Light Transmission Measurements Research Articles

An Automated pre-Dilution Setup for Von Willebrand Factor Activity Assays.

Accurate quantification of von Willebrand factor ristocetin cofactor activity (VWF:RCo) is critical for the diagnosis and classification of von Willebrand disease, the most common hereditary and acquired bleeding disorder in humans. Moreover, it is important to accurately assess the function of von Willebrand factor (VWF) concentrates within the pharmaceutical industry to provide consistent and high-quality biopharmaceuticals. Although the performance of VWF:RCo assay has been improved by using coagulation analyzers, which are specialized devices for blood and blood plasma samples, scientists still report a high degree of intra- and inter-assay variation in clinical laboratories. Moreover, high, manual sample dilutions are required for VWF:RCo determination of VWF concentrates within the pharmaceutical industry, which are a major source for assay imprecision. For the first time, we present a precise and accurate method to determine VWF:RCo, where all critical pipetting and mixing steps are automated. A pre-dilution setup was established on CyBio FeliX (Analytik-Jena) liquid handling system, and an adapted VWF:RCo method on BCS-XP analyzer (Siemens) is used. The automated pre-dilution method was executed on three different, most frequently used coagulation analyzers and compared to manual pre-dilutions performed by an experienced operator. Comparative sample testing revealed a similar assay precision (coefficient of variation = 5.9% automated, 3.1% manual pre-dilution) and no significant differences between the automated approach and manual dilutions of an expert in this method. While no outliers were generated with the automated procedure, the manual pre-dilution resulted in an error rate of 8.3%. Overall, this operator-independent protocol enables standardization and offers an efficient way of fully automating VWF activity assays, while maintaining the precision and accuracy of an expert analyst. Key features • Automated pre-dilution setup for von Willebrand factor concentrates of various natures. • Combination of a liquid handling system (CyBio FeliX) with a coagulation analyzer (BCS-XP). • Simplifies method transfer to other laboratories. • Basic training for CyBio FeliX and BCS-XP is required. Graphical overview VWF:RCo assay principle and measurement setup. Platelets (yellow ellipsoids) with negative surface charge (- - -) are treated with formaldehyde, which partly denatures the cell surface and thus stabilizes platelets for use as assay reagents. Stabilized platelets (dark-yellow-framed yellow ellipsoids) are then brought in contact with ristocetin A (chemical structure shown; black dots), which binds to the platelet surface and facilitates binding of VWF (green circles). The graphs show an example of quantitative determination of platelet agglutination by measurement of light transmission, where increasing amounts of VWF increase light transmission over time. The photo in the left-bottom corner shows the CyBio FeliX setup for VWF sample dilution and the photo in the right-bottom corner displays the BCS-XP system, which is used for VWF:RCo measurements.

Crude oil-water separation with the aid of carbon based materials

Carbon-based materials are commonly utilized in water filtration and purification due to their affordability and environmental friendliness. This study investigates the effectiveness of four different carbon-based materials: activated carbon (AC), graphene oxide (GO), reduced graphene oxide (rGO), and polyethylene (PE) in crude oil–water separation. To test the effectiveness of the separation, light transmission measurements were carried out with the aid of Arduino UNO using a red, green, and blue (RGB) light spectral sensor. The results revealed that the emulsions with AC was the most effective material in the separation, followed by rGO, and GO was the least effective. To explain the mechanism behind the separation performance, the carbon materials have been characterized by x-ray photoelectron spectroscopy (XPS) and Fourier Transform Infrared Spectroscopy (FTIR). The effectiveness of AC and rGO in the separation process was directly related to the quantity of surface oxides. The experimental results are perfectly agreed with published Density functional theory (DFT) calculations of HOMO–LUMO gap energies. AC shows the best performance and the smallest gap, which indicates that it requires less energy for electrons transition between the HOMO and LUMO. This phenomenon can be attributed to the affinity towards hydrogen in the hydrocarbon chains in crude oil.

