11.7 nm) were observed to have an increased average diameter (from 11.7 nm to 156.1 nm) and a good stability of the hydrated NPs without precipitation of DTX by vesicle fusion and multilayered structure, respectively. Also, a long circulation of the multilayer NPs was observed, and this was due to the presence of Pluronic F-68 on the surface of the multilayer NPs. This led to an improved antitumor efficacy based on the enhanced permeation and retention effect. Therefore, this study indicated that the multilayer NPs have a considerable potential as a drug delivery system with an enhanced therapeutic efficacy by blood circulation and with low side effects.

Surface modification of paclitaxel-loaded tri-block copolymer PLGA-b-PEG-b-PLGA nanoparticles with protamine for liver cancer therapy

Energy Technology Data Exchange (ETDEWEB)

Gao, Nansha [Chinese Academy of Science, Research Center for Human Tissues and Organs Degeneration, Shenzhen Institute of Advanced Technology (China); Chen, Zhihong [Guangdong Medical College, Analysis Centre (China); Xiao, Xiaojun [Shenzhen University, Institute of Allergy and Immunology, School of Medicine (China); Ruan, Changshun [Chinese Academy of Science, Research Center for Human Tissues and Organs Degeneration, Shenzhen Institute of Advanced Technology (China); Mei, Lin [Tsinghua University, The Shenzhen Key Lab of Gene and Antibody Therapy, and Division of Life and Health Sciences, Graduate School at Shenzhen (China); Liu, Zhigang, E-mail: lzg@szu.edu.cn [Shenzhen University, Institute of Allergy and Immunology, School of Medicine (China); Zeng, Xiaowei, E-mail: zeng.xiaowei@sz.tsinghua.edu.cn [Tsinghua University, The Shenzhen Key Lab of Gene and Antibody Therapy, and Division of Life and Health Sciences, Graduate School at Shenzhen (China)

2015-08-15

In order to enhance the therapeutic effect of chemotherapy on liver cancer, a biodegradable formulation of protamine-modified paclitaxel-loaded poly(lactide-co-glycolide)-b-poly(ethylene glycol)-b-poly(lactide-co-glycolide) (PLGA-b-PEG-b-PLGA) nanoparticles (PTX-loaded/protamine NPs) was prepared. Tri-block copolymer PLGA-b-PEG-b-PLGA was synthesized by ring-opening polymerization and characterized by {sup 1}H NMR spectroscopy and gel permeation chromatography. PTX-loaded and PTX-loaded/protamine NPs were characterized in terms of size, size distribution, zeta potential, surface morphology, drug encapsulation efficiency, and drug release. Confocal laser scanning microscopy showed that coumarin 6-loaded/protamine NPs were internalized by hepatocellular carcinoma cell line HepG2. The cellular uptake efficiency of NPs was obviously elevated after protamine modification. With commercial formulation Taxol{sup ®} as the reference, HepG2 cells were also used to study the cytotoxicity of the NPs. PTX-loaded/protamine NPs exhibited significantly higher cytotoxicity than PTX-loaded NPs and Taxol{sup ®} did. All the results suggested that surface modification of PTX-loaded PLGA-b-PEG-b-PLGA NPs with protamine boosted the therapeutic efficacy on liver cancer.

Kinetics of (3-aminopropyl)triethoxylsilane (APTES) silanization of superparamagnetic iron oxide nanoparticles.

Science.gov (United States)

Liu, Yue; Li, Yueming; Li, Xue-Mei; He, Tao

2013-12-10

Silanization of magnetic ironoxide nanoparticles with (3-aminopropyl)triethoxylsilane (APTES) is reported. The kinetics of silanization toward saturation was investigated using different solvents including water, water/ethanol (1/1), and toluene/methanol (1/1) at different reaction temperature with different APTES loading. The nanoparticles were characterized by Fourier transform infrared spectroscopy, vibrating sample magnetometry, transmission electron microscopy, and thermal gravimetric analysis (TGA). Grafting density data based on TGA were used for the kinetic modeling. It is shown that initial silanization takes place very fast but the progress toward saturation is very slow, and the mechanism may involve adsorption, chemical sorption, and chemical diffusion processes. The highest equilibrium grafting density of 301 mg/g was yielded when using toluene/methanol mixture as the solvent at a reaction temperature of 70 °C.

Hypericin-loaded nanoparticles for the photodynamic treatment of ovarian cancer.

Science.gov (United States)

Zeisser-Labouèbe, Magali; Lange, Norbert; Gurny, Robert; Delie, Florence

2006-12-01

A photodynamic approach has been suggested to improve diagnosis and therapy of ovarian cancer. As Hypericin (Hy), a natural photosensitizer (PS) extracted from Hypericum perforatum, has been shown to be efficient in vitro and in vivo for the detection or treatment of other cancers, Hy could also be a potent tool for the treatment and detection of ovarian cancer. Due to its hydrophobicity, systemic administration of Hy is problematic. Thus, polymeric nanoparticles (NPs) of polylactic acid (PLA) or polylactic-co-glycolic acid (PLGA) were used as a drug delivery system. Hy-loaded NPs were produced with the following characteristics: (i) size in the 200-300 nm range, (ii) negative zeta potential, (iii) low residual PVAL and (iv) drug loading from 0.03 to 0.15% (w/w). Their in vitro photoactivity was investigated on the NuTu-19 ovarian cancer cell model derived from Fischer 344 rats and compared to free drug. Hy-loaded PLA NPs exhibited a higher photoactivity than free drug. Increasing light dose or incubation time with cells induced an enhanced activity of Hy-loaded PLA NPs. Increased NP drug loading had a negative effect on their photoactivity on NuTu-19 cells: at the same Hy concentration, the higher was the drug loading, the lower was the phototoxic effect. The influence of NP drug loading on the Hy release from NPs was also investigated.

Transient loading of CD34+ hematopoietic progenitor cells with polystyrene nanoparticles.

Science.gov (United States)

Deville, Sarah; Hadiwikarta, Wahyu Wijaya; Smisdom, Nick; Wathiong, Bart; Ameloot, Marcel; Nelissen, Inge; Hooyberghs, Jef

2017-01-01

CD34 + hematopoietic progenitor cells (HPCs) offer great opportunities to develop new treatments for numerous malignant and non-malignant diseases. Nanoparticle (NP)-based strategies can further enhance this potential, and therefore a thorough understanding of the loading behavior of HPCs towards NPs is essential for a successful application. The present study focusses on the interaction kinetics of 40 nm sized carboxylated polystyrene (PS) NPs with HPCs. Interestingly, a transient association of the NPs with HPCs is observed, reaching a maximum within 1 hour and declining afterwards. This behavior is not seen in dendritic cells (CD34-DCs) differentiated from HPCs, which display a monotonic increase in NP load. We demonstrate that this transient interaction requires an energy-dependent cellular process, suggesting active loading and release of NPs by HPCs. This novel observation offers a unique approach to transiently equip HPCs. A simple theoretical approach modeling the kinetics of NP loading and release is presented, contributing to a framework of describing this phenomenon.

Promising biocidal activity of thymol loaded chitosan silver nanoparticles (T-C@AgNPs) as anti-infective agents against perilous pathogens.

Science.gov (United States)

Manukumar, H M; Umesha, S; Kumar, H N Naveen

2017-09-01

The advent of biodegradable polymer-encapsulated drug nanoparticles has made an exciting area of drug delivery research. The present study investigated novel and simple route for synthesis of thymol loaded chitosan silver nanoparticles (T-C@AgNPs) using chitosan and thymol as reducing, capping agent respectively to understand the therapeutic efficacy. The UV-vis spectroscopy, DLS, FT-IR, SEM, EDS, XRD used for characterization and radical scavenging activity, anti-microbial and biocompatibility was taken to ascertain an efficacy of novel T-C@AgNPs. The T-C@AgNPs intense peak at 490nm indicates the formation of nanoparticles and had average particle size of 28.94nm with spherical shape, monodisperse state in water, also exhibited excellent biocompatibility of cubic shaped pure silver element containing T-C@AgNPs. The antibacterial activity was studied for gram positive and gram negative food-borne pathogens and effective inhibition at 100μgmL -1 to S. aureus, S. epidermidis, S. haemolyticus (10.08, 10.00, 11.23mm) and S. typhimurium, P. aeruginosa and S. flexneri (9.28, 9.33, 12.03mm) compared to antibiotic Streptomycin. This study revealed the efficacy against multiple food-borne pathogens and therapeutic efficacy of T-C@AgNPs offers a valuable contribution in the area of nanotechnology. This proved to be a first-class novel antimicrobial material for the first time in this study. Copyright © 2017 Elsevier B.V. All rights reserved.

APT cost scaling: Preliminary indications from a Parametric Costing Model (PCM)

International Nuclear Information System (INIS)

Krakowski, R.A.

1995-01-01

A Parametric Costing Model has been created and evaluate as a first step in quantitatively understanding important design options for the Accelerator Production of Tritium (APT) concept. This model couples key economic and technical elements of APT in a two-parameter search of beam energy and beam power that minimizes costs within a range of operating constraints. The costing and engineering depth of the Parametric Costing Model is minimal at the present open-quotes entry levelclose quotes, and is intended only to demonstrate a potential for a more-detailed, cost-based integrating design tool. After describing the present basis of the Parametric Costing Model and giving an example of a single parametric scaling run derived therefrom, the impacts of choices related to resistive versus superconducting accelerator structures and cost of electricity versus plant availability (open-quotes load curveclose quotes) are reported. Areas of further development and application are suggested

Amtrak performance tracking (APT) system : methodology summary

Science.gov (United States)

2017-09-15

The Volpe Center collaborated with Amtrak and the Federal Railroad Administration (FRA) to develop a cost accounting system named Amtrak Performance Tracking (APT) used by Amtrak to manage, allocate, and report its costs. APTs initial development ...

Ciprofloxacin-loaded PLGA nanoparticles against cystic fibrosis P. aeruginosa lung infections.

Science.gov (United States)

Günday Türeli, Nazende; Torge, Afra; Juntke, Jenny; Schwarz, Bianca C; Schneider-Daum, Nicole; Türeli, Akif Emre; Lehr, Claus-Michael; Schneider, Marc

2017-08-01

Current pulmonary treatments against Pseudomonas aeruginosa infections in cystic fibrosis (CF) lung suffer from deactivation of the drug and immobilization in thick and viscous biofilm/mucus blend, along with the general antibiotic resistance. Administration of nanoparticles (NPs) with high antibiotic load capable of penetrating the tight mesh of biofilm/mucus can be an advent to overcome the treatment bottlenecks. Biodegradable and biocompatible polymer nanoparticles efficiently loaded with ciprofloxacin complex offer a solution for emerging treatment strategies. NPs were prepared under controlled conditions by utilizing MicroJet Reactor (MJR) to yield a particle size of 190.4±28.6nm with 0.089 PDI. Encapsulation efficiency of the drug was 79% resulting in a loading of 14%. Release was determined to be controlled and medium-independent in PBS, PBS+0.2% Tween 80 and simulated lung fluid. Cytotoxicity assays with Calu-3 cells and CF bronchial epithelial cells (CFBE41o - ) indicated that complex-loaded PLGA NPs were non-toxic at concentrations ≫ MIC cipro against lab strains of the bacteria. Antibacterial activity tests revealed enhanced activity when applied as nanoparticles. NPs' colloidal stability in mucus was proven. Notably, a decrease in mucus turbidity was observed upon incubation with NPs. Herewith, ciprofloxacin complex-loaded PLGA NPs are introduced as promising pulmonary nano drug delivery systems against P.aeruginosa infections in CF lung. Copyright © 2017 Elsevier B.V. All rights reserved.

The Effect of Superparamagnetic Iron Oxide Nanoparticle Surface Charge on Antigen Cross-Presentation

Science.gov (United States)

Mou, Yongbin; Xing, Yun; Ren, Hongyan; Cui, Zhihua; Zhang, Yu; Yu, Guangjie; Urba, Walter J.; Hu, Qingang; Hu, Hongming

2017-01-01

Magnetic nanoparticles (NPs) of superparamagnetic iron oxide (SPIO) have been explored for different kinds of applications in biomedicine, mechanics, and information. Here, we explored the synthetic SPIO NPs as an adjuvant on antigen cross-presentation ability by enhancing the intracellular delivery of antigens into antigen presenting cells (APCs). Particles with different chemical modifications and surface charges were used to study the mechanism of action of antigen delivery. Specifically, two types of magnetic NPs, γFe2O3/APTS (3-aminopropyltrimethoxysilane) NPs and γFe2O3/DMSA (meso-2, 3-Dimercaptosuccinic acid) NPs, with the same crystal structure, magnetic properties, and size distribution were prepared. Then, the promotion of T-cell activation via dendritic cells (DCs) was compared among different charged antigen coated NPs. Moreover, the activation of the autophagy, cytosolic delivery of the antigens, and antigen degradation mediated by the proteasome and lysosome were measured. Our results indicated that positive charged γFe2O3/APTS NPs, but not negative charged γFe2O3/DMSA NPs, enhanced the cross-presentation ability of DCs. Increased cross-presentation ability induced by γFe2O3/APTS NPs was associated with increased cytosolic antigen delivery. On the contrary, γFe2O3/DMSA NPs was associated with rapid autophagy. Overall, our results suggest that antigen delivered in cytoplasm induced by positive charged particles is beneficial for antigen cross-presentation and T-cell activation. NPs modified with different chemistries exhibit diverse biological properties and differ greatly in their adjuvant potentials. Thus, it should be carefully considered many different effects of NPs to design effective and safe adjuvants.

APT accelerator. Topical report

International Nuclear Information System (INIS)

Lawrence, G.; Rusthoi, D.

1995-03-01

The Accelerator Production of Tritium (APT) project, sponsored by Department of Energy Defense Programs (DOE/DP), involves the preconceptual design of an accelerator system to produce tritium for the nation's stockpile of nuclear weapons. Tritium is an isotope of hydrogen used in nuclear weapons, and must be replenished because of radioactive decay (its half-life is approximately 12 years). Because the annual production requirements for tritium has greatly decreased since the end of the Cold War, an alternative approach to reactors for tritium production, based on a linear accelerator, is now being seriously considered. The annual tritium requirement at the time this study was undertaken (1992-1993) was 3/8 that of the 1988 goal, usually stated as 3/8-Goal. Continued reduction in the number of weapons in the stockpile has led to a revised (lower) production requirement today (March, 1995). The production requirement needed to maintain the reduced stockpile, as stated in the recent Nuclear Posture Review (summer 1994) is approximately 3/16-Goal, half the previous level. The Nuclear Posture Review also requires that the production plant be designed to accomodate a production increase (surge) to 3/8-Goal capability within five years, to allow recovery from a possible extended outage of the tritium plant. A multi-laboratory team, collaborating with several industrial partners, has developed a preconceptual APT design for the 3/8-Goal, operating at 75% capacity. The team has presented APT as a promising alternative to the reactor concepts proposed for Complex-21. Given the requirements of a reduced weapons stockpile, APT offers both significant safety, environmental, and production-fexibility advantages in comparison with reactor systems, and the prospect of successful development in time to meet the US defense requirements of the 21st Century

APT accelerator. Topical report

Energy Technology Data Exchange (ETDEWEB)

Lawrence, G.; Rusthoi, D. [comp.] [ed.

1995-03-01

The Accelerator Production of Tritium (APT) project, sponsored by Department of Energy Defense Programs (DOE/DP), involves the preconceptual design of an accelerator system to produce tritium for the nation`s stockpile of nuclear weapons. Tritium is an isotope of hydrogen used in nuclear weapons, and must be replenished because of radioactive decay (its half-life is approximately 12 years). Because the annual production requirements for tritium has greatly decreased since the end of the Cold War, an alternative approach to reactors for tritium production, based on a linear accelerator, is now being seriously considered. The annual tritium requirement at the time this study was undertaken (1992-1993) was 3/8 that of the 1988 goal, usually stated as 3/8-Goal. Continued reduction in the number of weapons in the stockpile has led to a revised (lower) production requirement today (March, 1995). The production requirement needed to maintain the reduced stockpile, as stated in the recent Nuclear Posture Review (summer 1994) is approximately 3/16-Goal, half the previous level. The Nuclear Posture Review also requires that the production plant be designed to accomodate a production increase (surge) to 3/8-Goal capability within five years, to allow recovery from a possible extended outage of the tritium plant. A multi-laboratory team, collaborating with several industrial partners, has developed a preconceptual APT design for the 3/8-Goal, operating at 75% capacity. The team has presented APT as a promising alternative to the reactor concepts proposed for Complex-21. Given the requirements of a reduced weapons stockpile, APT offers both significant safety, environmental, and production-fexibility advantages in comparison with reactor systems, and the prospect of successful development in time to meet the US defense requirements of the 21st Century.

The APT model as reduced-rank regression

NARCIS (Netherlands)

Bekker, P.A.; Dobbelstein, P.; Wansbeek, T.J.

Integrating the two steps of an arbitrage pricing theory (APT) model leads to a reduced-rank regression (RRR) model. So the results on RRR can be used to estimate APT models, making estimation very simple. We give a succinct derivation of estimation of RRR, derive the asymptotic variance of RRR

ASEAN plus Three (APT) As a Socializing Environment

DEFF Research Database (Denmark)

Zhang, Jiuan

2012-01-01

In East Asia, several formal and informal regional institutions have been established in the last several decades to promote regional integration. However, it is difficult to identify which is the dominant institution and determine how it is working. ASEAN Plus Three (APT), representing the first...... institutionalized effort to combine Northeast and Southeast Asia and further promote integration in this institutionally undeveloped region, is central to the regionalist view of international relations. 1 Moreover, China’ s approach to the establishment of APT and changes in its regional behavior have attracted...... scholarly attention. This article combines an empirical analysis of China’s approach to APT with a theoretical discussion of APT’ s institutional design in order to illustrate how APT is working as an environment of socialization in the context of regional integration....

Silver nanoparticles (AgNPs) biosynthesized using pod extract of Cola nitida enhances antioxidant activity and phytochemical composition of Amaranthus caudatus Linn

Science.gov (United States)

Azeez, Luqmon; Lateef, Agbaje; Adebisi, Segun A.

2017-02-01

This study investigates the influence of different concentrations of AgNPs biologically synthesized using pod extract of Cola nitida on antioxidant activity, phenolic contents, flavonoid contents and compositions of Amaranthus caudatus L. AgNPs of 25, 50, 75, 100 and 150 ppm were utilized in growing A. caudatus while water was used as control. Delayed germination for two days was observed for A. caudatus grown with 150 ppm of AgNPs, while others showed no difference. There were 43.3, 38.7, 26.7 and 6.48% improvements in the 2,2-diphenyl-1-picrylhydrazyl (DPPH) antioxidant activity of A. caudatus grown with 25, 50, 75 and 100 ppm of AgNPs, respectively, compared to control. Antioxidant activity of A. caudatus grown with AgNPs reduced with increase in the concentrations of AgNPs. A. caudatus grown with 50 ppm of AgNPs was the most potent with the least IC50 of 0.67 mg/ml. Significant improvements obtained for phenolic and flavonoid contents grown with AgNPs were concentration dependent. Enhancements of 21.9, 68.19, and 1.98% in phenolic contents were achieved in treatments with 25, 50 and 75 ppm AgNPs, respectively, while 32.58, 35.80, and 7.20% improvement in flavonoids were obtained for 25, 50 and 100 ppm treatments, respectively. Kaempferol and quercetin were the most abundant flavonoids in A. caudatus treated with 50 ppm of AgNPs, showing the highest flavonoid composition. This further confirms A. caudatus grown with 50 ppm of AgNPs as the most potent. This study has shown that concentration-dependent AgNPs can be used to boost antioxidant activity and phytochemical contents of vegetables.

Assessment of Alternative RF Linac Structures for APT

Energy Technology Data Exchange (ETDEWEB)

None

1997-03-26

The APT program has been examining both normal and superconducting variants of the APT linac for the past two years. A decision on which of the two will be the selected technology will depend upon several considerations including the results of ongoing feasibility experiments, the performance and overall attractiveness of each of the design concepts, and an assessment of the system-level features of both alternatives. The primary objective of the Assessment of Alternative RF Linac Structures for APT study reported herein was to assess and compare, at the system-level, the performance, capital and life cycle costs, reliability/availability/maintainability (RAM) and manufacturing schedules of APT RF linear accelerators based upon both superconducting and normal conducting technologies. A secondary objective was to perform trade studies to explore opportunities for system optimization, technology substitution and alternative growth pathways and to identify sensitivities to design uncertainties.

Assessment of Alternative RF Linac Structures for APT

International Nuclear Information System (INIS)

None

1997-01-01

The APT program has been examining both normal and superconducting variants of the APT linac for the past two years. A decision on which of the two will be the selected technology will depend upon several considerations including the results of ongoing feasibility experiments, the performance and overall attractiveness of each of the design concepts, and an assessment of the system-level features of both alternatives. The primary objective of the Assessment of Alternative RF Linac Structures for APT study reported herein was to assess and compare, at the system-level, the performance, capital and life cycle costs, reliability/availability/maintainability (RAM) and manufacturing schedules of APT RF linear accelerators based upon both superconducting and normal conducting technologies. A secondary objective was to perform trade studies to explore opportunities for system optimization, technology substitution and alternative growth pathways and to identify sensitivities to design uncertainties

APT accelerator technology

International Nuclear Information System (INIS)

Schneider, J. David

1996-01-01

The proposed accelerator production of tritium (APT) project requires an accelerator that provides a cw proton beam of 100 m A at 1300 MeV. Since the majority of the technical risk of a high-current cw (continuous-wave, 100% DF) accelerator resides in the low-energy section, Los Alamos is building a 20 MeV duplicate of the accelerator front end to confirm design codes, beam performance, and demonstrate operational reliability. We report on design details of this low-energy demonstration accelerator (LEDA) and discuss the integrated design of the full accelerator for the APT plant. LEDA's proton injector is under test and has produced more than 130 mA at 75 keV. Fabrication is proceeding on a 6.7- MeV, 8-meter-long RFQ, and detailed design is underway on coupled-cavity drift-tube linac (CCDTL) structures. In addition, detailed design and technology experiments are underway on medium-beta superconducting cavities to assess the feasibility of replacing the conventional (room-temperature copper) high-energy linac with a linac made of niobium superconducting RF cavities. (author)

Docetaxel (DTX)-loaded polydopamine-modified TPGS-PLA nanoparticles as a targeted drug delivery system for the treatment of liver cancer.

Science.gov (United States)

Zhu, Dunwan; Tao, Wei; Zhang, Hongling; Liu, Gan; Wang, Teng; Zhang, Linhua; Zeng, Xiaowei; Mei, Lin

2016-01-01

Polydopamine-based surface modification is a simple way to functionalize polymeric nanoparticle (NP) surfaces with ligands and/or additional polymeric layers. In this work, we developed DTX-loaded formulations using polydopamine-modified NPs synthesized using D-α-tocopherol polyethylene glycol 1000 succinate-poly(lactide) (pD-TPGS-PLA/NPs). To target liver cancer cells, galactosamine was conjugated on the prepared NPs (Gal-pD-TPGS-PLA/NPs) to enhance the delivery of DTX via ligand-mediated endocytosis. The size and morphology of pD-TPGS-PLA/NPs and Gal-pD-TPGS-PLA/NPs changed obviously compared with TPGS-PLA/NPs. In vitro studies showed that TPGS-PLA/NPs, pD-TPGS-PLA/NPs and Gal-pD-TPGS-PLA/NPs had similar release profiles of DTX. Both confocal laser scanning microscopy and flow cytometric results showed that coumarin 6-loaded Gal-pD-TPGS-PLA/NPs had the highest cellular uptake efficiency in liver cancer cell line HepG2. Moreover, DTX-loaded Gal-pD-TPGS-PLA/NPs inhibited the growth of HepG2 cells more potently than TPGS-PLA/NPs, pD-TPGS-PLA/NPs, and a clinically available DTX formulation (Taxotere®). The in vivo biodistribution experiments show that the Gal-pD-TPGS-PLA/NPs are specifically targeted to the tumor. Furthermore, the in vivo anti-tumor effects study showed that injecting DTX-loaded Gal-pD-TPGS-PLA/NPs reduced the tumor size most significantly on hepatoma-bearing nude mice. These results suggest that Gal-pD-TPGS-PLA/NPs prepared in the study specifically interacted with the hepatocellular carcinoma cells through ligand-receptor recognition and they may be used as a potentially eligible drug delivery system targeting liver cancers. Polydopamine-based surface modification is a simple way to functionalize polymeric nanoparticle surfaces with ligands and/or additional polymeric layers. In this work, we developed docetaxel (DTX)-loaded formulations using polydopamine-modified NPs synthesized from D-α-tocopherol polyethylene glycol 1000 succinate

Lactobionic acid-conjugated TPGS nanoparticles for enhancing therapeutic efficacy of etoposide against hepatocellular carcinoma

Science.gov (United States)

Tsend-Ayush, Altansukh; Zhu, Xiumei; Ding, Yu; Yao, Jianxu; Yin, Lifang; Zhou, Jianping; Yao, Jing

2017-05-01

Many effective anti-cancer drugs have limited use in hepatocellular carcinoma (HCC) therapy due to the drug resistance mechanisms in liver cells. In recent years, tumor-targeted drug delivery and the inhibition of drug-resistance-related mechanisms has become an integrated strategy for effectively combating chemo-resistant cancer. Herein, lactobionic acid-conjugated d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS-LA conjugate) has been developed as a potential asialoglycoprotein receptor (ASGPR)-targeted nanocarrier and an efficient inhibitor of P-glycoprotein (P-gp) to enhance etoposide (ETO) efficacy against HCC. The main properties of ETO-loaded TPGS-LA nanoparticles (NPs) were tested through in vitro and in vivo studies after being prepared using the nanoprecipitation method and characterized by dynamic light scattering (DLS). According to the results, smaller (˜141.43 nm), positively charged ETO-loaded TPGS-LA NPs were more suitable for providing efficient delivery to hepatoma cells by avoiding the clearance mechanisms. It was found that ETO-loaded TPGS-LA NPs were noticeably able to enhance the cytotoxicity of ETO in HepG2 cells. Besides this, markedly higher internalization by the ASGPR-overexpressed HepG2 cells and efficient accumulation at the tumor site in vivo were revealed in the TPGS-LA NP group. More importantly, animal studies confirmed that ETO-loaded TPGS-LA NPs achieved the highest therapeutic efficacy against HCC. Interestingly, ETO-loaded TPGS-LA NPs also exhibited a great inhibitory effect on P-gp compared to the ETO-loaded TPGS NPs. These results suggest that TPGS-LA NPs could be used as a potential ETO delivery system against HCC.

Apte, Dr Shree Kumar

Indian Academy of Sciences (India)

Elected: 2008 Section: General Biology. Apte, Dr Shree Kumar Ph.D. (Gujarat), FNA, FNASc, FNAAS. Date of birth: 18 October 1952. Specialization: Molecular Biology & Biotechnology, Physiology and Stress Biology of Bacteria & Plants Address: Emeritus Professor, Homi Bhabha National Institute, Anushakti Nagar, ...

Constructing APT Attack Scenarios Based on Intrusion Kill Chain and Fuzzy Clustering

Directory of Open Access Journals (Sweden)

Ru Zhang

2017-01-01

Full Text Available The APT attack on the Internet is becoming more serious, and most of intrusion detection systems can only generate alarms to some steps of APT attack and cannot identify the pattern of the APT attack. To detect APT attack, many researchers established attack models and then correlated IDS logs with the attack models. However, the accuracy of detection deeply relied on the integrity of models. In this paper, we propose a new method to construct APT attack scenarios by mining IDS security logs. These APT attack scenarios can be further used for the APT detection. First, we classify all the attack events by purpose of phase of the intrusion kill chain. Then we add the attack event dimension to fuzzy clustering, correlate IDS alarm logs with fuzzy clustering, and generate the attack sequence set. Next, we delete the bug attack sequences to clean the set. Finally, we use the nonaftereffect property of probability transfer matrix to construct attack scenarios by mining the attack sequence set. Experiments show that the proposed method can construct the APT attack scenarios by mining IDS alarm logs, and the constructed scenarios match the actual situation so that they can be used for APT attack detection.

Towards Understanding Tyre-Pavement Contact in APT Research on Flexible Pavements

CSIR Research Space (South Africa)

De Beer, Morris

2016-09-01

Full Text Available An important element of Accelerated Pavement Testing (APT) is the selection of appropriate test tyre(s) to be used for APT testing. By far the majority of full scale (or scaled) APT devices uses pneumatic rubber tyres. Tyres differ not only in size...

A rapid-acting, long-acting insulin formulation based on a phospholipid complex loaded PHBHHx nanoparticles.

Science.gov (United States)

Peng, Qiang; Zhang, Zhi-Rong; Gong, Tao; Chen, Guo-Qiang; Sun, Xun

2012-02-01

The application of poly(hydroxybutyrate-co-hydroxyhexanoate) (PHBHHx) for sustained and controlled delivery of hydrophilic insulin was made possible by preparing insulin phospholipid complex loaded biodegradable PHBHHx nanoparticles (INS-PLC-NPs). The INS-PLC-NPs produced by a solvent evaporation method showed a spherical shape with a mean particle size, zeta potential and entrapment efficiency of 186.2 nm, -38.4 mv and 89.73%, respectively. In vitro studies demonstrated that only 20% of insulin was released within 31 days with a burst release of 5.42% in the first 8 h. The hypoglycaemic effect in STZ induced diabetic rats lasted for more than 3 days after the subcutaneous injection of INS-PLC-NPs, which significantly prolonged the therapeutic effect compared with the administration of insulin solution. The pharmacological bioavailability (PA) of INS-PLC-NPs relative to insulin solution was over 350%, indicating that the bioavailability of insulin was significantly enhanced by INS-PLC-NPs. Therefore, the INS-PLC-NPs system is promising to serve as a long lasting insulin release formulation, by which the patient compliance can be enhanced significantly. This study also showed that phospholipid complex loaded biodegradable nanoparticles (PLC-NPs) have a great potential to be used as a sustained delivery system for hydrophilic proteins to be encapsulated in hydrophobic polymers. Copyright © 2011 Elsevier Ltd. All rights reserved.

NiS(NPs)-PEDOT-PSS composite counter electrode for a high efficiency dye sensitized solar cell

Energy Technology Data Exchange (ETDEWEB)

Maiaugree, Wasan [Integrated Nanotechnology Research Center, Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Center for Alternative Energy Research and Development, Khon Kaen University, Khon Kaen 40002 (Thailand); Pimparue, Pachara; Jarernboon, Wirat [Integrated Nanotechnology Research Center, Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Pimanpang, Samuk [Department of Physics, Faculty of Science, Srinakharinwirot University, Bangkok 10110 (Thailand); Amornkitbamrung, Vittaya [Integrated Nanotechnology Research Center, Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Swatsitang, Ekaphan, E-mail: ekaphan@kku.ac.th [Integrated Nanotechnology Research Center, Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Center for Alternative Energy Research and Development, Khon Kaen University, Khon Kaen 40002 (Thailand)

2017-06-15

Graphical abstract: Figure(a) and (b) represent models depict PEDOT-PSS counter electrodes of DSSC without and with NiS NPs modification, respectively. The active surface area of PEDOT-PSS polymer can be improved by combining with NiS(NPs). The I-V curves in figure (c) show the superior photovoltaic conversion efficiency of 8.18% for NiS(NPs)/PEDOT-PSS DSSC. - Highlights: • Active surface area of PEDOT-PSS CE can be improved by mixing with NiS(NPs). • Electrocatalytic activity of mixed NiS(NPs)/PEDOT-PSS polymer is also improved. • NiS(NPs)/PEDOT-PSS CE shows a very low charge transfer resistance of 0.46 Ω. • In this work, the high photovoltaic conversion efficiency of 8.18% is achieved. - Abstract: Nickel sulfide (NiS) nanoparticles (NPs) (NiS(NPs)) were prepared by the hydrothermal method. X-ray diffraction (XRD) results indicate the hexagonal structure of NiS(NPs). SEM micrographs reveal the agglomeration of irregular hexagonal – shaped NiS(NPs) with estimated particle size in the range of 50–150 nm. Counter electrodes (CEs) of dye-sensitized solar cells (DSSCs) were prepared by coating the composite slurry of different NiS(NPs) loadings and Poly (3, 4-Ethylendioxythiophene) – Poly (Styrene Sulfonate) (PEDOT-PSS) on fluoride-doped tin oxide (FTO) substrates using a doctor blading technique. Cyclic voltammetry (CV) results indicate that the composites of NiS(NPs) and PEDOT-PSS (NiS(NPs)/PEDOT-PSS) films could function as a catalyst for I{sub 3}{sup −} reduction with a maximum cell efficiency of 8.18% for a cell of 0.3 g NiS(NPs) loading.

Radiation damage calculations for the APT materials test program

International Nuclear Information System (INIS)

Corzine, R.K.; Wechsler, M.S.; Dudziak, D.J.; Ferguson, P.D.; James, M.R.

1999-01-01

A materials irradiation was performed at the Los Alamos Neutron Science Center (LANSCE) in the fall of 1996 and spring of 1997 in support of the Accelerator Production of Tritium (APT) program. Testing of the irradiated materials is underway. In the proposed APT design, materials in the target and blanket are to be exposed to protons and neutrons over a wide range of energies. The irradiation and testing program was undertaken to enlarge the very limited direct knowledge presently available of the effects of medium-energy protons (∼1 GeV) on the properties of engineering materials. APT candidate materials were placed in or near the LANSCE accelerator 800-MeV, 1-mA proton beam and received roughly the same proton current density in the center of the beam as would be the case for the APT facility. As a result, the proton fluences achieved in the irradiation were expected to approach the APT prototypic full-power-year values. To predict accurately the performance of materials in APT, radiation damage parameters for the materials experiment must be determined. By modeling the experiment, calculations for atomic displacement, helium and hydrogen cross sections and for proton and neutron fluences were done for representative samples in the 17A, 18A, and 18C areas. The LAHET code system (LCS) was used to model the irradiation program, LAHET 2.82 within LCS transports protons > 1 MeV, and neutrons >20 MeV. A modified version of MCNP for use in LCS, HMCNP 4A, was employed to tally neutrons of energies <20 MeV

Expected Impact of Agricultural Nonpoint Sources Special Land Treatment (AgNPS-SALT) Projects

OpenAIRE

Anonymous

2006-01-01

This set of reports describes the computer based evaluation of 6 AgNPS-SALT Projects in Missouri and assesses the use of SWAT as an evaluation tool. The analyses estimates nutrient, sediment, and pesticide loading reductions for each project. Titles include: Final Report, Computer Based Evaluation of the AgNPS-SALT Project (19-06); Long Branch Lake Watershed, Computer Based Evaluation of the AgNPS-SALT Project (20-06); Upper and Lower Big Maries River Watersheds Computer Based Evaluation of t...

An efficient sodium citrate-promoted synthetic method for the preparation of AuNPs@mesoSiO2 for surface enhanced Raman spectroscopy in the detection of diluted blood

Directory of Open Access Journals (Sweden)

Yun Zou

2017-12-01

Full Text Available We report on a novel, green, and efficient organically synthetic method for the preparation of gold nanoparticles embedded in mesoporous silica (AuNPs@mesoSiO2. AuNPs@mesoSiO2 prepared by one-pot synthesis method using sodium citrate as the key reactant was applied for surface enhanced Raman spectroscopy (SERS application in the analysis of diluted blood traces. The synthesized nanoparticles are of high quality, as characterized by use of X-ray diffraction, scanning electron microscopy and transmission electron microscopy. They exhibit high surface areas (170.18–883 m2/g and significant SERS enhancement. Detection of diluted blood (v/v, 1:50 traces through AuNPs@mesoSiO2 enhanced SERS is demonstrated, which has not been studied in previous literature. The combination of the SERS and AuNPs@mesoSiO2 would be a valuable tool for forensic investigation. Keywords: Gold nanoparticles, Mesoporous materials, Synthesis, SERS, Blood trace

Update NPS / August 2017

OpenAIRE

Naval Postgraduate School (U.S.)

2017-01-01

Fleet Forces Commander Encourages Student Body to Embrace Change; NPS Honors Longtime ECE, Space Systems Professor Herschel Loomis; NPS Welcomes Alumnus, Cartoonist Capt. Jeff Bacon; Student-Designed Wave Generator Gives Old Research Tank New Life; NPS Honored With Chief of Naval Operations Safety Award; NPS Faculty Publishes Latest Book on Budgeting in the DOD; NPS Sailor Promotes Through Meritorious Advancement Program; NPS Student Completes DARPA Service Chiefs Fellowship

An aptamer-based fluorescence bio-sensor for chiral recognition of arginine enantiomers.

Science.gov (United States)

Yuan, Haiyan; Huang, Yunmei; Yang, Jidong; Guo, Yuan; Zeng, Xiaoqing; Zhou, Shang; Cheng, Jiawei; Zhang, Yuhui

2018-07-05

In this study, a novel aptamer - based fluorescence bio-sensor (aptamer-AuNps) was developed for chiral recognition of arginine (Arg) enantiomers based on aptamer and gold nanoparticles (AuNps). Carboxyfluorescein (FAM) labeled aptamers (Apt) were absorbed on AuNps and their fluorescence intensity could be significantly quenched by AuNps based on fluorescence resonance energy transfer (FRET). Once d-Arg or l-Arg were added into the above solution, the aptamer specifically bind to Arg enantiomers and released from AuNps, so the fluorescence intensity of d-Arg system and l-Arg system were all enhanced. The affinity of Apt to l-Arg is tighter to d-Arg, so the enhanced fluorescence signals of l-Arg system was stronger than d-Arg system. What's more, the enhanced fluorescence were directly proportional to the concentration of d-Arg and l-Arg ranging from 0-300 nM and 0-400 nM with related coefficients of 0.9939 and 0.9952, respectively. Furthermore, the method was successfully applied to detection l-Arg in human urine samples with satisfactory results. Eventually, a simple "OR" logic gate with d-Arg &l-Arg as inputs and AuNps aggregation state as outputs was fabricated, which can help us understand the chiral recognition process deeply. Copyright © 2018 Elsevier B.V. All rights reserved.

Docetaxel-loaded multilayer nanoparticles with nanodroplets for cancer therapy

Directory of Open Access Journals (Sweden)

Oh KS

2016-03-01

Full Text Available Keun Sang Oh,1,* Kyungim Kim,1,* Byeong Deok Yoon,1 Hye Jin Lee,1 Dal Yong Park,1 Eun-yeong Kim,1 Kiho Lee,1 Jae Hong Seo,2 Soon Hong Yuk1,2 1College of Pharmacy, Korea University, Sejong, 2Biomedical Research Center, Korea University Guro Hospital, Guro-gu, Seoul, Republic of Korea *These authors contributed equally to this work Abstract: A mixture of docetaxel (DTX and Solutol® HS 15 (Solutol transiently formed nanodroplets when it was suspended in an aqueous medium. However, nanodroplets that comprised DTX and Solutol showed a rapid precipitation of DTX because of their unstable characteristics in the aqueous medium. The incorporation of nanodroplets that comprised DTX and Solutol through vesicle fusion and subsequent stabilization was designed to prepare multilayer nanoparticles (NPs with a DTX-loaded Solutol nanodroplet (as template NPs core for an efficient delivery of DTX as a chemotherapeutic drug. As a result, the DTX-loaded Solutol nanodroplets (~11.7 nm were observed to have an increased average diameter (from 11.7 nm to 156.1 nm and a good stability of the hydrated NPs without precipitation of DTX by vesicle fusion and multilayered structure, respectively. Also, a long circulation of the multilayer NPs was observed, and this was due to the presence of Pluronic F-68 on the surface of the multilayer NPs. This led to an improved antitumor efficacy based on the enhanced permeation and retention effect. Therefore, this study indicated that the multilayer NPs have a considerable potential as a drug delivery system with an enhanced therapeutic efficacy by blood circulation and with low side effects. Keywords: multilayer nanoparticles, Solutol, Pluronic F-68, docetaxel, cancer therapy

Enhanced corrosion resistance and biocompatibility of AZ31 Mg alloy using PCL/ZnO NPs via electrospinning

Energy Technology Data Exchange (ETDEWEB)

Kim, Jinwoo [Department of Bionanosystem Engineering, Graduate School, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Mousa, Hamouda M. [Department of Bionanosystem Engineering, Graduate School, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Department of Engineering Materials and Mechanical Design, Faculty of Engineering, South Valley University, Qena 83523 (Egypt); Park, Chan Hee, E-mail: biochan@jbnu.ac.kr [Department of Bionanosystem Engineering, Graduate School, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Division of Mechanical Design Engineering, Chonbuk National University, Jeonju, Jeonbuk 561-756 (Korea, Republic of); Kim, Cheol Sang, E-mail: chskim@jbnu.ac.kr [Department of Bionanosystem Engineering, Graduate School, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Division of Mechanical Design Engineering, Chonbuk National University, Jeonju, Jeonbuk 561-756 (Korea, Republic of)

2017-02-28

Highlights: • PCL/ZnO composite coating layer by electrospinning techniques showed the nano-scaled and porous surface structure. • Addition of zinc oxide NPs in the PCL fibers led to enhanced coating adhesion and corrosion resistance. • The composite coated surfaces on Mg substrates improved cell attachment and proliferation. - Abstract: In the efforts to improve corrosion resistance and biocompatibility of magnesium alloys, polycarprolactone (PCL) and zinc oxide nanoparticles (ZnO NPs) composite coatings were applied onto AZ31 Mg alloys via electrospinning technique in this study. The PCL/ZnO composite coatings on Mg alloys were characterized by using FE-SEM, EDX, XPS, and FT-IR. Moreover, coating adhesion test, electrochemical corrosion test, and biocompatibility test in vitro were performed to measure coating performance. Our results revealed that the increase in the content of ZnO NPs in the composite coatings not only improved the coating adhesion of composite coatings on Mg alloys, but also increased the corrosion resistance. Furthermore, the biocompatibility of MC3T3-E1 osteoblasts of the PCL/ZnO composite coated samples was superior to the biocompatibility of the bare samples. Such data suggest that applying PCL/ZnO composite coating to the magnesium alloys has suitable potential in biomedical applications.

Enhanced corrosion resistance and biocompatibility of AZ31 Mg alloy using PCL/ZnO NPs via electrospinning

International Nuclear Information System (INIS)

Kim, Jinwoo; Mousa, Hamouda M.; Park, Chan Hee; Kim, Cheol Sang

2017-01-01

Highlights: • PCL/ZnO composite coating layer by electrospinning techniques showed the nano-scaled and porous surface structure. • Addition of zinc oxide NPs in the PCL fibers led to enhanced coating adhesion and corrosion resistance. • The composite coated surfaces on Mg substrates improved cell attachment and proliferation. - Abstract: In the efforts to improve corrosion resistance and biocompatibility of magnesium alloys, polycarprolactone (PCL) and zinc oxide nanoparticles (ZnO NPs) composite coatings were applied onto AZ31 Mg alloys via electrospinning technique in this study. The PCL/ZnO composite coatings on Mg alloys were characterized by using FE-SEM, EDX, XPS, and FT-IR. Moreover, coating adhesion test, electrochemical corrosion test, and biocompatibility test in vitro were performed to measure coating performance. Our results revealed that the increase in the content of ZnO NPs in the composite coatings not only improved the coating adhesion of composite coatings on Mg alloys, but also increased the corrosion resistance. Furthermore, the biocompatibility of MC3T3-E1 osteoblasts of the PCL/ZnO composite coated samples was superior to the biocompatibility of the bare samples. Such data suggest that applying PCL/ZnO composite coating to the magnesium alloys has suitable potential in biomedical applications.

Study on Synthesis and Antibacterial Properties of Ag NPs/GO Nanocomposites

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Lei Huang

2016-01-01

Full Text Available Using graphene oxide as substrate and stabilizer for the silver nanoparticles, silver nanoparticles-graphene oxide (Ag NPs/GO composites with different Ag loading were synthesized through a facile solution-phase method. During the synthesis process, AgNO3 on GO matrix was directly reduced by NaBH4. The structure characterization was studied through X-ray diffraction (XRD, atomic force microscopy (AFM, high-resolution transmission electron microscope (HRTEM, ultraviolet-visible spectroscopy (UV-Vis, and selected area electron diffraction (SAED. The results show that Ag nanoparticles (Ag NPs with the sizes ranging from 5 to 20 nm are highly dispersed on the surfaces of GO sheets. The shape and size of the Ag NPs are decided by the volume of initial AgNO3 solution added in the GO. The antibacterial activities of Ag NPs/GO nanocomposites were investigated and the result shows that all the produced composites exhibit good antibacterial activities against Gram-negative (G− bacterial strain Escherichia coli (E. coli and Gram-positive (G+ strain Staphylococcus aureus (S. aureus. Moreover, the antibacterial activities of Ag NPs/GO nanocomposites gradually increased with the increasing of volume of initial AgNO3 solution added in the GO and this improvement of the antibacterial activities results from the combined action of size effect and concentration effect of Ag NPs in Ag NPs/GO nanocomposites.

Transient loading of CD34+ hematopoietic progenitor cells with polystyrene nanoparticles

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Deville S

2017-01-01

Full Text Available Sarah Deville,1,2 Wahyu Wijaya Hadiwikarta,1 Nick Smisdom,1,2 Bart Wathiong,1,3 Marcel Ameloot,2 Inge Nelissen,1 Jef Hooyberghs1,3 1VITO, Flemish Institute for Technological Research, Mol, Belgium; 2Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium; 3Theoretical Physics, Hasselt University, Diepenbeek, Belgium Abstract: CD34+ hematopoietic progenitor cells (HPCs offer great opportunities to develop new treatments for numerous malignant and non-malignant diseases. Nanoparticle (NP-based strategies can further enhance this potential, and therefore a thorough understanding of the loading behavior of HPCs towards NPs is essential for a successful application. The present study focusses on the interaction kinetics of 40 nm sized carboxylated polystyrene (PS NPs with HPCs. Interestingly, a transient association of the NPs with HPCs is observed, reaching a maximum within 1 hour and declining afterwards. This behavior is not seen in dendritic cells (CD34-DCs differentiated from HPCs, which display a monotonic increase in NP load. We demonstrate that this transient interaction requires an energy-dependent cellular process, suggesting active loading and release of NPs by HPCs. This novel observation offers a unique approach to transiently equip HPCs. A simple theoretical approach modeling the kinetics of NP loading and release is presented, contributing to a framework of describing this phenomenon. Keywords: nanoparticles, hematopoietic progenitor cells, dendritic cells, uptake, release

Interrogation of duplicitous stars with an APT

Science.gov (United States)

Bopp, Bernard W.

1992-01-01

Preliminary results from intensive spectroscopic and APT monitoring of two interacting binary systems are presented. Both V644 Mon (Be + K:) and HD 37453 (F5 II + B) show complex, composite, and variable spectral. APT observations extending over three years show both stars to vary by 0.1-0.2 mag in V. The photometric variability of V644 Mon appears to be irregular, though there is some evidence for periodic behavior in the 50-60 day range. HD 37453 has an orbital period of 66.75 days; the best-fit photometric period is not quite half this value, indicating the star is an ellipsoidal variable.

PEG-lipid-PLGA hybrid nanoparticles loaded with berberine-phospholipid complex to facilitate the oral delivery efficiency.

Science.gov (United States)

Yu, Fei; Ao, Mingtao; Zheng, Xiao; Li, Nini; Xia, Junjie; Li, Yang; Li, Donghui; Hou, Zhenqing; Qi, Zhongquan; Chen, Xiao Dong

2017-11-01

The natural product berberine (BBR), present in various plants, arouses great interests because of its numerous pharmacological effects. However, the further development and application of BBR had been hampered by its poor oral bioavailability. In this work, we report on polymer-lipid hybrid nanoparticles (PEG-lipid-PLGA NPs) loaded with BBR phospholipid complex using a solvent evaporation method for enhancing the oral BBR efficiency. The advantage of this new drug delivery system is that the BBR-soybean phosphatidylcholine complex (BBR-SPC) could be used to enhance the liposolubility of BBR and improve the affinity with the biodegradable polymer to increase the drug-loading capacity and controlled/sustained release. The entrapment efficiency of the PEG-lipid-PLGA NPs/BBR-SPC was observed to approach approximately 89% which is more than 2.4 times compared with that of the PEG-lipid-PLGA NPs/BBR. To the best of our knowledge, this is the first report on using polymer material for effective encapsulation of BBR to improve its oral bioavailability. The prepared BBR delivery systems demonstrated a uniform spherical shape, a well-dispersed core-shell structure and a small particle size (149.6 ± 5.1 nm). The crystallographic and thermal analysis has indicated that the BBR dispersed in the PEG-lipid-PLGA NPs matrix is in an amorphous form. More importantly, the enhancement in the oral relative bioavailability of the PEG-lipid-PLGA NPs/BBR-SPC was ∼343% compared with that of BBR. These positive results demonstrated that PEG-lipid-PLGA NPs/BBR-SPC may have the potential for facilitating the oral drug delivery of BBR.

Confinement and Tritium Stripping Systems for APT Tritium Processing

Energy Technology Data Exchange (ETDEWEB)

Hsu, R.H. [Westinghouse Savannah River Company, AIKEN, SC (United States); Heung, L.K.

1997-10-20

This report identifies functions and requirements for the tritium process confinement and clean-up system (PCCS) and provides supporting technical information for the selection and design of tritium confinement, clean-up (stripping) and recovery technologies for new tritium processing facilities in the Accelerator for the Production of Tritium (APT). The results of a survey of tritium confinement and clean-up systems for large-scale tritium handling facilities and recommendations for the APT are also presented.

Confinement and Tritium Stripping Systems for APT Tritium Processing

International Nuclear Information System (INIS)

Hsu, R.H.; Heung, L.K.

1997-01-01

This report identifies functions and requirements for the tritium process confinement and clean-up system (PCCS) and provides supporting technical information for the selection and design of tritium confinement, clean-up (stripping) and recovery technologies for new tritium processing facilities in the Accelerator for the Production of Tritium (APT). The results of a survey of tritium confinement and clean-up systems for large-scale tritium handling facilities and recommendations for the APT are also presented

The preparation, characterization, and pharmacokinetic studies of chitosan nanoparticles loaded with paclitaxel/dimethyl-β-cyclodextrin inclusion complexes

Directory of Open Access Journals (Sweden)

Ye YJ

2015-07-01

Full Text Available Ya-Jing Ye,1 Yun Wang,1 Kai-Yan Lou,1 Yan-Zuo Chen,1 Rongjun Chen,2 Feng Gao1,3,4 1Department of Pharmaceutics, School of Pharmacy, East China University of Science and Technology, Shanghai, People’s Republic of China; 2Department of Chemical Engineering, Imperial College London, London, United Kingdom; 3Shanghai Key Laboratory of Functional Materials Chemistry, 4Shanghai Key Laboratory of New Drug Design, East China University of Science and Technology, Shanghai, People’s Republic of China Abstract: A novel biocompatible and biodegradable drug-delivery nanoparticle (NP has been developed to minimize the severe side effects of the poorly water-soluble anticancer drug paclitaxel (PTX for clinical use. PTX was loaded into the hydrophobic cavity of a hydrophilic cyclodextrin derivative, heptakis (2,6-di-O-methyl-β-cyclodextrin (DM-β-CD, using an aqueous solution-stirring method followed by lyophilization. The resulting PTX/DM-β-CD inclusion complex dramatically enhanced the solubility of PTX in water and was directly incorporated into chitosan (CS to form NPs (with a size of 323.9–407.8 nm in diameter using an ionic gelation method. The formed NPs had a zeta potential of +15.9–23.3 mV and showed high colloidal stability. With the same weight ratio of PTX to CS of 0.7, the loading efficiency of the PTX/DM-β-CD inclusion complex-loaded CS NPs was 30.3-fold higher than that of the PTX-loaded CS NPs. Moreover, it is notable that PTX was released from the DM-β-CD/CS NPs in a sustained-release manner. The pharmacokinetic studies revealed that, compared with reference formulation (Taxol®, the PTX/DM-β-CD inclusion complex-loaded CS NPs exhibited a significant increase in AUC0→24h (the area under the plasma drug concentration–time curve over the period of 24 hours and mean residence time by 2.7-fold and 1.4-fold, respectively. Therefore, the novel drug/DM-β-CD inclusion complex-loaded CS NPs have promising applications for the

Bovine serum albumin nanoparticles loaded with Photosens photosensitizer for effective photodynamic therapy

Science.gov (United States)

Khanadeev, Vitaly; Khlebtsov, Boris; Packirisamy, Gopinath; Khlebtsov, Nikolai

2017-03-01

Polymeric nanoparticles (NPs) are widely used for drug delivery applications due to high biodegradability, low toxicity and high loading capacity. The focus of this study is the development of photosensitizer Photosens (PS) loaded albumin NPs for efficient photodynamic therapy (PDT). To fabricate PS-loaded bovine serum albumin nanoparticles (BSA-PS NPs), we used a coacervation method with glutaraldehyde followed by passive loading of PS. Successful loading of PS was confirmed by appearance of characteristic peak in absorption spectrum which allows to determine the PS loading in BSA NPs. The synthesized BSA-PS NPs demonstrated low toxicity to HeLa cells at therapeutic concentrations of loaded PS. Compared to free PS solution, the synthesized BSA-PS NPs generated the singlet oxygen more effectively under laser irradiation at 660 nm. In addition, due to presence of various chemical groups on the surface of BSA-PS NPs, they are capable to adsorb on cell surface and accumulate in cells due to cellular uptake mechanisms. Owing to combination of PD and cell uptake advantages, BSA-PS NPs demonstrated higher efficacy of photodynamic damage to cancer cells as compared to free PS at equivalent concentrations. These results suggest that non-targeted BSA-PS NPs with high PD activity and low-fabrication costs of are promising candidates for transfer to PD clinic treatments.

Basis for low beam loss in the high-current APT linac

International Nuclear Information System (INIS)

Wangler, T.P.; Gray, E.R.; Krawczyk, F.L.; Kurennoy, S.S.; Lawrence, G.P.; Ryne, R.D.; Crandall, K.R.

1998-01-01

The present evidence that the APT proton linac design will meet its goal of low beam loss operation. The conclusion has three main bases: (1) extrapolation from the understanding of the performance of the 800-MeV LANSCE proton linac at Los Alamos, (2) the theoretical understanding of the dominant halo-forming mechanism in the APT accelerator from physics models and multiparticle simulations, and (3) the conservative approach and key principles underlying the design of the APT linac, which are aimed at minimizing beam halo and providing large apertures to reduce beam loss to a very low value

Testing APT Model upon a BVB Stocks’ Portfolio

Directory of Open Access Journals (Sweden)

Alexandra BONTAŞ

2011-01-01

Full Text Available Applying the Arbitrage Pricing Theory model (APT, there can be identified the major factors of influence for a BVB’ portfolio stocks' trend. There were taken into consideration two of the APT theory models, establishing influences upon portfolio's yield: given to macroeconomic environment and to some stochastic factors. The researchs results certify that, on the long term, what influences the stocks’ movement in the stock market is mostly the action of specific short-term factors, without general covering, like the ones that are classified in the research area of behavioral finance (investors’ preference towards risk and towards time.

Identifying APT Malware Domain Based on Mobile DNS Logging

Directory of Open Access Journals (Sweden)

Weina Niu

2017-01-01

Full Text Available Advanced Persistent Threat (APT is a serious threat against sensitive information. Current detection approaches are time-consuming since they detect APT attack by in-depth analysis of massive amounts of data after data breaches. Specifically, APT attackers make use of DNS to locate their command and control (C&C servers and victims’ machines. In this paper, we propose an efficient approach to detect APT malware C&C domain with high accuracy by analyzing DNS logs. We first extract 15 features from DNS logs of mobile devices. According to Alexa ranking and the VirusTotal’s judgement result, we give each domain a score. Then, we select the most normal domains by the score metric. Finally, we utilize our anomaly detection algorithm, called Global Abnormal Forest (GAF, to identify malware C&C domains. We conduct a performance analysis to demonstrate that our approach is more efficient than other existing works in terms of calculation efficiency and recognition accuracy. Compared with Local Outlier Factor (LOF, k-Nearest Neighbor (KNN, and Isolation Forest (iForest, our approach obtains more than 99% F-M and R for the detection of C&C domains. Our approach not only can reduce data volume that needs to be recorded and analyzed but also can be applicable to unsupervised learning.

Thermal analysis of the APT materials irradiation samples

International Nuclear Information System (INIS)

Maloy, S.A.; Willcutt, G.J.; James, M.R.; Teague, J.; Diebe, D.A.; Sommer, W.F.; Ferguson, P.D.

1998-01-01

The accelerator production of tritium (APT) project proposes to use a 1.7 GeV, 100 mA proton beam to produce neutrons from an Inconel 718 clad tungsten target. The neutrons are multiplied and moderated in a lead/water blanket before being captured in He 3 to form tritium. In this process, the materials in the target and blanket region are exposed to a wide range of different fluxes comprised of protons and neutrons with energies into the GeV range. To investigate the effect of irradiation on the mechanical properties of candidate APT materials (Inconel 718, 316L stainless steel, Al 6061-T6, Mod 9Cr-1Mo, 304L stainless steel and Al5052-0), the APT Engineering Design and Development group fielded an extensive materials irradiation using the LANSCE (Los Alamos Neutron Science Center) accelerator, which operates at an energy of 800 MeV and a current of 1 mA. The test set-up was designed to place mechanical test specimens in locations in and near the proton beam where the environment of proton and neutron fluxes and temperatures are prototypic to those expected in the APT target/blanket (50--170 C). After irradiating for about 3,600 hours, the maximum achieved proton fluence was 4--5 x 10 21 p/cm 2 for the materials in the center of the beam. To obtain relevant data on the change in the mechanical properties with fluence, it is essential to know the temperature at which the materials were irradiated. This paper explains the method of determining the specimen temperature and reports some specific examples

Effect of Zebularine loaded MePEG-PCL nanoparticles on viability, attachment of in vitro cultured lens epithelial cells

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Si-Wei Liu

2015-01-01

Full Text Available AIM: To investigate the effect of zebularine(Zebloaded Poly(ethylene glycol-block-poly(ε-caprolactonemethyl ether(MePEG-PCLnanoparticles(NPson the viability, attachment, and apoptosis of in vitro cultured lens epithelial cells(LECs. METHODS: In vitro cultured infant human lens tissue HLE B-3 immortalized cells were distributed randomly divided into six groups. Each group was administered with free Zeb 50μmol/L(ZebF1 group, 100μmol/L(ZebF2 group, Zeb -loaded MePEG-PCL NPs 50μmol/L(ZebNP1 group, Zeb -loaded MePEG-PCL NPs 100μmol/L(ZebNP2 group, MePEG-PCL empty NPs(NPs groupor blank medium(group Crespectively. A tetrazolium dye assay(MTTtest and modified MTT test were performed to determine cell viability and cell attachment. DNA ladder was used to detect the cell apoptosis. RESULTS: Determined by MTT colorimetric method: Cell proliferation rate of LECs were suppressed by all Zeb administration groups in a concentration-time dependent manner(PPP ZebNP1>ZebF2(PCONCLUSION: Zeb loaded MePEG-PCL NPs had better effect on suppressing the viability and attachment of in vitro cultured LECs than the free Zeb groups, as well as enhancing the apoptosis.

Enhanced anticancer activity and oral bioavailability of ellagic acid through encapsulation in biodegradable polymeric nanoparticles.

Science.gov (United States)

Mady, Fatma M; Shaker, Mohamed A

2017-01-01

Despite the fact that various studies have investigated the clinical relevance of ellagic acid (EA) as a naturally existing bioactive substance in cancer therapy, little has been reported regarding the efficient strategy for improving its oral bioavailability. In this study, we report the formulation of EA-loaded nanoparticles (EA-NPs) to find a way to enhance its bioactivity as well as bioavailability after oral administration. Poly(ε-caprolactone) (PCL) was selected as the biodegradable polymer for the formulation of EA-NPs through the emulsion-diffusion-evaporation technique. The obtained NPs have been characterized by measuring particle size, zeta potential, Fourier transform infrared, differential scanning calorimetry, and X-ray diffraction. The entrapment efficiency and the release profile of EA was also determined. In vitro cellular uptake and cytotoxicity of the obtained NPs were evaluated using Caco-2 and HCT-116 cell lines, respectively. Moreover, in vivo study has been performed to measure the oral bioavailability of EA-NPs compared to free EA, using New Zealand white rabbits. NPs with distinct shape were obtained with high entrapment and loading efficiencies. Diffusion-driven release profile of EA from the prepared NPs was determined. EA-NP-treated HCT-116 cells showed relatively lower cell viability compared to free EA-treated cells. Fluorometric imaging revealed the cellular uptake and efficient localization of EA-NPs in the nuclear region of Caco-2 cells. In vivo testing revealed that the oral administration of EA-NPs produced a 3.6 times increase in the area under the curve compared to that of EA. From these results, it can be concluded that incorporation of EA into PCL as NPs enhances its oral bioavailability and activity.

Silver nanoparticles-loaded activated carbon fibers using chitosan as binding agent: Preparation, mechanism, and their antibacterial activity

Energy Technology Data Exchange (ETDEWEB)

Tang, Chengli, E-mail: tcl-lily@mail.zjxu.edu.cn [College of Mechanical and Electrical Engineering, Jiaxing University, Jiaxing 314001 (China); Hu, Dongmei [College of Mechanical Science and Engineering, Jilin University, Changchun 130022 (China); Cao, Qianqian [College of Mechanical and Electrical Engineering, Jiaxing University, Jiaxing 314001 (China); Yan, Wei [Department of Environmental Science and Engineering, Xi’an Jiaotong University, Xi’an 710049 (China); Xing, Bo [College of Mechanical and Electrical Engineering, Jiaxing University, Jiaxing 314001 (China)

2017-02-01

Highlights: • Chitosan was firstly introduced as binding agent for AgNPs loading on ACF surface. • Molecular dynamics simulation was used to explore the AgNPs loading mechanism. • Loading mechanism was proposed based on the experimental and simulation results. • Antibacterial AgNPs-loaded ACF showed use potential for water disinfection. - Abstract: The effective and strong adherence of silver nanoparticles (AgNPs) to the substrate surface is pivotal to the practical application of those AgNPs-modified materials. In this work, AgNPs were synthesized through a green and facile hydrothermal method. Chitosan was introduced as the binding agent for the effective loading of AgNPs on activated carbon fibers (ACF) surface to fabricate the antibacterial material. Apart from conventional instrumental characterizations, i. e., scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), zeta potential and Brunauer-Emmett-Teller (BET) surface area measurement, molecular dynamics simulation method was also applied to explore the loading mechanism of AgNPs on the ACF surface. The AgNPs-loaded ACF material showed outstanding antibacterial activity for S. aureus and E. coli. The combination of experimental and theoretical calculation results proved chitosan to be a promising binding agent for the fabrication of AgNPs-loaded ACF material with excellent antibacterial activity.

Methodology for agricultural and rural NPS pollution in a typical county of the North China Plain

International Nuclear Information System (INIS)

Yang Yong; Chen Ying; Zhang Xiaolan; Ongley, Edwin; Zhao Lei

2012-01-01

Agricultural non-point source (NPS) pollution has been recently identified by the Chinese government as a major source of aquatic pollution. Methodologies commonly used to make basin-wide or area-wide assessments are problematic and regional distinctions have not been made relative to rainfall and runoff. Using a typical agricultural county in the Hai River basin of the North China Plan we developed methodology to estimate potential load and delivered load for crops (field crops + rice), animal production, rural living and from atmospheric N input. We use scenarios to allow for uncertainty in delivery to estimate the relative roles of different rural forms of pollution. Livestock raising is the major source of NPS pollution. Despite a 75% rural population, rural living contributes almost nothing to surface water pollution. While over-fertilization is typical, nutrient runoff from crops is low. Our results have implications for policies now under development for NPS control in China. - Highlights: ► Provides specific methods guidance for agricultural NPS assessment in China. ► Crops do not contribute significant N and P to watercourses in North China Plain. ► Rural living contributes almost no N and P to watercourses. ► Livestock is the only significant agricultural source of COD, N and P. - We address the methodology for agricultural NPS pollution assessment. We show that livestock, not rural living or crops, is the significant pollutant source.

Effect of PEG biofunctional spacers and TAT peptide on dsRNA loading on gold nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Sanz, Vanesa; Conde, Joao; Hernandez, Yulan [Universidad de Zaragoza, Instituto de Nanociencia de Aragon (Spain); Baptista, Pedro V. [Universidade Nova de Lisboa, Departamento de Ciencias da Vida, Faculdade de Ciencias e Tecnologia, Centro de Investigacao em Genetica Molecular Humana (Portugal); Ibarra, M. R.; Fuente, Jesus M. de la, E-mail: jmfuente@unizar.es [Universidad de Zaragoza, Instituto de Nanociencia de Aragon (Spain)

2012-06-15

The surface chemistry of gold nanoparticles (AuNPs) plays a critical role in the self-assembly of thiolated molecules and in retaining the biological function of the conjugated biomolecules. According to the well-established gold-thiol interaction the undefined ionic species on citrate-reduced gold nanoparticle surface can be replaced with a self-assembled monolayer of certain thiolate derivatives and other biomolecules. Understanding the effect of such derivatives in the functionalization of several types of biomolecules, such as PEGs, peptides or nucleic acids, has become a significant challenge. Here, an approach to attach specific biomolecules to the AuNPs ({approx}14 nm) surface is presented together with a study of their effect in the functionalization with other specific derivatives. The effect of biofunctional spacers such as thiolated poly(ethylene glycol) (PEG) chains and a positive peptide, TAT, in dsRNA loading on AuNPs is reported. Based on the obtained data, we hypothesize that loading of oligonucleotides onto the AuNP surface may be controlled by ionic and weak interactions positioning the entry of the oligo through the PEG layer. We demonstrate that there is a synergistic effect of the TAT peptide and PEG chains with specific functional groups on the enhancement of dsRNA loading onto AuNPs.

