Search Results (6,829)

Two novel, simple, and sensitive methods for the assay of Gliquidone (GLI) were developed and validated in various matrices, including raw material, Glurenor^®® tablets, and spiked human plasma (spectrofluorometric approach only). The first method employs spectrofluorimetry to measure GLI fluorescence emission at 404 nm upon excitation at 311 nm, using a solvent mixture of phosphate buffer (pH 4), β-cyclodextrin, and methanol. The second one was colorimetric, based on GLI’s reaction with 7,7,8,8-tetracyanoquinodimethane (TCNQ) in acetone, forming a stable colored product whose absorbance was quantitatively measured at 745.5 nm. The spectrofluorometric approach showed a linear range of 0.05–0.45 µg·mL⁻¹ with a mean recovery of 100.43 ± 0.88%, while the colorimetric method demonstrated a broader linear range (20–200 µg·mL⁻¹) and mean recovery of 101.10 ± 1.27%. GLI and TCNQ react in a 1:1 ratio at 1.7 × 10⁻² M concentrations. Both methods were successfully applied without excipient interference. Sustainability, practicality, and performance (validation) assessments (AGREE, BAGI, and RAPI) favored the spectrofluorometric method due to higher sensitivity, a broader working range, lower detection limits, and better overall practical and environmental performance. In conclusion, the spectrofluorometric approach offers high sensitivity and precision, while the colorimetric one provides a wider linear range and greater complex stability. Full article

Within the current administrative boundaries of the city of Lublin, fragments of roadside tree avenues of various historical origins and periods of establishment have been preserved, including former tree-lined roads leading to rural and suburban residences from the 18th and 19th centuries. This avenue once led to the manor in Konstantynów and now serves as the main road through the campus of the John Paul II Catholic University of Lublin (Katolicki Uniwersytet Lubelski—KUL). As one of the last surviving elements of the former rural landscape, the Konstantynów avenue represents a symbolic link between past and future. The research combines acoustic tomography and chlorophyll fluorescence analysis, providing a precise and non-invasive evaluation of the internal structure and physiological performance of 34 small-leaved linden trees (Tilia cordata Mill.). This methodological approach allows for early detection of stress symptoms and structural degradation, offering a significant advancement over traditional visual assessments. The study area is an intensively used urban campus, where extensive surface sealing beneath tree canopies restricts rooting space. The degree of surface sealing (paving) directly beneath the tree canopies was also measured. Based on the statistical analysis, a weak a non-significant weak negative correlation (r = −0.117) was found between the proportion of sealed surfaces within the Tree Protection Zone (TPZ) and the Fv/Fm vitality index, indicating that higher levels of surface sealing may reduce tree vitality; however, this relationship was not statistically significant (p = 0.518). The study provides an evidence-based framework for conserving historic trees by integrating advanced diagnostic tools and quantifying environmental stress factors. It emphasizes the importance of improving rooting conditions, integrating heritage trees into urban planning strategies, and developing adaptive management practices to increase their resilience. The findings offer a model for developing innovative conservation strategies, applicable to historic green infrastructure across Europe and beyond. Full article

Precise regulation of micropipette outlet flow is critical for fluorescence imaging in vivo micromanipulations. In such procedures, a micropipette with a micro-sized opening is driven by gas pressure to deliver internal solution into the in vivo environment. The outlet flow rate needs to be precisely regulated to ensure a uniform and stable fluorescence distribution. However, conventional manual pressure injection methods face inherent limitations, including insufficient precision and poor reproducibility. Existing commercial microinjection systems lack a quantitative relationship between pressure and flow rate. And existing calibration methods in the field of microfluidics suffer from a limited flow-rate measurement resolution, constraining the establishment of a precise pressure–flow quantitative relationship. To address these challenges, we developed a closed-loop pressure regulation system with 1 Pa-level control resolution and established a quantitative calibration of the pressure–flow relationship using a droplet-based method. The calibration revealed a linear relationship with a mean pressure–flow gain of 4.846 $\times {10}^{-17}{\mathrm{m}}^3·{\mathrm{s}}^{-1}·{\mathrm{P}\mathrm{a}}^{-1}$ (R² > 0.99). Validation results demonstrated that the system achieved the target outlet flow rate with a flow control error less than 10 fL/s. Finally, the application results in brain-slice environment confirmed its capability to maintain stable fluorescence imaging, with fluorescence intensity fluctuations around 1.3%. These results demonstrated that the proposed approach provides stable, precise, and reproducible flow regulation under physiologically relevant conditions, thereby offering a valuable tool for in vivo micromanipulation and detection. Full article

