Gold-plated Wires Research Articles

Elemental composition, corrosion resistance and mechanical properties of computer-aided design and computer-aided manufacturing fixed retainers versus conventional fixed retainers.

To investigate the elemental composition, corrosion resistance, and mechanical properties of computer-aided design and computer-aided manufacturing (CAD-CAM) retainers versus conventional fixed retainers (FRs). Eight different retainer wires were investigated. Energy dispersive X-ray spectroscopy was used to determine the elemental composition. Leakage was analysed according to ISO 10271:2020 guidelines. Hardness was tested using the Vickers method with a load of 0.3 kg. The tensile force and tensile strength were evaluated. Multiple comparisons among wires of hardness, tensile force, and strength were conducted using the Welch t-test, with Bonferroni correction. Nickel was present in all wires. The CAD-CAM-FR wire, which contained more nickel than the other wires, had no measurable leakage. The gold-plated wires had the highest total leakage, but did not exceed the ISO standard limit. The hardness of the stainless-steel twisted wires was the highest and that of the CAD-CAM-FR wire was the lowest. The tensile strength of the CAD-CAM-FR wire was significantly lower than that of the other wires and similar to the other twisted-wire retainers. The CAD-CAM-FR wire is likely to have high corrosion resistance and flexibility due to its low hardness.

A single-walled carbon nanotubes-based electrochemical impedance immunosensor for on-site detection of Listeria monocytogenes.

Real-time and sensitive detection of pathogenic bacteria in food is in high demand to ensure food safety. In this study, a single-walled carbon nanotubes (SWCNTs)-based electrochemical impedance immunosensor for on-site detection of Listeria monocytogenes (L. monocytogenes) was developed. A gold-plated wire was functionalized using polyethylenimine (PEI), SWCNTs, streptavidin, biotinylated L. monocytogenes antibodies, and bovine serum albumin (BSA). A linear relationship (R2 =0.982) between the electron transfer resistance measurements and concentrations of L. monocytogenes within the range of 103 -108 CFU/ml was observed. In addition, the sensor demonstrated high selectivity towards the target in the presence of other bacterial cells such as Salmonella Typhimurium and Escherichia coli O157:H7. To facilitate the demand for on-site detection, the sensor was integrated into a smartphone-controlled biosensor platform, consisting of a compact potentiostat device and a smartphone. The signals from the proposed platform were compared with a conventional potentiostat using the immunosensor interacted with L. monocytogenes (103 -105 CFU/ml). The signals obtained with both instruments showed high consistency. Recovery percentages of lettuce homogenate spiked with 103 , 104 , and 105 CFU/ml of L. monocytogenes obtained with the portable platform were 90.21, 90.44, and 93.69, respectively. The presented on-site applicable SWCNT-based immunosensor platform was shown to have a high potential to be used in field settings for food and agricultural applications. PRACTICAL APPLICATION: The developed immunosensor was developed for on-site detection of L. monocytogenes. The limit of detection of the sensor was 103 CFU/ml with a detection time of 10min. In order to facilitate the requirements for effective on-site screening for food safety, the sensor was integrated into a smartphone-controlled platform, so that the bio-molecular interactions were converted into impedance signals and transmitted wirelessly to a smartphone by a hand-held EIS transducer.

Fully integrated sampler and dilutor in an electrochemical paper-based device for glucose sensing

An electroanalytical platform capable to take and dilute the sample has been designed in order to fully integrate the different steps of the analytical process in only one device. The concept is based on the addition of glass-fiber pads for sampling and diluting to an electrochemical cell combining a paper-based working electrode with low-cost connector headers as counter and reference electrodes. In order to demonstrate the feasibility of this all-in-one platform for biosensing applications, an enzymatic sensor for glucose determination (requiring a potential as low as −0.1 V vs. gold-plated wire by using ferrocyanide as mediator) was developed. Real food samples, such as cola beverages and orange juice, have been analyzed with the bioelectroanalytical lab-on-paper platform. As a proof-of-concept, and trying to go further in the integration of steps, sucrose was successfully detected by depositing invertase in the sampling strip. This enzyme hydrolyzes sucrose into fructose and glucose, which was determined using the enzymatic biosensor. This approach opens the pathway for the development of devices applying the lab-on-paper concept, saving costs and time, and making possible to perform decentralized analysis with high accuracy.Graphical abstract

