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Droplets
Kinds of Droplets Terms modified by Droplets Selected AbstractsA nonlinear atomization model for computation of drop size distributions and spray simulationsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 11 2005Hongbok Park Abstract A model has been developed to provide a comprehensive simulation of a spray formed by a high-speed liquid jet. The primary atomization process is simulated in a completely nonlinear fashion using the boundary element method under the assumption of axisymmetric, inviscid flow. The presence of the orifice boundary layer is simulated with a ring vortex whose strength and location are uniquely determined from boundary layer properties at the orifice exit plane. Droplet and axisymmetric ligament tracking models have been developed to provide more comprehensive spray simulations. The breakup of the axisymmetric ligaments shed from the parent surface is assessed both in a nonlinear fashion as well as using the linear stability analysis of Ponstein. Using this latter approach, drop size distributions have been generated from first principles and compared with the popular Rosin,Rammler model. Copyright © 2005 John Wiley & Sons, Ltd. [source] Behaviour of a Moving Droplet under Electrowetting Actuation: Numerical SimulationTHE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 1 2006K. Mohseni Abstract Numerical simulation of droplet transport in microchannels under electrostatic actuation is investigated. Volume-of-Fluid (VOF) technique is employed, in which electrowetting effects are implemented through Lippmann's relation in the form of modified contact angles at the boundary. A velocity of about 35 mm/s is achieved with the actuation of 40 V. The droplet flow under electrowetting actuation is characterized for the majority of the process parameters such as actuation voltage, channel dimension, electrode size, and resultant velocity. On étudie la simulation numérique du transport de gouttelettes dans des microcanaux lors d'une actuation électrostatique. On emploie la technique des volumes de fluide (VOF), dans laquelle les effets de l'électromouillage sont introduits dans la relation de Lippmann sous la forme d'angles de contact modifiés à la frontière. Une vitesse d'environ 35 mm/s est atteinte avec une actuation de 40 V. L'écoulement des gouttelettes dans l'actuation électromouillante est caractérisé pour la majorité des paramètres de procédé, tels que le voltage d'actuation, la dimension des canaux, la taille des électrodes et la vitesse résultante. [source] Titelbild: Photomanipulation of a Droplet by the Chromocapillary Effect (Angew. Chem.ANGEWANDTE CHEMIE, Issue 49 200949/2009) Durch Einstrahlung von Licht kann ein wellenlängenabhängiger Gradient der Grenzflächenspannung an einer Flüssig-flüssig-Grenzfläche erzeugt werden, wodurch sich Tröpfchen in entgegengesetzter Richtung des Gradienten in Bewegung versetzen lassen. Diesen "Chromokapillareffekt" beschreiben D. Baigl et,al. in ihrer Zuschrift auf S.,9445,ff. Die Flüssigkeitströpfchen können mit guter Präzision zu beliebigen Formen, z.,B. einem Herz, angeordnet werden. [source] Photomanipulation of a Droplet by the Chromocapillary Effect,ANGEWANDTE CHEMIE, Issue 49 2009Antoine Diguet Herz Ass: Flüssigkeitströpfchen lassen sich entlang Trajektorien mit beliebiger Form bewegen (wie das abgebildete Herz), indem man durch Bestrahlen mit Licht einen wellenlängenabhängigen Gradienten der Grenzflächenspannung an einer Flüssig-flüssig-Grenzfläche erzeugt. Bei diesem neuartigen Phänomen (,Farbkapillareffekt") führt ein Fluss durch die Grenzfläche zu einer Tröpfchenbewegung in Gegenrichtung zum Gradienten. [source] Simulation of two-phase flow with sub-scale droplet and bubble effectsCOMPUTER GRAPHICS FORUM, Issue 2 2009Viorel Mihalef Abstract We present a new Eulerian-Lagrangian method for physics-based simulation of fluid flow, which includes automatic generation of sub-scale spray and bubbles. The Marker Level Set method is used to provide a simple geometric criterion for free marker generation. A filtering method, inspired from Weber number thresholding, further controls the free marker generation (in a physics-based manner). Two separate models are used, one for sub-scale droplets, the other for sub-scale bubbles. Droplets are evolved in a Newtonian manner, using a density-extension drag force field, while bubbles are evolved using a model based