High Optical Density Research Articles

Quantum gas magnifier for sub-lattice-resolved imaging of 3D quantum systems

Imaging is central to gaining microscopic insight into physical systems, and new microscopy methods have always led to the discovery of new phenomena and a deeper understanding of them. Ultracold atoms in optical lattices provide a quantum simulation platform, featuring a variety of advanced detection tools including direct optical imaging while pinning the atoms in the lattice1,2. However, this approach suffers from the diffraction limit, high optical density and small depth of focus, limiting it to two-dimensional (2D) systems. Here we introduce an imaging approach where matter wave optics magnifies the density distribution before optical imaging, allowing 2D sub-lattice-spacing resolution in three-dimensional (3D) systems. By combining the site-resolved imaging with magnetic resonance techniques for local addressing of individual lattice sites, we demonstrate full accessibility to 2D local information and manipulation in 3D systems. We employ the high-resolution images for precision thermodynamics of Bose–Einstein condensates in optical lattices as well as studies of thermalization dynamics driven by thermal hopping. The sub-lattice resolution is demonstrated via quench dynamics within the lattice sites. The method opens the path for spatially resolved studies of new quantum many-body regimes, including exotic lattice geometries or sub-wavelength lattices3–6, and paves the way for single-atom-resolved imaging of atomic species, where efficient laser cooling or deep optical traps are not available, but which substantially enrich the toolbox of quantum simulation of many-body systems.

A Thrombospondin-1 Release Assay (TRA) Coupled to PF4-Treated Cryopreserved Platelets for the Detection of Pathogenic HIT and VITT Antibodies

Background: Platelet-activating anti-PF4 antibodies that cause thrombocytopenia and thrombosis are implicated in Heparin-induced thrombocytopenia (HIT) and, more recently, in a newly recognized entity, vaccine-induced immune thrombotic thrombocytopenia (VITT). Current frontline PF4-Polyanion ELISAs utilize simple techniques but are highly non-specific. Functional gold-standard assays such as the serotonin-release assay (SRA) and PF4-dependent P-selectin expression assay (PEA) have limited availability due to technical complexity and the requirement for freshly-drawn normal donor platelets which results in significant delays in diagnosis. Thus, there is an unmet need for near-patient, functional assays for HIT/VITT diagnosis.Aim: To develop a highly sensitive and specific functional assay to detect platelet-activating antibodies associated with HIT and VITT using long-term stored platelets. The assay should be technically simple, avoiding current functional HIT testing endpoints such as aggregometry, radioactivity measurement or flow cytometry.Methods: Platelets were subjected to controlled-rate freezing in a trehalose-based buffer. Cryopreserved platelets were then thawed after variable storage periods, incubated with platelet factor 4 (PF4), and sera from HIT or VITT suspected patients. Thrombospondin-1 (TSP1), a protein highly expressed in platelet α-granules, was quantified from activated platelet supernatants in an ELISA-based assay as a measure of platelet activation.Results: In initial studies, p-selectin expression was induced by platelet-activating HIT antibodies using cryopreserved platelets and the TSP1-release assay (TRA) detected HIT antibody-mediated PF4-dependent cryopreserved platelet activation across 20 different platelet lots (data not shown). A representative study using platelets stored for 11 months is shown in Figure 1A. A cohort of thirty-six HIT-suspected patient sera, half with PF4-dependent platelet-activating antibodies (PEA+) and without (PEA-), were used to evaluate the diagnostic accuracy of the TRA (Figure 1B). All 18 PEA+ samples activated platelets strongly with a mean TSP1 concentration of 147 µg/mL measured in the supernatant compared to a mean of 43 µg/mL obtained with non-activating samples. TSP1 release in a subgroup of 7 PEA+/SRA+/ELISA+ and 4 PEA-/SRA-/ELISA+ samples that were matched for ELISA Optical Density was examined (Figure 1C). Results demonstrated that even strong ELISA+ samples that were non-activating (PEA-/SRA-) did not induce platelet activation in the TRA, confirming high specificity of the assay. The TRA was tested for its ability to detect platelet-activating antibodies in four patients who developed VITT after the Janssen vaccine (Ad26.COV2.S). All samples induced high levels of TSP1 release from cryopreserved platelets (Figure 1D).Conclusions: Our results demonstrate that cryopreserved platelets stored for several months are viable and capable of degranulation upon activation. Further, we demonstrate that measurement of TSP-1 released from cryopreserved, PF4-treated platelets is highly accurate for detecting platelet-activating HIT and VITT anti-PF4 antibodies. Specificity and sensitivity were both 100% even with samples that were strongly false-positive in the HIT ELISA. Coupling cryopreserved platelet activation to a simple ELISA endpoint, as demonstrated here, precludes the need for fresh platelets and complex testing techniques. Thus, the TRA has the potential to transform the diagnostic testing paradigm in HIT and VITT by making near-patient in-hospital functional testing available for rapid and accurate diagnosis.Figure Legend:Figure 1. TSP-1 quantification of (A) 3 HIT patient samples (closed circles) relative to 3 normal control samples (open circles) after 11-months of frozen platelet storage. (B) Thirty-six HIT-suspected patient samples: 18 PEA+ samples (closed circles), and 18 PEA- samples (open squares). Data are compared using two-tailed, unpaired Student's t test. **** P<0.0001. (C) Eleven high optical density matched HIT ELISA patient sera: 7 PEA+/SRA+ samples (closed circles) and 4 PEA-/SRA- samples (open squares). (D) TSP-1 quantification of VITT patient sera. NC-normal control. [Display omitted] DisclosuresPruthi: Instrumentation Laboratory: Honoraria; HEMA Biologics: Honoraria; Bayer Healthcare AG: Honoraria; Genentech: Honoraria; CSL Behring: Honoraria; Merck: Honoraria. Padmanabhan: Veralox Therapeutics: Membership on an entity's Board of Directors or advisory committees.

