bluuebunny/crossref_metadata_2025_split huggingface dataset:
Photoelectric Response of Self Assembled Films of Bacterio-Rhodopsin Purple Membrane Integrated on Silicon
Authors: Ricceri D. , Scicolone G. , Di Marco O. , Conoci S. , Pignataro B. , Coffa S. 
Published: June 2019

AbstractBacterio-rhodopsin purple membrane (PM) thin films have been prepared by selfassembling (SA) technique. Morphological properties of the layers were inspected by Scanning Electron Microscopy (SEM) and Scanning Force Microscopy (SFM) highlighting the presence of densely packed PM films. Reflectance Uv-vis spectra on these films revealed the typical bR absorption at 570 nm. By using a tungsten lamp illuminations (250-350 mW) chopped at 0.5Hz, photoelectric responses were detected. Differential (light-on and light-off) photocurrent signals of up to 1 μA/cm2 were obtained upon light exposure.
Lipid Membranes: Biological Inspiration for Micro and Nano Encapsulation Technologies, Especially Drug Delivery
Authors: Needham David 
Published: June 2019

AbstractOur approach to biologically inspired materials and materials systems recognizes biology (at all scale levels) as a series ofproductsthat fulfill particular functions. It then links material composition and structure tofunctionthroughpropertiesand therefore attempts to bring mechanism to processes andfunctionsof biology. As an example of this approach we have focused on the lipid bilayer membranes of blood cells, like erythrocytes and neutrophils, as a bioinspired material system for drug delivery leading to the creation of waxy, nano capsules called liposomes that can be triggered to release their drug by hyperthermia. Thus, while Nature's encapsulation technology provides the inspiration, the mechanism of drug release is non-natural. The necessary design parameters for the required functions of drug encapsulation, i.e. drug retention, circulation half life, and eventual thermally-triggered drug release, were obtained through extensive experimentation and modeling of artificial lipid vesicles by us and others, with much of the mechanical and thermomechanical properties, molecular exchange, andin vitroperformance investigated by a direct micropipet manipulation technique. With respect to cancer chemotherapy, the unmet need for primary solid tumors is to deliver more drug to the tumor tissue thereby reducing the tumor size (debulking) while at the same time reducing toxic side effects. It is with these criteria in mind that we developed the temperature-triggered liposome for the treatment of solid tumors. This paper then, describes this liposome development and its performancein vivo, where, in some cases, the temperature-triggered release of drug directly in the blood stream and tumor resulted in complete tumor regression. What this example also shows is that through material property measurement and modeling, new insights into Nature's functions and designs can be discovered in areverse engineeringprocess from which new products can then beforward engineeredto solve engineering and product problems in health, technology, and the environment.
Direct Observation of Calcium Oxalate Monohydrate Precipitation at Phospholipid Monolayers with Brewster Angle Microscopy
Authors: Benítez Isa O. , Backov Rénal , Khan Saeed R. , Talham Daniel R. 
Published: June 2019

AbstractThe precipitation of calcium oxalate monohydrate (COM) at phospholipid monolayers has been observed in-situ by Brewster angle microscopy (BAM). A monolayer of 1,2-dipalmitoylsn-glycero-3-phosphocholine (DPPC) compressed to a LC state over a calcium oxalate subphase shows the growth of COM as very bright spots. The identity of COM was confirmed in a transferred film by scanning electron microscopy. BAM can also be used to determine where COM precipitates when the monolayer has two phases at equilibrium. Monolayers of DPPC and 1,2-dipalmitoyl-sn-glycero-3-[phospho-rac-(1-glycerol)] (DPPG) crystallize COM at phase boundaries. In addition, phase separated binary phospholipid mixtures of DPPC and 1,2-dimiristoyl-sn-glycero-3-phosphocholine (DMPC) have been prepared and monitored by BAM. The crystal growth in this case is confined to domains of DPPC due to its ability to form a liquid condensed phase.
Dextran Grafted Silicon Substrates: Preparation, Characterization And Biomedical Applications
Authors: Ombelli Michela , Eckmann David M. , Composto Russell J. 
Published: June 2019

