Room-Temperature Ammonia Sensing Using Polyaniline-Coated Laser-Induced Graphene.

The reliable detection of ammonia at room temperature is crucial for not only maintaining environmental safety but also for reducing the risks of hazardous pollutants. In this study, the electrochemical modification of laser-induced graphene (LIG) with polyaniline (PANI) led to the development of a chemo-resistive nanocomposite (PANI@LIG) for detecting ammonia levels at room temperature. The composite is characterized by field emission scanning electron microscopy, Fourier transforms infrared, and Raman and X-ray photoelectron spectroscopy.

Application of digital twins for simulation based tailoring of laser induced graphene.

In the era of man-machine interfaces, digital twins stand as a key technology, offering virtual representations of real-world objects, processes, and systems through computational models. They enable novel ways of interacting with, comprehending, and manipulating real-world entities within a virtual realm. The real implementation of graphene-based sensors and electronic devices remains challenging due to the integration complexities of high-quality graphene materials with existing manufacturing processes.

ZnO Decorated Graphene-Based NFC Tag for Personal NO Exposure Monitoring during a Workday.

This paper presents the integration of a sensing layer over interdigitated electrodes and an electronic circuit on the same flexible printed circuit board. This integration provides an effective technique to use this design as a wearable gas measuring system in a target application, exhibiting high performance, low power consumption, and being lightweight for on-site monitoring. The wearable system proves the concept of using an NFC tag combined with a chemoresistive gas sensor as a cumulative gas sensor, having the possibility of holding the data for a working day, and completely capturing the exposure of a person to NO concentrations.

The Effect of Repeated Blood Harvesting from Pregnant Mares on Haematological Variables.

Studies have been carried out on the effect of large-volume blood harvesting from horses, but they were performed on nonpregnant horses of various breeds other than Icelandic horses. This study aimed to investigate the effect on the haematological variables indicating erythropoiesis of repeated blood harvesting from pregnant mares. To account for regional variation, two herds of mares were chosen, both kept under free-range conditions.

ZnO-Loaded Graphene for NO Gas Sensing.

This paper investigates the effect of decorating graphene with zinc oxide (ZnO) nanoparticles (NPs) for the detection of NO. In this regard, two graphene sensors with different ZnO loadings of 5 wt.% and 20 wt.

On the Use of Pulsed UV or Visible Light Activated Gas Sensing of Reducing and Oxidising Species with WO and WS Nanomaterials.

This paper presents a methodology to quantify oxidizing and reducing gases using n-type and p-type chemiresistive sensors, respectively. Low temperature sensor heating with pulsed UV or visible light modulation is used together with the application of the fast Fourier transform (FFT) to extract sensor response features. These features are further processed via principal component analysis (PCA) and principal component regression (PCR) for achieving gas discrimination and building concentration prediction models with R values up to 98% and RMSE values as low as 5% for the total gas concentration range studied.

LoRa Sensor Network Development for Air Quality Monitoring or Detecting Gas Leakage Events.

During the few last years, indoor and outdoor Air Quality Monitoring (AQM) has gained a lot of interest among the scientific community due to its direct relation with human health. The Internet of Things (IoT) and, especially, Wireless Sensor Networks (WSN) have given rise to the development of wireless AQM portable systems. This paper presents the development of a LoRa (short for long-range) based sensor network for AQM and gas leakage events detection.

Special Issue "Advanced Nanomaterials Based Gas Sensors".

During the last several years, according to the works published in research journals, many nanostructured materials have been tested as sensing materials for gas-sensing applications. This trend has been observed for both metal oxides as well as carbon-based nanomaterials. More recently, it has also been extended to other materials based on chalcogenides.

Gas sensing properties of individual SnO nanowires and SnO sol-gel nanocomposites.

This work is an investigation of the properties of semiconductor materials based on metal oxides, their catalytic properties, and their application as gas sensors, which were shown to exhibit high sensitivity, stability, and selectivity to target gases. The aim of this work is the comparison of gas sensing properties of tin dioxide in the form of individual nanowires and nanopowders obtained by sol-gel synthesis. This comparison is necessary because the traditional synthesis procedures of small particle, metal oxide materials seem to be approaching their limit.

