Optical Profiles Research Articles

Pattern analysis of activated partial thromboplastin time clot waveform for detection of hemostatic changes in sepsis patients

Objectives: Coagulation is a dynamic process. Quantitative data on fibrin polymerization can be obtained by thoroughly analyzing the optical profile of the process of coagulation. This study aims to identify the changes in the activated partial thromboplastin time (APTT) clot waveform analysis (CWA) in sepsis. Materials and Methods: Blood samples of sepsis patients from the intensive care unit received for evaluation of APTT were taken for study. The samples were run in Automated Coagulation Analyzer Sysmex - coagulation system (CS) 2400, and APTT CWA was done. Statistical analysis: Statistical analysis was performed using IBM Statistical Package for the Social Sciences Statistics for Windows, version 20.0 NY. The clot waveform of APTT was analyzed in patients with sepsis. Sensitivity, specificity, positive, and negative predictive values of biphasic form in detecting disseminated intravascular coagulation (DIC) in sepsis patients were calculated. Results: A total of 133 blood samples were analyzed. Prolonged APTT was seen in 23% (n = 44). Among the patients with prolonged APTT, 79.5% (n = 35) cases had an altered CWA. In patients with altered CWA, 34% (n = 45) had sepsis with an abnormal wave pattern, and 11% (n = 15) had a biphasic waveform (BPW). DIC was diagnosed in 41% of cases (n = 55). The APTT CWA of sepsis patients with DIC revealed abnormal wave patterns in 31% (n = 17) and biphasic waveforms (BPW) in 18% (n = 10). The sensitivity, specificity, positive, and negative predictive values of the biphasic waveform in detecting DIC in sepsis patients were 18%, 93.5%, 66.6%, and 61.8%, respectively. Conclusions: The study demonstrated significant changes in the APTT CWA in sepsis. The presence of abnormal wave patterns in sepsis suggests liver dysfunction progressing to liver failure. A BPW in sepsis has a high specificity for DIC, which warrants immediate clinical intervention.

Evolution of the Sérsic index up to z = 2.5 from JWST and HST

Context. The Hubble Space Telescope (HST) has long been the only instrument able to allow us to investigate the structure of galaxies up to redshift z = 3, limited to the rest-frame UV and optical. The James Webb Space Telescope (JWST) is now unveiling the rest-frame near-IR structure of galaxies, less affected by dust attenuation and more representative of their underlying stellar mass profiles. Aims. We measure the evolution with redshift of the rest-frame optical and near-IR Sérsic index (n), and examine the dependence on stellar mass and star-formation activity across the redshift range 0.5 ≤ z ≤ 2.5. Methods. For an HST-selected parent sample in the CANDELS fields we infer rest-frame near-IR Sérsic profiles for ≈15 000 galaxies in publicly available NIRCam imaging mosaics from the COSMOS-Web and PRIMER surveys. We augment these with rest-frame optical Sérsic indices, previously measured from HST imaging mosaics. Results. The median Sérsic index evolves slowly or not at all with redshift, except for very high-mass galaxies (M⋆ > 1011 M⊙), which show an increase from n ≈ 2.5 to n ≈ 4 at z < 1. High-mass galaxies have higher n than lower-mass galaxies (the sample reaches down to M⋆ = 109.5 M⊙) at all redshifts, with a stronger dependence in the rest-frame near-IR than in the rest-frame optical at z > 1. This wavelength dependence is caused by star-forming galaxies that have lower optical than near-IR n at z > 1 (but not at z < 1). Both at optical and near-IR wavelengths, star-forming galaxies have lower n than quiescent galaxies, confirming and fortifying the result that across cosmic time a connection exists between star-formation activity and the radial stellar mass distribution. Besides these general trends that confirm previous results, two new trends emerge: (1) at z > 1 the median near-IR n varies strongly with star formation activity, but not with stellar mass, and (2) the scatter in near-IR n is substantially higher in the green valley (0.25 dex) than on the star-forming sequence and among quiescent galaxies (0.18 dex) – this trend is not seen in the optical because dust and young stars contribute to the variety in optical light profiles. Our newly measured rest-frame near-IR radial light profiles motivate future comparisons with radial stellar mass profiles of simulated galaxies as a stringent constraint on processes that govern galaxy formation.