on Stokes' Law. We show that our model for sub-scale droplet and bubble dynamics is simple to couple with a full (macro-scale) Navier-Stokes two-phase flow model and is quite powerful in its applications. Our animations include coarse grained multiphase features interacting with fine scale multiphase features. [source] Factors influencing the effectiveness of an attracticide formulation against the Oriental fruit moth, Grapholita molestaENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 2 2004Maya L. Evenden Abstract An attracticide formulation, LastCallÔOFM, was tested against the Oriental fruit moth Grapholita molesta (Busck) (Lepidoptera: Tortricidae) in replicated small plot field trials in apple, Malus domestica (Borkhausen), orchards in South-eastern Pennsylvania, USA. Attracticide treatments were applied using a calibrated hand pump, and treated plots were compared to similar untreated plots. Male moth activity was monitored using virgin female-baited traps, and the potential for reduction in mating activity was assessed using sentinel virgin females. A comparison of application rates showed that 1500 droplets per ha of the attracticide formulation was as effective as 3000 droplets per ha, and both application rates reduced captures in synthetic pheromone-baited traps for prolonged periods. Droplets placed either at high or low positions within the canopy significantly reduced trap capture and mating with sentinel females. In addition, the only sentinel females that mated in the treated plots were located in the untreated portion of the tree canopy. Mate finding behaviour was equally disrupted by formulations with and without insecticide. Therefore, under the test conditions, the mechanism by which the attracticide formulation worked was by disruption of male orientation, and not by the removal of males due to insecticide poisoning. Two field cage experiments tested the impact of population density on the competitiveness of the attracticide formulation compared to virgin females. A significant proportion of males were captured in female-baited traps at the highest female-to-droplet ratio tested. Equal proportions of males were captured in attracticide-baited traps at male moth densities of 10, 20, 40, and 80 males per cage. These results clarify some of the factors influencing the effectiveness and possible mechanisms of an attracticide management tactic against the Oriental fruit moth. [source] Magnetic Liquid Marbles: Manipulation of Liquid Droplets Using Highly Hydrophobic Fe3O4 NanoparticlesADVANCED MATERIALS, Issue 6 2010Yan Zhao Magnetic liquid marbles exhibit a remarkable ability to be opened (see image) and closed reversibly under the action of a magnetic field. Liquid can be either extracted from or added to the opened liquid marble simply with a capillary needle. Two opened liquid marbles can also be coalesced into a larger one. The magnetic liquid marbles can be maneuvered two- and three-dimensionally. [source] Photonic Crystals: Patterned Polymeric Domes with 3D and 2D Embedded Colloidal Crystals using Photocurable Emulsion Droplets (Adv. Mater.ADVANCED MATERIALS, Issue 37 200937/2009) The inside cover shows a scheme for the preparation of photonic dome patterns, SEM images of a dome pattern, and a single dome decorated with 2D colloid array, as fabricated in work reported on p 3771 by Seung-Man Yang and co-workers. The background is an optical microscopy image of patterned photonic domes, which can be used as a near-field microlens array. The greenish color of the domes corresponds to the photonic bandgap. [source] Patterned Polymeric Domes with 3D and 2D Embedded Colloidal Crystals using Photocurable Emulsion DropletsADVANCED MATERIALS, Issue 37 2009Shin-Hyun Kim Hierarchical dome patterns are prepared via a novel single-step patterning process. Photonic domes with isotropic reflection colors are patterned on a prepatterned glass substrate with a hydrophobic moiety using photocurable emulsion droplets of all-equal size, which contain concentrated silica particles. Furthermore, embossed domes are patterned with PS particle-stabilized photocurable emulsion droplets, which can act as a near-field microlens array. [source] Janus Supraparticles by Induced Phase Separation of Nanoparticles in DropletsADVANCED MATERIALS, Issue 19 2009Rhutesh K. Shah Biphasic Janus particles with a precisely tunable internal morphology are fabricated using a novel, versatile, and robust