Search results for "substrate"
showing 10 items of 1018 documents
New Reusable Solid Biosensor with Covalent Immobilization of the Horseradish Peroxidase Enzyme: In Situ Liberation Studies of Hydrogen Peroxide by Po…
2019
Herein, we reported a chemiluminescent biosensor based on the covalent immobilization of the horseradish peroxidase (HRP) enzyme on a polydimethylsiloxane (PDMS) support to quantify in situ hydrogen peroxide (H2O2). The chemiluminescent reaction based on the use of luminol as an oxidizable substrate, with HRP as the catalyst, has been used in order to quantify H2O2 as the oxidizing agent. The performance of the proposed biosensor has been demonstrated to determine H2O2 liberated by cells in a culture medium and for evaluating the delivery of H2O2 from denture cleaner tablets, as examples of application. For both analyses, the results indicated that the biosensor is cost-effective, sensitive…
Zinc removal in anaerobic sulphate-reducing liquid substrate process
2002
Abstract Zinc and sulphate removal from synthetic wastewater was investigated by using four laboratory parallel upflow-mode reactors (referred as R1 to R4; R1 contained carriers to retain biomass, whereas R2–R4 were operated as suspended reactors). All reactors were inoculated with anaerobically digested cow manure. R1 and R2 were first fed with glucose- and sulphate-containing feed for 48 days after which all four reactors were fed with wastewater containing 50 mg l−1 of zinc in R1–R3 and 200 mg l−1 in R4 and operated for 96 days. In all reactors, hydraulic retention time, organic loading rate, and sulphate load were 5–6 d, 0.2–0.4 kg COD m−3 d−1 and 3.3–3.8 g SO4 l−1 d−1, respectively, wh…
A new interpretation of the 22-tricosenoic acid Langmuir-Blodgett structures identified as triclinic by Rheeds
1990
Abstract One of the original structural studies on Langmuir-Blodgett (LB) multilayers of 22-tricosenoic acid using the technique of reflection high-energy electron diffraction was performed by Peterson and Russell (1984, Phil. Mag. A, 49, 463). In their paper, four distinct structural arrangements of the long-chain fatty acid were identified, where the arrangement adopted by a particular sample was found to depend on the substrate and deposition conditions. The identification of the C2 H4 subcells in each of these arrangements was made on the basis of a number of assumptions, some of which have subsequently been shown to be erroneous. In particular, the identification of a triclinic subcell…
X‐ray characterization of CdO thin films grown on a ‐, c ‐, r ‐ and m ‐plane sapphire by metalorganic vapour phase‐epitaxy
2005
CdO thin films have been grown on a-plane (110), c-plane (0001), r-plane (012) and m-plane (100) sapphire substrates by metalorganic vapour-phase epitaxy (MOVPE). The effects of different substrate orientations on the structural properties of the films have been analyzed by means of X-ray diffraction, including θ-2θ scans, pole figures and rocking curves. (111), (001) and (110) orientations are found on a-, r-, and m-sapphire respectively, while films deposited on c-plane exhibit an orientation in which no low-index crystal plane is parallel to the sample surface. The recorded pole figures have allowed determining the epitaxial relationships between films and substrates, as well as the pres…
Gilbert damping of CoFe-alloys
2019
We report structural, magnetic and dynamic properties of polycrystalline Coalt;subagt;xalt;/subagt;Fealt;subagt;1-xalt;/subagt;-alloy films on Sapphire, Silicon and MgO substrates across the full composition range, by using a Vector Network Analyser ferromagnetic resonance measurement technique (VNA-FMR), Superconducting Quantum Interference Device magnetometry (SQUID) and X-Ray Diffraction (XRD). In the approximate vicinity of 28% Co, we observe a minimum of the damping parameter, associated with a reduction in the density of states to a minimum value at the Fermi energy level. For films on all substrates, we find magnetic damping of the order of 4-5⋅10alt;supagt;-3alt;/supagt;, showing th…
Shaping graphene with optical forging: from a single blister to complex 3D structures
2020
Properties of graphene, such as electrical conduction and rigidity can be tuned by introducing local strain or defects into its lattice. We used optical forging, a direct laser writing method, under an inert gas atmosphere, to produce complex 3D patterns of single layer graphene. We observed bulging of graphene out of the plane due to defect induced lattice expansion. By applying low peak fluences, we obtained a 3D-shaped graphene surface without either ablating it or deforming the underlying Si/SiO2 substrate. We used micromachining theory to estimate the single-pulse modification threshold fluence of graphene, which was 8.3 mJ cm−2, being an order of magnitude lower than the threshold for…
Which tool to distinguish transient alumina from alpha alumina in thermally grown alumina scales?
2005
International audience; Alumina scales constitute excellent protective barriers when they form on alumina-forming steels. If they keep tightly adherent to the underlying substrate, they isolate it from the surrounding aggressive atmosphere at high temperature. The protectiveness of the alumina scale is highly dependant upon its growth mechanism. The nucleation and transformation of transient alumina (mainly g-Al2O3 and y-Al2O3) is known to play an important role on alumina scale formation. It is therefore fundamental to characterise these transient alumina especially during the early stages of the oxidation process. The morphology of the transient alumina was observed by scanning electron m…
An electron diffraction study of deposited docosanoic acid monolayers
1991
Docosanoic acid monolayers deposited on thin polymer films under different water surface conditions have been investigated using transmission electron diffraction at normal and tilted incidence. Diffraction patterns obtained from the L2 and L2' phase are quite similar, but distinctly different to samples coated from the CS phase. The former were consistent with molecules perpendicular to the substrate, arranged in a texture of grains with unusual orthorhombic packing. There is evidence for a phase transition from a liquid crystalline phase on the water surface.
Effect of Substituents on the Molecular Shapes of π-Basic Macrotricyclic Receptors
2010
Molecular recognition between receptor and substrate is optimized when these compounds show complementary shapes, sizes, and interacting moieties. A family of C3v-symmetric macrotricycles 1–4 is presented that incorporate resorcinol- and mesitylene-derived “walls” and “cap”, respectively. These compounds feature, in principle, a tetrahedral π-basic cavity. This paper reports the effect of substituents in the “walls” and the “cap” on the shapes of the macrotricycles in solution (1H NMR), the solid state (X-ray diffraction), and gas phase (calculations). Substitution of the lower position of the “walls” by Br (in 3) or MeS (in 4) has the same effect as ethyl substitution of the “cap” (in 2), …
Dip Pen Lithography of oligonucleotides on flexible substrates for point-of-care malaria disease testing
2015
The first step for prevention and treatment of diseases is the accurate diagnosis. However, proper diagnostic technologies are not available in developing countries due to the lack of reliable electrical power, refrigeration and trained personnel. For this reason, there is an urgent need of low cost, rapid assays not requiring any external support. By coupling such technologies to communication infrastructures, healthcare in areas without access to medical personnel would be possible. “Paper” like substrates are ideal for fabricating such devices since they are cheap, easy to degradate after use and compatible with most of existing printing technologies [1]. We had previously shown the poss…