Search Results (248)

Acute Myocardial Infarction (AMI) is a critical cardiac condition that poses a substantial threat to myocardial function. Expedient diagnosis of AMI is paramount and relies on serological assays for rapid and accurate quantification of relevant biomarkers. Electrochemical sensors have emerged as promising candidates for this application, owing to their accessibility, operational simplicity, and high specificity. In this study, we developed a paper-based electrochemical immunosensor to detect cardiac troponin I in serum and saliva specimens. The electrode was fabricated using screen-printing technology with photographic paper as the substrate, employing graphite-based ink, nail polish, and acetone as the solvent. A quasi-reference electrode was constructed using silver powder-based ink, nail polish, and acetone. The immunosensor was prepared by modifying the working electrode with gold nanoparticles (AuNP) functionalized with cardiac troponin I antibodies (anti-cTnI) and bovine serum albumin (BSA). This modified electrode was subsequently used to detect the troponin I antigen. The analyses were performed in 0.1 mol L⁻¹ phosphate buffer medium, pH 7.00, in the presence of 5.0 mmol L⁻¹ of the potassium ferrocyanide probe. The immunosensor exhibited a sensitivity of 0.006 µA/fg mL⁻¹, a limit of detection of 9.83 fg mL⁻¹, and a limit of quantification of 32.79 fg mL⁻¹. Specificity studies conducted in the presence of other macromolecules demonstrated minimal interference, with relative standard deviations (RSD) below 5.00%, indicating a specific interaction with troponin I. Furthermore, the immunosensor demonstrated excellent reproducibility and stability. Upon application to serum and saliva samples, the immunosensor presented recoveries of approximately 99–105%, suggesting its potential applicability in clinical analyses. Full article

This work quantifies downtime caused by cyberattacks for eight critical urban services in Milan by coupling sectoral Continuous-Time Markov Chains (CTMCs) with an approximately equal-area H3 hexagonal grid of the city. The pipeline ingests OpenStreetMap infrastructure, simulates coupled failure/repair dynamics across sectors (power, telecom, hospitals, ambulance stations, banks, ATMs, surveillance, and government offices), and reports availability, outage burden (area under the infected/down curve, or AUC), and multi-sector distress probabilities. Cross-sector dependencies (e.g., power→telecom) are modeled via a joint CTMC on sector up/down states; uncertainty is quantified with nested bootstraps (inner bands for stochastic variability, and outer bands for parameter uncertainty). Economic impacts use sector-specific cost priors with sensitivity analysis (PRCC). Spatial drivers are probed via hotspot mapping (Getis–Ord $G_i^{*}$, local Moran’s I) and spatial regression on interpretable covariates. In a baseline short decaying attack, healthcare remains the most available tier, while power and banks bear a higher burden; coupling increases P(≥$k\mathrm{sectors}\mathrm{down})$ and per-sector AUC relative to an independent counterfactual, with paired-bootstrap significance at $\alpha =0.05$ for ATMs, banks, hospitals, and ambulance stations. Government offices are borderline, and telecom shows the same direction of effect but is not significant at $\alpha =0.05$. Under a persistent/adaptive attacker, citywide downtime and P(≥2) rise substantially. Costs are dominated by telecom/bank/power under literature-informed penalties, and uncertainty in those unit costs explains most of the variance in total loss. Spatial analysis reveals statistically significant hotspots where exposure and dependency pressure are high, while a diversified local service mix appears protective. All code and plots are fully reproducible with open data. Full article