technique. This technique can be used in conjunction with microfluidics to produce monodisperse particles, or can be combined with bulk emulsification techniques to produce large quantities of particles. [source] Centerline Placement and Alignment of Anisotropic Nanotubes in High Aspect Ratio Cylindrical Droplets of Nanometer DiameterADVANCED MATERIALS, Issue 1 2009Richa Sharma High aspect ratio cylindrical droplets of carbon-nanotube solutions present interesting hydrodynamic flow patterns during evaporation, where particles are aligned and positioned. The flow inside droplets with diameters <1000,nm positions all the nanotubes along the droplet centerline with 95% precision, while droplets with diameters >3µm align the nanotubes along the droplet edges during evaporation. [source] Synthesis of Light-Diffracting Assemblies from Microspheres and Nanoparticles in Droplets on a Superhydrophobic Surface,ADVANCED MATERIALS, Issue 22 2008Vinayak Rastogi Aqueous suspension droplets of monodisperse latex or latex and gold nanoparticles mixtures assume spherical shape on superhydrophobic substrates. The drying sessile droplets serve as macroscopic templates for assembling microspheres into closed-packed structures. Upon illumination, the supraparticles display discrete colored rings because of the periodic arrangement of latex particles in the surface layer. The physical origin of the colored patterns is explained in detail. [source] Complex Droplets on Chemically Modified Silicon Nanograss,ADVANCED MATERIALS, Issue 18 2008Ville Jokinen Dropping in. Chemically modified silicon nanograss combines nanoscale topography with lithographically defined chemical patterns. The material exhibits a high wettability gradient that allows tailoring of complex droplet shapes. The oxidized nanograss is completely wetting, while the polymer-coated nanograss has a contact angle of ca. 170° and is ultrahydrophobic. Novel droplet behavior on these surfaces is studied experimentally. [source] Formation of Arrayed Droplets by Soft Lithography and Two-Phase Fluid Flow, and Application in Protein Crystallization,ADVANCED MATERIALS, Issue 15 2004B. Zheng Abstract This paper presents an overview of our recent work on the use of soft lithography and two-phase fluid flow to form arrays of droplets. The crucial issues in the formation of stable arrays of droplets and alternating droplets of two sets of aqueous solutions include the geometry of the microchannels, the capillary number, and the water fraction of the system. Glass capillaries could be coupled to the PDMS microchannels and droplets could be transferred into glass capillaries for long-term storage. The arrays of droplets have been applied to screen the conditions for protein crystallization with microbatch and vapor diffusion techniques. [source] Size distributions and stability of toluene diluted heavy oil emulsionsAICHE JOURNAL, Issue 3 2006Chandra W. Angle Abstract The sizes and stability of oil droplets created from various concentrations of heavy oil-in-toluene at a fixed oil:water ratio were investigated during turbulent flow in model process water. The Reynolds number (Re) ranged from 17,000 to 34,500 and was obtained by stirred tank mixing with a Rushton turbine. The droplet sizes were monitored using laser light scattering. Results showed that at high Re and low oil concentrations (that is, low drop-surface coverage), breakage of the droplets was the dominant process, but as Re was reduced, coalescence was dominant. Droplets were less prone to breakage as the oil concentrations in toluene increased, and droplet sizes approached a steady state quickly during mixing. Their size distributions broadened and stability increased as heavy oil in toluene increased. Stability was attributed to a surface coverage by asphaltenes and the consequent interfacial elasticity that provided resilience to breakage. Equilibrium interfacial tension ,E was determined by fitting a diffusion-limited kinetic mathematical model to the data. The Gibbs adsorption model gave a monolayer surface coverage of 3 nm2/mol asphaltenes, consistent with other published results. High zeta potential of the droplets also hindered coalescence. © 2005 American Institute of Chemical Engineers AIChE J, 2006 [source] Stable Free Radical Polymerization in Emulsion: Modeling the Thermodynamics of Monomer Transfer between Droplets and ParticlesMACROMOLECULAR THEORY AND SIMULATIONS, Issue 2-3 2008Jordan Pohn