Effect of PEG biofunctional spacers and TAT peptide on dsRNA loading on gold nanoparticles

International Nuclear Information System (INIS)

Sanz, Vanesa; Conde, João; Hernández, Yulán; Baptista, Pedro V.; Ibarra, M. R.; Fuente, Jesús M. de la

2012-01-01

The surface chemistry of gold nanoparticles (AuNPs) plays a critical role in the self-assembly of thiolated molecules and in retaining the biological function of the conjugated biomolecules. According to the well-established gold–thiol interaction the undefined ionic species on citrate-reduced gold nanoparticle surface can be replaced with a self-assembled monolayer of certain thiolate derivatives and other biomolecules. Understanding the effect of such derivatives in the functionalization of several types of biomolecules, such as PEGs, peptides or nucleic acids, has become a significant challenge. Here, an approach to attach specific biomolecules to the AuNPs (∼14 nm) surface is presented together with a study of their effect in the functionalization with other specific derivatives. The effect of biofunctional spacers such as thiolated poly(ethylene glycol) (PEG) chains and a positive peptide, TAT, in dsRNA loading on AuNPs is reported. Based on the obtained data, we hypothesize that loading of oligonucleotides onto the AuNP surface may be controlled by ionic and weak interactions positioning the entry of the oligo through the PEG layer. We demonstrate that there is a synergistic effect of the TAT peptide and PEG chains with specific functional groups on the enhancement of dsRNA loading onto AuNPs.

Preparation and in vitro characterization of gallic acid-loaded human serum albumin nanoparticles

Science.gov (United States)

Mohammad-Beigi, Hossein; Shojaosadati, Seyed Abbas; Morshedi, Dina; Arpanaei, Ayyoob; Marvian, Amir Tayaranian

2015-04-01

Gallic acid (GA), as an antioxidant and antiparkinson agent, was loaded onto cationic human serum albumin nanoparticles (HSA NPs). Polyethylenimine (PEI)-coated HSA (PEI-HSA) NPs were prepared using three different methods: (I) coating negatively charged HSA NPs with positively charged PEI through attractive electrostatic interactions, (II) coating HSA NPs with PEI via covalent amide bond formation using N-(3-dimethylaminopropyl)- N-ethylcarbodiimide hydrochloride, and (III) coating HSA NPs with PEI via covalent bonding using glutaraldehyde for linking amine groups of PEI and amine groups of albumin NPs. Method II was selected since it resulted in a higher shift in the zeta potential value (mV) and less zeta potential value deviation, and also less size polydispersity. GA was loaded by adsorption onto the surface of PEI-HSA NPs of two different sizes: 117 ± 2.9 nm (PEI-P1) and 180 ± 3.1 nm (PEI-P2) NPs. Both GA-entrapment and GA-loading efficiencies increased slightly with the increasing size of NPs, and were affected intensely by the mass ratio of GA to PEI-HSA NPs. Free radical scavenging of GA was quantified based on the 2,2-diphenyl-1-picrylhydrazyl method. The obtained results showed that GA remains active during the preparation of GA-loaded PEI-HSA NPs. The cytotoxicities of HSA, PEI-HSA, and GA-loaded PEI-HSA NPs on the PC-12 cells, as the neuroendocrine cell line, were measured. Our results indicate that positively charged PEI-HSA NPs are good candidates for efficient and safe delivery of GA to the brain.

Potassium hydroxide: an alternative reagent to perform the modified apt test.

Science.gov (United States)

Chicaiza, Henry; Hellstrand, Karl; Lerer, Trudy; Smith, Sharon; Sylvester, Francisco

2014-09-01

We tested the performance of potassium hydroxide (KOH) in the modified Apt test under different experimental conditions using sodium hydroxide as a positive control. Like sodium hydroxide, KOH differentiated fresh fetal and adult blood stains on a cloth but not dried blood. KOH may be used to perform the Apt test at the bedside. Copyright © 2014 Elsevier Inc. All rights reserved.

Technical memorandum: instrumentation for APT and LTPP

CSIR Research Space (South Africa)

Steyn, WJvdM

2006-01-01

Full Text Available . In these phases, the parameters to be monitored on APT and LTPP sections have been identified, appropriate instruments and sensors for monitoring these parameters have been identified, and recommendations made regarding new developments, required upgrading...

The Dynamic Environment of Crypto Markets: The Lifespan of New Psychoactive Substances (NPS and Vendors Selling NPS

Directory of Open Access Journals (Sweden)

Elle Wadsworth

2018-03-01

Full Text Available The Internet has played a major role in the distribution of New Psychoactive Substances (NPS, and crypto markets are increasingly used for the anonymous sale of drugs, including NPS. This study explores the availability of individual NPS and vendors on the crypto markets and considers whether crypto markets are a reliable platform for the sale of NPS. Data was collected from 22 crypto markets that were accessed through the hidden web using the Onion Router (Tor. Data collection took place bimonthly from October 2015 to October 2016 as part of the CASSANDRA (Computer Assisted Solutions for Studying the Availability aNd DistRibution of novel psychoActive substances project. In seven snapshots over 12 months, 808 unique vendors were found selling 256 unique NPS. The total number of individual NPS and vendors increased across the data collection period (increase of 93.6% and 71.6%, respectively. Only 24% (n = 61 of the total number of NPS and 4% (n = 31 of vendors appeared in every snapshot over the 12 months, whereas 21% (n = 54 of NPS and 45% (n = 365 of vendors only appeared once throughout the data collection. The individual NPS and vendors did not remain the same over the 12 months. However, the availability of NPS and vendors selling NPS grew. NPS consistently available on crypto markets could indicate popular substances.

APT and CEST Techniques for Clinical MRI

NARCIS (Netherlands)

Keupp, J.

2011-01-01

Chemical exchange saturation transfer (CEST) based in vivo detectionand quantification of endogenous macro-molecules (i.e., amide proton transfer, APT) or exogenous contrast agents is a highly sensitivemolecular MRI technique bearing a substantial clinical potential forexample in oncology or for

Superconducting cavities for the APT accelerator

International Nuclear Information System (INIS)

Krawczyk, F.L.; Gentzlinger, R.C.; Haynes, B.; Montoya, D.I.; Rusnak, B.; Shapiro, A.H.

1997-01-01

The design of an Accelerator Production of Tritium (APT) facility being investigated at Los Alamos includes a linear accelerator using superconducting rf-cavities for the acceleration of a high-current cw proton beam. For electron accelerators with particles moving at the speed of light (β ∼ 1.0), resonators with a rounded shape, consisting of ellipsoidal and cylindrical sections, are well established. They are referred to as elliptical cavities. For the APT-design, this shape has been adapted for much slower proton beams with β ranging from 0.60 to 0.94. This is a new energy range, in which resonators of an elliptical type have never been used before. Simulations with the well-proven electromagnetic modeling tools MAFIA and SUPERFISH were performed. The structures have been optimized for their rf and mechanical properties as well as for beam dynamics requirements. The TRAK-RF simulation code is used to investigate potential multipacting in these structures. All the simulations will be put to a final test in experiments performed on single cell cavities that have started in the structures laboratory

The Dynamic Environment of Crypto Markets: The Lifespan of New Psychoactive Substances (NPS) and Vendors Selling NPS.

Science.gov (United States)

Wadsworth, Elle; Drummond, Colin; Deluca, Paolo

2018-03-16

The Internet has played a major role in the distribution of New Psychoactive Substances (NPS), and crypto markets are increasingly used for the anonymous sale of drugs, including NPS. This study explores the availability of individual NPS and vendors on the crypto markets and considers whether crypto markets are a reliable platform for the sale of NPS. Data was collected from 22 crypto markets that were accessed through the hidden web using the Onion Router (Tor). Data collection took place bimonthly from October 2015 to October 2016 as part of the CASSANDRA ( C omputer A ssisted S olutions for S tudying the A vailability a N d D ist R ibution of novel psycho A ctive substances) project. In seven snapshots over 12 months, 808 unique vendors were found selling 256 unique NPS. The total number of individual NPS and vendors increased across the data collection period (increase of 93.6% and 71.6%, respectively). Only 24% ( n = 61) of the total number of NPS and 4% ( n = 31) of vendors appeared in every snapshot over the 12 months, whereas 21% ( n = 54) of NPS and 45% ( n = 365) of vendors only appeared once throughout the data collection. The individual NPS and vendors did not remain the same over the 12 months. However, the availability of NPS and vendors selling NPS grew. NPS consistently available on crypto markets could indicate popular substances.

Transferrin-Modified Nanoparticles for Photodynamic Therapy Enhance the Antitumor Efficacy of Hypocrellin A

Directory of Open Access Journals (Sweden)

Xi Lin

2017-11-01

Full Text Available Photodynamic therapy (PDT has emerged as a potent novel therapeutic modality that induces cell death through light-induced activation of photosensitizer. But some photosensitizers have characteristics of poor water-solubility and non-specific tissue distribution. These characteristics become main obstacles of PDT. In this paper, we synthesized a targeting drug delivery system (TDDS to improve the water-solubility of photosensitizer and enhance the ability of targeted TFR positive tumor cells. TDDS is a transferrin-modified Poly(D,L-Lactide-co-glycolide (PLGA and carboxymethyl chitosan (CMC nanoparticle loaded with a photosensitizer hypocrellin A (HA, named TF-HA-CMC-PLGA NPs. Morphology, size distribution, Fourier transform infrared (FT-IR spectra, encapsulation efficiency, and loading capacity of TF-HA-CMC-PLGA NPs were characterized. In vitro TF-HA-CMC-PLGA NPs presented weak dark cytotoxicity and significant photo-cytotoxicity with strong reactive oxygen species (ROS generation and apoptotic cancer cell death. In vivo photodynamic antitumor efficacy of TF-HA-CMC-PLGA NPs was investigated with an A549 (TFR positive tumor-bearing model in male athymic nude mice. TF-HA-CMC-PLGA NPs caused tumor delay with a remarkable tumor inhibition rate of 63% for 15 days. Extensive cell apoptosis in tumor tissue and slight side effects in normal organs were observed. The results indicated that TDDS has great potential to enhance PDT therapeutic efficacy.

Preparation and in vitro characterization of gallic acid-loaded human serum albumin nanoparticles

International Nuclear Information System (INIS)

Mohammad-Beigi, Hossein; Shojaosadati, Seyed Abbas; Morshedi, Dina; Arpanaei, Ayyoob; Marvian, Amir Tayaranian

2015-01-01

Gallic acid (GA), as an antioxidant and antiparkinson agent, was loaded onto cationic human serum albumin nanoparticles (HSA NPs). Polyethylenimine (PEI)-coated HSA (PEI-HSA) NPs were prepared using three different methods: (I) coating negatively charged HSA NPs with positively charged PEI through attractive electrostatic interactions, (II) coating HSA NPs with PEI via covalent amide bond formation using N-(3-dimethylaminopropyl)-N-ethylcarbodiimide hydrochloride, and (III) coating HSA NPs with PEI via covalent bonding using glutaraldehyde for linking amine groups of PEI and amine groups of albumin NPs. Method II was selected since it resulted in a higher shift in the zeta potential value (mV) and less zeta potential value deviation, and also less size polydispersity. GA was loaded by adsorption onto the surface of PEI-HSA NPs of two different sizes: 117 ± 2.9 nm (PEI-P1) and 180 ± 3.1 nm (PEI-P2) NPs. Both GA-entrapment and GA-loading efficiencies increased slightly with the increasing size of NPs, and were affected intensely by the mass ratio of GA to PEI-HSA NPs. Free radical scavenging of GA was quantified based on the 2,2-diphenyl-1-picrylhydrazyl method. The obtained results showed that GA remains active during the preparation of GA-loaded PEI-HSA NPs. The cytotoxicities of HSA, PEI-HSA, and GA-loaded PEI-HSA NPs on the PC-12 cells, as the neuroendocrine cell line, were measured. Our results indicate that positively charged PEI-HSA NPs are good candidates for efficient and safe delivery of GA to the brain

Preparation and in vitro characterization of gallic acid-loaded human serum albumin nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Mohammad-Beigi, Hossein; Shojaosadati, Seyed Abbas, E-mail: shoja-sa@modares.ac.ir [Tarbiat Modares University, Biotechnology Group, Faculty of Chemical Engineering (Iran, Islamic Republic of); Morshedi, Dina; Arpanaei, Ayyoob [National Institute of Genetic Engineering and Biotechnology, Department of Industrial and Environmental Biotechnology (Iran, Islamic Republic of); Marvian, Amir Tayaranian [Aarhus University, Department of Biomedicine (Denmark)

2015-04-15

Gallic acid (GA), as an antioxidant and antiparkinson agent, was loaded onto cationic human serum albumin nanoparticles (HSA NPs). Polyethylenimine (PEI)-coated HSA (PEI-HSA) NPs were prepared using three different methods: (I) coating negatively charged HSA NPs with positively charged PEI through attractive electrostatic interactions, (II) coating HSA NPs with PEI via covalent amide bond formation using N-(3-dimethylaminopropyl)-N-ethylcarbodiimide hydrochloride, and (III) coating HSA NPs with PEI via covalent bonding using glutaraldehyde for linking amine groups of PEI and amine groups of albumin NPs. Method II was selected since it resulted in a higher shift in the zeta potential value (mV) and less zeta potential value deviation, and also less size polydispersity. GA was loaded by adsorption onto the surface of PEI-HSA NPs of two different sizes: 117 ± 2.9 nm (PEI-P1) and 180 ± 3.1 nm (PEI-P2) NPs. Both GA-entrapment and GA-loading efficiencies increased slightly with the increasing size of NPs, and were affected intensely by the mass ratio of GA to PEI-HSA NPs. Free radical scavenging of GA was quantified based on the 2,2-diphenyl-1-picrylhydrazyl method. The obtained results showed that GA remains active during the preparation of GA-loaded PEI-HSA NPs. The cytotoxicities of HSA, PEI-HSA, and GA-loaded PEI-HSA NPs on the PC-12 cells, as the neuroendocrine cell line, were measured. Our results indicate that positively charged PEI-HSA NPs are good candidates for efficient and safe delivery of GA to the brain.

A perspective of mitochondrial dysfunction in rats treated with silver and titanium nanoparticles (AgNPs and TiNPs).

Science.gov (United States)

Pereira, Lilian Cristina; Pazin, Murilo; Franco-Bernardes, Mariana Furio; Martins, Airton da Cunha; Barcelos, Gustavo Rafael Mazzaron; Pereira, Márcio Cesar; Mesquita, João Paulo; Rodrigues, Jairo Lisboa; Barbosa, Fernando; Dorta, Daniel Junqueira

2018-05-01

Nanotechnology is a growing branch of science that deals with the development of structural features bearing at least one dimension in the nano range. More specifically, nanomaterials are defined as objects with dimensions that range from 1 to 100 nm, which give rise to interesting properties. In particular, silver and titanium nanoparticles (AgNPs and TiNPs, respectively) are known for their biological and biomedical properties and are often used in consumer products such as cosmetics, food additives, kitchen utensils, and toys. This situation has increased environmental and occupational exposure to AgNPs and TiNPs, which has placed demand for the risk assessment of NPs. Indeed, the same properties that make nanomaterials so attractive could also prove deleterious to biological systems. Of particular concern is the effect of NPs on mitochondria because these organelles play an essential role in cellular homeostasis. In this scenario, this work aimed to study how AgNPs and TiNPs interact with the mitochondrial respiration chain and to analyze how this interaction interferes in the bioenergetics and oxidative state of the organelles after sub-chronic exposure. Mitochondria were exposed to the NPs by gavage treatment for 21 days to check whether co-exposure of the organelles to the two types of NPs elicited any mitochondrion-NP interaction. More specifically, male Wistar rats were randomly assigned to four groups. Groups I, II, III, and IV received mineral oil, TiNPs (100 μg/kg/day), AgNPs (100 μg/kg/day), and TiNPs + AgNPs (100 μg/kg/day), respectively, by gavage. The liver was immediately removed, and the mitochondria were isolated and used within 3 h. Exposure of mitochondria to TiNPs + AgNPs lowered the respiratory control ratio, causing an uncoupling effect in the oxidative phosphorylation system. Moreover, both types of NPs induced mitochondrial swelling. Extended exposure of mitochondria to the NPs maintained increased ROS levels and

Miniaturization of the atmospheric laser communication APT system

Science.gov (United States)

Sun, Wei; Ai, Yong; Yang, Jinling; Huang, Haibo

2003-09-01

The paper presents a scheme of the miniaturization of APT system and the design of the system based on the investigation of status in quo. It deals with the infrared image of the other terminal's beacon from the Charge Coupled Device (CCD) by the Complex Programmable Logic Device (CPLD). The result of the transaction is delivered to Single Chip Microcomputer (SCM), which controls the micro-servomotor. Subsequently, the precision drive system drives the optical system that uses only one light axis for signal beam and beacon to finish the acquisition, pointing, and tracking of the communication terminals. The anlayses of the APT system's error indicate that the tracking error limits in 70uRad with the weight of the system lighter than 8-kilogram.

Development of silver nanoparticles loaded chitosan-alginate constructs with biomedical potentialities.

Science.gov (United States)

Bilal, Muhammad; Rasheed, Tahir; Iqbal, Hafiz M N; Li, Chuanlong; Hu, Hongbo; Zhang, Xuehong

2017-12-01

Herein, a facile biosynthesis of silver nanoparticles (AgNPs) and AgNPs-loaded chitosan-alginate constructs with biomedical potentialities is reported. The UV-vis spectroscopic profile confirmed the synthesis of AgNPs using methanolic leaves extract of Euphorbia helioscopia. The newly developed AgNPs were characterized using various analytical and imaging techniques including UV-vis and FT-IR spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), atomic force microscopy (AFM), and transmission electron microscopy (TEM). The optimally yielded AgNPs at 24h reaction period were loaded onto various chitosan-alginate constructs. A maximum of 95% loading efficiency (LE) was recorded with a chitosan: alginate ratio at 2:1, followed by 81% at 2:2 ratios. The anti-bacterial activities of AgNPs and AgNPs loaded chitosan-alginate constructs were tested against six bacterial strains i.e. Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Acinetobacter baumannii, Morganella morganii and Haemophilus influenza. A significant reduction in the log values was recorded for all test constructs, in comparison to the initial bacterial count (control value, i.e., 1.5×10 8 CFU/mL). The cytotoxicity profile revealed complete biocompatibility against normal cell line i.e. L929. Almost all constructs showed considerable cytotoxicity up to certain extant against human epithelial cells (HeLa) cancer cells. In summary, the highest antibacterial activities along with anti-cancer behavior both suggest the biomedical potentialities of newly engineered AgNPs and AgNPs-loaded chitosan-alginate constructs. Copyright © 2017 Elsevier B.V. All rights reserved.

Antimicrobial and anticancer activity of AgNPs coated with Alphonsea sclerocarpa extract.

Science.gov (United States)

Doddapaneni, Suman Joshi D S; Amgoth, Chander; Kalle, Arunasree M; Suryadevara, Surya Narayana; Alapati, Krishna Satya

2018-03-01

The synthesis and characterization of an aggregate of AgNPs coated with plant extract (PE) from Alphonsea sclerocarpa and its significant antimicrobial activity and inhibition on K562 (blood cancer) cells have been appended in the article. Synthesis of aggregate [(AgNPs)-(PE)] has been followed by a facile eco-friendly approach without using any harmful chemicals. The morphology of an aggregate [(AgNPs)-(PE)] was confirmed by TEM and SEM microscopic characterizations. Properties like solid state, the presence of functional groups, and elemental composition have been characterized through the XRD, FTIR, and EDAX. The biocompatibility of synthesized aggregate of [(AgNPs)-(PE)] was confirmed by the MTT assay. An in vitro cell (HEK293)-based studies were performed for the biocompatibility tests and it is found that the aggregate [(AgNPs)-(PE)] is not harmful to normal/healthy cells. Even though A. sclerocarpa show the antimicrobial (antibacterial and antifungal) activity, it has been further enhanced with the developed aggregate of [(AgNPs)-(PE)]. Furthermore, it has been extended to examine the cellular inhibition on K562 cells and obtained > 75% cell inhibition for 24 h treated cells.

Enhanced photocatalytic performance of sandwiched ZnO@Ag@Cu2O nanorod films: the distinct role of Ag NPs in the visible light and UV region

International Nuclear Information System (INIS)

Ren, Shoutian; Wang, Yingying; Wang, Benyang; Wang, Qiang; Zhao, Guoliang

2015-01-01

Sandwiched ZnO@Ag@Cu 2 O nanorod films were synthesized by successive electrodeposition, magnetron sputtering and the second electrodeposition. The as-synthesized composites were characterized by x-ray diffraction patterns, field emission scanning electron microscopy, low- and high-resolution transmission electron microscopy and a UV–vis spectrophotometer. Their photocatalytic performance was estimated by the degradation of a methyl orange solution under UV or visible-light irradiation, respectively. In the visible region, due to localized surface plasmon resonance absorption of Ag NPs, ZnO@Ag@Cu 2 O showed a significantly enhanced photocatalytic performance. The enhancement factor of Ag NPs on the catalytic performance of ZnO@Ag@Cu 2 O was estimated as a function of the Cu 2 O deposition time, and the corresponding enhancement mechanism was also evaluated by the monochromatic photocatalytic experiment and discrete dipole approximation simulation. In the UV region, due to the formation of a Schottky junction (e.g. Ag/ZnO, Ag/Cu 2 O), a limited enhanced photocatalytic performance was also realized for ZnO@Ag@Cu 2 O photocatalysts. (paper)

Preparation of curcumin-loaded pluronic F127/chitosan nanoparticles for cancer therapy

International Nuclear Information System (INIS)

Phuc Le, Thi Minh; Pham, Van Phuc; Lua Dang, Thi Minh; Huyen La, Thi; Le, Thi Hanh; Le, Quang Huan

2013-01-01

Nanoparticles (NPs) have been proven to be an effective delivery system with few side effects for anticancer drugs. In this study, curcumin-loaded NPs have been prepared by an ionic gelation method using chitosan (Chi) and pluronic ® F-127 (PF) as carriers to deliver curcumin to the target cancer cells. Prepared NPs were characterized using Zetasizer, fluorescence microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Our results showed that the encapsulation efficiency of curcumin was approximately 50%. The average size of curcumin-loaded PF/Chi NPs was 150.9 nm, while the zeta potential was 5.09 mV. Cellular uptake of curcumin-loaded NPs into HEK293 cells was confirmed by fluorescence microscopy. (paper)

Medical Isotope Production With The Accelerator Production of Tritium (APT) Facility

International Nuclear Information System (INIS)

Buckner, M.; Cappiello, M.; Pitcher, E.; O'Brien, H.

1998-01-01

In order to meet US tritium needs to maintain the nuclear weapons deterrent, the Department of Energy (DOE) is pursuing a dual track program to provide a new tritium source. A record of decision is planned for late in 1998 to select either the Accelerator Production of Tritium (APT) or the Commercial Light Water Reactor (CLWR) as the technology for new tritium production in the next century. To support this decision, an APT Project was undertaken to develop an accelerator design capable of producing 3 kg of tritium per year by 2007 (START I requirements). The Los Alamos National Laboratory (LANL) was selected to lead this effort with Burns and Roe Enterprises, Inc. (BREI) / General Atomics (GA) as the prime contractor for design, construction, and commissioning of the facility. If chosen in the downselect, the facility will be built at the Savannah River Site (SRS) and operated by the SRS Maintenance and Operations (M ampersand O) contractor, the Westinghouse Savannah River Company (WSRC), with long-term technology support from LANL. These three organizations (LANL, BREI/GA, and WSRC) are working together under the direction of the APT National Project Office which reports directly to the DOE Office of Accelerator Production which has program authority and responsibility for the APT Project

High-performance SERS substrate based on hybrid structure of graphene oxide/AgNPs/Cu film@pyramid Si

Science.gov (United States)

Li, Zhe; Xu, Shi Cai; Zhang, Chao; Liu, Xiao Yun; Gao, Sai Sai; Hu, Li Tao; Guo, Jia; Ma, Yong; Jiang, Shou Zhen; Si, Hai Peng

2016-12-01

We present a novel surface-enhanced Raman scattering (SERS) substrate based on graphene oxide/silver nanoparticles/copper film covered silicon pyramid arrays (GO/AgNPs/PCu@Si) by a low-cost and simple method. The GO/AgNPs/PCu@Si substrate presents high sensitivity, good homogeneity and well stability with R6G molecules as a probe. The detected concentration of Rhodamine 6 G (R6G) is as low as 10-15 M. These sensitive SERS behaviors are also confirmed in theory via a commercial COMSOL software, the electric field enhancement is not only formed between the AgNPs, but also formed between the AgNPs and Cu film. And the GO/AgNPs/PCu@Si substrates also present good property on practical application for the detection of methylene blue (MB) and crystal violet (CV). This work may offer a novel and practical method to facilitate the SERS applications in areas of medicine, food safety and biotechnology.

A Bottom-Up Assessment of Navy Flagship Schools: The NPS Faculty Critique of CNA's Report

National Research Council Canada - National Science Library

Gates, William

1998-01-01

... different than their undergraduate major, and higher course-loads. Cost analyses incorporating these benefits indicate that NPS is highly efficient at providing graduate education to naval officers at a low cost per student...

Molecular layer deposition of APTES on silicon nanowire biosensors: Surface characterization, stability and pH response

International Nuclear Information System (INIS)

Liang, Yuchen; Huang, Jie; Zang, Pengyuan; Kim, Jiyoung; Hu, Walter

2014-01-01

Graphical abstract: - Abstract: We report the use of molecular layer deposition (MLD) for depositing 3-aminopropyltriethoxysilane (APTES) on a silicon dioxide surface. The APTES monolayer was characterized using spectroscopic ellipsometry, contact angle goniometry, and atomic force microscopy. Effects of reaction time of repeating pulses and simultaneous feeding of water vapor with APTES were tested. The results indicate that the synergistic effects of water vapor and reaction time are significant for the formation of a stable monolayer. Additionally, increasing the number of repeating pulses improved the APTES surface coverage but led to saturation after 10 pulses. In comparing MLD with solution-phase deposition, the APTES surface coverage and the surface quality were nearly equivalent. The hydrolytic stability of the resulting films was also studied. The results confirmed that the hydrolysis process was necessary for MLD to obtain stable surface chemistry. Furthermore, we compared the pH sensing results of Si nanowire field effect transistors (Si NWFETs) modified by both the MLD and solution methods. The highly repeatable pH sensing results reflected the stability of APTES monolayers. The results also showed an improved pH response of the sensor prepared by MLD compared to the one prepared by the solution treatment, which indicated higher surface coverage of APTES

Molecular layer deposition of APTES on silicon nanowire biosensors: Surface characterization, stability and pH response

Science.gov (United States)

Liang, Yuchen; Huang, Jie; Zang, Pengyuan; Kim, Jiyoung; Hu, Walter

2014-12-01

We report the use of molecular layer deposition (MLD) for depositing 3-aminopropyltriethoxysilane (APTES) on a silicon dioxide surface. The APTES monolayer was characterized using spectroscopic ellipsometry, contact angle goniometry, and atomic force microscopy. Effects of reaction time of repeating pulses and simultaneous feeding of water vapor with APTES were tested. The results indicate that the synergistic effects of water vapor and reaction time are significant for the formation of a stable monolayer. Additionally, increasing the number of repeating pulses improved the APTES surface coverage but led to saturation after 10 pulses. In comparing MLD with solution-phase deposition, the APTES surface coverage and the surface quality were nearly equivalent. The hydrolytic stability of the resulting films was also studied. The results confirmed that the hydrolysis process was necessary for MLD to obtain stable surface chemistry. Furthermore, we compared the pH sensing results of Si nanowire field effect transistors (Si NWFETs) modified by both the MLD and solution methods. The highly repeatable pH sensing results reflected the stability of APTES monolayers. The results also showed an improved pH response of the sensor prepared by MLD compared to the one prepared by the solution treatment, which indicated higher surface coverage of APTES.

Preparation of anastrozole loaded PEG-PLA nanoparticles: evaluation of apoptotic response of breast cancer cell lines.

Science.gov (United States)

Alyafee, Yusra A; Alaamery, Manal; Bawazeer, Shahad; Almutairi, Mansour S; Alghamdi, Badr; Alomran, Nawaf; Sheereen, Atia; Daghestani, Maha; Massadeh, Salam

2018-01-01

Anastrozole (ANS) is an aromatase inhibitor that is widely used as a treatment for breast cancer in postmenopausal women. Despite the wide use of ANS, it is associated with serious side effects due to uncontrolled delivery. In addition, ANS exhibits low solubility and short plasma half-life. Nanotechnology-based drug delivery has the potential to enhance the efficacy of drugs and overcome undesirable side effects. In this study, we aimed to prepare novel ANS-loaded PLA-PEG-PLA nanoparticles (ANS-NPs) and to compare the apoptotic response of MCF-7 cell line to both ANS and ANS-loaded NPs. ANS-NPs were synthesized using double emulsion method and characterized using different methods. The apoptotic response was evaluated by assessing cell viability, morphology, and studying changes in the expression of MAPK3 , MCL1 , and c-MYC apoptotic genes in MCF-7 cell lines. ANS was successfully encapsulated within PLA-PEG-PLA, forming monodisperse therapeutic NPs with an encapsulation efficiency of 67%, particle size of 186±27.13, and a polydispersity index of 0.26±0.11 with a sustained release profile extended over 144 hours. In addition, results for cell viability and for gene expression represent a similar apoptotic response between the free ANS and ANS-NPs. The synthesized ANS-NPs showed a similar therapeutic effect as the free ANS, which provides a rationale to pursue pre-clinical evaluation of ANS-NPs on animal models.

Biomedical applications of SPION@APTES@PEG-folic acid@carboxylated quercetin nanodrug on various cancer cells

International Nuclear Information System (INIS)

Akal, Z.Ü.; Alpsoy, L.; Baykal, A.

2016-01-01

Highlights: • SPION has been synthesized via Reflux synthesis route. • SPION@APTES@FA-PEG@CQ nanodrug has super paramagnetic property. • SPION@APTES@FA-PEG@CQ nanodrug has cytotoxic, apoptotic and necrotic effects on HeLa and MCF-7 cells. • SPION@APTES@FA-PEG@CQ nanodrug can be potentially used for the delivery of quercetin to cervical and breast cancer cells. - Abstract: In this study, carboxylated quercetin (CQ) was conjugated to superparamagnetic iron oxide nanoparticles (SPIONs) which were modified by (3-aminopropyl) triethoxysilane (APTES), Folic acid (FA) and carboxylated Polyethylene glycol (PEG); (SPION@APTES@FA-PEG@CQ), nanodrug has been synthesized via polyol and accompanying by various chemical synthesis routes. The characterization of the final product was done via X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Thermal gravimetric analysis (TGA), Transmission electron spectroscopy (TEM) and Vibrating sample magnetometer (VSM). Its cytotoxic and apoptotic activities on over expressed folic acid receptor (FR + ) (MCF-7, HeLa) and none expressed folic acid receptor (FR-) (A549) cancer cell lines were determined by using MTT assay, Real-Time Cell Analysis, TUNEL assay, Annexin assay and RT-PCR analysis for Caspase3/7 respectively. SPION@APTES@FA-PEG@CQ nanodrug showed higher cytotoxicity against HeLa and MCF-7 cell lines as compared with A549 cell line. Moreover, SPION@APTES@FA-PEG@CQ nanodrug also caused higher apoptotic and necrotic effects in 100 μg/mL HeLa and MCF-7 cells than A549 cells. The findings showed that SPION@APTES@FA-PEG@CQ nanodrug has cytotoxic, apoptotic and necrotic effects on HeLa and MCF-7 which are FR over expressed cell lines and can be potentially used for the delivery of quercetin to cervical and breast cancer cells.

Biomedical applications of SPION@APTES@PEG-folic acid@carboxylated quercetin nanodrug on various cancer cells

Energy Technology Data Exchange (ETDEWEB)

Akal, Z.Ü., E-mail: zulker@fatih.edu.tr [Department of Biology, 34500 Büyükçekmece, Istanbul (Turkey); Alpsoy, L. [Department of Biology, 34500 Büyükçekmece, Istanbul (Turkey); Department of Medical Biology, 34500 Büyükçekmece, Istanbul (Turkey); Baykal, A. [Department of Chemistry, Fatih University, 34500 Büyükçekmece, Istanbul (Turkey)

2016-08-15

Highlights: • SPION has been synthesized via Reflux synthesis route. • SPION@APTES@FA-PEG@CQ nanodrug has super paramagnetic property. • SPION@APTES@FA-PEG@CQ nanodrug has cytotoxic, apoptotic and necrotic effects on HeLa and MCF-7 cells. • SPION@APTES@FA-PEG@CQ nanodrug can be potentially used for the delivery of quercetin to cervical and breast cancer cells. - Abstract: In this study, carboxylated quercetin (CQ) was conjugated to superparamagnetic iron oxide nanoparticles (SPIONs) which were modified by (3-aminopropyl) triethoxysilane (APTES), Folic acid (FA) and carboxylated Polyethylene glycol (PEG); (SPION@APTES@FA-PEG@CQ), nanodrug has been synthesized via polyol and accompanying by various chemical synthesis routes. The characterization of the final product was done via X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Thermal gravimetric analysis (TGA), Transmission electron spectroscopy (TEM) and Vibrating sample magnetometer (VSM). Its cytotoxic and apoptotic activities on over expressed folic acid receptor (FR + ) (MCF-7, HeLa) and none expressed folic acid receptor (FR-) (A549) cancer cell lines were determined by using MTT assay, Real-Time Cell Analysis, TUNEL assay, Annexin assay and RT-PCR analysis for Caspase3/7 respectively. SPION@APTES@FA-PEG@CQ nanodrug showed higher cytotoxicity against HeLa and MCF-7 cell lines as compared with A549 cell line. Moreover, SPION@APTES@FA-PEG@CQ nanodrug also caused higher apoptotic and necrotic effects in 100 μg/mL HeLa and MCF-7 cells than A549 cells. The findings showed that SPION@APTES@FA-PEG@CQ nanodrug has cytotoxic, apoptotic and necrotic effects on HeLa and MCF-7 which are FR over expressed cell lines and can be potentially used for the delivery of quercetin to cervical and breast cancer cells.

The effect of cyclodextrin on both the agglomeration and the in vitro characteristics of drug loaded and targeted silica nanoparticles

Science.gov (United States)

Khattabi, Areen M.; Alqdeimat, Diala A.

2018-02-01

One of the problems in the use of nanoparticles (NPs) as carriers in drug delivery systems is their agglomeration which mainly appears due to their high surface energy. This results in formation of NPs with different sizes leading to differences in their distribution and bioavailability. The surface coating of NPs with certain compounds can be used to prevent or minimize this problem. In this study, the effect of cyclodextrin (CD) on the agglomeration state and hence on the in vitro characteristics of drug loaded and targeted silica NPs was investigated. A sample of NPs was loaded with anticancer agents, then modified with a long polymer, carboxymethyl-β-cyclodextrin (CM-β-CD) and folic acid (FA), respectively. Another sample was modified similarly but without CD. The surface modification was characterized using fourier transform infrared spectroscopy (FT-IR). The polydispersity (PD) was measured using dynamic light scattering (DLS) and was found to be smaller for CD modified NPs. The results of the in vitro drug release showed that the release rate from both samples exhibited similar pattern for the first 5 hours, however the rate was faster from CD modified NPs after 24 hours. The in vitro cell viability assay confirmed that CD modified NPs were about 30% more toxic to HeLa cells. These findings suggest that CD has a clear effect in minimizing the agglomeration of such modified silica NPs, accelerating their drug release rate and enhancing their targeting effect.

NPS and Online WOM

Science.gov (United States)

Raassens, Néomie

2017-01-01

The Net Promoter Score (NPS) is, according to Reichheld, the single most reliable indicator of company growth, and many companies use this recommendation-based technique for measuring customer loyalty. Despite its widespread adoption by many companies across multiple industries, the debate about NPS goes on. A major concern is that managers treat NPS as being equivalent across customers, which is often very misleading. By using a unique data set that combines customers’ promoter scores and online word-of-mouth (eWOM) behavior, this research studies how individual customers’ promoter scores are related to eWOM, including its relationship with the three categories of customers that are identified by the NPS paradigm (i.e., promoters, passives, and detractors). Based on a sample of 189 customers, their promoter scores and corresponding eWOM, the results show that there is a positive relationship between customers’ promoter scores and the valence of online messages. Further, while detractors and promoters are homogeneous with respect to the valence of the eWOM messages they spread, passives show message valence heterogeneity. Thus, although passives, the largest group of customers, have no weight in calculating the NPS, our results reveal that companies should flag passives for further attention and action. PMID:29046609

Preparation of curcumin-loaded PCL-PEG-PCL triblock copolymeric nanoparticles by a microchannel technology.

Science.gov (United States)

Guo, Fangyuan; Guo, Dingjia; Zhang, Wei; Yan, Qinying; Yang, Yan; Hong, Weiyong; Yang, Gensheng

2017-03-01

Biodegradable polymeric nanoparticles (NPs) have potential therapeutic applications; however, preparing NPs of a specific diameter and uniform size distribution is a challenge. In this work, we fabricated a microchannel system for the preparation of curcumin (Cur)-loaded NPs by the interfacial precipitation method, which rapidly and consistently generated stable NPs with a relatively smaller diameter, narrow size distribution, and higher drug-loading capacity and entrapment efficiency. Poly(ε-caprolactone)-poly(ethylene glycol)-poly (ε-caprolactone) triblock copolymers(PCEC) used as the carrier material was synthesized and characterized. Cur-loaded PCEC NPs had an average size of 167.2nm with a zeta potential of -29.23mV, and showed a loading capacity and drug entrapment efficiency of 15.28%±0.23% and 96.11%±0.13%, respectively. Meanwhile, the NPs demonstrated good biocompatibility and bioavailability, efficient cellular uptake, and long circulation time and a possible liver targeting effect in vivo. These results indicate that the Cur-loaded PCEC NPs can be used as drug carriers in controlled delivery systems and other biomedical applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Enhanced antimicrobial activities of silver-nanoparticle-decorated reduced graphene nanocomposites against oral pathogens

International Nuclear Information System (INIS)

Peng, Jian-min; Lin, Jia-cheng; Chen, Zhuo-yu; Wei, Meng-chao; Fu, Yuan-xiang; Lu, Shu-shen; Yu, Dong-sheng; Zhao, Wei

2017-01-01

As a means of capitalizing on the synergistic properties between reduced graphene nanosheets (R-GNs) and silver nanoparticles (AgNPs), an efficient and convenient chemical reduction method was used to prepare silver-nanoparticle-decorated reduced graphene nanocomposites (R-GNs/Ag). The products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Raman spectroscopy, which confirmed the loading of well-dispersed silver nanoparticles on reduced graphene sheets. Their antimicrobial activities against oral pathogens such as Candida albicans, Lactobacillus acidophilus, Streptococcus mutans, and Aggregatibacter actinomycetemcomitans were investigated by MIC determination, the counting of colony-forming units (CFU), agar diffusion tests, and growth curve observation. Compared with pure R-GNs and AgNPs, R-GNs/Ag composites exhibited enhanced antimicrobial properties owing to highly dispersed AgNPs on R-GNs. - Highlights: • This study synthesized R-GNs/Ag composites by a chemical reduction method. • AgNPs were successfully dispersed on reduced graphene nanosheets. • R-GNs/Ag composites showed enhanced antimicrobial activities against oral pathogens compared with plain AgNPs or R-GNs.

Enhanced antimicrobial activities of silver-nanoparticle-decorated reduced graphene nanocomposites against oral pathogens

Energy Technology Data Exchange (ETDEWEB)

Peng, Jian-min; Lin, Jia-cheng; Chen, Zhuo-yu; Wei, Meng-chao [Guanghua School of Stomatology, Hospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou 510055 (China); Fu, Yuan-xiang; Lu, Shu-shen [School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Yu, Dong-sheng, E-mail: yudsh@mail.sysu.edu.cn [Guanghua School of Stomatology, Hospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou 510055 (China); Zhao, Wei, E-mail: zhaowei3@mail.sysu.edu.cn [Guanghua School of Stomatology, Hospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou 510055 (China)

2017-02-01

As a means of capitalizing on the synergistic properties between reduced graphene nanosheets (R-GNs) and silver nanoparticles (AgNPs), an efficient and convenient chemical reduction method was used to prepare silver-nanoparticle-decorated reduced graphene nanocomposites (R-GNs/Ag). The products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Raman spectroscopy, which confirmed the loading of well-dispersed silver nanoparticles on reduced graphene sheets. Their antimicrobial activities against oral pathogens such as Candida albicans, Lactobacillus acidophilus, Streptococcus mutans, and Aggregatibacter actinomycetemcomitans were investigated by MIC determination, the counting of colony-forming units (CFU), agar diffusion tests, and growth curve observation. Compared with pure R-GNs and AgNPs, R-GNs/Ag composites exhibited enhanced antimicrobial properties owing to highly dispersed AgNPs on R-GNs. - Highlights: • This study synthesized R-GNs/Ag composites by a chemical reduction method. • AgNPs were successfully dispersed on reduced graphene nanosheets. • R-GNs/Ag composites showed enhanced antimicrobial activities against oral pathogens compared with plain AgNPs or R-GNs.

Enhanced Radiosensitization Effect of Curcumin Delivered by PVP-PCL Nanoparticle in Lung Cancer

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Cuixia Wen

2017-01-01

Full Text Available Curcumin, the principal polyphenolic curcuminoid, has been reported in numerous studies for its antitumor effect in a series of cancers. It is also reported that curcumin possesses radiosensitization effect in some cancers. However, the poor solubility and unsatisfied bioavailability of curcumin significantly undermine its potential application. Here we prepared curcumin loaded nanoparticles by employing PVP-PCL as drug carrier. Characterization studies indicated the satisfied drug loading efficiency and a sustained in vitro release pattern. Quantification uptake study showed that the uptake efficiency of Cum-NPs by lung cancer cells was time- and dose-dependent. In vitro anticancer study demonstrated the superior cytotoxic effect of Cum-NPs with stronger apoptotic induction over free Cum. Most importantly, there is almost no report on the radiosensitization effect of curcumin loaded nanoparticles. Here, Cum-NPs led to more inhibition of the colony forming ability of A549 cells as compared to the equivalent concentration of free Cum as shown in clonogenic assay. Furthermore, Cum-NPs are much more effective in enhancing the tumor growth inhibitory effect of radiation therapy in a A549 xenograft model. Therefore, results from the current study seem to be the first report on the radiosensitization effect of Cum-NPs and paved the way for a curcumin nanodrug delivery system as a potential radiation adjuvant.

The studies of PLGA nanoparticles loading atorvastatin calcium for oral administration in vitro and in vivo

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Zhenbao Li

2017-05-01

Full Text Available A biodegradable poly(lactic-co-glycolic acid loading atorvastatin calcium (AC nanoparticles (AC-PLGA-NPs were prepared by probe ultrasonication and evaporation method aiming at improving the oral bioavailability of AC. The effects of experimental parameters, including stabilizer species, stabilizer concentration and pH of aqueous phase, on particle size were also evaluated. The resultant nanoparticles were in spherical shape with an average diameter of 174.7 nm and a narrow particle size distribution. And the drug loading and encapsulation efficiency were about 8% and 71%, respectively. The particle size and polydispersion were almost unchanged in 10 days. The release curves of AC-PLGA-NPs in vitro displaying sustained release characteristics indicated that its release mechanisms were matrix erosion and diffusion. The pharmacokinetic study in vivo revealed that the Cmax and AUC0-∞ of AC-PLGA-NPs in rats were nearly 3.7-fold and 4.7-fold higher than that of pure atorvastatin calcium suspension. Our results demonstrated that the delivery of AC-PLGA-NPs could be a promising approach for the oral delivery of AC for enhanced bioavailability.

Preparation of finasteride capsules-loaded drug nanoparticles: formulation, optimization, in vitro, and pharmacokinetic evaluation

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Ahmed TA

2016-02-01

Full Text Available Tarek A Ahmed1,2 1Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia; 2Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Al-Azhar University, Cairo, Egypt Abstract: In this study, optimized freeze-dried finasteride nanoparticles (NPs were prepared from drug nanosuspension formulation that was developed using the bottom–up technique. The effects of four formulation and processing variables that affect the particle size and solubility enhancement of the NPs were explored using the response surface optimization design. The optimized formulation was morphologically characterized using transmission electron microscopy (TEM. Physicochemical interaction among the studied components was investigated. Crystalline change was investigated using X-ray powder diffraction (XRPD. Crystal growth of the freeze-dried NPs was compared to the corresponding aqueous drug nanosuspension. Freeze-dried NPs formulation was subsequently loaded into hard gelatin capsules that were examined for in vitro dissolution and pharmacokinetic behavior. Results revealed that in most of the studied variables, some of the quadratic and interaction effects had a significant effect on the studied responses. TEM image illustrated homogeneity and shape of the prepared NPs. No interaction among components was noticed. XRPD confirmed crystalline state change in the optimized NPs. An enhancement in the dissolution rate of more than 2.5 times from capsules filled with optimum drug NPs, when compared to capsules filled with pure drug, was obtained. Crystal growth, due to Ostwald ripening phenomenon and positive Gibbs free energy, was reduced following lyophilization of the nanosuspension formulation. Pharmacokinetic parameters from drug NPs were superior to that of pure drug and drug microparticles. In conclusion, freeze-dried NPs based on drug nanosuspension formulation is a successful

Real time imaging and infrared background scene analysis using the Naval Postgraduate School infrared search and target designation (NPS-IRSTD) system

Science.gov (United States)

Bernier, Jean D.

1991-09-01

The imaging in real time of infrared background scenes with the Naval Postgraduate School Infrared Search and Target Designation (NPS-IRSTD) System was achieved through extensive software developments in protected mode assembly language on an Intel 80386 33 MHz computer. The new software processes the 512 by 480 pixel images directly in the extended memory area of the computer where the DT-2861 frame grabber memory buffers are mapped. Direct interfacing, through a JDR-PR10 prototype card, between the frame grabber and the host computer AT bus enables each load of the frame grabber memory buffers to be effected under software control. The protected mode assembly language program can refresh the display of a six degree pseudo-color sector in the scanner rotation within the two second period of the scanner. A study of the imaging properties of the NPS-IRSTD is presented with preliminary work on image analysis and contrast enhancement of infrared background scenes.

Apt strain measurement technique for impulsive loading applications

International Nuclear Information System (INIS)

Nanda, Soumya Ranjan; Kulkarni, Vinayak; Sahoo, Niranjan

2017-01-01

The necessity of precise measurement of strain time history for impulsive loading applications has been addressed in the present investigation. Finite element modeling is initially carried out for a hemispherical test model and stress bar assembly to arrive at an appropriate location for strain measurement. In dynamic calibration experiments, strain measurements are performed using two wire and three wire quarter bride arrangements along with half bridge circuit. Usefulness of these arrangements has been verified by analyzing strain signals in time and frequency domains. Comparison of recovered force time histories proved that the half bridge circuit is the most suitable for such applications. Actual shock tube testing of the instrumented hemispherical test model confirmed the applicability of half bridge circuit for short duration strain measurements. (technical note)

Probing Interactions between AuNPs/AgNPs and Giant Unilamellar Vesicles (GUVs Using Hyperspectral Dark-field Microscopy

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Anupama Bhat

2018-03-01

Full Text Available Noble metallic nanoparticles (NPs such as gold and silver nanoparticles (AuNPs and AgNPs have been shown to exhibit anti-tumor effect in anti-angiogenesis, photothermal and radio therapeutics. On the other hand, cell membranes are critical locales for specific targeting of cancerous cells. Therefore, NP-membrane interactions need be studied at molecular level to help better understand the underlying physicochemical mechanisms for future applications in cancer nanotechnology. Herein, we report our study on the interactions between citrate stabilized colloidal AuNPs/AgNPs (10 nm in size and giant unilamellar vesicles (GUVs using hyperspectral dark-field microscopy. GUVs are large model vesicle systems well established for the study of membrane dynamics. GUVs used in this study were prepared with dimyristoyl phosphatidylcholine (DMPC and doped with cholesterol at various molar concentrations. Both imaging and spectral results support that AuNPs and AgNPs interact very differently with GUVs, i.e., AuNPs tend to integrate in between the lipid bilayer and form a uniform golden-brown crust on vesicles, whereas AgNPs are bejeweled on the vesicle surface as isolated particles or clusters with much varied configurations. The more disruptive capability of AuNPs is hypothesized to be responsible for the formation of golden brown crusts in AuNP-GUV interaction. GUVs of 20 mol% CHOL:DMPC were found to be a most economical concentration for GUVs to achieve the best integrity and the least permeability, consistent with the finding from other phase studies of lipid mixture that the liquid-ordered domains have the largest area fraction of the entire membrane at around 20 mol% of cholesterol.

Polymeric nanoparticles enhance the sonodynamic activity of meso-tetrakis (4-sulfonatophenyl) porphyrin in an in vitro neuroblastoma model

Science.gov (United States)

Canaparo, Roberto; Varchi, Greta; Ballestri, Marco; Foglietta, Federica; Sotgiu, Giovanna; Guerrini, Andrea; Francovich, Andrea; Civera, Pierluigi; Frairia, Roberto; Serpe, Loredana

2013-01-01

Purpose Sonodynamic therapy is a developing noninvasive modality for cancer treatment, based on the selective activation of a sonosensitizer agent by acoustic cavitation. The activated sonosensitizer agent might generate reactive oxygen species leading to cancer cell death. We investigated the potential poly-methyl methacrylate core-shell nanoparticles (NPs) loaded with meso-tetrakis (4-sulfonatophenyl) porphyrin (TPPS) have to function as an innovative sonosensitizing system, ie, TPPS-NPs. Methods Shockwaves (SWs) generated by a piezoelectric device were used to induce acoustic cavitation. The cytotoxic effect of the sonodynamic treatment with TPPS-NPs and SWs was investigated on the human neuroblastoma cell line, SH-SY5Y. Cells were exposed for 12 hours to TPPS-NPs (100 μg/mL) and then to SWs (0.43 mJ/mm2 for 500 impulses, 4 impulses/second). Treatment with SWs, TPPS, and NPs alone or in combination was carried out as control. Results There was a statistically significant decrease in SH-SY5Y cell proliferation after the sonodynamic treatment with TPPS-NPs and SWs. Indeed, there was a significant increase in necrotic (16.91% ± 3.89%) and apoptotic (27.45% ± 3.03%) cells at 48 hours. Moreover, a 15-fold increase in reactive oxygen species production for cells exposed to TPPS-NPs and SWs was observed at 1 hour compared with untreated cells. A statistically significant enhanced mRNA (messenger ribonucleic acid) expression of NRF2 (P<0.001) and a significant downregulation of TIGAR (P<0.05) and MAP3K5 (P<0.05) genes was observed in cells exposed to TPPS-NPs and SWs at 24 hours, along with a statistically significant release of cytochrome c (P<0.01) at 48 hours. Lastly, the sonosensitizing system was also investigated in an in vitro three-dimensional model, and the sonodynamic treatment significantly decreased the neuroblastoma spheroid growth. Conclusion The sonosensitizing properties of TPPS were significantly enhanced once loaded onto NPs, thus enhancing the

Irinotecan and 5-fluorouracil-co-loaded, hyaluronic acid-modified layer-by-layer nanoparticles for targeted gastric carcinoma therapy

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Gao Z

2017-09-01

Full Text Available Zhuanglei Gao,1 Zhaoxia Li,2 Jieke Yan,3 Peilin Wang1 1Department of General Surgery, 2Department of Pediatrics, 3Department of Renal Transplantation, The Second Hospital of Shandong University, Jinan, Shandong, People’s Republic of China Abstract: For targeted gastric carcinoma therapy, hyaluronic acid (HA-modified layer-by-layer nanoparticles (NPs are applied for improving anticancer treatment efficacy and reducing toxicity and side effects. The aim of this study was to develop HA-modified NPs for the co-loading of irinotecan (IRN and 5-fluorouracil (5-FU. A novel polymer–chitosan (CH–HA hybrid formulation (HA–CH–IRN/5-FU NPs consisting of poly(D,L-lactide-co-glycolide (PLGA and IRN as the core, CH and 5-FU as a shell on the core and HA as the outmost layer was prepared. Its morphology, average size, zeta potential and drug encapsulation ability were evaluated. Human gastric carcinoma cells (MGC803 cells and cancer-bearing mice were used for the testing of in vitro cytotoxicity and in vivo antitumor efficiency of NPs. HA–CH–IRN/5-FU NPs displayed enhanced antitumor activity in vitro and in vivo than non-modified NPs, single drug-loaded NPs and drugs solutions. The results demonstrate that HA–CH–IRN/5-FU NPs can achieve impressive antitumor activity and the novel targeted drug delivery system offers a promising strategy for the treatment of gastric cancer. Keywords: gastric carcinoma, irinotecan, 5-fluorouracil, hyaluronic acid, layer-by-layer nanoparticles

Investigation and Prediction of RF Window Performance in APT Accelerators

International Nuclear Information System (INIS)

Humphries, S. Jr.

1997-01-01

The work described in this report was performed between November 1996 and May 1997 in support of the APT (Accelerator Production of Tritium) Program at Los Alamos National Laboratory. The goal was to write and to test computer programs for charged particle orbits in RF fields. The well-documented programs were written in portable form and compiled for standard personal computers for easy distribution to LANL researchers. They will be used in several APT applications including the following. Minimization of multipactor effects in the moderate β superconducting linac cavities under design for the APT accelerator. Investigation of suppression techniques for electron multipactoring in high-power RF feedthroughs. Modeling of the response of electron detectors for the protection of high power RF vacuum windows. In the contract period two new codes, Trak-RF and WaveSim, were completed and several critical benchmark etests were carried out. Trak-RF numerically tracks charged particle orbits in combined electrostatic, magnetostatic and electromagnetic fields. WaveSim determines frequency-domain RF field solutions and provides a key input to Trak-RF. The two-dimensional programs handle planar or cylindrical geometries. They have several unique characteristics

Reactive oxygen species acts as executor in radiation enhancement and autophagy inducing by AgNPs.

Science.gov (United States)

Wu, Hao; Lin, Jun; Liu, Peidang; Huang, Zhihai; Zhao, Peng; Jin, Haizhen; Ma, Jun; Wen, Longping; Gu, Ning

2016-09-01

Malignant glioma is one of the most common intracranial tumor with a dismal prognosis. The radiosensitizing effect of silver nanoparticles (AgNPs) on glioma both in vitro and in vivo were demonstrated in the previous studies of our group. However, the underlying mechanism is still unclear. In this present study, the use of antioxidants is employed for the regulating of reactive oxygen species (ROS) in U251 cells treated with various agents, and the results shows that ROS played an essential role in the autophagy inducing and radiosensitization effect of AgNPs. Moreover, the inhibition of protective autophagy with 3-MA is another way to increase ROS, resulting in the increasing of cell death and apoptosis. Taken together, understanding the relationship between the elevated ROS and autophagy and the effect of ROS should be useful to the clinical applications of AgNPs. These findings could potentially be exploited for new therapeutic strategies in glioma radiotherapy. Copyright © 2016 Elsevier Ltd. All rights reserved.

The Dynamic Environment of Crypto Markets: The Lifespan of New Psychoactive Substances (NPS) and Vendors Selling NPS

OpenAIRE

Elle Wadsworth; Colin Drummond; Paolo Deluca

2018-01-01

The Internet has played a major role in the distribution of New Psychoactive Substances (NPS), and crypto markets are increasingly used for the anonymous sale of drugs, including NPS. This study explores the availability of individual NPS and vendors on the crypto markets and considers whether crypto markets are a reliable platform for the sale of NPS. Data was collected from 22 crypto markets that were accessed through the hidden web using the Onion Router (Tor). Data collection took place b...

Development of silane grafted ZnO core shell nanoparticles loaded diglycidyl epoxy nanocomposites film for antimicrobial applications.

Science.gov (United States)

Suresh, S; Saravanan, P; Jayamoorthy, K; Ananda Kumar, S; Karthikeyan, S

2016-07-01

In this article a series of epoxy nanocomposites film were developed using amine functionalized (ZnO-APTES) core shell nanoparticles as the dispersed phase and a commercially available epoxy resin as the matrix phase. The functional group of the samples was characterized using FT-IR spectra. The most prominent peaks of epoxy resin were found in bare epoxy and in all the functionalized ZnO dispersed epoxy nanocomposites (ZnO-APTES-DGEBA). The XRD analysis of all the samples exhibits considerable shift in 2θ, intensity and d-spacing values but the best and optimum concentration is found to be 3% ZnO-APTES core shell nanoparticles loaded epoxy nanocomposites supported by FT-IR results. From TGA measurements, 100wt% residue is obtained in bare ZnO nanoparticles whereas in ZnO core shell nanoparticles grafted DGEBA residue percentages are 37, 41, 45, 46 and 52% for 0, 1, 3, 5 and 7% ZnO-APTES-DGEBA respectively, which is confirmed with ICP-OES analysis. From antimicrobial activity test, it was notable that antimicrobial activity of 7% ZnO-APTES core shell nanoparticles loaded epoxy nanocomposite film has best inhibition zone effect against all pathogens under study. Copyright © 2016 Elsevier B.V. All rights reserved.

Enhanced anticancer activity and oral bioavailability of ellagic acid through encapsulation in biodegradable polymeric nanoparticles

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Mady FM

2017-10-01

Full Text Available Fatma M Mady,1,2 Mohamed A Shaker1,3 1Pharmaceutics and Pharmaceutical Technology Department, College of Pharmacy, Taibah University, Al Madina Al Munawara, Saudi Arabia; 2Pharmaceutics Department, Faculty of Pharmacy, Minia University, Minia, 3Pharmaceutics Department, Faculty of Pharmacy, Helwan University, Cairo, Egypt Abstract: Despite the fact that various studies have investigated the clinical relevance of ellagic acid (EA as a naturally existing bioactive substance in cancer therapy, little has been reported regarding the efficient strategy for improving its oral bioavailability. In this study, we report the formulation of EA-loaded nanoparticles (EA-NPs to find a way to enhance its bioactivity as well as bioavailability after oral administration. Poly(ε-caprolactone (PCL was selected as the biodegradable polymer for the formulation of EA-NPs through the emulsion–diffusion–evaporation technique. The obtained NPs have been characterized by measuring particle size, zeta potential, Fourier transform infrared, differential scanning calorimetry, and X-ray diffraction. The entrapment efficiency and the release profile of EA was also determined. In vitro cellular uptake and cytotoxicity of the obtained NPs were evaluated using Caco-2 and HCT-116 cell lines, respectively. Moreover, in vivo study has been performed to measure the oral bioavailability of EA-NPs compared to free EA, using New Zealand white rabbits. NPs with distinct shape were obtained with high entrapment and loading efficiencies. Diffusion-driven release profile of EA from the prepared NPs was determined. EA-NP-treated HCT-116 cells showed relatively lower cell viability compared to free EA-treated cells. Fluorometric imaging revealed the cellular uptake and efficient localization of EA-NPs in the nuclear region of Caco-2 cells. In vivo testing revealed that the oral administration of EA-NPs produced a 3.6 times increase in the area under the curve compared to that of EA

Smart polymeric nanoparticles with pH-responsive and PEG-detachable properties for co-delivering paclitaxel and survivin siRNA to enhance antitumor outcomes.

Science.gov (United States)

Jin, Mingji; Jin, Guangming; Kang, Lin; Chen, Liqing; Gao, Zhonggao; Huang, Wei

2018-01-01

The co-delivery of chemotherapeutic agents and small interfering RNA (siRNA) within one cargo can enhance the anticancer outcomes through its synergistic therapeutic effects. We prepared smart polymeric nanoparticles (NPs) with pH-responsive and poly(ethylene glycol) (PEG)-detachable properties to systemically co-deliver paclitaxel (PTX) and siRNA against survivin gene for lung cancer therapy. The cationic polyethyleneimine-block-polylactic acid (PEI-PLA) was first synthesized and characterized, with good biocompatibility. PTX was encapsulated into the hydrophobic core of the PEI-PLA polymers by dialysis, and then the survivin siRNA was loaded onto the PTX-loaded NPs (PEI-PLA/PTX) through electrostatic interaction between siRNA and PEI block. Finally, the negatively charged poly(ethylene glycol)-block-poly(L-aspartic acid sodium salt) (PEG-PAsp) was coated onto the surface of NPs by electrostatic interaction to form final smart polymeric NPs with mean particle size of 82.4 nm and zeta potential of 4.1 mV. After uptake of NPs by tumor cells, the PEG-PAsp segments became electrically neutral owing to the lower endosome pH and consequently detached from the smart NPs. This process allowed endosomal escape of the NPs through the proton-sponge effect of the exposed PEI moiety. The resulting NPs achieved drug loading of 6.04 wt% and exhibited good dispersibility within 24 h in 10% fetal bovine serum (FBS). At pH 5.5, the NPs presented better drug release and cellular uptake than at pH 7.4. The NPs with survivin siRNA effectively knocked down the expression of survivin mRNA and protein owing to enhanced cell uptake of NPs. Cell counting kit-8 (CCK-8) assay showed that the NPs presented low systemic toxicity and improved antiproliferation effect of PTX on A549 cells. Moreover, in vivo studies demonstrated that accumulated NPs in the tumor site were capable of inhibiting the tumor growth and extending the survival rate of the mice by silencing the survivin gene and

One-step synthesis of graphene-Au nanoparticle hybrid materials from metal salt-loaded micelles

International Nuclear Information System (INIS)

Liu, X; Zhang, X W; Meng, J H; Wang, H L; Yin, Z G; Wu, J L; Gao, H L

2014-01-01

In this study, we present a facile one-step method to synthesize graphene-Au nanoparticle (NP) hybrid materials by using HAuCl 4 -loaded poly(styrene)-block-poly(2-vinylpyridine) (PS-P2VP) micelles as solid carbon sources. N-doped graphene with controllable thickness can be grown from PS-P2VP micelles covered by a Ni capping layer by an annealing process; simultaneously, the HAuCl 4 in the micelles were reduced into Au NPs under a reductive atmosphere to form Au NPs on graphene. The decoration of Au NPs leads to an obviously enhanced electrical conductivity and a slightly increased work function of graphene due to the electron transfer effect. The graphene-Au NP hybrid materials also exhibit a localized surface plasmon resonance feature of Au NPs. This work provides a novel and accessible route for the one-step synthesis of graphene-Au NP hybrid materials with high quality, which might be useful for future applications in optoelectronic devices. (paper)

NPS transportation innovative finance options

Science.gov (United States)

2013-05-01

This paper provides a summary of innovative transportation finance techniques and discusses their applicability to the National Park Service (NPS). The primary finding of this analysis is that while NPS is engaging in innovative finance techniques su...

Study of nonpoint source nutrient loading in the Patuxent River basin, Maryland

Science.gov (United States)

Preston, S.D.

1997-01-01

Study of nonpoint-source (NPS) nutrient loading in Maryland has focused on the Patuxent watershed because of its importance and representativeness of conditions in the State. Evaluation of NPS nutrient loading has been comprehensive and has included long-term monitoring, detailed watershed modeling, and synoptic sampling studies. A large amount of information has been compiled for the watershed and that information is being used to identify primary controls and efficient management strategies for NPS nutrient loading. Results of the Patuxent NPS study have identified spatial trends in water quality that appear to be related to basin charcteristics such as land use, physiography, andgeology. Evaluation of the data compiled by the study components is continuing and is expected to provide more detailed assessments of the reasons for spatial trends. In particular, ongoing evaluation of the watershed model output is expected to provide detailed information on the relative importance of nutrient sources and transport pathways across the entire watershed. Planned future directions of NPS evaluation in the State of Maryland include continued study of water quality in the Patuxent watershed and a shift in emphasis to a statewide approach. Eventually, the statewide approach will become the primary approach usedby the State to evaluate NPS loading. The information gained in the Patuxent study and the tools developed will represent valuable assets indeveloping the statewide NPS assessment program.

Cinacalcet: AMG 073, Calcimimetics--Amgen/NPS Pharmaceuticals, KRN 1493, NPS 1493.

Science.gov (United States)

2003-01-01

Cinacalcet [AMG 073, KRN 1493, NPS 1493] is an orally active, second-generation calcimimetic compound licensed by NPS Pharmaceuticals to Amgen in the US for potential treatment of hyperparathyroidism (HPT). Cinacalcet modulates (increases the sensitivity of) calcium receptors on the surface of parathyroid cells thereby inhibiting the oversecretion of parathyroid hormone, which characterises HPT. It also represents a potentially significant advance for chronic kidney disease patients diagnosed with secondary HPT, a common yet serious metabolic disorder where parathyroid hormone levels are elevated. Patients with this disease can suffer from bone disease, bone pain and fractures, soft tissue calcification, vascular calcification and cardiovascular complications. Amgen has rights to develop and sell cinacalcet throughout the world except in Japan, Taiwan and China, where the compound was licensed to Kirin Brewery. Kirin is developing it as KRN 1493 in phase II clinical studies in Japan. In December 2001, commencement of a phase III clinical trial with cinacalcet for the treatment of secondary HPT, triggered a 3 million US dollars milestone payment to NPS Pharmaceuticals. In September 2003, submission of an NDA to the US FDA for cinacalcet for secondary HPT will be followed by a milestone payment of 6 million US dollars to NPS. NPS, Kirin and Amgen were also developing another compound, tecalcet, for HPT, but that project has been discontinued in favour of cinacalcet. In September 2003, Amgen submitted an NDA to the US FDA for secondary HPT in patients with chronic kidney disease. In April 2003, Amgen announced positive results from a phase III clinical trial with cinacalcet in patients with secondary HPT. In a clinical study in patients on dialysis suffering from the effects of chronically elevated levels parathyroid hormone, cinacalcet appeared to be safe and well tolerated and was significantly more effective than placebo. Two more additional efficacy studies with

Anisotropic In Situ-Coated AuNPs on Screen-Printed Carbon Surface for Enhanced Prostate-Specific Antigen Impedimetric Aptasensor

Science.gov (United States)

Do, Tram T. N.; Van Phi, Toan; Nguy, Tin Phan; Wagner, Patrick; Eersels, Kasper; Vestergaard, Mun'delanji C.; Truong, Lien T. N.

