Glass Support Research Articles

Interactions between Zn2+ or ZnO with TiO2 to produce an efficient photocatalytic, superhydrophilic and aesthetic glass

Abstract Zinc was coupled with titanium dioxide using different methods. SiO2 and Zn-SiO2 doped TiO2 films, on the one hand, and Zn doped TiO2 on the other hand, have been produced using controlled sol-gel processes by alcoholic, cogelation and aqueous ways. From these syntheses, films were deposited on soda lime glass. These samples were compared to ZnO samples but also to bilayer samples constituting one layer of TiO2 and one layer of ZnO. The physico-chemical properties of the films were characterized by grazing-incidence X-ray diffraction, profilometry and UV–vis absorption analyses. The photocatalytic activity has been evaluated from the degradation of methylene blue under UV-A light, from the degradation of p-nitrophenol under visible light and from the degradation of H2O2 under halogen light (UV-A + visible light). Superhydrophilicity was evaluated from contact angle measurement after UV exposition and also from hysteresis effects. Finally, a haze measurement was performed to evaluate the impact of the coating on the aesthetic property of the coated glass. Aqueous films have better photocatalytic activity and superhydrophilicity than samples from alcoholic synthesis. The crystallization of the sample appears to be one key factor: alcoholic films required calcination to ensure the crystallization of TiO2, but the alkali migration from the glass support prevents this crystallization, while aqueous synthesis promotes crystallized particles at low temperatures without alkali interference. It appears that the relative activity from one sample to another depends on the nature of the illumination and on the nature of the molecule to be degraded. Nevertheless, the sample with ZnO layer deposited on first TiO2 layer (ZnO 500 Alc/TiO2 100 AQ) composite is found to be the best sample, maintaining a high hydrophilicity similar to TiO2 and a good activity.

Gynecological brachytherapy with Elekta microSelectron V3 afterloading system

Abstract Objective: For commissioning of source path mo-dels for ring tubes of Nucletron (now Elekta) CT/MR ring applicators, a method was established using a source position simulator (SPS) and a CT scanner. Methods: An acrylic glass support for ring tubes was constructed serving as defined coordinate system. With SPS, 40 positions were set in the ring in steps of 2.5mm from proximal to distal direction. In each position a CT-series was taken with ring plane inside scan plane using a GE Optima 580 scanner (slice width 0.625mm). Evaluation was done in multiplanar recon-struction mode under display settings revealing dummy source shape. With a 3D-cursor dwell position coordinate (center of Ir-192 core) was determined. Measurements were validated by film autoradiography in selected positions. Four rings were investigated: 60° Φ26, 45° Φ26, 60° Φ30, and 45° Φ30 with figures denoting angle between ring plane and stem and ring diameter in mm. Results: The method is feasible to reconstruct source dwell positions with an overall accuracy of ±0.3mm. Detected coordinates are consistent and in excel-lent agreement with those obtained by autoradiography. Comparison with Elekta’s source path models, however, re-vealed mean deviations of up to 3.5mm. Discussion: It is advisable to measure individual source paths and have them added to the data base of the treatment planning system.

The Effect of Globular Protein from Aleurone Cells of Barley on Stearic Acid Monolayers

Aleurone cells of barley accumulate the major storage globular protein, which is deposited in different patterns, such as protein and lipid self-assemblies. To better understand the complexity of storage self-assemblies, a fatty acid is chosen as a lipid model, namely stearic acid, SA, because of its high stability in monolayers at the air/aqueous solutions interface. The effect of aleurone cell protein, AC protein, on the phase behavior and surface structure of SA monolayers at the air/water interface has been studied by a combined Langmuir and Langmuir-Blodgett (LB) technique and by atomic force microscopy (AFM) investigation. The AC protein and SA monolayers were transferred on glass support, at several controlled surface pressures, characteristic for both the condensed liquid and solid phase of pure SA monolayers. The results indicate that globular particles of AC protein adsorb on and penetrate into and specifically interact with SA monolayers stabilizing the lipid/protein interface by achieving highly ordered self-assemblies, which may also occur within aleurone layers. These structures might play an important role both in aleurone cell development and in seedling growth.

