Differences In Light Transmission Research Articles

A Quantitative Method to Measure Oil-Separation Properties of Lubricating Greases

The oil-separation properties of lubricating greases are responsible for transporting base oil to the bearing contacts. Therefore, a good understanding of these properties is necessary to predict grease life based on physical grease properties. Currently, oil separation for small, aged grease samples collected from bearings, is studied using so-called maintenance tools. These tools give qualitative insight into the grease properties, e.g., increases or decreases in oil separation after ageing of the grease. In this work, a quantitative, lab-scale method to study oil separation is presented. Using this method, the amount of base oil transferred from a grease sample to a piece of blotting paper is measured based on the difference in light transmission through the oil stain and the dry paper. Translation of transmitted light intensity to oil concentration is accomplished using a modified Lambert-Beer’s law. This enables the determination of the instantaneous bleed rate and oil content. In combination with a physical model, this method can help to improve the understanding of the driving forces behind oil separation, e.g., the affinity pressure and permeability.

In-Line Gas Sensor Based on the Optical Fiber Taper Technology with a Graphene Oxide Layer

This article investigates the possibilities of gas detection using a tapered optical fiber coated with a graphene oxide layer. Measurement is based on changes in light beam propagation depending on the process of gas absorption to the graphene oxide layer. In this paper, we investigated the light change in a double-clad tapered optical fiber in a wide optical range. We present a special platform constructed for the deposition of additional functional materials that enable the preparation of the sensor module. Our results present differences in light transmission for three different kinds of gasses pure nitrogen, pure hydrogen, and a mixture of propane–butane. Measurements were provided in a wide range of 500 nm–1800 nm to find the most sensitive ages for which we are able to detect mentioned absorption and their interaction with light. Obtained results for pure gasses for which the refractive indices are similar to the air show the greatest changes for the visible range 750 nm–850 nm, and for propane–butane, changes are much visible in the whole investigated range.

Использование поляризационно-интерференционной микроскопии для определения оптических свойств фетальных эритроцитов в тканях

Objective: to evaluate the possibility of using polarization interference microscopy for morphological diagnostics of fetal erythrocytes in tissues. Materials and methods. Blood smears used during the diagnostic and treatment process and histological sections prepared from autopsy material were used. During the diagnosis, a polarization-interference microscope PZO BIOLAR PI with a microphotometric nozzle UPI was used to determine the optical density and the measure of light transmission in erythrocytes. The method of polarization-interference microscopy contributed to the study of optical properties in individual erythrocytes. The optical properties of erythrocytes containing fetal-type hemoglobin and erythrocytes with adult-type hemoglobin were compared. The difference in the composition of the structure of erythrocytes determined the difference in light transmission and refraction. Based on the results of light transmission, the optical density of fetal and adult erythrocytes was calculated. In the conducted study of clinical blood smears, in neonatal patients, 60 measurements of the light transmission coefficient and 60 similar studies were performed in patients of the comparison group - persons older than 18 years. In the study of autopsy material, 120 measurements of the erythrocyte light transmission coefficient were carried out in placental tissue samples (chorionic villi and interstitial space). Results. The optical properties of erythrocytes were determined both in blood smears and in placental tissue preparations. Erythrocytes in blood smears with HbF had an increased light transmission coefficient in relation to the optical properties of erythrocytes with HbA in the control group. During the study of placental tissues, it was revealed that the indicators of the optical density of maternal erythrocytes with HbA in the erythrocytes of the interstitial space differed in higher values of indicators compared with the optical density of fetal erythrocytes with HbF in the vessels of chorionic villi. Conclusion. The determination of differences in the physico-optical properties of erythrocytes with fetal and adult hemoglobins makes it possible to determine the affiliation of erythrocytes both in blood smears and in the interstitial space of the placenta.