Smart design of highly luminescent octupolar mesogenic tetra styryl-alkynyl bipyrimidine-based chromophores presenting non-linear optical properties

The research investigations reported in this paper focuses on the influence of rational design on the photophysical properties of new all-organic multifunctional chromophores. Nonlinear optical (NLO) behavior, optical properties and mesogenicity of several new π-conjugated octupolar chromophores, presenting alkoxy styryl-alkynyl donor groups carrying aliphatic achiral and chiral chains in the 3,4/3,5/2,4 position, connected to electron-accepting 2,2-bipyrimidine cores are investigated by various techniques (light-transmission measurements, polarized-light optical microscopy, differential scanning calorimetry measurements, two-photon excited fluorescence and Hyper Rayleigh Scattering). The mesogenic properties were investigated depending on the position of the alkoxy chain and the 3,4 derivatives were found to exhibit liquid-crystal properties with the formation columnar phases over large temperature ranges which were confirmed by small-angle X-ray scattering analysis. All the molecules exhibit exceptional high fluorescence quantum yields values around 80 % and excellent nonlinear optical properties.

Surface wettability control of bubble flow guide for a thin aqueous electrolyte layer of solar photoelectrochemical reactors

Abstract Hydrogen is a promising energy carrier as no carbon dioxide is emitted during its use in fuel cells or combustion. Solar photoelectrochemical water splitting is a potential process for producing renewable hydrogen. Herein, energy transport phenomena are addressed for the future design of large-scale reactors. First, we show that the thickness of the aqueous electrolyte layer is an essential factor for utilizing the full spectrum of solar radiation. The transport of solar irradiation through the aqueous electrolyte is theoretically analysed. Next, based on the measurement of light transmission through hydrogen bubbles generated from a hydrogen evolving electrode, the energy loss caused by the bubbles covering a photoelectrode is discussed. The bubble size distributions at practical current densities are also presented. Then, a bubble flow guide for controlling the stream of bubbles in a thin electrolyte layer is proposed. A design strategy and experimental results verifying the performance of the bubble flow guide are presented. We demonstrate that surface wettability and inclination angle are important for designing an effective bubble flow guide. We examine the surface wettability control using hydrophilic coatings in detail. Changes in the water contact angles as well as bubble adhesion forces on the coated surfaces are demonstrated. In addition, the current experimental method can be used to identify essential issues in photoelectrochemical processes. Because bubble trapping and growth in a flow guide are reflected in the electrode potential variation, the discussion of electrode potential variation would be useful for further developing bubble flow guides. Overall, this study demonstrates the potential for developing and designing solar photoelectrochemical reactors.

Microplastic identification in marine environments: A low-cost and effective approach based on transmitted light measurements

Microplastics have become a significant concern for the well-being of marine ecosystems. Small fragments of plastic debris are released into the environment from both the direct disposal of plastic products and the deterioration of larger items. Ingestion of microplastics by marine life can result in detrimental effects, including physical harm and the accumulation of toxic chemicals in their tissues. The aim of this research is to design a compact and cost-effective measurement system for effectively detecting and quantifying microplastics in marine environments. The proposed system uses a 2.4-inch liquid-crystal display (LCD) panel and a digital USB microscope, both of which are connected to a single-board computer, with a dedicated python-based graphical user interface (GUI). Specifically, the light transmitted through plastic and organic samples was measured in order to identify and classify them. Various types of materials, such as polypropylene, polyvinyl chloride, polycarbonate, polyethylene, and organic algae samples, were tested and the metrological performance of the system has been estimated. The transmittance of the samples analyzed was primarily influenced by their opacity and thickness. In general, thicker materials exhibited significantly lower transmittance values. This trend was particularly evident in organic components and opaque plastic samples, where transmittance was significantly low. In addition, the experimental results suggest that the colour of the material also affects transmittance, although as a secondary factor. The employed technique could be used to identify and distinguish samples based on material properties, thereby allowing the proposed system to be a valuable tool for further research on microplastics in marine environments.

Understanding Flexdispersion: Structure-Function Relationship Studies of Organic Amphiphilic Ligands.