Observations of Saharan Dust Intrusions over Potenza, Southern Italy, During 13 Years of Lidar Measurements: Seasonal Variability of Optical Properties and Radiative Impact

We present a multi-year study of Saharan dust intrusions on a mountainous site located in the central Mediterranean Basin regarding their aerosol optical and geometrical properties. The observations were carried out at the Consiglio Nazionale delle Ricerche-Istituto di Metodologie per l’Analisi Ambientale (CNR-IMAA) located in Potenza (40,360N, 15,440E), Italy, from March 2010 to October 2022, using ACTRIS (Aerosol Clouds and Trace Gases Research InfraStructure). A total of 101 night-time lidar measurements of dust intrusions were identified. The following properties were calculated for the periods December, January, February (DJF), March, April, May (MAM), June, July, August (JJA) and September, October, November (SON): aerosol layer center of mass altitude, particle lidar ratio at 355 and 532 nm, particle depolarization ratio at 532 nm and backscattering Ångström exponent at 532–1064 nm. Both geometrical and optical aerosol properties vary considerably with the seasons. During SON and DJF, air masses transporting dust travel at lower altitudes, and become contaminated with local continental particles. In MAM and JJA, dust is also likely to travel at higher altitudes and rarely mix with other aerosol types. As a result, aerosols are larger in size and irregular in shape during the warm months. The ratio of the lidar ratios at 355 and 532 nm is 1.11 ± 0.15 in DJF, 1.12 ± 0.07 in SON, 0.94 ± 0.12 in MAM, and 0.92 ± 0.08 in JJA. The seasonal radiative effect estimated using the Fu–Liou–Gu (FLG) radiative transfer model indicates the most significant impact during the JJA period. A negative dust radiative effect is observed both at the surface (SRF) and at the top of the atmosphere (TOA) in all the seasons, and this could be related to a minimal contribution from black carbon. Specifically, the SRF radiative effect estimation is −14.48 ± 1.32 W/m2 in DJF, −18.00 ± 0.89 W/m2 in MAM, −22.08 ± 1.36 W/m2 in JJA, and −13.47 ± 1.12 W/m2 in SON. Instead, radiative effect estimation at the TOA is −22.23 ± 2.06 W/m2 in DJF, −38.23 ± 2.16 W/m2 in MAM, −51.36 ± 3.53 W/m2 in JJA, and −22.57 ± 2.11 W/m2 in SON. The results highlight how the radiative effects of the particles depend on the complex relationship between the dust load, their altitude in the troposphere, and their optical properties. Accordingly, the knowledge of aerosols optical property profiles is of primary importance to understand the radiative impact of dust.

A genome-wide atlas of human cell morphology.

A key challenge of the modern genomics era is developing empirical data-driven representations of gene function. Here we present the first unbiased morphology-based genome-wide perturbation atlas in human cells, containing three genome-wide genotype-phenotype maps comprising CRISPR-Cas9-based knockouts of >20,000 genes in >30 million cells. Our optical pooled cell profiling platform (PERISCOPE) combines a destainable high-dimensional phenotyping panel (based on Cell Painting) with optical sequencing of molecular barcodes and a scalable open-source analysis pipeline to facilitate massively parallel screening of pooled perturbation libraries. This perturbation atlas comprises high-dimensional phenotypic profiles of individual cells with sufficient resolution to cluster thousands of human genes, reconstruct known pathways and protein-protein interaction networks, interrogate subcellular processes and identify culture media-specific responses. Using this atlas, we identify the poorly characterized disease-associated TMEM251/LYSET as a Golgi-resident transmembrane protein essential for mannose-6-phosphate-dependent trafficking of lysosomal enzymes. In sum, this perturbation atlas and screening platform represents a rich and accessible resource for connecting genes to cellular functions at scale.

Near-Infrared Magnetic Circularly Polarized Luminescence and Slow Magnetic Relaxation in a Tetrazinyl-Bridged Erbium Metallocene.

