Room temperature detection of aspergillus flavus volatile organic compounds (VOCs) under simulated conditions using graphene oxide and tin oxide Nanorods (SnO NRs-GO).

This study investigated the application of a hybrid nanocomposite of tin oxide nanorods (SnO NRs) and graphene oxide (GO) for the chemoresistive detection of some volatile compounds (hexanal, benzaldehyde, octanal, 1-octanol, and ethyl acetate vapours) emitted by Aspergillus flavus under simulated conditions. The synthesised materials were characterised using various analytical techniques, including high-resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) analysis, and Fourier transform infrared spectroscopy (FTIR). Three sensors were fabricated: individual nanomaterials (i.

Morphed aflaxotin concentration produced by strain VKMN22 on maize grains inoculated on agar culture.

This study identified and monitored the levels of aflatoxins (B and B) produced by isolate VKMN22 (OP355447) in maize samples sourced from a local shop in Johannesburg, South Africa. Maize samples underwent controlled incubation after initial rinsing, and isolates were identified through morphological and molecular methods. In another experiment, autoclaved maize grains were intentionally re-inoculated with the identified fungal isolate using spore suspension (106 spore/mL), after which 1 g of the contaminated maize sample was inoculated on PDA media and cultured for seven days.

Recent advancements in the use of plastics as a carbon source for carbon nanotubes synthesis - A review.

Plastics, which majorly consist of polypropylene (PP), polyethylene (linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE) and high-density polyethylene (HDPE)), polystyrene (PS), polyvinyl chloride (PVC), polyethylene terephthalate (PET), etc., are the most abundant municipal solid wastes (MSW). They have been utilized as a cheap carbon feedstock in the synthesis of carbon nanotubes (CNTs) because of their high hydrocarbon content, mainly carbon and hydrogen, especially for the polyolefins.

Zeolitic imidazolate framework as humidity-resistant solid state-chemiresistive gas sensors: A review.

With significant technological advances, solid-state gas sensors have been extensively applied to detect toxic gases and volatile organic compounds (VOCs) in confined areas such as indoor environments and industries and to identify gas leakage. Semiconductor metal oxides are the primary sensing materials, although their major drawbacks include a lack of sensitivity, poor performance at high humidity, and operating at high temperatures ranging between 140 and 400 °C. Recently, the use of zeolitic imidazolate frameworks (ZIFs) in gas sensors has received considerable attention as a promising material to overcome the drawbacks possessed by semiconductor metal oxide-based gas sensors.

Exploration of the Different Dimensions of Wurtzite ZnO Structure Nanomaterials as Gas Sensors at Room Temperature.

In this work, we report on the synthesis of four morphologies of ZnO, namely, nanoparticles, nanorods, nanosheets, and nanoflowers, from a single precursor Zn(CHCOO)·2HO under different reaction conditions. The synthesised nanostructured materials were characterised using powder X-ray diffraction (XRD), Fourier transform infrared (FTIR) and Raman spectroscopy, UV-Vis, XPS analysis, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and nitrogen sorption at 77 K. The XRD, FTIR, and Raman analyses did not reveal any significant differences among the nanostructures, but differences in the electronic properties were noted among the different morphologies.

Aflatoxins: Occurrence, biosynthesis, mechanism of action and effects, conventional/emerging detection techniques.

Aflatoxins (AFs) are toxic secondary metabolites prevalent in various food and agricultural products, posing significant challenges to global food safety. The detection and quantification of AFs through high-precision analytical techniques are crucial in mitigating AF contamination levels and associated health risks. Variousmethods,including conventional and emerging techniques, have been developed for detecting and quantifyingAFsinfood samples.

A humidity-resistant and room temperature carbon soot@ZIF-67 composite sensor for acetone vapour detection.

Zeolitic imidazolate framework-67 (ZIF-67), carbon nanoparticles (CNPs), and the CNPs@ZIF-67 composite were prepared and used to fabricate sensors for the detection of acetone vapour. The prepared materials were characterized using transmission electron microscopy, powder X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy and Fourier-transform infrared spectroscopy. The sensors were tested using an LCR meter under the resistance parameter.