Optical Properties of Lentil Seed Coats Using Fiber-Optic Spectroscopy

HighlightsA fiber-optic spectroscopy system was set up and validated for measurement of optical properties of lentil seed coat.Light transmission properties of major lentil seed coat types were measured to evaluate their protective ability.Light transmission was detected mainly in the UVA and visible regions in all seed coat types except zero tannin.The protective abilities differed depending on seed coat type (important in breeding for cotyledon protection).Abstract. The light transmission of 20 lentil genotypes, representing six color classes (black, green, tan, brown grey, and zero tannin) was investigated to determine the degree to which seed coats prevent light transmission and possible photodegradation of cotyledon color. A fiber-optic spectroscopy system was set up for measurement; it consisted a deuterium-halogen light source, spectrometer, fiber-optic incidence and transmission probes, and sample holders. The nadir-aligned transmission spectra were measured in wavelength ranges of 250 to 850 nm. To study variability in light transmission of the different seed coat types, the curves were integrated in three wavelength regions to obtain Cumulative UV Transmission (CUVT, 250 to 400 nm), Cumulative VIS Transmission (CVIST, 401 to 700 nm), and Cumulative NIR Transmission (CNIRT, 701 to 850 nm), respectively. Tests for significant differences in light transmission were then done using analysis of variance (ANOVA) via General Linear Modelling and Posthoc GLM Tukey tests. Results showed that all the seed coat types, except zero tannin, showed no detectable transmission of UV light from 250 to 315 nm. Black seed coats showed detectable transmission from 615 to 850 nm, while other seed coat types transmitted varying percentages of light from 315 to 850 nm. The results of ANOVA showed that there were significant (p<0.05) differences in light transmission properties of the major seed coat types. Keywords: Fiber optics, Lentils, Light transmission, Pulse quality, Spectroscopy, Seed coat.

Features of images of water, ice, snow, objects and a human formed by a hybrid television camera in the near-infrared range

Recently, television cameras operating in the near-infrared range have become increasingly widespread. The advantage of shooting in the short wave infrared range is the ability to observe objects in low light and difficult weather conditions. Such cameras can use hybrid sensors that consist of an infrared photocathode and an electron-sensitive matrix based on silicon in a single vacuum volume. The paper investigates the capabilities of one of the latest samples of a similar camera, created at JSC “NRI Electron”. The images of a human, water, ice, snow and other objects in the wavelength range of 0.95–1.7 microns have been analyzed. The images were taken using a television camera based on a hybrid television infrared sensor, which consists of a photocathode and a silicon charge-coupled device in proximity range to each other in a single vacuum volume. Illumination of the objects in the near-infrared range was produced by a continuous spectrum lamp with a maximum of the detected radiation at a wavelength of 1.55 μm. The authors compared the images obtained in the near-infrared range with the ones obtained in the visible region. An explanation is given for the differences between snow images and water and ice images in the near-infrared range. As an example, the difference in light transmission between the surfaces of materials for diving equipment, such as coated and open cell neoprene, is demonstrated. Due to a significant contrast shown in the near-infrared range by images of various objects on the surface of water and ice, it is possible to create an effective system for searching objects on the water. The paper discusses the advantages of the proposed visual search system compared to other systems, including passive systems and the ones operating in the MWIR and LWIR. The research outlined the prospects of using the new camera for building an effective search system for objects and people on water surfaces

First successful field evaluation of new, one-minute haemozoin-based malaria diagnostic device

BackgroundEarly and accurate diagnosis of malaria is critical to the success of malaria elimination. However, the current mainstay of malaria diagnosis in the field, such as light microscopy and rapid diagnostic tests (RDTs), have limitations due to low parasite density or mutation in diagnostic markers. MethodsWe evaluated an inexpensive, robust, rapid, malaria diagnostic device, called Gazelle, that employs magneto-optical detection to identify haemozoin crystals (Hz) produced by all species of human malaria parasites in infected individuals. A beam of polarised light is passed through the lysed diluted blood sample under the influence of high (~.55T) and low magnetic fields. The difference in light transmission through the sample between the high and low magnetic fields indicates presence of Hz, suggesting possible malarial infection. A total of 300 febrile patients were screened at the malaria clinic of Indian Council of Medical Research-National Institute of Research in Tribal Health (ICMR-NIRTH), Jabalpur, India, from August 2018 to November 2018. Malaria diagnosis was done using four diagnostic methods: Gazelle, light microscopy, RDT, and malaria specific Polymerase Chain Reaction (PCR). Measures of diagnostic accuracy were compared. FindingsOut of 300 febrile patients enroled and tested for the presence of malaria parasites, 262 patient samples were included in the final analysis. The sensitivity and specificity of Gazelle was 98% and 97% in comparison to light microscopy, 82% and 99% to PCR and 78% and 99% to RDT, respectively. The results of the four diagnostic methods were comparable and statistically no significant differences in sensitivity or specificity was observed between these methods. Enhanced diagnostic accuracy of Gazelle in malaria patients with no prior history of malaria treatment was observed in this study. InterpretationThe diagnostic ability of Gazelle was comparable to light microscopy and better than RDTs even in low parasitemia and in presence of pfhrp2/3 deletion mutant parasites. Gazelle may be a novel valuable diagnostic tool in resource poor settings where (i) microscopy is not feasible and (ii) pfhrp2/3gene deleted parasite are present. Its speed, cost-efficiency, and alternative to lack of microscopists makes it an important adjunct in field settings. FundingHemexDx, India.

