High Optical Density Research Articles

Effects of CO2 Aeration and Light Supply on the Growth and Lipid Production of a Locally Isolated Microalga, Chlorella variabilis RSM09

The Chlorophyceae algae, specifically Chlorella spp., have been extensively researched for biodiesel production. This study focused on the alga Chlorella variabilis RSM09, which was isolated from a brackish-water environment at Raksamae Bridge in Klaeng District, Rayong Province, Thailand. The effects of the carbon dioxide gas (CO2) concentration (0.03%, 10%, 20%, 30%, 40%, and 50% v/v), light intensity (3000, 5000, and 7000 Lux), and photoperiod (12:12, 18:6, and 24:0 h L/D) on algal growth and lipid production were investigated. The results indicated that C. variabilis RSM09 achieved optimal growth under 20% v/v CO2 aeration, with an optical density of approximately 2.91 ± 0.27, a biomass concentration of 1.32 ± 0.14 g/L, and a lipid content of 21.96 ± 0.29% (wt.). Among the three different light intensities, higher optical density (4.20 ± 0.14), biomass (1.79 ± 0.25 g/L), and lipid content (20.75 ± 2.0% wt.) were at the 5000 Lux of light intensity. Additionally, the photoperiod of 24:0 h (L/D) produced the highest biomass at 1.86 ± 0.21 g/L, followed by the 18:6 h light/dark photoperiod with a biomass of 1.65 ± 0.17 g/L, and the 12:12 h light/dark photoperiod with 1.35 ± 0.43 g/L. In contrast, the 18:6 h L/D photoperiod yielded a higher lipid concentration of 25.22 ± 2.06% (wt.) compared to the others. All cultured microalgae showed significant effects on fatty acid composition. Palmitic (16:0), linoleic (C18:2), and linolenic (C18:3) acids were predominant in C. variabilis RSM09 under all photoperiods. This study exhibited that the microalga C. variabilis RSM09 has great potential as a feedstock for biodiesel production.

New developments in intrinsic black photosensitive polyimide for advanced display applications

To meet the requirements of low power consumption, long endurance, and cost-efficiency for mobile phones, a polarizer-less technology (Pol-Less) OLED with a color-on-encapsulation (COE) structure has been proposed. In this groundbreaking technology, black photosensitive polyimide (PSPI) serves as the pixel definition layer (PDL) and plays a crucial role. However, the addition of inorganic pigments, such as carbon black, significantly compromises the dielectric insulation properties of the PDL. Therefore, exploring intrinsic black photosensitive polyimide with outstanding light shielding performance and high dielectric insulation properties has garnered increasing attention. In this study, a derivative of anthraquinone, namely 2,4,5,7-tetraamino-1,8-dihydroxyanthraquinone (4NADA) is incorporated into the photosensitive polyimide chains, successfully producing an intrinsic black photosensitive polyimide with broad absorption in the visible light range. Experimental results revealed that by copolymerizing 50 % moles of 4NADA in the diamines in the photosensitive polyamide acid ester, a black photosensitive polyimide with a high optical density (OD) of 0.89 and a relatively low dielectric constant of 3.6 at 1000 kHz was obtained. Furthermore.

Characterization of the immunodominant regions of Senecavirus A-VP1 structural protein via ELISA epitope mapping