AbstractBiodevices used in the cardiovascular system suffer from well-known problems associated with surface-induced gas embolism and thrombosis. In order to improve the biocompatibility of these devices, biomimetic coatings show good promise. We recently synthesized a coating layer of dextran, a relatively simple and well characterized neutral polysaccharide, with the purpose of mimicking the cells' glycocalyx layer, that prevents non-specific cells-protein interactions. Systematic physical chemical characterization was performed on coatings obtained both from commonly used polydisperse dextrans and low-dispersity dextrans in the 1-100 kDalton molecular weight range.We have combined standard surface analysis techniques, such as ellipsometry, contact angle measurements and AFM, with less traditional vibrational spectroscopy techniques in the characterization of our biomimetic coatings. FTIR, micro-FTIR and micro-Raman spectroscopies were utilized to correlate the conformational and molecular aspects of the grafted poly- and monodisperse dextran chains to their attractive biological properties.
Cytocompatibility and Material Properties of Poly-carbonate Urethane/Carbon Nanofiber Composites for Neural Applications
Authors: McKenzie Janice L. , Waid Michael C. , Shi Riyi , Webster Thomas J. 
Published: June 2019

AbstractCarbon nanofibers possess excellent conductivity properties, which may be beneficial in the design of more effective neural prostheses, however, limited evidence on their cytocompatibility properties exists. The objective of the present in vitro study was to determine cytocompatibility and material properties of formulations containing carbon nanofibers to predict the gliotic scar tissue response. Poly-carbonate urethane was combined with carbon nanofibers in varying weight percentages to provide a supportive matrix with beneficial bulk electrical and mechanical properties. The substrates were tested for mechanical properties and conductivity. Astrocytes (glial scar tissue-forming cells) were seeded onto the substrates for adhesion. Results provided the first evidence that astrocytes preferentially adhered to the composite material that contained the lowest weight percentage of carbon nanofibers. Positive interactions with neurons, and, at the same time, limited astrocyte functions leading to decreased gliotic scar tissue formation are essential for increased neuronal implant efficacy.
Enhanced Osteoblast Adhesion on a Novel Hydroxyapatite Coating
Authors: Sato Michiko , Slamovich Elliott B. , Webster Thomas J. 
Published: June 2019

AbstractPlasma spray deposition of hydroxyapatite (HA) onto a titanium implant involves high temperatures that may alter HA crystallinity and induce cracks in the coating. For this reason, the objective of this study was to design a novel HA coating material and method. Titanium was coated with HA, titania, and Poly (dl-lactic-glycolic acid) (PLGA) using sol-gel processing. The biocompatibility of the HA coating in the present study was compared to that of a plasmasprayed HA coating. Results of this study showed that osteoblast adhesion was promoted more in the HA coating proposed in this study than on the plasma-sprayed HA coating. In addition, hydrothermal treatment of the coating appeared to improve the biocompatibility of the HA coating. Since osteoblast adhesion is a necessary requirement for increased bonding of an implant to juxtaposed bone, these results support that hydrothermally sol-gel processed HA may be an optimal implant coating material and method.
Cytocompatibility of Carbon Nanofiber Materials for Neural Applications
Authors: McKenzie Janice L. , Waid Michael C. , Shi Riyi , Webster Thomas J. 
Published: June 2019

AbstractSince the cytocompatibility of carbon nanofibers with respect to neural applications remains largely uninvestigated, the objective of the present in vitro study was to determine cytocompatibility properties of formulations containing carbon nanofibers. Carbon fiber substrates were prepared from four different types of carbon fibers, two with nanoscale diameters (nanophase, or less than or equal to 100 nm) and two with conventional diameters (or greater than 200 nm). Within these two categories, both a high and a low surface energy fiber were investigated and tested. Astrocytes (glial scar tissue-forming cells) and pheochromocytoma cells (PC-12; neuronal-like cells) were seeded separately onto the substrates. Results provided the first evidence that astrocytes preferentially adhered on the carbon fiber that had the largest diameter and the lowest surface energy. PC-12 cells exhibited the most neurites on the carbon fiber with nanodimensions and low surface energy. These results may indicate that PC-12 cells prefer nanoscale carbon fibers while astrocytes prefer conventional scale fibers. A composite was formed from poly-carbonate urethane and the 60 nm carbon fiber. Composite substrates were thus formed using different weight percentages of this fiber in the polymer matrix. Increased astrocyte adherence and PC-12 neurite density corresponded to decreasing amounts of the carbon nanofibers in the poly-carbonate urethane matrices. Controlling carbon fiber diameter may be an approach for increasing implant contact with neurons and decreasing scar tissue formation.
Monodisperse Mesoporous Microparticles Prepared by Evaporation-Induced Self Assembly Within Aerosols
Authors: Rathod Shailendra , Rama Rao G. V. , Andrzejewski Brett , López Gabriel P. , Ward Timothy L. , Brinker C. Jeffrey , Datye Abhaya K. 
Published: June 2019

