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  1. Validation of lamellar body counts using three hematology analyzers.

    PubMed

    Lockwood, Christina M; Crompton, J Chance; Riley, Joan K; Landeros, Keith; Dietzen, Dennis J; Grenache, David G; Gronowski, Ann M

    2010-09-01

    The lamellar body count (LBC) represents an alternative method to the TDx-FLM II (Abbott Laboratories, Abbott Park, IL), which is planned to be discontinued, for assessing fetal lung maturity. Our objective was to validate the LBC on 3 hematology analyzers (Coulter LH 750 and Coulter Ac.T diff2, Beckman Coulter, Brea, CA; and Sysmex XE-2100, Sysmex, Mundelein, IL) to serve as a template for other laboratories attempting to perform in-house validation. Intra-assay and interassay coefficients of variation ranged from 1.7% to 21.8% and 1.9% to 7.1%, respectively, and all analyzers demonstrated excellent linearity. Whole blood and meconium were shown to interfere with LBCs, and specimens with these contaminants should be tested using phosphatidyl glycerol. With a TDx-FLM II cutoff of 55 mg/g or more and an LBC cutoff of 50,000/microL or more for maturity, concordance between the TDx-FLM II and the LBC on all instruments was poor (<80% in all cases). Concordance between hematology analyzers was excellent (>or=94%). When laboratories are performing in-house validations, they should not correlate LBC with TDx-FLM II results without outcome data. Correlation with another validated LBC method is preferred.

  2. Rechargeable 3 V Li cells using hydrated lamellar manganese oxide

    SciTech Connect

    Bach, S.; Pereira-Ramos, J.P.; Baffier, N.

    1996-11-01

    The synthesis and the electrochemical features of hydrated lamellar manganese oxides are reported. The authors use the reduction of aqueous permanganate solution by fumaric acid and the oxidation of manganese hydroxide by an aqueous permanganate solution to obtain sol-gel birnessite and classical X-exchanged birnessites (X = Li, Al, Na), respectively. The high oxidation state of Mn associated with the 2D character of the hot lattice allows high specific capacities (150 to 200 Ah/kg) available in the potential range of 4 to 2 V. Interlayer water provides the structural stability of the host lattice required for long cycling. Rechargeable two-electrode Li cells using starved or flooded electrolytes were built with the cathodic materials. The batteries exhibit a satisfactory behavior with a specific capacity of 160 Ah/kg recovered after 30 cycles at the C/20 discharge-charge rate for the sol-gel birnessite. This paper demonstrates an interest in cathodic materials based on oxides containing structural water for use in secondary Li batteries.

  3. Clipped random wave analysis of anisometric lamellar microemulsions

    NASA Astrophysics Data System (ADS)

    Choy, Dawen; Chen, Sow-Hsin

    2001-02-01

    Small-angle neutron scattering experiments were performed on C10E4-D2O-octane (where C10E4 is tetraethylene glycol monodecyl ether) anisometric microemulsions in the lamellar phase at a constant surfactant volume fraction of 20% and at the hydrophile-lipophile balance temperature of 22.5 °C. The results were analyzed using a clipped random wave model with a specific spectral distribution function developed by us previously. This enabled us to generate three-dimensional morphologies of the microemulsions, which showed clearly that in sufficiently anisometric microemulsions the oil-water interface was no longer connected. At large anisometry isolated regions of oil or water were found, and the transition from a bicontinuous structure at isometry to these isolated micelles far from isometry goes through an intermediate cylindrical morphology when the oil-to-water or water-to-oil ratio is around 4 to 1. We further computed the joint distribution function of the mean curvature H and Gaussian curvature K of the entire oil-water interface for each anisometric microemulsion. In particular, we show the distribution of , , and

    -2 for different isolated regions within an oil-rich microemulsion at an oil-to-water ratio of 85% to 15%. These distributions allowed us to prove that the isolated regions formed in highly anisometric microemulsions were small and had spherical topology.