Purification of native histidine-rich protein 2 (nHRP2) from Plasmodium falciparum culture supernatant, infected RBCs, and parasite lysate

BackgroundDespite the widespread use of histidine-rich protein 2 (HRP2)-based rapid diagnostic tests (RDTs), purified native HRP2 antigen is not standardly used in research applications or assessment of RDTs used in the field.MethodsThis report describes the purification of native HRP2 (nHRP2) from the HB3 Plasmodium falciparum culture strain. As this culture strain lacks pfhrp3 from its genome, it is an excellent source of HRP2 protein only and does not produce the closely-related HRP3. The nHRP2 protein was isolated from culture supernatant, infected red blood cells (iRBCs), and whole parasite lysate using nickel-metal chelate chromatography. Biochemical characterization of nHRP2 from HB3 culture was conducted by SDS-PAGE and western blotting, and nHRP2 was assayed by RDT, ELISA, and bead-based immunoassay.ResultsPurified nHRP2 was identified by SDS-PAGE and western blot as a − 60 kDa protein that bound anti-HRP-2 monoclonal antibodies. Mouse anti-HRP2 monoclonal antibody was found to produce high optical density readings between dilutions of 1:100 and 1:3,200 by ELISA with assay signal observed up to a 1:200,000 dilution. nHRP2 yield from HB3 culture by bead-based immunoassay revealed that both culture supernatant and iRBC lysate were practical sources of large quantities of this antigen, producing a total yield of 292.4 µg of nHRP2 from two pooled culture preparations. Assessment of nHRP2 recognition by RDTs revealed that Carestart Pf HRP2 and HRP2/pLDH RDTs detected purified nHRP2 when applied at concentrations between 20.6 and 2060 ng/mL, performing within a log-fold dilution of commercially-available recombinant HRP2. The band intensity observed for the nHRP2 dilutions was equivalent to that observed for P. falciparum culture strain dilutions of 3D7 and US06 F Nigeria XII between 12.5 and 1000 parasites/µL.ConclusionsPurified nHRP2 could be a valuable reagent for laboratory applications as well as assessment of new and existing RDTs prior to their use in clinical settings. These results establish that it is possible to extract microgram quantities of the native HRP2 antigen from HB3 culture and that this purified protein is well recognized by existing monoclonal antibody lines and RDTs.Graphical

