Variation Of Light Intensity Research Articles

Modulation of morpho-physiological attributes and in situ analysis of secondary metabolites using Raman spectroscopy in response to red and blue light exposure in Artemisia annua

Differential light conditions, such as variations in photoperiod, light quality, and light intensity, play a crucial role as external factors that can influence plant morphogenesis and secondary metabolism. However, there is still a lack of understanding of how Artemisia annua responds to monochromatic and dichromatic light regimes in terms of the different physiological mechanisms that control plant growth and secondary metabolite production. Therefore, the primary aim of this study was to investigate and assess the various physiological parameters, biochemical analysis, and molecular aspects in detail. Therefore, the plantlets were exposed to LED lighting such as monochromatic red light (R), monochromatic blue light (B), white light (W), and a combination of red and blue light (RB, 1:1) at a PPFD (photosynthetic photon flux density) of 200 mol. m−2. s−1 for 10 days. Our results indicate that exposure to RB light resulted in an immense increase in ROS accumulation, flavonoids, lignin, and artemisinin by 4.7-fold, 44%, and 53.4%, respectively, in contrast to W light. Whereas blue light led to increments of 160.2% in phenolic and 107.9% in anthocyanin content. RB and B light also influence the parameters of chlorophyll fluorescence, as well as leaf area, stomatal density, trichome size, antioxidant enzyme activity, and the production of more secondary metabolites to combat oxidative stress. Real-time PCR analysis of biosynthetic pathway-associated genes HMGR, DXR, DXS, FPS, ADS, CYP71AVI, DBR2, ALDH1, and flavonoid key biosynthesis pathway genes PAL, C4H, 4CL, CHS, and F3′H showed the highest increment under RB, light followed by B and R light exposure. Further, RB LED light has significant potential for enhancing natural bio-active compounds as revealed by Raman spectroscopy, such as camphor, limonene, terpene-4-ol, α pinene, 1,8-cineole, β-caryophyllene, artemisinin, kaempferol, luteolin, rutin, and caffeic acid in A. annua. Taken together, red and blue LEDs can serve as significant elicitors for the production of commercially important metabolites.

Beam search decoder for enhancing sequence decoding speed in single-molecule peptide sequencing data.

Next-generation single-molecule protein sequencing technologies have the potential to significantly accelerate biomedical research. These technologies offer sensitivity and scalability for proteomic analysis. One auspicious method is fluorosequencing, which involves: cutting naturalized proteins into peptides, attaching fluorophores to specific amino acids, and observing variations in light intensity as one amino acid is removed at a time. The original peptide is classified from the sequence of light-intensity reads, and proteins can subsequently be recognized with this information. The amino acid step removal is achieved by attaching the peptides to a wall on the C-terminal and using a process called Edman Degradation to remove an amino acid from the N-Terminal. Even though a framework (Whatprot) has been proposed for the peptide classification task, processing times remain restrictive due to the massively parallel data acquisicion system. In this paper, we propose a new beam search decoder with a novel state formulation that obtains considerably lower processing times at the expense of only a slight accuracy drop compared to Whatprot. Furthermore, we explore how our novel state formulation may lead to even faster decoders in the future.

High Dynamic Pixel Implementation Method for Adaptive Adjustment of Gate Voltage of Transfer Transistor on Chip

In CMOS Image Sensors (CIS), high dynamics are required to adapt to the variation of light intensity in different application scenarios. In this paper, we propose a highly dynamic method based on an 8T active pixel, which can adjust the gate voltage of the transfer transistor on the chip adaptively by changing the gate voltage of the transfer transistor in the pixel, to adjust the height of the potential barrier between the PD and FD nodes so that the PD node inside the pixel can fuse the signals of long and short exposures. The output of the sampled pixels is compared with the reference voltage, and the result is output to the gate of the transfer transistor through the DAC to determine the total exposure time allocation, achieving the effect of adaptive adjustment of the exposure time allocation by the pixel output. Based on the 55 nm process, the proposed method is verified by a specific circuit design, and the validation results show that the full trap capacity is 24 ke− and the dynamic range can be extended from 66.02 dB to 89.54 dB without decreasing the pixel fill factor and increasing the signal processing complexity, and the long and short exposure times can be adjusted adaptively according to the application scenario to obtain the optimal high dynamic. The solution is optimized for high dynamics.

