Nanostructured transition metal oxides (TMO) are extensively explored materials for non-enzymatic glucose sensors. TMOs such as Iron oxides( α-Fe2O3, γ-Fe2O3, Fe3O4, etc.), NiO, CuO, Cr2O3, etc. have been utilized as electrocatalysts for glucose determination. Tremendous efforts have been put into identifying the impact of different morphologies of these materials on the glucose-sensing performance. The larger surface area of the flower and wire-shaped catalysts make them better performing amongst other morphologies. Interestingly, it is important to note that most of such studies are on standard Glassy Carbon electrodes. Further to enhance the Electrochemically active surface area (ECSA) of the electrode, Carbon nanomaterials such as reduced Graphene Oxide (r-GO) and Carbon Nanotubes (CNTs) are used as additives. Exfoliated Graphite paper electrodes offer better electrochemical characteristics than GCE electrodes due to their much larger ECSA. This study presents the non-enzymatic glucose sensing properties of NiO nanoflower-decorated Exfoliated Graphite electrodes. The amperometric detection of glucose shows a linear increase in current over a physiologically relevant wide range
Microplastics (MPs) are ubiquitous in all ecosystems, affecting wildlife and, ultimately, human health. The complexity of natural samples plus the unspecificity of their treatments to isolate polymers renders the characterization of thousands of particles impractical for environmental monitoring using conventional spectroscopic techniques. Two primary solutions are to analyze a small fraction of the sample or to measure only a subset of particles present over a holder, known as subsampling. A strategy to subsample reflective Kevley slides and gold-coated filters using quantum-cascade laser-based infrared imaging is proposed here, as this technology is a promising tool for MPs monitoring. In contrast to most previous approaches that struggle to propose general subsampling schemes, we introduce the concept of sample-based subsampling. This can be applied ex-ante always and it highlights the best subsampling areas for a sample after a preliminary assay to count the total number of particles on a holder. The error at this stage acts as a proxy to minimize errors when evaluating the number of particles and MPs, significantly enhancing the feasibility of large-scale MPs monitoring. The p
A simple and fast radiochemical procedure for the sequential extraction of U, Np and Pu from small-volume seawater samples ($<10$ L) is presented. The method has been developed and optimized for the final determination of $^{236}$U, $^{237}$Np, $^{239}$Pu and $^{240}$Pu by Accelerator Mass Spectrometry (AMS). It is based on the use of $^{242}$Pu as tracer for both Np and Pu isotopes. Samples are pre-concentrated by Fe(OH)$_2$ co-precipitation. TEVA and UTEVA resins are used in a very simplified way for the final purification of the Pu+Np and U fractions, respectively. The radiochemical yields of the three elements have been investigated in detail by alpha spectrometry (AS) and gamma spectrometry (GS). The obtained results indicate high and robust chemical yields for the three elements and similar ones for Pu and Np. Furthermore, the use of $^{242}$Pu as tracer for $^{237}$Np is validated by analyzing a reference seawater sample (IAEA-443) by radiometric techniques. We demonstrated that, if chemicals are properly chosen, processed blank levels can be kept at the same level of the extremely low detection limits that can be achieved by AMS ($10^5 - 10^6$ atoms/sample). The procedur
In this work we present and evaluate a radiochemical procedure optimised for the analysis of $^{236}$U and $^{239,240}$Pu in seawater samples by Accelerator Mass Spectrometry (AMS). The method is based on Fe(OH)$_3$ co-precipitation of actinides and uses TEVA and UTEVA extraction chromatography resins in a simplified way for the final U and Pu purification. In order to improve the performance of the method, the radiochemical yields are analysed in 1 to 10 L seawater volumes using alpha spectrometry (AS) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Robust 80% plutonium recoveries are obtained; however, it is found that Fe(III) concentration in the precipitation solution and sample volume are the two critical and correlated parameters influencing the initial uranium extraction through Fe(OH)$_3$ co-precipitation. Therefore, we propose an expression that optimises the sample volume and Fe(III) amounts according to both the $^{236}$U and $^{239,240}$Pu concentrations in the samples and the performance parameters of the AMS facility. The method is validated for the current setup of the 1 MV AMS system (CNA, Sevilla, Spain), where He gas is used as a stripper, by analysing
Magnetic resonance microimaging (MR mu I) is an outstanding technique for studying water transfers in millimetric bio-based materials in a non-destructive and non-invasive manner. However, depending on the composition of the material, monitoring and quantification of these transfers can be very complex, and hence reliable image processing and analysis tools are necessary. In this study, a combination of MR mu I and multivariate curve resolution-alternating least squares (MCR-ALS) is proposed to monitor the water ingress into a potato starch extruded blend containing 20% glycerol that was shown to have interesting properties for biomedical, textile, and food applications. In this work, the main purpose of MCR is to provide spectral signatures and distribution maps of the components involved in the water uptake process that occurs over time with various kinetics. This approach allowed the description of the system evolution at a global (image) and a local (pixel) level, hence, permitted the resolution of two waterfronts, at two different times into the blend that could not be resolved by any other mathematical processing method usually used in magnetic resonance imaging (MRI). The re