Background/Objectives: The preoperative detection of sentinel lymph nodes (SLN) using technetium-99m (Tc-99m) is crucial for surgical staging in early-stage endometrial cancer (EC). The optimal imaging timing and modality remain debated. This study compares early planar scintigraphy (30 min), SPECT/CT (1 h), and 18-h planar scintigraphy after a single Tc-99m injection. Methods: A total of 125 patients with early-stage EC underwent SLN mapping with Tc-99m (120 MBq). Imaging included 30-min planar scintigraphy, SPECT/CT (1 h), and 18-h planar scintigraphy on the day of surgery. Detection sensitivity, the bilateral mapping rate, and image quality (signal-to-noise ratio (SNR), contrast factor (C-factor)) were evaluated, with intraoperative gamma probe detection and histopathology as references. Results: The 18-h planar scintigraphy achieved the highest SLN detection sensitivity (94.4%, 118/125), compared with SPECT/CT (87.2%, OR = 2.48, 95% CI: 0.98–6.27, p = 0.051) and 30-min scintigraphy (72.0%). Only the 18-h protocol underwent intraoperative and histopathological verification; results for 30-min planar and 1-h SPECT/CT were based on imaging alone, which limits direct comparability. Bilateral detection was higher at 18 h (80.80%) than SPECT/CT (73.60%). All SLNs detected at 18 h were confirmed intraoperatively and histologically, yielding 100% PPV (95% CI: 96.9–100.0%) and NPV (95% CI: 59.0–100.0%). The 18-h protocol showed superior imaging contrast (C-factor: 10.30 ± 1.22) despite lower residual activity. The method remained effective in patients with BMI ≥ 30 (94.00%). Only 1.60% of patients required hysterectomy before mapping due to background interference. Conclusions: The 18-h planar scintigraphy is a highly effective, low-cost, and accessible method for SLN detection in early-stage EC, potentially reducing the need for SPECT/CT, radiation exposure, and costs. Full article

pH is a critical parameter requiring precise monitoring across scientific, industrial, and biological domains. Fluorescent pH probes offer a powerful alternative to traditional methods (e.g., electrodes, indicators), overcoming limitations in miniaturization, long-term stability, and electromagnetic interference. By utilizing photophysical mechanisms—including intramolecular charge transfer (ICT), photoinduced electron transfer (PET), and fluorescence resonance energy transfer (FRET)—these probes enable high-sensitivity, reusable, and biocompatible sensing. This review systematically details recent advances, categorizing probes by operational pH range: strongly acidic (0–3), weakly acidic (3–7), strongly alkaline (>12), weakly alkaline (7–11), near-neutral (6–8), and wide-dynamic range. Innovations such as ratiometric detection, organelle-specific targeting (lysosomes, mitochondria), smartphone colorimetry, and dual-analyte response (e.g., pH + Al³⁺/CN⁻) are highlighted. Applications span real-time cellular imaging (HeLa cells, zebrafish, mice), food quality assessment, environmental monitoring, and industrial diagnostics (e.g., concrete pH). Persistent challenges include extreme-pH sensing (notably alkalinity), photobleaching, dye leakage, and environmental resilience. Future research should prioritize broadening functional pH ranges, enhancing probe stability, and developing wide-range sensing strategies to advance deployment in commercial and industrial online monitoring platforms. Full article

The tumor microenvironment plays an important role in tumor incidence, metastasis, and chemotherapy resistance. Novel therapeutic strategies targeting the tumor microenvironment have become a research focus in the field of biomedicine. In this study, we developed a smart small-molecule probe, TZ2, featuring pH/GSH dual-responsive characteristics. TZ2 exhibits a unique pH-dependent reaction mechanism: GSH is preferentially covalently modified with maleimide groups in acidic microenvironments (pH < 7), while specifically activating nucleophilic substitutions under alkaline conditions (pH > 7). It is worth noting that TZ2 effectively eliminates intracellular glutathione (GSH) in a time and concentration-dependent manner, demonstrating significant GSH depletion ability in various tumor cell lines. Pharmacodynamic studies have shown that TZ2 not only inhibits the cell cycle by regulating the expression of cell cycle-related proteins, but also effectively suppresses the cloning ability of cancer cells. Furthermore, TZ2 significantly increases the sensitivity of drug-resistant cancer cells to cisplatin. By integrating microenvironment modulation, real-time monitoring, and synergistic therapy, TZ2 provides a novel molecular tool and theoretical basis for tumor theranostics integration. Full article

