WorldWideScience

Sample records for lipid submicron particles

  1. Water condensation for submicronic particles abatement

    OpenAIRE

    Cozzolino, Gennaro

    2013-01-01

    Control of particulate matter (PM) emissions from industrial processes is important for protection of human health and the environment. A promising technique for submicron PM abatement is by condensing water vapor onto the particles, which enhances particle growth and improves the performance of traditional particle collection devices. This thesis analyzes the flue gases cleaning process by means of activation heterogeneous water nucleation mechanism on particles surface as a function of work...

  2. On the dry deposition of submicron particles

    Energy Technology Data Exchange (ETDEWEB)

    Wesely, M. L.

    1999-10-08

    The air-surface exchange of particles can have a strong role in determining the amount, size, and chemical composition of particles in the troposphere. Here the authors consider only dry processes (deposition processes not directly aided by precipitation) and mostly address particles less than about 2 {micro}m in diameter (often referred to as submicron particles because most of such particles are less than 1 {micro}m in diameter). The processes that control the dry exchange of particulate material between the atmosphere and the surface of the Earth are numerous, highly varied, and sometimes poorly understood. As a result, determining which of the surface processes to parameterize or simulate in modeling the tropospheric mass budget of a particulate substance can be a significant challenge. Dry deposition, for example, can be controlled by a combination of Brownian diffusion, impaction, interception, and gravitational settling, depending on the size of the particles, the roughness of the surface on both micrometeorological and microscopic scales, the geometrical structure of vegetative canopies, and other surface characteristics such as wetness. Particles can be added to the lower atmosphere by resuspension from land surfaces and sea spray. The roles of rapid gas-to-particle conversion and growth or shrinkage of particles as a result of water condensation or evaporation in the lower few meters of the atmosphere can also have a significant impact on particle concentrations in the lower atmosphere. Here, a few micrometeorological observations and inferences on particle air-surface exchange are briefly addressed.

  3. Submicron R2Fe14B particles

    Directory of Open Access Journals (Sweden)

    O. Koylu-Alkan

    2016-05-01

    Full Text Available Mechanochemical synthesis of submicron R2Fe14B particles with R = Dy, Nd, Pr has been performed successfully via high energy ball milling of rare-earth oxides, iron oxide and boron oxide in the presence of a reducing agent (Ca and a dispersant material (CaO, followed by annealing at 800 - 900 °C. In the R = Nd system, we were able to fabricate particles embedded in a CaO matrix with coercivity (Hc of 10.3 kOe after annealing at 900 °C for 5 min. After washing off the dispersant, the Hc was decreased to below 1 kOe because of hydrogen absorption that leads to the formation of the hydrated R2Fe14BHx phase that has a lower anisotropy. Upon removal of the hydrogen the coercivity was increased to 3.3 kOe. The average size of the Nd2Fe14B particles increases from 100 nm in a sample synthesized at 800 °C to 158 nm at 900 °C. The isotropic Dy2Fe14B particles showed a higher coercivity of 21 kOe in washed samples after annealing at 900 °C for 5 min. An average size of 71 nm is measured in samples synthesized at 800 °C and 107 nm at 900 °C. Fitting the high field M(H measurements in Nd2Fe14B to the law of approach to saturation gave values for the magnetocrystalline anisotropy for the washed sample 2.23 × 107 erg/cm3 and for the vacuum annealed sample 4.15 × 107 erg/cm3, both of which are lower than the bulk values. This would explain the lower values of Hc observed in the particles.

  4. UV Light–Induced Aggregation of Titania Submicron Particles

    Directory of Open Access Journals (Sweden)

    Can Zhou

    2016-11-01

    Full Text Available In this study, aggregation of TiO2 (rutile and anatase submicron particles in deionized (DI water under ultra-violet (UV light irradiation was investigated. While no aggregation was observed in the dark, rutile and anatase submicron particles started aggregating upon application of UV light and ceased aggregation in about 2 and 8.4 h, respectively. It has been demonstrated that UV light directly mitigated the particle mobility of TiO2, resulting in a neutralization effect of the Zeta potential. It was also observed that rutile particles aggregated much faster than anatase particles under UV radiation, indicating that the Zeta potential of as-prepared rutile is less than that of anatase in deionized (DI water. In addition, the interaction energy of rutile and anatase particles was simulated using the Derjaguin–Landau–Verwey–Overbeek (DLVO model. The results showed a significant reduction of barrier energy from 118.2 kBT to 33.6 kBT for rutile and from 333.5 kBT to 46.1 kBT for anatase, respectively, which further validated the remarkable influence of UV irradiation on the aggregation kinetics of rutile and anatase submicron particles. This work presents a further understanding of the aggregation mechanism of light-controlled submicron particles and has a promising potential application in environmental remediation.

  5. Formation of Submicron Copper Sulfide Particles Using Spray Pyrolysis Method

    Science.gov (United States)

    Lenggoro, I.; Kang, Yun; Komiya, Takafumi; Okuyama, Kikuo; Tohge, Noboru

    1998-03-01

    The morphology and crystalline phase of submicron copper sulfide particles prepared by spray pyrolysis method have been studied. In a nitrogen gas atmosphere, the covellite phase (CuS) spherical particles could be prepared using the solution with molar ratio of copper nitrate to thiourea and furnace temperatures of 1:2 at 200 300°C, as well as of 1:5 at 200 600°C. The crystalline phase of particles was highly depended on the composition of the precursors and the pyrolysis temperature. The sphericity of particles could be enhanced by increasing the temperature and prolonging the residence time of the droplets or particles in the furnace.

  6. Silicon in submicron particles in the southwest

    Science.gov (United States)

    Pitchford, Marc; Flocchini, Robert G.; Draftz, Ronald G.; Cahill, Thomas A.; Ashbaugh, Lowell L.; Eldred, Robert A.

    Silicon in the fine particle size range (less than about 2 μm) was investigated. Elemental and microscopical analysis of size segregated, ambient particulate and suspended soil samples from the rural southwest indicate that the particles are earth crust material. The composition of the soil related materials changes with changing particle size. Smaller particles tend to vary more in their elemental makeup than corresponding large particles. Numerous thin mineral plates with diameters of several micrometers are aerodynamically sized in the smallest sample size range (< 0.5 μm). Since silicon accounts for one-quarter to one-half the total mass in the fine particle size range, it may be a significant causal factor in regional visibility degradation.

  7. Lipid nano/submicron emulsions as vehicles for topical flurbiprofen delivery.

    Science.gov (United States)

    Fang, Jia-You; Leu, Yann-Lii; Chang, Chia-Chun; Lin, Chia-Hsuan; Tsai, Yi-Hung

    2004-01-01

    The application of lipid nano/submicron emulsions as topical drug carrier systems for the percutaneous absorption of flurbiprofen was investigated. The lipid emulsions were made up of isopropyl myristate (IPM), soybean oil, or coconut oil as the oil phase, egg lecithin as the predominant emulsifier, and double-distilled water as the external phase. Stearylamine (SA) and deoxycholic acid (DA) also were used to produce positively and negatively charged emulsions. To evaluate the physicochemical properties of the lipid emulsions, particle size by laser light scattering, the image of atomic force microscopy, and relaxation time values by Nuclear Magnetic Resonance (NMR) were determined. The in vitro permeation data showed that incorporation of SA significantly reduced the topical delivery of flurbiprofen. On the other hand, incorporation of DA exhibited no or a negligible effect on drug permeation. Enhancement of drug absorption was observed when adding oleic acid as part of the oil phase. The in vivo topical application of flurbiprofen from selected lipid emulsions showed a similar trend to the in vitro status. Furthermore, the intersubject variability was considerably reduced by lipid emulsions than by aqueous suspensions in both the in vitro and in vivo experiments. The irritant profiles of lipid emulsions showed that IPM elicited higher irritation than soybean oil. The incorporation of oleic acid also produced skin disruption. The results in the present study suggest the feasibility of lipid emulsions for the topical delivery of flurbiprofen.

  8. Submicron particles of Co, Ni and Co–Ni alloys

    Indian Academy of Sciences (India)

    P Saravanan; T A Jose; P John Thomas; G U Kulkarni

    2001-10-01

    Magnetic sub-micron sized particles (with diameters in the range 100–600 nm) of Co, Ni and Co–Ni alloys, protected with polyvinylpyrrolidone have been prepared in gram quantities using the polyol process. Experiments carried out with different metal precursors and starting compositions have yielded reliable routes to produce particles of the desired diameters in the 100–600 nm range. The particles were characterized with X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis, thermogravimetric analysis and magnetic measurements. The particles are found to be stable under ambient conditions indefinitely. The coercivity values of the Co and Ni particles are ∼ 50% higher compared to the corresponding bulk values. The alloy particles follow a trend similar to the bulk alloys.

  9. Submicron particle monitoring of paving and related road construction operations.

    Science.gov (United States)

    Freund, Alice; Zuckerman, Norman; Baum, Lisa; Milek, Debra

    2012-01-01

    This study identified activities and sources that contribute to ultrafine and other submicron particle exposure that could trigger respiratory symptoms in highway repair workers. Submicron particle monitoring was conducted for paving, milling, and pothole repair operations in a major metropolitan area where several highway repair workers were identified as symptomatic for respiratory illness following exposures at the 2001 World Trade Center disaster site. Exposure assessments were conducted for eight trades involved in road construction using a TSI P-Trak portable condensation particle counter. Direct readings near the workers' breathing zones and observations of activities and potential sources were logged on 7 days on 27 workers using four different models of pavers and two types of millers. Average worker exposure levels ranged from 2 to 3 times background during paving and from 1 to 4 times background during milling. During asphalt paving, average personal exposures to submicron particulates were 25,000-60,000, 28,000-70,000, and 23,000-37,000 particles/ cm(3) for paver operators, screed operators, and rakers, respectively. Average personal exposures during milling were 19,000-111,000, 28,000-81,000, and 19,000 particles/cm(3) for the large miller operators, miller screed operators, and raker, respectively. Personal peak exposures were measured up to 467,000 and 455,000 particles/cm(3) in paving and milling, respectively. Several sources of submicron particles were identified. These included the diesel and electric fired screed heaters; engine exhaust from diesel powered construction vehicles passing by or idling; raking, dumping, and paving of asphalt; exhaust from the hotbox heater; pavement dust or fumes from milling operations, especially when the large miller started and stopped; and secondhand cigarette smoke. To reduce the potential for health effects in workers, over 40 recommendations were made to control exposures, including improved maintenance of

  10. Short range investigation of sub-micron zirconia particles

    Energy Technology Data Exchange (ETDEWEB)

    Caracoche, M C; Martinez, J A [Departamento de Fisica, IFLP, Facultad de Ciencias Exactas, CICPBA, Universidad Nacional de La Plata (Argentina); Rivas, P C [IFLP-CONICET, Facultad de Ciencias Agrarias y Forestales, Universidad Nacional de La Plata (Argentina); Bondioli, F; Cannillo, V [Dipartimento di Ingegniria dei Materiali e dell' Ambiente, Facolta di Ingegneria, Universita di Modena e Reggio Emilia (Italy); Ferrari, A M, E-mail: cristina@fisica.unlp.edu.a [Dipartimento di Scienza a Metodi dell' Ingegneria, Universita di Modena e Reggio Emilia (Italy)

    2009-05-01

    The Perturbed Angular Correlations technique was used to determine the configurations around Zirconium ions and their thermal behavior in non-aggregated sub-micron zirconia spherical particles. Three residues containing- Zr surroundings were determined for the non-crystalline starting particles, which were identified under the assumption of a certain chemical reactions sequence during synthesis. While the one made up mainly by hydroxyl groups was common to both samples, the two involving mainly organic residues were particle size dependent. Upon crystallization, both samples stabilized in the t'- and t- tetragonal forms and the Xc-cubic form but their amounts and temperatures of appearance were different. On heating, the structure of the smaller particles became gradually monoclinic achieving total degradation upon the subsequent cooling to RT.

  11. Thermophoretic capture of submicron particles by a droplet

    Science.gov (United States)

    Wang, Ao; Song, Qiang; Yao, Qiang

    2016-12-01

    Thermophoresis is an important mechanism for submicron particle capture by droplets. The thermophoretic deposition efficiencies under varying Reynolds (Re) numbers and temperature differences are obtained from the direct numerical simulation of the submicron particle flowing around the droplet. Comparison of the results calculated under the same conditions through the classical thermophoretic deposition efficiency formula and by numerical simulation shows that the Davenport formula always returns greater values than the numerical simulation, by a relative deviation of 19.8%-63.8%. The relative deviation decreased first and then increased with increasing difference in temperature, and increased gradually with increasing Re. The deviation resulted from the assumption that the particle concentration on the droplet surface is equal to that of the incoming flow in the formula deduction process. The convection of the gas and the thermophoresis of the particles together determined the migration of the particles in the boundary layer, and so determined the particle concentration distribution on the surface of droplets. Thus, the particle concentrations on the surface of droplets are actually lower than those of the incoming flow and are distributed bimodally on the surface. The dimensionless particle concentration on the surface of droplets decreased with increasing Re, and increased first then decreased later with increasing difference in temperature. The dimensionless thermophoretic driving velocity and Re were adopted to correct the formula. The results calculated by the corrected formula were consistent with the numerical simulation employed in this paper, such that the maximum relative deviation was reduced from the original 66.8% to less than 8%.

  12. Tracking Submicron Particles in Microchannel Flow by Microscopic Holography

    Institute of Scientific and Technical Information of China (English)

    罗锐; 刘石

    2012-01-01

    Three-dimensional tracking of submicron particles in flows in a micro-channel was carried out using in-line holographic microscopy.A fixed single 0.5 μm fluorescent particle was identified and isolated from dust particles or overlapped particle pair using the laser induced fluorescent(LIF) method.Then in-line microscopic holograms of the fixed single particle were obtained at different positions on the optical axis,i.e.the defocus distances.The holograms of the single particle were used as the model templates with the known defocus distances.The particles in the in-line microscopic holograms of flow in the microchannel were then identified and located to obtain their two-dimensional positions.The defocus distances of those particles were determined by matching each hologram pattern to one of the model templates obtained in the single particle test.Finally the three-dimensional position and velocity of each particle were obtained.

  13. Discovering sub-micron ice particles across Dione' surface

    Science.gov (United States)

    Scipioni, Francesca; Schenk, Pual; Tosi, Federico; Clark, Roger; Dalle Ore, Cristina; Combe, Jean-Philippe

    2015-11-01

    Water ice is the most abundant component of Saturn’s mid-sized moons. However, these moons show an albedo asymmetry - their leading sides are bright while their trailing side exhibits dark terrains. Such differences arise from two surface alteration processes: (i) the bombardment of charged particles from the interplanetary medium and driven by Saturn’s magnetosphere on the trailing side, and (ii) the impact of E-ring water ice particles on the satellites’ leading side. As a result, the trailing hemisphere appears to be darker than the leading side. This effect is particularly evident on Dione's surface. A consequence of these surface alteration processes is the formation or the implantation of sub-micron sized ice particles.The presence of such particles influences and modifies the surfaces' spectrum because of Rayleigh scattering by the particles. In the near infrared range of the spectrum, the main sub-micron ice grains spectral indicators are: (i) asymmetry and (ii) long ward minimum shift of the absorption band at 2.02 μm (iii) a decrease in the ratio between the band depths at 1.50 and 2.02 μm (iv) a decrease in the height of the spectral peak at 2.6 μm (v) the suppression of the Fresnel reflection peak at 3.1 μm and (vi) the decrease of the reflection peak at 5 μm relative to those at 3.6 μm.We present results from our ongoing work mapping the variation of sub-micron ice grains spectral indicators across Dione' surface using Cassini-VIMS cubes acquired in the IR range (0.8-5.1 μm). To characterize the global variations of spectral indicators across Dione' surface, we divided it into a 1°x1° grid and then averaged the band depths and peak values inside each square cell.We will investigate if there exist a correspondence with water ice abundance variations by producing water ice' absorption band depths at 1.25, 1.52 and 2.02 μm, and with surface morphology by comparing the results with ISS color maps in the ultraviolet, visible and infrared

  14. Magnetic trapping of superconducting submicron particles produced by laser ablation in superfluid helium

    Science.gov (United States)

    Takahashi, Yuta; Suzuki, Junpei; Yoneyama, Naoya; Tokawa, Yurina; Suzuki, Nobuaki; Matsushima, Fusakazu; Kumakura, Mitsutaka; Ashida, Masaaki; Moriwaki, Yoshiki

    2017-02-01

    We produced spherical superconducting submicron particles by laser ablation of their base metal tips in superfluid helium, and trapped them using a quadrupole magnetic field owing to the diamagnetism caused by the Meissner effect. We also measured their critical temperatures of superconductivity, by observing the threshold temperatures for the confinement of superconducting submicron particles in the trap.

  15. Simulation of sub-micron particle formation and growth during combustion processes

    Institute of Scientific and Technical Information of China (English)

    WEI Feng; ZHANG Junying; ZHENG Chuguang

    2005-01-01

    Sub-micron particle formation and growth during combustion processes is very complex because of its strong uncertainty and randomness. A model to simulate the sub-micron particle formation and growth during the combustion process is developed based on the gas kinetic theory and is expressed by the vapor concentration changes and particle loading changes, which reflects effect characteristics of different mechanism (nucleation, condensation and coagulation) in particle formation processes. The developed characteristic time is used to token the three mechanisms. It is thought that environmental temperature and pressure, vapor temperature and critical pressure are important factors influencing the sub-micron particle formation and growth. The sub-micron particle formation processes under different conditions are studied and the effect characteristics of these mechanisms are analyzed, which show that the nucleation, condensation,and coagulation occur simultaneously during the sub-micron particle formation and growth process. Nucleation contributes to the sub-micron particle formation, while condensation and coagulation is helpful to the growth of the particle size.

  16. Development of microstructure in submicron particles reinforced magnesium matrix composite processed by room temperature deformation

    Energy Technology Data Exchange (ETDEWEB)

    Nie, K.B., E-mail: kaibo.nie@gmail.com [College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Deng, K.K., E-mail: jamsdk@163.com [College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Xu, F.J. [College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Wang, X.J.; Wu, K. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)

    2015-01-15

    Magnesium matrix composite reinforced with submicron SiC particles was subjected to room temperature deformation. A stepped tensile method was adopted to observe the development of microstructure at different tensile strain state. The microstructure evolution determined by transmission electron microscopy showed that the existence of submicron SiC particles could promote dislocation multiplication as well as impede dislocation motion. Dislocation density around SiC particles increased with the increase of tensile strain. Compared with the matrix alloy, the composite could withstand greater external loads, which can be related to the pinning effect caused by the submicron SiC particles on the movement of grain and twin boundaries. The study of the interface between the submicron SiC particles and matrix in the composite suggested that single submicron SiC particle bonded well with the matrix alloy after tensile process. Initiation of micro-cracks usually generated in the submicron particle dense zone during tensile process, which could lead to the fracture of composite. - Highlights: • Interaction among SiCp, dislocations, grain boundaries and twinning is analyzed. • Microstructures of SiCp/AZ91 during tensile is characterized. • 0.2 μm SiCp has significant pinning effect on dislocation movement. • Interfacial bonding between 0.2 μm SiCp-Mg is analyzed.

  17. Deciphering sub-micron ice particles on Enceladus surface

    Science.gov (United States)

    Scipioni, F.; Schenk, P.; Tosi, F.; D'Aversa, E.; Clark, R.; Combe, J.-Ph.; Ore, C. M. Dalle

    2017-07-01

    The surface of Saturn's moon Enceladus is composed primarily by pure water ice. The Cassini spacecraft has observed present-day geologic activity at the moon's South Polar Region, related with the formation and feeding of Saturn's E-ring. Plumes of micron-sized particles, composed of water ice and other non-ice contaminants (e.g., CO2, NH3, CH4), erupt from four terrain's fractures named Tiger Stripes. Some of this material falls back on Enceladus' surface to form deposits that extend to the North at ∼40°W and ∼220°W, with the highest concentration found at the South Pole. In this work we analyzed VIMS-IR data to identify plumes deposits across Enceladus' surface through the variation in band depth of the main water ice spectral features. To characterize the global variation of water ice band depths across Enceladus, the entire surface was sampled with an angular resolution of 1° in both latitude and longitude, and for each angular bin we averaged the value of all spectral indices as retrieved by VIMS. The position of the plumes' deposits predicted by theoretical models display a good match with water ice band depths' maps on the trailing hemisphere, whereas they diverge significantly on the leading side. Space weathering processes acting on Enceladus' surface ionize and break up water ice molecules, resulting in the formation of particles smaller than one micron. We also mapped the spectral indices for sub-micron particles and we compared the results with the plumes deposits models. Again, a satisfactory match is observed on the trailing hemisphere only. Finally, we investigated the variation of the depth of the water ice absorption bands as a function of the phase angle. In the visible range, some terrains surrounding the Tiger Stripes show a decrease in albedo when the phase angle is smaller than 10°. This unusual effect cannot be confirmed by near infrared data, since observations with a phase angle lower than 10° are not available. For phase angle

  18. Numerical Investigation of Evaporation Induced Self-Assembly of Sub-Micron Particles Suspended in Water

    CERN Document Server

    Tayeb, Raihan; Zhang, Yuwen

    2016-01-01

    Self-assembly of sub-micron particles suspended in a water film is investigated numerically. The liquid medium is allowed to evaporate leaving only the sub-micron particles. A coupled CFD-DEM approach is used for the simulation of fluid-particle interaction. Momentum exchange and heat transfer between particles and fluid and among particles are considered. A history dependent contact model is used to compute the contact force among sub-micron particles. Simulation is done using the open source software package CFDEM which basically comprises of two other open source packages OpenFOAM and LIGGGHTS. OpenFOAM is a widely used solver for CFD related problems. LIGGGHTS, a modification of LAMMPS, is used for DEM simulation of granular materials. The final packing structure of the sub-micron particles is discussed in terms of distribution of coordination number and radial distribution function (RDF). The final packing structure shows that particles form clusters and exhibit a definite pattern as water evaporates awa...

  19. Development of enteric submicron particle formulation of papain for oral delivery

    Directory of Open Access Journals (Sweden)

    Sharma M

    2011-09-01

    Full Text Available Manu Sharma1, Vinay Sharma2, Amulya K Panda3, Dipak K Majumdar41Department of Pharmacy, Banasthali Vidhyapith, Banasthali, India; 2Department of Bioscience and Biotechnology, Banasthali Vidhyapith, Banasthali, India; 3National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, India; 4Department of Pharmaceutics, Delhi Institute of Pharmaceutical Sciences and Research, University of Delhi, New Delhi, IndiaBackground: Particulate systems have received increasing attention for oral delivery of biomolecules. The objective of the present study was to prepare submicron particulate formulations of papain for pH-dependent site-specific release using pH-sensitive polymers.Methods: Enteric submicron particle formulations of papain were prepared by w/o/w emulsion solvent evaporation using hydroxypropyl methylcellulose phthalate (HPMCP, Eudragit L100, and Eudragit S100, to avoid gastric inactivation of papain.Results: Smaller internal and external aqueous phase volumes provided maximum encapsulation efficiency (75.58%–82.35%, the smallest particle size (665.6–692.4 nm, and 25%–30% loss of enzyme activity. Release studies in 0.1 N HCl confirmed the gastroresistance of the formulations. The anionic submicron particles aggregated in 0.1 N HCl (ie, gastric pH 1.2 due to protonation of carboxylic groups in the enteric polymer. Aggregates < 500 µm size would not impede gastric emptying. However, at pH > 5.0 (duodenal pH, the submicron particles showed deaggregation due to restoration of surface charge. HPMCP submicron particles facilitated almost complete release of papain within 30 minutes at pH 6.0, while Eudragit L100 and Eudragit S100 particles released 88.82% and 53.00% of papain at pH 6.8 and pH 7.4, respectively, according to the Korsmeyer–Peppas equation. Sodium dodecyl sulfate polyacrylamide gel electrophoresis and fluorescence spectroscopy confirmed that the structural integrity of the enzyme was maintained during encapsulation. Fourier

  20. Continuous separation of submicron particles using Angled electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Yunus, Nurul A Md; Green, Nicolas G [Nano Research Group, School of Electronics and Computer Science, University of Southampton, SO17 1BJ (United Kingdom)], E-mail: ng2@ecs.soton.ac.uk

    2008-12-01

    Dielectrophoretic separation of particles is achieved by the generation of electric forces on the particles by non-uniform electric fields. This paper presents a technique based on negative dielectrophoresis in a novel design of electrode array for the non-contact separation of polarisable particles. Angled electrodes are used to generate a lateral force in a microfluidic channel separating a mixed stream of particles into distinct streams of constituent components and achieving a high degree of spatial separation.

  1. Lungs deposition and pharmacokinetic study of submicron budesonide particles in Wistar rats intended for immediate effect in asthma.

    Science.gov (United States)

    Rauf, Abdul; Bhatnagar, Aseem; Sisodia, S S; Khar, Roop K; Ahmad, Farhan J

    2017-01-01

    The purpose of the present investigation was to study the aerosolization, lungs deposition and pharmacokinetic study of inhalable submicron particles of budesonide in male Wistar rats. Submicron particles were prepared by antisolvent nanoprecipitation method and freeze-dried to obtain free flowing powder. The freeze-drying process yielded dry powder with desirable aerodynamic properties for inhalation therapy. An in-house model inhaler was designed to deliver medicine to lungs, optimized at dose level of 10 mg for 30 sec of fluidization. The in vitro aerosolization study demonstrates that submicron particles dissolve faster with improved aerosolization effect as compared to micronized budesonide. Both submicron and micron particles were compared for in vivo lungs deposition. The results showed that relatively high quantity of submicron particles reaches deep into the lungs as compared to micron particles. Most pronounced effect observed with submicron particles from pharmacokinetic parameters was the enhancement in peak plasma concentration (Cmax) by 28.85 %, and increase in area under concentration curve (AUC0-8h) by 30.33 % compared to micron sized particles. The results suggested that developed submicronized formulation of budesonide can be used for pulmonary drug delivery for high deposition to deep lungs tissues.

  2. Study of Submicron Particle Size Distribution by Laser Doppler Measurement of Brownian Motion.

    Science.gov (United States)

    1987-01-30

    regime considered here, heat transfer from the submicron particles by forced convection and natural convection are negligible due to the extremely small...physical processes begin to influence the Brownian motion characteristics at high laser beam intensity. An analysis of the effects of thermophoresis and...photon pressure was carried out. The effect of thermophoresis due to the uneven heating of the particle by the laser beam was found to be a major

  3. Submicron particle dynamics for different surfaces under quiescent and turbulent conditions

    Science.gov (United States)

    Vohra, Karn; Ghosh, Kunal; Tripathi, S. N.; Thangamani, I.; Goyal, P.; Dutta, Anu; Verma, V.

    2017-03-01

    Experiments were conducted using CsI aerosols in a small scale test chamber to simulate behaviour of aerosols in the containment of a nuclear reactor. The primary focus of the study was on submicron particles (14.3 nm-697.8 nm) due to their hazardous effect on human health. Different wall surfaces, viz., plexiglass, concrete and sandpaper were chosen to study the effect of surface roughness on dry deposition velocity under both quiescent and turbulent conditions. An analytical approach to calculate dry deposition velocity of submicron particles for rough surfaces has been proposed with an improvement in the existing parameterization for shift in the velocity boundary layer. The predicted deposition velocity with the improved parameterization was found to have better agreement with published measured data of Lai and Nazaroff (2005) compared to the existing parameterizations (Wood, 1981; Zhao and Wu, 2006b). There was a significant reduction in root mean square error (RMSE) between predicted, using the improved parameterization and measured deposition velocity (upto 100%) compared to earlier ones. The new analytical deposition approach was coupled with volume conserving semi-implicit coagulation model. This aerosol dynamic model was evaluated against explicit particle size distribution for the first time for rough surfaces. Normalized RMSE between simulated and measured particle size distribution varied in the range of 2%-20% at different instances. The model seems to closely predict submicron particle behaviour in indoor environment.

  4. Virtual Impactor for Sub-micron Aerosol Particles

    Science.gov (United States)

    Bolshakov, A. A.; Strawa, A. W.; Hallar, A. G.

    2005-12-01

    The objective of a virtual impactor is to separate out the larger particles in a flow from the smaller particles in such a way that both sizes of particles are available for sampling. A jet of particle-laden air is accelerated toward a collection probe so that a small gap exists between the acceleration nozzle and the probe. A vacuum is applied to deflect a major portion of the airstream away form the collection probe. Particles larger than a certain size have sufficient momentum so that they cross the deflected streamlines and enter the collection probe, whereas smaller particles follow the deflected streamlines. The result is that the collection probe will contain a higher concentration of larger particles than is in the initial airstream. Typically, virtual impactors are high-flow devices used to separate out particles greater than several microns in diameter. We have developed a special virtual impactor to concentrate aerosol particles of diameters between 0.5 to 1 micron for the purpose of calibrating the optical cavity ring-down instrument [1]. No similar virtual impactors are commercially available. In our design, we have exploited considerations described earlier [2-4]. Performance of our virtual impactor was evaluated in an experimental set-up using TSI 3076 nebulizer and TSI 3936 scanning mobility particle size spectrometer. Under experimental conditions optimized for the best performance of the virtual impactor, we were able to concentrate the 700-nm polystyrene particles no less than 15-fold. However, under experimental conditions optimized for calibrating our cavity ring-down instrument, a concentration factor attainable was from 4 to 5. During calibration experiments, maximum realized particle number densities were 190, 300 and 1600 cm-3 for the 900-nm, 700-nm and 500-nm spheres, respectively. This paper discusses the design of the impactor and laboratory studies verifying its performance. References: 1. A.W. Strawa, R. Castaneda, T. Owano, D.S. Baer

  5. Multifractal analysis of atmospheric sub-micron particle data

    Science.gov (United States)

    Arizabalo, Rubén Darío; González-Ávalos, Eugenio; Korvin, Gabor

    2015-03-01

    Multifractal analysis was used to describe air pollution by sub-micrometric atmospheric particles. Atmospheric particle concentrations were studied from March 31 to April 21, 2006, as part of the MILAGRO campaign at the Jasso Station by means of an SMPS. Sixteen campaign days were selected to carry out the multifractal analysis of the experimental data through Singularity Spectra f(α). In this work, the roughness/smoothness feature of atmospheric particle distributions was studied by means of the Hölder exponent (α), which can be associated with the intensity of particle emissions through time and the randomness of the external emission sources. Multifractal analysis has been found to be a useful tool to establish intensity fluctuations of atmospheric data.

  6. Strong magnetic response of submicron Silicon particles in the infrared

    CERN Document Server

    Garcia-Etxarri, A; Froufe-Perez, L S; Lopez, C; Chantada, L; Scheffold, F; Aizpurua, J; Nieto-Vesperinas, M; Saenz, J J

    2010-01-01

    High-permittivity dielectric particles with resonant magnetic properties are being explored as constitutive elements of new metamaterials and devices in the microwave regime. Magnetic properties of low-loss dielectric nanoparticles in the visible or infrared are not expected due to intrinsic low refractive index of optical materials in these regimes. Here we analyze the dipolar electric and magnetic response of loss-less dielectric spheres made of moderate permittivity materials. For low material refractive index there are no sharp resonances due to strong overlapping between different multipole contributions. However, we find that Silicon particles with refractive index 3.5 and radius approx. 200nm present a dipolar and strong magnetic resonant response in telecom and near-infrared frequencies, (i.e. at wavelengths approx. 1.2-2 micrometer). Moreover, the light scattered by these Si particles can be perfectly described by dipolar electric and magnetic fields, quadrupolar and higher order contributions being ...

  7. Experimental investigation of submicron and ultrafine soot particle removal by tree leaves

    Science.gov (United States)

    Hwang, Hee-Jae; Yook, Se-Jin; Ahn, Kang-Ho

    2011-12-01

    Soot particles emitted from vehicles are one of the major sources of air pollution in urban areas. In this study, five kinds of trees were selected as Pinus densiflora, Taxus cuspidata, Platanus occidentalis, Zelkova serrata, and Ginkgo biloba, and the removal of submicron (densiflora showed the greatest deposition velocity, followed by T. cuspidata, Platanus occidentalis, Zelkova serrata, and Ginkgo biloba. In addition, from the comparison of deposition velocity between two groups of Platanus occidentalis leaves, i.e. one group of leaves with front sides only and the other with back sides only, it was supposed in case of the broadleaf trees that the removal of airborne soot particles of submicron and ultrafine sizes could be affected by the surface roughness of tree leaves, i.e. the veins and other structures on the leaves.

  8. Carbohydrate-Like Composition of Submicron Atmospheric Particles and their Production from Ocean Bubble Bursting

    Science.gov (United States)

    Russell, L. M.; Hawkins, L. N.; Frossard, A. A.; Quinn, P.; Bates, T. S.

    2009-12-01

    Oceans cover over two-thirds of the Earth’s surface, and the particles emitted to the atmosphere by waves breaking on sea surfaces provide an important contribution to the planetary albedo. During the ICEALOT cruise on the R/V Knorr in March and April of 2008, organic mass accounted for 15% to 47% of the submicron particle mass in the air masses sampled over the North Atlantic and Arctic Oceans. A majority of this organic component (0.1 to 0.4 μg m-3) consisted of organic hydroxyl (including polyol and other alcohol) groups characteristic of saccharides, similar to biogenic carbohydrates found in seawater. The large fraction of organic hydroxyl groups measured during ICEALOT in submicron atmospheric aerosol exceeded those measured in most previous campaigns but were similar to particles in marine air masses in the open ocean (Southeast Pacific Ocean) and coastal sites at northern Alaska (Barrow) and northeastern North America (Appledore Island and Chebogue Point). The ocean-derived organic hydroxyl mass concentration during ICEALOT correlated strongly to submicron Na concentration and wind speed. The observed submicron particle ratios of marine organic mass to Na were enriched by factors of ~100 to ~1000 over reported sea surface organic to Na ratios, suggesting that the surface-controlled process of film bursting is influenced by the dissolved organic components present in the sea surface micro-layer. Both marine organic components and Na increased with increasing number mean diameter of the accumulation mode, suggesting a possible link between organic components in the ocean surface and aerosol-cloud interactions.

  9. Generation of sub-micron particles and secondary pollutants from building materials by ozone reaction

    Science.gov (United States)

    Aoki, Taisuke; Tanabe, Shin-ichi

    This study reports results from two different experiments examining reactions between ozone and common building materials that can lead to the formation of secondary products and particulate-phase materials. Monitored species include sub-micron particles and volatile organic compounds (VOCs). In the first set of experiments, various building materials were placed in a 20 L stainless-steel chamber and exposed to ozone. The materials included expanded polystyrene, a natural rubber adhesive, cedar board, Japanese Cyprus board and silver fir board, as well as d-limonene, which is a known constituent of certain woods and cleaning products. The combination of ozone and either d-limonene, cedar board or cypress board produced sub-micron particles, with most of the increase occurring in the size range of 0.01- 0.5μm diameter. This was not observed for the other materials. In the case of cedar board, the consequence of ozone exposure over an extended time interval was monitored. As the exposure time elapsed, the concentration of sub-micron particles moderately decreased. In the second set of experiments, unwaxed or waxed plastic tiles were placed in the 20 L chamber and exposed to ozone. Sub-micron particles and organic compounds were measured during the course of the experiments. In the case of the waxed tile, the number of 0.01- 1.0μm size particles grew about 50×108particlesm-3; particle growth was significantly less for the un-waxed tile. For both the waxed and un-waxed tiles, the emission rates of heptane, nonane, nonanal, and decanal increased after ozone was added to the supply air. (However, it is not clear if some or all of this production was due to ozone reacting with the sorbent used for sampling or with compounds captured by the sorbent.) This study provides further evidence that ozone-initiated reactions with building materials can be a significant source of both sub-micron particles and secondary organic compounds in indoor environments.

  10. Nano-ring arrays for sub-micron particle trapping

    Science.gov (United States)

    Han, Xue; Truong, Viet Giang; Nic Chormaic, Síle

    2017-04-01

    Plasmonic tweezers based on nano-ring arrays on gold thin film are demonstrated. A cylindrical surface plasmon resonance is generated in the aperture of a nano-ring and a transmission peak results. When nano-slits are included to connect the nano-rings, the transmission peak becomes narrower. When the size of the aperture of the nano-ring is reduced, this peak is red-shifted. Both 0.5 μm and 1 μm polystyrene particles are trapped successfully by nano-ring arrays. A self-induced back-action effect is observed when a red-shifted laser beam is used. With multiple trapping sites provided by the nano-ring array, this type of plasmonic tweezers has huge potential to be integrated in lab-on-a-chip systems for life sciences research.

  11. Physics of sub-micron cosmic dust particles

    Science.gov (United States)

    Roy, N. L.

    1974-01-01

    Laboratory tests with simulated micrometeoroids to measure the heat transfer coefficient are discussed. Equations for ablation path length for electrically accelerated micrometeoroids entering a gas target are developed which yield guidelines for the laboratory measurement of the heat transfer coefficient. Test results are presented for lanthanum hexaboride (LaB sub 6) microparticles in air, argon, and oxygen targets. The tests indicate the heat transfer coefficient has a value of approximately 0.9 at 30 km/sec, and that it increases to approximately unity at 50 km/sec and above. Test results extend to over 100 km/sec. Results are also given for two types of small particle detectors. A solid state capacitor type detector was tested from 0.61 km/sec to 50 km/sec. An impact ionization type detector was tested from 1.0 to 150 km/sec using LaB sub 6 microparticles.

  12. Size-selective separation of submicron particles in suspensions with ultrasonic atomization.

    Science.gov (United States)

    Nii, Susumu; Oka, Naoyoshi

    2014-11-01

    Aqueous suspensions containing silica or polystyrene latex were ultrasonically atomized for separating particles of a specific size. With the help of a fog involving fine liquid droplets with a narrow size distribution, submicron particles in a limited size-range were successfully separated from suspensions. Performance of the separation was characterized by analyzing the size and the concentration of collected particles with a high resolution method. Irradiation of 2.4MHz ultrasound to sample suspensions allowed the separation of particles of specific size from 90 to 320nm without regarding the type of material. Addition of a small amount of nonionic surfactant, PONPE20 to SiO2 suspensions enhanced the collection of finer particles, and achieved a remarkable increase in the number of collected particles. Degassing of the sample suspension resulted in eliminating the separation performance. Dissolved air in suspensions plays an important role in this separation.

  13. Microstructural and electromagnetic properties of MnO2 coated nickel particles with submicron size

    Institute of Scientific and Technical Information of China (English)

    Tang Bao-Lin; He Jun; Ji Tian-Hao; Wang Xin-Lin

    2009-01-01

    Nickel particles with submicron size are prepared by using the solvothermal method. These spheres are then coated with a layer of MnO2 using the soft chemical method. The microstructure is characterized by x-ray diffraction,transmission electron microscopy, and scanning electron microscopy. Energy x-ray dispersive spectrometry and high-resolution images show that the granular composites have a classical core/shell structure with an MnO2 superficial layer, no more than 10 nm in thickness. The hysteresis measurements indicate that these submicron-size Ni composite powders have small remanence and moderate coercivity. The electromagnetic properties of the powders measured by a vector network analyzer in a frequency range of 2-18 GHz are also reported in detail.

  14. RESEARCH THE DEPOSITION NANO- AND SUBMICRON PARTICLES OF TOBACCO SMOKE ON AIRWAY

    Directory of Open Access Journals (Sweden)

    V. I. Timoshenko

    2014-01-01

    Full Text Available The features of deposition of highly dispersed particles of smoke on nanoscale biological airway surface on the example of tobacco smoke are considering. A model of particle deposition of the nicotine gum along the way through the smoke inhaled. Obtain a solution of the equation for the diffusion flux changes deposited nano- and submicron particles through hydrodynamic boundary layer.The particle deposition of nicotine gum on the airways by scanning the distribution of nanoparticles deposited using an atomic force microscope SobverPRO was experimentally studied. Patterns of distribution of nanoparticles dispersed smoke 4 species of tobacco in different parts of the respiratory tract were obtained. That allowed to talk about the absence of the effect of coagulation of the airway. It was established that the child as a passive smoker particle deposition diffusive flux of nicotine is proportionally higher than adult because the channel width is less than the airways than in adults.

  15. Comparative evaluation of dental resin composites based on micron- and submicron-sized monomodal glass filler particles.

    Science.gov (United States)

    Valente, Lisia L; Peralta, Sonia L; Ogliari, Fabrício A; Cavalcante, Larissa M; Moraes, Rafael R

    2013-11-01

    A model resin composite containing a novel monomodal inorganic filler system based on submicron-sized Ba-Si-Al glass particles (NanoFine NF180; Schott) was formulated and compared with an experimental composite containing micron-sized particles (UltraFine UF1.0; Schott). The filler particles were characterized using X-ray microanalysis and granulometry, while the composites were characterized in terms of filler-resin morphology, radiopacity, degree of CC conversion, hardness, flexural strength/modulus, work-of-fracture, surface roughness and gloss (before and after simulated toothbrushing abrasion), and bulk compressive creep. The composites were formulated from the same photoactivated dimethacrylate co-monomer, incorporating mass fractions of 75% micron- and 78% submicron-sized particles. Quantitative data were analyzed at a significance level of pcomposites were similar in radiopacity, flexural strength, work-of-fracture, and creep. The submicron composite was harder but had lower flexural modulus and CC conversion. No significant differences in roughness were observed before brushing, although the submicron composite had higher gloss. Brushing increased roughness and decreased gloss on both materials, but the submicron composite retained higher gloss after brushing. The monomodal submicron glass filler system demonstrated potential for use in restorative dental composites, particularly due to improved esthetic properties. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  16. Emission of submicron aerosol particles in cement kilns: Total concentration and size distribution.

    Science.gov (United States)

    Rotatori, Mauro; Mosca, Silvia; Guerriero, Ettore; Febo, Antonio; Giusto, Marco; Montagnoli, Mauro; Bianchini, Massimo; Ferrero, Renato

    2015-01-01

    Cement plants are responsible for particle and gaseous emissions into the atmosphere. With respect to particle emission, the greater part of is in the range from 0.05 to 5.0 µm in diameter. In the last years attention was paid to submicron particles, but there is a lack of available data on the emission from stationary sources. In this paper, concentration and size distribution of particles emitted from four cement kilns, in relationship to operational conditions (especially the use of alternative fuel to coal) of the clinker process are reported. Experimental campaigns were carried out by measuring particles concentration and size distribution at the stack of four cement plants through condensation particle counter (CPC) and scanning mobility particle sizer spectrometer (SMPS). Average total particle number concentrations were between 2000 and 4000 particles/cm³, about 8-10 times lower that those found in the corresponding surrounding areas. As for size distribution, for all the investigated plants it is stable with a unimodal distribution (120-150 nm), independent from the fuel used.

  17. Submicron particle mass concentrations and sources in the Amazonian wet season (AMAZE-08)

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Q.; Farmer, D. K.; Rizzo, L. V.; Pauliqueivis, T.; Kuwata, Mikinori; Karl, Thomas G.; Guenther, Alex B.; Allan, James D.; Coe, H.; Andreae, M. O.; Poeschl, U.; Jiminez, J. L.; Artaxo, Paulo; Martin, Scot T.

    2015-01-01

    Real-time mass spectra of non-refractory component of submicron aerosol particles were recorded in a tropical rainforest in the central Amazon basin during the wet season of 2008, as a part of the Amazonian Aerosol Characterization Experiment (AMAZE-08). Organic components accounted on average for more than 80% of the non-refractory submicron particle mass concentrations during the period of measurements. Ammonium was present in sufficient quantities to halfway neutralize sulfate. In this acidic, isoprene-dominated, low-NOx environment the high-resolution mass spectra as well as mass closures with ion chromatography measurements did not provide evidence for significant contributions of organosulfate species, at least at concentrations above uncertainty levels. Positive-matrix factorization of the time series of particle mass spectra identified four statistical factors to account for the variance of the signal intensities of the organic constituents: a factor HOA having a hydrocarbon-like signature and identified as regional emissions of primary organic material, a factor OOA-1 associated with fresh production of secondary organic material by a mechanism of BVOC oxidation followed by gas-to-particle conversion, a factor OOA-2 consistent with reactive uptake of isoprene oxidation products, especially epoxydiols by acidic particles, and a factor OOA-3 associated with long range transport and atmospheric aging. The OOA-1, -2, and -3 factors had progressively more oxidized signatures. Diameter-resolved mass spectral markers also suggested enhanced reactive uptake of isoprene oxidation products to the accumulation mode for the OOA-2 factor, and such size partitioning can be indicative of in-cloud process. The campaign-average factor loadings were in a ratio of 1.1:1.0 for the OOA-1 compared to the OOA-2 pathway, suggesting the comparable importance of gas-phase compared to particle-phase (including cloud waters) production pathways of secondary organic material during

  18. The role of jet and film drops in controlling the mixing state of submicron sea spray aerosol particles

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiaofei; Deane, Grant B.; Moore, Kathryn A.; Ryder, Olivia S.; Stokes, M. Dale; Beall, Charlotte M.; Collins, Douglas B.; Santander, Mitchell V.; Burrows, Susannah M.; Sultana, Camille M.; Prather, Kimberly

    2017-07-03

    Covering 71% of the Earth’s surface, oceans represent a significant global source of atmospheric aerosols. The size and composition of sea spray aerosols (SSA) affect their ability to serve as cloud seeds and thus understanding the factors controlling their composition is critical to predicting their impact on clouds and climate. SSA particles have been shown to be an external mixture of particles with different compositions. Film and jet drop production mechanisms ultimately determine the individual particle compositions which are comprised of an array of salt/organic mixtures ranging from pure sea salt to nearly pure organic particles. It is often assumed that the majority of submicron SSA are formed by film drops produced from bursting hydrophobic organic-rich bubble film caps at the sea surface, and in contrast, jet drops are postulated to produce larger supermicron particles from underlying seawater comprised largely of salts and water soluble organic species. However, here we show that jet drops produced by bursting sub-100 m bubbles account for up to 40 % of all submicron particles. They have distinct chemical compositions, organic volume fractions and ice nucleating activities from submicron film drops. Thus a substantial fraction of submicron particles will not necessarily be controlled by the composition of the sea surface microlayer as has been assumed in many studies. This finding has significant ramifications for the size-resolved mixing states of SSA particles which must be taken into consideration when accessing SSA impacts on clouds.

  19. Thermal, structural and morphological properties of High Density Polyethylene matrix composites reinforced with submicron agro silica particles and Titania particles

    Directory of Open Access Journals (Sweden)

    Oluyemi O. Daramola

    2017-07-01

    Full Text Available HDPE—based composites samples filled with 2, 4, 6, 8 and 10 wt.% submicron agro-waste silica particles extracted from rice husk ash (RHA at constant 0.3 wt.% Titania loading were prepared using rapra single screw extruder at temperature of 200–230 °C. The extrudates were compressed with a laboratory carver press at a temperature of 230 °C for 10 min under applied pressure of 0.2 kPa and water cooled at 20 °C min−1. Thermal, structural and morphological properties of the composites were studied. The results of the thermogravimetric analysis (TGA revealed that the composites with 10 wt.% SiO2 have the best maximum thermal degradation temperature of 438.73 °C. The crystal structure of neat HDPE, and the siliceous composites developed revealed two obvious diffractive peaks of about 21.3° and 23.7° corresponding to typical crystal plane (1 1 0 and (2 0 0 of orthorhombic phase respectively. The diffractive peaks do not shift with the addition of silica particles; this clearly indicates that the addition of silica particles did not exert much effect on the crystalline structure of HDPE. There is no much difference in the interplanar distance (d-value. Lamellar thickness (L of HDPE increases with the addition of silica particles, which implies that silica particles aid the formation of more perfect crystals. Scanning electron microscopy studies indicated that there were chains inter diffusion and entanglement between HDPE matrix and the silica particles at lower weight fraction (2–4 wt.% of submicron silica particles which resulted into homogeneous dispersion of the particles within the matrix.

  20. Design and Analysis of an Isokinetic Sampling Probe for Submicron Particle Measurements at High Altitude

    Science.gov (United States)

    Heath, Christopher M.

    2012-01-01

    An isokinetic dilution probe has been designed with the aid of computational fluid dynamics to sample sub-micron particles emitted from aviation combustion sources. The intended operational range includes standard day atmospheric conditions up to 40,000-ft. With dry nitrogen as the diluent, the probe is intended to minimize losses from particle microphysics and transport while rapidly quenching chemical kinetics. Initial results indicate that the Mach number ratio of the aerosol sample and dilution streams in the mixing region is an important factor for successful operation. Flow rate through the probe tip was found to be highly sensitive to the static pressure at the probe exit. Particle losses through the system were estimated to be on the order of 50% with minimal change in the overall particle size distribution apparent. Following design refinement, experimental testing and validation will be conducted in the Particle Aerosol Laboratory, a research facility located at the NASA Glenn Research Center to study the evolution of aviation emissions at lower stratospheric conditions. Particle size distributions and number densities from various combustion sources will be used to better understand particle-phase microphysics, plume chemistry, evolution to cirrus, and environmental impacts of aviation.

  1. Size-Dependent Photodynamic Anticancer Activity of Biocompatible Multifunctional Magnetic Submicron Particles in Prostate Cancer Cells.

    Science.gov (United States)

    Choi, Kyong-Hoon; Nam, Ki Chang; Malkinski, Leszek; Choi, Eun Ha; Jung, Jin-Seung; Park, Bong Joo

    2016-09-06

    In this study, newly designed biocompatible multifunctional magnetic submicron particles (CoFe₂O₄-HPs-FAs) of well-defined sizes (60, 133, 245, and 335 nm) were fabricated for application as a photosensitizer delivery agent for photodynamic therapy in cancer cells. To provide selective targeting of cancer cells and destruction of cancer cell functionality, basic cobalt ferrite (CoFe₂O₄) particles were covalently bonded with a photosensitizer (PS), which comprises hematoporphyrin (HP), and folic acid (FA) molecules. The magnetic properties of the CoFe₂O₄ particles were finely adjusted by controlling the size of the primary CoFe₂O₄ nanograins, and secondary superstructured composite particles were formed by aggregation of the nanograins. The prepared CoFe₂O₄-HP-FA exhibited high water solubility, good MR-imaging capacity, and biocompatibility without any in vitro cytotoxicity. In particular, our CoFe₂O₄-HP-FA exhibited remarkable photodynamic anticancer efficiency via induction of apoptotic death in PC-3 prostate cancer cells in a particle size- and concentration-dependent manner. This size-dependent effect was determined by the specific surface area of the particles because the number of HP molecules increased with decreasing size and increasing surface area. These results indicate that our CoFe₂O₄-HP-FA may be applicable for photodynamic therapy (PDT) as a PS delivery material and a therapeutic agent for MR-imaging based PDT owing to their high saturation value for magnetization and superparamagnetism.

  2. Quantitative cellular uptake of double fluorescent core-shelled model submicronic particles

    Energy Technology Data Exchange (ETDEWEB)

    Leclerc, Lara, E-mail: leclerc@emse.fr [Ecole Nationale Superieure des Mines, CIS-EMSE, LINA (France); Boudard, Delphine [LINA (France); Pourchez, Jeremie; Forest, Valerie [Ecole Nationale Superieure des Mines, CIS-EMSE, LINA (France); Marmuse, Laurence; Louis, Cedric [NANO-H S.A.S (France); Bin, Valerie [LINA (France); Palle, Sabine [Universite Jean Monnet, Centre de Microscopie Confocale Multiphotonique (France); Grosseau, Philippe; Bernache-Assollant, Didier [Ecole Nationale Superieure des Mines, CIS-EMSE, LINA (France); Cottier, Michele [LINA (France)

    2012-11-15

    The relationship between particles' physicochemical parameters, their uptake by cells and their degree of biological toxicity represent a crucial issue, especially for the development of new technologies such as fabrication of micro- and nanoparticles in the promising field of drug delivery systems. This work was aimed at developing a proof-of-concept for a novel model of double fluorescence submicronic particles that could be spotted inside phagolysosomes. Fluorescein isothiocyanate (FITC) particles were synthesized and then conjugated with a fluorescent pHrodo Trade-Mark-Sign probe, red fluorescence of which increases in acidic conditions such as within lysosomes. After validation in acellular conditions by spectral analysis with confocal microscopy and dynamic light scattering, quantification of phagocytosis was conducted on a macrophage cell line in vitro. The biological impact of pHrodo functionalization (cytotoxicity, inflammatory response, and oxidative stress) was also investigated. Results validate the proof-of-concept of double fluorescent particles (FITC + pHrodo), allowing detection of entirely engulfed pHrodo particles (green and red labeling). Moreover incorporation of pHrodo had no major effects on cytotoxicity compared to particles without pHrodo, making them a powerful tool for micro- and nanotechnologies.

  3. Submicron-sized boron carbide particles encapsulated in turbostratic graphite prepared by laser fragmentation in liquid medium.

    Science.gov (United States)

    Ishikawa, Yoshie; Sasaki, Takeshi; Koshizaki, Naoto

    2010-08-01

    Submicron-sized B4C spherical particles were obtained by laser fragmentation of large B4C particles dispersed in ethyl acetate. The irradiated surface of large B4C raw particles was heated and melted by laser energy absorption. B4C droplets were then cooled down, and finally B4C spherical particles were obtained. Moreover, each B4C particle obtained was encapsulated in a graphitic layer that is useful for medical functionalization of particles. Thus, obtained B4C particles encapsulated in graphitic layer may have potential uses in boron neutron capture therapy.

  4. Speciation of atmospheric polycyclic aromatic hydrocarbons (PAHs) present during fog time collected submicron particles.

    Science.gov (United States)

    Singh, Dharmendra Kumar; Sharma, Swati; Habib, Gazala; Gupta, Tarun

    2015-08-01

    Airborne submicron particles (PM1) were collected using PM1 sampler during the fog-dominated days (December 2013-January 2014). PM1 values varied between 58.12 μg/m(3) and 198.75 μg/m(3), and average mass concentration was 162.33 ± 38.25 μg/m(3) while total average concentration of particle-associated polycyclic aromatic hydrocarbon (PAHs) determined was 616.31 ± 30.31 ng/m(3). This is a signal for an alarming high pollution level at this site situated in the Indo-Gangetic Plain (IGP). PAHs were extracted from filters using toluene and acetonitrile. Quantitative measurements of polycyclic aromatic hydrocarbons (PAHs) were carried out using the high performance liquid chromatography (HPLC) technique. The extracts were analyzed for 16 target polycyclic aromatic hydrocarbons (PAHs) including carcinogenic compound benzo(a)pyrene (19.86 ± 38.98 ng/m(3)). Fluoranthene, benzo(a)anthracene, anthracene, and fluorene were the predominant compounds found in the samples collected during foggy days. Based on number of rings, four-ring PAH compounds had maximum contribution (43%) in this fog time collected submicron particles followed by three-ring (21%), five-ring (20%), six-ring (13%), and two-ring (3%), respectively. In winter and foggy days, wood and coal combustion and biomass burning also significantly contribute to the PAH levels. However, diagnostic ratio suggests diesel emissions as the prime source of PAHs at this sampling site.

  5. Analysis of major air pollutants and submicron particles in New York City and Long Island

    Science.gov (United States)

    Masiol, M.; Hopke, P. K.; Felton, H. D.; Frank, B. P.; Rattigan, O. V.; Wurth, M. J.; LaDuke, G. H.

    2017-01-01

    A year-long sampling campaign of major air pollutants and submicron particle number size distributions was conducted at two sites taken as representative of city-wide air quality in New York City and Long Island, respectively. A number of species were quantified with hourly time resolution, including particle number concentrations in 6 size ranges (20-30 nm, 30-50 nm, 50-70 nm, 70-100 nm, 100-200 nm, and >200 nm), nitrogen oxides, sulfur dioxide, ozone, carbon monoxide, methane, non-methane hydrocarbons, PM2.5 mass concentration and some PM major components (sulfate, organic and elemental carbon). Hourly concentrations of primary and secondary organic carbon were estimated using the EC tracer method. Data were matched with weather parameters and air parcel back-trajectories. A series of tools were thus applied to: (i) study the seasonal, weekly, diurnal cycles of pollutants; (ii) investigate the relationships amongst pollutants through correlation and lagged correlation analyses; (iii) depict the role of atmospheric photochemical processes; (iv) examine the location of the potential sources by mean of conditional bivariate probability function analysis and (v) investigate the role of regional transport of air masses to the concentrations of analyzed species. Results indicate that concentrations of NOx, SO2, CO, non-methane hydrocarbons, primary OC and EC are predominantly determined by local sources, but are also affected by regional transports of polluted air masses. On the contrary, the transport of continental polluted air masses has a main effect in raising the concentrations of secondary PM2.5 (sulfate and secondary organic carbon). By providing direct information on the concentrations and trends of key pollutants and submicron particle number concentrations, this study finally enables some general considerations about air quality status and atmospheric processes over the New York City metropolitan area.

  6. Impact of agglomeration state of nano- and submicron sized gold particles on pulmonary inflammation

    Directory of Open Access Journals (Sweden)

    Cassee Flemming R

    2010-12-01

    Full Text Available Abstract Background Nanoparticle (NP toxicity testing comes with many challenges. Characterization of the test substance is of crucial importance and in the case of NPs, agglomeration/aggregation state in physiological media needs to be considered. In this study, we have addressed the effect of agglomerated versus single particle suspensions of nano- and submicron sized gold on the inflammatory response in the lung. Rats were exposed to a single dose of 1.6 mg/kg body weight (bw of spherical gold particles with geometric diameters of 50 nm or 250 nm diluted either by ultrapure water or by adding phosphate buffered saline (PBS. A single dose of 1.6 mg/kg bw DQ12 quartz was used as a positive control for pulmonary inflammation. Extensive characterization of the particle suspensions has been performed by determining the zetapotential, pH, gold concentration and particle size distribution. Primary particle size and particle purity has been verified using transmission electron microscopy (TEM techniques. Pulmonary inflammation (total cell number, differential cell count and pro-inflammatory cytokines, cell damage (total protein and albumin and cytotoxicity (alkaline phosphatase and lactate dehydrogenase were determined in bronchoalveolar lavage fluid (BALF and acute systemic effects in blood (total cell number, differential cell counts, fibrinogen and C-reactive protein 3 and 24 hours post exposure. Uptake of gold particles in alveolar macrophages has been determined by TEM. Results Particles diluted in ultrapure water are well dispersed, while agglomerates are formed when diluting in PBS. The particle size of the 50 nm particles was confirmed, while the 250 nm particles appear to be 200 nm using tracking analysis and 210 nm using TEM. No major differences in pulmonary and systemic toxicity markers were observed after instillation of agglomerated versus single gold particles of different sizes. Both agglomerated as well as single nanoparticles were

  7. A comparative study of submicron particle sizing platforms: accuracy, precision and resolution analysis of polydisperse particle size distributions.

    Science.gov (United States)

    Anderson, Will; Kozak, Darby; Coleman, Victoria A; Jämting, Åsa K; Trau, Matt

    2013-09-01

    The particle size distribution (PSD) of a polydisperse or multimodal system can often be difficult to obtain due to the inherent limitations in established measurement techniques. For this reason, the resolution, accuracy and precision of three new and one established, commercially available and fundamentally different particle size analysis platforms were compared by measuring both individual and a mixed sample of monodisperse, sub-micron (220, 330, and 410 nm - nominal modal size) polystyrene particles. The platforms compared were the qNano Tunable Resistive Pulse Sensor, Nanosight LM10 Particle Tracking Analysis System, the CPS Instruments's UHR24000 Disc Centrifuge, and the routinely used Malvern Zetasizer Nano ZS Dynamic Light Scattering system. All measurements were subjected to a peak detection algorithm so that the detected particle populations could be compared to 'reference' Transmission Electron Microscope measurements of the individual particle samples. Only the Tunable Resistive Pulse Sensor and Disc Centrifuge platforms provided the resolution required to resolve all three particle populations present in the mixed 'multimodal' particle sample. In contrast, the light scattering based Particle Tracking Analysis and Dynamic Light Scattering platforms were only able to detect a single population of particles corresponding to either the largest (410 nm) or smallest (220 nm) particles in the multimodal sample, respectively. When the particle sets were measured separately (monomodal) each platform was able to resolve and accurately obtain a mean particle size within 10% of the Transmission Electron Microscope reference values. However, the broadness of the PSD measured in the monomodal samples deviated greatly, with coefficients of variation being ~2-6-fold larger than the TEM measurements across all four platforms. The large variation in the PSDs obtained from these four, fundamentally different platforms, indicates that great care must still be taken in

  8. Formation of stable submicron peptide or protein particles by thin film freezing

    Energy Technology Data Exchange (ETDEWEB)

    Johnston, Keith P.; Engstrom, Joshua; Williams, III, Robert O.

    2017-04-18

    The present invention includes compositions and methods for preparing micron-sized or submicron-sized particles by dissolving a water soluble effective ingredient in one or more solvents; spraying or dripping droplets solvent such that the effective ingredient is exposed to a vapor-liquid interface of less than 50, 100, 150, 200, 250, 200, 400 or 500 cm.sup.-1 area/volume to, e.g., increase protein stability; and contacting the droplet with a freezing surface that has a temperature differential of at least 30.degree. C. between the droplet and the surface, wherein the surface freezes the droplet into a thin film with a thickness of less than 500 micrometers and a surface area to volume between 25 to 500 cm.sup.-1.

  9. Transmission Electron Microscopy Analysis of Submicronic Aerosol Particles Sampled at Jungfraujoch, Switzerland (CLACE-4)

    Science.gov (United States)

    Grobéty, B.; Lorenzo, R.

    2007-05-01

    Submicronic aerosol particles were collected in two sampling campaigns during CLACE-4 and -5 ("the Cloud and Aerosol Characterisation Experiment in the Free Troposphere") at the high alpine research station on top of Jungfraujoch (altitude: 3580 m.a.s.l.). The particles were deposited directly on transmission electron microscopy (TEM) grids placed in a home-made, calibrated thermophoretic sampling device. The samples were taken during periods of clear skies and temperatures below 0°C. Average sampling time was two days. The primary state of the particles was either solid, mixed solid-liquid or completely liquid. EDS spectra of solid particles without visible traces of a liquid coating contain only carbon and oxygen peaks. Mixed solid-fluid particles, however, have either carbon (C), mixed carbon-silicate (CS) or silicate (S) (probably SiO2) nuclei. The condensates remaining after evaporation of the liquid components contain sulfate (sulfur and oxygen peaks in EDS spectra), but no nitrate was found. The fraction > 500 nm is dominated by C and CS particles, the silicate particles have a narrow size distribution around 100 nm and contain, if at all, only faint sulfur peaks in their EDS spectra. The results are qualitatively consistent with analyses of samples collected during the same campaign (Weinbruch et al., 2005), but during mixed cloud events. There seem to be, however a differrence in the amount of particles with sulfate coatings, which is higher for samples taken under clear sky conditions. Weinbruch, S., Ebert, S., Worringen, A., and Brenker (2005), Identification of the ice forming fraction of the atmospheric aerosol in mixed-phase clouds by environmental scanning electron microscopy. Activity report 2005, International Foundation HFSJG.

  10. Bacterial characterization in ambient submicron particles during severe haze episodes at Ji'nan, China.

    Science.gov (United States)

    Xu, Caihong; Wei, Min; Chen, Jianmin; Wang, Xinfeng; Zhu, Chao; Li, Jiarong; Zheng, Lulu; Sui, Guodong; Li, Weijun; Wang, Wenxing; Zhang, Qingzhu; Mellouki, Abdelwahid

    2017-02-15

    In January 2014, severe haze episodes which sweep across Chinese cities have attracted public concern and interest at home and abroad. In addition to the physicochemical properties of air pollutants, bacteria are thought to be responsible for the spread of respiratory diseases and various allergies. We attempted the bacterial characterization of submicron particles (PM0.18-0.32, PM0.32-0.56, and PM0.56-1) under severe haze episodes using high-throughput sequencing and real-time quantitative PCR detecting system based on 21 samples collected from January to March 2014 at Ji'nan, China. The high bacterial concentration in PM0.32-0.56 (7314cells m(-3)), PM0.18-0.32 (7212cells m(-3)), and PM0.56-1 (6982cells m(-3)) showed significant negative correlations with SO2, NO2, and O3. Under sufficient sequencing depth, 37 phyla, 71 classes, 137 orders, 236 families, and 378 genera were classified, and the bacterial community structure varied significantly in different size fractions. For example, Holophagaceae (Acidobacteria) in PM0.32-0.56 showed 6-fold higher abundance than that in PM0.18-0.32. Moreover, functional categories and bacterial species (Lactococcus piscium, Pseudomonas fragi, Streptococcus agalactiae, and Pseudomonas cichorii) that may potentially be responsible for infections and allergies were also discovered. Source track analysis showed that the ambient bacteria mainly originated from soils, leaf surfaces, and feces. Our results highlighted the importance of airborne microbial communities by understanding the concentration, structure, ecological and health effects, especially those in submicron particles during haze episodes.

  11. Indomethacin submicron particle capsules provide effective pain relief in patients with acute pain: a phase 3 study.

    Science.gov (United States)

    Altman, Roy; Daniels, Stephen; Young, Clarence L

    2013-11-01

    Although frequently prescribed to relieve acute pain in patients, non-steroidal anti-inflammatory drugs (NSAIDs) are associated with dose-related gastrointestinal, cardiovascular, and renal complications. Investigational, submicron particle NSAIDs are being developed that could provide effective pain relief at lower doses than currently available oral NSAIDs. This is the first phase 3 study evaluating the analgesic efficacy and safety of lower-dose indomethacin submicron particle capsules in patients following elective surgery. This multicenter, double-blind study enrolled patients aged 18 to 68 years who underwent bunionectomy under regional anesthesia. Patients with a pain intensity rating of ≥40 mm on a 100-mm Visual Analog Scale were randomized to receive indomethacin submicron particle capsules (40 mg 3 times daily [TID], 40 mg twice daily [BID], or 20 mg TID), celecoxib (400 mg loading dose, then 200 mg BID), or placebo. The primary efficacy parameter was the overall (summed) pain intensity difference measured by a Visual Analog Scale during a period of 48 hours. Scheduled assessments measured secondary efficacy parameters such as patient pain intensity differences. Indomethacin submicron particle capsules 40 mg 3 times daily (509.6 ± 91.9 overall [summed] pain intensity difference), 40 mg twice daily (328.0 ± 92.9 overall [summed] pain intensity difference), and 20 mg 3 times daily (380.5 ± 92.9 overall [summed] pain intensity difference) reduced pain intensity from 0 to 48 hours (P ≤ 0.046 for all 3 groups) compared with placebo (67.8 ± 91.4 overall [summed] pain intensity difference). There was some evidence of patient analgesia for celecoxib (279.4 ± 91.9 overall [summed] pain intensity difference; P = 0.103). Some evidence of pain control was observed in patients as early as 2 hours following administration of indomethacin submicron particle capsules and was sustained throughout the treatment period. Indomethacin submicron particle capsules were

  12. A phase 2 study of lower-dose, indomethacin submicron particle capsules demonstrates early onset of acute pain relief.

    Science.gov (United States)

    Manvelian, Garen; Hochberg, Marc C; Daniels, Stephen E; Altman, Roy D; Young, Clarence L

    2014-10-01

    Nonsteroidal anti-inflammatory drugs are efficacious for the treatment of acute and chronic pain; however, they have the potential for serious adverse events (AEs). The objective of this study was to evaluate the efficacy and safety of investigational, lower-dose, indomethacin submicron particle capsules compared with placebo in a study of patients with postsurgical pain. This phase 2, multicenter, randomized, double-blind, single-dose, and placebo-controlled study enrolled 203 patients (18 to 50 y old) following extraction of ≥ 2 third molars who experienced moderate-to-severe pain intensity ≤ 6 hours after surgery. Patients received indomethacin submicron particle capsules (20 or 40 mg), celecoxib 400 mg, or placebo. The primary efficacy endpoint was the sum of total pain relief over 0 to 8 hours (TOTPAR-8) determined from the area under the curve for pain relief over 0 to 8 hours following administration of the study drug, where pain relief was measured on a 0 to 4 scale. Safety and tolerability were also assessed. Mean ± SE TOTPAR-8 scores were 10.8 ± 1.4 (indomethacin submicron particle capsules 20 mg), 12.6 ± 1.3 (indomethacin submicron particle capsules 40 mg), 14.8 ± 1.3 (celecoxib), and 3.0 ± 1.3 (placebo; Pcapsules treatment groups demonstrated better mean TOTPAR over 4 hours than placebo (Pcapsules provide good overall pain relief in patients with postsurgical pain and are generally well tolerated. Indomethacin submicron particle capsules are a potentially promising option for treatment of acute pain and warrant further study.

  13. Simulation on a novel micron-array inertial impactor for submicron and ultrafine particle separation

    Science.gov (United States)

    Liu, Rui-Tao; Tao, Lu-Qi; Yang, Yi; Ren, Tian-Ling

    2016-08-01

    The particulate matter (PM), which was put forward in 1997 by US, had taken more and more attention due to the influence on human health. Although the mass concentration, number concentration and chemical composition of PM were still major research directions, how to collect these PMs more efficiently becomes critical. Inertial impactor is an effective separation device, however, due to different motion states of PM2.5 and PM0.3 in the flow field, the inertial impactor which can separate PM0.3 from other PMs has not been fabricated. In this work, the motion states for both submicron and ultrafine particles were studied by using classical theory of channel aerodynamic, and a novel micron-array inertial impactor was designed and simulated for the first time. Besides, the influence of some characteristic parameters (W, T, S, Dc, etc.) on particle collection efficiency were researched and discussed through simulation results. This novel structure can be easily fabricated by MEMS technology or laser direct writing and also can be widely used in particle separation or flexible sensor fields.

  14. Size-Dependent Photodynamic Anticancer Activity of Biocompatible Multifunctional Magnetic Submicron Particles in Prostate Cancer Cells

    Directory of Open Access Journals (Sweden)

    Kyong-Hoon Choi

    2016-09-01

    Full Text Available In this study, newly designed biocompatible multifunctional magnetic submicron particles (CoFe2O4-HPs-FAs of well-defined sizes (60, 133, 245, and 335 nm were fabricated for application as a photosensitizer delivery agent for photodynamic therapy in cancer cells. To provide selective targeting of cancer cells and destruction of cancer cell functionality, basic cobalt ferrite (CoFe2O4 particles were covalently bonded with a photosensitizer (PS, which comprises hematoporphyrin (HP, and folic acid (FA molecules. The magnetic properties of the CoFe2O4 particles were finely adjusted by controlling the size of the primary CoFe2O4 nanograins, and secondary superstructured composite particles were formed by aggregation of the nanograins. The prepared CoFe2O4-HP-FA exhibited high water solubility, good MR-imaging capacity, and biocompatibility without any in vitro cytotoxicity. In particular, our CoFe2O4-HP-FA exhibited remarkable photodynamic anticancer efficiency via induction of apoptotic death in PC-3 prostate cancer cells in a particle size- and concentration-dependent manner. This size-dependent effect was determined by the specific surface area of the particles because the number of HP molecules increased with decreasing size and increasing surface area. These results indicate that our CoFe2O4-HP-FA may be applicable for photodynamic therapy (PDT as a PS delivery material and a therapeutic agent for MR-imaging based PDT owing to their high saturation value for magnetization and superparamagnetism.

  15. Reactivity of chlorine radical with submicron palmitic acid particles: kinetic measurements and products identification

    Directory of Open Access Journals (Sweden)

    M. Mendez

    2013-06-01

    Full Text Available The heterogeneous reaction of Cl. radicals with sub-micron palmitic acid (PA particles was studied in an aerosol flow tube in the presence or in the absence of O2. Fine particles were generated by homogeneous condensation of PA vapors and introduced in the reactor where chlorine atoms are produced by photolysis of Cl2 using UV lamps surrounding the reactor. The effective reactive uptake coefficient (γ has been determined from the rate loss of PA measured by GC/MS analysis of reacted particles as a function of the chlorine exposure. In the absence of O2, γ = 14 ± 5 indicates efficient secondary chemistry involving Cl2. GC/MS analyses have shown the formation of monochlorinated and polychlorinated compounds in the oxidized particles. Although, the PA particles are solid, the complete mass can be consumed. In the presence of oxygen, the reaction is still dominated by secondary chemistry but the propagation chain length is smaller than in the absence of O2 which leads to an uptake coefficient γ = 3 ± 1. In the particulate phase, oxocarboxylic acids and dicarboxylic acids are identified by GC/MS. Formation of alcohols and monocarboxylic acids are also suspected. All these results show that solid organic particles could be efficiently oxidized by gas-phase radicals not only on their surface, but also in bulk by mechanisms which are still unclear. Furthermore the identified reaction products are explained by a chemical mechanism showing the pathway of the formation of more functionalized products. They help to understand the aging of primary tropospheric aerosol containing fatty acids.

  16. Reactivity of chlorine radical with submicron palmitic acid particles: kinetic measurements and product identification

    Science.gov (United States)

    Mendez, M.; Ciuraru, R.; Gosselin, S.; Batut, S.; Visez, N.; Petitprez, D.

    2013-12-01

    The heterogeneous reaction of Cl• radicals with submicron palmitic acid (PA) particles was studied in an aerosol flow tube in the presence or in the absence of O2. Fine particles were generated by homogeneous condensation of PA vapours and introduced into the reactor, where chlorine atoms were produced by photolysis of Cl2 using UV lamps surrounding the reactor. The effective reactive uptake coefficient (γ) has been determined from the rate loss of PA measured by gas chromatography-mass spectrometer (GC/MS) analysis of reacted particles as a function of the chlorine exposure. In the absence of O2, γ = 14 ± 5 indicates efficient secondary chemistry involving Cl2. GC/MS analysis has shown the formation of monochlorinated and polychlorinated compounds in the oxidized particles. Although the PA particles are solid, the complete mass can be consumed. In the presence of oxygen, the reaction is still dominated by secondary chemistry but the propagation chain length is smaller than in the absence of O2, which leads to an uptake coefficient γ = 3 ± 1. In the particulate phase, oxocarboxylic acids and dicarboxylic acids were identified by GC/MS. The formation of alcohols and monocarboxylic acids is also suspected. A reaction pathway for the main products and more functionalized species is proposed. All these results show that solid organic particles could be efficiently oxidized by gas-phase radicals not only on their surface but also in bulk by mechanisms which are still unclear. They help to understand the aging of primary tropospheric aerosol containing fatty acids.

  17. Reactivity of chlorine radical with submicron palmitic acid particles: kinetic measurements and products identification

    Science.gov (United States)

    Mendez, M.; Ciuraru, R.; Gosselin, S.; Batut, S.; Visez, N.; Petitprez, D.

    2013-06-01

    The heterogeneous reaction of Cl. radicals with sub-micron palmitic acid (PA) particles was studied in an aerosol flow tube in the presence or in the absence of O2. Fine particles were generated by homogeneous condensation of PA vapors and introduced in the reactor where chlorine atoms are produced by photolysis of Cl2 using UV lamps surrounding the reactor. The effective reactive uptake coefficient (γ) has been determined from the rate loss of PA measured by GC/MS analysis of reacted particles as a function of the chlorine exposure. In the absence of O2, γ = 14 ± 5 indicates efficient secondary chemistry involving Cl2. GC/MS analyses have shown the formation of monochlorinated and polychlorinated compounds in the oxidized particles. Although, the PA particles are solid, the complete mass can be consumed. In the presence of oxygen, the reaction is still dominated by secondary chemistry but the propagation chain length is smaller than in the absence of O2 which leads to an uptake coefficient γ = 3 ± 1. In the particulate phase, oxocarboxylic acids and dicarboxylic acids are identified by GC/MS. Formation of alcohols and monocarboxylic acids are also suspected. All these results show that solid organic particles could be efficiently oxidized by gas-phase radicals not only on their surface, but also in bulk by mechanisms which are still unclear. Furthermore the identified reaction products are explained by a chemical mechanism showing the pathway of the formation of more functionalized products. They help to understand the aging of primary tropospheric aerosol containing fatty acids.