Development of a probiotic for animals and aquaculture based on Bacillus toyonensis B-13249 and Bacillus pumilus B-13250 strains

Abstract: This article aims to develop a probiotic for animals and aquaculture based on the Bacillus toyonensis B-13249 and Bacillus pumilus B-13250 strains. The selection of a nutrient medium was conducted for cultivating the inoculum of these microorganisms. Several bacteria fermentations of the Bacillus genus were performed in biological reactors with a capacity of 15 and 250 l. A technology for obtaining a finished probiotic for animals and aquaculture was developed. The results indicate that L-broth is the most optimal nutrient medium for cultivating the studied strains. The cultivation of B. toyonensis B-13249 and B. pumilus B-13250 strains in fermenters revealed that sporulation begins after 4–8 hours of fermentation. In contrast to the vegetative medium, the fermentative medium helped the bacilli develop a higher optical density (the maximum value in the B. pumilus strain – 2.400±0.149), pH value (maximum value in the B. toyonensis strain – 8.483±0.609) and titer (at least 1010 CFU/g). After 20–24 hours of incubation, both strains of bacilli in the fermenter, almost completely pass into endospores, which serve as a signal for the start of biomass centrifugation. This was indicated by the following: from a 15 l fermenter – 83.3±6.1 g of concentrate, from a 250 l fermenter – 499.8±51.4 g. The number of bacilli in a concentrated state was at least 1·1011 CFU/g for both strains. Obtaining a finished preparation required mixing bacterial concentrates with maltodextrin to a titer of at least 1·1010 CFU/g. The number of bacteria in the preparation checked every month during the year, recorded no value less than 1·1010 CFU/g. Thus, L-broth is most favorable for growing the mother culture of the B. toyonensis B-13249 and B. pumilus B-13250 strains, and fermentative nutrient medium – for the cultivation in fermenters. The expiry date of the bacilli-based biological preparation is at least 12 months, during which the drug’s polycomponence, color and consistency are preserved, in addition to the bacteria titer (at least 1·1010 CFU/g) and their viability.

Successful venous thromboprophylaxis in a patient with vaccine-induced immune thrombotic thrombocytopenia (VITT): a case report of the first reported case in Thailand

BackgroundVaccine-induced immune thrombotic thrombocytopenia (VITT) is a rare but fatal complication of the Coronavirus Disease 2019 vaccine. The many reports of VITT have mostly been in the Caucasian population. Here, we present the first reported case in an Asian population.Case presentationA 26-year-old female had severe headache and severe thrombocytopenia 8 days after administration of the ChAdOx1 nCoV-19 vaccine developed by AstraZeneca. Although no thrombosis was demonstrated by imaging studies, she had very highly elevated d-dimer levels during hospitalization. Serology for antibodies against platelet factor 4 was positive on several days with very high optical density readings. We found that the antibody could induce spontaneous platelet aggregation without the presence of heparin. We decided to treat her with intravenous immunoglobulin, high-dose dexamethasone, and a prophylactic dose of apixaban. She improved rapidly and was discharged from the hospital 6 days after admission. Neither thrombocytopenia nor thrombosis was subsequently detected at the three-week follow-up.ConclusionsDespite the lower rate of thrombosis, VITT can occur in the Asian population. Early detection and prompt treatment of VITT can improve the patient’s clinical outcome. Thromboprophylaxis with nonheparin anticoagulants also prevents clot formation.