Microfluidic modulation spectroscopy-infrared (MMS) offers a label-free, high-sensitivity approach for quantifying changes in protein secondary structures under native solution conditions. MMS subtracts the solvent backgrounds from sample signals by alternately flowing proteins and matched buffers through a microfluidic chamber, yielding clear amide I spectra from microliter volumes. In this study, we validated MMS on canonical globular proteins, bovine serum albumin, mCherry, and lysozyme, demonstrating accurate detection and resolution of α-helix, β-sheet, and mixed-fold structures. Applying MMS to the intrinsically disordered protein Tau, we detected environment-driven shifts in transient conformers: both the acidic (pH 2.5) and alkaline (pH 10) conditions increased the turn/unordered structures and decreased the α-helix content relative to the neutral pH, highlighting the charge-mediated destabilization of the labile motifs. Hyperphosphorylation of Tau yielded a modest decrease in the α-helical fraction and an increase in the turn/unordered structures. Comparison of monomeric and aggregated hyperphosphorylated Tau revealed a dramatic gain in β-sheet and a loss in turn/unordered structures upon amyloid fibril formation, confirming MMS’s ability to distinguish disordered monomers from amyloids. These findings establish MMS as a robust platform for detecting protein secondary structures and monitoring aggregation pathways in both folded and disordered systems. The sensitive detection of structural transitions offers opportunities for probing misfolding mechanisms and advancing our understanding of aggregation-related diseases. Full article

Background/Objectives: Microcrystalline cellulose (MCC) is a commonly used pharmaceutical excipient. At present, the catalytic potential of MCCs for the degradation of active pharmaceutical ingredients (APIs) has not been paid adequate attention. This study aims to investigate the representativeness of the pH value of an MCC determined in accordance with the pharmacopeia method to the acidity on its surface. Methods: We tested the differences between the catalytic activities of different MCCs and their supernatant prepared in accordance with the pharmacopeia method for the hydrolysis of ginsenoside Re, which is relatively stable in neutral or weak alkaline aqueous solutions but sensitive to acid. The sulfur content of the sulfuric acid-prepared MCC was measured using an ICP-OES. Results: All of the five tested commercially available and two self-prepared MCCs have been found to significantly promote the hydrolysis of ginsenoside Re. But their supernatants were neutral and chemically inert to Re. The sulfur content of the MCC prepared in this experiment using sulfuric acid hydrolysis was determined to be 109.60 µg/g, which is equivalent to 186 to 465 µM of sulfuric acid on the surface. Conclusions: The pH value of an MCC determined in accordance with the pharmacopeia method is not representative of the acidity on its surface. The primary reason should be that there is immobilized acid that is not so easily dissociated into the media. Ginsenoside Re is sensitive and applicable as a probe for the evaluation of the catalytic potential of pharmaceutically used MCCs. Full article

Gastroesophageal reflux disease (GERD) is a widespread condition that requires reliable and non-invasive diagnostic methods to minimize patient discomfort. This study presents a radiofrequency spectrophotometry sensor specifically designed to detect esophageal liquid flow and ionicity in real time without disrupting the patient’s daily life. The sensor operates by measuring dielectric properties and ionic conductivity through the thoracic plexus, eliminating the need for invasive probes or prolonged monitoring. A study conducted on 49 participants demonstrated the sensor’s ability to differentiate between various liquid media and identify beta dispersion relaxation as a biomarker for esophageal tissue damage, a key indicator of GERD progression. Additionally, alpha dispersion conductivity effectively distinguished reflux episodes, proving the sensor’s high sensitivity. Unlike traditional diagnostic techniques such as endoscopy or pH monitoring, this radiofrequency spectrophotometry sensor enables continuous, real-time reflux detection, allowing patients to maintain a normal lifestyle during assessment. The results validate its potential as an innovative alternative for GERD diagnosis and monitoring, with future research focused on clinical validation, optimization, and integration into long-term patient monitoring systems. Full article