Quantifying the Effect of Light Intensity Uniformity on the Crop Yield by Pea Microgreens Growth Experiments

Differences in individual plant growth are affected by the spatial variation of light intensity, reducing the homogeneity of microgreen crops. Identifying the tradeoffs between light uniformity and crop quality is challenging due to the confounding effect of nonuniform illuminance with other noise factors. This study presents the results of hydroponic pea (Pisum sativum, L.) growth experiments aimed at quantifying the effect of photon irradiance variations. By adjusting the power of LED luminaires, we established one uniformly illuminated zone and two non-uniformly illuminated zones. Germinated seeds with 6 cm-long radicles were transplanted to cultivation trays with known light intensity in predetermined positions. Plants were cut 12 days after the start of light treatment and measured for fresh weight and shoot height. Our findings revealed no significant difference between the crop yield on trays having the same average PPFD but different light uniformity. However, correlation analysis of individual measurement data showed that local PPFD differences explained 31% of the fresh weight variation, and the rest was attributed to noise in the germination and growth processes. We also discuss the implications of our findings for the design and optimization of vertical farms.

Light efficacy estimation for fruit trees based on LIDAR point clouds: A case study on pear trees

It is important to evaluate the effect of fruit-tree pruning based on canopy-structure characteristics so as to keep appropriate illumination for tree growth. However, current pruning and evaluation mainly rely on manual experience due to lacking a convenient and automatic approach to obtain such features. This paper proposes a method for estimating light efficacy based on layered canopy point-clouds, where leaf-area was selected as the canopy characteristic. LIDAR was utilised to scan pear trees in three dimensions to acquire initial point clouds, and preprocess was conducted to obtain the point-cloud images of different canopy layers. Then, an optimised algorithm based on Freeman Chain was developed to accurately draw the outlines of point-cloud clusters in the images, and pixel proportion was used to calculate the real leaf-area of each layer. Finally, based on Deep Neural Network, an estimation model was established between different layer leaf-areas and their average illumination acquired in tests. The proposed method was applied to estimate the illumination of a random pear tree to evaluate the variation of light intensity. The results showed that: 1) the average relative error of leaf-area calculation of the optimised Freeman Chain method was about 6.74 %, although the running duration was longer than the conventional one, 2) the overall correlation coefficient, R, of the model was more than 0.95, while that of validation and test sets were more than 0.94, and 3) the illumination estimation was accurate and precise with an average relative error of 1.42 % and a standard deviation of relative errors of 1.19. The validation indicated that this method could achieve the prediction of illumination based on different leaf-area characteristics. The study is expected to give a technical solution for the illumination evaluation before and after tree pruning.

Deep Semi-calibrated Near-field Photometric Stereo

Light calibration plays a crucial role in near-field photometric stereo for accurate surface normal estimation. It comprises light position calibration and light intensity calibration. In industrial applications, the light position calibration is typically performed once, as the facility remains fixed. However, the light intensity calibration needs to be repeated for real industrial scenes with variations in light intensity and fails for autoexposure industrial scenes. This study introduces a deep semi-calibrated near-field photometric stereo technique that achieves precise surface normal estimation without light intensity calibration. The technique consists of two parts: the near-field light intensity calibration network (NFLICN) and the near-field normal estimation network (NFNEN). NFLICN utilizes a point light model to self-calibrate pixel-wise light intensity. NFNEN, on the other hand, takes the calibrated light intensity as input and effectively utilizes local image features to estimate the surface normal. Experimental results on both synthetic testing datasets and the benchmark LUCES dataset confirm the state-of-the-art accuracy of our proposed method in surface normal estimation, even without light intensity calibration.

Development of methane leakage telemetry system based on tunable diode laser absorption spectroscopy

A methane telemetry system based on Tunable Diode Laser Absorption Spectroscopy (TDLAS) is proposed for the long-range, high-precision, and real-time measurement of methane concentration in coal mine safety production. The output wavelength of the tunable semiconductor laser is controlled to scan at 1654nm (6045.94cm−1) of the methane absorption spectrum. The harmonic signal is obtained by digital phase locking technique, and the effect of light intensity variation on the system measurement results is eliminated by 2f/1f signal processing technique. Through calibration experiment and measurement error analysis, the measurement error of the system is less than 10%, which proves that the device has the advantages of high accuracy.