2017-06-01

An impedimetric aptasensor has been used to study the effect of charge transfer on the binding of prostate-specific antigen (PSA) to its aptamer. Full understanding of this mechanism will be beneficial to further improve its sensitivity for PSA detection in human semen at physiologically relevant concentrations. Bare gold electrodes (SPAuEs) and gold nanoparticles (AuNPs)-coated screen-printed carbon ink electrodes (AuNPs/SPCEs) were coated with aptamer solution at various concentrations and the sensor response to increasing PSA concentration in buffer solution examined. AuNPs were deposited onto carbon electrodes in 10 cycles. AuNPs/SPCEs were then coated with a self-assembled monolayer (SAM) of 16-mercaptohexadecanoic acid prior to aptamer immobilization at dose of 5 μg mL-1. The results indicate that anisotropic AuNPs/SPCEs outperform bare gold electrodes in terms of decreased amount of aptamer bunches as well as the number of intermediate PSA-aptamer complexes formed on the electrode surface. The key finding is that the fabricated aptasensor is sensitive enough [limit of detection (LoD) 1.95 ng mL-1] for early diagnosis of prostate cancer and displays linear response in the physiologically relevant concentration range (0 ng mL-1 to 10 ng mL-1), as shown by the calibration curve of the relative change in electron transfer resistance (Δ R CT) versus PSA concentration when aptamer/SAM/AuNPs/SPCEs were exposed to buffer containing PSA at different concentrations.

Aptámeros: agentes diagnósticos y terapéuticos = Aptamers: diagnostic and therapeutic agents

Directory of Open Access Journals (Sweden)

Frank J Hernandez

2012-04-01

Full Text Available Los aptámeros son ácidos nucleicos de cadena sencilla, ADN o ARN, que reconocen una gran variedad de moléculas. Cada aptámero posee una estructura tridimensional particular que le permite unirse con afinidad y especificidad altas a la molécula diana. Los aptámeros tienen propiedades de reconocimiento equiparables a las de los anticuerpos; sin embargo, por la naturaleza de su composición tienen ventajas significativas en cuanto a su tamaño, producción y modificación. Estas características los hacen excelentes candidatos para el desarrollo de nuevas plataformas biotecnológicas. Se han identificado aptámeros con propiedades terapéuticas que han sido evaluados exitosamente en modelos animales; entre ellos, algunos se encuentran en fase clínica y uno ya fue aprobado para tratamiento por la FDA (Food and Drug Administration. Todos estos avances ocurridos durante las dos últimas décadas permiten anticipar el protagonismo que tendrán los aptámeros como agentes diagnósticos y terapéuticos en un futuro cercano.

Fabrication of ITO-rGO/Ag NPs nanocomposite by two-step chronoamperometry electrodeposition and its characterization as SERS substrate

International Nuclear Information System (INIS)

Wang, Rong; Xu, Yi; Wang, Chunyan; Zhao, Huazhou; Wang, Renjie; Liao, Xin; Chen, Li; Chen, Gang

2015-01-01

Highlights: • A novel structure of ITO-rGO/Ag NPs substrate was developed for SERS application. • Two-step chronoamperometry deposition method was used to prepare SERS substrate. • The SERS substrate had high SERS activity, good uniformity and reproducibility. - Abstract: A novel composite structure of reduced graphene oxide (rGO)–Ag nanoparticles (Ag NPs) nanocomposite, which was integrated on the indium tin oxide (ITO) glass by a facile and rapid two-step chronoamperometry electrodeposition route, was proposed and developed in this paper. SERS-activity of the rGO/Ag NPs nanocomposite was mainly affected by the structure and size of the fabricated rGO/Ag NPs nanocomposite. In the experiments, the operational conditions of electrodeposition process were studied in details. The electrodeposited time was the important controllable factor, which decided the particle size and surface coverage of the deposited Ag NPs on ITO glass. Under the optimized conditions, the detection limit for rhodamine6G (R6G) was as low as 10 −11 M and the Raman enhancement factor was as large as 5.9 × 10 8 , which was 24 times higher than that for the ITO–Ag NPs substrate. Apart from this higher enhancement effect, it was also illustrated that extremely good uniformity and reproducibility with low standard deviation could be obtained by the prepared ITO-rGO/Ag NPs nanocomposite for SRES detection

An integrated buccal delivery system combining chitosan films impregnated with peptide loaded PEG-b-PLA nanoparticles.

Science.gov (United States)

Giovino, Concetta; Ayensu, Isaac; Tetteh, John; Boateng, Joshua S

2013-12-01

Peptide (insulin) loaded nanoparticles (NPs) have been embedded into buccal chitosan films (Ch-films-NPs). These films were produced by solvent casting and involved incorporating in chitosan gel (1.25% w/v), NPs-Insulin suspensions at three different concentrations (1, 3, and 5mg of NPs per film) using glycerol as plasticiser. Film swelling and mucoadhesion were investigated using 0.01M PBS at 37°C and texture analyzer, respectively. Formulations containing 3mg of NPs per film produced optimised films with excellent mucoadhesion and swelling properties. Dynamic laser scattering measurements showed that the erosion of the chitosan backbone controlled the release of NPs from the films, preceding in vitro drug (insulin) release from Ch-films-NPs after 6h. Modulated release was observed with 70% of encapsulated insulin released after 360h. The use of chitosan films yielded a 1.8-fold enhancement of ex vivo insulin permeation via EpiOral™ buccal tissue construct relative to the pure drug. Flux and apparent permeation coefficient of 0.1μg/cm(2)/h and 4×10(-2)cm(2)/h were respectively obtained for insulin released from Ch-films-NPs-3. Circular dichroism and FTIR spectroscopy demonstrated that the conformational structure of the model peptide drug (insulin) released from Ch-films-NPs was preserved during the formulation process. Copyright © 2013 Elsevier B.V. All rights reserved.

Induction of apoptosis in HeLa cancer cells by an ultrasonic-mediated synthesis of curcumin-loaded chitosan-alginate-STPP nanoparticles.

Science.gov (United States)

Ahmadi, Fatemeh; Ghasemi-Kasman, Maryam; Ghasemi, Shahram; Gholamitabar Tabari, Maryam; Pourbagher, Roghayeh; Kazemi, Sohrab; Alinejad-Mir, Ali

2017-01-01

Natural herbal compounds have been widely introduced as an alternative therapeutic approach in cancer therapy. Despite potent anticancer activity of curcumin, its clinical application has been limited because of low water solubility and resulting poor bioavailability. In this study, we designed a novel ultrasonic-assisted method for the synthesis of curcumin-loaded chitosan-alginate-sodium tripolyphosphate nanoparticles (CS-ALG-STPP NPs). Furthermore, antitumor effect of curcumin-loaded NPs was evaluated in vitro. Field emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM) were used to characterize the properties of NPs. Antitumor activity of curcumin-loaded NPs was assessed by using MTT and quantitative real-time polymerase chain reaction (qRT-PCR). FE-SEM and AFM data revealed the spherical morphology, and the average size of NPs was curcumin-loaded CS-ALG-STPP NPs displayed significant antitumor activity compared with the free curcumin. Gene expression level analyses showed that curcumin NPs significantly increased the apoptotic gene expression. Collectively, our results suggest that curcumin-loaded NPs significantly suppressed proliferation and promoted the induction of apoptosis in human cervical epithelioid carcinoma cancer cells, which might be regarded as an effective alternative strategy for cancer therapy.

Induction of apoptosis in HeLa cancer cells by an ultrasonic-mediated synthesis of curcumin-loaded chitosan–alginate–STPP nanoparticles

Science.gov (United States)

Ahmadi, Fatemeh; Ghasemi-Kasman, Maryam; Ghasemi, Shahram; Gholamitabar Tabari, Maryam; Pourbagher, Roghayeh; Kazemi, Sohrab; Alinejad-Mir, Ali

2017-01-01

Natural herbal compounds have been widely introduced as an alternative therapeutic approach in cancer therapy. Despite potent anticancer activity of curcumin, its clinical application has been limited because of low water solubility and resulting poor bioavailability. In this study, we designed a novel ultrasonic-assisted method for the synthesis of curcumin-loaded chitosan–alginate–sodium tripolyphosphate nanoparticles (CS-ALG-STPP NPs). Furthermore, antitumor effect of curcumin-loaded NPs was evaluated in vitro. Field emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM) were used to characterize the properties of NPs. Antitumor activity of curcumin-loaded NPs was assessed by using MTT and quantitative real-time polymerase chain reaction (qRT-PCR). FE-SEM and AFM data revealed the spherical morphology, and the average size of NPs was curcumin-loaded CS-ALG-STPP NPs displayed significant antitumor activity compared with the free curcumin. Gene expression level analyses showed that curcumin NPs significantly increased the apoptotic gene expression. Collectively, our results suggest that curcumin-loaded NPs significantly suppressed proliferation and promoted the induction of apoptosis in human cervical epithelioid carcinoma cancer cells, which might be regarded as an effective alternative strategy for cancer therapy. PMID:29238191

NPS-SCAT CONOPS and Radiation Environment

Science.gov (United States)

2012-06-01

flexibility, as well as allows players in the space market who would otherwise not be able to enter due to budgetary limitations. Important to NPS is...commercial market . Although the time frame for completing NPS-SCAT has not been as short as possible due to the nature of the learning environment on its...Program ( STP ) seeks flight opportunities for approved experiments. The current NPS- SCAT launch date offers ample time to finish and test the

Precise engineering of dapivirine-loaded nanoparticles for the development of anti-HIV vaginal microbicides.

Science.gov (United States)

das Neves, José; Sarmento, Bruno

2015-05-01

Polymeric nanoparticles (NPs) have the potential to provide effective and safe delivery of antiretroviral drugs in the context of prophylactic anti-HIV vaginal microbicides. Dapivirine-loaded poly(d,l-lactic-co-glycolic acid) (PLGA) NPs were produced by an emulsion-solvent evaporation method, optimized for colloidal properties using a 3-factor, 3-level Box-Behnken experimental design, and characterized for drug loading, production yield, morphology, thermal behavior, drug release, in vitro cellular uptake, cytotoxicity and pro-inflammatory potential. Also, drug permeability/membrane retention in well-established HEC-1-A and CaSki cell monolayer models as mediated by NPs was assessed in the absence or presence of mucin. Box-Behnken design allowed optimizing monodisperse 170nm drug-loaded NPs. Drug release experiments showed an initial burst effect up to 4h, followed by sustained 24h release at pH 4.2 and 7.4. NPs were readily taken up by different genital and macrophage cell lines as assessed by fluorescence microscopy. Drug-loaded NPs presented lower or at least similar cytotoxicity as compared to the free drug, with up to around one-log increase in half-maximal cytotoxic concentration values. In all cases, no relevant changes in cell pro-inflammatory cytokine/chemokine production were observed. Dapivirine transport across cell monolayers was significantly decreased when mucin was present at the donor side with either NPs or the free drug, thus evidencing the influence of this natural glycoprotein in membrane permeability. Moreover, drug retention in cell monolayers was significantly higher for NPs in comparison with the free drug. Overall, obtained dapivirine-loaded PLGA NPs possess interesting technological and biological features that may contribute to their use as novel safe and effective vaginal microbicides. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

NPS: Medical Consequences Associated with Their Intake.

Science.gov (United States)

Schifano, Fabrizio; Orsolini, Laura; Papanti, Duccio; Corkery, John

2017-01-01

Over the last decade, the 'traditional' drug scene has been supplemented - but not replaced - by the emergence of a range of novel psychoactive substances (NPS), which are either newly created or existing drugs, including medications, now being used in novel ways. By the end of 2014, in excess of 500 NPS had been reported by a large number of countries in the world. Most recent data show, however, that synthetic cathinones, synthetic cannabinoids, and psychedelics/phenethylamines account for the largest number of NPS.The present chapter aims at providing an overview of the clinical and pharmacological issues relating to these most popular NPS categories. Given the vast range of medical and psychopathological issues associated with the molecules here described, it is crucial for health professionals to be aware of the effects and toxicity of NPS. A general overview of the acute management of NPS adverse events is provided as well, although further studies are required to identify a range of evidence-based, index molecule-focused, treatment strategies. The rapid pace of change in the NPS online market constitutes a major challenge to the provision of current and reliable scientific knowledge on these substances.

Defining clusters in APT reconstructions of ODS steels.

Science.gov (United States)

Williams, Ceri A; Haley, Daniel; Marquis, Emmanuelle A; Smith, George D W; Moody, Michael P

2013-09-01

Oxide nanoclusters in a consolidated Fe-14Cr-2W-0.3Ti-0.3Y₂O₃ ODS steel and in the alloy powder after mechanical alloying (but before consolidation) are investigated by atom probe tomography (APT). The maximum separation method is a standard method to define and characterise clusters from within APT data, but this work shows that the extent of clustering between the two materials is sufficiently different that the nanoclusters in the mechanically alloyed powder and in the consolidated material cannot be compared directly using the same cluster selection parameters. As the cluster selection parameters influence the size and composition of the clusters significantly, a procedure to optimise the input parameters for the maximum separation method is proposed by sweeping the d(max) and N(min) parameter space. By applying this method of cluster parameter selection combined with a 'matrix correction' to account for trajectory aberrations, differences in the oxide nanoclusters can then be reliably quantified. Copyright © 2012 Elsevier B.V. All rights reserved.

APT, The Phase I tool for HST Cycle 12

Science.gov (United States)

Blacker, Brett S.; Bertch, Maria; Curtis, Gary; Douglas, Robert E., Jr.; Krueger, Anthony P.

2002-12-01

In the continuing effort to streamline our systems and improve service to the science community, the Space Telescope Science Institute (STScI) is developing and releasing, APT The Astronomer’s Proposal Tool as the new interface for Hubble Space Telescope (HST) Phase I and Phase II proposal submissions for HST Cycle 12. APT, was formerly called the Scientist’s Expert Assistant (SEA), which started as a prototype effort to try and bring state of the art technology, more visual tools and power into the hands of proposers so that they can optimize the scientific return of their programs as well as HST. Proposing for HST and other missions, consists of requesting observing time and/or archival research funding. This step is called Phase I, where the scientific merit of a proposal is considered by a community based peer-review process. Accepted proposals then proceed thru Phase II, where the observations are specified in sufficient detail to enable scheduling on the telescope. In this paper, we will present our concept and implementation plans for our Phase I development and submission tool, APT. More importantly, we will go behind the scenes and discuss why it’s important for the Science Policies Division (SPD) and other groups at the STScI to have a new submission tool and submission output products. This paper is an update of the status of the HST Phase I Proposal Processing System that was described in the published paper “A New Era for HST Phase I Development and Submission.”

The aptness of knowledge related metaphors: a research agenda

NARCIS (Netherlands)

Dr. Daan Andriessen

2010-01-01

Metaphors are common phenomena intellectual capital and knowledge management theories and practice. An important question to ask is: what are the ‗best‘ metaphors we can use in our theorizing on intellectual capital and knowledge management? This paper addresses the question of the aptness of

Enhanced sensitivity fibre Bragg grating (FBG) load sensor

International Nuclear Information System (INIS)

Correia, Ricardo; Chehura, Edmon; Li, Jin; James, Stephen W; Tatam, Ralph P

2010-01-01

The characterization of a load sensor based on the transverse loading of a subsection of a fibre Bragg grating (FBG) embedded within a cube of epoxy resin is presented. When the epoxy resin cube is loaded transverse to the axis of the fibre, its deformation transduces the load to a strain along the axis of the optical fibre, which changes the period of the embedded section of the FBG. This creates a spectral dropout within the bandwidth of the FBG, with an absolute wavelength that is linearly dependent on the applied load. This technique enhances the sensitivity of the FBG to transverse loading by a factor of 15, to 2.9 × 10 −2 ± 0.01 nm N −1 , when compared to the direct transverse loading of a bare fibre, and also protects the fibre from mechanical damage at the loading point

Development and evaluation of triclosan loaded poly-ε-caprolactone nanoparticulate system for the treatment of periodontal infections

International Nuclear Information System (INIS)

Aminu, Nafiu; Baboota, Sanjula; Pramod, K.; Singh, Manisha; Dang, Shweta; Ansari, Shahid H.; Sahni, Jasjeet K.; Ali, Javed

2013-01-01

Periodontal disease affects tooth-supporting structures and nanoparticles (NPs) have been a promising approach for its treatment. The purpose of the study was to develop triclosan-loaded poly-ε-caprolactone (PCL) NPs for the treatment of periodontal infections. Solvent displacement method was used to prepare NPs following Box–Behnken design. The NPs were evaluated with respect to particle size, polydispersity index, surface morphology, zeta potential, thermal properties, in vitro drug release, and cell viability assay. The optimized NPs were in the size range of 180–230 nm with a mean size of 205.61 ± 10.4 nm. Entrapment efficiency (EE) of 91.02 ± 2.4 % was obtained with a drug loading of 21.71 ± 1.3 %. About 97 % of drug was released in vitro after 3 h. NPs demonstrated almost 100 % cell viability in L929 cell lines. Shelf life of the nanoparticles was 17.07 months. PCL affected particle size whereas triclosan affected loading and EE. The optimized NPs were spherical with smooth surface and exhibited biphasic in vitro release pattern. NPs had optimum zeta potential and PDI and were stable on storage. Absence of cytotoxicity of NPs to L929 cells indicated its safety. Triclosan-loaded PCL nanoparticles could thus serve as a novel colloidal drug delivery system against periodontal infections

Development and evaluation of triclosan loaded poly-ε-caprolactone nanoparticulate system for the treatment of periodontal infections

Energy Technology Data Exchange (ETDEWEB)

Aminu, Nafiu; Baboota, Sanjula; Pramod, K. [Jamia Hamdard, Department of Pharmaceutics, Faculty of Pharmacy (India); Singh, Manisha; Dang, Shweta [Jaypee Institute of Information Technology, Department of Biotechnology (India); Ansari, Shahid H. [Jamia Hamdard, Department of Pharmacognosy and Phytochemistry, Faculty of Pharmacy (India); Sahni, Jasjeet K.; Ali, Javed, E-mail: javedaali@yahoo.com [Jamia Hamdard, Department of Pharmaceutics, Faculty of Pharmacy (India)

2013-11-15

Periodontal disease affects tooth-supporting structures and nanoparticles (NPs) have been a promising approach for its treatment. The purpose of the study was to develop triclosan-loaded poly-ε-caprolactone (PCL) NPs for the treatment of periodontal infections. Solvent displacement method was used to prepare NPs following Box–Behnken design. The NPs were evaluated with respect to particle size, polydispersity index, surface morphology, zeta potential, thermal properties, in vitro drug release, and cell viability assay. The optimized NPs were in the size range of 180–230 nm with a mean size of 205.61 ± 10.4 nm. Entrapment efficiency (EE) of 91.02 ± 2.4 % was obtained with a drug loading of 21.71 ± 1.3 %. About 97 % of drug was released in vitro after 3 h. NPs demonstrated almost 100 % cell viability in L929 cell lines. Shelf life of the nanoparticles was 17.07 months. PCL affected particle size whereas triclosan affected loading and EE. The optimized NPs were spherical with smooth surface and exhibited biphasic in vitro release pattern. NPs had optimum zeta potential and PDI and were stable on storage. Absence of cytotoxicity of NPs to L929 cells indicated its safety. Triclosan-loaded PCL nanoparticles could thus serve as a novel colloidal drug delivery system against periodontal infections.

The Analysis of Income Per Capita Convergence on ASEAN Plus Three (APT) Countries

OpenAIRE

Fatiwetunusa, Any; Syamsurijal, Syamsurijal; Yuliana, Sa’adah

2017-01-01

The main objective of this study is to test the convergence of income per capita in APT countries through three models: absolute convergence, conditional convergence and sigma convergence. Regression analysis of panel data from 13 APT countries during the period of 2001-2014 is used to analysed to study problem. In absolute convergence model, the growth of real GDP per capita and initial real GDP are used as the variables, meanwhile, 8 variables such as the growth of real GPD per capita, init...

Applying Amide Proton Transfer MR Imaging to Hybrid Brain PET/MR: Concordance with Gadolinium Enhancement and Added Value to [18F]FDG PET.

Science.gov (United States)

Sun, Hongzan; Xin, Jun; Zhou, Jinyuan; Lu, Zaiming; Guo, Qiyong

2018-06-01

The purpose of this study is to evaluate the diagnostic concordance and metric correlations of amide proton transfer (APT) imaging with gadolinium-enhanced magnetic resonance imaging (MRI) and 2-deoxy-2-[ 18 F-]fluoro-D-glucose ([ 18 F]FDG) positron emission tomography (PET), using hybrid brain PET/MRI. Twenty-one subjects underwent brain gadolinium-enhanced [ 18 F]FDG PET/MRI prospectively. Imaging accuracy was compared between unenhanced MRI, MRI with enhancement, APT-weighted (APTW) images, and PET based on six diagnostic criteria. Among tumors, the McNemar test was further used for concordance assessment between gadolinium-enhanced imaging, APT imaging, and [ 18 F]FDG PET. As well, the relation of metrics between APT imaging and PET was analyzed by the Pearson correlation analysis. APT imaging and gadolinium-enhanced MRI showed superior and similar diagnostic accuracy. APTW signal intensity and gadolinium enhancement were concordant in 19 tumors (100 %), while high [ 18 F]FDG avidity was shown in only 12 (63.2 %). For the metrics from APT imaging and PET, there was significant correlation for 13 hypermetabolic tumors (P PET in the evaluation of tumor metabolic activity during brain PET/MR studies.

Fabrication of ITO-rGO/Ag NPs nanocomposite by two-step chronoamperometry electrodeposition and its characterization as SERS substrate

Energy Technology Data Exchange (ETDEWEB)

Wang, Rong [Chemistry and Chemical Engineering College, Chongqing University, Shapingba, Chongqing 400044 (China); Key Disciplines Lab of Novel Micro-Nano Devices and System Technology, and School of Optoelectronics Engineering, Chongqing University, Shapingba, Chongqing 400044 (China); Analytical and Testing Center, Sichuan University of Science & Engineering, Zigong, Sichuan 643000 (China); Xu, Yi [Chemistry and Chemical Engineering College, Chongqing University, Shapingba, Chongqing 400044 (China); Key Disciplines Lab of Novel Micro-Nano Devices and System Technology, and School of Optoelectronics Engineering, Chongqing University, Shapingba, Chongqing 400044 (China); Wang, Chunyan [Key Disciplines Lab of Novel Micro-Nano Devices and System Technology, and School of Optoelectronics Engineering, Chongqing University, Shapingba, Chongqing 400044 (China); School of Optoelectronic Engineering, Chongqing University, Shapingba, Chongqing 400044 (China); Zhao, Huazhou; Wang, Renjie; Liao, Xin [Chemistry and Chemical Engineering College, Chongqing University, Shapingba, Chongqing 400044 (China); Key Disciplines Lab of Novel Micro-Nano Devices and System Technology, and School of Optoelectronics Engineering, Chongqing University, Shapingba, Chongqing 400044 (China); Chen, Li; Chen, Gang [Key Disciplines Lab of Novel Micro-Nano Devices and System Technology, and School of Optoelectronics Engineering, Chongqing University, Shapingba, Chongqing 400044 (China); School of Optoelectronic Engineering, Chongqing University, Shapingba, Chongqing 400044 (China)

2015-09-15

Highlights: • A novel structure of ITO-rGO/Ag NPs substrate was developed for SERS application. • Two-step chronoamperometry deposition method was used to prepare SERS substrate. • The SERS substrate had high SERS activity, good uniformity and reproducibility. - Abstract: A novel composite structure of reduced graphene oxide (rGO)–Ag nanoparticles (Ag NPs) nanocomposite, which was integrated on the indium tin oxide (ITO) glass by a facile and rapid two-step chronoamperometry electrodeposition route, was proposed and developed in this paper. SERS-activity of the rGO/Ag NPs nanocomposite was mainly affected by the structure and size of the fabricated rGO/Ag NPs nanocomposite. In the experiments, the operational conditions of electrodeposition process were studied in details. The electrodeposited time was the important controllable factor, which decided the particle size and surface coverage of the deposited Ag NPs on ITO glass. Under the optimized conditions, the detection limit for rhodamine6G (R6G) was as low as 10{sup −11} M and the Raman enhancement factor was as large as 5.9 × 10{sup 8}, which was 24 times higher than that for the ITO–Ag NPs substrate. Apart from this higher enhancement effect, it was also illustrated that extremely good uniformity and reproducibility with low standard deviation could be obtained by the prepared ITO-rGO/Ag NPs nanocomposite for SRES detection.

Dual drug-loaded paclitaxel–thymoquinone nanoparticles for effective breast cancer therapy

Energy Technology Data Exchange (ETDEWEB)

Soni, Parth; Kaur, Jasmine; Tikoo, Kulbhushan, E-mail: tikoo.k@gmail.com [National Institute of Pharmaceutical Education and Research (NIPER), Laboratory of Epigenetics and Diseases, Department of Pharmacology and Toxicology (India)

2015-01-15

The present study highlights the beneficial synergistic blend of anticancer drug paclitaxel (PTX) and thymoquinone (TQ) in MCF-7 breast cancer cells. We aimed to augment the therapeutic index of PTX using a polymeric nanoparticle system loaded with PTX and TQ. PLGA nanoparticles encapsulating the two drugs, individually or in combination, were prepared by single emulsion solvent evaporation method. The formulated nanoparticles were homogenous with an overall negative charge and their size ranging between 200 and 300 nm. Entrapment efficiency of PTX and TQ in the dual drug-loaded nanoparticles was found to be 82.4 ± 2.18 and 65.8 ± 0.45 %, respectively. The release kinetics of PTX and TQ from the nanoparticles exhibited a biphasic pattern characterised by an initial burst, followed by a gradual and continuous release. The anticancer activity of nanoparticles encapsulating both the drugs was higher as compared to the free drugs in MCF-7 breast cancer cells. The combination index for the dual drug-loaded NPs was found to be 0.688 which is indicative of synergistic interaction. Thus, here, we propose the synthesis and use of dual drug-loaded TQ and PTX NPs which exhibits enhanced anticancer activity and can additionally help to alleviate the toxic effects of PTX by lowering its effective dose.

Dual drug-loaded paclitaxel–thymoquinone nanoparticles for effective breast cancer therapy

International Nuclear Information System (INIS)

Soni, Parth; Kaur, Jasmine; Tikoo, Kulbhushan

2015-01-01

The present study highlights the beneficial synergistic blend of anticancer drug paclitaxel (PTX) and thymoquinone (TQ) in MCF-7 breast cancer cells. We aimed to augment the therapeutic index of PTX using a polymeric nanoparticle system loaded with PTX and TQ. PLGA nanoparticles encapsulating the two drugs, individually or in combination, were prepared by single emulsion solvent evaporation method. The formulated nanoparticles were homogenous with an overall negative charge and their size ranging between 200 and 300 nm. Entrapment efficiency of PTX and TQ in the dual drug-loaded nanoparticles was found to be 82.4 ± 2.18 and 65.8 ± 0.45 %, respectively. The release kinetics of PTX and TQ from the nanoparticles exhibited a biphasic pattern characterised by an initial burst, followed by a gradual and continuous release. The anticancer activity of nanoparticles encapsulating both the drugs was higher as compared to the free drugs in MCF-7 breast cancer cells. The combination index for the dual drug-loaded NPs was found to be 0.688 which is indicative of synergistic interaction. Thus, here, we propose the synthesis and use of dual drug-loaded TQ and PTX NPs which exhibits enhanced anticancer activity and can additionally help to alleviate the toxic effects of PTX by lowering its effective dose

Modification of silicon nitride surfaces with GOPES and APTES for antibody immobilization: computational and experimental studies

International Nuclear Information System (INIS)

To, Thien Dien; Nguyen, Anh Tuan; Phan, Khoa Nhat Thanh; Truong, An Thu Thi; Doan, Tin Chanh Duc; Dang, Chien Mau

2015-01-01

Chemical modification of silicon nitride (SiN) surfaces by silanization has been widely studied especially with 3-(aminopropyl)triethoxysilane (APTES) and 3-(glycidyloxypropyl) dimethylethoxysilane (GOPES). However few reports performed the experimental and computational studies together. In this study, surface modification of SiN surfaces with GOPES and APTES covalently bound with glutaraldehyde (GTA) was investigated for antibody immobilization. The monoclonal anti-cytokeratin-FITC (MACF) antibody was immobilized on the modified SiN surfaces. The modified surfaces were characterized by water contact angle measurements, atomic force microscopy and fluorescence microscopy. The FITC-fluorescent label indicated the existence of MACF antibody on the SiN surfaces and the efficiency of the silanization reaction. Absorption of APTES and GOPES on the oxidized SiN surfaces was computationally modeled and calculated by Materials Studio software. The computational and experimental results showed that modification of the SiN surfaces with APTES and GTA was more effective than the modification with GOPES. (paper)

Evaluation of medical isotope production with the accelerator production of tritium (APT) facility

International Nuclear Information System (INIS)

Benjamin, R.W.; Frey, G.D.; McLean, D.C., Jr; Spicer, K.M.; Davis, S.E.; Baron, S.; Frysinger, J.R.; Blanpied, G.; Adcock, D.

1997-01-01

The accelerator production of tritium (APT) facility, with its high beam current and high beam energy, would be an ideal supplier of radioisotopes for medical research, imaging, and therapy. By-product radioisotopes will be produced in the APT window and target cooling systems and in the tungsten target through spallation, neutron, and proton interactions. High intensity proton fluxes are potentially available at three different energies for the production of proton- rich radioisotopes. Isotope production targets can be inserted into the blanket for production of neutron-rich isotopes. Currently, the major production sources of radioisotopes are either aging or abroad, or both. The use of radionuclides in nuclear medicine is growing and changing, both in terms of the number of nuclear medicine procedures being performed and in the rapidly expanding range of procedures and radioisotopes used. A large and varied demand is forecast, and the APT would be an ideal facility to satisfy that demand

Power system security enhancement through direct non-disruptive load control

Science.gov (United States)

Ramanathan, Badri Narayanan

The transition to a competitive market structure raises significant concerns regarding reliability of the power grid. A need to build tools for security assessment that produce operating limit boundaries for both static and dynamic contingencies is recognized. Besides, an increase in overall uncertainty in operating conditions makes corrective actions at times ineffective leaving the system vulnerable to instability. The tools that are in place for stability enhancement are mostly corrective and suffer from lack of robustness to operating condition changes. They often pose serious coordination challenges. With deregulation, there have also been ownership and responsibility issues associated with stability controls. However, the changing utility business model and the developments in enabling technologies such as two-way communication, metering, and control open up several new possibilities for power system security enhancement. This research proposes preventive modulation of selected loads through direct control for power system security enhancement. Two main contributions of this research are the following: development of an analysis framework and two conceptually different analysis approaches for load modulation to enhance oscillatory stability, and the development and study of algorithms for real-time modulation of thermostatic loads. The underlying analysis framework is based on the Structured Singular Value (SSV or mu) theory. Based on the above framework, two fundamentally different approaches towards analysis of the amount of load modulation for desired stability performance have been developed. Both the approaches have been tested on two different test systems: CIGRE Nordic test system and an equivalent of the Western Electric Coordinating Council test system. This research also develops algorithms for real-time modulation of thermostatic loads that use the results of the analysis. In line with some recent load management programs executed by utilities, two

Docetaxel-loaded PLGA and PLGA-PEG nanoparticles for intravenous application: pharmacokinetics and biodistribution profile.

Science.gov (United States)

Rafiei, Pedram; Haddadi, Azita

2017-01-01

Docetaxel is a highly potent anticancer agent being used in a wide spectrum of cancer types. There are important matters of concern regarding the drug's pharmacokinetics related to the conventional formulation. Poly(lactide- co -glycolide) (PLGA) is a biocompatible/biodegradable polymer with variable physicochemical characteristics, and its application in human has been approved by the United States Food and Drug Administration. PLGA gives polymeric nanoparticles with unique drug delivery characteristics. The application of PLGA nanoparticles (NPs) as intravenous (IV) sustained-release delivery vehicles for docetaxel can favorably modify pharmacokinetics, biofate, and pharmacotherapy of the drug in cancer patients. Surface modification of PLGA NPs with poly(ethylene glycol) (PEG) can further enhance NPs' long-circulating properties. Herein, an optimized fabrication approach has been used for the preparation of PLGA and PLGA-PEG NPs loaded with docetaxel for IV application. Both types of NP formulations demonstrated in vitro characteristics that were considered suitable for IV administration (with long-circulating sustained-release purposes). NP formulations were IV administered to an animal model, and docetaxel's pharmacokinetic and biodistribution profiles were determined and compared between study groups. PLGA and PEGylated PLGA NPs were able to modify the pharmacokinetics and biodistribution of docetaxel. Accordingly, the mode of changes made to pharmacokinetics and biodistribution of docetaxel is attributed to the size and surface properties of NPs. NPs contributed to increased blood residence time of docetaxel fulfilling their role as long-circulating sustained-release drug delivery systems. Surface modification of NPs contributed to more pronounced docetaxel blood concentration, which confirms the role of PEG in conferring long-circulation properties to NPs.

Systemic co-delivery of doxorubicin and siRNA using nanoparticles conjugated with EGFR-specific targeting peptide to enhance chemotherapy in ovarian tumor bearing mice

Energy Technology Data Exchange (ETDEWEB)

Liu, C. W.; Lin, W. J., E-mail: wjlin@ntu.edu.tw [National Taiwan University, Graduate Institute of Pharmaceutical Sciences, School of Pharmacy (China)

2013-10-15

This aim of this study was to develop peptide-conjugated nanoparticles (NPs) for systemic co-delivery of siRNA and doxorubicin to enhance chemotherapy in epidermal growth factor receptor (EGFR) high-expressed ovarian tumor bearing mice. The active targeting NPs were prepared using heptapeptide-conjugated poly(d,l-lactic-co-glycolic acid)-poly(ethylene glycol). The particle sizes of peptide-free and peptide-conjugated NPs were 159.3 {+-} 32.5 and 184.0 {+-} 52.9 nm, respectively, with zeta potential -21.3 {+-} 3.8 and -15.3 {+-} 2.8 mV. The peptide-conjugated NPs uptake were more efficient in EGFR high-expressed SKOV3 cells than in EGFR low-expressed HepG2 cells due to heptapeptide specificity. The NPs were used to deliver small molecule anticancer drug (e.g., doxorubicin) and large molecule genetic agent (e.g., siRNA). The IC{sub 50} of doxorubicin-loaded peptide-conjugated NPs (0.09 {+-} 0.06 {mu}M) was significantly lower than peptide-free NPs (5.72 {+-} 2.64 {mu}M). The similar result was observed in siRNA-loaded NPs. The peptide-conjugated NPs not only served as a nanocarrier to efficiently deliver doxorubicin and siRNA to EGFR high-expressed ovarian cancer cells but also increased the intracellular accumulation of the therapeutic agents to induce assured anti-tumor growth effect in vivo.

Paclitaxel-loaded KMnF3 nanoparticles for cancer imaging and therapy in vivo

Science.gov (United States)

Song, Xiao-xia; Wan, Hong-ping; Zhang, Jin-sheng; Tang, Qun

2014-11-01

Biocompatible nanoparticles (NPs) responding to the light, thermal, or magnetic excitation are attracting more attention for diagnosis and therapy of cancer. Design of an effective multifunctional complex based on those NPs is a key issue to be addressed, for example, integration of anti-tumor agents with nanoprobes has been considered as one of the successful strategies for combined cancer diagnosis and therapy. In this paper, we develop paclitaxel (PTX)-loaded PEGylation KMnF3 NP, with the size ranged from 18 to 23 nm, as MRI contrast agents for cancer imaging and drug delivery for chemotherapy. Preliminary cell tests demonstrated that PTX@PEG-KMnF3 NP is highly biocompatible. The NP has high loading capacity of PTX (0.7 mg PTX/mg Mn ions), enhanced solubility of PTX (0.16 mg PTX/ml vs 0.02 mg PTX/ml), and high releasing ratio (90 %) in the weak acid solution. As it was applied for in vivo imaging and therapy, the NP enhanced contrast of tumor's MR images and PTX's anti-tumor effect profoundly. The signal noise ratio of the cancer image increased 170 % as comparison to pre-injection with the injection dose of 1.15 mg Mn/kg. The drug delivery's efficacy was also substantially improved, as the tumor growth inhibition effects reached 50 %, meanwhile only 30 % for pristine PTX. Our studies suggest that PTX-loaded KMnF3 NP might be useful as MR image-guided drug delivery for tumor treatment.

Biocompatible curcumin loaded PMMA-PEG/ZnO nanocomposite induce apoptosis and cytotoxicity in human gastric cancer cells.

Science.gov (United States)

Dhivya, Raman; Ranjani, Jothi; Bowen, Patrick K; Rajendhran, Jeyaprakash; Mayandi, Jeyanthinath; Annaraj, Jamespandi

2017-11-01

Although curcumin is efficient in killing cancer cells, its poor water solubility and assocaited inadequate bioavailability remain major limitations to its therapeutic application. The formulation of curcumin micellar nanoparticles (NPs) encapsulated with a biodegradable polymer promises to significantly improve curcumin's solubility, stability, and bioavailability. The past decade has witnessed the development of nanoscale curcumin delivery systems: curcumin-loaded liposomes or nanoparticles, self-microemulsifying drug delivery systems (SMEDDS), cyclodextrin inclusions, solid dispersions, nanodisks, and nanotubes. The intention of the present investigation was to enhance the bioavailability and ultimately the efficacy of curcumin by developing a curcumin loaded PMMA-PEG/ZnO bionanocomposite utilizing insoluble curcumin and poorly soluble ZnO nanoparticles. Here, the drug (curcumin) may be carry and deliver the biomolecule(s) by polymer-encapsulated ZnO NPs. Physical characteristics of these novel nanomaterials have been studied with transmission electron microscopy (TEM) and powder X-ray diffraction (XRD) in conjunction with spectral techniques. Aqueous solubility of curcumin was augmented upon conjugation with the polymer-stabilized ZnO NPs. A narrow nanocomposite particle size distribution with an average value of 40 to 90nm was found via TEM. Most importantly, the pH-responsive release of curcumin from the nano-vehicle ensures safer, more controlled delivery of the drug at physiological pH. Cytotoxic potential and cellular uptake of curcumin loaded ZnO NPs were assessed by) cell viability assay, cell cycle assays along with the cell imaging studies have been done in addition to MTT using AGS cancer cells. Hence, these studies demonstrate that the clinical potential of the Curcumin Loaded PMMA-PEG/ZnO can induce the apoptosis of cancer cells through a cell cycle mediated apoptosis corridor, which raises its probability to cure gastric cancer cells. Copyright �

Update on the methodology for Amtrak cost accounting Amtrak performance tracking (APT) : volume 2, appendices A-F.

Science.gov (United States)

2016-04-22

Each table below represents the list of Cost Centers associated with each APT Subfamily at the time the data for this report was gathered from APT in April 2016. The #701 Capital Family is not included as it does not have Cost Centers in a traditiona...

APT Blanket Detailed Bin Model Based on Initial Plate-Type Design -3D FLOWTRAN-TF Model

International Nuclear Information System (INIS)

Hamm, L.L.

1998-01-01

This report provides background information for a series of reports documenting accident scenario simulations for the Accelerator Production of Tritium (APT) blanket heat removal systems. The simulations were performed in support of the Preliminary Safety Analysis Report for the APT. This report gives a brief description of the FLOWTRAN-TF code which was used for detailed blanket bin modeling

Enhancement and suppression in the visual field under perceptual load.

Science.gov (United States)

Parks, Nathan A; Beck, Diane M; Kramer, Arthur F

2013-01-01

The perceptual load theory of attention proposes that the degree to which visual distractors are processed is a function of the attentional demands of a task-greater demands increase filtering of irrelevant distractors. The spatial configuration of such filtering is unknown. Here, we used steady-state visual evoked potentials (SSVEPs) in conjunction with time-domain event-related potentials (ERPs) to investigate the distribution of load-induced distractor suppression and task-relevant enhancement in the visual field. Electroencephalogram (EEG) was recorded while subjects performed a foveal go/no-go task that varied in perceptual load. Load-dependent distractor suppression was assessed by presenting a contrast reversing ring at one of three eccentricities (2, 6, or 11°) during performance of the go/no-go task. Rings contrast reversed at 8.3 Hz, allowing load-dependent changes in distractor processing to be tracked in the frequency-domain. ERPs were calculated to the onset of stimuli in the load task to examine load-dependent modulation of task-relevant processing. Results showed that the amplitude of the distractor SSVEP (8.3 Hz) was attenuated under high perceptual load (relative to low load) at the most proximal (2°) eccentricity but not at more eccentric locations (6 or 11°). Task-relevant ERPs revealed a significant increase in N1 amplitude under high load. These results are consistent with a center-surround configuration of load-induced enhancement and suppression in the visual field.

Enhancement and Suppression in the Visual Field under Perceptual Load

Directory of Open Access Journals (Sweden)

Nathan A Parks

2013-05-01

Full Text Available The perceptual load theory of attention proposes that the degree to which visual distractors are processed is a function of the attentional demands of a task – greater demands increase filtering of irrelevant distractors. The spatial configuration of such filtering is unknown. Here, we used steady-state visual evoked potentials (SSVEPs in conjunction with time-domain event-related potentials (ERPs to investigate the distribution of load-induced distractor suppression and task-relevant enhancement in the visual field. Electroencephalogram (EEG was recorded while subjects performed a foveal go/no-go task that varied in perceptual load. Load-dependent distractor suppression was assessed by presenting a contrast reversing ring at one of three eccentricities (2°, 6°, or 11° during performance of the go/no-go task. Rings contrast reversed at 8.3 Hz, allowing load-dependent changes in distractor processing to be tracked in the frequency-domain. ERPs were calculated to the onset of stimuli in the load task to examine load-dependent modulation of task-relevant processing. Results showed that the amplitude of the distractor SSVEP (8.3Hz was attenuated under high perceptual load (relative to low load at the most proximal (2° eccentricity but not at more eccentric locations (6˚ or 11˚. Task-relevant ERPs revealed a significant increase in N1 amplitude under high load. These results are consistent with a center-surround configuration of load-induced enhancement and suppression in the visual field.

Fab’-bearing siRNA TNFα-loaded nanoparticles targeted to colonic macrophages offer an effective therapy for experimental colitis

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Hamed, Laroui; Emilie, Viennois; Xiao, Bo; Canup, Brandon S.; Duke, Geem; Denning, Timothy L.; Didier, Merlin

2014-01-01

Patients suffering from Inflammatory Bowel Disease (IBD) are currently treated by systemic drugs that can have significant side effects. Thus, it would be highly desirable to target TNFα siRNA (a therapeutic molecule) to the inflamed tissue. Here, we demonstrate that TNFα siRNA can be efficiently loaded into nanoparticles (NPs) made of poly (lactic acid) poly (ethylene glycol) block copolymer (PLA-PEG), and that grafting of the Fab’ portion of the F4/80 Ab (Fab’-bearing) onto the NP surface via maleimide/thiol group-mediated covalent bonding improves the macrophage (MP)-targeting kinetics of the NPs to RAW264.7 cells in vitro. Direct binding was shown between MPs and the Fab’-bearing NPs. Next, we orally administered hydrogel (chitosan/alginate)-encapsulated Fab’-bearing TNFα-siRNA-loaded NPs to 3% dextran sodium sulfate (DSS)-treated mice and investigated the therapeutic effect on colitis. In vivo, the release of TNFα-siRNA-loaded NPs into the mouse colon attenuated colitis more efficiently when the NPs were covered with Fab’-bearing, compared to uncovered NPs. All DSS-induced parameters of colonic inflammation (e.g., weight loss, myeloperoxidase activity, and Iκbα accumulation) were more attenuated Fab’-bearing NPs loaded with TNFα siRNA than without the Fab’-bearing. Grafting the Fab’-bearing onto the NPs improved the kinetics of endocytosis as well as the MP-targeting ability, as indicated by flow cytometry. Collectively, our results show that Fab’-bearing PLA-PEG NPs are powerful and efficient nanosized tools for delivering siRNAs into colonic macrophages. PMID:24810114

Patterns of NPS Use and Risk Reduction in Slovenia.

Science.gov (United States)

Sande, Matej; Paš, Mina; Nahtigal, Klara; Šabić, Simona

2018-01-15

The following study presents factors influencing the decision to use/not to use new psychoactive substances (NPS), various patterns of NPS use, the problems experienced by users, and the methods for reducing the risks associated with NPS use. The study seeks to provide an in-depth look into the characteristics of NPS use and support the planning of targeted interventions in the field of NPS. The study involved 19 in-depth interviews carried out with 25 individuals divided into three subsamples in order to gain insight into the various experiences of NPS users. The interviews were conducted in Slovenia between December 2013 and October 2014. The sample was obtained by using the convenience sampling and snowball sampling methods. The main pattern of NPS use determined by the study concerned synthetic cathinones, specifically 3-MMC, with binge use spanning several days being a prominent feature. The main risks involving NPS use were: mixing various drugs, inappropriate dosing, lack of information prior to use, and the use of unknown substances. Several users spoke about effective strategies for reducing risks, such as obtaining information beforehand, using one's own implements and using only small quantities of unknown substances. Conclusions/Importance: The study revealed various factors based on which users decide to use NPS. Furthermore, users reported a number of problems resulting from NPS use, while risk reduction strategies are employed to a much lesser extent. Based on the results obtained, specific intervention efforts concerning NPS use and targeting specific groups of younger users were designed.

Intracellular localization and dynamics of Hypericin loaded PLLA nanocarriers by image correlation spectroscopy.

Science.gov (United States)

Penjweini, Rozhin; Deville, Sarah; D'Olieslaeger, Lien; Berden, Mandy; Ameloot, Marcel; Ethirajan, Anitha

2015-11-28

The study of cell-nanoparticle interactions is an important aspect for understanding drug delivery using nanocarriers. In this regard, advances in fluorescence based microscopy are useful for the investigation of temporal and spatial behavior of nanoparticles (NPs) within the intracellular environment. In this work, we focus on the delivery of the naturally-occurring hydrophobic photosensitizer Hypericin in human lung carcinoma A549 cells by using biodegradable poly L-lactic acid NPs. For the first time, Hypericin containing NPs are prepared by combining the miniemulsion technique with the solvent evaporation method. This approach yields an efficient loading of the NPs with Hypericin and allows for additional cargo molecules. To monitor the release of Hypercin from the NPs, an additional fluorescent lipophilic dye Coumarin-6 is incorporated in the NPs. Temporal and spatiotemporal image correlation spectroscopy is used to determine the fate of the NPs carrying the potential cargo. Both directed and non-directed motions are detected. By using image cross-correlation spectroscopy and specific fluorescent labeling of endosomes, lysosomes and mitochondria, the dynamics of the cargo loaded NPs in association with the organelles is studied. Copyright © 2015 Elsevier B.V. All rights reserved.

Study of surface functionalization on IDE by using 3-aminopropyl triethoxysilane (APTES) for cervical cancer detection

Science.gov (United States)

Raqeema, S.; Hashim, U.; Azizah, N.

2016-07-01

This paper presented the study of surface functionalization on IDE by using 3-Aminopropyl triethoxysilane (APTES). The DNA nanochip based interdigitated (IDE) has been proposed to optimized the sensitivity of the device due to the cervical cancer detection. The DNA nanochip will be more efficient using surface modification of TiO2 nanoparticles with 3-Aminopropyl triethoxysilane (APTES). Furthermore, APTES gain the better functionalization of the adsorption mechanism on IDE. The combination of the DNA probe and the HPV target will produce more sensitivity and speed of the DNA nanochip due to their properties. The IDE has been characterized using current-voltage (IV) measurement. This functionalization of the surface would be applicable, sensitive, selective and low cost for cervical cancer detection.

RAMI modeling of selected balance of plant systems for the proposed Accelerator Production of Tritium (APT) project

International Nuclear Information System (INIS)

Radder, J.A.; Cramer, D.S.

1997-01-01

In order to meet Department of Energy (DOE) Defense Program requirements for tritium in the 2005-2007 time frame, new production capability must be made available. The Accelerator Production of Tritium (APT) Plant is being considered as an alternative to nuclear reactor production of tritium, which has been the preferred method in the past. The proposed APT plant will use a high-power proton accelerator to generate thermal neutrons that will be captured in 3 He to produce tritium (3H). It is expected that the APT Plant will be built and operated at the DOE's Savannah River Site (SRS) in Aiken, South Carolina. Discussion is focused on Reliability, Availability, Maintainability, and Inspectability (RAMI) modeling of recent conceptual designs for balance of plant (BOP) systems in the proposed APT Plant. In the conceptual designs for balance of plant (BOP) systems in the proposed APT Plant. In the conceptual design phase, system RAMI estimates are necessary to identify the best possible system alternative and to provide a valid picture of the cost effectiveness of the proposed system for comparison with other system alternatives. RAMI estimates in the phase must necessarily be based on generic data. The objective of the RAMI analyses at the conceptual design stage is to assist the designers in achieving an optimum design which balances the reliability and maintainability requirements among the subsystems and components

Biodistribution and pharmacokinetics of dapivirine-loaded nanoparticles after vaginal delivery in mice.

Science.gov (United States)

das Neves, José; Araújo, Francisca; Andrade, Fernanda; Amiji, Mansoor; Bahia, Maria Fernanda; Sarmento, Bruno

2014-07-01

To assess the potential of polymeric nanoparticles (NPs) to affect the genital distribution and local and systemic pharmacokinetics (PK) of the anti-HIV microbicide drug candidate dapivirine after vaginal delivery. Dapivirine-loaded, poly(ethylene oxide)-coated poly(epsilon-caprolactone) (PEO-PCL) NPs were prepared by a nanoprecipitation method. Genital distribution of NPs and their ability to modify the PK of dapivirine up to 24 h was assessed after vaginal instillation in a female mouse model. Also, the safety of NPs upon daily administration for 14 days was assessed by histological analysis and chemokine/cytokine content in vaginal lavages. PEO-PCL NPs (180-200 nm) were rapidly eliminated after administration but able to distribute throughout the vagina and lower uterus, and capable of tackling mucus and penetrate the epithelial lining. Nanocarriers modified the PK of dapivirine, with higher drug levels being recovered from vaginal lavages and vaginal/lower uterine tissues as compared to a drug suspension. Systemic drug exposure was reduced when NPs were used. Also, NPs were shown safe upon administration for 14 days. Dapivirine-loaded PEO-PCL NPs were able to provide likely favorable genital drug levels, thus attesting the potential value of using this vaginal drug delivery nanosystem in the context of HIV prophylaxis.

Synthesis, characterization and catalytic activity of CoFe{sub 2}O{sub 4}-APTES-Pd magnetic recyclable catalyst

Energy Technology Data Exchange (ETDEWEB)

Demirelli, M. [Department of Chemistry, Faculty of Arts and Sciences, Yıldız Teknik University Davutpaşa Campus, Esenler, İstanbul (Turkey); Department of Chemistry, Faculty of Arts and Sciences, Fatih University, B. Cekmece, İstanbul 34500 (Turkey); Karaoğlu, E., E-mail: ebubekirkaraoglu@gmail.com [Department of Chemistry, Faculty of Arts and Sciences, Fatih University, B. Cekmece, İstanbul 34500 (Turkey); Department of Medical Biochemistry, Faculty of Medicine, Sakarya University, Korucuk, Sakarya (Turkey); Baykal, A. [Department of Chemistry, Faculty of Arts and Sciences, Fatih University, B. Cekmece, İstanbul 34500 (Turkey); Sözeri, H.; Uysal, E. [TUBITAK-UME, National Metrology Institute, PO Box 54, 41470 Gebze, Kocaeli (Turkey)

2014-01-05

Highlights: • CoFe{sub 2}O{sub 4}-APTES-Pd (0) nanocomposite, as effective catalysts for reduction reactions. • It could be reused several times without significant loss in hydrogenation reaction. • So far, CoFe{sub 2}O{sub 4}-APTES-Pd (0) nanocomposite have not been synthesized. • CoFe{sub 2}O{sub 4}-APTES-Pd (0) nanocomposite was confirmed by XRD, FT-IR. • Pd containing nanoparticles embedded in organic surfactant observed by TEM. -- Abstract: A new magnetically recyclable catalyst, CoFe{sub 2}O{sub 4}-APTES-Pd(0) nanocomposite, as highly effective catalysts for reduction reactions in liquid phase was fabricated and characterized. The reduction of Pd{sup 2+} was accomplished with sodium borohydride (NaBH{sub 4}). The chemical characterization of the product was done with X-ray diffractometry, infrared spectroscopy, transmission electron microscopy, UV–Vis spectroscopy and inductively coupled plasma. It was found that the combination of CoFe{sub 2}O{sub 4} and 3-aminopropyltriethoxysilane (APTES) could give rise to structurally stable catalytic sites. Furthermore, the high magnetization CoFe{sub 2}O{sub 4}-APTES-Pd(0) catalyst can be recovered by magnet and reused for ten runs for hydrogenation reaction of 4-nitro aniline, 1,3 dinitro and cyclohexanone. The catalyst was easily isolated from the reaction mixture by a magnetic bar and reused at least 10 times without significant degradation in the activity which shows the indicative of a potential applications of these catalysts in industry.

Facile and eco-friendly fabrication of AgNPs coated silk for antibacterial and antioxidant textiles using honeysuckle extract.

Science.gov (United States)

Zhou, Yuyang; Tang, Ren-Cheng

2018-01-01

Recently, there is a growing trend towards the functionalization of silk through nanotechnology for the prevention of fiber damage from microbial attack and the enhancement of hygienic aspects. Considering sustainable development and environmental protection, the eco-friendly fabrication of silver nanoparticles (AgNPs)-modified silk using natural extracts has currently become a hot research area. This study presents a facile strategy for the fabrication of colorful and multifunctional silk fabric using biogenic AgNPs prepared by honeysuckle extract as natural reductant and stabilizing agents. The influences of pH and reactant concentrations on the AgNPs synthesis were investigated. The color characteristics and functionalities of AgNPs treated silk were evaluated. The results revealed that the particle size of AgNPs decreased with increasing pH. The diameter of AgNPs decreased with increasing amount of honeysuckle extract and reducing amount of silver nitrate. The transmission electron microscopy image showed that the AgNPs were spherical in shape with a narrow size distribution. The treated silk showed excellent antibacterial activities against E. coli and S. aureus, and certain antioxidant activity. Both of the antibacterial and antioxidant activities were well maintained even after 30 washing cycles. This work provides a sustainable and eco-friendly approach to the fabrication of AgNPs coated silk for colorful and long-term multifunctional textiles using honeysuckle extract. Copyright © 2017 Elsevier B.V. All rights reserved.

Assessing the physical-chemical properties and stability of dapivirine-loaded polymeric nanoparticles.

Science.gov (United States)

das Neves, José; Amiji, Mansoor; Bahia, Maria Fernanda; Sarmento, Bruno

2013-11-18

Nanocarriers may provide interesting delivery platforms for microbicide drugs and their characterization should be addressed early in development. Differently surface-engineered dapivirine-loaded, poly(epsilon-caprolactone) (PCL)-based nanoparticles (NPs) were obtained by nanoprecipitation using polyethylene oxide (PEO), sodium lauryl sulfate (SLS), or cetyltrimethylammonium bromide (CTAB) as surface modifiers. Physical-chemical properties of NP aqueous dispersions were evaluated upon storage at -20-40 °C for one year. NPs presented 170-200 nm in diameter, roundish-shape, low polydispersity index (≤0.18), and high drug association efficiency (≥97%) and loading (≥12.7%). NPs differed in zeta potential, depending on surface modifier (PEO: -27.9 mV; SLS: -54.7 mV; CTAB: +42.4 mV). No interactions among formulation components were detected by differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR), except for SLS-PCL NPs. Colloidal properties of NPs were lost at -20 °C storage. Negatively charged NPs were stable up to one year at 5-40°C; as for CTAB-PCL NPs, particle aggregation was observed from 30 to 90 days of storage depending on temperature. Colloidal instability affected the in vitro drug release of CTAB-PCL NPs after 360 days. In any case, no degradation of dapivirine was apparent. Overall, PEO-PCL and SLS-PCL NPs presented suitable properties as nanocarriers for dapivirine. Conversely, CTAB-PCL NPs require additional strategies in order to increase stability. Copyright © 2013 Elsevier B.V. All rights reserved.

Recombinant IκBα-loaded curcumin nanoparticles for improved cancer therapeutics

International Nuclear Information System (INIS)

Banerjee, Subhamoy; Ghosh, Siddhartha Sankar; Sahoo, Amaresh Kumar; Chattopadhyay, Arun

2014-01-01

The field of recombinant protein therapeutics has been evolving rapidly, making significant impact on clinical applications for several diseases, including cancer. However, the functional aspects of proteins rely exclusively on their structural integrity, in which nanoparticle mediated delivery offers unique advantages over free proteins. In the present work, a novel strategy has been developed where the nanoparticles (NPs) used for the delivery of the recombinant protein could contribute to enhancing the therapeutic efficacy of the recombinant protein. The transcription factor, NFκB, involved in cell growth and its inhibitor, IκBα, regulates its proliferation. Another similar naturally available molecule, which inhibits the function of NFκB, is curcumin. Hence, we have developed a ‘green synthesis’ method for preparing water-soluble curcumin nanoparticles to stabilize recombinant IκBα protein. The NPs were characterized by UV–vis and fluorescence spectroscopy, transmission electron microscopy (TEM) and dynamic light scattering before administration into human cervical carcinoma (HeLa) and glioblastoma (U87MG) cells. Experimental results demonstrated that this combined module had enhanced therapeutic efficacy, causing apoptotic cell death, which was confirmed by cytotoxicity assay and flowcytometry analyses. The expression of apoptotic genes studied by semi-quantitative reverse transcription PCR delineated the molecular pathways involved in cell death. Thus, our study revealed that the functional delivery of recombinant IκBα-loaded curcumin NPs has promise as a natural-product-based protein therapeutics against cancer cells. (paper)

Recombinant IκBα-loaded curcumin nanoparticles for improved cancer therapeutics

Science.gov (United States)

Banerjee, Subhamoy; Sahoo, Amaresh Kumar; Chattopadhyay, Arun; Sankar Ghosh, Siddhartha

2014-08-01

The field of recombinant protein therapeutics has been evolving rapidly, making significant impact on clinical applications for several diseases, including cancer. However, the functional aspects of proteins rely exclusively on their structural integrity, in which nanoparticle mediated delivery offers unique advantages over free proteins. In the present work, a novel strategy has been developed where the nanoparticles (NPs) used for the delivery of the recombinant protein could contribute to enhancing the therapeutic efficacy of the recombinant protein. The transcription factor, NFκB, involved in cell growth and its inhibitor, IκBα, regulates its proliferation. Another similar naturally available molecule, which inhibits the function of NFκB, is curcumin. Hence, we have developed a ‘green synthesis’ method for preparing water-soluble curcumin nanoparticles to stabilize recombinant IκBα protein. The NPs were characterized by UV-vis and fluorescence spectroscopy, transmission electron microscopy (TEM) and dynamic light scattering before administration into human cervical carcinoma (HeLa) and glioblastoma (U87MG) cells. Experimental results demonstrated that this combined module had enhanced therapeutic efficacy, causing apoptotic cell death, which was confirmed by cytotoxicity assay and flowcytometry analyses. The expression of apoptotic genes studied by semi-quantitative reverse transcription PCR delineated the molecular pathways involved in cell death. Thus, our study revealed that the functional delivery of recombinant IκBα-loaded curcumin NPs has promise as a natural-product-based protein therapeutics against cancer cells.

Spatial and Seasonal Variations of Heavy Metal Loads in Uyo Urban Drainage Stream under PS and NPS Pollution

Directory of Open Access Journals (Sweden)

O. E. Essien

2012-12-01

Full Text Available The concentration of heavy metals (HM in the 4km urban drainage stream in Uyo was studied using grab and composite sampling of water from six stations on the stream, and analyzed by a multipurpose atomic absorption spectrophotometer. The data were statistically analyzed using SPSS version 17 software arid correlated between stations and among samples. HM contamination was evaluated with the coefficient and rate of dispersion between stations and the Normalized Scatter Coefficient (NSC. The seasonal distribution of metal pollution varied individually amongst metals at stations. The Fe and Pb concentrations exceeded the safe drinking water standard, rendering the water quality not acceptable for drinking; however, the quality was within the safe limit for crop production along the river bank. The relative.dominance of heavy metals followed a different sequence in upstream leachate effluent from all downstream stations. The NSC in dry-wet season was higher than in wet season, and was in the order: Fe>Cu>Zn>Pb, showing that large but variable concentration of Fe from PS and NPS contaminated the stream at faster rate in the wet season while Pb contaminated at nearly constant rate. However, in the dry season, Fe and Pb depleted at downstream at rates far higher than Zn as Cu was increasing. Fe and Pb could be good pollution monitor for total maximum daily load (TMDL pollution monitoring programme.

T cells enhance gold nanoparticle delivery to tumors in vivo

Science.gov (United States)

Kennedy, Laura C.; Bear, Adham S.; Young, Joseph K.; Lewinski, Nastassja A.; Kim, Jean; Foster, Aaron E.; Drezek, Rebekah A.

2011-12-01

Gold nanoparticle-mediated photothermal therapy (PTT) has shown great potential for the treatment of cancer in mouse studies and is now being evaluated in clinical trials. For this therapy, gold nanoparticles (AuNPs) are injected intravenously and are allowed to accumulate within the tumor via the enhanced permeability and retention (EPR) effect. The tumor is then irradiated with a near infrared laser, whose energy is absorbed by the AuNPs and translated into heat. While reliance on the EPR effect for tumor targeting has proven adequate for vascularized tumors in small animal models, the efficiency and specificity of tumor delivery in vivo, particularly in tumors with poor blood supply, has proven challenging. In this study, we examine whether human T cells can be used as cellular delivery vehicles for AuNP transport into tumors. We first demonstrate that T cells can be efficiently loaded with 45 nm gold colloid nanoparticles without affecting viability or function (e.g. migration and cytokine production). Using a human tumor xenograft mouse model, we next demonstrate that AuNP-loaded T cells retain their capacity to migrate to tumor sites in vivo. In addition, the efficiency of AuNP delivery to tumors in vivo is increased by more than four-fold compared to injection of free PEGylated AuNPs and the use of the T cell delivery system also dramatically alters the overall nanoparticle biodistribution. Thus, the use of T cell chaperones for AuNP delivery could enhance the efficacy of nanoparticle-based therapies and imaging applications by increasing AuNP tumor accumulation.

Polyaspartamide-Based Nanoparticles Loaded with Fluticasone Propionate and the In Vitro Evaluation towards Cigarette Smoke Effects

Directory of Open Access Journals (Sweden)

Emanuela Fabiola Craparo

2017-08-01

Full Text Available This paper describes the evaluation of polymeric nanoparticles (NPs as a potential carrier for lung administration of fluticasone propionate (FP. The chosen polymeric material to produce NPs was a copolymer based on α,β-poly(N-2-hydroxyethyl-d,l-aspartamide (PHEA whose backbone was derivatised with different molecules, such as poly(lactic acid (PLA and polyethylenglycol (PEG. The chosen method to produce NPs from PHEA-PLA-PEG2000 was the method based on high-pressure homogenization and subsequent solvent evaporation by adding Pluronic F68 during the process and trehalose before lyophilisation. Obtained colloidal FP-loaded NPs showed a slightly negative surface charge and nanometric dimensions that are maintained after storage for one year at −20 °C and 5 °C. The FP loading was about 2.9 wt % and the drug was slowly released in simulated lung fluid. Moreover, the obtained NPs, containing the drug or not, were biocompatible and did not induce cell necrosis and cell apoptosis on bronchial epithelial cells (16-HBE. Further in vitro testing on cigarette smoke extract (CSE-stimulated 16-HBE revealed that FP-loaded NPs were able to reduce the survivin expression, while either free FP or empty NPs were not able to significantly reduce this effect.

Cytotoxicity of ZnO NPs towards fresh water algae Scenedesmus obliquus at low exposure concentrations in UV-C, visible and dark conditions

Energy Technology Data Exchange (ETDEWEB)

Bhuvaneshwari, M.; Iswarya, V. [Centre for Nanobiotechnology, VIT University, Vellore 632014 (India); Archanaa, S. [Department of Biotechnology, IIT Madras (India); Madhu, G.M. [Department of Chemical Engineering, M.S. Ramaiah Institute of Technology, Bangalore (India); Kumar, G.K. Suraish [Department of Biotechnology, IIT Madras (India); Nagarajan, R. [Department of Chemical Engineering, IIT Madras (India); Chandrasekaran, N. [Centre for Nanobiotechnology, VIT University, Vellore 632014 (India); Mukherjee, Amitava, E-mail: amit.mookerjea@gmail.com [Centre for Nanobiotechnology, VIT University, Vellore 632014 (India)

2015-05-15

Highlights: • The cytotoxicity of ZnO NPs with two hydrodynamic sizes towards freshwater algae. • Size dependent toxicity under UV-C, dark and visible light conditions. • Cytotoxicity principally due to ZnO NPs not the released Zn{sup 2+} ions. • The internalization of ZnO NPs leads to membrane damage and ROS production. - Abstract: Continuous increase in the usage of ZnO nanoparticles in commercial products has exacerbated the risk of release of these particles into the aquatic environment with possible harmful effects on the biota. In the current study, cytotoxic effects of two types of ZnO nanoparticles, having different initial effective diameters in filtered and sterilized lake water medium [487.5 ± 2.55 nm for ZnO-1 NPs and 616.2 ± 38.5 nm for ZnO-2 NPs] were evaluated towards a dominant freshwater algal isolate Scenedesmus obliquus in UV-C, visible and dark conditions at three exposure concentrations: 0.25, 0.5 and 1 mg/L. The toxic effects were found to be strongly dependent on the initial hydrodynamic particle size in the medium, the exposure concentrations and the irradiation conditions. The loss in viability, LDH release and ROS generation were significantly enhanced in the case of the smaller sized ZnO-1 NPs than in the case of ZnO-2 NPs under comparable test conditions. The toxicity of both types of ZnO NPs was considerably elevated under UV-C irradiation in comparison to that in dark and visible light conditions, the effects being more enhanced in case of ZnO-1 NPs. The size dependent dissolution of the ZnO NPs in the test medium and possible toxicity due to the released Zn{sup 2+} ions was also noted. The surface adsorption of the nanoparticles was substantiated by scanning electron microscopy. The internalization/uptake of the NPs by the algal cells was confirmed by fluorescence microscopy, transmission electron microscopy, and elemental analyses.

