Quantitative Measurement of Fluorescent Layers with Respect to Spatial Thickness Variations and Substrate Properties

2020 ◽  
Vol 74 (4) ◽  
pp. 439-451
Author(s):  
Philipp Holz ◽  
Christoph Pönisch ◽  
Albrecht Brandenburg
Keyword(s):  
Manufacturing Industry ◽  
Quantitative Measurement ◽  
Fluorescence Emission ◽  
Fluorescence Analysis ◽  
Thin Layers ◽  
Fluorescence Signal ◽  
Functional Coatings ◽  
Custom Made ◽  
Substrate Properties ◽  
Thickness Variations

Imaging fluorescence spectroscopy proves to be a fast and sensitive method for measuring the thickness of thin coatings in the manufacturing industry. This encouraged us to systematically study, theoretically and experimentally, parameters that influence the fluorescence of thin layers. We analyzed the fluorescence signal as a function of the scattering and reflectance properties of the sample substrate. In addition, we investigated effects of the layer properties on fluorescence emission. A ray-tracing software is used to describe the influence of these parameters on the fluorescence emission of thin layers. Experiments using a custom-made system for imaging fluorescence analysis verify the simulations. This work shows a factor five variation of fluorescence intensity as a function of the reflectance of the sample substrate. Simulations show variations by a factor of up to eight for samples with different surface roughness. Results on tilted samples indicate a significant increase of the detected fluorescence signal, for fluorescent droplets on reflective substrates, if illuminated and coaxially observed at angles greater than 25°. These findings are of utmost relevance for all applications which utilize the fluorescence emission to quantify thin layers. These applications range from in-line lubricant monitoring in press plants to monitoring of functional coatings in medical technology and the detection of filmic contaminations.

scholarly journals Functional Antimicrobial Surface Coatings Deposited onto Nanostructured 316L Food-Grade Stainless Steel

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 1055
Author(s):  
Gonzalez A. S. ◽  
Riego Á. ◽  
Vega V. ◽  
García J. ◽  
Galié S. ◽  
...  
Keyword(s):  
Stainless Steel ◽  
316L Stainless Steel ◽  
Electrochemical Techniques ◽  
Functional Materials ◽  
Atomic Layer ◽  
Thin Layers ◽  
Nanoporous Structure ◽  
Stainless Steel Surface ◽  
Functional Coatings ◽  
Food Grade

In our study, we demonstrated the performance of antimicrobial coatings on properly functionalized and nanostructured 316L food-grade stainless steel pipelines. For the fabrication of these functional coatings, we employed facile and low-cost electrochemical techniques and surface modification processes. The development of a nanoporous structure on the 316L stainless steel surface was performed by following an electropolishing process in an electrolytic bath, at a constant anodic voltage of 40 V for 10 min, while the temperature was maintained between 0 and 10 °C. Subsequently, we incorporated on this nanostructure additional coatings with antimicrobial and bactericide properties, such as Ag nanoparticles, Ag films, or TiO2 thin layers. These functional coatings were grown on the nanostructured substrate by following electroless process, electrochemical deposition, and atomic layer deposition (ALD) techniques. Then, we analyzed the antimicrobial efficiency of these functionalized materials against different biofilms types (Candida parapsilosis, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Staphylococcus epidermidis). The results of the present study demonstrate that the nanostructuring and surface functionalization processes constitute a promising route to fabricate novel functional materials exhibiting highly efficient antimicrobial features. In fact, we have shown that our use of an appropriated association of TiO2 layer and Ag nanoparticle coatings over the nanostructured 316L stainless steel exhibited an excellent antimicrobial behavior for all biofilms examined.

The Investigation of Thin Protecting Layers on Roughened Galvanized Steel Surfaces Produced by Different Coating Methods

2008 ◽  
Vol 589 ◽  
pp. 433-438 ◽  
Author(s):  
Péter Németh ◽  
Ágnes Csanády ◽  
Katalin Papp ◽  
Anna C. Pintér ◽  
László Szabó ◽  
...  
Keyword(s):  
Thickness Distribution ◽  
Thin Layers ◽  
Galvanized Steel ◽  
Photoemission Spectroscopy ◽  
Force Microscopy ◽  
Atomic Force ◽  
Coating Methods ◽  
Chemical States ◽  
Steel Surfaces ◽  
Thickness Variations

Protective, chromate substitute thin layers on roughened galvanized surfaces produced at OCAS (Arcelor, Belgium) were characterized and compared using Scanning Electron Microscopy (SEM+EDS), Atomic Force Microscopy (AFM), Nanoindentation and X-ray Photoemission Spectroscopy (XPS). EDX maps, line scans and point analyses obtained at various places of the surfaces have shown differences between the CVD and silane nanolayers in the matter of thickness distribution and composition. At cross-section specimens the thickness of the layers could be shown. The hardness differences caused by layer thickness variations are hard to follow by nanoindentation as the penetration depth of the indenter is much larger than the thickness of the coatings. XPS measurements can distinguish between the chemical states of silicon in CVD and silane coatings.

