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Estimation of the Lyman- <i>α</i> signal of the EFILE diagnostic under static or radiofrequency electric field in vacuum
摘要： The electric field induced Lyman-α emission diagnostic aims to provide a non intrusive and precise measurement of the electric field in plasma, using a beam of hydrogen atoms prepared in the metastable 2s state. The metastable particles are obtained by means of a proton beam extracted from a hydrogen plasma source, and neutralised by interaction with vaporised caesium. When a 2s atom enters a region where an electric field is present, it undergoes a transition to the 2p state (Stark mixing). It then quickly decays to the ground level, emitting Lyman-α radiation, which is collected by a photomultiplier. The s→p transition rate is proportional to the square of the magnitude of the electric field, and depends on the field oscillation frequency (with peaks around 1 GHz). By measuring the intensity of the Lyman-α radiation emitted by the beam it is possible to determine the magnitude of the field in a defined region. In this work, an analysis of the behaviour of the diagnostic under static or radiofrequency electric field is presented. Electric field simulations obtained with a finite element solver of Maxwell equations, combined with theoretical calculations of the Stark mixing transition rate, are used to develop a model for the interpretation of photomultiplier data. This method shows good agreement with experimental results for the static field case, and allows to measure the field magnitude for the oscillating case.
关键词： Stark effect,plasma diagnostics,electric field measurement,electromagnetic simulations
更新于2025-09-19 17:15:36
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Metasurfaces for Advanced Sensing and Diagnostics
摘要： Interest in sensors and their applications is rapidly evolving, mainly driven by the huge demand of technologies whose ultimate purpose is to improve and enhance health and safety. Different electromagnetic technologies have been recently used and achieved good performances. Despite the plethora of literature, limitations are still present: limited response control, narrow bandwidth, and large dimensions. MetaSurfaces, artificial 2D materials with peculiar electromagnetic properties, can help to overcome such issues. In this paper, a generic tool to model, design, and manufacture MetaSurface sensors is developed. First, their properties are evaluated in terms of impedance and constitutive parameters. Then, they are linked to the structure physical dimensions. Finally, the proposed method is applied to realize devices for advanced sensing and medical diagnostic applications: glucose measurements, cancer stage detection, water content recognition, and blood oxygen level analysis. The proposed method paves a new way to realize sensors and control their properties at will. Most importantly, it has great potential to be used for many other practical applications, beyond sensing and diagnostics.
关键词： MetaSurface,sensors,cancer detection,modeling,medical diagnostics,glucose measurements,design
更新于2025-09-19 17:15:36
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Raman spectroscopic analysis of high molecular weight proteins in solution – considerations for sample analysis and data pre-processing
摘要： This study explores the potential of Raman spectroscopy, coupled with multivariate regression techniques and a protein separation technique (ion exchange chromatography), to quantitatively monitor diagnostically relevant changes in high molecular weight proteins in liquid plasma. Measurement protocols to detect the imbalances in plasma proteins as an indicator of various diseases using Raman spectroscopy are optimised, such that strategic clinical applications for early stage disease diagnostics can be evaluated. In a simulated plasma protein mixture, concentrations of two proteins of identified diagnostic potential (albumin and fibrinogen) were systematically varied within physiologically relevant ranges. Scattering from the poorly soluble fibrinogen fraction is identified as a significant impediment to the accuracy of measurement of mixed proteins in solution, although careful consideration of pre-processing methods allows construction of an accurate multivariate regression prediction model for detecting subtle changes in the protein concentration. Furthermore, ion exchange chromatography is utilised to separate fibrinogen from the rest of the proteins and mild sonication is used to improve the dispersion and therefore quality of the prediction. The proposed approach can be expeditiously employed for early detection of pathological disorders associated with high or low plasma/serum proteins.
关键词： sonication,pre-processing,disease diagnostics,Raman spectroscopy,plasma proteins,ion exchange chromatography,multivariate regression
更新于2025-09-19 17:15:36
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Cell Phone based Colorimetric Analysis for Point-of-Care Settings
摘要： Cell phones show considerable promise for point-of-care (POC) diagnostic procedures because they are accessible, connected, and computationally powerful. Cell phone image processing methods are being developed for the detection and quantification of a wide range of targets, employing methods from microscopy to fluorescence techniques. However, most of the lab-based biological and biochemical assays still lack a robust and repeatable cell phone analogue. Existing solutions require external smartphone hardware to obtain quantitative results, imposing a design tradeoff between accessibility and accuracy. Here, we develop a cell phone imaging algorithm that enables analysis of assays that would typically be evaluated via spectroscopy. The developed technique uses the saturation parameter of hue-saturation-value color space to enable POC diagnosis. Through the analysis of over 10,000 images, we show that the saturation method consistently outperforms existing algorithms under a wide range of operating field conditions. The performance improvement is also proven analytically via the mathematic relationship between the saturation method and existing techniques. The method presented here is a step forward towards the development of POC diagnostics by reducing the required equipment, improving the limit of detection (LOD), and increasing the precision of quantitative results.
关键词： Spectroscopy,Cell Phone Imaging,Point-of-Care Diagnostics,Colorimetry
更新于2025-09-19 17:15:36
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Study of the IR Spectra of the Saliva of Cancer Patients
摘要： Feasibility has been demonstrated in principle for the diagnosis of lung and breast cancer by subjecting saliva to Fourier transform IR spectroscopy. Statistically significant differences in the saliva of lung cancer patients are seen at 1070–1240 cm–1, while significant differences are seen throughout the entire range for breast cancer patients. The I1398/1454 and I1240/1310 ratios were determined and found to be statistically reliable for detecting cancer pathology. Correlations were found for the intensities of the absorption bands in these IR spectra with nonspecific biochemical saliva parameters, which generally characterize greater intoxication as well as suppression of the systems for antioxidant protection and the immune response. A promising research trend involves the use of the IR spectroscopy of saliva for monitoring treatment and cancer recurrence.