Protocol for the Solid-phase Synthesis of Oligomers of RNA Containing a 2'-<em>O</em>-thiophenylmethyl Modification and Characterization via Circular Dichroism

Solid-phase synthesis has been used to obtain canonical and modified polymers of nucleic acids, specifically of DNA or RNA, which has made it a popular methodology for applications in various fields and for different research purposes. The procedure described herein focuses on the synthesis, purification, and characterization of dodecamers of RNA 5'-[CUA CGG AAU CAU]-3' containing zero, one, or two modifications located at the C2'-O-position. The probes are based on 2-thiophenylmethyl groups, incorporated into RNA nucleotides via standard organic synthesis and introduced into the corresponding oligonucleotides via their respective phosphoramidites. This report makes use of phosphoramidite chemistry via the four canonical nucleobases (Uridine (U), Cytosine (C), Guanosine (G), Adenosine (A)), as well as 2-thiophenylmethyl functionalized nucleotides modified at the 2'-O-position; however, the methodology is amenable for a large variety of modifications that have been developed over the years. The oligonucleotides were synthesized on a controlled-pore glass (CPG) support followed by cleavage from the resin and deprotection under standard conditions, i.e., a mixture of ammonia and methylamine (AMA) followed by hydrogen fluoride/triethylamine/N-methylpyrrolidinone. The corresponding oligonucleotides were purified via polyacrylamide electrophoresis (20% denaturing) followed by elution, desalting, and isolation via reversed-phase chromatography (Sep-pak, C18-column). Quantification and structural parameters were assessed via ultraviolet-visible (UV-vis) and circular dichroism (CD) photometric analysis, respectively. This report aims to serve as a resource and guide for beginner and expert researchers interested in embarking in this field. It is expected to serve as a work-in-progress as new technologies and methodologies are developed. The description of the methodologies and techniques within this document correspond to a DNA/RNA synthesizer (refurbished and purchased in 2013) that uses phosphoramidite chemistry.

Protocol for the Solid-phase Synthesis of Oligomers of RNA Containing a 2'-O-thiophenylmethyl Modification and Characterization via Circular Dichroism.

Solid-phase synthesis has been used to obtain canonical and modified polymers of nucleic acids, specifically of DNA or RNA, which has made it a popular methodology for applications in various fields and for different research purposes. The procedure described herein focuses on the synthesis, purification, and characterization of dodecamers of RNA 5'-[CUA CGG AAU CAU]-3' containing zero, one, or two modifications located at the C2'-O-position. The probes are based on 2-thiophenylmethyl groups, incorporated into RNA nucleotides via standard organic synthesis and introduced into the corresponding oligonucleotides via their respective phosphoramidites. This report makes use of phosphoramidite chemistry via the four canonical nucleobases (Uridine (U), Cytosine (C), Guanosine (G), Adenosine (A)), as well as 2-thiophenylmethyl functionalized nucleotides modified at the 2'-O-position; however, the methodology is amenable for a large variety of modifications that have been developed over the years. The oligonucleotides were synthesized on a controlled-pore glass (CPG) support followed by cleavage from the resin and deprotection under standard conditions, i.e., a mixture of ammonia and methylamine (AMA) followed by hydrogen fluoride/triethylamine/N-methylpyrrolidinone. The corresponding oligonucleotides were purified via polyacrylamide electrophoresis (20% denaturing) followed by elution, desalting, and isolation via reversed-phase chromatography (Sep-pak, C18-column). Quantification and structural parameters were assessed via ultraviolet-visible (UV-vis) and circular dichroism (CD) photometric analysis, respectively. This report aims to serve as a resource and guide for beginner and expert researchers interested in embarking in this field. It is expected to serve as a work-in-progress as new technologies and methodologies are developed. The description of the methodologies and techniques within this document correspond to a DNA/RNA synthesizer (refurbished and purchased in 2013) that uses phosphoramidite chemistry.