Construction of pillar[5]arene-based photochromic supramolecular polymeric system with tunable thermal bleaching rate

Naphthopyran is targeted as the photochromic material here due to its fast photo-sensitivity, high optical density, relative chemical structural simplicity, and its colorless degradation products are also important in commercial ophthalmic applications as variable transmission lenses. In this paper, we reported the synthesis and characterization of a new class of photochromic supramolecular system containing both pillar[5]arene subunit and naphthopyran moiety in the chemical structural backbone. Owing to the supramolecular host-guest interactions of pillar[5]arene/neutral nitrile molecular recognition motif, the designed molecules could be spontaneously self-assembled. Thus, the photochromic supramolecular system indicates an efficient photochromism with convenient tunable fading rate, providing a simple and versatile strategy to fabricate photochromic supramolecular system, as well as potential applications in advanced photo-responsive materials.

Removal of pentachlorophenol from contaminated wastewater using phytoremediation and bioaugmentation processes.

The phytoremediation procedure was conducted by Lemna gibba (L) and Typha angustifolia (T) and the bioaugmentation procedure used P. putida HM627618. The ability of the selected P. putida HM627618 to tolerate and remove PCP (200 mg L-1) was measured by high performance liquid chromatography analysis and optical density at 600 nm. Five different experiments were conducted in secondary treated wastewater for PCP testing removal (100 mg L-1) including two phytoremediation assays (T + PCP; L + PCP), three bioaugmentation-phytoremediation assays (T + B + PCP; L + B + PCP; L + T + B + PCP) and a negative control assay with PCP. Various analytical parameters were determined in this study such as bacterial count, chlorophylls a and b, COD, pH and PCP content. The main results showed that the average PCP removal by P. putida HM627618 was around 87.5% after 7 days of incubation, and 88% of PCP removal was achieved by treatment (T + B) after 9 days. During these experiments, pH, COD and chloride content showed a net increase in all treatments. The chlorophylls a and b in case of (T) and (L) Chlorophylls a and b for T and L phytoremediation showed a decrease with a value less than 10 μg/mg of fresh material after 20 days of cultivation.

Heparin‐induced thrombocytopenia in end‐stage renal disease: Reliability of the PF4‐heparin ELISA

BackgroundDiagnosing heparin‐induced thrombocytopenia (HIT) in patients with end‐stage renal disease (ESRD) can be difficult, as they are frequently exposed to heparin and have multiple etiologies for thrombocytopenia. ObjectiveTo correlate 4T scores, IgG heparin–platelet factor 4 (PF4‐heparin) ELISA results, and serotonin release assay (SRA) results in patients with ESRD. MethodsWe performed a retrospective review of patients with ESRD (creatinine clearance < 15 mL/min or on renal replacement therapy [RRT]) who underwent PF4‐heparin ELISA testing from October 2015 to September 2019. True‐positive PF4s required an intermediate to high 4T score (≥4), a positive SRA, and receipt of treatment for a HIT diagnosis. False‐positive PF4s were defined as a positive PF4 with a negative SRA, low 4T score (<4), or lack of treatment for HIT. Indeterminant cases were classified on the basis of clinical assessment by the treating team (eg, hematology or vascular medicine). ResultsOf 254 patients with ESRD (92% on RRT), 29 patients (11.4%) had a positive PF4. Eleven (37.9%) had a confirmed diagnosis of HIT: 10 patients who met all of the above criteria, and one who met the 4T criteria and was treated for HIT but did not have SRA testing due to high clinical suspicion and a positive PF4 test. False‐positive PF4 values occurred in 8 patients (27.5%). Of 10 (34.5%) indeterminant cases of patients with a negative SRA but intermediate to high 4T and positive PF4, only 3 patients were treated for HIT, whereas the other 7 were judged not to have HIT as assessed by the treating clinician. In patients with an intermediate to high 4T score and PF4 optical density > 0.4 but negative SRA, who were not treated for HIT, there were no adverse outcomes documented such as new or progressive thrombosis. ConclusionIn our ESRD population, 4T scores and PF4 testing were not predictive of a clinical diagnosis of HIT.