Simple and low-cost biosensing solutions are suitable for point-of-care applications aiming to overcome the gap between scientific concepts and technological production. To compete with sensitivity and selectivity of golden standards, such as liquid chromatography, the functionalization of biosensors is continuously optimized to enhance the signal and improve their performance, often leading to complex chemical assay development. In this research, the efforts are made on optimizing the methodology for electrochemical reduction of graphene oxide to produce thin film-modified gold electrodes. Under the employed specific conditions, 20 cycles of cyclic voltammetry (CV) are shown to be optimal for superior electrical activation of graphene oxide into electrochemically reduced graphene oxide (ERGO). This platform is further used to develop a matrix metalloproteinase 2 (MMP-2) biosensor, where specific anti-MMP2 aptamers are utilized as a biorecognition element. MMP-2 is a protein which is typically overexpressed in tumor tissues, with important roles in tumor invasion, metastasis as well as in tumor angiogenesis. Based on impedimetric measurements, we were able to detect as low as 3.32
The tetanus neurotoxin (TeNT) is one of the most toxic proteins known to man, which prior to the use of the vaccine against the TeNT producing bacteria Clostridium tetani, resulted in a 20 % mortality rate upon infection. The clinical detrimental effects of tetanus have decreased immensely since the introduction of global vaccination programs, which depend on sustainable vaccine production. One of the major critical points in the manufacturing of these vaccines is the stable and reproducible production of high levels of toxin by the bacterial seed strains. In order to minimize time loss, the amount of TeNT is often monitored during and at the end of the bacterial culturing. The different methods that are currently available to assess the amount of TeNT in the bacterial medium suffer from variability, lack of sensitivity, and/or require specific antibodies. In accordance with the consistency approach and the three Rs (3Rs), both aiming to reduce the use of animals for testing, in-process monitoring of TeNT production could benefit from animal and antibody-free analytical tools. In this paper, we describe the development and validation of a new and reliable antibody free targeted LC-
Wavelength and intensity in the infrared are translated into colors in the visible
Scientists have created twisted laser beams that interact differently with right-handed and left-handed molecules, revealing their identity through the fragments they produce。 The approach could provide a faster, simpler, and more sensitive way to analyze important molecules used in chemistry and pharmaceuticals
Researchers have created cosmic dust from scratch by recreating space-like conditions inside glass tubes。 The dust contains complex carbon-rich molecules built from elements essential to life and produces infrared signals similar to real material found in space。 By studying these laboratory samples, scientists can explore how organic chemistry unfo
Dying Sun-like stars may not fade away quietly。 As blobs of gas erupt unevenly from their swollen surfaces, each burst gives the star a tiny push in the opposite direction。 Thousands of these random kicks could eventually break apart distant stellar pairs or, in rare cases, drive two stars into a violent collision
Engineers have transformed a notoriously brittle cobalt-aluminum compound into a material that is both extremely strong and capable of bending without breaking。 Their nanoscale design produced a yield strength about six to 10 times greater than high-strength structural steel while sustaining substantial deformation at room temperature。 The approach
A new analysis suggests the Sun holds far more silver than earlier estimates indicated。 More advanced models of the solar atmosphere raised the calculated amount by 55 percent, bringing it into much closer agreement with ancient meteorites。 The technique may also help scientists track the cosmic origins of silver and other heavy elements
Astronomers have found the first confirmed atmosphere around a rocky planet in another star’s habitable zone。 The planet, LHS 1140 b, revealed its atmosphere through helium slowly leaking into space。 Located 48 light-years away, the world may have preserved its atmosphere for billions of years, making it a promising target in the search for potenti
A giant planet had been hiding inside one of astronomy’s most closely studied planetary systems, concealed by a bright disk of cosmic dust。 Webb revealed Beta Pictoris d through atmospheric traces of carbon monoxide, water vapor, and methane, showcasing a promising new method for finding elusive exoplanets