Wet chemistry route for the decoration of carbon nanotubes with iron oxide nanoparticles for gas sensing.

In this work, we investigated the parameters for decorating multiwalled carbon nanotubes with iron oxide nanoparticles using a new, inexpensive approach based on wet chemistry. The effect of process parameters such as the solvent used, the amount of iron salt or the calcination time on the morphology, decoration density and nanocluster size were studied. With the proposed approach, the decoration density can be adjusted by selecting the appropriate ratio of carbon nanotubes/iron salt, while nanoparticle size can be modulated by controlling the calcination period.

Using the Transient Response of WO₃ Nanoneedles under Pulsed UV Light in the Detection of NH₃ and NO₂.

Here we report on the use of pulsed UV light for activating the gas sensing response of metal oxides. Under pulsed UV light, the resistance of metal oxides presents a ripple due to light-induced transient adsorption and desorption phenomena. This methodology has been applied to tungsten oxide nanoneedle gas sensors operated either at room temperature or under mild heating (50 °C or 100 °C).

Enhanced detection of nitrogen dioxide via combined heating and pulsed UV operation of indium oxide nano-octahedra.

We report on the use of combined heating and pulsed UV light activation of indium oxide gas sensors for enhancing their performance in the detection of nitrogen dioxide in air. Indium oxide nano-octahedra were synthesized at high temperature (900 °C) via vapour-phase transport and screen-printed onto alumina transducers that comprised interdigitated electrodes and a heating resistor. Compared to the standard, constant temperature operation of the sensor, mild heating (e.

Comparison of Vibrio spp. populations found in seawater, in exhibition aquaria, in fish intestine and in fish feed.

Aims: Vibrio populations in the seawater supply and the water of seven exhibition aquaria that simulate various Mediterranean and tropical ecosystems were compared. The similarity of Vibrio populations in the intestine of various fish species, feed and water was examined. Resistance to the antibiotics used in fish health management was analysed for the dominant Vibrio isolates.

Carbon nanotube-TiO(2) hybrid films for detecting traces of O(2).

Hybrid titania films have been prepared using an adapted sol-gel method for obtaining well-dispersed hydrogen plasma-treated multiwall carbon nanotubes in either pure titania or Nb-doped titania. The drop-coating method has been used to fabricate resistive oxygen sensors based on titania or on titania and carbon nanotube hybrids. Morphology and composition studies have revealed that the dispersion of low amounts of carbon nanotubes within the titania matrix does not significantly alter its crystallization behaviour.

Characterization of bacterial coliform occurrences in different zones of a drinking water distribution system.

Aims: To compare the bacterial coliforms detected from occurrences in three zones of a water distribution system supplied by two separate water sources.

Methods And Results: Conventional and standardized protocols for identifying enterobacterial populations were applied. Additional tests to confirm isolates were included.

Use of a MS-electronic nose for prediction of early fungal spoilage of bakery products.

A MS-based electronic nose was used to detect fungal spoilage (measured as ergosterol concentration) in samples of bakery products. Bakery products were inoculated with different Eurotium, Aspergillus and Penicillium species, incubated in sealed vials and their headspace sampled after 2, 4 and 7 days. Once the headspace was sampled, ergosterol content was determined in each sample.

Vancomycin- and erythromycin-resistant enterococci in a pig farm and its environment.

A high prevalence of vancomycin- and erythromycin-resistant enterococci (VRE and ERE respectively) in a pig farm and its environment was observed. A similar structure and composition of enterococcal populations was detected between urban sewage and those associated with the pig environment. Enterococcus faecium was the most predominant species among VRE isolates from both animal and human origin.

Distribution and persistence of fecal bacterial populations in liquid and dewatered sludge from a biological treatment plant.

The changes in composition and structure of fecal coliforms (FC) and enterococci (ENT) populations, as well as the elimination of spores of sulphite-reducing bacteria (SRB), were compared between municipal sewage and their derived sludge in a biological treatment plant in order to determine any selective reduction or adsorption to sludge during the treatment process. Additionally, the persistence of antibiotic-resistant enterococcal populations in two kinds of sludge was also considered to evaluate their potential elimination in the treatment process. Microbial indicators, vancomycin-resistant and erythromycin-resistant enterococci were enumerated.

