Lower Limit Research Articles

Wheatstone Bridge MEMS Hydrogen Sensor with ppb-Level Detection Limit Based on the Palladium-Gold Alloy.

On some occasions, such as new energy clinics, monitoring the trace hydrogen at the ppb level is necessary. The traditional resistive hydrogen sensors based on the Pd alloys are very difficult to realize such an extremely low detection limit. To achieve a detection limit at the ppb level and also ensure good stability, a MEMS hydrogen sensor was designed in a suspended Wheatstone bridge structure, with all four resistive arms defined on a sputtered Pd-Au alloy thin film. For the Wheatstone bridge sensor, absolute response (Ra) and relative response (Rs) are defined to describe the sensitivity of the sensor, and the effect of annealing temperature on baseline drift is investigated using the baseline zero drift parameter (DBZD). By testing the sensors across a hydrogen concentration range of 20 ppb to 3 v/v%, the optimal annealing temperature (250 °C) and operating temperature (60 °C) were identified. Under these conditions, the sensor exhibited a detection limit as low as 20 ppb with a power consumption of only 4.6 mW. At the same time, the response and recovery times of the sensor were 6 and 19 s, respectively, toward 3 v/v% hydrogen. After testing over a 100-day period, Ra fluctuated only 0.0026%, indicating that the hydrogen sensor had good long-term stability for low-concentration detection. More results also showed that the sensor has good repeatability, selectivity, and humidity resistance. With the wide measurement range (20 ppb to 3 v/v%), the sensor has the potential to meet hydrogen detection requirements in multiple scenarios.

Adenine-originated N-doped C3N4 modified glassy carbon electrode for ultra-sensitive electrochemical quantification of cysteamine drug

Cystinosis is a rare autosomal recessive illness in which cystine accumulates in lysosomes, causing crystallisation in important organs. Cysteamine, the only approved therapy, demands precise concentration control because of its therapeutic importance. Cysteamine detection methods, including fluorescence spectroscopy, chemical etching, and HPLC, need sophisticated sample preparation and expensive equipment. Electrochemical sensing provides a simpler alternative with higher sensitivity and selectivity. However, traditional carbon electrodes have limited sensitivity and detection limits. Nitrogen (N-CN), sulfur (S-CN), and nitrogen/sulfur co-doped (N, S-CN) graphitic carbon nitride materials were produced using a one-pot calcination of adenine and methionine precursors. N-CN-modified glassy carbon electrodes demonstrated higher electrocatalytic activity, quicker electron transfer, and increased selectivity, sensitivity, and stability for cysteamine detection. Structural and morphological characterisation of the synthesised materials was performed using various analytical techniques, including Fourier-transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, Brunauer-Emmett-Teller plots, X-ray diffraction, and X-ray photoelectron spectroscopy. The sensor showed a linear relationship between anodic peak current and cysteamine concentration in the range of 0 µM to 1 mM, with a low detection limit of 82.5 nM (0.0825 µM). Moreover, the modified electrode exhibited good reproducibility and stability with a recovery rate of 95.5 % and a relative standard deviation (RSD < 5 %). Real-sample analysis revealed a good agreement between LSV and HPLC for detecting cysteamine in blood serum. The paper describes a unique metal-free N-CN synthesis utilising adenine, allowing effective electrochemical detection.

Photonic sensor based on surface imprinted polymers for enhanced point-of-care diagnosis of bacterial urinary tract infections

Effective bacterial detection is crucial for health diagnostics, particularly for the detection of pathogenic species like Escherichia coli (E. coli), which is responsible for up to 90% of urinary tract infections (UTIs), is especially crucial. Current detection methods are time-consuming, often delaying diagnosis and treatment. This study introduces an innovative approach for rapid E. coli detection using porous silicon (PSi) substrates combined with Surface Imprinted Polymers (SIPs) for photoluminescence-based (PL-based) E. coli detection. The PSi/SIP substrates offer high sensitivity, selectivity, and a low limit of detection (LOD) without the need for natural recognition elements. These substrates, fabricated via metal-assisted chemical etching (MACE) and PDMS-based E. coli imprinting, demonstrate reliable repeatability and a fast detection. Real-time detection experiments in phosphate-buffered saline (PBS) and urine showed consistent stair-like quenching of the PL signal with increasing E. coli concentrations, achieving theoretical LODs of approximately 13 ± 2 CFU/mL in PBS and 17 ± 3 CFU/mL in urine. The substrates exhibited excellent selectivity, differentiating E. coli from other species such as Cronobacter sakazakii (C. sakazakii) and Listeria monocytogenes. The high sensitivity and reproducibility of PSi/SIP substrates, along with the ease of use and rapid detection capabilities of the resulting sensor, highlight the potential of this novel platform for point-of-care (PoC) applications in clinical diagnostics.

