Glycosylation, as one of the most prevalent forms of post-translational modification, plays a pivotal role in tumor progression through structural alterations of serum N-glycans in hepatocellular carcinoma (HCC). In this study, we systematically investigated these N-glycan profiles as potential prognostic biomarkers for predicting patient survival outcomes. This study enrolled a cohort of 150 hepatitis B virus (HBV)-related HCC patients (BCLC stages A-D) who received treatment and follow-up monitoring at Southwest Medical University Hospital from 2022 to 2023. Additionally, 105 chronic hepatitis B (CHB) patients, 50 healthy individuals matched for age and gender were recruited as controls. Serum N-glycan profiles were characterized using capillary gel electrophoresis laser-induced fluorescence detection (CGE-LIF). The relative intensities (RIs) of Peak 9 (NA3Fb) was specifically elevated in HBV-related HCC patients. This peak emerged as an independent predictor of survival (p = 0.004), strongly correlated with advanced tumor stage (p < 0.01), and it was associated with HBsAg loss following anti-PD-1 therapy. MGAT4A, the gene implicated in regulating Peak 9, is likely significantly involved in critical pathways driving HCC progression. Serum N-glycan profiling represents a promising noninvasive tool for monitoring prognosis and outcomes in HCC patients. Peak 9 (NA3Fb) was identified as a prognostic biomarker significantly associated with clinical outcomes in HBV-related HCC.

The microRNA let-7a plays a pivotal role in tumor suppression by regulating RAS and other oncogenes. However, due to its extremely low abundance in individual cells, quantitative analysis of let-7a at the single-cell level remains challenging. In this study, we developed an electrophoresis-assisted intracellular catalytic hairpin assembly branched hybridization chain reaction-MNAzyme tandem signal amplification strategy. By integrating multimodal cascade signal amplification with microchip electrophoresis separation and laser-induced fluorescence detection, we achieved a detection limit of 8 × 10-16 M, which is sufficient for single-cell quantification of let-7a. The levels of let-7a in cell lysates and in 20 individual cells from three cell lines were quantitatively analyzed with this method on a microfluidic chip electrophoresis platform. The results revealed marked differences in let-7a expression not only among distinct cell types but also between individual cells of the same type. The average copy numbers of let-7a per cell were determined to be 3258 in HL-7702 cells, and 1408 and 200 in MCF-7 and A549 cancer cells, respectively, underscoring the characteristic low expression of let-7a in various tumor cells, likely associated with its tumor-suppressive function. This method provides a powerful tool for single-cell biological studies of let-7a.

The sensitivity of laser-induced fluorescence (LIF) to slight biochemical changes has made it an effective tool for non-invasive biomedical diagnostics. Since milk is a biological fluid that is both optically and biochemically complex, we employed it as a model sample to evaluate how effectively LIF senses thermally induced molecular changes. Full-fat and skimmed milk samples were systematically examined under 405 nm excitation both before and after controlled heating. The collected fluorescence spectra were then subjected to chemometric analysis using Principal Component Analysis (PCA) for unsupervised classification and Partial Least Squares Regression (PLSR), Support Vector Classifier (SVC), and Random Forest (RF) for predictive modeling. The statistical significance of the observed spectral changes was validated using paired t-tests. Following thermal processing, the emission band at around 533 nm, which corresponds to riboflavin, was significantly reduced, based on fluorescence spectra. The statistical significance of this decrease was validated by paired t-tests (p <0.0001). The discriminative power of LIF was further confirmed by chemometric evaluation: PCA successfully classified samples based on both fat content and thermal treatment, with the first two principal components predicting almost 85% of the total variance. The robustness of the approach was verified by the high calibration and cross-validated prediction accuracy (R2 >0.95) achieved by PLSR. Excellent classification performance was achieved by the SVM classifier with RBF kernels, correctly classifying 100% of data sets. Good model generalization without overfitting is indicated by the close agreement between the test set and cross-validation accuracies. Furthermore, the robustness and generalizability of the model were confirmed by the low out-of-bag error rate in RF implementations. These results show the potential of LIF as a sensitive, non-destructive method for assessing thermal and metabolic changes in biomedical contexts and validate milk as a practical surrogate system for comparing fluorescence-based methods.