  4. Clipped random wave analysis of anisometric lamellar microemulsions.

    PubMed

    Choy, D; Chen, S H

    2001-02-01

    Small-angle neutron scattering experiments were performed on C10E4-D2O-octane (where C10E4 is tetraethylene glycol monodecyl ether) anisometric microemulsions in the lamellar phase at a constant surfactant volume fraction of 20% and at the hydrophile-lipophile balance temperature of 22.5 degrees C. The results were analyzed using a clipped random wave model with a specific spectral distribution function developed by us previously. This enabled us to generate three-dimensional morphologies of the microemulsions, which showed clearly that in sufficiently anisometric microemulsions the oil-water interface was no longer connected. At large anisometry isolated regions of oil or water were found, and the transition from a bicontinuous structure at isometry to these isolated micelles far from isometry goes through an intermediate cylindrical morphology when the oil-to-water or water-to-oil ratio is around 4 to 1. We further computed the joint distribution function of the mean curvature H and Gaussian curvature K of the entire oil-water interface for each anisometric microemulsion. In particular, we show the distribution of , , and

    -(2) for different isolated regions within an oil-rich microemulsion at an oil-to-water ratio of 85% to 15%. These distributions allowed us to prove that the isolated regions formed in highly anisometric microemulsions were small and had spherical topology.

  5. Cystoid foveal oedema in symptomatic inner lamellar macular holes.

    PubMed

    Ophir, A; Fatum, S

    2009-09-01

    Inner lamellar macular hole (LMH) was considered a relatively risk-free condition that rarely progresses or worsens. Nowadays, at the optical coherence tomography (OCT) era, increasing evidence seems to position it differently. The aim of the study was to describe morphologic abnormalities associated with symptomatic LMH using OCT that may explain reduced visual acuity in these patients. In a retrospective study on consecutive symptomatic patients with LMH, OCT scans were compared with normal controls. Analysis was referred to LMH-associated abnormalities at the residual fovea, mainly cystoid spaces that manifested as cystoid foveal oedema. A total of 22 eyes of 20 patients (mean age, 68 years; range, 22-94) were included in the study. Best-corrected visual acuity ranged from 6/9 to 6/120. Cystoid foveal oedema that contained cystoid spaces of various sizes was found in 21 (95%) of eyes; an intraretinal split was seen in 18 eyes (82%) and epiretinal membrane was detected in 16 eyes (73%). The appearance of cystoid oedema at the residual fovea in symptomatic LMHs may explain in part a reduced visual acuity and/or metamorphopsia. The old notion on the low incidence of LMH progression may probably be related in part to (a) lower diagnostic accuracy before OCT was available and to (b) the already spontaneously peeled inner limiting membrane. Further studies are required to verify these observations, which may merit clinical and surgical considerations.

  6. Lower lid retraction in thyroid orbitopathy: lamellar shortening or proptosis?

    PubMed

    Rajabi, Mohammad Taher; Jafari, Hajar; Mazloumi, Mehdi; Tabatabaie, Syed Ziaeddin; Rajabi, Mohammad Bagher; Hasanlou, Narges; Abtahi, Seyed-Mojtaba; Goldberg, Robert A

    2014-08-01

    To investigate any correlation between lower lid retraction and proptosis and also between lower lid retraction and lamellar length, as measured by fornix depth, in patients with thyroid eye disease (TED). One hundred and sixty-six eyes of 83 patients with TED were enrolled. The inferior fornix depth, Hertel exophthalmometry measurement, clinical activity score, and lower lid position were the main outcome variables. The correlation between lower lid position measurement and Hertel measurements and also between the lower lid position measurement and inferior fornix depth were evaluated using ANOVA and Pearson's tests. The mean age of subjects in patients with and without lid retraction was 42.8 ± 1.5 and 47.7 ± 1.6 years, respectively (P = 0.4). The inferior fornix depth in patients with and without lower lid retraction was 11.8 ± 1.5 and 11.8 ± 1.3 mm, respectively (P = 0.960). Pearson's analysis showed a significant correlation between the degree of proptosis and lower lid retraction in TED patients (P = 0.01). However, no significant correlation was found between the level of lower lid retraction and the fornix depth (P = 0.87). The main cause of lower lid retraction in TED is proptosis. The beneficial effect of orbital decompression on improvement of lower lid retraction must be considered during a stepwise surgical approach in TED patients.