Probiotic enumeration in foods and beverages remains anchored in culture dependent colony-forming unit (CFU) counts, the regulatory gold standard for label compliance. However, culturability does not fully equate to viability as environmental stresses can convert probiotic cells into a viable but non-culturable (VBNC) state, where they remain metabolically active but undetectable by CFU counts. Microencapsulation can provide a degree of protection to probiotics against stress; nevertheless, this blind spot in quantification forces manufacturers to overdose formulations or risk non-compliance with health benefits claims. Thus, the efficacy of probiotics may be underestimated when evaluation relies solely on CFU, creating a false dichotomy between VBNC and non-viable cells. Culture-independent methods, including flow cytometry quantification of active fluorescent units (AFUs), viability PCR/dPCR, and rRNA-targeted Flow-FISH, can aid closing this gap by detecting metabolically active cells non-detectable by culturing, providing complementary quantification data to CFU counts alone. Understanding the relationship between quantification by culture and culture-independent methods provides a more accurate measure of probiotic dose delivery in functional foods and beverages. This review covers the current understanding of VBNC state, including induction, detection, and resuscitation in probiotics, with emphasis on experimental controls that differentiate true VBNC resuscitation from population growth. Case studies in Lactobacillus and Bifidobacterium illustrate triggers, molecular mechanisms, and methodological advances. Finally, guidance is provided for the development of an integrated quantification approach that reconciles culture-dependent and culture-independent data, ultimately aiming to improve CFU count accuracy through the controlled resuscitation of VBNC cells. Full article

Gynaephora qinghaiensis is a major grassland pest common in the alpine meadows of the western plateau of China, and its biological behavior is affected by the synergy of a variety of chemicals in the environment. OBPs can dissolve and transport odor molecules such as volatile plant compounds through lymphatic fluid, which plays an important olfactory-to-olfactory role. However, the specific function of OBPs in the interaction mechanism between moths and volatile plant compounds is still unknown. The purpose of this study was to analyze the binding characteristics of GqinOBP10 and its volatile plant compounds in moths and to explore its role in the olfactory perception mechanism of moths so as to study the corresponding target ligands and achieve green control. The purified GqinOBP10 was subjected to fluorescence competitive binding to eight ligands. The 3D modeling of GqinOBP10 was carried out by the SWISS-MODEL website, and the molecular docking was carried out by Autodock 4.2.6 software, and the binding of GqinOBP10 to eight ligands was simulated and verified. The results showed that the cloned strain with the full length of GqinOBP10 was cloned. The fluorescence competition binding results showed that GqinOBP10 had strong binding ability to eight volatile plant compounds, among which the binding ability to 2-Amino-1-phenylethanol and 2-Oleoylglycerol was the strongest, and had high binding ability with the other six ligands. The molecular docking results showed that the binding energy of GqinOBP10 and eight odorant molecules was negative, and all of them could form 1~4 hydrogen bond for binding, among which the binding performance with 2-Oleoylglycerol was the best. The findings suggest that dsOBP10 injection leads to a notable decrease in both the expression levels of GqinOBP10 and the antennal potential response in male and female tissues. This indicates that GqinOBP10 is likely crucial for the localization and recognition of host plants in G. qinghaiensis. By silencing GqinOBP10, the olfactory perception of host volatiles is significantly impaired, highlighting the protein’s importance in the caterpillars’ ability to detect and respond to their environment. These insights provide a valuable basis for developing targeted attractants, potentially enhancing pest management strategies by manipulating olfactory cues in these caterpillars. Further research could explore the specific mechanisms by which GqinOBP10 influences olfactory perception and host plant selection. Full article

This study establishes a detection method based on image recognition to interpret and quantitatively analyze fluorescent rapid test kits for influenza. The method operates in a dark chamber equipped with a UV-LED, where the fluorescence of the test kit is excited by the UV-LED and subsequently captured using a camera module. The captured images are processed by segmenting the regions of interest (ROI), converting them to grayscale images, and analyzing the grayscale value distributions to identify the control (C) and test (T) line regions. By comparing the values of the C and T lines, the concentration is determined to achieve quantitative analysis. In the linearity validation experiments, the concentrations of influenza A (H1N1) specimens are 2, 4, 6, 8, and 10 ng/mL, achieving a coefficient of determination (R²) of 0.9923. For influenza B (Yamagata) specimens, concentrations of 6, 8, 10, 12.5, and 25 ng/mL resulted in an R² of 0.9878. The established method enables the detection of both influenza A (H1N1) and influenza B (Yamagata), replacing visual qualitative interpretation with quantitative analysis. Currently, the detection method developed in this paper is designed for use exclusively in a dark chamber and is specifically applied to fluorescent rapid tests. It cannot be directly used with conventional colloidal gold-based rapid test reagents. In the future, the proposed detection approach could be integrated with neural networks to enable its application to non-fluorescent rapid test interpretation and to operate beyond the dark chamber environment, for example by utilizing smartphone imaging for result interpretation under normal lighting conditions. Full article