Proton Exchange Membrane Fuel Cells (PEMFCs) is one of the best promising clean technologies in future. Numerous research activities are going on regarding to stability and thermal management of PEMFC. This reserch aim to study the scattering dynamic inside PEMFC in self-generated heat, laser field and scattering particles. To fulfil this objective first, authors developed theoretical model and then verified some parameters of theoretical model with experimental methods. For theoretical model authors formulated transition matrix using thermal Volkov wave function and thermal potential of hydrogen to study scattering dynamic. For experimental method, authors developed a PEMFC prototypes and applied diffident condition (heat and laser) to observed the data for verification of theoretical model. The developed differential cross section (DCS) model shows that with increasing temperature DCS increase theoretically and experimentally found that increasing in temperature decreasing in voltage. So, the DCS increasing with decreasing in voltage which is verified both theoretically and experimentally. In addition, we also observed that DCS effect by different parameters of PEMFC like charge transfer, charge density, efficiency, voltage, activation potential etc. and scattering parameters like momentum, scattering angle, incidence energy, distance separation etc. This finding help both academic field and non-academic field like scanning tunneling microscopy, laser-induced fluorescence, quantum computing and nanophotonic sensors perform. The finding finds that the supply temperature negatively influences PEMFC performance, which is attributed to higher particles’ resistance and entropy, hence indicating how stringent is the requirement for an accurate thermal management for enhancing fuel cell efficiency.

Simultaneous planar laser-induced fluorescence and optical emission spectroscopy system with spatiotemporal resolution for arc jet flow diagnostic

Photodynamic therapy is a cancer treatment that relies on a photosensitizer (PS) to generate reactive oxygen species upon light activation, thereby destroying cancer cells. The photophysical properties of porphyrins make them effective PSs, while nanoparticles (NPs) enhance their delivery and stability. The bioavailability and targeting efficiency of NPs-PS complexes may be improved through transport via human serum albumin (HSA). This study investigates the HSA binding affinity with 5,10,15,20-(Tetra-4-carboxyphenyl)porphyrin (TCPP) and with TiO2-TCPP complexes. The interactions were analyzed using UV-Vis absorption, laser-induced fluorescence (LIF), and FTIR spectroscopy. Molecular docking was performed and provided consistent binding constant values for the TCPP–HSA complex with UV-Vis absorption measurements. LIF data revealed a slightly lower affinity when compare free porphyrin with TiO2-TCPP, possibly due to competitive binding between TiO2 and HSA. Docking simulations indicated that TCPP favorably interacts with amino acid residues located in subdomains IB and IIIA of HSA, supporting a preferential binding near Sudlow site I. FTIR measurements revealed conformational changes in HSA for both its interactions with TCPP and TiO2-TCPP, including alterations in α-helical content and reorganization of the hydrogen bonding network within the polypeptide backbone.

Detection of residual microbial biomarkers in bacterial cellulose using laser-induced fluorescence spectroscopy.

Capillary electrophoresis with laser induced fluorescence for the analysis of biological thiols in exhaled breath condensate after preconcentration using gold and gold-grafted magnetic nanoparticles.

Proton Exchange Membrane Fuel Cells (PEMFCs) is one of the best promising clean technologies in future. Numerous research activities are going on regarding to stability and thermal management of PEMFC. This reserch aim to study the scattering dynamic inside PEMFC in self-generated heat, laser field and scattering particles. To fulfil this objective first, authors developed theoretical model and then verified some parameters of theoretical model with experimental methods. For theoretical model authors formulated transition matrix using thermal Volkov wave function and thermal potential of hydrogen to study scattering dynamic. For experimental method, authors developed a PEMFC prototypes and applied diffident condition (heat and laser) to observed the data for verification of theoretical model. The developed differential cross section (DCS) model shows that with increasing temperature DCS increase theoretically and experimentally found that increasing in temperature decreasing in voltage. So, the DCS increasing with decreasing in voltage which is verified both theoretically and experimentally. In addition, we also observed that DCS effect by different parameters of PEMFC like charge transfer, charge density, efficiency, voltage, activation potential etc. and scattering parameters like momentum, scattering angle, incidence energy, distance separation etc. This finding help both academic field and non-academic field like scanning tunneling microscopy, laser-induced fluorescence, quantum computing and nanophotonic sensors perform. The finding finds that the supply temperature negatively influences PEMFC performance, which is attributed to higher particles' resistance and entropy, hence indicating how stringent is the requirement for an accurate thermal management for enhancing fuel cell efficiency.

Toward rapid testing for molecular authentication: Novel method for multianalyte identification of olive, sunflower, soy, sesame and corn DNA by visual biosensing.

Planar laser-induced fluorescence visualization of microporous-wall seeping gas films in supersonic boundary layers

Three-dimensional reconstruction of low-pressure supersonic flows via physics-informed neural network enhanced laser-induced fluorescence imaging

An experimental study of the active control of wake flow in a narrow gap using a sweeping jet generated by a fluidic oscillator was conducted using planar laser-induced fluorescence and time-resolved particle image velocimetry. Spectral proper orthogonal decomposition of the velocity fields shows that the flow dynamics in the narrow gap, controlled by the sweeping jet, depends on the ratio of the jet oscillation frequency to the natural frequency of the Karman vortex street in the narrow gap. An increase in the jet oscillation frequency above the natural frequency causes the flow to reorganize into bimodal shedding of vortex structures—two Karman vortex streets with distinct wavelengths—within the narrow gap, which transition downstream to a unimodal flow regime at frequencies near the natural one. This extends the range of controllable spatiotemporal scales and enhances mixing efficiency. The results of this work are significant for the development of methods for detecting flow blockages in high-power equipment of nuclear power plants.