Cytotoxicity of ZnO NPs towards fresh water algae Scenedesmus obliquus at low exposure concentrations in UV-C, visible and dark conditions

International Nuclear Information System (INIS)

Bhuvaneshwari, M.; Iswarya, V.; Archanaa, S.; Madhu, G.M.; Kumar, G.K. Suraish; Nagarajan, R.; Chandrasekaran, N.; Mukherjee, Amitava

2015-01-01

Highlights: • The cytotoxicity of ZnO NPs with two hydrodynamic sizes towards freshwater algae. • Size dependent toxicity under UV-C, dark and visible light conditions. • Cytotoxicity principally due to ZnO NPs not the released Zn 2+ ions. • The internalization of ZnO NPs leads to membrane damage and ROS production. - Abstract: Continuous increase in the usage of ZnO nanoparticles in commercial products has exacerbated the risk of release of these particles into the aquatic environment with possible harmful effects on the biota. In the current study, cytotoxic effects of two types of ZnO nanoparticles, having different initial effective diameters in filtered and sterilized lake water medium [487.5 ± 2.55 nm for ZnO-1 NPs and 616.2 ± 38.5 nm for ZnO-2 NPs] were evaluated towards a dominant freshwater algal isolate Scenedesmus obliquus in UV-C, visible and dark conditions at three exposure concentrations: 0.25, 0.5 and 1 mg/L. The toxic effects were found to be strongly dependent on the initial hydrodynamic particle size in the medium, the exposure concentrations and the irradiation conditions. The loss in viability, LDH release and ROS generation were significantly enhanced in the case of the smaller sized ZnO-1 NPs than in the case of ZnO-2 NPs under comparable test conditions. The toxicity of both types of ZnO NPs was considerably elevated under UV-C irradiation in comparison to that in dark and visible light conditions, the effects being more enhanced in case of ZnO-1 NPs. The size dependent dissolution of the ZnO NPs in the test medium and possible toxicity due to the released Zn 2+ ions was also noted. The surface adsorption of the nanoparticles was substantiated by scanning electron microscopy. The internalization/uptake of the NPs by the algal cells was confirmed by fluorescence microscopy, transmission electron microscopy, and elemental analyses

Dispersed-nanoparticle loading synthesis for monodisperse Au-titania composite particles and their crystallization for highly active UV and visible photocatalysts.

Science.gov (United States)

Sakamoto, Takeshi; Nagao, Daisuke; Noba, Masahiro; Ishii, Haruyuki; Konno, Mikio

2014-06-24

Submicrometer-sized amorphous titania spheres incorporating Au nanoparticles (NPs) were prepared in a one-pot synthesis consisting of a sol-gel reaction of titanium(IV) isopropoxide in the presence of chloroauric acid and a successive reduction with sodium borohydride in a mixed solvent of ethanol/acetonitrile. The synthesis was allowed to prepare monodisperse titania spheres that homogeneously incorporated Au NPs with sizes of ca. 7 nm. The Au NP-loaded titania spheres underwent different crystallization processes, including 500 °C calcination in air, high-temperature hydrothermal treatment (HHT), and/or low-temperature hydrothermal treatment (LHT). Photocatalytic experiments were conducted with the Au NP-loaded crystalline titania spheres under irradiation of UV and visible light. A combined process of LHT at 80 °C followed by calcination at 500 °C could effectively crystallize titania spheres maintaining the dispersion state of Au NPs, which led to photocatalytic activity higher than that of commercial P25 under UV irradiation. Under visible light irradiation, the Au NP-titania spheres prepared with a crystallization process of LHT at 80 °C for 6 h showed photocatalytic activity much higher than a commercial product of visible light photocatalyst. Structure analysis of the visible light photocatalysts indicates the importance of prevention of the Au NPs aggregation in the crystallization processes for enhancement of photocatalytic activity.

SN-38 loading capacity of hydrophobic polymer blend nanoparticles: formulation, optimization and efficacy evaluation.

Science.gov (United States)

Dimchevska, Simona; Geskovski, Nikola; Petruševski, Gjorgji; Chacorovska, Marina; Popeski-Dimovski, Riste; Ugarkovic, Sonja; Goracinova, Katerina

2017-03-01

One of the most important problems in nanoencapsulation of extremely hydrophobic drugs is poor drug loading due to rapid drug crystallization outside the polymer core. The effort to use nanoprecipitation, as a simple one-step procedure with good reproducibility and FDA approved polymers like Poly(lactic-co-glycolic acid) (PLGA) and Polycaprolactone (PCL), will only potentiate this issue. Considering that drug loading is one of the key defining characteristics, in this study we attempted to examine whether the nanoparticle (NP) core composed of two hydrophobic polymers will provide increased drug loading for 7-Ethyl-10-hydroxy-camptothecin (SN-38), relative to NPs prepared using individual polymers. D-optimal design was applied to optimize PLGA/PCL ratio in the polymer blend and the mode of addition of the amphiphilic copolymer Lutrol ® F127 in order to maximize SN-38 loading and obtain NPs with acceptable size for passive tumor targeting. Drug/polymer and polymer/polymer interaction analysis pointed to high degree of compatibility and miscibility among both hydrophobic polymers, providing core configuration with higher drug loading capacity. Toxicity studies outlined the biocompatibility of the blank NPs. Increased in vitro efficacy of drug-loaded NPs compared to the free drug was confirmed by growth inhibition studies using SW-480 cell line. Additionally, the optimized NP formulation showed very promising blood circulation profile with elimination half-time of 7.4 h.

Amide Proton Transfer (APT) MR imaging and Magnetization Transfer (MT) MR imaging of pediatric brain development

International Nuclear Information System (INIS)

Zhang, Hong; Kang, Huiying; Peng, Yun; Zhao, Xuna; Jiang, Shanshan; Zhang, Yi; Zhou, Jinyuan

2016-01-01

To quantify the brain maturation process during childhood using combined amide proton transfer (APT) and conventional magnetization transfer (MT) imaging at 3 Tesla. Eighty-two neurodevelopmentally normal children (44 males and 38 females; age range, 2-190 months) were imaged using an APT/MT imaging protocol with multiple saturation frequency offsets. The APT-weighted (APTW) and MT ratio (MTR) signals were quantitatively analyzed in multiple brain areas. Age-related changes in MTR and APTW were evaluated with a non-linear regression analysis. The APTW signals followed a decreasing exponential curve with age in all brain regions measured (R"2 = 0.7-0.8 for the corpus callosum, frontal and occipital white matter, and centrum semiovale). The most significant changes appeared within the first year. At maturation, larger decreases in APTW and lower APTW values were found in the white matter. On the contrary, the MTR signals followed an increasing exponential curve with age in the same brain regions measured, with the most significant changes appearing within the initial 2 years. There was an inverse correlation between the MTR and APTW signal intensities during brain maturation. Together with MT imaging, protein-based APT imaging can provide additional information in assessing brain myelination in the paediatric population. (orig.)

Amide Proton Transfer (APT) MR imaging and Magnetization Transfer (MT) MR imaging of pediatric brain development

Energy Technology Data Exchange (ETDEWEB)

Zhang, Hong; Kang, Huiying; Peng, Yun [Beijing Children' s Hospital, Capital Medical University, Imaging Center, Department of Radiology, Beijing (China); Zhao, Xuna [Philips Healthcare, Beijing (China); Jiang, Shanshan; Zhang, Yi; Zhou, Jinyuan [Johns Hopkins University, Division of MR Research, Department of Radiology, Baltimore, MD (United States)

2016-10-15

To quantify the brain maturation process during childhood using combined amide proton transfer (APT) and conventional magnetization transfer (MT) imaging at 3 Tesla. Eighty-two neurodevelopmentally normal children (44 males and 38 females; age range, 2-190 months) were imaged using an APT/MT imaging protocol with multiple saturation frequency offsets. The APT-weighted (APTW) and MT ratio (MTR) signals were quantitatively analyzed in multiple brain areas. Age-related changes in MTR and APTW were evaluated with a non-linear regression analysis. The APTW signals followed a decreasing exponential curve with age in all brain regions measured (R{sup 2} = 0.7-0.8 for the corpus callosum, frontal and occipital white matter, and centrum semiovale). The most significant changes appeared within the first year. At maturation, larger decreases in APTW and lower APTW values were found in the white matter. On the contrary, the MTR signals followed an increasing exponential curve with age in the same brain regions measured, with the most significant changes appearing within the initial 2 years. There was an inverse correlation between the MTR and APTW signal intensities during brain maturation. Together with MT imaging, protein-based APT imaging can provide additional information in assessing brain myelination in the paediatric population. (orig.)

Enhanced antimicrobial activities of silver-nanoparticle-decorated reduced graphene nanocomposites against oral pathogens.

Science.gov (United States)

Peng, Jian-Min; Lin, Jia-Cheng; Chen, Zhuo-Yu; Wei, Meng-Chao; Fu, Yuan-Xiang; Lu, Shu-Shen; Yu, Dong-Sheng; Zhao, Wei

2017-02-01

As a means of capitalizing on the synergistic properties between reduced graphene nanosheets (R-GNs) and silver nanoparticles (AgNPs), an efficient and convenient chemical reduction method was used to prepare silver-nanoparticle-decorated reduced graphene nanocomposites (R-GNs/Ag). The products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Raman spectroscopy, which confirmed the loading of well-dispersed silver nanoparticles on reduced graphene sheets. Their antimicrobial activities against oral pathogens such as Candida albicans, Lactobacillus acidophilus, Streptococcus mutans, and Aggregatibacter actinomycetemcomitans were investigated by MIC determination, the counting of colony-forming units (CFU), agar diffusion tests, and growth curve observation. Compared with pure R-GNs and AgNPs, R-GNs/Ag composites exhibited enhanced antimicrobial properties owing to highly dispersed AgNPs on R-GNs. Copyright © 2016 Elsevier B.V. All rights reserved.

Preparation and evaluation of 17-allyamino-17-demethoxygeldanamycin (17-AAG)-loaded poly(lactic acid-co-glycolic acid) nanoparticles.

Science.gov (United States)

Pradhan, Roshan; Poudel, Bijay Kumar; Choi, Ju Yeon; Choi, Im Soon; Shin, Beom Soo; Choi, Han-Gon; Yong, Chul Soon; Kim, Jong Oh

2015-01-01

In the present study, we developed the novel 17-allyamino-17-demethoxygeldanamycin (17-AAG)-loaded poly(lactic acid-co-glycolic acid) (PLGA) nanoparticles (NPs) using the combination of sodium lauryl sulfate and poloxamer 407 as the anionic and non-ionic surfactant for stabilization. The PLGA NPs were prepared by emulsification/solvent evaporation method. Both the drug/polymer ratio and phase ratio were 1:10 (w/w). The optimized formulation of 17-AAG-loaded PLGA NPs had a particle size and polydispersity index of 151.6 ± 2.0 and 0.152 ± 0.010 nm, respectively, which was further supported by TEM image. The encapsulation efficiency and drug loading capacity were 69.9 and 7.0%, respectively. In vitro release study showed sustained release. When in vitro release data were fitted to Korsmeyer-Peppas model, the n value was 0.468, which suggested that the drug was released by anomalous or non-Fickian diffusion. In addition, 17-AAG-loaded PLGA NPs in 72 h, displayed approximately 60% cell viability reduction at 10 µg/ml 17-AAG concentration, in MCF-7 cell lines, indicating sustained release from NPs. Therefore, our results demonstrated that incorporation of 17-AAG into PLGA NPs could provide a novel effective nanocarrier for the treatment of cancer.

Curcumin-loaded nanoparticles ameliorate glial activation and improve myelin repair in lyolecithin-induced focal demyelination model of rat corpus callosum.

Science.gov (United States)

Naeimi, Reza; Safarpour, Fatemeh; Hashemian, Mona; Tashakorian, Hamed; Ahmadian, Seyed Raheleh; Ashrafpour, Manouchehr; Ghasemi-Kasman, Maryam

2018-05-01

Curcumin has been introduced as effective anti-inflammatory agent in treatment of several inflammatory disorders. Despite the wide range pharmacological activities, clinical application of curcumin is restricted mainly due to the low water solubility of this substance. More recently, we could remarkably improve the aqueous solubility of curcumin by its encapsulation in chitosan-alginate-sodium tripolyphosphate nanoparticles (CS-ALG-STPP NPs). In this study, the anti-inflammatory and myelin protective effects of curcumin-loaded NPs were evaluated in lysolecithin (LPC)-induced focal demyelination model. Pharmacokinetic of curcumin was assessed using high performance liquid chromatography (HPLC). Local demyelination was induced by injection of LPC into corpus callosum of rats. Animals were pre-treated with intraperitoneal (i.p.) injections of curcumin or curcumin-loaded NPs at dose of 12.5 mg/kg, 10 days prior to LPC injection and the injections were continued for 7 or 14 days post lesion. Hematoxylin and eosin (H&E) staining and immunostaining against activated glial cells including astrocytes and microglia were carried out for assessment of inflammation level in lesion site. Myelin specific staining was performed to evaluate the effect of curcumin-loaded NPs on myelination of LPC receiving animals. HPLC results showed the higher plasma concentration of curcumin after administration of NPs. Histological evaluation demonstrated that, the extent of demyelination areas was reduced in animals under treatment of curcumin-loaded NPs. Furthermore, treatment with curcumin-loaded NPs effectively attenuated glial activation and inflammation in LPC-induced demyelination model compared to curcumin receiving animals. Overall; these findings indicate that treatment with curcumin-loaded NPs preserve myelinated axons through amelioration of glial activation and inflammation in demyelination context. Copyright © 2018 Elsevier B.V. All rights reserved.

The Analysis of Income per Capita Convergence on ASEAN Plus Three (APT Countries

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Any Fatiwetunusa

2017-09-01

Full Text Available The main objective of this study is to test the convergence of income per capita in APT countries through three models: absolute convergence, conditional convergence and sigma convergence. Regression analysis of panel data from 13 APT countries during the period of 2001-2014 is used to analysed to study problem. In absolute convergence model, the growth of real GDP per capita and initial real GDP are used as the variables, meanwhile, 8 variables such as the growth of real GPD per capita, initial real GDP per capita, labor force ratio, value added in agricultural sector, value added in industrial sector, terms of trade, foreign direct investment and internet users ratio are analyzed in conditional convergence model. According to the Solow model, the economies of the countries will converge in which the growth of income per capita of developing countries will be higher than those of developed countries. The economies will be convergent if the countries tend to move to a similar steady state resulting in smaller gap between the countries. Based on the results of absolute convergence and conditional convergence models, APT countries is converging with the rate of 2% and 2.2%. This is consistent with the results of sigma convergence model that shows a declining trend in the dispersion of real GDP per capita in APT regions. The growth of real GDP per capita is influenced by initial GDP per capita, labor force ratio, value added in agricultural sector, value added in industrial sector, terms of trade, foreign direct investment and internet users ratio. Developed countries such as Singapore, Brunei Darussalam and South Korea experience the impact of high real GDP per capita growth. On the contrary, Indonesia, Laos, Vietnam and The Phillipines undergo the impact of low GDP per capita growth.

Smart polymeric nanoparticles with pH-responsive and PEG-detachable properties for co-delivering paclitaxel and survivin siRNA to enhance antitumor outcomes

Directory of Open Access Journals (Sweden)

Jin M

2018-04-01

Full Text Available Mingji Jin,1 Guangming Jin,2 Lin Kang,1 Liqing Chen,1 Zhonggao Gao,1 Wei Huang11State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China; 2Department of Diagnostic Radiology 2, Yanbian University Hospital, Yanji, Jilin, China Background: The co-delivery of chemotherapeutic agents and small interfering RNA (siRNA within one cargo can enhance the anticancer outcomes through its synergistic therapeutic effects. Materials and methods: We prepared smart polymeric nanoparticles (NPs with pH-responsive and poly(ethylene glycol (PEG-detachable properties to systemically co-deliver paclitaxel (PTX and siRNA against survivin gene for lung cancer therapy. The cationic polyethyleneimine-block-polylactic acid (PEI-PLA was first synthesized and characterized, with good biocompatibility. PTX was encapsulated into the hydrophobic core of the PEI-PLA polymers by dialysis, and then the survivin siRNA was loaded onto the PTX-loaded NPs (PEI-PLA/PTX through electrostatic interaction between siRNA and PEI block. Finally, the negatively charged poly(ethylene glycol-block-poly(l-aspartic acid sodium salt (PEG-PAsp was coated onto the surface of NPs by electrostatic interaction to form final smart polymeric NPs with mean particle size of 82.4 nm and zeta potential of 4.1 mV. After uptake of NPs by tumor cells, the PEG-PAsp segments became electrically neutral owing to the lower endosome pH and consequently detached from the smart NPs. This process allowed endosomal escape of the NPs through the proton-sponge effect of the exposed PEI moiety. Results: The resulting NPs achieved drug loading of 6.04 wt% and exhibited good dispersibility within 24 h in 10% fetal bovine serum (FBS. At pH 5.5, the NPs presented better drug release and cellular uptake than at pH 7.4. The NPs with survivin siRNA effectively knocked down the expression of

Enhanced Raman scattering in porous silicon grating.

Science.gov (United States)

Wang, Jiajia; Jia, Zhenhong; Lv, Changwu

2018-03-19

The enhancement of Raman signal on monocrystalline silicon gratings with varying groove depths and on porous silicon grating were studied for a highly sensitive surface enhanced Raman scattering (SERS) response. In the experiment conducted, porous silicon gratings were fabricated. Silver nanoparticles (Ag NPs) were then deposited on the porous silicon grating to enhance the Raman signal of the detective objects. Results show that the enhancement of Raman signal on silicon grating improved when groove depth increased. The enhanced performance of Raman signal on porous silicon grating was also further improved. The Rhodamine SERS response based on Ag NPs/ porous silicon grating substrates was enhanced relative to the SERS response on Ag NPs/ porous silicon substrates. Ag NPs / porous silicon grating SERS substrate system achieved a highly sensitive SERS response due to the coupling of various Raman enhancement factors.

A functional screen implicates microRNA-138-dependent regulation of the depalmitoylation enzyme APT1 in dendritic spine morphogenesis

DEFF Research Database (Denmark)

Siegel, Gabriele; Obernosterer, Gregor; Fiore, Roberto

2009-01-01

of acyl protein thioesterase 1 (APT1), an enzyme regulating the palmitoylation status of proteins that are known to function at the synapse, including the alpha(13) subunits of G proteins (Galpha(13)). RNA-interference-mediated knockdown of APT1 and the expression of membrane-localized Galpha(13) both...... suppress spine enlargement caused by inhibition of miR-138, suggesting that APT1-regulated depalmitoylation of Galpha(13) might be an important downstream event of miR-138 function. Our results uncover a previously unknown miRNA-dependent mechanism in neurons and demonstrate a previously unrecognized...

Enhancement of the Electrocatalytic Activity of Gold Nanoparticles via Anodic Treatment and the Decrease of the Enhanced Activity with Aging

International Nuclear Information System (INIS)

Jo, Kyung Min; Kang, Hyun Ju; Yang, Hae Sik

2011-01-01

We have recently shown that the electrocatalytic activity of Au nanoparticles (AuNPs) can be enhanced via NaBH 4 treatment and cathodic treatment and that the enhanced activity slowly decreases with aging. We have also demonstrated that the electrocatalytic activity of the AuNPs freshly prepared by electrochemical or chemical reduction slowly decreases with aging in both air and solution. Likewise, the electrocatalytic activity of anodically treated Au electrodes or AuNPs might change with aging. Herein, we report that the electrocatalytic activity of long-aged AuNPs can be enhanced via anodic treatment and that the enhanced electrocatalytic activity decreases with aging in air. The change in the electrocatalytic activity of AuNPs was evaluated by comparing cyclic voltammograms for the electrooxi-dation of hydrogen peroxide (H 2 O 2 ) and formic acid

Corrosion measurements on apt prototypic materials in the Lansce high-power proton beam and applicability to other systems

International Nuclear Information System (INIS)

Lillard, R.S.; Gac, F.D.; James, M.R.; Maloy, S.A.; Paciotti, M.A.; Waters, L.S.; Willcutt, G.J.; Chandler, G.T.; Ferguson, P.D.

2003-01-01

The corrosion rates of several corrosion resistant materials behave in a similar manner even under the intense radiation of the LANSCE high-power beam. A second observation was made, showing that the corrosion rates saturated under high instantaneous radiation intensity in corrosion experiments conducted for the accelerator production of tritium (APT) programme. The LANSCE H + beam is not prototypic of the proposed APT production plant in several respects. The instantaneous proton flux in the APT production plant beam is about 10 times that of the LANSCE beam. The small transverse APT beam spot is rastered to spread the power density over the area of the target, and as the beam rasters, it creates a pulsed character to the beam at a specific location. In order to develop correlations that would enable extrapolation of the corrosion data to the proposed APT production plant, the experimental programme included measurements over a range of average beam currents, measurements at high and low instantaneous beam current, and measurements at various combinations of pulse width and repetition rate. The correlations that were developed are based on an approximately linear dependence of corrosion rate on average beam current (average radiation intensity) and the saturation effect observed at high instantaneous radiation intensity. For a given transverse beam profile and for the same average beam current, the correlations predict the highest corrosion rate in a do beam and the lowest corrosion rate in the lowest duty cycle beams. In the case of the APT extrapolation, the predicted corrosion rates were a factor of 5 lower than for a do beam depositing the same average power density. The measured corrosion rates and the formulated extrapolations are applicable to water-cooled targets and components in proton beams. (authors)

Polymeric nanoparticles enhance the sonodynamic activity of meso-tetrakis (4-sulfonatophenyl porphyrin in an in vitro neuroblastoma model

Directory of Open Access Journals (Sweden)

Canaparo R

2013-11-01

Full Text Available Roberto Canaparo,1,* Greta Varchi,2,* Marco Ballestri,2 Federica Foglietta,1 Giovanna Sotgiu,2 Andrea Guerrini,2 Andrea Francovich,3 Pierluigi Civera,3 Roberto Frairia,4 Loredana Serpe1 1Department of Drug Science and Technology, University of Torino, Torino, Italy; 2Institute of the Organic Synthesis and Photoreactivity, National Research Council, Bologna, Italy; 3Departments of Electronics, Politecnico of Torino, Torino, Italy; 4Department of Medical Science, University of Torino, Torino, Italy *These authors contributed equally to this work Purpose: Sonodynamic therapy is a developing noninvasive modality for cancer treatment, based on the selective activation of a sonosensitizer agent by acoustic cavitation. The activated sonosensitizer agent might generate reactive oxygen species leading to cancer cell death. We investigated the potential poly-methyl methacrylate core-shell nanoparticles (NPs loaded with meso-tetrakis (4-sulfonatophenyl porphyrin (TPPS have to function as an innovative sonosensitizing system, ie, TPPS-NPs. Methods: Shockwaves (SWs generated by a piezoelectric device were used to induce acoustic cavitation. The cytotoxic effect of the sonodynamic treatment with TPPS-NPs and SWs was investigated on the human neuroblastoma cell line, SH-SY5Y. Cells were exposed for 12 hours to TPPS-NPs (100 µg/mL and then to SWs (0.43 mJ/mm2 for 500 impulses, 4 impulses/second. Treatment with SWs, TPPS and NPs alone or in combination was carried out as control. Results: There was a statistically significant decrease in SH-SY5Y cell proliferation after the sonodynamic treatment with TPPS-NPs and SWs. Indeed, there was a significant increase in necrotic (16.91% ± 3.89% and apoptotic (27.45% ± 3.03% cells at 48 hours. Moreover, a 15-fold increase in reactive oxygen species production for cells exposed to TPPS-NPs and SWs was observed at 1 hour compared with untreated cells. A statistically significant enhanced mRNA (messenger ribonucleic acid

Immobilized Pd-Ag bimetallic nanoparticles on polymeric nanofibers as an effective catalyst: effective loading of Ag with bimetallic functionality through Pd nucleated nanofibers

Science.gov (United States)

Shanmugam Ranjith, Kugalur; Celebioglu, Asli; Uyar, Tamer

2018-06-01

Here, we present a precise process for synthesizing Pd-Ag bimetallic nanoparticles (NPs) onto polymeric nanofibers by decorating Pd-NPs through atomic layer deposition followed by a chemical reduction process for tagging Ag nanostructures with bimetallic functionality. The results show that Pd-NPs act as a nucleation platform for tagging Ag and form Pd-Ag bimetallic NPs with a monodisperse nature with significant catalytic enhancement to the reaction rate over the bimetallic nature of the Pd-Ag ratio. A Pd-NP decorated polymeric nanofibrous web acts as an excellent platform for the encapsulation or interaction of Ag, which prevents agglomeration and promotes the interaction of Ag ions only on the surface of the Pd-NPs. We observed an effective reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) by sodium borohydride (NaBH4) to access the catalytic activity of Pd-Ag bimetallic NPs on a free-standing flexible polymeric nanofibrous web as a support. The captive formation of the polymeric nanofibrous web with Pd-Ag bimetallic functionality exhibited superior and stable catalytic performance with reduction rates of 0.0719, 0.1520, and 0.0871 min‑1 for different loadings of Ag on Pd decorated nanofibrous webs such as Pd/Ag(0.01), Pd/Ag(0.03), and Pd/Ag(0.05), respectively. The highly faceted Pd-Ag NPs with an immobilized nature improves the catalytic functionality by enhancing the binding energy of the 4-NP adsorbate to the surface of the NPs. With the aid of bimetallic functionality, the nanofibrous web was demonstrated as a hybrid heterogeneous photocatalyst with a 3.16-fold enhancement in the reaction rate as compared with the monometallic decorative nature of NaBH4 as a reducing agent. The effective role of the monodisperse nature of Pd ions with an ultralow content as low as 3 wt% and the tunable ratio of Ag on the nanofibrous web induced effective catalytic activity over multiple cycles.

Design and assembly of ternary Pt/Re/SnO2 NPs by controlling the zeta potential of individual Pt, Re, and SnO2 NPs

Science.gov (United States)

Drzymała, Elżbieta; Gruzeł, Grzegorz; Pajor-Świerzy, Anna; Depciuch, Joanna; Socha, Robert; Kowal, Andrzej; Warszyński, Piotr; Parlinska-Wojtan, Magdalena

2018-05-01

In this study Pt, Re, and SnO2 nanoparticles (NPs) were combined in a controlled manner into binary and ternary combinations for a possible application for ethanol oxidation. For this purpose, zeta potentials as a function of the pH of the individual NPs solutions were measured. In order to successfully combine the NPs into Pt/SnO2 and Re/SnO2 NPs, the solutions were mixed together at a pH guaranteeing opposite zeta potentials of the metal and oxide NPs. The individually synthesized NPs and their binary/ternary combinations were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning transmission electron microscopy (STEM) combined with energy dispersive X-ray spectroscopy (EDS) analysis. FTIR and XPS spectroscopy showed that the individually synthesized Pt and Re NPs are metallic and the Sn component was oxidized to SnO2. STEM showed that all NPs are well crystallized and the sizes of the Pt, Re, and SnO2 NPs were 2.2, 1.0, and 3.4 nm, respectively. Moreover, EDS analysis confirmed the successful formation of binary Pt/SnO2 and Re/SnO2 NP, as well as ternary Pt/Re/SnO2 NP combinations. This study shows that by controlling the zeta potential of individual metal and oxide NPs, it is possible to assemble them into binary and ternary combinations. [Figure not available: see fulltext.

Surface modification of MPEG-b-PCL-based nanoparticles via oxidative self-polymerization of dopamine for malignant melanoma therapy

Directory of Open Access Journals (Sweden)

Xiong W

2015-04-01

Full Text Available Wei Xiong,1,2 Lixia Peng,1,2 Hongbo Chen,3 Qin Li1,2 1Southern Medical University, Guangzhou, 2Department of Plastic Surgery, General Hospital of Guangzhou Military Command of PLA, Guangzhou, People’s Republic of China; 3Division of Life Sciences and Health, Graduate School at Shenzhen, Tsinghua University, Shenzhen, People’s Republic of China Abstract: To enhance the therapeutic effects of chemotherapy on malignant melanoma, paclitaxel (PTX-loaded methoxy poly(ethylene glycol-b-poly(ε-caprolactone nanoparticles (MPEG-b-PCL NPs that had their surfaces modified with polydopamine (PTX-loaded MPEG-b-PCL NPs@PDA were prepared as drug vehicles. The block copolymer MPEG-b-PCL was synthesized by ring-opening polymerization and characterized by proton nuclear magnetic resonance spectroscopy and gel permeation chromatography. The PTX-loaded NPs were prepared by a modified nanoprecipitation technique. The PTX-loaded NPs and PTX-loaded NPs@PDA were characterized in terms of size and size distribution, zeta potential, surface morphology, drug encapsulation efficiency, and drug release. Confocal laser scanning microscopy showed that coumarin-6-loaded NPs@PDA could be internalized by human melanoma cell line A875 cells. The cellular uptake efficiency of NPs was greatly enhanced after PDA modification. The antitumor efficacy of the PTX-loaded NPs@PDA was investigated in vitro by the 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT assay and in vivo by a xenograft tumor model. The PTX-loaded NPs@PDA could significantly inhibit tumor growth compared to Taxol® and precursor PTX-loaded NPs. All the results suggested that the PTX-loaded MPEG-b-PCL NPs that had their surfaces modified with PDA are promising nanocarriers for malignant melanoma therapy. Keywords: cancer nanotechnology, drug delivery, surface modification, polydopamine, malignant melanoma

Scientific and engineering services for the LANCE/ER accelerator production of tritium (APT) project

International Nuclear Information System (INIS)

1994-01-01

The APT project office is conducting a preconceptual design study for an accelerator driven concept to produce tritium. The facility will require new technology in many areas, since the scale of this accelerator is significantly larger then any in operation to date. The facility is composed of four subsystems: accelerator, target ampersand blanket, balance of plant, and tritium purification system (TPS). New physics realms will be entered in order for the concept to be feasible; for example, extremely high energy levels of the entering protons that induce (multiplicative) spallation of the neutrons from the high Z target will occur. These are complex and require advance codes (MCNP) to predict the physics interactions and as well as deleterious material effects in the surrounding structures. Other issues include component cooling and complex thermal-hydraulics effects within the blanket and the beam open-quotes window.close quotes In order to support a DOE mandated fast ROD schedule, Los Alamos APT staff will be provided with senior, engineering technical support staff with direct APT technology experience and whom are open-quotes on siteclose quotes. This report contains resumes of the staff

Discussion on the thermal conductivity enhancement of nanofluids

Science.gov (United States)

2011-01-01

Increasing interests have been paid to nanofluids because of the intriguing heat transfer enhancement performances presented by this kind of promising heat transfer media. We produced a series of nanofluids and measured their thermal conductivities. In this article, we discussed the measurements and the enhancements of the thermal conductivity of a variety of nanofluids. The base fluids used included those that are most employed heat transfer fluids, such as deionized water (DW), ethylene glycol (EG), glycerol, silicone oil, and the binary mixture of DW and EG. Various nanoparticles (NPs) involving Al2O3 NPs with different sizes, SiC NPs with different shapes, MgO NPs, ZnO NPs, SiO2 NPs, Fe3O4 NPs, TiO2 NPs, diamond NPs, and carbon nanotubes with different pretreatments were used as additives. Our findings demonstrated that the thermal conductivity enhancements of nanofluids could be influenced by multi-faceted factors including the volume fraction of the dispersed NPs, the tested temperature, the thermal conductivity of the base fluid, the size of the dispersed NPs, the pretreatment process, and the additives of the fluids. The thermal transport mechanisms in nanofluids were further discussed, and the promising approaches for optimizing the thermal conductivity of nanofluids have been proposed. PMID:21711638

Intranasal administration of carbamazepine-loaded carboxymethyl chitosan nanoparticles for drug delivery to the brain

Directory of Open Access Journals (Sweden)

Shanshan Liu

2018-01-01

Full Text Available Epilepsy is considered as a common and diverse set of chronic neurological disorders and its symptoms can be controlled by antiepileptic drugs (AEDs. The presence of p-glycoprotein and multi-drug resistance transporters in the blood-brain barrier could prevent the entry of AEDs into the brain, causing drug resistant epilepsy. To overcome this problem, we propose using carboxymethyl chitosan nanoparticles as a carrier to deliver carbamazepine (CBZ intra-nasally with the purpose to bypass the blood-brain barrier thus to enhance the brain drug concentration and the treatment efficacy. Results so far indicate that the developed CBZ-NPs have small particle size (218.76 ± 2.41 nm with high drug loading (around 35% and high entrapment efficiency (around 80%. The in vitro release profiles of CBZ from the NPs are in accordance with the Korsmeyer-peppas model. The in vivo results show that both encapsulation of CBZ in nanoparticles and the nasal route determined the enhancement of the drug bioavailability and brain targeting characteristics.

Differential Phytotoxic Impact of Plant Mediated Silver Nanoparticles (AgNPs) and Silver Nitrate (AgNO3) on Brassica sp.

Science.gov (United States)

Vishwakarma, Kanchan; Shweta; Upadhyay, Neha; Singh, Jaspreet; Liu, Shiliang; Singh, Vijay P; Prasad, Sheo M; Chauhan, Devendra K; Tripathi, Durgesh K; Sharma, Shivesh

2017-01-01

Continuous formation and utilization of nanoparticles (NPs) have resulted into significant discharge of nanosized particles into the environment. NPs find applications in numerous products and agriculture sector, and gaining importance in recent years. In the present study, silver nanoparticles (AgNPs) were biosynthesized from silver nitrate (AgNO 3 ) by green synthesis approach using Aloe vera extract. Mustard ( Brassica sp.) seedlings were grown hydroponically and toxicity of both AgNP and AgNO 3 (as ionic Ag + ) was assessed at various concentrations (1 and 3 mM) by analyzing shoot and root length, fresh mass, protein content, photosynthetic pigments and performance, cell viability, oxidative damage, DNA degradation and enzyme activities. The results revealed that both AgNPs and AgNO 3 declined growth of Brassica seedlings due to enhanced accumulation of AgNPs and AgNO 3 that subsequently caused severe inhibition in photosynthesis. Further, the results showed that both AgNPs and AgNO 3 induced oxidative stress as indicated by histochemical staining of superoxide radical and hydrogen peroxide that was manifested in terms of DNA degradation and cell death. Activities of antioxidants, i.e., ascorbate peroxidase (APX) and catalase (CAT) were inhibited by AgNPs and AgNO 3. Interestingly, damaging impact of AgNPs was lesser than AgNO 3 on Brassica seedlings which was due to lesser accumulation of AgNPs and better activities of APX and CAT, which resulted in lesser oxidative stress, DNA degradation and cell death. The results of the present study showed differential impact of AgNPs and AgNO 3 on Brassica seedlings, their mode of action, and reasons for their differential impact. The results of the present study could be implied in toxicological research for designing strategies to reduce adverse impact of AgNPs and AgNO 3 on crop plants.

Differential Phytotoxic Impact of Plant Mediated Silver Nanoparticles (AgNPs and Silver Nitrate (AgNO3 on Brassica sp.

Directory of Open Access Journals (Sweden)

Kanchan Vishwakarma

2017-10-01

Full Text Available Continuous formation and utilization of nanoparticles (NPs have resulted into significant discharge of nanosized particles into the environment. NPs find applications in numerous products and agriculture sector, and gaining importance in recent years. In the present study, silver nanoparticles (AgNPs were biosynthesized from silver nitrate (AgNO3 by green synthesis approach using Aloe vera extract. Mustard (Brassica sp. seedlings were grown hydroponically and toxicity of both AgNP and AgNO3 (as ionic Ag+ was assessed at various concentrations (1 and 3 mM by analyzing shoot and root length, fresh mass, protein content, photosynthetic pigments and performance, cell viability, oxidative damage, DNA degradation and enzyme activities. The results revealed that both AgNPs and AgNO3 declined growth of Brassica seedlings due to enhanced accumulation of AgNPs and AgNO3 that subsequently caused severe inhibition in photosynthesis. Further, the results showed that both AgNPs and AgNO3 induced oxidative stress as indicated by histochemical staining of superoxide radical and hydrogen peroxide that was manifested in terms of DNA degradation and cell death. Activities of antioxidants, i.e., ascorbate peroxidase (APX and catalase (CAT were inhibited by AgNPs and AgNO3. Interestingly, damaging impact of AgNPs was lesser than AgNO3 on Brassica seedlings which was due to lesser accumulation of AgNPs and better activities of APX and CAT, which resulted in lesser oxidative stress, DNA degradation and cell death. The results of the present study showed differential impact of AgNPs and AgNO3 on Brassica seedlings, their mode of action, and reasons for their differential impact. The results of the present study could be implied in toxicological research for designing strategies to reduce adverse impact of AgNPs and AgNO3 on crop plants.

The preparation and antibacterial effects of dopa-cotton/AgNPs

International Nuclear Information System (INIS)

Xu Hong; Shi Xue; Ma Hui; Lv Yihang; Zhang Linping; Mao Zhiping

2011-01-01

Silver nanoparticles (AgNPs) have been known to have powerful antibacterial activity. In this paper, in situ generation of AgNPs on the surface of dopamine modified cotton fabrics (dopa-cotton/AgNPs) in aqueous solution under room temperature is presented. X-ray photoelectron spectroscopy (XPS) and field emission scanning electron microscope (FE-SEM) were used to analyze the surface chemical composition and the morphology of the modified cotton fabrics, respectively. The results indicated that the surface of cotton fabrics was successfully coated with polydopamine and AgNPs. The cotton fabrics with AgNPs showed durable antibacterial activity.

NPS National Transit Inventory and Performance Report, 2016

Science.gov (United States)

2017-12-01

This document summarizes key highlights and performance measures relating to the National Park Service (NPS) 2016 National Transit Inventory, by presenting data for NPS transit systems and vehicles nationwide. These highlights and performance measure...

In vitro evaluation of paclitaxel loaded amorphous chitin nanoparticles for colon cancer drug delivery.

Science.gov (United States)

Smitha, K T; Anitha, A; Furuike, T; Tamura, H; Nair, Shantikumar V; Jayakumar, R

2013-04-01

Chitin and its derivatives have been widely used in drug delivery applications due to its biocompatible, biodegradable and non-toxic nature. In this study, we have developed amorphous chitin nanoparticles (150±50 nm) and evaluated its potential as a drug delivery system. Paclitaxel (PTX), a major chemotherapeutic agent was loaded into amorphous chitin nanoparticles (AC NPs) through ionic cross-linking reaction using TPP. The prepared PTX loaded AC NPs had an average diameter of 200±50 nm. Physico-chemical characterization of the prepared nanoparticles was carried out. These nanoparticles were proven to be hemocompatible and in vitro drug release studies showed a sustained release of PTX. Cellular internalization of the NPs was confirmed by fluorescent microscopy as well as by flow cytometry. Anticancer activity studies proved the toxicity of PTX-AC NPs toward colon cancer cells. These preliminary results indicate the potential of PTX-AC NPs in colon cancer drug delivery. Copyright © 2012 Elsevier B.V. All rights reserved.

Reducing agent-free synthesis of curcumin-loaded albumin nanoparticles by self-assembly at room temperature.

Science.gov (United States)

Safavi, Maryam Sadat; Shojaosadati, Seyed Abbas; Yang, Hye Gyeong; Kim, Yejin; Park, Eun Ji; Lee, Kang Choon; Na, Dong Hee

2017-08-30

The purpose of this study was to prepare curcumin-loaded bovine serum albumin nanoparticles (CCM-BSA-NPs) by reducing agent-free self-assembly at room temperature. A 2 4 factorial design approach was used to investigate the CCM-BSA-NP preparation process at different pH values, temperatures, dithiothreitol amounts, and CCM/BSA mass ratios. Increasing the ionic strength enabled preparation of CCM-BSA-NPs at 25°C without reducing agent. CCM-BSA-NPs prepared under the optimized conditions at 25°C showed a particle size of 110±6nm, yield of 88.5%, and drug loading of 7.1%. The CCM-BSA-NPs showed strong antioxidant activity and neuroprotective effects in glutamate-induced mouse hippocampal neuronal HT22 cells. This study suggests that ionic strength can be a key parameter affecting the preparation of albumin-based NPs. Copyright © 2017 Elsevier B.V. All rights reserved.

Antimicrobial and cell viability measurement of bovine serum albumin capped silver nanoparticles (Ag/BSA) loaded collagen immobilized poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) film.

Science.gov (United States)

Bakare, Rotimi; Hawthrone, Samantha; Vails, Carmen; Gugssa, Ayele; Karim, Alamgir; Stubbs, John; Raghavan, Dharmaraj

2016-03-01

Bacterial infection of orthopedic devices has been a major concern in joint replacement procedures. Therefore, this study is aimed at formulating collagen immobilized poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) film loaded with bovine serum albumin capped silver nanoparticles (Ag/BSA NPs) to inhibit bacterial growth while retaining/promoting osteoblast cells viability. The nanoparticles loaded collagen immobilized PHBV film was characterized for its composition by X-ray Photoelectron Spectroscopy and Anodic Stripping Voltammetry. The extent of loading of Ag/BSA NPs on collagen immobilized PHBV film was found to depend on the chemistry of the functionalized PHBV film and the concentration of Ag/BSA NPs solution used for loading nanoparticles. Our results showed that more Ag/BSA NPs were loaded on higher molecular weight collagen immobilized PHEMA-g-PHBV film. Maximum loading of Ag/BSA NPs on collagen immobilized PHBV film was observed when 16ppm solution was used for adsorption studies. Colony forming unit and optical density measurements showed broad antimicrobial activity towards Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa at significantly lower concentration i.e., 0.19 and 0.31μg/disc, compared to gentamicin and sulfamethoxazole trimethoprim while MTT assay showed that released nanoparticles from Ag/BSA NPs loaded collagen immobilized PHBV film has no impact on MCTC3-E1 cells viability. Copyright © 2015 Elsevier Inc. All rights reserved.

A highly selective and sensitive cocaine aptasensor based on covalent attachment of the aptamer-functionalized AuNPs onto nanocomposite as the support platform

Energy Technology Data Exchange (ETDEWEB)

Roushani, Mahmoud, E-mail: mahmoudroushani@yahoo.com; Shahdost-fard, Faezeh

2015-01-01

Highlights: • Functionalized thiol-terminated cocaine aptamer was functionalized with AuNPs. • MWCNTs/IL/Chit was employed for covalent attachment of Apt-capture probe onto electrode. • (K{sub 3}Fe(CN){sub 6}) was used as the redox probe and DPV as analytical technique. • The aptasensor showed high sensitivity and selectivity. • Linear range from 1 nM to 11,000 nM with LOD of 100 pM for cocaine detection was obtained. - Abstract: Based on the conformational changes of the aptamer-functionalized gold nanoparticles (AuNPs) onto MWCNTs/IL/Chit nanocomposite as the support platform, we have developed a sensitive and selective electrochemical aptasensor for the detection of cocaine. The 5′-amine-3′-AuNP terminated aptamer is covalently attached to a MWCNTs/IL/Chit nanocomposite. The interaction of cocaine with the aptamer functionalized AuNP caused the aptamer to be folded and the AuNPs with negative charge at the end of the aptamer came to the near of electrode surface therefore, the electron transfer between ferricyanide (K{sub 3}Fe(CN){sub 6}) as redox probe and electrode surface was inhibited. A decreased current of (K{sub 3}Fe(CN){sub 6}) was monitored by differential pulse voltammetry technique. In an optimized condition the calibration curve for cocaine concentration was linear up to 11 μM with detection limit (signal-to-noise ratio of 3) of 100 pM. To test the selectivity of the prepared aptasensor sensing platform applicability, some analgesic drugs as the interferes were examined. The potential of the aptasensor was successfully applied for measuring cocaine concentration in human blood serum. Based on our experiments it can be said that the present method is absolutely beneficial in developing other electrochemical aptasensor.

A highly selective and sensitive cocaine aptasensor based on covalent attachment of the aptamer-functionalized AuNPs onto nanocomposite as the support platform

International Nuclear Information System (INIS)

Roushani, Mahmoud; Shahdost-fard, Faezeh

2015-01-01

Highlights: • Functionalized thiol-terminated cocaine aptamer was functionalized with AuNPs. • MWCNTs/IL/Chit was employed for covalent attachment of Apt-capture probe onto electrode. • (K 3 Fe(CN) 6 ) was used as the redox probe and DPV as analytical technique. • The aptasensor showed high sensitivity and selectivity. • Linear range from 1 nM to 11,000 nM with LOD of 100 pM for cocaine detection was obtained. - Abstract: Based on the conformational changes of the aptamer-functionalized gold nanoparticles (AuNPs) onto MWCNTs/IL/Chit nanocomposite as the support platform, we have developed a sensitive and selective electrochemical aptasensor for the detection of cocaine. The 5′-amine-3′-AuNP terminated aptamer is covalently attached to a MWCNTs/IL/Chit nanocomposite. The interaction of cocaine with the aptamer functionalized AuNP caused the aptamer to be folded and the AuNPs with negative charge at the end of the aptamer came to the near of electrode surface therefore, the electron transfer between ferricyanide (K 3 Fe(CN) 6 ) as redox probe and electrode surface was inhibited. A decreased current of (K 3 Fe(CN) 6 ) was monitored by differential pulse voltammetry technique. In an optimized condition the calibration curve for cocaine concentration was linear up to 11 μM with detection limit (signal-to-noise ratio of 3) of 100 pM. To test the selectivity of the prepared aptasensor sensing platform applicability, some analgesic drugs as the interferes were examined. The potential of the aptasensor was successfully applied for measuring cocaine concentration in human blood serum. Based on our experiments it can be said that the present method is absolutely beneficial in developing other electrochemical aptasensor

Revelation of susceptibility differences due to Hg(II) accumulation in Streptococcus pyogenes against CX-AgNPs and Cefixime by atomic force microscopy.

Science.gov (United States)

Rasheed, Wasia; Shah, Muhammad Raza; Perveen, Samina; Ahmed, Shakil; Uzzaman, Sami

2018-01-01

Solution based method for the formation of chemically modified silver nanoparticles (CX-AgNPs) using Cefixime as stabilizing and reducing agent was developed. The CX-AgNPs were characterized by AFM, UV-visible, FT-IR and MALDI-TOF MS. Bactericidal efficiency of CX-AgNPs and Cefixime against Streptococcus pyogenes was evaluated. Afterwards, susceptibility differences of Streptococcus pyogenes due to accumulation of Hg(II) against CX-AgNPs and Cefixime were estimated and validated through Atomic force microscopy. Selectivity and sensitivity of CX-AgNPs against Hg(II) was evaluated in a systematic manner. The CX-AgNPs was titrated against optically silent Hg(II) which induced enhancement in the SPR band of CX-AgNPs. The increase in intensity of SPR band of CX-AgNPs was determined to be proportionate to the concentration of Hg(II) in the range of 33.3-700µM obeying linear regression equation of y = 0.125x + 8.962 with the detection limit of 0.10µM and the coefficient of determination equals to 0.985 (n = 3). The association constant Ka of CX-AgNPs-Hg(II) was found to be 386.0095mol -1 dm 3 by using the Benesi Hildebrand plot. Copyright © 2017 Elsevier Inc. All rights reserved.

NPS-SCAT (Solar Cell Array Tester), The Construction of NPS' First Prototype CubeSat

National Research Council Canada - National Science Library

Bein, Alexander L

2008-01-01

.... This Master's Thesis describes the NPS-SCAT (solar cell array tester) project, including the author's experience as program manager of the project, responsible for budget, schedule and technical deliverables...

Amide proton transfer (APT) imaging of brain tumors at 7 T : The role of tissue water T1 -Relaxation properties

NARCIS (Netherlands)

Khlebnikov, V; Polders, Daniel; Hendrikse, J; Robe, Pierre A.; Voormolen, Eduard H; Luijten, Peter R; Klomp, DWJ; Hoogduin, Hans

PURPOSE: To provide insight into the effect of water T1 relaxation (T1wat ) on amide proton transfer (APT) contrast in tumors. Three different metrics of APT contrast-magnetization transfer ratio (MTRRex ), relaxation-compensated MTRRex (AREX), and traditional asymmetry (MTRasym )-were compared in

A novel sandwich-type electrochemical aptasensor based on GR-3D Au and aptamer-AuNPs-HRP for sensitive detection of oxytetracycline.

Science.gov (United States)

Liu, Su; Wang, Yu; Xu, Wei; Leng, Xueqi; Wang, Hongzhi; Guo, Yuna; Huang, Jiadong

2017-02-15

In this paper, a novel sandwich-type electrochemical aptasensor has been fabricated and applied for sensitive and selective detection of antibiotic oxytetracycline (OTC). This sensor was based on graphene-three dimensional nanostructure gold nanocomposite (GR-3D Au) and aptamer-AuNPs-horseradish peroxidase (aptamer-AuNPs-HRP) nanoprobes as signal amplification. Firstly, GR-3D Au film was modified on glassy carbon electrode only by one-step electrochemical coreduction with graphite oxide (GO) and HAuCl 4 at cathodic potentials, which enhanced the electron transfer and loading capacity of biomolecules. Then the aptamer and HRP modified Au nanoparticles provide high affinity and ultrasensitive electrochemical probe with excellent specificity for OTC. Under the optimized conditions, the peak current was linearly proportional to the concentration of OTC in the range of 5×10 -10 -2×10 -3 gL -1 , with a detection limit of 4.98×10 -10 gL -1 . Additionally, this aptasensor had the advantages in high sensitivity, superb specificity and showed good recovery in synthetic samples. Hence, the developed sandwich-type electrochemical aptasensor might provide a useful and practical tool for OTC determination and related food safety analysis and clinical diagnosis. Copyright © 2016 Elsevier B.V. All rights reserved.

Conceptual Design of an APT Reusable Spaceplane

Science.gov (United States)

Corpino, S.; Viola, N.

This paper concerns the conceptual design of an Aerial Propellant Transfer reusable spaceplane carried out during our PhD course under the supervision of prof. Chiesa. The new conceptual design methodology employed in order to develop the APT concept and the main characteristics of the spaceplane itself will be presented and discussed. The methodology for conceptual design has been worked out during the last three years. It was originally thought for atmospheric vehicle design but, thanks to its modular structure which makes it very flexible, it has been possible to convert it to space transportation systems design by adding and/or modifying a few modules. One of the major improvements has been for example the conception and development of the mission simulation and trajectory optimisation module. The methodology includes as main characteristics and innovations the latest techniques of geometric modelling and logistic, operational and cost aspects since the first stages of the project. Computer aided design techniques are used to obtain a better definition of the product at the end of the conceptual design phase and virtual reality concepts are employed to visualise three-dimensional installation and operational aspects, at least in part replacing full-scale mock- ups. The introduction of parametric three-dimensional CAD software integrated into the conceptual design methodology represents a great improvement because it allows to carry out different layouts and to assess them immediately. It is also possible to link the CAD system to a digital prototyping software which combines 3D visualisation and assembly analysis, useful to define the so-called Digital Mock-Up at Conceptual Level (DMUCL) which studies the integration between the on board systems, sized with simulation algorithms, and the airframe. DMUCL represents a very good means to integrate the conceptual design with a methodology turned towards dealing with Reliability, Availability, Maintainability and

A novel reduced graphene oxide/molybdenum disulfide/polyaniline nanocomposite-based electrochemical aptasensor for detection of aflatoxin B1.

Science.gov (United States)

Geleta, Girma Selale; Zhao, Zhen; Wang, Zhenxin

2018-03-26

In this study, we developed a novel reduced graphene oxide/molybdenum disulfide/polyaniline@gold nanoparticles-based electrochemical aptasensor (termed as RGO/MoS2/PANI@AuNPs/Apt) for detection of aflatoxin B1 (AFB1). The RGO/MoS2/PANI nanocomposites were synthesized and characterized by multiple techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), infrared spectroscopy (FTIR), UV-visible spectroscopy, and X-ray photoelectron spectroscopy (XPS). A glassy carbon electrode (GCE) was then modified by the RGO/MoS2/PANI nanocomposites, coated with a chitosan (Cs) film, and followed by AuNPs attachment for immobilizing the AFB1 aptamers. In the presence of AFB1, the AFB1 binding-induced conformation change of the immobilized aptamer on the electrode surface results in the reduction of the electron transfer from a [Fe(CN)6]3-/4- redox couple in the solution to the GCE surface. Therefore, the aptamer-AFB1 binding event can be easily monitored by the peak current change of the RGO/MoS2/PANI@AuNPs/Apt through differential pulse voltammetry (DPV) measurement. Under the optimized conditions, the as-developed RGO/MoS2/PANI@AuNPs/Apt exhibits a wide linear range from 0.01 fg mL-1 to 1.0 fg mL-1 and a remarkably low detection limit (3σ) of 0.002 fg mL-1. The aptasensor also has good reproducibility as well as shows high selectivity against other fungal toxins, such as OTA and FB1. Moreover, the practicability of the RGO/MoS2/PANI@AuNPs/Apt was demonstrated by the analysis of AFB1 in the spiked wine samples.

Anti-prothrombin (aPT) and anti-phosphatidylserine/prothrombin (aPS/PT) antibodies and the risk of thrombosis in the antiphospholipid syndrome. A systematic review.

Science.gov (United States)

Sciascia, Savino; Sanna, Giovanni; Murru, Veronica; Roccatello, Dario; Khamashta, Munther A; Bertolaccini, Maria Laura

2014-02-01

Antibodies to prothrombin are detected by directly coating prothrombin on irradiated ELISA plates (aPT) or by using the phosphatidylserine/prothrombin complex as antigen (aPS/PT). Although these antibodies have both been associated with antiphospholipid syndrome (APS) and a correlation between the two assays have been reported, it seems that aPT and aPS/PT belong to different populations of autoantibodies. It was our objective to systematically review the available evidence on aPT and aPS/PT antibodies and the risk of thrombosis in APS. Medline-reports published between 1988 and 2013 investigating aPT and aPS/PT as a risk factor for thrombosis were included. Whenever possible, antibody isotype(s) and site of thrombosis were analysed. This systematic review is based on available data from more than 7,000 patients and controls from 38 studies analysing aPT and 10 aPS/PT. Antibodies to prothrombin (both aPT and aPS/PT) increased the risk of thrombosis (odds ratio [OR] 2.3; 95% confidence interval [CI] 1.72-3.5). aPS/PT seemed to represent a stronger risk factor for thrombosis, both arterial and/or venous than aPT (OR 5.11; 95%CI 4.2-6.3 and OR 1.82; 95%CI 1.44-2.75, respectively). In conclusion, routine measurement of aPS/PT (but not aPT) might be useful in establishing the thrombotic risk of patients with previous thrombosis and/or systemic lupus erythematosus. Their inclusion as laboratory criteria for the APS should be indisputably further explored.

Study of different 3-aminopropyl triethoxysilane (APTES) concentration on TiO2 particles based IDE for cervical cancer detection

Science.gov (United States)

Raqeema, S.; Hashim, U.; Azizah, N.; Nadzirah, Sh.; Arshad, M. K. Md; Ruslinda, A. R.; Gopinath, Subash C. B.

2017-03-01

HPV that also called Human Papillomaviruses is the major cause of the cervical cancer. HPV 16 and HPV 18 are the two types of HPV are the most HPV-associated cancers and responsible as a high-risk HPV. Cervical cancer taken about 70 percent of all cases due HPV infections. Cervical malignancy for the most part development on a lady's cervix and its was developed slowly as cancer disease. TiO2 particles give better performance and low cost of the biosensor. The used of 3-aminopropyl triethoxysilane (APTES) will be more efficient for DNA nanochip. APTES used as absorption reaction to immobilize organic biomolecules on the inorganic surface. Besides, APTES give better functionalization of the adsorption mechanism on IDE. The surface functionalized for immobilizing the DNA, which is the combination of the DNA probe and the HPV target produce high sensitivity andfast detection of the IDE. The Current-Voltage (IV) characteristic proved the sensitivity of the DNA nanochip increase as the concentration varied from 0% concentration to 24% of APTES concentration.

Hierarchically Structured Recommender System for Improving NPS

Science.gov (United States)

Kuang, Jieyan

2016-01-01

Net Promoter System (NPS) is well known as an evaluation measure of the growth engine of big companies in the business area. The ultimate goal of my research is to build an action rules and meta-actions based recommender system for improving NPS scores of 34 companies (clients) dealing with similar businesses in the US and Canada. With the given…

Development of a commissioning plan for the APT linac

International Nuclear Information System (INIS)

Funk, L.W.; Crandall, K.R.; Gilpatrick, J.D.; Gray, E.R.; Regan, A.H.; Rohlev, A.; Rybarcyk, L.J.; Wangler, T.P.

1998-01-01

The Accelerator Production of Tritium (APT) facility is based on a linac which incorporates both normal-conducting and superconducting RF technology and accelerates a 100-mA cw proton beam to an energy of 1,030 MeV or higher, depending on the desired production rate. Commissioning plans to achieve full power operation with minimum beam-induced activation of components have been evolving. This paper presents the main issues and the basic approaches that are now being discussed

Hydroxycamptothecin-loaded nanoparticles enhance target drug delivery and anticancer effect

Directory of Open Access Journals (Sweden)

Li Su

2008-05-01

Full Text Available Abstract Background Hydroxycamptothecin (HCPT has been shown to have activity against a broad spectrum of cancers. In order to enhance its tissue-specific delivery and anticancer activity, we prepared HCPT-loaded nanoparticles made from poly(ethylene glycol-poly(γ-benzyl-L-glutamate (PEG-PBLG, and then studied their release characteristics, pharmacokinetic characteristics, and anticancer effects. PEG-PBLG nanoparticles incorporating HCPT were prepared by a dialysis method. Scanning electron microscopy (SEM was used to observe the shape and diameter of the nanoparticles. The HCPT release characteristics in vitro were evaluated by ultraviolet spectrophotometry. A high-performance liquid chromatography (HPLC detection method for determining HCPT in rabbit plasma was established. The pharmacokinetic parameters of HCPT/PEG-PBLG nanoparticles were compared with those of HCPT. Results The HCPT-loaded nanoparticles had a core-shell spherical structure, with a core diameter of 200 nm and a shell thickness of 30 nm. Drug-loading capacity and drug encapsulation were 7.5 and 56.8%, respectively. The HCPT release profile was biphasic, with an initial abrupt release, followed by sustained release. The terminal elimination half-lives (t 1/2 β of HCPT and HCPT-loaded nanoparticles were 4.5 and 10.1 h, respectively. Peak concentrations (Cmax of HCPT and HCPT-loaded nanoparticles were 2627.8 and 1513.5 μg/L, respectively. The apparent volumes of distribution of the HCPT and HCPT-loaded nanoparticles were 7.3 and 20.0 L, respectively. Compared with a blank control group, Lovo cell xenografts or Tca8113 cell xenografts in HCPT or HCPT-loaded nanoparticle treated groups grew more slowly and the tumor doubling times were increased. The tumor inhibition effect in the HCPT-loaded nanosphere-treated group was significantly higher than that of the HCPT-treated group (p 0.05. Conclusion Compared to the HCPT- and control-treated groups, the HCPT-loaded nanoparticle

Hierarchical self-assembly of magnetic nanoclusters for theranostics: Tunable size, enhanced magnetic resonance imagability, and controlled and targeted drug delivery.

Science.gov (United States)

Nguyen, Dai Hai; Lee, Jung Seok; Choi, Jong Hoon; Park, Kyung Min; Lee, Yunki; Park, Ki Dong

2016-04-15

Nanoparticle-based imaging and therapy are of interest for theranostic nanomedicine. In particular, superparamagnetic iron oxide (SPIO) nanoparticles (NPs) have attracted much attention in cancer imaging, diagnostics, and treatment because of their superior imagability and biocompatibility (approved by the Food and Drug Administration). Here, we developed SPIO nanoparticles (NPs) that self-assembled into magnetic nanoclusters (SAMNs) in aqueous environments as a theranostic nano-system. To generate multi-functional SPIO NPs, we covalently conjugated β-cyclodextrin (β-CD) to SPIO NPs using metal-adhesive dopamine groups. Polyethylene glycol (PEG) and paclitaxel (PTX) were hosted in the β-CD cavity through high affinity complexation. The core-shell structure of the magnetic nanoclusters was elucidated based on the condensed SPIO core and a PEG shell using electron microscopy and the composition was analyzed by thermogravimetric analysis (TGA). Our results indicate that nanocluster size could be readily controlled by changing the SPIO/PEG ratio in the assemblies. Interestingly, we observed a significant enhancement in magnetic resonance contrast due to the large cluster size and dense iron oxide core. In addition, tethering a tumor-targeting peptide to the SAMNs enhanced their uptake into tumor cells. PTX was efficiently loaded into β-CDs and released in a controlled manner when exposed to competitive guest molecules. These results strongly indicate that the SAMNs developed in this study possess great potential for application in image-guided cancer chemotherapy. In this study, we developed multi-functional SPIO NPs that self-assembled into magnetic nanoclusters (SAMNs) in aqueous conditions as a theranostic nano-system. The beta-cyclodextrin (β-CD) was immobilized on the surfaces of SPIO NPs and RGD-conjugated polyethylene glycol (PEG) and paclitaxel (PTX) were hosted in the β-CD cavity through high affinity complexation. We found that nanocluster size could be

The utilization of SiNWs/AuNPs-modified indium tin oxide (ITO) in fabrication of electrochemical DNA sensor

Energy Technology Data Exchange (ETDEWEB)

Rashid, Jahwarhar Izuan Abdul [Institute of Advanced Technology, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia); Department of Chemistry and Biology, Centre for Defense Foundation Studies, National Defense University of Malaysia, Sungai Besi Camp, 57000 Kuala Lumpur (Malaysia); Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia); Yusof, Nor Azah, E-mail: azahy@upm.edu.my [Institute of Advanced Technology, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia); Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia); Abdullah, Jaafar [Institute of Advanced Technology, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia); Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia); Hashim, Uda [Institute of Nanoelectronic Engineering, Universiti Malaysia Perlis, 01000 Kangar, Perlis (Malaysia); Hajian, Reza, E-mail: rezahajian@upm.edu.my [Institute of Advanced Technology, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia)

2014-12-01

This work describes the incorporation of SiNWs/AuNPs composite as a sensing material for DNA detection on indium tin-oxide (ITO) coated glass slide. The morphology of SiNWs/AuNPs composite as the modifier layer on ITO was studied by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The morphological studies clearly showed that SiNWs were successfully decorated with 20 nm-AuNPs using self-assembly monolayer (SAM) technique. The effective surface area for SiNWs/AuNPs-modified ITO enhanced about 10 times compared with bare ITO electrode. SiNWs/AuNPs nanocomposite was further explored as a matrix for DNA probe immobilization in detection of dengue virus as a bio-sensing model to evaluate its performance in electrochemical sensors. The hybridization of complementary DNA was monitored by differential pulse voltammetry (DPV) using methylene blue (MB) as the redox indicator. The fabricated biosensor was able to discriminate significantly complementary, non-complementary and single-base mismatch oligonucleotides. The electrochemical biosensor was sensitive to target DNA related to dengue virus in the range of 9.0–178.0 ng/ml with detection limit of 3.5 ng/ml. In addition, SiNWs/AuNPs-modified ITO, regenerated up to 8 times and its stability was up to 10 weeks at 4 °C in silica gel. - Highlights: • A sensitive biosensor is presented for detection of dengue virus. • SiNWs and AuNPs used as nanocomposite layers on ITO for construction of biosensor • The detection mechanism is based on the interaction of MB with DNA bonded on AuNPs. • The reduction signal of MB decreases upon complementary hybridization.

The utilization of SiNWs/AuNPs-modified indium tin oxide (ITO) in fabrication of electrochemical DNA sensor

International Nuclear Information System (INIS)

Rashid, Jahwarhar Izuan Abdul; Yusof, Nor Azah; Abdullah, Jaafar; Hashim, Uda; Hajian, Reza

2014-01-01

This work describes the incorporation of SiNWs/AuNPs composite as a sensing material for DNA detection on indium tin-oxide (ITO) coated glass slide. The morphology of SiNWs/AuNPs composite as the modifier layer on ITO was studied by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The morphological studies clearly showed that SiNWs were successfully decorated with 20 nm-AuNPs using self-assembly monolayer (SAM) technique. The effective surface area for SiNWs/AuNPs-modified ITO enhanced about 10 times compared with bare ITO electrode. SiNWs/AuNPs nanocomposite was further explored as a matrix for DNA probe immobilization in detection of dengue virus as a bio-sensing model to evaluate its performance in electrochemical sensors. The hybridization of complementary DNA was monitored by differential pulse voltammetry (DPV) using methylene blue (MB) as the redox indicator. The fabricated biosensor was able to discriminate significantly complementary, non-complementary and single-base mismatch oligonucleotides. The electrochemical biosensor was sensitive to target DNA related to dengue virus in the range of 9.0–178.0 ng/ml with detection limit of 3.5 ng/ml. In addition, SiNWs/AuNPs-modified ITO, regenerated up to 8 times and its stability was up to 10 weeks at 4 °C in silica gel. - Highlights: • A sensitive biosensor is presented for detection of dengue virus. • SiNWs and AuNPs used as nanocomposite layers on ITO for construction of biosensor • The detection mechanism is based on the interaction of MB with DNA bonded on AuNPs. • The reduction signal of MB decreases upon complementary hybridization

The utilization of SiNWs/AuNPs-modified indium tin oxide (ITO) in fabrication of electrochemical DNA sensor.

