Polarized Light Microscopy Research Articles

Topographic Evaluation of the Remineralizing Potential of Biomimetic Scaffolds on Enamel White Spot Lesions: An InVitro Study.

The modern approach to managing noncavitated white spot lesions (WSLs) emphasizes noninvasive strategies and biomimetic remineralization. Biomimetic scaffolds are designed to regenerate dental tissues rather than simply repair them. This study aimed to assess lesion depth, enamel structure, and the elemental composition of artificially induced WSLs after treatment with biomimetic remineralization techniques. Ninety-six freshly extracted anterior teeth, free from caries or enamel defects and extracted due to periodontal disease, were used. White spot lesions were induced on the labial surfaces, and the samples were divided into three groups based on the remineralizing agent: Group I, treated with casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), which served as the positive control; Group II, treated with self-assembling peptide P11-4 (SAP-P11-4); and Group III, treated with phosphorylated nano-chitosan (Pchi-ACP). Enamel topography was analyzed at baseline and after treatment using polarized light microscopy, micro-Raman spectroscopy, and scanning electron microscopy. Statistical analysis was conducted using one-way ANOVA, Kruskal-Wallis, and Dunn's post hoc test (p = 0.05). The Kruskal-Wallis test indicated a significant difference in remineralization potential among the groups. Pchi-ACP showed the greatest reduction in lesion depth (62.65%), demonstrating significant subsurface enamel remineralization. This group also exhibited a smooth, regular enamel surface with shallow linear depressions. Elemental analysis confirmed successful calcium phosphate precipitation in Pchi-ACP, indicating a trend toward enamel regeneration. Pchi-ACP represents a promising biomimetic and minimally invasive approach for treating early WSLs, signifying a transition toward regenerative dentistry. (SAP-P11-4), while effective, was less successful than phosphorylated nano-chitosan but outperformed (CPP-ACP). Pchi-ACP demonstrates significant potential for minimally invasive treatment of early noncavitated carious lesions. By preserving natural tooth structure, this approach could greatly enhance oral health outcomes in the long term.

Label-Free Liquid Crystal Aptamer Sensors Based on Single-Stranded Nucleic Acid π-Structures for Detecting cTnI.

Cardiac troponin I (cTnI) is a highly sensitive and important serological marker for clinical diagnosis of myocardial injury. Its rapid detection is crucial for the early diagnosis of cardiovascular diseases such as acute myocardial infarction. In this study, based on nucleic acid molecular hybridization and aptamer-specific binding to target molecules, a label-free liquid crystal aptamer sensor based on single-stranded nucleic acid π-structures was developed and applied for the quantitative detection of cTnI. The CP1 and CP2 oligonucleotide chains, complementary to the bases at both ends of the aptamer, are covalently bonded to the sensor substrate via APTES and GA-mediated molecules. The aptamer forms a π-structure with CP1 and CP2 through nucleic acid hybridization, serving as a target molecule capture probe. When cTnI is present in the system, cTnI and the complementary oligonucleotide chains competitively bind with the aptamer, causing the breakdown of the π-structure within the sensor. This reinstates the long-range ordered alignment of the 5CB liquid crystal molecules within the sensor, enabling quantitative measurement of cTnI through variations in optical images. Experimental results show that within the range of 0.01 to 25 ng/mL for cTnI concentration, there is a linear correlation between the brightness area coverage (Br) in the polarized light microscopy images of the sensor and the logarithm of the cTnI concentration, with a correlation coefficient (r). The detection limit is 5.16 pg/mL. This method is label-free, simple to operate, and low-cost, with good specificity and a low detection limit, achieving cTnI detection in serum samples.

Polarised light scanner for digital pathology.