Effects of Ultrasonic Stimulation and Light Intensity on the Growth Rate and Biomass Productivity of Chlorella ellipsoidea in a Closed-Batch Cultivation System

Microalgae exhibit high nutritional value as animal feed in aquatic animal nurseries. Therefore, approaches to enhance biomass productivity are of great economic significance. This study aimed to evaluate the effect of ultrasonic wave stimulation on the specific growth rate and biomass yield of Chlorella ellipsoidea strain TISTR 8260. C. ellipsoidea stimulated by ultrasonic waves at 50 Hz for 1, 5, and 10 min were cultivated in a closed-batch cultivation system with varying light intensities. Data revealed that stimulation for 1 min and rearing at 71.43 μmol m−2 s−1 resulted in the highest biomass productivity and specific growth rates, with averages of 0.89±0.008 g/L/day and 0.59±0.009 per day, respectively. The findings of this study emphasize the usefulness of ultrasonic waves in enhancing the biomass productivity of microalgae.

A Sparse Local Binary Pattern extraction algorithm applied to event sensor data for object classification

Recently, new sensors with active pixels were brought to market. These sensors export local variations of light intensity in the form of asynchronous events with low latency. Since the data output format is a stream of addressable events and not a complete image of light intensities, new algorithms are required for known problems in the field of Computer Vision, such as segmentation, VO, SLAM, object, and scene recognition. There are some proposed methodologies for object recognition using conventional methods, convolutional neural networks, and third-generation neural networks based on spikes. However, convolutional neural networks and spike neural networks require specific hardware for processing, hard to miniaturize. Also, several traditional Computer Vision operators and feature descriptors have been neglected in the context of event sensors and could contribute to lighter methodologies in object recognition. This paper proposes an algorithm for local binary pattern extraction in sparse structures, typically found in this context. This paper also proposes two methodologies using local binary patterns to captures with event-based sensors for object recognition. The first methodology exploits the known motion performed by the sensor, while the second is motion agnostic. It is demonstrated experimentally that the LBP operator is a fast and light alternative that enables variable reduction using PCA in some cases. The experiments also show that it is possible to reduce the final feature vector for classification by up to 99,73% when compared to conventional methods considered state-of-the-art while maintaining comparable accuracy.

Effect of Protective Layer on the Performance of Monocrystalline Silicon Cell for Indoor Light Harvesting.

The development of renewable energy sources has grown increasingly as the world shifts toward lowering carbon emissions and supporting sustainability. Solar energy is one of the most promising renewable energy sources, and its harvesting potential has gone beyond typical solar panels to small, portable devices. Also, the trend toward smart buildings is becoming more prevalent at the same time as sensors and small devices are becoming more integrated, and the demand for dependable, sustainable energy sources will increase. Our work aims to tackle the issue of identifying the most suitable protective layer for small optical devices that can efficiently utilize indoor light sources. To conduct our research, we designed and tested a model that allowed us to compare the performance of many small panels made of monocrystalline cells laminated with three different materials: epoxy resin, an ethylene-tetrafluoroethylene copolymer (ETFE), and polyethylene terephthalate (PET), under varying light intensities from LED and CFL sources. The methods employed encompass contact angle measurements of the protective layers, providing insights into their wettability and hydrophobicity, which indicates protective layer performance against humidity. Reflection spectroscopy was used to evaluate the panels' reflectance properties across different wavelengths, which affect the light amount arrived at the solar cell. Furthermore, we characterized the PV panels' electrical behavior by measuring short-circuit current (ISC), open-circuit voltage (VOC), maximum power output (Pmax), fill factor (FF), and load resistance (R). Our findings offer valuable insights into each PV panel's performance and the protective layer material's effect. Panels with ETFE layers exhibited remarkable hydrophobicity with a mean contact angle of 77.7°, indicating resistance against humidity-related effects. Also, panels with ETFE layers consistently outperformed others as they had the highest open circuit voltage (VOC) ranging between 1.63-4.08 V, fill factor (FF) between 35.9-67.3%, and lowest load resistance (R) ranging between 11,268-772 KΩ.cm-2 under diverse light intensities from various light sources, as determined by our results. This makes ETFE panels a promising option for indoor energy harvesting, especially for powering sensors with low power requirements. This information could influence future research in developing energy harvesting solutions, thereby making a valuable contribution to the progress of sustainable energy technology.