  7. Unique effects of aerosol OT lamellar structures on the dynamics of guest molecules.

    PubMed

    De, Dipanwita; Datta, Anindya

    2013-06-25

    The behavior of lamellar structures of Aerosol OT (AOT) as hosts, vis-à-vis the flexible normal micelles and rigid nanochannels of Nafion membranes, has been investigated with two different fluorophores, [2,2'-bipyridyl]-3,3'-diol (BP(OH)2) and coumarin 102 (C102). Surprisingly, for BP(OH)2, a rise time is observed at intermediate emission wavelengths and not in the red edge of the fluorescence spectrum. A shoulder at 525 nm is observed in time resolved emission spectra (TRES) at initial times of BP(OH)2 in AOT lamellar structures. This feature is the signature of the monoketo (MK) tautomer, observed for the first time in a microheterogeneous medium. Also, the usually ultrafast single proton transfer in BP(OH)2 is retarded to an considerable extent in lamellar structures. The potential of this medium in promoting unusual intermediates is thus highlighted. This property may be ascribed to the rigidity of lamellar structures, compared to hosts such as regular micelles. However, studies using another fluorophore, coumarin 102 (C102), brings out the fact that these structures are significantly different from the rigid host, Nafion, as well. The absence of excited state proton transfer (ESPT) in this molecule in AOT lamellar structures indicates that it is not protonated, unlike in Nafion. Thus, the interfacial pH of lamellar structures is found to be significantly greater than that of Nafion nanochannels. From the time dependent Stokes shift (TDSS) of the emission spectra of C102, the relaxation time (0.85 ns) of interfacial water in lamellar structures is found to be an order of magnitude faster than that observed in Nafion nanochannels, in which H3O(+) ions have been substituted by different cations. Hence, this study demonstrates that AOT lamellar structures are rather unique hosts and that they behave very differently from conventional rigid and flexible hosts such as normal micelles and Nafion, respectively.

  8. A ROLE FOR DIACYLGLYCEROL IN ANNEXIN A7-MEDIATED FUSION OF LUNG LAMELLAR BODIES

    PubMed Central

    Chander, Avinash; Chen, Xiao-Liang; Naidu, Devendra G

    2007-01-01

    Lung surfactant secretion in alveolar type II cells occurs following lamellar body fusion with plasma membrane. Annexin A7 is a Ca2+-dependent membrane-binding protein that is postulated to promote membrane fusion during exocytosis in some cell types including type II cells. Since annexin A7 preferably binds to lamellar body membranes, we postulated that specific lipids could modify the mode of annexin A7 interaction with membranes and its membrane fusion activity. Initial studies with phospholipid vesicles containing phosphatidylserine and other lipids showed that certain lipids affected protein interaction with vesicle membranes as determined by change in protein tryptophan fluorescence, protein interaction with trans membranes, and by protein sensitivity to limited proteolysis. The presence of signaling lipids, diacylglycerol or phosphatidylinositol-4,5-bisphosphate, as minor components also modified the lipid vesicle effect on these characteristics and membrane fusion activity of annexin A7. In vitro incubation of lamellar bodies with diacylglycerol or phosphatidylinositol-4,5-bisphosphate caused their enrichment with either lipid, and increased the annexin A7 and Ca2+-mediated fusion of lamellar bodies. Treatment of isolated lung lamellar bodies with phosphatidylinositol- or phosphatidylcholine phospholipase C to increase diacylglycerol, without or with preincubation with phosphatidylinositol-4,5-bisphosphate, augmented the fusion activity of annexin A7. Thus, increased diacylglycerol in lamellar bodies following cell stimulation with secretagogues may enhance membrane fusion activity of annexin A7. PMID:17765009

  9. Lecithin based lamellar liquid crystals as a physiologically acceptable dermal delivery system for ascorbyl palmitate.