Digital pathology is rapidly transforming diagnostic pathology by allowing remote work and integration of artificial intelligence solutions. Nevertheless, certain technical issues remain to be resolved. Notably, digital images captured by conventional scanners cannot be subjected to polarised light analysis [1]. We have therefore studied if images obtained using the Glissando POL Brightfield and Polarised Light Scanner are comparable to those obtained using conventional polarised light microscopy. Hematoxylin and eosin stained sections from 75 cases, including cases of amyloidosis, periprosthetic membranes, foreign body granulomas, gout, pseudogout, and breast tissues with calcium oxalate crystals were examined using both, a polarised light microscope and the Glissando POL scanner. Representative digital images were acquired for comparison. We here show that in all settings, the images obtained by conventional polarised light microscopy and using the Glissando POL scanner were comparable. We conclude that the Glissando POL scanner can be safely integrated into a digital pathology workflow.

Enhancing geothermal petrography with convolutional neural networks

The qualitative assessment of a geothermal reservoir using petrography is often conducted during drilling to assess the permeability, porosity, and mineral geothermometry of the reservoir rocks especially when little is known about the subsurface during the exploration stage. The petrographic analysis includes visually estimating pore and vein fractions, identifying rock textures, describing the degree of alteration, recognizing the hydrothermal alteration minerals and indicated temperature, and noting the presence of shearing and various porosity types. This traditional method of visual estimation and assessment is prone to errors when averaging fields of view and can be labor-intensive, especially during time-sensitive drilling operations when a geologist must analyze hundreds of thin sections per well under a polarizing light microscope. In this study, indicated porosity levels were assigned to 103 geothermal core thin sections based on the grouping of the rock parameters as observed under a polarizing light microscope. To enhance the traditional visual assessment in petrography, this study trained and validated convolutional neural networks (CNNs) in the automatic rating of porosity based on these parameters and in the detection of epidote, a key production marker in high-temperature magmatic-intrusive geothermal systems. Photomicrographs of the geothermal well core thin sections were utilized as input data for training and validating the ResNet, AlexNet, and VGGNet architectures. The three CNN architectures achieved porosity classification precision ranging from 0.74 to 0.84, and epidote detection precision between 0.90 and 1.0 in plane-polarized light (PPL) photomicrographs. The results demonstrate that CNNs can significantly augment traditional petrography in evaluating geothermal well samples.

Spontaneous nanosized liposome formation from crude dried lecithin upon addition of glycerol

Nanosized liposomal vesicles (NLV) were successfully prepared using natural sunflower lecithin without the use of high-pressure homogenization or filtration. Upon glycerol addition to dispersions of lecithin multilamellar vesicles (MLVs), these broke down spontaneously to liposomes with diameters in the range of 100–200 nm. Static light scattering demonstrated that glycerol addition above 30% (w/w) induced the complete transformation of MLVs into NLVs. Langmuir trough compression experiments showed a two-region compressional behavior. Upon 62% (w/w) glycerol addition, the compressional modulus of the liposomes decreased from 18.5 to 8.13 mN/m. Water activity and pulse NMR measurements also showed a divergence in behavior above 30% (w/w) glycerol. Liposomes were not birefringent in water but became strongly birefringent at and above 30% (w/w) glycerol, as determined by polarized light microscopy, and lost all birefringence above 80% (w/w). This was interpreted as the induction of stress-birefringence in the phospholipid bilayers above 30% (w/w) glycerol, and a relaxation of such stress above 80% (w/w) glycerol. We hypothesize that the mixture of phospholipids in the lecithin results in an effective non-zero intrinsic curvature for the molecular mixture, which lowers the bending energy of the bilayer, allowing for an easier break-up upon mixing. Secondly, glycerol addition decreases attractive van der Waals’ interaction between lamellae in an MLV, thus weakening the multilamellar liposome walls. Glycerol also affects bilayer stability by strengthening the hydrogen bond network of water, which will affect phospholipid headgroup hydration. All these factors result in the spontaneous breakdown of MLVs into NLVs.

