Backscattered Light Intensity Research Articles

β-cyclodextrin modified GO ultrafiltration membranes with enhanced antifouling property for water purification

The study investigated the influence of additives on the fabrication of mixed matrix membranes comprising polyethersulfone (PES), with a specific focus on hydrophilicity, flux, morphology, and antifouling properties. Carboxymethyl modified β-cyclodextrin (CMβ-CD) was used to enhance the dispersion and hydrophilicity of graphene oxide (GO), leading to the formation of a hydrophilic and stable composite nanoparticle (CMCD@GO). The hydrophilicity (WCA <51.5°) and water flux (32.6 L m−2.h−1) of the modified PES membranes (MCDGO-x) were improved by the incorporation of CMCD@GO nanoparticles, while that of PES membrane was 79.7° and 10.6 L m−2.h−1. The rate of backscattered light intensity (ΔBS) of MCDGO-x suspensions remains stable, suggesting stable dispersion of CMCD@GO in organic solvents. Compared to the bare PES membrane, the MCDGO-x membrane exhibits a thinner active layer and a finger-like structure. The MCDGO-x membrane exhibited excellent naphthenic acids (NAs) rejection (>93.2%) due to reduced roughness and higher hydrophilicity, while the GO-modified PES membrane (MGO-5) exhibited lower NAs rejection (87.2%). Furthermore, the MCDGO-5 membrane showed higher flux recovery ratio (FRR) of 79.3% compared to MGO-5 membrane (68.5%) after three cycles, indicating the antifouling performance of MCDGO-x for NAs was significantly improved. The combination of CMβ-CD and GO enhance the flux and antifouling properties of PES ultrafiltration membranes, suggesting significant potential for applications in the purification of oil sands process water and the treatment of oily wastewater.

Influence of hydrocolloids and natural emulsifier in the physical stability of UHT oat beverage.

This study aimed to improve the physical stability of ultra-high temperature (UHT) oat beverage by adding hydrophilic colloids (guar gum [GG] and xanthan gum [XG]) and a natural emulsifier (soluble soybean polysaccharide [SSPS]). The stability of the oat beverage was characterized by particle size, zeta potential, rheological properties, Fourier-transform infrared (FTIR) spectroscopy, backscattered light intensity (ΔBS), and microstructure. The results indicated that XG reduced the average particle size and size distribution of the beverage, indicating that XG could prevent particle aggregation. GG increases the apparent viscosity of the oat beverage without affecting the zeta potential. When SSPS was added to the oat beverage, it increased the absolute value of the zeta potential and the infrared absorption peak intensity, while the average particle size and backscattered light intensity (ΔBS) decreased, resulting in a more uniform microstructure. The zeta potential reached a maximum value of 32.12 when GG, XG, and SSPS were combined, indicating that the physical stability of the oat beverage was effectively improved when all three were present simultaneously. This study may provide some suggestions for the industrial production of low-viscosity cereal beverages with good stability.

Quantitative Tissue Elasticity Measurement of Human Cadaver Oesophagus by Using Vibrational Optical Coherence Elastography

The mechanical properties and structure alteration (e.g., layer morphology and thickness) of the oesophagus wall can reflect its pathological conditions. Hence, quantitative measurement of the above-mentioned properties can play a significant role in aiding the disease diagnosis in clinical application. As a fast and non-invasive imaging modality, Optical coherence tomography (OCT) and vibrational elastography can provide high resolution (&lt;10 µm) structural and mechanical mapping of soft tissue. This study is a preliminary study to explore the potential of OCT and VOCE to evaluate both structural and mechanical properties of the oesophagus wall. Jn total, 52 oesophageal tissue samples were acquired from seven human Thiel-embalmed cadavers and were examined by the vibrational OCE. Both the OCT structure image and quantitative elasticity of each sample layer were obtained. In the OCT structure image, the averaged thickness for each sample layer was measured and corresponded with the histological image. Lamina propria has the largest thickness of 158.14 ± 8.75 µm, submucosa is the thinnest with a thickness of 143.19 ± 10.11 µm, and the thickness of muscularis mucosa is 149.49 ± 10.85 µm. Averaged intensity of back-scattered light from each sample layer was evaluated. Intensity of lamina propria layer, muscularis mucosa layer, and submucosa layer have an average value of 79.27 ± 0.51 dB, 69.83 ± 0.56 dB, and 76.10 ± 0.55 dB, respectively. The quantitative elasticity of each sample layer was evaluated in OCE. Elasticity of the lamina propria layer, muscularis mucosa layer, and submucosa layer were estimated as 115.64 ± 8.80 kPa, 60.28 ± 5.27 kPa, and 205.25 ± 19.03 kPa, respectively. The quantitative elasticity results obtained by vibrational OCE corresponded with the collagen distribution trend in each sample layer. This study demonstrates the ability of OCT and vibrational OCE in the characterisation and quantitative evaluation of human cadaver oesophagus wall-structure properties and mechanical properties. The feasibility of applying OCT and vibrational OCE in clinical diagnosis of oesophageal disease is also discussed.