The magnetic and magneto-optical properties of a tetrazinyl radical-bridged ErIII metallocene, [(Cp*2ErIII)2(bpytz•-)][BPh4] (1; Cp* = pentamethylcyclopentadienyl, bpytz = 3,6-bis(3,5-dimethyl-pyrazolyl)-1,2,4,5-tetrazine), are reported. As confirmed by these studies strong Ln-rad coupling is achieved, with 1 exhibiting slow magnetic relaxation under a 1000 Oe dc field. The optical and magneto-optical profile of 1 is completed by both near-infrared (NIR) luminescence and magnetic circularly polarized luminescence (MCPL), representing the first example of NIR MCPL with ErIII.

Label-free imaging flow cytometry for cell classification based directly on multiple off-axis holographic projections.

Imaging flow cytometry allows highly informative multi-point cell analysis for biological assays and medical diagnosis. Rapid processing of the imaged cells during flow allows real-time classification and sorting of the cells. Off-axis holography enables imaging flow cytometry without chemical cell staining but requires digital processing to the optical path delay profile for each frame before the cells can be classified, which slows down the overall processing throughput. We present a method for real-time cell classification via label-free quantitative imaging flow cytometry using digital holography, offering a comprehensive representation of cellular structures, without the need for digital processing before automatic cell classification. We aim to develop an automatic cell classification scheme based directly on the off-axis holographic projections of the cells during flow and test it for stain-free imaging flow cytometry of white blood cells. After building a dedicated off-axis holographic microscopy system for acquiring white blood cells during flow, we apply deep-learning classification directly in the off-axis hologram space, rather than in the quantitative phase profile space. This way, we simplify computational processes and allow a significant increase in the cell classification throughput. In addition, by utilizing multiple-viewpoint holographic projections of the cells rotated during flow, instead of using a single projection, we obtain better classification results due to the additional cellular information gained. Our technique demonstrates increasing accuracy with additional viewpoint holographic projections from the optical system, achieving a 7.69% improvement when processing ten interferometric projections compared with a single interferometric projection (regular off-axis hologram). Our technique also outperforms using multiple optical path delay profile projections, requiring off-axis holographic digital preprocessing, by 17.95%, because the holographic projections are analyzed directly without preprocessing and includes the amplitude information as well. Our cell classification approach has great potential for high-throughput, high-content, label-free imaging flow cytometry for classification of large-scale cellular datasets and real-time cell classification during flow in clinical settings.

Modelling and Classification of Optical Beam Profiles Using Vision Transformer

Modelling and Classification of Optical Beam Profiles Using Vision Transformer

Electrodeposition of Al coating onto a 300M steel from AlCl3/acetamide deep eutectic solvents for corrosion protection

Aluminum coating was expected to be used for corrosion protection of 300M steel. Al coating was prepared using the galvanostatic electrodeposition from AlCl3/acetamide (1.3:1) system for the corrosion protection of 300M steel. This process was conducted at varying current density (2–8 mA·cm−2) and electrodeposition time (1 and 2 h). The chronopotentiometry revealed that the size of Al nucleus was proportional to the inverse of overpotential. Thus, the morphology of Al coating was characterized by scanning electron microscope and optical surface profiler. The results indicated a decrease in Al grain sizes and the roughness fluctuation with increasing current density. Moreover, the corrosion resistance of Al coatings was evaluated in a 3.5 wt% NaCl solution using the potentiodynamic polarization and electrochemical impedance spectroscopy test. It was illustrated that corrosion current density decreased by 57.8 % at 6 mA·cm−2 with the electrodeposition time increasing from 1 to 2 h, while the value decreased by 75.9 % with the current density raising from 5 to 6 mA·cm−2 for 2 h. Al coating electrodeposited at 6 mA cm−2 for 2 h represented the highest corrosion resistance with the charge transfer resistance of 5695 Ω·cm2, while the value of 300M steel was 914 Ω·cm2. Finally, X-ray diffraction pattern suggested that corroded coatings compositions included Al2O3, AlO(OH) and AlCl3·6H2O. The study was considered to provide a promising method using AlCl3/acetamide to electrodeposit Al coatings for protecting 300M steel from corrosion.