Heparin-Induced Thrombocytopenia with Very High Antibody Titer Is Associated with Slower Platelet Recovery

Introduction: HIT is a relatively common and potentially catastrophic prothrombotic disorder caused by platelet activating antibodies targeting complexes of platelet factor 4 (PF4) and heparin. Diagnosis rests on clinical features coupled with serologic assays, most commonly an ELISA for heparin-PF4 antibodies. The ELISA optical density (OD) is a surrogate for antibody titer, an OD < 1 conveying a likelihood for pathogenic platelet-activating antibodies of < 1%, while OD > 2.0 confirms clinically suspected platelet activating antibodies in about 90%. The treatment for HIT is alternative anticoagulation, effecting platelet recovery >100,000 usually within 3 days and in the great majority within 7 days. We and others have observed very delayed platelet recovery (sometimes for weeks; “persisting HIT”) and this appeared more common with high titer antibodies. We did a retrospective analysis of 116 patients with HIT from single institution to investigate whether high titres of antibodies in HIT is associated with prolong time to platelet recovery and its potential impact on overall survival.Method: We retrospectively reviewed 116 patients diagnosed with HIT in our institution from 2009 to 2017 using our hospital database. Charts were reviewed for clinical comorbidities, association of surgery, thromboembolic events, type of alternative anticoagulation used on HIT diagnosis, platelet nadir count and time to recovery, and the relationship to ELISA OD. For statistical analysis, patients with HIT were categorized into 3 cohorts based on OD 1 to OD equal or less than 2.5, OD 2.5 to OD equal or less than 3 and OD more than 3 (Table 1). Patients with OD less than or equal to 2.5 was chosen as the reference group. A competing risk analysis based on the Fine & Gray method investigated differences in cumulative incidence of platelet recovery among the cohorts. Death before recovery was treated as a competing risk. Pooled t- test analysis was used to study correlation between OD and survival.Results: Median age of 116 patients was 65 years (63-68 ; 95% CI). 60.3% of the patients were male. Median value of initial platelet count during admission was 212k. Median value of nadir platelet count after diagnosis of HIT was 47k. 90% had surgery prior to diagnosis of HITT. 57% of patients with HIT had thromboembolic disease. 53%; 15% and 9% of patients were transitioned to Coumadin, NOACs and Arixtra respectively after initially getting treated with alternative anticoagulation Bivalirudin for HIT. Out of 116 patients, 101 patients (87%) of patients had platelet recovery in median of 6 days. The heparin OD value is significantly different between the two cohorts (p=0.0485) based on a pooled t-test. We further categorized all the patients into 3 cohorts based on their PF4 OD to study its impact on time to platelet recovery as shown in Table 1.There was no significant difference in recovery time between patients with OD between 2.5 and 3.0 and those less than 2.5 (p = 0.7207). The estimated hazard ratio of 0.921 [95% CI: (0.588, 1.444)], implying that patients with a higher OD value were likely to take slightly longer to recover their platelet count. However there was a statistically significant difference in platelet recovery time for patients OD greater than 3.0 (p = 0.0260) with hazard ratio 0.598 [95% CI: (0.380, 0.940)] compared to the reference group (see Figure 1). In-hospital mortality was 24.14% (28 patients) but was not significantly different by ELISA OD (p=0.7432). There is ongoing analysis of relationship of ELISA OD to thrombotic complications.Conclusion: Time to platelet recovery was significantly increased in HIT patients with heparin-PF4 OD value > 3. The lack of impact on overall survival probably relates to the fact that most deaths with HIT are related to underlying disorders (multiorgan failure, severe cardiac disease, cancer) rather than complications of HIT per se. A larger prospective study might further clarify the impact of PF4 OD on HIT treatment and outcomes. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

The first known case of vaccine‐induced thrombotic thrombocytopenia in Australia

The first known case of vaccine‐induced thrombotic thrombocytopenia in Australia

Performance characteristics of platelet autoantibody testing for the diagnosis of immune thrombocytopenia using strict clinical criteria.