Abstract A mathematical model is developed from polymer solution thermodynamics and stable free radical polymerization kinetics to predict the monomer swelling behavior of large droplets and small particles that coexist during the seeded polymerization of styrene in emulsion. This model is used to predict the sensitivity of polymerized latex stability (based on the persistence of large particles) to changes in seed particle size and final latex target molecular weight. Simulation results show that the use of small seed particles (diameter,,,50 nm) in recipe formulation will lead to polymerization occurring preferentially in the large droplets, and offers theoretical evidence that TEMPO-mediated ab initio emulsion polymerizations will not be feasible. Our predictions are consistent with experimental evidence suggesting that the presence of large particles leads to the formation of undesirable coagulum in the final product. [source] Evaluation of biological and chemical insecticide mixture against Aedes aegypti larvae and adults by thermal fogging in SingaporeMEDICAL AND VETERINARY ENTOMOLOGY, Issue 3 2001Y. K. Chung Abstract. To improve the operational efficiency of dengue vector control in Singapore, larvicide and adulticide were applied together by thermal fog generator (Agrofog® AF40). The mixture consisted of Bacillus thuringiensis var. israelensis (Vectobac® 12 AS) as biological larvicide at 1.5 L/ha and pirimiphos-methyl (Actellic® 50 EC) as adulticide at 100 g ai/ha, diluted 10-fold with water. Aerosol of this mixture was evaluated against the mosquito Aedes aegypti (L.) (Diptera: Culicidae) in bioassays using cages of 10 adult females exposed at heights of 0.3,2.4 m and distances of 3,12 m from the hand-held generator. Cups containing 200 mL water were treated at ground level by exposure to the aerosol application at the same distances from the generator. Subsequent larval bioassays on days 1, 7, 14, 21 and 28 post-spray involved exposing 20 larvae/cup for 48 h. Droplets had VMD 57 µm and female mosquitoes were killed by 2 s exposure to the aerosol at 3 m. We obtained 92,100% mortality of the adult mosquitoes and 100% control of larvae at 3 m distance, but only 10,13% mortality at 12 m from the fogger. In treated cups, larvae showed high mortality (92%) when exposed for 48 h even 1 month post-treatment. Results demonstrate the practical advantage of using this mixture of Vectobac® 12AS and Actellic® 50 EC for simultaneous control of Aedes adults and larvae, with prolonged larvicidal efficacy in treated containers. [source] Uniform Amplification of Phage with Different Growth Characteristics in Individual Compartments Consisting of Monodisperse Droplets,ANGEWANDTE CHEMIE, Issue 31 2010Ratmir Derda Dr. Jeder Klon zählt! Beim Phagen-Display gehen Klone, die das Phagenwachstum hemmende Liganden präsentieren, bei der Vervielfältigung verloren. In monodispersen Emulsionen, die mithilfe eines einfachen Mikrofluidiksystems erzeugt wurden, ist die Konkurrenz zwischen langsam (S) und schnell (R) wachsenden Phagen abgemildert, sodass das R/S-Verhältnis beibehalten bleibt. Die konkurrenzfreie Vervielfältigung von Phagen bewahrt Liganden, die im normalen Phagen-Display abhanden kommen. [source] Dilution-Free Analysis from Picoliter Droplets by Nano-Electrospray Ionization Mass Spectrometry,ANGEWANDTE CHEMIE, Issue 37 2009Verpackt, versandt und geliefert: Eine Methode wurde entwickelt, die den Inhalt wässriger Pfropfen, die in einer Ölphase immergiert sind, automatisch in eine wässrige Flussphase transferiert. Dies ermöglicht eine verdünnungslose Elektrospray(ESI)-Massenspektrometrieanalyse in der tröpfchenbasierten Mikrofluidik. [source] Production of Emulsions in High-Pressure Homogenizers , Part I: Disruption and Stabilization of DropletsCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 5 2003S. Tesch In continuous mechanical emulsification, disruption and stabilization of droplets determine the resulting droplet size and, thus, the emulsion's microstructure. Without the need of adding any stabilizer, w/o emulsions provide the possibility of a high viscosity of the continuous phase and, in consequence, of decreasing the probability of coalescence. The present work presents investigations on the production of w/o emulsions in high-pressure homogenizers: the different geometries of standard valve, microfluidizer and orifice valve are compared to each other with reference to disruption and