2,3-per-acylated α and β cyclodextrins as inducers of helical liquid crystalline phases

ABSTRACT For the first time, a comprehensive study of the mesomorphic, physical and orientation properties of helical mesophases induced by partially acylated cyclodextrins was carried out. Using polarisation microscopy, the formation of a helical mesophase was established when a nematic mixture of polar 4-alkoxy-4’-cyanobiphenyls (CB-2) was doped with chiral 2,3-per-acetylated and 2,3-per-propionylated α- and β-cyclodextrins. The clearance temperatures and helical pitch were measured. The high efficiency of helix twisting under the influence of these dopants and an increase in the orientational order parameter of the liquid crystal matrix were ascertained. Using Haller’s extrapolation method for approximation the temperature dependences of birefringence a decrease in inverse helix pitch (1/p) upon heating was shown to be due to a reduction in the LC order parameter. Quantum chemical simulation of the acetylated α- and β-cyclodextrins structure and their solvates with 4-pentyloxy-4’-cyanobiphenyl was performed, and their interaction energies and dipole moments were calculated. The formation of inclusion compounds of LC molecules into the internal cavity of acylated CDs was established. The higher interaction energy and helical twisting power, as well as the least destabilisation of the mesophase were shown to be observed for β-cyclodextrin derivatives.

Detection of Adulteration in Besan (Cicer Arietinum) Using Microscopic Technique

Detection of food adulteration in an unambiguous way requires a methodology that provides distinct differentiators between the authentic and adulterated samples. We present a simple method to detect the adulteration of Besan (chickpea flour), an extensively used food ingredient for different food products in the Indian culinary industry. As many as 10 different samples, both branded and non-branded samples, were procured from the market and were evaluated for their purity. Polarized light Microscope was used as a simple evaluation tool to assess the purity of the sample. The quality of the image in light, polarized light, polarized light with analyzer, and dark mode bring about a clear distinction between pure besan and adulterated sample. Sample analyses were done in 50 X to 1000 X magnification. This non-destructive analysis of the sample brings about even a very small degree of adulteration in the sample. From the analysis, it was clear that out of 10 samples tested, 5 samples were seen as adulterated. The chief adulterants were yellow pea flour and corn flour. This simple method provides easy detection of adulterants and adulteration in food samples.

Harnessing the past: Vibration analysis of organic additives in ancient plasters for sustainable building solutions

This study investigates plant-based organic additives and grains used in ancient earthen plasters from the caves of Karla, Bhaja, Pitalkhora, Ellora, and Aurangabad in Maharashtra, India, highlighting their relevance for sustainable modern construction. Stereo microscopy, FTIR spectrophotometry, and phytochemical analysis identified rice husk, millet, wheat, Chenopodium album, Paspalum, barnyard millet, foxtail millet, and Fumaria seeds as key organic components. Starch grain analysis confirmed the presence of wheat, millet, and mung bean starches, while polarized light microscopy revealed distinctive birefringence patterns, such as the Maltese cross. FTIR analysis of solvent extractions identified natural compounds, including starches, gums, proteins, oils, waxes, and tree resins. These organic additives, especially rice husk, prevalent in Karla, Bhaja, and Pitalkhora samples, and the balanced composition of hemp fibers, seeds, and gums in Ellora samples, contributed significantly to the strength and durability of the plasters. The use of beeswax and tree resins as natural binders further underscores the ingenuity of these ancient techniques. This research not only highlights the botanical diversity in ancient construction but also draws critical connections to modern sustainable practices. The carbon-negative potential of these materials, combined with their renewability and resilience, aligns closely with contemporary green building strategies, offering inspiration for eco-friendly construction rooted in traditional Indian architecture.

Low-dose tamoxifen treatment reduces collagen organisation indicative of tissue stiffness in the normal breast: results from the KARISMA randomised controlled trial.