Laser-driven ion acceleration via target normal sheath acceleration in the relativistic transparency regime

We present an experimental study investigating laser-driven proton acceleration via target normal sheath acceleration (TNSA) over a target thickness range spanning the typical TNSA-dominant regime (∼1 μm) down to below the onset of relativistic laser-transparency (<40 nm). This is done with a single target material in the form of freely adjustable films of liquid crystals along with high contrast (via plasma mirror) laser interaction (∼2.65 J, 30 fs, W cm−2). Thickness dependent maximum proton energies scale well with TNSA models down to the thinnest targets, while those under ∼40 nm indicate the influence of relativistic transparency on TNSA, observed via differences in light transmission, maximum proton energy, and proton beam spatial profile. Oblique laser incidence (45°) allowed the fielding of numerous diagnostics to determine the interaction quality and details: ion energy and spatial distribution was measured along the laser axis and both front and rear target normal directions; these along with reflected and transmitted light measurements on-shot verify TNSA as dominant during high contrast interaction, even for ultra-thin targets. Additionally, 3D particle-in-cell simulations qualitatively support the experimental observations of target-normal-directed proton acceleration from ultra-thin films.

Polarization-independent asymmetric light transmission in all-dielectric photonic structures

We design, optimize and fabricate an all-dielectric photonic structure, having a significant, polarization-independent asymmetry in light transmission for opposite incident wave directions. The device, consisting of a dielectric Bragg mirror topped with a regular grid of micrometer-sized pillars, acting as a diffraction grating, is potentially scalable into industrial production. The light propagation simulation results are confirmed by direct measurement of the difference in light transmission, reaching 0.55 near 780 nm, and exceeding 0.2 over a spectral range spanning from 750 to 820 nm.

Influence of increment thickness on light transmission, degree of conversion and micro hardness of bulk fill composites.

This study evaluated characteristics of light transmission, degree of monomer conversion and surface microhardness of bulk fill, conventional and fiber-reinforced resin based composites (RBCs) through different incremental thicknesses of resin composite. Working hypotheses was that there are differences in transmission of blue light through RBCs of different kinds and that the thickness of the increments influence the degree of monomer conversion of RBCs. Six bulk fill, three conventional nanohybrid, one short fiber reinforced and one flowable RBCs were evaluated. For each material, four different incremental thicknesses (1, 2, 3 and 4mm) were considered (n=5). The specimens were prepared in cylindrical Teflon molds that are open at the top and the bottom sides and cured for 40s by applying the curing unit. After curing process, the specimens were ground with a silicon carbide paper with a grit size of 1200 and 4000, and then stored dry at 37°C for 24h. Light transmission, degree of monomer conversion, surface microhardness were measured and data were analyzed using ANOVA (p=0.05). There were differences in light transmission of resin composites of various types and brands. Low-viscous bulk fill and short fiber-reinforced RBCs presented higher light transmission compared to resin composites of higher viscosity. Reduced light transmission and lower surface microhardness and DC% at bottom side of the specimen suggests that more attention needs to be paid to ensure proper curing of the resin composite in deep cavities.