A Smartphone-Enabled Colorimetric Microneedle Sensing Platform for Rapid Detection of Ascorbic Acid in Fruits.

Achieving rapid extraction and detection of analytical solutions from plant tissues to circumvent cumbersome procedures and reduce the dependence on detection instruments remains a challenge. Herein, a colorimetric microneedle integrated platform was developed for the rapid extraction and detection of plant fluids for testing purposes. Colorimetric microneedle patches (CMPs) offer a swift and effective method to swiftly extract and detect ascorbic acid (AA) within 10 min from various fruit crops like mango, nectarine, apple, pear, and kiwifruit, facilitated by a smartphone application. CMPs are constructed for the rapid and sensitive analysis of AA with good linearity amid the range 0.05-25 μM and a low limit of detection of 30 nM. The novel CMPs demonstrate significant potential as a rapid detection platform for AA in plants. CMPs offer significant advantages over traditional ultraviolet spectrophotometry, such as simplified operational procedures and accelerated extraction and detection processes. This establishes robust groundwork for conducting in situ extraction and molecular detection of diverse crops across a spectrum of application scenarios.

Real-time monitoring of aqueous total N-nitrosamines by UV photolysis and chemiluminescence.

N-nitrosamines such as N-nitrosodimethylamine (NDMA), N-nitrosodiethylamine (NDEA), N-nitrosopiperidine (NPIP), and N-nitrosopyrrolidine (NPYR) have been established as potent carcinogens that can induce diverse types of cancer. Several studies have extensively investigated the accurate quantification of total N-nitrosamines (TONO) and the intricate nature of the matrix in which they are detected. The potential for the formation of N-nitrosamines in post-combustion CO2 capture (PCCC) and water treatment has raised concerns. This study outlines a unique method for the quantification of TONO in aqueous matrices using UV photolysis and the subsequent detection of NO by chemiluminescence. This method offers benefits such as operation in the continuous mode and handling of high sample flow rates to achieve a low limit of detection (LOD) and a low limit of quantification (LOQ). The observed LODs for the individual N-nitrosamines of NDMA, N-nitrosomorpholine (NMOR), N-nitrosodibutylamine (NDBA), and NPIP range between 0.06 and 0.2µM at a sample flow rate of 0.25mL/min, while the LOD range is reduced to between 0.02 and 0.06µM at 0.75mL/min. Linear responses for the NO produced from specific N-nitrosamines are observed between 0.5 and 10µM. The developed method is resistant to interfering chemicals (i.e., nitrite, amines, and carbonyls) and exhibits high specificity.

Investigation of impact of community environment factors on the residents’ visiting rate to outdoor venues in South China

Understanding the activity patterns of urban residents is crucial for urban community design and urban energy forecasting. Predicting the visitation rates of different types of locations is a important issue because urban residents can only be in one place at a time. Achieving accurate predictions of outdoor public space visitation rates is equivalent to predicting the upper limit of the number of visitors to other buildings. Previous similar studies usually rely on survey methods such as questionnaires and GPS positioning. These methods have some drawbacks, such as small sample sizes and inaccurate data. In this paper, we used mobile signaling to investigate the park visit rates of residents in different communities in Guangzhou. In accordance with Chinese tradition, we define a community as a residential community, which consists of multiple residential units and a set of basic service facilities and management structures that are sufficient to meet the daily needs of residents. We found that the park visit rate of a community is closely related to the characteristics of the community itself. The park visit rate is positively correlated with the average LST (land surface temperature) of the communities, the average distance between the community and the large park, and the building coverage rate, while it is negatively correlated with the vegetation coverage rate, the average surface reflection rate, the convenience of transportation, and the per capita green space area. Given the different travel habits of urban residents on weekdays and weekends, we also used multiple linear regression to establish prediction models for community park visitation rates on weekdays and weekends.