Senecavirus A (SVA) is an RNA virus in the family Picornaviridae that has been detected in swine-production systems and is associated with vesicular disease and neonate mortality. The viral capsid is composed of four structural proteins: VP1–VP4. Although the VP1 protein has been reported to be the most immunogenic protein in vivo, no information on the immunodominant regions of the SVA polyprotein is available. The objective of this study was to identify the immunodominant regions of SVA polyprotein using an enzyme-linked immunosorbent assay (ELISA) epitope-mapping approach. The binding effect of SVA polyclonal antibody (SVA-pAb), SVA-VP1 monoclonal antibodies (SVA-mAb), and SVA-positive sera from clinically affected animals were characterized using a set of 18 overlapping SVA VP1-derived peptides by indirect and blocking ELISAs. All VP1 peptides yielded significant signal against SVA-pAb and SVA-VP1-mAb upon indirect ELISA. One peptide (aa 1–20) showed significantly high optical density on SVA recombinant VP1 protein (rVP1) and whole-virus-based indirect ELISAs. The blocking ELISA results demonstrated that peptides spanning aa 165–185 and 225–245 had a 50 % or greater inhibitory effect on SVA-pAb, while six groups of overlapping peptides spanning aa 1–35, 45–80, 90–140, 150–170, 195–230, and 240–264 and two groups of overlapping peptides spanning aa 1–50 and 60–264 showed a 50 % inhibitory effect or greater on swine VP1-mAb and SVA-seropositive swine serum, respectively, against SVA rVP1. Three-dimensional protein homology modeling showed that the peptides binding SVA-pAb are located on the outer surface of the viral capsid, while SVA mAbs and swine-positive sere can bind to epitopes located in both the inner and outer surfaces of the capsid. These linear epitopes showed differential binding and inhibitory activity on mAb and pAb; however, further studies will be necessary to evaluate whether they can act as decoy or neutralizing epitopes. Because mAb antibodies demonstrated a high binding affinity for this set of peptides, this information could lay the foundation for generating and screening specific antibodies for therapeutic potential.

In Vivo Lifetime Imaging of the Internal O2 Dynamics in Corals with near-Infrared-Emitting Sensor Nanoparticles.

Mapping of O2 with luminescent sensors within intact animals is challenging due to attenuation of excitation and emission light caused by tissue absorption and scattering as well as interfering background fluorescence. Here we show the application of luminescent O2 sensor nanoparticles (∼50-70 nm) composed of the O2 indicator platinum(II) tetra(4-fluoro)phenyltetrabenzoporphyrin (PtTPTBPF) immobilized in poly(methyl methacrylate-co-methacrylic acid) (PMMA-MA). We injected the sensor nanoparticles into the gastrovascular system of intact colony fractions of reef-building tropical corals that harbor photosynthetic microalgae in their tissues. The sensor nanoparticles are excited by red LED light (617 nm) and emit in the near-infrared (780 nm), which enhances the transmission of excitation and emission light through biological materials. This enabled us to map the internal O2 concentration via time-domain luminescence lifetime imaging through the outer tissue layers across several coral polyps in flowing seawater. After injection, nanoparticles dispersed within the coral tissue for several hours. While luminescence intensity imaging showed some local aggregation of sensor particles, lifetime imaging showed a more homogeneous O2 distribution across a larger area of the coral colony. Local stimulation of symbiont photosynthesis in corals induced oxygenation of illuminated tissue areas and formation of lateral O2 gradients toward surrounding respiring tissues, which were dissipated rapidly after the onset of darkness. Such measurements are key to improving our understanding of how corals regulate their internal chemical microenvironment and metabolic activity, and how they are affected by environmental stress such as ocean warming, acidification, and deoxygenation. Our experimental approach can also be adapted for in vivo O2 imaging in other natural systems such as biofilms, plant and animal tissues, as well as in organoids and other cell constructs, where imaging internal O2 conditions are relevant and challenging due to high optical density and background fluorescence.

Janus-Type Immunofluorescent Probes and a Quantitative Immunoassay System.

To realize highly sensitive immunoassays, high optical density probes conjugated with antibodies for target antigens have been demanded in order to increase the visibility of antigen-antibody complex formation. We herein demonstrate the development of an immunoassay system using magnetic and fluorescent Janus particles as probes in conjunction with an antibody-immobilized microfluidic device. The concentration of the detection limit at which there was a significant difference between SARS-CoV-2 and human coronavirus 229E antigens was 3.1 ng/mL, and the standard deviation of the signal was less than 5%. The immunofluorescent probe and immunoassay system developed in this study are expected to be applicable not only to SARS-CoV-2 but also to the quantitative measurement of various other disease marker proteins and biomolecules.