    PubMed

    Gosenca, Mirjam; Bešter-Rogač, Marija; Gašperlin, Mirjana

    2013-09-27

    Liquid crystalline systems with a lamellar structure have been extensively studied as dermal delivery systems. Ascorbyl palmitate (AP) is one of the most studied and used ascorbic acid derivatives and is employed as an antioxidant to prevent skin aging. The aim of this study was to develop and characterize skin-compliant dermal delivery systems with a liquid crystalline structure for AP. First, a pseudoternary phase diagram was constructed using Tween 80/lecithin/isopropyl myristate/water at a Tween 80/lecithin mass ratio of 1/1, and the region of lamellar liquid crystals was identified. Second, selected unloaded and AP-loaded lamellar liquid crystal systems were physicochemically characterized with polarizing optical microscopy, small-angle X-ray scattering, differential scanning calorimetry, and rheology techniques. The interlayer spacing and rheological parameters differ regarding quantitative composition, whereas the microstructure of the lamellar phase was affected by the AP incorporation, resulting either in additional micellar structures (at 25 and 32 °C) or being completely destroyed at higher temperature (37°C). After this, the study was oriented towards in vitro cytotoxicity evaluation of lamellar liquid crystal systems on a keratinocyte cell line. The results suggest that the lamellar liquid crystals that were developed could be used as a physiologically acceptable dermal delivery system. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. In vitro fusion of lung lamellar bodies and plasma membrane is augmented by lung synexin.

    PubMed

    Chander, A; Wu, R D

    1991-11-05

    Lamellar bodies of lung epithelial type II cells undergo fusion with plasma membrane prior to exocytosis of surfactant into the alveolar lumen. Since synexin from adrenal glands promotes aggregation and fusion of chromaffin granules, we purified synexin-like proteins from bovine lung cytosolic fraction, and evaluated their effect on the fusion of isolated lamellar bodies and plasma membrane fractions. Synexin activity, which co-purified with an approx. 47 kDa protein (pI 6.8), was assessed by following calcium-dependent aggregation of liposomes prepared from a mixture of phosphatidylcholine:phosphatidylserine (PC:PS, 3:1, mol/mol). Lung synexin caused aggregation of liposomes approximating lung surfactant lipid-like composition, isolated lamellar bodies, or isolated plasma membrane fraction. Lung synexin promoted fusion only in the presence of calcium. It augmented fusion between lamellar bodies and plasma membranes, lamellar bodies and liposomes, or between two populations of liposomes. However, selectivity with regard to synexin-mediated fusion was observed as synexin did not promote fusion between plasma membrane and liposomes, or between liposomes of surfactant lipid-like composition and other liposomes. These observations support a role for lung synexin in membrane fusion between the plasma membrane and lamellar bodies during exocytosis of lung surfactant, and suggest that such fusion is dependent on composition of interacting membranes.

  11. Comparison of Long-term Clinical Outcomes between Descemet's Stripping Automated Endothelial Keratoplasty and Penetrating Keratoplasty in Patients with Bullous Keratopathy

