A diagram of the optical setup is shown in Fig. 4. Two illumination options were used, a 100 W mercury arc lamp (Zeiss) and a 10 mW HeNe laser (632.8 nm). Both light sources were coupled into the back port of a Zeiss Axiovert 200 ﬂuorescence microscope via an optical switch (ﬂipper mirror and mechanical housing), which allowed selection of one of the two light sources. An optical scrambler (Technical Video Inc., USA) was used to expand the laser beam. The optical scrambler consists of a lens for coupling the laser into a high-numerical aperture-optical ﬁbre, the output light from the ﬁbre then being passed through a two- lens beam expander. The excitation light was imaged onto the chip using a 20 objective lens (0.75 NA, Zeiss Fluar) giving an illumination area of approximately 50 mm in diameter. Fluorescence emission from the beads was collected using the same objective lens. Emitted light was ﬁltered using either a Cy5 (when using the laser or mercury lamp) or FITC (when using the mercury lamp) ﬁlter set (Glen Spectra Ltd., UK). The emitted light was spatially ﬁltered to reduce the noise using a 50 mm diameter pinhole positioned at the primary focal plane of the microscope camera port, giving a ﬁnal detection region of approxi- mately 3 mm diameter. Fluorescence was collected and quantiﬁed using a photomultiplier (H7710-03, Hamamat- su), with power supply (C7169, Hamamatsu) and ampliﬁer (C7319, Hamamatsu) fed into a DAQ (NI6040E, National Instruments). Particles moving through the channel were simultaneously imaged using a high-sensitivity digital camera (Orca ER, Hamamatsu) attached to a second port
in scale and these smaller particles are usually fabricated without simple mixing and without heating and so are amorphous and non-crystalline; they are usually made from non-apatite calcium phosphate. This amorphous material can have potential some applications such as in enamel remineralisation, but less so in tissue engineering, which requires structural strength and so was considered outside the focus of this work. The larger multiple-micron sized particles were also not considered since reports elsewhere suggest that these larger particles are similarly structurally weak and can take time to grow, and so can be more difficult to control. Wide-spread reporting elsewhere of apatite particles at the micron-scale suggests that this scale of particle is of greater interest and use .
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Commercial polystyrene spheres were used to assess particle uptake by the cells since this enabled studies of homogenous particles of known size and number. These particles have been used to study particle translocation across a barrier 35 and to determine the phagocytic ability of numerous cell types. 36 In the case of micron-sized (1 mm) particles, the internalization was different between the two types of cells. The dural epithelial cells exposed to micron sized particles for 24 h, internalized either no particles or a very small number ( < 5 particles per cell). Dural ﬁbroblasts internalized 11 to 20 micron particles or more than 20 par- ticles in 24 h. There were some nanoparticles outside the cells but they were not count in the results. Differences between the capacity of different cell lines to internalise polystyrene microspheres and micron-size silica particles have been widely documented. 37,38 Confocal and deconvolu- tion microscopy, an established method for detection of par- ticle internalization, 39 conﬁrmed the difference between dural ﬁbroblasts and epithelial cell capacity to take up micron sized particles.
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nanoparticles influence the crack branching more effectively than micron sized particles. In a study by Saidina et al  with calcium copper titanate and barium titanate reinforced epoxy composites, the reported tensile strength is about 40 MPa and 55 MPa respectively at 5 vol% loading, which is very low compared to the tensile strength of 40-47 MPa achieved in the case of Epoxy-TiB 2 nanocomposites with only 0.2-0.4 vol% addition of TiB 2 . In an another study by Luyt et al  using copper powder
The bondwire is plunged into a bottle containing micrometre-sized particle powder (with known particle diameter) so that some particles adhere on to it due to the attractive interparticle forces that exist in micron and sub-micron sized particles . With the aid of the linear translation stage, this bondwire (containing the adherent particles) is then gently rubbed onto the sensor surface, allowing the particles to fall on to the sensor surface. The deposition of this particle mass onto the sensor surface produces a shift in frequency at the SAWR oscillator output. The entire deposition process was visually monitored in real time through a digital microscope, to guide the placement of particulate mass on to the sensor surface. In addition, a photomicrograph of the sensor surface with the deposited particles was also captured, which was used to count the number of particles deposited onto the sensing area. Figure 6[B] shows the photograph of gold particles with diameter of < 1 µm deposited on the sensing area of the SAWR particle sensor. The scanning electron microscopic images of these gold particles are shown in Figure 6[C]. The sensor unit is placed inside an environmental chamber to ensure ambient temperature stability, to avoid both air current effects and the deposition of any foreign material on the sensor within the laboratory environment.