Picometre-level surface control of a closed-loop, adaptive X-ray mirror with integrated real-time interferometric feedback.

We provide a technical description and experimental results of the practical development and offline testing of an innovative, closed-loop, adaptive mirror system capable of making rapid, precise and ultra-stable changes in the size and shape of reflected X-ray beams generated at synchrotron light and free-electron laser facilities. The optical surface of a piezoelectric bimorph deformable mirror is continuously monitored at 20 kHz by an array of interferometric sensors. This matrix of height data is autonomously converted into voltage commands that are sent at 1 Hz to the piezo actuators to modify the shape of the mirror optical surface. Hence, users can rapidly switch in closed-loop between pre-calibrated X-ray wavefronts by selecting the corresponding freeform optical profile. This closed-loop monitoring is shown to repeatably bend and stabilize the low- and mid-spatial frequency components of the mirror surface to any given profile with an error <200 pm peak-to-valley, regardless of the recent history of bending and hysteresis. Without closed-loop stabilization after bending, the mirror height profile is shown to drift by hundreds of nanometres, which will slowly distort the X-ray wavefront. The metrology frame that holds the interferometric sensors is designed to be largely insensitive to temperature changes, providing an ultra-stable reference datum to enhance repeatability. We demonstrate an unprecedented level of fast and precise optical control in the X-ray domain: the profile of a macroscopic X-ray mirror of over 0.5 m in length was freely adjusted and stabilized to atomic level height resolution. Aside from demonstrating the extreme sensitivity of the interferometer sensors, this study also highlights the voltage repeatability and stability of the programmable high-voltage power supply, the accuracy of the correction-calculation algorithms and the almost instantaneous response of the bimorph mirror to command voltage pulses. Finally, we demonstrate the robustness of the system by showing that the bimorph mirror's optical surface was not damaged by more than 1 million voltage cycles, including no occurrence of the `junction effect' or weakening of piezoelectric actuator strength. Hence, this hardware combination provides a real time, hyper-precise, temperature-insensitive, closed-loop system which could benefit many optical communities, including EUV lithography, who require sub-nanometre bending control of the mirror form.

Lubrication-Enhanced Mechanisms of Bentonite Grease Using 2D MoS2 with Narrow Lateral Size and Thickness Distributions

2D MoS2 with narrow lateral size and thickness distributions was introduced to promote the anti-friction and anti-wear properties of the bentonite grease (BG) in a state of boundary lubrication. Optical microscopy (OM), and 3D optical profilers (3D OP), Raman spectrometry (Raman), scanning electron microscope, energy dispersion spectrum (SEM-EDS), and X-ray photoelectron spectroscopy (XPS) were applied to characterize the wear surface of the GCr15 bearing steel/GCr15 bearing steel contact. It is found that the average friction coefficient (AFC), wear scar diameter (WSD), surface roughness and average wear scar depth of BG + 1.2 wt.% 2D MoS2 were effectively reduced by approximately 22.15%, 23.14%, 55.15%, and 21.1%, respectilvely, compared with BG under the working condition of 392N, 75 °C, 1 h, and 1200 rpm. Raman, EDS and XPS results jointly demonstrated that a stable adsorbed film and a robust tribochemical film composed of Fe2O3, FeSO4, Fe2(SO4)3, FeSO3, FeS, FeO and MoO3, which further contributes to the enhancement of lubrication performance.

Filtering-free complex-valued DSB-16QAM generation for a 100 G direct detection optical interconnection.

In this Letter, a complex-valued double-sideband 16QAM (CV-DSB-16QAM) signaling scheme is proposed and experimentally demonstrated in a 100-Gb/s intensity modulation/direct detection (IM/DD) interconnection system. Unlike the conventional real-valued double-sideband (DSB) quadrature amplitude modulation (QAM) of relatively lower spectral efficiency (SE) and single-sideband (SSB) QAM relying on sharp-edged optical filtering, the CV-DSB-16QAM signal is generated by combining two independent sideband modulated QPSK signals using a single intensity modulator with an optical filtering-free profile, which also saves one photodiode and one analog-to-digital-converter compared with the twin-SSB scheme. Compared to typical pulse amplitude modulation or SSB schemes, the proposed approach offers a compelling alternative for complex-valued DD systems' evolution, particularly in scenarios with high SE demands and controllable chromatic dispersion. The experimental demonstration evaluates a 25-GBaud CV-DSB-16QAM signal over a 2-km standard single-mode fiber (SSMF), achieving a net bit rate of 100 Gb/s and occupying only a 25.1-GHz electrical bandwidth with a 4% guard band.