    PubMed Central

    Kim, Sung Eun; Lim, Sung A; Byun, Yong-Soo

    2016-01-01

    Purpose To compare 2-year clinical outcomes of Descemet's stripping automated endothelial keratoplasty (DSAEK) and penetrating keratoplasty (PK) in patients with bullous keratopathy. Methods A retrospective chart review was performed to obtain 2 years of follow-up data of DSAEK or PK at a single center from March 2009 to September 2012. The study comprised 15 eyes of DSAEK and 11 eyes of PK. Outcome measures included best-corrected visual acuity (BCVA), spherical and keratometric changes, central corneal thickness, endothelial cell density, intraocular pressure, and postoperative complications. Graft survival rate was assessed by Kaplan-Meier survival analysis. Results There were no differences in patient baseline characteristics between the two groups. At postoperative 2 years, better BCVA of 0.69 ± 0.51 logarithm of the minimum angle of resolution (logMAR) was found after DSAEK compared to 0.88 ± 0.48 logMAR after PK. Refractive cylinder in DSAEK and PK was −2.60 ± 1.53 and −6.00 ± 1.05 diopters (D), respectively, and keratometric cylinder was 3.27 ± 3.70 and 6.34 ± 3.51 D, respectively, at postoperative 2 years. The difference of mean spherical equivalents between postoperative 1 month and 2 years was 0.84 D after DSAEK and 2.05 D after PK. A hyperopic shift of 1.17 D was present after 2 years of DSAEK. The mean endothelial cell density at postoperative 2 years was 1,548 ± 456 cells/mm2 for DSAEK and 1,052 ± 567 cells/mm2 for PK, with a cell loss of 19.96% vs. 52.38%, respectively when compared to postoperative 1 month. No significant difference in central corneal thickness was found between DSAEK and PK (592 ± 75 vs. 563 ± 90 µm, respectively). Finally, the 2-year survival rate did not differ significantly between DSAEK and PK (93.3% vs. 81.8%, respectively, p = 0.344). Conclusions Compared to PK, DSAEK provided more stable refractive errors with better visual outcome, lower endothelial cell loss, and a lower rate of graft rejection at

  12. Elasticity and hydrodynamic properties of ``doped solvent dilute'' lamellar phases

    NASA Astrophysics Data System (ADS)

    Nallet, Frédéric; Roux, Didier; Quilliet, Catherine; Fabre, Pascale; Milner, Scott T.

    1994-09-01

    The equilibrium fluctuations and weakly out-of-equilibrium relaxation properties of “doped solvent" dilute lamellar phases are investigated, both theoretically and experimentally, in the low-frequency, long-wavelength limit. The physical system of interest is a three-component smectic A lyotropic liquid crystal where surfactant bilayers infinite in extent are periodically stacked along one direction in space and separated by a colloidal solution. Two experimentally relevant modes are found in the lowest frequency part of the fluctuation spectrum of such multicomponent systems. Both are associated to the relaxation of coupled layer displacement and colloid concentration waves. In the limit of small coupling, one mode is close to the well-known undulation/baroclinic mode of two-component lamellar phases, while the other corresponds to the Brownian diffusive motion of the colloid in an anisotropic medium. Elastic constants of the smectic liquid crystal and diffusion parameters of the colloidal solution may be deduced from a measurement of the anisotropic dispersion relation of these two modes, as illustrated by dynamic light scattering experiments on the ferrosmectic system. Les fluctuations à l'équilibre ainsi que la relaxation des états légèrement en dehors de l'équilibre des phases lamellaires à “solvant dopé” sont étudiées, aussi bien d'un point de vue théorique qu'expérimental, dans la limite de basses fréquences et de grandes longueurs d'onde. Les systèmes décrits sont des cristaux-liquides smectiques A lyotropes formés de trois constituants : un tensioactif en solution dans une suspension colloïdale forme des bicouches de grande extension latérale qui s'empilent de façon périodique le long d'une direction dans l'espace. Avec de tels systèmes anisotropes et à plusieurs constituants deux modes présents dans la partie à basse fréquence du spectre des fluctuations (associés à la relaxation d'ondes, couplées, de concentration collo