  18. The role of adsorbed water on the friction of a layer of submicron particles

    Science.gov (United States)

    Sammis, Charles G.; Lockner, David A.; Reches, Ze’ev

    2011-01-01

    Anomalously low values of friction observed in layers of submicron particles deformed in simple shear at high slip velocities are explained as the consequence of a one nanometer thick layer of water adsorbed on the particles. The observed transition from normal friction with an apparent coefficient near μ = 0.6 at low slip speeds to a coefficient near μ = 0.3 at higher slip speeds is attributed to competition between the time required to extrude the water layer from between neighboring particles in a force chain and the average lifetime of the chain. At low slip speeds the time required for extrusion is less than the average lifetime of a chain so the particles make contact and lock. As slip speed increases, the average lifetime of a chain decreases until it is less than the extrusion time and the particles in a force chain never come into direct contact. If the adsorbed water layer enables the otherwise rough particles to rotate, the coefficient of friction will drop to μ = 0.3, appropriate for rotating spheres. At the highest slip speeds particle temperatures rise above 100°C, the water layer vaporizes, the particles contact and lock, and the coefficient of friction rises to μ = 0.6. The observed onset of weakening at slip speeds near 0.001 m/s is consistent with the measured viscosity of a 1 nm thick layer of adsorbed water, with a minimum particle radius of approximately 20 nm, and with reasonable assumptions about the distribution of force chains guided by experimental observation. The reduction of friction and the range of velocities over which it occurs decrease with increasing normal stress, as predicted by the model. Moreover, the analysis predicts that this high-speed weakening mechanism should operate only for particles with radii smaller than approximately 1 μm. For larger particles the slip speed required for weakening is so large that frictional heating will evaporate the adsorbed water and weakening will not occur.

  19. Number size distributions and seasonality of submicron particles in Europe 2008–2009

    Directory of Open Access Journals (Sweden)

    A. Asmi

    2011-06-01

    Full Text Available Two years of harmonized aerosol number size distribution data from 24 European field monitoring sites have been analysed. The results give a comprehensive overview of the European near surface aerosol particle number concentrations and number size distributions between 30 and 500 nm of dry particle diameter. Spatial and temporal distribution of aerosols in the particle sizes most important for climate applications are presented. We also analyse the annual, weekly and diurnal cycles of the aerosol number concentrations, provide log-normal fitting parameters for median number size distributions, and give guidance notes for data users. Emphasis is placed on the usability of results within the aerosol modelling community.

    We also show that the aerosol number concentrations of Aitken and accumulation mode particles (with 100 nm dry diameter as a cut-off between modes are related, although there is significant variation in the ratios of the modal number concentrations. Different aerosol and station types are distinguished from this data and this methodology has potential for further categorization of stations aerosol number size distribution types.

    The European submicron aerosol was divided into characteristic types: Central European aerosol, characterized by single mode median size distributions, unimodal number concentration histograms and low variability in CCN-sized aerosol number concentrations; Nordic aerosol with low number concentrations, although showing pronounced seasonal variation of especially Aitken mode particles; Mountain sites (altitude over 1000 m a.s.l. with a strong seasonal cycle in aerosol number concentrations, high variability, and very low median number concentrations. Southern and Western European regions had fewer stations, which decreases the regional coverage of these results. Aerosol number concentrations over the Britain and Ireland had very high variance and there are indications of mixed air masses

  20. Measurements of Submicron Particle Adsorption and Particle Film Elasticity at Oil-Water Interfaces.

    Science.gov (United States)

    Manga, Mohamed S; Hunter, Timothy N; Cayre, Olivier J; York, David W; Reichert, Matthew D; Anna, Shelly L; Walker, Lynn M; Williams, Richard A; Biggs, Simon R

    2016-05-01

    The influence of particle adsorption on liquid/liquid interfacial tension is not well understood, and much previous research has suggested conflicting behaviors. In this paper we investigate the surface activity and adsorption kinetics of charge stabilized and pH-responsive polymer stabilized colloids at oil/water interfaces using two tensiometry techniques: (i) pendant drop and (ii) microtensiometer. We found, using both techniques, that charge stabilized particles had little or no influence on the (dynamic) interfacial tension, although dense silica particles affected the "apparent" measured tension in the pendent drop, due to gravity driven elongation of the droplet profile. Nevertheless, this apparent change additionally allowed the study of adsorption kinetics, which was related qualitatively between particle systems by estimated diffusion coefficients. Significant and real interfacial tension responses were measured using ∼53 nm core-shell latex particles with a pH-responsive polymer stabilizer of poly(methyl methacrylate)-b-poly(2-(dimethylamino)ethyl methacrylate) (pMMA-b-pDMAEMA) diblock copolymer. At pH 2, where the polymer is strongly charged, behavior was similar to that of the bare charge-stabilized particles, showing little change in the interfacial tension. At pH 10, where the polymer is discharged and poorly soluble in water, a significant decrease in the measured interfacial tension commensurate with strong adsorption at the oil-water interface was seen, which was similar in magnitude to the surface activity of the free polymer. These results were both confirmed through droplet profile and microtensiometry experiments. Dilational elasticity measurements were also performed by oscillation of the droplet; again, changes in interfacial tension with droplet oscillation were only seen with the responsive particles at pH 10. Frequency sweeps were performed to ascertain the dilational elasticity modulus, with measured values being significantly higher

  1. Electric filed induced self-assembly of monolayers of sub-micron sized particles on flexible thin films

    Science.gov (United States)

    Shah, K.; Hossain, M.; Janjua, M.; Aubry, N.; Fischer, I. S.; Singh, P.

    2013-11-01

    We present a technique that uses an electric field in the direction normal to the interface for self-assembling particle monolayers of sub-micron sized particles on fluid-liquid interfaces and freezing these monolayers onto the surface of a flexible thin film. The electric field gives rise to dipole-dipole and capillary forces which cause the particles to arrange in a triangular pattern. The technique involves assembling the monolayer on the interface between a UV-curable resin and another fluid by applying an electric field, and then curing the resin by applying UV light. The monolayer becomes embedded on the surface of the solidified resin film.

  2. Atmospheric Chemistry Special Feature: Carbohydrate-like composition of submicron atmospheric particles and their production from ocean bubble bursting

    Science.gov (United States)

    Russell, Lynn M.; Hawkins, Lelia N.; Frossard, Amanda A.; Quinn, Patricia K.; Bates, Tim S.

    2010-04-01

    Oceans cover over two-thirds of the Earth's surface, and the particles emitted to the atmosphere by waves breaking on sea surfaces provide an important contribution to the planetary albedo. During the International Chemistry Experiment in the Arctic LOwer Troposphere (ICEALOT) cruise on the R/V Knorr in March and April of 2008, organic mass accounted for 15-47% of the submicron particle mass in the air masses sampled over the North Atlantic and Arctic Oceans. A majority of this organic component (0.1 - 0.4 μ m-3) consisted of organic hydroxyl (including polyol and other alcohol) groups characteristic of saccharides, similar to biogenic carbohydrates found in seawater. The large fraction of organic hydroxyl groups measured during ICEALOT in submicron atmospheric aerosol exceeded those measured in most previous campaigns but were similar to particles in marine air masses in the open ocean (Southeast Pacific Ocean) and coastal sites at northern Alaska (Barrow) and northeastern North America (Appledore Island and Chebogue Point). The ocean-derived organic hydroxyl mass concentration during ICEALOT correlated strongly to submicron Na concentration and wind speed. The observed submicron particle ratios of marine organic mass to Na were enriched by factors of ˜102-˜103 over reported sea surface organic to Na ratios, suggesting that the surface-controlled process of film bursting is influenced by the dissolved organic components present in the sea surface microlayer. Both marine organic components and Na increased with increasing number mean diameter of the accumulation mode, suggesting a possible link between organic components in the ocean surface and aerosol-cloud interactions.

  3. Neurotoxicity of low-dose repeatedly intranasal instillation of nano- and submicron-sized ferric oxide particles in mice

    Science.gov (United States)

    Wang, Bing; Feng, Weiyue; Zhu, Motao; Wang, Yun; Wang, Meng; Gu, Yiqun; Ouyang, Hong; Wang, Huajian; Li, Ming; Zhao, Yuliang; Chai, Zhifang; Wang, Haifang

    2009-01-01

    Olfactory tract has been demonstrated to be an important portal for inhaled solid nanoparticle transportation into the central nervous system (CNS). We have previously demonstrated that intranasally instilled Fe2O3 nanoparticles could transport into the CNS via olfactory pathway. In this study, we investigated the neurotoxicity and size effect of repeatedly low-dose (130 μg) intranasal exposure of nano- and submicron-sized Fe2O3 particles (21 nm and 280 nm) to mice. The biomarkers of oxidative stress, activity of nitric oxide synthases and release of monoamine neurotransmitter in the brain were studied. Our results showed that significant oxidative stress was induced by the two sizes of Fe2O3 particles. The activities of GSH-Px, Cu,Zn-SOD, and cNOS significantly elevated and the total GSH and GSH/GSSG ratio significantly decreased in the olfactory bulb and hippocampus after the nano- and submicron-sized Fe2O3 particle treatment ( p < 0.05). The nano-sized Fe2O3 generally induced greater alteration and more significant dose-effect response than the submicron-sized particle did. Some slight perturbation of monoamine neurotransmitters were found in the hippocampus after exposure to the two sizes of Fe2O3 particle. The TEM image showed that some ultrastructural alterations in nerve cells, including neurodendron degeneration, membranous structure disruption and lysosome increase in the olfactory bulb, slight dilation in the rough endoplasmic reticulum and lysosome increase in the hippocampus were induced by the nano-sized Fe2O3 treatment. In contrast, in the submicron-sized Fe2O3 treated mice, slightly swollen mitochondria and some vacuoles were observed in the olfactory bulb and hippocampus, respectively. These results indicate that intranasal exposure of Fe2O3 nanoparticles could induce more severe oxidative stress and nerve cell damage in the brain than the larger particle did. This is the first study to compare the neurotoxicity of nano- and submicron-sized Fe2O3

  4. Neurotoxicity of low-dose repeatedly intranasal instillation of nano- and submicron-sized ferric oxide particles in mice

    Energy Technology Data Exchange (ETDEWEB)

    Wang Bing; Feng Weiyue, E-mail: fengwy@mail.ihep.ac.cn; Zhu Motao; Wang Yun; Wang Meng [Chinese Academy of Sciences, Laboratory for Bio-Environmental Effects of Nanomaterials and Nanosafety and Key Laboratory of Nuclear Analytical Techniques, Institute of High Energy Physics (China); Gu Yiqun [Maternity Hospital of Haidian District (China); Ouyang Hong; Wang Huajian; Li Ming; Zhao Yuliang, E-mail: zhaoyuliang@mail.ihep.ac.cn; Chai Zhifang [Chinese Academy of Sciences, Laboratory for Bio-Environmental Effects of Nanomaterials and Nanosafety and Key Laboratory of Nuclear Analytical Techniques, Institute of High Energy Physics (China); Wang Haifang [Peking University, College of Chemistry and Molecular Engineering (China)

    2009-01-15

    Olfactory tract has been demonstrated to be an important portal for inhaled solid nanoparticle transportation into the central nervous system (CNS). We have previously demonstrated that intranasally instilled Fe{sub 2}O{sub 3} nanoparticles could transport into the CNS via olfactory pathway. In this study, we investigated the neurotoxicity and size effect of repeatedly low-dose (130 {mu}g) intranasal exposure of nano- and submicron-sized Fe{sub 2}O{sub 3} particles (21 nm and 280 nm) to mice. The biomarkers of oxidative stress, activity of nitric oxide synthases and release of monoamine neurotransmitter in the brain were studied. Our results showed that significant oxidative stress was induced by the two sizes of Fe{sub 2}O{sub 3} particles. The activities of GSH-Px, Cu,Zn-SOD, and cNOS significantly elevated and the total GSH and GSH/GSSG ratio significantly decreased in the olfactory bulb and hippocampus after the nano- and submicron-sized Fe{sub 2}O{sub 3} particle treatment (p < 0.05). The nano-sized Fe{sub 2}O{sub 3} generally induced greater alteration and more significant dose-effect response than the submicron-sized particle did. Some slight perturbation of monoamine neurotransmitters were found in the hippocampus after exposure to the two sizes of Fe{sub 2}O{sub 3} particle. The TEM image showed that some ultrastructural alterations in nerve cells, including neurodendron degeneration, membranous structure disruption and lysosome increase in the olfactory bulb, slight dilation in the rough endoplasmic reticulum and lysosome increase in the hippocampus were induced by the nano-sized Fe{sub 2}O{sub 3} treatment. In contrast, in the submicron-sized Fe{sub 2}O{sub 3} treated mice, slightly swollen mitochondria and some vacuoles were observed in the olfactory bulb and hippocampus, respectively. These results indicate that intranasal exposure of Fe{sub 2}O{sub 3} nanoparticles could induce more severe oxidative stress and nerve cell damage in the brain than the

  5. Submicron Particles during Macro- and Micro-Weldings Procedures in Industrial Indoor Environments and Health Implications for Welding Operators

    Directory of Open Access Journals (Sweden)

    Pasquale Avino

    2015-06-01

    Full Text Available One of the emerging risks in the engineering and electronic industries is the exposure of workers to ultrafine particles during (micro-welding operations, i.e., processes used for joining two metal parts heated locally, which constitute the base metal, with or without addition of another metal which is the filler metal, melted between the edges to be joined. The process is accompanied by formation of metallic fumes arising from the molten metal as well as by the emission of metal fumes of variable composition depending on the alloys welded and fused. The aim of this paper is to investigate the number, concentration and size distribution of submicron particles produced by (micro-welding processes. Particle number size distribution is continuously measured during (micro-welding operations by means of two instruments, i.e., Fast Mobility Particle Sizer and Nanoparticle Surface Area Monitor. The temporal variation of the particle number size distribution across the peaks evidences the strong and fast-evolving contribution of nucleation mode particles: peak values are maintained for less than 10 s. The implication of such contribution on human health is linked to the high deposition efficiency of submicronic particles in the alveolar interstitial region of the human respiratory system, where gas exchange occurs.

  6. Seasonality of ultrafine and sub-micron aerosols and the inferences on particle formation processes

    Science.gov (United States)

    Cheung, H. C.; Chou, C. C.-K.; Chen, M.-J.; Huang, W.-R.; Huang, S.-H.; Tsai, C.-Y.; Lee, C. S.-L.

    2015-08-01

    The aim of this study is to investigate the seasonal variations in the physicochemical properties of atmospheric ultrafine particles (UFPs, d ≤ 100nm) and submicron particles (PM1, d ≤ 1 μm) in an East-Asian urban area, which are hypothesized to be affected by the interchange of summer and winter monsoons. An observation experiment was conducted at the TARO, an urban aerosol station in Taipei, Taiwan, from October 2012 to August 2013. The measurements included the mass concentration and chemical composition of UFPs and PM1, as well as the particle number concentration (PNC) and size distribution (PSD) with size range of 4-736 nm. The results indicate that the mass concentration of PM1 was elevated during cold seasons with peak level of 18.5 μg m-3 in spring, whereas the highest UFPs concentration was measured in summertime with a seasonal mean of 1.62 μg m-3. Moreover, chemical analysis revealed that the UFPs and PM1 were characterized by distinct composition; UFPs were composed mostly of organics, whereas ammonium and sulfate were the major constituents in PM1. The seasonal median of total PNCs ranged from 13.9 × 103 cm-3 in autumn to 19.4 × 103 cm-3 in spring. The PSD information retrieved from the corresponding PNC measurements indicates that the nucleation mode PNC (N4-25) peaked at 11.6 × 103 cm-3 in winter, whereas the Aitken mode (N25-100) and accumulation mode (N100-736) exhibited summer maxima at 6.0 × 103 and 3.1 × 103 cm-3, respectively. The shift in PSD during summertime is attributed to the enhancement in the photochemical production of condensable organic matter that, in turn, contributes to the growth of aerosol particles in the atmosphere. In addition, remarkable photochemical production of particles was observed in spring and summer seasons, which was characterized with averaged particle growth and formation rates of 4.3 ± 0.8 nm h-1 and 1.6 ± 0.8 cm-3 s-1, respectively. The prevalence of new particle formation (NPF) in summer is

  7. Surface modification of submicronic TiO{sub 2} particles prepared by ultrasonic spray pyrolysis for visible light absorption

    Energy Technology Data Exchange (ETDEWEB)

    Dugandzic, Ivan M. [Institute of Technical Sciences of SASA (Serbia); Jovanovic, Dragana J. [University of Belgrade, Vinca Institute of Nuclear Sciences (Serbia); Mancic, Lidija T. [Institute of Technical Sciences of SASA (Serbia); Zheng, Nan; Ahrenkiel, Scott P. [South Dakota School of Mines and Technology (United States); Milosevic, Olivera B. [Institute of Technical Sciences of SASA (Serbia); Saponjic, Zoran V.; Nedeljkovic, Jovan M., E-mail: jovned@vinca.rs [University of Belgrade, Vinca Institute of Nuclear Sciences (Serbia)

    2012-10-15

    Spherical, submicronic TiO{sub 2} assemblage with high specific surface area and controllable phase composition was prepared in the process of ultrasonic spray drying/pyrolysis in a wide temperature range (150-800 Degree-Sign C) by using as a precursor aqueous colloidal solution consisting of TiO{sub 2} nanoparticles (4.5 nm). Submicronic, soft and grained spherical TiO{sub 2} particles (d = 370-500 nm) comprising clustered nanocrystals (<10 nm) were obtained at low processing temperature, while particle densification, intensive growth of the clustered primary units and anatase-to-rutile transformation ({approx}30 wt%) were observed at the higher temperatures. Detailed structural and morphological characterisation were performed by X-ray powder diffraction, scanning and field emission electron microscopy, transmission electron microscopy, and laser particle size analysis. Moreover, the surface modification of TiO{sub 2} particles through the formation of charge-transfer (CT) complex was achieved with different ligands: ascorbic acid, dopamine, catechol, 2,3-dihydroxynaphthalene, and anthrarobin. Optical properties of the surface-modified TiO{sub 2} particles were studied by using diffuse reflection spectroscopy. The binding structure between the surface titanium atoms and different ligands was determined by using Fourier transform infrared spectroscopy. The formation of CT complexes induced significant red shift of optical absorption in comparison to unmodified TiO{sub 2} particles.

  8. Long-term Chemical Characterization of Submicron Aerosol Particles in the Amazon Forest - ATTO Station

    Science.gov (United States)

    Carbone, S.; Brito, J.; Rizzo, L. V.; Holanda, B. A.; Cirino, G. G.; Saturno, J.; Krüger, M. L.; Pöhlker, C.; Ng, N. L.; Xu, L.; Andreae, M. O.; Artaxo, P.

    2015-12-01

    The study of the chemical composition of aerosol particles in the Amazon forest represents a step forward to understand the strong coupling between the atmosphere and the forest. For this reason submicron aerosol particles were investigated in the Amazon forest, where biogenic and anthropogenic aerosol particles coexist at the different seasons (wet/dry). The measurements were performed at the ATTO station, which is located about 150 km northeast of Manaus. At ATTO station the Aerosol chemical speciation monitor (ACSM, Aerodyne) and the Multiangle absorption photometer (MAAP, Thermo 5012) have been operated continuously from March 2014 to July 2015. In this study, long-term measurements (near-real-time, ~30 minutes) of PM1 chemical composition were investigated for the first time in this environment.The wet season presented lower concentrations than the dry season (~5 times). In terms of chemical composition, both seasons were dominated by organics (75 and 63%) followed by sulfate (11 and 13%). Nitrate presented different ratio values between the mass-to-charges 30 to 46 (main nitrate fragments) suggesting the presence of nitrate as inorganic and organic nitrate during both seasons. The results indicated that about 75% of the nitrate signal was from organic nitrate during the dry season. In addition, several episodes with elevated amount of chloride, likely in the form of sea-salt from the Atlantic Ocean, were observed during the wet season. During those episodes, chloride comprised up to 7% of the PM1. During the dry season, chloride was also observed; however, with different volatility, which suggested that Chloride was present in different form and source. Moreover, the constant presence of sulfate and BC during the wet season might be related to biomass burning emissions from Africa. BC concentration was 2.5 times higher during the dry season. Further characterization of the organic fraction was accomplished with the positive matrix factorization (PMF), which

  9. Design of lipid matrix particles for fenofibrate

    DEFF Research Database (Denmark)

    Xia, Dengning; Cui, Fude; Gan, Yong

    2014-01-01

    The effect of polymorphism of glycerol monostearate (GMS) on drug incorporation and release from lipid matrix particles (LMPs) was investigated using fenofibrate as a model drug. X-ray powder diffraction and differential scanning calorimetry were used to study the polymorphism change of GMS and t...

  10. Heated submicron particle fluxes using an optical particle counter in urban environment

    Science.gov (United States)

    Vogt, M.; Johansson, C.; Mårtensson, M.; Struthers, H.; Ahlm, L.; Nilsson, D.

    2013-03-01

    From May 2008 to March 2009 aerosol emissions were measured using the eddy covariance method covering the size range 0.25 to 2.5 μm diameter (Dp) from a 105 m tower, in central Stockholm, Sweden. Supporting chemical aerosol data were collected at roof and street level. Results show that the inorganic fraction of sulfate, nitrate, ammonium and sea salt accounts for approximately 15% of the total aerosol mass traffic (as inferred from the ratio of the incremental concentrations of nitrogen oxides (NOx) and BC measured on a densely trafficked street) and the fluxes of non-volatile material at tower level are in close agreement, suggesting a traffic source of BC. We have estimated the emission factors (EFs) for non-volatile particles traffic activity data. Light (LDV) and heavy duty vehicle (HDV) EFs were estimated using multiple linear regression and reveal that for non-volatile particulate matter in the 0.25 to 0.6 μm Dp range, the EFHDV is approximately twice as high as the EFLDV, the difference not being statistically significant.

  11. Reduced Burst Release and Enhanced Oral Bioavailability in Shikimic Acid-Loaded Polylactic Acid Submicron Particles by Coaxial Electrospray.

    Science.gov (United States)

    Wang, Miaomiao; Wang, Yuanwen; Omari-Siaw, Emmanuel; Wang, Shengli; Zhu, Yuan; Xu, Ximing

    2016-08-01

    In this study, using the coaxial electrospray method, we prepared submicron particles of the water-soluble drug shikimic acid (SA) with polylactic acid (PLA) as a polymer, to reduce the burst release and enhance the oral bioavailability. In vitro release study performed in HCl solution (pH 1.2) showed that the coaxial electrospray submicron particles could reduce burst release effect and presented a sustained release profile, compared with free SA and the particles prepared by electrospray method. The absorption of SA in the intestinal tract, studied using an in situ perfusion method in rats, also revealed jejunum as the main absorptive segment followed by duodenum and ileum. Moreover, the SA-loaded particles greatly enhanced the absorption of SA in the tested intestinal segments. The intestinal absorption rate was not enhanced with increasing drug concentration (5-15 μg/mL) which suggested that active transport or facilitated diffusion could play vital role in SA absorption. In addition, the SA-loaded PLA coaxial electrospray particle exhibited a prolonged plasma circulation with enhanced bioavailability after oral administration. In all, the coaxial electrospray technique could provide notable advantages for the oral delivery of SA, thereby enhancing its clinical application.

  12. Synthesis of submicron-sized peanut-shaped poly(methyl methacrylate)/polystyrene particles by seeded soap-free emulsion polymerization

    Institute of Scientific and Technical Information of China (English)

    Shan Shi; Tao Wang; Yan Tao Tang; Li Min Zhou; Shin Ichi Kuroda

    2011-01-01

    Submicron-sized peanut-shaped poly(methyl methacrylate)/polystyrene (PMMA/PS) particles were successfully synthesized by seeded soap-free emulsion polymerization of styrene on the spherical crosslinked PMMA seed particles. The obtained peanut-shaped particles showed a novel internal morphology: PS phase formed one domain which linked to the other domain having PMMA core encased by PS shell.

  13. Submicron polymeric particles prepared by vibrational spray-drying: Semisolid formulation and skin penetration/permeation studies.

    Science.gov (United States)

    Beber, T C; Andrade, D F; Kann, B; Fontana, M C; Coradini, K; Windbergs, M; Beck, R C R

    2014-11-01

    Topical glucocorticoids (TG) such as dexamethasone (DEX) have been used for decades for the treatment of skin diseases. However, TG present well-documented side effects and their delivery to the skin is often insufficient. Therefore, many efforts have been undergone to improve the amount of drug delivered to the skin and to reduce side effects at the same time. In this work, the feasibility of DEX-submicron polymeric particles (SP) prepared by vibrational spray-drying as an approach to overcome the challenges associated with the topical administration of this drug class was evaluated. DEX was homogeneously dispersed in the SP matrix, according to confocal Raman microscopy analysis. Drug-loaded SP were incorporated into the oil phase of oil-in-water emulsions (creams). The formulation containing polymeric submicron particles (C-SP) showed controlled drug release kinetics and a significant drug accumulation in skin compared to formulations containing non-polymeric particles or free drug. DEX accumulation in the stratum corneum was evaluated by tape stripping and a depot effect over time was observed for C-SP, while the formulation containing the free drug showed a decrease over time. Similarly, C-SP presented higher drug retention in epidermis and dermis in skin penetration studies performed on pig skin in Franz diffusion cells, while drug permeation into the receptor compartment was negligible. It was demonstrated, for the first time, the advantageous application of submicron polymeric particles obtained by vibrational spray-drying in semisolid formulations for cutaneous administration to overcome challenges related to the therapy with TG such as DEX.

  14. Enhanced sub-micron colloidal particle separation with interdigitated microelectrode arrays using mixed AC/DC dielectrophoretic scheme.

    Science.gov (United States)

    Swaminathan, Vikhram V; Shannon, Mark A; Bashir, Rashid

    2015-04-01

    Dielectrophoretic separation of particles finds a variety of applications in the capture of species such as cells, viruses, proteins, DNA from biological systems, as well as other organic and inorganic contaminants from water. The ability to capture particles is constrained by poor volumetric scaling of separation force with respect to particle diameter, as well as the weak penetration of electric fields in the media. In order to improve the separation of sub-micron colloids, we present a scheme based on multiple interdigitated electrode arrays under mixed AC/DC bias. The use of high frequency longitudinal AC bias breaks the shielding effects through electroosmotic micromixing to enhance electric fields through the electrolyte, while a transverse DC bias between the electrode arrays enables penetration of the separation force to capture particles from the bulk of the microchannel. We determine the favorable biasing conditions for field enhancement with the help of analytical models, and experimentally demonstrate the improved capture from sub-micron colloidal suspensions with the mixed AC/DC electrostatic excitation scheme over conventional AC-DEP methods.

  15. Single-molecule detection of proteins with antigen-antibody interaction using resistive-pulse sensing of submicron latex particles

    Science.gov (United States)

    Takakura, T.; Yanagi, I.; Goto, Y.; Ishige, Y.; Kohara, Y.

    2016-03-01

    We developed a resistive-pulse sensor with a solid-state pore and measured the latex agglutination of submicron particles induced by antigen-antibody interaction for single-molecule detection of proteins. We fabricated the pore based on numerical simulation to clearly distinguish between monomer and dimer latex particles. By measuring single dimers agglutinated in the single-molecule regime, we detected single human alpha-fetoprotein molecules. Adjusting the initial particle concentration improves the limit of detection (LOD) to 95 fmol/l. We established a theoretical model of the LOD by combining the reaction kinetics and the counting statistics to explain the effect of initial particle concentration on the LOD. The theoretical model shows how to improve the LOD quantitatively. The single-molecule detection studied here indicates the feasibility of implementing a highly sensitive immunoassay by a simple measurement method using resistive-pulse sensing.

  16. Chemical and physical characteristics of long-range transport submicron particles at the central Tibet Plateau

    Science.gov (United States)

    Xu, J.; Zhang, Q.; Shi, J.; Ge, X.; Xie, C.; Wang, J.

    2016-12-01

    Tibetan Plateau, the biggest and highest plateau on the Earth, is an ideal location for studying long range transport of air pollution due to the minimum of local emission. Recent studies in this region have revealed a significant influx of air pollution from south Asia during pre-monsoon period because of the favorable atmospheric circulation and less precipitation. In order to characterize the chemical composition of aerosol particles in this pristine area and elucidate the sources and optical properties of transported aerosol pollutants, we conducted an intensive field study during June 2015 at a high elevation station (4730 m a.s.l) on the central Tibetan Plateau by deploying a suite of advanced instruments including an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS), a nephelometer, and a multi-angle absorption photometer (MAAP). The average mass concentration of submicron particular matter (PM1) for the whole campaign period was 1.85 µg m-3, with organics accounting for 64% of the mass, followed by sulfate (16%), black carbon (9%), ammonium (8%), and nitrate (3%). The mass concentrations and chemical properties of PM1 were significantly different between pre-monsoon and monsoon periods. Elevated aerosol pollution episodes were observed during pre-monsoon period, while aerosol concentrations were persistently low during monsoon period. Aerosol composition was generally similar during the whole campaign period. However, organic aerosol was more oxidized during premonsoon period with an average atomic oxygen-to-carbon (O/C) ratio of = 0.7 compared to O/C = 0.52 during monsoon period. HYSPLIT trajectory calculations revealed that most of the arriving air masses traveled long distances (>1,000 km) and went through the northwest of India during premonsoon period. Positive matrix factorization of the HR-ToF-AMS spectra of organic aerosol identified two oxygenated organic aerosol (OOA) factors - a less oxidized OOA (LO-OOA) and a more

  17. Mixing state of individual submicron carbon-containing particles and their seasonal variation in urban Guangzhou, China

    Directory of Open Access Journals (Sweden)

    G. Zhang

    2012-12-01

    Full Text Available Growing evidence suggests that size-resolved mixing state of carbon-containing particles is very critical in determining their optical properties, atmospheric lifetime, and impact on the environment. However, still little is known about the mixing state of particles in urban area of Pearl River Delta (PRD region, China. To investigate the mixing state of submicron carbon-containing particles, measurements were carried out during spring and fall periods of 2010 using a single particle aerosol mass spectrometer (SPAMS. Approximate 700 000 particles for each period were detected. This is the first report on the size-resolved mixing state of carbon-containing particles by direct observations in PRD region. Cluster analysis of single particle mass spectra was applied to identify carbon-containing particle classes. These classes represented ~80% and ~90% of all the detected particles for spring and fall periods, respectively. Carbon-containing particle classes mainly consisted of biomass/biofuel burning particles (Biomass, organic carbon (OC, fresh elemental carbon (EC-fresh, internally mixed OC and EC (ECOC, internally mixed EC with sulfate (EC-Sulfate, vanadium-containing ECOC (V-ECOC, and amines-containing particles (Amine. In spring, the top three ranked carbon-containing particle classes were ECOC (26.1%, Biomass (23.6% and OC (10%, respectively. However, the fraction of Biomass particles increased remarkably and predominated (61.0%, while the fraction of ECOC (3.0% and V-ECOC (0.1% significantly decreased in fall. To highlight the influence of monsoon on the properties of carbon-containing particles in urban Guangzhou, their size distribution, mixing state, and aerosol acidity were compared between spring and fall seasons. In addition, a case study was also performed to investigate how the formation of fog and haze influenced the mixing state of carbon-containing particles. These results are of importance in understanding atmospheric chemistry

  18. Mixing state of individual submicron carbon-containing particles and their seasonal variation in urban Guangzhou, China

    Science.gov (United States)

    Zhang, G.; Bi, X.; Li, L.; Chan, L. Y.; Li, M.; Wang, X.; Sheng, G.; Fu, J.; Zhou, Z.

    2012-12-01

    Growing evidence suggests that size-resolved mixing state of carbon-containing particles is very critical in determining their optical properties, atmospheric lifetime, and impact on the environment. However, still little is known about the mixing state of particles in urban area of Pearl River Delta (PRD) region, China. To investigate the mixing state of submicron carbon-containing particles, measurements were carried out during spring and fall periods of 2010 using a single particle aerosol mass spectrometer (SPAMS). Approximate 700 000 particles for each period were detected. This is the first report on the size-resolved mixing state of carbon-containing particles by direct observations in PRD region. Cluster analysis of single particle mass spectra was applied to identify carbon-containing particle classes. These classes represented ~80% and ~90% of all the detected particles for spring and fall periods, respectively. Carbon-containing particle classes mainly consisted of biomass/biofuel burning particles (Biomass), organic carbon (OC), fresh elemental carbon (EC-fresh), internally mixed OC and EC (ECOC), internally mixed EC with sulfate (EC-Sulfate), vanadium-containing ECOC (V-ECOC), and amines-containing particles (Amine). In spring, the top three ranked carbon-containing particle classes were ECOC (26.1%), Biomass (23.6%) and OC (10%), respectively. However, the fraction of Biomass particles increased remarkably and predominated (61.0%), while the fraction of ECOC (3.0%) and V-ECOC (0.1%) significantly decreased in fall. To highlight the influence of monsoon on the properties of carbon-containing particles in urban Guangzhou, their size distribution, mixing state, and aerosol acidity were compared between spring and fall seasons. In addition, a case study was also performed to investigate how the formation of fog and haze influenced the mixing state of carbon-containing particles. These results are of importance in understanding atmospheric chemistry and

  19. Identification of characteristic mass spectrometric markers for primary biological aerosol particles and comparison with field data from submicron pristine aerosol particles

    Science.gov (United States)

    Freutel, F.; Schneider, J.; Zorn, S. R.; Drewnick, F.; Borrmann, S.; Hoffmann, T.; Martin, S. T.

    2009-04-01

    The contribution of primary biological aerosol (PBA) to the total aerosol particle concentration is estimated to range between 25 and 80%, depending on location and season. Especially in the tropical rain forest it is expected that PBA is a major source of particles in the supermicron range, and is also an important fraction of the submicron aerosol. PBA particles like plant fragments, pollen, spores, fungi, viruses etc. contain chemical compounds as proteins, sugars, amino acids, chlorophyll, and cellular material as cellulose. For this reason we have performed mass spectrometric laboratory measurements (Aerodyne C-ToF and W-ToF AMS, single particle laser ablation instrument SPLAT) on pure submicron aerosol particles containing typical PBA compounds in order to identify typical mass spectral patterns of these compounds and to explain the observed fragmentation patterns on the basis of molecular structures. These laboratory data were compared to submicron particle mass spectra obtained during AMAZE-08 (Amazonian Aerosol CharacteriZation Experiment, Brazil, February/March 2008). The results indicate that characteristic m/z ratios for carbohydrates (e.g., glucose, saccharose, levoglucosan, mannitol) can be identified, for example m/z = 60(C2H4O2+) or m/z = 61(C2H5O2+). Certain characteristic peaks for amino acids were also identified in the laboratory experiments. In the field data from AMAZE-08, these characteristic peaks for carbohydrates and amino acids were found, and their contribution to the total organic mass was estimated to about 5%. Fragment ions from peptides and small proteins were also identified in laboratory experiments. Larger proteins, however, seem to become oxidized to CO2+ to a large extend in the vaporizing process of the AMS. Thus, detection of proteins in atmospheric aerosol particles with the AMS appears to be difficult.

  20. Effect of particle concentration on the structure and tribological properties of submicron particle SiC reinforced Ni metal matrix composite (MMC) coatings produced by electrodeposition

    Energy Technology Data Exchange (ETDEWEB)

    Guel, H., E-mail: harungul@duzce.edu.tr [Duzce University, Gumusova Vocational School, Department of Metallurgy, 81850, Duzce (Turkey); K Latin-Small-Letter-Dotless-I l Latin-Small-Letter-Dotless-I c, F.; Uysal, M.; Aslan, S.; Alp, A.; Akbulut, H. [Sakarya University, Engineering Faculty, Department of Metallurgical and Materials Engineering, Esentepe Campus, 54187, Sakarya (Turkey)

    2012-03-01

    In the present work, a nickel sulfate bath containing SiC submicron particles between 100 and 1000 nm was used as the plating electrolyte. The aim of this work is to obtain Ni-SiC metal matrix composites (MMCs) reinforced with submicron particles on steel surfaces with high hardness and wear resistance for using in anti-wear applications such as dies, tools and working parts for automobiles and vehicles. The influence of the SiC content in the electrolyte on particle distribution, microhardness and wear resistance of nano-composite coatings was studied. During the electroplating process, the proper stirring speed was also determined for sub-micron SiC deposition with Ni matrix. The Ni films were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. The depositions were controlled to obtain a specific thickness (between 50 and 200 {mu}m) and volume fraction of the particles in the matrix (between 0.02 and 0.10). The hardness of the coatings was measured to be 280-571 HV depending on the particle volume in the Ni matrix. The tribological behaviors of the electrodeposited SiC nanocomposite coatings sliding against an M50 steel ball (O 10 mm) were examined on a tribometer. All the friction and wear tests were performed without lubrication at room temperature and in the ambient air (with a relative humidity of 55-65%). The results showed that the wear resistance of the nanocomposites was approximately 2-2.2 times more than those of unreinforced Ni.

  1. Characterization of Semi-volatility of Atmospheric Submicron Particles at a Regional Background Site in North China

    Science.gov (United States)

    He, L. Y.

    2015-12-01

    HE Lingyan1, HUANG Congni1, HUANG Xiaofeng11. Key Laboratory for Urban Habitat Environmental Science and Technology, School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen 518055, China Abstract:The coupling of a Thermal Denuder (TD) with a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) was used in Xianghe, which is a regional background site in North China, during June - July, 2013 to on-line measure the mass concentrations and semi-volatilities of atmospheric submicron particles, including organic matter (OM), SO42- , NO3-, NH4+, and Cl-. The total PM1 mass concentration measured was averagely (47.9±47.3) mg/m3 during the campaign, with OM accounting for 38.2% of the total PM1 mass, followed by SO42- (33.7%), NH4+ (13.8%), NO3- (12.3%), and Cl- (2.0%). It was found that NO3- and Cl- had the highest semi-volatility, with about 60% of them evaporating into the gas phase by increasing the temperature to 50 °C, while SO42- showed the lowest semi-volatility, with almost 90% of its mass remaining in the particle phase at 50 °C. The semi-volatility of OM and NH4+ was at the middle level. The semi-volatility of NO3- was affected by the pollution level of the atmospheric submicron particles since it showed an increasing trend with the increasing of PM1 at 50 °C. The oxygen-to-carbon ration of organic aerosol was 0.47 to 0.60 by increasing the temperature from 50 ℃ to 200 °C. In addition, the semi-volatility of the PM1 species with vacuum aerodynamic diameters of 60-2000 nm was little size dependent. The calculation based on the high-resolution mass spectra of OM showed that CO2+-containing organic species had lower semi-volatility, while C4H9+-containing organic species had higher semi-volatility. The semi-volatility of OM was found to be negatively related to its oxidation state. The quantitative result of atmospheric submicron particles' semi-volatility is essential to the research of the physicochemical

  2. Aerosols in the tropical and subtropical UT/LS: in-situ measurements of submicron particle abundance and volatility

    Directory of Open Access Journals (Sweden)

    S. Borrmann

    2010-06-01

    Full Text Available Processes occurring in the tropical upper troposphere (UT, the Tropical Transition Layer (TTL, and the lower stratosphere (LS are of importance for the global climate, for stratospheric dynamics and air chemistry, and for their influence on the global distribution of water vapour, trace gases and aerosols. In this contribution we present aerosol and trace gas (in-situ measurements from the tropical UT/LS over Southern Brazil, Northern Australia, and West Africa. The instruments were operated on board of the Russian high altitude research aircraft M-55 "Geophysica" and the DLR Falcon-20 during the campaigns TROCCINOX (Araçatuba, Brazil, February 2005, SCOUT-O3 (Darwin, Australia, December 2005, and SCOUT-AMMA (Ouagadougou, Burkina Faso, August 2006. The data cover submicron particle number densities and volatility from the COndensation PArticle counting System (COPAS, as well as relevant trace gases like N2O, ozone, and CO. We use these trace gas measurements to place the aerosol data into a broader atmospheric context. Also a juxtaposition of the submicron particle data with previous measurements over Costa Rica and other tropical locations between 1999 and 2007 (NASA DC-8 and NASA WB-57F is provided. The submicron particle number densities, as a function of altitude, were found to be remarkably constant in the tropical UT/LS altitude band for the two decades after 1987. Thus, a parameterisation suitable for models can be extracted from these measurements. Compared to the average levels in the period between 1987 and 2007 a slight increase of particle abundances was found for 2005/2006 at altitudes with potential temperatures, Θ, above 430 K. The origins of this increase are unknown except for increases measured during SCOUT-AMMA. Here the eruption of the Soufrière Hills volcano in the Caribbean caused elevated particle mixing ratios. The vertical profiles from Northern hemispheric mid-latitudes between 1999 and 2006 also are

  3. Aerosols in the tropical and subtropical UT/LS: in-situ measurements of submicron particle abundance and volatility

    Science.gov (United States)

    Borrmann, S.; Kunkel, D.; Weigel, R.; Minikin, A.; Deshler, T.; Wilson, J. C.; Curtius, J.; Volk, C. M.; Homan, C. D.; Ulanovsky, A.; Ravegnani, F.; Viciani, S.; Shur, G. N.; Belyaev, G. V.; Law, K. S.; Cairo, F.

    2010-06-01

    Processes occurring in the tropical upper troposphere (UT), the Tropical Transition Layer (TTL), and the lower stratosphere (LS) are of importance for the global climate, for stratospheric dynamics and air chemistry, and for their influence on the global distribution of water vapour, trace gases and aerosols. In this contribution we present aerosol and trace gas (in-situ) measurements from the tropical UT/LS over Southern Brazil, Northern Australia, and West Africa. The instruments were operated on board of the Russian high altitude research aircraft M-55 "Geophysica" and the DLR Falcon-20 during the campaigns TROCCINOX (Araçatuba, Brazil, February 2005), SCOUT-O3 (Darwin, Australia, December 2005), and SCOUT-AMMA (Ouagadougou, Burkina Faso, August 2006). The data cover submicron particle number densities and volatility from the COndensation PArticle counting System (COPAS), as well as relevant trace gases like N2O, ozone, and CO. We use these trace gas measurements to place the aerosol data into a broader atmospheric context. Also a juxtaposition of the submicron particle data with previous measurements over Costa Rica and other tropical locations between 1999 and 2007 (NASA DC-8 and NASA WB-57F) is provided. The submicron particle number densities, as a function of altitude, were found to be remarkably constant in the tropical UT/LS altitude band for the two decades after 1987. Thus, a parameterisation suitable for models can be extracted from these measurements. Compared to the average levels in the period between 1987 and 2007 a slight increase of particle abundances was found for 2005/2006 at altitudes with potential temperatures, Θ, above 430 K. The origins of this increase are unknown except for increases measured during SCOUT-AMMA. Here the eruption of the Soufrière Hills volcano in the Caribbean caused elevated particle mixing ratios. The vertical profiles from Northern hemispheric mid-latitudes between 1999 and 2006 also are compact enough to derive a

  4. Effect of reinforcing submicron SiC particles on the wear of electrolytic NiP coatings Part 1. Uni-directional sliding

    OpenAIRE

    Aslanyan, I. R.; Bonino, Jean-Pierre; Celis, J.-P.

    2006-01-01

    As-plated and annealed NiP coatings and composite NiP-SiC coatings were investigated in uni-directional ball-on-disc sliding tests. Abrasive wear was noticed in the case of composite NiP coatings containing submicron SiC particles, whereas in NiP coatings oxidational wear was active. The addition of submicron SiC particles not only increases the hardness of these electrolytic coatings but also hinders the formation of an oxide film in the sliding wear track. As a consequence, the wear loss on...

  5. A novel method to detect unlabeled inorganic nanoparticles and submicron particles in tissue by sedimentation field-flow fractionation

    Science.gov (United States)

    Deering, Cassandra E; Tadjiki, Soheyl; Assemi, Shoeleh; Miller, Jan D; Yost, Garold S; Veranth, John M

    2008-01-01

    A novel methodology to detect unlabeled inorganic nanoparticles was experimentally demonstrated using a mixture of nano-sized (70 nm) and submicron (250 nm) silicon dioxide particles added to mammalian tissue. The size and concentration of environmentally relevant inorganic particles in a tissue sample can be determined by a procedure consisting of matrix digestion, particle recovery by centrifugation, size separation by sedimentation field-flow fractionation (SdFFF), and detection by light scattering. Background Laboratory nanoparticles that have been labeled by fluorescence, radioactivity, or rare elements have provided important information regarding nanoparticle uptake and translocation, but most nanomaterials that are commercially produced for industrial and consumer applications do not contain a specific label. Methods Both nitric acid digestion and enzyme digestion were tested with liver and lung tissue as well as with cultured cells. Tissue processing with a mixture of protease enzymes is preferred because it is applicable to a wide range of particle compositions. Samples were visualized via fluorescence microscopy and transmission electron microscopy to validate the SdFFF results. We describe in detail the tissue preparation procedures and discuss method sensitivity compared to reported levels of nanoparticles in vivo. Conclusion Tissue digestion and SdFFF complement existing techniques by precisely identifying unlabeled metal oxide nanoparticles and unambiguously distinguishing nanoparticles (diameter<100 nm) from both soluble compounds and from larger particles of the same nominal elemental composition. This is an exciting capability that can facilitate epidemiological and toxicological research on natural and manufactured nanomaterials. PMID:19055780

  6. Influence of trans-boundary biomass burning impacted air masses on submicron particle number concentrations and size distributions

    Science.gov (United States)

    Betha, Raghu; Zhang, Zhe; Balasubramanian, Rajasekhar

    2014-08-01

    Submicron particle number concentration (PNC) and particle size distribution (PSD) in the size range of 5.6-560 nm were investigated in Singapore from 27 June 2009 through 6 September 2009. Slightly hazy conditions lasted in Singapore from 6 to 10 August. Backward air trajectories indicated that the haze was due to the transport of biomass burning impacted air masses originating from wild forest and peat fires in Sumatra, Indonesia. Three distinct peaks in the morning (08:00-10:00), afternoon (13:00-15:00) and evening (16:00-20:00) were observed on a typical normal day. However, during the haze period no distinct morning and afternoon peaks were observed and the PNC (39,775 ± 3741 cm-3) increased by 1.5 times when compared to that during non-haze periods (26,462 ± 6017). The morning and afternoon peaks on the normal day were associated with the local rush hour traffic while the afternoon peak was induced by new particle formation (NPF). Diurnal profiles of PNCs and PSDs showed that primary particle peak diameters were large during the haze (60 nm) period when compared to that during the non-haze period (45.3 nm). NPF events observed in the afternoon period on normal days were suppressed during the haze periods due to heavy particle loading in atmosphere caused by biomass burning impacted air masses.

  7. Stochastic analysis of a collection process of submicron particles on a single fiber accounting for the changes in flow field due to particle collection

    Energy Technology Data Exchange (ETDEWEB)

    Bang, Jong Geun; Yoon, Woong Sup [Yonsei University, Seoul (Korea, Republic of)

    2014-09-15

    Flow effects on the collection of submicron particles by a single fiber are investigated by stochastic analysis of the particle deposition evolution. The incident particle-laden stream is simulated by a Lagrangian-Eulerian approach, while the flows around a fiber and particles accumulation are solved using the Lattice Boltzmann method in conjunction with Brownian dynamics to trace the trajectory of randomly moving particles. A boundary surface on the fiber also evolves to include the changing morphology due to particle deposition. The simulation method is validated for collection efficiencies and pressure drop of clean fiber. Brownian effects on particle accumulation were examined in terms of the Peclet number. Predictions of evolving particle-layered filter geometry showed a strong effect of carrier gas convection on the extent and the morphology of the particle accumulation, which, in turn affected the morphology of the filter. This strong interaction between the carrier-gas convection and the filter membrane causes more active particle accumulation, and thus at all Peclet numbers examined with carrier-gas convection yielded higher collection efficiencies, but with a higher pressure drop.

  8. Aerosol and NOx emission factors and submicron particle number size distributions in two road tunnels with different traffic regimes

    Directory of Open Access Journals (Sweden)

    D. Imhof

    2006-01-01

    Full Text Available Measurements of aerosol particle number size distributions (18–700 nm, mass concentrations (PM2.5 and PM10 and NOx were performed in the Plabutsch tunnel, Austria, and in the Kingsway tunnel, United Kingdom. These two tunnels show different characteristics regarding the roadway gradient, the composition of the vehicle fleet and the traffic frequency. The submicron particle size distributions contained a soot mode in the diameter range D=80–100 nm and a nucleation mode in the range of D=20–40 nm. In the Kingsway tunnel with a significantly lower particle number and volume concentration level than in the Plabutsch tunnel, a clear diurnal variation of nucleation and soot mode particles correlated to the traffic density was observed. In the Plabutsch tunnel, soot mode particles also revealed a diurnal variation, whereas no substantial variation was found for the nucleation mode particles. During the night a higher number concentration of nucleation mode particles were measured than soot mode particles and vice versa during the day. In this tunnel with very high soot emissions during daytime due to the heavy-duty vehicle (HDV share of 18% and another 40% of diesel driven light-duty vehicles (LDV semivolatile species condense on the pre-existing soot surface area rather than forming new particles by homogeneous nucleation. With the low concentration of soot mode particles in the Kingsway tunnel, also the nucleation mode particles exhibit a diurnal variation. From the measured parameters real-world traffic emission factors were estimated for the whole vehicle fleet as well as differentiated into the two categories LDV and HDV. In the particle size range D=18–700 nm, each vehicle of the mixed fleet emits (1.50±0.08×1014 particles km-1 (Plabutsch and (1.26±0.10×1014 particles km-1 (Kingsway, while particle volume emission factors of 0.209±0.008 cm3 km-1 and 0.036±0.004 cm3 km-1, respectively, were obtained. PM1 emission factors of 104±4 mg

  9. Application of I-structure though-glass interconnect filled with submicron gold particles to a hermetic sealing device

    Science.gov (United States)

    Nomura, Kazuya; Okada, Akiko; Shoji, Shuichi; Ogashiwa, Toshinori; Mizuno, Jun

    2016-10-01

    We propose hermetic sealing of a glass-to-glass structure with an I-structure through-glass interconnect via (TGV) filled with submicron Au particles. The top and bottom bumps and the TGV were formed by a simple filling process with a bump-patterned dry film resist. The sealing devices consisting of two glass substrates were bonded via Au interlayers. Vacuum ultraviolet irradiation in the presence of oxygen gas (VUV/O3) pretreatment was used for low-temperature Au-Au bonding at 200 °C. The bonded samples showed He leakage rates of less than 1.3  ×  10-9 Pa m3 s-1. The cross-sectional scanning electron microscope images of the fabricated I-structure TGV showed perfect adhesion between the I-structure TGV and glass substrate. These results indicate that the proposed I-structure TGV is suitable for hermetic sealing devices.

  10. A novel method to detect unlabeled inorganic nanoparticles and submicron particles in tissue by sedimentation field-flow fractionation

    Directory of Open Access Journals (Sweden)

    Yost Garold S

    2008-12-01

    Full Text Available Abstract A novel methodology to detect unlabeled inorganic nanoparticles was experimentally demonstrated using a mixture of nano-sized (70 nm and submicron (250 nm silicon dioxide particles added to mammalian tissue. The size and concentration of environmentally relevant inorganic particles in a tissue sample can be determined by a procedure consisting of matrix digestion, particle recovery by centrifugation, size separation by sedimentation field-flow fractionation (SdFFF, and detection by light scattering. Background Laboratory nanoparticles that have been labeled by fluorescence, radioactivity, or rare elements have provided important information regarding nanoparticle uptake and translocation, but most nanomaterials that are commercially produced for industrial and consumer applications do not contain a specific label. Methods Both nitric acid digestion and enzyme digestion were tested with liver and lung tissue as well as with cultured cells. Tissue processing with a mixture of protease enzymes is preferred because it is applicable to a wide range of particle compositions. Samples were visualized via fluorescence microscopy and transmission electron microscopy to validate the SdFFF results. We describe in detail the tissue preparation procedures and discuss method sensitivity compared to reported levels of nanoparticles in vivo. Conclusion Tissue digestion and SdFFF complement existing techniques by precisely identifying unlabeled metal oxide nanoparticles and unambiguously distinguishing nanoparticles (diameter

  11. Extending the limits of direct force measurements: colloidal probes from sub-micron particles.

    Science.gov (United States)

    Helfricht, Nicolas; Mark, Andreas; Dorwling-Carter, Livie; Zambelli, Tomaso; Papastavrou, Georg

    2017-07-13

    Direct force measurements by atomic force microscopy (AFM) in combination with the colloidal probe technique are widely used to determine interaction forces in colloidal systems. However, a number of limitations are still preventing a more universal applicability of this technique. Currently, one of the most significant limitations is that only particles with diameters of several micrometers can be used as probe particles. Here, we present a novel approach, based on the combination of nanofluidics and AFM (also referred to as FluidFM-technique), that allows to overcome this size limit and extend the size of suitable probe particles below diameters of 500 nanometers. Moreover, by aspiration of colloidal particles with a hollow AFM-cantilever, the immobilization process is independent of the particle's surface chemistry. Furthermore, the probe particles can be exchanged in situ. The applicability of the FluidFM-technique is demonstrated with silica particles, which are also the types of particles most often used for the preparation of colloidal probes. By comparing 'classical' colloidal probes, i.e. probes from particles irreversibly attached with glue, and various particle sizes aspirated by the FluidFM-technique, we can quantitatively evaluate the instrumental limits. Evaluation of the force profiles demonstrate that even for 500 nm silica particles the diffuse layer properties can be evaluated quantitatively. Therefore, direct force measurements on the level of particle sizes used in industrial formulations will become available in the future.

  12. Preparation and properties of films cast from mixtures of poly(vinyl alcohol) and submicron particles prepared from amylose-palmitic acid inclusion complexes.

    Science.gov (United States)

    Fanta, George F; Selling, Gordon W; Felker, Frederick C; Kenar, James A

    2015-05-05

    The use of starch in polymer composites for film production has been studied for increasing biodegradability, improving film properties and reducing cost. In this study, submicron particles were prepared from amylose-sodium palmitate complexes both by rapidly cooling jet-cooked starch-palmitic acid mixtures and by acidifying solutions of starch-sodium palmitate complexes. Films were cast containing poly(vinyl alcohol) (PVOH) with up to 50% starch particles. Tensile strength decreased and Young's modulus increased with starch concentration, but percent elongations remained similar to controls regardless of preparation method or starch content. Microscopy showed particulate starch distribution in films made with rapidly cooled starch-palmitic acid particles but smooth, diffuse starch staining with acidified sodium palmitate complexes. The mild effects on tensile properties suggest that submicron starch particles prepared from amylose-palmitic acid complexes provide a useful, commercially viable approach for PVOH film modification.

  13. A novel apparatus for in situ compression of submicron structures and particles in a high resolution SEM.

    Science.gov (United States)

    Romeis, S; Paul, J; Ziener, M; Peukert, W

    2012-09-01

    We report on the development and characterization of a novel in situ manipulation device to perform stressing experiments on the submicron scale inside a high resolution field emission scanning electron microscope. The instrument comprises two main assembly groups: an upper part for positioning and moving a mounted probe and a force sensor as well as a specimen support as lower part. The upper part consists of a closed loop tripod piezoelectric scanner mounted on a self-locking coarse positioning stage. Two interlocked steel springs and a linear variable differential transformer measuring the springs' deflections compose the lower part of the instrument. This arrangement acts as force-sensor and sample support. In comparison to already well-established concepts a wide measuring range is covered by adjusting the spring constant between 30 N/m and 50000 N/m. Moreover, the new device offers striking advantages with respect to force calibration and sample deformation measurements. Force calibration is performed using the eigenfrequency of the force detection system directly inside the SEM. Deformation data are obtained with high accuracy by simultaneously recording displacements above and below the specimen. The detrimental apparatus compliance is determined, and the influence on measured data subsequently minimized: an easy to validate two-springs-in-series model is used for data correction. A force resolution in normal direction of 100 nN accompanied by a sample deformation resolution of 5 nm can be achieved with the instrument using an appropriate load cell stiffness. The capabilities and versatility of this instrument are exemplified by compression experiments performed on submicron amorphous silica particles.

  14. Deformation Behavior of Sub-micron and Micron Sized Alumina Particles in Compression.

    Energy Technology Data Exchange (ETDEWEB)

    Sarobol, Pylin; Chandross, Michael E.; Carroll, Jay; Mook, William; Boyce, Brad; Kotula, Paul Gabriel; McKenzie, Bonnie Beth; Bufford, Daniel Charles; Hall, Aaron Christopher.

    2014-09-01

    The ability to integrate ceramics with other materials has been limited due to high temperature (>800degC) ceramic processing. Recently, researchers demonstrated a novel process , aerosol deposition (AD), to fabricate ceramic films at room temperature (RT). In this process, sub - micro n sized ceramic particles are accelerated by pressurized gas, impacted on the substrate, plastically deformed, and form a dense film under vacuum. This AD process eliminates high temperature processing thereby enabling new coatings and device integration, in which ceramics can be deposited on metals, plastics, and glass. However, k nowledge in fundamental mechanisms for ceramic particle s to deform and form a dense ceramic film is still needed and is essential in advancing this novel RT technology. In this wo rk, a combination of experimentation and atomistic simulation was used to determine the deformation behavior of sub - micron sized ceramic particle s ; this is the first fundamental step needed to explain coating formation in the AD process . High purity, singl e crystal, alpha alumina particles with nominal size s of 0.3 um and 3.0 um were examined. Particle characterization, using transmission electron microscopy (TEM ), showed that the 0.3 u m particles were relatively defect - free single crystals whereas 3.0 u m p articles were highly defective single crystals or particles contained low angle grain boundaries. Sub - micron sized Al 2 O 3 particles exhibited ductile failure in compression. In situ compression experiments showed 0.3um particles deformed plastically, fractured, and became polycrystalline. Moreover, dislocation activit y was observed within the se particles during compression . These sub - micron sized Al 2 O 3 particles exhibited large accum ulated strain (2 - 3 times those of micron - sized particles) before first fracture. I n agreement with the findings from experimentation , a tomistic simulation s of nano - Al 2 O 3 particles showed dislocation slip and

  15. Number size distributions and seasonality of submicron particles in Europe 2008-2009

    NARCIS (Netherlands)

    Asmi, A.; Wiedensohler, A.; Laj, P.; Fjaeraa, A.-M.; Sellegri, K.; Birmili, W.; Weingartner, E.; Baltensperger, U.; Zdimal, V.; Zikova, N.; Putaud, J.-P.; Marinoni, A.; Tunved, P.; Hansson, H.-C.; Fiebig, M.; Kivekäs, N.; Lihavainen, H.; Asmi, E.; Ulevicius, V.; Aalto, P.P.; Swietlicki, E.; Kristensson, A.; Mihalopoulos, N.; Kalivitis, N.; Kalapov, I.; Kiss, G.; Leeuw, G. de; Henzing, B.; Harrison, R.M.; Beddows, D.; O'Dowd, C.; Jennings, S.G.; Flentje, H.; Weinhold, K.; Meinhardt, F.; Ries, L.; Kulmala, M.

    2011-01-01

    Two years of harmonized aerosol number size distribution data from 24 European field monitoring sites have been analysed. The results give a comprehensive overview of the European near surface aerosol particle number concentrations and number size distributions between 30 and 500 nm of dry particle

  16. THE INFLUENCE OF CARBON BURNOUT ON SUBMICRON PARTICLE FORMATION FROM EMULSIFIED FUEL OIL COMBUSTION

    Science.gov (United States)

    The paper gives results of an examination of particle behavior and particle size distributions from the combustion of different fuel oils and emulsified fuels in three experimental combusators. Results indicate that improved carbon (C) burnout from fule oil combustion, either by...

  17. THE INFLUENCE OF CARBON BURNOUT ON SUBMICRON PARTICLE FORMATION FROM EMULSIFIED FUEL OIL COMBUSTION

    Science.gov (United States)

    The paper gives results of an examination of particle behavior and particle size distributions from the combustion of different fuel oils and emulsified fuels in three experimental combusators. Results indicate that improved carbon (C) burnout from fule oil combustion, either by...

  18. Stable, Free-space Optical Trapping and Manipulation of Sub-micron Particles in an Integrated Microfluidic Chip

    Science.gov (United States)

    Kim, Jisu; Shin, Jung H.

    2016-01-01

    We demonstrate stable, free-space optical trapping and manipulation in an integrated microfluidic chip using counter-propagating beams. An inverted ridge-type waveguide made of SU8 is cut across by an open trench. The design of the waveguide provides low propagation losses and small divergence of the trapping beam upon emergence from the facet, and the trench designed to be deeper and wider than the optical mode enables full utilization of the optical power with an automatic alignment for counter-propagating beams in a trap volume away from all surfaces. After integration with polydimethylsiloxane (PDMS) microfluidic channel for particle delivery, 0.65 μm and 1 μm diameter polystyrene beads were trapped in free space in the trench, and manipulated to an arbitrary position between the waveguides with a resolution of < 100 nm. Comparison with numerical simulations confirm stable trapping of sub-micron particles, with a 10 kBT threshold power of less than 1 mW and a stiffness that can be 1 order of magnitude larger than that of comparable fiber-based trapping methods. PMID:27653191

  19. Cold Spray Coating of Submicronic Ceramic Particles on Poly(vinyl alcohol) in Dry and Hydrogel States

    Science.gov (United States)

    Moreau, David; Borit, François; Corté, Laurent; Guipont, Vincent

    2017-06-01

    We report an approach using cold spray technology to coat poly(vinyl alcohol) (PVA) in polymer and hydrogel states with hydroxyapatite (HA). Using porous aggregated HA powder, we hypothesized that fragmentation of the powder upon cold spray could lead to formation of a ceramic coating on the surface of the PVA substrate. However, direct spraying of this powder led to complete destruction of the swollen PVA hydrogel substrate. As an alternative, HA coatings were successfully produced by spraying onto dry PVA substrates prior to swelling in water. Dense homogeneous HA coatings composed of submicron particles were obtained using rather low-energy spraying parameters (temperature 200-250 °C, pressure 1-3 MPa). Coated PVA substrates could swell in water without removal of the ceramic layer to form HA-coated hydrogels. Microscopic observations and in situ measurements were used to explain how local heating and impact of sprayed aggregates induced surface roughening and strong binding of HA particles to the molten PVA substrate. Such an approach could lead to design of ceramic coatings whose roughness and crystallinity can be finely adjusted to improve interfacing with biological tissues.

  20. Submicron polyacrolein particles in situ embedded with upconversion nanoparticles for bioassay

    Science.gov (United States)

    Generalova, A. N.; Kochneva, I. K.; Khaydukov, E. V.; Semchishen, V. A.; Guller, A. E.; Nechaev, A. V.; Shekhter, A. B.; Zubov, V. P.; Zvyagin, A. V.; Deyev, S. M.

    2015-01-01

    We report a new surface modification approach of upconversion nanoparticles (UCNPs) structured as inorganic hosts NaYF4 codoped with Yb3+ and Er3+ based on their encapsulation in a two-stage process of precipitation polymerization of acrolein under alkaline conditions in the presence of UCNPs. The use of tetramethylammonium hydroxide both as an initiator of acrolein polymerization and as an agent for UCNP hydrophilization made it possible to increase the polyacrolein yield up to 90%. This approach enabled the facile, lossless embedment of UCNPs into the polymer particles suitable for bioassay. These particles are readily dispersible in aqueous and physiological buffers, exhibiting excellent photoluminescence properties, chemical stability, and also allow the control of particle diameters. The feasibility of the as-produced photoluminescent polymer particles mean-sized 260 nm for in vivo optical whole-animal imaging was also demonstrated using a home-built epi-luminescence imaging system.We report a new surface modification approach of upconversion nanoparticles (UCNPs) structured as inorganic hosts NaYF4 codoped with Yb3+ and Er3+ based on their encapsulation in a two-stage process of precipitation polymerization of acrolein under alkaline conditions in the presence of UCNPs. The use of tetramethylammonium hydroxide both as an initiator of acrolein polymerization and as an agent for UCNP hydrophilization made it possible to increase the polyacrolein yield up to 90%. This approach enabled the facile, lossless embedment of UCNPs into the polymer particles suitable for bioassay. These particles are readily dispersible in aqueous and physiological buffers, exhibiting excellent photoluminescence properties, chemical stability, and also allow the control of particle diameters. The feasibility of the as-produced photoluminescent polymer particles mean-sized 260 nm for in vivo optical whole-animal imaging was also demonstrated using a home-built epi-luminescence imaging

  1. Characterisation of sub-micron particle number concentrations and formation events in the western Bushveld Igneous Complex, South Africa

    Directory of Open Access Journals (Sweden)

    A. Hirsikko

    2012-05-01

    Full Text Available South Africa holds significant mineral resources, with a substantial fraction of these reserves occurring and being processed in a large geological structure termed the Bushveld Igneous Complex (BIC. The area is also highly populated by informal, semi-formal and formal residential developments. However, knowledge of air quality and research related to the atmosphere is still very limited in the area. In order to investigate the characteristics and processes affecting sub-micron particle number concentrations and formation events, air ion and aerosol particle size distributions and number concentrations, together with meteorological parameters, trace gases and particulate matter (PM were measured for over two years at Marikana in the heart of the western BIC. The observations showed that trace gas (i.e. SO2, NOx, CO and black carbon concentrations were relatively high, but in general within the limits of local air quality standards. The area was characterised by very high condensation sink due to background aerosol particles, PM10 and O3 concentration. The results indicated that high amounts of Aitken and accumulation mode particles originated from domestic burning for heating and cooking in the morning and evening, while during daytime SO2-based nucleation followed by the growth by condensation of vapours from industrial, residential and natural sources was the most probable source for large number concentrations of nucleation and Aitken mode particles. Nucleation event day frequency was extremely high, i.e. 86% of the analysed days, which to the knowledge of the authors is the highest frequency ever reported. The air mass back trajectory and wind direction analyses showed that the secondary particle formation was influenced both by local and regional pollution and vapour sources. Therefore, our observation of the annual cycle and magnitude of the particle formation and growth rates during

  2. Oxygenated organic functional groups and their sources in single and submicron organic particles in MILAGRO 2006 campaign

    Directory of Open Access Journals (Sweden)

    S. Liu

    2009-09-01

    Full Text Available Fourier Transform Infrared (FTIR and X-ray Fluorescence (XRF were used to measure organic functional groups and elements of submicron particles collected during MILAGRO in March 2006 on three platforms: the Mexico City urban area (SIMAT, the high altitude site at 4010 m (Altzomoni, and the NCAR C130 aircraft. Scanning Transmission X-ray Microscopy (STXM and Near-Edge X-ray Absorption Fine Structure (NEXAFS were applied to single particle organic functional group abundance analysis of particles simultaneously collected at SIMAT and C130. Correlations of elemental concentrations showed different groups of source-related elements at SIMAT, Altzomoni, and C130, suggesting different processes affecting the air masses sampled at the three platforms. Cluster analysis resulted in seven distinct clusters of FTIR spectra, with the last three clusters consisting of spectra collected almost exclusively on the C130 platform, reflecting the variety of sources contributing to C130 samples. Positive Matrix Factorization (PMF of STXM-NEXAFS spectra identified three main factors representing soot, secondary, and biomass burning type spectra. PMF of FTIR spectra resulted in two fossil fuel combustion factors and one biomass burning factor, the former representative of source regions to the northeast and southwest of SIMAT. Alkane, carboxylic acid, amine, and alcohol functional groups were mainly associated with combustion related sources, while non-acid carbonyl groups were likely from biomass burning events. The majority of OM and O/C was attributed to combustion sources, although no distinction between direct emissions and atmospherically processed OM could be identified.

  3. Oxygenated organic functional groups and their sources in single and submicron organic particles in MILAGRO 2006 campaign

    Directory of Open Access Journals (Sweden)

    S. Liu

    2009-02-01

    Full Text Available Fourier Transform Infrared (FTIR and X-ray Fluorescence (XRF were used to measure organic functional groups and elements of submicron particles collected during MILAGRO in March 2006 on three platforms: the Mexico City urban area (SIMAT, the high altitude site at 4010 m (Altzomoni, and the NCAR C130 aircraft. Scanning transmission X-ray Microscopy (STXM and Near-Edge X-ray Absorption Fine Structure (NEXAFS were applied to single particle organic functional group abundance analysis of particles simultaneously collected at SIMAT and C130. Correlations of elemental concentrations showed different groups of source related elements at SIMAT, Altzomoni, and C130, suggesting different processes affecting the air masses sampled at the three platforms. Cluster analysis resulted in seven distinct Clusters of FTIR spectra, with the last three clusters consisting of spectra collected almost exclusively on the C130 platform, reflecting the variety of sources contributing to C130 samples. Positive Matrix Factorization (PMF of NEXAFS-STXM spectra identified three main factors representing soot, secondary, and biomass burning type spectra. PMF of FTIR spectra resulted in three fossil fuel combustion type factors, one biomass burning factor, and one mixed or processed factor. The fossil fuel combustion type factors were found to have the largest contributions to OM, while the processed factor has the largest O/C among all factors. Alkane, carboxylic acid, and amine functional groups were mainly associated with combustion related sources, while alcohol groups were likely from atmospheric processing of mixed sources. While the processed factor has the highest O/C, half of the OM and O/C measured could be attributed directly to fossil fuel combustion sources. Both PMF of NEXAFS-STXM spectra and PMF of FTIR spectra indicate that the combustion type factors are more affected by fluctuations in local sources, while the processed factors are more consistent during the

  4. Submicron writing by laser irradiation on metal nano-particle dispersed films toward flexible electronics

    Science.gov (United States)

    Watanabe, Akira; Aminuzzaman, Mohammod; Miyashita, Tokuji

    2009-02-01

    The requirement for microwiring technology by a wet process has significantly increased recently toward the achievement of printable and flexible electronics. We have developed the metal microwiring with a resolution higher than 1 μm by the laser direct writing technique using Ag and Cu nano-particle-dispersed films as precursors. The technique was applied to the microwiring on a flexible and transparent polymer film. The metallization is caused in a micro-region by focused laser beam, which reduces the thermal damage of the flexible polymer substrate during the metallization process. The laser direct writing technique is based on the efficient and fast conversion of photon energy to thermal energy by direct excitation of the plasmon absorption of a metal nano-particle, which provides Cu microwiring with a low resistivity owing to the inhibition of the surface oxidation of the Cu nano-particle.

  5. Modeling of optical binding of submicron aerosol particles in counterpropagating Bessel beams

    Science.gov (United States)

    Thanopulos, I.; Luckhaus, D.; Signorell, R.

    2017-06-01

    We theoretically investigate the interparticle force between a pair of spherical aerosol nanoparticles in a dual counterpropagating Bessel beam configuration. We study the dependence of optical binding in the aerosol phase on the wavelength of the electromagnetic radiation, the particle radius, and the refractive index, including the cases of weak, moderate, and strong light absorption by the particles. We also investigate the relation between optical binding and the time-averaged intensity of the incident and scattered light. Our results show that optical binding in the aerosol phase depends strongly on the specific values of these parameters. This explains some of the difficulties associated with optical binding experiments with aerosol nanoparticles.

  6. Photothermal heating enabled by plasmonic nanoantennas for electrokinetic manipulation and sorting of submicron particles

    DEFF Research Database (Denmark)

    Ndukaife, Justus C.; Mishra, Avanish; Guler, Urcan

    2014-01-01

    The photo-induced collective heating enabled by a plasmonic nanoantenna array is for the first time harnessed for rapid concentration, manipulation and sorting of particles, with high throughput. This work could find application in biosensing, and surface enhanced spectroscopies © 2014 OSA....

  7. Bragg diffraction from sub-micron particles isolated by optical tweezers

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Yuan, E-mail: ygao0709@anl.gov; Harder, Ross; Southworth, Stephen; Guest, Jeffrey; Ocola, Leonidas; Young, Linda [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Scherer, Norbert; Yan, Zijie [Department of Chemistry, University of Chicago, Chicago, IL 60637 (United States); Pelton, Matthew [Department of Physics, University of Maryland, Baltimore County, MD 21250 (United States)

    2016-07-27

    We describe an apparatus using dynamic holographic optical tweezers which is capable of trapping and aligning a single micron scale anisotropic ZnO particle for x-ray Bragg diffraction experiments. The optical tweezers demonstrate enough stability to perform coherent x-ray diffraction imaging.

  8. Use of sub-micron sized resin particles for removal of endocrine disrupting compounds and pharmaceuticals from water and wastewater.

    Science.gov (United States)

    Murray, Audrey; Örmeci, Banu; Lai, Edward P C

    2017-01-01

    Endocrine disrupting compounds (EDCs) and pharmaceuticals pose a challenge for water and wastewater treatment because they exist at very low concentrations in the presence of substances at much higher concentrations competing for adsorption sites. Sub-micron sized resin particles (approximately 300nm in diameter) (SMR) were tested to evaluate their potential as a treatment for EDCs including: 17-β estradiol (E2), 17-α ethinylestradiol (EE2), estrone (E1), bisphenol A (BPA), and diethylstilbestrol (DES) as well as 12 pharmaceuticals. SMR were able to remove 98% of spiked E2, 80% of EE2, 87% of BPA, and up to 97% of DES from water. For a 0.5ppm mixture of E2, EE2, E1, BPA and DES, the minimum removal was 24% (E2) and the maximum was 49% (DES). They were also able to remove the pharmaceuticals from deionized water and wastewater. Overall, SMR are a promising advanced treatment for removal of both EDCs and pharmaceuticals. Copyright © 2016. Published by Elsevier B.V.

  9. Regional differences in organic composition of submicron and single particles during INTEX-B 2006

    Directory of Open Access Journals (Sweden)

    D. A. Day

    2009-03-01

    Full Text Available Organic functional group and elemental concentrations were measured with Fourier transform infrared (FTIR spectroscopy and X-ray fluorescence (XRF from an aircraft platform as part of the Intercontinental Chemical Transport Experiment – Phase B (INTEX-B conducted over the Eastern Pacific and Western North America. Single particle spectra were obtained using scanning transmission X-ray microscopy-near edge X-ray absorption fine structure spectrometry (STXM-NEXAFS. Organic mass (OM concentrations ranged from 1 to 7 μg m−3 and averaged 2.4–4.1 μg m−3. Alkane functional groups were the largest fraction of OM, averaging 1.9–2.1 μg m−3 or 50–76% of OM. Alcohol functional groups comprised the second largest fraction of OM (0.35–0.39 μg m−3, 9–14%. Organic and elemental concentrations are compared within and among geographical air mass regions: "Pacific" free troposphere, "Continental" free troposphere, "Seattle" metropolitan region, and the California "Central Valley". OM concentrations were highest and most variable in the Central Valley (3.5±2 μg m−3. Alcohol functional group concentrations were highest in the Continental and Central Valley and lowest in the Pacific and Seattle air masses. Oxygen-to-carbon ratios were relatively constant in the Central Valley but variable for the Continental air masses. Most elemental concentrations did not show large variations among or within air mass categories. Overall, the OM concentrations showed greater variability within air mass categories as compared to averages among them, suggesting sampled air mass regions included a variety of sources, processing, and losses of organic aerosol. Single particle spectra obtained by STXM-NEXAFS were classified into metaclasses associated with different sources and atmospheric processing. Particles with spectra indicative of secondary organic aerosol production and combustion sources were

  10. Submicron particles in an urban atmosphere: A study of optical size distributions—I

    Science.gov (United States)

    Trier, A.

    Atmospheric particle size distributions and number concentrations in the 0.065-0.900 μm diameter range have been observed at a site in the city of Santiago de Chile from June 1992 to December 1994 by means of an active light-scattering spectrometer; such information was not previously available. Observed concentrations ranged from 2000 to 16,000 per cm 3. Geometric mean diameters (GMD) for the distributions ranged from 0.100 to 0.160 μm, while geometric standard deviations (GSD) ranged from 1.34 to 1.65 and volume-weighted mean diameters (VWD) ranged from 0.18 to 0.42 μm Scatter plots and time-ordered sequences for these parameters are shown as well as Spearman rank-difference correlations. Examples of the particle-number concentration distributions and of daily concentration trends are displayed and discussed.