Since inorganic nanoparticles have unique properties that differ from those of bulk materials, their material applications have attracted attention in various fields. In order to utilize inorganic nanoparticles for functional materials, they must be dispersed without agglomeration. Therefore, the surfaces of inorganic nanoparticles are typically modified with organic ligands to improve their dispersibility. Nevertheless, the relationship between the tail group structure in organic ligands and the dispersibility of inorganic nanoparticles in organic solvents remains poorly understood. We previously developed amphiphilic ligands that consist of ethylene glycol chains and alkyl chains to disperse inorganic nanoparticles in a variety of organic solvents. However, the structural requirements for amphiphilic ligands to "flexibly" disperse nanoparticles in less polar to polar solvents are still unclear. Here, we designed and synthesized several phosphonic acid ligands for structure-function relationship studies of flexdispersion. Dynamic light scattering analysis and visible light transmittance measurements revealed that the ratio of alkyl/ethylene glycol chains in organic ligands alone does not determine the dispersibility of the nanoparticles in organic solvents, but the arrangement of the individual chains also has an effect. From a practical application standpoint, it is preferable to design ligands with ethylene glycol chains on the outside relative to the particle surface.

Low-temperature preparation of nanostructured porous sol-gel anti-reflective coating for near-infrared wavelengths

Anti-reflective coatings are crucial in minimizing reflection between different optical media at the interfaces. This study aims to develop an anti-reflective layer for the near-infrared region using a sol-gel coating method combined with a low-temperature plasma-jet-assisted surfactant extraction. For the deposition of the sol-gel layer on glass and polycarbonate substrates, dip-coating and spray-coating techniques were used. Surfactant removal was carried out using a plasma-jet and solvent exchange. Some of the samples were also annealed at 450 °C. The samples were characterized through light transmission measurements, haze percentage determination, 3D laser scanning microscopy, scanning electron microscopy, profilometry, Fourier transform Infrared spectroscopy, ellipsometry and atomic force microscopy. The results showed that the anti-reflective coating layer treated with a plasma-jet and solvent exchange at room temperature demonstrated broadband anti-reflective properties with high transmission in near-infrared regions (up to 7.6% relative improvements in transmission for two sides). Annealing, performed only on the glass substrate, also showed the maximum relative improvement in transmission up to 8% for two sides. Moreover, in the case of polymer-based substrates, a low-temperature process is essential, which is implemented successfully by a plasma-jet method. These findings highlight the effectiveness of the proposed method for fabricating anti-reflective layers on both glass and polycarbonate substrates, offering potential applications in various industries, e.g. where either low-temperature fabrication or cost-cutting, quick and “simple” production methods play a major role for the feasibility of products as in mass markets.

Light transmittance measurement method of solid rocket motor plume based on laser modulation spectrum analysis

AbstractThe light transmittance measurement method, which is used to characterize smoke characteristic signal of solid rocket motor plume, can provide important reference for development and design of low smoke characteristic signal solid propellants and motors. The light transmittance measurement method of solid rocket motor plume based on laser modulation spectrum analysis is proposed in this paper. By using a 405 nm laser as the light source and a narrow‐band filter detection method, the influence of plume radiation on the measurement of light transmittance of solid rocket motor plume smoke can be minimized. Additionally, combined with the laser modulation spectrum analysis technology, the signal amplitude is selected by the laser modulation frequency to improve the signal‐to‐noise ratio of the signal. Compared with the laser constant current measuring mode, laser high‐frequency modulation measuring mode with spectrum analysis effectively improves the optical transmittance measurement accuracy. Based on this, a solid rocket motor plume smoke transmittance test system is developed to measure the plume smoke of standard test motors with different propellants and combustion chamber pressures. The results demonstrate that the system can effectively measure the light transmittance of the plume smoke. The light transmittance of solid rocket motor plume can be increased by reducing the aluminum content of solid propellant or increasing the pressure of the combustion chamber. Thus, this research provides an effective measuring tool for evaluating smoke concentration of solid rocket motor plume, which is beneficial to develop low smoke characteristic signal solid propellants and motors.

Plastic Fiber Low Light Measurement Method

Paper describe researches performed to develop a method for checking the light transmission through plastic scintillating fiber. Such fibers are used in different industrial or research application but for our purpose are main components of a flexible detector. Such detector use photon scintillating signals read by higly sensitive detectors and special measures taken to get such sensitivity. We present in paper a method and algorithm developed for measurement of light transmission through plastic fiber when signals are at level of nW. We develop a stand to implement and verify this method. We use fibers with connectors at each fiber end. Fibers are previously polished at each end in order to allows to pass the signal through surface with low losses. Using the stand we perform measurements to analyse the feasibility of method. We present the results that demonstrate the feasibility of method. We succeed to measure signals at level of nW using special measures. Our results shows that method and stand can be used to measure low level signals through fibers. Using this method, it is possible to check the quality of plastic fiber polishing. A fiber with end surface well-polished allows to pass the signal at such low level (nW).