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Rashid, Jahwarhar Izuan Abdul; Yusof, Nor Azah; Abdullah, Jaafar; Hashim, Uda; Hajian, Reza

2014-12-01

This work describes the incorporation of SiNWs/AuNPs composite as a sensing material for DNA detection on indium tin-oxide (ITO) coated glass slide. The morphology of SiNWs/AuNPs composite as the modifier layer on ITO was studied by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The morphological studies clearly showed that SiNWs were successfully decorated with 20 nm-AuNPs using self-assembly monolayer (SAM) technique. The effective surface area for SiNWs/AuNPs-modified ITO enhanced about 10 times compared with bare ITO electrode. SiNWs/AuNPs nanocomposite was further explored as a matrix for DNA probe immobilization in detection of dengue virus as a bio-sensing model to evaluate its performance in electrochemical sensors. The hybridization of complementary DNA was monitored by differential pulse voltammetry (DPV) using methylene blue (MB) as the redox indicator. The fabricated biosensor was able to discriminate significantly complementary, non-complementary and single-base mismatch oligonucleotides. The electrochemical biosensor was sensitive to target DNA related to dengue virus in the range of 9.0-178.0 ng/ml with detection limit of 3.5 ng/ml. In addition, SiNWs/AuNPs-modified ITO, regenerated up to 8 times and its stability was up to 10 weeks at 4°C in silica gel. Copyright © 2014 Elsevier B.V. All rights reserved.

Dorzolamide-loaded PLGA/vitamin E TPGS nanoparticles for glaucoma therapy: Pharmacoscintigraphy study and evaluation of extended ocular hypotensive effect in rabbits.

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Warsi, Musarrat H; Anwar, Mohammed; Garg, Vaidehi; Jain, Gaurav K; Talegaonkar, Sushama; Ahmad, Farhan J; Khar, Roop K

2014-10-01

Poor drug penetration and rapid clearance after topical instillation of a drug formulation into the eyes are the major causes for the lower ocular bioavailability from conventional eye drops. Along with this, poor encapsulation efficiency of hydrophilic drug in polymeric nanoparticles remains a major formulation challenge. Taking this perspective into consideration, dorzolamide (DZ)-loaded PLGA nanoparticles were developed employing two different emulsifiers (PVA and vitamin E TPGS) and the effects of various formulation and process variables on particle size and encapsulation efficiency were assessed. Nanoparticles emulsified with vitamin E TPGS (DZ-T-NPs) were found to possess enhanced drug encapsulation (59.8±6.1%) as compared to those developed with PVA as emulsifier (DZ-P-NPs). Transcorneal permeation study revealed a significant enhancement in permeation (1.8-2.5 fold) as compared to solution. In addition, ex vivo biodistribution study showed a higher concentration of drug in the aqueous humour (1.5-2.3 fold). Histological and IR-camera studies proved the non-irritant potential of the formulations. Pharmacoscintigraphic studies revealed the reduced corneal clearance, as well as naso-lachrymal drainage in comparison to drug solution. Furthermore, efficacy study revealed that DZ-P-NPs and DZ-T-NPs significantly reduced the intraocular pressure by 22.81% and 29.12%, respectively, after a single topical instillation into the eye. Copyright © 2014 Elsevier B.V. All rights reserved.

NPS Adds Another Astronaut Alumnus With NASA’s Newest Class

OpenAIRE

Kuska, Dale M.

2013-01-01

Article taken from the NPS website: http://www.nps.edu/About/News/NPS-Adds-Another-Astronaut-Alumnus-With-NASAs-Newest-Class.html When NASA Administrator Charles Bolden announced the latest class of NASA’s eight astronaut candidates, June 17, the Naval Postgraduate School (NPS) was able to add yet another space-traveling alumnus to its ranks, now totaling 41 and counting. Lt. Cmdr. Victor Glover, an F/A-18 combat pilot currently serving as a Legislative Fellow in the office of Senat...

Comparative Study of Antimicrobial Activity of AgBr and Ag Nanoparticles (NPs)

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Suchomel, Petr; Kvitek, Libor; Panacek, Ales; Prucek, Robert; Hrbac, Jan; Vecerova, Renata; Zboril, Radek

2015-01-01

The diverse mechanism of antimicrobial activity of Ag and AgBr nanoparticles against gram-positive and gram-negative bacteria and also against several strains of candida was explored in this study. The AgBr nanoparticles (NPs) were prepared by simple precipitation of silver nitrate by potassium bromide in the presence of stabilizing polymers. The used polymers (PEG, PVP, PVA, and HEC) influence significantly the size of the prepared AgBr NPs dependently on the mode of interaction of polymer with Ag+ ions. Small NPs (diameter of about 60–70 nm) were formed in the presence of the polymer with low interaction as are PEG and HEC, the polymers which interact with Ag+ strongly produce nearly two times bigger NPs (120–130 nm). The prepared AgBr NPs were transformed to Ag NPs by the reduction using NaBH4. The sizes of the produced Ag NPs followed the same trends – the smallest NPs were produced in the presence of PEG and HEC polymers. Prepared AgBr and Ag NPs dispersions were tested for their biological activity. The obtained results of antimicrobial activity of AgBr and Ag NPs are discussed in terms of possible mechanism of the action of these NPs against tested microbial strains. The AgBr NPs are more effective against gram-negative bacteria and tested yeast strains while Ag NPs show the best antibacterial action against gram-positive bacteria strains. PMID:25781988

Enhanced local bioavailability of single or compound drugs delivery to the inner ear through application of PLGA nanoparticles via round window administration.

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Cai, Hui; Wen, Xingxing; Wen, Lu; Tirelli, Nicola; Zhang, Xiao; Zhang, Yue; Su, Huanpeng; Yang, Fan; Chen, Gang

2014-01-01

In this paper, the potential of poly(D,L-lactide-co-glycolide acid) (PLGA) nanoparticles (NPs) for carrying single or compound drugs traversing the round window membrane (RWM) was examined after the round window (RW) administration of different NPs to guinea pigs. First, coumarin-6 was incorporated into PLGA NPs as a fluorescent probe to investigate its ability to cross the RWM. Then, PLGA NPs with salvianolic acid B (Sal B), tanshinone IIA (TS IIA), and total panax notoginsenoside (PNS) including notoginsenoside R1 (R1), ginsenoside Rg1 (Rg1), and ginsenoside Rb1 (Rb1) were developed to evaluate whether NPs loaded with compound drugs would pass through the RWM and improve the local bioavailability of these agents. PLGA NPs loaded with single or compound drugs were prepared by the emulsification solvent evaporation method, and their particle size distribution, particle morphology, and encapsulation efficiency were characterized. In vitro release study showed sustained-release profiles of Sal B, TS IIA, and PNS from the NPs. The pharmacokinetic results showed that NPs applied to the RWM significantly improved drug distribution within the inner ear. The AUC0-t of coumarin-6 in the perilymph (PL) following RW administration of NPs was 4.7-fold higher than that of coumarin-6 solution, and the Cmax was 10.9-fold higher. Furthermore, the AUC(0-t) of R1, Rg1, and Rb1 were 4.0-, 3.1-, and 7.1-fold greater, respectively, after the application of NPs compared to the compound solution, and the Cmax were, respectively, 14.4-, 10.0-, and 16.7-fold higher. These findings suggest that PLGA NPs with unique properties at the nanoscale dimensions have a powerful ability to transport single or compound drugs into the PL through the RWM and remarkably enhance the local bioavailability of the encapsulated drugs in the inner ear. The use of PLGA NPs as nanoscale delivery vehicles to carry drugs across the RWM may be a promising strategy for the treatment of inner ear diseases.

Novel Psychoactive Substances (NPS): a Study on Persian Language Websites.

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Bigdeli, Imanollah; Corazza, Ornella; Aslanpour, Zoe; Schifano, Fabrizio

2013-01-01

During the past few years, there has been an increasing recognition that Internet is playing a significant role in the synthesis, the distribution and the consumption of Novel Psychoactive Substances (NPS).The aim of this study was to assess the online availability of NPS in Persian language websites. The Google search engine was used to carry out an accurate qualitative assessment of information available on NPS in a sample of 104 websites. The monitoring has led to the identification of 14 NPS including herbal, synthetic, pharmaceutical and combination drugs that have been sold online. The availability of online marketing of NPS in Persian language websites may constitute a public health challenge at least across three Farsi-speaking countries in the Middle East. Hence, descriptions of this phenomenon are valuable to clinicians and health professional in this region. Further international collaborative efforts may be able to tackle the growth and expansion of regular offer of NPS.

Size control of Au NPs supported by pH operation

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Ichiji, Masumi; Akiba, Hiroko; Hirasawa, Izumi

2017-07-01

Au NPs are expected to become useful functional particles, as particle gun used for plant gene transfer and also catalysts. We have studied PSD (particle size distribution) control of Au NPs by reduction crystallization. Previous study found out importance of seeds policy and also feeding profile. In this paper, effect of pH in the reduction crystallization was investigated to clarify the possibility of Au NPs PSD control by pH operation and also their growth process. Au NPs of size range 10-600 nm were obtained in single-jet system using ascorbic acid (AsA) as a reducing agent with adjusting pH of AsA. Au NPs are found to grow in the process of nucleation, agglomeration, agglomeration growth and surface growth. Au NPs tend to grow by agglomeration and become larger size in lower pH regions, and to grow only by surface growth and become smaller size in higher pH regions.

Is Accelerated Partner Therapy (APT) a cost-effective alternative to routine patient referral partner notification in the UK? Preliminary cost-consequence analysis of an exploratory trial.

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Roberts, Tracy E; Tsourapas, Angelos; Sutcliffe, Lorna; Cassell, Jackie; Estcourt, Claudia

2012-02-01

To undertake a cost-consequence analysis to assess two new models of partner notification (PN), known as Accelerated Partner Therapy (APT Hotline and APT Pharmacy), as compared with routine patient referral PN, for sex partners of people with chlamydia, gonorrhoea and non-gonococcal urethritis. Comparison of costs and outcomes alongside an exploratory trial involving two genitourinary medicine clinics and six community pharmacies. Index patients selected the PN method (APT Hotline, APT Pharmacy or routine PN) for their partners. Clinics and pharmacies recorded cost and resource use data including duration of consultation and uptake of treatment pack. Cost data were collected prospectively for two out of three interventions, and data were synthesised and compared in terms of effectiveness and costs. Routine PN had the lowest average cost per partner treated (approximately £46) compared with either APT Hotline (approximately £54) or APT Pharmacy (approximately £53) strategies. The cost-consequence analysis revealed that APT strategies were more costly but also more effective at treating partners compared to routine PN. The hotline strategy costs more than both the alternative PN strategies. If we accept that strategies which identify and treat partners the fastest are likely to be the most effective in reducing reinfection and onward transmission, then APT Hotline appears an effective PN strategy by treating the highest number of partners in the shortest duration. Whether the additional benefit is worth the additional cost cannot be determined in this preliminary analysis. These data will be useful for informing development of future randomised controlled trials of APT.

iRGD-modified lipid–polymer hybrid nanoparticles loaded with isoliquiritigenin to enhance anti-breast cancer effect and tumor-targeting ability

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Gao F

2017-06-01

Full Text Available Fei Gao,1–3 Jinming Zhang,3 Chaomei Fu,3 Xiaoming Xie,4 Fu Peng,1–3 Jieshu You,1,2 Hailin Tang,1,2,4 Zhiyu Wang,5 Peng Li,6 Jianping Chen1–3 1School of Chinese Medicine, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, 2Shenzhen Institute of Research and Innovation, University of Hong Kong, Shenzhen, 3College of Pharmacy, Chengdu University of Chinese Medicine, Chengdu, 4Department of Breast Oncology, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, 5Department of Mammary Disease, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, 6State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macau, People’s Republic of China Abstract: Isoliquiritigenin (ISL, a natural anti-breast cancer dietary compound, has poor delivery characteristics and low bioavailability. In order to promote the therapeutic outcome of ISL, a tumor-targeting lipid–polymer hybrid nanoparticle (NP system modified by tumor-homing iRGD peptides has been developed. The hybrid NPs were prepared by a modified single-step nanoprecipitation method to encapsulate ISL. iRGD peptides were anchored on the surface by a postinsertion method (ISL-iRGD NPs. The stable lipid–polymer structure of ISL-iRGD NPs, with high encapsulation and loading efficiency, was confirmed. Compared to free ISL and non-iRGD-modified counterparts, ISL-iRGD NPs showed higher cytotoxicity and cell apoptosis against the different type of breast cancer cells. This was attributable to higher cellular accumulation mediated by the iRGD-integrin recognition and the nanoscale effect. More importantly, based on the active tumor-tissue accumulation by iRGD peptides and the prolonged in vivo circulation by the stealth nanostructure, ISL-iRGD NPs displayed higher tumor-growth inhibition efficiency in 4T1-bearing breast-tumor mouse

Paclitaxel-loaded poly(glycolide-co-ε-caprolactone-b-D-α-tocopheryl polyethylene glycol 2000 succinate nanoparticles for lung cancer therapy

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Zhao TJ

2013-05-01

Full Text Available Tiejun Zhao,1 Hezhong Chen,1 Yuchao Dong,2 Jiajun Zhang,1 Haidong Huang,2 Ji Zhu,1 Wei Zhang21Institute of Cardiothoracic Surgery, 2Respiratory Department, Changhai Hospital, Shanghai, People's Republic of ChinaAbstract: In order to improve the therapeutic efficacy and minimize the side effects of lung cancer chemotherapy, the formulation of paclitaxel-loaded poly(glycolide-co-ε-caprolactone-b-D-α-tocopheryl polyethylene glycol 2000 succinate nanoparticles (PTX-loaded [PGA-co-PCL]-b-TPGS2k NPs was prepared. The novel amphiphilic copolymer (PGA-co-PCL-b-TPGS2k was synthesized by ring-opening polymerization and characterized by proton nuclear magnetic resonance spectroscopy and gel permeation chromatography. The PTX-loaded (PGA-co-PCL-b -TPGS2k NPs were characterized in terms of size, size distribution, zeta potential, drug encapsulation, surface morphology, and drug release. In vitro cellular uptakes of NPs were investigated with confocal laser scanning microscopy, indicating the coumarin 6-loaded (PGA-co-PCL-b -TPGS2k NPs could be internalized by human lung cancer A-549 cells. The antitumor effect of PTX-loaded NPs was evaluated, both in vitro and in vivo, on an A-549 cell tumor-bearing mouse model via intratumoral injection. The commercial PTX formulation Taxol was chosen as the reference. Experimental results showed that the PTX-loaded NPs possessed higher cytotoxicity and could effectively inhibit the growth of tumor. All the results suggested that amphiphilic copolymer (PGA-co-PCL-b -TPGS2k could act as a potential biological material for nanoformulation in the treatment of lung cancer.Keywords: (PGA-co-PCL-b TPGS2k, paclitaxel, nanoparticles, drug delivery, lung cancer

Oridonin Loaded Solid Lipid Nanoparticles Enhanced Antitumor Activity in MCF-7 Cells

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Lu Wang

2014-01-01

Full Text Available Oridonin (ORI, a famous diterpenoid from Chinese herbal medicine, has drawn rising attention for its remarkable apoptosis and autophagy-inducing activity in human cancer therapy, while clinical application of ORI is limited by its strong hydrophobicity and rapid plasma clearance. The purpose of this study was to evaluate whether the antitumor activity of ORI could be enhanced by loading into solid lipid nanoparticles (SLNs. ORI-loaded SLNs were prepared by hot high pressure homogenization with narrow size distribution and good entrapment efficacy. MTT assay indicated that ORI-loaded SLNs enhanced the inhibition of proliferation against several human cancer cell lines including breast cancer MCF-7 cells, hepatocellular carcinoma HepG 2 cells, and lung carcinoma A549 cells compared with free ORI, while no significant enhancement of toxicity to human mammary epithelial MCF-10A cells was shown. Meanwhile, flow cytometric analysis demonstrated that ORI-SLNs induced more significant cell cycle arrest at S and decreased cell cycle arrest at G1/G0 phase in MCF-7 cells than bulk ORI solution. Hoechst 33342 staining and Annexin V/PI assay indicated that apoptotic rates of cells treated with ORI-loaded SLNs were higher compared with free ORI. In summary, our data indicated that SLNs may be a potential carrier for enhancing the antitumor effect of hydrophobic drug ORI.

Can we improve partner notification rates through expedited partner therapy in the UK? Findings from an exploratory trial of Accelerated Partner Therapy (APT).

Science.gov (United States)

Estcourt, Claudia; Sutcliffe, Lorna; Cassell, Jackie; Mercer, Catherine H; Copas, Andrew; James, Laura; Low, Nicola; Horner, Patrick; Clarke, Michael; Symonds, Merle; Roberts, Tracy; Tsourapas, Angelos; Johnson, Anne M

2012-02-01

To develop two new models of expedited partner therapy for the UK, and evaluate them for feasibility, acceptability and preliminary outcome estimates to inform the design of a randomised controlled trial (RCT). Two models of expedited partner therapy (APTHotline and APTPharmacy), known as 'Accelerated Partner Therapy' (APT) were developed. A non-randomised comparative study was conducted of the two APT models and routine partner notification (PN), in which the index patient chose the PN option for his/her partner(s) in two contrasting clinics. The proportion of contactable partners treated when routine PN was chosen was 42/117 (36%) and was significantly higher if either APT option was chosen: APTHotline 80/135 (59%), p=0.003; APTPharmacy 29/44 (66%) p=0.001. However, partner treatment was often achieved through other routes. Although 40-60% of partners in APT groups returned urine samples for sexually transmitted infection (STI) testing, almost none accessed HIV and syphilis testing. APT options appear to facilitate faster treatment of sex partners than routine PN. Preferences and recruitment rates varied between sites, related to staff satisfaction with existing routine PN; approach to consent; and possibly, characteristics of local populations. Both methods of APT were feasible and acceptable to many patients and led to higher rates of partner treatment than routine PN. Preferences and recruitment rates varied greatly between settings, suggesting that organisational and cultural factors may have an important impact on the feasibility of an RCT and on outcomes. Mindful of these factors, it is proposed that APT should now be evaluated in a cluster RCT.

The Growing Problem of New Psychoactive Substances (NPS).

Science.gov (United States)

Madras, Bertha K

The term "new psychoactive substances" (NPS) can be defined as individual drugs in pure form or in complex preparations that are not scheduled under the Single Convention on Narcotic Drugs (1961) or the Convention on Psychotropic Substances (1971). NPS may be categorized by chemical structure, by psychoactive properties, by biological targets, or by source (plant, synthetic, or combined). The emergence of hundreds of NPS in the past decade is challenging for public health and drug policies globally. The novelty of NPS, their ambiguous legal status, ability to evade toxicological tests, swift adaptation to legal restrictions, global Internet marketing, and scant public knowledge of their adverse effects are among the key drivers of this twenty-first century phenomenon. Multi-disciplinary research in areas of biology, epidemiology, prevention, and web analytics are needed to develop effective responses in a domain capable of overwhelming current international conventions and national drug control policies. Ultimately, research-guided prevention education will fortify societies against this tidal wave.

Shock enhancement of cellular materials subjected to intensive pulse loading

Science.gov (United States)

Zhang, J.; Fan, J.; Wang, Z.; Zhao, L.; Li, Z.

2018-03-01

Cellular materials can dissipate a large amount of energy due to their considerable stress plateau, which contributes to their extensive applications in structural design for crashworthiness. However, in some experiments with specimens subjected to intense impact loads, transmitted stress enhancement has been observed, leading to severe damage to the objects protected. Transmitted stress through two-dimensional Voronoi cellular materials as a protective device is qualitatively studied in this paper. Dimensionless parameters of material properties and loading parameters are defined to give critical conditions for shock enhancement and clarify the correlation between the deformations and stress enhancement. The effect of relative density on this amplifying phenomenon is investigated as well. In addition, local strain fields are calculated by using the optimal local deformation gradient, which gives a clear presentation of deformations and possible local non-uniformity in the crushing process. This research provides valuable insight into the reliability of cellular materials as protective structures.

Pigment epithelial-derived factor gene loaded novel COOH-PEG-PLGA-COOH nanoparticles promoted tumor suppression by systemic administration.

Science.gov (United States)

Yu, Ting; Xu, Bei; He, Lili; Xia, Shan; Chen, Yan; Zeng, Jun; Liu, Yongmei; Li, Shuangzhi; Tan, Xiaoyue; Ren, Ke; Yao, Shaohua; Song, Xiangrong

2016-01-01

Anti-angiogenesis has been proposed as an effective therapeutic strategy for cancer treatment. Pigment epithelium-derived factor (PEDF) is one of the most powerful endogenous anti-angiogenic reagents discovered to date and PEDF gene therapy has been recognized as a promising treatment option for various tumors. There is an urgent need to develop a safe and valid vector for its systemic delivery. Herein, a novel gene delivery system based on the newly synthesized copolymer COOH-PEG-PLGA-COOH (CPPC) was developed in this study, which was probably capable of overcoming the disadvantages of viral vectors and cationic lipids/polymers-based nonviral carriers. PEDF gene loaded CPPC nanoparticles (D-NPs) were fabricated by a modified double-emulsion water-in-oil-in-water (W/O/W) solvent evaporation method. D-NPs with uniform spherical shape had relatively high drug loading (~1.6%), probably because the introduced carboxyl group in poly (D,L-lactide-co-glycolide) terminal enhanced the interaction of copolymer with the PEDF gene complexes. An excellent in vitro antitumor effect was found in both C26 and A549 cells treated by D-NPs, in which PEDF levels were dramatically elevated due to the successful transfection of PEDF gene. D-NPs also showed a strong inhibitory effect on proliferation of human umbilical vein endothelial cells in vitro and inhibited the tumor-induced angiogenesis in vivo by an alginate-encapsulated tumor cell assay. Further in vivo antitumor investigation, carried out in a C26 subcutaneous tumor model by intravenous injection, demonstrated that D-NPs could achieve a significant antitumor activity with sharply reduced microvessel density and significantly promoted tumor cell apoptosis. Additionally, the in vitro hemolysis analysis and in vivo serological and biochemical analysis revealed that D-NPs had no obvious toxicity. All the data indicated that the novel CPPC nanoparticles were ideal vectors for the systemic delivery of PEDF gene and might be widely

Fluorescence enhancement of modified silver nanoparticles.

Science.gov (United States)

Liu, Meicen; Zhang, Zhenglong; Liu, Gaining; Dong, Jun; Sun, Yu; Zheng, Hairong; Li, Guian

2011-11-01

Surface enhanced fluorescence (SEF) effect of acridine orange fluorophore in the proximity of silver nanoparticles (NPs) has been investigated experimentally in the aqueous solution system. It was found that the SEF effect could be influenced by the distribution of the NPs and the separation between the fluorophore molecule and metal surface. The fluorescence enhancement was improved significantly when Ag NPs was capped with 4-Aminothiophenol (PATP) that was acted as an isolating layer between the metal surface and fluorophore molecules. The results suggest that a proper distribution of metallic NPs and proper separation between fluorophore molecule and the particle surface are important for obtaining an optimal SEF effect.

Layer-by-layer nanoparticles co-loading gemcitabine and platinum (IV prodrugs for synergistic combination therapy of lung cancer

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Zhang R

2017-09-01

Full Text Available Rongrong Zhang, Yun Ru, Yiping Gao, Jinyin Li, Shilong Mao Department of Pharmacy, Shanghai Xuhui District Central Hospital, Zhongshan Hospital Affiliated to Fudan University Xuhui Hospital, Shanghai, People’s Republic of China Purpose: Cisplatin plus gemcitabine (GEM is a standard regimen for the first-line treatment of advanced non-small cell lung cancer. The aim of this study was to prepare biocompatible and biodegradable polymeric prodrugs and construct nanoparticles (NPs with layer-by-layer (LbL technique. Methods: Platinum (Pt (IV complex with a carboxyl group was conjugated to the amino group of chitosan (CH, resulting in a CH-Pt conjugation with positive charge. GEM with amino group was conjugated to the carboxyl group of hyaluronic acid (HA, resulting in a HA-GEM conjugation with negative charge. Novel LbL NPs consisting of the CH-Pt core and the HA-GEM layer, named as HA-GEM/CH-Pt NPs, were constructed. The physicochemical properties of the HA-GEM/CH-Pt NPs were investigated. In vitro cytotoxicity against human non-small lung cancer cells (NCl-H460 cells was investigated, and in vivo antitumor efficiency was evaluated on mice bearing NCl-H460 cells xenografts. Results: HA-GEM/CH-Pt NPs have a size of about 187 nm, a zeta potential value of -21 mV and high drug encapsulation efficiency of 90%. The drug release of HA-GEM/CH-Pt NPs exhibited a sustained behavior. HA-GEM/CH-Pt NPs could significantly enhance in vitro cytotoxicity and in vivo antitumor effect against lung cancer animal model compared to the single-drug-loaded NPs and free drug solutions. Conclusion: The results demonstrated that the HA-GEM/CH-Pt NPs might be a promising system for the synergetic treatment of lung carcinoma. Keywords: lung cancer, combination chemotherapy, cisplatin, gemcitabine, layer-by-layer technology

Silver nanoparticles (AgNPs) as a contrast agent for imaging of animal tissue using swept-source optical coherence tomography (SSOCT)

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Mondal, Indranil; Raj, Shipra; Roy, Poulomi; Poddar, Raju

2018-01-01

We present noninvasive three-dimensional depth-resolved imaging of animal tissue with a swept-source optical coherence tomography system at 1064 nm center wavelength and silver nanoparticles (AgNPs) as a potential contrast agent. A swept-source laser light source is used to enable an imaging rate of 100 kHz (100 000 A-scans s-1). Swept-source optical coherence tomography is a new variant of the optical coherence tomography (OCT) technique, offering unique advantages in terms of sensitivity, reduction of motion artifacts, etc. To enhance the contrast of an OCT image, AgNPs are utilized as an exogeneous contrast agent. AgNPs are synthesized using a modified Tollens method and characterization is done by UV-vis spectroscopy, dynamic light scattering, scanning electron microscopy and energy dispersive x-ray spectroscopy. In vitro imaging of chicken breast tissue, with and without the application of AgNPs, is performed. The effect of AgNPs is studied with different exposure times. A mathematical model is also built to calculate changes in the local scattering coefficient of tissue from OCT images. A quantitative estimation of scattering coefficient and contrast is performed for tissues with and without application of AgNPs. Significant improvement in contrast and increase in scattering coefficient with time is observed.

Influence of particle coating and matrix constituents on the cloud point extraction efficiency of silver nanoparticles (Ag-NPs) and application for monitoring the formation of Ag-NPs from Ag(+).

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Hartmann, Georg; Baumgartner, Tanja; Schuster, Michael

2014-01-07

For the quantification of silver nanoparticles (Ag-NPs) in environmental samples using cloud point extraction (CPE) for selective enrichment, surface modification of the Ag-NPs and matrix effects can play a key role. In this work we validate CPE with respect to the influence of different coatings and naturally occurring matrix components. The Ag-NPs tested were functionalized with inorganic and organic compounds as well as with biomolecules. Commercially available NPs and NPs synthesized according to methods published in the literature were used. We found that CPE can extract almost all Ag-NPs tested with very good efficiencies (82-105%). Only Ag-NPs functionalized with BSA (bovine serum albumin), which is a protein with the function to keep colloids in solution, cannot be extracted. No or little effect of environmentally relevant salts, organic matter, and inorganic colloids on the CPE of AgNPs was found. Additionally we used CPE to observe the in situ formation of Ag-NPs produced by the reduction of Ag(+) with natural organic matter (NOM).

Development of the SCRF Power Coupler for the APT Accelerator

Energy Technology Data Exchange (ETDEWEB)

Schmierer, E.N.; Lujan, R.E.; Rusnak, B.; Smith, B.; Haynes, W.B.; Gautier, C.; Waynert, J.A.; Krawczyk, F.; Gioia, J.

1999-03-01

The team responsible for the design of the Accelerator Production of Tritium (APT) superconducting (SC) radio frequency (RF) power coupler has developed two 700-MHz, helium gas-cooled power couplers. One has a fixed inner conductor and the other has an adjustable inner conductor (gamma prototype and alpha prototype). The power couplers will be performance tested in the near future. This paper discusses the mechanical design and fabrication techniques employed in the development of each power coupler. This includes material selection, copper coating, assembly sequences, and metal joining procedures, as well as the engineering analyses performed to determine the dynamic response of the inner conductors due to environmental excitations. A bellows is used in both prototype inner conductors in the area near the ceramic RF window, to compensate for thermal expansion and mechanical tolerance build-up. In addition, a bellows is used near the tip of the inner conductor of the alpha prototype for running the power coupler after it is installed on the accelerator. Extensive analytical work has been performed to determine the static loads transmitted by the bellows due to thermally induced expansion on the inner conductor and on the RF window. This paper also discusses this analysis, as well as the mechanical analysis performed to determine the final geometric shape of the bellows. Finally, a discussion of the electromagnetic analysis used to optimize the performance of the power couplers is included.

Induction of apoptosis in HeLa cancer cells by an ultrasonic-mediated synthesis of curcumin-loaded chitosan–alginate–STPP nanoparticles

Directory of Open Access Journals (Sweden)

Ahmadi F

2017-11-01

Full Text Available Fatemeh Ahmadi,1 Maryam Ghasemi-Kasman,2,3 Shahram Ghasemi,4 Maryam Gholamitabar Tabari,5 Roghayeh Pourbagher,2 Sohrab Kazemi,6 Ali Alinejad-Mir7 1Student Research Committee, Babol University of Medical Sciences, 2Cellular and Molecular Biology Research Center, 3Neuroscience Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran; 4Faculty of Chemistry, University of Mazandaran, Babolsar, Iran; 5Infertility and Health Reproductive Research Center, Health Research Institute, 6Cancer Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran; 7Department of Chemical Engineering, University of Mazandaran, Babolsar, Iran Abstract: Natural herbal compounds have been widely introduced as an alternative therapeutic approach in cancer therapy. Despite potent anticancer activity of curcumin, its clinical application has been limited because of low water solubility and resulting poor bioavailability. In this study, we designed a novel ultrasonic-assisted method for the synthesis of curcumin-loaded chitosan–alginate–sodium tripolyphosphate nanoparticles (CS-ALG-STPP NPs. Furthermore, antitumor effect of curcumin-loaded NPs was evaluated in vitro. Field emission scanning electron microscopy (FE-SEM and atomic force microscopy (AFM were used to characterize the properties of NPs. Antitumor activity of curcumin-loaded NPs was assessed by using MTT and quantitative real-time polymerase chain reaction (qRT-PCR. FE-SEM and AFM data revealed the spherical morphology, and the average size of NPs was <50 nm. In vitro cytotoxicity assay suggested that curcumin-loaded CS-ALG-STPP NPs displayed significant antitumor activity compared with the free curcumin. Gene expression level analyses showed that curcumin NPs significantly increased the apoptotic gene expression. Collectively, our results suggest that curcumin-loaded NPs significantly suppressed proliferation and promoted the induction of

Preparation of reduced graphene oxide/meso-TiO_2/AuNPs ternary composites and their visible-light-induced photocatalytic degradation n of methylene blue

International Nuclear Information System (INIS)

Yang, Yongfang; Ma, Zheng; Xu, Lidong; Wang, Hefang; Fu, Nian

2016-01-01

Graphical abstract: Reduced graphene oxide/meso-TiO_2/AuNPs (RGO/meso-TiO_2/AuNPs) ternary composites were prepared via the addition of graphene oxide to the dispersion of meso-TiO_2/AuNPs under a hydrothermal condition. The RGO/meso-TiO_2/AuNPs ternary composites show high photocatalytic activity toward MB. - Highlights: • RGO/meso-TiO_2/AuNPs were obtained by addition of graphene oxide to meso-TiO_2/AuNPs. • Au NPs in the mesopores of meso-TiO_2 reduce the recombination of charge carriers. • RGO covered with the surface of the meso-TiO_2 enhance the adsorption of MB. • RGO/meso-TiO_2/AuNPs composites show high photocatalytic performance toward MB. - Abstract: Reduced graphene oxide/meso-TiO_2/AuNPs (RGO/meso-TiO_2/AuNPs) ternary composites were prepared via the addition of graphene oxide to the dispersion of meso-TiO_2/AuNPs under hydrothermal conditions. The structure and the morphology of the RGO/meso-TiO_2/AuNPs materials were characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The photocatalytic activity of RGO/meso-TiO_2/AuNPs was evaluated by degradation of methyl blue (MB) under visible-light illumination. The ternary composites present an extended light absorption range, efficient charge separation properties, high adsorption ability for MB and high photocatalytic degradation activity of MB compared to the meso-TiO_2 and meso-TiO_2/AuNPs.

Plasmon-enhanced luminescence of Sm complex using silver nanoparticles in Polyvinyl Alcohol

Energy Technology Data Exchange (ETDEWEB)

Kaur, Gagandeep; Verma, R.K.; Rai, D.K. [Laser and Spectroscopy Laboratory, Department of Physics, Banaras Hindu University, India 221005 (India); Rai, S.B., E-mail: sbrai49@yahoo.co.in [Laser and Spectroscopy Laboratory, Department of Physics, Banaras Hindu University, India 221005 (India)

2012-07-15

Silver (Ag) nanoparticles (NPs) were prepared by laser ablation in water with an aim to enhance the luminescence of rare earth coordinated complex in polymer host. A fixed concentration of the complex containing Samarium (Sm), Salicylic acid (Sal) and 1, 10-phenanthroline (Phen) were combined with different concentrations of silver NPs in PolyVinyl Alcohol at room temperature. Absorption spectrum and XRD patterns of the sample show that the Sm(Sal){sub 3}Phen complex is accompanied by Ag NPs. The luminescence from the complex was recorded in the presence and absence of Ag NPs using two different excitation wavelengths viz. 400 and 355 nm. Of these, 400 nm radiation falls in the surface plasmon resonance of Ag NPs. It was found that the Ag NPs led to a significant enhancement in luminescence of the complex. Surprisingly, a high concentration of Ag NPs tends to quench the luminescence. - Highlights: Black-Right-Pointing-Pointer Sm complex with Ag nanoparticles in PVA was prepared at room temperature. Black-Right-Pointing-Pointer UV-vis absorption and XRD confirms the presence of Sm complex and Ag NPs. Black-Right-Pointing-Pointer Enhancement in luminescence of complex was observed with Ag NPs. Black-Right-Pointing-Pointer Coupling between radiative transitions of Sm and SPR of NPs enhances the emission. Black-Right-Pointing-Pointer The higher concentration of Ag NPs quenches the luminescence of the complex.

Dual stimuli-sensitive dendrimers: Photothermogenic gold nanoparticle-loaded thermo-responsive elastin-mimetic dendrimers.

Science.gov (United States)

Fukushima, Daichi; Sk, Ugir Hossain; Sakamoto, Yasuhiro; Nakase, Ikuhiko; Kojima, Chie

2015-08-01

Dendrimers are synthetic macromolecules with unique structures that can work as nanoplatforms for both photothermogenic gold nanoparticles (AuNPs) and thermosensitive elastin-like peptides (ELPs) with valine-proline-glycine-valine-glycine (VPGVG) repeats. In this study, photothermogenic AuNPs were loaded into thermo-responsive elastin-mimetic dendrimers (dendrimers conjugating ELPs at their periphery) to produce dual stimuli-sensitive nanoparticles. Polyamidoamine G4 dendrimers were modified with acetylated VPGVG and (VPGVG)2, and the resulting materials were named ELP1-den and ELP2-den, respectively. The AuNPs were prepared by the reduction of Au ions using a dendrimer-nanotemplated method. The AuNP-loaded elastin-mimetic dendrimers exhibited photothermal properties. ELP1-den and ELP2-den showed similar temperature-dependent changes in their conformations. Phase transitions were observed at around 55°C and 35°C for the AuNP-loaded ELP1-den and AuNP-loaded ELP2-den, respectively, but not for the corresponding PEGylated dendrimer. In contrast to the AuNP-loaded PEGylated dendrimer, AuNP-loaded ELP2-den readily associated with cells and induced efficient photocytotoxicity at 37°C. The cell association and the photocytotoxicity properties of AuNP-loaded ELP2-den could be controlled by temperature. These results therefore suggest that dual stimuli-sensitive dendrimer nanoparticles of this type could be used for photothermal therapy. Copyright © 2015 Elsevier B.V. All rights reserved.

Novel sulpiride-loaded solid lipid nanoparticles with enhanced intestinal permeability

Directory of Open Access Journals (Sweden)

Ibrahim WM

2013-12-01

Full Text Available Waheed M Ibrahim,1 Abdullah H AlOmrani,2 Alaa Eldeen B Yassin31Drug Sector, Saudi Food and Drug Authority, 2Department of Pharmaceutics, College of Pharmacy, King Saud University, 3Department of Pharmaceutical Sciences, College of Pharmacy, King Saud bin Abdulaziz University for Health Sciences, National Guard Health Affairs, Riyadh, Saudi ArabiaBackground: Solid lipid nanoparticles (SLN, novel drug delivery carriers, can be utilized in enhancing both intestinal permeability and dissolution of poorly absorbed drugs. The aim of this work was to enhance the intestinal permeability of sulpiride by loading into SLN.Methods: A unique ultrasonic melt-emulsification method with minimum stress conditions was used for the preparation of SLN. The mixture of the drug and the melted lipids was simply dispersed in an aqueous solution of a surfactant at a temperature that was 10°C higher than the melting points of the lipids using probe sonication, and was then simultaneously dispersed in cold water. Several formulation parameters were optimized, including the drug-to-lipid ratio, and the types of lipids and surfactants used. The produced SLN were evaluated for their particle size and shape, surface charge, entrapment efficiency, crystallinity of the drug and lipids, and the drug release profile. The rat everted sac intestine model was utilized to evaluate the change in intestinal permeability of sulpiride by loading into SLN.Results: The method adopted allowed successful preparation of SLN with a monodispersed particle size of 147.8–298.8 nm. Both scanning electron microscopic and atomic force microscopic images showed uniform spherical particles and confirmed the sizes determined by the light scattering technique. Combination of triglycerides with stearic acid resulted in a marked increase in zeta potential, entrapment efficiency, and drug loading; however, the particle size was increased. The type of surfactant used was critical for particle size

The Interactions between ZnO Nanoparticles (NPs and α-Linolenic Acid (LNA Complexed to BSA Did Not Influence the Toxicity of ZnO NPs on HepG2 Cells

Directory of Open Access Journals (Sweden)

Yiwei Zhou

2017-04-01

Full Text Available Background: Nanoparticles (NPs entering the biological environment could interact with biomolecules, but little is known about the interaction between unsaturated fatty acids (UFA and NPs. Methods: This study used α-linolenic acid (LNA complexed to bovine serum albumin (BSA for UFA and HepG2 cells for hepatocytes. The interactions between BSA or LNA and ZnO NPs were studied. Results: The presence of BSA or LNA affected the hydrodynamic size, zeta potential, UV-Vis, fluorescence, and synchronous fluorescence spectra of ZnO NPs, which indicated an interaction between BSA or LNA and NPs. Exposure to ZnO NPs with the presence of BSA significantly induced the damage to mitochondria and lysosomes in HepG2 cells, associated with an increase of intracellular Zn ions, but not intracellular superoxide. Paradoxically, the release of inflammatory cytokine interleukin-6 (IL-6 was decreased, which indicated the anti-inflammatory effects of ZnO NPs when BSA was present. The presence of LNA did not significantly affect all of these endpoints in HepG2 cells exposed to ZnO NPs and BSA. Conclusions: the results from the present study indicated that BSA-complexed LNA might modestly interact with ZnO NPs, but did not significantly affect ZnO NPs and BSA-induced biological effects in HepG2 cells.

Enhanced electroactive and mechanical properties of poly(vinylidene fluoride) by controlling crystallization and interfacial interactions with low loading polydopamine coated BaTiO₃.

Science.gov (United States)

Jia, Nan; Xing, Qian; Liu, Xu; Sun, Jing; Xia, Guangmei; Huang, Wei; Song, Rui

2015-09-01

Poly(vinylidene fluoride) (PVDF) is a semi-crystalline polymer and the polar β-phase of PVDF shows superb electroactive properties. In order to enhance the β-phase of PVDF, extreme low content of BaTiO3 nanoparticles (BT-NPs) coated with polydopamine (Pdop) were incorporated into PVDF matrix by solution casting. The β-phase of the resulting PVDF nanocomposites film was dramatically increased and the d33 value reached 34.3±0.4 pCN(-1). It is found that the Pdop layer could improve the dispersibility and stability of the BT NPs in solution and endow the BT NPs good dispersity in the PVDF matrix. Moreover, the interfacial interaction between PVDF chains and the surface of BT-Pdop nanoparticles (BT-Pdop NPs) were revealed, in which the CF2 groups on PVDF could interact with the electron-rich plane of aromatic ring of Pdop moiety. This interaction, led to the increase of the crystallization activation energy as derived from the DSC nonisothermal crystallization measurement. The α-β crystal transformation, organization of interfacial interactions as well as the prevention of agglomeration of BT-NPs confer the improvement of mechanical and thermal properties of PVDF, such as toughness, tensile strength, elongation at break, and thermal conductivity. Copyright © 2015 Elsevier Inc. All rights reserved.

Andrographolide-loaded nanoparticles for brain delivery: Formulation, characterisation and in vitro permeability using hCMEC/D3 cell line.

Science.gov (United States)

Guccione, Clizia; Oufir, Mouhssin; Piazzini, Vieri; Eigenmann, Daniela Elisabeth; Jähne, Evelyn Andrea; Zabela, Volha; Faleschini, Maria Teresa; Bergonzi, Maria Camilla; Smiesko, Martin; Hamburger, Matthias; Bilia, Anna Rita

2017-10-01

Andrographolide (AG) is a major diterpenoid of the Asian medicinal plant Andrographis paniculata which has shown exciting pharmacological potential for the treatment of inflammation-related pathologies including neurodegenerative disorders. Conversely, the low bioavailability of AG still represents a limiting factor for its use. To overcome these limitations, AG was loaded into human serum albumin based nanoparticles (HSA NPs) and poly ethylcyanoacrylate nanoparticles (PECA NPs). HSA NPs were prepared by thermal (HSAT AG NPs) and chemical cross-linking (HSAC AG NPs), while PECA AG NPs were produced by emulsion-polymerization. NPs were characterized in terms of size, zeta (ζ)-potential, polydispersity, and release studies of AG. In addition, the ability of free AG and AG-loaded in PECA and HSAT NPs to cross the blood-brain barrier (BBB) was assessed using an in vitro BBB model based on human cerebral microvascular endothelial cell line (hCMEC/D3). For BBB drug permeability assays, a quantitative UPLC-MS/MS method for AG in Ringer HEPES buffer was developed and validated according to international regulatory guidelines for industry. Free AG did not permeate the BBB model, as also predicted by in silico studies. HSAT NPs improved by two-fold the permeation of AG while maintaining the integrity of the cell layer, while PECA NPs temporarily disrupted BBB integrity. Copyright © 2017 Elsevier B.V. All rights reserved.

Aptamer-functionalized nano-biosensors.

Science.gov (United States)

Chiu, Tai-Chia; Huang, Chih-Ching

2009-01-01

Nanomaterials have become one of the most interesting sensing materials because of their unique size- and shape-dependent optical properties, high surface energy and surface-to-volume ratio, and tunable surface properties. Aptamers are oligonucleotides that can bind their target ligands with high affinity. The use of nanomaterials that are bioconjugated with aptamers for selective and sensitive detection of analytes such as small molecules, metal ions, proteins, and cells has been demonstrated. This review focuses on recent progress in the development of biosensors by integrating functional aptamers with different types of nanomaterials, including quantum dots, magnetic nanoparticles (NPs), metallic NPs, and carbon nanotubes. Colorimetry, fluorescence, electrochemistry, surface plasmon resonance, surface-enhanced Raman scattering, and magnetic resonance imaging are common detection modes for a broad range of analytes with high sensitivity and selectivity when using aptamer bioconjugated nanomaterials (Apt-NMs). We highlight the important roles that the size and concentration of nanomaterials, the secondary structure and density of aptamers, and the multivalent interactions play in determining the specificity and sensitivity of the nanosensors towards analytes. Advantages and disadvantages of the Apt-NMs for bioapplications are focused.

Aptamer-Functionalized Nano-Biosensors

Directory of Open Access Journals (Sweden)

Tai-Chia Chiu

2009-12-01

Full Text Available Nanomaterials have become one of the most interesting sensing materials because of their unique size- and shape-dependent optical properties, high surface energy and surface-to-volume ratio, and tunable surface properties. Aptamers are oligonucleotides that can bind their target ligands with high affinity. The use of nanomaterials that are bioconjugated with aptamers for selective and sensitive detection of analytes such as small molecules, metal ions, proteins, and cells has been demonstrated. This review focuses on recent progress in the development of biosensors by integrating functional aptamers with different types of nanomaterials, including quantum dots, magnetic nanoparticles (NPs, metallic NPs, and carbon nanotubes. Colorimetry, fluorescence, electrochemistry, surface plasmon resonance, surface-enhanced Raman scattering, and magnetic resonance imaging are common detection modes for a broad range of analytes with high sensitivity and selectivity when using aptamer bioconjugated nanomaterials (Apt-NMs. We highlight the important roles that the size and concentration of nanomaterials, the secondary structure and density of aptamers, and the multivalent interactions play in determining the specificity and sensitivity of the nanosensors towards analytes. Advantages and disadvantages of the Apt-NMs for bioapplications are focused.

APTES Functionalized Iron Oxide-Silver Magnetic Hetero-Nanocomposites for Selective Capture and Rapid Removal of Salmonella enteritidis from Aqueous Solution

Science.gov (United States)

Trang, Vu Thi; Dinh, Ngo Xuan; Lan, Hoang; Tam, Le Thi; Huy, Tran Quang; Tuan, Pham Anh; Phan, Vu Ngoc; Le, Anh-Tuan

2018-02-01

Magnetic nanomaterials, as a promising platform for the fast and sensitive detection of bacterial pathogens, have attracted increasing interest from researchers in recent years. In this work, by utilizing a two-step synthetic technique consisting of co-precipitation and subsequent hydrothermal reaction, followed by functionalization steps with (3-aminopropyl)triethoxysilane (APTES) and the antibody against Salmonella enteritidis, antibody-conjugated Fe3O4-Ag@APTES hetero-nanocomposites were successfully prepared. Due to the specific antibody, the developed Fe3O4-Ag@APTES@SE-Ab conjugates are capable of selectively capturing S. enteritidis at a low concentration of about 101 CFU/mL. Moreover, the prepared magnetic conjugates also revealed that the S. enteritidis could be rapidly removed from water solution in 20 min by using an external magnetic field with a removal efficiency obtained of ˜ 91.36%. These results indicated that the Fe3O4-Ag@APTES@SE-Ab conjugates are promising for the rapid selective capture and removal of bacterial pathogens from aqueous environments, and can be used for improving the detection quality of pathogens in water samples using immunosensor-based diagnostic tests.

Development of a RAMI model for LANSCE and high power APT accelerators

International Nuclear Information System (INIS)

Tallerico, P.J.

1994-01-01

Assessment of the reliability, availability, maintainability and inspectability (RAMI) of all high power, high cost systems is important to justify and improve the cost effectiveness of these systems. For the very large (over 100 MW) accelerator systems associated with APT, a RAMI model is very valuable in guiding the design and allocation of resources. A RAMI model of an existing machine is also valuable, since machine improvement funds must be allocated to increase the availability by the largest amount. The authors have developed a RAMI model using the critical subsystems of the LANSCE accelerator and beam delivery complex as an example and to evaluate the effectiveness for estimating reliability and beam availability. LAMPF and LANSCE together provide most of the features required for the accelerator and beam delivery part of a high-power APT machine, but LANSCE is pulsed, rather than CW. This complex is capable of a 1-MW average power H - beam, and it is the most powerful proton accelerator in the US built to date

Development of docetaxel and alendronate-loaded chitosan ...

African Journals Online (AJOL)

Development of docetaxel and alendronate-loaded chitosan-conjugated polylactide-co-glycolide nanoparticles: In vitro characterization in osteosarcoma cells. ... typical time-dependent cellular uptake and also displayed superior cytotoxicity in MG-63 cells compared with blank NPs, which were safe and biocompatible.

Quantum-chemical prediction of the effects of Ni-loading on the hydrogenation and water-splitting efficiency of TiO2 nanoparticles with an experimental test

Science.gov (United States)

Lin, Cheng-Kuo; Chuang, Chung-Ching; Raghunath, Putikam; Srinivasadesikan, V.; Wang, T. T.; Lin, M. C.

2017-01-01

The effects of Ni-loading on TiO2 nanoparticles can pronouncedly reduce the barriers for dissociation of H2 from 48 kcal/mol on the pure TiO2 to as low as 1-3 kcal/mol on the loaded samples facilitating the hydrogenation of NPs. Preliminary data of our test indicate that the hydrogenation of Ni-loaded TiO2 NPs results in a significant UV-visible absorption extending well beyond 750 nm with an increase in water splitting efficiency by as much as 67 times over those of pure and hydrogenated TiO2 NPs without Ni-loading under our mild hydrogenation condition using 800 Torr of H2 at 300 °C for 3 h.

Synthesis and characterization of lanthanide-based luminescent nanoparticles: toward new bio-labels

International Nuclear Information System (INIS)

Lechevallier, Severine

2010-01-01

This work deals with the development of luminescent nanoparticles (NPs) suitable as bio-labels. Inorganic NPs have been synthesized, in which luminescent ion (Eu 3+ in most of cases) is substituting ions of the oxide host matrix. NPs of Ln(OH)CO 3 :Eu 3+ (Ln = Y or Gd), Ln 2 O 3 :Eu 3+ , Ln 2 O 2 S:Eu 3+ and SiO 2 :Eu 3+ have been characterized by the way of TGA, WAXS-XRD, TEM, IR and photoluminescence (PL) techniques. The controlled precipitation using urea as precipitating agent is the way chosen and optimized to obtain spherical and monodispersed in size (150±15 nm) NPs. These particles of amorphous lanthanide hydroxycarbonate can directly be used as luminescent bio-labels or after their conversion in oxide or oxi-sulfide. For the silica particles, the synthesis by aerosol pyrolysis has been used. The obtained particles are spherical with a main diameter of 350 nm. In a second step, the surface of the inorganic NPs has been modified, in order to graft amino-reactive functions. Several modification ways have been explored: with APTES (aminopropyltriethoxysilane), with TEOS (tetra-ethoxysilane) and then APTES, or with a TEOS/APTES mixture. The same characterizations techniques have been applied to the modified particles, and chemical analysis, solid state NMR and XPS. DLS and ζ-potential of the NPs dispersed in water have also been measured. These analyses have been completed by the evaluation of the number of accessible amine functions by coupling with FITC (fluorescein isothiocyanate). The direct modification of oxides (Y 2 O 3 or Gd 2 O 3 ) with APTES is the best way, and an homogenous layer of 1 nm with a high number of accessible amine can be graft. Finally, to move toward luminescent bio-labelling in biological medium, the luminescence of the NPs has been observed and analyzed using: - A spectro-fluorimeter, after their dispersion in water; - A fluorescence microscope, on glass slides, under broad band excitation; - A confocal microscope, under laser

Magnetic Enrichment of Dendritic Cell Vaccine in Lymph Node with Fluorescent-Magnetic Nanoparticles Enhanced Cancer Immunotherapy

Science.gov (United States)

Jin, Honglin; Qian, Yuan; Dai, Yanfeng; Qiao, Sha; Huang, Chuan; Lu, Lisen; Luo, Qingming; Chen, Jing; Zhang, Zhihong

2016-01-01

Dendritic cell (DC) migration to the lymph node is a key component of DC-based immunotherapy. However, the DC homing rate to the lymphoid tissues is poor, thus hindering the DC-mediated activation of antigen-specific T cells. Here, we developed a system using fluorescent magnetic nanoparticles (α-AP-fmNPs; loaded with antigen peptide, iron oxide nanoparticles, and indocyanine green) in combination with magnetic pull force (MPF) to successfully manipulate DC migration in vitro and in vivo. α-AP-fmNPs endowed DCs with MPF-responsiveness, antigen presentation, and simultaneous optical and magnetic resonance imaging detectability. We showed for the first time that α-AP-fmNP-loaded DCs were sensitive to MPF, and their migration efficiency could be dramatically improved both in vitro and in vivo through MPF treatment. Due to the enhanced migration of DCs, MPF treatment significantly augmented antitumor efficacy of the nanoparticle-loaded DCs. Therefore, we have developed a biocompatible approach with which to improve the homing efficiency of DCs and subsequent anti-tumor efficacy, and track their migration by multi-modality imaging, with great potential applications for DC-based cancer immunotherapy. PMID:27698936

Cyclodextrin-PEG conjugate-wrapped magnetic ferrite nanoparticles for enhanced drug loading and release

Science.gov (United States)

Enoch, Israel V. M. V.; Ramasamy, Sivaraj; Mohiyuddin, Shanid; Gopinath, Packirisamy; Manoharan, R.

2018-05-01

Magnetic nanoparticles are envisaged to overcome the impediments in the methods of targeted drug delivery and hence cure cancer effectively. We report herein, manganese ferrite nanoparticles, coated with β-cyclodextrin-modified polyethylene glycol as a carrier for the drug, camptothecin. The particles are of the size of 100 nm and they show superparamagnetic behaviour. The saturation magnetization does not get diminished on polymer coverage of the nanoparticles. The β-cyclodextrin-polyethylene glycol conjugates are characterized using NMR and mass spectrometric techniques. By coating the magnetic nanoparticles with the cyclodextrin-tethered polymer, the drug-loading capacity is enhanced and the observed release of the drug is slow and sustained. The cell viability of HEK293 and HCT15 cells is evaluated and the cytotoxicity is enhanced when the drug is loaded in the polymer-coated magnetic nanoparticles. The noncovalent-binding based and enhanced drug loading on the nanoparticles and the sustained release make the nanocarrier a promising agent for carrying the payload to the target.

Study of energy transfer between riboflavin (vitamin B2) and AgNPs

Science.gov (United States)

Mokashi, Vidya V.; Walekar, Laxman S.; Anbhule, Prashant V.; Lee, Sang Hak; Patil, Shivajirao R.; Kolekar, Govind B.

2014-03-01

Here, we report the studies on the interaction and formation of nanobiocomplex between silver nanoparticle (AgNPs) and vitamin B2, i.e., riboflavin (RF). The binding study of AgNP to RF was studied by fluorescence, UV-Vis, and TEM techniques. AgNPs were prepared by reducing AgNO3 with trisodium citrate. Prepared nanoparticles size obtained at 20 nm having surface Plasmon resonance band at 426 nm. The absorbance band of RF at 264, 374, and 444 nm changes significantly in the presence of AgNPs suggests that there is change in the chemical environment surrounding AgNPs. A fluorescence spectral change for a solution of RF upon the addition of AgNPs and rapid quenching is suggestive of a rapid adsorption of RF on AgNPs.

A novel nanoparticles impregnated ocular insert for enhanced bioavailability to posterior segment of eye: In vitro, in vivo and stability studies

Energy Technology Data Exchange (ETDEWEB)

Rathod, Lalaji V.; Kapadia, Rakhee; Sawant, Krutika K., E-mail: dr_krutikasawant@rediffmail.com

2017-02-01

The present investigation was carried out to demonstrate with the help of in vitro and in vivo studies that nanoparticles impregnated ocular inserts effectively delivers significant concentration of drug to the posterior segment of eye after topical administration for treatment of glaucoma. Drug loaded Nanoparticles and their ocular insert have been reported to reduce side effects of orally administered Acetazolamide. Eudragit NPs were prepared by the solvent diffusion nanoprecipitation technique. The prepared NPs were evaluated for various parameters such as particle size, zeta potential, % entrapment efficiency, % drug loading, DSC, FTIR, TEM and stability studies. Ocular inserts of NPs were prepared by solvent casting method. The prepared ocular inserts were evaluated for thickness, content uniformity, folding endurance, disintegration time, morphology and stability study. The NPs and ocular inserts were evaluated for in-vitro drug diffusion study, ex-vivo trans-corneal permeability study, in-vivo ocular tolerability and intra ocular pressure (IOP) reduction study. The optimized batch was stable for a period of 3 months in lyophilized form. The optimized formulations had size range of 367 nm ± 8 nm, zeta potential around + 7 mV ± 1.3 mV and 51.61% ± 3.84% entrapment efficiency with 19% ± 1.40% drug loading. The ex-vivo trans-corneal study showed higher cumulative corneal permeation, flux across corneal tissue (2.460 ± 0.028 μg/ml) and apparent corneal permeability (3.926 × 10{sup −6} cm{sup 2}/s & 3.863 × 10{sup −6} cm{sup 2}/s) from drug loaded Eudragit NPs and Ocular inserts as compared to drug solution (0.671 ± 0.020 μg/ml & 3.166 × 10{sup −6} cm{sup 2}/s). In-vivo study showed the Eudragit NPs and ocular insert produced significant (P < 0.001) lowering in intra ocular pressure compared with the solution of free drug after 3 h of topical ocular administration. Plain Eudragit NPs caused no inflammation and/or discomfort in rabbit eyes and

A novel nanoparticles impregnated ocular insert for enhanced bioavailability to posterior segment of eye: In vitro, in vivo and stability studies

International Nuclear Information System (INIS)

Rathod, Lalaji V.; Kapadia, Rakhee; Sawant, Krutika K.

2017-01-01

The present investigation was carried out to demonstrate with the help of in vitro and in vivo studies that nanoparticles impregnated ocular inserts effectively delivers significant concentration of drug to the posterior segment of eye after topical administration for treatment of glaucoma. Drug loaded Nanoparticles and their ocular insert have been reported to reduce side effects of orally administered Acetazolamide. Eudragit NPs were prepared by the solvent diffusion nanoprecipitation technique. The prepared NPs were evaluated for various parameters such as particle size, zeta potential, % entrapment efficiency, % drug loading, DSC, FTIR, TEM and stability studies. Ocular inserts of NPs were prepared by solvent casting method. The prepared ocular inserts were evaluated for thickness, content uniformity, folding endurance, disintegration time, morphology and stability study. The NPs and ocular inserts were evaluated for in-vitro drug diffusion study, ex-vivo trans-corneal permeability study, in-vivo ocular tolerability and intra ocular pressure (IOP) reduction study. The optimized batch was stable for a period of 3 months in lyophilized form. The optimized formulations had size range of 367 nm ± 8 nm, zeta potential around + 7 mV ± 1.3 mV and 51.61% ± 3.84% entrapment efficiency with 19% ± 1.40% drug loading. The ex-vivo trans-corneal study showed higher cumulative corneal permeation, flux across corneal tissue (2.460 ± 0.028 μg/ml) and apparent corneal permeability (3.926 × 10 −6 cm 2 /s & 3.863 × 10 −6 cm 2 /s) from drug loaded Eudragit NPs and Ocular inserts as compared to drug solution (0.671 ± 0.020 μg/ml & 3.166 × 10 −6 cm 2 /s). In-vivo study showed the Eudragit NPs and ocular insert produced significant (P < 0.001) lowering in intra ocular pressure compared with the solution of free drug after 3 h of topical ocular administration. Plain Eudragit NPs caused no inflammation and/or discomfort in rabbit eyes and neither affected the intra

NPS Solar Cell Array Tester Cubesat Flight Testing and Integration

Science.gov (United States)

2014-09-01

with current (I). P V I      (2.1) This is significant because the battery discharge test will not lineup perfectly with Figure 12...accordance with the charging procedures [13]. 3. NPS-SCAT Power Budget A power budget analysis was performed to determine if the NPS-SCAT is self...using procedures developed by Marissa Brummitt, and with the assistance of Adam Hill, NPS-SCAT Program Manager. 1. ELaNa IV Random Vibration Levels

Barbaloin loaded polydopamine-polylactide-TPGS (PLA-TPGS) nanoparticles against gastric cancer as a targeted drug delivery system: Studies in vitro and in vivo.

Science.gov (United States)

Wang, Yi-Ran; Yang, Shi-Yan; Chen, Guang-Xia; Wei, Ping

2018-04-30

Gastric cancer is the third leading cause of cancer-associated death worldwide. Although a decrease in its incidence is observed, gastric cancer still poses a major clinical challenge due to poor prognosis and limited treatments. Barbaloin (BBL) is a main medicinal composition of the Chinese traditional medicine aloe vera. BBL has various bioactivities, including anti-oxidant, anti-inflammatory and anti-tumor properties. Polydopamine (pD)-based surface modification is easy to functionalize polymeric nanoparticles (NPs) surfaces with ligands and/or additional polymeric layers. In the present study, BBL-loaded formulations was developed with pD-modified NPs, which was synthesized by polylactide-TPGS (PLA-TPGS) (pD-PLA-TPGS/NPs). And galactosamine (Gal) was conjugated on the prepared NPs (Gal-pD-PLA-TPGS/NPs) for targeting the gastric cancer cells. Here, we found that BBL-loaded Gal-pD-PLA-TPGS/NPs showed the highest cellular uptake efficacy in gastric cancer cells. Gal-pD-PLA-TPGS/NPs more significantly reduced the gastric cancer cell viability. Further, greater apoptosis, autophagy and ROS generation was induced by Gal-pD-PLA-TPGS/NPs in gastric cancer cells. Additionally, compared to the other two NPs, Gal-pD-PLA-TPGS/NPs most markedly decreased ATP levels in gastric cancer cells. In vivo, Gal-pD-PLA-TPGS/NPs were specifically targeted to tumor site. Moreover, Gal-pD-PLA-TPGS/NPs exhibited the most anti-tumor effects, as evidenced by the lowest tumor volume and tumor weight. Of note, there was no significant difference was observed in body and liver weight, as well as the histological changes in major organs isolated from each group of mice. Together, the findings indicated that BBL-loaded Gal-pD-PLA-TPGS/NPs could be targeted to gastric cancer cells to suppress tumor progression without toxicity. Copyright © 2018. Published by Elsevier Inc.

Preparation of reduced graphene oxide/meso-TiO{sub 2}/AuNPs ternary composites and their visible-light-induced photocatalytic degradation n of methylene blue

Energy Technology Data Exchange (ETDEWEB)

Yang, Yongfang; Ma, Zheng; Xu, Lidong [School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin 300130 (China); Wang, Hefang, E-mail: whf0618@163.com [School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin 300130 (China); Fu, Nian, E-mail: funian3678@163.com [School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin 300130 (China); College of Physics Science and Technology of Hebei University, Baoding 071002 (China)

2016-04-30

Graphical abstract: Reduced graphene oxide/meso-TiO{sub 2}/AuNPs (RGO/meso-TiO{sub 2}/AuNPs) ternary composites were prepared via the addition of graphene oxide to the dispersion of meso-TiO{sub 2}/AuNPs under a hydrothermal condition. The RGO/meso-TiO{sub 2}/AuNPs ternary composites show high photocatalytic activity toward MB. - Highlights: • RGO/meso-TiO{sub 2}/AuNPs were obtained by addition of graphene oxide to meso-TiO{sub 2}/AuNPs. • Au NPs in the mesopores of meso-TiO{sub 2} reduce the recombination of charge carriers. • RGO covered with the surface of the meso-TiO{sub 2} enhance the adsorption of MB. • RGO/meso-TiO{sub 2}/AuNPs composites show high photocatalytic performance toward MB. - Abstract: Reduced graphene oxide/meso-TiO{sub 2}/AuNPs (RGO/meso-TiO{sub 2}/AuNPs) ternary composites were prepared via the addition of graphene oxide to the dispersion of meso-TiO{sub 2}/AuNPs under hydrothermal conditions. The structure and the morphology of the RGO/meso-TiO{sub 2}/AuNPs materials were characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The photocatalytic activity of RGO/meso-TiO{sub 2}/AuNPs was evaluated by degradation of methyl blue (MB) under visible-light illumination. The ternary composites present an extended light absorption range, efficient charge separation properties, high adsorption ability for MB and high photocatalytic degradation activity of MB compared to the meso-TiO{sub 2} and meso-TiO{sub 2}/AuNPs.

Encapsulation method for atom probe tomography analysis of nanoparticles

International Nuclear Information System (INIS)

Larson, D.J.; Giddings, A.D.; Wu, Y.; Verheijen, M.A.; Prosa, T.J.; Roozeboom, F.; Rice, K.P.; Kessels, W.M.M.; Geiser, B.P.; Kelly, T.F.

2015-01-01

Open-space nanomaterials are a widespread class of technologically important materials that are generally incompatible with analysis by atom probe tomography (APT) due to issues with specimen preparation, field evaporation and data reconstruction. The feasibility of encapsulating such non-compact matter in a matrix to enable APT measurements is investigated using nanoparticles as an example. Simulations of field evaporation of a void, and the resulting artifacts in ion trajectory, underpin the requirement that no voids remain after encapsulation. The approach is demonstrated by encapsulating Pt nanoparticles in an ZnO:Al matrix created by atomic layer deposition, a growth technique which offers very high surface coverage and conformality. APT measurements of the Pt nanoparticles are correlated with transmission electron microscopy images and numerical simulations in order to evaluate the accuracy of the APT reconstruction. - Highlights: • Pt nanoparticles were analyzed using atom probe tomography and TEM. • The particles were prepared by encapsulation using atomic layer deposition. • Simulation of field evaporation near a void results in aberrations in ion trajectories. • Apparent differences between TEM and APT analyses are reconciled through simulation of field evaporation from a low-field matrix containing high-field NPs; ion trajectory aberrations are shown to lead to an apparent mixing of the matrix into the NPs.