关键词： Fourier transform IR spectroscopy,saliva,diagnostics,oncology
更新于2025-09-19 17:15:36
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Towards an optical diagnostic system for otitis media using a combination of otoscopy and spectroscopy
摘要： An improved method, where conventional otoscope investigation of human suspicious otitis media is combined with diffuse reflectance spectroscopy and gas in scattering media absorption spectroscopy (GASMAS) is being developed. Otitis media is one of the most common infectious diseases in children, whose Eustachian tube connecting the middle ear with the nasal cavity is more horizontal than for adults, which leads to impaired fluid drainage. At present, the use of an otoscope to visually observe possible changes in the tympanic membrane appearance is the main diagnostics method for otitis media. Inaccurate diagnosis related to similar symptoms, and the difficulty for small children to describe the condition experienced, frequently leads to over-prescription of antibiotics and alarming increase in bacterial resistance development. More accurate diagnostic methods are highly desirable. Diffuse reflectance spectroscopy is a non-invasive quantitative spectroscopic technique that enables to objectively quantify changes in the hemoglobin content of the tympanic membrane related to inflammation. If an infection is present, the ventilatory function of the Eustachian tube is frequently impaired and the middle-ear cavity will be filled with fluid. GASMAS, a non-invasive detection method, can non-invasively determine if gas is replaced by fluid in the middle-ear cavity.
关键词： otitis media,otoscope,diffuse reflectance spectroscopy,diagnostics,GASMAS,ear infection
更新于2025-09-19 17:15:36
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Single-shot electrons and protons time-resolved detection from high-intensity laser–solid matter interactions at SPARC_LAB
摘要： Laser–plasma interactions have been studied in detail over the past twenty years, as they show great potential for the next generation of particle accelerators. The interaction between an ultra-intense laser and a solid-state target produces a huge amount of particles: electrons and photons (X-rays and γ-rays) at early stages of the process, with protons and ions following them. At SPARC LAB Test Facility we have set up two diagnostic lines to perform simultaneous temporally resolved measurements on both electrons and protons.
关键词： high power laser,TNSA,electron diagnostics,proton diagnostics,single-shot diagnostics,time-of-flight detector
更新于2025-09-19 17:13:59
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The distribution of OH in surface micro-discharge with different electrode widths by laser-induced fluorescence
摘要： Cold atmospheric plasma has been successfully applied in the field of biomedicine. One of the most pressing challenge is the development of plasma devices, for example, large-area application in wound healing. Surface micro-discharge device is one new type of dielectric barrier discharge design with desirable plasma features, such as homogeneity over a large surface area. In this study, two devices with electrode width varying from 0.25 to 1.00 mm were fabricated. The contribution focuses on the impact of the hexagonal mesh electrode width on the degree of uniformity of hydroxyl (OH) radicals in the downstream region and the OH transport efficiency. Accordingly, OH radicals were measured as an indicator by laser-induced fluorescence. Steady state measurements of OH perpendicular to the dielectric surface demonstrated that narrow electrode width could not offer a high degree of uniformity, and will reduce the transport efficiency of reactive species.
关键词： Plasma diagnostics - interferometry, spectroscopy and imaging,Plasma diagnostics - high speed photography
更新于2025-09-19 17:13:59
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Simultaneous measurement of CO and OH in flames using a single broadband, femtosecond laser pulse
摘要： In this short communication, we report simultaneous measurement of CO and OH in flames using a single femtosecond (fs)-duration laser source. Two-photon excitation of CO A 1 (cid:2) ←← X 1 ?+ (3,0), (4,0) and (5,0) bands and single-photon excitation of OH A 2 ?+ ← X 2 (cid:2) (1,0) band are achieved simultaneously using one fs-duration laser pulse near 283 nm. Subsequently, crosstalk-free, laser-induced fluorescence (LIF) emissions are detected from the v’ = 3, 4 and 5 upper vibrational levels of CO in the 200–230 nm region, and (1,1) and (0,0) bands of OH near the 310-nm region. A detailed spectroscopic investigation of CO in a gas cell is followed by simultaneous detection of CO and OH in C 2 H 4 /air flames. The measured CO and OH profiles as a function of flame equivalence ratio agree well with equilibrium calculations. The present study extends the applicability of broadband fs-LIF imaging of OH in flames, and reveal an alternate method to obtain heat release rate in turbulent flames via simultaneous OH and CO measurements.
关键词： Femtosecond diagnostics,Carbon monoxide,Laser-induced fluorescence,Hydroxyl radical
更新于2025-09-19 17:13:59
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Study of laser-driven magnetic fields with a continuous wave Faraday rotation diagnostic
摘要： Magnetic ?elds driven by a laser in coil targets were studied for laser energies of (cid:2)25 J and two pulse durations of 2.8 ns and 70 ps. Axial magnetic ?elds in the coils were measured by continuous wave Faraday rotation diagnostics. The diagnostics indicated magnetic ?elds of 6–14 T in the coil and currents of 10–20 kA. Magnetic ?elds were compared for similar laser targets, focusing conditions, and laser energies. A 30-times increase in the intensity of the laser beam by reducing the pulse duration resulted in an increase in the magnetic ?eld and current by a factor of 2. The relaxation time of the magnetic pulse was on the sub-microsecond scale.
关键词： coil targets,magnetic field measurement,laser-driven magnetic fields,pulse duration,Faraday rotation diagnostics
更新于2025-09-19 17:13:59