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Figure 3 shows typical recorded video images of a DEP experiment before and after applying the electric field. Both images are approximately half-length frame size (540 × 360 pixels) and have been cropped and juxtaposed for illustrative purposes. Figure 3(a) shows the planar interdigitated array before application of the electric potential where particles exhibit Brownian motion in the suspending medium. This corresponds to figure 2(a)(i). Figure 3(b) shows particle collection in the immediate vicinity of the electrodes under the action of positive DEP about five seconds after applying the field. The particle concentration in the plane immediately above the electrodes is depleted—as depicted in figure 2(a)(ii). The time-dependent particle concentration on the electrodes is determined by experimental conditions, in particular the polarizability which is a function of frequency. Consequently, an accurate measurement of bead concentration as a function of time should enable a quantification of the frequency-dependent DEP force.
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In the inverse micro emulsion route, the reactants are allowed to combine in micrometer or sub- micrometer size drops of aqueous phase, which are dispersed in a large volume of organic phase . The aqueous droplets are stabilized by surfactant molecules, which are oriented in the form of reverse micelles. As the growth of the reaction product is limited by the size of the aqueous droplets in these nanoreactors, the particle size obtained is in sub-micrometer or nanometer scale. In the present synthesis, inter mixing of the reactants took place within the aqueous droplets. Slow evaporation of the emulsion resulted in the formation of a gel consisting of acetates of Mn and Li in narrow regions, which were surrounded by surfactant molecules. During the subsequent heat treatment, the mixed metal acetates as well as the surfactant were oxidized resulting in the formation of sub-micron size particles of LiMn 2 O 4 .
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3.1 Introduction ............................................................................................ 3-1 3.2 The benefits of mobility measurements of charged droplets..................... 3-2 3.3 Instrumentation ....................................................................................... 3-3 3.3.1 Electrospray ionization source ..................................................... 3-5 3.3.2 Ion mobility cell and the ping-pong technique ............................. 3-5 3.3.3 Phase Doppler anemometer ......................................................... 3-6 3.4 Equations of motion within an ion mobility cell ...................................... 3-9 3.5 Modeling droplet behavior to determine droplet relaxation time .............. 3-11 3.5.1 Modeling the droplet motion using Euler’s Method ..................... 3-11 3.5.2 Model results as a function of droplet size ................................... 3-13 3.5.3 Model results as a function of droplet charge ............................... 3-15 3.6 Evaporation of micron-sized droplets within the IMS .............................. 3-17 3.7 Conclusions ............................................................................................ 3-20 3.8 References .............................................................................................. 3-21
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materials exhibit excellent antibacterial characteristics even at the lower concentrations and are nontoxic. Organic materials based antibacterial agents are chemically unstable and cannot be utilized under precise conditions. But it was effectively tackled by the silver embedded silica particles due to its high anti antibacterial and chemical durability. In general, the oxidation of alcohols had been catalyzed by chromium. Due to its high cost and harmful nature, it was greatly avoided for utilization. The silver–silica composite catalyst induces the high conversion rate of the alcohols oxidation due to its highly exposed surface, which is responsible for more reaction sites . The presence of silver clusters in silica promotes the third-order optical non- linear susceptibility, which leads to an intensity-dependent refractive index thus allowing the scheduling and the development of all-optical switching devices. The well- adsorbed silver nanoparticles inside the channel of silica completely reduce the catalyst leaking. It makes the catalyst stable and anti-contaminated, which lead to a promoted sensor for the determination of hydrogen peroxide . The tunable pore sizes with narrow distributions and well- defined surface properties of the composite allowing them to adsorb certain kinds of drugs and release these drugs in a more reproducible manner and find their application in drug delivery . Besides the present results suggest that the fused silica could generate different photoluminescence emission, excited with different incident beams, which can be interesting for applications in the optoelectronic field.
