Layer-by-layer coating of alginate matrices with chitosan–alginate for the improved survival and targeted delivery of probiotic bacteria after oral administration

The oral administration of probiotic bacteria has shown potential in clinical trials for the alleviation of specific disorders of the gastrointestinal tract. However, cells must be alive in order to exert these benefits. The low pH of the stomach can greatly reduce the number of viable microorganisms that reach the intestine, thereby reducing the efficacy of the administration. Herein, a model probiotic, Bifidobacterium breve, has been encapsulated into an alginate matrix before coating in multilayers of alternating alginate and chitosan. The intention of this formulation was to improve the survival of B. breve during exposure to low pH and to target the delivery of the cells to the intestine. The material properties were first characterized before in vitro testing. Biacore™ experiments allowed for the polymer interactions to be confirmed; additionally, the stability of these multilayers to buffers simulating the pH of the gastrointestinal tract was demonstrated. Texture analysis was used to monitor changes in the gel strength during preparation, showing a weakening of the matrices during coating as a result of calcium ion sequestration. The build-up of multilayers was confirmed by confocal laser-scanning microscopy, which also showed the increase in the thickness of coat over time. During exposure to in vitro gastric conditions, an increase in viability from <3 log(CFU) per mL, seen in free cells, up to a maximum of 8.84 ± 0.17 log(CFU) per mL was noted in a 3-layer coated matrix. Multilayer-coated alginate matrices also showed a targeting of delivery to the intestine, with a gradual release of their loads over 240 min.

Capillary assay device with internal hydrophilic coating

The present invention provides assay devices having a unitary body with an exterior surface, the unitary body being substantially transparent to visible light and formed from a material having a refractive index in the range 1.26 to 1.40, the refractive index being measured at 20 °C with light of wavelength 589 nm, and wherein the unitary body is formed from a hydrophobic material, and at least two capillary bores extending internally along the unitary body, wherein at least a portion of the surface of each capillary bore includes a hydrophilic layer for retaining an assay reagent, and wherein the hydrophilic layer is also substantially transparent to visible light to allow optical interrogation of the capillary bores through the capillary wall. The present invention also provides assay systems including such assay devices, methods of performing an assay using such assay devices and method of method for manufacturing such assay devices.

Development of a new stir bar sorptive extraction coating and its application for the determination of six pesticides in sugarcane juice

In this article, a novel polydimethylsiloxane/activated carbon (PDMS-ACB) material is proposed as a new polymeric phase for stir bar sorptive extraction (SBSE). The PDMS-ACB stir bar, assembled using a simple Teflon (R)/glass capillary mold, demonstrated remarkable stability and resistance to organic solvents for more than 150 extractions. The SBSE bar has a diameter of 2.36 mm and a length of 2.2 cm and is prepared to contain 92 mu L of polymer coating. This new PDMS-ACB bar was evaluated for its ability to determine the quantity of pesticides in sugarcane juice samples by performing liquid desorption (LD) in 200 mu L of ethyl acetate and analyzing the solvent through gas chromatography coupled with mass spectrometry (GC-MS). A fractional factorial design was used to evaluate the main parameters involved in the extraction procedure. Then, a central composite design with a star configuration was used to optimize the significant extraction parameters. The method used demonstrated a limit of quantification (LOQ) of 0.5-40 mu g/L, depending on the analyte detected; the amount of recovery varied from 0.18 to 49.50%, and the intraday precision ranged from 0.072 to 8.40%. The method was used in the analysis of real sugarcane juice samples commercially available in local markets.

Photochromic wool fabrics from a hybrid silica coating

In this work, a photochromic wool fabric has been prepared by applying a photochromic-dye hybrid silica sol-gel onto the surface of fabric. The photochromic fabric was found to have a very quick optical response. Two types of silica were used as the matrix material, and the type of silica had a small effect only on the photochromic performance, the fabric washing fastness, and water contact angle, but affected the fabric handle property considerably. The silica from a precursor containing a long alkyl chain showed very little influence on the fabric handle and better photochromic performance than that containing a phenyl group.