Detecting heavy metal ions is essential for maintaining environmental safety, ensuring industrial quality control, and protecting public health. In this study, we have synthesized a novel Rhodamine B-based fluorescent probe, RhB-DCT, which is functionalized with 2,4-dichloro-1,3,5-triazine (DCT) to enhance selectivity and sensitivity for metal ions detection. The probe functions through a “turn-on” fluorescence mechanism activated by the opening of the spiro-lactam ring induced by Fe³⁺ ions, resulting in a distinct color change from colorless to deep pink. The RhB-DCT probe demonstrated a rapid and robust fluorescence response within seconds, exhibited a broad pH stability from 4 to 13, showed excellent reversibility, and possessed a low detection limit of 0.0521 μM, surpassing numerous existing fluorescent probes. The RhB-DCT probe exhibited significant selectivity for Fe³⁺ than other competing metal ions. The integration of high sensitivity, rapid response, and strong stability positions RhB-DCT as a viable option for real-time detection of Fe³⁺ ions in aqueous settings. This study demonstrates the efficacy of the RhB-DCT probe in environmental monitoring, water quality assessment, and analytical sensing platforms, serving as an effective and dependable tool for detecting heavy metal ions. Full article

In this research, an interdigitated gear-shaped working electrode is presented for cortisol sensing. Overall, the sensor was designed in a three-electrode system and was fabricated using direct laser scribing. A synthesized conductive ink based on graphene and polyaniline was further employed to enhance the electrochemical performance of the sensor. Scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy were employed for physicochemical characterization of the laser-induced graphene (LIG) sensor. Cortisol, a biomarker essential in detecting stress, was detected both in phosphate-buffered saline (PBS, pH = 7.4) and human serum within a linear range of 100 ng/mL to 100 µg/mL. Ferri/ferrocyanide was employed as the redox probe to detect cortisol in PBS. The electrochemical performance of the developed sensor was assessed via differential pulse voltammetry (DPV), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and chronoamperometry. The electrochemical performance demonstrates high sensitivity and selectivity alongside strong repeatability (relative standard deviation (RSD) = 3.8%, n = 4) and reproducibility (RSD = 5.85%, n = 5). Overall, these results highlight the sensor’s reliability, high sensitivity, and repeatability and reproducibility in the detection of cortisol. The sensor successfully detected cortisol in the complex medium of human serum and effectively distinguished it in a ternary mixture containing cortisol and dopamine. Also, the use of direct laser writing on Kapton film makes the approach cost-effective and thus disposable, making it suitable for chronic stress diagnostics and neurological research applications. Full article

Fluorescent proteins (FPs) are widely used as optical probes in molecular and cell biology. tKeima is a tetrameric, large Stokes shift red fluorescent protein and the ancestral protein of mt-Keima, which is widely applied as a pH-sensitive fluorescent probe. While the pH sensitivity of mt-Keima is well characterized, the pH-dependent properties of the ancestral tKeima have not been comprehensively elucidated. To obtain a better understanding of the effects of pH on tKeima, its fluorescent emission intensity at various pH levels was measured, and its crystal structure at pH 4.0 was determined at a resolution of 2.2 Å. The fluorescence emission intensity of tKeima at pH 4.0 decreased by approximately 65% compared with its peak emission at pH 10.0. The crystal structure of tKeima at pH 4.0 revealed both cis and trans conformations of the chromophore, in contrast to previously determined structures at pH 8.0, which showed only the cis conformation. This indicates that pH induces a conformational change of the chromophore in tKeima. Both the cis and trans conformations in tKeima were stabilized by hydrogen bonds with neighboring residues. A comparison of tKeima at pH 4.0 with tKeima at basic pH, as well as with mKeima, highlights its unique structural properties. These results provide a deeper understanding of the structural basis for the pH-induced fluorescence emission changes in the Keima family. Full article

Hydrogen sulfide (H₂S) is an important signaling molecule involved in various physiological and pathological processes, making its accurate detection in biological systems highly desirable. In this study, two fluorescent probes (M1 and M2) based on 1,8-naphthalimide were developed for H₂S detection via a nucleophilic aromatic substitution. M1 demonstrated high sensitivity and selectivity for H₂S in aqueous media, with a detection limit of 0.64 µM and a strong linear fluorescence response in the range of 0–22 µM of NaHS. The reaction kinetics revealed a rapid response, with a reaction rate constant of 7.56 × 10² M⁻¹ s⁻¹, and M1 was most effective in the pH range of 6–10. Mechanism studies using ¹H NMR titration confirmed the formation of 4-hydroxyphenyl-1,8-naphthalimide as the product of H₂S-triggered nucleophilic substitution. M1 was applied in MDA-MB-231 cells for cell imaging, in which M1 provided significant fluorescence enhancement upon NaHS treatment, confirming its applicability for detecting H₂S in biological environments. In comparison, M2, designed with extended conjugation for red-shifted emission, exhibited weaker sensitivity due to the reduced stability of its naphtholate product and lower solubility. These results demonstrate that M1 is a highly effective and selective fluorescent probe for detecting H₂S, providing a valuable resource for investigating the biological roles of H₂S in health and disease. Full article

