Mutation of the Maturase Lipoprotein Attenuates the Virulence of Streptococcus equi to a Greater Extent than Does Loss of General Lipoprotein Lipidation Andrea Hamilton,†‡ Carl Robinson,† Iain C. Sutcliffe, Josh Slater, Duncan J. Maskell, Nick Davis-Poynter, Ken Smith, Andrew Waller, and Dean J. Harrington* University of Sunderland, SR1 3SD Tyne and Wear, United Kingdom; Animal Health Trust, Lanwades Park, Kentford, Newmarket, Suffolk CB8 7UU, United Kingdom; Northumbria University, Newcastle upon Tyne NE1 8ST, United Kingdom; Royal Veterinary College, Hertfordshire AL9 7TA, United Kingdom; Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES, United Kingdom; and University of Bradford, West Yorkshire BD7 1DP, United Kingdom

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Infection and immunity

This paper presents an overview of the work done on graphene in recent years. It explains the preparation techniques, the properties of graphene related to its physio-chemical structure and some key applications. Graphene, due to its outstanding electrical, mechanical and thermal properties, has been one of the most popular choices to develop the electrodes of a sensor. It has been used in different forms including nanoparticle and oxide forms. Along with the preparation and properties of graphene, the categorization of the applications has been done based on the type of sensors. Comparisons between different research studies for each type have been made to highlight their performances. The challenges faced by the current graphene-based sensors along with some of the probable solutions and their future opportunities are also briefly explained in this paper.

Graphene and its sensor-based applications: A review

Recent progress in the synthesis of graphene and derived materials for next generation electrodes of high performance lithium ion batteries

Inkjet printing is recognised as an efficient method for direct deposition of functional materials on flexible substrates in predesigned patterns owing to simple processing, low cost and higher adaptability for large scale fabrication of electronic devices, sensors, light emitting diodes, etc. Inks used in inkjet printing mostly consist of organic polymers, metal nanoparticles and carbon materials such as graphene and carbon nanotubes. For effectiveness of the printing process, the fluid dynamic parameters such as viscosity and surface tension, as well as dimensionless quantities such as the Weber number, Reynolds number, and Ohnesorge number, must be within a suitable limit. More frequently, this process suffers due to the formation of a coffee ring during the post printing process, which affects the morphology as well as electrical conductivity of the printed pattern. In this review, we have summarized the various aspects of inks such as fluid dynamical parameters of inks, mechanism of the coffee ring formation, different types of ink preparation strategies and their applications in sensors, thin film transistors, and energy storage devices.

A review on inkjet printing of nanoparticle inks for flexible electronics

The first surface acoustic wave (SAW) sensor that functions via changes in conductivity of a thin surface film is reported. A lead phthalocyanine (PbPc) thin film is deposited on the acoustic propagation path of a LiNbO 3 SAW delay line, which serves as the feedback element of an oscillator circuit. Reaction with strongly oxidizing gases, in particular NO 2 , increases the conductivity of the PbPc film. Acousto-electric coupling of the traveling electric potential wave associated with the SAW to charge carriers in the PbPc film slows the acoustic wave velocity, altering the oscillation frequency of the circuit. This sensor is about 1000 times more sensitive, in terms of the number of NO 2 molecules that can be detected (10 16 molecules/cm 3 of PbPc film), than an identical SAW sensor functioning via mass loading would be. Sensitivity to a few ppm of NO 2 in N 2 has been demonstrated.