Optical signal intensity incorporated rice seed cultivar classification using optical coherence tomography

Here, the optical signal intensity of swept-source optical coherence tomography (SS-OCT) was incorporated to assess the images of different rice seeds for precise cultivar classification. Such classification is essential from various agricultural viewpoints but remains challenging because rice seeds have a similar visual appearance. Thus, studies on rice seed cultivar classification play a key role in achieving a successful rice yield. To investigate the feasibility of the proposed approach, two-dimensional OCT images were acquired from two types of rice seed cultivars (Chucheong and Hopyeong), which were then subjected to an optical signal intensity assessment. Based on the depth-dependent optical scan profile results, the averaged and normalized back-scattered light intensity curves revealed a distinct difference between each cultivar, which aided the precise classification of the cultivars. Therefore, the developed optical signal-sensing approach can be extensively applicable to seed cultivar classification in the agricultural industry.

Synergistic effects of AlOOH and sodium benzenesulfonate on the generation of Pickering emulsions and their application for enhanced oil recovery

The surfactant assisted nanoparticle stabilized emulsions exhibit the wide potential application and attract more and more attention. In the present study, the flake-like hydrophilic AlOOH nanoparticles were employed to stabilize Pickering emulsions with the assist of slightly amphiphilic sodium benzenesulfonate (SBS) molecules. The measurements of FTIR spectra, three-phase contact angle, zeta potential and Z-average diameter adequately testified the successful adsorption of SBS on AlOOH nanoparticles. Both slightly amphiphilic SBS and highly hydrophilic AlOOH nanoparticles could hardly stabilize emulsions, whereas the SBS modified AlOOH nanoparticles exhibited distinguished emulsifying capacity, which was reflected via the Turbiscan Stability Index and the reference values of backscattered light intensity. Batch adsorption experiments were conducted and the adsorption data was better fitted to the Langmuir model, suggesting that SBS could form monolayer adsorption on AlOOH nanoparticles. Confocal laser scanning microscopy and rheological measurements demonstrated that the functionalized AlOOH nanoparticles could spontaneously adsorb at the oil/water interface to form an interfacial film and generate a three-dimensional network structure in the continuous phase to effectively prevent droplet coalescence in normal and harsh conditions. Furthermore, SBS/AlOOH stabilized O/W emulsions presented significant displacement performance (tertiary oil recovery of 18.87%) in core flooding experiments. Microscopic visualization tests showed that the emulsions could block high permeability channels and enlarge the sweep area. This study opens up the possibility of adopting low surface-active molecules and hydrophilic nanoparticles to stabilize Pickering emulsions for enhanced oil recovery (EOR).