  11. Dynamics of Dissolved Organic Matter and Microbes in Seawater through Sub-Micron Particle Size Analyses

    Digital Repository Service at National Institute of Oceanography (India)

    Goes, J.I.; Balch, W.M.; Vaughn, J.M.; Gomes, H.R.

    , 1997). In view of the above, understanding the processes regulating the dynamics and distribution of DOM in seawater, assumes tremendous importance for global biogeochemistry and climate change studies. Phytoplankton are the primary source of oceanic.... The exact relationship between the lift force and the channel flow velocity is not well- characterized and calibrations with standard monodispersed particles (>1?m) are necessary to calibrate an FFFF fractogram into a size distribution plot. The FFFF...

  12. Noise Removal with Maintained Spatial Resolution in Raman Images of Cells Exposed to Submicron Polystyrene Particles

    Directory of Open Access Journals (Sweden)

    Linnea Ahlinder

    2016-04-01

    Full Text Available The biodistribution of 300 nm polystyrene particles in A549 lung epithelial cells has been studied with confocal Raman spectroscopy. This is a label-free method in which particles and cells can be imaged without using dyes or fluorescent labels. The main drawback with Raman imaging is the comparatively low spatial resolution, which is aggravated in heterogeneous systems such as biological samples, which in addition often require long measurement times because of their weak Raman signal. Long measurement times may however induce laser-induced damage. In this study we use a super-resolution algorithm with Tikhonov regularization, intended to improve the image quality without demanding an increased number of collected pixels. Images of cells exposed to polystyrene particles have been acquired with two different step lengths, i.e., the distance between pixels, and compared to each other and to corresponding images treated with the super-resolution algorithm. It is shown that the resolution after application of super-resolution algorithms is not significantly improved compared to the theoretical limit for optical microscopy. However, to reduce noise and artefacts in the hyperspectral Raman images while maintaining the spatial resolution, we show that it is advantageous to use short mapping step lengths and super-resolution algorithms with appropriate regularization. The proposed methodology should be generally applicable for Raman imaging of biological samples and other photo-sensitive samples.

  13. Production and characterization of submicron hematite (α−Fe{sub 2}O{sub 3}) particles by ultrasonic spray pyrolysis method

    Energy Technology Data Exchange (ETDEWEB)

    Kırcı, Burak; Ebin, Burçak; Gürmen, Sebahattin [Department of Metallurgical and Materials Engineering, Istanbul Technical University Istanbul (Turkey)

    2013-12-16

    The ultrasonic spray pyrolysis (USP) method has been used to prepare submicron hematite (α−Fe{sub 2}O{sub 3}) particles using two different industrial pickling solutions of iron chloride (41 g/L FeCl{sub 2} and 54 g/L FeCl{sub 3}) Particles were obtained by thermal decomposition of generated aerosols from precursor solutions using 1.7 MHz ultrasonic atomizer. Reaction temperature was set up at 800 °C and aerosol droplets were carried into the heated zone by 0.7 L/min air flow rate. X-Ray Diffraction (XRD) studies were used to determine the crystal structure and crystallite size of the particles. Results indicate that patterns correspond to hematite phase with rhombohedral crystal structure (space group: R3c). The crystallite sizes of particles prepared from FeCl{sub 2} and FeCl{sub 3} solutions that were calculated from Scherrer equation are 59 and 33 nm, respectively. Scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) investigations give detailed information about particle size, morphology and composition. SEM micrographs show that hematite nanoparticles aggregate and formed spherical secondary particles in submicron range.

  14. Preparation of submicron-sized spherical particles of gold using laser-induced melting in liquids and low-toxic stabilizing reagent

    Energy Technology Data Exchange (ETDEWEB)

    Tsuji, T., E-mail: tkstsuji@riko.shimane-u.ac.jp [Interdisciplinary Graduate School of Science and Engineering, Shimane University, 1060 Nishikawatsu-Cho, Matsue (Japan); Higashi, Y.; Tsuji, M. [Interdisciplinary Graduate School of Engineering Science, Kyushu University, 6-1 Kasuga-Koen, Kasuga (Japan); Ishikawa, Y. [National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba, Ibaraki (Japan); Koshizaki, N. [Interdisciplinary Graduate School of Engineering, Hokkaido University, Kita13 Nishi8, Kita-Ku, Sapporo, Hokkaido (Japan)

    2015-09-01

    Highlights: • Submicron-sized spherical particles of gold were prepared using laser irradiation for the source gold nanoparticles stabilized by NaCl. • The source gold nanoparticles agglomeration was controlled both by the NaCl concentration of and by laser irradiation. • The formation process and the laser-fluence dependence of the particle size of gold nanoparticles in NaCl solutions differs from those in citrate solutions. • We revealed that properties of ligands are significantly important to prepare submicron-sized spherical particles and to control their size. - Abstract: Laser-induced melting in liquids (LIML) was applied to prepare spherical submicron-sized particles of gold (AuSMPs) from gold nanoparticles (AuNPs) stabilized using NaCl. Because undesirable byproducts, which might be generated when organic reagents such as citrate are used as the stabilizing reagent, are not generated from NaCl by laser irradiation, AuSMPs fabricated from AuNPs stabilized by NaCl will be low toxic. The AuSMPs were obtained by laser irradiation of the source AuNPs in NaCl solutions stabilized by NaCl at the proper concentration. Similar to the preparation of AuSMPs from AuNPs stabilized by citrate, the agglomeration of the source AuNPs, which is necessary to obtain AuSMPs, was controlled both by the NaCl concentration and by laser irradiation. However, the formation process and the laser-fluence dependence of the particle size of AuSMPs differed for various NaCl solutions and citrate solutions.

  15. Stability of lipid encapsulated ferulic acid particles

    Science.gov (United States)

    Encapsulation of bioactive compounds by a solid lipid matrix provides stability and a mechanism for controlled release in formulated products. Phenolic compounds exhibit antioxidant and antimicrobial activities and have applications as functional food and feed additives. Ferulic acid, a common pheno...

  16. Chemical characterization of submicron aerosol and particle growth events at a national background site (3295 m a.s.l. in the Tibetan Plateau

    Directory of Open Access Journals (Sweden)

    W. Du

    2015-05-01

    Full Text Available Atmospheric aerosols exert highly uncertain impacts on radiative forcing and also have detrimental effects on human health. While aerosol particles are widely characterized in megacities in China, aerosol composition, sources and particle growth in rural areas in the Tibetan Plateau remain less understood. Here we present the results from an autumn study that was conducted from 5 September to 15 October 2013 at a national background monitoring station (3295 m a.s.l. in the Tibetan Plateau. The submicron aerosol composition and particle number size distributions were measured in situ with an Aerodyne Aerosol Chemical Speciation Monitor (ACSM and a Scanning Mobility Particle Sizer (SMPS. The average mass concentration of submicron aerosol (PM1 is 11.9 μg m−3 (range: 1.0–78.4 μg m−3 for the entire study, which is much lower than those observed at urban and rural sites in eastern China. Organics dominated PM1 on average accounting for 43%, followed by sulfate (28% and nitrate (1%. Positive matrix factorization analysis of ACSM organic aerosol (OA mass spectra identified an oxygenated OA (OOA and a biomass burning OA (BBOA. The OOA dominated OA composition accounting for 85% on average, 17% of which was inferred from aged BBOA. The BBOA contributed a considerable fraction of OA (15% due to the burning of cow dung and straws in September. New particle formation and growth events were frequently observed (80% of time throughout the study. The average particle growth rate is 2.0 nm h−1 (range: 0.8–3.2 nm h−1. By linking the evolution of particle number size distribution to aerosol composition, we found an elevated contribution of organics during particle growth periods and also a positive relationship between the growth rate and the fraction of OOA in OA, which potentially indicates an important role of organics in particle growth in the Tibetan Plateau.

  17. Toward Quantifying the Mass-Based Hygroscopicity of Individual Submicron Atmospheric Aerosol Particles with STXM/NEXAFS and SEM/EDX

    Science.gov (United States)

    Yancey Piens, D.; Kelly, S. T.; OBrien, R. E.; Wang, B.; Petters, M. D.; Laskin, A.; Gilles, M. K.

    2014-12-01

    The hygroscopic behavior of atmospheric aerosols influences their optical and cloud-nucleation properties, and therefore affects climate. Although changes in particle size as a function of relative humidity have often been used to quantify the hygroscopic behavior of submicron aerosol particles, it has been noted that calculations of hygroscopicity based on size contain error due to particle porosity, non-ideal volume additivity and changes in surface tension. We will present a method to quantify the hygroscopic behavior of submicron aerosol particles based on changes in mass, rather than size, as a function of relative humidity. This method results from a novel experimental approach combining scanning transmission x-ray microscopy with near-edge x-ray absorption fine spectroscopy (STXM/NEXAFS), as well as scanning electron microscopy with energy dispersive x-ray spectroscopy (SEM/EDX) on the same individual particles. First, using STXM/NEXAFS, our methods are applied to aerosol particles of known composition ‒ for instance ammonium sulfate, sodium bromide and levoglucosan ‒ and validated by theory. Then, using STXM/NEXAFS and SEM/EDX, these methods are extended to mixed atmospheric aerosol particles collected in the field at the DOE Atmospheric Radiation Measurement (ARM) Climate Research Facility at the Southern Great Planes sampling site in Oklahoma, USA. We have observed and quantified a range of hygroscopic behaviors which are correlated to the composition and morphology of individual aerosol particles. These methods will have implications for parameterizing aerosol mixing state and cloud-nucleation activity in atmospheric models.

  18. Quantifying lipid contents in enveloped virus particles with plasmonic nanoparticles.

    Science.gov (United States)

    Feizpour, Amin; Yu, Xinwei; Akiyama, Hisashi; Miller, Caitlin M; Edmans, Ethan; Gummuluru, Suryaram; Reinhard, Björn M

    2015-04-01

    Phosphatidylserine (PS) and monosialotetrahexosylganglioside (GM1 ) are examples of two host-derived lipids in the membrane of enveloped virus particles that are known to contribute to virus attachment, uptake, and ultimately dissemination. A quantitative characterization of their contribution to the functionality of the virus requires information about their relative concentrations in the viral membrane. Here, a gold nanoparticle (NP) binding assay for probing relative PS and GM1 lipid concentrations in the outer leaflet of different HIV-1 and Ebola virus-like particles (VLPs) using sample sizes of less than 3 × 10(6) particles is introduced. The assay evaluates both scattering intensity and resonance wavelength, and determines relative NP densities through plasmon coupling as a measure for the target lipid concentrations in the NP-labeled VLP membrane. A correlation of the optical observables with absolute lipid contents is achieved by calibration of the plasmon coupling-based methodology with unilamellar liposomes of known PS or GM1 concentration. The performed studies reveal significant differences in the membrane of VLPs that assemble at different intracellular sites and pave the way to an optical quantification of lipid concentration in virus particles at physiological titers.

  19. The influence of environmental drivers on the enrichment of organic carbon in the sea surface microlayer and in submicron aerosol particles – measurements from the Atlantic Ocean

    Directory of Open Access Journals (Sweden)

    Manuela van Pinxteren

    2017-06-01

    Full Text Available The export of organic matter from ocean to atmosphere represents a substantial carbon flux in the Earth system, yet the impact of environmental drivers on this transfer is not fully understood. This work presents dissolved and particulate organic carbon (DOC, POC concentrations, their enrichment factors in the sea surface microlayer (SML, and equivalent measurements in marine aerosol particles across the Atlantic Ocean. DOC concentrations averaged 161 ± 139 μmol L–1 (n = 78 in bulk seawater and 225 ± 175 μmol L–1 (n = 79 in the SML; POC concentrations averaged 13 ± 11 μmol L–1 (n = 80 and 17 ± 10 μmol L–1 (n = 80, respectively. High DOC and POC enrichment factors were observed when samples had low concentrations, and lower enrichments when concentrations were high. The impacts of wind speed and chlorophyll-a levels on concentrations and enrichment of DOC and POC in seawater were insignificant. In ambient submicron marine aerosol particles the concentration of water-soluble organic carbon was approximately 0.2 μg m–3. Water-insoluble organic carbon concentrations varied between 0.01 and 0.9 μg m–3, with highest concentrations observed when chlorophyll-a concentrations were high. Concerted measurements of bulk seawater, the SML and aerosol particles enabled calculation of enrichment factors of organic carbon in submicron marine ambient aerosols, which ranged from 103 to 104 during periods of low chlorophyll-a concentrations and up to 105 when chlorophyll-a levels were high. The results suggest that elevated local biological activity enhances the enrichment of marine-sourced organic carbon on aerosol particles. However, implementation of the results in source functions based on wind speed and chlorophyll-a concentrations underestimated the organic fraction at low biological activity by about 30%. There may be additional atmospheric and oceanic parameters to consider for accurately predicting organic fractions on aerosol

  20. Source apportionment of fine PM and sub-micron particle number concentrations at a regional background site in the western Mediterranean: a 2.5 year study

    Science.gov (United States)

    Cusack, M.; Pérez, N.; Pey, J.; Alastuey, A.; Querol, X.

    2013-05-01

    The chemical composition and sources of ambient fine particulate matter (PM1) over a period of 2.5 years for a regional background site in the western Mediterranean are presented in this work. Furthermore, sub-micron particle number concentrations and the sources of these particles are also presented. The mean PM1 concentration for the measurement period was 8.9 μg m-3, with organic matter (OM) and sulphate comprising most of the mass (3.2 and 1.5 μg m-3 respectively). Six sources were identified in PM1 by Positive Matrix Factorisation (PMF): secondary organic aerosol, secondary nitrate, industrial, traffic + biomass burning, fuel oil combustion and secondary sulphate. Typically anthropogenic sources displayed elevated concentrations during the week with reductions at weekends. Nitrate levels were elevated in winter and negligible in summer, whereas secondary sulphate levels underwent a contrasting seasonal evolution with highest concentrations in summer, similar to the fuel oil combustion source. The SOA source was influenced by episodes of sustained pollution as a result of anticyclonic conditions occurring during winter, giving rise to thermal inversions and the accumulation of pollutants in the mixing layer. Increased levels in summer were owing to higher biogenic emissions and regional recirculation of air masses. The industrial source decreased in August due to decreased emissions during the vacation period. Increases in the traffic + biomass burning source were recorded in January, April and October, which were attributed to the occurrence of the aforementioned pollution episodes and local biomass burning emission sources, which include agriculture and domestic heating systems. Average particle number concentrations (N9-825 nm) from 5/11/2010 to 01/06/2011 and from 15/10/2011 to 18/12/2011 reached 3097 cm-3. Five emission sources of particle of sub-micron particles were determined by Principal Component Analysis (PCA); industrial + traffic + biomass

  1. The heterogeneous reaction of hydroxyl radicals with sub-micron squalane particles: a model system for understanding the oxidative aging of ambient aerosols

    Science.gov (United States)

    Smith, J. D.; Kroll, J. H.; Cappa, C. D.; Che, D. L.; Liu, C. L.; Ahmed, M.; Leone, S. R.; Worsnop, D. R.; Wilson, K. R.

    2009-05-01

    The heterogeneous reaction of OH radicals with sub-micron squalane particles, in the presence of O2, is used as a model system to explore the fundamental chemical mechanisms that control the oxidative aging of organic aerosols in the atmosphere. Detailed kinetic measurements combined with elemental mass spectrometric analysis reveal that the reaction proceeds sequentially by adding an average of one oxygenated functional group per reactive loss of squalane. The reactive uptake coefficient of OH with squalane particles is determined to be 0.3±0.07 at an average OH concentration of ~1×1010 molecules cm-3. Based on a comparison between the measured particle mass and model predictions it appears that significant volatilization of a reduced organic particle would be extremely slow in the real atmosphere. However, as the aerosols become more oxygenated, volatilization becomes a significant loss channel for organic material in the particle-phase. Together these results provide a chemical framework in which to understand how heterogeneous chemistry transforms the physiochemical properties of particle-phase organic matter in the troposphere.

  2. The heterogeneous reaction of hydroxyl radicals with sub-micron squalane particles: a model system for understanding the oxidative aging of ambient aerosols

    Directory of Open Access Journals (Sweden)

    J. D. Smith

    2009-02-01

    Full Text Available The heterogeneous reaction of OH radicals with sub-micron squalane particles, in the presence of O2, is used as a model system to explore the fundamental chemical mechanisms that control the oxidative aging of organic aerosols in the atmosphere. Detailed kinetic measurements combined with elemental mass spectrometric analysis reveal that the reaction proceeds sequentially by adding an average of one oxygenated functional group per reactive loss of squalane. The reactive uptake coefficient of OH with squalane particles is determined to be 0.3±0.07 at an average OH concentration of ~1×1010 molecules·cm−3. Based on a comparison between the measured particle mass and model predictions it appears that significant volatilization of a reduced organic particle would be extremely slow in the real atmosphere. However, as the aerosols become more oxygenated, volatilization becomes a significant loss channel for organic material in the particle phase. Together these results provide a chemical framework in which to understand how heterogeneous chemistry transforms the physiochemical properties of particle phase organic matter in the troposphere.

  3. The heterogeneous reaction of hydroxyl radicals with sub-micron squalane particles: a model system for understanding the oxidative aging of ambient aerosols

    Directory of Open Access Journals (Sweden)

    J. D. Smith

    2009-05-01

    Full Text Available The heterogeneous reaction of OH radicals with sub-micron squalane particles, in the presence of O2, is used as a model system to explore the fundamental chemical mechanisms that control the oxidative aging of organic aerosols in the atmosphere. Detailed kinetic measurements combined with elemental mass spectrometric analysis reveal that the reaction proceeds sequentially by adding an average of one oxygenated functional group per reactive loss of squalane. The reactive uptake coefficient of OH with squalane particles is determined to be 0.3±0.07 at an average OH concentration of ~1×1010 molecules cm−3. Based on a comparison between the measured particle mass and model predictions it appears that significant volatilization of a reduced organic particle would be extremely slow in the real atmosphere. However, as the aerosols become more oxygenated, volatilization becomes a significant loss channel for organic material in the particle-phase. Together these results provide a chemical framework in which to understand how heterogeneous chemistry transforms the physiochemical properties of particle-phase organic matter in the troposphere.

  4. Source apportionment of fine PM and sub-micron particle number concentrations at a regional background site in the western Mediterranean: a 2.5 yr study

    Science.gov (United States)

    Cusack, M.; Pérez, N.; Pey, J.; Alastuey, A.; Querol, X.

    2013-02-01

    The chemical composition and sources of ambient fine particulate matter (PM1) over a period of 2.5 yr for a regional background site in the western Mediterranean are presented in this work. Major components (such as SO12-, NO3-, NH4+, organic and elemental carbon) and trace elements were analysed and the emission sources affecting PM1 were determined using Positive Matrix Factorisation (PMF). Furthermore, sub-micron particle number concentrations and the sources of these particles are also presented. Sources of sub-micron particles were determined by Principal Component Analysis (PCA). The mean PM1 concentration for the measurement period was 8.9 μg m-3, with organic matter (OM) and sulphate comprising most of the mass (3.2 and 1.5 μg m-3). A clear seasonal variation was recorded with higher PM1 concentrations in summer (11.2 μg m-3) compared to winter (6.6 μg m-3). This summer increase was due to elevated levels of sulphate and OM. Six sources were identified by PMF: secondary organic aerosol, secondary nitrate, industrial, traffic + biomass burning, fuel oil combustion and secondary sulphate. The daily variations of these sources were also determined, whereby the typically anthropogenic sources displayed elevated concentrations during the week with reductions at weekends. Nitrate levels were elevated in winter and negligible in summer, whereas secondary sulphate levels underwent a contrasting seasonal evolution with highest concentrations in summer, similar to the fuel oil combustion source. The SOA source was influenced by episodes of sustained pollution as a result of anticyclonic conditions occurring during winter, giving rise to thermal inversions and the accumulation of pollutants in the mixing layer. Increased levels in summer were owing to higher biogenic emissions and regional recirculation of air masses. The industrial source decreased in August due to decreased emissions during the vacation period. Increases in the traffic + biomass burning source

  5. Mixing state of individual submicron carbon-containing particles during spring and fall seasons in urban Guangzhou, China: a case study

    Directory of Open Access Journals (Sweden)

    G. Zhang

    2013-05-01

    Full Text Available Growing evidence suggests that the size-resolved mixing state of carbon-containing particles is very critical in determining their optical properties, atmospheric lifetime, and impact on the environment. However, still little is known about the mixing state of particles in the urban area of the Pearl River Delta (PRD region, China. To investigate the mixing state of submicron carbon-containing particles, measurements were carried out during spring and fall periods of 2010 using a single-particle aerosol mass spectrometer (SPAMS. Approximately 700 000 particles for each period were detected. This is the first report on the size-resolved mixing state of carbon-containing particles by direct observations in the PRD region. Cluster analysis of single-particle mass spectra was applied to identify carbon-containing particle classes. These classes represented ~80% and ~90% of all the detected particles for spring and fall periods, respectively. Carbon-containing particle classes mainly consisted of biomass/biofuel burning particles (Biomass, organic carbon (OC, fresh elemental carbon (EC-fresh, internally mixed OC and EC (ECOC, internally mixed EC with sulfate (EC-Sulfate, vanadium-containing ECOC (V-ECOC, and amines-containing particles (Amine. In spring, the top three ranked carbon-containing particle classes were ECOC (26.1%, Biomass (23.6% and OC (10%, respectively. However, the fraction of Biomass particles increased remarkably and predominated (61.0%, while the fraction of ECOC (3.0% and V-ECOC (0.1% significantly decreased in fall. To highlight the influence of monsoon on the properties of carbon-containing particles in urban Guangzhou, their size distributions, mixing state, and aerosol acidity were compared between spring and fall seasons. In addition, a case study was also performed to investigate how the formation of fog and haze influenced the mixing state of carbon-containing particles. These results could improve our understanding of the

  6. Mixing state of individual submicron carbon-containing particles during spring and fall seasons in urban Guangzhou, China: a case study

    Science.gov (United States)

    Zhang, G.; Bi, X.; Li, L.; Chan, L. Y.; Li, M.; Wang, X.; Sheng, G.; Fu, J.; Zhou, Z.

    2013-05-01

    Growing evidence suggests that the size-resolved mixing state of carbon-containing particles is very critical in determining their optical properties, atmospheric lifetime, and impact on the environment. However, still little is known about the mixing state of particles in the urban area of the Pearl River Delta (PRD) region, China. To investigate the mixing state of submicron carbon-containing particles, measurements were carried out during spring and fall periods of 2010 using a single-particle aerosol mass spectrometer (SPAMS). Approximately 700 000 particles for each period were detected. This is the first report on the size-resolved mixing state of carbon-containing particles by direct observations in the PRD region. Cluster analysis of single-particle mass spectra was applied to identify carbon-containing particle classes. These classes represented ~80% and ~90% of all the detected particles for spring and fall periods, respectively. Carbon-containing particle classes mainly consisted of biomass/biofuel burning particles (Biomass), organic carbon (OC), fresh elemental carbon (EC-fresh), internally mixed OC and EC (ECOC), internally mixed EC with sulfate (EC-Sulfate), vanadium-containing ECOC (V-ECOC), and amines-containing particles (Amine). In spring, the top three ranked carbon-containing particle classes were ECOC (26.1%), Biomass (23.6%) and OC (10%), respectively. However, the fraction of Biomass particles increased remarkably and predominated (61.0%), while the fraction of ECOC (3.0%) and V-ECOC (0.1%) significantly decreased in fall. To highlight the influence of monsoon on the properties of carbon-containing particles in urban Guangzhou, their size distributions, mixing state, and aerosol acidity were compared between spring and fall seasons. In addition, a case study was also performed to investigate how the formation of fog and haze influenced the mixing state of carbon-containing particles. These results could improve our understanding of the

  7. Submicron sized ultra-high molecular weight polyethylene wear particle analysis from revised SB Charité III total disc replacements.

    Science.gov (United States)

    Punt, Ilona; Baxter, Ryan; van Ooij, André; Willems, Paul; van Rhijn, Lodewijk; Kurtz, Steven; Steinbeck, Marla

    2011-09-01

    Submicron sized particles are frequently observed in retrieved total hip and knee periprosthetic tissues and appear to be critical in the activation of the phagocytic inflammatory response. In this paper the concentration, size and shape of ultra-high molecular weight polyethylene (UHMWPE) wear particles between 0.05 and 2.00μm were determined after isolation from periprosthetic tissues from retrieved lumbar SB Charité III total disc replacements (TDR) using scanning electron microscopy (SEM). For comparison, UHMWPE wear particles were isolated from γ-radiation-air sterilized total hip arthroplasty (THA) revision tissues. The mean concentration of UHMWPE particles in TDR tissues was 1.6×10(9)g(-1)tissue (range 1.3-2.0), which was significantly lower than the concentration of 2.3×10(9)g(-1) THA revision tissue (range 1.8-3.2) (P=0.03). The mean particle size (equivalent circular diameter: TDR, 0.46μm; THA 0.53μm, P=0.60) and mean shape were comparable between TDR and THA (aspect ratio: TDR, 1.89; THA, 1.99, P=0.35; roundness: TDR, 0.58; THA, 0.56, P=0.35). However, the TDR particles tended to be smaller and more round. Although no correlations were found between visible damage to the UHMWPE core and the concentration or shape of the UHMWPE particles, a positive correlation was found between increasing particle size and increasing rim penetration of the TDR core (P=0.04). The presence of UHMWPE particles of similar size and shape in TDR tissue, albeit lower in concentration, might explain why, unlike THA, pain rather than osteolysis is the major reason for revision surgery. Copyright © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  8. Interaction measurement of particles bound to a lipid membrane

    Science.gov (United States)

    Sarfati, Raphael; Dufresne, Eric

    2015-03-01

    The local shape and dynamics of the plasma membrane play important roles in many cellular processes. Local membrane deformations are often mediated by the adsorption of proteins (notably from the BAR family), and their subsequent self-assembly. The emerging hypothesis is that self-assembly arises from long-range interactions of individual proteins through the membrane's deformation field. We study these interactions in a model system of micron-sized colloidal particles adsorbed onto a lipid bilayer. We use fluorescent microscopy, optical tweezers and particle tracking to measure dissipative and conservative forces as a function of the separation between the particles. We find that particles are driven together with forces of order 100 fN and remain bound in a potential well with a stiffness of order 100 fN/micron.

  9. A Variational Approach to Particles in Lipid Membranes

    Science.gov (United States)

    Elliott, Charles M.; Gräser, Carsten; Hobbs, Graham; Kornhuber, Ralf; Wolf, Maren-Wanda

    2016-11-01

    A variety of models for the membrane-mediated interaction of particles in lipid membranes, mostly well-established in theoretical physics, is reviewed from a mathematical perspective. We provide mathematically consistent formulations in a variational framework, relate apparently different modelling approaches in terms of successive approximation, and investigate existence and uniqueness. Numerical computations illustrate that the new variational formulations are directly accessible to effective numerical methods.

  10. A multinuclear solid-state magnetic resonance study of the interactions between the inorganic and organic coatings of BaSO4 submicronic particles.

    Science.gov (United States)

    Borsacchi, S; Geppi, M; Veracini, C A; Lazzeri, A; Di Cuia, F; Geloni, C

    2008-01-01

    Silica-coated BaSO4 submicronic particles, modified on the surface by treatment with stearic acid, have been characterized by means of 29Si, 13C, and 1H magic-angle-spinning (MAS) high-resolution techniques, and low-resolution 1H-FID analysis. Two types of adsorbed water were identified; adsorbed either inside or on the surface of BaSO4, most of the latter being removed by the silica coating. Evidences of silica-stearic acid interactions were found involving either carboxylic acid or carboxylate functional groups, and occurring by means of hydrogen and/or covalent bonds. Stearic acid was present as monolayer only, its chain being mostly rigid, even though a small fraction was subjected to fast inter-conformational motions.

  11. Submicron aerosols at thirteen diversified sites in China: size distribution, new particle formation and corresponding contribution to cloud condensation nuclei production

    Directory of Open Access Journals (Sweden)

    J. F. Peng

    2014-06-01

    Full Text Available Understanding the particle number size distributions in diversified atmospheric environments is important in order to design mitigation strategies related to submicron particles and their effect on regional air quality, haze and human health. In this study, we conducted 15 different field measurement campaigns, each one-month long, between 2007 and 2011 at 13 individual sites in China. These were 5 urban sites, 4 regional sites, 3 coastal/background sites and one ship cruise measurement along eastern coastline of China. Size resolved particles were measured in the 15–600 nm size range. The median particle number concentrations (PNC were found to vary in the range of 1.1–2.2 × 104 cm−3 at urban sites, 0.8–1.5 × 104 cm−3 at regional sites, 0.4–0.6 × 104 cm−3 at coastal/background sites, and 0.5 × 104 cm−3 during cruise measurements. Peak diameters at each of these sites varied greatly from 24 nm to 115 nm. Particles in the 15–25 nm (nucleation mode, 25–100 nm (Aitken mode and 100–600 nm (accumulation mode range showed different characteristics at each of the studied sites, indicating the features of primary emissions and secondary formation in these diversified atmospheric environments. Diurnal variations show a build-up of accumulation mode particles belt at regional sites, suggesting the contribution of regional secondary aerosol pollution. Frequencies of new particle formation (NPF events were much higher at urban and regional sites than at coastal sites and cruise measurement. The average growth rates (GRs of nucleation mode particles were 8.0–10.9 nm h−1 at urban sites, 7.4–13.6 nm h−1 at regional sites and 2.8–7.5 nm h−1 at both coastal and cruise measurement sites. The high gaseous precursors and strong oxidation at urban and regional sites not only favored the formation of particles, but also accelerated the growth rate of the nucleation mode particles. No significant difference in condensation sink

  12. Separation of submicron particles from biofuel combustion with flue gas condensation or wet condensing electrostatic precipitator. Analysis of possibilities; Avskiljning av submikrona partiklar vid biobraenslefoerbraenning med roekgaskondensering eller kondenserande vaata elfilter. Analys av moejligheterna

    Energy Technology Data Exchange (ETDEWEB)

    Roennbaeck, Marie; Gustavsson, Lennart [Swedish National Testing and Research Inst., Boraas (Sweden)

    2006-11-15

    Dust particles in flue gas larger than 1 {mu}m are well separated by conventional techniques, while submicron particles are poorly separated. As the use of biofuels with high ash content is increasing, as well as knowledge about negative health effects from inhalation of submicron particles, the interest for reduction of emissions of submicron particles will probably increase. The aim of this project is to investigate possible techniques for separation of submicron particles during flue gas condensation through modification of conventional technique, or with available techniques not usually used with combustion of biofuels, e.g. a wet electrostatic precipitator. Mechanisms for separation of dust particles are briefly described. Cyclones separates particles larger than about 1 {mu}m. Fabric filters separates all particles sizes, but the efficiency reduces as the size reduces. In flue gas condensers and scrubbers the speed and size of water droplets are important for the reduction efficiency. Dry electrostatic precipitators work for all particle sizes, but with reduced efficiency for sizes between 0.1 and 3 {mu}m. Wet electrostatic precipitators separates submicron particles much better. One reason for this is that the potential between the electrodes can be higher. Among conventional flue gas condensers and scrubbers there are two types that, properly designed, can separate submicron particles, namely 'type venturi scrubbers', i.e. a scrubber where a high flue gas velocity is used to form many, small water droplets by friction forces in a nozzle, and 'type scrubber with nozzles', i.e. a scrubber where nozzles supply droplets to the flue gas. For a scrubber with nozzles, the falling velocity of the droplets must be lower and the size smaller than is common today. Also the wet electrostatic precipitator separates submicron particles with high efficiency. They are used today mainly for problematic particles, e.g. sticky or corrosive ones, or for

  13. Apolipoprotein B-containing lipoprotein particle assembly: Lipid capacity of the nascent lipoprotein particle

    Energy Technology Data Exchange (ETDEWEB)

    Manchekar, Medha; Forte, Trudy M.; Datta, Geeta; Richardson, Paul E.; Segrest, Jere P.; Dashti, Nassrin

    2003-12-01

    We previously proposed that the N-terminal 1000 residue {beta}{alpha}{sub 1} domain of apolipoprotein B (apoB) forms a bulk lipid pocket homologous to that of lamprey lipovitellin (LV). In support of this ''lipid pocket'' hypothesis, apoB:1000 (residues 1-1000) was shown to be secreted by a stable transformant of McA-RH7777 cells as a monodisperse particle with HDL{sub 3} density and Stokes diameter of 112 {angstrom}. In contrast, apoB:931 (residues 1-931), missing only 69 residues of the sequence homologous to LV, was secreted as a particle considerably more dense than HDL with Stokes diameter of 110 {angstrom}. The purpose of the present study was to determine the stoichiometry of the lipid component of the apoB:931 and apoB:1000 particles. This was accomplished by metabolic labeling of cells with either [{sup 14}C]oleic acid or [{sup 3}H]glycerol followed by immunoprecipitation (IP) or nondenaturing gradient gel electrophoresis (NDGGE) of secreted lipoproteins and by immunoaffinity chromatography of secreted unlabeled lipoproteins. The [{sup 3}H]-labeled apoB:1000-containing particles, isolated by NDGGE, contained 50 phospholipids (PL) and 11 triacylglycerols (TAG) molecules per particle. In contrast, apoB:931-containing particles contained only a few molecules of PL and were devoid of TAG. The unlabeled apoB:1000-containing particles isolated by immunoaffinity chromatography and analyzed for lipid mass, contained 56 PL, 8 TAG, and 7 cholesteryl ester molecules per particle. The surface:core lipid ratio of apoB:1000-containing particles was approximately 4:1 and was not affected by incubation of cells with oleate. Although small amounts of microsomal triglyceride transfer protein (MTP) were associated with apoB:1000-containing particles, it never approached a 1:1 molar ratio of MTP to apoB. These results support a model in which: (1) the first 1000 amino acid residues of apoB are competent to complete the ''lipid pocket

  14. Organic composition of single and submicron particles in different regions of western North America and the eastern Pacific during INTEX-B 2006

    Directory of Open Access Journals (Sweden)

    D. A. Day

    2009-08-01

    Full Text Available Single particles were collected from an aircraft platform as part of the Intercontinental Chemical Transport Experiment – Phase B (INTEX-B conducted over the eastern Pacific and western North America. Single particle spectra were obtained using scanning transmission X-ray microscopy-near edge X-ray absorption fine structure spectroscopy (STXM-NEXAFS. Bulk submicron particles were also collected and organic functional group and elemental concentrations were quantified with Fourier transform infrared (FTIR spectroscopy and X-ray fluorescence (XRF. Single particle spectra were classified into metaclasses associated with different sources and atmospheric processing. Particles with spectra indicative of secondary organic aerosol production and combustion sources were found at several locations and a range of altitudes. At lower altitudes, particles with spectra resembling soil dust and biomass burning fingerprints were commonly observed. The types of particle spectra most commonly observed aloft were similar to those observed during a previous study over the northwestern Pacific, indicating that long-range transport may have been an important particle source. Single particle spectra provided evidence that condensation and surface-limited oxidation contributed to particle growth. Organic mass (OM concentrations ranged from 1 to 7 μg m−3 and averaged 2.4–4.1 μg m−3. Alkane functional groups were the largest fraction of OM, averaging 1.9–2.1 μg m−3 or 50–76% of OM, followed by alcohol functional groups (0.35–0.39 μg m−3, 9–14%. Organic and elemental concentrations are compared within and among geographical air mass regions: "Pacific" free troposphere, "Continental" free troposphere, "Seattle" metropolitan region, and the California "Central Valley". OM concentrations were highest and most variable in the Central Valley (3.5±2 μg m−3. Oxygen-to-carbon ratios were

  15. Hygroscopicity of Chemically Aged, sub-micron Squalane Particles: On the Role of Size and Composition towards the Hygroscopicity Parameter κ

    Science.gov (United States)

    Harmon, C. W.; Smith, J. D.; Che, D. L.; Leone, S. R.; Wilson, K. R.

    2010-12-01

    Measurements presented herein explore cloud condensation nuclei (CCN) activity of sub-micron squalane particles chemically aged by hydroxyl radicals as a function of size and OH exposure. As squalane particles are exposed to OH radicals, size-selected 100, 150, and 200 nm particles monotically decrease in size with increasing OH exposure. Concurrently, their CCN derived hygroscopicity parameter values, κ, increase with OH exposure until saturating at 0.165 in the 100 nm data set, 0.140 in the 150 nm data set, and reach a maximum value of 0.075 in the 200 nm data set at the highest level of OH exposure. The critical super-saturation relative humidity (RH) at which CCN activity is achieved decreases initially with increasing OH exposure and then increases with OH exposure, most notably for the 100 nm data set and weakly with the 150 nm data set. Chemically aged squalane particles from the 200 nm data set show a monotonic decrease in critical super-saturation RH with all values of increasing OH exposure between 0.1-2.5 × 10^13 s molec./cc. The measured O:C ratios of 160 nm chemically aged squalane particles, which were reported previously, are compared to κ values by the CCN derived relationship reported in literature: κ = 0.30*O:C and reasonable agreement is attained in the size-selected 150 nm data set. These values are also compared with the hygroscopic growth factor derived relationship in literature: κ = 0.49*(O:C -0.25) and reasonable agreement is attained at O:C > 0.35.

  16. Study on Interface between Sub-micron Particles and Matrix n Al2O3p/Al Composites

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The microstructural characteristic of 1070Al matrix composites reinforced by 0.15 μm Al2O3 particles whose volume fraction was 40% was investigated by TEM and HREM. The results showed that the interface between the matrix and reinforcements was clean and bonded well, without any interfacial reaction products. There were some preferential crystallographic orientation relationships between Al matrix and Al2O3 particle because of the lattice imperfection on the surface of Al2O3 particles.

  17. Application of Sonication and Microwave Irradiation to Boost Continuous Fabrication of the Copper(II Oxide Sub-Micron Particles

    Directory of Open Access Journals (Sweden)

    Grzegorz Dzido

    2015-03-01

    Full Text Available Viability of the continuous-flow synthesis of rhomboidal copper(II oxide (CuO micro- and nanonoparticles was demonstrated. It has been shown that ultrasonic mixing of reactants, in the stage of Cu(OH2 synthesis, followed by microwave irradiation of the resulting suspension, gives very fine particles of CuO at high yield and within minutes. Near optimal parameters for the synthesis of fine particles in the continuous reactor were determined.

  18. Sub-micron particle behaviour and capture at an immuno-sensor surface in an ultrasonic standing wave.

    Science.gov (United States)

    Kuznetsova, Larisa A; Martin, Stacey P; Coakley, W Terence

    2005-12-15

    The capture of 200 nm biotinylated latex beads from suspensions of concentration 10(7) to 2.5 x 10(8) particle/ml on an immuno-coated surface of the acoustic reflector in an ultrasound standing wave (USW) resonator has been studied while the acoustic pathlength was less than one half wavelength (lambda/2). The particles were delivered to the reflector's surface by acoustically induced flow. The capture dependencies on suspension concentration, duration of experiments and acoustic pressure have been established at 1.09, 1.46 and 1.75 MHz. Five-fold capture increase has been obtained at 1.75 MHz in comparison to the control (no ultrasound) situation. The contrasting behaviours of 1, 0.5 and 0.2 mum fluorescent latex beads in a lambda/4 USW resonator at 1.46 MHz have been characterized. The particle movements were observed with an epi-fluorescent microscope and the velocities of the particles were measured by particle image velocimetry (PIV). The experiments showed that whereas the trajectories of 1 mum particles were mainly affected by the direct radiation force, 0.5 mum particles were influenced both by the radiation force and acoustic streaming. The 0.2 mum latex beads followed acoustic streaming in the chamber and were not detectably affected by the radiation force. The streaming-associated behaviour of the 200 nm particles has implications for enhanced immunocapture of viruses and macromolecules (both of which are also too small to experience significant acoustic radiation force).

  19. Identification and characterization of major lipid particle proteins of the yeast Saccharomyces cerevisiae.

    Science.gov (United States)

    Athenstaedt, K; Zweytick, D; Jandrositz, A; Kohlwein, S D; Daum, G

    1999-10-01

    Lipid particles of the yeast Saccharomyces cerevisiae were isolated at high purity, and their proteins were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Major lipid particle proteins were identified by mass spectrometric analysis, and the corresponding open reading frames (ORFs) were deduced. In silicio analysis revealed that all lipid particle proteins contain several hydrophobic domains but none or only few (hypothetical) transmembrane spanning regions. All lipid particle proteins identified by function so far, such as Erg1p, Erg6p, and Erg7p (ergosterol biosynthesis) and Faa1p, Faa4p, and Fat1p (fatty acid metabolism), are involved in lipid metabolism. Based on sequence homology, another group of three lipid particle proteins may be involved in lipid degradation. To examine whether lipid particle proteins of unknown function are also involved in lipid synthesis, mutants with deletions of the respective ORFs were constructed and subjected to systematic lipid analysis. Deletion of YDL193w resulted in a lethal phenotype which could not be suppressed by supplementation with ergosterol or fatty acids. Other deletion mutants were viable under standard conditions. Strains with YBR177c, YMR313c, and YKL140w deleted exhibited phospholipid and/or neutral lipid patterns that were different from the wild-type strain and thus may be further candidate ORFs involved in yeast lipid metabolism.

  20. Sub-micron atmospheric aerosols in the surroundings of Marseille and Athens: physical characterization and new particle formation

    Science.gov (United States)

    Petäjä, T.; Kerminen, V.-M.; Dal Maso, M.; Junninen, H.; Koponen, I. K.; Hussein, T.; Aalto, P. P.; Andronopoulos, S.; Robin, D.; Hämeri, K.; Bartzis, J. G.; Kulmala, M.

    2007-05-01

    The properties of atmospheric aerosol particles in Marseille and Athens were investigated. The studies were performed in Marseille, France, during July 2002 and in Athens, Greece, during June 2003. The aerosol size distribution and the formation and growth rates of newly formed particles were characterized using Differential Mobility Particle Sizers. Hygroscopic properties were observed using a Hygroscopic Tandem Differential Mobility Analyzer setup. During both campaigns, the observations were performed at suburban, almost rural sites, and the sites can be considered to show general regional background behavior depending on the wind direction. At both sites there were clear pattern for both aerosol number concentration and hygroscopic properties. Nucleation mode number concentration increased during the morning hours indicating new particle formation, which was observed during more than 30% of the days. The observed formation rate was typically more than 1 cm-3 s-1, and the growth rate was between 1.2-9.9 nm h-1. Based on hygroscopicity measurements in Athens, the nucleation mode size increase was due to condensation of both water insoluble and water soluble material. However, during a period of less anthropogenic influence, the growth was to a larger extent due to water insoluble components. When urban pollution was more pronounced, growth due to condensation of water soluble material dominated.

  1. Portable sample preparation and analysis system for micron and sub-micron particle characterization using light scattering and absorption spectroscopy

    Science.gov (United States)

    Stark, Peter C.; Zurek, Eduardo; Wheat, Jeffrey V.; Dunbar, John M.; Olivares, Jose A.; Garcia-Rubio, Luis H.; Ward, Michael D.

    2011-07-26

    There is provided a method and device for remote sampling, preparation and optical interrogation of a sample using light scattering and light absorption methods. The portable device is a filtration-based device that removes interfering background particle material from the sample matrix by segregating or filtering the chosen analyte from the sample solution or matrix while allowing the interfering background particles to be pumped out of the device. The segregated analyte is then suspended in a diluent for analysis. The device is capable of calculating an initial concentration of the analyte, as well as diluting the analyte such that reliable optical measurements can be made. Suitable analytes include cells, microorganisms, bioparticles, pathogens and diseases. Sample matrixes include biological fluids such as blood and urine, as well as environmental samples including waste water.

  2. Influence of biomass burning on mixing state of sub-micron aerosol particles in the North China Plain

    Science.gov (United States)

    Kecorius, Simonas; Ma, Nan; Teich, Monique; van Pinxteren, Dominik; Zhang, Shenglan; Gröβ, Johannes; Spindler, Gerald; Müller, Konrad; Iinuma, Yoshiteru; Hu, Min; Herrmann, Hartmut; Wiedensohler, Alfred

    2017-09-01

    Particulate emissions from crop residue burning decrease the air quality as well as influence aerosol radiative properties on a regional scale. The North China Plain (NCP) is known for the large scale biomass burning (BB) of field residues, which often results in heavy haze pollution episodes across the region. We have been able to capture a unique BB episode during the international CAREBeijing-NCP intensive field campaign in Wangdu in the NCP (38.6°N, 115.2°E) from June to July 2014. It was found that aerosol particles originating from this BB event showed a significantly different mixing state compared with clean and non-BB pollution episodes. BB originated particles showed a narrower probability density function (PDF) of shrink factor (SF). And the maximum was found at shrink factor of 0.6, which is higher than in other episodes. The non-volatile particle number fraction during the BB episode decreased to 3% and was the lowest measured value compared to all other predefined episodes. To evaluate the influence of particle mixing state on aerosol single scattering albedo (SSA), SSA at different RHs was simulated using the measured aerosol physical-chemical properties. The differences between the calculated SSA for biomass burning, clean and pollution episodes are significant, meaning that the variation of SSA in different pollution conditions needs to be considered in the evaluation of aerosol direct radiative effects in the NCP. And the calculated SSA was found to be quite sensitive on the mixing state of BC, especially at low-RH condition. The simulated SSA was also compared with the measured values. For all the three predefined episodes, the measured SSA are very close to the calculated ones with assumed mixing states of homogeneously internal and core-shell internal mixing, indicating that both of the conception models are appropriate for the calculation of ambient SSA in the NCP.

  3. Seasonal variations of ultra-fine and submicron aerosols in Taipei, Taiwan: implications for particle formation processes in a subtropical urban area

    Science.gov (United States)

    Cheung, H. C.; Chou, C. C.-K.; Chen, M.-J.; Huang, W.-R.; Huang, S.-H.; Tsai, C.-Y.; Lee, C. S. L.

    2016-02-01

    The aim of this study is to investigate the seasonal variations in the physicochemical properties of atmospheric ultra-fine particles (UFPs, d ≤ 100 nm) and submicron particles (PM1, d ≤ 1 µm) in an east Asian urban area, which are hypothesized to be affected by the interchange of summer and winter monsoons. An observation experiment was conducted at TARO (Taipei Aerosol and Radiation Observatory), an urban aerosol station in Taipei, Taiwan, from October 2012 to August 2013. The measurements included the mass concentration and chemical composition of UFPs and PM1, as well as the particle number concentration (PNC) and the particle number size distribution (PSD) with size range of 4-736 nm. The results indicated that the mass concentration of PM1 was elevated during cold seasons with a peak level of 18.5 µg m-3 in spring, whereas the highest concentration of UFPs was measured in summertime with a mean of 1.64 µg m-3. Moreover, chemical analysis revealed that the UFPs and PM1 were characterized by distinct composition; UFPs were composed mostly of organics, whereas ammonium and sulfate were the major constituents of PM1. The seasonal median of total PNCs ranged from 13.9 × 103 cm-3 in autumn to 19.4 × 103 cm-3 in spring. Median concentrations for respective size distribution modes peaked in different seasons. The nucleation-mode PNC (N4 - 25) peaked at 11.6 × 103 cm-3 in winter, whereas the Aitken-mode (N25 - 100) and accumulation-mode (N100 - 736) PNC exhibited summer maxima at 6.0 × 103 and 3.1 × 103 cm-3, respectively. The change in PSD during summertime was attributed to the enhancement in the photochemical production of condensable organic matter that, in turn, contributed to the growth of aerosol particles in the atmosphere. In addition, clear photochemical production of particles was observed, mostly in the summer season, which was characterized by average particle growth and formation rates of 4.0 ± 1.1 nm h-1 and 1.4 ± 0.8 cm-3 s-1

  4. Observations of residual submicron fine aerosol particles related to cloud and fog processing during a major pollution event in Beijing

    Science.gov (United States)

    Li, Zhengqiang; Eck, Tom; Zhang, Ying; Zhang, Yuhuan; Li, Donghui; Li, Li; Xu, Hua; Hou, Weizhen; Lv, Yang; Goloub, Philippe; Gu, Xingfa

    2014-04-01

    Residual aerosols, the particles left behind after droplet evaporation, are important tracers for aerosols processed by cloud and/or fog. Based on ground-based CIMEL sun-sky radiometer measurements during an extreme winter pollution event in Beijing, we present observations of the decrease of residual aerosol with dissipation of cloud and an unusual case of residual aerosol increase after partial dissipation of fog. This unusual increase might be an important mechanism for the haze growth in polluted regions. The aerosol single scattering albedo is found to increase with the increase of residual aerosol. We also find that residual aerosol dominated cases with significant water content gain can occur in a short time (e.g. one hour) with the increase of aerosol volume size and decrease of particle number. A lognormal residual aerosol size distribution model is proposed based on sun-sky radiometer measurements with center peak radius at 0.44 micron and geometric standard deviation of about 1.49.

  5. Charged particles interacting with a mixed supported lipid bilayer as a biomimetic pulmonary surfactant.

    Science.gov (United States)

    Munteanu, B; Harb, F; Rieu, J P; Berthier, Y; Tinland, B; Trunfio-Sfarghiu, A-M

    2014-08-01

    This study shows the interactions of charged particles with mixed supported lipid bilayers (SLB) as biomimetic pulmonary surfactants. We tested two types of charged particles: positively charged and negatively charged particles. Two parameters were measured: adsorption density of particles on the SLB and the diffusion coefficient of lipids by FRAPP techniques as a measure of interaction strength between particles and lipids. We found that positively charged particles do not adsorb on the bilayer, probably due to the electrostatic repulsion between positively charged parts of the lipid head and the positive groups on the particle surface, therefore no variation in diffusion coefficient of lipid molecules was observed. On the contrary, the negatively charged particles, driven by electrostatic interactions are adsorbed onto the supported bilayer. The adsorption of negatively charged particles increases with the zeta-potential of the particle. Consecutively, the diffusion coefficient of lipids is reduced probably due to binding onto the lipid heads which slows down their Brownian motion. The results are directly relevant for understanding the interactions of particulate matter with pulmonary structures which could lead to pulmonary surfactant inhibition or deficiency causing severe respiratory distress or pathologies.

  6. Accumulation of lipids and oxidatively damaged DNA in hepatocytes exposed to particles

    DEFF Research Database (Denmark)

    Vesterdal, Lise K; Danielsen, Pernille H; Folkmann, Janne K

    2014-01-01

    and subsequently incubated for another 18h to manifest lipid accumulation. In an animal model of metabolic syndrome we investigated the association between intake of carbon black (CB, 14nm) particles and hepatic lipid accumulation, inflammation and gene expression of Srebp-1, Fasn and Scd-1 involved in lipid...... single-walled carbon nanotubes. All four types of particles also generated oxidatively damaged DNA, assessed as formamidopyrimidine DNA glycosylase (FPG) sensitive sites, in HepG2 cells after 3h exposure. The animal model of metabolic syndrome showed increased lipid load in the liver after one oral......Exposure to particles has been suggested to generate hepatosteatosis by oxidative stress mechanisms. We investigated lipid accumulation in cultured human hepatocytes (HepG2) and rat liver after exposure to four different carbon-based particles. HepG2 cells were exposed to particles for 3h...

  7. Modified lipoprotein-derived lipid particles accumulate in human stenotic aortic valves.

    Science.gov (United States)

    Lehti, Satu; Käkelä, Reijo; Hörkkö, Sohvi; Kummu, Outi; Helske-Suihko, Satu; Kupari, Markku; Werkkala, Kalervo; Kovanen, Petri T; Oörni, Katariina

    2013-01-01

    In aortic stenosis plasma lipoprotein-derived lipids accumulate in aortic valves. Here, we first compared the lipid compositions of stenotic aortic valves and atherosclerotic plaque cores. Both pathological tissues were found to be enriched in cholesteryl linoleate, a marker of extracellularly accumulated lipoproteins. In addition, a large proportion of the phospholipids were found to contain arachidonic acid, the common precursor of a number of proinflammatory lipid mediators. Next, we isolated and characterized extracellular lipid particles from human stenotic and non-stenotic control valves, and compared them to plasma lipoproteins from the same subjects. The extracellular valvular lipid particles were isolated from 15 stenotic and 14 non-stenotic aortic valves. Significantly more apoB-100-containing lipid particles were found in the stenotic than in the non-stenotic valves. The majority of the lipid particles isolated from the non-stenotic valves had sizes (23±6.2 nm in diameter) similar to those of plasma low density lipoprotein (LDL) (22±1.5 nm), while the lipid particles from stenotic valves were not of uniform size, their sizes ranging from 18 to more than 500 nm. The lipid particles showed signs of oxidative modifications, and when compared to isolated plasma LDL particles, the lipid particles isolated from the stenotic valves had a higher sphingomyelin/phosphatidylcholine -ratio, and also higher contents of lysophosphatidylcholine and unesterified cholesterol. The findings of the present study reveal, for the first time, that in stenotic human aortic valves, infiltrated plasma lipoproteins have undergone oxidative and lipolytic modifications, and become fused and aggregated. The generated large lipid particles may contribute to the pathogenesis of human aortic stenosis.

  8. Highly time-resolved chemical characterization of atmospheric submicron particles during 2008 Beijing Olympic Games using an Aerodyne High-Resolution Aerosol Mass Spectrometer

    Directory of Open Access Journals (Sweden)

    X.-F. Huang

    2010-09-01

    Full Text Available As part of Campaigns of Air Quality Research in Beijing and Surrounding Region-2008 (CAREBeijing-2008, an Aerodyne High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS was deployed in urban Beijing to characterize submicron aerosol particles during the time of 2008 Beijing Olympic Games and Paralympic Games (24 July to 20 September 2008. The campaign mean PM1 mass concentration was 63.1 ± 39.8 μg m−3; the mean composition consisted of organics (37.9%, sulfate (26.7%, ammonium (15.9%, nitrate (15.8%, black carbon (3.1%, and chloride (0.87%. The average size distributions of the species (except BC were all dominated by an accumulation mode peaking at about 600 nm in vacuum aerodynamic diameter, and organics was characterized by an additional smaller mode extending below 100 nm. Positive Matrix Factorization (PMF analysis of the high resolution organic mass spectral dataset differentiated the organic aerosol into four components, i.e., hydrocarbon-like (HOA, cooking-related (COA, and two oxygenated organic aerosols (OOA-1 and OOA-2, which on average accounted for 18.1, 24.4, 33.7 and 23.7% of the total organic mass, respectively. The HOA was identified to be closely associated with primary combustion sources, while the COA mass spectrum and diurnal pattern showed similar characteristics to that measured for cooking emissions. The OOA components correspond to aged secondary organic aerosol. Although the two OOA components have similar elemental (O/C, H/C compositions, they display differences in mass spectra and time series which appear to correlate with the different source regions sampled during the campaign. Back trajectory clustering analysis indicated that the southerly air flows were associated with the highest PM1 pollution during the campaign. Aerosol particles in southern airmasses were especially rich in inorganic and oxidized organic species. Aerosol particles in northern airmasses

  9. Highly time-resolved chemical characterization of atmospheric submicron particles during 2008 Beijing Olympic Games using an Aerodyne High-Resolution Aerosol Mass Spectrometer

    Directory of Open Access Journals (Sweden)

    X.-F. Huang

    2010-05-01

    Full Text Available As part of Campaigns of Air Quality Research in Beijing and Surrounding Region–2008 (CAREBeijing-2008, an Aerodyne High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS was deployed in urban Beijing to characterize submicron aerosol particles during the time of 2008 Beijing Olympic Games and Paralytic Games (24 July to 20 September 2008. The campaign mean PM1 mass concentration was 63.1±39.8 μg m−3; the mean composition consisted of organics (37.9%, sulfate (26.7%, ammonium (15.9%, nitrate (15.8%, black carbon (3.1%, and chloride (0.87%. The average size distributions of the species (except BC were all dominated by an accumulation mode peaking at about 600 nm in vacuum aerodynamic diameter, and organics was characterized by an additional smaller mode extending below 100 nm. Positive Matrix Factorization (PMF analysis of the high resolution organic mass spectral dataset differentiated the organic aerosol into four components, i.e., hydrocarbon-like (HOA, cooking-related (COA, and two oxygenated organic aerosols (OOA-1 and OOA-2, which on average accounted for 18.1, 24.4, 33.7 and 23.7% of the total organic mass, respectively. The HOA was identified to be closely associated with primary combustion sources, while the COA mass spectrum showed high similarity to that measured from cooking aerosol emissions. The OOA components correspond to aged secondary organic aerosol. Although the two OOA components have similar elemental (O/C, H/C compositions, they display differences in mass spectra and time series which appear to correlate with the different source regions sampled during the campaign. Back trajectory clustering analysis indicated that the southerly air flows were associated with the highest PM1 pollution during the campaign. This result is similar to observations made in the summer of 2006, although the average PM1 concentration level for the southerly air flows is 31% lower than

  10. Repair of Cranial Bone Defects Using rhBMP2 and Submicron Particle of Biphasic Calcium Phosphate Ceramics with Through-Hole

    Directory of Open Access Journals (Sweden)

    Byung-Chul Jeong

    2015-01-01

    Full Text Available Recently a submicron particle of biphasic calcium phosphate ceramic (BCP with through-hole (donut-shaped BCP (d-BCP was developed for improving the osteoconductivity. This study was performed to examine the usefulness of d-BCP for the delivery of osteoinductive rhBMP2 and the effectiveness on cranial bone regeneration. The d-BCP was soaked in rhBMP2 solution and then freeze-dried. Scanning electron microscope (SEM, energy dispersive spectroscopy (EDS, and Raman spectroscopy analyses confirmed that rhBMP2 was well delivered onto the d-BCP surface and the through-hole. The bioactivity of the rhBMP2/d-BCP composite was validated in MC3T3-E1 cells as an in vitro model and in critical-sized cranial defects in C57BL/6 mice. When freeze-dried d-BCPs with rhBMP2 were placed in transwell inserts and suspended above MC3T3-E1, alkaline phosphatase activity and osteoblast-specific gene expression were increased compared to non-rhBMP2-containing d-BCPs. For evaluating in vivo effectiveness, freeze-dried d-BCPs with or without rhBMP2 were implanted into critical-sized cranial defects. Microcomputed tomography and histologic analysis showed that rhBMP2-containing d-BCPs significantly enhanced cranial bone regeneration compared to non-rhBMP2-containing control. These results suggest that a combination of d-BCP and rhBMP2 can accelerate bone regeneration, and this could be used to develop therapeutic strategies in hard tissue healing.

  11. Repair of Cranial Bone Defects Using rhBMP2 and Submicron Particle of Biphasic Calcium Phosphate Ceramics with Through-Hole.

    Science.gov (United States)

    Jeong, Byung-Chul; Choi, Hyuck; Hur, Sung-Woong; Kim, Jung-Woo; Oh, Sin-Hye; Kim, Hyun-Seung; Song, Soo-Chang; Lee, Keun-Bae; Park, Kwang-Bum; Koh, Jeong-Tae

    2015-01-01

    Recently a submicron particle of biphasic calcium phosphate ceramic (BCP) with through-hole (donut-shaped BCP (d-BCP)) was developed for improving the osteoconductivity. This study was performed to examine the usefulness of d-BCP for the delivery of osteoinductive rhBMP2 and the effectiveness on cranial bone regeneration. The d-BCP was soaked in rhBMP2 solution and then freeze-dried. Scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), and Raman spectroscopy analyses confirmed that rhBMP2 was well delivered onto the d-BCP surface and the through-hole. The bioactivity of the rhBMP2/d-BCP composite was validated in MC3T3-E1 cells as an in vitro model and in critical-sized cranial defects in C57BL/6 mice. When freeze-dried d-BCPs with rhBMP2 were placed in transwell inserts and suspended above MC3T3-E1, alkaline phosphatase activity and osteoblast-specific gene expression were increased compared to non-rhBMP2-containing d-BCPs. For evaluating in vivo effectiveness, freeze-dried d-BCPs with or without rhBMP2 were implanted into critical-sized cranial defects. Microcomputed tomography and histologic analysis showed that rhBMP2-containing d-BCPs significantly enhanced cranial bone regeneration compared to non-rhBMP2-containing control. These results suggest that a combination of d-BCP and rhBMP2 can accelerate bone regeneration, and this could be used to develop therapeutic strategies in hard tissue healing.

  12. Separation of submicron bioparticles by dielectrophoresis.

    OpenAIRE

    Morgan, H.; Hughes, M P; Green, N G

    1999-01-01

    Submicron particles such as latex spheres and viruses can be manipulated and characterized using dielectrophoresis. By the use of appropriate microelectrode arrays, particles can be trapped or moved between regions of high or low electric fields. The magnitude and direction of the dielectrophoretic force on the particle depends on its dielectric properties, so that a heterogeneous mixture of particles can be separated to produce a more homogeneous population. In this paper the controlled sepa...

  13. The Impact of Variables on Particle Size of Solid Lipid Nanoparticles and Nanostructured Lipid Carriers; A Comparative Literature Review

    Science.gov (United States)

    Azhar Shekoufeh Bahari, Leila; Hamishehkar, Hamed

    2016-01-01

    During the past decade, pharmaceutical science has seen rapid growth in interest for nanoscale materials. Solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) are popular research topics recently introduced as nano-scale drug carriers; they have shown numerous merits in drug delivery. Size is the most important index in a nanocarrier affecting its drug delivery efficiency. The influence of preparation conditions and type of lipidic components on the size of SLN and NLC in comparable states seems to be interesting for researchers who investigate these types of carriers. This review highlights the results of SLN and NLC particle size and size distribution comparisons. PMID:27478775

  14. Electrospray crystallization for high-quality submicron-sized crystals

    NARCIS (Netherlands)

    Radacsi, N.; Stankiewicz, A.I.; Creyghton, Y.L.M.; Heijden, A.E.D.M. van der; Horst, J.H. ter

    2011-01-01

    Nano- and submicron-sized crystals are too small to contain inclusions and are, therefore, expected to have a higher internal quality compared to conventionally sized particles (several tens to hundreds of microns). Using electrospray crystallization, nano- and submicron-sized crystals can be easily

  15. Non-lamellar lipid assembly at interfaces: controlling layer structure by responsive nanogel particles.

    Science.gov (United States)

    Dabkowska, Aleksandra P; Valldeperas, Maria; Hirst, Christopher; Montis, Costanza; Pálsson, Gunnar K; Wang, Meina; Nöjd, Sofi; Gentile, Luigi; Barauskas, Justas; Steinke, Nina-Juliane; Schroeder-Turk, Gerd E; George, Sebastian; Skoda, Maximilian W A; Nylander, Tommy

    2017-08-06

    Biological membranes do not only occur as planar bilayer structures, but depending on the lipid composition, can also curve into intriguing three-dimensional structures. In order to fully understand the biological implications as well as to reveal the full potential for applications, e.g. for drug delivery and other biomedical devices, of such structures, well-defined model systems are required. Here, we discuss the formation of lipid non-lamellar liquid crystalline (LC) surface layers spin-coated from the constituting lipids followed by hydration of the lipid layer. We demonstrate that hybrid lipid polymer films can be formed with different properties compared with the neat lipid LC layers. The nanostructure and morphologies of the lipid films formed reflect those in the bulk. Most notably, mixed lipid layers, which are composed of glycerol monooleate and diglycerol monooleate with poly(N-isopropylacrylamide) nanogels, can form films of reverse cubic phases that are capable of responding to temperature stimulus. Owing to the presence of the nanogel particles, changing the temperature not only regulates the hydration of the cubic phase lipid films, but also the lateral organization of the lipid domains within the lipid self-assembled film. This opens up the possibility for new nanostructured materials based on lipid-polymer responsive layers.

  16. Supercritical fluid precipitation of ketoprofen in novel structured lipid carriers for enhanced mucosal delivery--a comparison with solid lipid particles.

    Science.gov (United States)

    Gonçalves, V S S; Matias, A A; Rodríguez-Rojo, S; Nogueira, I D; Duarte, C M M

    2015-11-10

    Structured lipid carriers based on mixture of solid lipids with liquid lipids are the second generation of solid lipid particles, offering the advantage of improved drug loading capacity and higher storage stability. In this study, structured lipid carriers were successfully prepared for the first time by precipitation from gas saturated solutions. Glyceryl monooleate (GMO), a liquid glycerolipid, was selected in this work to be incorporated into three solid glycerolipids with hydrophilic-lipophilic balance (HLB) ranging from 1 to 13, namely Gelucire 43/01™, Geleol™ and Gelucire 50/13™. In general, microparticles with a irregular porous morphology and a wide particle size distribution were obtained. The HLB of the individual glycerolipids might be a relevant parameter to take into account during the processing of solid:liquid lipid blends. As expected, the addition of a liquid lipid into a solid lipid matrix led to increased stability of the lipid carriers, with no significant modifications in their melting enthalpy after 6 months of storage. Additionally, Gelucire 43/01™:GMO particles were produced with different mass ratios and loaded with ketoprofen. The drug loading capacity of the structured lipid carriers increased as the GMO content in the particles increased, achieving a maximum encapsulation efficiency of 97% for the 3:1 mass ratio. Moreover, structured lipid carriers presented an immediate release of ketoprofen from its matrix with higher permeation through a mucous-membrane model, while solid lipid particles present a controlled release of the drug with less permeation capacity.

  17. Changes in lipids and lipoprotein particle concentrations after interruption of antiretroviral therapy

    DEFF Research Database (Denmark)

    Lampe, Fiona C; Duprez, Daniel A; Kuller, Lewis H

    2010-01-01

    The effect of interruption of antiretroviral therapy (ART) on lipoprotein particle subclasses has not been studied. We examined short-term changes in lipids and lipoprotein particles among 332 HIV-infected individuals randomized to interrupt or continue ART in the "Strategies for Management...... of Antiretroviral Therapy" trial....

  18. Food-grade Pickering emulsions stabilised with solid lipid particles.

    Science.gov (United States)

    Pawlik, Aleksandra; Kurukji, Daniel; Norton, Ian; Spyropoulos, Fotis

    2016-06-15

    Aqueous dispersions of tripalmitin particles (with a minimum size of 130 nm) were produced, via a hot sonication method, with and without the addition of food-grade emulsifiers. Depending on their relative size and chemistry, the emulsifiers altered the properties of the fat particles (e.g. crystal form, dispersion state and surface properties) by two proposed mechanisms. Firstly, emulsifiers modify the rate and/or extent of polymorphic transitions, resulting in the formation of fat crystals with a range of polarities. Secondly, the adsorption of emulsifiers at the particle interface modifies crystal surface properties. Such emulsifier-modified fat particles were then used to stabilise emulsions. As the behaviour of these particles was predisposed by the kind of emulsifier employed for their manufacture, the resulting particles showed different preferences to which of the emulsion phases (oil or water) became the continuous one. The polarity of the fat particles decreased as follows: Whey Protein Isolate > Soy Lecithin > Soy Lecithin + Tween 20 > Tween 20 > Polyglycerol Polyricinoleate > no emulsifier. Consequently, particles stabilised with WPI formed oil-in-water emulsions (O/W); particles stabilised solely with lecithin produced a highly unstable W/O emulsion; and particles stabilised with a mixture of lecithin and Tween 20 gave a stable W/O emulsion with drop size up to 30 μm. Coalescence stable, oil-continuous emulsions (W/O) with drop sizes between 5 and 15 μm were produced when the tripalmitin particles were stabilised with solely with Tween 20, solely with polyglycerol polyricinoleate, or with no emulsifier at all. It is proposed that the stability of the latter three emulsions was additionally enhanced by sintering of fat particles at the oil-water interface, providing a mechanical barrier against coalescence.

  19. Accumulation of lipids and oxidatively damaged DNA in hepatocytes exposed to particles

    Energy Technology Data Exchange (ETDEWEB)

    Vesterdal, Lise K.; Danielsen, Pernille H.; Folkmann, Janne K.; Jespersen, Line F.; Aguilar-Pelaez, Karin; Roursgaard, Martin; Loft, Steffen; Møller, Peter, E-mail: pemo@sund.ku.dk

    2014-01-15

    Exposure to particles has been suggested to generate hepatosteatosis by oxidative stress mechanisms. We investigated lipid accumulation in cultured human hepatocytes (HepG2) and rat liver after exposure to four different carbon-based particles. HepG2 cells were exposed to particles for 3 h and subsequently incubated for another 18 h to manifest lipid accumulation. In an animal model of metabolic syndrome we investigated the association between intake of carbon black (CB, 14 nm) particles and hepatic lipid accumulation, inflammation and gene expression of Srebp-1, Fasn and Scd-1 involved in lipid synthesis. There was a concentration-dependent increase in intracellular lipid content after exposure to CB in HepG2 cells, which was only observed after co-exposure to oleic/palmitic acid. Similar results were observed in HepG2 cells after exposure to diesel exhaust particles, fullerenes C{sub 60} or pristine single-walled carbon nanotubes. All four types of particles also generated oxidatively damaged DNA, assessed as formamidopyrimidine DNA glycosylase (FPG) sensitive sites, in HepG2 cells after 3 h exposure. The animal model of metabolic syndrome showed increased lipid load in the liver after one oral exposure to 6.4 mg/kg of CB in lean Zucker rats. This was not associated with increased iNOS staining in the liver, indicating that the oral CB exposure was associated with hepatic steatosis rather than steatohepatitis. The lipid accumulation did not seem to be related to increased lipogenesis because there were unaltered gene expression levels in both the HepG2 cells and rat livers. Collectively, exposure to particles is associated with oxidative stress and steatosis in hepatocytes. - Highlights: • Oral exposure to nanosized carbon black was associated with hepatosteatosis in rats. • In vitro studies included carbon black, C{sub 60}, diesel exhaust particles and SWCNTs. • Exposure to particles and free fatty acids increased lipid load in HepG2 cells. • Unaltered

  20. Solid lipid particles for oral delivery of peptide and protein drugs I - Elucidating the release mechanism of lysozyme during lipolysis

    DEFF Research Database (Denmark)

    Christophersen, Philip Carsten B; Zhang, L.; Yang, M

    2013-01-01

    The mechanism of protein release from solid lipid particles was investigated by a new lipolysis model in a biorelevant medium containing both bile salts and phospholipids. Lysozyme, a model protein, was formulated into solid lipid particles using four different types of lipids, two triglycerides...... with different chain-length of fatty acyl groups i.e. trimyristin (TG14) and tristearin (TG18), and two lipid blends dominated by diglycerides and monoglycerides, respectively. The release of lysozyme from the solid lipid particles and the lipid hydrolysis process were assessed in the lipolysis model, while...... the drug release mechanism from solid lipid particles and can potentially be used in rational selection of lipid excipients for oral delivery of peptide/protein drugs....

  1. Porous Silica-Supported Solid Lipid Particles for Enhanced Solubilization of Poorly Soluble Drugs.

    Science.gov (United States)

    Yasmin, Rokhsana; Rao, Shasha; Bremmell, Kristen E; Prestidge, Clive A

    2016-07-01

    Low dissolution of drugs in the intestinal fluid can limit their effectiveness in oral therapies. Here, a novel porous silica-supported solid lipid system was developed to optimize the oral delivery of drugs with limited aqueous solubility. Using lovastatin (LOV) as the model poorly water-soluble drug, two porous silica-supported solid lipid systems (SSL-A and SSL-S) were fabricated from solid lipid (glyceryl monostearate, GMS) and nanoporous silica particles Aerosil 380 (silica-A) and Syloid 244FP (silica-S) via immersion/solvent evaporation. SSL particles demonstrated significantly higher rate and extent of lipolysis in comparison with the pure solid lipid, depending on the lipid loading levels and the morphology. The highest lipid digestion was observed when silica-S was loaded with 34% (w/w) solid lipid, and differential scanning calorimeter (DSC) analysis confirmed the encapsulation of up to 2% (w/w) non-crystalline LOV in this optimal SSL-S formulation. Drug dissolution under non-digesting intestinal conditions revealed a three- to sixfold increase in dissolution efficiencies when compared to the unformulated drug and a LOV-lipid suspension. Furthermore, the SSL-S provided superior drug solubilization under simulated intestinal digesting condition in comparison with the drug-lipid suspension and drug-loaded silica. Therefore, solid lipid and nanoporous silica provides a synergistic effect on optimizing the solubilization of poorly water-soluble compound and the solid lipid-based porous carrier system provides a promising delivery approach to overcome the oral delivery challenges of poorly water-soluble drugs.

  2. Lipid particle size effect on water vapor permeability and mechanical properties of whey protein/beeswax emulsion films.

    Science.gov (United States)

    Pérez-Gago, M B; Krochta, J M

    2001-02-01

    Lipid particle size effects on water vapor permeability (WVP) and mechanical properties of whey protein isolate (WPI)/beeswax (BW) emulsion films were investigated. Emulsion films containing 20 and 60% BW (dry basis) and mean lipid particle sizes ranging from 0.5 to 2.0 microm were prepared. BW particle size effects on WVP and mechanical properties were observed only in films containing 60% BW. WVP of these films decreased as lipid particle size decreased. As drying temperature increased, film WVPs decreased significantly. Meanwhile, tensile strength and elongation increased as BW particle size decreased. However, for 20% BW emulsion films, properties were not affected by lipid particle size. Results suggest that increased protein-lipid interactions at the BW particle interfaces, as particle size decreased and resulting interfacial area increased, result in stronger films with lower WVPs. Observing this effect depends on a large lipid content within the protein matrix. At low lipid content, the effect of interactions at the protein-lipid interfaces is not observed, due to the presence of large protein-matrix regions of the film without lipid, which are not influenced by protein-lipid interactions.

  3. Incorporation of ovalbumin into ISCOMs and related colloidal particles prepared by the lipid film hydration method.

    Science.gov (United States)

    Demana, Patrick H; Davies, Nigel M; Berger, Bianca; Rades, Thomas

    2004-07-08

    The aim of this study was to investigate the incorporation of a model antigen, fluorescently labelled ovalbumin (FITC-OVA), into various colloidal particles including immune stimulating complexes (ISCOMs), liposomes, ring and worm-like micelles, lamellae and lipidic/layered structures that are formed from various combinations of the triterpene saponin Quil A, cholesterol and phosphatidylethanolamine (PE) following hydration of PE/cholesterol lipid films with aqueous solutions of Quil A. Colloidal dispersions of these three components were also prepared by the dialysis method for comparison. FITC-OVA was conjugated with palmitic acid (P) and PE to produce P-FITC-OVA and PE-FITC-OVA, respectively. Both P-FITC-OVA and PE-FITC-OVA could be incorporated in all colloidal structures whereas FITC-OVA was incorporated only into liposomes. The incorporation of PE-FITC-OVA into all colloidal structures was significantly higher than P-FITC-OVA (P < 0.05). The degree of incorporation of protein was in the order: ring and worm-like micelles < liposomes and lipidic/layered structures < ISCOMs and lamellae. The incorporation of protein into the various particles prepared by the lipid film hydration method was similar to those for colloidal particles prepared by the dialysis method (provided both methods lead to the formation of the same colloidal structures). In the case of different colloidal structures arising due to the preparation method, differences in encapsulation efficiency were found (P < 0.05) for formulations with the same polar lipid composition. This study demonstrates that the various colloidal particles formed as a result of hydrating PE/cholesterol lipid films with different amounts of Quil A are capable of incorporating antigen, provided it is amphipathic. Some of these colloidal particles may be used as effective vaccine delivery systems.

  4. Control of lignin solubility and particle formation modulates its antioxidant efficiency in lipid medium

    DEFF Research Database (Denmark)

    Barsberg, Søren Talbro; Thygesen, Lisbeth Garbrecht; Sanadi, Anand Ramesh

    2014-01-01

    Lignin is an abundant plant polymer usually regarded as waste material. In the present work, antioxidant properties of lignin preparations with differing lipid solubility were studied using biodiesel as a convenient lipid test substrate. In place of formerly used assays, we used attenuated total...... reflectance (ATR) FT-IR spectroscopy to follow in situ biodiesel autoxidation on a heated ATR crystal as a function of time. The study demonstrates that a complex balance between intrinsic (chemical) efficiency, solubility, and particle formation controls the antioxidant efficiency of differently prepared...... lignin fractions. It was found that solubility and particle formation of lignin preparations strongly modulate its antioxidant efficiency and that these properties might depend on the presence of lipid components within the original lignin source....

