Using an Optical Reflectometer to Measure Caries Lesion Activity on Enamel

Background: Specular reflection can be used to quantify dental erosion, and might also provide similar results for caries. This study assessed the possibility of using specular reflection intensity (SRI; quantitative lesion activity assessment) to measure the progression of initial enamel caries lesions. Methods: Two hundred native enamel specimens and flat ground enamel specimens (n=100 each) were subjected to a 4-species biofilm caries model during 2, 4, 6, 8, and 10 weeks (n=20 each), to induce ‘active’ enamel caries lesions. Afterwards, to induce ‘inactive’ lesions, all specimens were continuously remineralized and brushed twice daily for 2, 4, 6, 8, and 10 weeks. Change in specular reflection intensity (%SRI), visual caries detection (ICDAS) and visual caries severity assessment were performed for all active lesions and during the remineralization phase. Scanning electron microscopy (SEM) images were taken for qualitative analysis. Results: For active lesions, %SRI dropped from 100% to about 80% in native enamel, and to about 15% in polished enamel. Remineralization/brushing increased %SRI in native enamel, but not in polished enamel. The comparison with visual caries scores yielded a better linear relationship of %SRI with early enamel lesion where caries was induced for up to 6 weeks. Conclusion: The use of the optical reflectometer for the assessment of caries lesion activity seemed to work better for early caries lesions and for polished specimens.

Study The Relationship of Thermal Reflection Intensity with Its Height and Thickness

Surface heat inversion (SHI) is important in determining the spread of pollutants in the lower part of the troposphere. This paper presents the relationship between heat inversion intensity and its height and thickness using the daily radiosonde data (midnight) of the period from (2013-2014) obtained from the Iraq Meteorological Organization and Seismology (IMOS). The results of the study were that heat inversion intensity increases with the increase in height in winter, summer, and autumn, during the spring, so there is no relationship. The relationship of heat inversion thickness with intensity is linear in spring, summer, and autumn, but inverse in winter.

Optical and magnetic properties of particles containing guanine in strong basic solution

Guanine based particle is one of very efficient material to control light especially near the surface of animal body. Past studies reported that platelets of anhydrous guanin crystal are utilized by living creatures, and they can change their colour and light reflection intensity when the arrangement of platelets. Guanine has relatively high reflective index and its particle can exhibit a unique optical property. Under higher pH which can be provided by a high concentration of NaOH aqueous solution, guanine molecules formed a sodium salt particle which contain guanine. Here this work presents that particles containing guanine in basic aqueous solution with NaOH exhibited very strong shining and light reflection switching by magnetic fields. In addition, adding an extracted solution of a fish iridophore enhanced the formation of intensively light reflecting guanine particles floating in a strong basic solution.

Imaging Scatterometry with Extrapolation of Missing BRDF Data for Materials Used in Laser Material Processing

Imaging scatterometry is a method for determining the reflection distribution based on bidirectional reflectance distribution function (BRDF) measurements. However, it has a well-known limitation that results obtained by imaging scatterometry for small illumination angles are practically useless. Therefore, we propose an approach for reconstruction of the reflection distribution based on a series of measurements at different illumination angles and extrapolation of the missing results to overcome this limitation. The developed algorithm was validated using bidirectional transmittance distribution function (BTDF) measurements. The BRDF measurements were carried out for materials that are commonly used in laser material processing, i.e. substrates and functional coatings. The obtained data were subsequently used to determine the total reflection intensity from all considered materials, which were characterized by reconstructed distributions.

Strong Coupling between Tamm and Surface Plasmons for Advanced Optical Bio-Sensing

The total internal reflection ellipsometry method was used to analyse the angular spectra of the hybrid Tamm and surface plasmon modes and to compare their results with those obtained using the conventional single SPR method. As such type of measurement is quite common in commercial SPR devices, more detailed attention was paid to the analysis of the p-polarization reflection intensity dependence. The conducted study showed that the presence of strong coupling in the hybrid plasmonic modes increases the sensitivity of the plasmonic-based sensors due to the reduced losses in the metal layer. The experimental results and analysis of the optical responses of three different plasmonic-based samples indicated that the optimized Tamm plasmons ΔRp(TP) and optimized surface plasmons ΔRp(SP) samples produce a response that is about five and six times greater than the conventional surface plasmon resonance ΔRp(SPR) in angular spectra. The sensitivity of the refractive index unit of the spectroscopic measurements for the optimized Tamm plasmon samples was 1.5 times higher than for conventional SPR, while for wavelength scanning, the SPR overcame the optimized TP by 1.5 times.

Image-based Perceptual Editing: Leather “Authenticity” as a Case Study

Traditionally, the appearance of an object in an image is edited to elicit a preferred perception. However, the editing method might be arbitrary and might not consider the human perception mechanism. In this study, the authors explored image-based leather “authenticity” editing using an estimation model that considers a perception mechanism derived in their previous work. They created leather rendered images by emphasizing or suppressing image properties corresponding to the “authenticity.” Subsequently, they performed two subjective experiments, one using fully edited images and another using partially edited images whose specular reflection intensity was constant. Participants observed the leather rendered images and evaluated the differences in the perception of “authenticity.” The authors found that the “authenticity” perception could be changed by manipulating the intensity of specular reflection and the texture (grain and surface irregularity) in the images. The results of this study could be used to tune the properties of images to make them more appealing.