Chemical oxygen demand (COD) serves as a critical indicator for assessing the extent of water pollution caused by organic matter. This study proposes an integrated COD detection methodology that combines laser absorption spectroscopy with laser-induced fluorescence spectroscopy, enabling accurate measurement of COD parameters across a wide concentration range. For high-concentration COD, conventional ultraviolet absorption spectrophotometry based on the Lambert–Beer law is employed. However, since laser absorption spectrophotometry exhibits substantial errors in detecting low-concentration COD, laser-induced fluorescence spectroscopy is adopted for the precise quantification of trace-level COD. By integrating these two laser-based approaches, a spectroscopic COD detection system has been developed that simultaneously records absorbance after the laser passes through the sample and quantifies fluorescence intensity perpendicular to the beam with an image sensor, thereby achieving comprehensive COD analysis. Laboratory validation using COD standard solutions demonstrated relative errors below 11% across the concentration range of 2–220 mg/L. Further application to natural water samples confirmed that the integrated laser absorption–fluorescence spectroscopy approach achieves wide-range COD measurement with high sensitivity, a compact configuration, and rapid response, demonstrating strong potential for real-time online water quality monitoring.

Abstract Understanding preferential evaporation in multi-component fuel sprays is critical for optimizing combustion efficiency and reducing emissions in internal combustion engines. This study focuses on the development of a novel approach that allows for the simultanous detailed characterization of the Sauter Mean Diameter (SMD) and relative ethanol/isooctane volume fraction to elucidate the mechanisms governing preferential evaporation in binary fuel mixtures. This is achieved by combining Planar Droplet Sizing (PDS), a technique based on the ratio between the laser-induced fluorescence (LIF) signal of Nile red-doped fuel and the elastic scattering signal, with a two-color-LIF approach. As Nile red is a solvatochromic dye, i.e., it exhibits a shift in its fluorescence signal with changes in solvent polarity and temperature, the mole fraction of ethanol and isooctane in the spray can be determined, if the spray temperature is known. We performed extensive calibration on various Nile red-doped fuel mixtures in a heated cuvette, as well as in a droplet generator. Further, we minimized morphology-dependent resonance (MDR) effects in the LIF signal of the spray by the selection of spectral filters designed to cover all measured temperatures and concentrations. We found that in the ethanol spray temperatures decrease toward the spray edge. For the fuel-mixed samples, this coincides with a smaller overall SMD and a shift in the ethanol volume fraction in this region.

Abstract We propose a method to perform accurate temperature measurements using laser-induced fluorescence (LIF). We use a sCMOS color camera and a two-dye solution consisting of RuPhen and fluorescein, excited at 450 nm . By varying the relative concentration of the dyes, we can tune the temperature sensitivity of the color channels. This enables a robust laser power correction, reducing the effects of experimental noise compared to the convectional ratiometric approach. Furthermore, the overall temperature sensitivity is only slightly lower compared to that of the temperature-sensitive dye, which is not the case if a ratiometric analysis is performed. We demonstrate the capabilities of our method using a benchtop setup with precisely controlled temperatures. Our error analysis shows that an accuracy better than 0.5 $$^\circ C$$ ∘ C can be achieved. The correction method can be applied to other fluorescence measurement techniques, including pressure-sensitive paints (PSPs).

Non-equilibrium plasma-assisted ammonia synthesis is investigated through enhanced active species production with ferroelectric discharge. Time-resolved in-situ diagnostics of femtosecond two-photon absorption laser-induced fluorescence, coherent anti-Stokes Raman scattering, and laser absorption spectroscopy, as well as optical emission spectroscopy, were conducted to probe the key intermediate species, such as H and N radicals as well as N2(ν), ions, and NH3 to achieve better understanding of non-equilibrium energy transfer and ammonia formation. The results reveal that ferroelectric discharge improved ammonia yield by four times. Results also show that ferroelectrics not only enhanced ions (N2+) production, radicals (N, H) number density, but also increased the N2 vibrational temperature. Further plasma modeling identified the couplings between elevated radical and ion production and enhanced vibrational excitation reactions, e.g., N + H2(ν)→NH + H, N2(ν)+H → NNH, N2+ + H2 → H + N2H+, and N2H++e→NH + N, facilitated by ferroelectric discharge. These findings provide critical insight into the mechanism of ferroelectric plasma catalysis and highlight their potential in advancing energy-efficient chemical synthesis.