Aptamer based bare eye detection of kanamycin by using a liquid crystal film on a glass support

The authors describe an aptamer-based liquid crystal (LC) assay for kanamycin (KNM) that displays visible signal changes. The KNM aptamer was immobilized, along with the N,N-dimethyl-N-(3-(trimethoxysilyl)propyl)-1-octadecanaminiuchloride (DMOAP) on a glass slide, and this results in a homeotropic orientation of the LCs film. In the presence of KNM, its interaction with the aptamers will result in the formation of G-quadruplexes. These will destroy the orientated arrangement of the LCs on the surface to result in a color change from pink to green that can be visually observed by using crossed polarizers. The method possesses high specificity and the detection limit is as low as 1 nM. Unlike current laboratory-based KNM assays, this method does not require instrumental read-out which is highly beneficial in terms of on-site food analysis.

Facile low temperature immobilization of N-doped TiO2 prepared by sol–gel method

In this study, simplified and low temperature sol–gel preparation method was investigated at different concentrations of tetraethylorthosilicate for better adhesive strength to glass support and photocatalytic decolorization activities on methylene blue. The physical and chemical characteristics of pure N-doped TiO2 and property changes due to addition of tetraethylorthosilicate were characterized by X-ray photoelectron spectroscopy, X-ray diffraction, nitrogen adsorption–desorption isotherms, UV–Vis spectra, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, and high-resolution transmission electron microscopy. The results showed that the addition of tetraethylorthosilicate significantly improved the Brunauer–Emmett–Teller surface area, the amount of hydroxyl groups and adhesive strength of the catalyst. However, the photoactivity of the catalyst was suppressed at the higher concentrations of tetraethylorthosilicate (20 and 30%). Based on these results, 5% tetraethylorthosilicate was found to be an optimum value for successful immobilization of N-doped TiO2 on the glass beads. Only 6% loss in its photoactivity was observed at the 5th cycle test indicating that deterioration of catalytic activity was very low.

Enhanced photoelectrochemical CO2-reduction system based on mixed Cu2O – nonstoichiometric TiO2 photocathode

Photoelectrochemical reduction of CO2 is explored here with respect to the possible production of simple organic fuels. While the photoelectrochemical system is based on p-type Cu2O semiconductor, special attention has been paid to its stabilization, intentional modification and fabrication, as well as to optimization of experimental conditions permitting control and diversification of the CO2 reduction products. Utilization of the mixed oxides photoelectrochemical system consisting of the electrodeposited, onto transparent conductive oxide (TCO) coated glass support, Cu2O catalyst and next coupled to non-stoichiometric TiO2, acting as a charge transfer enhancing layer. Such a heterojunction allows, from one side, increase density of charge carries in the conduction band of the photocathode and, on the other side, improve conductivity of the whole system. Moreover, the outer-most over-layer of Nafion is expected to facilitate attraction of CO2 (dissolved in the sodium sulfate electrolyte) at the photoelectrochemically active mixed-metal-oxides interface. Consequently, the overall photoelectrochemical efficiency is improved, and the cathodic photocurrent (related to the CO2-reduction) of ca. 1.2mA cm−2 (at 0.1V vs. RHE). The reported hierarchical (layered mixed-oxide) system consisting of copper(I) oxide and titania over-layer (covered with the Nafion outer-most film) exhibits remarkable stability with time.

Ozone-UV-catalysis based advanced oxidation process for wastewater treatment.

A bench-scale advanced oxidation (AO) reactor was investigated for the degradation of six pollutants (2-naphthol, phenol, oxalic acid, phthalate, methylene blue, and D-glucose) in a model wastewater at with the aim to test opportunities for the further upscale to industrial applications. Six experimental conditions were designed to completely examine the experimental reactor, including photolysis, photocatalysis, ozonation, photolytic ozonation, catalytic ozonation, and photocatalytic ozonation. The stationary catalyst construction was made from commercially available TiO2 nanopowder by mounting it on a glass support and subsequently characterized for morphology (X-ray diffraction analysis and scanning electron microscopy) as well as durability. The ozone was generated in a dielectrical barrier discharge reactor using air as a source of oxygen. The degradation efficiency was estimated by the decrease in total organic carbon (TOC) concentration as well as toxicity using Daphnia magna, and degradation by-products by ultra-performance liquid chromatography-mass spectrometry. The photocatalytic ozonation was the most effective for the treatment of all model wastewater. The photocatalytic ozonation was most effective against ozonation and photolytic ozonation at tested pH values. A complete toxicity loss was obtained after the treatment using photocatalytic ozonation. The possible degradation pathway of the phthalate by oxidation was suggested based on aromatic ring opening reactions. The catalyst used at this experiment confirmed as a durable for continuous use with almost no loss of activity over time. The design of the reactor was found to be very effective for water treatment using photocatalytic ozonation. Such design has a high potential and can be further upscaled to industrial applications due to the simplicity and versatility of manufacturing and maintenance.