Rosa rugosa (R. rugosa) is a commercially important ornamental species within the genus Rosa, highly valued in the horticultural market. With the increasing availability and improved annotation of Rosa genomes, establishing an efficient genetic transformation system has become essential for validating candidate gene functions. As a common intermediate tissue in plant regeneration, callus has been successfully used to establish genetic transformation systems in numerous species. In this study, we characterized the morphological and physiological differences between embryogenic and non-embryogenic calli in R. rugosa. The embryogenic callus exhibited significantly higher catalase (CAT) activity and proline (PRO) content than the non-embryogenic callus. However, its growth rate was markedly slower. Antibiotic sensitivity assays identified the optimal selection concentrations for non-embryogenic callus as 35 mg/L for kanamycin and 13 mg/L for hygromycin. We subsequently introduced the phytoene synthase (RrPSY1) gene into non-embryogenic callus, with positive transformants identified using GFP fluorescence detection and PCR analysis. The overexpression of RrPSY1 significantly increased the yellow pigment substances in the callus, confirming the establishment of an effective genetic transformation system for non-embryogenic calli in R. rugosa. This system provides a useful technical platform for the manipulation of metabolic products and the verification of related gene functions in rose. Full article

Gliomas, the most common primary brain tumors, present significant diagnostic and treatment challenges due to their infiltrative nature and heterogeneity. Our previous research revealed that glioma tumors in both animals and humans accumulate beta-amyloid protein (Aβ), detectable through immunohistochemical methods or staining with amyloid-specific dyes. We hypothesize that beta-amyloid-specific dyes could serve as glioma markers, potentially enabling the delineation of glioma tumors or targeted therapeutics delivery. In this study, the specificity and blood-brain barrier permeability of two fluorescent beta-amyloid-specific dyes, Brilliant Blue G (BBG) and BODIPY-based Amyloid Probe-1 (BAP-1), were evaluated in C57Bl/6 mouse glioma implantation models using GL261 and KR158 glioma cells. The findings demonstrate that both BBG and BAP-1 selectively stain gliomas, providing a clear contrast from normal brain tissue. The study results open avenues for further development of glioma visualization methods and targeted therapeutic delivery strategies for clinical applications. Full article

This review summarizes the application of spectroscopic techniques in pesticide residue analysis, with a focus on the principles, advancements, and challenges of surface-enhanced Raman spectroscopy (SERS), infrared spectroscopy, fluorescence spectroscopy, ultraviolet-visible (UV-Vis) spectroscopy, and hyperspectral imaging (HSI). Nanomaterials, serving as key enhancing substrates, significantly improve the sensitivity and selectivity of these detection methods. This article critically evaluates the strengths and limitations of each technique in practical applications—such as the exceptional sensitivity of SERS versus its dependence on substrate reproducibility, and the non-destructive nature of hyperspectral imaging against the complexity of data processing. Future research directions should emphasize the development of intelligent nanosubstrates, the construction of cross-modal spectral databases, and the miniaturization of integrated spectroscopic-mass spectrometric instruments. These advancements are essential for enhancing the efficiency and reliability of agricultural and food safety monitoring. Full article

This study assessed the concentrations and spatial patterns of heavy metals in fine particulate matter with aerodynamic diameter below 2.5 $\mu$m and coarse particulate matter with aerodynamic diameter below 10 $\mu$m in Santo Domingo, Dominican Republic, during 2022. Thirty 24 h samples were collected using portable low-volume samplers across representative urban environments. Elemental concentrations of arsenic, cadmium, chromium, copper, iron, manganese, nickel, lead, vanadium, and zinc were quantified by energy-dispersive X-ray fluorescence. To address data below detection limits, regression on order statistics was applied. Copper and zinc exhibited the highest mean concentrations, pointing to strong anthropogenic inputs, while vanadium and iron showed pronounced spatial variability. Principal component analysis identified traffic and industrial activities as dominant sources. These findings provide baseline evidence for heavy metal pollution in Caribbean urban air and emphasize the need for continuous monitoring and effective regulatory strategies to mitigate potential health risks. Full article

Lung cancer remains one of the deadliest cancers worldwide, which highlights the urgent need for new diagnostic tools to detect reliable biomarkers. To enable scalable and cost-effective production, we developed reusable PDMS stamps patterned with electrodes to print flexible electrodes on PET substrates using a microcontact printing (µCP) approach. PET was chosen not only for its flexibility but also as a more sustainable alternative to conventional rigid materials. On these electrodes, three sensing platforms were tested for neuron-specific enolase (NSE) detection: APTES-based monolayers, electrospun PVA/alginate nanofibers, and electropolymerized polypyrrole (PPy) films. Voltammetric and fluorescence/AFM analyses confirmed that all three platforms could recognize the target analyte, with the PPy-CdTe configuration showing the strongest signal variation. Impedance spectroscopy further supported this finding, revealing a clear linear correlation between charge transfer resistance (RCT) and NSE concentration. The PPy-CdTe sensor demonstrated high sensitivity and consistent performance for NSE detection, achieving a detection limit (LOD) of 8.05 pg·µL⁻¹ and a quantification limit (LOQ) of 26.84 pg·µL⁻¹. Full article