  5. Automobile diesel exhaust particles induce lipid droplet formation in macrophages in vitro

    DEFF Research Database (Denmark)

    Cao, Yi; Jantzen, Kim; Gouveia, Ana Cecilia Damiao

    2015-01-01

    Exposure to diesel exhaust particles (DEP) has been associated with adverse cardiopulmonary health effects, which may be related to dysregulation of lipid metabolism and formation of macrophage foam cells. In this study, THP-1 derived macrophages were exposed to an automobile generated DEP (A...

  6. Automobile diesel exhaust particles induce lipid droplet formation in macrophages in vitro.

    Science.gov (United States)

    Cao, Yi; Jantzen, Kim; Gouveia, Ana Cecilia Damiao; Skovmand, Astrid; Roursgaard, Martin; Loft, Steffen; Møller, Peter

    2015-07-01

    Exposure to diesel exhaust particles (DEP) has been associated with adverse cardiopulmonary health effects, which may be related to dysregulation of lipid metabolism and formation of macrophage foam cells. In this study, THP-1 derived macrophages were exposed to an automobile generated DEP (A-DEP) for 24h to study lipid droplet formation and possible mechanisms. The results show that A-DEP did not induce cytotoxicity. The production of reactive oxygen species was only significantly increased after exposure for 3h, but not 24h. Intracellular level of reduced glutathione was increased after 24h exposure. These results combined indicate an adaptive response to oxidative stress. Exposure to A-DEP was associated with significantly increased formation of lipid droplets, as well as changes in lysosomal function, assessed as reduced LysoTracker staining. In conclusion, these results indicated that exposure to A-DEP may induce formation of lipid droplets in macrophages in vitro possibly via lysosomal dysfunction.

  7. [In vitro experimental study of rat cardiomyocyte injury with targeting of perfluorocarbon lipid particles].

    Science.gov (United States)

    He, Baiyong; Li, Zhaohuan; Tang, Hong; Li, Guohua; Chen, Song; Wang, Lian; Song, Haibo; Fang, Hua; Zeng, Jun

    2011-12-01

    The present study was to investigate in vitro the rat cardiomyocyte injury with targeting of home-made perfluorocarbon lipid particles with avidin-biotin interaction. Neonatal rat cardiomyocytes were cultured in vitro and divided into two groups: TNF-alpha activated group and non-activated group. Those in the TNF-alpha activated group were exposed to 200 ng/ml TNF-alpha solution for 6 hours and then cardiomyocytes in both groups were pretargeted with biotinylated ICAM-1 monoclonal antibodies, and were exposed to streptavidin, and then to homemade green fluorescently-labeled biotinylated perfluorocarbon lipid particles. Cardiomyocytes nucleus stained with Hoechst. The results were detected with fluorescence microscope. As a result, in TNF-alpha activated group, around blue fluorescent cardiomyocytes nucleus, a great amount of green fluorescent particles were found, while there were few green fluorescent particles in non-TNF activated group. It has been shown that ICAM-1 is expressed in the surface of cardiomyocytes when they are stimulated by TNF-alpha. Perfluorocarbon lipid particles associated with ICAM-1 monoclonal antibodies can be targeted to injured cardiomyocytes by avidin-biotin interaction.

  8. Sub-micron ZnO:N particles fabricated by low voltage electrical discharge lithography on Zn{sub 3}N{sub 2} sputtered films

    Energy Technology Data Exchange (ETDEWEB)

    Núñez, C. García, E-mail: carlos.garcia@uam.es [Dpt. de Física Aplicada, Laboratorio de Microelectrónica, Universidad Autónoma de Madrid, 28020 Madrid (Spain); Jiménez-Trillo, J. [Dpt. Ingeniería de Circuitos y Sistemas, EUIT Telecomunicación, Universidad Politécnica de Madrid, Campus Sur, 28031 Madrid (Spain); Vélez, M. García [Dpt. Tecnología Electrónica, Escuela Superior de C.C. Experimentales y Tecnología, Universidad Rey Juan Carlos, 28933 Madrid (Spain); Piqueras, J.; Pau, J.L. [Dpt. de Física Aplicada, Laboratorio de Microelectrónica, Universidad Autónoma de Madrid, 28020 Madrid (Spain); Coya, C.; Álvarez, A.L. [Dpt. Tecnología Electrónica, Escuela Superior de C.C. Experimentales y Tecnología, Universidad Rey Juan Carlos, 28933 Madrid (Spain)

    2013-11-15

    This work analyzes the morphological, compositional and electrical modification of zinc nitride (Zn{sub 3}N{sub 2}) films through arc discharges produced by biasing a metal tip at a micrometric distance of the surface. Polycrystalline nitride layers are prepared by radio-frequency magnetron sputtering from a pure Zn target on glass substrates using N{sub 2} as working gas. Film properties after arc discharges are investigated by using scanning electron microscopy (SEM), ion beam analysis (IBA) techniques and four-probe resistivity measurements. Electrical discharge lithography performed at low bias voltages reveals as an effective mechanism to reduce resistivity by electrical breakdown of the thin oxide layer formed on top of the nitride. At higher voltages, electrical discharges along the scan increase nitride resistivity due to the severe modification of the structural properties. Additionally, compositional analysis reveals that nitrogen leaves the structure being replaced by ambient oxygen. This characteristic behavior leads to the formation of facetted submicron ZnO crystals whose size depends on the original Zn{sub 3}N{sub 2} grain size and the probe voltage used. The excess of zinc forms self-assembled microstructures along the scan edge.

  9. Influence of post-annealing on the properties of Fe{sub 50}Pt{sub 50} film and submicron size particles

    Energy Technology Data Exchange (ETDEWEB)

    Hanson, Maj E-mail: maj.hanson@fy.chalmers.se; Kazakova, Olga; Svedberg, E.B

    2004-05-01

    The magnetic properties of a 48 nm thick Fe{sub 50}Pt{sub 50} film and submicron size elements made of the film were investigated. The initial film was grown by DC magnetron sputtering and post-annealed during 30 min at 300 deg. C. Arrays of circular dots with diameters d=200, 300 and 550 nm and a reference sample (diameter 1.7 mm) were made of the film by electron lithography and Ar ion milling. After structural analysis by X-ray diffraction (XRD) and characterization by magnetization measurements and magnetic force microscopy, all samples were further annealed during 30 min at 600 deg. C. The XRD scans show that this led to an improvement of the crystalline quality in all samples, to a degree depending on the size of the dots. Both the structural and magnetic measurements imply that after the second heat treatment all samples have the easy magnetocrystalline direction (c-axis) mainly in the plane of the film, while the initial structures were characterized by a random distribution of c-axes.

  10. Bottom-up synthesis of up-converting submicron-sized Er{sup 3+}-doped LiNbO{sub 3} particles

    Energy Technology Data Exchange (ETDEWEB)

    Jardiel, T., E-mail: jardiel@icv.csic.es [Departamento de Electroceramica, Instituto de Ceramica y Vidrio-CSIC, Kelsen 5, 28049 Madrid (Spain); Caballero, A.C. [Departamento de Electroceramica, Instituto de Ceramica y Vidrio-CSIC, Kelsen 5, 28049 Madrid (Spain); Marin-Dobrincic, M.; Cantelar, E.; Cusso, F. [Departamento de Fisica de Materiales, C-04, Facultad de Ciencias, Universidad Autonoma de Madrid, Avda. Francisco Tomas y Valiente 7, 28049 Madrid (Spain)

    2012-08-15

    A new and simple wet chemical synthesis method is proposed to prepare submicron-sized Erbium-doped LiNbO{sub 3} powders. The synthesis procedure comprises the co-precipitation of lithium and erbium ions from common precursors and their subsequent reaction with niobium ethoxide. A systematic characterization by means of X-Ray Diffraction (XRD), X-ray Fluorescence (XRF), Inductively Coupled Plasma (ICP-OES), Atomic Absorption (AAS), Field Emission Scanning Electron Microscopy (FE-SEM), as well as by the examination of the luminescence properties, evidence that with this method a congruent Er{sup 3+}-doped LiNbO{sub 3} single phase material can be obtained without using complex and time-consuming processing steps. The synthesized powders exhibit efficient IR to VIS up-conversion emissions under 974 nm pumping. -- Highlights: Black-Right-Pointing-Pointer A novel chemical route to the preparation of LiNbO{sub 3} powders has been developed. Black-Right-Pointing-Pointer This process avoids complex and time-consuming processing steps. Black-Right-Pointing-Pointer A congruent Er{sup 3+}-doped LiNbO{sub 3} single phase material can be obtained by this way. Black-Right-Pointing-Pointer The luminescence properties are the expected for this composition.

  11. 超声均质微悬浮聚合制备亚微米级聚苯乙烯胶粒%Preparation of submicron polystyrene particles by micro-suspension polymerization with ultrasonic homogenization

    Institute of Scientific and Technical Information of China (English)

    戚栋明; 赵晓丽; 陈智杰; 吴明华

    2014-01-01

    Using styrene as typical monomer, polyvinyl alcohol PVA as dispersant, hexadecane HD as co-stabilizer, NaNO2 as water-soluble polymerization inhibitor, a series of submicron polystyrene particles were prepared by micro-suspension polymerization with the help of ultrasonic homogenization. The formation of submicron droplets during homogenization and the variation of particles size and size distribution of disperse phase during polymerization were investigated. It was found that the combination of ultrasonic homogenization and polymer dispersant was conducive to reducing the size of monomer droplet and stabilizing the micro-suspension. The synergistic effect of PVA adsorbed on the surface of droplets, HD dispersed in the droplets phase and NaNO2 dispersed in the water phase facilitated maintenance of disperse phase size during polymerization. Thus the size of colloidal particles could be controlled by varying ultrasonic intensity. Comparing with the conventional micro-suspension polymerization using shear homogenization, the micro-suspension polymerization using ultrasonic homogenization was more suitable to fill the particle size gap between (mini-)emulsion polymerization and suspension polymerization, and more likely to encapsulate the submicron target contents.%以苯乙烯St为代表性单体,以聚乙烯醇PVA为分散剂,以十六烷HD为助稳定剂,以亚硝酸钠NaNO2为水相阻聚剂,通过基于超声均质化的微悬浮聚合制得了一系列亚微米级聚苯乙烯胶粒。对亚微米级单体液滴的均质化产生及后续聚合过程中分散相尺寸的变化进行了考察。发现超声均质化和高分子分散剂的结合有利于制备粒径小、分布窄的稳定微悬浮液滴,而吸附于液滴表面的高分子分散剂、油相内的助稳定剂及水相中的阻聚剂的协同作用能使聚合过程较好地保持分散相原有的粒径大小及分布。因而通过改变超声均质强度,可较容易地在0.5~3.5

  12. Observational study of lipid profile and LDL particle size in patients with metabolic syndrome

    Directory of Open Access Journals (Sweden)

    Martínez-Mernández Pedro

    2011-09-01

    Full Text Available Abstract Background The atherogenic lipoprotein phenotype is characterized by an increase in plasma triglycerides, a decrease in high-density lipoprotein cholesterol (HDLc, and the prevalence of small, dense-low density lipoprotein cholesterol (LDLc particles. The aim of this study was to establish the importance of LDL particle size measurement by gender in a group of patients with Metabolic Syndrome (MS attending at a Cardiovascular Risk Unit in Primary Care and their classification into phenotypes. Subjects and methods One hundred eighty-five patients (93 men and 92 women from several areas in the South of Spain, for a period of one year in a health centre were studied. Laboratory parameters included plasma lipids, lipoproteins, low-density lipoprotein size and several atherogenic rates were determinated. Results We found differences by gender between anthropometric parameters, blood pressure and glucose measures by MS status. Lipid profile was different in our two study groups, and gender differences in these parameters within each group were also remarkable, in HDLc and Apo A-I values. According to LDL particle size, we found males had smaller size than females, and patients with MS had also smaller than those without MS. We observed inverse relationship between LDL particle size and triglycerides in patients with and without MS, and the same relationship between all atherogenic rates in non-MS patients. When we considered our population in two classes of phenotypes, lipid profile was worse in phenotype B. Conclusion In conclusion, we consider worthy the measurement of LDL particle size due to its relationship with lipid profile and cardiovascular risk.

  13. Filter-less submicron hydrodynamic size sorting.

    Science.gov (United States)

    Fouet, M; Mader, M-A; Iraïn, S; Yanha, Z; Naillon, A; Cargou, S; Gué, A-M; Joseph, P

    2016-02-21

    We propose a simple microfluidic device able to separate submicron particles (critical size ∼0.1 μm) from a complex sample with no filter (minimum channel dimension being 5 μm) by hydrodynamic filtration. A model taking into account the actual velocity profile and hydrodynamic resistances enables prediction of the chip sorting properties for any geometry. Two design families are studied to obtain (i) small sizes within minutes (low-aspect ratio, two-level chip) and (ii) micron-sized sorting with a μL flow rate (3D architecture based on lamination). We obtain quantitative agreement of sorting performances both with experiments and with numerical solving, and determine the limits of the approach. We therefore demonstrate a passive, filter-less sub-micron size sorting with a simple, robust, and easy to fabricate design.

  14. Macrophage reactivity to different polymers demonstrates particle size- and material-specific reactivity: PEEK-OPTIMA(®) particles versus UHMWPE particles in the submicron, micron, and 10 micron size ranges.

    Science.gov (United States)

    Hallab, Nadim James; McAllister, Kyron; Brady, Mark; Jarman-Smith, Marcus

    2012-02-01

    Biologic reactivity to orthopedic implant debris is generally the main determinant of long-term clinical performance where released polymeric particles of Ultra-high molecular weight polyethylene (UHMWPE) remain the most prevalent debris generated from metal-on-polymer bearing total joint arthroplasties. Polymeric alternatives to UHMWPE such as polyetherether-ketone (PEEK) may have increased wear resistance but the bioreactivity of PEEK-OPTIMA particles on peri-implant inflammation remains largely uncharacterized. We evaluated human monocyte/macrophage responses (THP-1s and primary human) when challenged by PEEK-OPTIMA, UHMWPE, and X-UHMWPE particles of three particle sizes (0.7 um, 2 um, and 10 um) at a dose of 20 particles-per-cell at 24- and 48-h time points. Macrophage responses were measured using cytotoxicity assays, viability assays, proliferation assays and cytokine analysis (IL-1b, IL-6, IL-8, MCP-1, and TNF-α). In general, there were no significant differences between PEEK-OPTIMA, UHMWPE, and X-UHMWPE particles on macrophage viability or proliferation. However, macrophages demonstrated greater cytotoxicity responses to UHMWPE and X-UHMWPE than to PEEK-OPTIMA at 24 and 48 h, where 0.7 μm-UHMWPE particles produced the highest amount of cytotoxicity. Particles of X-UHMWPE more than PEEK-OPTIMA and UHMWPE induced IL-1β, IL-6, MCP-1, and TNF-α at 24 h, p UHMWPE particles, in that they induced less inflammatory cytokine responses and thus, in part, demonstrates that PEEK-OPTIMA implant debris does not represent an increased inflammatory risk over that of UHMWPE.

  15. Lactosomes: structural and compositional classification of unique nanometer-sized protein lipid particles of human milk

    OpenAIRE

    2010-01-01

    Milk fat globules (MFG) are accepted primarily as triacylglycerol delivery systems. The identification of nanometer-sized lipid-protein particles termed ‘lactosomes’ that do not contain triacylglycerol raises the question of their possible functions. MFGs were isolated by slow centrifugation and lactosomes were isolated by ultracentrifugation at a density equivalent to plasma HDL (d > 1.063 g/ml) from human milk obtained from six volunteers at different lactation stages. Isolated lactosomes w...

  16. Fabrication of a multi-walled carbon nanotube-deposited glass fiber air filter for the enhancement of nano and submicron aerosol particle filtration and additional antibacterial efficacy.

    Science.gov (United States)

    Park, Jae Hong; Yoon, Ki Young; Na, Hyungjoo; Kim, Yang Seon; Hwang, Jungho; Kim, Jongbaeg; Yoon, Young Hun

    2011-09-01

    We grew multi-walled carbon nanotubes (MWCNTs) on a glass fiber air filter using thermal chemical vapor deposition (CVD) after the filter was catalytically activated with a spark discharge. After the CNT deposition, filtration and antibacterial tests were performed with the filters. Potassium chloride (KCl) particles (pressure drop across the filter. When a pristine glass fiber filter that had no CNTs was used, the particle filtration efficiencies at particle sizes under 30 nm and near 500 nm were 48.5% and 46.8%, respectively. However, the efficiencies increased to 64.3% and 60.2%, respectively, when the CNT-deposited filter was used. The reduction in the number of viable cells was determined by counting the colony forming units (CFU) of each test filter after contact with the cells. The pristine glass fiber filter was used as a control, and 83.7% of the E. coli were inactivated on the CNT-deposited filter.

  17. Ionizer assisted air filtration for collection of submicron and ultrafine particles-evaluation of long-term performance and influencing factors.

    Science.gov (United States)

    Shi, Bingbing; Ekberg, Lars

    2015-06-02

    Previous research has demonstrated that unipolar ionization can enhance the filter performance to collect airborne particles, aeroallergens, and airborne microorganisms, without affecting the filter pressure drop. However, there is a lack of research on the long-term system performance as well as the influence of environmental and operational parameters. In this paper, both field and laboratory tests were carried out to evaluate the long-term particle collection efficiency of a synthetic filter of class M6 with and without ionization. The effect of air velocity, temperature, relative humidity, and particle concentration were further investigated in laboratory tests. Results showed that ionization enhanced the filtration efficiency by 40%-units during most of the operation time. When the ionization system was managed by periodically switching the ionizer polarity, the filtration efficiency against PM0.3-0.5 was maintained above 50% during half a year. Furthermore, the pressure drop of the ionizer-assisted M6 filter was 25-30% lower than that of a filter of class F7. The evaluation of various influencing factors demonstrated that (1) air moisture reduced the increase of filtration efficiency; (2) higher upstream particle concentration and air velocity decreased the filtration efficiency; and (3) the air temperature had very limited effect on the filtration efficiency.

  18. Small particle size lipid emulsions, satiety and energy intake in lean men.

    Science.gov (United States)

    Chan, Y K; Budgett, S C; MacGibbon, A K; Quek, S Y; Kindleysides, S; Poppitt, S D

    2017-02-01

    Lipid emulsions have been proposed to suppress hunger and food intake. Whilst there is no consensus on optimal structural properties or mechanism of action, small particle size (small-PS) stable emulsions may have greatest efficacy. Fabuless®, a commercial lipid emulsion reported in some studies to decrease energy intake (EI), is a small-PS, 'hard' fat emulsion comprising highly saturated palm oil base (PS, 82nm). To determine whether small-PS dairy lipid emulsions can enhance satiety, firstly, we investigated 2 'soft' fat dairy emulsions generated using dairy and soy emulsifying agents (PS, 114nm and 121nm) and a non-emulsified dairy control. Secondly, we investigated a small-PS palmolein based 'hard' fat emulsion (fractionated palm oil, PS, 104nm) and non-emulsified control. This was a 6 arm, randomized, cross-over study in 18 lean men, with test lipids delivered in a breakfast meal: (i) Fabuless® emulsion (FEM); (ii) dairy emulsion with dairy emulsifier (DEDE); (iii) dairy emulsion with soy lecithin emulsifier (DESE); (iv) dairy control (DCON); (v) palmolein emulsion with dairy emulsifier (PEDE); (vi) palmolein control (PCON). Participants rated postprandial appetite sensations using visual analogue scales (VAS), and ad libitum energy intake (EI) was measured at a lunch meal 3.5h later. Dairy lipid emulsions did not significantly alter satiety ratings or change EI relative to dairy control (DEDE, 4035kJ; DESE, 3904kJ; DCON, 3985kJ; P>0.05) nor did palm oil based emulsion relative to non-emulsified control (PEDE, 3902 kJ; PCON, 3973kJ; P>0.05). There was no evidence that small-PS dairy lipid emulsions or commercial Fabuless altered short-term appetite or food intake in lean adults. Copyright © 2016. Published by Elsevier Inc.

  19. Particle size measurements in the submicron range by the differential electromobility technique: comparison of aerosols from thermospray, ultrasonic, pneumatic and frit-type nebulizers

    Science.gov (United States)

    Clifford, Robert H.; Tan, Hsiaoming; Liu, Huiying; Montaser, Akbar; Zarrin, Fahimeh; Keady, Patricia B.

    1993-08-01

    The differential electromobility technique was used for the comparison of droplet- and particle-size distributions in the 0.02-0.8 μm range for six nebulization systems often used in inductively coupled plasma (ICP) spectrometry: a thermospray nebulizer coupled to a membrane separator (TNMS); two ultrasonic nebulizers (USNs) used with desolvation; one pneumatic nebulizer (PN) used with and without desolvation; and a frit-type nebulizer. In general, volume concentration (volume of droplets or particles per cubic centimeter of injector gas) increased with NaCl concentration, and it was greater for TNMS followed by USNs compared to other nebulizers. For the desolvated aerosol produced by PN and USN, volume concentration was found to be independent of the temperature (140-180°C) of the heating tube for the desolvation device. As the nebulizer tip temperature in thermospray nebulization was varied from 160 to 240°C, a larger volume concentration of desolvated aerosol was produced. Size distributions shifted towards larger particles with increasing NaCl concentration. The implications of these observations in plasma spectrochemical measurements are discussed.

  20. Lipid-soluble smoke particles damage endothelial cells and reduce endothelium-dependent dilatation in rat and man

    DEFF Research Database (Denmark)

    Zhang, Jin-Yan; Cao, Yong-Xiao; Xu, Cang-Bao;

    2006-01-01

    BACKGROUND: Cigarette smoking is a strong risk factor for vascular disease and known to cause dysfunction of the endothelium. However, the molecular mechanisms involved are still not fully understood. METHODS: In order to reveal the direct effects of lipid-soluble smoke particles on the endothelium......, ring segments isolated from rat mesenteric arteries and human middle cerebral arteries (MCA) obtained at autopsy were incubated for 6 to 48 hrs in the presence of dimethylsulphoxide (DMSO)-soluble particles from cigarette smoke (DSP), i.e. lipid-soluble smoke particles. The endothelial microstructure...

  1. Magneto-electrical orientation of lipid-coated graphitic micro-particles in solution

    CERN Document Server

    Nguyen, Johnny; Garcia, Isabel Llorente

    2016-01-01

    We demonstrate, for the first time, confinement of the orientation of micron-sized graphitic flakes to a well-defined plane. We orient and rotationally trap lipid-coated highly ordered pyrolytic graphite (HOPG) micro-flakes in aqueous solution using a combination of uniform magnetic and AC electric fields and exploiting the anisotropic diamagnetic and electrical properties of HOPG. Measuring the rotational Brownian fluctuations of individual oriented particles in rotational traps, we quantitatively determine the rotational trap stiffness, maximum applied torque and polarization anisotropy of the micro-flakes, as well as their dependency on the electric field frequency. Additionally, we quantify interactions of the micro-particles with adjacent glass surfaces with various surface treatments. We outline the various applications of this work, including torque sensing in biological systems.

  2. Preparation of calcium chloride-loaded solid lipid particles and heat-triggered calcium ion release

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Huangying; Kim, Jin-Chul [Kangwon National University, Chunchon (Korea, Republic of)

    2015-08-15

    CaCl{sub 2}-loaded solid lipid particles (SLPs) were prepared by a melt/emulsification/solidification method. CaCl{sub 2} microparticles (1-5 μm) could be obtained in a mortar with aid of the dispersant (Tween 80/Span80 (35/65, w/w)) when the ratio of CaCl{sub 2} to dispersant was 2 : 0.1 (w/w). SLP was prepared by dispersing 0.42 g of micronized CaCl{sub 2} particles in 2 g of molten PBSA, emulsifying the mixture at 85 .deg. C in 40 ml of Tween 20 solution (0.5% w/v), and quenching the emulsion in an ice bath. The diameter of CaCl{sub 2}-loaded SLP was 10-150 μm. The unenveloped CaCl{sub 2} could be removed by dialysis and the specific loading of CaCl{sub 2} in SLP was 0.036mg/mg. An EDS spectrum of CaCl{sub 2}-loaded SLP, which was dialyzed, showed that the unenveloped CaCl{sub 2} was completely removed. Any excipients (dispersant, Tween 20, CaCl{sub 2}) had little effect on the melting point of SLPs. No appreciable amount of Ca2+ was released in 20-50 .deg. C for 22 h. But the release degree at 60 .deg. C was significant (about 2.3%) during the same period. The matrix of the lipid particle was in a liquid state at 60 .deg. C, so CaCl{sub 2} particles could move freely and contact the surrounding water, leading to the release. At 70 .deg. C, the release degree at a given time was a few times higher than that obtained at 60 .deg. C.

  3. Modeling the effect of nano-sized polymer particles on the properties of lipid membranes

    Science.gov (United States)

    Rossi, Giulia; Monticelli, Luca

    2014-12-01

    The interaction between polymers and biological membranes has recently gained significant interest in several research areas. On the biomedical side, dendrimers, linear polyelectrolytes, and neutral copolymers find application as drug and gene delivery agents, as biocidal agents, and as platforms for biological sensors. On the environmental side, plastic debris is often disposed of in the oceans and gets degraded into small particles; therefore concern is raising about the interaction of small plastic particles with living organisms. From both perspectives, it is crucial to understand the processes driving the interaction between polymers and cell membranes. In recent times progress in computer technology and simulation methods has allowed computational predictions on the molecular mechanism of interaction between polymeric materials and lipid membranes. Here we review the computational studies on the interaction between lipid membranes and different classes of polymers: dendrimers, linear charged polymers, polyethylene glycol (PEG) and its derivatives, polystyrene, and some generic models of polymer chains. We conclude by discussing some of the technical challenges in this area and future developments.

  4. Characterization of submicron particles influenced by mixed biogenic and anthropogenic emissions using high-resolution aerosol mass spectrometry: results from CARES

    Directory of Open Access Journals (Sweden)

    A. Setyan

    2012-09-01

    Full Text Available An Aerodyne high resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS was deployed during the Carbonaceous Aerosols and Radiative Effects Study (CARES that took place in northern California in June 2010. We present results obtained at Cool (denoted as the T1 site of the project in the foothills of the Sierra Nevada Mountains, where intense biogenic emissions are periodically mixed with urban outflow transported by daytime southwesterly winds from the Sacramento metropolitan area. During this study, the average mass loading of submicrometer particles (PM1 was 3.0 μg m−3, dominated by organics (80% and sulfate (9.9%. The organic aerosol (OA had a nominal formula of C1H1.38N0.004OM0.44, thus an average organic mass-to-carbon (OM/OC ratio of 1.70. Two distinct oxygenated OA factors were identified via Positive matrix factorization (PMF of the high-resolution mass spectra of organics. The more oxidized MO-OOA (O/C = 0.54 was interpreted as a surrogate for secondary OA (SOA influenced by biogenic emissions whereas the less oxidized LO-OOA (O/C = 0.42 was found to represent SOA formed in photochemically processed urban emissions. LO-OOA correlated strongly with ozone and MO-OOA correlated well with two 1st generation isoprene oxidation products (methacrolein and methyl vinyl ketone, indicating that both SOAs were relatively fresh. A hydrocarbon like OA (HOA factor was also identified, representing primary emissions mainly due to local traffic. On average, SOA (= MO-OOA + LO-OOA accounted for 91% of the total OA mass and 72% of the PM1 mass observed at Cool. Twenty three periods of urban plumes from T0 (Sacramento to T1 (Cool were identified using the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem. The average PM1 mass loading was considerably higher in urban plumes than in air masses dominated by biogenic SOA. The change in OA

  5. An ABCA1-independent pathway for recycling a poorly lipidated 8.1 nm apolipoprotein E particle from glia

    Science.gov (United States)

    Fan, Jianjia; Stukas, Sophie; Wong, Charmaine; Chan, Jennifer; May, Sharon; DeValle, Nicole; Hirsch-Reinshagen, Veronica; Wilkinson, Anna; Oda, Michael N.; Wellington, Cheryl L.

    2011-01-01

    Lipid transport in the brain is coordinated by glial-derived lipoproteins that contain apolipoprotein E (apoE) as their primary protein. Here we show that apoE is secreted from wild-type (WT) primary murine mixed glia as nascent lipoprotein subspecies ranging from 7.5 to 17 nm in diameter. Negative-staining electron microscropy (EM) revealed rouleaux, suggesting a discoidal structure. Potassium bromide (KBr) density gradient ultracentrifugation showed that all subspecies, except an 8.1 nm particle, were lipidated. Glia lacking the cholesterol transporter ABCA1 secreted only 8.1 nm particles, which were poorly lipidated and nondiscoidal but could accept lipids to form the full repertoire of WT apoE particles. Receptor-associated-protein (RAP)-mediated inhibition of apoE receptor function blocked appearance of the 8.1 nm species, suggesting that this particle may arise through apoE recycling. Selective deletion of the LDL receptor (LDLR) reduced the level of 8.1 nm particle production by approximately 90%, suggesting that apoE is preferentially recycled through the LDLR. Finally, apoA-I stimulated secretion of 8.1 nm particles in a dose-dependent manner. These results suggest that nascent glial apoE lipoproteins are secreted through multiple pathways and that a greater understanding of these mechanisms may be relevant to several neurological disorders. PMID:21705806

  6. Safety and pharmacokinetics of a solid lipid curcumin particle formulation in osteosarcoma patients and healthy volunteers.

    Science.gov (United States)

    Gota, Vikram S; Maru, Girish B; Soni, Tejal G; Gandhi, Tejal R; Kochar, Nitin; Agarwal, Manish G

    2010-02-24

    Curcumin is the lipid-soluble antioxidant compound obtained from the rhizome of Curcuma longa Linn, also known as turmeric. Curcumin targets multiple chemotherapeutic and inflammatory pathways and has demonstrated safety and tolerability in humans, supporting its potential as a therapeutic agent; however, the clinical literature lacks conclusive evidence supporting its use as a therapeutic agent due to its low bioavailability in humans. The purpose of this study was to quantify plasma levels of free curcumin after dosing of a solid lipid curcumin particle (SLCP) formulation versus unformulated curcumin in healthy volunteers and to determine its tolerability and dose-plasma concentration relationship in late-stage osteosarcoma patients. Doses of 2, 3, and 4 g of SLCP were evaluated in 11 patients with osteosarcoma. Plasma curcumin levels were measured using a validated high-performance liquid chromatography method. The limit of detection of the assay was 1 ng/mL of curcumin. In healthy subjects, the mean peak concentration of curcumin achieved from dosing 650 mg of SLCP was 22.43 ng/mL, whereas plasma curcumin from dosing an equal quantity of unformulated 95% curcuminoids extract was not detected. In both healthy individuals and osteosarcoma patients, high interindividual variability in pharmacokinetics and nonlinear dose dependency was observed, suggesting potentially complex absorption kinetics. Overall, good tolerability was noted in both healthy and osteosarcoma groups.

  7. Lipid-soluble cigarette smoking particles induce expression of inflammatory and extracellular-matrix-related genes in rat cerebral arteries

    DEFF Research Database (Denmark)

    Vikman, Petter; Xu, Cang-Bao; Edvinsson, Lars

    2009-01-01

    AIMS: Cigarette smoking is one of the strongest risk factors for stroke. However, the underlying molecular mechanisms that smoke leads to the pathogenesis of stroke are incompletely understood. METHODS: Dimethyl sulfoxide (DMSO)-soluble (lipid-soluble) cigarette smoking particles (DSP) were extra...

  8. Zirconia nanocrystals as submicron level biological label

    Science.gov (United States)

    Smits, K.; Liepins, J.; Gavare, M.; Patmalnieks, A.; Gruduls, A.; Jankovica, D.

    2012-08-01

    Inorganic nanocrystals are of increasing interest for their usage in biology and pharmacology research. Our interest was to justify ZrO2 nanocrystal usage as submicron level biological label in baker's yeast Saccharomyces cerevisia culture. For the first time (to our knowledge) images with sub micro up-conversion luminescent particles in biologic media were made. A set of undoped as well as Er and Yb doped ZrO2 samples at different concentrations were prepared by sol-gel method. The up-conversion luminescence for free standing and for nanocrystals with baker's yeast cells was studied and the differences in up-conversion luminescence spectra were analyzed. In vivo toxic effects of ZrO2 nanocrystals were tested by co-cultivation with baker's yeast.

  9. Investigating the correlation between in vivo absorption and in vitro release of fenofibrate from lipid matrix particles in biorelevant medium.

    Science.gov (United States)

    Borkar, Nrupa; Xia, Dengning; Holm, René; Gan, Yong; Müllertz, Anette; Yang, Mingshi; Mu, Huiling

    2014-01-23

    Lipid matrix particles (LMP) may be used as better carriers for poorly water-soluble drugs than liquid lipid carriers because of reduced drug mobilization in the formulations. However, the digestion process of solid lipid particles and their effect on the absorption of poorly water-soluble drugs are not fully understood. This study aimed at investigating the effect of particle size of LMP on drug release in vitro as well as absorption in vivo in order to get a better understanding on the effect of degradation of lipid particles on drug solubilisation and absorption. Fenofibrate, a model poorly water-soluble drug, was incorporated into LMP in this study using probe ultrasound sonication. The resultant LMP were characterised in terms of particle size, size distribution, zeta potential, entrapment efficiency, in vitro lipolysis and in vivo absorption in rat model. LMP of three different particle sizes i.e. approximately 100 nm, 400 nm, and 10 μm (microparticles) were produced with high entrapment efficiencies. The in vitro lipolysis study showed that the recovery of fenofibrate in the aqueous phase for 100 nm and 400 nm LMP was significantly higher (pdigested to a larger extent due to greater specific surface area. The 100 nm LMP showed faster initial digestion followed by 400 nm LMP and microparticles. The area under the plasma concentration-time curve (AUC) following oral administration of 100 nm LMP was significantly higher (pabsorption and the in vitro response was observed. The recovery (%) of fenofibrate partitioning into the aqueous phase during in vitro lipolysis and the AUC of plasma concentration-time curve of fenofibric acid was in the order of 100 nm LMP>microparticles>control. In summary, the present study demonstrated the particle size dependence of bioavailability of fenofibrate loaded LMP in rat model which correlates well with the in vitro drug release performed in the biorelevant medium.

  10. On the acoustic properties of vaporized submicron perfluorocarbon droplets.

    Science.gov (United States)

    Reznik, Nikita; Lajoinie, Guillaume; Shpak, Oleksandr; Gelderblom, Erik C; Williams, Ross; de Jong, Nico; Versluis, Michel; Burns, Peter N

    2014-06-01

    The acoustic characteristics of microbubbles created from vaporized submicron perfluorocarbon droplets with fluorosurfactant coating are examined. Utilizing ultra-high-speed optical imaging, the acoustic response of individual microbubbles to low-intensity diagnostic ultrasound was observed on clinically relevant time scales of hundreds of milliseconds after vaporization. It was found that the vaporized droplets oscillate non-linearly and exhibit a resonant bubble size shift and increased damping relative to uncoated gas bubbles due to the presence of coating material. Unlike the commercially available lipid-coated ultrasound contrast agents, which may exhibit compression-only behavior, vaporized droplets may exhibit expansion-dominated oscillations. It was further observed that the non-linearity of the acoustic response of the bubbles was comparable to that of SonoVue microbubbles. These results suggest that vaporized submicron perfluorocarbon droplets possess the acoustic characteristics necessary for their potential use as ultrasound contrast agents in clinical practice.

  11. Recent Advances in Analytical Methods on Lipoprotein Subclasses: Calculation of Particle Numbers from Lipid Levels by Gel Permeation HPLC Using "Spherical Particle Model".

    Science.gov (United States)

    Okazaki, Mitsuyo; Yamashita, Shizuya

    2016-01-01

    Recently, we developed an analytical method for determining the lipid levels and particle numbers in lipoprotein subclasses covering a wide size range from chylomicrons to small high density lipoproteins, by using gel permeation high-performance liquid chromatography (GP-HPLC). The challenges in analytical methods on lipoprotein subclasses have been addressed from 1980 by Hara and Okazaki using commercial TSK gel permeation columns. Later, the improvements in the hardware, separation and detection of lipoproteins, and the data processing software, using a Gaussian distribution approximation to calculate lipid levels of lipoprotein subclasses, have been extensively utilized in these analytical methods for over thirty years. In this review, we describe on the recent advances in analytical methods on lipoprotein subclasses based on various techniques, and the calculation of particle numbers from lipid levels by GPHPLC using the "spherical particle model". Free/ester ratio of cholesterol in particular lipoprotein subclass was accurately estimated from triglyceride, total cholesterol (free and esterified) and the size of the particle based on this model originally proposed by Shen and Kezdy.

  12. Submicron magnetic core conducting polypyrrole polymer shell: Preparation and characterization.

    Science.gov (United States)

    Tenório-Neto, Ernandes Taveira; Baraket, Abdoullatif; Kabbaj, Dounia; Zine, Nadia; Errachid, Abdelhamid; Fessi, Hatem; Kunita, Marcos Hiroiuqui; Elaissari, Abdelhamid

    2016-04-01

    Magnetic particles are of great interest in various biomedical applications, such as, sample preparation, in vitro biomedical diagnosis, and both in vivo diagnosis and therapy. For in vitro applications and especially in labs-on-a-chip, microfluidics, microsystems, or biosensors, the needed magnetic dispersion should answer various criteria, for instance, submicron size in order to avoid a rapid sedimentation rate, fast separations under an applied magnetic field, and appreciable colloidal stability (stable dispersion under shearing process). Then, the aim of this work was to prepare highly magnetic particles with a magnetic core and conducting polymer shell particles in order to be used not only as a carrier, but also for the in vitro detection step. The prepared magnetic seed dispersions were functionalized using pyrrole and pyrrole-2-carboxylic acid. The obtained core-shell particles were characterized in terms of particle size, size distribution, magnetization properties, FTIR analysis, surface morphology, chemical composition, and finally, the conducting property of those particles were evaluated by cyclic voltammetry. The obtained functional submicron highly magnetic particles are found to be conducting material bearing function carboxylic group on the surface. These promising conducting magnetic particles can be used for both transport and lab-on-a-chip detection.

  13. Effect of Agglomeration on the Analysis of Particle Size Distribution of 5A Submicron Zeolite%团聚对亚微米5A分子筛粒度分析的影响

    Institute of Scientific and Technical Information of China (English)

    施露; 崔群; 王海燕

    2013-01-01

    为了考察小晶粒分子筛团聚对亚微米级5A分子筛粒度分布结果的影响以及适宜的测定条件,实验以水为分散介质,六偏磷酸钠为分散剂,在超声波辅助作用下,用电位/粒度分析仪测定研究了试样浓度、分散剂用量和超声时间对亚微米级5A分子筛分散性的影响.结果表明,当分子筛含量大于5 g/L时,晶粒团聚现象严重,粒度分布呈现单峰(假象),导致粒度测量结果偏大;加入少量(0.005~0.195g/L)的六偏磷酸钠,有缓解晶粒团聚作用,可将较大团聚粒子(大于2.8μm)分散为较小粒子(1.3μm左右),少量团聚粒子分散成单个晶粒,可测得较小晶粒粒径;超声作用可使较大团聚粒子(0.85~2.80 μm)分布峰强度降低,相对较小粒子(0.30~0.85μm)分布峰强度增加.超声时间不宜太长,否则将加剧粒子间团聚,使得测定粒径偏大.当试样中5A分子筛含量为5g/L,六偏磷酸钠浓度0.195g/L、超声时间4 min条件下,测得5A分子筛试样粒径分布0.25~0.80 μm,峰顶对应粒径为0.473μm,中位径(d50)为0.784μm,与电镜分析结果一致,说明是较为准确的粒度分析方法.%This paper discusses the effect of small grain agglomeration on the particle size distribution (PSD) of 5 A submicron zeolite and the appropriate measuring methods. Water and sodium hexametaphosphate were chosen as a disperse medium and a dispersant, respectively. The influences of zeolite concentration, dispersant dosage and time of ultrasonic treatment on the dispersion state were studied by a potential/particle size analyzer with ultrasonic treatment. Results show that when zeolite concentration is more than 5 g/L, the PSD appears to be a unimodal distribution (false appearance), leading to a large measured size due to severe agglomeration. A small amount of sodium hexametaphosphate (0.005-0.195 g/L) additive can alleviate the agglomeration by dispersing most large agglomerated particles (more than 2.8 μm) into

  14. Moisture content and particle size of dehydrated egg yolk affect lipid and cholesterol extraction using supercritical carbon dioxide.

    Science.gov (United States)

    Froning, G W; Wehling, R L; Cuppett, S; Niemann, L

    1998-11-01

    Egg yolk was spray-dried under conditions to produce a small particle size powder and a large particle size powder. Particle size was determined using a Nikon Optiophot microscope. Spray-dried egg yolk was also adjusted to various moisture levels as follows: control (2 to 4% moisture), 7% moisture, and 12% moisture. Supercritical carbon dioxide extraction (SCE) of each of these moisture treatments at 45 C/306 atm using 30 g CO2/g of sample was completed. For the particle size study, 45 g CO2/g of sample at 45 C/306 atm was utilized. Particle size exhibited a significant effect on cholesterol and lipids extracted using SCE. As moisture content of dried egg yolk increased to 7%, there was a significant increase in lipids extracted using supercritical carbon dioxide. Moisture content had no significant effect on cholesterol extraction. After extracting SCE higher moisture spray-dried egg yolk, sponge cake volume was significantly reduced compared to that of the control. The reduced sponge cake volume may be due to protein denaturation.

  15. Polyhydroxy surfactants for the formulation of lipid nanoparticles (SLN and NLC): effects on size, physical stability and particle matrix structure.

    Science.gov (United States)

    Kovacevic, A; Savic, S; Vuleta, G; Müller, R H; Keck, C M

    2011-03-15

    The two polyhydroxy surfactants polyglycerol 6-distearate (Plurol(®)Stearique WL1009 - (PS)) and caprylyl/capryl glucoside (Plantacare(®) 810 - (PL)) are a class of PEG-free stabilizers, made from renewable resources. They were investigated for stabilization of aqueous solid lipid nanoparticle (SLN) and nanostructured lipid carrier (NLC) dispersions. Production was performed by high pressure homogenization, analysis by photon correlation spectroscopy (PCS), laser diffraction (LD), zeta potential measurements and differential scanning calorimetry (DSC). Particles were made from Cutina CP as solid lipid only (SLN) and its blends with Miglyol 812 (NLC, the blends containing increasing amounts of oil from 20% to 60%). The obtained particle sizes were identical for both surfactants, about 200 nm with polydispersity indices below 0.20 (PCS), and unimodal size distribution (LD). All dispersions with both surfactants were physically stable for 3 months at room temperature, but Plantacare (PL) showing a superior stability. The melting behaviour and crystallinity of bulk lipids/lipid blends were compared to the nanoparticles. Both were lower for the nanoparticles. The crystallinity of dispersions stabilized with PS was higher, the zeta potential decreased with storage time associated with this higher crystallinity, and leading to a few, but negligible larger particles. The lower crystallinity particles stabilized with PL remained unchanged in zeta potential (about -50 mV) and in size. These data show that surfactants have a distinct influence on the particle matrix structure (and related stability and drug loading), to which too little attention was given by now. Despite being from the same surfactant class, the differences on the structure are pronounced. They are attributed to the hydrophobic-lipophilic tail structure with one-point anchoring in the interface (PL), and the loop conformation of PS with two hydrophobic anchor points, i.e. their molecular structure and its

  16. Development of a Lipid Particle for β-Carotene Encapsulation Using a Blend of Tristearin and Sunflower Oil: Choice of Lipid Matrix and Evaluation of Shelf Life of Dispersions

    Directory of Open Access Journals (Sweden)

    Graziela V. L. Gomes

    2013-01-01

    Full Text Available Solid lipid particles are colloidal carriers that have been studied for almost 20 years in the pharmaceutical field and recently have been investigated by food researchers due to their capacity to enhance the incorporation of lipophilic bioactives and their bioavailability in aqueous formulations. The aims of this study are to choose a suitable lipid matrix to produce solid lipid particles, which would be used to encapsulate β-carotene, and to evaluate the capacity of dispersions to protect the incorporated carotenoid. Bulk lipid mixtures of tristearin and sunflower oil were analysed by differential scanning calorimetry and wide angle X-ray diffraction, and the mixture with the highest degree of structural disorganisation was chosen. β-Carotene was then encapsulated in solid lipid particles produced with this mixture, composed of 70 % tristearin and 30 % sunflower oil (6 % total lipid and stabilised with hydrogenated soy lecithin and Tween 80 (3 % total surfactant by hot pressure homogenisation. Two types of particles were produced, using one or two passages in the homogenisation step. Average particle size, zeta potential, thermal behaviour, crystallinity and β-carotene concentration were monitored over 4 months of storage (under refrigerated conditions. The results showed minor differences between the systems in terms of size distribution, although the particles produced with one passage through the homogeniser were slightly more efficient at protecting the β-carotene from degradation and also suffered few microstructural alterations after 4 months.

  17. Analysis of submicron-sized niflumic acid crystals prepared by electrospray crystallization

    NARCIS (Netherlands)

    Ambrus, R.; Radacsi, N.; Szunyogh, T.; Heijden, A.E.D.M. van der; Horst, J.H. ter; Szabó-Révész, P.

    2013-01-01

    Interest in submicron-sized drug particles has emerged from both laboratory and industrial perspectives in the last decade. Production of crystals in the nano size scale offers a novel way to particles for drug formulation solving formulation problems of drugs with low solubility in class II of the

  18. Solid lipid nanoparticles: A drug carrier system

    Directory of Open Access Journals (Sweden)

    Rashmi R Kokardekar

    2011-01-01

    Full Text Available Solid lipid nanoparticles (SLN are a type of nanoparticles. They are submicron colloidal carriers which are composed of physiological lipids, dispersed in water or in aqueous surfactant solutions. SLN have wide range of advantages over other types of nanoparticles. These include availability of large-scale production methods and no signs of cytotoxicity, which are main hindrances in the application of other types of nanoparticles. Hot and cold homogenization techniques are mainly employed for its production. They are mainly evaluated on the basis of their drug release profile and particle internal structure. The products based on SLN are under development. They have a very wide range of applications in cosmetics and pharmaceuticals. They can be applied for any purpose, for which nanoparticles have a distinct advantage. Thus, SLN can be used extensively as an alternative to the existing drug carrier systems, providing more flexibility with respect to the area of applications and also aspects for commercialization.

  19. Solid lipid particles for oral delivery of peptide and protein drugs III - the effect of fed state conditions on the in vitro release and degradation of desmopressin

    DEFF Research Database (Denmark)

    Christophersen, Philip C; Vaghela, Dimple; Müllertz, Anette;

    2014-01-01

    of oleic acid glycerides accelerated the release of desmopressin significantly from all solid lipid particles both in the presence and absence of lipase. The presence of oleic acid glycerides also reduced the degradation rate of desmopressin, probably due to the interactions between the lipids...

  20. Growth Mechanism of Lipid-Based Nanodiscs -- a Model Membrane for Studying Kinetics of Particle Coalescence

    Science.gov (United States)

    Nieh, Mu-Ping; Dizon, Anthony; Li, Ming; Hu, Andrew; Fan, Tai-Hsi

    2012-02-01

    Lipid-based nanodiscs composed of long- and short- chain lipids [namely, dimyristoyl phosphatidylcholine (DMPC), dimyristoyl phosphatidylglycerol (DMPG) and dihexanoyl phosphatidylcholine (DHPC)] constantly form at high lipid concentrations and at low temperatures (i.e., below the melting transition temperature of DMPC, TM). The initial size of these nanodiscs (at high total lipid concentration, CL> 20 wt.%) is relatively uniform and of similar dimension (according to dynamic light scattering and small angle neutron scattering experiments), seemingly independent of thermal history. Upon dilution, the nanodiscs slowly coalesce and grow in size with time irreversibly. Our preliminary result shows that the growth rate strongly depends on several parameters such as charge density, CL and temperature. We have also found that the nanodisc coalescence is a reaction limit instead of diffusion limit process through a time-resolved study.

  1. Tracking single particles on supported lipid membranes: multi-mobility diffusion and nanoscopic confinement

    CERN Document Server

    ,

    2013-01-01

    Supported lipid bilayers have been studied intensively over the past two decades. In this work, we study the diffusion of single gold nanoparticles (GNPs) with diameter of 20 nm attached to GM1 ganglioside or DOPE lipids at different concentrations in supported DOPC bilayers. The indefinite photostability of GNPs combined with the high sensitivity of interferometric scattering microscopy (iSCAT) allows us to achieve 1.9 nm spatial precision at 1 ms temporal resolution, while maintaining long recording times. Our trajectories visualize strong transient confinements within domains as small as 20 nm, and the statistical analysis of the data reveals multiple mobilities and deviations from normal diffusion. We present a detailed analysis of our findings and provide interpretations regarding the effect of the supporting substrate and GM1 clustering. We also comment on the use of high-speed iSCAT for investigating diffusion of lipids, proteins or viruses in lipid membranes with unprecedented spatial and temporal res...

  2. Proceedings of submicron multiphase materials

    Energy Technology Data Exchange (ETDEWEB)

    Baney, R.; Gilliom, L.; Hirano, S.I.; Schmidt, H.

    1992-01-01

    This book contains the papers presented at Symposium R of the spring 1992 Materials Research Society meeting held in San Francisco, California. The title of the symposium, Submicron Multiphase Materials, was selected by the organizers to encompass the realm of composite materials from those smaller than conventional fiber matrix composites to those with phase separation dimensions approaching molecular dimensions. The development of composite materials is as old as the development of materials. Humans quickly learned that, by combining materials, the best properties of each can be realized and that, in fact, synergistic effects often arise. For example, chopped straw was used by the Israelites to limit cracking in bricks. The famed Japanese samurai swords were multilayers of hard oxide and tough ductile materials. One also finds in nature examples of composite materials. These range form bone to wood, consisting of a hard phase which provides strength and stiffness and a softer phase for toughness. Advanced composites are generally thought of as those which are based on a high modulus, discontinuous, chopped or woven fiber phase and a continuous polymer phase. In multiphase composites, dimensions can range from meters in materials such as steel rod-reinforced concrete structures to angstroms. In macrophase separated composite materials, properties frequently follow the rule of mixtures with the properties approximating the arithmetic mean of the properties of each individual phase, if there is good coupling between the phases. As the phases become smaller, the surface to volume ratio grows in importance with respect to properties. Interfacial and interphase phenomena being to dominate. Surface free energies play an ever increasing role in controlling properties. In recent years, much research in materials science has been directed at multiphase systems where phase separations are submicron in at least some dimension.

  3. Quantitative Lipid Droplet Proteome Analysis Identifies Annexin A3 as a Cofactor for HCV Particle Production

    Directory of Open Access Journals (Sweden)

    Kathrin Rösch

    2016-09-01

    Full Text Available Lipid droplets are vital to hepatitis C virus (HCV infection as the putative sites of virion assembly, but morphogenesis and egress of virions remain ill defined. We performed quantitative lipid droplet proteome analysis of HCV-infected cells to identify co-factors of that process. Our results demonstrate that HCV disconnects lipid droplets from their metabolic function. Annexin A3 (ANXA3, a protein enriched in lipid droplet fractions, strongly impacted HCV replication and was characterized further: ANXA3 is recruited to lipid-rich fractions in HCV-infected cells by the viral core and NS5A proteins. ANXA3 knockdown does not affect HCV RNA replication but severely impairs virion production with lower specific infectivity and higher density of secreted virions. ANXA3 is essential for the interaction of viral envelope E2 with apolipoprotein E (ApoE and for trafficking, but not lipidation, of ApoE in HCV-infected cells. Thus, we identified ANXA3 as a regulator of HCV maturation and egress.

  4. Dry powder inhaler formulation of lipid-polymer hybrid nanoparticles via electrostatically-driven nanoparticle assembly onto microscale carrier particles.

    Science.gov (United States)

    Yang, Yue; Cheow, Wean Sin; Hadinoto, Kunn

    2012-09-15

    Lipid-polymer hybrid nanoparticles have emerged as promising nanoscale carriers of therapeutics as they combine the attractive characteristics of liposomes and polymers. Herein we develop dry powder inhaler (DPI) formulation of hybrid nanoparticles composed of poly(lactic-co-glycolic acid) and soybean lecithin as the polymer and lipid constituents, respectively. The hybrid nanoparticles are transformed into inhalable microscale nanocomposite structures by a novel technique based on electrostatically-driven adsorption of nanoparticles onto polysaccharide carrier particles, which eliminates the drawbacks of conventional techniques based on controlled drying (e.g. nanoparticle-specific formulation, low yield). First, we engineer polysaccharide carrier particles made up of chitosan cross-linked with tripolyphosphate and dextran sulphate to exhibit the desired aerosolization characteristics and physical robustness. Second, we investigate the effects of nanoparticle to carrier mass ratio and salt inclusion on the adsorption efficiency, in terms of the nanoparticle loading and yield, from which the optimal formulation is determined. Desorption of the nanoparticles from the carrier particles in phosphate buffer saline is also examined. Lastly, we characterize aerosolization efficiency of the nanocomposite product in vitro, where the emitted dose and respirable fraction are found to be comparable to the values of conventional DPI formulations.

  5. Massively parallel and highly quantitative single-particle analysis on interactions between nanoparticles on supported lipid bilayer.

    Science.gov (United States)

    Lee, Young Kwang; Kim, Sungi; Oh, Jeong-Wook; Nam, Jwa-Min

    2014-03-12

    Observation of individual single-nanoparticle reactions provides direct information and insight for many complex chemical, physical, and biological processes, but this is utterly challenging with conventional high-resolution imaging techniques on conventional platforms. Here, we developed a photostable plasmonic nanoparticle-modified supported lipid bilayer (PNP-SLB) platform that allows for massively parallel in situ analysis of the interactions between nanoparticles with single-particle resolution on a two-dimensional (2D) fluidic surface. Each particle-by-particle PNP clustering process was monitored in real time and quantified via analysis of individual particle diffusion trajectories and single-particle-level plasmonic coupling. Importantly, the PNP-SLB-based nanoparticle cluster growth kinetics result was fitted well. As an application example, we performed a DNA detection assay, and the result suggests that our approach has very promising sensitivity and dynamic range (high attomolar to high femtomolar) without optimization, as well as remarkable single-base mismatch discrimination capability. The method shown herein can be readily applied for many different types of intermolecular and interparticle interactions and provide convenient tools and new insights for studying dynamic interactions on a highly controllable and analytical platform.

  6. Lipid-soluble cigarette smoking particles induce expression of inflammatory and extracellular-matrix-related genes in rat cerebral arteries

    DEFF Research Database (Denmark)

    Vikman, Petter; Xu, Cang-Bao; Edvinsson, Lars

    2009-01-01

    AIMS: Cigarette smoking is one of the strongest risk factors for stroke. However, the underlying molecular mechanisms that smoke leads to the pathogenesis of stroke are incompletely understood. METHODS: Dimethyl sulfoxide (DMSO)-soluble (lipid-soluble) cigarette smoking particles (DSP) were...... extracted from cigarette smoke (0.8 mg nicotine per cigarette; Marlboro). Rat cerebral arteries were isolated and organ cultured in the presence of DSP (0.2 microl/ml, equivalent to the plasma level in smokers) for 24 h. The expression of matrix metalloproteinase 9 and 13 (MMP9 and MMP13), angiotensin...

  7. Characteristics of Submicron Aerosols in 2013 summer of Beijing

    Science.gov (United States)

    Guo, Song; Hu, Min; Shang, Dongjie; Zheng, Jing; Du, Zhuofei; Wu, Yusheng; Lu, Sihua; Zeng, Limin; Zhang, Renyi

    2016-04-01

    To characterize the air pollution of North China Plain of China, CAREBEIJING-2013 field campaign (Campaigns of Air quality REsearch in BEIJING and surrounding region) was conducted in summer of 2013. Submicron aerosols were measured at an urban site PKU (Peking University, 39° 59'21"N, 116° 18'25"E) from July 28th to September 31st 2013. A suite of integrated instruments was used to measure the size distribution, effective density and hygroscopicity of ambient particles. The chemical composition of submicron particles were measured by using an Aerodyne High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) (Billerica, MA, USA). The average PM2.5 concentration was 73.0±70.7 μg m-3 during the measurement. The particulate pollution showed distinct 4-7 days cycles controlled by the meteorological conditions. Each cycle started with low PM2.5 mass concentrations (air mass was from relatively clean mountainous area. The particle number concentrations were high, but and the sizes were small (60 μg day-1, and the particle mean diameter grew to >100 nm. It is interesting to note that the mean diameters showed similar trend to PM2.5 mass concentrations, indicating the particle pollution attributed to the growth of the newly formed small particles. During the measurement, the average particle densities are between 1.3-1.5 g cm-3, indicating organics and sulfate were dominant in the particles. The densities of smaller particles, i.e. 46 nm, 81nm, showed single peak at 1.3-1.5 g cm-3, indicating the particles are internal mixed sulfate and organics. While the 150nm and 240 nm particle densities exhibited bimodal distribution with an additional small peak at ˜1.1 g cm-3, which is considered as external mixed organic particles or aged soot particles. The particle hygroscopic growth factor for all the measured sizes at RH of 90% showed bimodal distribution, attributing to external mixed organics (or aged soot) and internal mixed organics and sulfate. Both the

  8. Mono-ubiquitylated ORF45 Mediates Association of KSHV Particles with Internal Lipid Rafts for Viral Assembly and Egress.

    Directory of Open Access Journals (Sweden)

    Xin Wang

    2015-12-01

    Full Text Available Herpesviruses acquire their envelope by budding into the lumen of cytoplasmic membrane vesicles. This process is initiated by component(s on viral particles, which recognize the budding site where the viral glycoproteins are present and recruit cellular cargo transport and sorting machinery to the site to complete the budding process. Proteins in the tegument layer, connecting capsid and envelope, are candidates for the recognition of budding sites on vesicle membrane and induction of budding and final envelopment. We examined several outer and matrix tegument proteins of Kaposi's sarcoma-associated herpesvirus (KSHV and found that ORF45 associates with lipid rafts (LRs of cellular membrane. LRs are membrane micro-domains, which have been implicated as relay stations in intracellular signaling and transport including viral entry and virion assembly. The ability of ORF45 to target LR is dependent on the mono-ubiquitylation of ORF45 at Lys297 as the mutation at Lys297 (K297R abolished LR-association of ORF45. The K297R mutation also impairs ORF45 and viral particle co-localization with trans-Golgi network and endosomes, but facilitates ORF45 and viral particles co-localizing with lysosomes. More importantly, the recombinant KSHV carrying ORF45 K297R mutant (BAC-K297R was found severely defective in producing mature and infectious virion particles in comparison to wild type KSHV (BAC16. Taken together, our results reveal a new function of KSHV tegument protein ORF45 in targeting LR of host cell membrane, promoting viral particles co-localization with trans-Golgi and endosome vesicles and facilitating the maturation and release of virion particles, suggesting that ORF45 plays a role in bringing KSHV particles to the budding site on cytoplasmic vesicle membrane and triggering the viral budding process for final envelopment and virion maturation.

  9. Microstructures and properties of cold drawn and annealed submicron crystalline Cu-5%Cr alloy

    Institute of Scientific and Technical Information of China (English)

    HE Wen-xiong; YU Yang; WANG Er-de; SUN Hong-fei; HU Lian-xi; CHEN Hui

    2009-01-01

    The microstructures and properties after cold drawing and subsequent annealing of submicron crystalline Cu-5%Cr (mass fraction) alloy were investigated. The results show that, the microstructure of submicron crystalline Cu-5%Cr can be further refined by cold drawing. After cold drawing, the grains of Cu-5%Cr alloy with grain size of 400-500 nm can be refined to be cellular structures and subgrains with size of 100-200 nm. Both strength and ductility of Cu-5%Cr alloy can be enhanced by cold drawing, and the optimal mechanical properties can be achieved with drawing deformation increasing. It is suggested that dislocation glide is still the main mechanism in plastic deformation of submicron crystalline Cu-5%Cr, but grain boundary slide and diffusion may play more and more important roles with drawing deformation increasing. When the cold drawn Cu-5%Cr wires are annealed at 550 ℃, fine recrystal grains with grain size of 200-300 nm can be obtained. Furthermore, there are lots of fine Cr particles precipitated during annealing, by which the recrystallization softening temperatures of the cold drawn Cu-5%Cr wires can be increased to 480-560 ℃. Due to the fact that Cr particles have the effect of restricting Cu grains growth, a favorable structural thermal stability of the submicron crystalline Cu-5%Cr can be achieved, and the submicron grained microstructure can be retained at high temperature annealing.

  10. Effect of self-assembly of fullerene nano-particles on lipid membrane.

    Directory of Open Access Journals (Sweden)

    Saiqun Zhang

    Full Text Available Carbon nanoparticles can penetrate the cell membrane and cause cytotoxicity. The diffusion feature and translocation free energy of fullerene through lipid membranes is well reported. However, the knowledge on self-assembly of fullerenes and resulting effects on lipid membrane is poorly addressed. In this work, the self-assembly of fullerene nanoparticles and the resulting influence on the dioleoylphosphtidylcholine (DOPC model membrane were studied by using all-atom molecular dynamics simulations with explicit solvents. Our simulation results confirm that gathered small fullerene cluster can invade lipid membrane. Simulations show two pathways: 1 assembly process is completely finished before penetration; 2 assembly process coincides with penetration. Simulation results also demonstrate that in the membrane interior, fullerene clusters tend to stay at the position which is 1.0 nm away from the membrane center. In addition, the diverse microscopic stacking mode (i.e., equilateral triangle, tetrahedral pentahedral, trigonal bipyramid and octahedron of these small fullerene clusters are well characterized. Thus our simulations provide a detailed high-resolution characterization of the microscopic structures of the small fullerene clusters. Further, we found the gathered small fullerene clusters have significant adverse disturbances to the local structure of the membrane, but no great influence on the global integrity of the lipid membrane, which suggests the prerequisite of high-content fullerene for cytotoxicity.

  11. Effects of Formulation Variables on the Particle Size and Drug Encapsulation of Imatinib-Loaded Solid Lipid Nanoparticles.

    Science.gov (United States)

    Gupta, Biki; Poudel, Bijay Kumar; Pathak, Shiva; Tak, Jin Wook; Lee, Hee Hyun; Jeong, Jee-Heon; Choi, Han-Gon; Yong, Chul Soon; Kim, Jong Oh

    2016-06-01

    Imatinib (IMT), an anticancer agent, inhibits receptor tyrosine kinases and is characterized by poor aqueous solubility, extensive first-pass metabolism, and rapid clearance. The aims of the current study are to prepare imatinib-loaded solid lipid nanoparticles (IMT-SLN) and study the effects of associated formulation variables on particle size and drug encapsulation on IMT-SLN using an experimental design. IMT-SLN was optimized by use of a "combo" approach involving Plackett-Burman design (PBD) and Box-Behnken design (BBD). PBD screening resulted in the determination of organic-to-aqueous phase ratio (O/A), drug-to-lipid ratio (D/L), and amount of Tween® 20 (Tw20) as three significant variables for particle size (S z), drug loading (DL), and encapsulation efficiency (EE) of IMT-SLN, which were used for optimization by BBD, yielding an optimized criteria of O/A = 0.04, D/L = 0.03, and Tw20 = 2.50% w/v. The optimized IMT-SLN exhibited monodispersed particles with a size range of 69.0 ± 0.9 nm, ζ-potential of -24.2 ± 1.2 mV, and DL and EE of 2.9 ± 0.1 and 97.6 ± 0.1% w/w, respectively. Results of in vitro release study showed a sustained release pattern, presumably by diffusion and erosion, with a higher release rate at pH 5.0, compared to pH 7.4. In conclusion, use of the combo experimental design approach enabled clear understanding of the effects of various formulation variables on IMT-SLN and aided in the preparation of a system which exhibited desirable physicochemical and release characteristics.

  12. DRAG ON SUBMICRON NANOPARTICLE AGGREGATES

    Institute of Scientific and Technical Information of China (English)

    F.; Einar; Kruis

    2005-01-01

    A new procedure was developed for estimating the effective collision diameter of an aggregate composed of primary particles of any size. The coagulation coefficient of two oppositely charged particles was measured experimentally and compared with classic Fuchs theory, including a new method to account for particle non-sphericity. A second set of experiments were performed on well-defined nanoparticle aggregates at different stages of sintering, i.e. from the aggregate to the fully sintered stage. Here, electrical mobility was used to characterize the particle drag. The aggregates are being built from two different size-fractionated nanoparticle aerosols, the non-aggregated particles are discarded by an electrofilter and then they are passed through a furnace at concentrations low enough not to induce coagulation.

  13. The Cholestanol-Conjugated Sulfated Oligosaccharide PG545 Disrupts the Lipid Envelope of Herpes Simplex Virus Particles

    Science.gov (United States)

    Trybala, Edward; Görander, Staffan; Ekblad, Maria; Liljeqvist, Jan-Åke; Jennische, Eva; Lange, Stefan

    2015-01-01

    Herpes simplex virus (HSV) and many other viruses, including HIV, initiate infection of host cells by binding to glycosaminoglycan (GAG) chains of cell surface proteoglycans. Although GAG mimetics, such as sulfated oligo- and polysaccharides, exhibit potent antiviral activities in cultured cells, the prophylactic application of these inhibitors as vaginal microbicides failed to protect women upon their exposure to HIV. A possible explanation for this failure is that sulfated oligo- and polysaccharides exhibit no typical virucidal activity, as their interaction with viral particles is largely electrostatic and reversible and thereby vulnerable to competition with GAG-binding proteins of the genital tract. Here we report that the cholestanol-conjugated sulfated oligosaccharide PG545, but not several other sulfated oligosaccharides lacking this modification, exhibited virucidal activity manifested as disruption of the lipid envelope of HSV-2 particles. The significance of the virus particle-disrupting activity of PG545 was also demonstrated in experimental animals, as this compound, in contrast to unmodified sulfated oligosaccharide, protected mice against genital infection with HSV-2. Thus, PG545 offers a novel prophylaxis option against infections caused by GAG-binding viruses. PMID:26643323

  14. Real-time retrieval of submicron aerosol size distributions from multi-wavelength spectral extinction measurements

    Institute of Scientific and Technical Information of China (English)

    CHEN; Jiawei; YANG; Mu; FENG; Haibao; NI; Qijun

    2016-01-01

    The real-time retrieval of submicron aerosol size distributions is of major interest for applications. Based on the Mie theory,the spectral extinction method offers a simple measurement principle and a convenient optical arrangement. In contrast to the relative simplicity of the experimental measurement the retrieval of the particles size distribution and particle concentration from the spectral extinction method is difficult. Mie scattering Equation is a Fredholm Integral Equation of the First Kind. This paper develops a hybrid iterative model-dependent algorithm for on-line particle sizing from extinction spectra which is both computationally efficient and accurate. Applying the refined Mie diagnostic iterative procedures within some candidate solutions can identify the unique result accurately and rapidly enough for real time measurement. With the addition of added Gaussian noise,an average tolerance up to 5% of noise level is kept for particle size from submicron to micrometer under moderate polydispersity.

  15. Up-regulation of thromboxane A2 receptor expression by lipid soluble smoking particles through post-transcriptional mechanisms

    DEFF Research Database (Denmark)

    Zhang, Wei; Zhang, Yaping; Edvinsson, Lars

    2008-01-01

    . The present study was designed to test if lipid soluble smoking particles (DSP) enhance TxA(2) receptor (TP) expression in rat mesenteric arteries, and if intracellular mitogen-activated protein kinase (MAPK) pathways play a role. Organ culture of rat mesenteric arteries in the presence of DSP (0.2 microl...... actinomycin D, but was almost completely abolished by cycloheximide, a general translational inhibitor. Dexamethasone, a glucocorticoid, manifested a potent inhibitory effect as well. These results suggest that the up-regulation of TP receptor occurs via post-transcriptional events, and mainly translation...... are responsible for the up-regulation of TP receptor by DSP, in which enhanced translation is the major cause of the elevated protein expression and the enhanced contraction....

  16. Receptor-mediated membrane adhesion of lipid-polymer hybrid (LPH) nanoparticles studied by dissipative particle dynamics simulations.

    Science.gov (United States)

    Li, Zhenlong; Gorfe, Alemayehu A

    2015-01-14

    Lipid-polymer hybrid (LPH) nanoparticles represent a novel class of targeted drug delivery platforms that combine the advantages of liposomes and biodegradable polymeric nanoparticles. However, the molecular details of the interaction between LPHs and their target cell membranes remain poorly understood. We have investigated the receptor-mediated membrane adhesion process of a ligand-tethered LPH nanoparticle using extensive dissipative particle dynamics (DPD) simulations. We found that the spontaneous adhesion process follows a first-order kinetics characterized by two distinct stages: a rapid nanoparticle-membrane engagement, followed by a slow growth in the number of ligand-receptor pairs coupled with structural re-organization of both the nanoparticle and the membrane. The number of ligand-receptor pairs increases with the dynamic segregation of ligands and receptors toward the adhesion zone causing an out-of-plane deformation of the membrane. Moreover, the fluidity of the lipid shell allows for strong nanoparticle-membrane interactions to occur even when the ligand density is low. The LPH-membrane avidity is enhanced by the increased stability of each receptor-ligand pair due to the geometric confinement and the cooperative effect arising from multiple binding events. Thus, our results reveal the unique advantages of LPH nanoparticles as active cell-targeting nanocarriers and provide some general principles governing nanoparticle-cell interactions that may aid future design of LPHs with improved affinity and specificity for a given target of interest.

  17. Receptor-mediated membrane adhesion of lipid-polymer hybrid (LPH) nanoparticles studied by dissipative particle dynamics simulations

    Science.gov (United States)

    Li, Zhenlong; Gorfe, Alemayehu A.

    2014-12-01

    Lipid-polymer hybrid (LPH) nanoparticles represent a novel class of targeted drug delivery platforms that combine the advantages of liposomes and biodegradable polymeric nanoparticles. However, the molecular details of the interaction between LPHs and their target cell membranes remain poorly understood. We have investigated the receptor-mediated membrane adhesion process of a ligand-tethered LPH nanoparticle using extensive dissipative particle dynamics (DPD) simulations. We found that the spontaneous adhesion process follows a first-order kinetics characterized by two distinct stages: a rapid nanoparticle-membrane engagement, followed by a slow growth in the number of ligand-receptor pairs coupled with structural re-organization of both the nanoparticle and the membrane. The number of ligand-receptor pairs increases with the dynamic segregation of ligands and receptors toward the adhesion zone causing an out-of-plane deformation of the membrane. Moreover, the fluidity of the lipid shell allows for strong nanoparticle-membrane interactions to occur even when the ligand density is low. The LPH-membrane avidity is enhanced by the increased stability of each receptor-ligand pair due to the geometric confinement and the cooperative effect arising from multiple binding events. Thus, our results reveal the unique advantages of LPH nanoparticles as active cell-targeting nanocarriers and provide some general principles governing nanoparticle-cell interactions that may aid future design of LPHs with improved affinity and specificity for a given target of interest.

  18. Ultrafine particles affect the balance of endogenous pro- and anti-inflammatory lipid mediators in the lung: in-vitro and in-vivo studies

    Directory of Open Access Journals (Sweden)

    Beck-Speier Ingrid

    2012-07-01

    Full Text Available Abstract Background Exposure to ultrafine particles exerts diverse harmful effects including aggravation of pulmonary diseases like asthma. Recently we demonstrated in a mouse model for allergic airway inflammation that particle-derived oxidative stress plays a crucial role during augmentation of allergen-induced lung inflammation by ultrafine carbon particle (UfCP inhalation. The mechanisms how particle inhalation might change the inflammatory balance in the lungs, leading to accelerated inflammatory reactions, remain unclear. Lipid mediators, known to be immediately generated in response to tissue injury, might be strong candidates for priming this particle-triggered change of the inflammatory balance. Methods We hypothesize that inhalation of UfCP may disturb the balance of pro- and anti-inflammatory lipid mediators in: i a model for acute allergic pulmonary inflammation, exposing mice for 24 h before allergen challenge to UfCP inhalation (51.7 nm, 507 μg/m3, and ii an in-vitro model with primary rat alveolar macrophages (AM incubated with UfCP (10 μg/1 x 106 cells/ml for 1 h. Lungs and AM were analysed for pro- and anti-inflammatory lipid mediators, namely leukotriene B4 (LTB4, prostaglandin E2 (PGE2, 15(S-hydroxy-eicosatetraenoic acid (15(S-HETE, lipoxin A4 (LXA4 and oxidative stress marker 8-isoprostane by enzyme immunoassays and immunohistochemistry. Results In non-sensitized mice UfCP exposure induced a light non-significant increase of all lipid mediators. Similarly but significantly in rat AM all lipid mediators were induced already within 1 h of UfCP stimulation. Also sensitized and challenge mice exposed to filtered air showed a partially significant increase in all lipid mediators. In sensitized and challenged mice UfCP exposure induced highest significant levels of all lipid mediators in the lungs together with the peak of allergic airway inflammation on day 7 after UfCP inhalation. The levels of LTB4, 8-isoprostane and PGE2 were

  19. Markers of lipid oxidative damage among office workers exposed intermittently to air pollutants including nanoTiO2 particles.

    Science.gov (United States)

    Pelclova, Daniela; Zdimal, Vladimir; Kacer, Petr; Komarc, Martin; Fenclova, Zdenka; Vlckova, Stepanka; Zikova, Nadezda; Schwarz, Jaroslav; Makes, Otakar; Navratil, Tomas; Zakharov, Sergey; Bello, Dhimiter

    2017-03-01

    Nanoscale titanium dioxide (nanoTiO2) is a commercially important nanomaterial used in numerous applications. Experimental studies with nanotitania have documented lung injury and inflammation, oxidative stress, and genotoxicity. Production workers in TiO2 manufacturing with a high proportion of nanoparticles and a mixture of other air pollutants, such as gases and organic aerosols, had increased markers of oxidative stress, including DNA and protein damage, as well as lipid peroxidation in their exhaled breath condensate (EBC) compared to unexposed controls. Office workers were observed to get intermittent exposures to nanoTiO2 during their process monitoring. The aim of this study was to investigate the impact of such short-term exposures on the markers of health effects in office workers relative to production workers from the same factory. Twenty-two office employees were examined. They were occupationally exposed to (nano)TiO2 aerosol during their daily visits of the production area for an average of 14±9 min/day. Median particle number concentration in office workers while in the production area was 2.32×104/cm3. About 80% of the particles were meaning of their physiological values in the context of chronic disease development and damage-repair kinetics.

  20. Synthesis, magnetic properties, surface modification and cytotoxicity evaluation of Y{sub 3}Fe{sub 5-x}Al{sub x}O{sub 12} (0{<=}x{<=}2) garnet submicron particles for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Grasset, Fabien; Mornet, S.Stephane; Demourgues, Alain; Portier, Josik; Bonnet, Jacques; Vekris, Antoine; Duguet, Etienne E-mail: duguet@icmcb.u-bordeaux.fr

    2001-09-01

    Yttrium aluminum iron garnet Y{sub 3}Fe{sub 5-x}Al{sub x}O{sub 12} compounds were produced by the citrate gel process by varying the aluminum content x from 0 to 2. Particles with an average size of about 100 nm and a specific surface area ranging from 6 to 28 m{sup 2}/g were obtained. Curie temperatures (T{sub C}) were determined from the temperature dependence of the field-cooled magnetization (FCM) and the remnant magnetization (REM) and range from -40 deg. C to 280 deg. C. According to the magnetic moment variation, the aluminum cation seems to replace the iron cation in the tetrahedral site for compounds with x<0.7. 3-Aminopropyltrimethoxysilane ({gamma}-APS) was grafted onto the particles surface and its presence confirmed by infra-red spectroscopy. Cytotoxicity assays were carried out during a period of 13 days using human microglia and rat glioblastoma cell lines. The presence of the amine-functionalized particles did not affect the cell viability or the culture growth rate. Finally, amine-functionalized particles were successfully labeled with covalently linked fluorescing molecules.