Red light emitting nano-PVP fibers that hybrid with Ag@SiO2@Eu(tta)3phen-NPs by electrostatic spinning method

Science.gov (United States)

Zhang, Xiaolin; Tang, Jianguo; Li, Haidong; Wang, Yao; Wang, Xinzhi; Wang, Yanxin; Huang, Linjun; Belfiore, Laurence A.

2018-04-01

This work demonstrated red light emitting nano-PVP fibers that incorporated with novel three-layer nanostructure of Ag@SiO2@Eu(tta)3phen nanoparticles (Ag@SiO2@Eu(tta)3phen-NPs), and the hybrid nano-PVP fibers were fabricated via a remarkably simple electrostatic spinning method. For Ag@SiO2@Eu(tta)3phen-NPs, the thickness of SiO2 is optimized to obtain the maximum luminescent intensity, as results, the optimized thickness of SiO2 is 20 nm. And the corresponding luminescent intensity (612 nm) of the Ag@SiO2@Eu(tta)3phen-NPs is enhanced up to 10 times compared with the pure Eu(tta)3phen complex, which indicates that with 20 nm SiO2 thickness, the localized surface plasmon resonance (LSPR) effect of Ag@SiO2 exhibits highest performance for enhancing luminescence. Moreover, the luminescent PVP fibers emit bright red light under the fluorescence microscope, which definitely confirms that the microenvironment provided by PVP polymer is absolutely suitable for the fluorescent composites.

Doxorubicin-loaded poly (lactic-co-glycolic acid) nanoparticles coated with chitosan/alginate by layer by layer technology for antitumor applications.

Science.gov (United States)

Chai, Fujuan; Sun, Linlin; He, Xinyi; Li, Jieli; Liu, Yuanfen; Xiong, Fei; Ge, Liang; Webster, Thomas J; Zheng, Chunli

2017-01-01

Natural polyelectrolyte multilayers of chitosan (CHI) and alginate (ALG) were alternately deposited on doxorubicin (DOX)-loaded poly (lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) with layer by layer self-assembly to control drug release for antitumor activity. Numerous factors which influenced the multilayer growth on nano-colloidal particles were studied: polyelectrolyte concentration, NaCl concentration and temperature. Then the growth regime of the CHI/ALG multilayers was elucidated. The coated NPs were characterized by transmission electron microscopy, atomic force microscopy, X-ray diffraction and a zeta potential analyzer. In vitro studies demonstrated an undesirable initial burst release of DOX-loaded PLGA NPs (DOX-PLGA NPs), which was relieved from 55.12% to 5.78% through the use of the layer by layer technique. The release of DOX increased more than 40% as the pH of media decreased from 7.4 to 5.0. More importantly, DOX-PLGA (CHI/ALG) 3 NPs had superior in vivo tumor inhibition rates at 83.17% and decreased toxicity, compared with DOX-PLGA NPs and DOX in solution. Thus, the presently formulated PLGA-polyelectrolyte NPs have strong potential applications for numerous controlled anticancer drug release applications.

Highly effective photothermal chemotherapy with pH-responsive polymer-coated drug-loaded melanin-like nanoparticles

Directory of Open Access Journals (Sweden)

Zhang C

2017-03-01

Full Text Available Chengwei Zhang,1 Xiaozhi Zhao,1 Suhan Guo,2 Tingsheng Lin,1 Hongqian Guo1 1Department of Urology, Nanjing Drum Tower Hospital, Medical School of Nanjing University, Institute of Urology, Nanjing University, 2School of Public Health, Nanjing Medical University, Nanjing, People’s Republic of China Abstract: Dopamine is a neurotransmitter commonly used in clinical treatment. Polydopamine (PDA has excellent histocompatibility and biosafety and can efficiently convert near-infrared reflection (NIR to thermal energy. In this study, PDA was used as a promising carrier, and pH-responsive polymer-coated drug-loaded PDA nanoparticles (NPs; doxorubicin@poly(allylamine-citraconic anhydride [Dox@PAH-cit]/PDA NPs were developed. As expected, the Dox@PAH-cit/PDA NPs exhibited excellent photothermal efficiency. In addition, at a low pH condition, the loaded Dox was released from the NPs due to the amide hydrolysis of PAH-cit. Upon NIR exposure (808 nm, the temperature of the NP solution rapidly increases to kill tumor cells. Compared with unbound chemotherapy drugs, the NPs have a stronger cell uptake ability. In vivo, the PDA NPs were able to efficiently accumulate at the tumor location. After intravenous administration and NIR exposure, tumor growth was significantly inhibited. In summary, the present investigation demonstrated that the Dox@PAH-cit/PDA NPs presented highly effective photothermal chemotherapy for prostate cancer. Keywords: prostate cancer, photothermal therapy, near-infrared reflection, dopamine, PAH-cit, drug delivery 

Enhancement of Orthodontic Anchor Screw Stability Under Immediate Loading by Ultraviolet Photofunctionalization Technology.

Science.gov (United States)

Takahashi, Maiko; Motoyoshi, Mitsuru; Inaba, Mizuki; Hagiwara, Yoshiyuki; Shimizu, Noriyoshi

Ultraviolet (UV)-mediated photofunctionalization technology is intended to enhance the osseointegration capability of titanium implants. There are concerns about orthodontic anchor screws loosening under immediate loading protocols in adolescent orthodontic treatment. The purpose of this in vivo study was to evaluate the effects of photofunctionalization on the intrabony stability of orthodontic titanium anchor screws and bone-anchor screw contact under immediate loading in growing rats. Custom-made titanium anchor screws (1.4 mm in diameter and 4.0 mm in length) with or without photofunctionalization pretreatment were placed on the proximal epiphysis of the tibial bone in 6-week-old male Sprague-Dawley rats and were loaded immediately after placement. After 2 weeks of loading, the stability of the anchor screws was evaluated using a Periotest device, and the bone-anchor screw contact ratio (BSC) was assessed by a histomorphometric analysis using field-emission scanning electron microscopy. In the unloaded group, Periotest values (PTVs) were ~25 for UV-untreated screws and 13 for UVtreated screws (P < .01), while in the immediate-loading group, PTVs were 28 for UV-untreated screws and 16 for UV-treated screws (P < .05). Significantly less screw mobility was observed in both UV-treated groups regardless of the loading protocol. The BSC was increased ~1.8 fold for UV-treated screws, compared with UV-untreated screws, regardless of the loading protocol. Photofunctionalization enhanced the intrabony stability of orthodontic anchor screws under immediate loading in growing rats by increasing bone-anchor screw contact.

Nanoparticle-neural stem cells for targeted ovarian cancer treatment: optimization of silica nanoparticles for efficient drug loading

Science.gov (United States)

Patel, Z.; Berlin, J.; Abidi, W.

2018-02-01

One of the drugs used to treat ovarian cancer is cisplatin. However, cisplatin kills normal surrounding tissue in addition to cancer cells. To improve tumor targeting efficiency, our lab uses neural stem cells (NSCs), which migrate directly to ovarian tumors. If free cisplatin is loaded into NSCs for targeted drug delivery, it will kill the NSCs. To prevent the drug cisplatin from killing both the NSCs and normal surrounding tissue, our lab synthesizes silica nanoparticles (SiNPs) that act as a protective carrier. The big picture here is to maximize efficiency of tumor targeting using NSCs and minimize toxicity to these NSCs using SiNPs. The goal of this project is to optimize the stability of SiNPs, which is important for efficient drug loading. To do this, the concentration of tetraethyl orthosilicate (TEOS), one of the main components of SiNPs, was varied. We hypothesized that more TEOS equates to more stable SiNPs because TEOS contributes carbon to SiNPs, and thus a tightly-packed chemical structure results in a stable particle. Then, the stability of the SiNPs were checked in cell media and phosphate buffered saline (PBS). Lastly, the SiNPs were analyzed for their porosity using the transmission electron microscope (TEM). TEM imaging showed white spots in the 200-800 μL TEOS batches and no white spots in the 1000-1800 μL TEOS batches. The white spots were pores, which indicate instability. We concluded that the ultimate factor that determines the stability of SiNPs (100 nm) is the concentration of organic substance.

Preparation and antioxidant properties of selenium nanoparticles-loaded chitosan microspheres

Directory of Open Access Journals (Sweden)

Bai K

2017-06-01

Full Text Available Kaikai Bai,1,2 Bihong Hong,1,2 Jianlin He,1,2 Zhuan Hong,1,2 Ran Tan1,2 1Third Institute of Oceanography, 2Engineering Research Center of Marine Biological Resource, Comprehensive Utilization, State Oceanic Administration, Xiamen, People’s Republic of China Abstract: Selenium nanoparticles (SeNPs, as a special form of selenium (Se supplement, have attracted worldwide attention due to their favorable properties and unique bioactivities. Herein, an eco-friendly and economic way to prepare stable SeNPs is introduced. SeNPs were synthesized in aqueous chitosan (CTS and then embedded into CTS microspheres by spray-drying, forming selenium nanoparticles-loaded chitosan microspheres (SeNPs-M. The physicochemical properties including morphology, elemental state, size distribution and surface potential were investigated. Institute of Cancer Research mice were used as model animal to evaluate the bioactivities of SeNPs-M. Trigonal-phase SeNPs of ~35 nm were synthesized, and SeNPs-M physically embedding those SeNPs were successfully prepared. Amazingly, acute toxicity test indicated that SeNPs-M were much safer than selenite in terms of Se dose, with a LD50 of around 18-fold of that of selenite. In addition, SeNPs-M possessed powerful antioxidant activities, as evidenced by a dramatic increase of both Se retention and the levels of glutathione peroxidase, superoxide dismutase and catalase. The design of SeNPs-M can offer a new way for further development of SeNPs with a higher efficacy and better biosafety. Thus, SeNPs-M may be a potential candidate for further evaluation as an Se supplement with antioxidant properties and be used against Se deficiency in animals and human beings. Keywords: selenium, nano, microsphere, chitosan, antioxidant

Preparation and characterization of BC/PAM-AgNPs nanocomposites for antibacterial applications.

Science.gov (United States)

Yang, Guang; Wang, Caixia; Hong, Feng; Yang, Xuexia; Cao, Zhangjun

2015-01-22

In this work, a bacterial cellulose/polyacrylamide (BC/PAM) double network composite was prepared to act as the template for in situ synthesis of silver nanoparticles (AgNPs). Effects of reaction conditions of the BC/PAM composite were investigated on its microstructure, mechanical properties and thermal stabilities. Both the BC/PAM composite and pure BC were utilized to prepare the corresponding silver impregnated nanocomposites, i.e., BC/PAM-AgNPs and BC-AgNPs, by an environmental friendly method, UV irradiation. The influences of the templates were investigated on the AgNPs formation and the antibacterial activities of the nanocomposites by both the zone of inhibition and dynamic shake flask methods. It was shown that the BC/PAM composite displayed a denser microstructure and higher thermal stabilities than pure BC. The BC/PAM-AgNPs nanocomposite exhibited a bigger particle size and lower mass content of AgNPs than the BC-AgNPs one. For the antibacterial test, two nanocomposites exhibited a close antibacterial effect, with a high log reduction above 3 and killing ratio above 99.9%, respectively. Copyright © 2014 Elsevier Ltd. All rights reserved.

Prevalence of antibodies to prothrombin in solid phase (aPT) and to phosphatidylserine-prothrombin complex (aPS/PT) in patients with and without lupus anticoagulant.

Science.gov (United States)

Bertolaccini, Maria Laura; Sciascia, Savino; Murru, Veronica; Garcia-Fernandez, Cesar; Sanna, Giovanni; Khamashta, Munther A

2013-02-01

Antibodies to prothrombin in solid phase (aPT) and those to phosphatidiyserine-prothrombin complex (aPS/PT) have been suggested to strongly correlate with the presence of lupus anticoagulant (LA). As their clinical diagnostic value and true relationship with the LA remains elusive, we designed this study to evaluate the prevalence and significance of aPT and aPS/PT in a large cohort of patients with and without LA. Samples from 257 patients were included. aPT and aPS/PT were tested by ELISA. LA was tested as per the current criteria from the ISTH Subcommittee on LA-Phospholipid-dependent antibodies. aPS/PT and aPT were found in 51% and 32% of LA-positive (LA+ve) patients and in 22% and 28% of LA-negative (LA-ve) patients, respectively. Thrombosis, particularly venous thrombosis was associated with IgG aPT in the LA+ve group (p=0.0006) and in the LA-ve group (p=0.017). Antibodies to phosphatidylserine-prothrombin, either IgG and IgM were associated with thrombosis in general (p=0.0003) in particularly with venous thrombosis in the LA+ve group (paPS/PT were independent risk factors for thrombosis and pregnancy loss. In conclusion, aPS/PT, but not aPT, are more frequently found in patients with LA. Their association with thrombosis seems to be independent of the presence of LA.

Green engineered biomolecule-capped silver and copper nanohybrids using Prosopis cineraria leaf extract: Enhanced antibacterial activity against microbial pathogens of public health relevance and cytotoxicity on human breast cancer cells (MCF-7).

Science.gov (United States)

Jinu, U; Gomathi, M; Saiqa, I; Geetha, N; Benelli, G; Venkatachalam, P

2017-04-01

This research focused on green engineering and characterization of silver (PcAgNPs) and copper nanoparticles (PcCuNPs) using Prosopis cineraria (Pc) leaf extract prepared by using microwave irradiation. We studied their enhanced antimicrobial activity on human pathogens as well as cytotoxicity on breast cancer cells (MCF-7). Biofabricated silver and copper nanoparticles exhibited UV-Visible absorbance peaks at 420 nm and 575 nm, confirming the bioreduction and stabilization of nanoparticles. Nanoparticles were characterized by FTIR, XRD, FESEM, and EDX analysis. FTIR results indicated the presence of alcohols, alkanes, aromatics, phenols, ethers, benzene, amines and amides that were possibly involved in the reduction and capping of silver and copper ions. XRD analysis was performed to confirm the crystalline nature of the silver and copper nanoparticles. FESEM analysis suggested that the nanoparticles were hexagonal or spherical in shape with size ranging from 20 to 44.49 nm and 18.9-32.09 nm for AgNPs and CuNPs, respectively. EDX analysis confirmed the presence of silver and copper elemental signals in the nanoparticles. The bioengineered silver and copper nanohybrids showed enhanced antimicrobial activity against Gram-positive and Gram-negative MDR human pathogens. MTT assay results indicated that CuNPs show potential cytotoxic effect followed by AgNPs against MCF-7 cancer cell line. IC 50 were 65.27 μg/ml, 37.02 μg/ml and 197.3 μg/ml for PcAgNPs, PcCuNPs and P. cineraria leaf extracts, respectively, treated MCF-7 cells. The present investigation highlighted an effective protocol for microwave-assisted synthesis of biomolecule-loaded silver and copper nanoparticles with enhanced antibacterial and anticancer activity. Results strongly suggested that bioengineered AgNPs and CuNPs could be used as potential tools against microbial pathogens and cancer cells. Copyright © 2017 Elsevier Ltd. All rights reserved.

Spectroscopic enhancement in nanoparticles embedded glasses

Energy Technology Data Exchange (ETDEWEB)

Sahar, M. R., E-mail: mrahim057@gmail.com; Ghoshal, S. K., E-mail: mrahim057@gmail.com [Advanced Optical Material Research Group, Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, 81310, Skudai, Johor Bahru, Johor (Malaysia)

2014-09-25

This presentation provides an overview of the recent progress in the enhancement of the spectroscopic characteristics of the glass embedded with nanoparticles (NPs). Some of our research activities with few significantly new results are highlighted and facilely analyzed. The science and technology dealing with the manipulation of the physical properties of rare earth doped inorganic glasses by embedding metallic NPs or nanoclusters produce the so-called 'nanoglass'. Meanwhile, the spectroscopic enhancement relates the intensity of the luminescence measured at certain transition. The enhancement which expectedly due to the 'plasmonics wave' (referring to the coherent coupling of photons to free electron oscillations called plasmon) occurs at the interface between a conductor and a dielectric. Plasmonics being an emerging concept in advanced optical material of nanophotonics has given this material the ability to exploit the optical response at nanoscale and opened up a new avenue in metal-based glass optics. There is a vast array of plasmonic NPs concepts yet to be explored, with applications spanning solar cells, (bio) sensing, communications, lasers, solid-state lighting, waveguides, imaging, optical data transfer, display and even bio-medicine. Localized surface plasmon resonance (LSPR) can enhance the optical response of nanoglass by orders of magnitude as observed. The luminescence enhancement and surface enhanced Raman scattering (SERS) are new paradigm of research. The enhancement of luminescence due to the influence of metallic NPs is the recurring theme of this paper.

Preparation, characterization, and in vitro/vivo studies of oleanolic acid-loaded lactoferrin nanoparticles

Directory of Open Access Journals (Sweden)

Xia X

2017-05-01

Full Text Available Xiaojing Xia,1,2 Haowei Liu,1 Huixia Lv,1 Jing Zhang,1 Jianping Zhou,1 Zhiying Zhao3 1Department of Pharmaceutics, China Pharmaceutical University, Nanjing, 2Department of Pharmaceutics, ZheJiang Pharmaceutical College, Ningbo, 3Department of Traditional Chinese Medicine, China Pharmaceutical University, Nanjing, People’s Republic of China Abstract: Oleanolic acid (OA, a pentacyclic triterpene, is used to safely and economically treat hepatopathy. However, OA, a Biopharmaceutics Classification System IV category drug, has low bioavailability owing to low solubility (<1 µg/mL and biomembrane permeability. We developed a novel OA nanoparticle (OA-NP-loaded lactoferrin (Lf nanodelivery system with enhanced in vitro OA dissolution and improved oral absorption and bioavailability. The OA-NPs were prepared using NP albumin-bound technology and characterized using dynamic light scattering, scanning electron microscopy, X-ray powder diffraction, differential scanning calorimetry, and in vitro dissolution test. The in vivo pharmacokinetics was investigated in Sprague Dawley rats using liquid chromatography-tandem mass spectrometry. OA-NPs (OA:Lf =1:6, w/w% exhibited spherical morphology, 202.2±8.3 nm particle size, +(27.1±0.32 mV ζ potential, 92.59%±3.24% encapsulation efficiency, and desirable in vitro release profiles. An effective in vivo bioavailability (340.59% was achieved compared to the free drug following oral administration to rats. The Lf novel nanodelivery vehicle enhanced the dissolution rate, intestinal absorption, and bioavailability of OA. These results demonstrate that Lf NPs are a new strategy for improving oral absorption and bioavailability of poorly soluble and poorly absorbed drugs. Keywords: oleanolic acid, nanoparticle, lactoferrin nanodelivery system, drug absorption, bioavailability

Effect of AgCl NPs: Physical, thermal, absorption and luminescence properties

Science.gov (United States)

Nurhafizah, H.; Rohani, M. S.

2017-06-01

Silver nanoparticles (AgCl NPs) are embedded in Er3+/Nd3+ co-doped lithium niobate tellurite glasses of the form (68-x)TeO2-15Li2CO3-15Nb2O5-1Er2O3-1Nd2O3-(x)AgCl with x = 1,2 and 3 mol% via conventional melt-quenching technique. The physical properties such as density, ionic packing density, refractive index and electronic polarizability are computed utilizing the usual method. The existence of AgCl NPs with an average size of 3.7 nm is confirmed using TEM analysis. Moreover, the thermal stability and Hruby criterion of the glass decreases as the AgCl NPs content increases. The direct optical band gap are found decrease as the AgCl NPs content increase, but both indirect optical band gap and Urbach energy are found increases as AgCl NPs content increases. The luminescence spectra shows two strong emission which is the purple emission at 436 nm and red emission at 724 nm which also been observed has strong quenching due to the AgCl NPs, Er3+/Nd3+ dopant and modifier, lithium niobate which possessed magnetic penetration. These glass compositions may be potential for various applications such as solid state devices including laser.

Enhanced tumor targeting of cRGD peptide-conjugated albumin nanoparticles in the BxPC-3 cell line.

Science.gov (United States)

Yu, Xinzhe; Song, Yunlong; Di, Yang; He, Hang; Fu, Deliang; Jin, Chen

2016-08-12

The emerging albumin nanoparticle brings new hope for the delivery of antitumor drugs. However, a lack of robust tumor targeting greatly limits its application. In this paper, cyclic arginine-glycine-aspartic-conjugated, gemcitabine-loaded human serum albumin nanoparticles (cRGD-Gem-HSA-NPs) were successfully prepared, characterized, and tested in vitro in the BxPC-3 cell line. Initially, 4-N-myristoyl-gemcitabine (Gem-C14) was formed by conjugating myristoyl to the 4-amino group of gemcitabine. Then, cRGD-HSA was synthesized using sulfosuccinimidyl-(4-N-maleimidomethyl)cyclohexane-1-carboxylate (Sulfo-SMCC) cross-linkers. Finally, cRGD-Gem-HSA-NPs were formulated based on the nanoparticle albumin-bound (nab) technology. The resulting NPs were characterized for particle size, zeta potential, morphology, encapsulation efficiency, and drug loading efficiency. In vitro cellular uptake and inhibition studies were conducted to compare Gem-HSA-NPs and cRGD-Gem-HSA-NPs in a human pancreatic cancer cell line (BxPC-3). The cRGD-Gem-HSA-NPs exhibited an average particle size of 160 ± 23 nm. The encapsulation rate and drug loading rate were approximately 83 ± 5.6% and 11 ± 4.2%, respectively. In vitro, the cRGD-anchored NPs exhibited a significantly greater affinity for the BxPC-3 cells compared to non-targeted NPs and free drug. The cRGD-Gem-HSA-NPs also showed the strongest inhibitory effect in the BxPC-3 cells among all the analyzed groups. The improved efficacy of cRGD-Gem-HSA-NPs in the BxPC-3 cell line warrants further in vivo investigations.

Grading diffuse gliomas without intense contrast enhancement by amide proton transfer MR imaging: comparisons with diffusion- and perfusion-weighted imaging

Energy Technology Data Exchange (ETDEWEB)

Togao, Osamu; Hiwatashi, Akio; Yamashita, Koji; Kikuchi, Kazufumi; Honda, Hiroshi [Kyushu University, Department of Clinical Radiology, Graduate School of Medical Sciences, Fukuoka (Japan); Keupp, Jochen [Philips Research, Hamburg (Germany); Yoshimoto, Koji; Kuga, Daisuke; Iihara, Koji [Kyushu University, Department of Neurosurgery, Graduate School of Medical Sciences, Fukuoka (Japan); Yoneyama, Masami [Philips Electronics Japan, Tokyo (Japan); Suzuki, Satoshi O.; Iwaki, Toru [Kyushu University, Department of Neuropathology, Graduate School of Medical Sciences, Fukuoka (Japan); Takahashi, Masaya [Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, TX (United States)

2017-02-15

To investigate whether amide proton transfer (APT) MR imaging can differentiate high-grade gliomas (HGGs) from low-grade gliomas (LGGs) among gliomas without intense contrast enhancement (CE). This retrospective study evaluated 34 patients (22 males, 12 females; age 36.0 ± 11.3 years) including 20 with LGGs and 14 with HGGs, all scanned on a 3T MR scanner. Only tumours without intense CE were included. Two neuroradiologists independently performed histogram analyses to measure the 90th-percentile (APT{sub 90}) and mean (APT{sub mean}) of the tumours' APT signals. The apparent diffusion coefficient (ADC) and relative cerebral blood volume (rCBV) were also measured. The parameters were compared between the groups with Student's t-test. Diagnostic performance was evaluated with receiver operating characteristic (ROC) analysis. The APT{sub 90} (2.80 ± 0.59 % in LGGs, 3.72 ± 0.89 in HGGs, P = 0.001) and APT{sub mean} (1.87 ± 0.49 % in LGGs, 2.70 ± 0.58 in HGGs, P = 0.0001) were significantly larger in the HGGs compared to the LGGs. The ADC and rCBV values were not significantly different between the groups. Both the APT{sub 90} and APT{sub mean} showed medium diagnostic performance in this discrimination. APT imaging is useful in discriminating HGGs from LGGs among diffuse gliomas without intense CE. (orig.)

Nutlin-3a and Cytokine Co-loaded Spermine-Modified Acetalated Dextran Nanoparticles for Cancer Chemo-Immunotherapy

DEFF Research Database (Denmark)

Bauleth-Ramos, Tomás; Shahbazi, Mohammad-Ali; Liu, Dongfei

2017-01-01

The combination of chemo- and immunotherapy represents one promising strategy to overcome the existent challenges in the present-day anticancer therapy. Here, spermine-modified acetalated dextran nanoparticles (Sp-AcDEX NPs), co-loaded with the non-genotoxic molecule Nutlin-3a (Nut3a), and the cy......The combination of chemo- and immunotherapy represents one promising strategy to overcome the existent challenges in the present-day anticancer therapy. Here, spermine-modified acetalated dextran nanoparticles (Sp-AcDEX NPs), co-loaded with the non-genotoxic molecule Nutlin-3a (Nut3a...

New tests to detect antiphospholipid antibodies: antiprothrombin (aPT) and anti-phosphatidylserine/prothrombin (aPS/PT) antibodies.

Science.gov (United States)

Sciascia, Savino; Khamashta, Munther A; Bertolaccini, Maria Laura

2014-05-01

Antiprothrombin antibodies have been proposed as potential new biomarkers for thrombosis and/or pregnancy morbidity in the setting of the antiphospholipid syndrome (APS). Antiprothrombin antibodies are commonly detected by ELISA, using prothrombin coated onto irradiated plates (aPT), or prothrombin in complex with phosphatidylserine (aPS/PT), as antigen. Although these antibodies can co-exist in the same patient, aPT and aPS/PT seem to belong to different populations of autoantibodies. Early research explored the role of antibodies to prothrombin as potential antigenic targets for the lupus anticoagulant (LA). To date their clinical significance is being investigated and their potential role in identifying patients at higher risk of developing thrombotic events or pregnancy morbidity is being probed.

Biopolymer mediated nanoparticles synthesized from Adenia hondala for enhanced tamoxifen drug delivery in breast cancer cell line

Science.gov (United States)

Varadharajaperumal, Pradeepa; Subramanian, Balakumar; Santhanam, Amutha

2017-09-01

Silver nanoparticles (AgNPs) are an important class of nanomaterials, which have used as antimicrobial and disinfectant agents due to their detrimental effect on target cells. In the present study it was explored to deliver a novel tamoxifen drug system that can be used in breast cancer treatment, based on chitosan coated silver nanoparticles on MCF-7 human breast cancer cells. AgNPs synthesized from Adenia hondala tuber extract were used to make the chitosan coated AgNPs (Ch-AgNPs), in which the drug tamoxifen was loaded on chitosan coated silver nanoparticles (Tam-Ch-AgNPs) to construct drug loaded nanoparticles as drug delivery system. The morphology and characteristics of the Ch-AgNPs were investigated by UV, FTIR, zeta potential and FESEM. Furthermore, the toxicity of AgNPs, Ch-AgNPs, Tam-Ch-AgNPs was evaluated through cell viability, lactate dehydrogenase leakage, reactive oxygen species generation, caspase-3, DNA laddering, and TUNEL assay in human breast cancer cells (MCF-7) and HBL-100 continuous cell line as a control. Treatment of cancer cells with various concentrations of AgNPs, Ch-AgNPs, Tam-Ch-AgNPs for 24 h revealed that Tam-Ch-AgNPs could inhibit cell viability and induce significant membrane leakage in a dose-dependent manner. Cells exposed to Tam-Ch-AgNPs showed increased reactive oxygen species and hydroxyl radical production when compared to AgNPs, Ch-AgNPs. Furthermore, the apoptotic effects of AgNPs, Ch-AgNPs, Tam-Ch-AgNPs were confirmed by activation of caspase-3 and DNA nuclear fragmentation. The present findings suggest that Tam-Ch-AgNPs could contribute to the development of a suitable anticancer drug delivery.

Self-assembled gold nanoparticles modified ITO electrodes: The monolayer binder molecule effect

Energy Technology Data Exchange (ETDEWEB)

Ballarin, Barbara; Cassani, Maria Cristina; Scavetta, Erika; Tonelli, Domenica [Dipartimento di Chimica Fisica ed Inorganica, Universita di Bologna, V.le Risorgimento 4, 40136 Bologna, INSTM, UdR Bologna (Italy)

2008-11-15

The fabrication of gold attached organosilane-coated indium tin oxide Au{sub NPs}-MPTMS/ITO and Au{sub NPs}-APTES/ITO electrodes [MPTMS 3-(mercaptopropyl)-trimethoxysilane, APTES = 3-(aminopropyl)-triethoxysilane, ITO = indium tin oxide] was carried out making use of a well-known two-step procedure and the role played by the -SH and -NH{sub 2} functional groups in the two electrodes has been examined and compared using different techniques. Information about particle coverage and inter-particle spacing has been obtained using transmission electron microscopy (TEM), scanning electron microscopy (SEM) and atomic force microscopy (AFM) whereas, bulk surface properties have been probed with UV-vis spectroscopy, CV and electrochemical impedance spectroscopy (EIS). The catalytic activity of the two electrodes has been evaluated studying the electrooxidation of methanol in alkaline conditions. The results obtained show that the NH{sub 2} functionality in the APTES binder molecule favours the formation of isle-like Au nanoparticle aggregates that lead to both a higher electron transfer and electrocatalytic activity. (author)

Length Matters: Informational Load in Ambiguity Resolution

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Barbara Hemforth

2013-07-01

Full Text Available In this paper, we will compare prosodic and pragmatic approaches to the role of constituent length in attachment ambiguities. Lengthening a constituent affects its informativity: longer constituents are usually less predictable (Levy & Florian, 2007 and demand a higher processing load than shorter ones (Almor, 1999. Following neo-Gricean accounts (Levinson, 1987 and 1991, increased informational load needs to be justified. This justification is achieved more easily when the long constituent conveys new information and when it relates to central elements of the utterance. Informational load is, however, not a simple question of length in numbers of characters or syllables but more likely a question of amount of information. In three off-line experiments using a cloze task, we will compare the effect of lengthening ambiguous prepositional phrases as in [1a/b/c] either by lengthening a city name or by adding information about the city. We will show that only lengthening by adding information increases attachment to a more central element of the utterance. These results will be discussed based on prosodic and pragmatic factors explaining the role of constituent length for attachment ambiguities.[1] Peter met the doctor of the lawyer from a. Apt. / b. Aix-en-Provence / c. the beautiful city of Apt.Dans cet article, nous comparons une approche prosodique avec une approche pragmatique pour rendre compte des effets de la longueur des constituants dans les ambigüités d’attachement. Augmenter la longueur d’un constituant a des conséquences sur l’information qu’il véhicule : plus un constituant est long et moins il est prédictible (Levy et Florian, 2007 et plus son coût de traitement augmente (Almor, 1999. Suivant les principes néo-gricéens (Levinson, 1987 et 1991, augmenter le poids informationnel doit être justifié. Cette justification est plus facilement satisfaite lorsqu’un constituant long véhicule une information

Experimental stress analysis of four machined 10-in. NPS piping elbows with specified geometric distortions

International Nuclear Information System (INIS)

Moore, S.E.; Dodge, W.G.; Bolt, S.E.

1983-09-01

Four specially fabricated nominal 10-in. NPS, 90 0 , long-radius, schedule 40, carbon-steel piping elbows, welded to short lengths of straight pipe, were stress analyzed both experimentally and analytically. One elbow had a circular cross section and a uniform wall thickness, while the other three had either a circular or elliptical cross section with either a uniform or variable wall thickness. The objectives of the tests were primarily to study the influence of out of roundness and wall-thickness variations on the stresses in piping elbows under internal pressure and/or applied moment loadings. Analytical studies were made to isolate the various effects by comparing the experimental data with theoretical baseline solutions. Results of the studies showed that analytical solutions based on no-end-effects (NEE) theory capture the major characteristics of the stress distributions for elbows loaded with pressure and/or in-plane, out-of-plane, or torsional moment loadings. Of the four second-order effects addressed in this study, and effects had the most influence on the stresses, followed in order by out of roundness, wall-thickness variations, and pressure-moment interactions. Of these, the only significant increase in maximum stresses above those predicted by NEE theory was for the case of out of roundness with internal-pressure loading

Synthesis of spindle-shaped AgI/TiO{sub 2} nanoparticles with enhanced photocatalytic performance

Energy Technology Data Exchange (ETDEWEB)

Yang, Liu; Gao, Minggang; Dai, Bin; Guo, Xuhong; Liu, Zhiyong; Peng, Banghua, E-mail: banghuapeng@hotmail.com

2016-11-15

Highlights: • Nanoporous spindle-shaped AgI/TiO{sub 2} was synthesized by the solvothermal approach. • The spindle-shaped TiO{sub 2} was an excellent support for loading nanoparticles, such as AgI, transferring electrons quickly from AgI, which is beneficial for stabilizing the AgI. • AgI/TiO{sub 2} nanoparticles showed enhanced absorption intensity in the visible region and exhibited excellent photocatalytic activity. - Abstract: A novel synthetic route has been developed to prepare silver iodide (AgI) loaded spindle-shaped TiO{sub 2} nanoparticles (NPs). The morphology and crystallinity characterization revealed that small AgI NPs, with an average diameter of 15 nm were dispersed on the surface and interior of nanoporous anatase TiO{sub 2} support. High-resolution transmission electron microscopy (HRTEM), Brunauer-Emmett-Teller (BET) surface area, Raman and X-ray photoelectron spectroscopy (XPS) were used to identify the nanoporous structure of TiO{sub 2} and the existence of AgI NPs. Diffuse reflectance spectra (DRS) showed that AgI/TiO{sub 2} composite exhibited a remarkable enhancement of visible light absorption, which is ascribed to the addition of AgI. For illustrating the superior property of this hybrid as photocatalyst, the degradation experiments were carried out for processing rhodamine B (RhB) solution under visible light irradiation and it was found that the photocatalytic activity was dramatically improved for AgI/TiO{sub 2} compared with nanoporous TiO{sub 2} and commercial P25 TiO{sub 2}. The enhanced photocatalytic properties could be attributed to the large surface area of porous TiO{sub 2}, good stability of AgI particles, and the effective charge separation due to the synergetic effect between AgI and TiO{sub 2} that can facilitate the separation of electron-hole pairs. Our novel composite based on nanoporous spindle-shaped TiO{sub 2} represents a promising new pathway for the design of high-performance photocatalysts for environmental

Micah 1, an apt introduction to power talks

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W.J. Wessels

1998-08-01

Full Text Available Power and the abuse of it, is often an integral part of discussions in any society. The prophets of the Old Testament felt strongly about this issue and often spoke out against the abuse of power and the suffering caused by it. Micah particularly addresses this issue in chapters 2 and 3. He blames the leaders in society, who should look out for the ordinary people, that they in particular are guilty of this transgression. In chapter 1 Micah proclaims Yahweh as the sovereign power who they should take note off. On the very basis of Yahweh's sovereign power he then proclaims oracles of judgment on the people of Judah. Micah 1 seems to form an apt introduction to the talks of the abuse of power in the society of Judah.

NPS-SCAT; Communications System Design, Test and Integration of NPS’ First CubeSat

Science.gov (United States)

2010-09-01

Batteries..........27  Figure 17.  Temperature Sensors.............................28  Figure 18.  Pumpkin FM430 Flight Module.....................29...system, which used spread spectrum techniques within the UHF amateur band. On a historical day for NPS, October 29, 1998, PANSAT was launched from... spread -spectrum mode of PANSAT used for the messaging system: spacecraft command and control was accomplished with a narrow 78.1 kbps channel that

Antifungal Effects of Silver Nanoparticles (AgNPs) against Various Plant Pathogenic Fungi.

Science.gov (United States)

Kim, Sang Woo; Jung, Jin Hee; Lamsal, Kabir; Kim, Yun Seok; Min, Ji Seon; Lee, Youn Su

2012-03-01

This research is concerned with the fungicidal properties of nano-size silver colloidal solution used as an agent for antifungal treatment of various plant pathogens. We used WA-CV-WA13B, WA-AT-WB13R, and WA-PR-WB13R silver nanoparticles (AgNPs) at concentrations of 10, 25, 50, and 100 ppm. Eighteen different plant pathogenic fungi were treated with these AgNPs on potato dextrose agar (PDA), malt extract agar, and corn meal agar plates. We calculated fungal inhibition in order to evaluate the antifungal efficacy of silver nanoparticles against pathogens. The results indicated that AgNPs possess antifungal properties against these plant pathogens at various levels. Treatment with WA-CV-WB13R AgNPs resulted in maximum inhibition of most fungi. Results also showed that the most significant inhibition of plant pathogenic fungi was observed on PDA and 100 ppm of AgNPs.

Translocation of SiO2-NPs across in vitro human bronchial epithelial monolayer

International Nuclear Information System (INIS)

George, I; Vranic, S; Boland, S; Borot, M C; Marano, F; Baeza-Squiban, A

2013-01-01

Safe development and application of nanotechnologies in many fields require better knowledge about their potential adverse effects on human health. Evidence of abilities of nanoparticles (NPs) to cross epithelial barriers and reach secondary organs via the bloodstream led us to investigate the translocation of SiO 2 NPs of 50 nm (50 nm-SiO 2 -NPs) across human bronchial epithelial cells that are primary targets after exposure to inhaled NPs. We quantified the translocation of fluorescently labelled SiO 2 NPs at non-cytotoxic concentrations (5 and 10 μg/cm 2 ) across Calu-3 epithelial monolayer. After 14 days in culture Calu-3 cells seeded onto 3 μm-polycarbonate Transwell membranes formed an efficient bronchial barrier assessed by measurement of the transepithelial electric resistance and quantification of the permeability of the monolayer. After 24 hours of exposure, we observed a significant translocation of NPs that was more important when the initial NP concentration decreased. Confocal microscopy observations revealed NP uptake by cells and an important NP retention inside the porous membrane. In conclusion, 50 nm-SiO 2 -NPs can cross the human bronchial epithelial barrier without affecting the integrity of the epithelial cell monolayer.

Biosynthesis and Characterization of AgNPs-Silk/PVA Film for Potential Packaging Application.

Science.gov (United States)

Tao, Gang; Cai, Rui; Wang, Yejing; Song, Kai; Guo, Pengchao; Zhao, Ping; Zuo, Hua; He, Huawei

2017-06-17

Bionanocomposite packaging materials have a bright future for a broad range of applications in the food and biomedical industries. Antimicrobial packaging is one of the bionanocomposite packaging materials. Silver nanoparticle (AgNP) is one of the most attractive antimicrobial agents for its broad spectrum of antimicrobial activity against microorganisms. However, the traditional method of preparing AgNPs-functionalized packaging material is cumbersome and not environmentally friendly. To develop an efficient and convenient biosynthesis method to prepare AgNPs-modified bionanocomposite material for packaging applications, we synthesized AgNPs in situ in a silk fibroin solution via the reduction of Ag⁺ by the tyrosine residue of fibroin, and then prepared AgNPs-silk/poly(vinyl alcohol) (PVA) composite film by blending with PVA. AgNPs were synthesized evenly on the surface or embedded in the interior of silk/PVA film. The prepared AgNPs-silk/PVA film exhibited excellent mechanical performance and stability, as well as good antibacterial activity against both Gram-negative and Gram-positive bacteria. AgNPs-silk/PVA film offers more choices to be potentially applied in the active packaging field.

APTES-Terminated ultrasmall and iron-doped silicon nanoparticles as X-Ray dose enhancer for radiation therapy.

Science.gov (United States)

Klein, Stefanie; Wegmann, Marc; Distel, Luitpold V R; Neuhuber, Winfried; Kryschi, Carola

2018-04-15

Silicon nanoparticles with sizes between were synthesized through wet-chemistry procedures using diverse phase transfer reagents. On the other hand, the preparation of iron-doped silicon nanoparticles was carried out using the precursor Na 4 Si 4 containing 5% Fe. Biocompatibility of all silicon nanoparticle samples was achieved by surface-stabilizing with (3-aminopropyl)triethoxysilane. These surface structures provided positive surface charges which facilitated electrostatic binding to the negatively charged biological membranes. The mode of interaction with membranes, being either incorporation or just attachment, was found to depend on the nanoparticle size. The smallest silicon nanoparticles (ca. 1.5 nm) were embedded in the mitochondrial membrane in MCF-7 cells. When interacting with X-rays these silicon nanoparticles were observed to enhance the superoxide formation upon depolarizing the mitochondrial membrane. X-ray irradiation of MCF-7 cells loaded with the larger silicon nanoparticles was shown to increase the intracellular singlet oxygen generation. The doping of the silicon nanoparticles with iron led to additional production of hydroxyl radicals via the Fenton reaction. Copyright © 2018 Elsevier Inc. All rights reserved.

Novel dipeptide nanoparticles for effective curcumin delivery

Science.gov (United States)

Alam, Shadab; Panda, Jiban J; Chauhan, Virander S

2012-01-01

Background: Curcumin, the principal curcuminoid of the popular Indian spice turmeric, has a wide spectrum of pharmaceutical properties such as antitumor, antioxidant, antiamyloid, and anti-inflammatory activity. However, poor aqueous solubility and low bioavailability of curcumin is a major challenge in its development as a useful drug. To enhance the aqueous solubility and bioavailability of curcumin, attempts have been made to encapsulate it in liposomes, polymeric nanoparticles (NPs), lipid-based NPs, biodegradable microspheres, cyclodextrin, and hydrogels. Methods: In this work, we attempted to entrap curcumin in novel self-assembled dipeptide NPs containing a nonprotein amino acid, α, β-dehydrophenylalanine, and investigated the biological activity of dipeptide-curcumin NPs in cancer models both in vitro and in vivo. Results: Of the several dehydrodipeptides tested, methionine-dehydrophenylalanine was the most suitable one for loading and release of curcumin. Loading of curcumin in the dipeptide NPs increased its solubility, improved cellular availability, enhanced its toxicity towards different cancerous cell lines, and enhanced curcumin’s efficacy towards inhibiting tumor growth in Balb/c mice bearing a B6F10 melanoma tumor. Conclusion: These novel, highly biocompatible, and easy to construct dipeptide NPs with a capacity to load and release curcumin in a sustained manner significantly improved curcumin’s cellular uptake without altering its anticancer or other therapeutic properties. Curcumin-dipeptide NPs also showed improved in vitro and in vivo chemotherapeutic efficacy compared to curcumin alone. Such dipeptide-NPs may also improve the delivery of other potent hydrophobic drug molecules that show poor cellular uptake, bioavailability, and efficacy. PMID:22915849

Assessment of copper nanoparticles (Cu-NPs) and copper (II) oxide (CuO) induced hemato- and hepatotoxicity in Cyprinus carpio

Science.gov (United States)

Noureen, Aasma; Jabeen, Farhat; Tabish, Tanveer A.; Yaqub, Sajid; Ali, Muhammad; Shakoor Chaudhry, Abdul

2018-04-01

Recently, Cu-based nanoparticles have drawn considerable attention for their various fascinating roles in multiple biological systems. It is recognized that their frequent use can create compatibility challenges for the recipient systems. Nevertheless, it is unclear how various biological interactions affect the compatibility of Cu oxide II (CuO) and Cu oxide nanoparticles (Cu-NPs) for different organisms. Consequently, it has been difficult to perform structured risk assessments for their use in biological systems. Therefore, this study compared the effects of different doses of waterborne Cu-NPs and CuO on the blood and liver of selected groups of Cyprinus (C) carpio. These fish while housed in suitable water tanks were exposed to one of the following treatments for 14 d: control (no added Cu) or 0.5 or 1 or 1.5 mg Cu as Cu-NPs or CuO l-1 of water. We found significant changes in all assessed blood parameters of fish in response to increasing doses from 0 to 1.5 mg of Cu-NPs or CuO. Similarly, increased levels of lipid peroxide and reduced glutathione (GSH) were also observed in the livers of C. carpio in Cu-NPs or CuO treated groups. Enhanced levels of lipid peroxidation and GSH were also recorded in the Cu-NP treated groups compared with the CuO treated groups in a dose dependent manner. The lowest catalase activity was observed in the liver of C. carpio treated with the higer dose of Cu-NPs. Cu-NP or CuO exposure induced significant histological alterations in the liver of C. carpio including focal necrosis, cloudy swelling of hepatocytes, degenerative hepatocytes, vacuolization, pyknotic nuclei, damaged central vein, nuclear hypertrophy, dilated sinusoid, vacuolated degeneration, congestion, and complete degeneration in a dose dependent manner. Substantial alterations in blood and liver specimens were observed in the Cu-NP treated fish when compared with the CuO treated fish. It appeared that the Cu-NPs were more toxic than the CuO as shown by the hemato- and

Multifunctional AgNPs@Wool: colored, UV-protective and antioxidant functional textiles

Science.gov (United States)

Shabbir, Mohd; Mohammad, Faqeer

2018-02-01

Nanomaterials have great impact on textile industry for multifunctional and smart clothing as per the need of present, and further, green nanotechnology is the current hotspot of research and industrial developments. Silver nanoparticles (AgNPs) are synthesized (in situ) by using natural compounds of plant extracts (naphthoquinones, phenolics/flavonoids, polyphenols) as reducing or stabilizing agents, and simultaneously deposited on wool fabric for coloration, UV protection and antioxidant properties. UV-visible spectroscopy is used to monitor the route of biosynthesis of nanoparticles and transmission electron microscopy for morphological characteristics of synthesized AgNPs. Spherical and almost oval-shaped AgNPs were synthesized by naphthoquinones, polyphenols and flavonoids, respectively. Scanning electron microscopy (SEM) coupled with energy dispersive X-ray (EDX) spectroscopy, X-ray diffraction pattern (XRD) and Fourier transform infrared spectroscopy were used for the AgNPs@Wool fabrics characterization. SEM-EDX analysis and XRD patterns confirmed the successful deposition of silver nanoparticles on wool. Coloration characteristics in terms of color strength (K/S) and CIEL*a*b*c*h° values, UV protection abilities in terms of UV transmittance and UV protection factor, and % antioxidant activity of AgNPs@Wool are suggestive of good-to-excellent results.

The NPs Role of Assessing and Intervening with Older Adult Drivers

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Tamatha Arms

2016-01-01

Full Text Available As the silver tsunami continues, assessing and intervening with older adult drivers are becoming an essential aspect of the comprehensive geriatric exam. The current lack of time efficient clinical guidelines is a concern and barrier for NPs. The purpose of this study was to identify strategies currently used by NPs. The critical incident technique was used to obtain data from a convenience sample of NPs. A total of 89 incidents were collected. The perspective of the NP can provide important information for developing clinical guidelines to promote individual and community safety.

Cabazitaxel-loaded human serum albumin nanoparticles as a therapeutic agent against prostate cancer

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Qu N

2016-07-01

Full Text Available Na Qu,1 Robert J Lee,1,2 Yating Sun,1 Guangsheng Cai,1 Junyang Wang,1 Mengqiao Wang,1 Jiahui Lu,1 Qingfan Meng,1 Lirong Teng,1 Di Wang,1 Lesheng Teng1,3 1School of Life Sciences, Jilin University, Changchun, People’s Republic of China; 2Division of Pharmaceutics, College of Pharmacy, The Ohio State University, Columbus, OH, USA; 3State Key Laboratory of Long-acting and Targeting Drug Delivery System, Yantai, People’s Republic of China Abstract: Cabazitaxel-loaded human serum albumin nanoparticles (Cbz-NPs were synthesized to overcome vehicle-related toxicity of current clinical formulation of the drug based on Tween-80 (Cbz-Tween. A salting-out method was used for NP synthesis that avoids the use of chlorinated organic solvent and is simpler compared to the methods based on emulsion-solvent evaporation. Cbz-NPs had a narrow particle size distribution, suitable drug loading content (4.9%, and superior blood biocompatibility based on in vitro hemolysis assay. Blood circulation, tumor uptake, and antitumor activity of Cbz-NPs were assessed in prostatic cancer xenograft-bearing nude mice. Cbz-NPs exhibited prolonged blood circulation and greater accumulation of Cbz in tumors along with reduced toxicity compared to Cbz-Tween. Moreover, hematoxylin and eosin histopathological staining of organs revealed consistent results. The levels of blood urea nitrogen and serum creatinine in drug-treated mice showed that Cbz-NPs were less toxic than Cbz-Tween to the kidneys. In conclusion, Cbz-NPs provide a promising therapeutic for prostate cancer. Keywords: cabazitaxel, human serum albumin, nanoparticle, drug delivery, toxicity, pros­tate cancer

Folate attached, curcumin loaded Fe_3O_4 nanoparticles: A novel multifunctional drug delivery system for cancer treatment

International Nuclear Information System (INIS)

Thu Huong, Le Thi; Nam, Nguyen Hoai; Doan, Do Hai; My Nhung, Hoang Thi; Quang, Bui Thuc; Nam, Pham Hong; Thong, Phan Quoc; Phuc, Nguyen Xuan; Thu, Ha Phuong

2016-01-01

Study and development of drug delivery nanosystem for cancer treatment are attracting great attention in recent years. In this work, we studied the role of folic acid as a targeting factor on magnetic nanoparticle Fe_3O_4 based curcumin loading nanosystem. Characteristics of the nanosystems were investigated by Fourier transform infrared spectroscopy (FTIR) and field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), thermal gravimetric analysis (TGA) and vibrating sample magnetometer (VSM), while targeting role of folic was accessed in vivo on tumor bearing mice. The results showed that folate attached Fe_3O_4 based curcumin loading nanosystem has very small size and exhibits better targeting effect compared to the counterpart without folate. In addition, magnetic induction heating of this nanosystem evidenced its potential for cancer hyperthermia. - Highlights: • Folate attached, curcumin loaded Fe3O4 nanoparticles were prepared and characterized. • The NPs have high curcumin loading capacity and good ability for hyperthermia. • Folate shows its bioactivity of effectively targeting the NPs to tumor tissues. • Chemotherapy, hyperthermia and targeting factor are all well combined in the NPs.

Polyethylenimine-mediated synthetic insertion of gold nanoparticles into mesoporous silica nanoparticles for drug loading and biocatalysis.

Science.gov (United States)

Pandey, Prem C; Pandey, Govind; Narayan, Roger J

2017-03-27

Mesoporous silica nanoparticles (MSNPs) have been used as an efficient and safe carrier for drug delivery and biocatalysis. The surface modification of MSNPs using suitable reagents may provide a robust framework in which two or more components can be incorporated to give multifunctional capabilities (e.g., synthesis of noble metal nanoparticles within mesoporous architecture along with loading of a bioactive molecule). In this study, the authors reported on a new synthetic route for the synthesis of gold nanoparticles (AuNPs) within (1) unmodified MSNPs and (2) 3-trihydroxysilylpropyl methylphosphonate-modified MSNPs. A cationic polymer, polyethylenimine (PEI), and formaldehyde were used to mediate synthetic incorporation of AuNPs within MSNPs. The AuNPs incorporated within the mesoporous matrix were characterized by transmission electron microscopy, energy dispersive x-ray analysis, and high-resolution scanning electron microscopy. PEI in the presence of formaldehyde enabled synthetic incorporation of AuNPs in both unmodified and modified MSNPs. The use of unmodified MSNPs was associated with an increase in the polycrystalline structure of the AuNPs within the MSNPs. The AuNPs within modified MSNPs showed better catalytic activity than those within unmodified MSNPs. MSNPs with an average size of 200 nm and with a pore size of 4-6 nm were used for synthetic insertion of AuNPs. It was found that the PEI coating enabled AuNPs synthesis within the mesopores in the presence of formaldehyde or tetrahydrofuran hydroperoxide at a temperature between 10 and 25 °C or at 60 °C in the absence of organic reducing agents. The as-made AuNP-inserted MSNPs exhibited enhanced catalytic activity. For example, these materials enabled rapid catalytic oxidation of the o-dianisidine substrate to produce a colored solution in proportion to the amount of H 2 O 2 generated as a function of glucose oxidase-catalyzed oxidation of glucose; a linear concentration range from 80 to

Local anesthetic effects of bupivacaine loaded lipid-polymer hybrid nanoparticles: In vitro and in vivo evaluation.

Science.gov (United States)

Ma, Pengju; Li, Ting; Xing, Huaixin; Wang, Suzhen; Sun, Yingui; Sheng, Xiugui; Wang, Kaiguo

2017-05-01

There is a compelling need for prolonged local anesthetic that would be used for analgesia with a single administration. However, due to the low molecular weight of local anesthetics (LA) (lidocaine, bupivacaine, procaine, dibucaine, etc), they present fast systemic absorption. The aim of the present study was to develop and evaluate bupivacaine lipid-polymer hybrid nanoparticles (BVC LPNs), and compared with BVC loaded PLGA nanoparticles (BVC NPs). Their morphology, particle size, zeta potential and drug loading capacity were evaluated. In vitro release study, stability and cytotoxicity were studied. In vivo evaluation of anesthetic effects was performed on animal models. A facile nanoprecipitation and self-assembly method was optimized to obtain BVC LPNs, composed of PLGA, lecithin and DSPE-PEG 2000 , of ∼175nm particle size. Compared to BVC NPs, BVC LPNs exhibited prolonged in vitro release in phosphate-buffered saline (pH=7.4). Further, BVC LPNs displayed enhanced in vitro stability in 10% FBS and lower cytotoxicity (the concentration of BVC ranging from 1.0μM to 20μM). In addition, BVC LPNs exhibited significantly prolonged analgesic duration. These results demonstrate that the LPNs could function as promising drug delivery system for overcoming the drawbacks of poor stability and rapid drug leakage, and prolonging the anesthetic effect with slight toxicity. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Leveraging the NPS Femto Satellite for Alternative Satellite Communication Networks

Science.gov (United States)

2017-09-01

programmed for eventual integration with the Iridium Network , which is then tested. C. THESIS ORGANIZATION The thesis addresses these questions...NPS FEMTO SATELLITE FOR ALTERNATIVE SATELLITE COMMUNICATION NETWORKS by Faisal S. Alshaya September 2017 Co-Advisors: Steven J. Iatrou...TYPE AND DATES COVERED Master’s thesis 4. TITLE AND SUBTITLE LEVERAGING THE NPS FEMTO SATELLITE FOR ALTERNATIVE SATELLITE COMMUNICATION NETWORKS 5

NaNO3/NaCl Oxidant and Polyethylene Glycol (PEG) Capped Gold Nanoparticles (AuNPs) as a Novel Green Route for AuNPs Detection in Electrochemical Biosensors.

Science.gov (United States)

López-Marzo, Adaris M; Hoyos-de-la-Torre, Raquel; Baldrich, Eva

2018-03-20

Gold nanoparticles (AuNPs) have been exploited as signal-producing tags in electrochemical biosensors. However, the electrochemical detection of AuNPs is currently performed using corrosive acid solutions, which may raise health and environmental concerns. Here, oxidant salts, and specifically the environmentally friendly and occupational safe NaNO 3 /NaCl mixture, have been evaluated for the first time as potential alternatives to the acid solutions traditionally used for AuNPs electrooxidation. In addition, a new strategy to improve the sensitivity of the biosensor through PEG-based ligand exchange to produce less compact and easier to oxidize AuNPs immunoconjugates is presented too. As we show, the electrochemical immunosensor using NaNO 3 /NaCl measurement solution for AuNPs electrooxidation and detection, coupled to the employment of PEG-capped nanoimmunoconjugates, produced results comparable to classical HCl detection. The procedure developed was next tested for human matrix metallopeptidase-9 (hMMP9) analysis, exhibiting a 0.18-23 ng/mL linear range, a detection limit of 0.06 ng/mL, and recoveries between 95 and 105% in spiked human plasma. These results show that the procedure developed is applicable to the analysis of protein biomarkers in blood plasma and could contribute to the development of more environmentally friendly AuNP-based electrochemical biosensors.

Enhanced Sucrose Loading Improves Rice Yield by Increasing Grain Size.

Science.gov (United States)

Wang, Liang; Lu, Qingtao; Wen, Xiaogang; Lu, Congming

2015-12-01

Yield in cereals is a function of grain number and size. Sucrose (Suc), the main carbohydrate product of photosynthesis in higher plants, is transported long distances from source leaves to sink organs such as seeds and roots. Here, we report that transgenic rice plants (Oryza sativa) expressing the Arabidopsis (Arabidopsis thaliana) phloem-specific Suc transporter (AtSUC2), which loads Suc into the phloem under control of the phloem protein2 promoter (pPP2), showed an increase in grain yield of up to 16% relative to wild-type plants in field trials. Compared with wild-type plants, pPP2::AtSUC2 plants had larger spikelet hulls and larger and heavier grains. Grain filling was accelerated in the transgenic plants, and more photoassimilate was transported from the leaves to the grain. In addition, microarray analyses revealed that carbohydrate, amino acid, and lipid metabolism was enhanced in the leaves and grain of pPP2::AtSUC2 plants. Thus, enhancing Suc loading represents a promising strategy to improve rice yield to feed the global population. © 2015 American Society of Plant Biologists. All Rights Reserved.

TAF11 assembles RISC loading complex to enhance RNAi efficiency

Science.gov (United States)

Liang, Chunyang; Wang, Yibing; Murota, Yukiko; Liu, Xiang; Smith, Dean; Siomi, Mikiko C.; Liu, Qinghua

2015-01-01

SUMMARY Assembly of the RNA-induced silencing complex (RISC) requires formation of the RISC loading complex (RLC), which contains Dicer-2(Dcr-2)-R2D2 complex and recruits duplex siRNA to Ago2 in Drosophila melanogaster. However, the precise composition and action mechanism of Drosophila RLC remain unclear. Here, we identified the missing factor of RLC as TATA-binding protein associated factor 11 (TAF11) by genetic screen. Although an annotated nuclear transcription factor, we found that TAF11 also associated with Dcr-2/R2D2 and localized to cytoplasmic D2 bodies. Consistent with defective RLC assembly in taf11−/− ovary extract, we reconstituted the RLC in vitro using recombinant Dcr-2-R2D2 complex, TAF11, and duplex siRNA. Furthermore, we showed that TAF11 tetramer facilitates Dcr-2-R2D2 tetramerization to enhance siRNA binding and RISC loading activities. Together, our genetic and biochemical studies define the molecular nature of Drosophila RLC and elucidate a novel cytoplasmic function of TAF11 in organizing RLC assembly to enhance RNAi efficiency. PMID:26257286

Neuronal uptake and neuroprotective effect of curcumin-loaded PLGA nanoparticles on the human SK-N-SH cell line.

Science.gov (United States)

Doggui, Sihem; Sahni, Jasjeet Kaur; Arseneault, Madeleine; Dao, Lé; Ramassamy, Charles

2012-01-01

Curcumin, a natural polyphenolic pigment present in the spice turmeric (Curcuma longa), is known to possess a pleiotropic activity such as antioxidant, anti-inflammatory, and anti-amyloid-β activities. However, these benefits of curcumin are limited by its poor aqueous solubility and oral bioavailability. In the present study, a polymer-based nanoparticle approach has been utilized to deliver drugs to neuronal cells. Curcumin was encapsulated in biodegradable poly (lactide-co-glycolide) (PLGA) based-nanoparticulate formulation (Nps-Cur). Dynamic laser light scattering and transmission electronic microscopy analysis indicated a particle diameter ranging from 80 to 120 nm. The entrapment efficiency was 31% with 15% drug-loading. In vitro release kinetics of curcumin from Nps-Cur revealed a biphasic pattern with an initial exponential phase followed by a slow release phase. Cellular internalization of Nps-Cur was confirmed by fluorescence and confocal microscopy with a wide distribution of the fluorescence in the cytoplasm and within the nucleus. The prepared nanoformulation was characterized for cellular toxicity and biological activity. Cytotoxicity assays showed that void PLGA-nanoparticles (Nps) and curcumin-loaded PLGA nanoparticles (Nps-Cur) were nontoxic to human neuroblastoma SK-N-SH cells. Moreover, Nps-Cur was able to protect SK-N-SH cells against H2O2 and prevent the elevation of reactive oxygen species and the consumption of glutathione induced by H2O2. Interestingly, Nps-Cur was also able to prevent the induction of the redox-sensitive transcription factor Nrf2 in the presence of H2O2. Taken together, these results suggest that Nps-Cur could be a promising drug delivery strategy to protect neurons against oxidative damage as observed in Alzheimer's disease.

Ciprofloxacin-loaded PLGA nanoparticles against Cystic Fibrosis P. aeruginosa Lung Infections.

OpenAIRE

Günday Türeli, Nazende; Torge, Afra; Juntke, Jenny; Schwarz, Bianca C; Schneider-Daum, Nicole; Türeli, Akif Emre; Lehr, Claus-Michael; Schneider, Marc

2017-01-01

Current pulmonary treatments against Pseudomonasaeruginosa infections in cystic fibrosis (CF) lung suffer from deactivation of the drug and immobilization in thick and viscous biofilm/mucus blend, along with the general antibiotic resistance. Administration of nanoparticles (NPs) with high antibiotic load capable of penetrating the tight mesh of biofilm/mucus can be an advent to overcome the treatment bottlenecks. Biodegradable and biocompatible polymer nanoparticles efficiently loaded with c...

Dairy Streptococcus thermophilus improves cell viability of Lactobacillus brevis NPS-QW-145 and its γ-aminobutyric acid biosynthesis ability in milk

Science.gov (United States)

Wu, Qinglong; Law, Yee-Song; Shah, Nagendra P.

2015-01-01

Most high γ-aminobutyric acid (GABA) producers are Lactobacillus brevis of plant origin, which may be not able to ferment milk well due to its poor proteolytic nature as evidenced by the absence of genes encoding extracellular proteinases in its genome. In the present study, two glutamic acid decarboxylase (GAD) genes, gadA and gadB, were found in high GABA-producing L. brevis NPS-QW-145. Co-culturing of this organism with conventional dairy starters was carried out to manufacture GABA-rich fermented milk. It was observed that all the selected strains of Streptococcus thermophilus, but not Lactobacillus delbrueckii subsp. bulgaricus, improved the viability of L. brevis NPS-QW-145 in milk. Only certain strains of S. thermophilus improved the gadA mRNA level in L. brevis NPS-QW-145, thus enhanced GABA biosynthesis by the latter. These results suggest that certain S. thermophilus strains are highly recommended to co-culture with high GABA producer for manufacturing GABA-rich fermented milk. PMID:26245488

Dairy Streptococcus thermophilus improves cell viability of Lactobacillus brevis NPS-QW-145 and its γ-aminobutyric acid biosynthesis ability in milk.

Science.gov (United States)

Wu, Qinglong; Law, Yee-Song; Shah, Nagendra P

2015-08-06

Most high γ-aminobutyric acid (GABA) producers are Lactobacillus brevis of plant origin, which may be not able to ferment milk well due to its poor proteolytic nature as evidenced by the absence of genes encoding extracellular proteinases in its genome. In the present study, two glutamic acid decarboxylase (GAD) genes, gadA and gadB, were found in high GABA-producing L. brevis NPS-QW-145. Co-culturing of this organism with conventional dairy starters was carried out to manufacture GABA-rich fermented milk. It was observed that all the selected strains of Streptococcus thermophilus, but not Lactobacillus delbrueckii subsp. bulgaricus, improved the viability of L. brevis NPS-QW-145 in milk. Only certain strains of S. thermophilus improved the gadA mRNA level in L. brevis NPS-QW-145, thus enhanced GABA biosynthesis by the latter. These results suggest that certain S. thermophilus strains are highly recommended to co-culture with high GABA producer for manufacturing GABA-rich fermented milk.

CMAQ and NPS : exploring the applicability of the Congestion Mitigation and Air Quality Improvement program to NPS transit

Science.gov (United States)

2014-03-06

The Congestion Mitigation and Air Quality Improvement (CMAQ) Program is a funding program that was most recently : re-authorized in Moving Ahead for Progress in the 21st Century. CMAQ offers a potential funding opportunity for NPS park units : with e...

An efficient Trojan delivery of tetrandrine by poly(N-vinylpyrrolidone-block-poly(ε-caprolactone (PVP-b-PCL nanoparticles shows enhanced apoptotic induction of lung cancer cells and inhibition of its migration and invasion

Directory of Open Access Journals (Sweden)

Xu H

2013-12-01

Full Text Available Huae Xu,1,2 Zhibo Hou,3 Hao Zhang,4 Hui Kong,2 Xiaolin Li,4 Hong Wang,2 Weiping Xie21Department of Pharmacy, 2Department of Respiratory Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, People's Republic of China; 3First Department of Respiratory Medicine, Nanjing Chest Hospital, Nanjing, People's Republic of China; 4Department of Geriatric Gastroenterology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, People's Republic of ChinaAbstract: Earlier studies have demonstrated the promising antitumor effect of tetrandrine (Tet against a series of cancers. However, the poor solubility of Tet limits its application, while its hydrophobicity makes Tet a potential model drug for nanodelivery systems. We report on a simple way of preparing drug-loaded nanoparticles formed by amphiphilic poly(N-vinylpyrrolidone-block-poly(ε-caprolactone (PVP-b-PCL copolymers with Tet as a model drug. The mean diameters of Tet-loaded PVP-b-PCL nanoparticles (Tet-NPs were between 110 nm and 125 nm with a negative zeta potential slightly below 0 mV. Tet was incorporated into PVP-b-PCL nanoparticles with high loading efficiency. Different feeding ratios showed different influences on sizes, zeta potentials, and the drug loading efficiencies of Tet-NPs. An in vitro release study shows the sustained release pattern of Tet-NPs. It is shown that the uptake of Tet-NPs is mainly mediated by the endocytosis of nanoparticles, which is more efficient than the filtration of free Tet. Further experiments including fluorescence activated cell sorting and Western blotting indicated that this Trojan strategy of delivering Tet in PVP-b-PCL nanoparticles via endocytosis leads to enhanced induction of apoptosis in the non-small cell lung cancer cell A549 line; enhanced apoptosis is achieved by inhibiting the expression of anti-apoptotic Bcl-2 and Bcl-xL proteins. Moreover, Tet-NPs more efficiently inhibit the ability of cell migration and

Structural mechanical and antibacterial properties of HPMC/SF-AgNPs nanocomposite films

Science.gov (United States)

Harish, K. V.; Rao, B. Lakshmeesha; Asha, S.; Vipin, C.; Sangappa, Y.