Residual thermal stresses in a Fe3Al/Al2O3 gradient coating system

To combine the merits of both metals and ceramics into one material, many researchers have been studying the deposition of alumina coating using plasma spray on metal substrates. However, as the coatings are deposited at a high temperature, residual thermal stresses develop due to the mismatch of thermal expansion coefficients of the coating and substrate and these are responsible for the initiation and expansion of cracks, which induce the possible failure of the entire material. In this paper, the residual thermal-structural analysis of a Fe3Al/Al2O3 gradient coating on carbon steel substrate is performed using finite element modelling to simulate the plasma spray. The residual thermal stress fields are obtained and analyzed on the basis of temperature fields in gradient coatings during fabrication. The distribution of residual thermal stresses including radial, axial and shear stresses shows stress concentration at the interface between the coatings and substrate. The mismatch between steel substrate and composite coating is still the dominant factor for the residual stresses

Fibre coating composition

An abrasion-resistant, electrically conductive material comprising a natural fibre-containing substrate and an electrically conductive conjugated polymer coating thereon is disclosed. A process for preparing an abrasion-resistant, electrically conductive material is also disclosed. The process comprises providing at least one monomer capable of forming an electrically conductive conjugated polymer, and a suitable substrate having a substrate surface, subjecting the substrate surface to a surface treatment step to improve abrasion resistance, and exposing the substrate surface to a vapour of the monomer to form an electrically conductive conjugated polymer coating thereon.

Photochromic wool fabric by sol-gel coating

This thesis investigates the possibility of producing photochromic wool fabrics using a silica sol-gel coating method. Silicas made from sol-gel methods are uniquely suited to host photochromic dyes for developing colour-changing wool. The achieved photochromic effects have opened a new product area for fashion effects on wool textiles.

Robust, self-healing superamphiphobic fabrics prepared by two-step coating of fluoro-containing polymer, fluoroalkyl silane, and modified silica nanoparticles

A robust, superamphiphobic fabric with a novel self-healing ability to autorepair from chemical damage is prepared by a two-step wet-chemistry coating technique using an easily available material system consisting of poly(vinylidene fluoride-co-hexafluoropropylene), fluoroalkyl silane, and modified silica nanoparticles. The coated fabrics can withstand at least 600 cycles of standard laundry and 8000 cycles of abrasion without apparently changing the superamphiphobicity. The coating is also very stable to strong acid/base, ozone, and boiling treatments. After being damaged chemically, the coating can restore its super liquid-repellent properties by a short-time heating treatment or room temperature ageing. This simple but novel and effective coating system may be useful for the development of robust protective clothing for various applications.

Excellent electrochemical performance of LiFe0.4Mn0.6PO4 microspheres produced using a double carbon coating process

Composite LiFe0.4Mn0.6PO4/C microspheres are considered advanced cathode materials for electric vehicles and other high-energy density applications due to their advantages of high energy density and excellent cycling stability. LiFe0.4Mn0.6PO4/C microspheres have been produced using a double carbon coating process employing traditional industrial techniques (ball milling, spray-drying and annealing). The obtained LiFe0.4Mn0.6PO4 microspheres exhibit a high discharge capacity of around 166 mA h g-1 at 0.1 C and excellent rate capabilities of 132, 103, and 72 mA h g-1 at 5, 10, and 20 C, respectively. A reversible capacity of about 152 mA h g-1 after 500 cycles at a current density of 1 C indicates an outstanding cycling stability. The excellent electrochemical performance is attributed to the micrometer-sized spheres of double carbon-coated LiFe0.4Mn0.6PO4 nanoparticles with improved electric conductivity and higher Li ion diffusion coefficients, ensuring full redox reactions of all nanoparticles. The results show that the advanced high-energy density cathode materials can be produced using existing industry techniques.