  1. PEGylation of Phytantriol-Based Lyotropic Liquid Crystalline Particles-The Effect of Lipid Composition, PEG Chain Length, and Temperature on the Internal Nanostructure

    DEFF Research Database (Denmark)

    Nilsson, Christa; Ostergaard, Jesper; Larsen, Susan Weng

    2014-01-01

    on phytantriol (PHYT) were investigated by means of synchrotron small-angle X-ray scattering and Transmission Electron Cryo-Microscopy. The results suggest that the used lipopolymers are incorporated into the water-PHYT interfacial area and induce a significant effect on the internal nanostructures...... injectable long-circulating drug nanocarriers based on cubosomes and hexosomes by shielding and coating the dispersed particles enveloping well-defined internal nonlamellar liquid crystalline nanostructures with hydrophilic PEG segments. The present study attempts to shed light on the possible PEGylation...... of these lipidic nonlamellar liquid crystalline particles by using DSPE-mPEGs with three different block lengths of the hydrophilic PEG segment. The effects of lipid composition, PEG chain length, and temperature on the morphology and internal nanostructure of these self-assembled lipidic aqueous dispersions based...

  2. Use of dynamic membranes for the preparation of vitamin E-loaded lipid particles: An alternative to prevent fouling observed in classical cross-flow emulsification

    NARCIS (Netherlands)

    Lauoini, A.; Charcosset, C.; Fessi, H.; Schroën, C.G.P.H.

    2014-01-01

    Solid lipid particles (SLP) were introduced at the beginning of the 1990s as an alternative to encapsulation systems such as emulsions and liposomes used in cosmetic and pharmaceutical preparations. The present paper investigated for the first time the preparation of SLP based on premix emulsificati

  3. Nanoscale science and engineering forum (706c) design of solid lipid particles with iron oxide quantum dots for the delivery of therapeutic agents

    Science.gov (United States)

    Solid lipid particles provide a method to encapsulate and control the release of drugs in vivo but lack the imaging capability provided by CdS quantum dots. This shortcoming was addressed by combining these two technologies into a model system that uses iron oxide as a non-toxic imaging component in...

  4. SEM/EDS of Submicron and Coarse PM Using Modified Passive Aerosol Sampler Substrates

    Science.gov (United States)

    Wagner, J.; Wang, Z.; Willis, B.; Casuccio, G.

    2008-12-01

    Deployment of multiple UNC Passive Aerosol Samplers is an inexpensive and unobtrusive technique for assessing airborne particulate matter (PM) exposure and spatial variability. Computer-controlled SEM/EDS (Scanning Electron Microscopy / Energy-Dispersive X-ray Spectroscopy) is used to measure the deposited particle mass and chemistry. A deposition velocity model is used to obtain ambient PM and elemental size distributions. Previous results have correlated well with active sampler results in environments dominated by coarse mineral dusts. To accurately measure submicron and carbonaceous aerosols, an improved collection substrate is needed. Previous studies used a double-sided carbon adhesive tab, which was ideal for coarse PM but under-detected submicron PM. One promising alternative is polycarbonate (PC) filter substrates. Another is transmission electron microscope (TEM) grids with formvar films mounted over holes drilled in the samplers. Preliminary tests of PC filters and TEM grid substrates, including tests in areas with smoke aerosols, exhibited substantial submicron aerosol and differing elemental size distributions. Detailed qualitative and quantitative evidence shows that the PC filters retained coarse PM well and yielded improved submicron PM imaging. TEM grids yield the best imaging and chemistry of submicron carbonaceous PM, but potentially the poorest retention of coarse PM. PM and elemental size distributions are presented for collocated passive samplers using the three substrate types, in both indoor and outdoor environments. Several methods are proposed to further optimize passive sampling of both submicron and coarse PM. Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.

  5. Synthetic virus-like particles target dendritic cell lipid rafts for rapid endocytosis primarily but not exclusively by macropinocytosis.

    Directory of Open Access Journals (Sweden)

    Rajni Sharma

    Full Text Available DC employ several endocytic routes for processing antigens, driving forward adaptive immunity. Recent advances in synthetic biology have created small (20-30 nm virus-like particles based on lipopeptides containing a virus-derived coiled coil sequence coupled to synthetic B- and T-cell epitope mimetics. These self-assembling SVLP efficiently induce adaptive immunity without requirement for adjuvant. We hypothesized that the characteristics of DC interaction with SVLP would elaborate on the roles of cell membrane and intracellular compartments in the handling of a virus-like entity known for its efficacy as a vaccine. DC rapidly bind SVLP within min, co-localised with CTB and CD9, but not caveolin-1. In contrast, internalisation is a relatively slow process, delivering SVLP into the cell periphery where they are maintained for a number of hrs in association with microtubules. Although there is early association with clathrin, this is no longer seen after 10 min. Association with EEA-1(+ early endosomes is also early, but proteolytic processing appears slow, the SVLP-vesicles remaining peripheral. Association with transferrin occurs rarely, and only in the periphery, possibly signifying translocation of some SVLP for delivery to B-lymphocytes. Most SVLP co-localise with high molecular weight dextran. Uptake of both is impaired with mature DC, but there remains a residual uptake of SVLP. These results imply that DC use multiple endocytic routes for SVLP uptake, dominated by caveolin-independent, lipid raft-mediated macropinocytosis. With most SVLP-containing vesicles being retained in the periphery, not always interacting with early endosomes, this relates to slow proteolytic degradation and antigen retention by DC. The present characterization allows for a definition of how DC handle virus-like particles showing efficacious immunogenicity, elements valuable for novel vaccine design in the future.

  6. HIV-1 Vpu's lipid raft association is dispensable for counteraction of the particle release restriction imposed by CD317/Tetherin

    Energy Technology Data Exchange (ETDEWEB)

    Fritz, Joeelle V., E-mail: joelle.fritz@med.uni-heidelberg.de; Tibroni, Nadine, E-mail: nadine.tibroni@med.uni-heidelberg.de; Keppler, Oliver T., E-mail: oliver.keppler@med.uni-heidelberg.de; Fackler, Oliver T., E-mail: oliver.fackler@med.uni-heidelberg.de

    2012-03-01

    HIV-1 Vpu antagonizes the block to particle release mediated by CD317 (BST-2/HM1.24/Tetherin) via incompletely understood mechanisms. Vpu and CD317 partially reside in cholesterol-rich lipid rafts where HIV-1 budding preferentially occurs. Here we find that lipid raft association of ectopically expressed or endogenous CD317 was unaltered upon co-expression with Vpu or following HIV-1 infection. Similarly, Vpu's lipid raft association remained unchanged upon expression of CD317. We identify amino acids V25 and Y29 of Vpu as crucial for microdomain partitioning and single substitution of these amino acids resulted in Vpu variants with markedly reduced or undetectable lipid raft association. These mutations did not affect Vpu's subcellular distribution and binding capacity to CD317, nor its ability to downmodulate cell surface CD317 and promote HIV-1 release from CD317-positive cells. We conclude that (i) lipid raft incorporation is dispensable for Vpu-mediated CD317 antagonism and (ii) Vpu does not antagonize CD317 by extraction from lipid rafts.

  7. Submicron Surface-Patterned Fibers and Textiles

    Science.gov (United States)

    2016-11-04

    Submitted to 1 DOI: 10.1002/adma.((please add manuscript number)) Article type : Communication Submicron surface-patterned fibers and...we investigate three specific types of physical forming techniques: milling, laser cutting, and molding (Figure S1). Each method has its unique...semi-crystalline Submitted to 4 polymers, such as polyvinylidene fluoride (PVDF). Conventional molding methods for plastics limit the feature

  8. Filling schemes at submicron scale: Development of submicron sized plasmonic colour filters

    Science.gov (United States)

    Rajasekharan, Ranjith; Balaur, Eugeniu; Minovich, Alexander; Collins, Sean; James, Timothy D.; Djalalian-Assl, Amir; Ganesan, Kumaravelu; Tomljenovic-Hanic, Snjezana; Kandasamy, Sasikaran; Skafidas, Efstratios; Neshev, Dragomir N.; Mulvaney, Paul; Roberts, Ann; Prawer, Steven

    2014-09-01

    The pixel size imposes a fundamental limit on the amount of information that can be displayed or recorded on a sensor. Thus, there is strong motivation to reduce the pixel size down to the nanometre scale. Nanometre colour pixels cannot be fabricated by simply downscaling current pixels due to colour cross talk and diffraction caused by dyes or pigments used as colour filters. Colour filters based on plasmonic effects can overcome these difficulties. Although different plasmonic colour filters have been demonstrated at the micron scale, there have been no attempts so far to reduce the filter size to the submicron scale. Here, we present for the first time a submicron plasmonic colour filter design together with a new challenge - pixel boundary errors at the submicron scale. We present simple but powerful filling schemes to produce submicron colour filters, which are free from pixel boundary errors and colour cross- talk, are polarization independent and angle insensitive, and based on LCD compatible aluminium technology. These results lay the basis for the development of submicron pixels in displays, RGB-spatial light modulators, liquid crystal over silicon, Google glasses and pico-projectors.

  9. On the diurnal cycle of urban aerosols, black carbon and the occurrence of new particle formation events in springtime São Paulo, Brazil

    National Research Council Canada - National Science Library

    J. Backman; L. V. Rizzo; J. Hakala; T. Nieminen; H. E. Manninen; F. Morais; P. P. Aalto; E. Siivola; S. Carbone; R. Hillamo; P. Artaxo; A. Virkkula; T. Petäjä; M. Kulmala

    2012-01-01

    .... The study describes the diurnal behaviour of the submicron aerosol and relies on total particle number concentration, particle number size distribution, light scattering and light absorption measurements...

  10. Hyphenating size-exclusion chromatography with electrospray mass spectrometry; using on-line liquid-liquid extraction to study the lipid composition of lipoprotein particles.

    Science.gov (United States)

    Osei, Michael; Griffin, Julian L; Koulman, Albert

    2015-11-15

    Lipoproteins belong to the most commonly measured clinical biochemical parameters. Lipidomics is an orthogonal approach and aims to profile the individual lipid molecules that jointly form the lipoprotein particles. However, in the first step of the extraction of lipid molecules from serum, an organic solvent is used leading to dissociation of the lipoproteins. Thus far it has been impossible to combine lipidomics and lipoprotein analysis in one analytical system. Human plasma was diluted in phosphate-buffered saline (PBS) and injected onto a Superose 6 PC 3.2 column with PBS as a mobile phase to separate lipoproteins. The eluent was led to a Syrris FLLEX module, which also received CHCl3 /MeOH (3:1). The two phases were mixed and subsequently separated using a Teflon membrane in an especially designed pressurized flow chamber. The organic phase was led to a standard electrospray source of an Orbitrap mass spectrometer. Size-exclusion chromatography (SEC) has been commonly applied to separate lipoproteins and is considered a practical alternative to ultracentrifugation. Through the on-line liquid-liquid extraction method it becomes possible to obtained detailed mass spectra of lipids across different lipoprotein fractions. The extracted ion chromatograms of specific lipid signals showed their distribution against the size of lipoprotein particles. The application of on-line liquid-liquid extraction allows for the continuous electrospray-based mass spectral analysis of SEC eluent, providing the detailed lipid composition of lipoprotein particles separated by size. This approach provides new possibilities for the study of the biochemistry of lipoproteins. © 2015 The Authors. Rapid Communications in Mass Spectrometry Published by John Wiley & Sons Ltd.

  11. Effect of Variable Solvents on Particle Size of Geranium Oil-Loaded Solid Lipid Nanoparticle (Ge-SLN) For Mosquito Repellent Applications

    Science.gov (United States)

    Asnawi, Syalwati; Aziz, Azila A.; Aziz, Ramlan A.

    2009-06-01

    A new delivery system for insect repellent is proposed by the incorporation of geranium oil into solid lipid nanoparticle (SLN). A variety of solvents which act as co-surfactants, were introduced to increase the particle size of GE-SLN. Ethanol, which has a high boiling point and a long chain alcohol produced larger particle than dichloromethane. The structure of SLN was not stable when methanol and acetone were used as co-solvents. Concentration of solvents can also influence the size of SLN. In vitro release experiments showed that SLN was able to reduce the rapid evaporation of geranium oil.

  12. Lipid-soluble smoke particles upregulate vascular smooth muscle ETB receptors via activation of mitogen-activating protein kinases and NF-kappaB pathways

    DEFF Research Database (Denmark)

    Xu, C.B.; Zheng, J.P.; Zhang, W.

    2008-01-01

    Cigarette smoke is a strong risk factor for cardiovascular disease. However, the underlying molecular mechanisms that lead to cigarette smoke-associated cardiovascular disease remain elusive. With functional and molecular methods, we demonstrate for the first time that lipid-soluble cigarette smoke...... particles (dimethylsulfoxide-soluble cigarette smoke particles; DSP) increased the expression of endothelin type B (ET(B)) receptors in arterial smooth muscle cells. The increased ET(B) receptors in arterial smooth muscle cells was documented as enhanced contractility (sensitive myograph technique...

  13. PEGylation of phytantriol-based lyotropic liquid crystalline particles--the effect of lipid composition, PEG chain length, and temperature on the internal nanostructure.

    Science.gov (United States)

    Nilsson, Christa; Østergaard, Jesper; Larsen, Susan Weng; Larsen, Claus; Urtti, Arto; Yaghmur, Anan

    2014-06-10

    Poly(ethylene glycol)-grafted 1,2-distearoyl-sn-glycero-3-phosphoethanolamines (DSPE-mPEGs) are a family of amphiphilic lipopolymers attractive in formulating injectable long-circulating nanoparticulate drug formulations. In addition to long circulating liposomes, there is an interest in developing injectable long-circulating drug nanocarriers based on cubosomes and hexosomes by shielding and coating the dispersed particles enveloping well-defined internal nonlamellar liquid crystalline nanostructures with hydrophilic PEG segments. The present study attempts to shed light on the possible PEGylation of these lipidic nonlamellar liquid crystalline particles by using DSPE-mPEGs with three different block lengths of the hydrophilic PEG segment. The effects of lipid composition, PEG chain length, and temperature on the morphology and internal nanostructure of these self-assembled lipidic aqueous dispersions based on phytantriol (PHYT) were investigated by means of synchrotron small-angle X-ray scattering and Transmission Electron Cryo-Microscopy. The results suggest that the used lipopolymers are incorporated into the water-PHYT interfacial area and induce a significant effect on the internal nanostructures of the dispersed submicrometer-sized particles. The hydrophilic domains of the internal liquid crystalline nanostructures of these aqueous dispersions are functionalized, i.e., the hydrophilic nanochannels of the internal cubic Pn3m and Im3m phases are significantly enlarged in the presence of relatively small amounts of the used DSPE-mPEGs. It is evident that the partial replacement of PHYT by these PEGylated lipids could be an attractive approach for the surface modification of cubosomal and hexosomal particles. These PEGylated nanocarriers are particularly attractive in designing injectable cubosomal and hexosomal nanocarriers for loading drugs and/or imaging probes.

  14. Phase transformation and intense 2.7 μm emission from Er3+ doped YF3/YOF submicron-crystals.

    Science.gov (United States)

    Chai, Guanqi; Dong, Guoping; Qiu, Jianrong; Zhang, Qinyuan; Yang, Zhongmin

    2013-01-01

    Yttrium fluoride YF3:Er(3+) and yttrium oxyfluoride YOF:Er(3+) submicron-crystals with mid-infrared fluorescent emissions were synthesized for the first time. The rhombohedral phase YOF submicron-crystals were synthesized by the crystalline phase transformation from pure orthorhombic YF3 submicron-crystals, which were prepared by co-precipitation method. The composition and morphology were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM), which showed that submicron-crystals were quasi-spherical with the particle size of ~400 nm. A novel formation mechanism of YOF submicron-crystals was proposed. Photoluminescence (PL) spectra indicated the 2.7 μm emission of Er(3+) has remarkably enhanced with the increase of Er(3+) doping concentration, and a novel dynamic circulatory energy transfer mechanism was proposed. Fourier transform infrared spectra (FTIR) were used to demonstrate the change of hydroxyl content. These oxyfluoride submicron-crystals provide a new material for nano/submicron-crystals-glass composites, and open a brand new field for the realization of mid-infrared micro/nano-lasers.

  15. Fog-Influenced Submicron Aerosol Number Size Distributions

    Science.gov (United States)

    Zikova, N.; Zdimal, V.

    2013-12-01

    The aim of this work is to evaluate the influence of fog on aerosol particle number size distributions (PNSD) in submicron range. Thus, five-year continuous time series of the SMPS (Scanning Mobility Particle Sizer) data giving information on PNSD in five minute time step were compared with detailed meteorological records from the professional meteorological station Kosetice in the Czech Republic. The comparison included total number concentration and PNSD in size ranges between 10 and 800 nm. The meteorological records consist from the exact times of starts and ends of individual meteorological phenomena (with one minute precision). The records longer than 90 minutes were considered, and corresponding SMPS spectra were evaluated. Evaluation of total number distributions showed considerably lower concentration during fog periods compared to the period when no meteorological phenomenon was recorded. It was even lower than average concentration during presence of hydrometeors (not only fog, but rain, drizzle, snow etc. as well). Typical PNSD computed from all the data recorded in the five years is in Figure 1. Not only median and 1st and 3rd quartiles are depicted, but also 5th and 95th percentiles are plotted, to see the variability of the concentrations in individual size bins. The most prevailing feature is the accumulation mode, which seems to be least influenced by the fog presence. On the contrary, the smallest aerosol particles (diameter under 40 nm) are effectively removed, as well as the largest particles (diameter over 500 nm). Acknowledgements: This work was supported by the projects GAUK 62213 and SVV-2013-267308. Figure 1. 5th, 25th, 50th, 75th and 95th percentile of aerosol particle number size distributions recorded during fog events.

  16. Submicron FETs Using Molecular Beam Epitaxy.

    Science.gov (United States)

    1979-08-01

    C NISMIMOTO N0001-77-C-0655 UNCLASSIFIED NLIiiII/mlum.. varian SUBMICRON FETs USING MOLECULAR BEAM EPITAXY 00 ANNUAL REPORT NO. 2 (August 1978...Ohmic Contacts to Highly Doped n-type GaAs Layers Grown by Molecular Beam Epitaxy (MBE) for Field-Effect Trans- istors," J. Appl. Phys. 50, 951 (1979...36 ’A, References (Cont.) 8. D. M. Collins, "The Use of SnTe as the Source of Donor Impurities in GaAs Grown by Molecular Beam Epitaxy ," Appl. Phys

  17. [Nasal submicron emulsion of Scutellariae Radix extract preparation technology research based on phase transfer of solute technology].

    Science.gov (United States)

    Shi, Ya-jun; Shi, Jun-hui; Chen, Shi-bin; Yang, Ming

    2015-07-01

    Based on the demand of nasal drug delivery high drug loadings, using the unique phase transfer of solute, integrating the phospholipid complex preparation and submicron emulsion molding process of Scutellariae Radix extract, the study obtained the preparation of the high drug loadings submicron emulsion of Scutellariae Radix extract. In the study of drug solution dispersion method, the uniformity of drug dispersed as the evaluation index, the traditional mixing method, grinding, homogenate and solute phase transfer technology were investigated, and the solute phase transfer technology was adopted in the last. With the adoption of new technology, the drug loading capacity reached 1.33% (phospholipid complex was 4%). The drug loading capacity was improved significantly. The transfer of solute method and timing were studied as follows,join the oil phase when the volume of phospholipid complex anhydrous ethanol solution remaining 30%, the solute phase transfer was completed with the continued recycling of anhydrous ethanol. After drug dissolved away to oil phase, the preparation technology of colostrum was determined with the evaluation index of emulsion droplet form. The particle size of submicron emulsion, PDI and stability parameters were used as evaluation index, orthogonal methodology were adopted to optimize the submicron emulsion ingredient and main influential factors of high pressure homogenization technology. The optimized preparation technology of Scutellariae Radix extract nasal submicron emulsion is practical and stable.

  18. Novel action of apolipoprotein E (ApoE: ApoE isoform specifically inhibits lipid-particle-mediated cholesterol release from neurons

    Directory of Open Access Journals (Sweden)

    Fujita Shinobu C

    2007-05-01

    Full Text Available Abstract Background Since the majority of apolipoprotein E (apoE existing in the cerebrospinal fluid is associated with high-density lipoprotein (HDL, one should focus on the role of the apoE-HDL complex rather than on that of free apoE in cholesterol metabolism in the central nervous system. However, the apoE-isoform-specific effect of apoE-HDL on cholesterol transport remains unclarified. Results Here we show that apoE3-HDL induced a marked cholesterol release from neurons, while apoE4-HDL induced little. To elucidate the mechanism underlying this phenomenon, we used a complex of lipid emulsion (EM with recombinant apoE3 or apoE4 (apoE-EM at various apoE concentrations. When a small number of apoE molecules were associated with EM, apoE3- and apoE4-EM, induced a marked cholesterol release to a level similar to that induced by EM alone. However, when apoE at given concentrations was incubated with EM, apoE3-EM induced a marked cholesterol release, while apoE4-EM induced little. Under these conditions, a greater number of apoE4 molecules were associated with EM than apoE3 molecules. When an increasing number of apoE molecules were associated with EM, both apoE3-EM and apoE4-EM induced little cholesterol release. Preincubation with β-mercaptoethanol increased the number of apoE3 molecules associated with EM similar to that of apoE4 molecules, indicating that the presence (apoE3 or absence (apoE4 of intermolecular disulfide bond formation is responsible for the association of a greater number of apoE4 molecules to EM than apoE3 molecules. Conclusion These results suggest that although apoE and a lipid particle are lipid acceptors, when apoE and a lipid particle form a complex, apoE on the particle surface inhibits the lipid particle-mediated cholesterol release from cells in an apoE-concentration-dependent manner.

  19. Measuring the complex field scattered by single submicron particles

    Directory of Open Access Journals (Sweden)

    Marco A. C. Potenza

    2015-11-01

    Full Text Available We describe a method for simultaneous measurements of the real and imaginary parts of the field scattered by single nanoparticles illuminated by a laser beam, exploiting a self-reference interferometric scheme relying on the fundamentals of the Optical Theorem. Results obtained with calibrated spheres of different materials are compared to the expected values obtained through a simplified analytical model without any free parameters, and the method is applied to a highly polydisperse water suspension of Poly(D,L-lactide-co-glycolide nanoparticles. Advantages with respect to existing methods and possible applications are discussed.

  20. Single particle detection: Phase control in submicron Hall sensors

    Science.gov (United States)

    Di Michele, Lorenzo; Shelly, Connor; Gallop, John; Kazakova, Olga

    2010-11-01

    We present a phase-sensitive ac-dc Hall magnetometry method which allows a clear and reliable separation of real and parasitic magnetic signals of a very small magnitude. High-sensitivity semiconductor-based Hall crosses are generally accepted as a preferential solution for non-invasive detection of superparamagnetic nanobeads used in molecular biology, nanomedicine, and nanochemistry. However, detection of such small beads is often hindered by inductive pick-up and other spurious signals. The present work demonstrates an unambiguous experimental route for detection of small magnetic moments and provides a simple theoretical background for it. The reliability of the method has been tested for a variety of InSb Hall sensors in the range 600 nm-5 μm. Complete characterization of empty devices, involving Hall coefficients and noise measurements, has been performed and detection of a single FePt bead with diameter of 140 nm and magnetic moment of μ ≈108 μB has been achieved with a 600 nm-wide sensor.

  1. Measuring the complex field scattered by single submicron particles

    Energy Technology Data Exchange (ETDEWEB)

    Potenza, Marco A. C., E-mail: marco.potenza@unimi.it; Sanvito, Tiziano [Department of Physics, University of Milan, via Celoria, 16 – I-20133 Milan (Italy); CIMAINA, University of Milan, via Celoria, 16 – I-20133 Milan (Italy); EOS s.r.l., viale Ortles 22/4, I-20139 Milan (Italy); Pullia, Alberto [Department of Physics, University of Milan, via Celoria, 16 – I-20133 Milan (Italy)

    2015-11-15

    We describe a method for simultaneous measurements of the real and imaginary parts of the field scattered by single nanoparticles illuminated by a laser beam, exploiting a self-reference interferometric scheme relying on the fundamentals of the Optical Theorem. Results obtained with calibrated spheres of different materials are compared to the expected values obtained through a simplified analytical model without any free parameters, and the method is applied to a highly polydisperse water suspension of Poly(D,L-lactide-co-glycolide) nanoparticles. Advantages with respect to existing methods and possible applications are discussed.

  2. Submicron electrode gaps fabricated by gold electrodeposition at interdigitated electrodes

    NARCIS (Netherlands)

    Megen, M.J.J; Olthuis, W.; Berg, van den A.

    2014-01-01

    Electrodes with submicron gaps are desired for achieving high amplification redox cycling sensors. In this contribution we report the use of electrodeposition of gold in order to decrease the inter-electrode spacing at interdigitated electrodes. Using this method submicron spacings can be obtained w

  3. 葡聚糖双亲性衍生物修饰PLA亚微粒子的制备及其表面多重生物因子功能化%SURFACE MULTI-BIOFUNCTIONALIZATION OF PLA SUBMICRON PARTICLES COATED WITH AMPHIPHILIC DEXTRAN DERIVATES

    Institute of Scientific and Technical Information of China (English)

    顾鸣岐; 原续波; 田恩江; 盛京

    2006-01-01

    以胆固醇半琥珀酸酰氯对NaIO4氧化的醛化葡聚糖进行疏水改性,制备了醛基化双亲性葡聚糖衍生物Chol-Dex-CHO;利用醛基与己二酰肼酰腙化反应,实现葡聚糖主链的氨基化;生物素经二环已基碳二亚胺活化后与双亲性葡聚糖衍生物主链上的氨基偶联,形成生物素化(3%)双亲性葡聚糖(Chol-Dex-Biotin).将聚乳酸(PLA)与Chol-Dex-Biotin溶液共透析可形成亚微粒子,双亲性多糖可通过疏水基团锚定于PLA亚微粒子表面,透射电子显微镜与原子力显微镜测试观察到清晰的球形核壳结构,激光粒度仪测定亚微粒子粒径与粒径分布表明调节Chol-Dex-Biotin与PLA的配比可以控制亚微粒子的粒径(150~200 nm),X-射线光电子能谱证明亚微粒表面存在Chol-Dex-Biotin.在此基础上,以FITC标记的转铁蛋白(Tf-FITC)和生物素化兔IgG为模型生物功能因子,分别通过共价偶联及生物素-亲合素物理结合两种机理对葡聚糖包覆的PLA纳米微粒表面进行多重生物因子功能化修饰,得到表面Tf和IgG双重修饰的PLA亚微粒子(Tf-PLA-IgG submicron particles).亚微粒子表面Tf和兔IgG的结合分别通过荧光显微镜观测和抗IgG-辣根过氧化氢酶(IgG-HRP)显色反应验证.

  4. A novel inlet system for on-line chemical analysis of semi-volatile submicron particulate matter

    Directory of Open Access Journals (Sweden)

    P. Eichler

    2014-09-01

    Full Text Available We herein present the concept of a novel modular inlet system that allows using gas-phase analyzers for on-line chemical characterization of semi-volatile submicron particles. The "chemical analysis of aerosol on-line" (CHARON inlet consists of a gas-phase denuder for stripping off gas-phase analytes, an aerodynamic lens for particle enrichment in the sampling flow and a thermo-desorption unit for particle volatilization prior to chemical analysis. We coupled the CHARON inlet to a proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS which quantitatively detects most organic analytes and ammonia. The combined set-up measures submicron organic and ammonium nitrate/sulfate particles online. Two proof-of-principle studies were carried out for demonstrating the analytical power of the new set-up in analyzing primarily emitted and secondarily generated particles. Oxygenated organics and their partitioning between the gas and the particulate phase were observed from the reaction of limonene with ozone. Abundant quasi-molecular ions of organic particulate constituents were observed when submicron particles were sampled from diluted mainstream cigarette smoke.

  5. Particle Emissions from Domestic Gas Cookers

    DEFF Research Database (Denmark)

    Glarborg, Peter; Livbjerg, Hans; Wagner, Ayten Yilmaz

    2010-01-01

    The authors experimentally studied the formation of submicron particles from a domestic gas cooker in a compartment free from external particle sources. The effects of fuel (methane, natural gas, odorant-free natural gas), primary aeration, flow rate, and fuel sulphur content on particle emissions...... were investigated. The experiments confirmed reports from literature that blue burning flames of domestic gas cookers emit submicron particles. The particle number concentrations varied in the range 103-106 particles/cm3, depending on the fuel, flow rate, and primary air addition. The diameters...

  6. Exploring the Role of Sub-micron Sized Dust Grains in the Atmospheres of Red L0 - L6 Dwarfs

    CERN Document Server

    Hiranaka, Kay; Douglas, Stephanie T; Marley, Mark S; Baldassare, Vivienne F

    2016-01-01

    We examine the hypothesis that the red near-infrared colors of some L dwarfs could be explained by a "dust haze" of small particles in their upper atmospheres. This dust haze would exist in conjunction with the clouds found in dwarfs with more typical colors. We developed a model which uses Mie theory and the Hansen particle size distributions to reproduce the extinction due to the proposed dust haze. We apply our method to 23 young L dwarfs and 23 red field L dwarfs. We constrain the properties of the dust haze including particle size distribution and column density using Markov-Chain Monte Carlo methods. We find that sub-micron range silicate grains reproduce the observed reddening. Current brown dwarf atmosphere models include large grain (1--100~$\\mu m$) dust clouds but not submicron dust grains. Our results provide a strong proof of concept and motivate a combination of large and small dust grains in brown dwarf atmosphere models.

  7. Upregulation of contractile endothelin type B receptors by lipid-soluble cigarette smoking particles in rat cerebral arteries via activation of MAPK

    DEFF Research Database (Denmark)

    Sandhu, Hardip; Xu, Cang Bao; Edvinsson, Lars

    2010-01-01

    Cigarette smoke exposure increases the risk of stroke. However, the underlying molecular mechanisms are poorly understood. Endothelin system plays key roles in the pathogenesis of stroke. The present study was designed to examine if lipid-soluble (dimethyl sulfoxide-soluble) cigarette smoke...... or water-soluble cigarette smoke particles to the organ culture. The increased upregulation of contractile ET(B) receptors by DSP was abrogated by U0126, SP600125, actinomycin D, and cycloheximide, suggesting that the underlying molecular mechanisms involved in this process include activation of MEK...

  8. Electrodeposited submicron thermocouples with microsecond response times.

    Science.gov (United States)

    Bourg, M E; van der Veer, W E; Güell, A G; Grüell, A G; Penner, R M

    2007-10-01

    We describe a procedure for preparing submicron scale silver-nickel thermocouples (TCs) using electrochemical step edge decoration on graphite surfaces. Each fabrication operation produced ensembles of 2-20 TCs with diameters in the 1.0 microm to 500 nm range. These "sub-mum TCs" (SMTCs) produced linear voltage versus temperature output over the range from 20 to 100 degrees C characterized by a Seebeck coefficient of 20 +/- 1 microV/degrees C, equal to the 21 microV/degrees C that is theoretically expected for a junction between these two metals. The time response of SMTCs was evaluated using two different laser-heating methods and compared with the smallest mechanically robust commercially available type J TCs. Electrochemical etching of the silver wire introduced constrictions at grain boundaries that reduced the thermal mass of the junction without altering its integrity or its overall diameter, producing a decrease of the measured rise time for SMTCs up to 96%.

  9. Submicron and nano formulations of titanium dioxide and zinc oxide stimulate unique cellular toxicological responses in the green microalga Chlamydomonas reinhardtii

    Energy Technology Data Exchange (ETDEWEB)

    Gunawan, Cindy, E-mail: c.gunawan@unsw.edu.au [ARC Centre of Excellence for Functional Nanomaterials, School of Chemical Engineering, The University of New South Wales, Sydney, NSW (Australia); Sirimanoonphan, Aunchisa [ARC Centre of Excellence for Functional Nanomaterials, School of Chemical Engineering, The University of New South Wales, Sydney, NSW (Australia); Teoh, Wey Yang [Clean Energy and Nanotechnology (CLEAN) Laboratory, School of Energy and Environment, City University of Hong Kong, Kowloon, Hong Kong Special Administrative Region (Hong Kong); Marquis, Christopher P., E-mail: c.marquis@unsw.edu.au [School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW (Australia); Amal, Rose [ARC Centre of Excellence for Functional Nanomaterials, School of Chemical Engineering, The University of New South Wales, Sydney, NSW (Australia)

    2013-09-15

    Highlights: • Uptake of TiO{sub 2} solids by C. reinhardtii generates ROS as an early stress response. • Submicron and nanoTiO{sub 2} exhibit benign effect on cell proliferation. • Uptake of ZnO solids and leached zinc by C. reinhardtii inhibit the alga growth. • No cellular oxidative stress is detected with submicron and nano ZnO exposure. • The toxicity of particles is not necessarily mediated by cellular oxidative stress. -- Abstract: The work investigates the eco-cytoxicity of submicron and nano TiO{sub 2} and ZnO, arising from the unique interactions of freshwater microalga Chlamydomonas reinhardtii to soluble and undissolved components of the metal oxides. In a freshwater medium, submicron and nano TiO{sub 2} exist as suspended aggregates with no-observable leaching. Submicron and nano ZnO undergo comparable concentration-dependent fractional leaching, and exist as dissolved zinc and aggregates of undissolved ZnO. Cellular internalisation of solid TiO{sub 2} stimulates cellular ROS generation as an early stress response. The cellular redox imbalance was observed for both submicron and nano TiO{sub 2} exposure, despite exhibiting benign effects on the alga proliferation (8-day EC50 > 100 mg TiO{sub 2}/L). Parallel exposure of C. reinhardtii to submicron and nano ZnO saw cellular uptake of both the leached zinc and solid ZnO and resulting in inhibition of the alga growth (8-day EC50 ≥ 0.01 mg ZnO/L). Despite the sensitivity, no zinc-induced cellular ROS generation was detected, even at 100 mg ZnO/L exposure. Taken together, the observations confront the generally accepted paradigm of cellular oxidative stress-mediated cytotoxicity of particles. The knowledge of speciation of particles and the corresponding stimulation of unique cellular responses and cytotoxicity is vital for assessment of the environmental implications of these materials.

  10. Lipid effects on neutrophil calcium signaling induced by opsonized particles: platelet activating factor is only part of the story.

    NARCIS (Netherlands)

    Wanten, G.J.A.; Kusters, A.; Emst-de Vries, S.E. van; Tool, A.; Roos, D.; Naber, A.H.J.; Willems, P.

    2004-01-01

    BACKGROUND & METHODS: Total parenteral nutrition is frequently used in clinical practice to improve the nutritional status of patients. However, the risk for infectious complications remains a drawback in which immune-modulating effects of the lipid component may play a role. To characterize these l

  11. Airborne studies of submicron aerosol in the troposphere over West Siberia

    Energy Technology Data Exchange (ETDEWEB)

    Panchenko, M.V.; Zuev, V.E.; Belan, B.D.; Terpugova, S.A. [Institute of Atmospheric Optics, Tomsk (Russian Federation)

    1996-04-01

    Submicron fraction particles that have the longest lifespan and are included in almost all atmospheric processes are of special importance among the great variety of sizes of particles present in the atmosphere. Submicron particles mainly determine the opticle state of the atmosphere in the visible spectral range, essentially cause the absorption of infrared radiation and, since they are the products and participants in all aerosol-to-gas transformations, accumulate of a lot of various chemical compounds and transfer them to large distances. Investigation of the processes of the spatial-temporal variability of aerosol particles for different climatic zones of the earth is the experimental base for studying their effect on climatically and ecologically significant factors and estimating their unfavorable tendencies. The increasing anthropogenic loading of the earth`s atmosphere is creating an urgency for aerosol research. Regardless of how perfect the analytical and numerical methods of solving radiation problems may be, success in forecasting climatic change is mainly determined by the reliability of the experimental data on optical parameters of the atmosphere and of the description of their variability under the effect of external factors.

  12. Fluidization of nano and sub-micron powders using mechanical vibration

    Institute of Scientific and Technical Information of China (English)

    Souresh Kaliyaperumal; Shahzad Barghi; Lauren Briens; Sohrab Rohani; Jesse Zhu

    2011-01-01

    The fluidization behavior of nano and sub-micron powders belonging to group C of Geldart's classification was studied in a mechanically vibrated fluidized bed (vibro-fluidized bed) at room temperature.Pretreated air was used as the fluidizing gas whereas SiO2, Al2O3, TiO2, ZrSi, BaSO4 were solid particles.Mechanical vibration amplitudes were 0.1, 0.25, 0.35, 0.45 mm, while the frequencies were 5, 20, 30,40 Hz to investigate the effects of frequency and amplitude of mechanical vibration on minimum fluidization velocity, bed pressure drop, bed expansion, and the agglomerate size and size distribution. A novel technique was employed to determine the apparent minimum fluidization velocity from pressure drop signals. Richardson-Zaki equation was employed as nano-particles showed fluid like behavior when fluidized. The average size of agglomerates formed on top of the bed was smaller than those at the bottom.Size distribution of agglomerates on top was also more uniform compared to those near the distributor.Larger agglomerates at the bottom of the bed formed a small fraction of the bed particles. Average size of submicron agglomerates decreased with increasing the frequency of vibration, however nano particles were less sensitive to change in vibration frequency. Mechanical vibration enhanced the quality of fluidization by reducing channeling and rat-holing phenomena caused by interparticle cohesive forces.

  13. NMR-Based Lipid Profiling of High Density Lipoprotein Particles in Healthy Subjects with Low, Normal, and Elevated HDL-Cholesterol.

    Science.gov (United States)

    Kostara, Christina E; Tsimihodimos, Vasilis; Elisaf, Moses S; Bairaktari, Eleni T

    2017-04-07

    Recent studies suggest that the cholesterol content of HDL (high density lipoproteins) may provide limited information on their antiatherogenic properties and that the composition and particles' structure provide more information on their functionality. We used NMR-based (nuclear magnetic resonance-based) lipidomics to study the relationships of serum HDL-C (HDL-cholesterol) levels with the lipid composition of HDL particles in three groups of subjects selected on the basis of their HDL-C levels. Subjects with low and high HDL-C levels exhibited differences in HDL lipidome compared to those with normal HDL-C levels. In pattern recognition analysis, the discrimination power among all groups was of high significance. The low HDL-C group presented enrichment of the core in triglycerides and depletion in cholesterol esters, whereas the high HDL-C group showed a decrease in triglycerides content. Additionally, as HDL-C increases, all lipid classes are esterified with higher percentage of unsaturated than saturated fatty acids. In addition to the aforementioned differences, the surface layer is enriched in sphingomyelin and free cholesterol in the high HDL-C level group. NMR-based lipidomic analysis of HDL can be particularly useful since it provides insights into molecular features and helps in the characterization of the atheroprotective function of HDL lipoproteins and in the identification of novel biomarkers of cardiovascular risk.

  14. Lyophilized silica lipid hybrid (SLH) carriers for poorly water-soluble drugs: physicochemical and in vitro pharmaceutical investigations.

    Science.gov (United States)

    Yasmin, Rokhsana; Tan, Angel; Bremmell, Kristen E; Prestidge, Clive A

    2014-09-01

    Lyophilization was investigated to produce a powdery silica-lipid hybrid (SLH) carrier for oral delivery of poorly water-soluble drugs. The silica to lipid ratio, incorporation of cryoprotectant, and lipid loading level were investigated as performance indicators for lyophilized SLH carriers. Celecoxib, a nonsteroidal anti-inflammatory drug, was used as the model poorly soluble moiety to attain desirable physicochemical and in vitro drug solubilization properties. Scanning electron microscopy and confocal fluorescence imaging verified a nanoporous, homogenous internal matrix structures of the lyophilized SLH particles, prepared from submicron triglyceride emulsions and stabilized by porous silica nanoparticles (Aerosil 380), similar to spray-dried SLH. 20-50 wt % of silica in the formulation have shown to produce nonoily SLH agglomerates with complete lipid encapsulation. The incorporation of a cryoprotectant prevented irreversible aggregation of the silica-stabilized droplets during lyophilization, thereby readily redispersing in water to form micrometre-sized particles (drug solubilization than the pure drug under nondigesting and digesting conditions, respectively. The feasibility of lyophilization for producing nanostructured SLH formulations with desirable lipid loading and drug solubilization properties for enhanced oral delivery of poorly water-soluble therapeutics is confirmed. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

  15. Sub-micron Cu/SSZ-13: Synthesis and application as selective catalytic reduction (SCR) catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Prodinger, Sebastian; Derewinski, Miroslaw A.; Wang, Yilin; Washton, Nancy M.; Walter, Eric D.; Szanyi, János; Gao, Feng; Wang, Yong; Peden, Charles H. F.

    2017-02-01

    For the first time, sub-micron Cu/SSZ-13, obtained by modifying an existing synthesis procedure, was shown to be an effective and stable catalyst for selective catalytic reduction reactions, such as NO reduction. Characterization of the materials with X-ray diffraction, N2-physisorption and 27Al MAS NMR shows that hydrothermal aging, simulating SCR reaction conditions, is more destructive in respect to dealumination for smaller particles prior to Cu-exchange. However, the catalytic performance and hydrothermal stability for Cu/SSZ-13 is independent of the particle size. In particular, the stability of tetrahedral framework Al is improved in the sub-micron Cu/SSZ-13 catalysts of comparable Cu loading. This indicates that variations in the Al distribution for different SSZ-13 synthesis procedures have a more critical influence on stabilizing isolated Cu-ions during harsh hydrothermal aging than the particle size. This study is of high interest for applications in vehicular DeNOx technologies where high loadings of active species on wash coats can be achieved by using sub-micron Cu/SSZ-13. The authors would like to thank B. W. Arey and J. J. Ditto for performing electron microscope imaging. The authors gratefully acknowledge the US Department of Energy (DOE), Energy Efficiency and Renewable Energy, Vehicle Technologies Office for the support of this work. S. P and M. A. D also acknowledge support by the Materials Synthesis and Simulation Across Scales (MS3 Initiative) conducted under the Laboratory Directed Research & Development Program at PNNL. The research described in this paper was performed in the Environmental Molecular Sciences Laboratory (EMSL), a national scientific user facility sponsored by the DOE’s Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory (PNNL). PNNL is operated for the US DOE by Battelle.

  16. On the Acoustic Properties of Vaporized Submicron Perfluorocarbon Droplets

    NARCIS (Netherlands)

    Reznik, Nikita; Lajoinie, Guillaume; Shpak, Oleksandr; Gelderblom, Erik C.; Williams, Ross; Jong, de Nico; Versluis, Michel; Burns, Peter N.

    2014-01-01

    The acoustic characteristics of microbubbles created from vaporized submicron perfluorocarbon droplets with fluorosurfactant coating are examined. Utilizing ultra-high-speed optical imaging, the acoustic response of individual microbubbles to low-intensity diagnostic ultrasound was observed on clini

  17. Thymol-based submicron emulsions exhibit antifungal activity against Fusarium graminearum and inhibit Fusarium head blight in wheat.

    Science.gov (United States)

    Gill, T A; Li, J; Saenger, M; Scofield, S R

    2016-10-01

    Fusarium graminearum is a very destructive fungal pathogen that leads to Fusarium head blight (FHB) in wheat, a disease which costs growers millions of dollars annually both in crop losses and in remediation efforts. Current countermeasures include the deployment of wheat varieties with some resistance to FHB in conjunction with timed fungicide treatments. In this article, we introduce a fungicide based on thymol, a naturally occurring plant phenolic derived from essential oils. To overcome the hydrophobicity of thymol, the thymol active was incorporated into a low-surfactant submicron emulsion with and without a carrier oil. The minimum fungicidal concentration of F. graminearum was found to be both 0·02% for thymol emulsions with and without an oil component. Time-to-kill experiments showed that thymol emulsions were able to inactivate F. graminearum in as little as 10 s at concentrations above 0·06%. Spraying the thymol emulsions (~0·1% range) on the wheat variety Bobwhite demonstrated significant reductions in FHB infection rate (number of infected spikelets). However, with 0·5% thymol, the wheat heads exhibited premature senescence. Transmission and scanning electron micrographs suggest that the mechanism of antifungal action is membrane mediated, as conidia exposed to thymol showed complete organelle disorganization and evidence of lipid emulsification. The collective experimental data suggest that thymol emulsions may be an effective naturally derived alternative to the current thymol treatments, and chemical fungicides in ameliorating FHB. This is the first thymol-derived nanoemulsion particles resuspended into water and not DMSO, exhibiting the same antibacterial/antifungal activity as previously described thymol and thyme oil treatments. This drastically reduces the environmental footprint thymol will leave if utilized as a fungicide treatment on field crops. © 2016 The Society for Applied Microbiology.

  18. Submicron Features in Higher Manganese Silicide

    Directory of Open Access Journals (Sweden)

    Yatir Sadia

    2013-01-01

    Full Text Available The world energy crisis had increased the demand for alternative energy sources and as such is one of the topics at the forefront of research. One way for reducing energy consumption is by thermoelectricity. Thermoelectric effects enable direct conversion of thermal into electrical energy. Higher manganese silicide (HMS, MnSi1.75 is one of the promising materials for applications in the field of thermoelectricity. The abundance and low cost of the elements, combined with good thermoelectric properties and high mechanical and chemical stability at high temperatures, make it very attractive for thermoelectric applications. Recent studies have shown that Si-rich HMS has improved thermoelectric properties. The most interesting of which is the unusual reduction in thermal conductivity. In the current research, transmission (TEM and scanning (SEM electron microscopy as well as X-ray diffraction methods were applied for investigation of the govern mechanisms resulting in very low thermal conductivity values of an Si-rich HMS composition, following arc melting and hot-pressing procedures. In this paper, it is shown that there is a presence of sub-micron dislocations walls, stacking faults, and silicon and HMS precipitates inside each other apparent in the matrix, following a high temperature (0.9 Tm hot pressing for an hour. These are not just responsible for the low thermal conductivity values observed but also indicate the ability to create complicate nano-structures that will last during the production process and possibly during the application.

  19. Cell lipid metabolism modulators 2-bromopalmitate, D609, monensin, U18666A and probucol shift discoidal HDL formation to the smaller-sized particles: implications for the mechanism of HDL assembly.

    Science.gov (United States)

    Quach, Duyen; Vitali, Cecilia; La, Fiona M; Xiao, Angel X; Millar, John S; Tang, Chongren; Rader, Daniel J; Phillips, Michael C; Lyssenko, Nicholas N

    2016-12-01

    ATP-binding cassette transporter A1 (ABCA1) mediates formation of disc-shaped high-density lipoprotein (HDL) from cell lipid and lipid-free apolipoprotein A-I (apo A-I). Discoidal HDL particles are heterogeneous in physicochemical characteristics for reasons that are understood incompletely. Discoidal lipoprotein particles similar in characteristics and heterogeneity to cell-formed discoidal HDL can be reconstituted from purified lipids and apo A-I by cell-free, physicochemical methods. The heterogeneity of reconstituted HDL (rHDL) is sensitive to the lipid composition of the starting lipid/apo A-I mixture. To determine whether the heterogeneity of cell-formed HDL is similarly sensitive to changes in cell lipids, we investigated four compounds that have well-established effects on cell lipid metabolism and ABCA1-mediated cell cholesterol efflux. 2-Bromopalmitate, D609, monensin and U18666A decreased formation of the larger-sized, but dramatically increased formation of the smaller-sized HDL. 2-Bromopalmitate did not appear to affect ABCA1 activity, subcellular localization or oligomerization, but induced dissolution of the cholesterol-phospholipid complexes in the plasma membrane. Arachidonic and linoleic acids shifted HDL formation to the smaller-sized species. Tangier disease mutations and inhibitors of ABCA1 activity wheat germ agglutinin and AG 490 reduced formation of both larger-sized and smaller-sized HDL. The effect of probucol was similar to the effect of 2-bromopalmitate. Taking rHDL formation as a paradigm, we propose that ABCA1 mutations and activity inhibitors reduce the amount of cell lipid available for HDL formation, and the compounds in the 2-bromopalmitate group and the polyunsaturated fatty acids change cell lipid composition from one that favors formation of the larger-sized HDL particles to one that favors formation of the smaller-sized species. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Intense photooxidative degradation of planktonic and bacterial lipids in sinking particles collected with sediment traps across the Canadian Beaufort Shelf (Arctic Ocean

    Directory of Open Access Journals (Sweden)

    J.-F. Rontani

    2012-06-01

    Full Text Available The lipid content of seven samples of sinking particles collected with sediment traps moored at ~100 m depth in summer and fall across the Canadian Beaufort Shelf (Arctic Ocean was investigated. Our main goal was to quantify and characterize the biotic and abiotic degradation processes that acted on sinking material during these periods. Diatoms, which dominated the phytoplanktonic assemblage in every trap sample, appeared to be remarkably sensitive to Type II (i.e. involving singlet oxygen photodegradation processes in summer, but seemed to be relatively unaffected by biotic degradation at the same time. Hence, the relative recalcitrance of phytodetritus towards biodegradation processes during the Arctic midnight sun period was attributed to the strong photodegradation state of heterotrophic bacteria, which likely resulted from the efficient transfer of singlet oxygen from photodegraded phytoplanktonic cells to attached bacteria. In addition, the detection in trap samples of photoproducts specific to wax ester components found in herbivorous copepods demonstrated that zooplanktonic faecal material exported out of the euphotic zone in summer were as well affected by Type II photodegradation processes. By contrast, sinking particles collected during the autumn were not influenced by any light-driven stress. Further chemical analyses showed that photodegraded sinking particles contained an important amount of intact hydroperoxides, which could then induce a strong oxidative stress in underlying sediments.

  1. The effect of fish oil enriched margarine on plasma lipids, low density lipoprotein particle composition, size and susceptibility to oxidation

    DEFF Research Database (Denmark)

    Nielsen, Nina Skall; Marckmann, Peter; Høy, Carl-Erik;

    1998-01-01

    We investigated the effect of incorporating n-3 polyunsaturated fatty acids (PUFAs) into the diet on the lipid-class composition of LDLs, their size, and their susceptibility to oxidation. Forty-seven healthy volunteers incorporated 30 g sunflower-oil (SO) margarine/d into their habitual diet...... during a 3-wk run-in period and then used either SQ or a fish-oil-enriched sunflower oil (FO) margarine for the following 4 wk. Plasma concentrations of total cholesterol, triacylglycerols, HDL cholesterol, LDL cholesterol, and apolipoproteins A-I and B did not differ significantly between the groups...

  2. Vectors and submicron precision: redundancy and 3D stacking in silicon pixel detectors

    CERN Document Server

    Heijne, E H M; Wong, W; Idarraga, J; Visser, J; Jakubek, J; Leroy, C; Turecek, D; Visschers, J; Pospisil, S; Ballabriga, R; Vykydal, Z; Vermeulen, J; Plackett, R; Heijne, E H M; Llopart, X; Boltje, D; Campbell, M

    2010-01-01

    Measurements are shown of GeV pions and muons in two 300 mu m thick, Si Medipix pixel detector assemblies that are stacked on top of each other, with a 25 mu m thick brass foil in between. In such a radiation imaging semiconductor matrix with a large number of pixels along the particle trail, one can determine local space vectors for the particle trajectory instead of points. This improves pattern recognition and track reconstruction, especially in a crowded environment. Stacking of sensor planes is essential for resolving directional ambiguities. Signal charge sharing can be employed for measuring positions with submicron precision. In the measurements one notices accompanying `delta' electrons that emerge outside the particle trail, far beyond the boundaries of the 55 mu m pixel cells. The frequency of such corrupted position measurements is similar to one per 2.5mm of traversed Si.

  3. Analysis of submicron-sized niflumic acid crystals prepared by electrospray crystallization.

    Science.gov (United States)

    Ambrus, Rita; Radacsi, Norbert; Szunyogh, Tímea; van der Heijden, Antoine E D M; Ter Horst, Joop H; Szabó-Révész, Piroska

    2013-03-25

    Interest in submicron-sized drug particles has emerged from both laboratory and industrial perspectives in the last decade. Production of crystals in the nano size scale offers a novel way to particles for drug formulation solving formulation problems of drugs with low solubility in class II of the Biopharmaceutical Classification System. In this work niflumic acid nanoparticles with a size range of 200-800nm were produced by the novel crystallization method, electrospray crystallization. Their properties were compared to those from evaporative and anti-solvent crystallizations, using the same organic solvent, acetone. There is a remarkable difference in the product crystal size depending on the applied methods. The size and morphology were analyzed by scanning electron microscopy and laser diffraction. The structure of the samples was investigated using differential scanning calorimetry, Fourier-transformed infrared spectroscopy and X-ray powder diffraction. The particles produced using electrospray crystallization process were probably changing from amorphous to crystalline state after the procedure.

  4. Cellular uptake of beta-carotene from protein stabilized solid lipid nano-particles prepared by homogenization-evaporation method

    Science.gov (United States)

    Using a homogenization-evaporation method, beta-carotene (BC) loaded nano-particles were prepared with different ratios of food-grade sodium caseinate (SC), whey protein isolate (WPI), or soy protein isolate (SPI) to BC and evaluated for their physiochemical stability, in vitro cytotoxicity, and cel...

  5. Comparative physical-chemical characterization of encapsulated lipid-based isotretinoin products assessed by particle size distribution and thermal behavior analyses

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, Carla Aiolfi, E-mail: carlaaiolfi@usp.br [Department of Pharmacy, Faculty of Pharmaceutical Sciences, University of Sao Paulo, Sao Paulo, SP 05508-000 (Brazil); Menaa, Farid [Department of Dermatology, School of Medicine Wuerzburg, Wuerzburg 97080 (Germany); Fluorotronics, Inc., 1425 Russ Bvld, San Diego Technology Incubator, San Diego, CA 92101 (United States); Menaa, Bouzid, E-mail: bouzid.menaa@gmail.com [Fluorotronics, Inc., 1425 Russ Bvld, San Diego Technology Incubator, San Diego, CA 92101 (United States); Quenca-Guillen, Joyce S. [Department of Pharmacy, Faculty of Pharmaceutical Sciences, University of Sao Paulo, Sao Paulo, SP 05508-000 (Brazil); Matos, Jivaldo do Rosario [Department of Fundamental Chemistry, Institute of Chemistry, University of Sao Paulo, Sao Paulo, SP 05508-000 (Brazil); Mercuri, Lucildes Pita [Department of Exact and Earth Sciences, Federal University of Sao Paulo, Diadema, SP 09972-270 (Brazil); Braz, Andre Borges [Department of Engineering of Mines and Oil, Polytechnical School, University of Sao Paulo, SP 05508-900 (Brazil); Rossetti, Fabia Cristina [Department of Pharmaceutical Sciences, Faculty of Pharmaceutical Sciences of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, SP 14015-120 (Brazil); Kedor-Hackmann, Erika Rosa Maria; Santoro, Maria Ines Rocha Miritello [Department of Pharmacy, Faculty of Pharmaceutical Sciences, University of Sao Paulo, Sao Paulo, SP 05508-000 (Brazil)

    2010-06-10

    Isotretinoin is the drug of choice for the management of severe recalcitrant nodular acne. Nevertheless, some of its physical-chemical properties are still poorly known. Hence, the aim of our study consisted to comparatively evaluate the particle size distribution (PSD) and characterize the thermal behavior of the three encapsulated isotretinoin products in oil suspension (one reference and two generics) commercialized in Brazil. Here, we show that the PSD, estimated by laser diffraction and by polarized light microscopy, differed between the generics and the reference product. However, the thermal behavior of the three products, determined by thermogravimetry (TGA), differential thermal (DTA) analyses and differential scanning calorimetry (DSC), displayed no significant changes and were more thermostable than the isotretinoin standard used as internal control. Thus, our study suggests that PSD analyses in isotretinoin lipid-based formulations should be routinely performed in order to improve their quality and bioavailability.

  6. Artifacts for Calibration of Submicron Width Measurements

    Science.gov (United States)

    Grunthaner, Frank; Grunthaner, Paula; Bryson, Charles, III

    2003-01-01

    Artifacts that are fabricated with the help of molecular-beam epitaxy (MBE) are undergoing development for use as dimensional calibration standards with submicron widths. Such standards are needed for calibrating instruments (principally, scanning electron microscopes and scanning probe microscopes) for measuring the widths of features in advanced integrated circuits. Dimensional calibration standards fabricated by an older process that involves lithography and etching of trenches in (110) surfaces of single-crystal silicon are generally reproducible to within dimensional tolerances of about 15 nm. It is anticipated that when the artifacts of the present type are fully developed, their critical dimensions will be reproducible to within 1 nm. These artifacts are expected to find increasing use in the semiconductor-device and integrated- circuit industries as the width tolerances on semiconductor devices shrink to a few nanometers during the next few years. Unlike in the older process, one does not rely on lithography and etching to define the critical dimensions. Instead, one relies on the inherent smoothness and flatness of MBE layers deposited under controlled conditions and defines the critical dimensions as the thicknesses of such layers. An artifact of the present type is fabricated in two stages (see figure): In the first stage, a multilayer epitaxial wafer is grown on a very flat substrate. In the second stage, the wafer is cleaved to expose the layers, then the exposed layers are differentially etched (taking advantage of large differences between the etch rates of the different epitaxial layer materials). The resulting structure includes narrow and well-defined trenches and a shelf with thicknesses determined by the thicknesses of the epitaxial layers from which they were etched. Eventually, it should be possible to add a third fabrication stage in which durable, electronically inert artifacts could be replicated in diamondlike carbon from a master made by

  7. X, Ku-band microwave-absorption properties of polyarylene ether nitriles terminated with phthalonitrile/Fe{sub 3}O{sub 4} hybrid submicron spheres

    Energy Technology Data Exchange (ETDEWEB)

    Tong, Lifen, E-mail: 361626614@qq.com; Pu, Zejun; Huang, Xu; Liu, Xiaobo, E-mail: liuxb@uestc.edu.cn

    2014-05-01

    Highlights: • PEN-t-Ph/Fe{sub 3}O{sub 4} hybrid spheres were prepared via one-step solvothermal method. • Polymer compatibility is introduced into inorganic submicron spheres successfully. • PEN-t-Ph/Fe{sub 3}O{sub 4} hybrid submicron spheres possessed good ferrimagnetism. • Control the microwave absorption band of PEN-t-Ph/Fe{sub 3}O{sub 4} hybrid submicron spheres. - Abstract: A novel series of PEN-t-Ph/Fe{sub 3}O{sub 4} hybrid submicron spheres with different additions of PEN-t-Ph have been prepared successfully via solvothermal method, and their structures and morphologies were characterized by X-ray powder diffraction (XRD), energy dispersive spectrometer (EDS), Fourier transform infrared spectrophotometer (FTIR), and scanning electron microscopy (SEM). The results revealed that the crystallinity, dispersity, and size of hybrid submicron spheres can be controlled by altering the addition content of PEN-t-Ph. Magnetization measurement showed that the PEN-t-Ph/Fe{sub 3}O{sub 4} hybrid submicron spheres possessed good ferrimagnetism. The electromagnetic measurement indicated that the resonance peaks of complex permittivity, complex permeability, dielectric loss, and magnetic loss were shifted to the higher frequency as the addition of PEN-t-Ph increased. Moreover, the microwave absorption band was also shifted to higher frequency as the addition of PEN-t-Ph increased. Through this method, the polymer compatibility can be introduced into inorganic submicron spheres, which could provide the inorganic particles with more applications.

  8. Sub-micron alignment for nuclear emulsion plates using low energy electrons caused by radioactive isotopes

    Science.gov (United States)

    Miyamoto, S.; Ariga, A.; Fukuda, T.; Kazuyama, M.; Komatsu, M.; Nakano, T.; Niwa, K.; Sato, O.; Takahashi, S.

    2007-06-01

    Nuclear emulsion plates are employed in three-dimensional charged particle detectors that have sub-micron position resolution over 1 m2 with no dead space and no dead time. These detectors are suitable for the study of short-lived particle decays, and direct detection of neutrino interactions of all flavors. Typically emulsion plates are used in a stacked structure. Precise alignment between plates is required for physics analysis. The most accurate alignment method is to use tracks passing through the emulsion plates. The accuracy is about 0.2 μm. However, in an experiment with low track density alignment accuracy decreases to 20 μm because of plate distortion and it becomes more difficult to perform the analysis. This paper describes a new alignment method between emulsion plates by using trajectories of low energy electrons originating from environmental radioactive isotopes. As a trial emulsion plates were exposed to β-rays and γ-rays from K40. The trajectories which passed through emulsion layers were detected by a fully automated emulsion readout system. Using this method, the alignment between emulsion plates is demonstrated to be sub-micron. This method can be applied to many nuclear emulsion experiments. For example, the location of neutrino interaction vertices in the OPERA experiment can benefit from this new technique.

  9. Infiltration techniques for suppressing grain growth during the densification of submicron and nanophase alumina composites

    Science.gov (United States)

    Vernon, Deborah Marshall

    Grain growth control during the final stages of densification is an issue with extreme technological significance. In the last decade, nanophase ceramic starting powders have become commercially available, and in order to take full advantage of the unique properties nanophase ceramics potentially offer, grain growth control during processing of these materials must be addressed. In this research study the author addresses the topic of suppression of grain growth in submicron and nanophase alumina using novel processing techniques. The approach used to decrease grain boundary motion during processing involves the addition of an intermediate step between initial powder pressing and sintering. During the intermediate step either solute amounts of an infiltrant are incorporated along grain boundary junctions through a vapor-phase technique or, second phase inclusions are formed within the pore structure of the ceramic porous compacts via a liquid-phase technique. Using the vapor-phase technique, silicon nitride was introduced into porous submicron and nanophase alumina compacts. It was determined that silicon nitride in amounts below the solubility limit is an effective grain growth inhibitor. In the submicron pellets studies, three regions of grain growth were observed: abnormal, suppressed, and normal. Using a mathematical model developed for simulating the vapor infiltration process, a range of silicon concentrations (70 to 50 ppm) was determined to correspond to the suppressed grain growth region. In the nanophase silicon nitride infiltrated pellets, suppression of grain growth was observed throughout the infiltrated specimen, however the suppression effects were not great enough to retain the nanosized nature of the alumina grains. Using the liquid-phase technique, zirconia particles were formed within the pore structure of submicron and nanophase alumina compacts. A comparison between suppression effects in compacts created by liquid-phase and by powder

  10. Investigating the correlation between in vivo absorption and in vitro release of fenofibrate from lipid matrix particles in biorelevant medium

    DEFF Research Database (Denmark)

    Borkar, Nrupa Nitin; Xia, Dengning; Holm, René

    2014-01-01

    , suggesting that nano-sized LMP were digested to a larger extent due to greater specific surface area. The 100 nm LMP showed faster initial digestion followed by 400 nm LMP and microparticles. The area under the plasma concentration-time curve (AUC) following oral administration of 100 nm LMP...... (%) of fenofibrate partitioning into the aqueous phase during in vitro lipolysis and the AUC of plasma concentration-time curve of fenofibric acid was in the order of 100 nm LMP>microparticles>control. In summary, the present study demonstrated the particle size dependence of bioavailability of fenofibrate loaded...

  11. Tetanus toxoid-loaded cationic non-aggregated nanostructured lipid particles triggered strong humoral and cellular immune responses.

    Science.gov (United States)

    Kaur, Amandeep; Jyoti, Kiran; Rai, Shweta; Sidhu, Rupinder; Pandey, Ravi Shankar; Jain, Upendra Kumar; Katyal, Anju; Madan, Jitender

    2016-05-01

    In the present investigation, non-aggregated cationic and unmodified nanoparticles (TT-C-NLPs4 and TT-NLPs1) were prepared of about 49.2 ± 6.8-nm and 40.8 ± 8.3-nm, respectively. In addition, spherical shape, crystalline architecture and cationic charge were also noticed. Furthermore, integrity and conformational stability of TT were maintained in both TT-C-NLPs4 and TT-NLPs1, as evidenced by symmetrical position of bands and superimposed spectra, respectively in SDS-PAGE and circular dichroism. Cellular uptake in RAW264.7 cells indicating the concentration-dependent internalisation of nanoparticles. Qualitatively, CLSM exhibited enhanced cellular uptake of non-aggregated TT-C-NLPs4 owing to interaction with negatively charged plasma membrane and clevaloe mediated/independent endocytosis. In last, in vivo immunisation with non-aggregated TT-C-NLPs4 elicited strong humoral (anti-TT IgG) and cellular (IFN-γ) immune responses at day 42, as compared to non-aggregated TT-NLPs1 and TT-Alum following booster immunisation at day 14 and 28. Thus, non-aggregated cationic lipid nanoparticles may be a potent immune-adjuvant for parenteral delivery of weak antigens.

  12. NATO Advanced Study Institute on Physics of Submicron Semiconductor Devices

    CERN Document Server

    Ferry, David; Jacoboni, C

    1988-01-01

    The papers contained in the volume represent lectures delivered as a 1983 NATO ASI, held at Urbino, Italy. The lecture series was designed to identify the key submicron and ultrasubmicron device physics, transport, materials and contact issues. Nonequilibrium transport, quantum transport, interfacial and size constraints issues were also highlighted. The ASI was supported by NATO and the European Research Office. H. L. Grubin D. K. Ferry C. Jacoboni v CONTENTS MODELLING OF SUB-MICRON DEVICES.................. .......... 1 E. Constant BOLTZMANN TRANSPORT EQUATION... ... ...... .................... 33 K. Hess TRANSPORT AND MATERIAL CONSIDERATIONS FOR SUBMICRON DEVICES. . .. . . . . .. . . . .. . .. . .... ... .. . . . .. . . . .. . . . . . . . . . . 45 H. L. Grubin EPITAXIAL GROWTH FOR SUB MICRON STRUCTURES.................. 179 C. E. C. Wood INSULATOR/SEMICONDUCTOR INTERFACES.......................... 195 C. W. Wilms en THEORY OF THE ELECTRONIC STRUCTURE OF SEMICONDUCTOR SURFACES AND INTERFACES...................

  13. Thin film coated submicron gratings: theory, design, fabrication and application

    Energy Technology Data Exchange (ETDEWEB)

    Heine, C.

    1996-12-31

    The realization of new applications of submicron grating structures requires efficient theoretical methods and elaborate fabrication techniques. In this work rigorous diffraction theory for one-dimensional gratings has been investigated and optimization techniques, based on methods used in thin film optics, have been developed. Submicron gratings embossed in polycarbonate have been fabricated and characterized. This includes transmission measurements which are in good agreement with theoretical calculations. Designs for a wide range of optical filters, which lead to improved optical and mechanical properties, are presented. This has been demonstrated for broadband antireflection structures for solar energy applications, based on MgF{sub 2}-coated gratings. (author) figs., tabs., refs.

  14. A supercritical fluid-based coating technology. 3: preparation and characterization of bovine serum albumin particles coated with lipids.

    Science.gov (United States)

    Ribeiro Dos Santos, I; Richard, J; Thies, C; Pech, B; Benoit, J-P

    2003-01-01

    Solvent-free microparticles, loaded with bovine serum albumin as a model protein, were produced using a novel supercritical (SC) fluid-based coating technology. Coating material consists either of trimyristin (Dynasan 114) or of Gelucire 50-02. Microparticles obtained were characterized as regards their morphology, protein content and in vitro release profile. A discontinuous coating made of micro-needles of trimyristin led to an initial burst release of approximately 70% in 30 min. However, a prolonged release of the BSA could be achieved in a phosphate buffer solution at 37 degrees C over a 24 h period from particles coated with Gelucire 50-02. Furthermore, it was shown that BSA does not undergo any degradation after SC CO(2) treatment under the conditions used in the coating process.

  15. Bloch-Wave Engineered Submicron Diameter Micropillars with Quality Factors Exceeding 10,000

    DEFF Research Database (Denmark)

    Hofling, S.; Lermer, M.; Gregersen, Niels;

    2011-01-01

    Adiabatic design submicron diameter quantum-dot micropillars have been designed and implemented for cavity quantum electrodynamics experiments. Ultra-high experimental quality factors (>10,000) are obtained for submicron diameters and strong light-matter interaction is observed.......Adiabatic design submicron diameter quantum-dot micropillars have been designed and implemented for cavity quantum electrodynamics experiments. Ultra-high experimental quality factors (>10,000) are obtained for submicron diameters and strong light-matter interaction is observed....

  16. Fabrication of pullulan and pectin submicron fibers by electrospinning

    Science.gov (United States)

    Pullulan (PUL), a food grade polysaccharide, was fabricated into fibrous mats from fibers of submicron size by electrospinning. The effects of inorganic salts and polyanions present in the electrospinning solution on the properties of the resultant fibers was investigated. The inclusion of exogenous...

  17. Analog Circuits in Ultra-Deep-Submicron CMOS

    NARCIS (Netherlands)

    Annema, Anne-Johan; Nauta, Bram; Langevelde, van Ronald; Tuinhout, Hans

    2005-01-01

    Modern and future ultra-deep-submicron (UDSM) technologies introduce several new problems in analog design. Nonlinear output conductance in combination with reduced voltage gain pose limits in linearity of (feedback) circuits. Gate-leakage mismatch exceeds conventional matching tolerances. Increasin

  18. Spinning of a submicron sphere by Airy beams.

    Science.gov (United States)

    Kim, Kyoung-Youm; Kim, Saehwa

    2016-01-01

    We show that by employing two incoherent counter-propagating Airy beams, we can manipulate a submicron sphere to spin around a transverse axis. We can control not only the spinning speed, but also the direction of the spinning axis by changing the polarization directions of Airy beams.

  19. Pharmacokinetic performance of the nitrendipine intravenous submicron emulsion in rats

    Directory of Open Access Journals (Sweden)

    Jibin Guan

    2014-12-01

    Full Text Available To compare pharmacokinetic behaviors of nitrendipine submicron emulsion with nitrendipine solution following intravenous administration in rats. The plasma concentrations were analyzed by ultra-performance liquid chromatography coupled with tandem mass spectrometry detection (UPLC–MS/MS through a new validated method. The pharmacokinetic parameters of the nitrendipine submicron emulsion and nitrendipine solution were as follows: AUC0–t 900.76 ± 186.59 versus 687.08 ± 66.24 ng h/ml, Cmax 854.54 ± 159.48 versus 610.59 ± 235.99 ng/ml, t1/2 2.37 ± 1.99 versus 2.80 ± 2.69 h. The relative bioavailability of nitrendipine submicron emulsion to nitrendipine solution was 131.4 ± 11.3%. The developed methods could meet the requirements of bioanalysis. Compared to the solution injection, intravenous submicron emulsion presents higher systematic exposure which can help to improve the therapeutic efficacy.

  20. Edge effects and submicron tracks in magnetic tape recording

    NARCIS (Netherlands)

    Hozoi, Adrian

    2005-01-01

    The scope of the work presented in this thesis was to investigate the recording phenomena at very high track density and understand the requirements for reaching submicron tracks in magnetic tape. A broad study of edge effects is presented with a focus on side writing and erasing, which are critical

  1. Reversal mechanism of submicron patterned CoNi/Pt multilayers

    NARCIS (Netherlands)

    Haast, M.A.M.; Schuurhuis, J.R.; Abelmann, L.; Lodder, J.C.; Popma, Th.J.A.

    1998-01-01

    With laser interference lithography Co50Ni50/Pt multilayers with perpendicular magnetic anisotropy have been patterned into regular matrices of submicron sized dots. Their magnetic properties have been studied with Vibrating Sample Magnetometry. Compared to continuous multilayers (Hc=15 kA/m) the co

  2. High Proportions of Sub-micron Particulate Matter in Icelandic Dust Storms in 2015

    Science.gov (United States)

    Dagsson Waldhauserova, Pavla; Arnalds, Olafur; Olafsson, Haraldur; Magnusdottir, Agnes

    2017-04-01

    Iceland is extremely active dust region and desert areas of over 44,000 km2 acknowledge Iceland as the largest Arctic and European desert. Frequent dust events, up to 135 dust days annually, transport dust particles far distances towards the Arctic and Europe. Satellite MODIS pictures have revealed dust plumes exceeding 1,000 km. The annual dust deposition was calculated as 40.1 million tons yr-1. Two dust storms were measured in transverse horizontal profile about 90 km far from different dust sources in southwestern Iceland in the summer of 2015. Aerosol monitor DustTrak DRX 8533EP was used to measure PM mass concentrations corresponding to PM1, PM2.5, PM4, PM10 and the total PM15 at several places within the dust plume. Images from camera network operated by the Icelandic Road and Coastal Administration were used to estimate the visibility and spatial extent of measured dust events. A numerical simulation of surface winds was carried out with the numerical model HIRLAM with horizontal resolution of 5 km and used to calculate the total dust flux from the sources. The in situ measurements inside the dust plumes showed that aeolian dust can be very fine. The study highlights that suspended volcanic dust in Iceland causes air pollution with extremely high PM1 concentrations comparable to the polluted urban stations in Europe or Asia rather than reported dust event observations from around the world. The PM1/PM2.5 ratios are generally low during dust storms outside of Iceland, much lower than > 0.9 and PM1/PM10 ratios of 0.34-0.63 found in our study. It shows that Icelandic volcanic dust consists of higher proportion of submicron particles compared to crustal dust. The submicron particles are predicted to travel long distances. Moreover, such submicron particles pose considerable health risk because of high potential for entering the lungs. Icelandic volcanic glass has often fine pipe-vesicular structures known from asbestos and high content of heavy metals. Previous

  3. Labeling the oily core of nanocapsules and lipid-core nanocapsules with a triglyceride conjugated to a fluorescent dye as a strategy to particle tracking in biological studies.

    Science.gov (United States)

    Fiel, Luana Almeida; Contri, Renata Vidor; Bica, Juliane Freitas; Figueiró, Fabrício; Battastini, Ana Maria Oliveira; Guterres, Sílvia Stanisçuaski; Pohlmann, Adriana Raffin

    2014-01-01

    The synthesis of novel fluorescent materials represents a very important step to obtain labeled nanoformulations in order to evaluate their biological behavior. The strategy of conjugating a fluorescent dye with triacylglycerol allows that either particles differing regarding supramolecular structure, i.e., nanoemulsions, nanocapsules, lipid-core nanocapsules, or surface charge, i.e., cationic nanocapsules and anionic nanocapsules, can be tracked using the same labeled material. In this way, a rhodamine B-conjugated triglyceride was obtained to prepare fluorescent polymeric nanocapsules. Different formulations were obtained, nanocapsules (NC) or lipid-core nanocapsules (LNC), using the labeled oil and Eudragit RS100, Eudragit S100, or poly(caprolactone) (PCL), respectively. The rhodamine B was coupled with the ricinolein by activating the carboxylic function using a carbodiimide derivative. Thin layer chromatography, proton nuclear magnetic resonance ((1)H-NMR), Fourier transform infrared spectroscopy (FTIR), UV-vis, and fluorescence spectroscopy were used to identify the new product. Fluorescent nanocapsule aqueous suspensions were prepared by the solvent displacement method. Their pH values were 4.6 (NC-RS100), 3.5 (NC-S100), and 5.0 (LNC-PCL). The volume-weighted mean diameter (D 4.3) and polydispersity values were 150 nm and 1.05 (NC-RS100), 350 nm and 2.28 (NC-S100), and 270 nm and 1.67 (LNC-PCL). The mean diameters determined by photon correlation spectroscopy (PCS) (z-average) were around 200 nm. The zeta potential values were +5.85 mV (NC-RS100), -21.12 mV (NC-S100), and -19.25 mV (LNC-PCL). The wavelengths of maximum fluorescence emission were 567 nm (NC-RS100 and LNC-PCL) and 574 nm (NC-S100). Fluorescence microscopy was used to evaluate the cell uptake (human macrophage cell line) of the fluorescent nanocapsules in order to show the applicability of the approach. When the cells were treated with the fluorescent nanocapsules, red emission was

  4. Ubiquity of organic nitrates from nighttime chemistry in the European submicron aerosol

    Science.gov (United States)

    Kiendler-Scharr, A.; Mensah, A. A.; Friese, E.; Topping, D.; Nemitz, E.; Prevot, A. S. H.; ńijälä, M.; Allan, J.; Canonaco, F.; Canagaratna, M.; Carbone, S.; Crippa, M.; Dall Osto, M.; Day, D. A.; De Carlo, P.; Di Marco, C. F.; Elbern, H.; Eriksson, A.; Freney, E.; Hao, L.; Herrmann, H.; Hildebrandt, L.; Hillamo, R.; Jimenez, J. L.; Laaksonen, A.; McFiggans, G.; Mohr, C.; O'Dowd, C.; Otjes, R.; Ovadnevaite, J.; Pandis, S. N.; Poulain, L.; Schlag, P.; Sellegri, K.; Swietlicki, E.; Tiitta, P.; Vermeulen, A.; Wahner, A.; Worsnop, D.; Wu, H.-C.