AbstractEvaporation induced self assembly (EISA) within microdroplets produced by a vibrating orifice aerosol generator (VOAG) has been used to produce monodisperse mesoporous silica particles. This process exploits the concentration of evaporating droplets to induce the organization of various amphiphilic molecules, effectively partitioning the silica precursor (TEOS) to the hydrophilic regions of the structure. Promotion of silica condensation, followed by removal of the surfactant, provides ordered spherical mesoporous particles. Using the VOAG we have produced highly monodisperse particles in the 5 to 10 μm diameter range. The cationic surfactant CTAB typically leads to hexagonal mesostructure with mean pore size of about 2 nm and specific surface area around 900 m2/g. We have also shown that the pore size in CTABtemplated particles can be increased to 3.8 nm by incorporating trimethylbenzene as a swelling agent. The TMB prefentially locates inside and swells the hydrophobic regions of the surfactant mesostructure. Pore size can also be varied by the choice of amphiphile. Hexagonally ordered particles have been produced using the nonionic surfactant Brij-58 and block copolymer F127. These powders possessed mean pore size 2.8 nm and 6.9 nm, respectively. The uptake of alkyl pyridinium chloride molecules have recently been measured, revealing an uptake capacity that is explained by surface adsorption (as opposed to simple pore infiltration). Kinetics of the uptake process are still be analyzed.
Novel Structure of Fullerenes and Endohedral Fullerenes
Authors: Wang Chun-Ru , Bai Chun-Li , Shinohara Hisanori 
Published: June 2019

AbstractBy using Krätschmer-Huffman synthesis and HPLC separation method we have isolated a series of novel fullerenes and endohedral fullerenes. Various spectroscopic techniques, e.g., MS, NMR, UV-vis-NIR, TEM, X-ray diffraction spectrometry etc., were adopted to characterize the isolated fullerenes. Several fullerenes were revealed to hold novel structures and electronic properties. For examples, C80(D5d) was isolated and characterized to have an ellipsoidal structure which is in fact one of the shortest SW-nanotubes; The isolation of Sc2@C66 breaks the well-known isolated-pentagon-rule (IPR) for the first time, which shows that the unconventional fullerenes may be dramatically stabilized through encaging metal atoms; Sc2C2@C84 is a novel molecular endohedral fullerene in which the Sc2C2 cluster rotates rapidly along the main C2 axis of C84(D2d). This fullerene is predicted to be a molecular magnet and may be used as nano-switcher in electronics.
Electrostatic Self-assembly of Metal and Semiconductor Nanoparticles in Polyelectrolytes: Assembly Dynamics, and Electrochemical Behavior
Authors: Markarian Mariezabel , Jaber Jad , Xin Yan , Ghannoum Sara , Halaoui Lara I. 
Published: June 2019

AbstractThe electrostatic self-assembly of hetero-nanostructured multilayers of metal and semiconductor nanoparticles in polyelectrolytes, the self-assembly dynamics, and electrochemistry at the assembled films is reported. Polyacrylate-capped Pt (<d>=2.5 ± 0.6 nm) and Q-CdS nanoparticles (<d>=3.6 ± 0.5 nm) were assembled in poly(diallyldimethylammonium chloride). The nanoparticle assembly dynamics is shown to be a function of the nanoparticle solution ionic strength and its composition. Electrochemical studies at Pt nanoparticles in PDDA reveal that charge hopping is feasible through the nanocomposite film, and that the catalytic activity of the nanoparticles is retained in the assembled structures.
Synthesis, Characterization, and Applications of Organic-Inorganic Hybrid Mesoporous Silica Prepared by Microwave Heating
Authors: Chung Jinseong , Whaseung Ahn Dongjun-Kim , Ahn Whaseung , Cheong Wonjo 
Published: June 2019

AbstractOrganic-inorganic hybrid mesoporous materials containing homogeneously distributed ethane group in silica framework were prepared using 1,2 bis(trimethoxysilyl) ethane (BTME) as a precursor and alkyltrimethylammonium chloride/bromide surfactant as a template. Characterization of the materials was performed using XRD, TEM/SEM, 29Si– / 13C– NMR, and N2-adsorption. Hydrothermal synthesis assisted by microwave heating produced a 1-3 micronsized hybrid material with spherical morphology in substantially reduced time. Bifunctional materials containing BTME and either aminopropyl- or mercaptopropy- group within the same silica framework were also prepared with or without the presence of a swelling agent, mesitylene. Mn-salen complex tethering on the hybrid material produced a catalyst with a somewhat enhanced performance in cyclohexene etherification using TBHP as an oxidant. Testing of the hybrid material as a reverse phase HPLC column material after C18 surface-functionalization demonstrated a promising result, which warrants further optimization of synthesis parameters.
Ordered Mesoporous Silica Films Synthesized from Vapor Phase
Authors: Tanaka Shunsuke , Nishiyama Norikazu , Egashira Yasuyuki , Oku Yoshiaki , Ueyama Korekazu 
Published: June 2019