Effect of different carbon-coating ways on the microstructure and electrochemical performance of LiFePO4/C cathodes

Through comparative studying on LiFePO4/C preparation process of adding carbon source in precursor and pre-sintered material, marked as LFP-1 (in-situ carbon coating) and LFP-2 respectively, by means of C-S test, XRD, SEM, BET, Raman, the effects of carbon content, morphology, particle size and surface carbon structure on the electrochemical performance of LiFePO4/C cathodes were investigated. SEM images showed that particle sizes of LFP-1 and LFP-2 are about 10μm and 100nm respectively. The EIS and galvnostatic charge-discharge tests indicated that LFP-1 has lower charge transfer resistance (Rct), better rate and cycle performance than that of LFP-2, which can be attributed to the different microstructure and the higher degree of graphitized carbon of LiFePO4/C. Raman spectroscopic analysis showed that the ratio of the ID/IG and Asp3/Asp2 of LFP-1 is lower that of LFP-2, which means the degree of graphitized carbon of LFP-1 is higher than that of LEP-2. These results have important significance for improving the overall performance of olivine cathode materials for lithium ion batteries.

Structural health monitoring: a practical approach to achieving in-situ and site-specific warning of pipeline corrosion and coating failure

An approach to achieving the ambitious goal of cost effectively extending the safe operation life of energy pipelines to, for instance, 100 years is the application of structural health monitoring and life prediction tools that are able to provide long-term remnant pipeline life prediction and in-situ pipeline condition monitoring. A critical step in pipeline structural health monitoring is the enhancement of technological capabilities that are required for quantifying the effects of key factors influencing buried pipeline corrosion and environmentally assisted materials degradation, and the development of condition monitoring technologies that are able to provide in-situ monitoring and site-specific warning of pipeline damage. This paper provides an overview of our current research aimed at developing new sensors for monitoring, categorising and quantifying the level and nature of external pipeline and coating damages under the combined effects of various inter-related variables and processes such as localised corrosion, coating damage and disbondment, cathodic shielding. The concept of in-situ monitoring and site-specific warning of pipeline corrosion is illustrated by a case of monitoring localised corrosion under disbonded coatings using a new corrosion monitoring probe. A basic principle that underpins the use of sensors to monitor localised corrosion has been presented: Localised corrosion and coating failure are not an accidental occurrence, it occurs as the result of fundamental thermodynamic instability of a metal exposed to a specific environment. Therefore corrosion and coating disbondment occurring on a pipeline will also occur on a sensor made of the same material and exposed to the same pipeline condition. Although the exact location of localised corrosion or coating disbondment could be difficult to pinpoint along the length of a buried pipeline, the ‘worst-case scenario’ and high risk pipeline sections and sites are predictable. Sensors can be embedded at these strategic sites to collect data that contain ‘predictor features’ signifying the occurrence of localised corrosion, CP failure, coating disbondment and degradation. Information from these sensors will enable pipeline owners to prioritise site survey and inspection operations, and to develop maintenance strategy to manage aged pipelines, rather than replace them.

Effect of WC-10%Co-4%Cr coating on the Ti-6Al-4V alloy fatigue strength

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Evaluation of WC-10Ni thermal spray coating with shot peening on the fatigue strength of AISI 4340 steel

Fatigue failure is a result of a crack initiation and propagation, in consequence of a cyclical load. In aeronautical components as landing gear the fatigue strength is an important parameter to be considered in project, as well as the corrosion and wear resistance.The thermal sprayed HVOF technology it's normally used to protect components against wear and corrosion, and are being considerate an alternative to replace chromium by the aeronautical industry. With respect to fatigue life, the HVOF technique induces residual stress on the interface. In the case of tensile residual stresses, the initiation and propagation phases of fatigue process are accelerated; on the other hand, compressive residual stresses close to the surface may increase fatigue life. The technique to improve the coated materials fatigue strength is the shot peening process, which induces residual stress in the surface in order to delay the nucleation and propagation process.The aim of present study is to compare the influence of WC-10 Ni coating applied by HVOF on the fatigue strength of AISI 4340 steel, with and without shot peening. S-N curves were obtained in axial fatigue tests for material base, and tungsten carbide coated specimens. (C) 2010 Published by Elsevier Ltd.

Biomimetic calcium phosphate coating on Ti-7.5Mo alloy for dental application

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The Effect of Coating Patterns with Spinel-Based Investment on the Castability and Porosity of Titanium Cast into Three Phosphate-Bonded Investments

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)