Enhancement in the dynamic range of an astigmatic defocus sensor through intensity measurement at two out-of-focus planes

Abstract The astigmatic defocus sensor is effective for measuring low strength of defocus in the optical beam phase profile. But, the sensor fails in the presence of higher strength of defocus in the optical beam, i.e. its dynamic range is low. The paper propose a modified version of the conventional astigmatic defocus sensor capable of providing enhance dynamic range compared to that of a conventional sensor. The proposed sensor requires the intensity measurement at two out-of-focus plane. A comparative study in terms of dynamic range is carried out and simulation results showing enhance dynamic range are provided to validate the proposed technique.

Evaluation of the Biological Effect of a Nicotinamide-Containing Broad-Spectrum Sunscreen on Photodamaged Skin.

UVA-UVB increases skin matrix metalloproteinases and breaks down extracellular proteins and fibrillar type1 collagen, leading to photodamage. Topical application of nicotinamide prevents UV-induced immunosuppression. Several studies have demonstrated the importance of protection against UV. This study aims to determine the biological effect of a high broad-spectrum UVB-UVA sunscreen containing nicotinamide and panthenol (SSNP) on photodamaged skin using linear confocal optical coherence tomography (LC-OCT), immunohistochemistry, and RNA profiling. Two areas of severely photodamaged forearm skin (L01 and L02) and one less sun-damaged (naturally protected) area on the inner part of the forearm (L03) were identified in 14 subjects. These areas were imaged using LC-OCT and L01 and L03 were biopsied at baseline. After 4weeks of treatment with SSNP, L02 was reimaged using LC-OCT, and biopsied. Histology, immunostaining with p21, p53, PCNA, and CPD, and RNA sequencing were performed in all samples. LC-OCT analysis showed that epidermis thickness and the number of keratinocytes is higher in the sun-exposed areas than in the non-exposed areas. Comparing before and after treatment, even though there is a trend towards normalization, the differences were not statistically significant. The expression of p21, PCNA, p53, and CPD increased in severely photodamaged skin compared to less-damaged skin. When comparing before and after treatment, only p21 showed a trend to decrease expression. RNA sequencing analysis identified 1552 significant genes correlating with the progression from non-visibly photodamaged skin to post-treatment and pre-treatment samples; in the analysis comparing pre- and post-treatment samples, 5429 genes were found to be significantly associated. A total of 1115 genes are common in these two analyses. Additionally, nine significant genes from the first analysis and eight from the second are related to collagen. Six of these collagen genes are common in the two analyses. MAPK and cGMP-PKG signalling pathways are upregulated in the progression to photodamage analysis. In the pre- and post-treatment analysis, 32 pathways are downregulated after treatment, the most statistically significant being the ErbB, Hippo, NOD-like receptor, TNF, and NF-kB signalling pathways. This study demonstrates the role of SSNP in collagen generation, highlights the relevance of the cGMP-PKG and MAPK signalling pathways in photodamage, and shows the ability of SSNP to downregulate pathways activated by UV exposure. Additionally, it deepens our understanding of the effect of SSNP on immune-related pathways.

Step-controlled ultra-precise chemical etching for removing chemical residues from metallic niobium surfaces

This work presents a highly precise chemical etching process designed to achieve controlled modulation of the formation and removal of the oxide layer on the surface of niobium (Nb). Angle-resolved X-ray photoelectron spectroscopy (ARXPS) results indicate that the surface attains a saturated oxide layer thickness above 3 nm following treatment with HNO3. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) results show that the removal efficiency of chemical residue on the Nb surface significantly improves with increased treatment time in HNO3 and HF. A detailed surface analysis with a 3D optical profiler demonstrates that this method enables uniform etching without compromising the surface flatness of Nb while effectively removing the chemical residues. Electrochemical stability measurements and Vickers hardness tests reveal that cyclic etching exerts minimal impact on the mechanical properties of Nb, while the self-healing characteristics of the surface oxide layer maintain its chemical stability. This method not only advances precision etching for Nb but also opens up the potential for its application in high-performance materials where surface integrity and chemical resilience are paramount.