Light-emitting Diode Light Transmission through Leaf Tissue of Seven Different Crops

Significant advances in controlled-environment (CE) plant production lighting have been made in recent years, driven by rapid improvements in light-emitting diode (LED) technologies. Aside from energy efficiency gains, LEDs offer the ability to customize the spectrum delivered to a crop, which may have untold benefits for growers and researchers alike. Understanding how these specific wavebands are attenuated by plant tissue is important if lighting engineers are to fully optimize systems for CE plant production. In this study, seven different greenhouse and field crops (radish, Raphanus sativus ‘Cherry Bomb II’; red romaine lettuce, Lactuca sativa ‘Outredgeous’, green leaf lettuce, Lactuca sativa ‘Waldmann’s Green’; pepper, Capsicum annuum ‘Fruit Basket’; soybean, Glycine max ’Hoyt’; cucumber, Cucumis sativus ‘Spacemaster’; canola, Brassica napus ‘Westar’) were grown in CE chambers under two different light intensities (225 and 420 μmol·m−2·s−1). Intact, fully expanded upper canopy leaves were used to determine the level of light transmission, at two to three different plant ages, across seven different wavebands with peaks at 400, 450, 530, 595, 630, 655, and 735 nm. The photosynthetic photon flux (PPF) environment that plants were grown in affected light transmission across the different LED wavelengths in a crop-dependent manner. Plant age had no effect on light transmission at the time intervals examined. Specific waveband transmission from the seven LED sources varied similarly across plant types with low transmission of blue and red wavelengths, intermediate transmission of green and amber wavelengths, and the highest transmission at the far-red wavelengths. Higher native PPF increased anthocyanin levels in red romaine lettuce compared with the lower native PPF treatment. Understanding the differences in light transmission will inform the development of novel, energy-saving lighting architectures for CE plant growth.

The effect of intercalants on the host liposome

When phospholipids are vigorously dispersed in water, liposomes are formed. In the present study, we have explored the effect of intercalant concentration on various properties of unilamellar liposomes. Liposomes were sonically intercalated with vitamin E acetate (VitEAc) and hypericin (Hy) until no difference in light transmission was observed, which reflects the formation of liposomes of minimal diameter. Our studies indicate that the intercalant structure and concentration have an influence on the liposome diameter, which could be directly measured by cryogenic transmittance electronic microscopy. Thus, intercalated VitEAc substantially decreased the diameter of unilamellar dimyristoylphosphatidylcholine liposomes, whereas Hy did not. In addition, we followed peak intensities in the absorbance and fluorescence spectra of Hy as a function of intercalant concentration in the liposomal solution. Initially, the fluorescence intensity increased linearly with concentration; however, the curve then arched asymptotically, followed by a decrease in fluorescence at yet higher concentrations. Because the Hy monomer is the only species that emits fluorescence, we believe that the decrease of fluorescence intensity is the result of Hy aggregation.

Effects of Exposure to Physical Factors on Homeopathic Preparations as Determined by Ultraviolet Light Spectroscopy

Clinical trials have reported statistically significant and clinically relevant effects of homeopathic preparations. We applied ultraviolet (UV) spectroscopy to investigate the physical properties of homeopathic preparations and to contribute to an understanding of the not-yet-identified mode of action. In previous investigations, homeopathic preparations had significantly lower UV light transmissions than controls. The aim of this study was to explore the possible effects of external factors (UV light and temperature) on the homeopathic preparations. Homeopathic centesimal (c) dilutions, 1c to 30c, of copper sulfate (CuSO4), decimal dilutions of sulfur (S8), 1x to 30x, and controls (succussed potentization medium) were prepared, randomized, and blinded. UV transmission was measured at six different time points after preparation (from 4 to 256 days). In addition, one series of samples was exposed to UV light of a sterilization lamp for 12 h, one was incubated at 37°C for 24 h, and one was heated to 90°C for 15 min. UV light transmission values from 190 or 220 nm to 340 nm were measured several times and averaged. After each exposure, UV transmission of the homeopathic preparations of CuSO4 was significantly reduced compared to the controls, particularly after heating to 37°C. Overall, the nonexposed CuSO4 preparations did not show significantly lower UV transmission compared to controls; however, the pooled subgroup of measurements at days 26, 33, and 110 yielded significant differences. UV light transmission for S8 preparations did not show any differences compared to controls. Our conclusion is that exposure to external factors, incubation at 37°C in particular, increases the difference in light transmission of homeopathic CuSO4 preparations compared to controls.