Discovering Dengue Virus Antibody Using Phage Display Technology

Dengue virus (DENV) is a type of flavivirus transmitted globally by the Aedes aegypti mosquito and is the causal agent of Dengue fever. Due to global warm-ing and rising temperatures worldwide, the rate of exposure to DENV is now reaching unprecedented levels, with over 400 million people getting infected each year. Despite worldwide attention to DENV, there is not currently an effective treatment or vaccine. Here, we focused on developing an antibody for the NS1 protein of the DENV, which enables earlier detection of disease and could further decrease the rate of death. Our study utilized a method more time-saving and cost-effective than the traditional method of extracting antibodies from the blood or B-cells of infected animals that show immu-nity: Phage Display. This technique allowed us to derive monoclonal antibodies (mAbs) from the genome library and select DENV antibodies that bind to antigen proteins. In this study, we used Phage Display to select ninety-six potential antibodies from three phases of panning, which then went through indirect ELISA screening for optical density (OD) confirmation (OD > 1.5). Sixteen of the high optical density antibodies were sent to a DNA sequencing analysis facility where fifteen of them were revealed to be the same 1G1 strain. By understanding how antibodies are discovered using phage display technology, we hope to advance the field with reevaluation of current vaccines and the development of novel ones.

"Nonperturbative Nonlinearities": Perhaps Less than Meets the Eye.

We address challenges in characterizing changes in permittivity and refractive index beyond standard perturbative methods with special attention given to transparent conductive oxides (TCOs). We unveil a realistic limit to permittivity changes under high optical power densities. Our study covers both slow and ultrafast nonlinearities, demonstrating that all nonlinearities induce refractive index changes accurately described by a simple curve with saturation electric field (or irradiance) and maximum change of permittivity at saturation. Our model, grounded in material properties, like oscillator strength and characteristic times, offers a robust framework for understanding and predicting nonlinear optical phenomena in TCOs and other materials. We differentiate between the significance of higher-order nonlinear susceptibilities in ultrafast and slow nonlinear scenarios. We aim to provide valuable insights for researchers exploring strong light-matter interaction.

Heparin-induced thrombocytopenia with very high antibody titer is associated with slower platelet recovery and higher risk of thrombosis.

Heparin-induced thrombocytopenia (HIT) is a prothrombotic disorder mediated by platelet-activating antibodies targeting platelet factor 4 (PF4) and heparin complex. A higher antibody titer is reflected in a higher optical density (OD) by enzyme-linked immunosorbent assay for heparin-PF4 antibodies. This single-institution retrospective study of 116 HIT patients examined the effect of heparin-PF4 OD on time to platelet recovery, vascular thrombosis, and in-hospital mortality. Patients were divided into 3 cohorts based on heparin-PF4 OD: cohort 1 had an OD ≥ 2 and ≤ 2.4, cohort 2 had an OD > 2.4 and ≤ 2.8, and cohort 3 had an OD > 2.8. A higher OD titer was associated with significantly increased time to platelet recovery when compared between cohorts 1 versus 2 (HR = 0.599, p = 0.0221) and 1 versus 3 (HR = 0.515, p = 0.0014), as well as an increased risk of thrombosis (79.4%-cohort 3 vs 53.8%-cohort 2 vs 46.1%-cohort 1, p = 0.04), but had no impact on mortality (2.62-alive vs 2.65-deceased, p = 0.7432). A higher OD titer can inform risk assessment and support decision-making in HIT patients; however, prospective studies are needed to further clarify the impact of heparin-PF4 OD on outcomes.

Sustainable and eco-friendly production of biodiesel from Chlorella vulgaris supplemented with biogenic calcium oxide nanoparticles derived from Ulva intestinalis and eggshell as precursors

Biodiesel derived from microalgae has the potential to be a sustainable fuel. Eggshell waste is rich in vital compounds, but still creates pollution problems, due to being discarded in the landfills without any treatment. This study aims to convert eggshells to CaCl2 and use CaCl2 derived from eggshells to biogenic CaO-NPs. Tested the impact of CaCl2, CaCl2 derived from eggshells, and biogenic CaO-NPs, as supplementation to the BG11 media on the growth and lipids yield of Chlorella vulgaris green alga. This study used Ulva intestinalis green alga to synthesize (Ui-CaO-NPs). The characterizations of Ui-Ca-ONPs were analyzed by EDS, XRD, zeta potential, FT-IR, and TEM. Chlorella vulgaris cultivated in modified BG11 media that was supplemented by different concentrations of CaCl2, CaCl2 derived from eggshell, and Ui-CaO-NPs as eggshell precursors (0.009, 0.018, and 0.036 g/L). The low concentrations of CaCl2 as eggshell precursors possessed high optical density, dry weight, and lipids contents of C. vulgaris. The best Chlorophyll a and b contents were obtained with Ui-CaO-NPs (0.018 g/L). The highest carotenoid content was obtained with alga grown in a medium containing 0.036 g/L CaCL2 the GC.Ms. analysis possessed the high-quality lipids profile obtained with C. vulgaris cultivated in media containing 0.018 g/L Ui-CaO-NPs. Eggshells can be used as sources of CaCl2 and CaO-NPs for different applications as eco-friendly and economical materials.