Widespread use of proton-pumping rhodopsin in Antarctic phytoplankton

Photosynthetic carbon (C) fixation by phytoplankton in the Southern Ocean (SO) plays a critical role in regulating air-sea exchange of carbon dioxide and thus global climate. In the SO, photosynthesis (PS) is often constrained by low iron, low temperatures, and low but highly variable light intensities. Recently, proton-pumping rhodopsins (PPRs) were identified in marine phytoplankton, providing an alternate iron-free, light-driven source of cellular energy. These proteins pump protons across cellular membranes through light absorption by the chromophore retinal, and the resulting pH energy gradient can then be used for active membrane transport or for synthesis of adenosine triphosphate. Here, we show that PPR is pervasive in Antarctic phytoplankton, especially in iron-limited regions. In a model SO diatom, we found that it was localized to the vacuolar membrane, making the vacuole a putative alternative phototrophic organelle for light-driven production of cellular energy. Unlike photosynthetic C fixation, which decreases substantially at colder temperatures, the proton transport activity of PPR was unaffected by decreasing temperature. Cellular PPR levels in cultured SO diatoms increased with decreasing iron concentrations and energy production from PPR photochemistry could substantially augment that of PS, especially under high light intensities, where PS is often photoinhibited. PPR gene expression and high retinal concentrations in phytoplankton in SO waters support its widespread use in polar environments. PPRs are an important adaptation of SO phytoplankton to growth and survival in their cold, iron-limited, and variable light environment.

Development of a sodium acetate trihydrate-based phase change material for efficient solar/electric-to-thermal energy conversion

The need to heat buildings during peak periods increases energy consumption. Solar/electric-to-thermal energy conversion heat storage systems can effectively address the heating mismatch issue due to variable solar light intensity. Sodium acetate trihydrate (SAT), borax, and sodium carboxymethyl cellulose (CMC) were used as the solar/electric energy storage medium, nucleating agent, and thickening agent, respectively. A carbon material, expanded graphite (EG), was used as the thermal conductor and solar/electric energy conversion enhancer. EG also acts as a nucleating agent synergistically with borax. The results show that adding 4 wt% EG, 1 wt% borax, and 2 wt% CMC decreased the supercooling of SAT to 1 °C without phase separation, and the composite exhibited excellent thermal cycling stability and a high latent heat storage capacity of 261.5 J/g. The thermal conductivity of the composite increased by 287.7% compared to pure SAT, and its solar-to-thermal energy conversion and electric-to-thermal energy conversion efficiencies reached 90.3% and 87.1%, respectively. This study offers a method for developing thermal storage systems with multiple energy conversion capabilities for prospective applications in solar energy utilization, electrical energy recovery, and building heating.

Portable Particle Sizing Concept for Beach Sand Identification for Forensic Purposes:A Success Case Application of DLS/PCS

Abstract A cheap and simple experimental setup for executing particle sizing in water disperion by means of dynamic light scattering (DLS) and consequently the necessary software to evaluate the calculations of photon correlation spectroscopy (PCS) are described here in order to characterize beach sand by its source location according to the mean beach sand grain hydrodynamic diameter. Despite the existence of similar commercial particle sizing equipments, the innovation presented here consists of a portable measurements able to be used in the field. It consists of an easy handling apparatus composed by a solid-state laser pointer as light source and a smartphone CCD camera as detector for video acquiring. Correlation calculus of light intensity variations were performed in a software developed by the authors. The performance test of the proposed protocol was evaluated to characterize beach sand particles on aqueous solution determining its hydrodynamic diameter. The limitations of the technique were explored and comparison with optical microscopy results and literature were performed.

