Search Results (1,744)

With advances in technology, the generation of electrical energy through the harvesting of energies dissipated in the form of mechanical vibration, known as power harvesting, has received increasing attention in recent decades. It is undoubtedly an interesting means to power systems with low energy consumption. This research aims to evaluate an energy generation system based on the piezoelectric effect activated by mechanical excitation and develop a system capable of powering devices and sensors for temperature monitoring in a practical situation, such as in an engine room, aiming to ensure its safe operation. Two transducers subjected to vibrational excitation were evaluated, and then an energy generation system using a buck DC-DC converter circuit was assessed. The transducer was connected to the input of the board, the microcontroller to the output, and the LM35 temperature sensor along with the battery was used to ensure the circuit’s autonomy. Additionally, the Attiny85 microcontroller was programmed to perform temperature monitoring tasks in a continuous low-energy-consumption mode. The obtained spectral analysis results showed a maximum generation power of 8.88 mW for the PZT-5H transducer and 3.3 mW for the P5-13B transducer. The use of LTC3588-1 increased the autonomy of the monitoring system by 64.3% and reduced the system’s usage time in cases of temperature anomalies by 50%. Full article

The purpose of this research was to validate a urine sensor (Lincoln University PEETER V2.0, Canterbury, New Zealand) that records the time and volume of urination events for dairy cows in addition to collecting a proportional urine sample from all urination events. Sixteen multiparous Holstein × Jersey mid-lactating cows (101 ± 5 days in milk, 498 ± 24.2 kg body weight, 26.2 ± 3.07 kg/d milk yield; mean ± standard deviation) were allocated herbage diets ranging in protein and sodium content to generate a range of urine volumes and urine nitrogen (UN) concentrations. Total collection of individual urination events occurred during a 72-h measurement period where PEETER V2.0 sensors were attached to cows. A mixed model ANOVA using lme4 package (version 1.1-35.5) in R (version 4.3.3) were used to compare the means. The average urine event size was 2.65 ± 1.1 L for total collection by observers and 2.68 ± 1.1 L as recorded by the sensor (mean ± standard deviation; p = 0.730). The urine nitrogen concentration was 5.76 ± 1.2 g N/L for samples collected by observers and 5.85 ± 1.3 g N/L for the samples collected by the sensor (p = 0.583). The calculated UN excretion was 156 ± 45.1 g/day for direct measurements and 162 ± 40.0 g/day for the sensor (p = 0.539. Contrasts with simultaneously measured data were undertaken using Lin’s Concordance Correlation Coefficient (CCC) and a Pearson correlation coefficient (r). Correlations between the actual values and sensor values were strong, with little to moderate variability in the urine volume (CCC = 0.936, r = 0.937; n = 222), UN concentration (CCC = 0.840, r = 0.837, n = 48) and total UN excretion (CCC = 0.827, r = 0.836, n = 24). Considering the findings, the PEETER V2.0 urine sensor has the potential to reliably measure urine volumes and UN concentrations for estimations of the UN excretion of dairy cattle under grazing systems. Full article

Sprinkle formulations represent an interesting genre of medicinal products. A frequent problem, however, is the need to mask the unpleasant taste of these drug substances. In the present work, we propose the use of a novel sensor array based on solid-state ion-selective electrodes to evaluate the taste-masking efficiency of rosuvastatin (ROS) sprinkle formulations. Eight Multiple Unit Pellet Systems (MUPSs) were analyzed at two different doses (API_50) and (API_10), as well as pure Active Pharmaceutical Ingredient (API) as a bitter standard. Calcium phosphate-based starter pellets were coated with the mixture containing rosuvastatin. Some of them were additionally coated with hydroxypropyl methylcellulose, which was intended to separate the bitter substance and prevent it from coming into contact with the taste buds. The sensor array consisted of 16 prepared sensors with a polymer membrane that had a different selectivity towards rosuvastatin calcium. The main analytical parameters (sensitivity, selectivity, response time, pH dependence of potential, drift of potential, lifetime) of the constructed ion-selective electrodes sensitive for rosuvastatin were determined. The signals from the sensors array recorded during the experiments were processed using Principal Component Analysis (PCA). The results obtained, i.e., the chemical images of the pharmaceutical samples, indicated that the electronic tongue composed of the developed solid-state electrodes provided respective attributes as sensor signals, enabling both of various kinds of ROS pellets to be distinguished and their similarity to ROS bitterness standards to be tested. Full article