Occurrence and relatedness of vancomycin-resistant enterococci in animals, humans, and the environment in different European regions.

Vancomycin-resistant enterococci (VRE) in Europe are thought to have emerged partly due to the use of the glycopeptide avoparcin in animal husbandry. We compared the occurrence of VRE in geographical regions of Europe in which until 1997 large amounts of avoparcin were used (Spain, United Kingdom, and Denmark) with the occurrence of VRE in Sweden, where avoparcin was banned in 1986. We also studied the relatedness between VRE strains from different regions and habitats.

Early detection of fungal growth in bakery products by use of an electronic nose based on mass spectrometry.

This paper presents the design, optimization, and evaluation of a mass spectrometry-based electronic nose (MS e-nose) for early detection of unwanted fungal growth in bakery products. Seven fungal species (Aspergillus flavus, Aspergillus niger, Eurotium amstelodami, Eurotium herbariorum, Eurotium rubrum, Eurotium repens, and Penicillium corylophillum) were isolated from bakery products and used for the study. Two sampling headspace techniques were tested: static headspace (SH) and solid-phase microextraction (SPME).

The composition and persistence of faecal coliforms and enterococcal populations in sewage treatment plants.

Aims: The changes in structure and composition of faecal coliforms and enterococcal populations in sewage from different treatment plants, and the elimination of vancomycin- and erythromycin-resistant enterococci (VRE and ERE, respectively) in these treatment plants was analysed to determine any selective reduction.

Methods And Results: Faecal coliforms, enterococci, VRE, ERE and spores of sulphite-reducing bacteria were enumerated using standard methods. Samples were enriched where necessary in order to isolate antibiotic resistant strains.

Comparison of enterococcal populations in animals, humans, and the environment--a European study.

The objectives of the present study were to generate knowledge of enterococcal populations in the food chain, by studying the population structure (in measures of abundance and diversity) among enterococci in different geographical regions and in different parts of the food chain, as well as the similarities between different enterococcal populations. Altogether, 2868 samples were collected from humans (healthy and hospitalised individuals and clinical isolates), animals (slaughterhouse carcasses and farm animals), and the environment (pig farms, sewage, and surface water) in four European countries-Sweden, Denmark, UK, and Spain. The samples were characterised with regard to presence and numbers of enterococci, and eight (for faecal samples) or 24 (for environmental samples) isolates per sample were phenotyped and preliminarily identified with the PhP-RF system.

Comparison of enterococcal populations related to urban and hospital wastewater in various climatic and geographic European regions.

Aims: Scarce knowledge about the distribution of enterococci species in wastewaters limits any statement on their reliability as faecal indicators or the implications of antibiotic resistance transmission by these organisms through the water cycle. Enterococci have been involved in nosocomial infections and the spreading of antibiotic resistance through the food chain. The species distribution of enterococci and the presence of resistant strains to vancomycin and erythromycin were analysed in more than 400 raw and treated urban wastewaters, surface waters receiving these treated wastewaters and hospital wastewaters from three European countries.

Quantitative analysis of NO2 in the presence of CO using a single tungsten oxide semiconductor sensor and dynamic signal processing.

We demonstrate that NO2 can be quantitatively analysed in the presence of CO using a single tungsten oxide based resistive gas sensor. The working temperature of the sensor was modulated between 190 and 380 degrees C and its dynamic response to different concentrations of CO, NO2, and CO + NO2 mixtures was monitored. Either the fast Fourier transform (FFT) or the discrete wavelet transform (DWT) was used to extract important features from the sensor response.

Characterization of sewage waters by biochemical fingerprinting of Enterococci.

Three sewage waters with different sources of faecal pollution (human, pig and mixed origin) were analysed. Enumeration of Enterococci was performed and representative strains for each sample were isolated. Biochemical fingerprints of these strains were obtained by using a simple automated microplate system.