Study on the Memory Effect in Aerosil-Filled Nematic Liquid Crystal Doped with Magnetic Nanoparticles

A study on 5CB liquid crystal composites with SiO2 nanoparticles and an additional commixture with Fe3O4 nanoparticles using light transmission and SAW measurements is presented. The prepared liquid crystal composites exhibited an interesting memory effect characterized by the hysteresis of both light transmission and SAW attenuation responses investigated in the nematic phase. While in the case of SiO2 nanoparticles as dopants, the liquid crystal composite showed an improvement in the memory effect, the addition of Fe3O4 magnetic nanoparticles resulted in the memory effect decreasing. Additional studies showed a significant shift in both the threshold voltage and nematic–isotropic transition temperature. Measurements in the magnetic field confirmed the increasing memory effect according to that of pure 5CB. The properties of these composites could lead to a potential application for the fabrication of memory devices suitable for information storage.

Assessing soil aggregate stability by measuring light transmission decrease during aggregate disintegration

Assessing soil aggregate stability by measuring light transmission decrease during aggregate disintegration

Light transmittance in human atrial tissue and transthoracic illumination in rats support translatability of optogenetic cardioversion of AF

Abstract Background Optogenetics could offer a solution to the current lack of an ambulatory method for rapid automated cardioversion of AF, but key translational aspects remain to be studied. Objective To investigate whether optogenetic cardioversion of AF is effective in the aged heart and whether sufficient light penetrates the human atrial wall. Methods Atria of adult (7 weeks old) and aged (2 years old) rats were optogenetically modified to express light-gated ion channels (i.e. ReaChR), followed by AF induction and atrial illumination to determine effectivity of optogenetic cardioversion. The irradiance level was determined by light transmittance measurements on human atrial tissue. Results AF could be effectively terminated in remodelled atria of aged rats (97%, n=6). Next, in terms of ReaChR activation, it was shown that light pulses of 25mW/mm2 are expected to fully penetrate the human atrial wall (∼2 mm). Applying such irradiation onto the chest of adult rats resulted in full transthoracic illumination (also ∼2 mm) as evidenced by optogenetic cardioversion of AF (90%, n=4). Conclusion Optogenetic cardioversion of AF is effective in the aged rat heart and can also be realized with irradiation levels compatible with human atrial transmural light penetration.

Investigation of IR Reflective Coating for Plexiglas Canopy

Purpose: Solar energy is necessary for our global ecosystem. In certain times and parts of the world, the heat generated from the energy of the Sun becomes uncomfortable for us and we need to use additional energy to cool down the generated heat from the Sun. This additional energy usage is detrimental to our environment due to generation of air pollution and use of our natural energy resources. The purpose of this paper is to investigate prevention of undesired generation of heat by the Sun using reflective coating materials.
 Methodology: In this study, using literature review, Ga doped Zinc Oxide (GZO) is theoretically investigated as a visible light transparent and infrared reflective coating material for the Plexiglas canopy of a solar car. The effect of doping concentration and film thickness is reviewed and discussed. Indium Tin Oxide (ITO) is also studied, using various literature reviews, as an infrared reflective coating material that is transparent in the visible light region. Finally, a spectrophotometer was used to examine the optical properties of a Plexiglas, slide glass, and ITO coated glass, and the results of UV and visible light transmittance measurement of the three materials is presented and discussed.
 Findings: GZO and ITO films both have high transparency in the visible region of the solar spectrum and high reflectivity to IR radiation starting from 1500 nm to higher wavelengths. None of these films completely reflect the IR radiation with wavelengths in the range of 700 nm to 1500 nm which contribute to generation of heat most. Many factors such as doping concentration and thickness of the films affect reflectivity of the films due to their effect on shifting the plasma frequency. Increasing doping concentration and thickness of the GZO films until a certain threshold improves IR reflectivity of GZO films, but it was not possible to precisely formulate these factors within this study. Reducing the particle size in nanoparticle ITO film improves transmittance of the film in the visible light region and its reflectance in the IR region. The measurement results showed that Plexiglas and glass have a high transparency to visible and near IR radiation.
 Recommendations: Further investigation and experimentation is recommended to fully understand and formulate doping concentration and film thickness of GZO and ITO to achieve optimal IR reflectivity within the 700 to 1500 nm wavelength region while maintaining visible light transparency. In regards to ITO coating, reduced nanoparticle size is recommended to improve the desired visible and IR transparency and reflectivity of the film. Although GZO and ITO coatings’ doping concentration and thickness to achieve IR reflectivity within the 700 to 1500 nm wavelengths is not well understood in this study, to reduce heat generation they are still recommended as a coating material due to their reflectivity to IR with wavelengths of above 1500 nm which also play a role in generation of heat.