In this study sterile clinically-relevant nanometre-sized UHMWPE wear particles which had a size range of <50 nm, were successfully generated and isolated. The results showed for the ﬁrst time that nanometre-sized UHMWPE wear particles with a size range of <50 nm did not stimulate proinﬂammatory cytokine release including TNF- a , IL-1b, IL-6 and IL-8, from human periph- eral blood mononuclear cells (PBMNCs). This conclusion has answered long-term clinical concerns about the biological response to the large number of nanometre-sized UHMWPE wear particles which are generated from highly crosslinked UHMWPE acetabular cups in total hip replacements. In addition, this study indicated that size, composition and morphology of particles played an important role in the particle-induced osteolysis process. Further investigation to determine the cellular uptake mechanism of clinically-relevant nanometre-sized UHMWPE wear particles compared to micrometre-sized UHMWPE wear particles is under- way with the aim of revealing the relationship between the cellular uptake mechanism and cellular response to different sizes of UHMWPE wear particles.
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In previous research on SIRENS, both time-integrated and time-resolved measurements have been used to find the temperature and density of a variety of metallic and non-metallic plasmas . A similar study was also performed on the electrothermal plasma device PIPE . These, and other studies performed with the electrothermal devices, used the passive radiation technique of optical (or atomic) emission spectroscopy (OES). This method relies on radiation emitted by the plasma, or particles within the plasma. Other general methods include intrusive techniques and active radiation techniques. The Langmuir, or electrostatic, probe is an example of an intrusive technique. As previously described, this technique was attempted as a way to verify OES measurements, but was unsuitable in this study. Active radiation techniques rely on an external source of radiation as a probe of the plasma so that transmission, absorption, scattering, or reflection measurements can be made. The specialized equipment required made these techniques unsuitable as well .
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Although we cannot yet pinpoint the speciﬁc mechanism leading to entrainment, the structure of the near-ﬁeld ﬂow is likely to play a crucial role. The entrainment we observe requires almost head-on collisions, which is likely to be facilitated by the type of stagnation point found (on average) in front of the cell 37,38 . After reaching the cell apex, the entrained particles slide down the sides of the cell body along a high-shear region almost co-moving with the microorganism, and are eventually left behind having spent slightly more than half of the jump in the front part of the cell (54 ± 9%). The no-slip boundary on the bodies of microorganisms, and the stagnation points in their ﬂow ﬁelds, have in fact been argued to play a major role in large microparticle displacements 5,21,29 , which are seen here to dominate the effective diffusivity. Our results support these conjectures.
Different aspects of particle segregation in fluidized beds have been widely investigated experimentally and numerically during the past several decades covering segregation mechanisms, possible incompatibilities and patterns, feasibility analysis, applications, and other associated specifications . The common numerical methods are based on Eulerian-Lagrangian (discrete element model, DEM) and Eulerian-Eulerian (multi-fluid model, MFM) models via computational fluid dynamics (CFD) simulations . The Eulerian–Lagrangian approach has the advantage of accounting for the corpuscular nature of particles by explicitly evaluating their trajectories. The disadvantage, however,
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Fabrication of sub-micron (meso)pores in single crystal diamond membranes, which span the entirety of the membrane, is described for the first time, and the translocation properties of polymeric particles through the pore investigated. The pores are produced using a combination of laser micromachining to form the membrane and electron beam induced etching to form the pore. Single crystal diamond as the membrane material, has the advantages of chemical stability and durability, does not hydrate and swell, has outstanding electrical properties that facilitate fast, low noise current-time measurements and is optically transparent for combined optical-conductance sensing. The resulting pores are characterized individually using both conductance measurements, employing a microcapillary electrochemical setup, and electron microscopy. Proof-of-concept experiments to sense charged polystyrene particles as they are electrophoretically driven through a single diamond pore are performed, and the impact of this new pore material on particle translocation is explored. These findings reveal the potential of diamond as a platform for pore-based sensing technologies and pave the way for the fabrication of single nanopores which span the entirety of a diamond membrane.