A High-Throughput Process for the Solid-Phase Purification of Synthetic DNA Sequences.

An efficient process for the purification of synthetic phosphorothioate and native DNA sequences is presented. The process is based on the use of an aminopropylated silica gel support functionalized with aminooxyalkyl functions to enable capture of DNA sequences through an oximation reaction with the keto function of a linker conjugated to the 5'-terminus of DNA sequences. Deoxyribonucleoside phosphoramidites carrying this linker, as a 5'-hydroxyl protecting group, have been synthesized for incorporation into DNA sequences during the last coupling step of a standard solid-phase synthesis protocol executed on a controlled pore glass (CPG) support. Solid-phase capture of the nucleobase- and phosphate-deprotected DNA sequences released from the CPG support is demonstrated to proceed near quantitatively. Shorter than full-length DNA sequences are first washed away from the capture support; the solid-phase purified DNA sequences are then released from this support upon reaction with tetra-n-butylammonium fluoride in dry dimethylsulfoxide (DMSO) and precipitated in tetrahydrofuran (THF). The purity of solid-phase-purified DNA sequences exceeds 98%. The simulated high-throughput and scalability features of the solid-phase purification process are demonstrated without sacrificing purity of the DNA sequences. © 2017 by John Wiley & Sons, Inc.

A Simple Post-Polymerization Modification Method for Controlling Side-Chain Information in Digital Polymers.

A three-step post-polymerization modification method was developed for the design of digitally encoded poly(phosphodiester)s with controllable side groups. Sequence-defined precursors were synthesized, either manually on polystyrene resins or automatically on controlled pore glass supports, using two phosphoramidite monomers containing either terminal alkynes or triisopropylsilyl (TIPS) protected alkyne side groups. Afterwards, these polymers were modified by stepwise copper-catalyzed azide-alkyne cycloaddition (CuAAC). The terminal alkynes were first reacted with a model azide compound, and after removal of the TIPS groups, the remaining alkynes were reacted with another organic azide. This simple method allows for quantitative side-chain modification, thus opening up interesting avenues for the preparation of a wide variety of digital polymers.

Surface properties of ion-inducted whey protein gels deposited on cold plasma treated support

So far no studies have been undertaken on the influence of plasma processing of different solid surfaces on the properties of subsequently formed protein coat. Calcium chloride, magnesium chloride or iron (II) chloride inducing whey protein isolate gels were obtained on glass support previously treated with the plasma at the electric voltage 160 V per 1 min. Dynamic oscillatory and ultrasound viscosity measurements, scanning electron microscopy imaging, surface roughness and contact angles measurements have been performed. Apparent surface free energy was determined using the two approaches: van Oss, Good and Chaudchury (LWAB) and contact angle hysteresis (CAH). Gels surface roughness increased with the increasing of ions concentration. Both approaches used for determination of apparent surface free energy give comparable results. When the air plasma was applied for the support activation, polar groups deposited on the surface had a greater effect on the surface wettability than roughness. Plasma treatment of glass support caused the increase of hydrophobic properties of deposited layers. Wettability properties were affected by the electron donor parameter of energy whose value increased for the samples obtained on the plasma activated supports especially the air treated ones. Plasma treatment of glass plates might have an effect on food processing, production efficiency, microbiological aspects and cleaning process of the gels deposited on their surfaces.