Misclassification of immune thrombocytopenia (ITP) is common, which might undermine the value of platelet autoantibody testing. We determined the sensitivity and specificity of platelet autoantibody testing using the direct antigen capture assay for anti-glycoprotein (GP) IIb/IIIa or anti-GPIbIX in patients with 'definite ITP', defined as those with a documented treatment response. Sensitivity of platelet autoantiboody testing increased from 48·3% [95% confidence interval (CI) 43·5-53·2] for all ITP patients to 64·7% (95% CI 54·6-73·9) for definite ITP patients. Specificity was unchanged [75·3% (95% CI 67·5-82·1)]. High optical density values (>0·8) improved the specificity of platelet autoantibody testing but lowered sensitivity. In patients with a high pretest probability, platelet autoantibodies can aid in the diagnosis of ITP and may be most prevalent in certain patient subsets.

Finding balance with deep eutectic solvents: High concentrations and improved conductivities for the off-the-shelf nitroxide TEMPOL

Viologens and the stable, water-soluble nitroxide radical known as TEMPOL have been studied extensively with respect to applications in energy storage. Here we report formulations wherein high concentrations of both are achieved in a single solution and the reversible electrochemistry of each is retained. We demonstrate one of several potential applications by constructing a high optical density electrochromic device.

Проблемы локализации внутриглазного вколоченного инородного тела. Клинический случай

The article describes a clinical case of an eye injury with presence an intraocular foreign body (IFB), the localization of which was problematic. Patient T was 28 years old, was admitted with complaints of lack of vision, redness and lacrimation from the left eye. From the anamnesis – while working, he hit metal with a hammer, and the scale flew off into the left eye. In addition to the standard ophthalmologic examination, electrophysiological examination, B-scan and UBM were performed. According to the B-scan data, high optical density IFB was detected in the shells 9 mm from the upper border of the optic disc, in the 1-hour meridian, approximately 3.5 mm long. According to the X-ray data of the orbit in 2 projections, an X-ray contrast shadow, metal density, up to 3.0 mm in size was revealed. Radiography of Baltin–Comberg was not performed due to the lack of technical capability. During a standard three-port vitrectomy in the area of possible foreign body occurrence, the retina was damaged, there was a local detachment, but the foreign body itself was not visualized. In addition, during a thorough, detailed examination using a sclerocompressor, no visible defects of the sclera were found transvitreally. In the early postoperative period, the patient was performed with a computed tomogram, where the presence of a foreign body was confirmed, which was adjacent to the posterior wall of the eyeball for 1 hour with clear contours, measuring 3х3 mm. Taking into account the non-standard situation, the absence of a foreign body in the vitreous cavity, it was decided to re-search and remove the foreign body by using of the diascleral method. For a clearer contrast, diaphanoscopy was used, which made it possible to visualize and accurately localize a foreign body in the layers of the sclera. Conclusion. In the presence of IFB for search and precise localization, it is first of all necessary to perform the radiological Baltin-Comberg method. In cases when FB is not visualized intraoperatively, is impaled into the layers of the eye and the radiological Baltin-Comberg method has not been performed, diaphanoscopy of the eye is the optimal auxiliary method for searching for «hidden» foreign bodies. Key words: intraocular foreign body, radiological method of Baltin-Comberg, diaphanoscopy of the eye.

On the origin and correction for inner filter effects in fluorescence. Part II: secondary inner filter effect -the proper use of front-face configuration for highly absorbing and scattering samples

Fluorescence is an established technology for studying molecular processes and molecular interactions. More recently fluorescence became a leading method for detection, sensing, medical diagnostics, biotechnology, imaging, DNA analysis, and gene expression. Consequently, precise and accurate measurements in various conditions have become more critical for proper result interpretations. Previously, in Part 1, we discussed inner filter effect type I, which is a consequence of the instrumental geometrical sensitivity factor and absorption of the excitation. In this part, we analyze inner filter effect type II and discuss the practical consequences for fluorescence measurements in samples of high optical density (absorbance/scattering). We consider both the standard square and front-face experimental configurations, discuss experimental approaches to limit/mitigate the effect and discuss methods for correcting and interpreting experimental results.