AbstractA novel synthesis route for mesostructured silica films is reported. Nano-phase transition from lamellar phase of surfactant to hexagonal phase of silica-surfactant nanocomposite was found under vapor infiltration. Vapor infiltration was performed using HCl as catalyst source and tetraethoxysilane (TEOS) as framework source. Highly ordered mesostructured silica films are obtained using alkyltrimethylammonium bromide CnTAB (the carbon number in the alkyl chain; n = 8, 10, 12, 14, 16, 18) as templating agent. The d values of the mesostructured silica films increase with increasing the length of the alkyl chain and are controllable by the synthetic temperature. The vapor infiltration synthesis is a simpler process compared to conventional sol-gel techniques and attractive for mass production of a variety of organic-inorganic composite materials and inorganic porous materials. This novel synthetic method provides opportunities for the creation of new materials technologies.
Continuous Flow Hyper-Polarized 129Xe-Mas Nmr Studies of Microporous Materials.
Authors: Nossov Andrei , Guenneau Flavien , Springuel-Huet Marie-Anne , Montouillout Valérie , Cognec Jean-Pierre , Knott Benno , Engelke Frank , Gédéon Antoine , Fernandez Christian 
Published: June 2019

Summary:A Magic Angle Spinning (MAS) NMR probe has been designed allowing the in-situ measurements of NMR spectra of working catalyst. The probe was built following the original design of M. Hunger [Hunger, 1995 #2]. It allows the magic angle spinning of powder samples up to 3.5 kHz, under gas flowing conditions, and at temperatures up to 573K.
Formation Study of Nanocomposite Thin Films of Ferrite Dispersed in a Silica Matrix Prepared by sol-Gel Process
Authors: D. S. Mohallem Nelcy , Seara Luciana M. 
Published: June 2019

AbstractMagnetic nanocomposite thin films formed by cobalt ferrite dispersed in silica matrix were prepared by sol-gel process using tetraethylorthosilicate (TEOS) as a precursor of silica, and metallic nitrates as precursors of the ferrite. The films were prepared with 5–50 wt. % ferrite contents and deposited on substrate using the dip-coating process. The films obtained were adherent, transparent, homogeneous and free of microcracks, with thickness between 30 and 500 nm. The films obtained presented crystalline CoFe2O4 phases dispersed in SiO2 amorphous matrix and saturation magnetization of approximately 9 emu/g considering the composite mass and 30 emu/g considering the ferrite mass.
Periodic Mesoporous SiCO Glasses with Cubic Symmetry Stable at 1000°C
Authors: Blum Raphaël , Goletto Valérie , Toury Bérangére , Babonneau Florence 
Published: June 2019

AbstractA periodic mesoporous organosilica (PMO) with cubic Pm3n structure has been prepared from bis(trimethoxysilyl)ethane and cetytriethylammonium chloride. The sample has been heat treated under argon up to 1000°C, and the pyrolysis intermediates were analysed by X-ray diffraction using synchrotron radiation, multinuclear solid state NMR (29Si, 13C and 1H) and N2 adsorption-desorption experiments. The cubic Pm3n structure is retained after pyrolysis at 1000°C. The sample is a SiCO glass with mixed SiCxO4-x units (x = 0, 1, 2) and a very large surface area of 730 m2/g.
Micron to Sub-Micron Sized Highly Ordered Mesoporous Silica Particles Prepared Using a High Energy Ball Milling Process
Authors: Hampsey J. Eric , De Castro Claudio L. , McCaughey Byron F. , Wang Donghai , Mitchell Brian S. , Lu Yunfeng 
Published: June 2019