Synthesis, characterization and photocatalytic performance of polyvinyl alcohol/zinc oxide nanocomposites: A comprehensive study

The present work presents a detailed study on the synthesis and characterization of ZnO and PVA/ZnO nanoparticles using a bottom-up chemical precipitation method. The study found that the incorporation of polyvinyl alcohol (PVA) in ZnO induced a reduction in the XRD peak intensity due to mixed phases on the surface of the nanoparticles. Both ZnO and PVA/ZnO nanoparticles exhibited a non-uniform size distribution below 50 nm, with PVA/ZnO showing a higher dislocation density and microstrain distribution. Using deformation models, Young's modulus equation revealed that PVA/ZnO experiences higher stress values, but also possesses a greater energy density than pure ZnO. The optical properties of the ZnO and PVA/ZnO nanoparticles exhibited bandgaps of 3.14 and 3.09 eV, respectively. The refractive index was found to be influenced by the electronic structure of the material, which wasin turn governed by the bandgap. PVA passivation enhanced the optical quality of ZnO by reducing the non-radiative recombination of charge carriers, leading to improved absorption and higher optical density. TEM analysis revealed that the nanoparticles are polycrystalline and have a pebble-like shape with a size distribution that is less than 49 nm. The study compared the photocatalytic efficiency of PVA/ZnO and pure ZnO nanoparticles in the degradation of crystal violet dye and found that PVA/ZnO exhibited a slightly lower efficiency (48 %) compared to pure ZnO (49 %) after 90 min, with reaction rates of 0.00694 and 0.00747, respectively, indicating a comparable performance despite the presence of PVA. The study exhibits promising applications in optoelectronic-driven environmental remediation processes.

P‐151: The Optimization of Quantum‐Dots Color Filter for Flexible Display Applications

This paper introduces a flexible and uniformly‐dispersed quantum dot (QD) color filter (QDCF) fabricated for micro‐LED by photolithography. We studied the condition of PET films and concentration of QDs, the optimized QDCF exhibited high quantum yield (QY) up to over 70%, and a high optical density (OD) over 1.2. The QY increased and then decreased with the increase of the concentration.

12‐3: Materialization of Mid‐Resolution Quantum Dot Color Converters on G2.5 TFT‐LCD Production Line for Micro‐LED Displays

This study proposes a mass production solution for quantum dot color converter (QDCC) of mid‐resolution micro‐LED displays. Therefore, a gray bank materials and QD photoresist (PR) with high optical density (OD) and low film thickness were developed. The gray bank materials can achieve OD = 1.08 and a reflectivity of over 25% at a thickness of 4 μm. The red QDPR has OD = 1.93 at 3 μm, and the green QDPR has OD = 1.58 at 3.3 μm. Finally, a 125 PPI and 7‐inch QDCC were fabricated using a G2.5 TFT‐LCD production line, and the optimal material formula and process conditions were determined. Optical analysis shows color point uniformity with STD < 1.3%, indicating that this solution can provide excellent in‐plane uniformity.

Enhancing light absorption of deep ultraviolet photodiodes through intelligent algorithm-guided design of resonant nano-optical structures

The surface of the deep ultraviolet (DUV) photodiodes requires an enhanced light absorption to improve wall-plug efficiency. The resonant Mie scatterer has a high optical mode density with a high refractive index all-dielectric resonant structure, which causes strong light coupling and improves forward scattering, providing a new perspective for efficient light absorption on the surface of the DUV photodiodes. In this work, a method is proposed for the design of nano-optical structures that is capable of supporting forward light scattering across the resonant bandwidth. This is achieved by utilizing intelligent algorithms in conjunction with Maxwell’s equations. The results show that the average light absorption coefficient of the optimized optical structure is improved to more than 96% with angle-independent and polarization-independent characteristics. Based on intelligent algorithms, a reverse design approach can be employed to maximize this effect, thereby offering novel avenues for enhancing the wall-plug efficiency of the DUV photodiodes.