Estimation of the Chances to Find New Phenomena at the LHC in a Model-Agnostic Combinatorial Analysis

In this paper, we estimate the number of event topologies that have the potential to be produced in pp collisions at the Large Hadron Collider (LHC) without violating kinematic and other constraints. We use numerical calculations and combinatorics, guided by large-scale Monte Carlo simulations of Standard Model (SM) processes. Then, we set the upper limit on the probability that new physics may escape detection, assuming a model-agnostic approach. The calculated probability is unexpectedly large, and the fact that LHC has not found new physics until now is not entirely surprising. Theoretical limitations and experimental challenges in observing new physics within the studied exclusive event classes are examined.

Polyvinyl fluoride: Predicting polarization in a complex soft matter system

We use first-principle density functional theory (DFT) to predict properties for semicrystalline polyvinyl fluoride (PVF) and compare with polyvinylidiene fluoride. We note that the crystalline regions of PVF are complex in the sense that we lack a complete experimental characterization of the detailed atomic organization. We therefore turn to DFT to predict both the structure and associated materials properties, illustrating a possible work flow for complex soft-matter modeling. We rely on the nonempirical consistent-exchange van der Waals density functional version [K. Berland and P. Hyldgaard, ] and identify plausible ground-state and excited-state motifs. From there we predict the elastic response of the crystalline motifs, and an upper limit estimate of the PVF polarization at room temperature. Published by the American Physical Society 2024

Ammonium hydrosulfide (NH_4SH) as a potentially significant sulfur sink in interstellar ices

Sulfur is depleted with respect to its cosmic standard abundance in dense star-forming regions. It has been suggested that this depletion is caused by the freeze-out of sulfur on interstellar dust grains, but the observed abundances and upper limits of sulfur-bearing ices remain too low to account for all of the missing sulfur. Toward the same environments, a strong absorption feature at sim 6.85 mu m is observed, but its long-standing assignment to the NH$_ $ cation remains tentative. We aim to spectroscopically investigate the plausibility of NH$_ $SH salt serving as a sulfur reservoir and a carrier of the 6.85 mu m band in interstellar ices by characterizing its IR signatures and apparent band strengths in water-rich laboratory ice mixtures. We then use this laboratory data to constrain NH$_ $SH abundances in observations of interstellar ices. Laboratory transmission IR spectra of NH$_ $:H$_ $S ice mixtures both with and without H$_ $O were collected. The apparent band strengths of the NH$_ $ asymmetric bending ($ $) mode and the SH$^ $ stretching mode in H$_ $O-containing mixtures were calculated with Beer's law plots. The IR features of the laboratory salts were compared to those observed toward a sample of four protostars (two low-mass, two high-mass) and two cold dense clouds without star formation. Apparent band strengths ranging from 3.2(pm 0.3)-3.6(pm 0.4)times 10$^ $ cm molec$^ $ and 3.1(pm 0.4)-3.7(pm 0.5)times 10$^ $ cm molec$^ $ are calculated for the NH$_ $ mode at sim 6.8 mu m/1470 cm$^ $ and the SH$^ $ stretching mode at sim 3.9 mu m/2560 cm$^ $, respectively, in NH$_ $SH:H$_ $O mixtures. The peak position of the NH$_ $ mode redshifts with increasing temperature but also with increasing salt concentration with respect to matrix species H$_ $O and NH$_ $. The observed 6.85 mu m feature is fit well with the laboratory NH$_ $SH:H$_ $O ice spectra. NH$_ $ column densities obtained from the 6.85 mu m band range from 8-23&lt;!PCT!&gt; with respect to H$_ $O toward the sample of protostars and dense clouds. These column densities are consistent with the optical depths observed at 3.9 mu m (the SH$^ $ stretching mode spectral region). A weak and broad feature observed at sim 5.3 mu m/1890 cm$^ $ is tentatively assigned to the combination mode of the NH$_ $ mode and the SH$^ $ libration. The combined upper limits of four other counter-anion candidates, OCN$^ $, CN$^ $, HCOO$^ $, and Cl$^ $, are determined to be lesssim 15-20&lt;!PCT!&gt; of the total NH$_ $ column densities toward three of the protostars. The redshift of the 6.85 mu m feature correlates with higher abundances of NH$_ $ with respect to H$_ $O in both the laboratory data presented here and observational data of dense clouds and protostars. The apparent band strength of the SH$^ $ feature is likely too low for the feature to be detectable in the spectrally busy 3.9 mu m region, but the 5.3 mu m NH$_ $ + SH$^ $ R combination mode may be an alternative means of detection. Its tentative assignment adds to mounting evidence supporting the presence of NH$_ $ salts in ices and is the first tentative observation of the SH$^ $ anion toward interstellar ices. If the majority (gtrsim 80-85&lt;!PCT!&gt;) of the NH$_ $ cations quantified toward the investigated sources in this work are bound to SH$^ $ anions, then NH$_ $SH salts could account for up to 17-18&lt;!PCT!&gt; of their sulfur budgets.