  13. Dynamics of edge dislocations in a sheared lamellar mesophase.

    PubMed

    Kumaran, V

    2013-10-07

    The dynamics and interactions of edge dislocations in a nearly aligned sheared lamellar mesophase is analysed to provide insights into the relationship between disorder and rheology. First, the mesoscale permeation and momentum equations for the displacement field in the presence of external forces are derived from the model H equations for the concentration and momentum field. The secondary flow generated due to the mean shear around an isolated defect is calculated, and the excess viscosity due to the presence of the defect is determined from the excess energy dissipation due to the secondary flow. The excess viscosity for an isolated defect is found to increase with system size in the cross-stream direction as L(3/2) for an isolated defect, though this divergence is cut-off due to interactions in a defect suspension. As the defects are sheared past each other due to the mean flow, the Peach-Koehler force due to elastic interaction between pairs of defects is found to cause no net displacement relative to each other as they approach from large separation to the distance of closest approach. The equivalent force due to viscous interactions is found to increase the separation for defects of opposite sign, and decrease the separation for defects of same sign. During defect interactions, we find that there is no buckling instability due to dilation of layers for systems of realistic size. However, there is another mechanism, which is the velocity difference generated across a slightly deformed bilayer due to the mean shear, which could result in the creation of new defects.

  14. Surface affinity role in graphoepitaxy of lamellar block copolymers

    NASA Astrophysics Data System (ADS)

    Claveau, Guillaume; Quemere, Patrick; Argoud, Maxime; Hazart, Jerome; Barros, Patricia Pimenta; Sarrazin, Aurelien; Posseme, Nicolas; Tiron, Raluca; Chevalier, Xavier; Nicolet, Celia; Navarro, Christophe

    2016-07-01

    Overcoming the optical limitations of 193-nm immersion lithography can be achieved using directed self-assembly (DSA) of block-copolymers (BCPs) as a low-cost and versatile complementary technique. The goal of this paper is to investigate the potential of DSA to address line and space (L/S) high-resolution patterning by performing the density multiplication of lines with the graphoepitaxy approach. As surface affinity is a key parameter in self-assembly, three variations, or "flavors," of DSA template affinity are investigated regarding several success criteria such as morphology control or defectivity. More precisely, both the methodology to register DSA defects and the impact of process parameters on defectivity are detailed. Using the 300-mm pilot line available in LETI and Arkema's advanced materials, we investigate process optimization of DSA line/space patterning of a 38-nm period lamellar PS-b-PMMA BCP (L38). Our integration scheme is based on BCP self-assembly inside organic hard mask guiding patterns obtained using 193i-nm lithography. Defect analysis coupled with the fine tuning of process parameters (annealing, brush material) provided the optimum conditions for the L38 self-assembly. Using such conditions, DSA using the three affinity flavors is investigated by means of SEM top-view and cross-section review. Lithographic performances of one selected flavor are then evaluated with the comparison of process windows function of either commensurability, morphology, or roughness. This work is meant as a guideline for the graphoepitaxy optimization of materials and process parameters on a 300-mm platform.

  15. Structure, stability, and thermodynamics of lamellar DNA-lipid complexes.

    PubMed Central

    Harries, D; May, S; Gelbart, W M; Ben-Shaul, A

    1998-01-01

    We develop a statistical thermodynamic model for the phase evolution of DNA-cationic lipid complexes in aqueous solution, as a function of the ratios of charged to neutral lipid and charged lipid to DNA. The complexes consist of parallel strands of DNA intercalated in the water layers of lamellar stacks of mixed lipid bilayers, as determined by recent synchrotron x-ray measurements. Elastic deformations of the DNA and the lipid bilayers are neglected, but DNA-induced spatial inhomogeneities in the bilayer charge densities are included. The relevant nonlinear Poisson-Boltzmann equation is solved numerically, including self-consistent treatment of the boundary conditions at the polarized membrane surfaces. For a wide range of lipid compositions, the phase evolution is characterized by three regions of lipid to DNA charge ratio, rho: 1) for low rho, the complexes coexist with excess DNA, and the DNA-DNA spacing in the complex, d, is constant; 2) for intermediate rho, including the isoelectric point rho = 1, all of the lipid and DNA in solution is incorporated into the complex, whose inter-DNA distance d increases linearly with rho; and 3) for high rho, the complexes coexist with excess liposomes (whose lipid composition is different from that in the complex), and their spacing d is nearly, but not completely, independent of rho. These results can be understood in terms of a simple charging model that reflects the competition between counterion entropy and inter-DNA (rho < 1) and interbilayer (rho > 1) repulsions. Finally, our approach and conclusions are compared with theoretical work by others, and with relevant experiments. PMID:9649376

  16. Dynamics of edge dislocations in a sheared lamellar mesophase

    NASA Astrophysics Data System (ADS)

    Kumaran, V.