On the measurement accuracy of coherent Rayleigh-based distributed sensors

The phase change of back-scattered light due to external perturbations is retrieved in coherent Rayleigh-based distributed sensors by estimating the frequency shift (FS) between the traces of different measurements. The uncertainty associated with the estimator, due to the presence of system noises, can lead to an inaccurate evaluation of the FS. Additionally, in coherent Rayleigh-based sensors, the calculation of the signal-to-noise ratio (SNR) from the jagged back-scattered intensity trace using the statistical estimators can cause an erroneous determination of the absolute value of the SNR. In this work, a method to accurately evaluate the non-uniform SNR caused by the stochastic variation of the back-scattered light intensity along the fibre is presented and validated. Furthermore, an analytical expression to evaluate the uncertainty in the FS estimation using one of the standard estimators, namely cross-correlation, is presented. A direct-detection frequency-scanned phase-sensitive optical time-domain reflectometer (φ-OTDR) is employed for the experimental verification of the expression as a function of two crucial system parameters: the SNR and the spatial resolution. The performance of various distributed sensing system configurations utilising cross-correlation for determining the FS occurring due to the external perturbations can be properly predicted hereafter with the aid of the analytical expression presented in this study.

Optical coherence tomography

During the past decade, noninvasive imaging has emerged as a valuable tool in clinical dermatology and dermatologic research. Optical coherence tomography (OCT) is one such type of noninvasive imaging. OCT uses the principle of interferometry to produce real-time images. A low-power diode laser shines infrared light onto tissues, which reflects back to an optical fiber interferometer. Using time delay and the backscattered light intensity, a two-dimensional image akin to an ultrasound is rendered. We review the history, types, and modalities of OCT, plus the many applications of frequency domain, high definition, and dynamic OCT in practice, including its utility in diagnosis, monitoring, and grading disease severity in a variety of cutaneous conditions.

Effect of the oat β-glucan on the development of functional quinoa (Chenopodium quinoa wild) milk

This study aimed to produce novel plant-based milk from quinoa with the addition of oat β-glucan (OGB). The stability of quinoa milk was characterized by zeta potential, particle size, separation index (SI), rheological property, backscattered light intensity (ΔBS), and microstructure. Results showed that OGB addition efficiently prevented the phase separation of quinoa milk, and the highest SI and zeta potential values were obtained at the optimal pH 6.0. Quinoa milk presented a higher apparent viscosity and a narrower particle distribution with the increased OGB concentration, however, it did not affect the zeta potential. Moreover, OGB improved the storage stability with an increased SI and a ΔBS. Microstructure analysis suggested that OGB could prevent phase separation by constructing a network structure, and an increased amount of OGB led to forming a gel-like structure. An excessive viscosity would decrease the sensory acceptance, therefore the final OGB concentration of 16% was selected.

A preliminary study of post-progressive nail-art effects on in vivo nail plate using optical coherence tomography-based intensity profiling assessment

Nail beautification is a widely applied gender independent practice. Excessive nail beautifications and nail-arts have a direct impact on the nail structure and can cause nail disorders. Therefore, the assessment of post-progressive nail-art effects on the nail is essential to maintain optimal nail health and to avoid any undesirable disorders. In this study, in vivo nails were examined in control stage, with a nail-art stage, and after removing the nail-art stage using a 1310 nm spectral-domain optical coherence tomography (SD-OCT) system. The acquired cross-sectional OCT images were analyzed by a laboratory customized signal processing algorithm to obtain scattered intensity profiling assessments that could reveal the effects of nail beautification on the nail plate. The formation and progression of cracks on the nail plate surface were detected as an effect of nail beautification after 72 h of nail-art removal. Changes in backscattered light intensity and nail plate thickness of control and art-removed nails were quantitatively compared. The results revealed the potential feasibility of the developed OCT-based inspection procedure to diagnose post-progressive nail-art effects on in vivo nail plate, which can be helpful to prevent nail plate damages during art removal through real-time monitoring of the boundary between the nail plate and nail-art. Besides nail-art effects, the developed method can also be used for the investigation of nail plate abnormalities by examining the inconsistency of internal and external nail plate structure, which can be diagnosed with both qualitative and quantitative assessments from a clinical perspective.