The rapid and sensitive detection of Salmonella typhimurium in food matrices is crucial for ensuring food safety. This study presents the development of an ultrasensitive electrochemical biosensor using surface-modified bacterial cellulose (BC) integrated with polypyrrole (Ppy) and reduced graphene oxide (RGO), further functionalized with immobilized S. typhimurium-specific phage particles. The BC substrate, with its ultra-fibrous and porous structure, was modified through in situ oxidative polymerization of Ppy and RGO, resulting in a highly conductive and flexible biointerface. The immobilization of phages onto this composite was facilitated by electrostatic interactions between the polycationic Ppy and the negatively charged phage capsid heads, optimizing phage orientation and enhancing bacterial capture efficiency. Morphological and chemical characterization confirmed the successful fabrication and phage immobilization. The biosensor demonstrated a detection limit of 1 CFU/mL for S. typhimurium in phosphate-buffered saline (PBS), with a linear detection range spanning 10⁰ to 10⁷ CFU/mL. In real samples, the sensor achieved detection limits of 5 CFU/mL in milk and 3 CFU/mL in chicken, with a linear detection range spanning 10⁰ to 10⁶ CFU/mL, maintaining high accuracy and reproducibility. The biosensor also effectively discriminated between live and dead bacterial cells, demonstrating its potential in real-world food safety applications. The biosensor performed excellently over a wide pH range (4–10) and remained stable for up to six weeks. Overall, the developed BC/Ppy/RGO–phage biosensor offers a promising tool for the rapid, sensitive, and selective detection of S. typhimurium, with robust performance across different food matrices. Full article

The synthesis and characterization of iron oxide nanostructures, specifically snowflake architecture, are investigated for their potential applications in electrochemical sensing systems. A Raman spectroscopy analysis reveals phase diversity in the synthesized powders. The pH of the synthesis affects the formation of the hematite (α-Fe₂O₃) and goethite (α-FeOOH). Scanning electron microscopy (SEM) images confirm the distinct morphologies of the particles, which are selectively obtained through recrystallization during the elongated reaction time. An electrochemical analysis demonstrates the differing behaviors of the particles, with synthesis pH affecting the electrochemical activity and surface area differently for each shape. Cyclic voltammetry measurements reveal reversible dopamine detection processes, with snowflake iron oxide showing lower detection limits than a mixture of snowflakes and cube-like particles. This research contributes to understanding the relationship between iron oxide nanomaterials’ structural, morphological, and electrochemical properties. It offers practical insights into their potential applications in sensor technology, particularly dopamine detection, with implications for biomedical and environmental monitoring. Full article

The research introduces a revolutionary Internet of Things (IoT)-based system for fish farming, designed to significantly enhance efficiency and cost-effectiveness. By integrating the NodeMcu12E ESP8266 microcontroller, this system automates the management of critical water quality parameters such as pH, temperature, and oxygen levels, essential for fostering optimal fish growth conditions and minimizing mortality rates. The core of this innovation lies in its intelligent monitoring and control mechanism, which not only supports accelerated fish development but also ensures the robustness of the farming process through automated adjustments whenever the monitored parameters deviate from desired thresholds. This smart fish farming solution features an Arduino IoT cloud-based framework, offering a user-friendly web interface that enables fish farmers to remotely monitor and manage their operations from any global location. This aspect of the system emphasizes the importance of efficient information management and the transformation of sensor data into actionable insights, thereby reducing the need for constant human oversight and significantly increasing operational reliability. The autonomous functionality of the system is a key highlight, designed to persist in adjusting the environmental conditions within the fish farm until the optimal parameters are restored. This capability greatly diminishes the risks associated with manual monitoring and adjustments, allowing even those with limited expertise in aquaculture to achieve high levels of production efficiency and sustainability. By leveraging data-driven technologies and IoT innovations, this study not only addresses the immediate needs of the fish farming industry but also contributes to solving the broader global challenge of protein production. It presents a scalable and accessible approach to modern aquaculture, empowering stakeholders to maximize output and minimize risks associated with fish farming, thereby paving the way for a more sustainable and efficient future in the global food supply. Full article

Wearable tear-based biosensors have garnered substantial interest for real time monitoring with an emphasis on personalized health care. These biosensors utilize major tear biomarkers such as proteins, lipids, metabolites, and electrolytes for the detection and recording of stable biological signals in a non-invasive manner. The present comprehensive review delves deep into the tear composition along with potential biomarkers that can identify, monitor, and predict certain ocular diseases such as dry eye disease, conjunctivitis, eye-related infections, as well as diabetes mellitus. Recent technologies in tear-based wearable point-of-care medical devices, specifically the state-of-the-art and prospects of glucose, pH, lactate, protein, lipid, and electrolyte sensing from tear are discussed. Finally, the review addresses the existing challenges associated with the widespread application of tear-based sensors, which will pave the way for advanced scientific research and development of such non-invasive health monitoring devices. Full article