Tissue stiffness, dictated by organisation of interstitial fibrillar collagens, increases breast cancer risk and contributes to cancer progression. Tamoxifen is a standard treatment for receptor-positive breast cancer and is also aproved for primary prevention. We investigated the effect of tamoxifen and its main metabolites on the breast tissue collagen organisation as a proxy for stiffness and explored the relationship between mammographic density (MD) and collagen organisation. This sub-study of the double-blinded dose-determination trial, KARISMA, included 83 healthy women randomised to 6months of 20, 10, 5, 2.5, and 1mg of tamoxifen or placebo. Ultrasound-guided core-needle breast biopsies collected before and after treatment were evaluated for collagen organisation by polarised light microscopy. Tamoxifen reduced the amount of organised collagen and overall organisation, reflected by a shift from heavily crosslinked thick fibres to thinner, less crosslinked fibres. Collagen remodelling correlated with plasma concentrations of tamoxifen metabolites. MD change was not associated with changes in amount of organised collagen but was correlated with less crosslinking in premenopausal women. In this study of healthy women, tamoxifen decreased the overall organisation of fibrillar collagens, and consequently, the breast tissue stiffness. These stromal alterations may play a role in the well-established preventive and therapeutic effects of tamoxifen. Trial registration ClinicalTrials.gov ID: NCT03346200. Registered November 1st, 2017. Retrospectively registered.

Single-shot 3 × 3 Mueller matrix microscopy with color polarization encoding.

Snapshot retrieval of linear Stokes parameters in polarized light microscopy has benefited from recent advances in nanotechnology which have made polarization image sensors commercially available. However, real-time retrieval of the 3 × 3 Mueller matrix (MM) is limited by the need for time-sequential change in polarization states in the input. In the present Letter, we propose a cost-effective technique for the real-time retrieval of the 3 × 3 Mueller matrix by encoding linear polarization states in each of the three color channels of the source and analyzing light passing through the sample using a color polarization sensor placed in the imaging plane of a transmission microscope. Validation experiments for samples under real-time imaging conditions are presented. To the best of our knowledge, this is the first report on the snapshot 3 × 3 Mueller matrix element retrieval in polarized light microscopy by combining division of focal plane (DoFP) color polarimetric sensing and polarization color encoding of the source.

A continuous plane of polarization rotator and detector based on the liquid crystal Θ-cell

Modulation of the polarization state of optical beams is crucial in advanced optical applications such as polarization microscopy, polarization rotation, and medical imaging. We demonstrate a continuous polarization rotator (PR) by utilizing the liquid crystals (LC) in Θ-cell configuration comprising of circular and parallel alignment of LC on two aligning glass substrates. A rotation of plane of polarization (PoP) up to ∼ 160˚ is observed using Stokes polarimetry. This is further substantiated by the mathematical analysis using Mueller matrix formalism. Further, the device is demonstrated as a PoP detector with high precision detection angle. The PoP is analyzed through single-shot imaging of the intensity distribution of transmitted light through the LC Θ-cell.

Rare Earth Elements enrichment in Triassic coals deposits and associated argillaceous rocks in Lesotho

The demand for rare earth elements has increased around the world due to their application in a variety of technological advancements. Previous studies have evaluated the potential of the rare earth elements and yttrium (REY) hosted within the Permian coal deposits of the main Karoo Basin (MKB) in Southern Africa. However, not a lot of scientific research has gone into the Triassic coal deposits. The Triassic coals in South Africa were the first coals to be exploited for their thermal use in the 1880s, but the discovery of the higher rank and more abundant Ecca coal deposits led to the Triassic coals remaining largely unexplored. The demand for rare earth elements has sparked interest in these coal deposits as potential sources for valuable minerals. Late Triassic coal deposits in Lesotho have previously not been well documented and these low-rank coals can be a potential source of rare earth elements. This study aims to characterize and evaluate the potential of REY in the Taung coal deposit, southwest of Lesotho. Coal and associated argillaceous samples from the Taung coal deposit were analyzed using microscopic petrography for coal characterization and an inductively coupled plasma mass spectrometry (ICP-MS) to determine the amount of rare earth elements. Taung coal is classified as middle medium rank D bituminous coal. The total REY content in Taung coal and its associated rocks range from 162.9 ppm to 855.1 ppm, which is significantly higher than the upper continental crustal (UCC) average. The average critical REY concentration of samples from the Taung coal deposit is 189.4 ppm, which is three times higher than that of the Chinese Bayan Obo deposit. Samples classified as very promising and promising because of their outlook coefficients, are found to contain up to 77% of critical REY. It is envisioned that the area could be a prime deposit for these REY.