Efficient Low-Temperature Nutrient Removal from Agricultural Digestate Using Microalgae

Humanity is facing an energy crisis triggered by the depletion of fossil fuels, rapid industrialization, and the growthof the global population. These trendsput an emphasis on searching for alternative energy sources. Additionally, the rising concentration of carbon dioxide in the atmosphere is driving climate change, which poses serious threats. In this scenario, microalgae emerge as a promising solution for both sustainable energy production and CO2 sequestration. Digestate, a nutrient-rich by-product of anaerobic digestion, is considered a cost-effective nutrient source for microalgae cultivation. Utilizing digestate not only enhances the sustainability and economic feasibility of microalgal biofuels but also offers a method for wastewater treatment. Nevertheless, the application of digestate is limited by its high optical density and substantialamount of total solids.In this study, several pretreatment methods were tested to increase the feasibility of digestate application for microalgae cultivation. Our findings show that various centrifugation methods and vacuum filtration decrease the content of total solids but are not effective in reducing optical density. Although the use of microalgae in treating various wastewaters has shown promising outcomes, the effectiveness of nutrient removal at low temperatures remainslargely unexplored.To fill this gap, green microalga Chlorella sorokiniana was cultivated in pretreated diluted liquid digestate in dynamic springtime weather conditions in a covered open race-way pond integrated into a biogas plant.During the cultivation, high solar irradiance and low temperatures were recorded resulting in suboptimal conditions for C. sorokinianagrowth. Although low productivity of C. sorokiniana was detected, the nutrient removal efficiency was high. C. sorokiniana could efficiently remove 83% of nitrogen and 85% of phosphorus showing very promising results of the use of microalgae for wastewater treatment in high latitude regions.

Optimized Wide-Angle Metamaterial Edge Filters: Enhanced Performance with Multi-Layer Designs and Anti-Reflection Coatings

Optimized Wide-Angle Metamaterial Edge Filters: Enhanced Performance with Multi-Layer Designs and Anti-Reflection Coatings

Food waste recycling to Yarrowia biomass due to combined hydrothermal carbonization and biological treatment

Food waste (FW) to value-added application represents a demanding opportunity in the circular economy. As one of the approaches, FW hydrothermal carbonization (HTC) delivers an aqueous phase (HTC-AP), which would be suitable when applied to microbial growth and lipid production. In this context, this current work explored HTC-AP from FW obtained through HTC (temperatures 200 to 260 °C) for microbial growth of 14 different Yarrowia species. Among these strains, Y. lipolytica, Y. keelungensis, Y. porcina, and Y. galii showed the ability to utilize HTC-AP. In HTC from 200 °C high optical density (OD600) reaching above 1.2 for the 4 species was observed. An increase in the temperature by 20 °C declined the growth of Y. lipolytica, Y. porcina, and Y. galii by 17%. However, Y. keelungensis showed good growth regardless of the HTC temperature. Further, the lipid produced better at higher biomass 240 °C compared to 260 °C during the HTC. Further, Y. yakushimensis showed the highest growth rate among all the analyzed media (0.12 – for medium 2 (0.45 NH4+ and 200 °C). Although the composition of HTC-AP is very diverse and often toxic, some analyzed yeast species can use the contained compounds as a carbon source for biomass and lipid biosynthesis. The presented possibilities are a very good starting point for developing processes on a larger scale.

Spectral imaging based on custom-made multi-strip filter arrays

Spectral imaging technology based on on-chip spectroscopy can find applications in areas including aerospace, industrial and consumer electronics, and so on. Since each application normally requires a different set and number of spectral bands, the development of customized spectroscopy solutions with more compact size and lower cost becomes quite important. In this paper, we demonstrate a compact, highly customizable imaging spectrometer scheme based on custom-made multi-strip filter arrays, which maintains an average high transmission of ∼85%, narrow bandwidth of ∼30nm, and high optical density of ∼OD2 in the blocking regions across the visible to near-infrared waveband. Spectral imaging experiments are conducted, and the accurate reconstruction of sparse spectral image data is demonstrated as well to prove the validity of the proposed scheme. As a result, the work reported in this paper allows researchers to develop customized spectral imaging equipment in a relatively easy way and also has a great potential to be engineered further for scalable production with a quite low cost.