Light transmittance in human atrial tissue and transthoracic illumination in rats support translatability of optogenetic cardioversion of atrial fibrillation.

Optogenetics could offer a solution to the current lack of an ambulatory method for the rapid automated cardioversion of atrial fibrillation (AF), but key translational aspects remain to be studied. To investigate whether optogenetic cardioversion of AF is effective in the aged heart and whether sufficient light penetrates the human atrial wall. Atria of adult and aged rats were optogenetically modified to express light-gated ion channels (i.e., red-activatable channelrhodopsin), followed by AF induction and atrial illumination to determine the effectivity of optogenetic cardioversion. The irradiance level was determined by light transmittance measurements on human atrial tissue. AF could be effectively terminated in the remodeled atria of aged rats (97%, n=6). Subsequently, ex vivo experiments using human atrial auricles demonstrated that 565-nm light pulses at an intensity of 25mW/mm2 achieved the complete penetration of the atrial wall. Applying such irradiation onto the chest of adult rats resulted in transthoracic atrial illumination as evidenced by the optogenetic cardioversion of AF (90%, n=4). Transthoracic optogenetic cardioversion of AF is effective in the aged rat heart using irradiation levels compatible with human atrial transmural light penetration.

The Effects of Citric Acid as Crosslinking Agent on Selected Properties of Cassava Starch Films

Materials made from renewable resources offer a promising strategy for reducing environmental problems. Starch is a well-known alternative among several biodegradable materials due to its availability, cheap cost, and degradability. This research aims to develop a degradable film from cassava starch and use citric acid as the crosslinker. Light transmittance measurement reveals that the films produced have high UV barrier capacity in the UV region and above 80% transmittance values in the visible region. Additionally, it was found that the film with 10% citric acid had a favorable balance of tensile strength, elongation, and fracture stress.

Wafer-scale hysteresis-free plasmonic hydrogen sensors based on Pd–Au alloy nanoarrays

The prospective market of hydrogen energy has dramatically boosted the demand for accurate and stable detection of ambient hydrogen. In this work, we fabricated wafer-scale plasmonic hydrogen sensors consisting of periodically distributed Pd–Au alloy nanodiscs by holographic lithography and other semiconductor-compatible techniques, thus obtaining reliable and low-cost sensing devices. Light transmittance measurements at specific light wavelength close to the plasmonic absorption peak position are conducted to investigate the hydrogen sensing performance on account that optical signals afford spark-free operation and high tolerance. Upon alloying Pd with appropriate content of Au, the hysteresis between hydrogen absorption and desorption curves is completely suppressed which greatly improves the sensing accuracy throughout the hydrogen pressure range of 102–105 Pa. Moreover, the precisely defined Pd–Au alloy nanodiscs provide satisfactory stability and device-to-device reproducibility. This work demonstrates an attractive route into practical applications of hydrogen detection for the facile fabrication method and satisfactory performance.

Study of the V[formula omitted] state in neutron-irradiated silicon using photon-absorption measurements

Pieces of n-type silicon with 3.5kΩ cm resistivity have been irradiated by reactor neutrons to 1MeV neutron equivalent fluences of (1, 5 and 10)×1016cm−2. Using light-transmission measurements, the absorption coefficients have been determined for photon energies, Eγ, between 0.62 and 1.30eV for the samples as irradiated and after 15min isochronal annealing with temperatures between 80°C and 330°C. The radiation-induced absorption coefficient, αirr, has been obtained by subtracting the absorption coefficient for non-irradiated silicon. The Eγ-dependence of αirr shows a resonance peak, which is ascribed to the neutral divacancy, V20, sitting on a background, and αirr(Eγ) is fitted by a Breit–Wigner line shape on a parameterized background. It is found that at an annealing temperature of 210∘C the V20 intensity is reduced by a factor 2, and that at the meV level, the position and the width of the fitted Breit–Wigner do not change with irradiation dose and annealing.