Improvement in physical and thermal stability of cloudy ginkgo beverage during autoclave sterilization: Effects of microcrystalline cellulose and gellan gum

This work aimed to apply microcrystalline cellulose (MCC) and gellan gum to improve the physical and thermal stability of cloudy ginkgo beverages. The stability of each beverage samples was characterized in terms of particle size, size distribution, zeta potential, rheological properties, Turbiscan Stability Index (TSI), and changes in backscattered light intensity (△BS). Our results indicate that an irreversible phase separation occurred in the beverage sample, induced by increased particle size, decreased zeta potential, and decreased viscosity during the sterilization process. Although the addition of either MCC or gellan improved beverage stability by decreasing particle size and increasing zeta potential, this improvement was limited; the aggregation and sedimentation of suspended particles still occurred, as revealed by large △BS and TSI changes. Beverage samples added with a mixture of MCC and gellan exhibited different physical and thermal stability values depending on the ratio of MCC to gellan. The addition of MCC (0.3%, w/w) combined with a small amount of gellan (0.05% or 0.08%, w/w) effectively prevented drastic thermal damage and improved physical and thermal beverage stability in comparison to MCC combined with the larger amount of gellan. This study provides some suggestions for the industrial production of cloudy beverages.

A wide field-of-view, modular, high-density diffuse optical tomography system for minimally constrained three-dimensional functional neuroimaging.

The ability to produce high-quality images of human brain function in any environment and during unconstrained movement of the subject has long been a goal of neuroimaging research. Diffuse optical tomography, which uses the intensity of back-scattered near-infrared light from multiple source-detector pairs to image changes in haemoglobin concentrations in the brain, is uniquely placed to achieve this goal. Here, we describe a new generation of modular, fibre-less, high-density diffuse optical tomography technology that provides exceptional sensitivity, a large dynamic range, a field-of-view sufficient to cover approximately one-third of the adult scalp, and also incorporates dedicated motion sensing into each module. Using in-vivo measures, we demonstrate a noise-equivalent power of 318 fW, and an effective dynamic range of 142 dB. We describe the application of this system to a novel somatomotor neuroimaging paradigm that involves subjects walking and texting on a smartphone. Our results demonstrate that wearable high-density diffuse optical tomography permits three-dimensional imaging of the human brain function during overt movement of the subject; images of somatomotor cortical activation can be obtained while subjects move in a relatively unconstrained manner, and these images are in good agreement with those obtained while the subjects remain stationary. The scalable nature of the technology we described here paves the way for the routine acquisition of high-quality, three-dimensional, whole-cortex diffuse optical tomography images of cerebral haemodynamics, both inside and outside of the laboratory environment, which has profound implications for neuroscience.

Stability of pH-responsive Pickering emulsion stabilized by carboxymethyl starch/xanthan gum combinations

The objective of this study was to investigate the effect of different pH values (3, 5, 7, 9 and 11) on the stability of Pickering emulsions stabilized by carboxymethyl starch (CMS)/xanthan gum (XG) combinations. The CMS/XG combinations could be used as an effective stabilizer for the preparation of Pickering emulsion. The effects of CMS/XG combinations on oil droplet size, Zeta potential, rheological properties, backscattering profiles, Low-field nuclear magnetic resonance imaging and storage stability of oil-in-water emulsion were evaluated as a function of pH. As pH increased from 3 to 11, the droplet size of the emulsion increased and the absolute value of Zeta potential decreased. Besides, the consistency coefficient of the emulsion was reduced and the pseudoplasticity was weakened. The variation of backscattered light intensity of the emulsion at pH 3 was the smallest. The combination of CMS and XG formed a good network structure and inhibited the phase separation of emulsion. The color distribution of Low-field nuclear magnetic resonance imaging of emulsions at pH 3, 5 and 7 was more uniform and had better storage stability at 25 °C for 9 days. pH affected the aggregation of oil droplets. The Pickering emulsion stabilized by CMS/XG combinations was pH-responsive and could be used as an effective carrier for biologically active substances.