    2013-10-01

    The dynamics and interactions of edge dislocations in a nearly aligned sheared lamellar mesophase is analysed to provide insights into the relationship between disorder and rheology. First, the mesoscale permeation and momentum equations for the displacement field in the presence of external forces are derived from the model H equations for the concentration and momentum field. The secondary flow generated due to the mean shear around an isolated defect is calculated, and the excess viscosity due to the presence of the defect is determined from the excess energy dissipation due to the secondary flow. The excess viscosity for an isolated defect is found to increase with system size in the cross-stream direction as L3/2 for an isolated defect, though this divergence is cut-off due to interactions in a defect suspension. As the defects are sheared past each other due to the mean flow, the Peach-Koehler force due to elastic interaction between pairs of defects is found to cause no net displacement relative to each other as they approach from large separation to the distance of closest approach. The equivalent force due to viscous interactions is found to increase the separation for defects of opposite sign, and decrease the separation for defects of same sign. During defect interactions, we find that there is no buckling instability due to dilation of layers for systems of realistic size. However, there is another mechanism, which is the velocity difference generated across a slightly deformed bilayer due to the mean shear, which could result in the creation of new defects.

  17. Surface affinity role in graphoepitaxy of lamellar block copolymers

    NASA Astrophysics Data System (ADS)

    Claveau, G.; Quemere, P.; Argoud, M.; Hazart, J.; Pimenta Barros, P.; Sarrazin, A.; Posseme, N.; Tiron, R.; Chevalier, X.; Nicolet, C.; Navarro, C.

    2016-03-01

    Overcoming the optical limitations of 193nm immersion lithography can be achieved using Directed Self Assembly (DSA) of block-copolymers (BCPs) as a low-cost and versatile complementary technique. The goal of this paper is to investigate the potential of DSA to address line and space (L/S) high resolution patterning by performing the density multiplication of lines with the graphoepitaxy approach. As surface affinity is a key parameter in self-assembly, three variations, or "flavors", of DSA template affinity are investigated regarding several success criteria such as morphology control or defectivity. More precisely, both the methodology to register DSA defects and the impact of process parameters on defectivity are detailed. Using the 300mm pilot line available in LETI and Arkema's advanced materials, we investigate process optimization of DSA line/space patterning of a 38nm period lamellar PS-b-PMMA BCP (L38). For this study, our integration scheme, depicted in figure 2-1, is based on BCP self-assembly inside organic hard mask guiding patterns obtained using 193i nm lithography. Defect analysis coupled with the fine tuning of process parameters (annealing, brush material) provided the optimum conditions for the L38 self-assembly. Using such conditions, DSA using the three affinity flavors is investigated by means of SEM top-view and cross-section review. Lithographic performances of one selected flavor are then evaluated with the comparison of Process Windows (PWs) function of either commensurability, morphology or LWR. This work is a first step in finding the best process for an industrial graphoepitaxy approach.