Various rapid propagation strategies have been discovered, which has facilitated large-scale plant reproduction and cultivar development. These methods, in many plant species, are used to rapidly generate large quantities (900 mini-tubers/m²) of high-quality propagule (free from contamination) at a relatively low cost in a small space. They are also used for plant preservation. This review article aims to provide potential applications for regeneration and clonal propagation. Plant propagation using advanced agrotechnology, such as aeroponics, is becoming increasingly popular among academics and industrialists. The advancement of asexual aeroponic propagation has been achieved through advancements in monitoring and control systems using IoT and smart sensor technology. New sensor technology systems have gained substantial interest in agriculture in recent years. It is used in agriculture to precisely arrange various operations and objectives while harnessing limited resources with minimal human intervention. Modern intelligent technologies and control systems simplify sensor data collection, making it more efficient than manual data collection, which can be slow and prone to errors. Specific ambient variables like temperature, humidity, light intensity, stock solution concentrations (nutrient water), EC (electrical conductivity), pH values, CO₂ content, and atomization parameters (frequency and interval) are collected more effectively through these systems. The use of intelligent technologies provides complete control over the system. When combined with IoT, it aids in boosting crop quality and yield while also lowering production costs and providing data directly to tablets and smartphones in aeroponic propagation systems. It can potentially increase the system’s productivity and usefulness compared to the older manual monitoring and operating methods. Full article

Pure tin oxide (SnO₂) as a typical conductometric hydrogen sulfide (H₂S) gas-sensing material always suffers from limited sensitivity, elevated operation temperature, and poor selectivity. To overcome these hindrances, in this work, hollow CuO-SnO₂ nanotubes were successfully electrospun for room-temperature (25 °C) trace H₂S detection under blue light activation. Among all SnO₂-based candidates, a pure SnO₂ sensor showed no signal, even toward 10 ppm, while the 1% CuO-SnO₂ sensor achieved a limit of detection (LoD) value of 2.5 ppm, a large response of 4.7, and a short response/recovery time of 21/61 s toward 10 ppm H₂S, as well as nice repeatability, long-term stability, and selectivity. This excellent performance could be ascribed to the one-dimensional (1D) hollow nanostructure, abundant p-n heterojunctions, and the photoelectric effect of the CuO-SnO₂ nanotubes. The proposed design strategies cater to the demanding requirements of high sensitivity and low power consumption in future application scenarios such as Internet of Things and smart optoelectronic systems. Full article

A simple, sensitive and reliable sensing system based on nitrogen-rich porous carbon (NRPC) and transition metals, NRPC/Ni, NRPC/Mn and NRPC/NiMn was developed and successfully applied as electrode materials for the quantitative determination of carbendazim (CBZ). The synergistic effect of NRPC and bimetals with acceptable pore structure together with flower-like morphology resulted in producing a highly conductive and interconnected network in NRPC/NiMn@GCE, which significantly enhanced the detection performance of CBZ. The electrochemical behavior investigated by cyclic voltammetry (CV) showed improved CBZ detection for NRPC/NiMn, due to the controlled adsorption/diffusion process of CBZ by the NRPC/NiMn@GCE electrode. The influences of various factors such as pH, NRPC/NiMn concentration, CBZ concentration and scan rate were studied. Under optimal conditions, 0.1 M phosphate-buffered saline (PBS) with a pH of 7.0 containing 30 µg/mL NRPC/NiMn, a favourable linear range detection of CBZ from 5 to 50 µM was obtained. Moreover, a chronoamperometric analysis showed excellent repeatability, reproducibility and anti-interfering ability of the fabricated NRPC/NiMn@GCE sensor. Furthermore, the sensor showed satisfactory results for CBZ detection in real samples with acceptable recoveries of 96.40–104.98% and low RSD values of 0.25–3.45%. Full article

Urine analysis represents a crucial diagnostic technique employed in clinical laboratories. Creatinine and uric acid in urine are essential biomarkers in the human body and are widely utilized in clinical analysis. Research has demonstrated a correlation between the normal physiological concentrations of creatinine and uric acid in urine and an increased risk of hypertension, cardiovascular diseases, and kidney disease. Furthermore, the pH of urine indicates the body’s metabolic processes and homeostatic balance. In this study, an integrated multi-channel electrochemical sensing system was developed, combining electrochemical analysis techniques, microelectronic design, and nanomaterials. The architecture of an intelligent medical detection system and the production of an interactive interface for smartphones were accomplished. Initially, multi-channel selective electrodes were designed for creatinine, uric acid, and pH detection. The detection range was 10 nM to 100 μM for creatinine, 100 μM to 500 μM for uric acid, and 4 to 9 for pH. Furthermore, interference experiments were also conducted to verify the specificity of the sensors. Subsequently, multi-channel double-sided sensing electrodes and function-integrated hardware were designed, with the standard equations of target analytes stored in the system’s read-only memory. Moreover, a WeChat mini-program platform was developed for smartphone interaction, enabling off-body detection and real-time display of target analytes through smartphones. Finally, the aforementioned electrochemical detection electrodes were integrated with the smart sensing system and wirelessly interfaced with smartphones, allowing for intelligent real-time detection in primary healthcare and individual household settings. Full article