Reply to “Comment on ‘Enhanced transmission of light through a gold film due to excitation of standing surface-plasmon Bloch waves’ ”

We reaffirm our belief that there could be no purely local mechanism involving evanescent waves of any kind, which would explain the observed difference in light transmission through two plasmon resonators having exactly the same local geometry but different lengths.

Radiative properties of a turbid medium underlying-surface system

Calculations of the spectral cloud reflectance over bare soil and vegetation are performed in the framework of the asymptotic radiative transfer theory. A simple equation for the threshold value (THV) of the albedo of the underlying surface is derived. The cases of underlying surfaces with the albedos smaller than the THV can be treated as if the albedo of the surface is equal to zero in satellite cloud remote sensing problems.. It was found that the THV increases with the cloud optical thickness. Also, the differences in light transmission by clouds over bare soil and vegetation are studied.

Photoinitiation chemistry affects light transmission and degree of conversion of curing experimental dental resin composites

Introduction The effect of photoinitiator and co-initiator chemistry on the setting reaction and degree of conversion of dental resin-based composites (RBCs) has rarely been determined explicitly. This work examines the effect of type and concentration of photoinitiator and co-initiator on the rate of change of light transmission throughout polymerisation and degree of conversion of model RBC formulations. Methods Bisphenol-A diglycidyl ether dimethacrylate (bis-GMA) and triethylene glycol dimethacrylate (TEGDMA) (6:4 molar ratio) resins filled with silanized glass filler (74 wt.%) and containing various photoinitiators (camphorquinone; CQ, 1-phenyl-1,2-propanedione; PPD, benzil; BZ), co-initiator types ( N, N-dimethyl- p-amino benzoic acid ethyl ester; DABE, N, N-cyanoethyl methylaniline; CEMA, N, N-diethanol- p-toluidine; DEPT) and concentration (0.0–0.3% DABE) were polymerised using a halogen or LED light curing-unit (LCU) for 10, 20 and 40 s. The setting reaction was monitored in real-time by measuring the light transmittance through the curing specimen and bulk degree of conversion (DC) evaluated using Fourier transform infra-red spectroscopy. Results Specimens containing CQ and PPD cured with the halogen LCU did not have a significant effect on DC or changes in light transmission, although a significant increase in DC was observed for CQ compared with PPD specimens cured with the LED LCU. DABE and CEMA were more effective co-initiators than DEPT. Although DC was not limited by co-initiator concentration, the absence of a co-initiator resulted in marked differences in light transmission and decreased DC throughout 40 s irradiation with each LCU type. Conclusions The spectral range emitted from different types of LCU and absorption characteristics of the photoinitiator chemistry of light-activated resin-based composites play a critical role in the efficiency of polymerisation.

Seed Lengths Corresponding to the Final Stage in Seed Abortion of Three Grain Legumes

Previous studies demonstrated that there is a final stage and a maximum dry weight for seed abortion in several grain legumes. In this work, the corresponding seed lengths were determined in soybean [Glycine max (L.) Merr.], pea (Pisum sativum L.), and white lupine (Lupinus albus L.). Two genotypes with differing seed size were studied for each species, and the white lupine cultivar Lublanc was placed in two different growing conditions. A photographic technique based on the difference in light transmission between carpels and seeds was used to monitor in a nondestructive manner the lengthening of seeds in their pod. The fate of each seed (aborted vs. nonaborted) was recorded at maturity and time‐courses of seed length were determined from the photos for seeds of the two categories. The lengthening pattern followed by aborted and nonaborted seeds and the maximum lengths attained by each of these categories showed that there was a given length after which seed abortion did not occur. This length was close for the two cultivars of each species. For Lublanc, growing conditions influenced the average size of aborted seeds but did not change the length after which seed abortion did not occur. The respective maximum length of any aborted seed and the length not exceeded by 95% of aborted seeds were 12 and 10 mm for soybean, 8.5 and 6 mm for pea, and 13 and 11.5 mm for white lupine.