ZnO nanostructures have attracted attention as transducer materials in optical biosensing platforms due to their wide bandgap, defect-mediated photoluminescence, high surface-to-volume ratio, and tunable morphology. This review examines how the dimensionality of ZnO nanostructures affects biosensor performance, particularly in terms of charge transport, signal transduction, and biomolecule immobilization. The synthesis approaches are discussed, highlighting how they influence crystallinity, defect density, and surface functionalization potential. The impact of immobilization strategies on sensor stability and sensitivity is also assessed. The role of ZnO in various optical detection schemes, including photoluminescence, surface plasmon resonance (SPR), localized (LSPR), fluorescence, and surface-enhanced Raman scattering (SERS), is reviewed, with emphasis on label-free and real-time detection. Representative case studies demonstrate the detection of clinically and environmentally relevant targets, such as glucose, dopamine, cancer biomarkers, and SARS-CoV-2 antigens, with limits of detection in the pico- to femtomolar range. Recent developments in ZnO-based hybrid systems and their integration into fiber-optic and microfluidic platforms are explored as scalable solutions for portable, multiplexed diagnostics. The review concludes by outlining current challenges related to reproducibility, long-term operational stability, and surface modification standardization. This work provides a framework for understanding structure–function relationships in ZnO-based biosensors and highlights future directions for their development in biomedical and environmental monitoring applications. Full article

Background/Objectives: The multi-attribute method (MAM) has found diverse use in the analytical characterization of therapeutic protein products during their development and production. As the MAM matures it has the potential to enter quality control (QC) laboratories, consolidating and replacing many less informative chromatographic techniques; however, this requires an appropriate risk assessment and understanding of method capability. Methods: A validated MAM approach was used to quantify product quality attributes (PQAs) using three different mass spectrometers across two laboratories; the results were compared to conventional hydrophilic interaction chromatography–fluorescence detection (HILIC-FLD) and cation exchange chromatography–ultraviolet (CEX-UV) techniques. Results: Stressed, long-term, and accelerated stability studies were performed, and their effects on glycosylation, deamidation, oxidation and N- and C-termini were quantified. Conclusions: Overall, the inter-instrument inter-laboratory data provided here showed important considerations for transferring methods between laboratories and establishing the correlation between the MAM and conventional data, elements which are necessary to transition the MAM to the QC environment and ultimately achieving the goal of replacing orthogonal QC methods. Full article

Multiple-mode immunoassays have the advantages of self-correction, self-validation, and high accuracy and reliability. In this work, we developed a strategy for the design of triple-mode immunoassays with the self-assemblies of three-in-one small molecules as signal reporters. Pyrroloquinoline quinone (PQQ), with a well-defined redox peak and excellent spectroscopic and fluorescent signals, was chosen as the signaling molecule. PQQ was coordinated with Cu²⁺ to form metal–organic nanoparticle as the signal label. Hexahistidine (His₆)-tagged recognition element (recombinant streptavidin) was attached to the Cu-PQQ surface through metal coordination interaction between the His₆ tag and the unsaturated metal site. The captured Cu-PQQ nanoparticle released a large number of PQQ molecules under an acidic condition, which could be simultaneously monitoring by electrochemical, UV-vis, and fluorescent techniques, thereby allowing for the development of triple-model immunoassays. The three methods were used to determine the concentration of carcinoembryonic antigen (CEA) with the detection limits of 0.01, 0.1, and 0.1 ng/mL, respectively. This strategy opens up a universal route for the preparation of multiple-model signal labels and the oriented immobilization of bioreceptors for molecular recognition. Full article

Tuberculosis remains a serious global public health challenge and requires the development of rapid, sensitive, and specific diagnostic tools for effective treatment and disease control. Bioimaging reporters are promising diagnostic tools that exploit the unique biochemical properties of Mycobacterium tuberculosis for real-time detection of viable cells from clinical samples. Moreover, these methods offer significant advantages over the conventional methods currently used in practice, including reduced assay time, increased specificity, and the ability to discriminate viable cells from dead cells. In this review, we highlight reporters of a different nature that the enable direct detection of Mycobacterium tuberculosis, eliminating complex sample preparation. Such reporters could serve as powerful tools in fluorescence microscopy, provide alternative strategies for automated culture-based diagnostic systems, and offer new approaches for developing point-of-care methods and diagnostic devices suitable for clinical practice. Full article