Microstructure Evolution and Mechanical Properties of Ta-Cladded Ni-Cr-Mo Low Alloyed Steel via Explosive Welding

The effects of welding variables (stand-off distance and explosive thickness) on the interfacial microstructure evolution and mechanical properties of explosively welded Ta alloy to Ni-Cr-Mo low alloyed steel have been investigated. Regardless of welding conditions (a stand-off distance of 3-5 mm and explosive thickness of 40-80 mm), the Ta/steel interface consistently exhibited a wavy configuration. This wavy interface facilitated the formation of vortex, resulting in strong interlocking. The height of the vortex increased with a larger stand-off distance at a fixed explosive thickness of 60 mm. Similarly, increasing the explosive thickness at a stand-off distance of 3 mm also resulted in a greater vortex height. The explosive weldability window, plotting the collision angle (β) against the collision point velocity (vc), was successfully established for the dissimilar Ta and steel plates. The upper limit prediction with N=0.11, as proposed by Wittman, best matched the experimental results. This guided the determination of the optimal condition, which was a standoff distance of 3 mm and an explosive thickness of 40 mm. A vortex melted zone (VMZ) was identified, which resulted from the dynamic intermixing of Ta and steel, combined with localized melting caused by high-energy collisions and heat accumulation. The VMZ surrounded by a highly deformed Ta alloy, showed the highest hardness. Near the interface on the steel side, a fine recrystallized grain structure was observed. No significant inter-diffusion was detected at the wavy Ta/steel interface. The tension-shear properties of the wavy interface, which was subjected to loading parallel to interface, showed a good balance of strength and ductility, confirming the soundness of Ta/steel interface.

Zoysia spp. putting green tolerance to postemergence herbicides

AbstractSpecies of Zoysia Willd. are used on approximately 9550 ha of golf course surfaces throughout the United States, primarily fairways and tees in transitional climates. Recently, cultivars featuring dwarf canopy height and improved quality have been released for putting green use; however, tolerance of these cultivars to postemergence herbicides is unknown. Field research was conducted in 2021 and 2022 evaluating the tolerance of Prizm® [Zoysia matrella (L.) Merr.] and Lazer® [Z. matrella (L.) Merr. × Zoysia minima (Colenso) Zotov] zoysiagrass to pyrimisulfan + penoxsulam (Aethon™), pyrimisulfan (Arkon™), flazasulfuron (Katana®), 2,4‐D + quinclorac + dicamba + sulfentrazone (Q4® Plus), 2,4‐D + MCPP + dicamba + carfentrazone (SpeedZone® EW), 2,4‐D + MCPP + dicamba + sulfentrazone (Surge®), and pyrimisulfan (formulated as a granule; Vexis®). A nontreated check was included for comparison. All of these herbicides have commercial labeling for use on zoysiagrass (Zoysia Willd.); however, none of these herbicides have labeling for use on zoysiagrass putting greens. Application rates in this study exceeded label maximums (for use on zoysiagrass) to ascertain the upper limits of Prizm® and Lazer® tolerance to these herbicides in Knoxville, TN and College Station, TX, respectively. Plots were arranged in randomized complete block design with four replications at both sites. Turfgrass injury was visually evaluated with data subjected to analysis of variance. Prizm® in Tennessee exhibited commercially acceptable tolerance to the applied herbicides, resulting in ≤8% injury either year. Lazer® in Texas sustained injury ranging from 21% to 61% and 10% to 31% in 2021 and 2022, respectively. Conditions of extreme heat and drought in Texas may have exacerbated differences in Lazer® tolerance to applied herbicides between years. Additional research across varying geographies and environmental conditions is needed to better understand tolerance of new zoysiagrass putting green lines, particularly within Z. minima.