The Use of Silica Microparticles to Improve the Efficiency of Optical Hyperthermia (OH).

Although optical hyperthermia could be a promising anticancer therapy, the need for high concentrations of light-absorbing metal nanoparticles and high-intensity lasers, or large exposure times, could discourage its use due to the toxicity that they could imply. In this article, we explore a possible role of silica microparticles that have high biocompatibility and that scatter light, when used in combination with conventional nanoparticles, to reduce those high concentrations of particles and/or those intense laser beams, in order to improve the biocompatibility of the overall procedure. Our underlying hypothesis is that the scattering of light caused by the microparticles would increase the optical density of the irradiated volume due to the production of multiple reflections of the incident light: the nanoparticles present in the same volume would absorb more energy from the laser than without the presence of silica particles, resulting either in higher heat production or in the need for less laser power or absorbing particles for the same required temperature rise. Testing this new optical hyperthermia procedure, based on the use of a mixture of silica and metallic particles, we have measured cell mortality in vitro experiments with murine glioma (CT-2A) and mouse osteoblastic (MC3T3-E1) cell lines. We have used gold nanorods (GNRs) that absorb light with a wavelength of 808 nm, which are conventional in optical hyperthermia, and silica microparticles spheres (hereinafter referred to as SMSs) with a diameter size to scatter the light of this wavelength. The obtained results confirm our initial hypothesis, because a high mortality rate is achieved with reduced concentrations of GNR. We found a difference in mortality between CT2A cancer cells and cells considered non-cancer MC3T3, maintaining the same conditions, which gives indications that this technique possibly improves the efficiency in the cell survival. This might be related with differences in the proliferation rate. Since the experiments were carried out in the 2D dimensions of the Petri dishes, due to sedimentation of the silica particles at the bottom, whilst light scattering is a 3D phenomenon, a large amount of the energy provided by the laser escapes outside the medium. Therefore, better results might be expected when applying this methodology in tissues, which are 3D structures, where the multiple reflections of light we believe will produce higher optical density in comparison to the conventional case of no using scattering particles. Accordingly, further studies deserve to be carried out in this line of work in order to improve the optical hyperthermia technique.

36‐4: Invited Paper: The Development of Blackened Backplane Technology for Optical Fingerprint Display

The display with blackened metal backplane presents superior decorative black appearance or high optical density (OD) light shielding integrated to optical fingerprinting senor. In this paper, we have fabricated two‐layer blackened metal wiring by high resolution patterning techniques with dry etching method and optimized the reflectivity of the novel blackened material. It has been utilized to an optical in‐cell fingerprint LCD to improve the reflectivity, which achieves 64% reflectivity reducing and lower than previous one. And it also has been employed for achieving narrowed line‐width high and high optical density demand for collimated layer in optical fingerprint sensor integrated to an OLED display.

High Carotenoid Mutants of Chlorella vulgaris Show Enhanced Biomass Yield under High Irradiance.

Microalgae represent a carbon-neutral source of bulk biomass, for extraction of high-value compounds and production of renewable fuels. Due to their high metabolic activity and reproduction rates, species of the genus Chlorella are highly productive when cultivated in photobioreactors. However, wild-type strains show biological limitations making algal bioproducts expensive compared to those extracted from other feedstocks. Such constraints include inhomogeneous light distribution due to high optical density of the culture, and photoinhibition of the surface-exposed cells. Thus, the domestication of algal strains for industry makes it increasingly important to select traits aimed at enhancing light-use efficiency while withstanding excess light stress. Carotenoids have a crucial role in protecting against photooxidative damage and, thus, represent a promising target for algal domestication. We applied chemical mutagenesis to Chlorella vulgaris and selected for enhanced tolerance to the carotenoid biosynthesis inhibitor norflurazon. The NFR (norflurazon-resistant) strains showed an increased carotenoid pool size and enhanced tolerance towards photooxidative stress. Growth under excess light revealed an improved carbon assimilation rate of NFR strains with respect to WT. We conclude that domestication of Chlorella vulgaris, by optimizing both carotenoid/chlorophyll ratio and resistance to photooxidative stress, boosted light-to-biomass conversion efficiency under high light conditions typical of photobioreactors. Comparison with strains previously reported for enhanced tolerance to singlet oxygen, reveals that ROS resistance in Chlorella is promoted by at least two independent mechanisms, only one of which is carotenoid-dependent.