InP Quantum Dots Tailored Oxide Thin Film Phototransistor for Bioinspired Visual Adaptation

AbstractThe exploration of bionic neuromorphic chips, capable of processing sensory data in a human‐like manner, is both a trend and a challenge. There is a strong demand for phototransistors that offer broadband in‐sensor adaptability. This study introduces a bioinspired vision sensor based on InP quantum dots (QDs)/InSnZnO hybrid phototransistors. This novel design combines the excellent electrical transportation features of oxide semiconductors with the superior optoelectronic response of InP QDs. The resulting hybrid devices exhibit exceptional gate controllability and a robust visible‐light response. These characteristics enable the emulation of multiple functions of the human visual system and the accommodation of varying light intensity environments. Furthermore, the phototransistor array successfully replicates the scotopic and photopic adaptation recognition behaviors of the human retina. Notably, the device demonstrates faultless competency in image processing, achieving an impressive 93% accuracy for digit recognition. These findings contribute to the advancement of bionic neuromorphic chips and offer promising opportunities for future developments in the bioinspired visual system.

Effect of Light Intensity on the Relative Afferent Pupillary Defect in Unilateral Neuro-ophthalmic Pathology.

Objective pupillometry with standardized light intensities allows a comprehensive assessment of the relative afferent pupillary defect in patients with unilateral neuro-ophthalmic pathology. This study aimed to determine the impact of varying light intensities on the grade of relative afferent pupillary defect in unilateral neuro-ophthalmic pathology vis-à-vis healthy controls. Monocular pupillary light reflexes of 20 controls (14 to 50 years) and 31 cases (12 to 72 years) with clinically diagnosed relative afferent pupillary defect were measured thrice using 1-second-long light pulses, followed by 3 seconds of darkness, at eight light intensities (6.4 to 1200 lux) using objective pupillometry. The relative afferent pupillary defect was quantified as the ratio of the percentage change in the direct light reflexes of the left and right eyes. Its change with light intensity was described using standard exponential fits. The median (25th to 75th interquartile range) defect score of 54.8% cases decreased from baseline values of 1.58 (1.25 to 1.87) for right eye pathology and 0.45 (0.39 to 0.55) for left eye pathology to saturation values of 1.18 (1.05 to 1.31) and 0.98 (0.95 to 1.06), respectively, at light intensities between 56.9 and 300.5 lux. Like controls (1.01 [1.00 to 1.06]), the defect scores of the remaining 45.2% cases were constant with light intensity at 1.23 (1.18 to 1.46) and 0.87 (0.86 to 0.89) for right and left eye pathologies, respectively. Relative afferent pupillary defects may decrease with test light intensity in a significant proportion of patients with unilateral neuro-ophthalmic pathology. This highlights the importance of objective pupillometry with standardization light intensities for clinical assessment of afferent pupillary defects.

Designing CuInSe2 quantum dot-based high-performance Schottky photodetector: a numerical study

Sensing in the near-infrared and visible wavelengths is critically essential for a broad range of potential applications. Colloidal quantum dot(CQD) based photodetectors provide key advantages, such as spectral tuneability, straight integration with electronic parts, high sensitivity and low cost. Here, a Schottky photodiode architecture based on CuInSe2 (CISe) CQDs structure was designed and its photoresponse characteristics were simulated at various absorber layer thicknesses, at different back contact materials, varying light intensities, several defect densities, and different temperatures. A maximum responsivity of about 0.37 A W−1 was recorded from the proposed device. This work demonstrates that CISe CQDs are potential candidate materials for high-performance Schottky photodetectors operating in the near-infrared and visible electromagnetic spectrum.

All-fiber all-optical phase controller based on F-P interferometer and Er/Yb co-doped fiber

All-optical devices have attracted much attention for its potential applications in optical communication. In this letter, we propose an all-fiber all-optical phase controller based on an active Fabry-Perot interferometer (FPI) with Er/Yb co-doped fiber (EYDF). Two sections of EYDFs generate a large amount of heat under the pumping excitation of 973 nm, and achieve refractive index change and phase shift of F-P cavity via the thermo-optic effect. Experimental results show that the maximum phase shift of fabricated device is 2.53 π with a slope of 0.0167 π/mW, as well as the phase shift can be converted into the variations of light intensity by the interference characteristic of FPI, enabling optical switching with a rise time of 221 ms. The design of all optical fiber without material coating makes the device has advantages of simple manufacturing, small footprint, especially with good long-term environmental stability. We believe this scheme may provide a new platform for the investigation of all-fiber all-optical modulation, with potential applications in the field of tunable optical filters and Q-switched lasers.