Abstract 4113951: Calcification Alters Luminal Surface Complexity in Cadaveric Left Anterior Descending Arteries

Background: Understanding the intricacies of luminal surface topographic changes in pathologic coronary arteries may yield insight not only on the efficacy of existing clinical interventions (e.g. impact of surface changes on stent anchoring), but also on the subsequent hemodynamic changes and pathophysiology of thrombus formation. In this study, we aim to detect and quantify luminal surface alterations induced by the presence of calcification in cadaveric left anterior descending arteries (LADs) using a novel approach–surface metrology. Methods: LADs (n=10) were harvested from cadaveric hearts using a systematic dissection approach, scanned using the Bruker Skyscan 1173 microCT scanner, and then underwent threshold-based image segmentation on Dragonfly by Object Research Systems to quantify the total calcium volume present throughout the vessel. Each specimen was then splayed open and up to 15 scans were performed at 20X magnification using the Sensofar S Neox optical profiler. Each scan subsequently underwent surface metrologic scale-sensitive fractal analyses in SensoMap 10. Results: Extent of calcification was standardized and expressed using the following ratio: total calcium volume by total vessel length (TC/VL). We considered a TC/VL ratio of 0-0.25 as low calcification and 0.26-0.5 as high calcification. Interestingly, our findings demonstrated statistically significant increases in smooth-rough crossover (SRC) and scale of maximum complexity (Smfc) with positive correlation, but reductions in fractal complexity (Lsfc) and fractal dimension (Dls) with negative correlation, in highly calcified compared to lowly calcified LADs. Conclusions: Our data suggests that the presence of calcium in the walls of LADs may translate to increased roughness in luminal surfaces generally, but smoothness over calcified plaques, locally. Our proposed mechanism is increased endothelial tension directly over areas of calcification, thus reducing surface complexity. Future studies will involve modeling blood flow using smooth particle hemodynamics (SPH) based on complete luminal and surface topographical geometries to evaluate the impact of these surface changes on hemodynamics.

Morphological and Optical Profiling of Melanocytes and SK-MEL-28 Melanoma Cells Via Digital Holographic Microscopy and Quantitative Phase Imaging.

Melanoma, which originates from pigment-producing melanocytes, is an aggressive and deadly skin cancer. Despite extensive research, its mechanisms of progression and metastasis remain unclear. This study uses quantitative phase imaging via digital holographic microscopy, Principal Component Analysis (PCA), and t-distributed Stochastic Neighbor Embedding (t-SNE) to identify the morphological, optical, and behavioral differences between normal melanocytes and SK-MEL-28 melanoma cells. Our findings reveal significant differences in cell shape, size, and internal organization, with SK-MEL-28 cells displaying greater size variability, more polygonal shapes, and higher optical thickness. Phase shift parameters and surface roughness analyses underscore melanoma cells' uniform and predictable textures. Violin plots highlight the dynamic and varied migration of SK-MEL-28 cells, contrasting with the localized movement of melanocytes. Hierarchical clustering of correlation matrices provides further insights into complex morphological and optical relationships. Integrating label-free imaging with robust analytical methods enhances understanding of melanoma's aggressive behavior, supporting targeted therapies and highlighting potential biomarkers for precise melanoma diagnostics and treatment.