Radial profile measurement with an improved 1 kHz Thomson scattering system on Versatile Experiment Spherical Torus.

A Thomson scattering (TS) system has been utilized to measure the electron temperature and density of the core region of Versatile Experiment Spherical Torus (VEST). Recently, the laser injection system is successfully upgraded adopting the burst laser with the repetition rate of 1 kHz and the energy of 2J. Furthermore, improved collection optics with additional polychromators and a 32-channel fast digitizer are prepared to observe the fast time evolution of radial profiles. This improvement is essential to study fast phenomena such as internal reconnection event (IRE). We increase the TS signal and reduce the stray light by introducing new filters having better optical properties such as high optical density at 1064nm, transmission, and reflectance. Moreover, the optimum reverse bias voltages are newly set to make the system operational independent of the background radiation. As a result, 1 kHz radial profiles of the core electron temperature and density are measured for the first time, showing characteristics of IREs in VEST.

The reduction of the thermal quenching effect in laser-excited phosphor converters using highly thermally conductive hBN particles

Phosphor converters for solid state lighting applications experience a strong thermal stress under high-excitation power densities. The recent interest in laser diode based lighting has made this issue even more severe. This research presents an effective approach to reduce the thermal quenching effect and damage of laser-excited phosphor-silicone converters using thermally conductive hexagonal boron nitride (hBN) particles. Herein, the samples are analyzed by employing phosphor thermometry based on the photoluminescence decay time, and thermo-imaging techniques. The study shows that hBN particle incorporation increases the thermal conductivity of a phosphor-silicone mixture up to 5 times. It turns out, that the addition of hBN to the Eu^{2+} doped chalcogenide-silicone converters can increase the top-limit excitation power density from 60 to 180 W cm^{-2}, thus reaching a 2.5 times higher output. Moreover, it is shown that the presence of hBN in Ce^{3+} activated garnet phosphor converters, may increase the output power by up to 1.8 times and that such converters can withstand 218 W cm^{-2} excitation. Besides, hBN particles are also found to enhance the stability of the converters chromaticity and luminous efficacy of radiation. This means that the addition of hBN particles into silicone-based phosphor converter media is applicable in a wide range of different areas, in particular, the ones requiring a high optical power output density.

A Flash‐Induced Robust Cu Electrode on Glass Substrates and Its Application for Thin‐Film μLEDs

A robust Cu conductor on a glass substrate for thin-film μLEDs using the flash-induced chemical/physical interlocking between Cu and glass is reported. During millisecond light irradiation, CuO nanoparticles (NPs) on the display substrate are transformed into a conductive Cu film by reduction and sintering. At the same time, intensive heating at the boundary of CuO NPs and glass chemically induces the formation of an ultrathin Cu2 O interlayer within the Cu/glass interface for strong adhesion. Cu nanointerlocking occurs by transient glass softening and interface fluctuation to increase the contact area. Owing to these flash-induced interfacial interactions, the flash-activated Cu electrode exhibits an adhesion energy of 10Jm-2 , which is five times higher than that of vacuum-deposited Cu. An AlGaInP thin-film vertical μLED (VLED) forms an electrical interconnection with the flash-induced Cu electrode via an ACF bonding process, resulting in a high optical power density of 41mWmm-2 . The Cu conductor enables reliable VLED operation regardless of harsh thermal stress and moisture infiltration under a high-temperature storage test, temperature humidity test, and thermal shock test. 50 × 50 VLED arrays transferred onto the flash-induced robust Cu electrode show high illumination yield and uniform distribution of forward voltage, peak wavelength, and device temperature.