Investigation of optical laser beam impairment on hypergolic lunarlander exhaust plumes for a lidar feasibility study

Plumes of two hypergolic bipropellant thrusters of a LunarLander application, developed by ArianeGroup® Lampoldshausen, were optically examined regarding their potential to interfere with laser beams of a nearby LIDAR system. On one hand, hot exhaust gas of a 22 N Vernier thruster was used to investigate the scattering of a λ = 632.8 nm HeNe laser beam. A series of several engine pulse modes were conducted. An obvious correlation between engine pulse duration and backscattered light intensity is revealed. The shortest pulses result in the most intense backscattering, indicating an incomplete combustion process between the hypergolic constituents MMH = monomethylhydrazine and NTO = (di)nitrogen tetroxide for very short pulse lengths. On the other hand, a prolonged pulse mode of 120 ms firing time causes only marginal deflection of the laser beam. Furthermore, steady operation leads to a negligible signal of backscattered photons, accompanied by increasing emission bands of combustion products such as CN, O2, and CO2. However, the disappearance of the OH* emission band, typical for this hypergolic combustion, shows a nearly complete reaction of the hydroxyl radical within the combustor for all pulse modes. Mie scattering calculations show a correlation between the incident laser beam wavelength and the backscattered light intensity. On the other hand, near infrared spectroscopy on the exhaust plume of a 500 N apogee thruster revealed that interfering flame emission and absorption in the optical range around λ = 1064 nm can be neglected. The relatively intense flame emission measured for λ ≥ 1300 nm, on the other hand, is a potential risk for the application of a laser beam of a similar wavelength.

Comparative studies on the stabilization of Flos Sophorae Immaturus beverages by various hydrocolloids

The effects of microcrystalline cellulose (MCC), gellan gum (GG) and mixed emulsifiers on physical stability of cloudy Flos sophorae immaturus (FSI) beverages were studied. The physical stability of FSI beverages characterized by particle size, microstructure, rheological properties, suspension stability index and backscattered light intensity. It occurred an irreversible phase separation during thermal sterilization process in the original FSI beverage. The beverage adding MCC had large (the volume weighted mean diamete [d43]~36 μm) but non-coalesced particles after thermal sterilization step, showing MCC could protect the particles against the coalescence. Moreover, when MCC and GG were added to FSI beverage, the suspension stability index increased, and the particle size and the change of backscattered light intensity (△BS) decreased. Mixed emulsifiers not only enhance the viscosity of beverage but also influence the properties of beverage interface, leading to greater absolute value of zeta potential which rose to 45.5 mV. In the existence of MCC, GG, and mixed emulsifiers, the system displayed greater stability than others. This study provided some suggestions for the industrial production of cloudy beverages with low viscosity and good stability.

Intensity Measurement of Backscattered Light from Underwater Targets Using Femtosecond Pulse Laser

In this paper, we experimentally perform the measurement of the backscattered light intensity from the underwater targets with different size. We develop a simple system, which can easily measure the intensity of the backscattered light, after the laser is scattered at the target underwater. We find that, the signal period is related to the particle size, and the stability of the intensity (standard deviation) varies linearly with changing the particle size. After the calibration, our system can be used to precisely determine the particle size of arbitrary targets. Our method could open a new opportunity for the future underwater detection using femtosecond pulse laser.

A novel electronic gate that identifies and counts bees based on their RGB backscattered light

In this work, we present an electronic gate that aims to extract a deeper representational signal of the color characterization of the main body of an insect, namely: a) we record the backscattered light and not the extinction light as commonly done, b) a color sensor analyses backscattered light to individual RGB channels independently to grasp the melanization, microstructural and color features of the wing and body of the insects passing the gate. We present all the necessary details to reproduce the device and we analyze many insects of interest like the bee Apis mellifera and the wasp Polistes gallicus. The electronic gate is attached to the entrance of the beehive and counts foraging activity. The backscattered light intensity can quantify the size of the incoming insect and discern a drone and a worker bee from a queen bee while the color measurements aim to recognize invasive species so that the gate closes and the beekeepers are alerted.

混沌脉冲激光雷达水下目标探测

Absorption and scattering of seawater for light waves seriously restrict the performance of laser radar for underwater target detection. Quantitative analysis of laser backscattering generated by seawater shows that the laser echo signal is seriously affected by seawater backscattering. The ability of range-gated technology and intensity modulation technology to suppress backscattering of seawater was analyzed and compared. A chaotic pulse laser with high frequency intensity modulation was proposed for underwater target detection and the scheme was designed. Based on the study of the characteristics of backscattering light and echo signal with different backscattering intensity in time and frequency domain, the ability of chaotic pulse lidar to suppress backscattering from seawater was determined by using cross-correlation noise level algorithm. The theoretical analysis shows that the target signal can still be extracted when the backscattered light intensity is 36 times that of the chaotic pulse laser.