The extraction of the Generalized Parton Distributions of the nucleons from phenomenological analyses of experimental data presents a challenging problem which is being actively studied in the literature. Due to theoretical limitations of some of the well-known channels, currently many new processes are being analyzed in the literature as potential novel probes. In this proceeding we propose to use the exclusive photoproduction of ${\eta }_c\gamma$ pairs as a new channel for study of the GPDs. Our analysis shows that this process is primarily sensitive to the unpolarized gluon GPDs $H_g$ in the Efremov-Radyushkin-Brodsky-Lepage (ERBL) kinematics. The numerical estimates of the cross-section and the expected counting rates for middle-energy photoproduction experiments show that expected counting rates are sufficiently large for a dedicated experimental study at the future Electron-Ion Collider (EIC) or in ultraperipheral collisions at the LHC. The total (integrated) photoproduction cross-section ${\sigma }_{\mathrm{tot}}^{\gamma p\to \gamma {\eta }_{c}p}$ in this kinematics scales with energy W as ${\sigma }_{\mathrm{tot}}^{\gamma p\to \gamma {\eta }_{c}p}\left(W,M_{\gamma {\eta }_c}\ge 3.5\mathrm{GeV}\right)\approx 0.48\mathrm{pb}{\left({\displaystyle \frac{W}{100\mathrm{GeV}}}\right)}^{0.75},$ and yields a few thousands of events per $100{\mathrm{fb}}^{-1}$ of the integrated luminosity. Full article

Ciprofloxacin is metabolized from enrofloxacin for use in poultry to manage respiratory and gastrointestinal diseases, raising concerns due to its widespread tissue distribution and prolonged systemic persistence. This lateral flow immunoassay was designed to detect ciprofloxacin using an alternative IgY antibody binded with gold nanoparticles to detect ciprofloxacin residue in raw pork meat samples. The developed strip test achieved adequate sensitivity and specificity under the optimized conditions for pH, which is 7.8, and 20% of MeOH in 0.01 M phosphate buffer containing 1% Tween-20 was used for the buffer composition. An antibody concentration of 1.25 µg/mL was used to bind with gold nanoparticles as a probe for detection. The concentration of the test line (coating antigen) and control line (anti-IgY secondary antibody) was 0.5 mg/mL and 0.2 mg/mL, respectively. The efficiency of the developed strip test showed sensitivity with a 50% inhibitory concentration (IC₅₀) of ciprofloxacin at 7.36 µg/mL, and the limit of detection was 0.2 µg/mL. The proposed strategy exhibited potential for monitoring ciprofloxacin in raw pork samples. Full article

Carbon dots (CDs) are efficient fluorescent probes for metal ion detection due to their high sensitivity, nontoxicity and stability, but their rich functional groups lead to simultaneous responses to multiple ions. So, how to realize highly selective detection for specific ions is still a challenging task. In this work, “bare CDs” were synthesized using the electrochemical stripping method, followed by grafting with hydroxyl and carboxyl groups following the hydrothermal method with boric acid. Transmission electron microscopy, an X-ray diffractometer, Fourier transform infrared spectroscopy, UV–visible spectrophotometers and a fluorescence spectrometer were used to characterize their morphology, surface functional groups and optical properties, respectively. The modified CDs exhibit a high sensitivity of 65% and selectivity towards Cu²⁺. Meanwhile, they also exhibited a short response time of less than 1 min and a good stability in terms of pH and ionic strength. Full article