2018-04-01

In the present study, Hydroxypropyl Methylcellulose (HPMC) pure and HPMC/SF-AgNPs biopolymer nanocomposite films were prepared by simple solution casting method. The prepared nanocomposite films were characterized using UV-Visible spectroscopy(UV-Vis), X-ray diffraction (XRD) measurements. The mechanical properties of HPMC/SF-AgNPs nanocomposites were found to be decrease with increase in the AgNP's concentrations. The HPMC/SF-AgNPs nanocomposites showed very good antibacterial activity against human pathogens P. aeruginosa, E.coli, and S.aureus.

Selective colorimetric sensors based on the monitoring of an unmodified silver nanoparticles (AgNPs) reduction for a simple and rapid determination of mercury

Science.gov (United States)

Jarujamrus, Purim; Amatatongchai, Maliwan; Thima, Araya; Khongrangdee, Thatsanee; Mongkontong, Chakrit

2015-05-01

In this work, selective colorimetric sensors for simple and rapid detection of Hg(II) ions based on the monitoring of an unmodified silver nanoparticles (AgNPs) reduction were developed. The average diameter of synthesized AgNPs was 8.3 ± 1.4 nm which was characterized by transmission electron microscopy (TEM). The abrupt change in absorbance of the unmodified AgNPs was observed which progressively decreased and slightly shifted to the blue wavelength as the concentration of Hg(II) increased, indicating the oxidation of Ag(0) to Ag(I) occurred. It appears that the AgNPs were oxidized by Hg(II), resulting in disintegration of the AgNPs into smaller particles as well as mediating the reduction of Hg(II) to Hg(0) adsorbed onto the surface of AgNPs. The adsorption of Hg(0) resulted in the lack of sufficient charges on AgNPs surfaces due to the decrease in the surface coverage of negatively charged citrate molecules, which then leaded to enlargement of AgNPs. The calibration curve of this technique was demonstrated from 0.5 to 7 ppm (r2 = 0.995), the limit of detection (LOD) was 0.06 ppm (SDblank/slope of calibration curve) with the precision (RSD, n = 4) of 3.24-4.53. Interestingly, the results show a significant enhance in the Hg(II) analytical sensitivity when Cu(II) is doped onto the unmodified AgNPs, which improves the quantitative detection limit to 0.008 ppm. In addition, greater selectivity toward Hg(II) compared with the other metal ions tested was observed. Furthermore, the percentage recoveries of spiked drinking water, tap water and SRM1641d (mercury in water) were in acceptable range with a good precision (RSD) which were in agreement with the values obtained from graphite furnace atomic absorption spectrometer (GFAAS). The technique proposed in this study provides a rapid, simple, sensitive and selective detection method for Hg(II) in water samples.

NPS-SCAT: Electrical Power System

Science.gov (United States)

2009-09-01

Postgraduate School thesis, 2009. 5 M.P. Schroer, NPS-SCAT; A Cubesat Communications System Design, Test, and Intergration . Monterey: Naval...AIAA, 2007. 9 production of the 2400 unit. Communication testing of the 2420 unit initially showed great promise. Data rates that would easily...After a review of available products , the Clyde Space EPS was selected based on three major considerations. One, the Clyde Space unit had been flown on

Novel functionalized nanoparticles for tumor-targeting co-delivery of doxorubicin and siRNA to enhance cancer therapy

Directory of Open Access Journals (Sweden)

Xia Y

2017-12-01

Full Text Available Yu Xia, Tiantian Xu, Changbing Wang, Yinghua Li, Zhengfang Lin, Mingqi Zhao, Bing Zhu Central Laboratory, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, People’s Republic of China Abstract: Human homeobox protein (Nanog is highly expressed in most cancer cells and has gradually emerged as an excellent target in cancer therapy, owing to its regulation of cancer cell proliferation, metastasis and apoptosis. In this study, we prepared tumor-targeting functionalized selenium nanoparticles (RGDfC-SeNPs to load chemotherapeutic doxorubicin (DOX and Nanog siRNA. Herein, RGDfC peptide was used as a tumor-targeting moiety which could specifically bind to αvβ3 integrins overexpressed on various cancer cells. The sizes of RGDfC-SeNPs@DOX nanoparticles (~12 nm were confirmed by both dynamic light scattering and transmission electron microscopy. The chemical structure of RGDfC-SeNPs@DOX was characterized via Fourier-transform infrared spectroscopy. The RGDfC-SeNPs@DOX was compacted with siRNA (anti-Nanog by electrostatic interaction to fabricate the RGDfC-SeNPs@DOX/siRNA complex. The RGDfC-SeNPs@DOX/siRNA complex nanoparticles could efficiently enter into HepG2 cells via clathrin-associated endocytosis, and showed high gene transfection efficiency that resulted in enhanced gene silencing. The in vivo biodistribution experiment indicated that RGDfC-SeNPs@DOX/siRNA nanoparticles were capable of specifically accumulating in the tumor site. Furthermore, treatment with RGDfC-SeNPs@DOX/siRNA resulted in a more significant anticancer activity than the free DOX, RGDfC-SeNPs@DOX or RGDfC-SeNPs/siRNA in vitro and in vivo. In summary, this study shows a novel type of DOX and siRNA co-delivery system, thereby providing an alternative route for cancer treatment. Keywords: nanoparticles, tumor targeting, drug delivery, doxorubicin, Nanog siRNA

Surface-enhanced Raman effect in hybrid metal–semiconductor nanoparticle assemblies

International Nuclear Information System (INIS)

Lughi, Vanni; Bonifacio, Alois; Barbone, Matteo; Marsich, Lucia; Sergo, Valter

2013-01-01

Hybrid metal–semiconductor nanoparticles consisting of silver nanoparticle cores (AgNPs) coated with a layer of CdSe quantum dots (QDs) have been studied by Raman spectroscopy. The hybrid nanoparticles were prepared via electrostatic interaction by mixing aqueous suspensions of QDs and AgNPs, where opposite charges on the AgNPs and QDs surfaces were induced by opportunely selected capping agents. Assemblies of such hybrid nanoparticles show an increased intensity of the Raman spectrum of up to 500 times, when compared to that of the sole QDs. This enhancement is attributed to the SERS effect (Surface-enhanced Raman scattering). Such enhancement of the Raman modes suggests several opportunities for further research, both in imaging and sensing applications.

CNET and APT : a comparison of two methods for measuring mental representations underlying activity-travel choices

NARCIS (Netherlands)

Horeni, O.; Arentze, T.A.; Dellaert, B.G.C.; Timmermans, H.J.P.

2010-01-01

This paper presents and compares the potential of online versions of two interview techniques (APT and CNET) which have been developed for measuring mental representations underlying activity-travel choices. The comparison is based on the results of a first online survey administered in the

Cell penetrating peptide-modified poly(lactic-co-glycolic acid) nanoparticles with enhanced cell internalization.

Science.gov (United States)

Steinbach, Jill M; Seo, Young-Eun; Saltzman, W Mark

2016-01-01

The surface modification of nanoparticles (NPs) can enhance the intracellular delivery of drugs, proteins, and genetic agents. Here we studied the effect of different surface ligands, including cell penetrating peptides (CPPs), on the cell binding and internalization of poly(lactic-co-glycolic) (PLGA) NPs. Relative to unmodified NPs, we observed that surface-modified NPs greatly enhanced cell internalization. Using one CPP, MPG (unabbreviated notation), that achieved the highest degree of internalization at both low and high surface modification densities, we evaluated the effect of two different NP surface chemistries on cell internalization. After 2h, avidin-MPG NPs enhanced cellular internalization by 5 to 26-fold relative to DSPE-MPG NP formulations. Yet, despite a 5-fold increase in MPG density on DSPE compared to Avidin NPs, both formulations resulted in similar internalization levels (48 and 64-fold, respectively) after 24h. Regardless of surface modification, all NPs were internalized through an energy-dependent, clathrin-mediated process, and became dispersed throughout the cell. Overall both Avidin- and DSPE-CPP modified NPs significantly increased internalization and offer promising delivery options for applications in which internalization presents challenges to efficacious delivery. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Curcumin loaded poly(2-hydroxyethyl methacrylate) nanoparticles from gelled ionic liquid--in vitro cytotoxicity and anti-cancer activity in SKOV-3 cells.

Science.gov (United States)

Kumar, Sathish Sundar Dhilip; Surianarayanan, Mahadevan; Vijayaraghavan, R; Mandal, Asit Baran; MacFarlane, D R

2014-01-23

The main focus of this study is to encapsulate hydrophobic drug curcumin in hydrophilic polymeric core such as poly(2-hydroxyethyl methacrylate) [PHEMA] nanoparticles from gelled ionic liquid (IL) to improve its efficacy. We have achieved 26.4% drug loading in a biocompatible hydrophilic polymer. Curcumin loaded PHEMA nanoparticles (C-PHEMA-NPs) were prepared by nano-precipitation method. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) analysis showed that the prepared nanoparticles were spherical in shape and free from aggregation. The size and zeta potential of prepared C-PHEMA-NPs were about 300 nm and -33.4 mV respectively. C-PHEMA-NPs were further characterized by FT-IR spectroscopy which confirmed the existence of curcumin in the nanoparticles. X-ray diffraction and differential scanning calorimetry studies revealed that curcumin present in the PHEMA nanoparticles were found to be amorphous in nature. The anticancer activity of C-PHEMA-NPs was measured in ovarian cancer cells (SKOV-3) in vitro, and the results revealed that the C-PHEMA-NPs had better tumor cells regression activity than free curcumin. Flow cytometry showed the significant reduction in G0/G1 cells after treatment with C-PHEMA-NPs and molecular level of apoptosis were also studied using western blotting. Toxicity of PHEMA nanoparticles were studied in zebrafish embryo model and results revealed the material to be highly biocompatible. The present study demonstrates the curcumin loaded PHEMA nanoparticles have potential therapeutic values in the treatment of cancer. Copyright © 2013 Elsevier B.V. All rights reserved.

Photothermal enhancement of chemotherapy mediated by gold-silica nanoshell-loaded macrophages: in vitro squamous cell carcinoma study

Science.gov (United States)

Madsen, Steen J.; Shih, En-Chung; Peng, Qian; Christie, Catherine; Krasieva, Tatiana; Hirschberg, Henry

2016-01-01

Moderate hyperthermia (MHT) has been shown to enhance the effects of chemotherapeutic agents in a wide variety of cancers. The purpose of this study was to investigate the combined effects of commonly used chemotherapeutic agents with MHT induced by near-infrared (NIR) activation of gold nanoshell (AuNS)-loaded macrophages (Ma). AuNS-loaded murine Ma combined with human FaDu squamous cells, in hybrid monolayers, were subjected to three cytotoxic drugs (doxorubicin, bleomycin, cisplatin) with or without NIR laser irradiation. For all three drugs, efficacy was increased by NIR activation of AuNS-loaded Ma. The results of this in vitro study provide proof-of-concept for the use of AuNS-loaded Ma for photothermal enhancement of the effects of chemotherapy on squamous cell carcinoma.

Preparation and in vitro characterization of 9-nitrocamptothecin-loaded long circulating nanoparticles for delivery in cancer patients.

Science.gov (United States)

Derakhshandeh, Katayoun; Soheili, Marzieh; Dadashzadeh, Simin; Saghiri, Reza

2010-08-09

The purpose in this study was to investigate poly(ethylene glycol)-modified poly (d,l-lactide-co-glycolide) nanoparticles (PLGA-PEG-NPs) loading 9-nitrocamptothecin (9-NC) as a potent anticancer drug. 9-NC is an analog of the natural plant alkaloid camptothecin that has shown high antitumor activity and is currently in the end stage of clinical trial. Unfortunately, at physiological pH, these potent agents undergo a rapid and reversible hydrolysis with the loss of antitumor activity. Previous researchers have shown that the encapsulation of this drug in PLGA nanoparticles could increase its stability and release profile. In this research we investigated PLGA-PEG nanoparticles and their effect on in vitro characteristics of this labile drug. 9-NC-PLGA-PEG nanoparticles with particle size within the range of 148.5 ± 30 nm were prepared by a nanoprecipitation method. The influence of four different independent variables (amount of polymer, percent of emulsifier, internal phase volume, and external phase volume) on nanoparticle drug-loading was studied. Differential scanning calorimetry and X-ray diffractometry were also evaluated for physical characterizing. The results of optimized formulation showed a narrow size distribution, suitable zeta potential (+1.84), and a drug loading of more than 45%. The in vitro drug release from PLGA-PEG NPs showed a sustained release pattern of up to 120 hours and comparing with PLGA-NPs had a significant decrease in initial burst effect. These experimental results indicate that PLGA-PEG-NPs (versus PLGA-NPs) have a better physicochemical characterization and can be developed as a drug carrier in order to treat different malignancies.

Enhancement of oral bioavailability of cyclosporine A: comparison of various nanoscale drug-delivery systems

Directory of Open Access Journals (Sweden)

Wang K

2014-10-01

Full Text Available Kai Wang,1–3 Jianping Qi,1 Tengfei Weng,1,2 Zhiqiang Tian,1 Yi Lu,1 Kaili Hu,4 Zongning Yin,2 Wei Wu1 1School of Pharmacy, Fudan University, Key Laboratory of Smart Drug Delivery of Ministry of Education, Shanghai, People’s Republic of China; 2West China School of Pharmacy, Sichuan University, Chengdu, Sichuan, People’s Republic of China; 3Tropical Crops Genetic Resources Institute, Hainan Provincial Engineering Research Center for Blumea Balsamifera, Chinese Academy of Tropical Agricultural Sciences, Danzhou, Hainan, People’s Republic of China; 4Murad Research Center for Modernized Chinese Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, People’s Republic of ChinaAbstract: A variety of nanoscale delivery systems have been shown to enhance the oral absorption of poorly water-soluble and poorly permeable drugs. However, the performance of these systems has seldom been evaluated simultaneously. The aim of this study was to compare the bioavailability enhancement effect of lipid-based nanocarriers with poly(lactic-co-glycolic acid (PLGA nanoparticles (NPs to highlight the importance of the lipid composition, with cyclosporine A (CyA as a model drug. CyA-loaded PLGA NPs, nanostructured lipid carriers (NLCs, and self-microemulsifying drug-delivery systems (SMEDDS were prepared. The particle size of PLGA NPs (182.2±12.8 nm was larger than that of NLCs (89.7±9.0 nm and SMEDDS (26.9±1.9 nm. All vehicles are charged negatively. The entrapment efficiency of PLGA NPs and NLCs was 87.6%±1.6% and 80.3%±0.6%, respectively. In vitro release tests indicated that the cumulative release of CyA was lower than 4% from all vehicles, including Sandimmun Neoral®, according to the dialysis method. Both NLCs and SMEDDS showed high relative oral bioavailability, 111.8% and 73.6%, respectively, after oral gavage administration to beagle dogs, which was not statistically different from commercial Sandimmun Neoral®. However, PLGA NPs

Folate attached, curcumin loaded Fe{sub 3}O{sub 4} nanoparticles: A novel multifunctional drug delivery system for cancer treatment

Energy Technology Data Exchange (ETDEWEB)

Thu Huong, Le Thi [Institute of Materials Science, Ha Noi 844 (Viet Nam); Vietnam National University of Agriculture, Ha Noi 844 (Viet Nam); Nam, Nguyen Hoai, E-mail: nhnam@ims.vast.ac.vn [Institute of Materials Science, Ha Noi 844 (Viet Nam); Doan, Do Hai [Institute of Materials Science, Ha Noi 844 (Viet Nam); My Nhung, Hoang Thi [Hanoi University of Science, Vietnam National University, Ha Noi 844 (Viet Nam); Quang, Bui Thuc [National Gegiatrics Hospital, Ha Noi 844 (Viet Nam); Nam, Pham Hong; Thong, Phan Quoc; Phuc, Nguyen Xuan [Institute of Materials Science, Ha Noi 844 (Viet Nam); Thu, Ha Phuong, E-mail: thuhp@ims.vast.ac.vn [Institute of Materials Science, Ha Noi 844 (Viet Nam)

2016-04-01

Study and development of drug delivery nanosystem for cancer treatment are attracting great attention in recent years. In this work, we studied the role of folic acid as a targeting factor on magnetic nanoparticle Fe{sub 3}O{sub 4} based curcumin loading nanosystem. Characteristics of the nanosystems were investigated by Fourier transform infrared spectroscopy (FTIR) and field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), thermal gravimetric analysis (TGA) and vibrating sample magnetometer (VSM), while targeting role of folic was accessed in vivo on tumor bearing mice. The results showed that folate attached Fe{sub 3}O{sub 4} based curcumin loading nanosystem has very small size and exhibits better targeting effect compared to the counterpart without folate. In addition, magnetic induction heating of this nanosystem evidenced its potential for cancer hyperthermia. - Highlights: • Folate attached, curcumin loaded Fe3O4 nanoparticles were prepared and characterized. • The NPs have high curcumin loading capacity and good ability for hyperthermia. • Folate shows its bioactivity of effectively targeting the NPs to tumor tissues. • Chemotherapy, hyperthermia and targeting factor are all well combined in the NPs.

Navy-wide Personnel Survey (NPS) 2005: Tabulated Results

National Research Council Canada - National Science Library

Whittam, Kimberly P

2007-01-01

.... The NPS focused on work-life topics, such as job satisfaction, leadership satisfaction, morale, career intentions, career development, advancement and promotion, detailing, TEMPO, gender integration...

Adsorption of Pb(II) using silica gel composite from rice husk ash modified 3-aminopropyltriethoxysilane (APTES)-activated carbon from coconut shell

Science.gov (United States)

Yusmaniar, Purwanto, Agung; Putri, Elfriyana Awalita; Rosyidah, Dzakiyyatur

2017-03-01

Silica gel modified by 3-aminopropyltriethoxysilane (APTES) was synthesized from rice husk ash combined with activated carbon from coconut shell yielded the composite adsorbent. The composite was characterized by Fourier Transform Infra Red spectroscopy (FT-IR), Electron Dispersive X-Ray (EDX), Surface Area Analyzer (SAA) and adsorption test by Atomic Absorption Spectrometry (AAS). This composite adsorbent has been used moderately for the removal of lead ions from metal solutions and compared with silica gel modified APTES and activated carbon. The adsorption experiments of Pb -ions by adsorbents were performed at different pH and contact time with the same metal solutions concentration, volume solution, and adsorbent dosage. The optimum pH for the adsorption was found to be 5.0 and the equilibrium was achieved for Pb with 20 min of contact time. Pb ions adsorption by composite silica gel modified APTES-activated carbon followed by Langmuir isotherm model with qmax value of 46.9483 mg/g that proved an adsorbent mechanism consistent to the mechanism of monolayer formation.

A biodynamic understanding of dietborne and waterborne Ag uptake from Ag NPs in the sediment-dwelling oligochaete, Tubifex tubifex

Science.gov (United States)

Tangaa, Stine Rosendal; Winther-Nielsen, Margrethe; Selck, Henriette; Croteau, Marie-Noele

2018-01-01

Metal nanoparticles (Me-NPs) are increasingly used in various products, such as inks and cosmetics, enhancing the likelihood of their release into aquatic environments. An understanding of the mechanisms controlling their bioaccumulation and ecotoxicity in aquatic biota will help support environmental risk assessment. Here we characterized unidirectional parameters for uptake and elimination of silver (Ag) in the sediment-dwelling oligochaete Tubifex tubifex after waterborne (0.01–47 nmol Ag/L) and dietborne (0.4–482 nmol Ag/g dw sed.) exposures to Ag NPs and AgNO3, respectively. Worms accumulated Ag from AgNO3more efficiently than from Ag NPs during waterborne exposure. The Ag uptake rate constants from water were 8.2 L/g/d for AgNO3 and 0.34 L/g/d for Ag NPs. Silver accumulated from both forms was efficiently retained in tissues, as no significant loss of Ag was detected after up to 20 days of depuration in clean media. High mortality (~50%) during depuration (i.e. after 17 days) was only observed for worms exposed to waterborne AgNO3 (3 nmol/L). Sediment exposures to both Ag forms resulted in low accumulation, i.e., the uptake rate constants were 0.002 and 0.005 g/g/d for AgNO3 and Ag NPs, respectively. Avoidance was only observed for worms exposed to sediment amended with AgNO3. Incorporation of the estimated rate constants into a biodynamic model predicted that sediment is likely the most important route of uptake for Ag in both forms in ecologically relevant aquatic environments. However, inference of bioavailability from our estimations of Ag assimilation efficiencies (AE) suggests that Ag (AE: 3–12% for AgNO3 and 0.1–0.8% for Ag NPs) is weakly bioavailable from sediment for this species. Thus, Ag amended to sediment as NPs might not pose greater problems than 'conventional' Ag for benthic organisms such as T. tubifex.

Cyclodextrin-Modified Porous Silicon Nanoparticles for Efficient Sustained Drug Delivery and Proliferation Inhibition of Breast Cancer Cells.

Science.gov (United States)

Correia, Alexandra; Shahbazi, Mohammad-Ali; Mäkilä, Ermei; Almeida, Sérgio; Salonen, Jarno; Hirvonen, Jouni; Santos, Hélder A

2015-10-21

Over the past decade, the potential of polymeric structures has been investigated to overcome many limitations related to nanosized drug carriers by modulating their toxicity, cellular interactions, stability, and drug-release kinetics. In this study, we have developed a successful nanocomposite consisting of undecylenic acid modified thermally hydrocarbonized porous silicon nanoparticles (UnTHCPSi NPs) loaded with an anticancer drug, sorafenib, and surface-conjugated with heptakis(6-amino-6-deoxy)-β-cyclodextrin (HABCD) to show the impact of the surface polymeric functionalization on the physical and biological properties of the drug-loaded nanoparticles. Cytocompatibility studies showed that the UnTHCPSi-HABCD NPs were not toxic to breast cancer cells. HABCD also enhanced the suspensibility and both the colloidal and plasma stabilities of the UnTHCPSi NPs. UnTHCPSi-HABCD NPs showed a significantly increased interaction with breast cancer cells compared to bare NPs and also sustained the drug release. Furthermore, the sorafenib-loaded UnTHCPSi-HABCD NPs efficiently inhibited cell proliferation of the breast cancer cells.

Metal Nanoparticles/Porous Silicon Microcavity Enhanced Surface Plasmon Resonance Fluorescence for the Detection of DNA

Directory of Open Access Journals (Sweden)

Jiajia Wang

2018-02-01

Full Text Available A porous silicon microcavity (PSiMC with resonant peak wavelength of 635 nm was fabricated by electrochemical etching. Metal nanoparticles (NPs/PSiMC enhanced fluorescence substrates were prepared by the electrostatic adherence of Au NPs that were distributed in PSiMC. The Au NPs/PSiMC device was used to characterize the target DNA immobilization and hybridization with its complementary DNA sequences marked with Rhodamine red (RRA. Fluorescence enhancement was observed on the Au NPs/PSiMC device substrate; and the minimum detection concentration of DNA ran up to 10 pM. The surface plasmon resonance (SPR of the MC substrate; which is so well-positioned to improve fluorescence enhancement rather the fluorescence enhancement of the high reflection band of the Bragg reflector; would welcome such a highly sensitive in biosensor.

Metal Nanoparticles/Porous Silicon Microcavity Enhanced Surface Plasmon Resonance Fluorescence for the Detection of DNA.

Science.gov (United States)

Wang, Jiajia; Jia, Zhenhong

2018-02-23

A porous silicon microcavity (PSiMC) with resonant peak wavelength of 635 nm was fabricated by electrochemical etching. Metal nanoparticles (NPs)/PSiMC enhanced fluorescence substrates were prepared by the electrostatic adherence of Au NPs that were distributed in PSiMC. The Au NPs/PSiMC device was used to characterize the target DNA immobilization and hybridization with its complementary DNA sequences marked with Rhodamine red (RRA). Fluorescence enhancement was observed on the Au NPs/PSiMC device substrate; and the minimum detection concentration of DNA ran up to 10 pM. The surface plasmon resonance (SPR) of the MC substrate; which is so well-positioned to improve fluorescence enhancement rather the fluorescence enhancement of the high reflection band of the Bragg reflector; would welcome such a highly sensitive in biosensor.

Penetration of polymeric nanoparticles loaded with an HIV-1 inhibitor peptide derived from GB virus C in a vaginal mucosa model.

Science.gov (United States)

Ariza-Sáenz, Martha; Espina, Marta; Bolaños, Nuria; Calpena, Ana Cristina; Gomara, María José; Haro, Isabel; García, María Luisa

2017-11-01

Despite the great effort to decrease the HIV infectivity rate, current antiretroviral therapy has several weaknesses; poor bioavailability, development of drug resistance and poor ability to access tissues. However, molecules such as peptides have emerged asa new expectative to HIV eradication. The vaginal mucosa is the main spreading point of HIV. There are natural barriers such as the vaginal fluid which protects the vaginal epithelium from any foreign agents reaching it. This work has developed and characterized Nanoparticles (NPs) coated with glycol chitosan (GC), loaded with an HIV-1 inhibitor peptide (E2). In vitro release and ex vivo studies were carried out using the vaginal mucosa of swine and the peptide was determined by HPLC MS/MS validated method. Moreover, the peptide was labeled with 5(6)-carboxyfluoresceine and entrapped into the NPs to carried out in vivo studies and to evaluate the NPs penetration and toxicity in the vaginal mucosa of the swine. The mean size of the NPs, ξ and the loading percentage were fundamental features for to reach the vaginal tissue and to release the peptide within intercellular space. The obtained results suggesting that the fusion inhibitor peptides loaded into the NPs coated with GC might be a new way to fight the HIV-1, due to the formulation might reach the human epithelial mucosa and release peptide without any side effects. Copyright © 2017 Elsevier B.V. All rights reserved.

Enhancement of radiation cytotoxicity by gold nanoparticles in MCF-7 breast cancer cell lines

Energy Technology Data Exchange (ETDEWEB)

Rosli, Nur Shafawati binti; Rahman, Azhar Abdul [School of Physics, Universiti Sains Malaysia, 11800, Pulau Pinang (Malaysia); Aziz, Azlan Abdul [School of Physics, Universiti Sains Malaysia, 11800, Pulau Pinang (Malaysia); Nano-Biotechnology Research and Innovation (NanoBRI), Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, 11800, Pulau Pinang (Malaysia); Shamsuddin, Shaharum [Nano-Biotechnology Research and Innovation (NanoBRI), Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, 11800, Pulau Pinang (Malaysia); School of Health Sciences, Health Campus, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan (Malaysia)

2015-04-24

Therapy combined with metallic nanoparticles is a new way to treat cancer, in which gold nanoparticles (AuNPs) are injected through intravenous administration and bound to tumor sites. Radiotherapy aims to deliver a high therapeutic dose of ionizing radiation to the tumor without exceeding normal tissue tolerance. The use of AuNPs which is a high-atomic-number (Z) material in radiotherapy will provide a high probability for photon interaction by photoelectric effect. These provide advantages in terms of radiation dose enhancement. The high linear energy transfer and short range of photoelectric interaction products (photoelectrons, characteristic x-rays, Auger electrons) produce localized dose enhancement of the tumor. In this work, breast cancer cell lines (MCF-7) are seeded in the 96-well plate and were treated with 13 nm AuNPs before they were irradiated with 6 MV and 10 MV photon beam from a medical linear accelerator at various radiation doses. To validate the enhanced killing effect, both with and without AuNPs MCF-7 cells is irradiated simultaneously. By comparison, the results show that AuNPs significantly enhance cancer killing.

Study of fungicidal properties of colloidal silver nanoparticles (AgNPs on trout egg pathogen, Saprolegnia sp.

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Seyed Ali Johari

2015-05-01

Full Text Available Silver nanoparticles (AgNPs are known to have bactericidal and fungicidal effects. Since, there is few information available on the interaction of colloidal nanosilver with fish pathogens. Hence, the current study investigated the effects of colloidal AgNPs on the in vitro growth of the fish pathogen Saprolegnia sp.. Before the experiments, various important properties of AgNPs were well-characterized. The antifungal activity of AgNPs was then evaluated by determining the minimum inhibitory concentrations (MICs using two-fold serial dilutions of colloidal nanosilver in a glucose yeast extract agar at 22ºC. The growth of Saprolegnia sp. on the AgNPs agar treatments was compared to that of nanosilver-free agar as controls. The results showed that AgNPs have an inhibitory effect on the in vitro growth of the tested fungi. The MIC of AgNPs for Saprolegnia sp. was calculated at 1800 mg/L, which is equal to 0.18 percent. It seems that AgNPs could be a proper replacement for teratogenic and toxic agents, such as malachite green. In addition, the indirect use of AgNPs could be a useful method for providing new antifungal activity in aquaculture systems.

Neuronal Uptake and Neuroprotective Properties of Curcumin-Loaded Nanoparticles on SK-N-SH Cell Line: Role of Poly(lactide-co-glycolide) Polymeric Matrix Composition.

Science.gov (United States)

Djiokeng Paka, Ghislain; Doggui, Sihem; Zaghmi, Ahlem; Safar, Ramia; Dao, Lé; Reisch, Andreas; Klymchenko, Andrey; Roullin, V Gaëlle; Joubert, Olivier; Ramassamy, Charles

2016-02-01

Curcumin, a neuroprotective agent with promising therapeutic approach has poor brain bioavailability. Herein, we demonstrate that curcumin-encapsulated poly(lactide-co-glycolide) (PLGA) 50:50 nanoparticles (NPs-Cur 50:50) are able to prevent the phosphorylation of Akt and Tau proteins in SK-N-SH cells induced by H2O2 and display higher anti-inflammatory and antioxidant activities than free curcumin. PLGA can display various physicochemical and degradation characteristics for controlled drug release applications according to the matrix used. We demonstrate that the release of curcumin entrapped into a PLGA 50:50 matrix (NPs-Cur 50:50) is faster than into PLGA 65:35. We have studied the effects of the PLGA matrix on the expression of some key antioxidant- and neuroprotective-related genes such as APOE, APOJ, TRX, GLRX, and REST. NPs-Cur induced the elevation of GLRX and TRX while decreasing APOJ mRNA levels and had no effect on APOE and REST expressions. In the presence of H2O2, both NPs-Cur matrices are more efficient than free curcumin to prevent the induction of these genes. Higher uptake was found with NPs-Cur 50:50 than NPs-Cur 65:35 or free curcumin. By using PLGA nanoparticles loaded with the fluorescent dye Lumogen Red, we demonstrated that PLGA nanoparticles are indeed taken up by neuronal cells. These data highlight the importance of polymer composition in the therapeutic properties of the nanodrug delivery systems. Our study demonstrated that NPs-Cur enhance the action of curcumin on several pathways implicated in the pathophysiology of Alzheimer's disease (AD). Overall, these results suggest that PLGA nanoparticles are a promising strategy for the brain delivery of drugs for the treatment of AD.

Fullerene–epoxy nanocomposites-enhanced mechanical properties at low nanofiller loading

International Nuclear Information System (INIS)

Rafiee, Mohammad A.; Yavari, Fazel; Rafiee, Javad; Koratkar, Nikhil

2011-01-01

In this study, we characterized the mechanical properties of fullerence (C 60 ) epoxy nanocomposites at various weight fractions of fullerene additives in the epoxy matrix. The mechanical properties measured were the Young’s modulus, ultimate tensile strength, fracture toughness, fracture energy, and the material’s resistance to fatigue crack propagation. All of the above properties of the epoxy polymer were significantly enhanced by the fullerene additives at relatively low nanofiller loading fractions (∼0.1 to 1% of the epoxy matrix weight). By contrast, other forms of nanoparticle fillers such as silica, alumina, and titania nanoparticles require up to an order of magnitude higher weight fraction to achieve comparable enhancement in properties.

Human Albumin Fragments Nanoparticles as PTX Carrier for Improved Anti-cancer Efficacy

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Liang Ge

2018-06-01

Full Text Available For enhanced anti-cancer performance, human serum albumin fragments (HSAFs nanoparticles (NPs were developed as paclitaxel (PTX carrier in this paper. Human albumins were broken into fragments via degradation and crosslinked by genipin to form HSAF NPs for better biocompatibility, improved PTX drug loading and sustained drug release. Compared with crosslinked human serum albumin NPs, the HSAF-NPs showed relative smaller particle size, higher drug loading, and improved sustained release. Cellular and animal results both indicated that the PTX encapsulated HSAF-NPs have shown good anti-cancer performance. And the anticancer results confirmed that NPs with fast cellular internalization showed better tumor inhibition. These findings will not only provide a safe and robust drug delivery NP platform for cancer therapy, but also offer fundamental information for the optimal design of albumin based NPs.

Evaluation of genotoxic effect of silver nanoparticles (Ag-Nps) in vitro and in vivo

International Nuclear Information System (INIS)

Tavares, Priscila; Balbinot, Fernanda; Martins de Oliveira, Hugo; Elibio Fagundes, Gabriela; Venâncio, Mireli; Vieira Ronconi, João Vitor; Merlini, Aline; Streck, Emílio L.; Marques da Silva, Paula; Moraes de Andrade, Vanessa

2012-01-01

Silver nanoparticles (Ag-NPs) are the most prominent nanoproducts. Due to their antimicrobial activity, they have been incorporated in different materials, such as catheters, clothes, electric home appliance, and many others. The genotoxicity of Ag-NPs (5–45 nm), in different concentrations and times of exposure, was evaluated by the comet assay in in vitro and in vivo conditions, respectively, using human peripheral blood and Swiss mice. The results showed the genotoxic effect of Ag-NPs in vitro, in all the doses tested in the initial hour of exposure, possibly through the reactive oxygen species generation. Nevertheless, the values for this damage decrease with time, indicating that the DNA may have been restored by the repair system. In the in vivo conditions, we found no genotoxicity of Ag-NPs in any hour of exposure and any dose investigated, which can be attributed to the activation of a cellular antioxidant network and the hydrophobic nature of Ag-NPs. Now, it is absolutely necessary to investigate the role of Ag-NPs in different cell lines in vivo.

Evaluation of genotoxic effect of silver nanoparticles (Ag-Nps) in vitro and in vivo

Energy Technology Data Exchange (ETDEWEB)

Tavares, Priscila; Balbinot, Fernanda; Martins de Oliveira, Hugo; Elibio Fagundes, Gabriela [PPGCS, Universidade do Extremo Sul Catarinense, Laboratorio de Biologia Celular e Molecular (Brazil); Venancio, Mireli; Vieira Ronconi, Joao Vitor; Merlini, Aline [Universidade do Extremo Sul Catarinense, Laboratorio de Sintese de Complexos Multifuncionais (Brazil); Streck, Emilio L. [Programa de Pos-Graduacao em Ciencias da Saude, Unidade Academica de Ciencias da Saude, Universidade do Extremo Sul Catarinense, Laboratorio de Fisiopatologia Experimental (Brazil); Marques da Silva, Paula [Universidade do Extremo Sul Catarinense, Laboratorio de Sintese de Complexos Multifuncionais (Brazil); Moraes de Andrade, Vanessa, E-mail: vmoraesdeandrade@yahoo.com.br [PPGCS, Universidade do Extremo Sul Catarinense, Laboratorio de Biologia Celular e Molecular (Brazil)

2012-03-15

Silver nanoparticles (Ag-NPs) are the most prominent nanoproducts. Due to their antimicrobial activity, they have been incorporated in different materials, such as catheters, clothes, electric home appliance, and many others. The genotoxicity of Ag-NPs (5-45 nm), in different concentrations and times of exposure, was evaluated by the comet assay in in vitro and in vivo conditions, respectively, using human peripheral blood and Swiss mice. The results showed the genotoxic effect of Ag-NPs in vitro, in all the doses tested in the initial hour of exposure, possibly through the reactive oxygen species generation. Nevertheless, the values for this damage decrease with time, indicating that the DNA may have been restored by the repair system. In the in vivo conditions, we found no genotoxicity of Ag-NPs in any hour of exposure and any dose investigated, which can be attributed to the activation of a cellular antioxidant network and the hydrophobic nature of Ag-NPs. Now, it is absolutely necessary to investigate the role of Ag-NPs in different cell lines in vivo.

RGD-modified poly(D,L-lactic acid nanoparticles enhance tumor targeting of oridonin

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Xu J

2012-01-01

Full Text Available Jie Xu, Ji-Hui Zhao, Ying Liu, Nian-Ping Feng, Yong-Tai ZhangSchool of Pharmacy, Shanghai University of Traditional Chinese Medicine, Shanghai, People's Republic of ChinaObjective: The purpose of this study was to develop an active targeting strategy to improve the therapeutic antitumor efficacy of oridonin (ORI, the main active ingredient in the medicinal herb Rabdosia rubescens.Methods: A modified spontaneous emulsification solvent diffusion method was used to prepare the ORI-loaded atactic poly(D,L-lactic acid nanoparticles (ORI-PLA-NPs. Surface cross-linking with the peptide Arg-Gly-Asp (RGD further modified the ORI-PLA-NPs, generating ORI-PLA-RGD-NPs. The NPs were characterized and release experiments were performed in vitro. The pharmacokinetics, tissue distribution, and antitumor activity of the NPs were studied in mice bearing hepatocarcinoma 22 (H22-derived tumors.Results: The ORI-PLA-NPs and ORI-PLA-RGD-NPs were smooth, sphere-like, and relatively uniform in size. The RGD surface modification slightly increased the mean particle size (95.8 nm for ORI-PLA-NPs versus 105.2 nm for ORI-PLA-RGD-NPs and considerably altered the surface electrical property (-10.19 mV for ORI-PLA-NPs versus -21.95 mV for ORI-PLA-RGD-NPs, but it had no obvious influence on ORI loading (8.23% ± 0.35% for ORI-PLA-NPs versus 8.02% ± 0.38% for ORI-PLA-RGD-NPs, entrapment efficiency (28.86% ± 0.93% for ORI-PLA-NPs versus 28.24% ± 0.81% for ORI-PLA-RGD-NPs, or the release of ORI. The pharmacokinetic properties of free ORI were improved by encapsulation in NPs, as shown by increased area under the concentration-time curve (11.89 ± 0.35 µg·mL-1 · h for ORI solution versus 22.03 ± 0.01 µg · mL-1 · h for ORI-PLA-RGD-NPs and prolonged mean retention time (2.03 ± 0.09 hours for ORI solution versus 8.68 ± 0.66 hours for ORI-PLA-RGD-NPs. In the tissue distribution study, more ORI targeted tumor tissue in the mice treated with ORI-PLA-RGD-NPs than with ORI-PLA-NPs

Radiation protection system installation for the accelerator production of tritium/low energy demonstration accelerator project (APT/LEDA)

CERN Document Server

Wilmarth, J E; Tomei, T L

2000-01-01

The APT/LEDA personnel radiation protection system installation was accomplished using a flexible, modular proven system which satisfied regulatory orders, project design criteria, operational modes, and facility requirements. The goal of providing exclusion and safe access of personnel to areas where prompt radiation in the LEDA facility is produced was achieved with the installation of a DOE-approved Personnel Access Control System (PACS). To satisfy the facility configuration design, the PACS, a major component of the overall radiation safety system, conveniently provided five independent areas of personnel access control. Because of its flexibility and adaptability the Los-Alamos Neutron- Science-Center-(LANSCE)-designed Radiation Security System (RSS) was efficiently configured to provide the desired operational modes and satisfy the APT/LEDA project design criteria. The Backbone Beam Enable (BBE) system based on the LANSCE RSS provided the accelerator beam control functions with redundant, hardwired, ta...

Synthesis, characterization and in vitro study of biocompatible cinnamaldehyde functionalized magnetite nanoparticles (CPGF Nps for hyperthermia and drug delivery applications in breast cancer.

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Kirtee D Wani

Full Text Available Cinnamaldehyde, the bioactive component of the spice cinnamon, and its derivatives have been shown to possess anti-cancer activity against various cancer cell lines. However, its hydrophobic nature invites attention for efficient drug delivery systems that would enhance the bioavailability of cinnamaldehyde without affecting its bioactivity. Here, we report the synthesis of stable aqueous suspension of cinnamaldehyde tagged Fe3O4 nanoparticles capped with glycine and pluronic polymer (CPGF NPs for their potential application in drug delivery and hyperthermia in breast cancer. The monodispersed superparamagnetic NPs had an average particulate size of ∼ 20 nm. TGA data revealed the drug payload of ∼ 18%. Compared to the free cinnamaldehyde, CPGF NPs reduced the viability of breast cancer cell lines, MCF7 and MDAMB231, at lower doses of cinnamaldehyde suggesting its increased bioavailability and in turn its therapeutic efficacy in the cells. Interestingly, the NPs were non-toxic to the non-cancerous HEK293 and MCF10A cell lines compared to the free cinnamaldehyde. The novelty of CPGF nanoparticulate system was that it could induce cytotoxicity in both ER/PR positive/Her2 negative (MCF7 and ER/PR negative/Her2 negative (MDAMB231 breast cancer cells, the latter being insensitive to most of the chemotherapeutic drugs. The NPs decreased the growth of the breast cancer cells in a dose-dependent manner and altered their migration through reduction in MMP-2 expression. CPGF NPs also decreased the expression of VEGF, an important oncomarker of tumor angiogenesis. They induced apoptosis in breast cancer cells through loss of mitochondrial membrane potential and activation of caspase-3. Interestingly, upon exposure to the radiofrequency waves, the NPs heated up to 41.6 °C within 1 min, suggesting their promise as a magnetic hyperthermia agent. All these findings indicate that CPGF NPs prove to be potential nano-chemotherapeutic agents in breast cancer.

Loads and loads and loads: The influence of prospective load, retrospective load, and ongoing task load in prospective memory

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Beat eMeier

2015-06-01

Full Text Available In prospective memory tasks different kinds of load can occur. Adding a prospective memory task can impose a load on ongoing task performance. Adding ongoing task load can affect prospective memory performance. The existence of multiple target events increases prospective load and adding complexity to the to-be-remembered action increases retrospective load. In two experiments, we systematically examined the effects of these different types of load on prospective memory performance. Results showed an effect of prospective load on costs in the ongoing task for categorical targets (Experiment 2, but not for specific targets (Experiment 1. Retrospective load and ongoing task load both affected remembering the retrospective component of the prospective memory task. We suggest that prospective load can enhance costs in the ongoing task due to additional monitoring requirements. Retrospective load and ongoing task load seem to impact the division of resources between the ongoing task and retrieval of the retrospective component, which may affect disengagement from the ongoing task. In general, the results demonstrate that the different types of load affect prospective memory differentially.

Antimicrobial activity of a new synthetic peptide loaded in polylactic acid or poly(lactic-co-glycolic) acid nanoparticles against Pseudomonas aeruginosa, Escherichia coli O157:H7 and methicillin resistant Staphylococcus aureus (MRSA)

Science.gov (United States)

Cruz, J.; Flórez, J.; Torres, R.; Urquiza, M.; Gutiérrez, J. A.; Guzmán, F.; Ortiz, C. C.

2017-03-01

Nanocarrier systems are currently being developed for peptide, protein and gene delivery to protect them in the blood circulation and in the gastrointestinal tract. Polylactic acid (PLA) and poly(lactic-co-glycolic) acid (PLGA) nanoparticles loaded with a new antimicrobial GIBIM-P5S9K peptide were obtained by the double emulsion solvent extraction/evaporation method. PLA- and PLGA-NPs were spherical with sizes between 300 and 400 nm for PLA and 200 and 300 nm for PLGA and 20 mV. The peptide-loading efficiency of PLA-NP and PLGA-NPs was 75% and 55%, respectively. PLA- and PLGA-NPs released around 50% of this peptide over 8 h. In 10% human sera the size of peptide loaded PLA- and PLGA-NPs increased between 25.2% and 39.3%, the PDI changed from 3.2 to 5.1 and the surface charge from -7.15 to 14.6 mV. Both peptide loaded PLA- and PLGA-NPs at 0.5 μM peptide concentration inhibited the growth of Escherichia coli O157:H7 (E. coli O157:H7), methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas. aeruginosa (P. aeruginosa). In contrast, free peptide inhibited at 10 μM but did not inhibit at 0.5 and 1 μM. These PLA- and PLGA-NPs presented <10% hemolysis indicating that they are hemocompatible and promising for delivery and protection system of GIBIM-P5S9K peptide.

Kaempferol loaded lecithin/chitosan nanoparticles: preparation, characterization, and their potential applications as a sustainable antifungal agent.

Science.gov (United States)

Ilk, Sedef; Saglam, Necdet; Özgen, Mustafa

2017-08-01

Flavonoid compounds are strong antioxidant and antifungal agents but their applications are limited due to their poor dissolution and bioavailability. The use of nanotechnology in agriculture has received increasing attention, with the development of new formulations containing active compounds. In this study, kaempferol (KAE) was loaded into lecithin/chitosan nanoparticles (LC NPs) to determine antifungal activity compared to pure KAE against the phytopathogenic fungus Fusarium oxysporium to resolve the bioavailability problem. The influence of formulation parameters on the physicochemical properties of KAE loaded lecithin chitosan nanoparticles (KAE-LC NPs) were studied by using the electrostatic self-assembly technique. KAE-LC NPs were characterized in terms of physicochemical properties. KAE has been successfully encapsulated in LC NPs with an efficiency of 93.8 ± 4.28% and KAE-LC NPs showed good physicochemical stability. Moreover, in vitro evaluation of the KAE-LC NP system was made by the release kinetics, antioxidant and antifungal activity in a time-dependent manner against free KAE. Encapsulated KAE exhibited a significantly inhibition efficacy (67%) against Fusarium oxysporium at the end of the 60 day storage period. The results indicated that KAE-LC NP formulation could solve the problems related to the solubility and loss of KAE during use and storage. The new nanoparticle system enables the use of smaller quantities of fungicide and therefore, offers a more environmentally friendly method of controlling fungal pathogens in agriculture.

Immunotoxicity of Silver Nanoparticles (AgNPs) on the Leukocytes of Common Bottlenose Dolphins (Tursiops truncatus).

Science.gov (United States)

Li, Wen-Ta; Chang, Hui-Wen; Yang, Wei-Cheng; Lo, Chieh; Wang, Lei-Ya; Pang, Victor Fei; Chen, Meng-Hsien; Jeng, Chian-Ren

2018-04-04

Silver nanoparticles (AgNPs) have been extensively used and are considered as an emerging contaminant in the ocean. The environmental contamination of AgNPs is expected to increase greatly over time, and cetaceans, as the top ocean predators, will suffer the negative impacts of AgNPs. In the present study, we investigate the immunotoxicity of AgNPs on the leukocytes of cetaceans using several methods, including cytomorphology, cytotoxicity, and functional activity assays. The results reveal that 20 nm Citrate-AgNPs (C-AgNP 20 ) induce different cytomorphological alterations and intracellular distributions in cetacean polymorphonuclear cells (cPMNs) and peripheral blood mononuclear cells (cPBMCs). At high concentrations of C-AgNP 20 (10 and 50 μg/ml), the time- and dose-dependent cytotoxicity in cPMNs and cPBMCs involving apoptosis is demonstrated. C-AgNP 20 at sub-lethal doses (0.1 and 1 μg/ml) negatively affect the functional activities of cPMNs (phagocytosis and respiratory burst) and cPBMCs (proliferative activity). The current study presents the first evidence of the cytotoxicity and immunotoxicity of AgNPs on the leukocytes of cetaceans and improves our understanding of environmental safety concerning AgNPs. The dose-response data of AgNPs on the leukocytes of cetaceans are invaluable for evaluating the adverse health effects in cetaceans and for proposing a conservation plan for marine mammals.

Application of modified export coefficient method on the load estimation of non-point source nitrogen and phosphorus pollution of soil and water loss in semiarid regions.

Science.gov (United States)

Wu, Lei; Gao, Jian-en; Ma, Xiao-yi; Li, Dan

2015-07-01

Chinese Loess Plateau is considered as one of the most serious soil loss regions in the world, its annual sediment output accounts for 90 % of the total sediment loads of the Yellow River, and most of the Loess Plateau has a very typical characteristic of "soil and water flow together", and water flow in this area performs with a high sand content. Serious soil loss results in nitrogen and phosphorus loss of soil. Special processes of water and soil in the Loess Plateau lead to the loss mechanisms of water, sediment, nitrogen, and phosphorus are different from each other, which are greatly different from other areas of China. In this study, the modified export coefficient method considering the rainfall erosivity factor was proposed to simulate and evaluate non-point source (NPS) nitrogen and phosphorus loss load caused by soil and water loss in the Yanhe River basin of the hilly and gully area, Loess Plateau. The results indicate that (1) compared with the traditional export coefficient method, annual differences of NPS total nitrogen (TN) and total phosphorus (TP) load after considering the rainfall erosivity factor are obvious; it is more in line with the general law of NPS pollution formation in a watershed, and it can reflect the annual variability of NPS pollution more accurately. (2) Under the traditional and modified conditions, annual changes of NPS TN and TP load in four counties (districts) took on the similar trends from 1999 to 2008; the load emission intensity not only is closely related to rainfall intensity but also to the regional distribution of land use and other pollution sources. (3) The output structure, source composition, and contribution rate of NPS pollution load under the modified method are basically the same with the traditional method. The average output structure of TN from land use and rural life is about 66.5 and 17.1 %, the TP is about 53.8 and 32.7 %; the maximum source composition of TN (59 %) is farmland; the maximum source

Development of Yam Dioscorin-Loaded Nanoparticles for Paracellular Transport Across Human Intestinal Caco-2 Cell Monolayers.

Science.gov (United States)

Hsieh, Hung-Ling; Lee, Chia-Hung; Lin, Kuo-Chih

2018-02-07

Dioscorins, the major storage proteins of yam tubers, exert immunomodulatory activities. To improve oral bioavailability of dioscorins in the intestine, recombinant dioscorin (rDioscorin) was coated with N,N,N-trimethyl chitosan (TMC) and tripolyphosphate (TPP), resulting in the formation of TMC-rDio-TPP nanoparticles (NPs). The loading capacity and entrapment efficiency of rDioscorin in the NPs were 26 ± 0.7% and 61 ± 1.4%, respectively. The NPs demonstrated a substantial release profile in the pH environment of the jejunum. The rDioscorin released from the NPs stimulated proliferation and phagocytosis of the macrophage RAW264.7 and activated the gene expression of IL-1β and IL-6. Incubation of the NPs in the Caco-2 cell monolayer led to a 5.2-fold increase of P app compared with rDioscorin alone, suggesting that rDioscorin, with the assistance of TMC, can be promptly transported across the intestinal epithelia. These results demonstrate that the TMC-rDio-TPP NPs can be utilized for elucidating the immunopharmacological effects of dioscorins through oral delivery.

A novel vehicle for local protein delivery to the inner ear: injectable and biodegradable thermosensitive hydrogel loaded with PLGA nanoparticles.

Science.gov (United States)

Dai, Juan; Long, Wei; Liang, Zhongping; Wen, Lu; Yang, Fan; Chen, Gang

2018-01-01

Delivery of biomacromolecular drugs into the inner ear is challenging, mainly because of their inherent instability as well as physiological and anatomical barriers. Therefore, protein-friendly, hydrogel-based delivery systems following local administration are being developed for inner ear therapy. Herein, biodegradable poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) containing interferon α-2 b (IFN α-2 b) were loaded in chitosan/glycerophosphate (CS/GP)-based thermosensitive hydrogel for IFN delivery by intratympanic injection. The injectable hydrogel possessed a physiological pH and formed semi-solid gel at 37 °C, with good swelling and deswelling properties. The CS/GP hydrogel could slowly degrade as visualized by scanning electron microscopy (SEM). The presence of NPs in CS/GP gel largely influenced in vitro drug release. In the guinea pig cochlea, a 1.5- to 3-fold increase in the drug exposure time of NPs-CS/GP was found than those of the solution, NPs and IFN-loaded hydrogel. Most importantly, a prolonged residence time was attained without obvious histological changes in the inner ear. This biodegradable, injectable, and thermosensitive NPs-CS/GP system may allow longer delivery of protein drugs to the inner ear, thus may be a potential novel vehicle for inner ear therapy.

Novel dipeptide nanoparticles for effective curcumin delivery

Directory of Open Access Journals (Sweden)

Alam S

2012-08-01

Full Text Available Shadab Alam,* Jiban J Panda,* Virander S Chauhan International Centre for Genetic Engineering and Biotechnology, New Delhi, India*Both authors contributed equally to this workBackground: Curcumin, the principal curcuminoid of the popular Indian spice turmeric, has a wide spectrum of pharmaceutical properties such as antitumor, antioxidant, antiamyloid, and anti-inflammatory activity. However, poor aqueous solubility and low bioavailability of curcumin is a major challenge in its development as a useful drug. To enhance the aqueous solubility and bioavailability of curcumin, attempts have been made to encapsulate it in liposomes, polymeric nanoparticles (NPs, lipid-based NPs, biodegradable microspheres, cyclodextrin, and hydrogels.Methods: In this work, we attempted to entrap curcumin in novel self-assembled dipeptide NPs containing a nonprotein amino acid, α,β-dehydrophenylalanine, and investigated the biological activity of dipeptide-curcumin NPs in cancer models both in vitro and in vivo.Results: Of the several dehydrodipeptides tested, methionine-dehydrophenylalanine was the most suitable one for loading and release of curcumin. Loading of curcumin in the dipeptide NPs increased its solubility, improved cellular availability, enhanced its toxicity towards different cancerous cell lines, and enhanced curcumin’s efficacy towards inhibiting tumor growth in Balb/c mice bearing a B6F10 melanoma tumor.Conclusion: These novel, highly biocompatible, and easy to construct dipeptide NPs with a capacity to load and release curcumin in a sustained manner significantly improved curcumin’s cellular uptake without altering its anticancer or other therapeutic properties. Curcumin-dipeptide NPs also showed improved in vitro and in vivo chemotherapeutic efficacy compared to curcumin alone. Such dipeptide-NPs may also improve the delivery of other potent hydrophobic drug molecules that show poor cellular uptake, bioavailability, and efficacy

Plasmon enhanced water splitting mediated by hybrid bimetallic Au-Ag core-shell nanostructures.

Science.gov (United States)

Erwin, William R; Coppola, Andrew; Zarick, Holly F; Arora, Poorva; Miller, Kevin J; Bardhan, Rizia

2014-11-07

In this work, we employed wet chemically synthesized bimetallic Au-Ag core-shell nanostructures (Au-AgNSs) to enhance the photocurrent density of mesoporous TiO2 for water splitting and we compared the results with monometallic Au nanoparticles (AuNPs). While Au-AgNSs incorporated photoanodes give rise to 14× enhancement in incident photon to charge carrier efficiency, AuNPs embedded photoanodes result in 6× enhancement. By varying nanoparticle concentration in the photoanodes, we observed ∼245× less Au-AgNSs are required relative to AuNPs to generate similar photocurrent enhancement for solar fuel conversion. Power-dependent measurements of Au-AgNSs and AuNPs showed a first order dependence to incident light intensity, relative to half-order dependence for TiO2 only photoanodes. This indicated that plasmonic nanostructures enhance charge carriers formed on the surface of the TiO2 which effectively participate in photochemical reactions. Our experiments and simulations suggest the enhanced near-field, far-field, and multipolar resonances of Au-AgNSs facilitating broadband absorption of solar radiation collectively gives rise to their superior performance in water splitting.

Green Synthesis of AgNPs Stabilized with biowaste and their antimicrobial activities

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Nakuleshwar Dut Jasuja

2014-12-01

Full Text Available In the present study, rapid reduction and stabilization of Ag+ ions with different NaOH molar concentration (0.5 mM, 1.0 mM and 1.5 mM has been carried out in the aqueous solution of silver nitrate by the bio waste peel extract of P.granatum. Generally, chemical methods used for the synthesis of AgNPs are quite toxic, flammable and have adverse effect in medical application but green synthesis is a better option due to eco-friendliness, non-toxicity and safe for human. Stable AgNPs were synthesized by treating 90 mL aqueous solution of 2 mM AgNO3 with the 5 mL plant peels extract (0.4% w/v at different NaOH concentration (5 mL. The synthesized AgNPs were characterized by UV-Vis spectroscopy, TEM and SEM. Further, antimicrobial activities of AgNPs were performed on Gram positive i.e. Staphylococcus aureus, Bacillus subtilius and Gram negative i.e. E. coli, Pseudomonas aeruginosa bacteria. The AgNPs synthesized at 1.5 mM NaOH concentration had shown maximum zone of inhibition (ZOI i.e. 49 ± 0.64 in E. coli, whereas Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus subtilius had shown 40 ± 0.29 mm, 28 ± 0.13 and 42 ± 0.49 mm ZOI respectively. The MIC value of 30 g/mL observed for E. coli Whereas, Staphylococcus aureus, Bacillus subtilius and Pseudomonas aeruginosa had shown 45 µg/mL, 38 µg/mL, 35 µg/mL respectively. The study revealed that AgNPs had shown significant antimicrobial activity as compared to Streptomycin.

Quantum dynamical simulations of local field enhancement in metal nanoparticles.

Science.gov (United States)

Negre, Christian F A; Perassi, Eduardo M; Coronado, Eduardo A; Sánchez, Cristián G

2013-03-27

Field enhancements (Γ) around small Ag nanoparticles (NPs) are calculated using a quantum dynamical simulation formalism and the results are compared with electrodynamic simulations using the discrete dipole approximation (DDA) in order to address the important issue of the intrinsic atomistic structure of NPs. Quite remarkably, in both quantum and classical approaches the highest values of Γ are located in the same regions around single NPs. However, by introducing a complete atomistic description of the metallic NPs in optical simulations, a different pattern of the Γ distribution is obtained. Knowing the correct pattern of the Γ distribution around NPs is crucial for understanding the spectroscopic features of molecules inside hot spots. The enhancement produced by surface plasmon coupling is studied by using both approaches in NP dimers for different inter-particle distances. The results show that the trend of the variation of Γ versus inter-particle distance is different for classical and quantum simulations. This difference is explained in terms of a charge transfer mechanism that cannot be obtained with classical electrodynamics. Finally, time dependent distribution of the enhancement factor is simulated by introducing a time dependent field perturbation into the Hamiltonian, allowing an assessment of the localized surface plasmon resonance quantum dynamics.

TAF11 Assembles the RISC Loading Complex to Enhance RNAi Efficiency.

Science.gov (United States)

Liang, Chunyang; Wang, Yibing; Murota, Yukiko; Liu, Xiang; Smith, Dean; Siomi, Mikiko C; Liu, Qinghua

2015-09-03

Assembly of the RNA-induced silencing complex (RISC) requires formation of the RISC loading complex (RLC), which contains the Dicer-2 (Dcr-2)-R2D2 complex and recruits duplex siRNA to Ago2 in Drosophila melanogaster. However, the precise composition and action mechanism of Drosophila RLC remain unclear. Here we identified the missing factor of RLC as TATA-binding protein-associated factor 11 (TAF11) by genetic screen. Although it is an annotated nuclear transcription factor, we found that TAF11 also associated with Dcr-2/R2D2 and localized to cytoplasmic D2 bodies. Consistent with defective RLC assembly in taf11(-/-) ovary extract, we reconstituted the RLC in vitro using the recombinant Dcr-2-R2D2 complex, TAF11, and duplex siRNA. Furthermore, we showed that TAF11 tetramer facilitates Dcr-2-R2D2 tetramerization to enhance siRNA binding and RISC loading activities. Together, our genetic and biochemical studies define the molecular nature of the Drosophila RLC and elucidate a cytoplasmic function of TAF11 in organizing RLC assembly to enhance RNAi efficiency. Copyright © 2015 Elsevier Inc. All rights reserved.

Mechanism of giant enhancement of light emission from Au/CdSe nanocomposites

International Nuclear Information System (INIS)

Hsieh, Y-P; Liang, C-T; Chen, Y-F; Lai, C-W; Chou, P-T

2007-01-01

Based on the enhanced electron-hole recombination rate generated by surface plasmon (SP) waves of Au nanoparticles (NPs) and electrons transferred from CdSe quantum dots (QDs) to Au NPs, we propose a mechanism to elucidate the luminescent behavior in Au and CdSe nanocomposites. With our proposed model, the enhancement of the spectrally integrated PL intensity can be manipulated by up to a factor of ∼33, the largest value ever reported. Our study can be used to clarify the ambiguity in controlling the light emission enhancement and quenching of semiconductor nanocrystals coupled with the SP waves of metal NPs. It should be very useful for the creation of highly efficient solid-state emitters

APT LLRF control system functionality and architecture

International Nuclear Information System (INIS)

Regan, A.H.; Rohlev, A.S.; Ziomek, C.D.

1996-01-01

The low-level RF (LLRF) control system for the Accelerator Production of Tritium (APT) will perform various functions. Foremost is the feedback control of the accelerating fields within the cavity in order to maintain field stability within ± 1% amplitude and 1 degree phase. The feedback control system requires a phase-stable RF reference subsystem signal to correctly phase each cavity. Also, instead of a single klystron RF source for individual accelerating cavities, multiple klystrons will drive a string of resonantly coupled cavities, based on input from a single LLRF feedback control system. To achieve maximum source efficiency, we will be employing single fast feedback controls around individual klystrons such that the gain and phase characteristics of each will be 'identical'. In addition, the resonance condition of the cavities is monitored and maintained. To quickly respond to RF shutdowns, and hence rapid accelerating cavity cool-down, due to RF fault conditions, drive frequency agility in the main feedback control subsystem will also be incorporated. Top level block diagrams will be presented and described as they will first be developed and demonstrated on the Low Energy Demonstrator Accelerator (LEDA). (author)

Discovery and in Vivo Evaluation of Novel RGD-Modified Lipid-Polymer Hybrid Nanoparticles for Targeted Drug Delivery

Directory of Open Access Journals (Sweden)

Yinbo Zhao

2014-09-01

Full Text Available In the current study, the lipid-shell and polymer-core hybrid nanoparticles (lpNPs modified by Arg–Gly–Asp(RGD peptide, loaded with curcumin (Cur, were developed by emulsification-solvent volatilization method. The RGD-modified hybrid nanoparticles (RGD–lpNPs could overcome the poor water solubility of Cur to meet the requirement of intravenous administration and tumor active targeting. The obtained optimal RGD-lpNPs, composed of PLGA (poly(lactic-co-glycolic acid–mPEG (methoxyl poly(ethylene- glycol, RGD–polyethylene glycol (PEG–cholesterol (Chol copolymers and lipids, had good entrapment efficiency, submicron size and negatively neutral surface charge. The core-shell structure of RGD–lpNPs was verified by TEM. Cytotoxicity analysis demonstrated that the RGD–lpNPs encapsulated Cur retained potent anti-tumor effects. Flow cytometry analysis revealed the cellular uptake of Cur encapsulated in the RGD–lpNPs was increased for human umbilical vein endothelial cells (HUVEC. Furthermore, Cur loaded RGD–lpNPs were more effective in inhibiting tumor growth in a subcutaneous B16 melanoma tumor model. The results of immunofluorescent and immunohistochemical studies by Cur loaded RGD–lpNPs therapies indicated that more apoptotic cells, fewer microvessels, and fewer proliferation-positive cells were observed. In conclusion, RGD–lpNPs encapsulating Cur were developed with enhanced anti-tumor activity in melanoma, and Cur loaded RGD–lpNPs represent an excellent tumor targeted formulation of Cur which might be an attractive candidate for cancer therapy.

Discovery and in vivo evaluation of novel RGD-modified lipid-polymer hybrid nanoparticles for targeted drug delivery.

Science.gov (United States)

Zhao, Yinbo; Lin, Dayong; Wu, Fengbo; Guo, Li; He, Gu; Ouyang, Liang; Song, Xiangrong; Huang, Wei; Li, Xiang

2014-09-29

In the current study, the lipid-shell and polymer-core hybrid nanoparticles (lpNPs) modified by Arg-Gly-Asp(RGD) peptide, loaded with curcumin (Cur), were developed by emulsification-solvent volatilization method. The RGD-modified hybrid nanoparticles (RGD-lpNPs) could overcome the poor water solubility of Cur to meet the requirement of intravenous administration and tumor active targeting. The obtained optimal RGD-lpNPs, composed of PLGA (poly(lactic-co-glycolic acid))-mPEG (methoxyl poly(ethylene- glycol)), RGD-polyethylene glycol (PEG)-cholesterol (Chol) copolymers and lipids, had good entrapment efficiency, submicron size and negatively neutral surface charge. The core-shell structure of RGD-lpNPs was verified by TEM. Cytotoxicity analysis demonstrated that the RGD-lpNPs encapsulated Cur retained potent anti-tumor effects. Flow cytometry analysis revealed the cellular uptake of Cur encapsulated in the RGD-lpNPs was increased for human umbilical vein endothelial cells (HUVEC). Furthermore, Cur loaded RGD-lpNPs were more effective in inhibiting tumor growth in a subcutaneous B16 melanoma tumor model. The results of immunofluorescent and immunohistochemical studies by Cur loaded RGD-lpNPs therapies indicated that more apoptotic cells, fewer microvessels, and fewer proliferation-positive cells were observed. In conclusion, RGD-lpNPs encapsulating Cur were developed with enhanced anti-tumor activity in melanoma, and Cur loaded RGD-lpNPs represent an excellent tumor targeted formulation of Cur which might be an attractive candidate for cancer therapy.

AptRank: an adaptive PageRank model for protein function prediction on   bi-relational graphs.