Wettability and thermal analysis of hydrophobic poly(methyl methacrylate)/silica nanocomposites

Hydrophobic poly(methyl methacrylate)/silica layers on the glass support activated with plasma were obtained. Wettability was investigated from the contact angle measurements and surface free energ...

High aspect ratio silicon nanowires control fibroblast adhesion and cytoskeleton organization

Cell–cell and cell–matrix interactions are essential to the survival and proliferation of most cells, and are responsible for triggering a wide range of biochemical pathways. More recently, the biomechanical role of those interactions was highlighted, showing, for instance, that adhesion forces are essential for cytoskeleton organization. Silicon nanowires (Si NWs) with their small size, high aspect ratio and anisotropic mechanical response represent a useful model to investigate the forces involved in the adhesion processes and their role in cellular development. In this work we explored and quantified, by single cell force spectroscopy (SCFS), the interaction of mouse embryonic fibroblasts with a flexible forest of Si NWs. We observed that the cell adhesion forces are comparable to those found on collagen and bare glass coverslip, analogously the membrane tether extraction forces are similar to that on collagen but stronger than that on bare flat glass. Cell survival did not depend significantly on the substrate, although a reduced proliferation after 36 h was observed. On the contrary both cell morphology and cytoskeleton organization revealed striking differences. The cell morphology on Si-NW was characterized by a large number of filopodia and a significant decrease of the cell mobility. The cytoskeleton organization was characterized by the absence of actin fibers, which were instead dominant on collagen and flat glass support. Such findings suggest that the mechanical properties of disordered Si NWs, and in particular their strong asymmetry, play a major role in the adhesion, morphology and cytoskeleton organization processes. Indeed, while adhesion measurements by SCFS provide out-of-plane forces values consistent with those measured on conventional substrates, weaker in-plane forces hinder proper cytoskeleton organization and migration processes.

Synthesis of Hierarchical SnO2 Nanowire\u2013TiO2 Nanorod Brushes Anchored to Commercially Available FTO-coated Glass Substrates

Growth of single-crystal SnO2 nanowires using a fluorine-doped SnO2 (FTO) thin film as both the source and substrate is demonstrated for the first time at relatively low temperature (580 °C) which preserves the integrity of the underlying glass support and improves scalability to devices. Furthermore, a microwave hydrothermal process is shown to grow TiO2 nanorods on these nanowires to create a hierarchical nanoheterostructure that will lead to efficient photogenerated charge carrier separation and rapid transport of electrons to the substrate. This process simplifies nanowire growth by using commercially available and widely used FTO substrates without the need for an additional upstream Sn source and can be used as a high surface area host structure to many other hierarchical structures.

Photocatalytic activities of TiO2 layers immobilized on glass substrates by dip-coating technique toward the decolorization of methyl orange as a model organic pollutant

The aim of this article is to evaluate the photocatalytic activities of the immobilized catalyst layers of titanium dioxide for the decolorization of methyl orange aqueous solution (MO) as a model organic contaminant under UV irradiation. Three stable layers of TiO2 powder were coated on glass substrate by facile dip-coating technique. XRD analysis showed anatase crystalline structure of catalyst films. The films crystallinity increased with the layers number. SEM analysis showed porous TiO2 films. The multi-coating increased the coverage surface of glass support. The catalyst films showed well reproducibility and good adhesion to the support after tests. The effects of operating parameters and the number of catalyst layers on the MO decolorization were investigated. The kinetic study of the MO photodecolorization showed a pseudo-first-order reaction. The MO color removal by the use of three coated layers of catalyst in the optimum reactor was more effective and 5 times faster than that with the use of one coated layer of catalyst at normal conditions. The immobilized layers of TiO2 powder was found photocatalytic active for complete MO decolorization in the optimum reactor. The immobilized system may replace suspension mode and eliminate the costly separation process.