Optical and flexoelectric biosensing based on a hybrid-aligned liquid crystal of anomalously small bend elastic constant

Liquid crystal (LC)-based biosensors rely on the response of the LC molecules to perturbation generated by analytes at the interface, leading to the susceptible change in molecular alignment or orientation. The sensitivity of these biosensors is primarily dependent on the LC's material properties and surface anchoring strength. By incorporation of an unconventional mesogenic compound (CB7CB) coupled with the hybrid-alignment cell configuration, this work presents a binary nematic LC for label-free biosensing, manifesting a novel sensing technology that takes advantage of CB7CB-induced flexoelectricity in the transducer. Herein, we prepared LC mixtures by blending a typical rod-like nematic LC (E7) with the bent-core mesogen CB7CB in various weight ratios and studied the effect of the CB7CB content on E7/CB7CB-based biosensing performance in vertically aligned and hybrid-aligned nematic (HAN) cells. Owing to the anomalously small bend elastic constant K33 in CB7CB, the mixture designated CB45 with the highest CB7CB weight percentage (45 wt% in this study) was best applicable to biosensing in HAN cells. When observed under a polarizing optical microscope, CB45 in the HAN geometry showed the capability of detection of as low as 10−10 g/mL for the protein standard bovine serum albumin (BSA). Moreover, the quantitation of the assay was fulfilled by both dielectric and light transmission measurements of the hybrid-aligned cholesteric CB45/R5011. The limit of detection of 7 × 10−10 g/mL was achieved by spectrometric analysis. To the best of our knowledge, this work is the first to demonstrate flexoelectric biosensing on the basis of flexoelectric polarization associated with giant flexoelectricity in CB7CB partially constituting the LC transducer.

PbWO4 Acoustic Properties Measurement by Laser Ultrasonics with the Aim of Optical Damage Recovery

The paper, at first, discusses theoretical aspects of acoustic wave propagation in lead tungstate (PWO). After that, it introduces the application of laser ultrasonics to PWO crystals with the aim of measuring the acoustic properties and the absorbed energy. A specific set-up has been developed to deposit energy in the crystals by means of shock waves generated by a pulsed Nd-YAG laser. We measured the acoustic properties of the PWO crystals along the crystallographic c^ axis and measured the acoustic energy absorption. Calculations confirmed that the majority of the energy has been absorbed in the samples. Since in scintillating crystals the radiation damage leads to a decrease in the optical transmission, the paper formulates the hypothesis that the laser energy absorbed can sustain recovery of the optical transmittance properties. Preliminary tests of light transmittance measurements showed a systematic improvement of optical transmittance after laser treatment in a series of PWO samples. These results are consistent and in agreement with the hypothesis, and they support the feasibility of a laser-based method to recover radiation-damaged crystals.

In situ measurement of light transmission into wine bottles and calculation of shelf life

Wine exposed to UV-A and violet light (320–440 nm) can develop a light-struck flavour which deteriorates its quality. In a short introduction, we briefly describe the two most important photochemical pathways of this process and discuss conditions that facilitate the formation of undesired compounds. The main thrust of the study is to use a novel method to determine light transmission into real wine bottles, along with optical and photochemical modelling of wine damage. Calculation of light transmission into bottles and resulting photochemical damage is described in detail and compared to in situ measurements of transmitted light inside bottles. The effect of different light sources (sunlight, fluorescent bulbs and LED bulbs) is also discussed. It is found in in situ measurements that clear (flint) bottles transmit up to 35 % and bluish-green bottles up to 8 % of the harmful UV–violet light, while light amber bottles only up to 1.2 % and dark amber ones up to 0.2 %. Results of simple tasting experiments support the validity of shelf life calculations described here. According to these findings, white wine in flint (clear) and bluish-green bottles can survive only for a few days while displayed on shelves; light amber bottles conserve the quality for about a month and dark amber bottles for more than a year. Recommendations concerning the protection of shelf-displayed bottled wine from light exposure are also given.