The stability and dynamics of flows past axisymmetric bubble-shaped rigid bluff bodies have been numerically and experimentally investigated. Motivated by the shapes of bubbles rising in quiescent liquids the bluff bodies were modelled as spherical and elliptical caps. The geometries are characterised by their aspect ratio, $\chi$ , defined as the ratio of the height of the bubble to the base radius, which is varied from $0.2$ to $2.0$ . Linear stability analyses were carried out on axisymmetric base flow fields subject to three-dimensional perturbations. As observed in earlier studies on bluff-body wakes, the primary bifurcation is stationary, followed by an oscillatory secondary bifurcation, with the leading global mode corresponding to azimuthal wavenumber $m = 1$ . The domain of stability is found to increase with aspect ratio for both of the geometries considered in the present study. The critical Reynolds number corresponding to the primary bifurcation is found to be independent of the aspect ratio when re-scaled using the extent of the recirculation region and the maximum of the reverse-flow velocity as the length and velocity scales, respectively. The wake flow features were characterised experimentally using laser-induced fluorescence and particle-image-velocimetry techniques. It is observed that the flow has a planar symmetry following the primary bifurcation, which is retained beyond the secondary bifurcation. The experimentally measured wavelengths and frequencies are in excellent agreement with the results obtained from global stability analyses. These observations were further corroborated using direct numerical simulations of the three-dimensional flow field. The critical Reynolds numbers corresponding to both primary and secondary bifurcations, and the dominant modes obtained using proper orthogonal decomposition of the experimentally measured velocity fields, are found to agree well with the global mode shapes and numerically computed flow fields.

The spatial organisation of a passive scalar plume originating from a point source in a turbulent boundary layer is studied to understand its meandering characteristics. We focus shortly downstream of the isokinetic injection ( $1.5\leqslant x/\delta \leqslant 3$ , $\delta$ being the boundary-layer thickness) where the scalar concentration is highly intermittent, the plume rapidly meanders and breaks up into concentrated scalar pockets due to the action of turbulent structures. Two injection locations were considered: the centre of the logarithmic region and the wake region of the boundary layer. Simultaneous quantitative acetone planar laser-induced fluorescence and particle image velocimetry were performed in a wind tunnel, to measure scalar mixture fraction and velocity fields. Single- and multi-point statistics were compared with established works to validate the diagnostic novelties. Additionally, the spatial characteristics of plume intermittency were quantified using ‘blob’ size, shape, orientation and mean concentration. It was observed that straining, breakup and spatial reorganisation were the primary plume-evolution modes in this region, with little small-scale homogenisation. Further, the dominant role of coherent vortex motions in plume meandering and breakup was evident. Their action is found to be the primary mechanism by which the injected scalar is transported away from the wall in high concentrations (‘large meander events’). Strong spatial correlation was observed in both instantaneous and conditional fields between the high-concentration regions and individual vortex heads. This coherent transport was weaker for wake injection, where the plume only interacts with outer vortex motions. A coherent-structure-based mechanism is suggested to explain these transport mechanisms.

Abstract Reducing greenhouse gas emissions and achieving carbon neutrality require enhancing spark-ignition engine efficiency and compatibility with renewable fuels. However, electrode wear of spark plugs presents a significant challenge in hydrogen-fueled spark-ignition internal combustion engines. Such excessive wear increases the total cost of ownership and may delay the introduction of such lowemission transportation alternatives. Hence, understanding the interaction between spark discharges and the electrodes to reveal the mechanisms of such wear is crucial. Unlike conventional, ex-situ long-term tests, laser-induced fluorescence (LIF) can assess the wear process during the spark discharges by detecting the target species from the electrodes with high temporal resolution. In this work, spatiotemporal characteristics of gas phase nickel atoms originated from nickel-based alloy spark plug electrodes are performed with two-dimensional planar LIF in elevated pressures. A higher intensity and an earlier peak of laser-induced nickel fluorescence signal are observed under higher pressure. The spatial distribution of nickel atoms within the electrodes gap is observed to be different at varied pressures. Lengthening the dwell time, i.e. charging of the coil between DC spark discharges, and thus increasing the energy of sparks can significantly increase the loss of material. Similarly, increasing the peak current of AC sparks results in a higher power of spark discharges and thus increasing the removal of material. Moreover, the low signal intensity in pure nitrogen indicates that the existence of oxygen enhances the evaporation process and accelerates the erosion of the electrodes. The unique experimental data of electrode wear provides valuable insights not only into the development of next-generation ignition systems for renewable fuels, but also other aspects involving the interactions between the gas discharges and the electrodes, such as spark nanoparticle generation.