Modification and characterization of microwave assisted N doped TiO2 – a photodegradation study under suspension and immobilized system

A commercially available TiO2 (P25) was modified to produce nitrogen (N) doped TiO2 prepared by mixing TiO2 powder with various amounts of urea as N precursor using a microwave irradiation heating technique. X-ray photoelectron spectroscopy analysis showed that N chemically bonded with TiO2 produces Ti-N. The measured band gap energy (Eg) of the modified sample was ca. 2.9 eV as detected by UV-Vis/DRS. The optimum modified N doped TiO2 denoted as U3-800 prepared at 230 °C showed an active visible light photoactivity. This observation shows that microwave irradiation is able to form Ti-N at low temperature whereas this previously could not be achieved under conventional heating using a muffle furnace at the same temperature. U3-800 showed visible light active photodegradation for 30, 10 and 5 mg L−1 of reactive red 4, crystal violet and Janus green dyes, respectively, in less than 105 min to complete decolorization under suspension mode while no photocatalytic activity was observed under pristine TiO2 under the same conditions. Immobilization of a U3-800 sample was carried out using DSAT as a thin layer binder and the photoactivity of Immobilize/U3-800/DSAT is comparable with the suspension mode. Surprisingly, immobilized/U3-800 has a strong coating with glass support material and can be continuously used for 30 cycles without affecting photoactivity performance.

Thin film of Yttria stabilised zirconia on NiO using vacuum cold spraying process for solid oxide fuel cell

Yttria stabilised zirconia (YSZ) was fabricated on a glass and NiO-YSZ anode support substrate using the vacuum cold spraying (VCS) technique at room temperature. The field emission scanning electrode microscope (FESEM) analysis revealed a dense microstructure and several vertical cracks within 0.1 μm width of the YSZ film. The transmission electron microscopy (TEM) was used to analyse the grain size and it was found to be 20 nm which was finer size compared to the average particle size of the starting YSZ powder. The x-ray diffraction (XRD) analysis showed lacking of phase transformation during the VCS process. The YSZ film fabricated by VCS technique showed better gas tightness compared to that fabricated by atmospheric plasma spray process. The Young's modulus of the YSZ film was found to be 172 GPa.

Correlation of live-cell imaging with volume scanning electron microscopy.

Live-cell imaging is one of the most widely applied methods in live science. Here we describe two setups for live-cell imaging, which can easily be combined with volume SEM for correlative studies. The first procedure applies cell culture dishes with a gridded glass support, which can be used for any light microscopy modality. The second approach is a flow-chamber setup based on Ibidi μ-slides. Both live-cell imaging strategies can be followed up with serial blockface- or focused ion beam-scanning electron microscopy. Two types of resin embedding after heavy metal staining and dehydration are presented making best use of the particular advantages of each imaging modality: classical en-bloc embedding and thin-layer plastification. The latter can be used only for focused ion beam-scanning electron microscopy, but is advantageous for studying cell-interactions with specific substrates, or when the substrate cannot be removed. En-bloc embedding has diverse applications and can be applied for both described volume scanning electron microscopy techniques. Finally, strategies for relocating the cell of interest are discussed for both embedding approaches and in respect to the applied light and scanning electron microscopy methods.

Transparent titania-zirconia-silica thin films for self-cleaning and photocatalytic applications

Highly transparent thin films of TiO2-ZrO2-SiO2 composites on glass were prepared by sol-gel process, wherein different amounts of zirconia precursor were mixed with titania precursor solution (0–20mol% Zr with regard to Ti). For better adhesion of the films on glass supports, a silica binder was added to the mixture of alkoxides (27mol% Si vs. Ti). The prepared samples were characterized by various techniques to obtain information on their structural, optical and surface properties. The presence of anatase titania polymorph as the only crystalline phase was detected. Unexpectedly, the higher loading of Zr promoted the growth of anatase particles with progressive spherical shape and concomitant decrease of specific surface area, which adversely influenced the photocatalytic activity. Decrease of the photodegradation activity with increasing amount of Zr was evidenced by contact angle measurements of a fatty deposit, spectrofluorometrically using terephthalic acid probe and by EPR spectroscopy monitoring indirectly the non-persistent radicals generation. On the other hand, the higher content of Zr improved the mechanical stability of resulting thin films. An optimal Zr content around 10mol% appears to be a good compromise between photocatalytic activity and mechanical robustness of the films.