Science.gov (United States)

Jiang, Biaobin; Kloster, Kyle; Gleich, David F; Gribskov, Michael

2017-06-15

Diffusion-based network models are widely used for protein function prediction using protein network data and have been shown to outperform neighborhood-based and module-based methods. Recent studies have shown that integrating the hierarchical structure of the Gene Ontology (GO) data dramatically improves prediction accuracy. However, previous methods usually either used the GO hierarchy to refine the prediction results of multiple classifiers, or flattened the hierarchy into a function-function similarity kernel. No study has taken the GO hierarchy into account together with the protein network as a two-layer network model. We first construct a Bi-relational graph (Birg) model comprised of both protein-protein association and function-function hierarchical networks. We then propose two diffusion-based methods, BirgRank and AptRank, both of which use PageRank to diffuse information on this two-layer graph model. BirgRank is a direct application of traditional PageRank with fixed decay parameters. In contrast, AptRank utilizes an adaptive diffusion mechanism to improve the performance of BirgRank. We evaluate the ability of both methods to predict protein function on yeast, fly and human protein datasets, and compare with four previous methods: GeneMANIA, TMC, ProteinRank and clusDCA. We design four different validation strategies: missing function prediction, de novo function prediction, guided function prediction and newly discovered function prediction to comprehensively evaluate predictability of all six methods. We find that both BirgRank and AptRank outperform the previous methods, especially in missing function prediction when using only 10% of the data for training. The MATLAB code is available at https://github.rcac.purdue.edu/mgribsko/aptrank . gribskov@purdue.edu. Supplementary data are available at Bioinformatics online. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com

Engineering Plasmonic Nanopillar Arrays for Surface-enhanced Raman Spectroscopy

DEFF Research Database (Denmark)

Wu, Kaiyu

This Ph.D. thesis presents (i) an in-depth understanding of the localized surface plasmon resonances (LSPRs) in the nanopillar arrays (NPs) for surface-enhanced Raman spectroscopy (SERS), and (ii) systematic ways of optimizing the fabrication process of NPs to improve their SERS efficiencies. Thi...

Potential of Biosynthesized Silver Nanoparticles as Nanocatalyst for Enhanced Degradation of Cellulose by Cellulase

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Bipinchandra K. Salunke

2015-01-01

Full Text Available Silver nanoparticles (AgNPs as a result of their excellent optical and electronic properties are promising catalytic materials for various applications. In this study, we demonstrate a novel approach for enhanced degradation of cellulose using biosynthesized AgNPs in an enzyme catalyzed reaction of cellulose hydrolysis by cellulase. AgNPs were synthesized through reduction of silver nitrate by extracts of five medicinal plants (Mentha arvensis var. piperascens, Buddleja officinalis Maximowicz, Epimedium koreanum Nakai, Artemisia messer-schmidtiana Besser, and Magnolia kobus. An increase of around twofold in reducing sugar formation confirmed the catalytic activity of AgNPs as nanocatalyst. The present study suggests that immobilization of the enzyme onto the surface of the AgNPs can be useful strategy for enhanced degradation of cellulose, which can be utilized for diverse industrial applications.

Annealing time dependent up-conversion luminescence enhancement in magnesium–tellurite glass

Energy Technology Data Exchange (ETDEWEB)

Amjad, Raja J., E-mail: rajajunaid25@gmail.com [Advanced Optical Material Research Group, Faculty of Science, Universiti Teknologi Malaysia, Skudai, Johor bahru 81310 (Malaysia); Centre for Solid State Physics, University of the Punjab, QAC, Lahore 54590 (Pakistan); Sahar, M.R.; Ghoshal, S.K.; Dousti, M.R. [Advanced Optical Material Research Group, Faculty of Science, Universiti Teknologi Malaysia, Skudai, Johor bahru 81310 (Malaysia); Riaz, S. [Centre for Solid State Physics, University of the Punjab, QAC, Lahore 54590 (Pakistan); Samavati, A.R.; Arifin, R. [Advanced Optical Material Research Group, Faculty of Science, Universiti Teknologi Malaysia, Skudai, Johor bahru 81310 (Malaysia); Naseem, S. [Centre for Solid State Physics, University of the Punjab, QAC, Lahore 54590 (Pakistan)

2013-04-15

Silver nanoparticles (NPs) embedded Er{sup 3+} ions doped magnesium–tellurite glasses are prepared using melt quenching technique. Heat treatment with different time intervals above the glass transition temperature is applied in order to reduce the silver ions (Ag{sup +}) to silver NPs (Ag{sup o}). The transmission electron microscopy (TEM), differential thermal analyses (DTA), UV–vis-NIR absorption spectroscopy and photoluminescence (PL) spectroscopy are used to examine annealing time dependent structural and optical properties. The characteristics temperatures such as glass transition temperature (T{sub g}), crystallization temperature (T{sub c}) and melting temperature (T{sub m}) obtained from DTA for an as prepared sample are 322 °C, 450 °C and 580 °C, respectively. TEM image clearly shows the homogeneous distribution of silver NPs with an average diameter ∼12 nm. The observed localized surface plasmon resonance (LSPR) band is evidenced at 534 nm. Furthermore, the infrared to visible frequency up-conversion (UC) emission under 786 nm excitation exhibits three emission bands centered at 532 nm, 554 nm and 634 nm corresponding to {sup 2}H{sub 11/2}→{sup 4}I{sub 15/2}, {sup 4}S{sub 3/2}→{sup 4}I{sub 15/2} and {sup 4}F{sub 9/2}→{sup 4}I{sub 15/2} transitions of Er{sup 3+}, respectively. Intensity of all the bands is found to enhance by increasing the annealing time up to 24 h. However, further increase in the annealing time duration (∼40 h) reduces the intensity. Enhancement in the luminescence intensity is understood in terms of the local field effect of the silver NPs whereas the quenching is attributed to the energy transfer from Er{sup 3+} ions to silver NPs. -- Highlights: ► Er{sup 3+}-doped silver NPs embedded magnesium–tellurite glasses are prepared. ► TEM confirms the successful precipitation of spherical NPs by heat treatment (HT). ► Luminescence is enhanced due to the growth of NPs after HT up to 24 h. ► With HT>24 h (40 h

Green synthesized conditions impacting on the reactivity of Fe NPs for the degradation of malachite green.

Science.gov (United States)

Huang, Lanlan; Luo, Fang; Chen, Zuliang; Megharaj, Mallavarapu; Naidu, Ravendra

2015-02-25

This study investigates green tea extract synthesized conditions impacting on the reactivity of iron nanoparticles (Fe NPs) used for the degradation of malachite green (MG), including the volume ratio of Fe(2+) and tea extract, the solution pH and temperature. Results indicated that the reactivity of Fe NPs increased with higher temperature, but fell with increasing pH and the volume ratio of Fe(2+) and tea extract. Scanning electron microscope (SEM), energy-dispersive spectrometer (EDS), Fourier transform infrared spectroscope (FTIR) and X-ray diffraction (XRD) indicated that Fe NPs were spherical in shape, their diameter was 70-80 nm and they were mainly composed of iron oxide nanoparticles. UV-visible (UV-vis) indicated that reactivity of Fe NPs used in degradation of MG significantly depended on the synthesized conditions of Fe NPs. This was due to their impact on the reactivity and morphology of Fe NPs. Finally, degradation of MG showed that 90.56% of MG was removed using Fe NPs. Copyright © 2014 Elsevier B.V. All rights reserved.

Highly active surface-enhanced Raman scattering (SERS) substrates based on gold nanoparticles infiltrated into SiO{sub 2} inverse opals

Energy Technology Data Exchange (ETDEWEB)

Ankudze, Bright; Philip, Anish [Department of Chemistry, University of Eastern Finland, P.O. Box 111, F1-80101, Joensuu (Finland); Pakkanen, Tuula T., E-mail: Tuula.Pakkanen@uef.fi [Department of Chemistry, University of Eastern Finland, P.O. Box 111, F1-80101, Joensuu (Finland); Matikainen, Antti; Vahimaa, Pasi [Institute of Photonics, University of Eastern Finland, P.O. Box 111, F1-80101, Joensuu (Finland)

2016-11-30

Highlights: • SERS substrates prepared by infiltration of nanoparticles into SiO{sub 2} inverse opal. • The SERS substrate gives an enhancement factor of 10{sup 7} for 4-aminothiophenol. • The sensitivity of the substrate is mainly attributed to gold nanoparticle clusters. - Abstract: SiO{sub 2} inverse opal (IO) films with embedded gold nanoparticles (AuNPs) for surface-enhanced Raman scattering (SERS) application are reported. SiO{sub 2} IO films were loaded with AuNPs by a simple infiltration in a single cycle to form Au-SiO{sub 2} IOs. The optical property and the morphology of the Au-SiO{sub 2} IO substrates were characterized; it was observed that they retained the Bragg diffraction of SiO{sub 2} IO and the localized surface plasmon resonance (LSPR) of AuNPs. The SERS property of the Au-SiO{sub 2} IO substrates were studied with methylene blue (MB) and 4-aminothiophenol (4-ATP). The SERS enhancement factors were 10{sup 7} and 10{sup 6} for 4-ATP and MB, respectively. A low detection limit of 10{sup −10} M for 4-ATP was also obtained with the Au-SiO{sub 2} IO substrate. A relative standard deviation of 18.5% for the Raman signals intensity at 1077 cm{sup −1} for 4-ATP shows that the Au-SiO{sub 2} IO substrates have good signal reproducibility. The results of this study indicate that the Au-SiO{sub 2} IO substrates can be used in sensing and SERS applications.

Design of 250-MW CW RF system for APT

International Nuclear Information System (INIS)

Rees, D.

1997-01-01

The design for the RF systems for the APT (Accelerator Production of Tritium) proton linac will be presented. The linac produces a continuous beam power of 130 MW at 1300 MeV with the installed capability to produce up to a 170 MW beam at 1700 MeV. The linac is comprised of a 350 MHz RFQ to 7 MeV followed in sequence by a 700 MHz coupled-cavity drift tube linac, coupled-cavity linac, and superconducting (SC) linac to 1700 MeV. At the 1700 MeV, 100 mA level the linac requires 213 MW of continuous-wave (CW) RF power. This power will be supplied by klystrons with a nominal output power of 1.0 MW. 237 kystrons are required with all but three of these klystrons operating at 700 MHz. The klystron count includes redundancy provisions that will be described which allow the RF systems to meet an operational availability in excess of 95 percent. The approach to achieve this redundancy will be presented for both the normal conducting (NC) and SC accelerators. Because of the large amount of CW RF power required for the APT linac, efficiency is very important to minimize operating cost. Operation and the RF system design, including in-progress advanced technology developments which improve efficiency, will be discussed. RF system performance will also be predicted. Because of the simultaneous pressures to increase RF system reliability, reduce tunnel envelope, and minimize RF system cost, the design of the RF vacuum windows has become an important issue. The power from a klystron will be divided into four equal parts to minimize the stress on the RF vacuum windows. Even with this reduction, the RF power level at the window is at the upper boundary of the power levels employed at other CW accelerator facilities. The design of a 350 MHz, coaxial vacuum window will be presented as well as test results and high power conditioning profiles. The transmission of 950 kW, CW, power through this window has been demonstrated with only minimal high power conditioning

Bufalin-loaded mPEG-PLGA-PLL-cRGD nanoparticles: preparation, cellular uptake, tissue distribution, and anticancer activity

Directory of Open Access Journals (Sweden)

Duan YR

2012-07-01

Full Text Available Peihao Yin,1,* Yan Wang,1,* YanYan Qiu,1 LiLi Hou,1 Xuan Liu,1 Jianmin Qin,1 Yourong Duan,2 Peifeng Liu,2 Ming Qiu,3 Qi Li11Department of Clinical Oncology, Putuo Hospital and Interventional Cancer Institute of Integrative Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China; 2Shanghai Cancer Institute, Jiaotong University, Shanghai, China; 3Department of General Surgery, Changzheng Hospital, Second Military Medical University, Shanghai, China *These authors contributed equally to this workBackground: Recent studies have shown that bufalin has a good antitumor effect but has high toxicity, poor water solubility, a short half-life, a narrow therapeutic window, and a toxic dose that is close to the therapeutic dose, which all limit its clinical application. This study aimed to determine the targeting efficacy of nanoparticles (NPs made of methoxy polyethylene glycol (mPEG, polylactic-co-glycolic acid (PLGA, poly-L-lysine (PLL, and cyclic arginine-glycine-aspartic acid (cRGD loaded with bufalin, ie, bufalin-loaded mPEG-PLGA-PLL-cRGD nanoparticles (BNPs, in SW620 colon cancer-bearing mice.Methods: BNPs showed uniform size. The size, shape, zeta potential, drug loading, encapsulation efficiency, and release of these nanoparticles were studied in vitro. The tumor targeting, cellular uptake, and growth-inhibitory effect of BNPs in vivo were tested.Results: BNPs were of uniform size with an average particle size of 164 ± 84 nm and zeta potential of 2.77 mV. The encapsulation efficiency was 81.7% ± 0.89%, and the drug load was 3.92% ± 0.16%. The results of in vitro cytotoxicity studies showed that although the blank NPs were nontoxic, they enhanced the cytotoxicity of bufalin in BNPs. Drug release experiments showed that the release of the drug was prolonged and sustained. The results of confocal laser scanning microscopy indicated that BNPs could effectively bind to human umbilical vein endothelial cells. In the SW620

Rainfall Deduction Method for Estimating Non-Point Source Pollution Load for Watershed

OpenAIRE

Cai, Ming; Li, Huai-en; KAWAKAMI, Yoji

2004-01-01

The water pollution can be divided into point source pollution (PSP) and non-point source pollution (NSP). Since the point source pollution has been controlled, the non-point source pollution is becoming the main pollution source. The prediction of NSP load is being increasingly important in water pollution controlling and planning in watershed. Considering the monitoring data shortage of NPS in China, a practical estimation method of non-point source pollution load --- rainfall deduction met...

Exploring the Behavior and Metabolic Transformations of SeNPs in Exposed Lactic Acid Bacteria. Effect of Nanoparticles Coating Agent

Directory of Open Access Journals (Sweden)

Maria Palomo-Siguero

2017-08-01

Full Text Available The behavior and transformation of selenium nanoparticles (SeNPs in living systems such as microorganisms is largely unknown. To address this knowledge gap, we examined the effect of three types of SeNP suspensions toward Lactobacillus delbrueckii subsp. bulgaricus LB-12 using a variety of techniques. SeNPs were synthesized using three types of coating agents (chitosan (CS-SeNPs, hydroxyethyl cellulose (HEC-SeNPs and a non-ionic surfactant, surfynol (ethoxylated-SeNPs. Morphologies of SeNPs were all spherical. Transmission electron microscopy (TEM was used to locate SeNPs in the bacteria. High performance liquid chromatography (HPLC on line coupled to inductively coupled plasma mass spectrometry (ICP-MS was applied to evaluate SeNP transformation by bacteria. Finally, flow cytometry employing the live/dead test and optical density measurements at 600 nm (OD600 were used for evaluating the percentages of bacteria viability when supplementing with SeNPs. Negligible damage was detected by flow cytometry when bacteria were exposed to HEC-SeNPs or CS-SeNPs at a level of 10 μg Se mL−1. In contrast, ethoxylated-SeNPs were found to be the most harmful nanoparticles toward bacteria. CS-SeNPs passed through the membrane without causing damage. Once inside, SeNPs were metabolically transformed to organic selenium compounds. Results evidenced the importance of capping agents when establishing the true behavior of NPs.

Eco-friendly biosynthesis, anticancer drug loading and cytotoxic effect of capped Ag-nanoparticles against breast cancer

Science.gov (United States)

Naz, M.; Nasiri, N.; Ikram, M.; Nafees, M.; Qureshi, M. Z.; Ali, S.; Tricoli, A.

2017-11-01

The work aimed to prepare silver nanoparticles (Ag-NPs) from silver nitrate and various concentrations of the seed extract ( Setaria verticillata) by a green synthetic route. The chemical and physical properties of the resulting Ag-NPs were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectrometry and ultraviolet-visible (UV-Vis) spectrophotometry. Anticancer activity of Ag-NPs (5-20 nm) had dose-dependent cytotoxic effect against breast cancer (MCF7-FLV) cells. The in vitro toxicity was studied on adult earthworms (Lumbricina) resulting in statistically significant ( P < 0.05) inhibition. The prepared NPs were loaded with hydrophilic anticancer drugs (ACD), doxorubicin (DOX) and daunorubicin (DNR), for developing a novel drug delivery carrier having significant adsorption capacity and efficiency to remove the side effects of the medicines effective for leukemia chemotherapy.

Concentration-dependent, size-independent toxicity of citrate capped AuNPs in Drosophila melanogaster.

Directory of Open Access Journals (Sweden)

Giuseppe Vecchio

Full Text Available The expected potential benefits promised by nanotechnology in various fields have led to a rapid increase of the presence of engineered nanomaterials in a high number of commercial goods. This is generating increasing questions about possible risks for human health and environment, due to the lack of an in-depth assessment of the physical/chemical factors responsible for their toxic effects. In this work, we evaluated the toxicity of monodisperse citrate-capped gold nanoparticles (AuNPs of different sizes (5, 15, 40, and 80 nm in the model organism Drosophila melanogaster, upon ingestion. To properly evaluate and distinguish the possible dose- and/or size-dependent toxicity of the AuNPs, we performed a thorough assessment of their biological effects, using two different dose-metrics. In the first approach, we kept constant the total surface area of the differently sized AuNPs (Total Exposed Surface area approach, TES, while, in the second approach, we used the same number concentration of the four different sizes of AuNPs (Total Number of Nanoparticles approach, TNN. We observed a significant AuNPs-induced toxicity in vivo, namely a strong reduction of Drosophila lifespan and fertility performance, presence of DNA fragmentation, as well as a significant modification in the expression levels of genes involved in stress responses, DNA damage recognition and apoptosis pathway. Interestingly, we found that, within the investigated experimental conditions, the toxic effects in the exposed organisms were directly related to the concentration of the AuNPs administered, irrespective of their size.

Optimization of enhanced biological phosphorus removal after periods of low loading.

Science.gov (United States)

Miyake, Haruo; Morgenroth, Eberhard

2005-01-01

Enhanced biological phosphorus removal is a well-established technology for the treatment of municipal wastewater. However, increased effluent phosphorus concentrations have been reported after periods (days) of low organic loading. The purpose of this study was to evaluate different operating strategies to prevent discharge of effluent after such low-loading periods. Mechanisms leading to these operational problems have been related to the reduction of polyphosphate-accumulating organisms (PAOs) and their storage compounds (polyhydroxy alkanoates [PHA]). Increased effluent phosphorus concentrations can be the result of an imbalance between influent loading and PAOs in the system and an imbalance between phosphorus release and uptake rates. The following operating conditions were tested in their ability to prevent a reduction of PHA and of overall biomass during low organic loading conditions: (a) unchanged operation, (b) reduced aeration time, (c) reduced sludge wastage, and (d) combination of reduced aeration time and reduced sludge wastage. Experiments were performed in a laboratory-scale anaerobic-aerobic sequencing batch reactor, using acetate as the carbon source. Without operational adjustments, phosphorus-release rates decreased during low-loading periods but recovered rapidly. Phosphorus-uptake rates also decreased, and the recovery typically required several days to increase to normal levels. The combination of reduced aeration time and reduced sludge wastage allowed the maintenance of constant levels of both PHA and overall biomass. A mathematical model was used to explain the influence of the tested operating conditions on PAO and PHA concentrations. While experimental results were in general agreement with model predictions, the kinetic expression for phosphorus uptake deviated significantly for the first 24 hours after low-loading conditions. Mechanisms leading to these deviations need to be further investigated.

Three-dimensional nanoporous MoS2 framework decorated with Au nanoparticles for surface-enhanced Raman scattering

Science.gov (United States)

Sheng, Yingqiang; Jiang, Shouzhen; Yang, Cheng; Liu, Mei; Liu, Aihua; Zhang, Chao; Li, Zhen; Huo, Yanyan; Wang, Minghong; Man, Baoyuan

2017-08-01

The three-dimensional (3D) MoS2 decorated with Au nanoparticles (Au NPs) hybrids (3D MoS2-Au NPs) for surface-enhanced Raman scattering (SERS) sensing was demonstrated in this paper. SEM, Raman spectroscopy, TEM, SAED, EDX and XRD were performed to characterize 3D MoS2-Au NPs hybrids. Rhodamine 6G (R6G), fluorescein and gallic acid molecules were used as the probe for the SERS detection of the 3D MoS2-Au NPs hybrids. In addition, we modeled the enhancement of the electric field of MoS2-Au NPs hybrids using Finite-difference time-domain (FDTD) analysis, which can further give assistance to the mechanism understanding of the SERS activity.

Sodium selenite/selenium nanoparticles (SeNPs) protect cardiomyoblasts and zebrafish embryos against ethanol induced oxidative stress.

Science.gov (United States)

Kalishwaralal, Kalimuthu; Jeyabharathi, Subhaschandrabose; Sundar, Krishnan; Muthukumaran, Azhaguchamy

2015-10-01

Alcoholic cardiomyopathy is the damage caused to the heart muscles due to high level of alcohol consumption resulting in enlargement and inflammation of the heart. Selenium is an important trace element that is beneficial to human health. Selenium protects the cells by preventing the formation of free radicals in the body. In the present study, protein mediated synthesis of SeNPs was investigated. Two different sizes of SeNPs were synthesized using BSA and keratin. The synthesized SeNPs were characterized by scanning electron microscopy (SEM) with elemental composition analysis Energy Dispersive X-ray spectroscopy(EDX) and X-ray diffraction (XRD). This study demonstrates the in vitro and in vivo antioxidative effects of sodium selenite and SeNPs. Further selenium and SeNPs were evaluated for their ability to protect against 1% ethanol induced oxidative stress in H9C2 cell line. The selenium and SeNPs were found to reduce the 1% ethanol-induced oxidative damage through scavenging intracellular reactive oxygen species. The selenium and SeNPs could also prevent pericardial edema induced ethanol treatment and reduced apoptosis and cell death in zebrafish embryos. The results indicate that selenium and SeNPs could potentially be used as an additive in alcoholic beverage industry to control the cardiomyopathy. Copyright © 2015 Elsevier GmbH. All rights reserved.

Transferrin-conjugated magnetic dextran-spermine nanoparticles for targeted drug transport across blood-brain barrier.

Science.gov (United States)

Ghadiri, Maryam; Vasheghani-Farahani, Ebrahim; Atyabi, Fatemeh; Kobarfard, Farzad; Mohamadyar-Toupkanlou, Farzaneh; Hosseinkhani, Hossein

2017-10-01

Application of many vital hydrophilic medicines have been restricted by blood-brain barrier (BBB) for treatment of brain diseases. In this study, a targeted drug delivery system based on dextran-spermine biopolymer was developed for drug transport across BBB. Drug loaded magnetic dextran-spermine nanoparticles (DS-NPs) were prepared via ionic gelation followed by transferrin (Tf) conjugation as targeting moiety. The characteristics of Tf conjugated nanoparticles (TDS-NPs) were analyzed by different methods and their cytotoxicity effects on U87MG cells were tested. The superparamagnetic characteristic of TDS-NPs was verified by vibration simple magnetometer. Capecitabine loaded TDS-NPs exhibited pH-sensitive release behavior with enhanced cytotoxicity against U87MG cells, compared to DS-NPs and free capecitabine. Prussian-blue staining and TEM-imaging showed the significant cellular uptake of TDS-NPs. Furthermore, a remarkable increase of Fe concentrations in brain was observed following their biodistribution and histological studies in vivo, after 1 and 7 days of post-injection. Enhanced drug transport across BBB and pH-triggered cellular uptake of TDS-NPs indicated that these theranostic nanocarriers are promising candidate for the brain malignance treatment. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 2851-2864, 2017. © 2017 Wiley Periodicals, Inc.

Copper oxide loaded PLGA nanospheres: towards a multifunctional nanoscale platform for ultrasound-based imaging and therapy

Science.gov (United States)

Perlman, Or; Weitz, Iris S.; Sivan, Sarit S.; Abu-Khalla, Hiba; Benguigui, Madeleine; Shaked, Yuval; Azhari, Haim

2018-05-01

Copper oxide nanoparticles (CuO-NPs) are increasingly becoming the subject of investigation exploring their potential use for diagnostic and therapeutic purposes. Recent work has demonstrated their anticancer potential, as well as contrast agent capabilities for magnetic resonance imaging (MRI) and through-transmission ultrasound. However, no capability of CuO-NPs has been demonstrated using conventional ultrasound systems, which, unlike the former, are widely deployed in the clinic. Furthermore, in spite of their potential as multifunctional nano-based materials for diagnosis and therapy, CuO-NPs have been delayed from further clinical application due to their inherent toxicity. Herein, we present the synthesis of a novel nanoscale system, composed of CuO-loaded PLGA nanospheres (CuO-PLGA-NS), and demonstrate its imaging detectability and augmented heating effect by therapeutic ultrasound. The CuO-PLGA-NS were prepared by a double emulsion (W/O/W) method with subsequent solvent evaporation. They were characterized as sphere-shaped, with size approximately 200 nm. Preliminary results showed that the viability of PANC-1, human pancreatic adenocarcinoma cells was not affected after 72 h exposure to CuO-PLGA-NS, implying that PLGA masks the toxic effects of CuO-NPs. A systematic ultrasound imaging evaluation of CuO-PLGA-NS, using a conventional system, was performed in vitro and ex vivo using poultry heart and liver, and also in vivo using mice, all yielding a significant contrast enhancement. In contrast to CuO-PLGA-NS, neither bare CuO-NPs nor blank PLGA-NS possess these unique advantageous ultrasonic properties. Furthermore, CuO-PLGA-NS accelerated ultrasound-induced temperature elevation by more than 4 °C within 2 min. The heating efficiency (cumulative equivalent minutes at 43 °C) was increased approximately six-fold, demonstrating the potential for improved ultrasound ablation. In conclusion, CuO-PLGA-NS constitute a versatile platform, potentially useful for

Quantitative description of proton exchange processes between water and endogenous and exogenous agents for WEX, CEST, and APT experiments.

Science.gov (United States)

Zhou, Jinyuan; Wilson, David A; Sun, Phillip Zhe; Klaus, Judith A; Van Zijl, Peter C M

2004-05-01

The proton exchange processes between water and solutes containing exchangeable protons have recently become of interest for monitoring pH effects, detecting cellular mobile proteins and peptides, and enhancing the detection sensitivity of various low-concentration endogenous and exogenous species. In this work, the analytic expressions for water exchange (WEX) filter spectroscopy, chemical exchange-dependent saturation transfer (CEST), and amide proton transfer (APT) experiments are derived by the use of Bloch equations with exchange terms. The effects of the initial states for the system, the difference between a steady state and a saturation state, and the relative contributions of the forward and backward exchange processes are discussed. The theory, in combination with numerical calculations, provides a useful tool for designing experimental schemes and assessing magnetization transfer (MT) processes between water protons and solvent-exchangeable protons. As an example, the case of endogenous amide proton exchange in the rat brain at 4.7 T is analyzed in detail. Copyright 2004 Wiley-Liss, Inc.

IN VITRO Cr(VI SPECIATION IN SYNTHETIC SALIVA AFTER RELEASING FROM ORTHODONTIC BRACKETS USING SILICA-APTES SEPARATION AND GF AAS DETERMINATION

Directory of Open Access Journals (Sweden)

Maciel S. Luz

Full Text Available A method for Cr(VI speciation in synthetic saliva after releasing from orthodontic brackets, using silica nanoparticles organofunctionalized with (3-aminopropyltriethoxysilane (APTES for Cr(III/Cr(VI separation and GF AAS determination is proposed. Under the optimized conditions, Cr(VI speciation was performed using 150 mg of silica organofunctionalized with 2.0% (v v-1 of APTES at pH 8. It was observed different sensitivity when calibrations of GF AAS were performed using Cr(III or Cr(VI as standard solutions. Consequently, calibrations using stoichiometric mixtures (Cr(III + Cr(VI were used for total Cr determination and calibration using Cr(VI was used only for the determination of this specie. The reliability of the proposed silica-APTES separation procedure and GF AAS determination was checked by addition of both species in synthetic saliva. Recoveries ranging from 97 to 110% were obtained. The repeatability, based on the relative standard deviation (RSD inter days was less than 6%. A corrosion test was carried out on 20 orthodontic brackets from two different models, after immersion in synthetic saliva (pH=6.0 at 37 °C with agitation (125 rpm for 24 h. It was observed that about 40% of the total chromium released from the analyzed orthodontic brackets was Cr(VI.

Enhanced water use efficiency in global terrestrial ecosystems under increasing aerosol loadings

Energy Technology Data Exchange (ETDEWEB)

Lu, Xiaoliang; Chen, Min; Liu, Yaling; Miralles, Diego G.; Wang, Faming

2017-05-01

Aerosols play a crucial role in the climate system, affecting incoming radiation and cloud formation. Based on a modelling framework that couples ecosystem processes with the atmospheric transfer of radiation, we analyze the effect of aerosols on surface incoming radiation, gross primary productivity (GPP), water losses from ecosystems through evapotranspiration (ET) and ecosystem water use efficiency (WUE, defined as GPP/ET) for 2003–2010 and validate them at global FLUXNET sites. The total diffuse radiation increases under relatively low or intermediate aerosol loadings, but decreases under more polluted conditions. We find that aerosol-induced changes in GPP depend on leaf area index, aerosol loading and cloudiness. Specifically, low and moderate aerosol loadings cause increases in GPP for all plant types, while heavy aerosol loadings result in enhancement (decrease) in GPP for dense (sparse) vegetation. On the other hand, ET is mainly negatively affected by aerosol loadings due to the reduction in total incoming radiation. Finally, WUE shows a consistent rise in all plant types under increasing aerosol loadings. Overall, the simulated daily WUE compares well with observations at 43 eddy-covariance tower sites (R²=0.84 and RMSE=0.01gC (kg H₂O)^-1) with better performance at forest sites. In addition to the increasing portions of diffuse light, the rise in WUE is also favored by the reduction in radiation- and heat-stress caused by the aerosols, especially for wet and hot climates.

Facile biosynthesis of Ag-NPs using Otostegia limbata plant extract: Physical characterization and auspicious biological activities

Directory of Open Access Journals (Sweden)

Rizwan Kausar

2016-09-01

Full Text Available Silver nanoparticles (Ag-NPs synthesized through reduction by Otostegia limbata green extract are, hereby, reported for the first time. It is very interesting to observe that in this case, O. limbata plant extract acts as a strong chelating agent in Ag-NPs formation through AgNO3. Scanning electron microscope (SEM studies expose that Ag-NPs formation is highly homogenous and spherical with mean particle size of 32±0.8 nm. A typical Ag absorption peak has been observed at 419 nm by ultra violet (UV-visible spectroscopy which have endorsed the successful formation of single phase Ag-NPs. X-ray diffraction (XRD and Fourier transform infrared spectroscopy (FTIR examination further validates the crystalline pure phase structure of Ag-NPs. Promising results have been recorded against protein kinase inhibition assay and antibacterial assay having prominent pathogenic strains. Our present study explores that biosynthesized eco-friendly Ag-NPs have great potential, in the future, for anticancer drug development with wide range pharmaceutical applications.

Highly sensitive C-reactive protein (CRP) assay using metal-enhanced fluorescence (MEF)

International Nuclear Information System (INIS)

Zhang, Yi; Keegan, Gemma L.; Stranik, Ondrej; Brennan-Fournet, Margaret E.; McDonagh, Colette

2015-01-01

Fluorescence has been extensively employed in the area of diagnostic immunoassays. A significant enhancement of fluorescence can be achieved when noble metal nanoparticles are placed in close proximity to fluorophores. This effect, referred to as metal-enhanced fluorescence (MEF), has the potential to produce immunoassays with a high sensitivity and a low limit of detection (LOD). In this study, we investigate the fluorescence enhancement effect of two different nanoparticle systems, large spherical silver nanoparticles (AgNPs) and gold edge-coated triangular silver nanoplates, and both systems were evaluated for MEF. The extinction properties and electric field enhancement of both systems were modeled, and the optimum system, spherical AgNPs, was used in a sandwich immunoassay for human C-reactive protein with a red fluorescent dye label. A significant enhancement in the fluorescence was observed, which corresponded to an LOD improvement of ∼19-fold compared to a control assay without AgNPs

Highly sensitive C-reactive protein (CRP) assay using metal-enhanced fluorescence (MEF)

Energy Technology Data Exchange (ETDEWEB)

Zhang, Yi; Keegan, Gemma L., E-mail: gemmakeegan@gmail.com [Dublin City University, School of Physical Sciences, Biomedical Diagnostics Institute (Ireland); Stranik, Ondrej [Leibniz Institute of Photonic Technology, Department of NanoBiophotonics (Germany); Brennan-Fournet, Margaret E. [CMP-EMSE, MOC, Department of Bioelectronics, Ecole Nationale Superieure des Mines (France); McDonagh, Colette [Dublin City University, School of Physical Sciences, Biomedical Diagnostics Institute (Ireland)

2015-07-15

Fluorescence has been extensively employed in the area of diagnostic immunoassays. A significant enhancement of fluorescence can be achieved when noble metal nanoparticles are placed in close proximity to fluorophores. This effect, referred to as metal-enhanced fluorescence (MEF), has the potential to produce immunoassays with a high sensitivity and a low limit of detection (LOD). In this study, we investigate the fluorescence enhancement effect of two different nanoparticle systems, large spherical silver nanoparticles (AgNPs) and gold edge-coated triangular silver nanoplates, and both systems were evaluated for MEF. The extinction properties and electric field enhancement of both systems were modeled, and the optimum system, spherical AgNPs, was used in a sandwich immunoassay for human C-reactive protein with a red fluorescent dye label. A significant enhancement in the fluorescence was observed, which corresponded to an LOD improvement of ∼19-fold compared to a control assay without AgNPs.

n vivo retention of ingested Au NPs by Daphnia magna: No evidence for trans-epithelial alimentary uptake

Science.gov (United States)

Khan, Farhan R.; Kennaway, Gabrielle M.; Croteau, Marie-Noële; Dybowska, Agnieszka; Smith, Brian D.; Nogueira, António J.A.; Rainbow, Philip S.; Luoma, Samuel N.; Valsami-Jones, Eugenia

2014-01-01

In vivo studies with Daphnia magna remain inconclusive as to whether engineered nanoparticles (NPs) are internalized into tissues after ingestion. Here we used a three-pronged approach to study the in vivo retention and efflux kinetics of 20 nm citrate stabilized Au NPs ingested by this key aquatic species. Daphnids were exposed to suspended particles (600 μg L−1) for 5 h after which they were depurated for 24 h in clean water containing algae. Light microscopy was used to follow the passage of Au NPs through the gastrointestinal tract, Au body burdens were determined by ICP-MS (inductively coupled plasma mass spectrometry), and transmission electron microscopy (TEM) was used to examine the presence and distribution of Au NPs in tissues. Results revealed that the elimination of Au NPs was bi-phasic. The fast elimination phase lasted −1 (±SE) which accounted for ∼75% of the ingested Au. The remaining ∼25% of the ingested Au NPs was eliminated at a 100-fold slower rate. TEM analysis revealed that Au NPs in the midgut were in close proximity to the peritrophic membrane after 1 and 24 h of depuration. There were no observations of Au NP uptake at the microvilli. Thus, although Au NPs were retained in the gut lumen, there was no observable internalization into the gut epithelial cells. Similar to carbon nanotubes and CuO NPs, our findings indicate that in daphnids the in vivo retention of Au NPs does not necessarily result in their internalization.

Surface bioengineering of diatomite based nanovectors for efficient intracellular uptake and drug delivery

Science.gov (United States)

Terracciano, Monica; Shahbazi, Mohammad-Ali; Correia, Alexandra; Rea, Ilaria; Lamberti, Annalisa; de Stefano, Luca; Santos, Hélder A.

2015-11-01

Diatomite is a natural porous silica material of sedimentary origin. Due to its peculiar properties, it can be considered as a valid surrogate of synthetic porous silica for nano-based drug delivery. In this work, we exploit the potential of diatomite nanoparticles (DNPs) for drug delivery with the aim of developing a successful dual-biofunctionalization method by polyethylene glycol (PEG) coverage and cell-penetrating peptide (CPP) bioconjugation, to improve the physicochemical and biological properties of the particles, to enhance the intracellular uptake in cancer cells, and to increase the biocompatibility of 3-aminopropyltriethoxysilane (APT) modified-DNPs. DNPs-APT-PEG-CPP showed hemocompatibility for up to 200 μg mL-1 after 48 h of incubation with erythrocytes, with a hemolysis value of only 1.3%. The cytotoxicity of the modified-DNPs with a concentration up to 200 μg mL-1 and incubation with MCF-7 and MDA-MB-231 breast cancer cells for 24 h, demonstrated that PEGylation and CPP-bioconjugation can strongly reduce the cytotoxicity of DNPs-APT. The cellular uptake of the modified-DNPs was also evaluated using the above mentioned cancer cell lines, showing that the CPP-bioconjugation can considerably increase the DNP cellular uptake. Moreover, the dual surface modification of DNPs improved both the loading of a poorly water-soluble anticancer drug, sorafenib, with a loading degree up to 22 wt%, and also enhanced the drug release profiles in aqueous solutions. Overall, this work demonstrates that the biofunctionalization of DNPs is a promising platform for drug delivery applications in cancer therapy as a result of its enhanced stability, biocompatibility, cellular uptake, and drug release profiles.Diatomite is a natural porous silica material of sedimentary origin. Due to its peculiar properties, it can be considered as a valid surrogate of synthetic porous silica for nano-based drug delivery. In this work, we exploit the potential of diatomite nanoparticles

Highly sensitive work function hydrogen gas sensor based on PdNPs/SiO2/Si structure at room temperature

Directory of Open Access Journals (Sweden)

G. Behzadi pour

Full Text Available In this study, fabrication of highly sensitive PdNPs/SiO2/Si hydrogen gas sensor using experimental and theoretical methods has been investigated. Using chemical method the PdNPs are synthesized and characterized by X-ray diffraction (XRD. The average size of PdNPs is 11 nm. The thickness of the oxide film was 20 nm and the surface of oxide film analyzed using Atomic-force microscopy (AFM. The C-V curve for the PdNPs/SiO2/Si hydrogen gas sensor in 1% hydrogen concentration and at the room temperature has been reported. The response time and recovery time for 1% hydrogen concentration at room temperature were 1.2 s and 10 s respectively. The response (R% for PdNPs/SiO2/Si MOS capacitor hydrogen sensor was 96%. The PdNPs/SiO2/Si MOS capacitor hydrogen sensor showed very fast response and recovery times compared to SWCNTs/PdNPs, graphene/PdNPs, nanorod/PdNPs and nanowire/PdNPs hydrogen gas sensors. Keywords: Sensitive, Oxide film, Capacitive, Resistance

Aurora kinase inhibitors attached to iron oxide nanoparticles enhances inhibition of the growth of liver cancer cells

Energy Technology Data Exchange (ETDEWEB)

Zhang, Xiquan [Southeast University, State Key Laboratory of Bioelectronics and Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science & Medical Engineering (China); Xie, Li [Southeast University, Zhongda Hospital, School of Medicine (China); Zheng, Ming; Yao, Juan [Jiangsu Chai Tai Tianqing Pharmaceutical Co. Ltd. (China); Song, Lina [Southeast University, State Key Laboratory of Bioelectronics and Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science & Medical Engineering (China); Chang, Weiwei [Jiangsu Chai Tai Tianqing Pharmaceutical Co. Ltd. (China); Zhang, Yu; Ji, Min, E-mail: minji888@hotmail.com; Gu, Ning, E-mail: guning@seu.edu.cn [Southeast University, State Key Laboratory of Bioelectronics and Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science & Medical Engineering (China); Zhan, Xi, E-mail: zhan01@gmail.com [University of Maryland School of Medicine, The Center of Vascular and Inflammatory Diseases, The Department of Pathology (United States)

2015-06-15

We have developed a novel Aurora kinase inhibitor (AKI) AM-005, an analogue of pan-AKI AT-9283. To improve the intracellular efficacy of AM-005 and AT-9283, we utilized magnetite nanoparticles (NPs) to deliver AM-005 and AT-9283 into human SMMC-7721 and HepG2 liver cancer cells. The drug-loaded NPs were prepared through quasi-emulsion solvent diffusion of magnetite NPs with AM-005 or AT-9283. The encapsulated drugs were readily released from NPs, preferentially at low pHs. Upon exposure, cancer cells effectively internalized drug-loaded NPs into lysosome-like vesicles, which triggered a series of cellular changes, including the formation of enlarged cytoplasm, the significant increase of membrane permeability, and the generation of reactive oxygen species (ROS). The increased ROS synthesis sustained over 72 h, whereas that in the cells treated with free-form drugs declined rapidly after 48 h. However, chemical sequestration of the iron core of NPs had a minor influence on the generation of intracellular ROS. On the other hand, uncoupling of AM-005 uptake with NP internalization into cells failed to induce ROS synthesis. Overall, our approach achieved two-fold increase in suppressing the viability of tumor cells in vitro and the growth of tumors in vivo. We conclude that magnetite NPs can be used as pH responsive nanocarriers that are able to improve the efficacy of AKIs.

Transferrin receptor antibody-modified α-cobrotoxin-loaded nanoparticles enable drug delivery across the blood-brain barrier by intranasal administration

Science.gov (United States)

Liu, Lin; Zhang, Xiangyi; Li, Wuchao; Sun, Haozhen; Lou, Yan; Zhang, Xingguo; Li, Fanzhu

2013-11-01

A novel drug carrier for brain delivery, maleimide-poly(ethyleneglycol)-poly(lactide) (maleimide-PEG-PLA) nanoparticles (NPs) conjugated with mouse-anti-rat monoclonal antibody OX26 (OX26-NPs), was developed and its brain delivery property was evaluated. The diblock copolymers of maleimide-PEG-PLA were synthesized and applied to α-cobrotoxin (αCT)-loaded NPs which were characterized by transmission electron micrograph imaging, Fourier-transform IR, and X-ray diffraction. The NPs encapsulating αCT had a round and vesicle-like shape with a mean diameter around 100 nm, and the OX26 had covalently conjugated to the surface of NPs. MTT studies in brain microvascular endothelial cells (BMEC) revealed a moderate decrease in the cell viability of αCT, when incorporated in OX26-NPs compared to free αCT in solution. A higher affinity of the OX26-αCT-NPs to the BMEC was shown in comparison to αCT-NPs. Then, OX26-αCT-NPs were intranasally (i.n.) administered to rats, and αCT in the periaqueductal gray was monitored for up to 480 min using microdialysis technique in free-moving rats, with i.n. αCT-NPs, i.n. OX26-αCT-NPs, intramuscular injection (i.m.) αCT-NPs, and i.m. OX26-αCT-NPs. The brain transport results showed that the corresponding absolute bioavailability ( F abs) of i.n. OX26-αCT-NPs were about 125 and 155 % with i.n. αCT-NPs and i.m. OX26-αCT-NPs, respectively, and it was found that both the C max and AUC of the four groups were as follows: i.n. OX26-αCT-NPs > i.n. αCT-NPs > i.m. OX26-αCT-NPs > i.m. αCT-NPs, while αCT solution, as control groups, could hardly enter the brain. These results indicated that OX26-NPs are promising carriers for peptide brain delivery.

Near-infrared fluorescence imaging platform for quantifying in vivo nanoparticle diffusion from drug loaded implants.

Science.gov (United States)

Markovic, Stacey; Belz, Jodi; Kumar, Rajiv; Cormack, Robert A; Sridhar, Srinivas; Niedre, Mark

2016-01-01

Drug loaded implants are a new, versatile technology platform to deliver a localized payload of drugs for various disease models. One example is the implantable nanoplatform for chemo-radiation therapy where inert brachytherapy spacers are replaced by spacers doped with nanoparticles (NPs) loaded with chemotherapeutics and placed directly at the disease site for long-term localized drug delivery. However, it is difficult to directly validate and optimize the diffusion of these doped NPs in in vivo systems. To better study this drug release and diffusion, we developed a custom macroscopic fluorescence imaging system to visualize and quantify fluorescent NP diffusion from spacers in vivo. To validate the platform, we studied the release of free fluorophores, and 30 nm and 200 nm NPs conjugated with the same fluorophores as a model drug, in agar gel phantoms in vitro and in mice in vivo. Our data verified that the diffusion volume was NP size-dependent in all cases. Our near-infrared imaging system provides a method by which NP diffusion from implantable nanoplatform for chemo-radiation therapy spacers can be systematically optimized (eg, particle size or charge) thereby improving treatment efficacy of the platform.

Horseradish peroxidase-loaded nanospheres attached to hollow gold nanoparticles as signal enhancers in an ultrasensitive immunoassay for alpha-fetoprotein

International Nuclear Information System (INIS)

Li, Ya; Yuan, Ruo; Chai, Yaqin; Zhuo, Ying; Su, Huilan; Zhang, Yuxia

2014-01-01

We report on a novel electrochemical signal amplification strategy for use in immunoassays. The highly responsive immunoelectrode was constructed in the following way: (1) The surface of a gold electrode was covered with a layer single-walled carbon nanotubes dispersed in chitosane functionalized with L-cysteine; (2) Gold nanoparticles containing protein A and anti-alpha-fetoprotein (anti-AFP) were then covalently attached to the surface via the thiol groups of the chitosane. The electrode is then exposed to the analyte (AFP) which then is bound by the antibody. In the next step, a gold-conjugated secondary antibody is added that was prepared in the following way: (1) Horseradish peroxidase was crosslinked and the resulting spheres were coated with hollow gold nanoparticles (hollow Au-NPs) to give nanospheres of ∼100 nm in diameter. (2) These were the coated with thionine and, in a last step, with secondary antibody. The use of these materials has several attractive features: The HRP-NPs functionalized with hollow Au-NPs possess a large surface area that can load the large amount of secondary antibody. Thionine (Thi) is highly redox active and improves the intensity of the signal. Carbon nanotubes were used because they possess an excellent electron transfer rate and large surface area. Following incubation of the modified electrode (a) with a sample containing AFP, (b) then with the secondary antibody, and (c) with washing buffer, the electrode is placed in a solution containing H 2 O 2 . The HRP in the smart secondary antibody causes the catalytic decomposition of H 2 O 2 and the results in an electrical current that is linearly related to the concentration of AFP in the 0.025 to 5.0 ng mL −1 concentration range. The detection limit for AFP is as low as 8.3 pg mL −1 . We believe that this novel kind of immunoassay represents a promising tool for use in sensitive clinical assays. (author)

APT LLRF control system functionality and architecture

International Nuclear Information System (INIS)

Regan, A.H.; Rohlev, A.S.; Ziomek, C.D.

1996-01-01

1% amplitude and l degree phase. The feedback control system requires a phase-stable RF reference subsystem signal to correctly phase each cavity. Also, instead of a single klystron RF source for individual accelerating cavities, multiple klystrons will drive a string of resonantly coupled cavities, based on input from a single LLRF feedback control system. To achieve maximum source efficiency, we will be employing single fast feedback controls around individual klystrons such that the gain and phase characteristics of each will be ''identical.'' In addition, resonance control is performed by providing a proper drive signal to structure cooling water valves in order to keep the cavity resonant during operation. To quickly respond to RF shutdowns, and hence rapid accelerating cavity cool- down, due to RF fault conditions, drive frequency agility in the main feedback control subsystem will also be incorporated. Top level block diagrams will be presented and described for each of the aforementioned subsystems as they will first be developed and demonstrated on the Low Energy Demonstrator Accelerator (LEDA) The low-level RF (LLRF) control system for the Accelerator Production of Tritium (APT) will perform various functions. Foremost is the feedback control of the accelerating fields within the cavity in order to maintain field stability within

The RF system for the Accelerator Production of Tritium (APT) Low Energy Demonstration Accelerator (LEDA) at Los Alamos

International Nuclear Information System (INIS)

Lynch, M.T.; Rees, D.; Tallerico, P.; Regan, A.

1996-01-01

To develop and demonstrate the crucial front end of the APT accelerator and some of the critical components for APT, Los Alamos is building a CW proton accelerator (LEDA) to provide 100 mA at up to 40 MeV. LEDA will be installed where the SDI-sponsored Ground Test Accelerator was located. The first accelerating structure for LEDA is a 7-MeV RFQ operating at 350 MHz, followed by several stages of a coupled-cavity Drift Tube Linac (CCDTL) operating at 700 MHz. The first stage of LEDA will go to 12 MeV. Higher energies, up to 40 MeV, come later in the program. Three 1.2-MW CW RF systems will be used to power the RFQ. This paper describes the RF systems being assembled for LEDA, including the 350 and 700-MHz klystrons, the High Voltage Power Supplies, transmitters, RF transport, window/coupler assemblies, and controls. Some of the limitations imposed by the schedule and the building itself are addressed

Colorimetric detection with aptamer-gold nanoparticle conjugates coupled to an android-based color analysis application for use in the field.

Science.gov (United States)

Smith, Joshua E; Griffin, Daniel K; Leny, Juliann K; Hagen, Joshua A; Chávez, Jorge L; Kelley-Loughnane, Nancy

2014-04-01

The feasibility of using aptamer-gold nanoparticle conjugates (Apt-AuNPs) to design colorimetric assays for in the field detection of small molecules was investigated. An assay to detect cocaine was designed using two clones of a known cocaine-binding aptamer. The assay was based on the AuNPs difference in affinity for single-stranded DNA (non-binding) and double stranded DNA (target bound). In the first assay, a commonly used design was followed, in which the aptamer and target were incubated to allow binding followed by exposure to the AuNPs. Interactions between the non-bound analytes and the AuNPs surface resulted in a number of false positives. The assay was redesigned by incubating the AuNPs and the aptamer prior to target addition to passivate the AuNPs surface. The adsorbed aptamer was able to bind the target while preventing non-specific interactions. The assay was validated with a number of masking and cutting agents and other controlled substances showing minimal false positives. Studies to improve the assay performance in the field were performed, showing that assay activity could be preserved for up to 2 months. To facilitate the assay analysis, an android application for automatic colorimetric characterization was developed. The application was validated by challenging the assay with cocaine standards of different concentrations, and comparing the results to a conventional plate reader, showing outstanding agreement. Finally, the rapid identification of cocaine in mixtures mimicking street samples was demonstrated. This work established that Apt-AuNPs can be used to design robust assays to be used in the field. Copyright © 2013 Elsevier B.V. All rights reserved.

NPS-SCAT: Systems Engineering and Payload Subsystem Design, Integration, and Testing of NPS’ First CubeSat

Science.gov (United States)

2010-06-01

uses the photovoltaic (PV) effect to produce electrical power . Discovered in 1839, the PV effect “is the direct conversion of light into electricity...electrical power subsystem (EPS) of the NPS-SCAT satellite is used to provide, store, distribute, and control the spacecraft electrical power [52]. The...current not to exceed 0.5 A; the solar panels must be designed to meet this specification. The BCRs use a maximum power point tracker ( MPPT ) to

Complete Au@ZnO core-shell nanoparticles with enhanced plasmonic absorption enabling significantly improved photocatalysis

Science.gov (United States)

Sun, Yiqiang; Sun, Yugang; Zhang, Tao; Chen, Guozhu; Zhang, Fengshou; Liu, Dilong; Cai, Weiping; Li, Yue; Yang, Xianfeng; Li, Cuncheng

2016-05-01

Nanostructured ZnO exhibits high chemical stability and unique optical properties, representing a promising candidate among photocatalysts in the field of environmental remediation and solar energy conversion. However, ZnO only absorbs the UV light, which accounts for less than 5% of total solar irradiation, significantly limiting its applications. In this article, we report a facile and efficient approach to overcome the poor wettability between ZnO and Au by carefully modulating the surface charge density on Au nanoparticles (NPs), enabling rapid synthesis of Au@ZnO core-shell NPs at room temperature. The resulting Au@ZnO core-shell NPs exhibit a significantly enhanced plasmonic absorption in the visible range due to the Au NP cores. They also show a significantly improved photocatalytic performance in comparison with their single-component counterparts, i.e., the Au NPs and ZnO NPs. Moreover, the high catalytic activity of the as-synthesized Au@ZnO core-shell NPs can be maintained even after many cycles of photocatalytic reaction. Our results shed light on the fact that the Au@ZnO core-shell NPs represent a promising class of candidates for applications in plasmonics, surface-enhanced spectroscopy, light harvest devices, solar energy conversion, and degradation of organic pollutants.Nanostructured ZnO exhibits high chemical stability and unique optical properties, representing a promising candidate among photocatalysts in the field of environmental remediation and solar energy conversion. However, ZnO only absorbs the UV light, which accounts for less than 5% of total solar irradiation, significantly limiting its applications. In this article, we report a facile and efficient approach to overcome the poor wettability between ZnO and Au by carefully modulating the surface charge density on Au nanoparticles (NPs), enabling rapid synthesis of Au@ZnO core-shell NPs at room temperature. The resulting Au@ZnO core-shell NPs exhibit a significantly enhanced plasmonic

Preparation and characterization of AuNPs/CNTs-ErGO electrochemical sensors for highly sensitive detection of hydrazine.

Science.gov (United States)

Zhao, Zhenting; Sun, Yongjiao; Li, Pengwei; Zhang, Wendong; Lian, Kun; Hu, Jie; Chen, Yong

2016-09-01

A highly sensitive electrochemical sensor of hydrazine has been fabricated by Au nanoparticles (AuNPs) coating of carbon nanotubes-electrochemical reduced graphene oxide composite film (CNTs-ErGO) on glassy carbon electrode (GCE). Cyclic voltammetry and potential amperometry have been used to investigate the electrochemical properties of the fabricated sensors for hydrazine detection. The performances of the sensors were optimized by varying the CNTs to ErGO ratio and the quantity of Au nanoparticles. The results show that under optimal conditions, a sensitivity of 9.73μAμM(-1)cm(-2), a short response time of 3s, and a low detection limit of 0.065μM could be achieved with a linear concentration response range from 0.3μM to 319μM. The enhanced electrochemical performances could be attributed to the synergistic effect between AuNPs and CNTs-ErGO film and the outstanding catalytic effect of the Au nanoparticles. Finally, the sensor was successfully used to analyse the tap water, showing high potential for practical applications. Copyright © 2016 Elsevier B.V. All rights reserved.

Polycaprolactone Based Nanoparticles Loaded with Indomethacin for Anti-Inflammatory Therapy: From Preparation to Ex Vivo Study.

Science.gov (United States)

Badri, Waisudin; Miladi, Karim; Robin, Sophie; Viennet, Céline; Nazari, Qand Agha; Agusti, Géraldine; Fessi, Hatem; Elaissari, Abdelhamid

2017-09-01

This work focused on the preparation of polycaprolactone based nanoparticles containing indomethacin to provide topical analgesic and anti-inflammatory effect for symptomatic treatment of inflammatory diseases. Indomethacin loaded nanoparticles are prepared for topical application to decrease indomethacin side effects and administration frequency. Oppositely to already reported works, in this research non-invasive method has been used for the enhancement of indomethacin dermal drug penetration. Ex-vivo skin penetration study was carried out on fresh human skin. Nanoprecipitation was used to prepare nanoparticles. Nanoparticles were characterized using numerous techniques; dynamic light scattering, SEM, TEM, DSC and FTIR. Regarding ex-vivo skin penetration of nanoparticles, confocal laser scanning microscopy has been used. The results showed that NPs hydrodynamic size was between 220 to 245 nm and the zeta potential value ranges from -19 to -13 mV at pH 5 and 1 mM NaCl. The encapsulation efficiency was around 70% and the drug loading was about 14 to 17%. SEM and TEM images confirmed that the obtained nanoparticles were spherical with smooth surface. The prepared nanoparticles dispersions were stable for a period of 30 days under three temperatures of 4°C, 25°C and 40°C. In addition, CLSM images proved that obtained NPs can penetrate the skin as well. The prepared nanoparticles are submicron in nature, with good colloidal stability and penetrate the stratum corneum layer of the skin. This formulation potentiates IND skin penetration and as a promising strategy would be able to decline the side effects of IND.

Influence of picosecond multiple/single line ablation on copper nanoparticles fabricated for surface enhanced Raman spectroscopy and photonics applications

International Nuclear Information System (INIS)

Hamad, Syed; Tewari, Surya P; Podagatlapalli, G Krishna; Rao, S Venugopal

2013-01-01

A comprehensive study comprising fabrication of copper nanoparticles (NPs) using picosecond (ps) multiple/single line ablation in various solvents such as acetone, dichloromethane (DCM), acetonitrile (ACN) and chloroform followed by optical, nonlinear optical (NLO), and surface enhanced Raman spectroscopy (SERS) characterization was performed. The influence of surrounding liquid media and the writing conditions resulted in fabrication of Cu NPs in acetone, CuCl NPs in DCM, CuO NPs in ACN and CuCl 2 NPs in chloroform. Prepared colloids were characterized through transmission electron microscopy, energy dispersive x-ray spectra, selected area electron diffraction and UV-visible absorption spectra. A detailed investigation of the surface enhanced Raman scattering (SERS) activity and the ps NLO properties of the colloids prepared through multiple/single line ablation techniques revealed that the best performance was achieved by Cu NPs for SERS applications and CuCl 2 NPs for NLO applications. (paper)

Epidermal Growth Factor Enhances Cellular Uptake of Polystyrene Nanoparticles by Clathrin-Mediated Endocytosis.

Science.gov (United States)

Phuc, Le Thi Minh; Taniguchi, Akiyoshi

2017-06-19

The interaction between nanoparticles and cells has been studied extensively, but most research has focused on the effect of various nanoparticle characteristics, such as size, morphology, and surface charge, on the cellular uptake of nanoparticles. In contrast, there have been very few studies to assess the influence of cellular factors, such as growth factor responses, on the cellular uptake efficiency of nanoparticles. The aim of this study was to clarify the effects of epidermal growth factor (EGF) on the uptake efficiency of polystyrene nanoparticles (PS NPs) by A431 cells, a human carcinoma epithelial cell line. The results showed that EGF enhanced the uptake efficiency of A431 cells for PS NPs. In addition, inhibition and localization studies of PS NPs and EGF receptors (EGFRs) indicated that cellular uptake of PS NPs is related to the binding of EGF-EGFR complex and PS NPs. Different pathways are used to enter the cells depending on the presence or absence of EGF. In the presence of EGF, cellular uptake of PS NPs is via clathrin-mediated endocytosis, whereas, in the absence of EGF, uptake of PS NPs does not involve clathrin-mediated endocytosis. Our findings indicate that EGF enhances cellular uptake of PS NPs by clathrin-mediated endocytosis. This result could be important for developing safe nanoparticles and their safe use in medical applications.

Epidermal Growth Factor Enhances Cellular Uptake of Polystyrene Nanoparticles by Clathrin-Mediated Endocytosis

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Le Thi Minh Phuc

2017-06-01

Full Text Available The interaction between nanoparticles and cells has been studied extensively, but most research has focused on the effect of various nanoparticle characteristics, such as size, morphology, and surface charge, on the cellular uptake of nanoparticles. In contrast, there have been very few studies to assess the influence of cellular factors, such as growth factor responses, on the cellular uptake efficiency of nanoparticles. The aim of this study was to clarify the effects of epidermal growth factor (EGF on the uptake efficiency of polystyrene nanoparticles (PS NPs by A431 cells, a human carcinoma epithelial cell line. The results showed that EGF enhanced the uptake efficiency of A431 cells for PS NPs. In addition, inhibition and localization studies of PS NPs and EGF receptors (EGFRs indicated that cellular uptake of PS NPs is related to the binding of EGF–EGFR complex and PS NPs. Different pathways are used to enter the cells depending on the presence or absence of EGF. In the presence of EGF, cellular uptake of PS NPs is via clathrin-mediated endocytosis, whereas, in the absence of EGF, uptake of PS NPs does not involve clathrin-mediated endocytosis. Our findings indicate that EGF enhances cellular uptake of PS NPs by clathrin-mediated endocytosis. This result could be important for developing safe nanoparticles and their safe use in medical applications.

Preparation and in vitro characterization of 9-nitrocamptothecin-loaded long circulating nanoparticles for delivery in cancer patients

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Katayoun Derakhshandeh

2010-07-01

Full Text Available Katayoun Derakhshandeh1, Marzieh Soheili1, Simin Dadashzadeh2, Reza Saghiri31Department of Pharmaceutics, Faculty of Pharmacy, University of Medical Science, Kermanshah 67145-1673, Iran; 2Department of Pharmaceutics, Faculty of Pharmacy, Shaheed Beheshti University of Medical Science, Tehran, Iran; 3Deptartment of Biochemistry, Pasteur Institute, Tehran, IranAbstract: The purpose in this study was to investigate poly(ethylene glycol-modified poly (d,l-lactide-co-glycolide nanoparticles (PLGA-PEG-NPs loading 9-nitrocamptothecin (9-NC as a potent anticancer drug. 9-NC is an analog of the natural plant alkaloid camptothecin that has shown high antitumor activity and is currently in the end stage of clinical trial. Unfortunately, at physiological pH, these potent agents undergo a rapid and reversible hydrolysis with the loss of antitumor activity. Previous researchers have shown that the encapsulation of this drug in PLGA nanoparticles could increase its stability and release profile. In this research we investigated PLGA-PEG nanoparticles and their effect on in vitro characteristics of this labile drug. 9-NC-PLGA-PEG nanoparticles with particle size within the range of 148.5 ± 30 nm were prepared by a nanoprecipitation method. The influence of four different independent variables (amount of polymer, percent of emulsifier, internal phase volume, and external phase volume on nanoparticle drug-loading was studied. Differential scanning calorimetry and X-ray diffractometry were also evaluated for physical characterizing. The results of optimized formulation showed a narrow size distribution, suitable zeta potential (+1.84, and a drug loading of more than 45%. The in vitro drug release from PLGA-PEG NPs showed a sustained release pattern of up to 120 hours and comparing with PLGA-NPs had a significant decrease in initial burst effect. These experimental results indicate that PLGA-PEG-NPs (versus PLGA-NPs have a better physicochemical characterization

Enhanced optical output of InGaN/GaN near-ultraviolet light-emitting diodes by localized surface plasmon of colloidal silver nanoparticles

International Nuclear Information System (INIS)

Hong, Sang-Hyun; Kim, Jae-Joon; Jung, Yen-Sook; Kim, Dong-Yu; Park, Seong-Ju; Kang, Jang-Won; Yim, Sang-Youp

2015-01-01

We report on the characteristics of localized surface plasmon (LSP)-enhanced near-ultraviolet light-emitting diodes (NUV-LEDs) fabricated by using colloidal silver (Ag) nanoparticles (NPs). Colloidal Ag NPs were deposited on the 20 nm thick p-GaN spacer layer using a spray process. The optical output power of NUV-LEDs with colloidal Ag NPs was increased by 48.7% at 20 mA compared with NUV-LEDs without colloidal Ag NPs. The enhancement was attributed to increased internal quantum efficiency caused by the resonance coupling between excitons in the multiple quantum wells and the LSPs in the Ag NPs. (paper)

Green synthesis of Pd NPs from Pimpinella tirupatiensis plant extract and their application in photocatalytic activity dye degradation

Science.gov (United States)

Narasaiah, Palajonna; Mandal, Badal Kumar; Sarada, N. C.

2017-11-01

The present report the synthesis of palladium nanoparticles through the green method route offers few advantages over the common chemical and physical procedures, as it is an easy and fast, eco-friendly and does not involve any costly chemicals as well as hazardous chemicals. In this study, we reported synthesis of Pd NPs by using the Pimpinella tirupatiensis plant Extract (PTPE). The synthesized Pd NPs was characterization using different technique such as UV-Visible for the formation of Pd NPs. FT-IR spectroscopy was performed to detect the bio-active molecules liable for reduction and capping of biogenic Pd NPs. Crystallinity of Pd NPs conformed by powder - XRD. In the present study performed photo catalytic activity of synthesized Pd NPs using organic dye such as Congo red (CR). Hence, this study concludes the PTPE aqueous extract produced Pd NPs can be act as promising material for the degradation of organic pollutants.

The APT program plan: Providing an assured tritium production capability

International Nuclear Information System (INIS)

Lisowski, P.W.; Anderson, J.L.; Bishop, W.P.; Boggs, B.; Hall, K.

1996-01-01

Tritium is a radioactive hydrogen isotope used in all U.S. nuclear weapons. Because the half-life of tritium is short, 12.3 yr, it must be periodically replenished. To provide a new source, the U.S. Department of Energy (DOE) is sponsoring conceptual design and engineering development and demonstration activities for a plant that will use a high-power proton linear accelerator to produce tritium and will go on-line no later than 2007. The APT project is in the process of completing the conceptual design for a tritium production plant. In addition, there are several important areas under engineering development and demonstration that will ensure an efficient, cost-effective plant design and provide an adequate margin of tritium production. Information provided from this work will be used by the DOE in its 1998 choice of production technology implementation

AuNPs Hybrid Black ZnO Nanorods Made by a Sol-Gel Method for Highly Sensitive Humidity Sensing

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Hongyan Zhang

2018-01-01

Full Text Available A highly sensitive self-powered humidity sensor has been realized from AuNPs hybrid black zinc oxide (ZnO nanorods prepared through a sol-gel method. XRD pattern reveals that both ZnO and ZnO/AuNPs exhibit a wurtzite structure. ZnO/AuNPs nanorods grow in a vertical alignment, which possesses high uniformity and forms dense arrays with a smaller diameter than that of ZnO nanoparticles. All ZnO/AuNPs and pure black ZnO show lower band gap energy than the typically reported 3.34 eV of pure ZnO. Furthermore, the band gap of ZnO/AuNPs nanocomposites is effectively influenced by the amount of AuNPs. The humidity sensing tests clearly prove that all the ZnO/AuNPs humidity sensors exhibit much higher response than that of ZnO sensors, and the sensitivity of such ZnO/AuNPs nanorods (6 mL AuNPs display a change three orders higher than that of pure ZnO with relative humidity (RH ranging from 11% to 95% at room temperature. The response and recovery time of the ZnO/AuNPs are 5.6 s and 32.4 s, respectively. This study of the construction of semiconductor/noble metal sensors provides a rational way to control the morphology of semiconductor nanomaterials and to design a humidity sensor with high performance.

LCF data for aging of Cu NPs in soil

Data.gov (United States)

U.S. Environmental Protection Agency — Linear combination fitting data for Cu NPs in five soils as a function of aging time. This dataset is associated with the following publication: Sekine, R., E....

Radiative transition, local field enhancement and energy transfer microcosmic mechanism of tellurite glasses containing Er3+, Yb3+ ions and Ag nanoparticles