    2016-07-01

    In the atmosphere nighttime removal of volatile organic compounds is initiated to a large extent by reaction with the nitrate radical (NO3) forming organic nitrates which partition between gas and particulate phase. Here we show based on particle phase measurements performed at a suburban site in the Netherlands that organic nitrates contribute substantially to particulate nitrate and organic mass. Comparisons with a chemistry transport model indicate that most of the measured particulate organic nitrates are formed by NO3 oxidation. Using aerosol composition data from three intensive observation periods at numerous measurement sites across Europe, we conclude that organic nitrates are a considerable fraction of fine particulate matter (PM1) at the continental scale. Organic nitrates represent 34% to 44% of measured submicron aerosol nitrate and are found at all urban and rural sites, implying a substantial potential of PM reduction by NOx emission control.

  5. Stability of lipid excipients in solid lipid nanoparticles.

    Science.gov (United States)

    Radomska-Soukharev, Anna

    2007-07-10

    The paper is devoted to the investigation of chemical stability of lipids used as excipients in the production of Solid Lipid Nanoparticles (SLN). Different lipids and amounts of surfactants were considered. Most of the formulations were produced using identical binary surfactant mixtures and concentrations to analyze the effect of the chemical nature of the lipids on their stability in SLN. In some formulations, surfactants were exchanged or their concentration was increased to assess the contribution of surfactants on stability of lipids particles. Solid Lipid Nanoparticles were characterized by photon correlation spectroscopy, laser diffractometry, zeta potential determination and differential scanning calorimetry. Potential effects of lipid crystallinity and modifications were assessed. A gas chromatography (GC) analysis in combination with a method for lipid extraction from aqueous SLN dispersions was used to investigate the chemical stability of the lipid excipients forming the particle matrix. All formulations were produced by the hot homogenization technique. The production process of SLN itself did not affect the chemical stability of lipid excipient forming the particle matrix. The formulations where lipids consisted of trigylicerides showed a negligible decomposition of the structure during incubation at 25 degrees C. Dynasan 118 showed the highest chemical stability (loss<4%) within two years.

  6. Laser processing of silicon at submicron scale using photochromic films

    Energy Technology Data Exchange (ETDEWEB)

    Chen Qiying; Nikumb, Suwas

    2004-05-31

    Laser fabrication at submicron scale is experimentally demonstrated with the nonlinear optical switching effect of photochromism. The effect, which is a result of change in the optical properties of the photochromic material between the open-ring and closed-ring isomers during the photoisomerization, effectively reduces the laser beam size. The ultrafast response of the molecular photocyclization and cycloreversion reactions at a time scale of a few picoseconds ensures the instantaneous realization of the effect. Utilizing a photochromic film of cis-1,2-dicyano-1,2-bis(2,4,5-trimethyl-3-thienyl) ethane as the mask layer, laser processing of a silicon wafer demonstrated submicron scale feature size with improved surface quality as compared to the smallest features achievable using direct laser ablation without the photochromic film.

  7. Submicron CMOS technologies for high energy physics and space applications

    CERN Document Server

    Anelli, G; Faccio, F; Heijne, Erik H M; Jarron, Pierre; Kloukinas, Kostas C; Marchioro, A; Moreira, P; Snoeys, W

    2001-01-01

    The radiation environment present in some of today's High-Energy Physics (HEP) experiments and in space has a detrimental influence on the integrated circuits working in these environments. Special technologies, called radiation hardened, have been used in the past to prevent the radiation-induced degradation. In the last decades, the market of these special technologies has undergone a considerable shrinkage, rendering them less reliably available and far more expensive than today's mainstream technologies. An alternative approach is to use a deep submicron CMOS technology. The most sensitive part to radiation effects in a MOS transistor is the gate oxide. One way to reduce the effects of ionizing radiation in the gate oxide is to reduce its thickness, which is a natural trend in modern technologies. Submicron CMOS technologies seem therefore a good candidate for implementing radiation-hardened integrated circuits using a commercial, inexpensive technology. Nevertheless, a certain number of radiation-induced...

  8. Lipid Profile

    Science.gov (United States)

    ... AACC products and services. Advertising & Sponsorship: Policy | Opportunities Lipid Profile Share this page: Was this page helpful? Also ... as: Lipid Panel; Coronary Risk Panel Formal name: Lipid Profile Related tests: Cholesterol ; HDL Cholesterol ; LDL Cholesterol ; Triglycerides ; ...

  9. In vivo activity of miR-34a mimics delivered by stable nucleic acid lipid particles (SNALPs against multiple myeloma.

    Directory of Open Access Journals (Sweden)

    Maria Teresa Di Martino

    Full Text Available Multiple myeloma (MM is a disease with an adverse outcome and new therapeutic strategies are urgently awaited. A rising body of evidence supports the notion that microRNAs (miRNAs, master regulators of eukaryotic gene expression, may exert anti-MM activity. Here, we evaluated the activity of synthetic miR-34a in MM cells. We found that transfection of miR-34a mimics in MM cells induces a significant change of gene expression with relevant effects on multiple signal transduction pathways. We detected early inactivation of pro-survival and proliferative kinases Erk-2 and Akt followed at later time points by caspase-6 and -3 activation and apoptosis induction. To improve the in vivo delivery, we encapsulated miR-34a mimics in stable nucleic acid lipid particles (SNALPs. We found that SNALPs miR-34a were highly efficient in vitro in inhibiting growth of MM cells. Then, we investigated the activity of the SNALPs miR-34a against MM xenografts in SCID mice. We observed significant tumor growth inhibition (p<0.05 which translated in mice survival benefits (p=0.0047. Analysis of miR-34a and NOTCH1 expression in tumor retrieved from animal demonstrated efficient delivery and gene modulation induced by SNALPs miR-34a in the absence of systemic toxicity. We here therefore provide evidence that SNALPs miR-34a may represent a promising tool for miRNA-therapeutics in MM.

  10. Investigation of the cutaneous penetration behavior of dexamethasone loaded to nano-sized lipid particles by EPR spectroscopy, and confocal Raman and laser scanning microscopy.

    Science.gov (United States)

    Lohan, Silke B; Saeidpour, Siavash; Solik, Agnieszka; Schanzer, Sabine; Richter, Heike; Dong, Pin; Darvin, Maxim E; Bodmeier, Roland; Patzelt, Alexa; Zoubari, Gaith; Unbehauen, Michael; Haag, Rainer; Lademann, Jürgen; Teutloff, Christian; Bittl, Robert; Meinke, Martina C

    2017-07-01

    An improvement of the penetration efficiency combined with the controlled release of actives in the skin can facilitate the medical treatment of skin diseases immensely. Dexamethasone (Dx), a synthetic glucocorticoid, is frequently used for the treatment of inflammatory skin diseases. To investigate the penetration of nano-sized lipid particles (NLP) loaded with Dx in comparison to a commercially available base cream, different techniques were applied. Electron paramagnetic resonance (EPR) spectroscopy was used to monitor the penetration of Dx, which was covalently labeled with the spin probe 3-(Carboxy)-2,2,5,5-tetramethyl-1-pyrrolidinyloxy (PCA). The penetration into hair follicles was studied using confocal laser scanning microscopy (CLSM) with curcumin-loaded NLP. The penetration of the vehicle was followed by confocal Raman microscopy (CRM). Penetration studies using excised porcine skin revealed a more than twofold higher penetration efficiency for DxPCA into the stratum corneum (SC) after 24h incubation compared to 4h incubation when loaded to the NLP, whereas when applied in the base cream, almost no further penetration was observed beyond 4h. The distribution of DxPCA within the SC was investigated by consecutive tape stripping. The release of DxPCA from the base cream after 24h in deeper SC layers and the viable epidermis was shown by EPR. For NLP, no release from the carrier was observed, although DxPCA was detectable in the skin after the complete SC was removed. This phenomenon can be explained by the penetration of the NLP into the hair follicles. However, penetration profiles measured by CRM indicate that NLP did not penetrate as deeply into the SC as the base cream formulation. In conclusion, NLP can improve the accumulation of Dx in the skin and provide a reservoir within the SC and in the follicular infundibula. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Effects of butter naturally enriched with conjugated linoleic acid and vaccenic acid on blood lipids and LDL particle size in growing pigs

    Directory of Open Access Journals (Sweden)

    Haug Anna

    2008-08-01

    Full Text Available Abstract Background Cow milk is a natural source of the cis 9, trans 11 isomer of conjugated linoleic acid (c9,t11-CLA and trans vaccenic acid (VA. These fatty acids may be considered as functional foods, and the concentration in milk can be increased by e.g. sunflower oil supplementation to the dairy cow feed. The objective of this study was to compare the effects of regular butter with a special butter naturally enriched in c9,t11-CLA and VA on plasma lipids in female growing pigs. The experimental period lasted for three weeks and the two diets provided daily either 5.0 g c9,t11-CLA plus 15.1 g VA or 1.3 g c9,t11-CLA plus 3.6 g VA. Results The serum concentrations of c9,t11-CLA, VA and alpha-linolenic acid were increased and myristic (14:0 and palmitic acid (16:0 were reduced in the pigs fed the CLA+VA-rich butter-diet compared to regular butter, but no differences in plasma concentrations of triacylglycerol, cholesterol, HDL-cholesterol, LDL-cholesterol, LDL particle size distribution or total cholesterol/HDL cholesterol were observed among the two dietary treatment groups. Conclusion Growing pigs fed diets containing butter naturally enriched in about 20 g c9,t11-CLA plus VA daily for three weeks, had increased serum concentrations of alpha-linolenic acid and decreased myristic and palmitic acid compared to pigs fed regular butter, implying a potential benefit of the CLA+VA butter on serum fatty acid composition. Butter enriched in CLA+VA does not appear to have significant effect on the plasma lipoprotein profile in pigs.

  12. Submicron Resolution Spectral-Domain Optical Coherence Tomography

    KAUST Repository

    Alarousu, Erkki

    2013-11-14

    Apparatuses and systems for submicron resolution spectral-domain optical coherence tomography (OCT) are disclosed. The system may use white light sources having wavelengths within 400-1000 nanometers, and achieve resolution below 1 .mu.m. The apparatus is aggregated into a unitary piece, and a user can connect the apparatus to a user provided controller and/or light source. The light source may be a supercontinuum source.

  13. Fabrication of submicron proteinaceous structures by direct laser writing

    Energy Technology Data Exchange (ETDEWEB)

    Serien, Daniela [Center for International Research on Integrative Biomedical Systems, Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, 153-8505 Tokyo (Japan); Takeuchi, Shoji, E-mail: takeuchi@iis.u-tokyo.ac.jp [Center for International Research on Integrative Biomedical Systems, Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, 153-8505 Tokyo (Japan); ERATO Takeuchi Biohybrid Innovation Project, Japan Science and Technology Agency, 4-6-1 Komaba, Meguro-ku, 153-8505 Tokyo (Japan)

    2015-07-06

    In this paper, we provide a characterization of truly free-standing proteinaceous structures with submicron feature sizes depending on the fabrication conditions by model-based analysis. Protein cross-linking of bovine serum albumin is performed by direct laser writing and two-photon excitation of flavin adenine dinucleotide. We analyze the obtainable fabrication resolution and required threshold energy for polymerization. The applied polymerization model allows prediction of fabrication conditions and resulting fabrication size, alleviating the application of proteinaceous structure fabrication.

  14. Scanning SQUID susceptometers with sub-micron spatial resolution

    Energy Technology Data Exchange (ETDEWEB)

    Kirtley, John R., E-mail: jkirtley@stanford.edu; Rosenberg, Aaron J.; Palmstrom, Johanna C.; Holland, Connor M.; Moler, Kathryn A. [Department of Applied Physics, Stanford University, Stanford, California 94305-4045 (United States); Paulius, Lisa [Department of Physics, Western Michigan University, Kalamazoo, Michigan 49008-5252 (United States); Spanton, Eric M. [Department of Physics, Stanford University, Stanford, California 94305-4045 (United States); Schiessl, Daniel [Attocube Systems AG, Königinstraße 11A, 80539 Munich (Germany); Jermain, Colin L.; Gibbons, Jonathan [Department of Physics, Cornell University, Cornell, Ithaca, New York 14853 (United States); Fung, Y.-K.K.; Gibson, Gerald W. [IBM Research Division, T. J. Watson Research Center, Yorktown Heights, New York 10598 (United States); Huber, Martin E. [Department of Physics, University of Colorado Denver, Denver, Colorado 80217-3364 (United States); Ralph, Daniel C. [Department of Physics, Cornell University, Cornell, Ithaca, New York 14853 (United States); Kavli Institute at Cornell, Ithaca, New York 14853 (United States); Ketchen, Mark B. [OcteVue, Hadley, Massachusetts 01035 (United States)

    2016-09-15

    Superconducting QUantum Interference Device (SQUID) microscopy has excellent magnetic field sensitivity, but suffers from modest spatial resolution when compared with other scanning probes. This spatial resolution is determined by both the size of the field sensitive area and the spacing between this area and the sample surface. In this paper we describe scanning SQUID susceptometers that achieve sub-micron spatial resolution while retaining a white noise floor flux sensitivity of ≈2μΦ{sub 0}/Hz{sup 1/2}. This high spatial resolution is accomplished by deep sub-micron feature sizes, well shielded pickup loops fabricated using a planarized process, and a deep etch step that minimizes the spacing between the sample surface and the SQUID pickup loop. We describe the design, modeling, fabrication, and testing of these sensors. Although sub-micron spatial resolution has been achieved previously in scanning SQUID sensors, our sensors not only achieve high spatial resolution but also have integrated modulation coils for flux feedback, integrated field coils for susceptibility measurements, and batch processing. They are therefore a generally applicable tool for imaging sample magnetization, currents, and susceptibilities with higher spatial resolution than previous susceptometers.

  15. Anthropogenic influences on the physical state of submicron particulate matter over a tropical forest

    Science.gov (United States)

    Bateman, Adam P.; Gong, Zhaoheng; Harder, Tristan H.; de Sá, Suzane S.; Wang, Bingbing; Castillo, Paulo; China, Swarup; Liu, Yingjun; O'Brien, Rachel E.; Palm, Brett B.; Shiu, Hung-Wei; Cirino, Glauber G.; Thalman, Ryan; Adachi, Kouji; Lizabeth Alexander, M.; Artaxo, Paulo; Bertram, Allan K.; Buseck, Peter R.; Gilles, Mary K.; Jimenez, Jose L.; Laskin, Alexander; Manzi, Antonio O.; Sedlacek, Arthur; Souza, Rodrigo A. F.; Wang, Jian; Zaveri, Rahul; Martin, Scot T.

    2017-02-01

    The occurrence of nonliquid and liquid physical states of submicron atmospheric particulate matter (PM) downwind of an urban region in central Amazonia was investigated. Measurements were conducted during two intensive operating periods (IOP1 and IOP2) that took place during the wet and dry seasons of the GoAmazon2014/5 campaign. Air masses representing variable influences of background conditions, urban pollution, and regional- and continental-scale biomass burning passed over the research site. As the air masses varied, particle rebound fraction, an indicator of physical state, was measured in real time at ground level using an impactor apparatus. Micrographs collected by transmission electron microscopy confirmed that liquid particles adhered, while nonliquid particles rebounded. Relative humidity (RH) was scanned to collect rebound curves. When the apparatus RH matched ambient RH, 95 % of the particles adhered as a campaign average. Secondary organic material, produced for the most part by the oxidation of volatile organic compounds emitted from the forest, produces liquid PM over this tropical forest. During periods of anthropogenic influence, by comparison, the rebound fraction dropped to as low as 60 % at 95 % RH. Analyses of the mass spectra of the atmospheric PM by positive-matrix factorization (PMF) and of concentrations of carbon monoxide, total particle number, and oxides of nitrogen were used to identify time periods affected by anthropogenic influences, including both urban pollution and biomass burning. The occurrence of nonliquid PM at high RH correlated with these indicators of anthropogenic influence. A linear model having as output the rebound fraction and as input the PMF factor loadings explained up to 70 % of the variance in the observed rebound fractions. Anthropogenic influences can contribute to the presence of nonliquid PM in the atmospheric particle population through the combined effects of molecular species that increase viscosity when

  16. Anthropogenic influences on the physical state of submicron particulate matter over a tropical forest

    Energy Technology Data Exchange (ETDEWEB)

    Bateman, Adam P.; Gong, Zhaoheng; Harder, Tristan H.; de Sá, Suzane S.; Wang, Bingbing; Castillo, Paulo; China, Swarup; Liu, Yingjun; O& amp; apos; Brien, Rachel E.; Palm, Brett B.; Shiu, Hung-Wei; Cirino, Glauber G.; Thalman, Ryan; Adachi, Kouji; Alexander, M. Lizabeth; Artaxo, Paulo; Bertram, Allan K.; Buseck, Peter R.; Gilles, Mary K.; Jimenez, Jose L.; Laskin, Alexander; Manzi, Antonio O.; Sedlacek, Arthur; Souza, Rodrigo A. F.; Wang, Jian; Zaveri, Rahul; Martin, Scot T.

    2017-02-06

    The occurrence of nonliquid and liquid physical states of submicron atmospheric particulate matter (PM) downwind of an urban region in central Amazonia was investigated. Measurements were conducted during two intensive operating periods (IOP1 and IOP2) that took place during the wet and dry seasons of the GoAmazon2014/5 campaign. Air masses representing variable influences of background conditions, urban pollution, and regional- and continental-scale biomass burning passed over the research site. As the air masses varied, particle rebound fraction, an indicator of physical state, was measured in real time at ground level using an impactor apparatus. Micrographs collected by transmission electron microscopy confirmed that liquid particles adhered, while nonliquid particles rebounded. Relative humidity (RH) was scanned to collect rebound curves. When the apparatus RH matched ambient RH, 95 % of the particles adhered as a campaign average. Secondary organic material, produced for the most part by the oxidation of volatile organic compounds emitted from the forest, produces liquid PM over this tropical forest. During periods of anthropogenic influence, by comparison, the rebound fraction dropped to as low as 60 % at 95 % RH. Analyses of the mass spectra of the atmospheric PM by positive-matrix factorization (PMF) and of concentrations of carbon monoxide, total particle number, and oxides of nitrogen were used to identify time periods affected by anthropogenic influences, including both urban pollution and biomass burning. The occurrence of nonliquid PM at high RH correlated with these indicators of anthropogenic influence. A linear model having as output the rebound fraction and as input the PMF factor loadings explained up to 70 % of the variance in the observed rebound fractions. Anthropogenic influences can contribute to the presence of nonliquid PM in the atmospheric particle population through the combined effects of molecular species that increase viscosity

  17. Inhalable nanostructured lipid particles of 9-bromo-noscapine, a tubulin-binding cytotoxic agent: in vitro and in vivo studies.

    Science.gov (United States)

    Jyoti, Kiran; Kaur, Karanvir; Pandey, Ravi Shankar; Jain, Upendra Kumar; Chandra, Ramesh; Madan, Jitender

    2015-05-01

    9-Bromo-noscapine (9-Br-Nos) alters tubulin polymerization in non-small cell lung cancer cells differently from noscapine. However, clinical applications of 9-Br-Nos are limited owing to poor aqueous solubility and high lipophilicity that eventually lead to suboptimal therapeutic efficacy at the site of action. Hence, 9-Br-Nos loaded nanostructured lipid particles (9-Br-Nos-NLPs) were prepared by nanoemulsion method to reduce the particle size below 100 nm. To impart the inhalable and rapid release (RR) attributes, 9-Br-Nos-NLPs were treated with spray dried lactose and effervescent excipients to generate, 9-Br-Nos-RR-NLPs. The mean particle and aerodynamic size of 9-Br-Nos-NLPs were measured to be 13.4±3.2 nm and 2.3±1.5 μm, significantly (P<0.05) lower than 19.4±6.1 nm and 3.1±1.8 μm of 9-Br-Nos-RR-NLPs. In addition, zeta-potential of 9-Br-Nos-NLPs was examined to be -9.54±0.16 mV, significantly (P<0.05) lower than -7.23±0.10 mV of 9-Br-Nos-RR-NLPs. Hence, both formulations were found to be optimum for pulmonary delivery through inhalation route of administration. Next, 9-Br-Nos-RR-NLPs exhibited enhanced cytotoxicity, apoptosis and cellular uptake in A549, lung cancer cells, as compared to 9-Br-Nos-NLPs and 9-Br-Nos suspension. This may be attributed to enhanced drug delivery and internalization character of 9-Br-Nos-RR-NLPs by energy-dependent endocytosis and passive diffusion mechanism. Pharmacokinetic and distribution analysis demonstrated the superiority of 9-Br-Nos-RR-NLPs that exhibited ∼1.12 and ∼1.75-folds enhancement in half-life of the drug as compared to 9-Br-Nos-NLPs and 9-Br-Nos powder following inhalation route. Continuation to this, 9-Br-Nos-RR-NLPs also displayed ∼3.75-fold increment in half-life of the drug in lungs, as compared to 9-Br-Nos suspension following intravenous route of administration. Furthermore, enhanced drug exposure was measured in terms of AUC(last) in lungs following administration of 9-Br-Nos-RR-NLPs, as

  18. Enhanced bioavailability of nerve growth factor with phytantriol lipid-based crystalline nanoparticles in cochlea

    Directory of Open Access Journals (Sweden)

    Bu M

    2015-11-01

    Full Text Available Meng Bu,1,2 Jingling Tang,3 Yinghui Wei,4 Yanhui Sun,1 Xinyu Wang,1 Linhua Wu,2 Hongzhuo Liu1 1School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, People’s Republic of China; 2Department of Pharmacy, the Second Affiliated Hospital, 3School of Pharmacy, Harbin Medical University, Harbin, People’s Republic of China; 4College of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, People’s Republic of China Purpose: Supplementation of exogenous nerve growth factor (NGF into the cochlea of deafened animals rescues spiral ganglion cells from degeneration. However, a safe and potent delivery of therapeutic proteins, such as NGF, to spiral ganglion cells remains one of the greatest challenges. This study presents the development of self-assembled cubic lipid-based crystalline nanoparticles to enhance inner ear bioavailability of bioactive NGF via a round window membrane route.Methods: A novel nanocarrier-entrapped NGF was developed based on phytantriol by a liquid precursor dilution, with Pluronic® F127 and propylene glycol as the surfactant and solubilizer, respectively. Upon dilution of the liquid lipid precursors, monodispersed submicron-sized particles with a slight negative charge formed spontaneously.Results: Biological activity of entrapped NGF was assessed using pheochromocytoma cells with NGF-loaded reservoirs to induce significant neuronal outgrowth, similar to that seen in free NGF-treated controls. Finally, a 3.28-fold increase in inner ear bioavailability was observed after administration of phytantriol lipid-based crystalline nanoparticles as compared to free drug, contributing to an enhanced drug permeability of the round window membrane. Conclusion: Data presented here demonstrate the potential of lipid-based crystalline nanoparticles to improve the outcomes of patients bearing cochlear implants. Keywords: nerve growth factor, lipid-based crystalline nanoparticles, PC12 cells, inner ear drug

  19. Ethnic differences in serum lipids and lipoproteins in overweight/obese African-American and white American women with pre-diabetes: significance of NMR-derived lipoprotein particle concentrations and sizes.

    Science.gov (United States)

    Gaillard, Trudy; Osei, Kwame

    2016-01-01

    African-American women (AAW) suffer disproportionately from higher rates of cardiovascular disease (CVD) mortality compared with white American women (WAW), despite favorable lipid and lipoprotein profile. Therefore, we used nuclear magnetic resonance (NMR) to examine lipoprotein particle concentrations and sizes in overweight/obese AAW and WAW with pre-diabetes. We studied 69 AAW and 41 WAW, with mean age 46.5±11.3 years and body mass index (BMI) 37.8±6.4 kg/m(2). All participants completed standard oral glucose tolerance test (OGTT) and frequently sampled intravenous glucose tolerance test (FSIVGTT). Insulin sensitivity (Si) was calculated using MINIMOD method. Body composition was assessed using dual-energy X-ray absorptiometry (DEXA). Fasting blood was obtained for traditional lipids/lipoproteins and NMR-derived lipoprotein particle sizes and concentrations. We found that AAW with pre-diabetes were more obese (BMI 38.8±6.7 vs 36.0±5.4 kg/m(2), p=0.02) than WAW. Mean Si was not significantly different. However, the mean serum triglycerides were lower, whereas the high-density lipoprotein cholesterol (HDL-C) and apolipoprotein A1 (Apo A1) were significantly higher in AAW versus WAW. The large HDL particle concentration (6.1±3.1 vs 4.6±3.1 µmol/L, p=0.02) was significantly higher in AAW versus WAW. Mean total very low-density lipoprotein (VLDL) particle concentration was lower in AAW versus WAW (39.9±24.4 vs 59.2±25.6 nmol/L, p≤0.001). While mean total LDL particle concentrations were not different, mean small LDL particle concentrations were lower in AAW versus WAW (538.8±294.1 vs 638.4±266 nmol/L, p=0.07). We found a more favorable NMR-derived lipoprotein profile in AAW that extends the traditional antiatherogenic lipid/lipoprotein profiles. Clinically, these favorable lipid/lipoprotein profiles cannot explain the paradoxically higher CVD mortality in AAW than WAW and warrant further prospective outcome studies.

  20. Ethnic differences in serum lipids and lipoproteins in overweight/obese African-American and white American women with pre-diabetes: significance of NMR-derived lipoprotein particle concentrations and sizes

    Science.gov (United States)

    Gaillard, Trudy; Osei, Kwame

    2016-01-01

    Objective African-American women (AAW) suffer disproportionately from higher rates of cardiovascular disease (CVD) mortality compared with white American women (WAW), despite favorable lipid and lipoprotein profile. Therefore, we used nuclear magnetic resonance (NMR) to examine lipoprotein particle concentrations and sizes in overweight/obese AAW and WAW with pre-diabetes. Participants and methods We studied 69 AAW and 41 WAW, with mean age 46.5±11.3 years and body mass index (BMI) 37.8±6.4 kg/m2. All participants completed standard oral glucose tolerance test (OGTT) and frequently sampled intravenous glucose tolerance test (FSIVGTT). Insulin sensitivity (Si) was calculated using MINIMOD method. Body composition was assessed using dual-energy X-ray absorptiometry (DEXA). Fasting blood was obtained for traditional lipids/lipoproteins and NMR-derived lipoprotein particle sizes and concentrations. Results We found that AAW with pre-diabetes were more obese (BMI 38.8±6.7 vs 36.0±5.4 kg/m2, p=0.02) than WAW. Mean Si was not significantly different. However, the mean serum triglycerides were lower, whereas the high-density lipoprotein cholesterol (HDL-C) and apolipoprotein A1 (Apo A1) were significantly higher in AAW versus WAW. The large HDL particle concentration (6.1±3.1 vs 4.6±3.1 µmol/L, p=0.02) was significantly higher in AAW versus WAW. Mean total very low-density lipoprotein (VLDL) particle concentration was lower in AAW versus WAW (39.9±24.4 vs 59.2±25.6 nmol/L, p≤0.001). While mean total LDL particle concentrations were not different, mean small LDL particle concentrations were lower in AAW versus WAW (538.8±294.1 vs 638.4±266 nmol/L, p=0.07). Conclusions We found a more favorable NMR-derived lipoprotein profile in AAW that extends the traditional antiatherogenic lipid/lipoprotein profiles. Clinically, these favorable lipid/lipoprotein profiles cannot explain the paradoxically higher CVD mortality in AAW than WAW and warrant further

  1. Effect of short-term regional traffic restriction on urban submicron particulate pollution.

    Science.gov (United States)

    Zhao, Suping; Yu, Ye

    2017-05-01

    During the 2013 and 2015 Lanzhou International Marathon Events (LIME1 and LIME2), the local government made a significant effort to improve traffic conditions and air quality by implementing traffic restriction measures. To fill the gap in information on the effect of short-period (several hours) traffic control on urban air quality, submicron particle size distributions and meteorological data were measured simultaneously during June 2013 and June 2015 in urban Lanzhou. The number and surface area concentrations of particles in the 100-200nm range declined by 67.2% and 65.0% for LIME1 due to traffic control, while they decreased by 39.2% and 37.1% for LIME2. The impact of traffic restriction on air pollution near the sampling site lagged behind the traffic control period for LIME2. In addition, the effect of traffic restriction on air pollution near the sampling site was dependent on the distance between the relative orientation of the sampling site and traffic-restricted zones, as well as meteorological conditions such as wind direction. The influence of traffic restrictions on the particle concentrations differed for different particle sizes. The size range most affected by traffic restriction was 60-200 and 60-300nm for number and surface area concentrations in the urban environment, respectively, while for the particle volume concentration it was the 100-600nm range. This study will provide a basis for implementation of future urban traffic-induced particulate pollution control measures. Copyright © 2016. Published by Elsevier B.V.

  2. Comparative study of pulmonary responses to nano- and submicron-sized ferric oxide in rats.

    Science.gov (United States)

    Zhu, Mo-Tao; Feng, Wei-Yue; Wang, Bing; Wang, Tian-Cheng; Gu, Yi-Qun; Wang, Meng; Wang, Yun; Ouyang, Hong; Zhao, Yu-Liang; Chai, Zhi-Fang

    2008-05-21

    Ferric oxide (Fe(2)O(3)) nanoparticles are of considerable interest for application in nanotechnology related fields. However, as iron being a highly redox-active transition metal, the safety of iron nanomaterials need to be further studied. In this study, the size, dose and time dependent of Fe(2)O(3) nanoparticle on pulmonary and coagulation system have been studied after intratracheal instillation. The Fe(2)O(3) nanoparticles with mean diameters of 22 and 280 nm, respectively, were intratracheally instilled to male Sprague Dawley rats at low (0.8 mg/kgbw) and high (20 mg/kgbw) doses. The toxic effects were monitored in the post-instilled 1, 7 and 30 days. Our results showed that the Fe(2)O(3) nanoparticle exposure could induce oxidative stress in lung. Alveolar macrophage (AM) over-loading of phagocytosed nanoparticle by high dose treatment had occurred, while the non-phagocytosed particles were found entering into alveolar epithelial in day 1 after exposure. Several inflammatory reactions including inflammatory and immune cells increase, clinical pathological changes: follicular hyperplasia, protein effusion, pulmonary capillary vessel hyperaemia and alveolar lipoproteinosis in lung were observed. The sustain burden of particles in AM and epithelium cells has caused lung emphysema and pro-sign of lung fibrosis. At the post-instilled day 30, the typical coagulation parameters, prothrombin time (PT) and activated partial thromboplastin time (APTT) in blood of low dose 22 nm-Fe(2)O(3) treated rats were significantly longer than the controls. We concluded that both of the two-sized Fe(2)O(3) particle intratracheal exposure could induce lung injury. Comparing with the submicron-sized Fe(2)O(3) particle, the nano-sized Fe(2)O(3) particle may increase microvascular permeability and cell lysis in lung epitheliums and disturb blood coagulation parameters significantly.

  3. Submicron Defect Detection in Periodic Structures Using Photorefractive Holography

    Science.gov (United States)

    Uhrich, Craig Edward

    Detection of defects in periodic objects is an important step in the manufacture of integrated circuits, particularly memory chips which are highly repetitive. As feature sizes shrink below 1 mum, automated detection of sub-micron defects becomes necessary. We present a real-time holographic system which allows the detection of sub-micron defects in periodic structures. The inspection technique is a marriage of Fourier spatial filtering and real-time phase conjugate holography. The system output is a near diffraction limited image of any defects in the pattern (defined to be any deviations from periodicity). Real-time holographic recording allows the system to adapt to the orientation and period of the object. The early chapters introduce the photorefractive effect and the generation of the phase conjugate of an optical wavefront using Bi_{12} SiO_{20}. Relevant properties of the optical Fourier transform are also discussed. The following sections present the system design rules and experimental techniques which allow the system to reliably detect sub-micron defects. The most important improvements over previous demonstrations are (1) a novel write/read holographic process which increases phase conjugate reflectivity by orders of magnitude, (2) control of the light polarization to allow efficient object illumination and collection of the diffracted signal, (3) avoidance of noise by moving the crystal away from the origin of the Fourier plane, and (4) compensation for the crystal aberrations with a holographic optical element. The final chapter presents results which clearly show enhancement of sub-micron defects and near perfect suppression of the surrounding periodic patterns. An area larger than 1 mm^2 is inspected in 20-60 seconds. Over 90% of the 0.5 mu m diameter defects on glass masks (viewed in reflection) are detected, and approximately 80% of defects in the 0.2 -0.3 μm range are found. On silicon wafers, the results are even better with over a 95% success

  4. Noise estimation for deep sub-micron integrated circuits

    Institute of Scientific and Technical Information of China (English)

    陈彬; 杨华中; 汪惠

    2001-01-01

    Noise analysis and avoidance are an increasingly critical step in the design of deep submicron (DSM) integrated circuits (Ics). The crosstalk between neighboring interconnects gradually becomes the main noise sources in DSM Ics. We introduce an efficient and accurate noise-evaluation method for capacitively coupled nets of Ics. The method holds for a victim net with arbitrary number of aggressive nets under ramp input excitation. For common RC nets extracted by electronic design automation (EDA) tools, the deviation between our method and HSPICE is under 10%.

  5. Multiscale Modeling of Red Blood Cells Squeezing through Submicron Slits

    Science.gov (United States)

    Peng, Zhangli; Lu, Huijie

    2016-11-01

    A multiscale model is applied to study the dynamics of healthy red blood cells (RBCs), RBCs in hereditary spherocytosis, and sickle cell disease squeezing through submicron slits. This study is motivated by the mechanical filtration of RBCs by inter-endothelial slits in the spleen. First, the model is validated by comparing the simulation results with experiments. Secondly, the deformation of the cytoskeleton in healthy RBCs is investigated. Thirdly, the mechanisms of damage in hereditary spherocytosis are investigated. Finally, the effects of cytoplasm and membrane viscosities, especially in sickle cell disease, are examined. The simulations results provided guidance for future experiments to explore the dynamics of RBCs under extreme deformation.

  6. Particle size distribution control of Pt particles used for particle gun

    Science.gov (United States)

    Ichiji, M.; Akiba, H.; Nagao, H.; Hirasawa, I.

    2017-07-01

    The purpose of this study is particle size distribution (PSD) control of submicron sized Pt particles used for particle gun. In this report, simple reaction crystallization is conducted by mixing H2PtCl6 and ascorbic acid. Without the additive, obtained Pt particles have broad PSD and reproducibility of experiment is low. With seeding, Pt particles have narrow PSD and reproducibility improved. Additionally, mean particle diameter of 100-700 nm is controlled by changing seeding amount. Obtained particles are successfully characterized as Pt by XRD results. Moreover, XRD spectra indicate that obtained particles are polycrystals. These experimental results suggest that seeding consumed nucleation, as most nuclei attached on the seed surface. This mechanism virtually restricted nucleation to have narrow PSD can be obtained.

  7. Investigation of protein distribution in solid lipid particles and its impact on protein release using coherent anti-Stokes Raman scattering microscopy

    DEFF Research Database (Denmark)

    Christophersen, Philip C.; Birch, Ditlev; Saarinen, Jukka

    2015-01-01

    The aim of this study was to gain new insights into protein distribution in solid lipid microparticles (SLMs) and subsequent release mechanisms using a novel label-free chemical imaging method, coherent anti-Stokes Raman scattering (CARS) microscopy. Lysozyme-loaded SLMs were prepared using...... different lipids with lysozyme incorporated either as an aqueous solution or as a solid powder. Lysozyme distribution in SLMs was investigated using CARS microscopy with supportive structural analysis using electron microscopy. The release of lysozyme from SLMs was investigated in a medium simulating......-destructive method for elucidating the distribution of lysozyme in SLMs. The interpretation of protein distribution and release during lipolysis enabled elucidation of protein release mechanisms. In future, CARS microscopy analysis could facilitate development of a wide range of protein-lipid matrices with tailor...

  8. Atmospheric pressure plasma assisted calcination of composite submicron fibers

    Science.gov (United States)

    Medvecká, Veronika; Kováčik, Dušan; Tučeková, Zlata; Zahoranová, Anna; Černák, Mirko

    2016-08-01

    The plasma assisted calcination of composite organic/inorganic submicron fibers for the preparation of inorganic fibers in submicron scale was studied. Aluminium butoxide/polyvinylpyrrolidone fibers prepared by electrospinning were treated using low-temperature plasma generated by special type of dielectric barrier discharge, so called diffuse coplanar surface barrier discharge (DCSBD) at atmospheric pressure in ambient air, synthetic air, oxygen and nitrogen. Effect of plasma treatment on base polymer removal was investigated by using Attenuated total reflectance - Fourier transform infrared (ATR-FTIR) spectroscopy. Influence of working gas on the base polymer reduction was studied by energy-dispersive X-ray spectroscopy (EDX) and CHNS elemental analysis. Changes in fibers morphology were observed by scanning electron microscopy (SEM). High efficiency of organic template removal without any degradation of fibers was observed after plasma treatment in ambient air. Due to the low-temperature approach and short exposure time, the plasma assisted calcination is a promising alternative to the conventional thermal calcination. Contribution to the topical issue "6th Central European Symposium on Plasma Chemistry (CESPC-6)", edited by Nicolas Gherardi, Ester Marotta and Cristina Paradisi

  9. Optical manipulation of lipid and polymer nanotubes with optical tweezers

    Science.gov (United States)

    Reiner, Joseph E.; Kishore, Rani; Pfefferkorn, Candace; Wells, Jeffrey; Helmerson, Kristian; Howell, Peter; Vreeland, Wyatt; Forry, Samuel; Locascio, Laurie; Reyes-Hernandez, Darwin; Gaitan, Michael

    2004-10-01

    Using optical tweezers and microfluidics, we stretch either the lipid or polymer membranes of liposomes or polymersomes, respectively, into long nanotubes. The membranes can be grabbed directly with the optical tweezers to produce sub-micron diameter tubes that are several hundred microns in length. We can stretch tubes up to a centimeter in length, limited only by the travel of our microscope stage. We also demonstrate the cross linking of a pulled polymer nanotube.

  10. 肝癌靶向液态氟碳脂质微球造影剂的体外寻靶实验研究%Targeting study in vitro of human hepatocellular carcinoma-targeted perfluorocarbon lipid particles

    Institute of Scientific and Technical Information of China (English)

    陈松; 王志刚; 康娟; 李攀; 郑元义; 伍星; 杨春江; 许川山

    2008-01-01

    目的 制备液态氟碳脂质微球造影剂并研究其体外基本特性,再引入抗人肝癌细胞单克隆抗体,采用生物素亲和素法,进行体外靶向结合的研究.方法 采用旋转蒸发法和高压均质法制备一种纳米液态氟碳脂质微球造影剂,观察其外观、形态、大小及分布情况,计算其浓度,并测定其粒径、电位;制备生物素的抗人肝癌细胞单克隆抗体HAb18,用HABA/Avidin试剂盒检测抗体的生物素化程度;制备NBD标记的生物素化的微球,采用生物素亲和素法研究其体外靶向作用.结果 所制备的液态氟碳脂质微球造影剂外观呈乳白色的混悬液,镜下观察,微球形态圆整,大小均一,性质稳定,平均粒径171.9 nm;采用生物素亲和素法制备的NBD标记的生物素化的微球可靶向结合到靶细胞上.结论 成功制备出稳定的纳米液态氟碳脂质微球造影剂,并引入抗人肝癌细胞单克隆抗体,通过生物素亲和素系统可将其特异结合到靶细胞上.%Objective To develop perfluorocarbon lipid particles and investigate their basic properties,and target them to human hepatocellular carcinoma cells in vitro by hepatoma monocolonal antibody HAb18 with avidin-biotin interaction.Methods Rotary evaporation and high pressure homogen were used to prepare perfluorocarbon lipid particles, and the appearance and distribution of them were investigated by microscope and electron microscope, the concentration and the size and electric potential were detected.The biotinylated monoclonal antibody HAbl8 was prepared, then the biotinylated degree of the antibody was determined.The biotinylated perfluoroearbon lipid particles labelled with NBD were prepared and targeted to human hepatocellular carcinoma cells in vitro with avidin-biotin interaction.Results These perfluorocarbon lipid nanoparticles were uniform and stable,and the mean diameter of them was 171.9 nm.Hepatocellular carcinoma cells were surrounded by the

  11. A quantitative assessment of the total inward leakage of NaCl aerosol representing submicron-size bioaerosol through N95 filtering facepiece respirators and surgical masks.

    Science.gov (United States)

    Rengasamy, Samy; Eimer, Benjamin C; Szalajda, Jonathan

    2014-01-01

    Respiratory protection provided by a particulate respirator is a function of particle penetration through filter media and through faceseal leakage. Faceseal leakage largely contributes to the penetration of particles through a respirator and compromises protection. When faceseal leaks arise, filter penetration is assumed to be negligible. The contribution of filter penetration and faceseal leakage to total inward leakage (TIL) of submicron-size bioaerosols is not well studied. To address this issue, TIL values for two N95 filtering facepiece respirator (FFR) models and two surgical mask (SM) models sealed to a manikin were measured at 8 L and 40 L breathing minute volumes with different artificial leak sizes. TIL values for different size (20-800 nm, electrical mobility diameter) NaCl particles representing submicron-size bioaerosols were measured using a scanning mobility particle sizer. Efficiency of filtering devices was assessed by measuring the penetration against NaCl aerosol similar to the method used for NIOSH particulate filter certification. Results showed that the most penetrating particle size (MPPS) was ∼45 nm for both N95 FFR models and one of the two SM models, and ∼350 nm for the other SM model at sealed condition with no leaks as well as with different leak sizes. TIL values increased with increasing leak sizes and breathing minute volumes. Relatively, higher efficiency N95 and SM models showed lower TIL values. Filter efficiency of FFRs and SMs influenced the TIL at different flow rates and leak sizes. Overall, the data indicate that good fitting higher-efficiency FFRs may offer higher protection against submicron-size bioaerosols.

  12. Interaction between submicron COD crystals and renal epithelial cells

    Directory of Open Access Journals (Sweden)

    Peng H

    2012-08-01

    Full Text Available Hua Peng1,2 Jian-Ming Ouyang1,2 Xiu-Qiong Yao1, Ru-E Yang11Department of Chemistry, Jinan University, 2Institute of Biomineralization and Lithiasis Research, Jinan University, Guangzhou, ChinaObjectives: This study aims to investigate the adhesion characteristics between submicron calcium oxalate dihydrate (COD with a size of 150 ± 50 nm and African green monkey kidney epithelial cells (Vero cells before and after damage, and to discuss the mechanism of kidney stone formation.Methods: Vero cells were oxidatively injured by hydrogen peroxide to establish a model of injured cells. Scanning electron microscopy was used to observe Vero–COD adhesion. Inductively coupled plasma emission spectrometry was used to quantitatively measure the amount of adhered COD microcrystals. Nanoparticle size analyzer and laser scanning confocal microscopy were performed to measure the change in the zeta potential on the Vero cell surface and the change in osteopontin expression during the adhesion process, respectively. The level of cell injury was evaluated by measuring the changes in malonaldehyde content, and cell viability during the adhesion process.Results: The adhesion capacity of Vero cells in the injury group to COD microcrystals was obviously stronger than that of Vero cells in the control group. After adhesion to COD, cell viability dropped, both malonaldehyde content and cell surface zeta potential increased, and the fluorescence intensity of osteopontin decreased because the osteopontin molecules were successfully covered by COD. Submicron COD further damaged the cells during the adhesion process, especially for Vero cells in the control group, leading to an elevated amount of attached microcrystals.Conclusion: Submicron COD can further damage injured Vero cells during the adhesion process. The amount of attached microcrystals is proportional to the degree of cell damage. The increased amount of microcrystals that adhered to the injured epithelial

  13. A novel approach to oral iron delivery using ferrous sulphate loaded solid lipid nanoparticles.

    Science.gov (United States)

    Zariwala, M Gulrez; Elsaid, Naba; Jackson, Timothy L; Corral López, Francisco; Farnaud, Sebastien; Somavarapu, Satyanarayana; Renshaw, Derek

    2013-11-18

    Iron (Fe) loaded solid lipid nanoparticles (SLN's) were formulated using stearic acid and iron absorption was evaluated in vitro using the cell line Caco-2 with intracellular ferritin formation as a marker of iron absorption. Iron loading was optimised at 1% Fe (w/w) lipid since an inverse relation was observed between initial iron concentration and SLN iron incorporation efficiency. Chitosan (Chi) was included to prepare chitosan coated SLN's. Particle size analysis revealed a sub-micron size range (300.3±31.75 nm to 495.1±80.42 nm), with chitosan containing particles having the largest dimensions. As expected, chitosan (0.1%, 0.2% and 0.4% w/v) conferred a net positive charge on the particle surface in a concentration dependent manner. For iron absorption experiments equal doses of Fe (20 μM) from selected formulations (SLN-FeA and SLN-Fe-ChiB) were added to Caco-2 cells and intracellular ferritin protein concentrations determined. Caco-2 iron absorption from SLN-FeA (583.98±40.83 ng/mg cell protein) and chitosan containing SLN-Fe-ChiB (642.77±29.37 ng/mg cell protein) were 13.42% and 24.9% greater than that from ferrous sulphate (FeSO4) reference (514.66±20.43 ng/mg cell protein) (p≤0.05). We demonstrate for the first time preparation, characterisation and superior iron absorption in vitro from SLN's, suggesting the potential of these formulations as a novel system for oral iron delivery. Copyright © 2013 Elsevier B.V. All rights reserved.

  14. Large-scale self-assembly of uniform submicron silver sulfide material driven by precise pressure control

    Science.gov (United States)

    Qi, Juanjuan; Chen, Ke; Zhang, Shuhao; Yang, Yun; Guo, Lin; Yang, Shihe

    2017-03-01

    The controllable self-assembly of nanosized building blocks into larger specific structures can provide an efficient method of synthesizing novel materials with excellent properties. The self-assembly of nanocrystals by assisted means is becoming an extremely active area of research, because it provides a method of producing large-scale advanced functional materials with potential applications in the areas of energy, electronics, optics, and biologics. In this study, we applied an efficient strategy, namely, the use of ‘pressure control’ to the assembly of silver sulfide (Ag2S) nanospheres with a diameter of approximately 33 nm into large-scale, uniform Ag2S sub-microspheres with a size of about 0.33 μm. More importantly, this strategy realizes the online control of the overall reaction system, including the pressure, reaction time, and temperature, and could also be used to easily fabricate other functional materials on an industrial scale. Moreover, the thermodynamics and kinetics parameters for the thermal decomposition of silver diethyldithiocarbamate (Ag(DDTC)) are also investigated to explore the formation mechanism of the Ag2S nanosized building blocks which can be assembled into uniform sub-micron scale architecture. As a method of producing sub-micron Ag2S particles by means of the pressure-controlled self-assembly of nanoparticles, we foresee this strategy being an efficient and universally applicable option for constructing other new building blocks and assembling novel and large functional micromaterials on an industrial scale.

  15. Large-scale self-assembly of uniform submicron silver sulfide material driven by precise pressure control.

    Science.gov (United States)

    Qi, Juanjuan; Chen, Ke; Zhang, Shuhao; Yang, Yun; Guo, Lin; Yang, Shihe

    2017-03-10

    The controllable self-assembly of nanosized building blocks into larger specific structures can provide an efficient method of synthesizing novel materials with excellent properties. The self-assembly of nanocrystals by assisted means is becoming an extremely active area of research, because it provides a method of producing large-scale advanced functional materials with potential applications in the areas of energy, electronics, optics, and biologics. In this study, we applied an efficient strategy, namely, the use of 'pressure control' to the assembly of silver sulfide (Ag2S) nanospheres  with a diameter of approximately 33 nm into large-scale, uniform Ag2S sub-microspheres with a size of about 0.33 μm. More importantly, this strategy realizes the online control of the overall reaction system, including the pressure, reaction time, and temperature, and could also be used to easily fabricate other functional materials on an industrial scale. Moreover, the thermodynamics and kinetics parameters for the thermal decomposition of silver diethyldithiocarbamate (Ag(DDTC)) are also investigated to explore the formation mechanism of the Ag2S nanosized building blocks which can be assembled into uniform sub-micron scale architecture. As a method of producing sub-micron Ag2S particles by means of the pressure-controlled self-assembly of nanoparticles, we foresee this strategy being an efficient and universally applicable option for constructing other new building blocks and assembling novel and large functional micromaterials on an industrial scale.

  16. Optimization of the crystallinity of polypropylene/submicronic-talc composites: The role of filler ratio and cooling rate

    Directory of Open Access Journals (Sweden)

    A. Makhlouf

    2016-03-01

    Full Text Available Micronic and submicronic mineral fillers recently appeared as efficient reinforcing agents for polyolefins in addition to the benefit of bypassing the exfoliation/dispersion problem encountered in the case of incorporation of nanoscopic fillers such as clay. Submicronic-talc, designated as μ-talc, belongs to this kind of new fillers. This work was aimed at searching to optimize the crystallinity ratio of isotactic polypropylene in the presence of μ-talc in relation to the filler ratio of the composites and the cooling rate from the melt. In order to highlight the efficiency of the μ-talc on the crystallization of polypropylene comparison has been made with PP composites containing conventional talc particles. The study has been carried out on samples having μ-talc weight fractions covering the range 3–30%. In the context of optimizing the crystallinity ratio of the polypropylene matrix in the composites, calorimetric experiments have been planned using a full factorial design. The results were statistically processed by analysis of the variance via mathematical models for predicting the crystallinity ratio in relation to the cooling rate and the filler ratio. Contour graphs have been plotted to determine the effect of each parameter on crystallinity. The cooling rate proved to have a significantly stronger influence on crystallinity than the type and content of filler.

  17. Microscopic methods in analysis of submicron phospholipid dispersions

    Directory of Open Access Journals (Sweden)

    Płaczek Marcin

    2016-03-01

    Full Text Available Microscopy belongs to the group of tests, used in pharmaceutical technology, that despite the lapse of time and the development of new analytical methods, still remain irreplaceable for the characterization of dispersed drug dosage forms (e.g., suspensions and emulsions. To obtain complete description of a specific drug formulation, such as parenteral colloidal products, a combination of different microscopic techniques is sometimes required. Electron microscopy methods are the most useful ones; however, even such basic methods as optical microscopy may be helpful for determination of some properties of a sample. The publication explicates the most popular microscopical techniques used nowadays for characterization of the morphology of nanoparticles suspended in pharmaceutical formulations; ad vantages and disadvantages of these methods are also discussed. Parenteral submicron formulations containing lecithin or a particular phospholipid were chosen as examples.

  18. Submicron cubic boron nitride as hard as diamond

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Guoduan; Kou, Zili, E-mail: kouzili@scu.edu.cn, E-mail: yanxz@hpstar.ac.cn; Lei, Li; Peng, Fang; Wang, Qiming; Wang, Kaixue; Wang, Pei; Li, Liang; Li, Yong; Wang, Yonghua [Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065 (China); Yan, Xiaozhi, E-mail: kouzili@scu.edu.cn, E-mail: yanxz@hpstar.ac.cn; Li, Wentao [Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065 (China); Center for High Pressure Science and Technology Advanced Research (HPSTAR), Shanghai 201203 (China); Bi, Yan [Institute of Fluid Physics and National Key Laboratory of Shockwave and Detonation Physic, China Academy of Engineering Physics, Mianyang 621900 (China); Leng, Yang [Department of Mechanical Engineering, Hong Kong University of Science and Technology, Kowloon, Hong Kong (China); He, Duanwei [Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065 (China); Institute of Fluid Physics and National Key Laboratory of Shockwave and Detonation Physic, China Academy of Engineering Physics, Mianyang 621900 (China)

    2015-03-23

    Here, we report the sintering of aggregated submicron cubic boron nitride (sm-cBN) at a pressure of 8 GPa. The sintered cBN compacts exhibit hardness values comparable to that of single crystal diamond, fracture toughness about 5-fold that of cBN single crystal, in combination with a high oxidization temperature. Thus, another way has been demonstrated to improve the mechanical properties of cBN besides reducing the grain size to nano scale. In contrast to other ultrahard compacts with similar hardness, the sm-cBN aggregates are better placed for potential industrial application, as their relative low pressure manufacturing perhaps be easier and cheaper.

  19. Coherent Magnetic Switching in a Permalloy Submicron Junction

    CERN Document Server

    Wang, Junlin; Lu, Xianyang; Zhang, Jason; Ling, Hua; Wu, Jing; Zhou, Yan; Xu, Yongbing

    2016-01-01

    This work provides a numerical micromagnetic study of the magnetic switching of a submicron magnetic junction in a Permalloy (Ni80Fe20) cross structure. The simulation results demonstrate that the magnetic domain at the junction can be controlled to switch coherently by the applied magnetic field. This coherent magnetic switching in the cross structure has been found to be reversible and the 2-bit information can be written in the magnetic junction. For information storage, this kind of device can also realize the function of a quaternary arithmetic unit. By varying the direction of the applied magnetic field, we have demonstrated that this magnetic junction could be the building block for a magnetoresistive random access memory (MRAM) or a quaternary magnetic arithmetic unit.

  20. Chemical strategies for die/wafer submicron alignment and bonding.

    Energy Technology Data Exchange (ETDEWEB)

    Martin, James Ellis; Baca, Alicia I.; Chu, Dahwey; Rohwer, Lauren Elizabeth Shea

    2010-09-01

    This late-start LDRD explores chemical strategies that will enable sub-micron alignment accuracy of dies and wafers by exploiting the interfacial energies of chemical ligands. We have micropatterned commensurate features, such as 2-d arrays of micron-sized gold lines on the die to be bonded. Each gold line is functionalized with alkanethiol ligands before the die are brought into contact. The ligand interfacial energy is minimized when the lines on the die are brought into registration, due to favorable interactions between the complementary ligand tails. After registration is achieved, standard bonding techniques are used to create precision permanent bonds. We have computed the alignment forces and torque between two surfaces patterned with arrays of lines or square pads to illustrate how best to maximize the tendency to align. We also discuss complex, aperiodic patterns such as rectilinear pad assemblies, concentric circles, and spirals that point the way towards extremely precise alignment.

  1. SEMICONDUCTOR DEVICES: Deep submicron PDSOI thermal resistance extraction

    Science.gov (United States)

    Jianhui, Bu; Jinshun, Bi; Linmao, Xi; Zhengsheng, Han

    2010-09-01

    Deep submicron partially depleted silicon on insulator (PDSOI) MOSFETs with H-gate were fabricated based on the 0.35 μm SOI process developed by the Institute of Microelectronics of the Chinese Academy of Sciences. Because the self-heating effect (SHE) has a great influence on SOI, extractions of thermal resistance were done for accurate circuit simulation by using the body-source diode as a thermometer. The results show that the thermal resistance in an SOI NMOSFET is lower than that in an SOI PMOSFET; and the thermal resistance in an SOI NMOSFET with a long channel is lower than that with a short channel. This offers a great help to SHE modeling and parameter extraction.

  2. One year online chemical speciation of submicron particulate matter (PM1) sampled at a French industrial and coastal site

    Science.gov (United States)

    Zhang, Shouwen; Riffault, Véronique; Dusanter, Sébastien; Augustin, Patrick; Fourmentin, Marc; Delbarre, Hervé

    2015-04-01

    The harbor of Dunkirk (Northern France) is surrounded by different industrial plants (metallurgy, petrochemistry, food processing, power plant, etc.), which emit gaseous and particulate pollutants such as Volatile Organic Compounds (VOCs), oxides of nitrogen (NOx) and sulfur (SO2), and submicron particles (PM1). These emissions are poorly characterized and their impact on neighboring urban areas has yet to be assessed. Studies are particularly needed in this type of complex environments to get a better understanding of PM1sources, especially from the industrial sector, their temporal variability, and their transformation. Several instruments, capable of real-time measurements (temporal resolution ≤ 30 min), were deployed at a site located downwind from the industrial area of Dunkirk for a one-year duration (July 2013-September 2014). An Aerosol Chemical Speciation Monitor (ACSM) and an Aethalometer monitored the main chemical species in the non-refractory submicron particles and black carbon, respectively. Concomitant measurements of trace gases and wind speed and direction were also performed. This dataset was analyzed considering four wind sectors, characteristics of marine, industrial, industrial-urban, and urban influences, and the different seasons. We will present a descriptive analysis of PM1, showing strong variations of ambient concentrations, as well as evidences of SO2 to SO4 gas-particle conversion when industrial plumes reached the monitoring site. The organic fraction measured by ACSM (37% of the total mass on average) was analyzed using a source-receptor model based on Positive Matrix Factorization (PMF) to identify chemical signatures of main emission sources and to quantify the contribution of each source to the PM1 budget given the wind sector. Four main factors were identified: hydrocarbon organic aerosol (HOA), oxygenated organic aerosol (OOA), biomass burning organic aerosol (BBOA) and cooking-like organic aerosol (COA). Overall, the total PM

  3. Controlled fabrication of α-GaOOH with a novel needle-like submicron tubular structure and its enhanced photocatalytic performance

    Energy Technology Data Exchange (ETDEWEB)

    Xu, X.; Bi, K.; Huang, K.; Liang, C.; Lin, S. [State Key Laboratory of Information Photonics and Optical Communications & School of Science, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Wang, W.J., E-mail: wjwang@iphy.ac.cn [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Yang, T.Z. [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Liu, J. [School of Materials Science and Engineering, Central South University, Changsha, Hunan 410083 (China); Fan, D.Y.; Yang, H.J.; Wang, Y.G. [State Key Laboratory of Information Photonics and Optical Communications & School of Science, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Lei, M., E-mail: minglei@bupt.edu.cn [State Key Laboratory of Information Photonics and Optical Communications & School of Science, Beijing University of Posts and Telecommunications, Beijing 100876 (China)

    2015-09-25

    Highlights: • A novel tubular α-GaOOH has been firstly fabricated by a hydrothermal route. • The concentration of OH{sup −} plays an important role in the formation of the tube. • The photocatalysis of α-GaOOH improves much more than other catalysts. • The enhanced photocatalytic activity can be attributed to the intrinsic defects. - Abstract: Orthorhombic gallium oxide hydroxide (α-GaOOH) with a novel needle-like submicron tubular structure has been firstly fabricated by an organometallic reactant-assisted hydrothermal route. A possible fabrication process indicates that the concentration of OH{sup −} ions plays an important role in the formation of submicron tube. Moreover, other four kinds of shape-controllable α-GaOOH particles of nano-, submicron- and micro-size have also been successfully synthesized by changing the pH values of solvent. The photoluminescence (PL) performance demonstrates that there are a plenty of intrinsic defects in α-GaOOH. Furthermore, the photocatalytic activity of α-GaOOH with different morphologies was evaluated by degrading methylene blue (MB) aqueous solution. The efficiency of α-GaOOH with a novel tubular structure improves much more than other catalysts. The enhanced photocatalytic activity can be attributed to the effective inhibition of photo-generated electron–hole pair’s recombination resulted from intrinsic defects.

  4. Field electron emission from undoped, continuous, submicron-thick diamond films

    Science.gov (United States)

    Ternyak, O.; Akhvlediani, R.; Hoffman, A.; Wong, W. K.; Lee, S. T.; Lifshitz, Y.; Daren, S.; Cheifetz, E.

    2005-12-01

    The present work shows that the field electron emission (FEE) properties of polycrystalline diamond films can be enhanced by control over the film thickness. The FEE properties of undoped, continuous, and smooth submicron-thick diamond films with initial nucleation densities of ˜5×1010particles/cm2 were investigated as a function of diamond film thickness. A set of films with thickness ranging from 70-100to830nm yielded turn-on field values of 6-8V/μm and threshold field values of 8.5-17.5V/μm (for 0.3μA/cm2), respectively, without any conditioning. It was found that the films of thickness up to ˜370nm can sustain stable current density as high as 0.1A/cm2 without morphological modification. The thicker films, however, suffer from a strong degradation of the film and breakdown. The best FEE (lower turn-on and threshold fields and morphological stability) was obtained for a thin (100nm) continuous diamond film. This result is suggested to be attributed mainly to the efficient electron conduction from the back contact to the surface.

  5. A new circuit technique for reduced leakage current in Deep Submicron CMOS technologies

    Directory of Open Access Journals (Sweden)

    A. Schmitz

    2005-01-01

    Full Text Available Modern CMOS processes in the Deep Submicron regime are restricted to supply voltages below 2 volts and further to account for the transistors' field strength limitations and to reduce the power per logic gate. To maintain the high switching performance, the threshold voltage must be scaled according with the supply voltage. However, this leads to an increased subthreshold current of the transistors in standby mode (VGS=0. Another source of leakage is gate current, which becomes significant for gate oxides of 3nm and below. We propose a Self-Biasing Virtual Rails (SBVR - CMOS technique which acts like an adaptive local supply voltage in case of standby mode. Most important sources of leakage currents are reduced by this technique. Moreover, SBVR-CMOS is capable of conserving stored information in sleep mode, which is vital for memory circuits. Memories are exposed to radiation causing soft errors. This well-known problem becomes even worse in standby mode of typical SRAMs, that have low driving performance to withstand alpha particle hits. In this paper, a 16-transistor SRAM cell is proposed, which combines the advantage of extremely low leakage currents with a very high soft error stability.

  6. Immunogenicity Studies of Bivalent Inactivated Virions of EV71/CVA16 Formulated with Submicron Emulsion Systems

    Directory of Open Access Journals (Sweden)

    Chih-Wei Lin

    2014-01-01

    Full Text Available We assessed two strategies for preparing candidate vaccines against hand, foot, and mouth disease (HFMD caused mainly by infections of enterovirus (EV 71 and coxsackievirus (CV A16. We firstly design and optimize the potency of adjuvant combinations of emulsion-based delivery systems, using EV71 candidate vaccine as a model. We then perform immunogenicity studies in mice of EV71/CVA16 antigen combinations formulated with PELC/CpG. A single dose of inactivated EV71 virion (0.2 μg emulsified in submicron particles was found (i to induce potent antigen-specific neutralizing antibody responses and (ii consistently to elicit broad antibody responses against EV71 neutralization epitopes. A single dose immunogenicity study of bivalent activated EV71/CVA16 virion formulated with either Alum or PELC/CpG adjuvant showed that CVA16 antigen failed to elicit CVA16 neutralizing antibody responses and did not affect EV71-specific neutralizing antibody responses. A boosting dose of emulsified EV71/CVA16 bivalent vaccine candidate was found to be necessary to achieve high seroconversion of CVA16-specific neutralizing antibody responses. The current results are important for the design and development of prophylactic vaccines against HFMD and other emerging infectious diseases.

  7. Spray freeze granulation of submicron alumina and its sintering behavior via spark plasma sintering

    Directory of Open Access Journals (Sweden)

    Liu Wei

    2015-01-01

    Full Text Available Spray freeze granulation is an improved method based on spray granulation, solving many limitations of spray granulation. In this work, spray freeze granulation of submicron alumina is performed to explore the possibility of industrial-scale production of dense alumina via spark plasma sintering. Powder pretreatment such as sedimentation and the selection of granules with the appropriate size are employed for the maximum use of the high qualified as-prepared granules and granule sliding, which would provide a guidance for the industrial-scale production. Debound granules were densified via SPS and the corresponding sintering behaviors such as the recorded shrinkage and shrinkage rate were discussed. The comparison of sintering behaviors between granulated and as-received powder are conducted to identify the role of spray freeze granulation in sinterability for dense alumina. The Vickers hardness (Hv and the fracture toughness (KIC of the freeze granulated body are higher than the corresponding properties of the as-received body due to the more homogenous microstructure with little agglomeration in the particle packing after freeze granulation.

  8. Lipid somersaults

    DEFF Research Database (Denmark)

    Günther-Pomorski, Thomas; Menon, Anant K.

    2016-01-01

    Membrane lipids diffuse rapidly in the plane of the membrane but their ability to flip spontaneously across a membrane bilayer is hampered by a significant energy barrier. Thus spontaneous flip-flop of polar lipids across membranes is very slow, even though it must occur rapidly to support divers...

  9. Light emitting diode with high aspect ratio submicron roughness for light extraction and methods of forming

    Science.gov (United States)

    Li, Ting

    2013-08-13

    The surface morphology of an LED light emitting surface is changed by applying a reactive ion etch (RIE) process to the light emitting surface. High aspect ratio, submicron roughness is formed on the light emitting surface by transferring a thin film metal hard-mask having submicron patterns to the surface prior to applying a reactive ion etch process. The submicron patterns in the metal hard-mask can be formed using a low cost, commercially available nano-patterned template which is transferred to the surface with the mask. After subsequently binding the mask to the surface, the template is removed and the RIE process is applied for time duration sufficient to change the morphology of the surface. The modified surface contains non-symmetric, submicron structures having high aspect ratio which increase the efficiency of the device.

  10. Simulation of hurricane response to suppression of warm rain by sub-micron aerosols

    National Research Council Canada - National Science Library

    Rosenfeld, D; Khain, A; Lynn, B; Woodley, W. L

    2007-01-01

    ...). The possible impact of seeding of clouds with submicron cloud condensation nuclei (CCN) on hurricane structure and intensity as measured by nearly halving of the area covered by hurricane force winds was simulated by "turning...

  11. Study on the submicron and micron morphology and the properties of poor bituminous coal burnout

    Energy Technology Data Exchange (ETDEWEB)

    Pei-Fang Fu; Huai-Chun Zhou; Qing-Yan Fang; Hai Yao; Jianrong Qiu; Minghou Xu [Huazhong University of Science and Technology, Wuhan (China). State Key Laboratory of Coal Combustion

    2007-05-15

    Carbon burnout and its reaction mechanism have been widely focused on in the past decades. The properties of burnout, submicron and micron morphology and the reaction mechanism of poor bituminous coal/char (PBC) in a W-shaped power plant boiler was studied and was compared with those in DTF and in TGA, which showed that the degree of PBC burnout in TGA at 1450{sup o}C was greater than or approximately equal to that in a W-shaped boiler, and that the complexity of the reactions among residual char, oxygen and SiO{sub 2} did not seem to result in mass loss in TGA, although the weight percentage of the residual char in ash decreased from 33% ad (air dry basis) at 900{sup o}C to 9% and at 1450{sup o}C. According to the distribution of pores and the properties of the char burnout, the char can be simply categorized into three classes: char burnout easy, char burnout difficult and char burnout very difficult. The differences of the reaction mechanism must be considered while predicting the burning rate and degree of char burnout in a full-scale boiler by making use of experimental results from TGA and DTF. A different char particle contains markedly different amount of carbons, but for a special char particle, the ratio of carbon to ash is generally constant, and an ash shell does not exist on the char surface. The fusion mineral matter composing of C-O-Si-Al is amorphous, not in the form of Al{sub 2}O{sub 3} and SiO{sub 2} above 1450{sup o}C.

  12. Highly nonlinear sub-micron silicon nitride trench waveguide coated with gold nanoparticles

    Science.gov (United States)

    Huang, Yuewang; Zhao, Qiancheng; Sharac, Nicholas; Ragan, Regina; Boyraz, Ozdal

    2015-05-01

    We demonstrate the fabrication of a highly nonlinear sub-micron silicon nitride trench waveguide coated with gold nanoparticles for plasmonic enhancement. The average enhancement effect is evaluated by measuring the spectral broadening effect caused by self-phase-modulation. The nonlinear refractive index n2 was measured to be 7.0917×10-19 m2/W for a waveguide whose Wopen is 5 μm. Several waveguides at different locations on one wafer were measured in order to take the randomness of the nanoparticle distribution into consideration. The largest enhancement is measured to be as high as 10 times. Fabrication of this waveguide started with a MEMS grade photomask. By using conventional optical lithography, the wide linewidth was transferred to a wafer. Then the wafer was etched anisotropically by potassium hydroxide (KOH) to engrave trapezoidal trenches with an angle of 54.7º. Side wall roughness was mitigated by KOH etching and thermal oxidation that was used to generate a buffer layer for silicon nitride waveguide. The guiding material silicon nitride was then deposited by low pressure chemical vapor deposition. The waveguide was then patterned with a chemical template, with 20 nm gold particles being chemically attached to the functionalized poly(methyl methacrylate) domains. Since the particles attached only to the PMMA domains, they were confined to localized regions, therefore forcing the nanoparticles into clusters of various numbers and geometries. Experiments reveal that the waveguide has negligible nonlinear absorption loss, and its nonlinear refractive index can be greatly enhanced by gold nano clusters. The silicon nitride trench waveguide has large nonlinear refractive index, rendering itself promising for nonlinear applications.

  13. Envelope lipid-packing as a critical factor for the biological activity and stability of alphavirus particles isolated from mammalian and mosquito cells.

    Science.gov (United States)

    Sousa, Ivanildo P; Carvalho, Carlos A M; Ferreira, Davis F; Weissmüller, Gilberto; Rocha, Gustavo M; Silva, Jerson L; Gomes, Andre M O

    2011-01-21

    Alphaviruses are enveloped arboviruses. The viral envelope is derived from the host cell and is positioned between two icosahedral protein shells (T = 4). Because the viral envelope contains glycoproteins involved in cell recognition and entry, the integrity of the envelope is critical for the success of the early events of infection. Differing levels of cholesterol in different hosts leads to the production of alphaviruses with distinct levels of this sterol loaded in the envelope. Using Mayaro virus, a New World alphavirus, we investigated the role of cholesterol on the envelope of alphavirus particles assembled in either mammalian or mosquito cells. Our results show that although quite different in their cholesterol content, Mayaro virus particles obtained from both cells share a similar high level of lateral organization in their envelopes. This organization, as well as viral stability and infectivity, is severely compromised when cholesterol is depleted from the envelope of virus particles isolated from mammalian cells, but virus particles isolated from mosquito cells are relatively unaffected by cholesterol depletion. We suggest that it is not cholesterol itself, but rather the organization of the viral envelope, that is critical for the biological activity of alphaviruses.

  14. Carbon sources in suspended particles and surface sediments from the Beaufort Sea revealed by molecular lipid biomarkers and compound-specific isotope analysis

    Directory of Open Access Journals (Sweden)

    I. Tolosa

    2013-03-01

    Full Text Available Molecular lipid biomarkers (hydrocarbons, alcohols, sterols and fatty acids and compound-specific isotope analysis of suspended particulate organic matter (SPM and surface sediments of the Mackenzie Shelf and slope (southeast Beaufort Sea, Arctic Ocean were studied in summer 2009. The concentrations of the molecular lipid markers, characteristic of known organic matter sources, were grouped and used as proxies to evaluate the relative importance of fresh algal, detrital algal, fossil, C3 terrestrial plants, bacterial and zooplankton material in the organic matter (OM of this area. Fossil and detrital algal contributions were the major fractions of the freshwater SPM from the Mackenzie River with ~34% each of the total molecular biomarkers. Fresh algal, C3 terrestrial, bacterial and zooplanktonic components represented much lower percentages, 17, 10, 4 and 80%, with a minor contribution of fossil and C3 terrestrial biomarkers. Characterization of the sediments revealed a major sink of refractory algal material mixed with some fresh algal material, fossil hydrocarbons and a small input of C3 terrestrial sources. In particular, the sediments from the shelf and at the mouth of the Amundsen Gulf presented the highest contribution of detrital algal material (60–75%, whereas those from the slope contained the highest proportion of fossil (40% and C3 terrestrial plant material (10%. Overall, considering that the detrital algal material is marine derived, autochthonous sources contributed more than allochthonous sources to the OM lipid pool. Using the ratio of an allochthonous biomarker (normalized to total organic carbon, TOC found in the sediments to those measured at the river mouth water, we estimated that the fraction of terrestrial material preserved in the sediments accounted for 30–40% of the total carbon in the inner shelf sediments, 17% in the outer shelf and Amundsen Gulf and up to 25% in the slope sediments. These estimates are low

  15. Carbon sources in suspended particles and surface sediments from the Beaufort Sea revealed by molecular lipid biomarkers and compound-specific isotope analysis

    Science.gov (United States)

    Tolosa, I.; Fiorini, S.; Gasser, B.; Martín, J.; Miquel, J. C.

    2013-03-01

    Molecular lipid biomarkers (hydrocarbons, alcohols, sterols and fatty acids) and compound-specific isotope analysis of suspended particulate organic matter (SPM) and surface sediments of the Mackenzie Shelf and slope (southeast Beaufort Sea, Arctic Ocean) were studied in summer 2009. The concentrations of the molecular lipid markers, characteristic of known organic matter sources, were grouped and used as proxies to evaluate the relative importance of fresh algal, detrital algal, fossil, C3 terrestrial plants, bacterial and zooplankton material in the organic matter (OM) of this area. Fossil and detrital algal contributions were the major fractions of the freshwater SPM from the Mackenzie River with ~34% each of the total molecular biomarkers. Fresh algal, C3 terrestrial, bacterial and zooplanktonic components represented much lower percentages, 17, 10, 4 and 80%), with a minor contribution of fossil and C3 terrestrial biomarkers. Characterization of the sediments revealed a major sink of refractory algal material mixed with some fresh algal material, fossil hydrocarbons and a small input of C3 terrestrial sources. In particular, the sediments from the shelf and at the mouth of the Amundsen Gulf presented the highest contribution of detrital algal material (60-75%), whereas those from the slope contained the highest proportion of fossil (40%) and C3 terrestrial plant material (10%). Overall, considering that the detrital algal material is marine derived, autochthonous sources contributed more than allochthonous sources to the OM lipid pool. Using the ratio of an allochthonous biomarker (normalized to total organic carbon, TOC) found in the sediments to those measured at the river mouth water, we estimated that the fraction of terrestrial material preserved in the sediments accounted for 30-40% of the total carbon in the inner shelf sediments, 17% in the outer shelf and Amundsen Gulf and up to 25% in the slope sediments. These estimates are low compared to other

  16. Effects of Mg content on aging behavior of sub-micron Al2O3p/Al-Cu-Mg composites

    Institute of Scientific and Technical Information of China (English)

    JIANG Long-tao; ZHU De-zhi; CHEN Guo-qin; XIU Zi-yang; WU Gao-hui

    2006-01-01

    30%Al2O3p/Al-Cu-2.0Mg composite and Al2O3p/Al-Cu-2.5Mg composite with 0.3 μm-Al2O3 particles were fabricated.Age-hardening behaviors of two composites and the related matrix alloys were studied by means of Brinell-hardness measurement,DSC and TEM. The results show that the hardness of the composite is improved obviously because of the addition of sub-micron Al2O3 particles. But the hardness increment of Al2O3p/Al composite after aging is lower than that of the related matrix alloy.Moreover, the formation of GP region is suppressed by the addition of sub-micron Al2O3 particles, which broadens the exothermic peak of S' phase. The increment of Mg content has a different influence on accelerating the aging processes of aluminum alloys and the composites, and the hardness also increases.

  17. Controlled motion of domain walls in submicron amorphous wires

    Directory of Open Access Journals (Sweden)

    Mihai Ţibu

    2016-05-01

    Full Text Available Results on the control of the domain wall displacement in cylindrical Fe77.5Si7.5B15 amorphous glass-coated submicron wires prepared by rapid quenching from the melt are reported. The control methods have relied on conical notches with various depths, up to a few tens of nm, made in the glass coating and in the metallic nucleus using a focused ion beam (FIB system, and on the use of small nucleation coils at one of the sample ends in order to apply magnetic field pulses aimed to enhance the nucleation of reverse domains. The notch-based method is used for the first time in the case of cylindrical ultrathin wires. The results show that the most efficient technique of controlling the domain wall motion in this type of samples is the simultaneous use of notches and nucleation coils. Their effect depends on wire diameter, notch depth, its position on the wire length, and characteristics of the applied pulse.