Active Delivery of Single DNA Molecules into a Plasmonic Nanopore for Label-Free Optical Sensing.

Plasmon resonance biosensors provide ultimate sensitivity at the single-molecule level. This sensitivity is, however, associated with a nanometer-sized confined hotspot, and molecular transport toward the sensor relies on inefficient diffusion. Here, we combine a plasmonic nanoantenna with a solid-state nanopore and demonstrate that single DNA molecules can be efficiently delivered to the plasmonic hotspots and detected in a label-free manner at submillisecond acquisition rates by monitoring the backscattered light intensity from the plasmonic nanoantennas. Our method realizes a better than 200 μs temporal resolution together with a down to subsecond waiting time, which is orders of magnitude better than traditional single-molecule plasmonic resonance sensing methods. Furthermore, the electric field applied to the nanopore can actively drive biomolecules away from the hotspot, preventing molecules to permanently bind to the gold sensor surface and allowing efficient reuse of the sensor. Our plasmonic nanopore sensor thus significantly outperforms conventional plasmon resonance sensors and provides great opportunities for high-throughput optical single-molecule-sensing assays.

Non-Destructive Classification of Diversely Stained Capsicum annuum Seed Specimens of Different Cultivars Using Near-Infrared Imaging Based Optical Intensity Detection.

The non-destructive classification of plant materials using optical inspection techniques has been gaining much recent attention in the field of agriculture research. Among them, a near-infrared (NIR) imaging method called optical coherence tomography (OCT) has become a well-known agricultural inspection tool since the last decade. Here we investigated the non-destructive identification capability of OCT to classify diversely stained (with various staining agents) Capsicum annuum seed specimens of different cultivars. A swept source (SS-OCT) system with a spectral band of 1310 nm was used to image unstained control C. annuum seeds along with diversely stained Capsicum seeds, belonging to different cultivar varieties, such as C. annuum cv. PR Ppareum, C. annuum cv. PR Yeol, and C. annuum cv. Asia Jeombo. The obtained cross-sectional images were further analyzed for the changes in the intensity of back-scattered light (resulting due to dye pigment material and internal morphological variations) using a depth scan profiling technique to identify the difference among each seed category. The graphically acquired depth scan profiling results revealed that the control specimens exhibit less back-scattered light intensity in depth scan profiles when compared to the stained seed specimens. Furthermore, a significant back-scattered light intensity difference among each different cultivar group can be identified as well. Thus, the potential capability of OCT based depth scan profiling technique for non-destructive classification of diversely stained C. annum seed specimens of different cultivars can be sufficiently confirmed through the proposed scheme. Hence, when compared to conventional seed sorting techniques, OCT can offer multipurpose advantages by performing sorting of seeds in respective to the dye staining and provides internal structural images non-destructively.

Measurement of Sediment Concentration of the Oscillatory Flow in the Surf- and Swash-zone

Wang, J.; Qu, Z.; Xu, Z.; Shim, J.S.; Liang, B., and Lee, D.Y., 2018. Measurement of Sediment Concentration of the Oscillatory Flow in the Surf- and Swash-zone.. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 1231–1235. Coconut Creek (Florida), ISSN 0749-0208.The sediment transports near the bed need to be accurately observed to validate the existing models that are based on the empirical formula for the sediment flux and to develop more realistic morphology prediction model. One of the essential tasks for the evaluating the existing models and developing new one is the precise measurement of the sediment transport at swash zone without disturbing flow. Different methods in estimating the sediment transport rates at the surf-zone and swash-zone such as measuring the time evolution of the bed profile, sand ripple volume and migration speed are investigated and evaluated. To develop more reliable estimation of the sediment flux by measuring the vertical profiles of sediment concentration and velocity without disturbing the flow conditions, method of estimation of the vertical sediment concentration profile by detecting the backscattered light intensity using high quality camera was tested and evaluated. The problems of different methods in estimating the sediment flux are identified and discussed.