Optoelectronic properties of novel layered materials under encapsulation: 2D Copper Iodide and Silver Iodide

Many novel freestanding two-dimensional materials can be stabilized when placed over a proper substrate or put under encapsulation. Among the different possibilities, graphene and h-BN are commonly used due to their availability and compatibility. In that scenario, it is important to understand how the possible interactions between the core and substrate/encapsulating layers as well as the lattice mismatch affect the optoelectronic properties of the core material. In this work, we use ab initio calculations to study the structural and optolectronic properties of the recently synthesized 2D CuI and AgI layers, which are stabilized under graphene encapsulation (Mustonen et al. (2022)). In addition, the possibility of h-BN encapsulation is also explored. We find that the optoelectronic properties of the core materials are greatly preserved under encapsulation—especially under h-BN. Their bandgaps suffer small variations that mainly originate from the internal strain that results from supercell relaxation. We also see a rehybridization of the electronic bands from the core material whenever they cross or lie close to bands from the encapsulating layers, as expected. This effect is particularly strong for graphene encapsulation. The optical absorption profiles show a combination of features coming from the spectra of the isolated layers with minor modifications introduced by these effects. In particular, a strong and broad absorption is seen in the UV range when using h-BN. Finally, we study a possible CuI-AgI heterobilayer, both isolated and under encapsulation. Interestingly, the structure presents a type-II band alignment that is well preserved under encapsulation, with potential applications in novel photovoltaic devices.

Optical properties of CVD-grown multilayer graphene on nickel using spectroscopic ellipsometry

Incorporating graphene into relevant technologies requires its integration with commercially suitable substrates. Understanding the interactions between graphene and these substrates is crucial, as graphene serves as an ideal model system for investigating electronic phenomena. In this work, we report the optical properties of multilayer graphene on nickel substrates using spectroscopic ellipsometry. We provide information on the spectral dependence of optical properties of multilayer graphene, such as the complex dielectric constant, refractive index, and optical conductivity in the energy range of 1.6–5.0 eV. The optical conductivity profile obtained from SE analysis showed a symmetrical peak at 4.38 eV, suggesting an interband transition from the π to π∗ orbital at the M point. The graphene/Ni interaction generated changes in the number of available states below the Fermi level, leading to significant changes in electron density. Our result provides the information essential for understanding relevant research and developing graphene-based optoelectronic applications.

Evolution of interface and surface morphology of WC/SiC multilayers with increase in number of bilayers

WC/SiC multilayer mirrors are promising elements for operation in the short wavelength range of hard X-rays and even gamma-rays. A set of WC/SiC multilayers with nominal bilayer thickness of 3.0 nm with 30, 50, 100, and 200 bilayers have been deposited by magnetron sputtering method. The evolution of interface and surface morphology with addition of the number of bilayers has been investigated. The methods of grazing incidence X-ray reflectivity, X-ray diffuse scattering, optical profiler, atomic force microscope, transmission electron microscopy and energy-dispersive X-ray spectroscopy have been used. It is found that the interface roughness plays a dominant role in interface imperfections of WC/SiC and it exhibits slight accumulation across the multilayers with the number of bilayers increasing. The surface roughness also increases in relatively high spatial frequency range as the number of bilayers has been added, due to the cumulative increase in interface roughness. The interface roughness accumulation ultimately contributes to the diminishment of optical performance of WC/SiC multilayers with a large number of bilayers. At the wavelength of 0.154 nm, a peak reflectivity of 69.2 % is achieved for a 100 bi-layer multilayer under the grazing incidence of approximately 1.5°, while lower reflectivity of 67.2 % for a 200 bi-layer multilayer.

Multivalent supramolecular fluorescent probes for accurate disease imaging.

Optical imaging is a powerful tool for early disease detection and effective treatment planning, but its accuracy is often compromised by the uptake of imaging materials by the mononuclear phagocyte system (MPS). Herein, we leverage multivalent host-guest interactions between cyanine dyes and β-cyclodextrin polymers to develop supramolecular probes with enhanced stability, optical, and transport profiles for accurate in vivo imaging. These multivalent interactions not only ensure the stability of the probes but also enhance fluorescence efficiency by minimizing nonradiative decay. Our self-assembly approach effectively modulates probe size and surface properties, enabling evasion of MPS clearance and promoting prolonged bloodstream circulation, thereby improving the signal-to-background ratio for imaging. The effectiveness of our design is demonstrated by substantial advancements in the early diagnosis of acute kidney injury and by providing high-contrast imaging and precise surgical navigation across various tumor models. Our strategy not only advances optical imaging materials toward clinical translation but also establishes a versatile platform applicable to multiple imaging modalities.