Monetary work-incentives within the Austrian tax and benefit system

AbstractThis paper analyses incentives to take up work or to increase working hours within the Austrian tax and benefit system. We analyze the monetary work incentives for a variety of family constellations (singles, single parents, families with children) with different incomes from dependent employment, when receiving unemployment benefits, and in the system of means-tested minimum income. Moreover, the effect of different earning ceilings (childcare and unemployment) and childcare costs is additionally investigated. Insufficient and, therefore, privately provided childcare is viewed as a missing component of the benefit system. The Austrian tax and benefit system is designed to be incentive-compatible for singles. Only marginal employment without deductions in the event of unemployment creates a negative incentive to expand employment beyond this extent. However, raising children creates negative monetary incentives. On the one hand, through the upper limits on additional earnings during times of childcare allowance, but especially when childcare costs arise.

Limits to dynamic range in GHz-THz single-dish planetary spectra

Abstract When bright solar-system objects are observed by GHz-THz regime telescopes, off-axis signals bounce around locally and re-enter the signal path with a time delay, causing sinusoidal ripples in output spectra. Ripples that are unstable over time are challenging to remove. A typical detection limit for planetary spectral lines is a fraction ∼10−3 of continuum signal, restricting searches for minor atmospheric trace-gases. Modern wideband spectra of Venus demonstrate a plethora of effects, at three example telescopes spanning nearly a factor-of-50 in frequency. Characterisation of instrumental effects as families of pure sine-waves via Fourier-analysis is shown to improve dynamic-range by factors of a few. An example upper limit on sulphuric acid (H2SO4) vapour in Venus’ mesosphere, from fully-automated data-cleaning of a 3.5 GHz band containing 10 line components, goes as deep as the best previously-published limit. The most challenging cases are searches for single lines of width comparable to ripple periods. Traditional polynomial-fitting approaches can be deployed to test for false positives, to demonstrate robustness at a level of zero ”fake lines” in &amp;gt;1000 comparisons. Fourier-based data-cleaning avoids subjectivity and can be fully automated, and synthetic spectra can be injected before processing to test to what degree signals are lost in cleaning. An ideal robustness strategy is mitigation at the data-acquisition stage, e.g. using slow drifts in target-velocity with respect to the telescope to isolate a planetary line from a quasi-static instrumental ripple pattern.

Highly efficient electrocatalysts of NiMoO4 doped CdO nanostructure interconnected with modified glassy carbon electrode for the detection of chloramphenicol

In this study, we developed an excellent electrocatalyst of NiMoO4 doped with CdO and then coated electrochemical detection of chloramphenicol (CAP) via a glassy carbon electrode (NiMoO4@CdO/GCE). In particular, this drug treats typhoid, fever, and salmonellosis infections. CAP detection and measurements have become progressively important in ensuring human safety. The NiMoO4@CdO nanocomposite was prepared using the one-step hydrothermal method and characterized for its structural and optical properties. The electrochemical determination of CAP was investigated using cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS) techniques. We observed that the glassy carbon electrode modified with NiMoO4@CdO efficiently reduced the CAP at a very low potential. While CAP interacts with this system, metal oxide nanocomposites can combine with CAP reduction to produce phenylhydroxylamine. According to the DPV analysis, the bare electrode provides a linear response in the 10–100 µM range and a substantial reduction in CAP over a low detection limit of 0.083 µM when compared to (NiMoO4@CdO/GCE). Other co-existing molecules challenge the utility of this sensor. Additionally, this sensor exhibited high selectivity, stability, and reproducibility. Further, we evaluated the sensor for real-sample analysis, and the results were satisfactory.