A study of the corrosion of polymethyl methacrylate coated rebar using glancing angle X-ray absorption near edge spectroscopy

CORROSION ◽  
10.5006/3912 ◽  
2021 ◽  
Author(s):  
Arthur Situm ◽  
Xiaoxuan Guo ◽  
Burke Barlow ◽  
Bao Guo ◽  
Ian Burgess ◽  
...  
Keyword(s):  
Polymethyl Methacrylate ◽  
Polymer Coating ◽  
Steel Corrosion ◽  
Corrosion Products ◽  
Thin Layers ◽  
Fluorescence Signal ◽  
X Rays ◽  
X Ray ◽  
Glancing Angle ◽  
X Ray Absorption

Polymer coatings can be used to mitigate the corrosion of steel in high chloride environments. Obtaining speciation information from thin corrosion layers can be important for understanding corrosion mechanisms, including polymer coating failure. This study outlines the effectiveness of collecting glancing angle X-ray absorption near edge spectroscopy (GA-XANES) spectra at the Fe K-edge to obtain chemical speciation information at the polymer-steel interface without removal of the polymer film. The depth of penetration of the incident X-rays can be altered by changing the incidence angle, allowing for more fluorescence signal from corrosion products to be detected relative to the Fe metal fluorescence signal in GA-XANES spectra. This study demonstrates the use of GA-XANES to study thin layers of steel corrosion and obtain depth profile information of steel corrosion products beneath a polymethyl methacrylate polymer coating.

Origami-Layer-Jamming Deployable Surgical Retractor With Variable Stiffness and Tactile Sensing

2020 ◽  
Vol 12 (3) ◽  
Author(s):  
Hritwick Banerjee ◽  
Tai Kai Li ◽  
Godwin Ponraj ◽  
Senthil Kumar Kirthika ◽  
Chwee Ming Lim ◽  
...  
Keyword(s):  
Negative Pressure ◽  
Surgical Complications ◽  
Variable Stiffness ◽  
Tactile Sensor ◽  
Interaction Force ◽  
Thin Layers ◽  
Medical Applications ◽  
Conductive Ink ◽  
Custom Made ◽  
Near Future

Abstract Origami-based flexible, compliant, and bio-inspired robots are believed to permit a range of medical applications within confined environments. In this article, we experimentally demonstrated an origami-inspired deployable surgical retractor with the controllable stiffness mechanism that can facilitate safer instrument–tissue interaction in comparison to their rigid counterparts. When controllable negative-pressure is applied to the jammed origami retractor module, it becomes more rigid, increasing its strength. To quantify origami-modules strength further, we demonstrated performances of retractor based on the Daler–Rowney Canford paper (38 grams per square meter (gsm)) and sandpaper of 1000 grit. Experiments on the proposed retractor prototype elucidated sandpaper-based retractor can outperform paper-38-gsm retractor for facelift incision with the width of more than 9 cm. Though 38 gsm Canford paper comprised of thin layers, 16 times lesser in thickness than sandpaper, experiments proved its comparable layer jamming (LJ) performance. We leverage the advantage of the LJ mechanism to tune retractor stiffness, allowing the instrument to hold and separate a facelift incision to mitigate the likelihood of surgical complications. The retractor is equipped with a custom-made printed conductive ink-based fabric piezoresistive tactile sensor to assist clinicians with tissue-retractor interaction force information. The proposed sensor showed a linear relationship with the applied force and has a sensitivity of 0.833 N−1. Finally, cadaver experiments exhibit an effective origami-inspired surgical retractor for assisting surgeons and clinicians in the near future.

Grazing Incidence X-Ray Fluorescence Analysis using Synchrotron Radiation

1991 ◽  
Vol 35 (B) ◽  
pp. 795-806
Author(s):  
Atsuo Iida
Keyword(s):  
Synchrotron Radiation ◽  
Elemental Concentration ◽  
Depth Distribution ◽  
Fluorescence Analysis ◽  
Grazing Incidence ◽  
Material Surface ◽  
Fluorescence Signal ◽  
Elemental Distribution ◽  
X Ray ◽  
Glancing Angle

AbstractThe X-ray fluorescence analysis of a trace element under a grazing incidence condition has been developed using synchrotron radiation. The interference effect plays an important role for determining the depth distribution of the elemental concentration. The elemental distribution above, on or below the material surface has been studied. The glancing angle dependence of the X-ray fluorescence signal around the critical angle strongly reflects the elemental distribution, and can be used to determine the position of the element of interest.