stabilization of droplets. [source] ChemInform Abstract: Evidence for Superfluidity in para-Hydrogen Clusters Inside Helium-4 Droplets at 0.15 Kelvin.CHEMINFORM, Issue 2 2001Slava Grebenev Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Simulation of two-phase flow with sub-scale droplet and bubble effectsCOMPUTER GRAPHICS FORUM, Issue 2 2009Viorel Mihalef Abstract We present a new Eulerian-Lagrangian method for physics-based simulation of fluid flow, which includes automatic generation of sub-scale spray and bubbles. The Marker Level Set method is used to provide a simple geometric criterion for free marker generation. A filtering method, inspired from Weber number thresholding, further controls the free marker generation (in a physics-based manner). Two separate models are used, one for sub-scale droplets, the other for sub-scale bubbles. Droplets are evolved in a Newtonian manner, using a density-extension drag force field, while bubbles are evolved using a model based on Stokes' Law. We show that our model for sub-scale droplet and bubble dynamics is simple to couple with a full (macro-scale) Navier-Stokes two-phase flow model and is quite powerful in its applications. Our animations include coarse grained multiphase features interacting with fine scale multiphase features. [source] Epitaxial Sn1-xPbxS nanorods on iso-compositional thin filmsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 6 2010K. Bente Abstract Based on SnS (Herzenbergite) , SnPbS2 (Teallite) mixed crystals with orthorhombic layer structures, thin films and lawns of Sn1-xPbxS nanorods were produced using hot wall vacuum deposition method (HWVD). The lawn was formed onto the surface of an underlying thin Sn1-xPbxS film which is build by differently oriented blocks. The density of rods arranged like a lawn depends on the metal ratio and substrate temperature. X-ray and TEM analysis of the epitaxial material showed preferential (001) orientation perpendicular to the surface of the glass substrate. The roughness of the films measured by atomic force microscopy was in the range of Rq = 49.5,86.3 nm depending on lead concentration The rods were about 500 nm high and 300 nm in diameter. As revealed by TEM-EDX experiments the droplet at the tip of rods consists of tin. Therefore it is assumed the rods grew via a self-consuming vapor,liquid,solid (VLS) mechanism. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Facilitating the hyphenation of CIEF and MALDI-MS for two-dimensional separation of proteinsELECTROPHORESIS, Issue 15 2010Chang Cheng Abstract Both CIEF and MALDI-MS are frequently used in protein analysis, but hyphenation of the two has not been investigated proportionally. One of the major reasons is that the additives (such as carrier ampholytes and detergent) in CIEF severely suppress the MALDI-MS signal, which hampers the hyphenation of the two. In this paper, we develop a simple means to alleviate the above signal-suppressing effect. We first deposit 1,,L of water onto a MALDI-MS target, deliver a fraction of CIEF-separated protein (,0.1,,L) to the water droplet, evaporate the solvent, add 0.5,,L of MALDI matrix to the sample spot, dry the matrix and move the target plate to a MALDI-TOF-MS for mass spectrum measurement. We optimize the droplet volume and the laser-ablation region. Under the optimized conditions, we improve the S/N by two- to tenfold. We also apply this method for 2-D separations of standard proteins and apolipoprotein A,I, a membrane protein expressed in Escherichia coli cells. [source] Picoliter-volume aqueous droplets in oil: Electrochemical detection and yeast cell electroporationELECTROPHORESIS, Issue 10 2006Chunxiong Luo Abstract An electrochemical detection method was introduced for aqueous droplet analysis in oil phase of microfluidic devices. This method is based on the electrochemical signal difference between aqueous and oil. Applying a low alternating current,(AC) voltage to a couple of Au microelectrodes, this method can offer size information and ion concentration range from 0.02,mmol/L to 1,mol/L of tens of picoliter to nanoliter aqueous droplets. Alternatively, applying a relative high AC voltage (18,Vpp) at a frequency of 1,kHz leads to electroporation of yeast cells encapsulated into picoliter droplets. We believe that this simple technique is useful for a number of aqueous droplet-based chemical and biological analyses as well as cell electroporation. [source] Maternal