Asymmetric CRISPR-Cas12a powered electrochemical aptasensor for clenbuterol detection based on competitive gRNA mediated cascade signal amplification

The residue of clenbuterol (CLB) in food poses a potential harm to human health. Herein, we presented an electrochemical aptasensor (E-A-CRISPR) based on employing an aptamer as a specific recognition element and asymmetric CRISPR-Cas12a as signal amplifiers for sensitive, and selective detection of CLB. In this E-A-CRISPR system, the target CLB bound to the aptamer and initiated cascade signal amplification through the DNase activity of CRISPR-Cas12a with two competitive gRNAs. Upon amplification, the active Cas12a cleaved the methylene blue-labeled hairpin probe on the electrode, reducing the peak current. Under optimal conditions, the E-A-CRISPR system showed a wide linear range (1 pM-100 nM) and a low detection limit (500 fM). This system could detect CLB in potable water, pig liver, and pork samples, showing significant potential for food safety monitoring. To our knowledge, this study is the first to use a CRISPR-Cas12a powered system for electrochemical sensing of CLB.

Influence of carbon dots as modifier and SiO2 shell coating as a protecting layer in YAlO3:Cr3+ phosphors for multimodal applications

This study focuses on the synthesis of SiO2-coated carbon dots (CDs) grafted onto YAlO3:Cr3+ (YAP:Cr3+) nanophosphors (NPs) through a combustion method. The CDs enhance the absorption cross-section of Cr3+ ions, significantly boosting the luminescence of YAP:Cr3+ by 19.29-fold. Further improvement is achieved with a SiO2 coating, leading to a 48.73-fold increase in photoluminescence intensity. The NCs are colour tunable, with emissions ranging from pinkish-red to blue, depending on the concentration of CDs and the excitation wavelength. These properties make them suitable for diverse applications, such as ratio metric fluorescence sensors for detecting Fe3+ ions within the 0–350 µM range, with high sensitivity (0.2 µM) and a low detection limit (4.93 μM). Additionally, they serve as material for white light-emitting diodes (W-LEDs), achieving CIE coordinates of (0.31, 0.30) and a rendering index of 94. The NCs also function as an optical thermometer with a sensitivity of 0.31 % K−1 at 320 K, making them ideal for temperature sensing applications. Moreover, their stability and dual-emissive nature make them highly effective in latent fingerprints (LFPs) detection, enabling high-resolution, level III fingerprint analysis. The dual emission properties of CDs and Cr3+ ions position these NCs as multifunctional materials, suitable for optical sensing, lighting, and security applications.

A Wearable Electrochemical Sensor Based on Single-Atom Pt Anchored on Activated NiCo-LDH/Ti3C2Tx for Real-Time Monitoring of Glucose.

Wearable, noninvasive sweat sensors enable real-time monitoring of metabolites in human health management. However, the commercial enzyme-based and currently nonenzymatic glucose sensor represents sluggish glucose oxidation kinetics and a narrow sensing range. Rational design of sensitive materials is significant yet faces a huge challenge. Herein, we construct a single-atom Pt supported on NiCo-LDH/Ti3C2Tx heterostructures (Pt1-NiCo-LDH/Ti3C2Tx) as the nonenzymatic electrochemical glucose sensor sensitive materials for selective detection of glucose level in human sweat. The obtained Pt1-NiCo-LDH/Ti3C2Tx with improved structural stability and enhanced charge transfer efficiency shows a low oxidation peak potential of 0.49 V, high sensitivity of 506.6 μA mM-1 cm-2, a low detection limit of 0.035 μM, and long-term stability toward the glucose detection. The wearable sensor, coupled with a wireless transmission module and a signal processing chip, is used for real-time perspiration glucose monitoring during outdoor exercise. The result is comparable to that of high-performance liquid chromatography (HPLC). This research provides a new paradigm for designing a wearable nonenzymatic electrochemical glucose sensor, enabling noninvasive real-time monitoring of glucose concentrations in human sweat.