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Micro/nanobubbles (MNBs) are spherical vesicles consisting of a shell and core, and they have been used as ultrasound contrast agents for several decades in the field of medicine [10, 17-20]. The term microbubble is commonly used in reference to ultrasound contrast agents owing to their micrometer size [21, 22]. Microbubble-based contrast agents have also been used for a photoacoustic imaging technique, which is a non-invasive real-time molecular imaging technique based on optical absorption of tissues [23-25]. Nanobubbles have been investigated for diagnostic and therapeutic purposes owing to their nanometer size, for enhancing cellular penetration of these bubbles [22, 26- 31]. Tumors exhibit leaky vasculature and various researchers have investigated the effect of enhanced permeability and retention (EPR) effect, which is the ability of tumors to accumulate particles in the size range of 380–780 nm. Yin et al. demonstrated that nanobubbles exhibited similar echogenic properties as microbubbles when high frequencies of ultrasound were used and nanobubbles were retained in tumors for longer periods as compared to microbubbles . Various other researchers have also investigated nanobubbles as ultrasound contrast agents for tumor imaging and drug/gene delivery applications [2, 31, 33-35]. Compared to nanosized liposomes, which contain lipid bilayer membrane and hydrophilic aqueous core, nanobubbles have monolayer shells encapsulating a hydrophobic gas core, making them feasible for gas delivery applications [20, 26, 36, 37]. Both microsized and nanosized bubbles have been used for oxygen delivery . Therefore, in this review, the term micro/nanobubbles (MNBs) was used to address the similarity of the properties of these vesicles in relation to the oxygen supply and their applications. A higher surface contact area, smaller size, polydisperse size distribution, higher payload, higher cellular uptake, and an efficient gas delivery mechanism are promising aspects of MNBs, and these attributes make MNBs suitable for gas and drug delivery applications [12, 38-43].
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Aluminium-based metal matrix composites (MMCs) reinforced with ceramic particles is interesting structural and functional materials. They have been found in a wide range of applications in automotive and aerospace industries because of their lightweight, high stiffness and strength, high thermal stability and their superior wear resistance, compared to the unreinforced aluminium alloys [4, 5].
All NHA powders were characterized by X-ray diffraction (XRD) using Cu-Ka radiation (Siemens D500 Kristalloflex; Bruker AXS Inc.), scanning electron microscopy (SEM) (JEOL JSM-35CF), and inductively coupled plasma–atomic emission spectroscopy conducted by Impact Analytical (Midland, MI, USA) to determine its Ca/P ratio. A BET surface area analyzer (SA3100; Beckman Coulter) was used to measure the surface area of the particles, and the equiva- lent spherical crystallite size was then determined using a theoretical HA density of 3.16 g/cm 3 . Transmission electron
interfacial tensions correspond to larger ﬂ uctuation amplitudes and, hence, higher signal-to-noise ratios. Furthermore, in spinning droplet tensiometry the density ratio between the dispersed and the continuous phases has to be lower than unity, whereas our micro ﬂ uidic approach can measure the interfacial properties of droplets either lighter or heavier than the surrounding medium. Finally, the time required for the droplet shape to equilibrate during spinning droplet measurements can be quite long (up to 1 h) due to the slow droplet dynamics in the ULIFT regime. Conversely, micron-sized droplets, enclosed in a temperature-controlled micro ﬂ uidic environment, rapidly reach the thermal equilibrium, and data acquisition for thermal capillary wave analysis is hence very fast (i.e., a few minutes).
Since negligible electric fields exists within airspaces of the respiratory system, which will act as a faraday cage. The first consideration does not apply. The second factor may be important for dense aerosols. When charged particles are close to the walls of the airways. In general, particles with high electric mobility can have an enhanced respiratory tract deposition even though no external field is applied across the chest. The electrostatic enhancement of particle deposition, when it does occur, takes place predominantly in the human trachea. In particle, most ambient aerosols have reached charge equilibrium and have relatively low charge levels. Thus the deposition due to charge is usually small compared to deposition by the mechanical mechanisms. Micro particles deposition in large airways (example naral, oral and upper tracheobronchial airways) during inhalation results mainly from impaction, secondary flow convection and turbulent dispersion. However, enhanced deposition can be observed mostly around the glottis and the sidewalls of the upper trachea due to inertial impaction arising from the laryngeal jet and secondary flows (Xi and Longest 2007,and Zhang et al2005).
The need for high-performance and lightweight materials in automobile and aerospace industries has led to extensive research and development efforts generating metal matrix composites (MMCs) and cost-effective fabrication technologies. The major disadvantage of MMCs usually lies in the relatively high cost of fabrication and reinforcement materials. The cost-effective processing of composite materials is, therefore, an essential element for expanding their applications. This is especially true for the high performance magnesium-based materials due to their high material and processing costs [1-4]. Since hybrid composites are fabricated by adding two or more reinforcements into matrix materials, excellent properties and a high degree of design freedom combinations including short fibres and different size particles become achievable. As magnesium matrix composites are reinforced with hybrid reinforcement in which both of the particles and short fibres are employed, large opportunities are provided to optimize the engineering performance of magnesium based composites for potential applications in automobile and aerospace industries . The fabrication process for the hybrid preform with cellular structure made by micron-sized ceramic Al 2 O 3 particles and Al 2 O 3 fibres was described
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