Polypyrrole/Graphene Quantum Dot Composites as a Sensor Media for Epinephrine

2020 ◽  
Vol 20 (7) ◽  
pp. 4005-4010 ◽  
Author(s):  
Thi Hoa Le ◽  
Dal Ho Lee ◽  
Ji Hyeon Kim ◽  
Sang Joon Park
Keyword(s):  
Quantum Dot ◽  
Photoinduced Electron Transfer ◽  
Surface Passivation ◽  
Fluorescence Emission ◽  
Fluorescence Signal ◽  
Serum Samples ◽  
Strong Fluorescence ◽  
Electron Transfer Process ◽  
Graphene Quantum Dot ◽  
Amine Groups

In this paper, we discuss a new biosensor for simple and rapid detection of epinephrine (EP) based on polypyrrole/graphene quantum dot (PPy/GQD) composites. Presence of amine groups on the PPy backbone leads to surface passivation of GQDs. As a result, the composites exhibit strong fluorescence emission, which can be up to three times that of pristine GQDs. In neutral to alkaline solution, the EP on the surface of PPy/GQD composites is converted to a quinone, which triggers the fluorescence quenching of PPy/GQD composites via a photoinduced electron transfer process. Hence, the concentration of EP can be effectively monitored by measuring the variation in the fluorescence signal of PPy/GQD composites. The quenched fluorescence intensity of PPy/GQDs was proportional to the concentration of EP (0.7–400 μM). We used our method to determine the concentration of EP in human serum samples and obtained satisfactory results.

Endoscopic fluorescence visualization of 5-ALA photosensitized central nervous system tumors in the neural tissue transparency spectral range

2014 ◽  
Vol 3 (2) ◽  
Author(s):  
Maxim Loshchenov ◽  
Petr Zelenkov ◽  
Aleksandr Potapov ◽  
Sergey Goryajnov ◽  
Alexandr Borodkin
Keyword(s):  
Real Time ◽  
Color Image ◽  
Protoporphyrin Ix ◽  
Thin Layers ◽  
Fluorescence Signal ◽  
Excitation Light ◽  
Fluorescence Image ◽  
Diagnostic Quality ◽  
Real Time Image ◽  
Time Image

AbstractBackground:Fluorescence endoscopy systems for photosensitizer visualization have proved to be powerful tools for highlighting malignant tumor boundaries as well as detecting small, visually non-detectable, residual parts during photodynamic therapy. Most of these devices use excitation wavelengths in the blue visual spectrum range (405 nm) which limits the penetration depth in the tissue.Objective:In the study being presented in this article an apparatus and a method were developed for performing endoscopic fluorescence diagnostics of photosensitizer accumulation using excitation light in the red part of visual spectrum, i.e., 635 nm, which allows not only a deeper penetration of light into the tissue but also better scanning abilities and a higher diagnostic quality. Additionally, 635-nm radiation can penetrate thin layers of blood which appear during surgery.Material and methods:In order to use 635-nm excitation, a specially designed video endoscopy system was developed. The key feature of the video system is a dual camera video receiver where one sensitive B/W camera receives the fluorescence signal and a color camera receives the real-time image in natural colors during navigation. The software developed for the apparatus allows overlaying of the video output of fluorescence image on top of the conventional color image in real-time. The experimental setup and method were tested on Intralipid-based phantoms with protoporphyrin IX (PpIX) concentrations of 0.5–5 mg/kg, and then on two patients during surgery. The patients were administered 20 mg/kg 5-ALA photosensitizer 3 h before surgery according to standard practice of 5-ALA in neurosurgery.Results:The experiments demonstrate that the designed setup is sensitive enough for clear visualization of biological concentrations of PpIX in both phantoms with 0.5 mg/kg PpIX and previously photosensitized tissues of patients.Conclusion:Further prospective validation is needed to translate the results to clinical practice.

scholarly journals ENHANCED FLUORESCENCE IMAGING WITH DMSO-MEDIATED OPTICAL CLEARING

2010 ◽  
Vol 03 (03) ◽  
pp. 153-158 ◽  
Author(s):  
SANJEEV KARMA ◽  
JAMES HOMAN ◽  
CHARLES STOIANOVICI ◽  
BERNARD CHOI
Keyword(s):  
Fluorescence Emission ◽  
Model Systems ◽  
In Vivo Studies ◽  
In Vivo Model ◽  
Fluorescence Signal ◽  
Optical Clearing ◽  
Treated Site

Recent studies have demonstrated that topical application of glycerol on intact skin does not affect its optical scattering properties. Investigators from our research group recently revisited the use of dimethyl sulfoxide (DMSO) as an agent with optical clearing potential. We address the use of optical clearing to enhance quantitation of subsurface fluorescence emission. We employed both in vitro and in vivo model systems to study the effect of topical DMSO application on fluorescence emission. Our in vitro experiments performed on a tissue-simulating phantom suggest that DMSO-mediated optical clearing enables enhanced characterization of subsurface fluorophores. With topical DMSO application, a marked increase in fluorescence emission was observed. After 30 min, the fluorescence signal at the DMSO-treated site was 9× greater than the contralateral saline-treated site. This ratio increased to 13× at 105 min after agent application. In summary, DMSO is an effective optical clearing agent for improved fluorescence emission quantitation and warrants further study in preclinical in vivo studies. Based on outcomes from previous clinical studies on the toxicity profile of DMSO, we postulate that clinical application of DMSO as an optical clearing agent, can be performed safely, although further study is warranted.

scholarly journals Calibration of systems for quantitative fluorescence analysis of thin layers

2019 ◽  
Vol 27 (24) ◽  
pp. 34559
Author(s):  
Philipp Holz ◽  
Albrecht Brandenburg
Keyword(s):  
Fluorescence Analysis ◽  
Thin Layers ◽  
Quantitative Fluorescence
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