Surface acoustic wave gas sensor based on film conductivity changes

Synthesis of Graphene Oxide using Modified Hummers Method: Solvent Influence

The performance of sensing surfaces highly relies on nanostructures to enhance their sensitivity and specificity. Herein, nanostructured zinc oxide (ZnO) thin films of various thicknesses were coated on glass and p-type silicon substrates using a sol-gel spin-coating technique. The deposited films were characterized for morphological, structural, and optoelectronic properties by high-resolution measurements. X-ray diffraction analyses revealed that the deposited films have a c-axis orientation and display peaks that refer to ZnO, which exhibits a hexagonal structure with a preferable plane orientation (002). The thicknesses of ZnO thin films prepared using 1, 3, 5, and 7 cycles were measured to be 40, 60, 100, and 200 nm, respectively. The increment in grain size of the thin film from 21 to 52 nm was noticed, when its thickness was increased from 40 to 200 nm, whereas the band gap value decreased from 3.282 to 3.268 eV. Band gap value of ZnO thin film with thickness of 200 nm at pH ranging from 2 to 10 reduces from 3.263eV to 3.200 eV. Furthermore, to evaluate the transducing capacity of the ZnO nanostructure, the refractive index, optoelectric constant, and bulk modulus were analyzed and correlated. The highest thickness (200 nm) of ZnO film, embedded with an interdigitated electrode that behaves as a pH-sensing electrode, could sense pH variations in the range of 2-10. It showed a highly sensitive response of 444 μAmM-1cm-2 with a linear regression of R2 =0.9304. The measured sensitivity of the developed device for pH per unit is 3.72μA/pH.

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Low Temperature Annealed Zinc Oxide Nanostructured Thin Film-Based Transducers: Characterization for Sensing Applications.

Highly sensitive Escherichia coli shear horizontal surface acoustic wave biosensor with silicon dioxide nanostructures.

Novel synthesis of silicon carbide nanotubes by microwave heating of blended silicon dioxide and multi-walled carbon nanotubes: The effect of the heating temperature

SiC nanowhiskers (SiCNWs), due to their unique properties such as high thermal stability, high strength, high thermal conductivity and large band gap, lead to a wide range of applications. In this article, synthesis of SiCNWs was performed by using microwave heating. Silica and graphite in the ratio of 1:3 were mixed in an ultrasonic bath, dried on a hotplate and cold pressed uniaxially into a pellet die. The pellets were heated by using a laboratory microwave furnace to 1400 °C with a heating rate of 20 °C min−1 and heated for 20, 40 and 60 min. Characterizations of the as synthesized SiCNWs were done to study the effect of heating duration on the morphology and properties of SiCNWs. A time of 40 min was found to be the most ideal heating duration for the synthesis of SiCNWs. β-SiC appeared as the only phase in the x-ray diffraction pattern for SiCNWs formed by using 40 and 60 min of heating duration with no traces of unreacted silica and graphite. Field emission scanning electron microscopy imaging confirmed that no trace of graphite or silica was present in SiCNWs synthesized by a heating duration of 40 and 60 min. Energy dispersive x-ray spectroscopy analysis revealed that only elemental C and Si were present for SiCNWs synthesized at 40 and 60 min. Meanwhile, photoluminescence spectroscopy indicated the presence of single phase β-SiC peak at 440 nm was associated with band gap of 2.8 eV. Absorption bands of Si–C bond were detected at 802.4 cm−1 in the spectra of fourier transform infrared analysis. SiCNWs produced by heating at 40 and 60 min have high thermal stability with weight loss lower than 6%. A simple process that involved two steps of ultrasonic mixing and microwave heating of graphite and SiO2 is proposed as a new route for the synthesis of SiCNWs.

https://iopscience.iop.org/article/10.1088/2053-1591/aa5248/pdf

K.L. Foo

Papers

Synthesis of Graphene Oxide using Modified Hummers Method: Solvent Influence

Low Temperature Annealed Zinc Oxide Nanostructured Thin Film-Based Transducers: Characterization for Sensing Applications.

Highly sensitive Escherichia coli shear horizontal surface acoustic wave biosensor with silicon dioxide nanostructures.

Novel synthesis of silicon carbide nanotubes by microwave heating of blended silicon dioxide and multi-walled carbon nanotubes: The effect of the heating temperature

Synthesis of silicon carbide nanowhiskers by microwave heating: effect of heating duration