Selective detection of methanol vapour from a multicomponent gas mixture using a CNPs/ZnO@ZIF-8 based room temperature solid-state sensor.

Methanol vapour is harmful to human health if it is inhaled, swallowed, or absorbed through the skin. Solid-state gas sensors are a promising system for the detection of volatile organic compounds, unfortunately, they can have poor gas selectivity, low sensitivity, an inferior limit of detection (LOD), sensitivity towards humidity, and a need to operate at higher temperatures. A novel solid-state gas sensor was assembled using carbon nanoparticles (CNPs), prepared from a simple pyrolysis reaction, and zinc oxide@zeolitic imidazolate framework-8 nanorods (ZnO@ZIF-8 nanorods), synthesised using a hydrothermal method.

Corn Cob Char as Catalyst Support for Developing Carbon Nanotubes from Waste Polypropylene Plastics: Comparison of Activation Techniques.

The future and continuity of nanomaterials are heavily dependent on their availability and affordability. This could be achieved when cheap materials are actively employed as starting materials for nanomaterials synthesis. In this study, waste corn cob char was used as support during the preparation of the NiMo catalyst, and the effect of different char-activating techniques on the microstructure, yield and quality of carbon nanotubes (CNTs) obtained from waste polypropylene (PP) plastics using the chemical vapor deposition (CVD) technique was investigated.

Nickel Oxide-Carbon Soot-Cellulose Acetate Nanocomposite for the Detection of Mesitylene Vapour: Investigating the Sensing Mechanism Using an LCR Meter Coupled to an FTIR Spectrometer.

Nanocomposite sensors were prepared using carbon soot (CNPs), nickel oxide nanoparticles (NiO-NPs), and cellulose acetate (CA), which was used to detect and study the sensing mechanism of mesitylene vapour at room temperature. Synthesised materials were characterised using high-resolution transmission electron microscopy (HR-TEM), powder x-ray diffraction (PXRD), Raman spectroscopy, and nitrogen sorption at 77 K. Various sensors were prepared using individual nanomaterials (NiO-NPs, CNPs, and CA), binary combinations of the nanomaterials (CNPs-NiO, CNPs-CA, and NiO-CA), and ternary composites (NiO-CNPs-CA).

Novel Chemoresistive Sensor for Sensitive Detection of Pb Ions Using an Interdigital Gold Electrode Fabricated with a Reduced Graphene Oxide-Based Ion-Imprinted Polymer.

This study presents novel chemoresistive reduced graphene oxide-ion-imprinted polymer (IIP-rGO)-based sensors for detection of lead (Pb) ions. The ion-imprinted polymer was synthesized by bulk polymerization and modified with a variable amount of rGO incorporated to form an IIP-rGO composite. The amount of rGO in the polymer matrix affected the sensor's relative response, and 1:3 mass ratio produced excellent results, with a consistent trend as the concentration of Pb ions increased in the solution.

Concomitant in Situ FTIR and Impedance Measurements To Address the 2-Methylcyclopentanone Vapor-Sensing Mechanism in MnO-Polymer Nanocomposites.

Polymer nanocomposite-based sensors were prepared using cellulose acetate (CA), carbon nanoparticles (CNPs), and manganese dioxide (MnO) nanorods to detect and to understand the sensing mechanism of 2-methylcyclopentanone vapor. A sensor with a mass ratio of 1:1.5:3 of MnO/CNPs/CA as well as MnO/CA and MnO/CNP composite and MnO sensors were prepared.

Chemical Vapour Deposition of MWCNT on Silica Coated FeO and Use of Response Surface Methodology for Optimizing the Extraction of Organophosphorus Pesticides from Water.