  18. A Preferable Method for the Formation of Vesicles from Lamellar Liquid Crystals Using Chemical Additives.

    PubMed

    Enomoto, Yasutaka; Imai, Yoko; Tajima, Kazuo

    2017-01-01

    We present a method for vesicle formation from lamellar liquid crystals (LCs) using a cationic amphiphilic substance, namely 2-hydroxyethyl di(alkanol)oxyethyl methylammonium methylsulfate (DEAE). Vesicle formation from the DEAE lamellar dispersion occurred via a two-step chemical addition. This method required neither additional mechanical energy nor the use of special solvents. The transition was solubilized using an organic substance (e.g., limonene) in the lamellar DEAE LC, after which, a small amount of inorganic salt was added to the solubilized lamellar LC dispersion with gentle stirring. The viscosity of the DEAE dispersion following salt addition decreased sharply from 10(5) mPa·s to 10(2) mPa·s, and the DEAE dispersion was converted into a high fluidity liquid. Several organic substances were examined as potential solubilizates to initiate the lamellar-vesicle transition. Inorganic salts were also examined as transition triggers using various types of electrolytes; only neutral salts were effective as trigger additives. Dissociation of inorganic salts yielded anions, which inserted between the DEAE bilayer membranes and induced OH(-) ion exchange. In addition, a number of cations simultaneously formed ion pairs with the DEAE counter ions (CH3SO4(-) ions). However, as the amount of solubilized organic substances in the DEAE bilayer membrane decreased over time, the vesicles were transformed into lamellar LCs once again. The DEAE states in each step were measured by monitoring the zeta potential, pH, viscosity, and by examination of scanning electron microscopy and atomic force microscopy images. A possible molecular mechanism for the lamellar-vesicle transition of DEAE was proposed.

  19. Vacuolar ATPase Regulates Surfactant Secretion in Rat Alveolar Type II Cells by Modulating Lamellar Body Calcium

    PubMed Central

    Chintagari, Narendranath Reddy; Mishra, Amarjit; Su, Lijing; Wang, Yang; Ayalew, Sahlu; Hartson, Steven D.; Liu, Lin

    2010-01-01

    Lung surfactant reduces surface tension and maintains the stability of alveoli. How surfactant is released from alveolar epithelial type II cells is not fully understood. Vacuolar ATPase (V-ATPase) is the enzyme responsible for pumping H+ into lamellar bodies and is required for the processing of surfactant proteins and the packaging of surfactant lipids. However, its role in lung surfactant secretion is unknown. Proteomic analysis revealed that vacuolar ATPase (V-ATPase) dominated the alveolar type II cell lipid raft proteome. Western blotting confirmed the association of V-ATPase a1 and B1/2 subunits with lipid rafts and their enrichment in lamellar bodies. The dissipation of lamellar body pH gradient by Bafilomycin A1 (Baf A1), an inhibitor of V-ATPase, increased surfactant secretion. Baf A1-stimulated secretion was blocked by the intracellular Ca2+ chelator, BAPTA-AM, the protein kinase C (PKC) inhibitor, staurosporine, and the Ca2+/calmodulin-dependent protein kinase II (CaMKII), KN-62. Baf A1 induced Ca2+ release from isolated lamellar bodies. Thapsigargin reduced the Baf A1-induced secretion, indicating cross-talk between lamellar body and endoplasmic reticulum Ca2+ pools. Stimulation of type II cells with surfactant secretagogues dissipated the pH gradient across lamellar bodies and disassembled the V-ATPase complex, indicating the physiological relevance of the V-ATPase-mediated surfactant secretion. Finally, silencing of V-ATPase a1 and B2 subunits decreased stimulated surfactant secretion, indicating that these subunits were crucial for surfactant secretion. We conclude that V-ATPase regulates surfactant secretion via an increased Ca2+ mobilization from lamellar bodies and endoplasmic reticulum, and the activation of PKC and CaMKII. Our finding revealed a previously unrealized role of V-ATPase in surfactant secretion. PMID:20169059

  20. Orientation of lamellar phases of lyotropic multicomponent mixtures, based on cetyltrimethylammonium bromide cationic detergent, in magnetic field

    NASA Astrophysics Data System (ADS)

    Kiirend, E. O.; Chumakova, S. P.; Pekhk, T. I.; Ivanov, N. R.

    2013-11-01

    The orientation of the lamellar phases in lyotropic systems based on cetyltrimethylammonium bromide (CTAB) detergent has been studied by polarization optical microscopy and 2H-NMR methods. The lamellar lyotropics studied are shown to align under a strong magnetic field of 11.7 T. According to 2H-NMR data, structural transformations of the lamellar phases may occur during orientation when the sample temperature increases.

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