size and age affect offspring sex ratio in the solitary egg parasitoid Anaphes nitensENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 1 2007Serena Santolamazza-Carbone Abstract In this study, the effects of maternal age, diet, and size on offspring sex ratio were investigated for the solitary egg parasitoid, Anaphes nitens Girault (Hymenoptera: Mymaridae), both outdoors, during the winter, and inside a climatic chamber under favourable constant conditions. During the winter of 2005,2006, each of seven groups containing 40 1-day-old females was mated and randomly distributed among two treatments: (treatment 1) a droplet of undiluted honey ad libitum + one fresh egg capsule of the snout beetle Gonipterus scutellatus Gyllenhal (Coleoptera: Curculionidae) as host; (treatment 2) drops of water + one fresh egg capsule of G. scutellatus. We recorded the lifetime fecundity, the daily sex allocation, and the lifetime offspring sex ratio to study the existence of a relationship with maternal characteristics. Moreover, we assessed the effect of location (outdoors vs. indoors) and group (groups are representative of early, mid, and late winter) on sex ratio. The most important factor that biased the sex ratio was maternal body size: larger females of both treatments produced more female offspring. As females of A. nitens could gain more advantage than males from body size, larger mothers have a higher fitness return if they produce more daughters. The effect of the treatment was significant: starved females produced more females. Location and group were not significant. Fecundity and sex ratio were age dependent. Old mothers that received honey (treatment 1) had fewer offspring and a more male-biased offspring sex ratio, probably due to reproductive senescence and sperm depletion. Starved females (treatment 2) experienced reproductive decline earlier, perhaps because they invested more energy in maintenance rather than in reproduction. [source] Contact Angle Analysis During the Electro-oxidation of Self-Assembled Monolayers Formed by n -OctadecyltrichlorosilaneADVANCED FUNCTIONAL MATERIALS, Issue 19 2010Nicole Herzer Abstract The electrochemical oxidation process of self-assembled monolayers formed by n -octadecyltrichlorosilane (OTS) molecules on silicon wafers has been studied in a droplet of water by means of in situ water contact angle measurements. The application of different bias voltages between the substrate and a counter electrode placed into the droplet resulted in changes of the chemical nature of the monolayer, which yielded a significant alteration of the surfaces properties. Due to the changes of the wetting properties of the monolayer during the electro-oxidation process a change in the contact angles of the water droplet is concomitantly observed. This allows the in situ monitoring of the electro-oxidation process for large modified areas of several millimeters in diameter. The chosen approach represents an easy way to screen the major parameters that influence the oxidation process. Afterwards, the oxidized regions are characterized by Fourier-transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS) measurements, and atomic force microscopy (AFM) investigations to obtain more information about the electro-oxidation process. The observations are correlated to experimental results obtained for oxidations performed on a smaller dimension range in the water meniscus of a conductive, biased AFM tip. A good correlation of the results in the different dimension ranges could be found. [source] Regulated expression by PPAR, and unique localization of 17,-hydroxysteroid dehydrogenase type 11 protein in mouse intestine and liverFEBS JOURNAL, Issue 18 2007Yasuhide Yokoi 17,-Hydroxysteroid dehydrogenase type 11 (17,-HSD11) is a member of the short-chain dehydrogenase/reductase family involved in the activation and inactivation of sex steroid hormones. We recently identified 17,-HSD11 as a gene that is efficiently regulated by peroxisome proliferator-activated receptor-, PPAR, in the intestine and the liver [Motojima K (2004) Eur J Biochem271, 4141,4146]. In this study, we characterized 17,-HSD11 at the protein level to obtain information about its physiologic role in the intestine and liver. For this purpose, specific antibodies against 17,-HSD11 were obtained. Western blotting analysis showed that administration of a peroxisome proliferator-activated receptor-, agonist induced 17,-HSD11 