The influence of spermidine on the build-up of fucoxanthin in Isochrysis sp. Acclimated to varying light intensities

Spermidine is a type of important growth regulator, which involved in the biosynthesis of photosynthetic pigments, and has the function of promoting cell proliferation. In this study, Isochrysis sp. was selected as the research object to explore the effects of spermidine supplementation on the growth of algal cells and fucoxanthin synthesis under different light intensities. The results showed that the cell density (5.40 × 106 cells/mL) of algae were the highest at 11 days under the light intensity of 200 μmol·m−2·s−1 and spermidine content of 150 μM. The contents of diadinoxanthin (1.09 mg/g) and fucoxanthin (6.11 mg/g) were the highest when spermidine was added under low light intensity, and the growth of algal cells and fucoxanthin metabolism were the most significant. In the carotenoid synthesis pathway, PDS (phytoene desaturase) was up-regulated by 1.96 times and VDE (violaxanthin de-epoxidase) was down-regulated by 0.95 times, which may promote fucoxanthin accumulation.

Ultracompact MXene V2C-Improved Temperature Sensor by a Runway-Type Microfiber Knot Resonator.

We demonstrate an all-fiber, compact-structure, high-sensing-efficiency temperature sensor using a resonator structure sensor device of a runway type and MXene V2C. The high-quality functional material MXene V2C, synthesized by a simple two-step method, has excellent photothermal conversion performance. As-prepared MXene V2C is integrated into the runway section of a runway-type microfiber knot resonator based on the coupling mechanism between the surface near the field of the fiber and materials. When the temperature variation range is ~25-70 °C, the corresponding transmission light intensity variation is linear, and the maximum normalized sensing efficiency is 2.21 dB/°C/mm. Our work demonstrates that the runway-type structure ensures the compactness of the sensor device and enhances the interaction distance between the material and the microfiber, which provides additional integration strategies for functional material-based sensor devices.

The effect of variable light intensity in luminescent-netting pots on the catch of snow crab (Chionoecetesopilio)

The use of light in pots has been shown to increase snow crab catch rates in eastern Canada and the Barents Sea, where better fishing efficiency could result in less fuel consumption, and financial and ecological benefits. However, some light characteristics necessary for maximizing efficiency have yet to be researched. The purpose of this study was to determine if there is a change in catch per unit effort (CPUE; number of snow crab per pot) and size selectivity of snow crab with varying light intensity. Three types of experimental luminescent-netting pots were used, each type with a different level of light intensity via the amount of phosphorescent strands woven into the pot netting, (either 2-, 4-, or 6-strands) and were compared to the traditional pot used in the fishery. There were mixed results among treatments, with the 2-strand pot catching fewer snow crab <103 mm carapace width (CW) and more snow crab ≥103 mm CW than the traditional pots, but overall, had a lower CPUE for legal and sub-legal sized males (14.8 and 3.1 per pot, respectively) than the traditional (16.1 and 5.5 per pot, respectively) when considering all size classes. When compared to the traditional, the 4-strand pot caught more legal and sub-legal (CPUE of 18.8 and 8.0 per pot, respectively) snow crab in terms of CPUE but caught fewer commercial snow crabs from 95 to 98 and 103–113 mm CW. The brightest intensity pots (6-strand) showed no significant difference in CPUE or size selectivity in comparison to the traditional. Increased light intensity pots either had no effect on snow crab capture (6-strand) or produced unwanted results (loss of commercial sizes, increase in sub-legal sizes). Conversely, the 2-strand pot showed decreases in juvenile crab catch and increases in the catch of the most valuable size-classes observed, which are attractive results to fisheries managers and harvesters, respectively. These results, combined with a large price increase, suggest that higher light-intensity pots are not attractive for the commercial fishery.