In vitro Evaluation of Buffy‐Coat‐Derived Platelet Concentrates Stored in a Synthetic Medium1

Human blood platelets, prepared by the buffy-coat method, were prepared and stored in different synthetic media. In a synthetic medium based on gluconate, acetate and citrate (GAC), the pH was 6.8 on day 6. This medium was chosen for further evaluation. The total platelet count and the leukocyte contamination were significantly lower in the platelet concentrates (PCs) prepared in GAC compared to PCs prepared in plasma. Platelets stored in plasma or in GAC were equally functional when tested for aggregation and adenosine triphosphate (ATP) secretion. Only stimuli that act through the arachidonic-acid pathway induced a lower platelet response in GAC. Platelet morphology was quantified by measuring the difference in light transmission during stirring at different rates in an aggregometer; no significant differences for platelets stored in GAC as compared to plasma were observed. Activation of platelets was measured by binding of monoclonal antibodies (McAb) against the Gp IIb/IIIa complex and against activation-dependent antigens (GMP 140 from the alpha-granules and a 53-kD glycoprotein from the lysosomal granules). There was no difference in binding of these McAb between platelets prepared and stored in plasma or GAC. We conclude that platelets prepared by the buffy-coat method and stored in GAC have the same in vitro qualities as platelets stored in plasma, except for the lower aggregation response by the arachidonic-acid pathway. This is probably due to an acetate-induced decrease in intracellular pH.

Platelet activation during preparation of platelet concentrates: a comparison of the platelet‐rich plasma and the buffy coat methods

The activation of platelets during the preparation of platelet concentrates (PCs) by two methods was compared. To eliminate interdonor differences, 2 units of whole blood were pooled and subsequently divided into two batches. From one batch, the platelets were harvested as pelleted platelets from platelet-rich plasma (PRP) and from the other as nonpelleted platelets from the buffy coat (BC). The activation of platelets in these PCs was studied immediately after preparation and during storage for up to 9 days at 22 degrees C with gentle agitation. The binding of monoclonal antibodies (MoAbs) against the GP IIb/IIIa complex and against activation-dependent antigens (GMP 140 from the alpha granules and a 53-kDa glycoprotein from the lysosomal granules) was measured. Beta-thromboglobulin (beta-TG) release was also determined. Disc-to-sphere transformation was quantitated by measuring on an aggregometer the difference in light transmission during stirring at different rates and also by light microscopy. Immediately after preparation, platelets derived from PRP had a more spheric morphology (p less than 0.01), had a higher beta-TG release (p less than 0.01), bound more MoAbs against GP IIb/IIIa (p less than 0.01), and expressed more GMP 140 and 53-kDa glycoprotein (p less than 0.01) than did BC-derived platelets. However, these differences had disappeared after 2 days of storage. It was concluded that, immediately after preparation, PRP-derived platelets are more activated than BC-derived platelets. This is most likely a result of the pelleting that follows the second high-speed centrifugation of the PRP.

The effect of iron on in vitro decalcification of human tooth enamel.

The effect of iron chloride on an in vitro acid attack of human enamel was studied. Slices of teeth were covered with varnish except for a window left on one of the enamel surfaces for exposure. The iron salt was used as a supplement to acid gel, or as pretreatment of the enamel surfaces before exposure to the pure gel. Differences in light transmission of the experimental and control specimen from the radiographs taken before and after immersion in the decalcifying media were assessed quantitatively. The increase in radio-opacity of the enamel sections incubated in the iron-containing acid media was attributed to a lower degree of enamel decalcification.

CANDLING AND SIGHTING TECHNIQUES USED IN LASER INVESTIGATIONS OF THE EUROPEAN PINE SAWFLY, NEODIPRION SERTIFER (HYMENOPTERA: DIPRIONIDAE)

Laser treatment of larval and pupal stages within cocoons of Neodiprion sertifer (Geoff.) requires an accurate assessment of viability and the antero-posterior alignment of the cocoon content. The use of the candling technique to assess qualitative features of avian eggs depends on the translucency of the egg shell and the differences in light transmission by other elements within it (Romanoff and Romanoff 1949). Transmitted-light methods have been employed for insects within cocoons by Cushman (1913) and Hanna (1935). A type of candling technique different from previous methods and which was developed in the Zoology Department, University of Guelph, enables N. sertifer cocoon content to be ascertained and is herein described.