CA1 Modulates the Osteogenic Differentiation of Dental Follicle Stem Cells by Activating the BMP Signaling Pathway In Vitro.

Carbonic anhydrase 1 (CA1) has been found to be involved in osteogenesis and osteoclast in various human diseases, but the molecular mechanisms are not completely understood. In this study, we aim to use siRNA and lentivirus to reduce or increase the expression of CA1 in Dental follicle stem cells (DFSCs), in order to further elucidate the role and mechanism of CA1 in osteogenesis, and provide better osteogenic growth factors and stem cell selection for the application of bone tissue engineering in alveolar bone fracture transplantation. The study used RNA interference and lentiviral vectors to manipulate the expression of the CA1 gene in DFSCs during in vitro osteogenic induction. The expression of osteogenic marker genes was evaluated and changes in CA1, alkaline phosphatase (ALP), Runt-related transcription factor 2 (RUNX2), and Bone morphogenetic proteins (BMP2) were measured using quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting (WB). The osteogenic effect was assessed through Alizarin Red staining. The mRNA and protein expression levels of CA1, ALP, RUNX2, and BMP2 decreased distinctly in the si-CA1 group than other groups (p < 0.05). In the Lentivirus-CA1 (LV-CA1) group, the mRNA and protein expressions of CA1, ALP, RUNX2, and BMP2 were amplified to varying degrees than other groups (p < 0.05). Apart from CA1, BMP2 (43.01%) and ALP (36.69%) showed significant upregulation (p < 0.05). Alizarin red staining indicated that the LV-CA1 group produced more calcified nodules than other groups, with a higher optical density (p < 0.05), and the osteogenic effect was superior. CA1 can impact osteogenic differentiation via BMP related signaling pathways, positioning itself upstream in osteogenic signaling pathways, and closely linked to osteoblast calcification and ossification processes.

Fabrication of Single-Layer Resonant Infrared Filters With High Optical Density

Fabrication of Single-Layer Resonant Infrared Filters With High Optical Density

Effectiveness of the Drought-tolerant Plant Growth Promoting Rhizobacteria (PGPR) that Supports Paddy Growth in Drought Condition

Drought stress is the primary constraint on plant-based food production, particularly paddy production. Several studies have examined plant resistance to heat and osmotic pressure. This study aimed to isolate bacteria with plant growth-promoting properties that could tolerate high temperatures and improve paddy growth during drought. Five isolates with a high optical density value (OD600) at 30% PEG 6000 (equivalent to -1.03MPa) and able to grow at high temperatures were identified based on the 16S rRNA gene sequences as Achromobacter spanius UKM UR10, Bacillus pumillus UKM UR11, Bacillus cereus UKM R66, and Bacillus altitudinis UKM RB11, which were isolated from the root, where as Bacillus sp. UKM S8 was isolated from rhizosphere soil. These isolates exhibited 1-amino cyclopropane-1-carboxylate (ACC) deaminase activities ranging between 1.01 and 1.12 mmol α-ketobutyrate mg-1 protein h-1, which degraded ACC to α-ketobutyrate and ammonia. Other plant growth promoters assessed include indole acetic acid (IAA; concentration between 9.69 and 13.15µg/ml) and phosphate solubilization (concentrations between 31.74 and 51.30 mg/l) production. Subsequently, the selected plant growth-promoting rhizobacteria (PGPR) were incorporated as a consortium and inoculated on paddy seeds, thus increasing total chlorophyll, proline, and soluble sugar content in paddy subjected to drought-stress conditions. Paddy yield components and performances, such as panicle number, spikelet number, dry grain weight, number of leaves, stalk length, and root length increased significantly. This isolated PGPR exhibits heat resistance, promotes plant growth, and can serve as an inoculant for paddy plants under drought conditions.