Conducting polymers used in chemical sensors are attractive because of their ability to confer reversible properties controlled by the doping/de-doping process. Polyaniline (PANI) is one of the most prominent materials used due to its ease of synthesis, tailored properties, and higher stability. Here, PANI thin films deposited by the drop-casting method on fluorine-doped tin oxide (FTO) substrates were used in electrochemical and optical sensors for pH measurement. The response of the devices was correlated with the deposition parameters; namely, the volume of deposition solution dropped on the substrate and the concentration of the solution, which was determined by the weight ratio of polymer to solvent. The characterisation of the samples aimed to determine the structure–property relationship of the films and showed that the chemical properties, oxidation states, and protonation level are similar for all samples, as concluded from the cyclic voltammetry and UV–VIS spectroscopic analysis. The sensing performance of the PANI film is correlated with its relative physical properties, thickness, and surface roughness. The highest electrochemical sensitivity obtained was 127.3 ± 6.2 mV/pH, twice the Nernst limit—the highest pH sensitivity reported to our knowledge—from the thicker and rougher sample. The highest optical sensitivity, 0.45 ± 0.05 1/pH, was obtained from a less rough sample, which is desirable as it reduces light scattering and sample oxidation. The results presented demonstrate the importance of understanding the structure–property relationship of materials for optimised sensors and their potential applications where high-sensitivity pH measurement is required. Full article

Dissolved gas analysis (DGA) is a vital method for the online detection of transformer operation state. The adsorption performance of a SnP₃ monolayer modified by transition metal Cr regarding six characteristic gases (CO, C₂H₄, C₂H₂, CH₄, H₂, C₂H₆) dissolved in oil was studied. The study reveals the relevant adsorption and gas-sensing response mechanisms through calculations of the adsorption energy, density of states, differential charge density, energy gap, and recovery time. The results display a considerable increase in the adsorption effect of the Cr-SnP₃ monolayer on six gases. The CO, C₂H₂, and C₂H₄ gases lead to chemical adsorption, and the CH₄, H₂, and C₂H₆ gases lead to physical adsorption. Combined with the recovery time, the Cr-SnP₃ monolayer has a strong adsorption effect on CO and C₂H₂ gases at normal temperatures and even high temperatures, and the adsorption is stable. C₂H₄ gas can be rapidly desorbed from the Cr-SnP₃ monolayer at 398 K. Therefore, the Cr-SnP₃ monolayer can be expected to serve as a CO and C₂H₂ gas adsorbent and a resistive gas sensor for C₂H₄ gas. This research offers a theoretical foundation for the development of the Cr-SnP₃ monolayer in gas-sensitive materials. Full article

A new molecularly imprinted polymer (MIP)-based disposable electrochemical sensor for dipyridamole (DIP) determination was obtained. The sensor was rapidly prepared by potentiodynamic electrochemical polymerization on a pencil graphite electrode (PGE) using curcumin (CUR) as a functional monomer and DIP as a template molecule. After the optimization of the conditions (pH, monomer–template ratio, scan rate, number of cyclic voltammetric cycles applied in the electro-polymerization process and extraction time of the template molecule) for MIP formation, DIP voltammetric behavior at the modified electrode (MIP_PGE) was investigated. DIP oxidation took place in a pH-dependent, irreversible mixed diffusion-adsorption controlled process. Differential pulse voltammetry (DPV) and adsorptive stripping differential pulse voltammetry (AdSDPV) were used to quantify DIP from pharmaceutical and tap water samples. Under optimized conditions (Britton–Robinson buffer at pH = 3.29), the obtained linear ranges were 5.00 × 10⁻⁸–1.00 × 10⁻⁵ mol/L and 5.00 × 10⁻⁹–1.00 × 10⁻⁷ mol/L DIP for DPV and AdSDPV, respectively. The limits of detection of the methods were 1.47 × 10⁻⁸ mol/L for DPV and 3.96 × 10⁻⁹ mol/L DIP for AdSDPV. Full article

In the present study, we demonstrated that the introduction of a 1,4-diethyl-1,2,3,4-tetrahydroquinoxalin moiety into the arylidene part of GFP chromophore-derived compounds results in the formation of environment-sensitive fluorogens. The rationally designed and synthesized compounds exhibit remarkable solvent- and pH-dependence in fluorescence intensity. The solvent-dependent variation in fluorescence quantum yield makes it possible to use some of the proposed compounds as polarity sensors suitable for selective endoplasmic reticulum fluorescent labeling in living cells. Moreover, the pH-dependent emission intensity variation of other fluorogens makes them selective fluorescent labels for the lysosomes in living cells. Full article