Reinforcement of photosensitive material for bases of orthodontic appliances

The objective of the study was to improve the strength properties polymer by modifying its basis with various materials. A polymer in the form of a pink-colored plasticine mass with veins was studied, a quartz mesh «Quartz splint mesh» manufactured by RTD (France) and two metal gold-plated wire mesh (0.1 mm and 0.15 mm in diameter) manufactured by Renfert (Germany). Modified test specimens, 65×40×3.5 mm in size were covered with a lavsan film and at a slight pressure the material was rolled out with a glass cylinder flush with the frame. Curing was carried out in Fhotopress photopolymer (Aveyron, RF) under the 460-470 nm wavelength light for 6 minutes on each side. The plates were sawn with a mill in the form of strips 64×10×3.3 mm and kept in distilled water at 37 °C for 50 h before testing. The test of the reinforced samples was carried out with a middle and lower location of quartz and metal grids pre-treated with adhesive and subjected to a 4-point bending test. Bending strength, bending modulus, and fracture deformation were determined using a Zwick/Roell Z010 testing machine with a constant crosshead speed under loading (5±1) mm/min. The statistical significance of the influence of reinforcing elements on the performance of the basic physical and mechanical properties of the base material was determined using Student's t-test. The value of fracture toughness index K1 at the lower location of the quartz mesh was 3.72±0.43 MN/m1.5, which was 4.9 times significantly higher than K1 for the non-reinforced material (p=0.0001). The ability to achieve maximum material strength with the lower reinforcement method increases the functional usefulness of removable orthodontic and orthopedic structures with a basis of «Nolatek» light-cured material.

A novel behaviour of dynamic magnetization process in gold-plated CoFeSiB amorphous wires

Dynamic magnetization processes in CoFeSiB amorphous wires with bamboo domain structures have been studied with observations of ac voltage-current relations of the wires depending on dc bias magnetic fields. A novel behaviour of the dynamic magnetization processes is found in the gold-plated wires. This novel behaviour is useful for improvement of performances in magnetic-field-sensing devices using the wires.

The aging of wire chambers filled with dimethyl ether: wire and construction materials and freon impurities

This is a complete summary of our study of the aging of different types of wire chambers, with a variety of construction materials and wires, filled with dimethyl ether (DME) of varying degrees of purity. The resistive Nicotin and Stablohm wires were corroded by DME, producing fast aging. The moderately resistive stainless steel wires were able to withstand extended irradiation (up to 1 C/cm) in high-purity DME without any apparent damage; and gold-plated tungsten and molybdenum wires exhibited a comparable behavior. Many construction materials were tested and recommendations are thus reached as to what kinds of materials are safe in building DME-operated wire chambers. Among many different Freon and hydrocarbon impurities detected in DME by means of gas chromatography (GC), Freon-11 was found to be mostly responsible for the aging, even with noncorrosive stainless steel or gold-plated wires. The availability and feasibility of obtaining Freon-free DME is reported as well.

Some results on the ageing of wire chambers with dimethyl ether

Ageing results of three test wire detectors when filled with dimethyl ether (DME) are presented. DME gas was analyzed before and during the tests for the presence of electronegative impurities, such as Freons. A strong dependence of the rate of ageing on the wire composition was observed. The resistive wires, such as Stablohm and Nicotin, produced fast ageing. Also, even the best available purified DME, as of today, used with gold-plated wires, produced some slow ageing. The rate of amplitude decrease depended on the Freon impurity level.