  18. NMOS symmetric load ring VCOs modeling for submicron technologies

    Science.gov (United States)

    Fino, M. Helena

    2005-06-01

    Voltage Controlled Oscillators (VCOs) are a key element in PLL design. The simulation of VCOs is a time consuming process because transient circuit simulations must run long enough that the steady state is attained. Furthermore, the robustness of design against operating and technological conditions must also be tested by simulating the circuits at several corners, thus making the design methodology based in iterative simulation rather prohibitive for this class of circuits. The development of efficient and reliable VCO models is therefore a very important task, not only for the automation of the circuit design, but for design space exploration as well. Besides accuracy and simplicity, models must easily adapt to the rapid technology evolution. In order to grant such robustness, we must develop models based on transistor level technological parameters. This paper presents an accurate model for submicron Voltage Controlled Oscillators (VCOs). The model obtained is based on the Npower MOS model, yielding quite accurate results for sub micron technologies. An example considering a 1.2V TSMC013 VCO is presented, where the accuracy of the results obtained against Hspice simulation is shown. Results obtained in about 2 seconds have 4% average error, compared to simulations taking over 15 minutes.

  19. An X-Ray Tomographic Microscope with Submicron Resolution

    Science.gov (United States)

    Stampanoni, M.; Borchert, G. L.; Abela, R.; Patterson, B.; Vermeulen, D.; Rueegsegger, P.; Wyss, P.

    2002-01-01

    X-ray tomographic microscopy (XTM) is a powerful non-destructive investigation method, that has been applied in many fields of modern research (material science, microelectronics, medicine, biology, archaeology). Sofar the major limitations were imposed by low detection efficiency and low spatial resolution. With the advent of third generation synchrotron facilities excellent high intensity X-ray sources became available that by far counterbalanced low efficiency. On the other hand the resolution of presently used detector systems is restricted by scintillator properties, optical light transfer, and CCD granularity. They impose a practical limit of about one micrometer, while the progressing research demands urgently an advance in the submicron region. A break-through in this respect is being achieved by a novel detector type. It uses the properties of asymmetric Bragg reflection to increase the cross section of the reflected X-ray beam. A suitable combination of correspondingly cut Bragg crystals yields an image magnification that even at higher energies may surpass a factor of 1000. In this way the influence of the detector resolution can be scaled down accordingly. Such a device is being constructed and installed at the SLS which delivers an optimal X-ray beam of about 23 keV. The special properties of this experiment will be presented.

  20. Dynamics of Red Blood Cells through submicronic splenic slits

    Science.gov (United States)

    Helfer, Emmanuele; Gambhire, Priya; Atwell, Scott; Bedu, Frederic; Ozerov, Igor; Viallat, Annie; Charrier, Anne; Badens, Catherine; Centre de reference Thalassemie, Badens Team; Physics; Engineering of Living Systems Team

    2016-11-01

    Red Blood Cells (RBCs) are periodically monitored for changes in their deformability by the spleen, and are entrapped and destroyed if unable to pass through the splenic interendothelial slits (IESs). In particular, in sickle cell disease (SCD), where hemoglobin form fibers inside the RBCs, and in hereditary spherocytosis (HS), where RBCs are more spherical and membrane-cytoskekeleton bonds are weakened, the loss of RBC deformability leads to spleen dysfunction. By combining photolithography and anisotropic wet etching techniques, we developed a new on-chip PDMS device with channels replicating the submicronic physiological dimensions of IESs to study the mechanisms of deformation of the RBCs during their passage through these biomimetic slits. For the first time, with HS RBCs, we show the disruption of the links between the RBC membrane and the underlying spectrin network. In the case of SCD RBCs we show the appearance of a tip at the front of the RBC with a longer time relaxation due to the increased cytoplasmic viscosity. This work has been carried out thanks to the support of the A*MIDEX project (n° ANR-11-IDEX-0001-02) funded by the «Investissements d'Avenir». French Government program, managed by ANR.

  1. Resolution enhancement techniques for submicron deep trench processes

    Science.gov (United States)

    Tong, Lijun; Hsiang, Joyce; Lin, Kuanchih; Newman, Gary

    1999-08-01

    Due to the rapid advancements in the data storage market, the development of new technologies and mechanisms are needed to support the continued growth of data storage systems. The concept and technology of Micro Electro Mechanical Systems (MEMS) can provide opportunities to meet these demands. Correspondingly, new MEMS devices can be made commercially available by sharing the benefits of developments in data storage systems. The photolithography requirements for thin film head (TFH) processing have grown increasingly challenging. Specifically, the resolution of submicron isolated features is required in thick photoresist; resulting in aspect ratios of nearly 10 to 1. To satisfy these imaging requirements, the use of i-line reduction lithography tools with variable numerical aperture and partial coherence are necessary. This study examines the influence of NA, (sigma) , and reticle bias on critical features in a typical TFH write-layer process. Combinations of NA and (sigma) were investigated for their impact on minimum feature size, process latitude, and sidewall angle. Process latitude was quantified for each illumination condition over a range of focus and exposure conditions.

  2. 液态氟碳脂质微球靶向损伤心肌细胞的体外实验%In Vitro Experimental Study of Rat Cardiomyocyte Injury with Targeting of Perfluorocarbon Lipid Particles

    Institute of Scientific and Technical Information of China (English)

    何佰永; 李赵欢; 唐红; 李国华; 陈松; 王炼; 宋海波; 方华; 曾俊

    2011-01-01

    The present study was to investigate in vitro the rat cardiomyocyte injury with targeting of home-made per-fluorocarbon lipid particles with avidin-biotin interaction. Neonatal rat cardiomyocytes were cultured in vitro and divided into two groups: TNF-a activated group and non-activated group. Those in the TNF-α activated group were exposed to 200ng/ml TNF-a solution for 6 hours and then cardiomyocytes in both groups were pretargeted with bioti-nylated ICAM-1 monoclonal antibodies, and were exposed to streptavidin, and then to home-made green fluorescent-ly-labeled biotinylated perfluorocarbon lipid particles. Cardiomyocytes nucleus stained with Hoechst. The results were detected with fluorescence microscope. As a result, in TNF-a activated group, around blue fluorescent cardiomyocytes nucleus, a great amount of green fluorescent particles were found, while there were few green fluorescent particles in non-TNF activated group. It has been shown that ICAM-1 is expressed in the surface of cardiomyocytes when they are stimulated by TNF-a. Perfluorocarbon lipid particles associated with ICAM-1 monoclonal antibodies can be targeted to injured cardiomyocytes by avidin-biotin interaction.%采用生物素-亲和素作用实现自制液态氟碳脂质微球与损伤后心肌细胞的靶向结合.先体外培养大鼠原代心肌细胞,将培养出的心肌细胞分为TNF-α处理组和非处理组,TNF-α处理组的心肌细胞给予200 ng/ml TNF-α溶液刺激.6h后两组均先后加入等量的生物素化的抗大鼠细胞间黏附分子-1(ICAM-1)单克隆抗体、链酶亲和素和自制生物素化液态氟碳脂质微球,然后用Hoechst液对两组心肌细胞核染色,最后在荧光显微镜下观察.结果显示TNF-α处理组染成蓝色的心肌细胞核周围可见大量绿色荧光微球,但非处理组蓝色的心肌细胞核周围有极少许绿色荧光微球.研究表明心肌细胞在TNF-α刺激下可产生ICAM-1炎症细胞因子,液

  3. Lipid domains control myelin basic protein adsorption and membrane interactions between model myelin lipid bilayers.

    Science.gov (United States)

    Lee, Dong Woog; Banquy, Xavier; Kristiansen, Kai; Kaufman, Yair; Boggs, Joan M; Israelachvili, Jacob N

    2014-02-25

    The surface forces apparatus and atomic force microscope were used to study the effects of lipid composition and concentrations of myelin basic protein (MBP) on the structure of model lipid bilayers, as well as the interaction forces and adhesion between them. The lipid bilayers had a lipid composition characteristic of the cytoplasmic leaflets of myelin from "normal" (healthy) and "disease-like" [experimental allergic encephalomyelitis (EAE)] animals. They showed significant differences in the adsorption mechanism of MBP. MBP adsorbs on normal bilayers to form a compact film (3-4 nm) with strong intermembrane adhesion (∼0.36 mJ/m(2)), in contrast to its formation of thicker (7-8 nm) swelled films with weaker intermembrane adhesion (∼0.13 mJ/m(2)) on EAE bilayers. MBP preferentially adsorbs to liquid-disordered submicron domains within the lipid membranes, attributed to hydrophobic attractions. These results show a direct connection between the lipid composition of membranes and membrane-protein adsorption mechanisms that affects intermembrane spacing and adhesion and has direct implications for demyelinating diseases.

  4. Formation of submicron magnesite during reaction of natural forsterite in H2O-saturated supercritical CO2

    Science.gov (United States)

    Qafoku, Odeta; Hu, Jianzhi; Hess, Nancy J.; Hu, Mary Y.; Ilton, Eugene S.; Feng, Ju; Arey, Bruce W.; Felmy, Andrew R.

    2014-06-01

    Natural forsterite was reacted in bulk liquid water saturated with supercritical CO2 (scCO2) and scCO2 saturated with water at 35-80 °C and 90 atm. The solid reaction products were analyzed with nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), and confocal Raman spectroscopy. Two carbonate phases, nesquehonite (MgCO3·3H2O) and magnesite (MgCO3), were identified with the proportions of the two phases depending on experimental conditions. In liquid water saturated with scCO2, nesquehonite was the dominant carbonate phase at 35-80 °C with only a limited number of large, micron size magnesite particles forming at the highest temperature, 80 °C. In contrast, in scCO2 saturated with H2O magnesite formation was identified at all three temperatures: 35, 50, and 80 °C. Magnesite was the dominant carbonation reaction product at 50 and 80 °C, but nesquehonite was dominant at 35 °C. The magnesite particles formed under scCO2 saturated with H2O conditions exhibited an extremely uniform submicron grain-size and nearly identical rhombohedral morphologies at all temperatures. The distribution and form of the particles were not consistent with nucleation and growth on the forsterite surface.

  5. Formation of Submicron Magnesite during Reaction of Natural Forsterite in H2O-Saturated Supercritical CO2

    Energy Technology Data Exchange (ETDEWEB)

    Qafoku, Odeta; Hu, Jian Z.; Hess, Nancy J.; Hu, Mary Y.; Ilton, Eugene S.; Feng, Ju; Arey, Bruce W.; Felmy, Andrew R.

    2014-06-01

    Natural forsterite was reacted in a) liquid water saturated with supercritical CO2 (scCO2) and in b) H2O-saturated scCO2 at 35-80 °C and 90 atm. The solid reaction products were analyzed with nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), and confocal Raman spectroscopy. Two carbonate phases, nesquehonite (MgCO3.3H2O) and magnesite (MgCO3), were identified with the proportions of the two phases depending on experimental conditions. In water saturated with scCO2, nesquehonite was the dominant carbonate phase at 35-80 °C with only a limited number of large, micron size magnesite particles forming at the highest temperature, 80 °C. In contrast, in H2O-saturated scCO2 magnesite formation was identified at all three temperatures: 35 °, 50 °, and 80 °C. Magnesite was the dominant carbonation reaction product at 50 ° and 80 °C; but nesquehonite was dominant at 35 °C. The magnesite particles formed under H2O-saturated scCO2 conditions exhibited an extremely uniform submicron grain-size and nearly identical rhombohedral morphologies at all temperatures. The distribution and form of the particles were not consistent with epitaxial nucleation and growth on the forsterite surface.

  6. Sub-micron parallel laser direct-write

    Science.gov (United States)

    Othon, Christina M.; Laracuente, Arnaldo; Ladouceur, H. D.; Ringeisen, Bradley R.

    2008-12-01

    We have developed a modified laser induced forward transfer (LIFT) technique which allows for the parallel deposition of hundreds of sub-micron features. The approach utilizes a self-assembled monolayer of monodisperse polystyrene microspheres as the focusing element. A monolayer of close-packed microspheres is formed on top of an ultra-thin quartz support (25 μm thick), and a metallic thin film is then deposited on the underside of the quartz. This approach is different from previous parallel microsphere-assisted LIFT experiments that required the deposition of metal directly onto the surface of the periodic microsphere structure. For this study, an 800 nm, 130 fs laser pulse was directed toward the microsphere layer to focus the incident laser beam through the thin quartz layer to the quartz-metal interface. At this interface, a portion of the thin metal film was ablated directly below each microsphere, resulting in an array of holes in the thin metal film. The metal removed from the film was patterned onto a receiving substrate to form an array of discrete deposits. In some cases, a two layer thin film was utilized resulting in the forward transfer of bilayer metal features. The holes and deposited features were characterized using scanning electron microscopy, atomic force microscopy, and scanning Auger electron spectroscopy. The diameter of the holes (0.5-5 μm) as well as the diameter (0.9-5 μm) and quality of the deposited metallic features were modulated by varying the sphere size, incident laser energy, and material composition.

  7. Submicron hard X-ray fluorescence imaging of synthetic elements

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, Mark P., E-mail: mjensen@anl.gov [Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Aryal, Baikuntha P. [Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Department of Chemistry, University of Chicago, Chicago, IL 60637 (United States); Gorman-Lewis, Drew [Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Paunesku, Tatjana [Department of Radiation Oncology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611 (United States); Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611 (United States); Lai, Barry; Vogt, Stefan [X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439 (United States); Woloschak, Gayle E. [Department of Radiation Oncology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611 (United States); Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611 (United States)

    2012-04-13

    Highlights: Black-Right-Pointing-Pointer Actinide elements are mapped with L-edge X-rays and better than 400 nm resolution. Black-Right-Pointing-Pointer A typical detection limit was 2.9 Multiplication-Sign 10{sup -20} moles Pu {mu}m{sup -2}. Black-Right-Pointing-Pointer XANES measurements provide chemical information in 0.1 {mu}m{sup 2} spots. Black-Right-Pointing-Pointer Selection of materials for encapsulation is important for avoiding interferences. - Abstract: Synchrotron-based X-ray fluorescence microscopy (XFM) using hard X-rays focused into sub-micron spots is a powerful technique for elemental quantification and mapping, as well as microspectroscopic measurements such as {mu}-XANES (X-ray absorption near edge structure). We have used XFM to image and simultaneously quantify the transuranic element plutonium at the L{sub 3} or L{sub 2}-edge as well as Th and lighter biologically essential elements in individual rat pheochromocytoma (PC12) cells after exposure to the long-lived plutonium isotope {sup 242}Pu. Elemental maps demonstrate that plutonium localizes principally in the cytoplasm of the cells and avoids the cell nucleus, which is marked by the highest concentrations of phosphorus and zinc, under the conditions of our experiments. The minimum detection limit under typical acquisition conditions with an incident X-ray energy of 18 keV for an average 202 {mu}m{sup 2} cell is 1.4 fg Pu or 2.9 Multiplication-Sign 10{sup -20} moles Pu {mu}m{sup -2}, which is similar to the detection limit of K-edge XFM of transition metals at 10 keV. Copper electron microscopy grids were used to avoid interference from gold X-ray emissions, but traces of strontium present in naturally occurring calcium can still interfere with plutonium detection using its L{sub {alpha}} X-ray emission.

  8. Aligned submicron grains in archeological potteries with high TRM anisotropy

    Science.gov (United States)

    Fukuma, K.; Ooga, M.; Isobe, H.

    2010-12-01

    Potteries have been often used to obtain archeointensity data because of the extremely high success rates in Thellier experiments. Since high anisotropy of thermoremanent magnetization (TRM) are commonly observed for potteries, anisotropy correction is routinely applied to make archeointensity data reliable. Such a TRM anisotropy is characterized by the foliated structure parallel to the surface and has been interpreted to reflect aligned magnetic minerals during molding. However, the high thermal stability and the higher degrees of TRM anisotropies than those of low-field susceptibility suggest that pottery TRM resides in fine-grained magnetic minerals formed during firing. Molding is not sufficient to explain highly anisotropic TRM of potteries. We measured TRM susceptibility tensors on potteries manufactured from 14th to 17th centuries in Japan. These potteries were fired up to about 1200°C resulting in partial vitrification. The ratios of maximum and minimum eigenvalues of the TRM susceptibility tensors are well distributed and reaches 1.8 for most anisotropic samples. The Curie temperature ranges from 500°C to 550°C implying titanium-poor titanomagnetite as TRM carriers, and the narrow unblocking temperature indicates that the low-titanium titanomagnetites are in or close to the single-domain size range. Submicron titanomagnetite grains were commonly observed on the polished sections under a FE-SEM. Some of the grains occur as inclusions in iron-bearing silicates such as pyroxene or hornblende, and other grains reside in glass matrix. In addition, vesiculated clay minerals contain highly elongated titanomagnetite grains. Such clay minerals seem stretched parallel to the pottery surface and inside titanomagnetite grains are also elongated along the surface. Relative abundance of titanomagnetite inclusions in silicates or glass against in clay minerals should control the degree of TRM anisotropy. Foliated TRM anisotropies originate from both alignment of clay

  9. Dust Diffusion and Settling in the Presence of Collisions: Trapping (sub)micron Grains in the Midplane

    Science.gov (United States)

    Krijt, Sebastiaan; Ciesla, Fred J.

    2016-05-01

    In protoplanetary disks, the distribution and abundance of small (sub)micron grains are important for a range of physical and chemical processes. For example, they dominate the optical depth at short wavelengths and their surfaces are the sites of many important chemical reactions, such as the formation of water. Based on their aerodynamical properties (i.e., their strong dynamical coupling with the surrounding gas) it is often assumed that these small grains are well-mixed with the gas. Our goal is to study the vertical (re)distribution of grains taking into account settling, turbulent diffusion, and collisions with other dust grains. Assuming a fragmentation-limited background dust population, we developed a Monte Carlo approach that follows single monomers as they move through a vertical column of gas and become incorporated in different aggregates as they undergo sticking and fragmenting collisions. We find that (sub)micron grains are not necessarily well-mixed vertically, but can become trapped in a thin layer with a scale height that is significantly smaller than that of the gas. This collisional trapping occurs when the timescale for diffusion is comparable to or longer than the collision timescale in the midplane and its effect is strongest when the most massive particles in the size distribution show significant settling. Based on simulations and analytical considerations, we conclude that for typical dust-to-gas ratios and turbulence levels, the collisional trapping of small grains should be a relatively common phenomenon. The absence of trapping could then indicate a low dust-to-gas ratio, possibly because a large portion of the dust mass has been removed through radial drift or is locked up in planetesimals.

  10. Vertical distribution of sub-micron aerosol chemical composition from North-Western Europe and the North-East Atlantic

    Directory of Open Access Journals (Sweden)

    W. T. Morgan

    2009-08-01

    Full Text Available A synthesis of UK based airborne in-situ measurements of aerosol properties representing air masses from North-West Europe and the North-East Atlantic is presented. The major focus of the study is the vertical distribution of sub-micron aerosol chemical composition. Vertical profiles are derived from a Quadrupole Aerosol Mass Spectrometer (Q-AMS. Background sub-micron aerosol vertical profiles are identified and are primarily composed of organic matter and sulphate aerosol. Such background conditions occurred predominantly during periods associated with long-range air mass transport across the Atlantic. These instances may serve as useful model input of aerosol to Western Europe. Increased mass concentration episodes are coincident with European outflow and periods of stagnant/recirculating air masses. Such periods are characterised by significantly enhanced concentrations of nitrate aerosol relative to those of organic matter and sulphate. Periods of enhanced ground level PM2.5 loadings are coincident with instances of high nitrate mass fractions measured on-board the aircraft, indicating that nitrate is a significant contributor to regional pollution episodes. The vertical structure of the sulphate and organic aerosol profiles were shown to be primarily driven by large-scale dynamical processes. The vertical distribution of nitrate is likely determined by both dynamic and thermodynamic processes, with chemical partitioning of gas phase precursors to the particle phase occurring at lower temperatures at the top of the boundary layer. Such effects have profound implications for the aerosol's lifetime and subsequent impacts, highlighting the requirement for accurate representation of the aerosol vertical distribution.

  11. A statistical analysis of North East Atlantic (submicron) aerosol size distributions

    Science.gov (United States)

    Dall'Osto, M.; Monahan, C.; Greaney, R.; Beddows, D. C. S.; Harrison, R. M.; Ceburnis, D.; O'Dowd, C. D.

    2011-12-01

    The Global Atmospheric Watch research station at Mace Head (Ireland) offers the possibility to sample some of the cleanest air masses being imported into Europe as well as some of the most polluted being exported out of Europe. We present a statistical cluster analysis of the physical characteristics of aerosol size distributions in air ranging from the cleanest to the most polluted for the year 2008. Data coverage achieved was 75% throughout the year. By applying the Hartigan-Wong k-Means method, 12 clusters were identified as systematically occurring. These 12 clusters could be further combined into 4 categories with similar characteristics, namely: coastal nucleation category (occurring 21.3 % of the time), open ocean nucleation category (occurring 32.6% of the time), background clean marine category (occurring 26.1% of the time) and anthropogenic category (occurring 20% of the time) aerosol size distributions. The coastal nucleation category is characterised by a clear and dominant nucleation mode at sizes less than 10 nm while the open ocean nucleation category is characterised by a dominant Aitken mode between 15 nm and 50 nm. The background clean marine aerosol exhibited a clear bimodality in the sub-micron size distribution, with although it should be noted that either the Aitken mode or the accumulation mode may dominate the number concentration. However, peculiar background clean marine size distributions with coarser accumulation modes are also observed during winter months. By contrast, the continentally-influenced size distributions are generally more monomodal (accumulation), albeit with traces of bimodality. The open ocean category occurs more often during May, June and July, corresponding with the North East (NE) Atlantic high biological period. Combined with the relatively high percentage frequency of occurrence (32.6%), this suggests that the marine biota is an important source of new nano aerosol particles in NE Atlantic Air.

  12. A statistical analysis of North East Atlantic (submicron aerosol size distributions

    Directory of Open Access Journals (Sweden)

    M. Dall'Osto

    2011-12-01

    Full Text Available The Global Atmospheric Watch research station at Mace Head (Ireland offers the possibility to sample some of the cleanest air masses being imported into Europe as well as some of the most polluted being exported out of Europe. We present a statistical cluster analysis of the physical characteristics of aerosol size distributions in air ranging from the cleanest to the most polluted for the year 2008. Data coverage achieved was 75% throughout the year. By applying the Hartigan-Wong k-Means method, 12 clusters were identified as systematically occurring. These 12 clusters could be further combined into 4 categories with similar characteristics, namely: coastal nucleation category (occurring 21.3 % of the time, open ocean nucleation category (occurring 32.6% of the time, background clean marine category (occurring 26.1% of the time and anthropogenic category (occurring 20% of the time aerosol size distributions. The coastal nucleation category is characterised by a clear and dominant nucleation mode at sizes less than 10 nm while the open ocean nucleation category is characterised by a dominant Aitken mode between 15 nm and 50 nm. The background clean marine aerosol exhibited a clear bimodality in the sub-micron size distribution, with although it should be noted that either the Aitken mode or the accumulation mode may dominate the number concentration. However, peculiar background clean marine size distributions with coarser accumulation modes are also observed during winter months. By contrast, the continentally-influenced size distributions are generally more monomodal (accumulation, albeit with traces of bimodality. The open ocean category occurs more often during May, June and July, corresponding with the North East (NE Atlantic high biological period. Combined with the relatively high percentage frequency of occurrence (32.6%, this suggests that the marine biota is an important source of new nano aerosol particles in NE Atlantic Air.

  13. Electrical immunosensor based on a submicron-gap interdigitated electrode and gold enhancement.

    Science.gov (United States)

    Ahn, Junhyoung; Lee, Tae Han; Li, Taihua; Heo, Kwang; Hong, Seunghun; Ko, Jeongheon; Kim, Yongsam; Shin, Yong-Beom; Kim, Min-Gon

    2011-08-15

    We demonstrated that the detection of human interleukin 5 (IL5) with a higher sensitivity than the enzyme-linked immunosorbent assay (ELISA) was possible using mass-producible submicron-gap interdigitated electrodes (IDEs) combined with signal amplification by a gold nanoparticle (AuNP) and gold enhancement. IDEs, facing comb-shape electrodes, can act as simple and miniaturized devices for immunoassay. An IDE with a gap size of 400nm was fabricated by a stepper photolithography process and was applied for the immunoassay of human IL5. A biotinylated anti-human IL5 was immobilized on the streptavidin-modified IDE, and biotin-bovine serum albumin (BSA) and BSA were added sequentially to reduce non-specific binding between the streptavidin-immobilized IDE surface and other proteins. The immunoassay procedure included three main steps: the reaction of human IL5 to form antigen-antibody complexes, the binding of AuNP conjugation with an antibody against human IL5 for the sandwich immunoassay, and gold enhancement for electrical signal amplification. The measurement of electrical current at each step showed that the gold enhancement step was very critical in detection of the concentration of human IL5. Analysis by scanning electron microscope (SEM) showed that close to 1μm particles were formed from 10nm AuNP by the gold enhancement reaction using gold ions and hydroxylamine. Under optimized conditions, human IL5 could be analyzed at 1pgmL(-1) with a wide dynamic range (from 10(-3) to 100ngmL(-1) concentrations).

  14. Pharmacokinetics of a novel submicron budesonide dispersion for nebulized delivery in asthma.

    Science.gov (United States)

    Shrewsbury, Stephen B; Bosco, Andrew P; Uster, Paul S

    2009-01-01

    The objective of this study was to evaluate the safety and pharmacokinetics of unit dose budesonide (UDB), an aqueous dispersion of submicron-sized budesonide particles, and a commercially available budesonide suspension formulation. This was a randomized, double-blind, active-controlled, 4-period, 4-way crossover trial in 16 healthy, adult volunteers. Subjects received UDB 0.24, 0.12, and 0.06 mg or commercial budesonide 0.25 mg via a jet nebulizer. T(max) was significantly (p<0.05) earlier for UDB 0.06, 0.12, and 0.24 mg (4.5+/-3.3, 3.1+/-1.5, 3.7+/-1.5 min) vs. commercial budesonide (9.1+/-7.1 min). C(max) was significantly (p<0.05) higher for UDB 0.24 mg vs. commercial budesonide 0.25 mg (434.5+/-246.9 pg/mL vs. 303.5+/-177.4 pg/mL) but not between UDB 0.12 mg (239.9+/-140 pg/mL) and commercial budesonide 0.25 mg (p=0.448). AUC(0-infinity) was marginally, but significantly lower for UDB 0.24 mg than commercial budesonide 0.25 mg. AUCs for UDB 0.12 mg were lower than commercial budesonide 0.25 mg. UDB 0.24 mg was absorbed more rapidly and achieved higher peak concentrations than commercial budesonide 0.25 mg, but had a lower AUC(0-infinity). UDB 0.12 mg also was absorbed more rapidly but had lower C(max) and AUCs than commercial budesonide 0.25 mg.

  15. Chemical characterization of submicron particles during typical air pollution episodes in spring over Beijing

    National Research Council Canada - National Science Library

    YANG Ting SUN Ye-Le ZHANG Wei WANG Zi-Fa WANG Xi-Quan

    2016-01-01

    Beijing experienced a long-lasting pollution episode in April 2012. Here, the authors characterize the sources and evolution processes of the pollution, with a focus on a haze and a dust episode that occurred during 15-30 April...

  16. Process Intensification in Crystallization: Submicron Particle Generation Using Alternative Energy Forms

    NARCIS (Netherlands)

    Radacsi, N.

    2012-01-01

    Crystallization is one of the oldest separation and product formation techniques that continues to be in use today. Despite its long history, it only started to develop significantly in the past few decades. In this thesis, the application of Process Intensification in crystallization is

  17. Process Intensification in Crystallization: Submicron Particle Generation Using Alternative Energy Forms

    NARCIS (Netherlands)

    Radacsi, N.

    2012-01-01

    Crystallization is one of the oldest separation and product formation techniques that continues to be in use today. Despite its long history, it only started to develop significantly in the past few decades. In this thesis, the application of Process Intensification in crystallization is investigate

  18. Distribution of neutral lipids in the lipid droplet core

    DEFF Research Database (Denmark)

    Chaban, Vitaly V; Khandelia, Himanshu

    2014-01-01

    Cholesteryl esters (CEs) are a form of cholesterol (CHOL) storage in the living cells, as opposed to free CHOL. CEs are major constituents of low density lipoprotein particles. Therefore, CEs are implicated in provoking atherosclerosis. Arranged into cytoplasmic lipid droplets (LDs), CEs are stored...

  19. Submicron aerosol size distribution measurements in the city of Seoul, and coastal and marine environments around South Korea

    Science.gov (United States)

    Yum, S. S.; Kim, J.; Han, D.; Oh, S.; Nam, J.

    2005-12-01

    Submicron aerosol size distributions and total particle (i.e., condensation nuclei, CN) concentrations were measured continuously from September 2004 at the campus of Yonsei University located at the central part of Seoul. The instruments, TSI SMPS-3936L10 and CPC-3010, were installed at an office in the sixth floor of a building and the sample air was drawn from a window. The height of the building and the relatively low traffic in the campus may qualify these measurements as a background aerosol distribution in a highly urbanized city. The highest monthly average CPC (total particle) concentration was 37000 cm-3 in February 2005. The trend of wintertime increase was also obvious in the SMPS integrated concentrations but these were only 60-70 percent of the CPC concentrations. There was rather clear diurnal trend of near dawn (~4 AM) minima and morning peak (~8 AM) and a secondary peak in the evening (~8 PM) for both CPC and SMPS data. As a part of the Atmospheric Brown Clouds East Asian Regional Experiment (ABC-EAREX2005), measurements were also made on board the research vessel Kisang 2000 during the cruise from March 2 to March 10, 2005 over the South Sea of Korea and over the Korean sector of the Yellow Sea. Ship track was 60 km or more away from the coast. After the ship measurements the instruments were placed at the Gosan ABC Observatory in Jeju Island, for almost four weeks starting from March 11, 2005 to measure coastal aerosol distributions and inter-comparisons with other instruments. The average CPC and SMPS concentrations were 6700 cm-3 and 4400 cm-3, respectively, for the ship measurements, and 6000 cm-3 and 4000 cm-3 for the same two measurements at Gosan. However, when remote marine environments near Jeju Island were segregated from the ship measurements, the CPC and SMPS concentrations were 3600 cm-3 and 2400 cm-3, respectively. CPC and SMPS measurements will also be made over the South China Sea during another ship cruise from Jeju Island to

  20. Fabrication and characterization of submicron polymer waveguides by micro-transfer molding

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Te-Wei [Iowa State Univ., Ames, IA (United States)

    2009-01-01

    Various methods exist for fabrication of micron and submicron sized waveguide structures. However, most of them include expensive and time consuming semiconductor fabrication techniques. An economical method for fabricating waveguide structures is introduced and demonstrated in this thesis. This method is established based on previously well-developed photonic crystal fabrication method called two-polymer microtransfer molding. The waveguide in this work functions by a coupler structure that diffracts the incident light into submicron polymer rods. The light is then guided through the rods. Characterization is done by collecting the light that has been guided through the waveguide and exits the end of these submicron polymer bars. The coupling and waveguiding capabilities are demonstrated using two light sources, a laser and white light.

  1. Microscopic Characterization of Individual Submicron Bubbles during the Layer-by-Layer Deposition: Towards Creating Smart Agents

    Directory of Open Access Journals (Sweden)

    Riku Kato

    2015-07-01

    Full Text Available We investigated the individual properties of various polyion-coated bubbles with a mean diameter ranging from 300 to 500 nm. Dark field microscopy allows one to track the individual particles of the submicron bubbles (SBs encapsulated by the layer-by-layer (LbL deposition of cationic and anionic polyelectrolytes (PEs. Our focus is on the two-step charge reversals of PE-SB complexes: the first is a reversal from negatively charged bare SBs with no PEs added to positive SBs encapsulated by polycations (monolayer deposition, and the second is overcharging into negatively charged PE-SB complexes due to the subsequent addition of polyanions (double-layer deposition. The details of these phenomena have been clarified through the analysis of a number of trajectories of various PE-SB complexes that experience either Brownian motion or electrophoresis. The contrasted results obtained from the analysis were as follows: an amount in excess of the stoichiometric ratio of the cationic polymers was required for the first charge-reversal, whereas the stoichiometric addition of the polyanions lead to the electrical neutralization of the PE-SB complex particles. The recovery of the stoichiometry in the double-layer deposition paves the way for fabricating multi-layered SBs encapsulated solely with anionic and cationic PEs, which provides a simple protocol to create smart agents for either drug delivery or ultrasound contrast imaging.

  2. THREE-DIMENSIONAL ANALYSIS OF SCALE DEPENDENCE OF SUB-MICRON POLYCRYSTALS DUE TO CONFIGURATION ENTROPY

    Institute of Scientific and Technical Information of China (English)

    杨强; 杨卫

    2001-01-01

    The authors proposed a plausible explanation for the deviation of experimental data for sub-micron polycrystals from the Hall-Petch relation by in troducing the configuration entropy. The present paper extends the previous two dimensional analysis to the three-dimensional case. The statistical distribution of dislocation lengths within a spherical grain and the bow-out of dislocations are con sidered. According to Ashby's model, analyses are pursued for the statistically stored dislocations and geometrically necessary dislocations, respectively. It is confirmed that the configuration entropy model can predict the abnormal Hall-Petch depen dence for grain sizes in the sub-micron range.

  3. Laser and Particle Guiding Micro-Elements for Particle Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Plettner, T.; Gaume, R.; Wisdom, J.; /Stanford U., Phys. Dept.; Spencer, J.; /SLAC

    2005-06-07

    Laser driven particle accelerators require sub-micron control of the laser field as well as precise electron-beam guiding so fabrication techniques that allow integrating both elements into an accelerator-on-chip format become critical for the success of such next generation machines. Micromachining technology for silicon has been shown to be one such feasible technology in PAC2003[1] but with a variety of complications on the laser side. However, fabrication of transparent ceramics has become an interesting technology that could be applied for laser-particle accelerators in several ways. We discuss the advantages such as the range of materials available and ways to implement them followed by some different test examples we been considered. One important goal is an integrated system that avoids having to inject either laser or particle pulses into these structures.

  4. Submicron mineral structures control the stabilization of litter-derived organic matter in soils - A NanoSIMS study

    Science.gov (United States)

    Vogel, Cordula; Mueller, Carsten W.; Höschen, Carmen; Buegger, Franz; Heister, Katja; Schulz, Stefanie; Schloter, Michael; Kögel-Knabner, Ingrid

    2014-05-01

    The sequestration of carbon and nitrogen by clay-sized particles in soils is well established. However, in the most cases, the complex structure of the organo-mineral associations remain a black box due to the common measurements of soil fractions as a whole. By combining nano-scale secondary ion mass spectrometry (NanoSIMS) with isotopic tracing it is possible to study the formation and spatial heterogeneity of organo-mineral associations. NanoSIMS enables the detection of up to seven secondary ion species (e.g. 13C-, 12N15N-, 27Al16O-, 56Fe16O-) simultaneously, to generate a submicron-scale image of the elemental and isotopic composition (e.g. 13C, 15N, Al and Fe) down to a lateral resolution of ~150 nm. Therefore this technique can be used to study organo-mineral associations at the relevant scale. The aim of our study was to follow the formation of organo-mineral associations over different time steps and the distribution of C and N by imaging the complex arrangement between soil mineral surfaces and litter-derived organic matter (OM). Parallel to the determination of the isotopic N and C composition of bulk soil and soil fractions (combined density and particle size fractionation) using isotope ratio mass spectrometry (IRMS), the spatial distribution of the OM was investigated by NanoSIMS analysis of the clay-sized fraction. In our study we show that only some of the clay-sized surfaces bind OM. Surprisingly, less than 19% of the mineral areas visible by scanning electron microscopy and NanoSIMS show an OM attachment. We demonstrate that mineral clusters with rough surfaces exhibit the preferential binding spots for OM. By combining NanoSIMS and isotopic tracing, we distinguish between new labelled and pre-existing OM and show that new OM is preferentially attached to already present organo-mineral clusters. Vogel, C., Mueller, C.W., Höschen, C., Buegger, F., Heister, K., Schulz, S., Schloter, M., Kögel-Knabner, I., 2014. Submicron structures provide

  5. The efficiency and stability of bubble formation by acoustic vaporization of submicron perfluorocarbon droplets

    NARCIS (Netherlands)

    Reznik, Nikita; Shpak, Oleksandr; Gelderblom, Erik C.; Williams, Ross; Jong, de Nico; Versluis, Michel; Burns, Peter N.

    2013-01-01

    Submicron droplets of liquid perfluorocarbon converted into microbubbles with applied ultrasound have been studied, for a number of years, as potential next generation extravascular ultrasound contrast agents. In this work, we conduct an initial ultra-high-speed optical imaging study to examine the

  6. Submicron hollow spot generation by solid immersion lens and structured illumination

    NARCIS (Netherlands)

    Kim, M.S.; Assafrao, A.C.; Scharf, T.; Wachters, A.J.H.; Pereira, S.F.; Urbach, H.P.; Brun, M.; Olivier, S.; Nicoletti, S.; Herzig, H.P.

    2012-01-01

    We report on the experimental and numerical demonstration of immersed submicron-size hollow focused spots, generated by structuring the polarization state of an incident light beam impinging on a micro-size solid immersion lens (μ-SIL) made of SiO2. Such structured focal spots are characterized by a

  7. Electric and thermal conduction mechanisms of submicron-structured Ni-ZrO2 composites

    Institute of Scientific and Technical Information of China (English)

    范秋林; 胡行方; 郭景坤

    1995-01-01

    The experimental results indicate that the Ni-ZrO2 composites synthesized with urn-sized Ni powder and nm-sized ZrO2 powder possess submicron structure. Based on the fractal theory, the relationship between the electric and thermal conductance and the chemical composition of the composites has been studied. The results show that with the increase of the nickel content, the electric and thermal conductance of the composites varies. It is proposed that in the submicron structured composites, electrons and phonons have different transport mechanisms. The electric transport in the submicron-structured composites can be attributed to the medium punch-through effect and quantum tunnel punch-through effect of electrons and the low thermal conductance is due to the phonic scattering by the submicron-sized pores, grains and grain boundaries. The reason can also be used to explain why the thermal percolation threshold value lags behind the electric percolation value. The phenomenon has been observed.

  8. Submicron organic nanofiber devices with different anode-cathode materials: A simple approach

    DEFF Research Database (Denmark)

    Henrichsen, Henrik Hartmann; Sturm, Heinz; Bøggild, Peter

    2010-01-01

    The authors present a simple general method for simultaneously producing tens of submicron electrode gaps with different cathode and anode materials on top of nanofibers, nanowires, and nanotubes, with an optional gap size variation. Using this method, an ensemble of para-hexaphenylene (p6P...

  9. Submicron hollow spot generation by solid immersion lens and structured illumination

    NARCIS (Netherlands)

    Kim, M.S.; Assafrao, A.C.; Scharf, T.; Wachters, A.J.H.; Pereira, S.F.; Urbach, H.P.; Brun, M.; Olivier, S.; Nicoletti, S.; Herzig, H.P.

    2012-01-01

    We report on the experimental and numerical demonstration of immersed submicron-size hollow focused spots, generated by structuring the polarization state of an incident light beam impinging on a micro-size solid immersion lens (μ-SIL) made of SiO2. Such structured focal spots are characterized by a

  10. Power management of digital circuits in deep sub-micron CMOS technologies

    CERN Document Server

    Henzler, Stephan

    2006-01-01

    In the deep sub-micron regime, the power consumption has become one of the most important issues for competitive design of digital circuits. This book mainly deals with circuit design but also addresses the interface between circuit and system level design on the one side and between circuit and physical design on the other side.

  11. Selective epitaxial growth of sub-micron structures of YBaCuO by substrate modification

    NARCIS (Netherlands)

    Blank, Dave H.A.; Damen, Cas A.J.; Kropman, Boike L.; Rogalla, Horst

    1994-01-01

    Sub-micron structures of high-Tc thin films have been realized with Selective Epitaxial Growth (SEG). Two different techniques to achieve SEG have been studied. First, narrow trenches down to 100 nm are etched into the substrate with a four-layer E-beam lithography technique. Second, amorphous metal

  12. Partitioning and characterization of high speed adder structures in deep-submicron technologies

    Science.gov (United States)

    Estrada, Adrián; Sassaw, Gashaw; Jiménez, Carlos J.; Valencia, Manuel

    2007-05-01

    The availability of higher performance (in area, time and power consumption) and greater precision binary adders is a constant requirement in digital systems. Consequently, the design and characterization of adders and, most of all, their adaptation to the requisites of present-day deep-submicron technologies, are today still issues of concern. The binary adder structures in deep-submicron technologies must be revised to achieve the best balance between the number of bits in the adder and its delay, area and power consumption. It is therefore very important to make an effort to carefully optimize adder structures, thus obtaining improvements in digital systems. This communication presents the optimization of adder structures for implementations in deep-submicron technologies through their partitioning into blocks. This partitioning consists of dividing the number of input bits to the adder into several subsets of bits that will constitute the inputs to several adder structures of the same or of different types. The structures used to accomplish this study range from the more traditional types, such as the carry look ahead adder, the ripple carry adder or the carry select adder, to more innovative kinds, like the parallel prefix adders of the type proposed by Brent-Kung, Han-Carlson, Kogge-Stone or Ladner-Fischer. The analyses carried out allow the characterization of structures implemented in deep-submicron technologies for area, delay and power consumption parameters.

  13. High-Performance Deep SubMicron CMOS Technologies with Polycrystalline-SiGe Gates

    NARCIS (Netherlands)

    Ponomarev, Youri V.; Stolk, Peter A.; Salm, Cora; Schmitz, Jurriaan; Woerlee, P.H.

    2000-01-01

    The use of polycrystalline SiGe as the gate material for deep submicron CMOS has been investigated. A complete compatibility to standard CMOS processing is demonstrated when polycrystalline Si is substituted with SiGe (for Ge fractions below 0.5) to form the gate electrode of the transistors. Perfor

  14. A facile route for the synthesis of sub-micron sized hollow and multiporous organosilica spheres

    NARCIS (Netherlands)

    Segers,M.; Arfsten, N.; Buskens, P.; Möller, M.

    2014-01-01

    We present a facile route for the synthesis of sub-micron sized hollow and multiporous organosilica spheres, which is based on an oil-in-water emulsion and merely uses one organosilica precursor-phenyl trimethoxysilane-that serves as monomer, precursor for a surface active species and oil phase. Thi

  15. Bloch-wave engineered submicron-diameter quantum-dot micropillars for cavity QED experiments

    DEFF Research Database (Denmark)

    Gregersen, Niels; Lermer, Matthias; Reitzenstein, Stephan;

    2013-01-01

    The semiconductor micropillar is attractive for cavity QED experiments. For strong coupling, the figure of merit is proportional to Q/√V, and a design combining a high Q and a low mode volume V is thus desired. However, for the standard submicron diameter design, poor mode matching between...

  16. Reversal studies on sub-micron Co-Cr thin films by AHE analysis

    NARCIS (Netherlands)

    Haan, de S.; Lodder, J.C.

    1996-01-01

    In this study three Co---Cr thin films, prepared under different deposition conditions, are investigated. They have values for the coercivity (Hc) of 11, 90 and 170 kA/m, respectively. The anomalous Hall effect (AHE) has been used to record the hysteresis curves of specially prepared sub-micron Hall

  17. On-chip detection of ferromagnetic resonance of a single submicron Permalloy strip

    NARCIS (Netherlands)

    Costache, M. V.; Sladkov, M.; van der Wal, C. H.; van Wees, B. J.

    2006-01-01

    The authors measured ferromagnetic resonance of a single submicron ferromagnetic strip, embedded in an on-chip microwave transmission line device. The method used is based on detection of the oscillating magnetic flux due to the magnetization dynamics, with an inductive pickup loop. The dependence o

  18. Suppression and origin of soft ESD failures in a submicron CMOS process

    NARCIS (Netherlands)

    Kuper, Fred; Luchies, Jan Marc; Bruines, Joop

    1994-01-01

    Soft failures occurring after low-level ESD stress of thick and thin oxide NMOSTs in a submicron CMOS process have been studied. Simple drain engineering appears to have a dramatic improving effect. Simulation is used to study the cause for the soft failures.

  19. Large voltage modulation in superconducting quantum interference devices with submicron-scale step-edge junctions

    Science.gov (United States)

    Lam, Simon K. H.

    2017-09-01

    A promising direction to improve the sensitivity of a SQUID is to increase its junction's normal resistance value, Rn, as the SQUID modulation voltage scales linearly with Rn. As a first step to develop highly sensitive single layer SQUID, submicron scale YBCO grain boundary step edge junctions and SQUIDs with large Rn were fabricated and studied. The step-edge junctions were reduced to submicron scale to increase their Rn values using focus ion beam, FIB and the measurement of transport properties were performed from 4.3 to 77 K. The FIB induced deposition layer proves to be effective to minimize the Ga ion contamination during the FIB milling process. The critical current-normal resistance value of submicron junction at 4.3 K was found to be 1-3 mV, comparable to the value of the same type of junction in micron scale. The submicron junction Rn value is in the range of 35-100 Ω, resulting a large SQUID modulation voltage in a wide temperature range. This performance promotes further investigation of cryogen-free, high field sensitivity SQUID applications at medium low temperature, e.g. at 40-60 K.

  20. High-Performance Deep SubMicron CMOS Technologies with Polycrystalline-SiGe Gates

    NARCIS (Netherlands)

    Ponomarev, Youri V.; Stolk, Peter A.; Salm, Cora; Schmitz, Jurriaan; Woerlee, P.H.

    2000-01-01

    The use of polycrystalline SiGe as the gate material for deep submicron CMOS has been investigated. A complete compatibility to standard CMOS processing is demonstrated when polycrystalline Si is substituted with SiGe (for Ge fractions below 0.5) to form the gate electrode of the transistors.

  1. Influences of Substrate Adhesion and Particle Size on the Shape Memory Effect of Polystyrene Particles.

    Science.gov (United States)

    Cox, Lewis M; Killgore, Jason P; Li, Zhengwei; Long, Rong; Sanders, Aric W; Xiao, Jianliang; Ding, Yifu

    2016-04-19

    Formulations and applications of micro- and nanoscale polymer particles have proliferated rapidly in recent years, yet knowledge of their mechanical behavior has not grown accordingly. In this study, we examine the ways that compressive strain, substrate surface energy, and particle size influence the shape memory cycle of polystyrene particles. Using nanoimprint lithography, differently sized particles are programmed into highly deformed, temporary shapes in contact with substrates of differing surface energies. Atomic force microscopy is used to obtain in situ measurements of particle shape recovery kinetics, and scanning electron microscopy is employed to assess differences in the profiles of particles at the conclusion of the shape memory cycle. Finally, finite element models are used to investigate the growing impact of surface energies at smaller length scales. Results reveal that the influence of substrate adhesion on particle recovery is size-dependent and can become dominating at submicron length scales.

  2. Nanoparticle-lipid bilayer interactions studied with lipid bilayer arrays

    Science.gov (United States)

    Lu, Bin; Smith, Tyler; Schmidt, Jacob J.

    2015-04-01

    The widespread environmental presence and commercial use of nanoparticles have raised significant health concerns as a result of many in vitro and in vivo assays indicating toxicity of a wide range of nanoparticle species. Many of these assays have identified the ability of nanoparticles to damage cell membranes. These interactions can be studied in detail using artificial lipid bilayers, which can provide insight into the nature of the particle-membrane interaction through variation of membrane and solution properties not possible with cell-based assays. However, the scope of these studies can be limited because of the low throughput characteristic of lipid bilayer platforms. We have recently described an easy to use, parallel lipid bilayer platform which we have used to electrically investigate the activity of 60 nm diameter amine and carboxyl modified polystyrene nanoparticles (NH2-NP and COOH-NP) with over 1000 lipid bilayers while varying lipid composition, bilayer charge, ionic strength, pH, voltage, serum, particle concentration, and particle charge. Our results confirm recent studies finding activity of NH2-NP but not COOH-NP. Detailed analysis shows that NH2-NP formed pores 0.3-2.3 nm in radius, dependent on bilayer and solution composition. These interactions appear to be electrostatic, as they are regulated by NH2-NP surface charge, solution ionic strength, and bilayer charge. The ability to rapidly measure a large number of nanoparticle and membrane parameters indicates strong potential of this bilayer array platform for additional nanoparticle bilayer studies.The widespread environmental presence and commercial use of nanoparticles have raised significant health concerns as a result of many in vitro and in vivo assays indicating toxicity of a wide range of nanoparticle species. Many of these assays have identified the ability of nanoparticles to damage cell membranes. These interactions can be studied in detail using artificial lipid bilayers, which

  3. Dissipative Quantum Tunneling of a Single Defect in a Submicron Bismuth Wire Below 1 K

    Science.gov (United States)

    Chun, Kookjin

    The quantum mechanical problem of a particle tunneling in a double-well potential is of great theoretical and experimental interest. Interaction of the tunneling system with a dissipative environment can have a striking effect on the tunneling dynamics. A very interesting case is that of ohmic dissipation, which occurs when an atom tunnels in a metal in the presence of conduction electrons. We have studied the electrical resistance of submicron Bi wires at low temperature. Due to quantum interference of the conduction electrons, the resistance is highly sensitive to the motion of even a single scattering center. We observe discrete switching of the resistance due to the motion of bistable defects in the sample. We have measured the tunneling rates of a particular defect over the temperature range 0.1-2 K and magnetic field range 0-7 T. The energy asymmetry, varepsilon, of this defect varied over the range 40-420 mK depending on the value of the magnetic field. The temperature dependence of the tunneling rates is qualitatively different for the cases k_{B}T effect of Joule heating on the dynamics of the defect in the same sample. The ratio of the fast and slow transition rates of a defect depends on temperature through the detailed balance relation, gamma_{f}/ gamma_{s} e^ {varepsilon / k_{B}T}. We interpret this ratio as a local thermometer. When varepsilon / k_{B}T > 1, this ratio is sensitive to small changes in the temperature T seen by the defect. Since the defect is strongly coupled to the conduction electrons in the sample below 1 K, we interpret its sensitivity to drive current as an indication of electron heating. As the drive current increases, the defect temperature approaches a power law dependence with the drive current, independent of the nominal lattice temperature. The data are consistent with a simple model of heating, and strong thermal coupling between the defect and the electron bath. We also tried to measure the electron temperature directly

  4. Computational Modelling of Gas-Particle Flows with Different Particle Morphology in the Human Nasal Cavity

    Directory of Open Access Journals (Sweden)

    Kiao Inthavong

    2009-01-01

    Full Text Available This paper summarises current studies related to numerical gas-particle flows in the human nasal cavity. Of interest are the numerical modelling requirements to consider the effects of particle morphology for a variety of particle shapes and sizes such as very small particles sizes (nanoparticles, elongated shapes (asbestos fibres, rough shapes (pollen, and porous light density particles (drug particles are considered. It was shown that important physical phenomena needed to be addressed for different particle characteristics. This included the Brownian diffusion for submicron particles. Computational results for the nasal capture efficiency for nano-particles and various breathing rates in the laminar regime were found to correlate well with the ratio of particle diffusivity to the breathing rate. For micron particles, particle inertia is the most significant property and the need to use sufficient drag laws is important. Drag correlations for fibrous and rough surfaced particles were investigated to enable particle tracking. Based on the simulated results, semi-empirical correlations for particle deposition were fitted in terms of Peclet number and inertial parameter for nanoparticles and micron particles respectively.

  5. Solid lipid nanoparticles and nanostructured lipid carriers--innovative generations of solid lipid carriers.

    Science.gov (United States)

    Shidhaye, S S; Vaidya, Reshma; Sutar, Sagar; Patwardhan, Arati; Kadam, V J

    2008-10-01

    The first generation of solid lipid carrier systems in nanometer range, Solid Lipid Nanoparticles (SLN), was introduced as an alternative to liposomes. SLN are aqueous colloidal dispersions, the matrix of which comprises of solid biodegradable lipids. SLN are manufactured by techniques like high pressure homogenization, solvent diffusion method etc. They exhibit major advantages such as modulated release, improved bioavailability, protection of chemically labile molecules like retinol, peptides from degradation, cost effective excipients, improved drug incorporation and wide application spectrum. However there are certain limitations associated with SLN, like limited drug loading capacity and drug expulsion during storage, which can be minimized by the next generation of solid lipids, Nanostructured lipid carriers (NLC). NLC are lipid particles with a controlled nanostructure that improves drug loading and firmly incorporates the drug during storage. Owing to their properties and advantages, SLN and NLC may find extensive application in topical drug delivery, oral and parenteral administration of cosmetic and pharmaceutical actives. Cosmeceuticals is emerging as the biggest application target of these carriers. Carrier systems like SLN and NLC were developed with a perspective to meet industrial needs like scale up, qualification and validation, simple technology, low cost etc. This paper reviews present status of SLN and NLC as carrier systems with special emphasis on their application in Cosmeceuticals; it also gives an overview about various manufacturing techniques of SLN and NLC.

  6. Time-specific measurements of energy deposition from radiation fields in simulated sub-micron tissue volumes

    Energy Technology Data Exchange (ETDEWEB)

    Famiano, M.A.

    1997-07-07

    A tissue-equivalent spherical proportional counter is used with a modified amplifier system to measure specific energy deposited from a uniform radiation field for short periods of time ({approximately}1 {micro}s to seconds) in order to extrapolate to dose in sub-micron tissue volumes. The energy deposited during these time intervals is compared to biological repair processes occurring within the same intervals after the initial energy deposition. The signal is integrated over a variable collection time which is adjusted with a square-wave pulse. Charge from particle passages is collected on the anode during the period in which the integrator is triggered, and the signal decays quickly to zero after the integrator feedback switch resets; the process repeats for every triggering pulse. Measurements of energy deposited from x rays, {sup 137}Cs gamma rays, and electrons from a {sup 90}Sr/{sup 90}Y source for various time intervals are taken. Spectral characteristics as a function of charge collection time are observed and frequency plots of specific energy and collection time-interval are presented. In addition, a threshold energy flux is selected for each radiation type at which the formation of radicals (based on current measurements) in mammalian cells equals the rate at which radicals are repaired.

  7. Sol-Gel Synthesis, Characterization and Optical Properties of Bi 3+ - Doped CdO Sub-Micron Size Materials

    Directory of Open Access Journals (Sweden)

    Sh. Khademinia

    2013-03-01

    Full Text Available Highly crystalline Bi3+-doped cadmium oxide (CdO sub-micron structures were synthesized by calcination the obtained precursor from a sol-gel reaction. The reaction was carried out with cadmium nitrate (Cd(NO32.4H2O, bismuth nitrate (Bi(NO33.5H2O and ethylene glycol (C2H6O2 reactants without any additives at 80°C for 2h. Resulting gel was calcined at 900 °C with increasing temperature rate of 15°C per minute for 12 h in a furnace. As a result of heating, the organic section of gel was removed and Bi3+-doped cadmium oxide micro structure was produced. The obtained compound from the sol-gel technique possesses a cubic crystalline structure at micro scale. Powder x-ray diffraction (PXRD study indicated that the obtained Bi3+-doped CdO has a cubic phase. Also, SEM images showed that the resulting material is composed of particles with the average diameter of 1 µm. Also, UV–vis and FT-IR spectroscopies were employed to characterize the Bi3+-doped CdO micro structures.

  8. Computational studies of plasma lipoprotein lipids.

    Science.gov (United States)

    Pan, Lurong; Segrest, Jere P

    2016-10-01

    Plasma lipoproteins are macromolecular assemblies of proteins and lipids found in the blood. The lipid components of lipoproteins are amphipathic lipids such as phospholipids (PLs), and unesterified cholesterols (UCs) and hydrophobic lipids such as cholesteryl esters (CEs) and triglycerides (TGs). Since lipoproteins are soft matter supramolecular assemblies easily deformable by thermal fluctuations and they also exist in varying densities and protein/lipid components, a detailed understanding of their structure/function is experimentally difficult. Molecular dynamics (MD) simulation has emerged as a particularly promising way to explore the structure and dynamics of lipoproteins. The purpose of this review is to survey the current status of computational studies of the lipid components of the lipoproteins. Computational studies aim to explore three levels of complexity for the 3-dimensional structural dynamics of lipoproteins at various metabolic stages: (i) lipoprotein particles consist of protein with minimal lipid; (ii) lipoprotein particles consist of PL-rich discoidal bilayer-like lipid particles; (iii) mature circulating lipoprotein particles consist of CE-rich or TG-rich spheroidal lipid-droplet-like particles. Due to energy barriers involved in conversion between these species, other biomolecules also participate in lipoprotein biological assembly. For example: (i) lipid-poor apolipoprotein A-I (apoA-I) interacts with ATP-binding cassette transporter A1 (ABCA1) to produce nascent discoidal high density lipoprotein (dHDL) particles; (ii) lecithin-cholesterol acyltransferase (LCAT) mediates the conversion of UC to CE in dHDL, driving spheroidal HDL (sHDL) formation; (iii) transfer proteins, cholesterol ester transfer protein (CETP) and phospholipid transfer protein (PLTP), transfer both CE and TG and PL, respectively, between lipoprotein particles. Computational studies have the potential to explore different lipoprotein particles at each metabolic stage in

  9. Effect of different lipids and surfactants on formulation of solid lipid nanoparticles incorporating tamoxifen citrate

    Directory of Open Access Journals (Sweden)

    S U Upadhyay

    2012-01-01

    Full Text Available Tamoxifen Citrate (TC is an estrogen receptor antagonist and drug of choice for hormone sensitive breast cancer. Solid Lipid Nanoparticles loaded with TC were prepared by High Shear Homogenization followed by Ultrasonication. The aim of the present work is to study the effect of four different Solid Lipids and three Surfactants on Formulation and Stability of SLN. They were characterized for Particle size, Polydispersity Index and Zeta Potential by Zetasizer Nano. SLN prepared by Solid Lipid Compritol 888 (Glyceryldibehenate and Tween 80 (1% showed desired Particle Size of 206.9 nm, PDI of 0.046 and Zeta Potential of 9.32 mV.

  10. Comparison of the Kinetic Behaviors of Fe{sub 2}O{sub 3} Spherical Submicron Clusters and Fe{sub 2}O{sub 3} Fine Powder Catalysts for CO Oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Seunggyun; Kim, Jinhoon; Lee, Sunghan [Yonsei Univ., Wonju (Korea, Republic of); Kim, Unho; Jung, Jinseung [Gangneung-Wonju National Univ., Gangneung (Korea, Republic of)

    2014-05-15

    α-Fe{sub 2}O{sub 3} spherical particles having an average diameter of ca. 420 nm and α-Fe{sub 2}O{sub 3} fine particles (< 10 μm particle size) were prepared to examine as catalysts for CO oxidation. Kinetic studies on the catalytic reactions were performed in a flow reactor using an on-line gas chromatography system operated at 1 atm. The apparent activation energies and the partial orders with respect to CO and O{sub 2} were determined from the rates of CO disappearance in the reaction stage showing a constant catalytic activity. In the temperature range of 150-275 .deg. C, the apparent activation energies were calculated to be 13.7 kcal/mol on the α-Fe{sub 2}O{sub 3} spherical submicron clusters and 15.0 kcal/mol on the α-Fe{sub 2}O{sub 3} fine powder. The Pco and PO{sub 2} dependencies of rate were investigated at various partial pressures of CO and O{sub 2} at 250 .deg. C. Zero-order kinetics were observed for O{sub 2} on both the catalysts, but the reaction order for CO was observed as first-order on the α-Fe{sub 2}O{sub 3} fine powder and 0.75-order on the α-Fe{sub 2}O{sub 3} spherical submicron clusters. The catalytic processes including the inhibition process by CO{sub 2} on the α-Fe{sub 2}O{sub 3} spherical submicron powder are discussed according to the kinetic results. The catalysts were characterized using XRD (X-ray powder diffraction), FE-SEM (field emission-scanning electron microscopy), HR-TEM (high resolution-transmission electron microscopy), and N{sub 2} sorption measurements.

  11. Lipid signaling in plants

    NARCIS (Netherlands)

    Munnik, T.

    2010-01-01

    This book highlights the current status of plant lipid signaling. Written by leading researchers in the field, the chapters include detailed information on the measurement, regulation and function of phospholipases, lipid kinases, lipid phosphatases, inositolpolyphosphates, polyphosphoinositides, ph

  12. Lipid Metabolism Disorders

    Science.gov (United States)

    ... metabolic disorder, something goes wrong with this process. Lipid metabolism disorders, such as Gaucher disease and Tay-Sachs disease, involve lipids. Lipids are fats or fat-like substances. They ...

  13. Plant lipid signaling protocols

    NARCIS (Netherlands)

    Munnik, T.; Heilmann, I.

    2013-01-01

    Eukaryotic cells are surrounded by membranes consisting of various lipids, including sterols, sphingolipids, glycolipids, and phospholipids. Besides structural functions, membranes also contain lipids with regulatory and signaling roles. Such lipids include polyphosphoinositides, the low-abundant

  14. Submicron area NbN/MgO/NbN tunnel junctions for SIS mixer applications

    Science.gov (United States)

    Leduc, H. G.; Judas, A.; Cypher, S. R.; Bumble, B.; Hunt, B. D.

    1991-01-01

    The development of submicron area mixer elements for operation in the submillimeter wave range is discussed. High-current-density NbN/MgO/NbN tunnel junctions with areas down to 0.1 sq microns have been fabricated in both planar and edge geometries. The planar junctions were fabricated from in situ deposited trilayers using electron-beam lithography to pattern submicron area mesas. Modifications of fabrication techniques used in larger-area NbN tunnel junctions are required and are discussed. The NbN/MgO/NbN edge junction process using sapphire substrates has been transferred to technologically important quartz substrates using MgO buffer layers to minimize substrate interactions. The two junction geometries are compared and contrasted in the context of submillimeter wave mixer applications.

  15. Novel submicronized rebamipide liquid with moderate viscosity: significant effects on oral mucositis in animal models.

    Science.gov (United States)

    Nakashima, Takako; Sako, Nobutomo; Matsuda, Takakuni; Uematsu, Naoya; Sakurai, Kazushi; Ishida, Tatsuhiro

    2014-01-01

    This study aimed at developing a novel rebamipide liquid for an effective treatment of oral mucositis. The healing effects of a variety of liquids comprising submicronized rebamipide crystals were investigated using a rat cauterization-induced oral ulcer model. Whereas 2% rebamipide liquid comprising micro-crystals did not exhibit significant curative effect, 2% rebamipide liquids comprising submicronized crystals with moderate viscosities exhibited healing effects following intra-oral administration. The 2% and 4% optimized rebamipide liquids showed significant healing effects in the rat oral ulcer model (prebamipide liquid significantly reduced the percent area of ulcerated injury (prebamipide liquid with moderate viscosity following intra-oral administration showed better both healing effect in the rat oral ulcer model and preventive effect in the rat irradiation-induced glossitis model.

  16. Generating Sub-Micron Features On Rough Surfaces Using Optical Trap Assisted Nanopatterning

    Science.gov (United States)

    Tsai, Yu-Cheng; Fardel, Romain; Arnold, Craig B.

    2010-10-01

    Near-field intensity enhancement enables laser modification of materials with feature sizes below the classical diffraction limit. However, the need to maintain close distances between the objective element and the substrate typically limit demonstrations of this technology to flat surfaces, even though there are many cases where the ability to produce sub-micron features on rough or structured surfaces are needed. Here, we show the use of a new technique, optical trap assisted nanopatterning (OTAN), for the production of nanoscale features on rippled substrates. The ability to position a microbead near-field objective close to the surface without the need for active feedback and control allows one to continuously move the bead across a rough surface without sticking. Sub-micron patterning of polyimide is demonstrated on surfaces with 1.1 μm steps showing good uniformity. Finally, the enabling technology allows for straightforward parallelization where multiple patterns can be created simultaneously over surface.

  17. Fabrication of submicron chalcogenide glass photonic crystal by resist-free nanoimprint lithography

    Science.gov (United States)

    Zeng, Jianghui; Zhang, Qian; Zhang, Peiqing; Tang, Junzhou; Xu, Yinsheng; Chen, Feifei; Shen, Xiang; Dai, Shixun

    2017-09-01

    We reported the fabrication of submicron photonic crystal with As40Se40Te20 chalcogenide glass by resist-free thermal nanoimprint using a soft stamp. The As40Se40Te20 glass was prepared with melt-quenching method, and measured to have broad transmission range, high linear and nonlinear refractive index, and good thermal stability. Due to the very low glass transition temperature, the thermal nanoimprint was accomplished directly on the resist-free bulk glass with the soft stamp. By choosing suitable imprint condition, submicron chalcogenide glass photonic crystal with the band gap covering telecom wavelength was obtained. Taking advantage of the high nonlinearity of As40Se40Te20 glass, the imprinted PC structure may have potential applications for all-optical switch in optical communications.

  18. Preparation techniques of the submicron lithium titanate materials by electro-spinning

    Science.gov (United States)

    Wang, Yudong; Yang, Kai; Gao, Fei; Liu, Hao; Zhang, Mingjie

    2017-01-01

    Combining sol-gel process and electro-spinning, the submicron lithium titanate materials are prepared with lithium acetate and titanium tetraisopropanolate respectively as the lithium and titanium sources, and polyvinylpyrrolidone (PVP) as the template. It's found by scanning electron microscope(SEM )that, the prepared lithium titanate materials are characterized by the fiber diameter 150~200nm, a large number of irregular indentations in the surface, and the larger specific surface area than that before calcination. The lithium titanate cell receives charge-discharge test and cyclic voltammetry. The capacity of the submicron lithium titanate materials is up to 160mAh·g-1 at the rate of 0.1C, and it's revealed by cyclic voltammetry that the cell in the charge or discharge process undergoes a single redox reaction, but having good reversibility.

  19. Impact of Device Architecture on Performance and Reliability of Deep Submicron SOI MOSFETs (invited paper)

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The main electrical properties of advanced Silicon-On-Insulator MOSFETs are addressed. The subthreshold and high field operations are analysed as a function of device architecture. The special SOI parasitic phenomena, such as the floating body potential and temperature, are critically reviewed. The main limitations of submicron MOSFET are comparatively evaluated for various SOI structures. Short channel and hot carrier effects as well as the reliability of the SOI technology are investigated for gate length down to sub-0. 1 micron.

  20. DARPA-URI Consortium Meetings on Submicron Heterostructures of Diluted Magnetic Semiconductors.

    Science.gov (United States)

    1987-01-01

    B 35, 7464 (1987). 46. S. Rodriguez, A. Camacho and L. Quiroga, "Electrostatic and Magnetostatic Modes in Semiconductor Superlattices", (to appear in...AD-RI93 499 DARPA-URI CONSORTIUM MEETINGS ON SUSMICRON IETEROSTRUCTURES OF DILUTED MAGNETIC SEMICONDUCTORS (U) PURDUE UNIV LRFRYETTE IN 1987 N91114-86...o FILE COPY (SUBMICRON HETEROSTRUCTURES ,it OF DILUTED MAGNETIC SEMICONDUCTORS ANNUAL REPORT 1986-87 The Principal Investigators along with their co

  1. 1.55 Micrometer Sub-Micron Finger, Interdigitated MSM Photodetector Arrays with Low Dark Current

    Science.gov (United States)

    2010-02-02

    morphology is generally smoother. These transparent conducting oxides may also be used as electrodes in solar cells and flat-panel display devices...REPORT Final Report of 1.55 UM Sub-Micron Finger, Interdigitated MSM Photodetector Arrays with Low Dark Current 14. ABSTRACT 16. SECURITY... Interdigitated MSM Photodetector Arrays with Low Dark Current Sponsored by: U. S. Army Research Office Dr. Michael D. Gerhold Contract

  2. Radiation pressure on fluffy submicron-sized grains

    CERN Document Server

    Silsbee, Kedron

    2015-01-01

    We investigate the claim that the ratio {\\beta} of radiation pressure force to gravitational force on a dust grain in our solar system can substantially exceed unity for some grain sizes, provided that grain porosity is high enough. For model grains consisting of random aggregates of silicate spherules, we find that the maximum value of {\\beta} is almost independent of grain porosity, but for small (<0.3 {\\mu}m) grains, {\\beta} actually decreases with increasing porosity. These results affect the interpretation of the grain trajectories estimated from the Stardust mission, which were modeled assuming {\\beta} values exceeding one. We find that radiation pressure effects are not large enough for particles Orion and Hylabrook captured by Stardust to be of interstellar origin given their reported impact velocities. We also investigate the effect of metallic iron inclusions in the dust grains, and find that metallic iron will increase {\\beta}, but at least half the grain (by mass) must be iron in order to raise...

  3. Reducing DRIFT Backgrounds with a Submicron Aluminized-Mylar Cathode

    CERN Document Server

    Battat, James B R; Dorofeev, Alexei; Ezeribe, Anthony C; Fox, Jennifer R; Gauvreau, Jean-Luc; Gold, Michael; Harmon, Lydia; Harton, John; Lafler, Randy; Lauer, Robert J; Lee, Eric R; Loomba, Dinesh; Lumnah, Alexander; Matthews, John; Miller, Eric H; Mouton, Frederic; Murphy, Alexander St J; Phan, Nguyen; Sadler, Stephen W; Scarff, Andrew; Schuckman, Fred; Snowden-Ifft, Daniel; Spooner, Neil J C; Walker, Daniel

    2015-01-01

    Background events in the DRIFT-IId dark matter detector, mimicking potential WIMP signals, are predominantly caused by alpha decays on the central cathode in which the alpha particle is completely or partially absorbed by the cathode material. We installed a 0.9 micron thick aluminized-mylar cathode as a way to reduce the probability of producing these backgrounds. We study three generations of cathode (wire, thin-film, and radiologically clean thin-film) with a focus on the ratio of background events to alpha decays. Two independent methods of measuring the absolute alpha decay rate are used to ensure an accurate result, and agree to within $10\\%$. Using alpha range spectroscopy, we measure the radiologically cleanest cathode version to have a contamination of $3.3\\pm0.1$ ppt $^{234}$U and $73\\pm2$ ppb $^{238}$U. This cathode reduces the probability of producing an RPR from an alpha decay by a factor of $70\\pm20$ % while reducing the overall background rate by $96.5\\pm0.5\\%$ compared to the original stainles...

  4. Directed assembly of conducting polymers on sub-micron templates by electrical fields

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Jia; Wei, Ming [National Science Foundation (NSF) Nanoscale Science and Engineering Center for High-Rate Nanomanufacturing, University of Massachusetts Lowell, Lowell, MA 01854 (United States); Busnaina, Ahmed [National Science Foundation (NSF) Nanoscale Science and Engineering Center for High-Rate Nanomanufacturing, Northeastern University, Boston, MA 02115 (United States); Barry, Carol [National Science Foundation (NSF) Nanoscale Science and Engineering Center for High-Rate Nanomanufacturing, University of Massachusetts Lowell, Lowell, MA 01854 (United States); Mead, Joey, E-mail: Joey_Mead@uml.edu [National Science Foundation (NSF) Nanoscale Science and Engineering Center for High-Rate Nanomanufacturing, University of Massachusetts Lowell, Lowell, MA 01854 (United States)

    2013-02-20

    Highlights: Black-Right-Pointing-Pointer Nanoscale patterns with dimensions of assembled PANi down to 100 nm were fabricated. Black-Right-Pointing-Pointer We use electrophoretic and dielectrophoretic assembly to deposit PANi. Black-Right-Pointing-Pointer Electrophoretic and dielectrophoretic assembly of PANi finished in less than 1 min. Black-Right-Pointing-Pointer Effect of process parameters on assembly of PANi onto nanoscale pattern was studied. Black-Right-Pointing-Pointer The assembled PANi can be transferred to other flexible substrates. - Abstract: Patterning of conducting polymer into sub-micron patterns over large areas at high rate and low cost is significant for commercial manufacturing of novel devices. Electrophoretic and dielectrophoretic assembly provide an easily scaled approach with high fabrication rates. In this work, electrophoretic and dielectrophoretic assembly were used to assemble polyaniline (PANi) into multiscale sub-micron size patterns in less than 1 min. The process was controlled by assembly time, amplitude, and frequency of the electric field. Dielectrophoretic assembly is preferable for manufacturing as it reduces damage to the templates used to control the assembly. Using this method, sub-micron patterns with dimensions of the assembled PANi down to 100 nm were fabricated over large areas in short times. The assembled PANi was further transferred to other flexible polymer substrates by a thermoforming process, providing a fast, easily controlled and promising approach for fabrication of nanoscale devices.

  5. Continuous Draw Spinning of Extra-Long Silver Submicron Fibers with Micrometer Patterning Capability.

    Science.gov (United States)

    Bai, Xiaopeng; Liao, Suiyang; Huang, Ya; Song, Jianan; Liu, Zhenglian; Fang, Minghao; Xu, Chencheng; Cui, Yi; Wu, Hui

    2017-03-08

    Ultrathin metal fibers can serve as highly conducting and flexible current and heat transport channels, which are essential for numerous applications ranging from flexible electronics to energy conversion. Although industrial production of metal fibers with diameters of down to 2 μm is feasible, continuous production of high-quality and low-cost nanoscale metal wires is still challenging. Herein, we report the continuous draw spinning of highly conductive silver submicron fibers with the minimum diameter of ∼200 nm and length of more than kilometers. We obtained individual AgNO3/polymer fibers by continuous drawing from an aqueous solution at a speed of up to 8 m/s. With subsequent heat treatment, freestanding Ag submicron fibers with high mechanical flexibility and electric conductivity have been obtained. Woven mats of aligned Ag submicron fibers were used as transparent electrodes with high flexibility and high performance with sheet resistance of 7 Ω sq(-1) at a transparency of 96%. Continuous draw spinning opened new avenues for scalable, flexible, and ultralow-cost fabrication of extra-long conductive ultrathin metal fibers.

  6. A new route for the synthesis of submicron-sized LaB{sub 6}

    Energy Technology Data Exchange (ETDEWEB)

    Lihong, Bao; Wurentuya,; Wei, Wei; Tegus, O., E-mail: tegusph@imnu.edu.cn

    2014-11-15

    Submicron crystalline LaB{sub 6} has been successfully synthesized by a solid-state reaction of La{sub 2}O{sub 3} with NaBH{sub 4} at 1200 °C. The effects of reaction temperature on the crystal structure, grain size and morphology were investigated by X-ray diffraction, scanning electron microscope and transmission electron microscope. It is found that when the reaction temperature is in the range of 1000–1100 °C, there are ultrafine nanoparticles and nanocrystals that coexist. When the reaction temperature elevated to 1200 °C, the grain morphology transformed from ultrafine nanoparticle to submicron crystals completely. High resolution transmission electron microscope images fully confirm the formation of LaB{sub 6} cubic structure. - Highlights: • Single-phased LaB{sub 6} have been synthesized by a solid-state reaction in a continuous evacuating process. • The reaction temperature has a important effect on the phase composition. • The grain size increase from nano-size to submicron with increasing reaction temperature.

  7. Ordered YBCO sub-micron array structures induced by pulsed femtosecond laser irradiation.

    Science.gov (United States)

    Luo, C W; Lee, C C; Li, C H; Shih, H C; Chen, Y-J; Hsieh, C C; Su, C H; Tzeng, W Y; Wu, K H; Juang, J Y; Uen, T M; Chen, S P; Lin, J-Y; Kobayashi, T

    2008-12-08

    We report on the formation of organized sub-micron YBa(2)Cu(3)O(7) (YBCO) dots induced by irradiating femtosecond laser pulses on YBCO films prepared by pulse laser deposition with fluence in the range of 0.21 approximately 0.53 J/cm(2). The morphology of the YBCO film surface depends strongly on the laser fluences irradiated. At lower laser fluence (approximately 0.21 J/cm(2)) the morphology was pattern of periodic ripples with sub-micrometer spacing. Slightly increasing the laser fluence to 0.26 J/cm(2) changes the pattern into organized sub-micron dots with diameters ranging from 100 nm to 800 nm and height of 150 nm. Further increase of the laser fluence to over 0.32 J/cm(2), however, appeared to result in massive melting and led to irregular morphology. The mechanism and the implications of the current findings will be discussed. Arrays of YBCO sub-micron dots with T(c) = 89.7 K were obtained.