Multiwalled carbon nanotube (MWCNT) was fixed onto the surface of a magnetic silica (FeO@SiO) substrate via chemical vapour deposition (CVD). Acetylene gas was used as the carbon source and cobalt oxide as the catalyst. The chemical and physical characteristics of the materials were investigated by transmission electron microscopy (TEM), Raman spectroscopy (RS), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), and nitrogen adsorption/desorption isotherm.

The effects of two-dimensional TiSe on the thermoelectric, electronic and optical response of YbMnSb/AlSbYb heterostructures - A theoretical study.

Two-dimensional TiSe, with YbMnSb and AlSbYb thermoelectric materials, were used to generate heterostructures. The electronic and optical calculations were done using the Materials Studio 2018 modelling software package, employing the Cambridge Serial Total Energy Package code and using the generalised gradient approximation with Perdew-Burke-Ernzerhof exchange-correlation functionals. However, the electronic results obtained revealed a reduction in the calculated band gap and an increase in the slope of the density of state at the Femi level, as well as the energy bands of the generated heterostructures was reported.

Functionalized spherical carbon nanostructure/poly(vinylphenol) composites for application in low power consumption write-once-read-many times memories.

We apply functionalized carbon nanoshell and carbon sphere based composites in poly(vinylphenol) matrix in write-once-read-many-times memory elements. The devices based on carbon nanoshells show an ON/OFF current ratio of 10(5) and long-term information retention. The functionalized carbon nanoshells and carbon spheres show improved dispersion in the poly(vinylphenol) matrix, allowing the preparation of homogeneous films even at the submicrometer scale.

Nitrogen-doped, boron-doped and undoped multiwalled carbon nanotube/polymer composites in WORM memory devices.

We report the preparation of write-once-read-many times memory devices using composites of carbon nanotubes and poly(vinyl phenol) sandwiched between Al electrodes. Three types of nanotubes (undoped multiwalled carbon nanotubes, nitrogen-doped multiwalled carbon nanotubes and boron-doped multiwalled carbon nanotubes) are investigated for this application. The OFF to ON state switching threshold is only slightly dependent on nanotube type, but the ON/OFF current ratio depends on both nanotube type and concentration and varies up to 10(6), decreasing for nanotube concentrations larger than 0.

Electronic detection of Drechslera sp. fungi in charentais melon ( Cucumis melo Naudin) using carbon-nanostructure-based sensors.

The development of chemical sensor technology in recent years has stimulated an interest regarding the use of characteristic volatiles and odors as a rapid and early indication of deterioration in fruit quality. The fungal infestation by Drechslera sp. in melons is a severe problem, and we demonstrate that electronic sensors based on carbon nanostructures are able to detect the presence of these fungi in melon.

Composites of polyvinyl alcohol and carbon (coils, undoped and nitrogen doped multiwalled carbon nanotubes) as ethanol, methanol and toluene vapor sensors.

We investigate the chemical sensing behavior of composites prepared with polyvinyl alcohol and carbon materials (undoped multiwalled carbon nanotubes, nitrogen-doped multiwalled carbon nanotubes and carbon nanocoils). We determine the sensitivity of thin films of these composites for ethanol, methanol and toluene vapor, comparing their conductance and capacitance responses. The composite that exhibits highest sensitivity depends on specific vapor, vapor concentration and measured electrical response, showing that the interactivity of the carbon structure with chemical species depend on structural specificities of the carbon structure and doping.

The in vitro antitumour activity of novel, mitochondrial-interactive, gold-based lipophilic cations.

In this study we compared the effects of two previously described antimitochondrial gold complexes, that is, [A] [Au(dppe)(2)]Cl and [B] [Au(d4pype)(2)]Cl with two novel lipophilic cations, that is, [C] [Au(dpmaaH(2))(dpmaaSnMe(2))]Cl and [D] [Au(dpmaaSnMe(2))(2)]Cl as antimitochondrial agents. The results of this study indicate that [C] and [D] have intermediate partition coefficients and exhibited a selective uptake by cells. They exhibited a higher selectivity for the various cell lines than [A] but were more cytotoxic than [B].