Effect of Chloride Ions on the Electrochemical Performance of Magnesium Metal‐Organic‐Frameworks‐Based Semi‐Solid Electrolytes

AbstractThe majority of research on magnesium (Mg) electrolytes has focused on enhancing reversible Mg deposition, often employing chloride‐containing electrolytes. However, there is a notable gap in the literature regarding the influence of chloride ions in semi‐solid Mg electrolytes. In this study, we systematically explore the impact of chloride ions on Mg deposition/dissolution on a copper (Cu) anode using a semi‐solid electrolyte composed of Mg‐based mixed metal‐organic frameworks, MgCl2 and Mg[TFSI]2. We separate the Mg deposition/dissolution process from changes in the anode's surface morphology In this respect, the morphological and compositional transformations in the electrolyte and electrode following galvanostatic cycling are meticulously investigated. Initial potential cycling reveals the feasibility of Mg deposition/dissolution on Cu electrodes, albeit with reduced reversibility in subsequent cycles. Extending the upper potential limit to 4.0 V vs. Mg/Mg2+ enhances Mg dissolution, attributed to chloride ions facilitating Cu surface dissolution. Our findings provide insights into optimizing semi‐solid electrolytes for advanced Magnesium battery technologies.

Integrating All-rounder TiO2 Accelerated Electrochemiluminescence with Dual-Quenching PDA@COF Probes for Sensitive Quantification and Protein Profiling of Tumorous Exosomes.

Exosomes have been perceived as promising biomarkers for noninvasive cancer diagnosis and treatment monitoring. However, the sensitive and accurate quantification and phenotyping of exosomes remains challenging. Herein, a versatile electrochemiluminescence (ECL) aptasensor was proposed for the sensitive analysis of tumorous exosomes. Specifically, a ternary nanohybrid (Ru-HAuTiO2), by covalently linking ECL luminophore Ru(dcbpy)32+ with gold nanoparticles (AuNPs)-decorated hollow urchin-like TiO2 (HTiO2), was ingeniously designed as a highly luminescent and self-enhanced ECL nanoemitter. Notably, the porous HTiO2 played an "all-rounder" role, including the carrier for ECL luminophores and AuNPs, coreaction accelerator, and specific exosome capturing scaffold through Ti-phosphate coordination interaction. On the other hand, a polydopamine modified covalent organic framework (PDA@COF) was employed as a quencher to remarkably attenuate the ECL of Ru-HAuTiO2 through a dual-quenching mechanism, and further labeled with a specific aptamer (Apt) of exosomal surface protein. Based on forming a Ru-HAuTiO2/exosome/Apt-PDA@COF sandwich structure on the electrode, a "signal on-off" ECL platform for tumorous exosomes was constructed, realizing sensitive detection within the range of 3.1 × 103 particles/mL to 1 × 108 particles/mL and a low limit of detection of 1.41 × 103 particles/mL, achieving phenotypic profiling of surface proteins on different tumorous exosomes. This work provides a promising alternative method for the detection and analysis of exosomes.

Graphene quantum dots modified electrodes as electrochemical sensing tool towards the detection of codeine in biological fluids and soft drinks.

An electroanalytical method based on disposable screen-printed carbon electrodes modified with non-toxic carbonaceous nanodots is proposed as a reliable and effective device for codeine determination in biological fluids and soft drinks. Graphene quantum dots (GQDs), carbon quantum dots (CQDs) and carbon nanodots (CNDs) were evaluated as electrode modifiers for the determinationof the drug. The electroactive areas of the modified electrodes were assessed by cyclic voltammetry using potassium ferricyanide. Results demonstrated that GQDs provided the best analytical response for codeine, displaying an intense and well-defined anodic wave approximately 0.9V vs reference electrode. The method exhibits an acceptable linear dynamic range, low limits of detection and quantification (0.21 and 0.73µM, respectively), and satisfactory precision (below 3.9% expressed as relative standard deviation (RSD)) in saliva. Only the analysis of biofluids requires a simple extraction protocol. The feasibility and applicability of this novel approach were assessed by determining codeine in different matrices, with recoveries ranging from 69 to 112%. This cost-effective, simple, easily miniaturised and portable method was applied not only to biofluids but also for the direct detection of codeine in soft drinks combined with a codeine-enriched syrup, a medication that is being used to adulterate beverages, particularly at specific events (drinking and nightclub parties). There is no need forany sample treatment, demonstrating its versatility in analysing beverages for potential adulteration as well.