  8. Investigating the annual behaviour of submicron secondary inorganic and organic aerosols in London

    Directory of Open Access Journals (Sweden)

    D. E. Young

    2014-07-01

    Full Text Available For the first time, the behaviour of non-refractory inorganic and organic submicron particulate through an entire annual cycle is investigated using measurements from an Aerodyne compact time-of-flight aerosol mass spectrometer (cToF-AMS located at a UK urban background site in North Kensington, London. We show secondary aerosols account for a significant fraction of the submicron aerosol burden and that high concentration events are governed by different factors depending on season. Furthermore, we demonstrate that on an annual basis there is no variability in the extent of secondary organic aerosol (SOA oxidation, as defined by the oxygen content, irrespective of amount. This result is surprising given the changes in precursor emissions and contributions as well as photochemical activity throughout the year; however it may make the characterisation of SOA in urban environments more straightforward than previously supposed. Organic species, nitrate, sulphate, ammonium, and chloride were measured during 2012 with average concentrations (±one standard deviation of 4.32 (±4.42, 2.74 (±5.00, 1.39 (±1.34, 1.30 (±1.52 and 0.15 (±0.24 μg m–3, contributing 43, 28, 14, 13 and 2% to the total submicron mass, respectively. Components of the organic aerosol fraction are determined using positive matrix factorisation (PMF where five factors are identified and attributed as hydrocarbon-like OA (HOA, cooking OA (COA, solid fuel OA (SFOA, type 1 oxygenated OA (OOA1, and type 2 oxygenated OA (OOA2. OOA1 and OOA2 represent more and less oxygenated OA with average concentrations of 1.27 (±1.49 and 0.14 (±0.29 μg m–3, respectively, where OOA1 dominates the SOA fraction (90%. Diurnal, monthly, and seasonal trends are observed in all organic and inorganic species, due to meteorological conditions, specific nature of the aerosols, and availability of precursors. Regional and transboundary pollution as well as other individual pollution events influence

  9. Evaluating model parameterizations of submicron aerosol scattering and absorption with in situ data from ARCTAS 2008

    Science.gov (United States)

    Alvarado, Matthew J.; Lonsdale, Chantelle R.; Macintyre, Helen L.; Bian, Huisheng; Chin, Mian; Ridley, David A.; Heald, Colette L.; Thornhill, Kenneth L.; Anderson, Bruce E.; Cubison, Michael J.; Jimenez, Jose L.; Kondo, Yutaka; Sahu, Lokesh K.; Dibb, Jack E.; Wang, Chien

    2016-07-01

    Accurate modeling of the scattering and absorption of ultraviolet and visible radiation by aerosols is essential for accurate simulations of atmospheric chemistry and climate. Closure studies using in situ measurements of aerosol scattering and absorption can be used to evaluate and improve models of aerosol optical properties without interference from model errors in aerosol emissions, transport, chemistry, or deposition rates. Here we evaluate the ability of four externally mixed, fixed size distribution parameterizations used in global models to simulate submicron aerosol scattering and absorption at three wavelengths using in situ data gathered during the 2008 Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) campaign. The four models are the NASA Global Modeling Initiative (GMI) Combo model, GEOS-Chem v9-02, the baseline configuration of a version of GEOS-Chem with online radiative transfer calculations (called GC-RT), and the Optical Properties of Aerosol and Clouds (OPAC v3.1) package. We also use the ARCTAS data to perform the first evaluation of the ability of the Aerosol Simulation Program (ASP v2.1) to simulate submicron aerosol scattering and absorption when in situ data on the aerosol size distribution are used, and examine the impact of different mixing rules for black carbon (BC) on the results. We find that the GMI model tends to overestimate submicron scattering and absorption at shorter wavelengths by 10-23 %, and that GMI has smaller absolute mean biases for submicron absorption than OPAC v3.1, GEOS-Chem v9-02, or GC-RT. However, the changes to the density and refractive index of BC in GC-RT improve the simulation of submicron aerosol absorption at all wavelengths relative to GEOS-Chem v9-02. Adding a variable size distribution, as in ASP v2.1, improves model performance for scattering but not for absorption, likely due to the assumption in ASP v2.1 that BC is present at a constant mass fraction

  10. Dynamical Modes of Deformed Red Blood Cells and Lipid Vesicles in Flows

    Science.gov (United States)

    Noguchi, H.

    Red blood cells and lipid vesicles exhibit rich behaivor in flows.Their dynamics were studied using a particle-based hydrodynamic simulation method, multi-particle collision dynamics. Rupture of lipid vesicles in simple shear flow was simulated by meshless membrane model. Several shape transitions of lipid vesicles and red blood cells are induced by flows. Transition of a lipid vesicle from budded to prolate shapes with increasing shear rate and ordered alignments of deformed elastic vesicles in high density are presented.

  11. Particle Pollution

    Science.gov (United States)

    ... Your Health Particle Pollution Public Health Issues Particle Pollution Recommend on Facebook Tweet Share Compartir Particle pollution ... see them in the air. Where does particle pollution come from? Particle pollution can come from two ...

  12. FY 2000 Industrial science and technology research and development themes - cooperative project with academic circles. Report on the results of research and development of technologies for creating new bioaffinity molecules using submicron beads (Development of technologies for rational use of energy); 2000 nendo biryushi riyogata seitai ketsugo busshitsu nado sosei gijutsu no kenkyu kaihatsu seika hokokusho. Energy shiyo gorika gijutsu kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-03-01

    Described herein are the FY 2000 results of the research and development for creating new bioaffinity molecules using submicron beads. The program for development of technology for analyzing chemical-biomolecule complexes using submicron affinity beads has developed a detachable linker which allows the complex, composed of ligand on the affinity latex particle surfaces and receptor bound thereto, to be detached directly from the particles, and also developed the prototype of magnetite-containing polymer particles with a diameter of submicron order, which facilitate recovery of the affinity latex. The program for development of technology to create chemical substances with new functions has successfully constructed the focused library composed of 400 compounds based on the split and pool method for FR225659 as a glucose modulator, chosen as the target material. It also has established the method of synthesizing opioid alkaloid as the target compound on the solid phase, and synthesized 39 opioid compounds with condensed indol rings, having diverse of several substituents. (NEDO)

  13. Microparticle Assembly Pathways on Lipid Membranes

    Science.gov (United States)

    van der Wel, Casper; Heinrich, Doris; Kraft, Daniela J.

    2017-09-01

    Understanding interactions between microparticles and lipid membranes is of increasing importance, especially for unraveling the influence of microplastics on our health and environment. Here, we study how a short-ranged adhesive force between microparticles and model lipid membranes causes membrane-mediated particle assembly. Using confocal microscopy, we observe the initial particle attachment to the membrane, then particle wrapping, and in rare cases spontaneous membrane tubulation. In the attached state, we measure that the particle mobility decreases by 26%. If multiple particles adhere to the same vesicle, their initial single-particle state determines their interactions and subsequent assembly pathways: 1) attached particles only aggregate when small adhesive vesicles are present in solution, 2) wrapped particles reversibly attract one another by membrane deformation, and 3) a combination of wrapped and attached particles form membrane-mediated dimers, which further assemble into a variety of complex structures. The experimental observation of distinct assembly pathways induced only by a short ranged membrane-particle adhesion, shows that a cellular cytoskeleton or other active components are not required for microparticle aggregation. We suggest that this membrane-mediated microparticle aggregation is a reason behind reported long retention times of polymer microparticles in organisms.

  14. Influence of locational states of submicron fibers added into matrix on mechanical properties of plain-woven Carbon Fiber Composite

    Science.gov (United States)

    Kumamoto, Soichiro; Okubo, Kazuya; Fujii, Toru

    2016-01-01

    The aim of this study was to show the influence of locational states of submicron fibers added into epoxy matrix on mechanical properties of modified plane-woven carbon fiber reinforced plastic (CFRP). To change the locational states of submicron fibers, two kinds of fabrication processes were applied in preparing specimen by hand lay-up method. Submicron fibers were simply added into epoxy resin with ethanol after they were stirred by a dispersion process using homogenizer to be located far from the interface between reinforcement and matrix. In contrast, submicron fibers were attached onto the carbon fibers by injecting from a spray nozzle accompanying with ethanol to be located near the interface, after they were tentatively contained in ethanol. The plain-woven CFRP plates were fabricated by hand lay-up method and cured at 80 degree-C for 1 hour and then at 150 degree-C for 3 hours. After curing, the plain-woven CFRP plates were cut into the dimension of specimen. Tensile shear strength and Mode-II fracture toughness of CFRP were determined by tensile lap-shear test and End-notched flexure(ENF) test, respectively. When submicron fibers were located far from the interface between carbon fibers and epoxy resin, tensile shear strength and Mode-II fracture toughness of CFRP were improved 30% and 18% compared with those of unmodified case. The improvement ratio in modified case was rather low (about few percentages) in the case where submicron fibers were located near the interface. The result suggested that crack propagation should be prevented when submicron fibers were existed far from the interface due to the effective stress state around the crack tip.

  15. Influence of locational states of submicron fibers added into matrix on mechanical properties of plain-woven Carbon Fiber Composite

    Directory of Open Access Journals (Sweden)

    Kumamoto Soichiro

    2016-01-01

    Full Text Available The aim of this study was to show the influence of locational states of submicron fibers added into epoxy matrix on mechanical properties of modified plane-woven carbon fiber reinforced plastic (CFRP. To change the locational states of submicron fibers, two kinds of fabrication processes were applied in preparing specimen by hand lay-up method. Submicron fibers were simply added into epoxy resin with ethanol after they were stirred by a dispersion process using homogenizer to be located far from the interface between reinforcement and matrix. In contrast, submicron fibers were attached onto the carbon fibers by injecting from a spray nozzle accompanying with ethanol to be located near the interface, after they were tentatively contained in ethanol. The plain-woven CFRP plates were fabricated by hand lay-up method and cured at 80 degree-C for 1 hour and then at 150 degree-C for 3 hours. After curing, the plain-woven CFRP plates were cut into the dimension of specimen. Tensile shear strength and Mode-II fracture toughness of CFRP were determined by tensile lap-shear test and End-notched flexure(ENF test, respectively. When submicron fibers were located far from the interface between carbon fibers and epoxy resin, tensile shear strength and Mode-II fracture toughness of CFRP were improved 30% and 18% compared with those of unmodified case. The improvement ratio in modified case was rather low (about few percentages in the case where submicron fibers were located near the interface. The result suggested that crack propagation should be prevented when submicron fibers were existed far from the interface due to the effective stress state around the crack tip.

  16. Interactions and Translational Dynamics of Phosphatidylinositol Bisphosphate (PIP2) Lipids in Asymmetric Lipid Bilayers.

    Science.gov (United States)

    Shi, Xiaojun; Kohram, Maryam; Zhuang, Xiaodong; Smith, Adam W

    2016-02-23

    Phosphatidylinositol phosphate (PIP) lipids are critical to many cell signaling pathways, in part by acting as molecular beacons that recruit peripheral membrane proteins to specific locations within the plasma membrane. Understanding the biophysics of PIP-protein interactions is critical to developing a chemically detailed model of cell communication. Resolving such interactions is challenging, even in model membrane systems, because of the difficulty in preparing PIP-containing membranes with high fluidity and integrity. Here we report on a simple, vesicle-based protocol for preparing asymmetric supported lipid bilayers in which fluorescent PIP lipid analogues are found only on the top leaflet of the supported membrane facing the bulk solution. With this asymmetric distribution of lipids between the leaflets, the fluorescent signal from the PIP lipid analogue reports directly on interactions between the peripheral molecules and the top leaflet of the membrane. Asymmetric PIP-containing bilayers are an ideal platform to investigate the interaction of PIP with peripheral membrane proteins using fluorescence-based imaging approaches. We demonstrate their usefulness here with a combined fluorescence correlation spectroscopy and single particle tracking study of the interaction between PIP2 lipids and a polycationic polymer, quaternized polyvinylpyridine (QPVP). With this approach we are able to quantify the microscopic features of the mobility coupling between PIP2 lipids and polybasic QPVP. With single particle tracking we observe individual PIP2 lipids switch from Brownian to intermittent motion as they become transiently trapped by QPVP.

  17. High gradient magnetic filtration of cupric oxide and fly ash particles

    Energy Technology Data Exchange (ETDEWEB)

    Lua, A.C. [Nanyang Technological University (Singapore). School of Mechanical and Production Engineering

    1996-12-31

    High gradient magnetic filtration (HGMF) tests have been carried out on cupric oxide particles and power plant fly ash which were dispersed in air streams. An experimental test rig was set up to conduct these tests. Results showed that for cupric oxide particles, filtration efficiencies of up to 95% were obtained for submicron sizes with dust loadings of up to 0.36 time the matrix volume. For fly ash, filtration efficiencies of up to 65% were obtained for submicron particles. However, all particle sizes showed progressive deterioration in efficiencies with loading. At the end of the test, the matrix had collected 0.52 times its own mass of fly ash. 2 refs., 7 figs.

  18. FY 2000 Industrial science and technology research and development themes - cooperative project with academic circles. Report on the results of research and development for creating new bioaffinity molecules using submicron beads (Research and development for creating new bioaffinity molecules using submicron beads); 2000 nendo biryushi riyogata seitai ketsugo busshitsu nado sosei gijutsu no kenkyu kaihatsu seika hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-03-01

    Described herein are the FY 2000 results of the research and development of technologies for creating new bioaffinity molecules using submicron beads, including those for organic receptor analysis and refining. The program for development and research of fixation technology develops immobilizing reaction and latex particle having cleavable linker, and synthesize small molecules for the identification of target receptors. The program for development of organic receptor refining technology directly refines cisplatin-telomere binding proteins from crude nuclear extracts of HeLa, and analyzes them; analyzes the functions of Ref-1 purified from Jurkat cell nuclear extracts as the binding protein for drug E3330 which specifically controls the transcriptive factor NF-{kappa}B; and studies LK6A having an MLR inhibiting activity, promoters for production of Alendronate, Taxol and leptin, D91-6092 as a promising anti-cancer agent, and antirheumatic, antiallergic, antitumor agents and FK506 as immunosuppressant agent. (NEDO)

  19. Synthesis and mechanical properties of silicon-doped TiAl-alloys with grain sizes in the submicron range; Herstellung und mechanische Eigenschaften silizidhaltiger TiAl-Werkstoffe mit Korngroessen im Submikronbereich

    Energy Technology Data Exchange (ETDEWEB)

    Bohn, R. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Werkstofforschung

    1999-07-01

    The objective of this study is to provide a comprehensive insight into the mechanical properties of nano- and submicron-grained intermetallics, containing ceramic particles as a second phase. The investigations are focussed on {gamma}-TiAl-based alloys with a fine dispersion of titanium silicides. The samples are prepared by high energy milling and subsequent hot isostatic pressing. The mechanical properties are mainly dominated by the grain size as the most important structural feature. At room temperature, the grain size dependence of hardness and yield strength can be described by the well-known Hall-Petch relationship. Contrary to the behavior of conventional alloys, the ductility of submicron-grained alloys drops if the grain size is further reduced. This may be attributed to the insignificance of diffusional creep at room temperature and to arising difficulties evolving for dislocation-based deformation mechanisms. In the high temperature range, the flow stress is strongly reduced. Superplastic deformation becomes feasible already at 800 C. The silicide particles impede grain growth, but they also promote cavitation during tensile straining. The mechanisms of deformation are similar to those established for coarse-grained materials at higher temperatures ({>=}1000 C). (orig.)

  20. Velocity overshoot decay mechanisms in compound semiconductor field-effect transistors with a submicron characteristic length

    Directory of Open Access Journals (Sweden)

    Jang Jyegal

    2015-06-01

    Full Text Available Velocity overshoot is a critically important nonstationary effect utilized for the enhanced performance of submicron field-effect devices fabricated with high-electron-mobility compound semiconductors. However, the physical mechanisms of velocity overshoot decay dynamics in the devices are not known in detail. Therefore, a numerical analysis is conducted typically for a submicron GaAs metal-semiconductor field-effect transistor in order to elucidate the physical mechanisms. It is found that there exist three different mechanisms, depending on device bias conditions. Specifically, at large drain biases corresponding to the saturation drain current (dc region, the velocity overshoot suddenly begins to drop very sensitively due to the onset of a rapid decrease of the momentum relaxation time, not the mobility, arising from the effect of velocity-randomizing intervalley scattering. It then continues to drop rapidly and decays completely by severe mobility reduction due to intervalley scattering. On the other hand, at small drain biases corresponding to the linear dc region, the velocity overshoot suddenly begins to drop very sensitively due to the onset of a rapid increase of thermal energy diffusion by electrons in the channel of the gate. It then continues to drop rapidly for a certain channel distance due to the increasing thermal energy diffusion effect, and later completely decays by a sharply decreasing electric field. Moreover, at drain biases close to a dc saturation voltage, the mechanism is a mixture of the above two bias conditions. It is suggested that a large secondary-valley energy separation is essential to increase the performance of submicron devices.

  1. Functional organization of the HIV lipid envelope

    Science.gov (United States)

    Huarte, Nerea; Carravilla, Pablo; Cruz, Antonio; Lorizate, Maier; Nieto-Garai, Jon A.; Kräusslich, Hans-Georg; Pérez-Gil, Jesús; Requejo-Isidro, Jose; Nieva, José L.

    2016-01-01

    The chemical composition of the human immunodeficiency virus type 1 (HIV-1) membrane is critical for fusion and entry into target cells, suggesting that preservation of a functional lipid bilayer organization may be required for efficient infection. HIV-1 acquires its envelope from the host cell plasma membrane at sites enriched in raft-type lipids. Furthermore, infectious particles display aminophospholipids on their surface, indicative of dissipation of the inter-leaflet lipid asymmetry metabolically generated at cellular membranes. By combining two-photon excited Laurdan fluorescence imaging and atomic force microscopy, we have obtained unprecedented insights into the phase state of membranes reconstituted from viral lipids (i.e., extracted from infectious HIV-1 particles), established the role played by the different specimens in the mixtures, and characterized the effects of membrane-active virucidal agents on membrane organization. In determining the molecular basis underlying lipid packing and lateral heterogeneity of the HIV-1 membrane, our results may help develop compounds with antiviral activity acting by perturbing the functional organization of the lipid envelope. PMID:27678107

  2. Submicron Schottky-gate field-effect transistors - a new elemental base for microwave integrated microcircuits

    Energy Technology Data Exchange (ETDEWEB)

    Tolstoi, A.I.; Petrov, G.V.; Batura, V.G.; Bosyi, V.I.

    1986-03-01

    The authors analyze the present level of development of submicron semiconducting devices in order to systematize the available information, point out existing problems, and provide a foundation for methods for avoiding these problems. The authors specify the following methods: (1) structural - decreasing the dimensions of the active regions should further increase the limiting frequencies, decrease the noise factor, and increase the gain; (2) choice of semiconducting material - the use of semiconductors with higher charge-carrier mobility will improve the limiting frequencies, gain, and noise factor and affect the choice of structure of the semiconducting device.

  3. Two-photon laser fabrication of three-dimensional silver microstructures with submicron scale linewidth

    Energy Technology Data Exchange (ETDEWEB)

    Tsutsumi, Naoto; Nagata, Kazuya; Sakai, Wataru [Kyoto Institute of Technology, Department of Macromolecular Science and Engineering, Graduate School of Science and Technology, Kyoto (Japan)

    2011-05-15

    We show three-dimensional silver microstructures with a submicron scale linewidth fabricated via two-photon photoreduction of silver ions in a poly(N-vinylpyrrolidone) (PVP) matrix. Femtosecond laser at 508 nm directly excites the carbonyl group of PVP via two-photon excitation to reduce silver ions. Lone pair electrons in PVP stabilized silver ions and lower molecular weight of PVP prevented silver clusters growing larger. The effect of molecular weight of PVP on linewidth of silver nanowire is investigated. (orig.)

  4. Phase Evolution during the Sintering of Submicron Ti(C,N)-Based Cermets

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The submicron powder mixtures of TiC-TiN-WC-Mo-C-Ni sintered at 1400℃ or below in vacuum were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses. The results showed that Mo2C formed at 800℃ or below. Both WC and Mo2C disappeared at 1200℃, and TiN disappeared at 1250℃. In addition, the variations of lattice constants of the titanium carbonitride and nickel binder phase with sintering temperature were experimentally obtained, and the reason was analyzed.

  5. Infrared Luminescent Properties of a Pr-Doped KBr Submicron Rod

    Institute of Scientific and Technical Information of China (English)

    WEI Feng-Wei; ZHANG Xiao-Song; LI Lan; XU Jian-Ping; ZHOU Yong-Liang; LIU Pei

    2011-01-01

    KBr:Pr with a submicron rod structure is successfully synthesized by a solid-state reaction using absolute alcohol as the abrasive. X-ray diffraction,scanning electron microscopy,photoluminescence spectra and fluorescence decay curves are used to characterize the resulting materials.The influences of Pr3+ dopant concentration on the luminescence and lifetime are discussed.Furthermore,luminescent measurements show that KBr:Pr has a high emission intensity compared with other Pr-doped matrixes,which is related to the low phonon energy of KBr.The results suggest that the phonon energy of the host is important in determining the luminescent efficiency.

  6. Novel deep—submicron x—ray lithography process for T—shaped gate patterns

    Institute of Scientific and Technical Information of China (English)

    XieChangqing; YiFuting; 等

    2001-01-01

    The growing interest in the use of Gallium Arsenids semiconductor materials has presented many opportunities for device operational speed improvements but has also presented many problems for the device maker,A novel deep-submicron x-ray lithography process for T-shaped gate patterns useful for high-electron-mobility transistors(HEMT) is introduced in this work.In the fabrication of T-shaped gate a therr layer resists method is used.The x-ray exposure experiments were finished by Beijing Synchrotron Radiation Facility(BSRF) 3B1A beamline,and good result has been obtained.

  7. Measurement of focusing properties for high numerical aperture optics using an automated submicron beamprofiler

    CERN Document Server

    Chapman, J J; Streed, E W; Kielpinski, D

    2007-01-01

    The focusing properties of three aspheric lenses with numerical aperture (NA) between 0.53 and 0.68 were directly measured using an interferometrically referenced scanning knife-edge beam profiler with sub-micron resolution. The results obtained for two of the three lenses tested were in agreement with paraxial gaussian beam theory. It was also found that the highest NA aspheric lens which was designed for 830nm was not diffraction limited at 633nm. This process was automated using motorized translation stages and provides a direct method for testing the design specifications of high numerical aperture optics.

  8. Diazepam submicron emulsions containing soya-bean oil and intended for oral or rectal delivery.

    Science.gov (United States)

    Gajewska, M; Sznitowska, M; Janicki, S

    2001-03-01

    Physically stable diazepam submicron emulsions were prepared using soya-bean oil. Diazepam concentration 4 mg/ml, suitable for rectal or oral delivery, was achieved in 20% emulsions. Mixture of egg lecithin (1.2%) and poloxamer (2.0%) has been chosen as the most suitable emulsifying agent. Composition of the emulsion may be supplemented with alpha-tocopherol and parabens. However, the system was not stable when either phenylethanol or chlorhexidine gluconate was added. Taste masking agents commonly used as food additives decreased stability of the preparation and were not efficient in elimination of a bitter taste of the drug-loaded emulsions.

  9. Analysis and Design of Monolithic Inductors in Sub-micron CMOS

    DEFF Research Database (Denmark)

    Fallesen, Carsten; Jørgensen, Allan

    1997-01-01

    In the last few years the CMOS processes have gone into deep sub-micron channel lengths. This means that it is now possible to make GHz applications in CMOS. In analog GHz applications it is often necessary to have access to inductors. This report describes the development of a physical model...... for optimization. To verify the model more than 40 inductors have been produced and their performance have been measured. The produced inductors sweep a number of design parameters of the inductors, in order to get a realistic dataset. The produced inductors have inductances values of 2 nH to 10 nH, resonance...

  10. Methodology of Efficient Energy Design for Noisy Deep Submicron VLSI Chips

    Institute of Scientific and Technical Information of China (English)

    WANGJun

    2004-01-01

    Power dissipation is becoming increasingly important as technology continues to scale. This paper describes a way to consider the dynamic, static and shortcircuit power dissipation simultaneously for making complete, quantitative prediction on the total power dissipation of noisy VLSI chip. Especially, this new method elucidates the mechanism of power dissipation caused by the intrinsic noise of deep submicron VLSI chip. To capture the noise dependency of efficient energy design strategies for VLSI chip, the simulation of two illustrative cases are observed. Finally, the future works are proposed for the optimum tradeoff among the power, speed and area, which includes the use of floating-body partially depleted silicon-on-insulator CMOS technology.

  11. Suppression of transient enhanced diffusion in sub-micron patterned silicon template by dislocation loops formation

    Science.gov (United States)

    Hu, Kuan-Kan; Chang, Ruey-Dar; Woon, Wei Yen

    2015-10-01

    We investigate the evolution of two dimensional transient enhanced diffusion (TED) of phosphorus in sub-micron scale patterned silicon template. Samples doped with low dose phosphorus with and without high dose silicon self-implantation, were annealed for various durations. Dopant diffusion is probed with plane-view scanning capacitance microscopy. The measurement revealed two phases of TED. Significant suppression in the second phase TED is observed for samples with high dose self-implantation. Transmission electron microscopy suggests the suppressed TED is related to the evolution of end of range defect formed around ion implantation sidewalls.

  12. Suppression of transient enhanced diffusion in sub-micron patterned silicon template by dislocation loops formation

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Kuan-Kan; Woon, Wei Yen [Department of Physics, National Central University, Jungli, 32054, Taiwan (China); Chang, Ruey-Dar [Chang Gung University, Taoyuan, Taiwan 33302 (China)

    2015-10-15

    We investigate the evolution of two dimensional transient enhanced diffusion (TED) of phosphorus in sub-micron scale patterned silicon template. Samples doped with low dose phosphorus with and without high dose silicon self-implantation, were annealed for various durations. Dopant diffusion is probed with plane-view scanning capacitance microscopy. The measurement revealed two phases of TED. Significant suppression in the second phase TED is observed for samples with high dose self-implantation. Transmission electron microscopy suggests the suppressed TED is related to the evolution of end of range defect formed around ion implantation sidewalls.

  13. Suppression of transient enhanced diffusion in sub-micron patterned silicon template by dislocation loops formation

    Directory of Open Access Journals (Sweden)

    Kuan-Kan Hu

    2015-10-01

    Full Text Available We investigate the evolution of two dimensional transient enhanced diffusion (TED of phosphorus in sub-micron scale patterned silicon template. Samples doped with low dose phosphorus with and without high dose silicon self-implantation, were annealed for various durations. Dopant diffusion is probed with plane-view scanning capacitance microscopy. The measurement revealed two phases of TED. Significant suppression in the second phase TED is observed for samples with high dose self-implantation. Transmission electron microscopy suggests the suppressed TED is related to the evolution of end of range defect formed around ion implantation sidewalls.

  14. Submicron-scale manipulation of phase separation in organic solar cells

    Science.gov (United States)

    Chen, Fang-Chung; Lin, Yi-Kai; Ko, Chu-Jung

    2008-01-01

    This paper describes a method for controlling the submicron-scale phase separation of poly(3-hexylthiophene) and (6,6)-phenyl-C61-butyric acid methyl ester in organic solar cells. Using microcontact printing of self-assembled monolayers on the device buffer layer to divide the surface into two regimes having different surface energies, an interdigitated structure aligned vertical to the substrate surface is achieved after spontaneous surface-directed phase separation. The power conversion efficiency increases upon decreasing the grating spacing, reaching 2.47%. The hole mobility increased as a consequence of improved polymer chain ordering, resulting in higher device efficiency, while smaller pattern sizes were used.

  15. IR Drop Analysis and Its Reduction Techniques in Deep Submicron Technology

    Directory of Open Access Journals (Sweden)

    Vanpreet Kaur

    2015-01-01

    Full Text Available This paper presents a detailed conceptual analysis of IR Drop effect in deep submicron technologies and its reduction techniques. The IR Drop effect in power/ground network increases rapidly with technology scaling. This affects the timing of the design and hence the desired speed. It is shown that in present day designs, using well known reduction techniques such as wire sizing and decoupling capacitor insertion, may not be sufficient to limit the voltage fluctuations and hence, two more important methods such as selective glitch reduction technique and IR Drop reduction through combinational circuit partitioning are discussed and the issues related to all the techniques are revised.

  16. Binary lipids-based nanostructured lipid carriers for improved oral bioavailability of silymarin.

    Science.gov (United States)

    Shangguan, Mingzhu; Lu, Yi; Qi, Jianping; Han, Jin; Tian, Zhiqiang; Xie, Yunchang; Hu, Fuqiang; Yuan, Hailong; Wu, Wei

    2014-02-01

    The main purpose of this study was to prepare binary lipids-based nanostructured lipid carriers to improve the oral bioavailability of silymarin, a poorly water-soluble liver protectant. Silymarin-loaded nanostructured lipid carriers were prepared by the method of high-pressure homogenization with glycerol distearates (Precirol ATO-5) and oleic acid as the solid and liquid lipids, respectively, and lecithin (Lipoid E 100) and Tween-80 as the emulsifiers. The silymarin-nanostructured lipid carrier prepared under optimum conditions was spherical in shape with mean particle size of ∼78.87 nm, entrapment efficiency of 87.55%, loading capacity of 8.32%, and zeta potential of -65.3 mV, respectively. In vitro release of silymarin-nanostructured lipid carriers was very limited even after 12 h, while in vitro lipolysis showed fast digestion of nanostructured lipid carriers within 1 h. Relative oral bioavailability of silymarin-nanostructured lipid carriers in Beagle dogs was 2.54- and 3.10-fold that of marketed Legalon® and silymarin solid dispersion pellets, respectively. It was concluded that nanostructured lipid carriers were potential drug delivery systems to improve the bioavailability of silymarin. Other than improved dissolution, alternative mechanisms such as facilitated absorption as well as lymphatic transport may contribute to bioavailability enhancement.

  17. Theory of Kinetics of Registration and Anti-Registration in Lipid Bilayers

    Science.gov (United States)

    Olmsted, Peter; Williamson, John

    Lipid bilayer leaflets are often treated as if they are coupled; i.e., that the two leaflets undergo simultaneous transitions between phases, and that domains involve both leaflets together in a registered fashion. We present theory and simulation showing how interleaflet couplings and hydrophobic mismatch can lead to a complex phase diagram with multiple metastable two-phase and three-phase states. Many of these states can be discerned in the experimental literature, and are expected in the early stages of coarsening when domains are sub-micron (and thus perhaps of significance to lipid rafts). We present different kinetic scenarios for transitions between these state, and show how lipid flip flop can surprisingly lead to non-symmetric anti-registered patterns.

  18. Aerosol particles in the Mexican East Pacific Part I: processing and vertical redistribution by clouds

    Directory of Open Access Journals (Sweden)

    D. Baumgardner

    2005-01-01

    Full Text Available Airborne measurements of aerosol particle size distributions were made in the Mexican Intertropical Convergence Zone. The volume concentrations of submicron and super micron particles at cloud base were compared with those in near-cloud regions over a range of altitudes. Of 78 near-cloud regions analyzed, 68% and 45% had enhanced volumes of submicron particles and supermicron particles, respectively. In addition, 35% of these regions had supermicron particles removed, presumably by precipitation. In 61% of the cases the enhancement in volume occurred over the size range from 0.1 to 50 μm whereas only submicron volumes were enhanced in 35% of the cases. In regions near clouds that were formed in air of maritime origin the frequency of volume enhancement decreased with increasing altitude and was twice as frequent on the dissipating side of clouds compared to the growing side. No such differences were found in the regions near clouds formed in air originating from the land. The frequency and average magnitude of volume enhancement are in qualitative and quantitative agreement with previous observational and theoretical studies that relate enhancements in particle mass to the uptake by cloud droplets of SO2 accompanied by additional growth by droplet coalescence.

  19. Preparation of ultra-fine powders from polysaccharide-coated solid lipid nanoparticles and nanostructured lipid carriers by innovative nano spray drying technology.

    Science.gov (United States)

    Wang, Taoran; Hu, Qiaobin; Zhou, Mingyong; Xue, Jingyi; Luo, Yangchao

    2016-09-10

    In this study, five polysaccharides were applied as natural polymeric coating materials to prepare solid lipid nanoparticles (SLN) and nanostructure lipid carriers (NLC), and then the obtained lipid colloidal particles were transformed to solid powders by the innovative nano spray drying technology. The feasibility and suitability of this new technology to generate ultra-fine lipid powder particles were evaluated and the formulation was optimized. The spray dried SLN powder exhibited the aggregated and irregular shape and dimension, but small, uniform, well-separated spherical powder particles of was obtained from NLC. The optimal formulation of NLC was prepared by a 20-30% oleic acid content with carrageenan or pectin as coating material. Therefore, nano spray drying technology has a potential application to produce uniform, spherical, and sub-microscale lipid powder particles when the formulation of lipid delivery system is appropriately designed. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. X-ray Fluorescence Tomography of Aged Fluid-Catalytic-Cracking Catalyst Particles Reveals Insight into Metal Deposition Processes

    NARCIS (Netherlands)

    Kalirai, Samanbir; Boesenberg, Ulrike; Falkenberg, Gerald; Meirer, Florian; Weckhuysen, Bert M.

    2015-01-01

    Microprobe X-ray fluorescence tomography was used to investigate metal poison deposition in individual, intact and industrially deactivated fluid catalytic cracking (FCC) particles at two differing catalytic life-stages. 3D multi-element imaging, at submicron resolution was achieved by using a large

  1. X-ray Fluorescence Tomography of Aged Fluid-Catalytic-Cracking Catalyst Particles Reveals Insight into Metal Deposition Processes

    NARCIS (Netherlands)

    Kalirai, Samanbir; Boesenberg, Ulrike; Falkenberg, Gerald; Meirer, Florian; Weckhuysen, Bert M.

    2015-01-01

    Microprobe X-ray fluorescence tomography was used to investigate metal poison deposition in individual, intact and industrially deactivated fluid catalytic cracking (FCC) particles at two differing catalytic life-stages. 3D multi-element imaging, at submicron resolution was achieved by using a

  2. In situ visualisation and characterisation of the capacity of highly reactive minerals to preserve soil organic matter (SOM) in colloids at submicron scale.

    Science.gov (United States)

    Xiao, Jian; Wen, Yongli; Li, Huan; Hao, Jialong; Shen, Qirong; Ran, Wei; Mei, Xinlan; He, Xinhua; Yu, Guanghui

    2015-11-01

    Mineral-organo associations (MOAs) are a mixture of identifiable biopolymers associated with highly reactive minerals and microorganisms. However, the in situ characterization and correlation between soil organic matter (SOM) and highly reactive Al and Fe minerals are still unclear for the lack of technologies, particularly in the long-term agricultural soil colloids at submicron scale. We combined several novel techniques, including nano-scale secondary ion mass spectrometry (NanoSIMS), X-ray absorption near edge structure (XANES) and confocal laser scanning microscopy (CLSM) to characterise the capacity of highly reactive Al and Fe minerals to preserve SOM in Ferralic Cambisol in south China. Our results demonstrated that: (1) highly reactive minerals were strongly related to SOM preservation, while SOM had a more significant line correlation with the highly reactive Al minerals than the highly reactive Fe minerals, according to the regions of interest correlation analyses using NanoSIMS; (2) allophane and ferrihydrite were the potential mineral species to determine the SOM preservation capability, which was evaluated by the X-ray photoelectron spectroscopy (XPS) and Fe K-edge XANES spectroscopy techniques; and (3) soil organic biopolymers with dominant compounds, such as proteins, polysaccharides and lipids, were distributed at the rough and clustered surface of MOAs with high chemical and spatial heterogeneity according to the CLSM observation. Our results also promoted the understanding of the roles played by the highly reactive Al and Fe minerals in the spatial distribution of soil organic biopolymers and SOM sequestration.

  3. Nano/submicron-scale TiO{sub 2} network on titanium surface for dental implant application

    Energy Technology Data Exchange (ETDEWEB)

    Yang, W.-E. [Institute of Oral Biology, National Yang-Ming University, Taipei, Taiwan (China); Hsu, M.-L.; Lin, M.-C. [Department of Dentistry, National Yang-Ming University, Taipei, Taiwan (China); Chen, Z.-H. [Institute of Oral Biology, National Yang-Ming University, Taipei, Taiwan (China); Chen, L.-K. [Department of Dentistry, Taipei City Hospital, Taipei, Taiwan (China); Huang, H.-H. [Institute of Oral Biology, National Yang-Ming University, Taipei, Taiwan (China); Department of Dentistry, National Yang-Ming University, Taipei, Taiwan (China); Department of Dentistry, Taipei City Hospital, Taipei, Taiwan (China)], E-mail: hhhuang@ym.edu.tw

    2009-06-24

    In this study, a fast electrochemical anodization treatment, applying different anodic currents, was used to produce a nano/submicron-scale network oxide layer on Ti metal surface for biomedical implant application. The anodized Ti surface was analyzed using thin film X-ray diffractometer, X-ray photoelectron spectrometer, and field emission scanning electron microscope. The whole blood coagulation and human bone marrow stem cells (hBMSCs) adhesion on the anodized Ti surface were evaluated. Results showed that a nano/submicron-scale TiO{sub 2} network layer with a lateral pore size of 20-160 nm could be rapidly produced on Ti surface through electrochemical anodization treatment. Increasing the applied anodic current led to an increase in pore size of TiO{sub 2} network. The nano/submicron-scale TiO{sub 2} network layer significantly enhanced the whole blood coagulation and hBMSCs adhesion on Ti surface.

  4. Doxorubicin Lipid Complex Injection

    Science.gov (United States)

    Doxorubicin lipid complex is used to treat ovarian cancer that has not improved or that has worsened after treatment with other medications. Doxorubicin lipid complex is also used to treat Kaposi's ...

  5. Irinotecan Lipid Complex Injection

    Science.gov (United States)

    Irinotecan lipid complex is used in combination with other medications to treat pancreatic cancer that has spread to other ... worsened after treatment with other chemotherapy medications. Irinotecan lipid complex is in a class of antineoplastic medications ...

  6. Daunorubicin Lipid Complex Injection

    Science.gov (United States)

    Daunorubicin lipid complex is used to treat advanced Kaposi's sarcoma (a type of cancer that causes abnormal tissue to ... body) related to acquired immunodeficiency syndrome (AIDS). Daunorubicin lipid complex is in a class of medications called ...

  7. Vincristine Lipid Complex Injection

    Science.gov (United States)

    Vincristine lipid complex is used to treat a certain type of acute lymphoblastic leukemia (ALL; a type of cancer ... least two different treatments with other medications. Vincristine lipid complex is in a class of medications called ...

  8. Parenteral Nutrition and Lipids.

    Science.gov (United States)

    Raman, Maitreyi; Almutairdi, Abdulelah; Mulesa, Leanne; Alberda, Cathy; Beattie, Colleen; Gramlich, Leah

    2017-04-14

    Lipids have multiple physiological roles that are biologically vital. Soybean oil lipid emulsions have been the mainstay of parenteral nutrition lipid formulations for decades in North America. Utilizing intravenous lipid emulsions in parenteral nutrition has minimized the dependence on dextrose as a major source of nonprotein calories and prevents the clinical consequences of essential fatty acid deficiency. Emerging literature has indicated that there are benefits to utilizing alternative lipids such as olive/soy-based formulations, and combination lipids such as soy/MCT/olive/fish oil, compared with soybean based lipids, as they have less inflammatory properties, are immune modulating, have higher antioxidant content, decrease risk of cholestasis, and improve clinical outcomes in certain subgroups of patients. The objective of this article is to review the history of IVLE, their composition, the different generations of widely available IVLE, the variables to consider when selecting lipids, and the complications of IVLE and how to minimize them.

  9. SOLID LIPID NANOPARTICLES: AN ADVANCED DRUG DELIVERY SYSTEM

    Directory of Open Access Journals (Sweden)

    Raghu Nandan Reddy* and Arshia Shariff

    2013-01-01

    Full Text Available Solid lipid nanoparticles are at the forefront of the rapidly developing field of nanotechnology with several potential applications in drug delivery, research and clinical medicine, as well as in other varied sciences. Solid lipid nanoparticle (SLN dispersions have been proposed as a new type of colloidal drug carrier system suitable for intravenous administration. Solid lipid nanoparticles (SLNs technology represents a promising new approach to lipophilic drug delivery. Solid lipid nanoparticles are spherical lipid particles ranging in size from 1 to 1000 nm and are dispersed in water or in aqueous surfactant solution. It is identical to an oil-in-water emulsion, but the liquid lipid (oil of the emulsion has been replaced by a solid lipid, i.e., yielding Solid Lipid Nanoparticles. SLN are particles made from solid lipid or lipid blends produced by high pressure homogenization. The biodegradable and bioacceptable nature of SLNs makes them less toxic as compared to polymeric nanoparticles. SLNs can also be used to improve the bioavailability of drugs. In this present review this new approach is discussed in terms of their advantages, disadvantages, methods, characterization, pharmacokinetic studies, in-vivo studies, in-vitro studies, and special features

  10. On the sub-micron aerosol size distribution in a coastal-rural site at El Arenosillo Station (SW-Spain

    Directory of Open Access Journals (Sweden)

    M. Sorribas

    2011-02-01

    Full Text Available This study is focused on the analysis of the sub-micron aerosol characteristics at rural and coastal environment in Southwestern Spain. Particle number size distributions were measured in the size range (14–673 nm using a Scanning Mobility Particle Sizer (SMPS, Model 3936-TSI, from 15 July 2004 to 31 July 2006 at El Arenosillo Station. Mean total concentration was 8660 cm−3 and mean concentrations for the nucleation, Aitken and accumulation modes particles were 2830 cm−3, 4110 cm−3 and 1720 cm−3, respectively. Mean geometric diameters of the four modes particles, which characterized the mean size distribution per month, were about 16 nm, 42 nm, 103 nm and 237 nm. Two kinds of episodes produced a maximum of the total concentration around noon: the new particle formation and the regional recirculation such as the sea-land breeze. Two types of nucleation events (called N$1 and N2 were observed. Events N1 were an example of the influence of regional sources and Events N2 showed the weight of local industries over the rural and coastal background levels. The 60% of nucleation events were related to NE and NW wind sectors (N1 and N2 respectively, a ΔT higher than 12 °C, a wind speed higher than 2.3 m s−1 and a total surface area for the accumulation mode particles below of 11 190 μ m2 cm−3. The influence of the sea-land breeze processes has been analyzed, observing increases of up to 50%, 110% and 90% of the particle concentration for the nucleation, Aitken and accumulation modes. Annual evolution of monthly averages allowed to conclude that the increase or decrease of 1 cm−3 of the concentration for nucleation mode particles was related to opposite trend of 0.5 cm−3 of the concentration for accumulation mode. This anti-correlation produced a weak seasonal

  11. Design of lipid microparticle dispersions based on the physicochemical properties of the lipid and aqueous phase.

    Science.gov (United States)

    Lauterbach, Andreas; Müller-Goymann, Christel C

    2015-10-15

    Lipid microparticle (LMP) dispersions may be utilized as novel pharmaceutical dosage forms for different administration routes. The particle size and particle size distribution of the LMPs can be classified to the most crucial specifications for therapeutical and research applications. The size parameters can be adjusted via the physicochemical properties of the inner lipid and the outer aqueous phase. In the present study, ten different solid lipids with incorporated lecithin and four concentrations of the surfactant poloxamer 407 (P407) were utilized for LMP dispersion preparation. Physicochemical properties of the bulk and dispersed lipid matrices as well as features of the P407 solutions were determined. Correlations between the mean particle size (mean) of the LMPs and the span as parameter for the particle size distribution as responses were identified by plotting against the measured physicochemical parameters. Most significant linear correlations were found between the mean and the micellization onset temperature (Tmicell) in the parent solution and the dynamic viscosity of the emulsifier solution at 25 °C and between the span and the Tmicell in the LMP dispersion. Consequently, P407 micelles as a reservoir for surfactant monomers and the overall viscosity as a separator between newly-formed lipid droplets are fundamental stabilizing parameters. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Static and dynamic properties of critical fluctuations in lipid bilayers

    Science.gov (United States)

    Honerkamp-Smith, Aurelia Rose

    A current popular view in cell biology is that sub-micron, dynamic heterogeneity in lipid and protein composition arises within the plasma membranes of resting cells. Local changes in membrane composition may affect protein activity, which is sensitive to the lipid environment. We have observed dynamic heterogeneity in lipid membranes in the form of composition fluctuations near a miscibility critical point. In this thesis we quantitatively describe the dynamic and static properties of these fluctuations. We evaluate the temperature dependence of line tension between liquid domains and of fluctuation correlation lengths in lipid membranes in order to extract a critical exponent, nu. We obtain nu = 1.2 +/- 0.2, consistent with the Ising model prediction nu = 1. From probability distributions of pixel intensities in fluorescence images of membranes, we also extract an independent critical exponent of beta = 0.124 +/- 0.03, which is consistent with the Ising prediction of beta = 1/8. We have systematically measured the effective dynamic critical exponent z eff in a lipid membrane while cooling the system toward a critical point. We observe that zeff slightly increases from a value of roughly 2.6 as xi → 0, to zeff = 3.0 +/- 0.15 at xi = 13 sm. Our measurements are consistent with the prediction that zeff → 3.00 as T → Tc for a 2-D system with conserved order parameter in contact with a bulk 3-D liquid. To our knowledge, no other systematic measurement of zeff with increasing xi exists for a 2-D system with conserved order parameter. We also report the solubility limit of several biologically relevant sterols in electroformed giant unilamellar vesicle membranes containing phosphatidylcholine (PC) lipids in ratios of 1:1:X DPPC:DOPC:sterol. We find solubility limits of cholesterol, lanosterol, ergosterol, stigmasterol, and beta-sitosterol using nuclear magnetic resonance.

  13. Role of free carriers excited by ultrafast Bessel beams for submicron structuring applications

    Science.gov (United States)

    Velpula, Praveen Kumar; Bhuyan, Manoj Kumar; Mauclair, Cyril; Colombier, Jean-Philippe; Stoian, Razvan

    2014-07-01

    Ultrafast Bessel beams are ideal sources for high aspect ratio submicron structuring applications because of their nondiffracting nature and higher stability in nonlinear propagation. We report here on the interaction of ultrafast Bessel beams at various laser energies and pulse durations with transparent materials (fused silica) and define their impact on photoinscription regimes, i.e., formation of positive and negative refractive index structures. The laser pulse duration was observed to be key in deciding the type of the structures via excitation efficiency. To understand the relevant mechanisms for forming these different structures, the free carrier behavior as a function of laser pulse duration and energy was studied by capturing instantaneous excitation profiles using time-resolved microscopy. Time-resolved imaging and simulation studies reveal that low carrier densities are generated for ultrashort pulses, leading to soft positive index alterations via presumably nonthermally induced structural transitions involving defects. On the other hand, the high free carrier density generation in the case of longer pulse durations leads to hydrodynamic expansion, resulting in high aspect ratio submicron-size wide voids. Delayed ionization, carrier defocusing, and lower nonlinear effects are responsible for the confinement of energy, resulting in efficient energy deposition on-axis.

  14. The efficiency and stability of bubble formation by acoustic vaporization of submicron perfluorocarbon droplets.

    Science.gov (United States)

    Reznik, Nikita; Shpak, Oleksandr; Gelderblom, Erik C; Williams, Ross; de Jong, Nico; Versluis, Michel; Burns, Peter N

    2013-09-01

    Submicron droplets of liquid perfluorocarbon converted into microbubbles with applied ultrasound have been studied, for a number of years, as potential next generation extravascular ultrasound contrast agents. In this work, we conduct an initial ultra-high-speed optical imaging study to examine the vaporization of submicron droplets and observe the newly created microbubbles in the first microseconds after vaporization. It was estimated that single pulses of ultrasound at 10 MHz with pressures within the diagnostic range are able to vaporize on the order of at least 10% of the exposed droplets. However, only part of the newly created microbubbles survives immediately following vaporization - the bubbles may recondense back into the liquid droplet state within microseconds of nucleation. The probability of bubble survival within the first microseconds of vaporization was shown to depend on ultrasound excitation pressure as well as on bubble coalescence during vaporization, a behavior influenced by the presence of coating material on the newly created bubbles. The results of this study show for the first time that although initial vaporization of droplets is necessary to create echogenic bubbles, additional factors, such as coalescence and bubble shell properties, are important and should be carefully considered for the production of microbubbles for use in medical imaging.

  15. Hybridization between nanocavities for a polarimetric color sorter at the sub-micron scale.

    Science.gov (United States)

    Segal, Elad; Weissman, Adam; Gachet, David; Salomon, Adi

    2016-08-18

    Metallic hole arrays have been recently used for color generation and filtering due to their reliability and color tunability. However, color generation is still limited to several microns. Understanding the interaction between the individual elements of the whole nanostructure may push the resolution to the sub-micron level. Herein, we study the hybridization between silver nanocavities in order to obtain active color generation at the micron scale. To do so, we use five identical triangular cavities which are separated by hundreds of nanometers from each other. By tuning either the distance between the cavities or the optical polarization state of the incoming field, the transmitted light through the cavities is actively enhanced at specific frequencies. Consequently, a rainbow of colors is observed from a sub-micron scale unit. The reason for this is that the metallic surface plays a vital role in the hybridization between the cavities and contributes to higher frequency modes. Cathodoluminescence measurements have confirmed this assumption and have revealed that these five triangular cavities act as a unified entity surrounded by the propagated surface plasmons. In such plasmonic structures, multi-color tuning can be accomplished and may open the possibility to improve color generation and high-quality pixel fabrication.

  16. Low-cost replication of self-organized sub-micron structures into polymer films

    Directory of Open Access Journals (Sweden)

    H. Stenberg

    2015-02-01

    Full Text Available In this paper, the results of exploiting self-organized sub-micron polystyrene (PS wrinkle patterns possessing random orientation, in preparation of a nickel stamp for hot embossing purposes, are presented. Self-organized patterns were prepared employing a method in which a stiff cross-linked capping layer on the topmost part of the soft polystyrene layer was created by using reactive ion etching (RIE device with mild conditions and argon as a process gas, and the wrinkle formation was initiated thermally. Different surface patternings were obtained using silicon and stainless steel (SST wafers as substrates. Prepared Ni-stamps were employed in hot embossing of polycarbonate (PC and cyclo-olefin polymer (COP films, using a nano-imprinting process. The replication quality of the self-organized wrinkle structures in PC and COP films was monitored by comparing the shape and dimensions of the original and final surface structures. The hot embossed sub-micron scale features, originally formed on stainless steel substrate, were found to have influence on the optical properties of the PC and COP films by lowering their reflectances.

  17. Effects of deformation on microstructures and properties of submicron crystalline Cu-5%Cr alloy

    Institute of Scientific and Technical Information of China (English)

    HE Wen-xiong; WANG Er-de; CHEN Hui; YU Yang; LIU Jing-lei

    2007-01-01

    Warm extrusion of submicron crystalline Cu-5%Cr from 100 ℃ to 600 ℃ was investigated. The effects of different extrusion ratios and different extrusion temperatures on microstructures and properties of submicron crystalline Cu-5%Cr were studied. The microstructures of the extruded Cu-5%Cr were characterized by backscattered electron images(BSE) and transmission electron microscopy(TEM). The mechanical properties of the extruded Cu-5%Cr were measured by means of microhardness and tension test. The results show that, the deformation, dynamic recovery and dynamic recrystallization of the extruded Cu-5%Cr are mainly produced in Cu matrix. The higher extrusion ratio leads to more uniform microstructure and finer Cu grains. When being extruded in the range of 100-600 ℃, dynamic recovery of Cu is the dominant process, and dynamic recrystallization of Cu occurred above 300 ℃ is far from end. The most part of microstructure of as-extruded Cu-5%Cr is subcrystallines produced by dynamic recovery, only a few recrystallines exist, and the average size of these grains is not larger than 400 nm. With extrusion temperature rising, the tensile strength and microhardness of Cu-5%Cr decrease, and elongation increases gradually.

  18. Development of eco-friendly submicron emulsions stabilized by a bio-derived gum.

    Science.gov (United States)

    Pérez-Mosqueda, Luis María; Ramírez, Pablo; Trujillo-Cayado, Luis Alfonso; Santos, Jenifer; Muñoz, José

    2014-11-01

    Many traditional organic solvents are being gradually replaced by ecofriendly alternatives. D-Limonene is a terpenic (bio)-solvent that fulfils the requirements to be considered a green solvent. D-Limonene sub-micron emulsions suffer from Ostwald ripening destabilization. In this study, we examined the influence of the addition of a natural gum (rosin gum) to D-limonene in order to prevent Ostwald ripening. This contribution deals with the study of emulsions formulated with a mixture of D-limonene and rosin gum as dispersed phase and Pluronic PE9400 as emulsifier. The procedure followed for the development of these formulations was based on the application of product design principles. This led to the optimum ratio rosin gum/D-limonene and subsequently to the optimum surfactant concentration. The combination of different techniques (rheology, laser diffraction and multiple light scattering) was demonstrated to be a powerful tool to assist in the prediction of the emulsions destabilization process. Not only did the addition of rosin gum highly increase the stability of these emulsions by inhibiting the Ostwald ripening, but it also reduced the emulsions droplet size. Thus, we found that stable sub-micron D-limonene-in-water emulsions have been obtained in the range 3-6 wt% Pluronic PE-9400 by means of a single-step rotor/stator homogenizing process.

  19. Investigations of micron and submicron wear features of diseased human cartilage surfaces.

    Science.gov (United States)

    Peng, Zhongxiao; Baena, Juan C; Wang, Meiling

    2015-02-01

    Osteoarthritis is a common disease. However, its causes and morphological features of diseased cartilage surfaces are not well understood. The purposes of this research were (a) to develop quantitative surface characterization techniques to study human cartilages at a micron and submicron scale and (b) to investigate distinctive changes in the surface morphologies and biomechanical properties of the cartilages in different osteoarthritis grades. Diseased cartilage samples collected from osteoarthritis patients were prepared for image acquisition using two different techniques, that is, laser scanning microscopy at a micrometer scale and atomic force microscopy at a nanometer scale. Three-dimensional, digital images of human cartilages were processed and analyzed quantitatively. This study has demonstrated that high-quality three-dimensional images of human cartilage surfaces could be obtained in a hydrated condition using laser scanning microscopy and atomic force microscopy. Based on the numerical data extracted from improved image quality and quantity, it has been found that osteoarthritis evolution can be identified by specific surface features at the micrometer scale, and these features are amplitude and functional property related. At the submicron level, the spatial features of the surfaces were revealed to differ between early and advanced osteoarthritis grades. The effective indentation moduli of human cartilages effectively revealed the cartilage deterioration. The imaging acquisition and numerical analysis methods established allow quantitative studies of distinctive changes in cartilage surface characteristics and better understanding of the cartilage degradation process.

  20. Laser smoothing of sub-micron grooves in hydroxyl-rich fused silica

    Energy Technology Data Exchange (ETDEWEB)

    Shen, N; Matthews, M J; Fair, J E; Britten, J A; Nguyen, H T; Cooke, D; Elhadj, S; Yang, S T

    2009-10-30

    Nano- to micrometer-sized surface defects on UV-grade fused silica surfaces are known to be effectively smoothed through the use of high-temperature localized CO{sub 2} laser heating, thereby enhancing optical properties. However, the details of the mass transport and the effect of hydroxyl content on the laser smoothing of defective silica at submicron length scales is still not completely understood. In this study, we examine the morphological evolution of sub-micron, dry-etched periodic surface structures on type II and type III SiO{sub 2} substrates under 10.6 {micro}m CO{sub 2} laser irradiation using atomic force microscopy (AFM). In-situ thermal imaging was used to map the transient temperature field across the heated region, allowing assessment of the T-dependent mass transport mechanisms under different laser-heating conditions. Computational fluid dynamics simulations correlated well with experimental results, and showed that for large effective capillary numbers (N{sub c} > 2), surface diffusion is negligible and smoothing is dictated by capillary action, despite the relatively small spatial scales studied here. Extracted viscosity values over 1700-2000K were higher than the predicted bulk values, but were consistent with the surface depletion of OH groups, which was confirmed using confocal Raman microscopy.

  1. Dynamics of submicron aerosol droplets in a robust optical trap formed by multiple Bessel beams

    Energy Technology Data Exchange (ETDEWEB)

    Thanopulos, Ioannis [Laboratory of Physical Chemistry, Vladimir-Prelog-Weg 2, ETH Zurich, CH-8093 Zurich (Switzerland); Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, Athens 11635 (Greece); Luckhaus, David; Signorell, Ruth, E-mail: rsignorell@ethz.ch [Laboratory of Physical Chemistry, Vladimir-Prelog-Weg 2, ETH Zurich, CH-8093 Zurich (Switzerland); Preston, Thomas C. [School of Chemistry, University of Bristol, Cantock' s Close, Clifton, Bristol BS8 1TS (United Kingdom)

    2014-04-21

    In this paper, we model the three-dimensional escape dynamics of single submicron-sized aerosol droplets in optical multiple Bessel beam traps. Trapping in counter-propagating Bessel beams (CPBBs) is compared with a newly proposed quadruple Bessel beam (QBB) trap, which consists of two perpendicularly arranged CPBB traps. Calculations are performed for perfectly and imperfectly aligned traps. Mie-theory and finite-difference time-domain methods are used to calculate the optical forces. The droplet escape kinetics are obtained from the solution of the Langevin equation using a Verlet algorithm. Provided the traps are perfectly aligned, the calculations indicate very long lifetimes for droplets trapped either in the CPBB or in the QBB trap. However, minor misalignments that are hard to control experimentally already severely diminish the stability of the CPBB trap. By contrast, such minor misalignments hardly affect the extended droplet lifetimes in a QBB trap. The QBB trap is found to be a stable, robust optical trap, which should enable the experimental investigation of submicron droplets with radii down to 100 nm. Optical binding between two droplets and its potential role in preventing coagulation when loading a CPBB trap is briefly addressed.

  2. Mechanisms of submicron inclusion re-equilibration during host mineral deformation

    Science.gov (United States)

    Griffiths, Thomas; Habler, Gerlinde; Abart, Rainer; Rhede, Dieter; Wirth, Richard

    2014-05-01

    Both brittle and ductile deformation can facilitate re-equilibration of mineral inclusions. The presence of inclusions also influences stress and strain distribution in the host. The processes governing feedbacks between brittle deformation, ductile deformation, and inclusion re-equilibration have been studied using unique microstructures in Permian meta-pegmatite garnets from the Koralpe, Eastern Alps, Austria. Sampled almandine-spessartine garnets contain highly abundant submicron-sized inclusions, which originated during or subsequent to magmatic garnet growth. The Permian magmatic assemblages were affected by eclogite facies metamorphism during the Cretaceous tectono-metamorphic event. The meta-pegmatite garnet deformed crystal-plastically at this metamorphic stage (Bestmann et al. 2008) and the host-inclusion system was affected by partial recrystallization. Trails of coarser inclusions (1-10µm diameter) crosscut the magmatic submicron inclusion density zoning in the garnet, defining curviplanar geometrical surfaces in 3D. In 10-40µm broad 'bleaching zones' flanking inclusion trails, the original ≤1µm sized inclusions are not seen in the optical microscope or SEM, however inclusions crystal axes is observed in connection with some already coarsened inclusions. Strain concentrations are widespread in some trails, but rare in others. A TEM foil transecting a garnet domain with concentrated lattice rotation in association with inclusions reveals well developed polygonal subgrain walls with few free dislocations. Where dislocation density is greatest, almost no Journal of Structural Geology 30: 777-790

  3. Effects of chemical composition and mixing state on size-resolved hygroscopicity and cloud condensation nuclei activity of submicron aerosols at a suburban site in northern Japan in summer

    Science.gov (United States)

    Müller, Astrid; Miyazaki, Yuzo; Aggarwal, Shankar G.; Kitamori, Yasuyuki; Boreddy, Suresh K. R.; Kawamura, Kimitaka

    2017-09-01

    Ambient hygroscopic properties, numbers of size-segregated cloud condensation nuclei (CCN) at different supersaturations (0.1%-0.8%), and the chemical composition of submicron particles were simultaneously measured at a suburban site in northern Japan in summer. Two distinct periods with different growth factors (GF), CCN activation diameters, and chemical compositions were observed. The data suggest that internally mixed sulfate aerosols dominated the accumulation size mode in relatively aged aerosols during the first period, whereas particles observed during the latter periods showed external mixing dominated by organics, which was linked to low hygroscopicity and CCN activity. In particular, the higher loading of water-soluble organic matter (WSOM; 60% of OM by mass) with increased WSOM/sulfate ratios corresponded to a low hygroscopicity parameter derived from the CCN measurement (κCCN = 0.15 ± 0.02) at a dry diameter (Ddry) of 146 nm. The results suggest that WSOM, likely dominated by the influence of biogenic sources, contributed to reducing the hygroscopicity and CCN activation at this particle size. Temporal variations in the number concentrations for low GF mode at Ddry = 49.6 nm were similar to those in the elemental carbon (EC) concentration, suggesting that EC contributed to reducing hygroscopicity at this smaller size. Our results suggest that chemical composition and mixing state are important factors controlling the hygroscopicity and CCN activation of submicron particles. These results provide useful data sets of size-resolved subsaturated and supersaturated hygroscopicity and highlight the importance of the abundance of OM relative to sulfate in predicting the effects on climate change.

  4. Particle incorporation in metallic melts during dendritic solidification-undercooling experiments under reduced gravity

    Energy Technology Data Exchange (ETDEWEB)

    Lierfeld, T. [Institute of Space Simulation, German Aerospace Center (DLR), D-51170 Cologne (Germany); Institute of Materials, Ruhr-University Bochum, D-44780 Bochum (Germany)], E-Mail: thomas.lierfeld@dlr.de; Gandham, P. [Institute of Space Simulation, German Aerospace Center (DLR), D-51170 Cologne (Germany); Department of Metallurgical and Materials Engineering, IITM, Chennai (India); Kolbe, M. [Institute of Space Simulation, German Aerospace Center (DLR), D-51170 Cologne (Germany); Schenk, T. [Experiments Division (ID19), ESRF, F-38043 Grenoble (France); Laboratoire de Physique des Materiaux, EdM de Nancy, F-54042 Nancy (France); Singer, H.M. [Laboratory for Solid State Physics, Swiss Federal Institute of Technology ETH, CH-8093 Zurich (Switzerland); Eggeler, G. [Institute of Materials, Ruhr-University Bochum, D-44780 Bochum (Germany); Herlach, D.M. [Institute of Space Simulation, German Aerospace Center (DLR), D-51170 Cologne (Germany)

    2007-03-25

    The interaction of ceramic particles with a dendritic solid/liquid-interface has been investigated by undercooling experiments with different levels of convection: (i) in a terrestrial electromagnetic levitation facility and (ii) in TEMPUS, a facility for containerless processing, under low gravity conditions during parabolic flights. Entrapment of particles in ground experiments and engulfment of a significant fraction of submicron particles under low gravity conditions are attributed to the lower level of convection in the latter experiments and to morphological features of dendritic solidification. X-ray radiography has been used for in situ observations of directional solidification in Al{sub 90}Cu{sub 10} with alumina particles.

  5. Particle Transport in Parallel-Plate Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Rader, D.J.; Geller, A.S.

    1999-08-01

    A major cause of semiconductor yield degradation is contaminant particles that deposit on wafers while they reside in processing tools during integrated circuit manufacturing. This report presents numerical models for assessing particle transport and deposition in a parallel-plate geometry characteristic of a wide range of single-wafer processing tools: uniform downward flow exiting a perforated-plate showerhead separated by a gap from a circular wafer resting on a parallel susceptor. Particles are assumed to originate either upstream of the showerhead or from a specified position between the plates. The physical mechanisms controlling particle deposition and transport (inertia, diffusion, fluid drag, and external forces) are reviewed, with an emphasis on conditions encountered in semiconductor process tools (i.e., sub-atmospheric pressures and submicron particles). Isothermal flow is assumed, although small temperature differences are allowed to drive particle thermophoresis. Numerical solutions of the flow field are presented which agree with an analytic, creeping-flow expression for Re < 4. Deposition is quantified by use of a particle collection efficiency, which is defined as the fraction of particles in the reactor that deposit on the wafer. Analytic expressions for collection efficiency are presented for the limiting case where external forces control deposition (i.e., neglecting particle diffusion and inertia). Deposition from simultaneous particle diffusion and external forces is analyzed by an Eulerian formulation; for creeping flow and particles released from a planar trap, the analysis yields an analytic, integral expression for particle deposition based on process and particle properties. Deposition from simultaneous particle inertia and external forces is analyzed by a Lagrangian formulation, which can describe inertia-enhanced deposition resulting from particle acceleration in the showerhead. An approximate analytic expression is derived for particle

  6. Lipid exchange by ultracentrifugation

    DEFF Research Database (Denmark)

    Drachmann, Nikolaj Düring; Olesen, Claus

    2014-01-01

    Lipids play an important role in maintaining P-type ATPase structure and function, and often they are crucial for ATPase activity. When the P-type ATPases are in the membrane, they are surrounded by a mix of different lipids species with varying aliphatic chain lengths and saturation......, and the complex interplay between the lipids and the P-type ATPases are still not well understood. We here describe a robust method to exchange the majority of the lipids surrounding the ATPase after solubilisation and/or purification with a target lipid of interest. The method is based on an ultracentrifugation...... step, where the protein sample is spun through a dense buffer containing large excess of the target lipid, which results in an approximately 80-85 % lipid exchange. The method is a very gently technique that maintains protein folding during the process, hence allowing further characterization...

  7. Nutrients and neurodevelopment: lipids.

    Science.gov (United States)

    González, Horacio F; Visentin, Silvana

    2016-10-01

    Nutrients, lipids in particular, make up the central nervous system structure and play major functional roles: they stimulate development, migration, and nerve cell differentiation. They are part of gray matter, white matter, nerve nuclei, and synaptogenesis. Breast milk contains lipids which are crucial for infant brain development. The lipid profile of breast milk was used as a guideline for the development of breast milk substitutes. However, to date, no substitute has matched it. Complementary feeding should include docosahexaenoic acid, arachidonic acid, other polyunsaturated fatty acids, saturated fatty acids, and complex lipids found in milk fat. The lipid composition of breast milk depends on maternal intake and nutritional status during pregnancy and breast-feeding. It has a great impact on development. Our goal is to review scientific literature regarding the role of lipids on infant brain development and the importance of breast milk lipid composition, maternal diet, and complementary feeding.

  8. Lipid Structure in Triolein Lipid Droplets

    DEFF Research Database (Denmark)

    Chaban, Vitaly V; Khandelia, Himanshu

    2014-01-01

    Lipid droplets (LDs) are primary repositories of esterified fatty acids and sterols in animal cells. These organelles originate on the lumenal or cytoplasmic side of endoplasmic reticulum (ER) membrane and are released to the cytosol. In contrast to other intracellular organelles, LDs are composed...... of a mass of hydrophobic lipid esters coved by phospholipid monolayer. The small size and unique architecture of LDs makes it complicated to study LD structure by modern experimental methods. We discuss coarse-grained molecular dynamics (MD) simulations of LD formation in systems containing 1-palmitoyl-2...... to coarse-grained simulations, the presence of PE lipids at the interface has a little impact on distribution of components and on the overall LD structure. (4) The thickness of the lipid monolayer at the surface of the droplet is similar to the thickness of one leaflet of a bilayer. Computer simulations...

  9. Fluorescent-magnetic Janus particles prepared via seed emulsion polymerization.

    Science.gov (United States)

    Kaewsaneha, Chariya; Bitar, Ahmad; Tangboriboonrat, Pramuan; Polpanich, Duangporn; Elaissari, Abdelhamid

    2014-06-15

    Anisotropic polymeric colloidal or Janus particles possessing simultaneous magnetic and fluorescent properties were successfully prepared via the swelling-diffusion or the in situ emulsion polymerization method. In the swelling-diffusion process, magnetic emulsions (an organic ferrofluid dispersed in aqueous medium) were synthesized and used for seeds of submicron magnetic Janus particles. After swelling the anisotropic particles obtained by 1-pyrene-carboxaldehyde fluorescent dye dissolved in tetrahydrofuran, well-defined fluorescent-magnetic Janus particles were produced. In the in situ emulsion polymerization, styrene monomer mixed with fluorescent dye monomers, i.e., 1-pyrenylmethyl methacrylate (PyMMA) or fluorescein dimethacrylate (FDMA), and an oil-soluble initiator (2,2'-azobis(2-isobutyronitrile)) were emulsified in the presence of magnetic seed emulsions. The confocal microscopic images showed the fluorescent-magnetic Janus particles with high fluorescent intensity when a fluorescent crosslinker monomer FDMA was employed.

  10. Submicron InP DHBT technology for high-speed high-swing mixed-signal ICs

    DEFF Research Database (Denmark)

    Godin, Jean; Nodjiadjim, V.; Riet, Muriel;

    2008-01-01

    We report on the development of a submicron InP DHBT technology, optimized for the fabrication of 50-GHz-clock mixed signal ICs. In-depth study of device geometry and structure has allowed to get the needed performances and yield. Special attention has been paid to critical thermal behavior. Vari...

  11. Do nanofill or submicron composites show improved smoothness and gloss? A systematic review of in vitro studies

    NARCIS (Netherlands)

    Kaizer, M.R.; Oliveira-Ogliari, A. de; Cenci, M.S.; Opdam, N.J.M.; Moraes, R.R.

    2014-01-01

    OBJECTIVES: Despite nanofill and submicron composites' aim to provide high initial polishing combined with superior smoothness and gloss retention, the question still remains whether clinicians should consider using these new materials over traditional microhybrids. The aim of this paper was to syst

  12. Hemodynamics and the parameters of the heart mass in the dog after inhalation of submicron /sup 239/Pu dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Kalmykova, Z.I.; Buldakov, Z.I.; Kharunzhin, V.V.

    The growth of the right heart mass was mainly registered in dogs after inhalation of different quantities of /sup 239/Pu submicron dioxide. This was correlated with the value of /sup 239/Pu deposited in the lungs and associated with the systemic hemodynamic disorders.

  13. A Nordic project on high speed low power design in sub-micron CMOS technology for mobile phones

    DEFF Research Database (Denmark)

    Olesen, Ole

    This paper is a survey paper presenting the Nordic CONFRONT project and reporting some results from the group at CIE/DTU, Denmark. The objective of the project is to demonstrate the feasibility of sub-micron CMOS for the realisation of RF front-end circuits operating at frequencies in the 1...

  14. A Novel Leakage-tolerant Domino Logic Circuit With Feedback From Footer Transistor In Ultra Deep Submicron CMOS

    DEFF Research Database (Denmark)

    Moradi, Farshad; Peiravi, Ali; Mahmoodi, Hamid

    As the CMOS manufacturing process scales down into the ultra deep sub-micron regime, the leakage current becomes an increasingly more important consideration in VLSI circuit design. In this paper, a high speed and noise immune domino logic circuit is presented which uses the property of the footer...

  15. A Nordic project on high speed low power design in sub-micron CMOS technology for mobile phones

    DEFF Research Database (Denmark)

    Olesen, Ole

    This paper is a survey paper presenting the Nordic CONFRONT project and reporting some results from the group at CIE/DTU, Denmark. The objective of the project is to demonstrate the feasibility of sub-micron CMOS for the realisation of RF front-end circuits operating at frequencies in the 1.8-2.0...

  16. Visualization and quantification of four steps in magnetic field induced two-dimensional ordering of superparamagnetic submicron particles

    DEFF Research Database (Denmark)

    Gajula, Gnana Prakash; Neves Petersen, Teresa; Petersen, Steffen B.

    2010-01-01

    We hereby report a methodology that permits a quantitative investigation of the temporal self-organization of superparamagnetic nanoparticles in the presence of an external magnetic field. The kinetics of field-induced self-organization into linear chains, time-dependent chain-size distribution...

  17. Fabrication of high-quality submicron Nb/Al-AlOx/Nb tunnel junctions

    Institute of Scientific and Technical Information of China (English)

    Yu Hai-Feng; Cao Wen-Hui; Zhu Xiao-Bo; Yang Hai-Fang; Yu Hong-Wei; Ren Yu-Feng; Gu Chang-Zhi; Chen Geng-Hua; Zhao Shi-Ping

    2008-01-01

    Nb/Al-AlOx/Nb tunnel junctions are often used in the studies of macroscopic quantum phenomena and supercon-ducting qubit applications of the Josepheon devices. In this work, we describe a convenient and reliable process using electron beam lithography for the fabrication of high-quality, submicron-sized Nb/Al-AlOx/Nb Josephson junctions.The technique follows the well-known selective Nb etching process and produces high-quality junctions with Vm=100 mV at 2.3 K for the typical critical current density of 2.2 kA/cm2, which can be adjusted by controlling the oxygen pressure and oxidation time during the formation of the tunnelling barrier. We present the results of the temperature depen-dence of the sub-gap current and in-plane magnetic-field dependence of the critical current, and compare them with the theoretical predictions.

  18. Occurrence of weak, sub-micron, tropospheric aerosol events at high Arctic latitudes

    Science.gov (United States)

    O'Neill, N. T.; Pancrati, O.; Baibakov, K.; Eloranta, E.; Batchelor, R. L.; Freemantle, J.; McArthur, L. J. B.; Strong, K.; Lindenmaier, R.

    2008-07-01

    Numerous fine mode (sub-micron) aerosol optical events were observed during the summer of 2007 at the High Arctic atmospheric observatory (PEARL) located at Eureka, Nunavut, Canada. Half of these events could be traced to forest fires in southern and eastern Russia and the Northwest Territories of Canada. The most notable findings were that (a) a combination of ground-based measurements (passive sunphotometry, high spectral resolution lidar) could be employed to determine that weak (near sub-visual) fine mode events had occurred, and (b) this data combined with remote sensing imagery products (MODIS, OMI-AI, FLAMBE fire sources), Fourier transform spectroscopy and back trajectories could be employed to identify the smoke events.

  19. Experimental studies of the noise properties of a deep submicron CMOS process

    Energy Technology Data Exchange (ETDEWEB)

    Manghisoni, M.; Re, V. E-mail: valere@unibg.it; Speziali, V.; Svelto, F

    2001-04-01

    Deep submicron CMOS technologies are presently very attractive for front-end electronics design, because of their features in terms of low power consumption, high integration density and radiation tolerance. A full understanding of the noise parameters of the devices belonging to these technologies is needed to confirm that they can be used to implement low-noise analog blocks. This paper describes a noise test system, which was purposely developed to measure the noise voltage spectrum of CMOS devices in a frequency range extending up to 100 MHz. As an application example, the results of the experimental characterization of the noise properties of a 0.35 {mu}m CMOS process are presented.

  20. Low-loss, submicron chalcogenide integrated photonics with chlorine plasma etching

    Energy Technology Data Exchange (ETDEWEB)

    Chiles, Jeff; Malinowski, Marcin; Rao, Ashutosh [CREOL, The College of Optics and Photonics, University of Central Florida, Orlando, Florida 32816 (United States); Novak, Spencer; Richardson, Kathleen [CREOL, The College of Optics and Photonics, University of Central Florida, Orlando, Florida 32816 (United States); Department of Materials Science and Engineering, COMSET, Clemson University, Clemson, South Carolina 29634 (United States); Fathpour, Sasan, E-mail: fathpour@creol.ucf.edu [CREOL, The College of Optics and Photonics, University of Central Florida, Orlando, Florida 32816 (United States); Department of Electrical Engineering and Computer Science, University of Central Florida, Orlando, Florida 32816 (United States)

    2015-03-16

    A chlorine plasma etching-based method for the fabrication of high-performance chalcogenide-based integrated photonics on silicon substrates is presented. By optimizing the etching conditions, chlorine plasma is employed to produce extremely low-roughness etched sidewalls on waveguides with minimal penalty to propagation loss. Using this fabrication method, microring resonators with reco