AbstractHighly ordered mesoporous silica particles with sizes in the micron to sub-micron range are of great interest due to their applications as catalysts and filler materials. Currently, mesoporous silica particles are synthesized using large amounts of solvent, which is impractical for large scale-up in industry. This paper reports on a high-energy ball milling process that has been employed to create micron to sub-micron sized mesoporous silica particles starting from a silica xerogel prepared by a surfactant self-assembly sol-gel process. We have studied the effect of parameters such as milling media (e.g., zirconia, stainless steel, and steel centered nylon balls), milling time, the presence of surfactants during milling, particle size, and pore structure. Results from transmission electron microscopy (TEM), scanning electron microscopy (SEM), Xray diffraction (XRD), and nitrogen adsorption demonstrate the feasibility of producing large quantities of mesostructured particles by a simple milling process.
Synthesis of Phenol/Furfural Polymer Nanotubes
Authors: Uota Masafumi , Fujikawa Daisuke , Mohri Shinji , Kuroki Masako , Kaikake Katsuya , Yada Mitsunori , Machida Masato , Kijima Tsuyoshi 
Published: June 2019

AbstractThe first synthesis of phenol-furfural polymer nanotubes of 2–3nm hollow diameter is demonstrated as well as those with a hexagonal mesostructure. These nanopolymers were obtained by the templating method using a two-step reaction. At the first step, phenol and furfural were moderately reacted into cooligomers in the presence of NaOH. The resulting cooligomeric species were fully anionized and then reacted with additional phenol and alkyl trimetyl ammonium bromide at 40-80°C. The major phase for the 80°C product obtained at low concentration of surfactant was identified as nanotubular polymers of 1.9-3 nm inside and 6 nm outside diameters depending on the chain length of surfactant. In contrast, hexagonal mesostructured polymers characterized by a definite XRD peak occurred preferentially in the reaction using high surfactant-concentrations.
Silver-Polyimide Nanocomposite Membranes: Self-Generated Highly Reflective Flexible Mirrored Surfaces
Authors: Southward R. E. , Pevzner M. , Thompson D.W. 
Published: June 2019

AbstractThe synthesis of reflective silvered polyimide films by a single-stage auto-metallization process entailing the (hexafluoroacetylacetonato)silver(I) complex dissolved in solutions of poly(amic acid)s and polyimides formed from 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropanedianhydride (6FDA) and 2,2-bis(4-(4-aminophenoxy)hexafluoropropane (4-BDAF) is described. Heating cast silver(I)-poly(amic acid)/polyimide films effects silver(I) reduction and nanoaggregation giving reflective films for Ag concentrations from 6-10 wt %. A6% silver film gives specular reflectivies greater than 80%. Films prepared from the soluble fully imidized form of 6FDA/4-BDAF were less reflective.
Synthesis of Smart Mesoporous Materials
Authors: Rao G.V.Rama , Fu Qiang , Ista Linnea K. , Xu Huifang , Balamurugan S. , Sklar Larry A. , Ward Timothy L. , López Gabriel P. 
Published: June 2019

AbstractThis study details development of hybrid mesoporous materials in which molecular transport through mesopores can be precisely controlled and reversibly modulated. Mesoporous silica materials formed by surfactant templating were modified by surface initiated atom transfer radical polymerization of poly(N-isopropyl acrylamide) (PNIPAAm) a stimuli responsive polymer (SRP) within the porous network. Thermo gravimetric analysis and FTIR spectroscopy were used to confirm the presence of PNIPAAm on the silica surface. Nitrogen porosimetry, transmission electron microscopy and X-ray diffraction analyses confirmed that polymerization occurred uniformly within the porous network. Uptake and release of fluorescent dyes from the particles was monitored by spectrofluorimetry and scanning laser confocal microscopy. Results suggest that the presence of PNIPAAm, a SRP, in the porous network can be used to modulate the transport of aqueous solutes. At low temperature, (e.g., room temperature) the PNIPAAm is hydrated and extended and inhibits transport of analytes; at higher temperatures (e.g., 50°C) it is hydrophobic and is collapsed within the pore network, thus allowing solute diffusion into or out of the mesoporous silica. The transition form hydrophilic to hydrophobic state on polymer grafted mesoporous membranes was determined by contact angle measurements. This work has implications for the development of materials for the selective control of transport of molecular solutes in a variety of applications.
Dynamics and Rheology of GlassyMicellar Block Polyelectrolytes
Authors: Grandjean Julien , Mourchid Ahmed 
Published: June 2019

AbstractMicellar solutions of polystyrene-poly(acrylic acid) block copolymers are studied in the jammed regime. Increasing attraction between soft spheres, both the rheology and dynamic light scattering show a re-entrant liquid to glass transition. The dynamics was also investigated at an attraction strength above the re-entrant transition line. Increasing concentration of sticky soft spheres in this region, the particle dynamics shows a remarkable extended logarithmic decay. The theoretical predictions of mode coupling theory agree well with our results.