protein in the jejunum but not in the colon, and to a much higher extent than in the liver of mice. A subcellular localization study using Chinese hamster ovary cells and green fluorescent protein-tagged 17,-HSD11 showed that it was mostly localized in the endoplasmic reticulum under normal conditions, whereas it was concentrated on lipid droplets when they were induced. A pulse-chase experiment suggested that 17,-HSD11 was redistributed to the lipid droplets via the endoplasmic reticulum. Immunohistochemical analysis using tissue sections showed that 17,-HSD11 was induced mostly in intestinal epithelia and hepatocytes, with heterogeneous localization both in the cytoplasm and in vesicular structures. A subcellular fractionation study of liver homogenates confirmed that 17,-HSD11 was localized mostly in the endoplasmic reticulum when mice were fed a normal diet, but was distributed in both the endoplasmic reticulum and the lipid droplets of which formation was induced by feeding a diet containing a proliferator-activated receptor-, agonist. Taken together, these data indicate that 17,-HSD11 localizes both in the endoplasmic reticulum and in lipid droplets, depending on physiologic conditions, and that lipid droplet 17,-HSD11 is not merely an endoplasmic reticulum contaminant or a nonphysiologically associated protein in the cultured cells, but a bona fide protein component of the membranes of both intracellular compartments. [source] Fabrication of Microbeads with a Controllable Hollow Interior and Porous Wall Using a Capillary Fluidic DeviceADVANCED FUNCTIONAL MATERIALS, Issue 18 2009Sung-Wook Choi Abstract Poly(D,L -lactide-co-glycolide) (PLGA) microbeads with a hollow interior and porous wall are prepared using a simple fluidic device fabricated with PVC tubes, glass capillaries, and a needle. Using the fluidic device with three flow channels, uniform water-in-oil-in-water (W-O-W) emulsions with a single inner water droplet can be achieved with controllable dimensions by varying the flow rate of each phase. The resultant W-O-W emulsions evolve into PLGA microbeads with a hollow interior and porous wall after the organic solvent in the middle oil phase evaporates. Two approaches are employed for developing a porous structure in the wall: emulsion templating and fast solvent evaporation. For emulsion templating, a homogenized, water-in-oil (W/O) emulsion is introduced as the middle phase instead of the pure oil phase. Low-molecular-weight fluorescein isothiocyanate (FITC) and high-molecular-weight fluorescein isothiocyanate,dextran conjugate (FITC,DEX) is added to the inner water phase to elucidate both the pore size and their interconnectivity in the wall of the microbeads. From optical fluorescence microscopy and scanning electron microscopy images, it is confirmed that the emulsion-templated microbeads (W-W/O-W) have larger and better interconnected pores than the W-O-W microbeads. These microstructured microbeads can potentially be employed for cell encapsulation and tissue engineering, as well as protection of active agents. [source] Fabrication of a Superhydrophobic Surface from a Smectic Liquid-Crystal Defect ArrayADVANCED FUNCTIONAL MATERIALS, Issue 18 2009Yun Ho Kim Abstract A novel fabrication method is developed for the preparation of superhydrophobic surfaces. The procedure uses focal conic structures of semi-fluorinated smectic liquid crystals (LCs) whose periodic toric focal conic domains (TFCDs) are prepared on a surface modified substrate. Reactive ion etching (RIE) on the periodic TFCD surface leads to a superhydrophobic surface with a water contact angle of ,160° and a sliding angle of ,2° for a 10,µL water droplet. The results show that this phenomenon is due to the development of a dual-scale surface roughness arising from the nanoscale protuberance caused by applying the RIE process to the top of the microscale TFCD arrays. The unique surface behavior is further verified by demonstrating that RIE on a flat lamellar liquid crystal film, in which the director is aligned parallel with surface, results in a relatively low hydrophobicity as compared to when periodic TFCDs are subjected to REI. The observations made in this publication suggest that a new approach exists for selecting potential candidates of superhydrophic surface formation based on spontaneous self-assembly in smectic liquid-crystalline materials. [source] | |||||||||||||||||||||||||||||||||||||||||||||||||