Evaluation of the characteristics of ferrite garnet films for magneto-optical control of materials

A setup based on a polarization microscope was developed to study the characteristics of two types of ferrite-garnet films with the chemical composition Lu1.51Ho0.56Bi0.93Fe4.1Al0.9O12. The parameters of the hysteresis loop, values of residual magnetization, and the saturation field of the studied films were determined experimentally. The domain structure period was estab-lished, and a compact device for visualizing defects in steel samples was created. Using this device, a series of experiments were conducted on test samples with cracks of various sizes, and magneto-optical images of the cracks were obtained. The hysteresis loop of the two types of ferrite-garnet films was constructed in the “magnetiza-tion coefficient-magnetic field induction” coordinates. The magnetization coefficient was cal-culated based on the relative change in the area of bright and dark domains when the external magnetic field, directed perpendicular to the film plane, was varied. The efficiency of using two types of films, grown under different technological conditions but having the same chemical composition, in non-destructive testing methods was analyzed. It was found that the investigated films had the same domain period, but their residual magnetization and saturation field values varied significantly. Diagrams of the experimental setup and the developed device, as well as the characteristics of some of their components, are presented. To generate the magnetic field in the test samples, a coil wound on a U-shaped ferrite core was used, pressed against the sample surface on the opposite side relative to the crack location. The experiments were conducted under constant magnetic fields of varying intensity. The device was tested on specially prepared test samples with pre-grown cracks of known sizes. The tests demonstrated that films with higher residual magnetization and saturation field values were more sensitive to detecting defects such as enclosed cracks.

RVE Simulations of short fiber reinforced polyamide: Direct and inverse matrix parameter identification in view of the semi-crystalline polymer structure

This paper investigates the modeling capabilities of computational homogenization for the mechanical behavior of short fiber reinforced polyamide. Simulations on a representative volume element (RVE) with elastic fibers and an elastic–plastic matrix are compared to tensile experiments on specimens taken in parallel and transversal direction from injection molded plates. In view of the semi-crystalline polymer structure, focus is put on identifying the matrix parameters through two alternative methods:First, the matrix parameters are identified directly using tensile experiments on a non-nucleated and a nucleated unreinforced polyamide. In the RVE computations based on the non-nucleated grade, the composite stress–strain behavior is somewhat underestimated, and with the nucleated grade, the behavior is slightly overestimated. To explain this, the semi-crystalline polymer structure is studied. Polarized light microscopy images reveal that the non-nucleated grade has a coarser and the nucleated grade a finer spherulite structure, compared to the matrix present in the composite. However, the degree of crystallinity measured by differential scanning calorimetry is in a similar range.As an alternative, the matrix parameters are identified inversely by fitting the RVE model to the composite tensile experiments. As uncertainties with respect to the matrix material as well as possibly remaining simplifications in the micromechanical model are compensated for, this reverse engineering approach allows for a very good fit.

Achieving High Piezoelectric Performance Across Multidomains Design in K(Ta,Nb)O3-Based Lead-free Single Crystals.

In light of environmental issues, the lead-free ferroelectric single crystal K(Ta1-xNbx)O3 (KTN) has attracted considerable interest due to its excellent piezoelectric properties. This research focus on improving the piezoelectric performance of KTN by engineering domains through polarization in the [011]c direction. The full-matrix parameters of KTN crystals after polarization along the [011] direction were determined. The finding reveal that KTN polarized in the nonspontaneous polarization direction [011]c exhibits higher piezoelectric constants (d33 = 156 pC/N, d15 = 155 pC/N) and dielectric constants (ε33T ∼ 2337). Additionally, tensor matrix transformation techniques were utilized to analyze the directional dependence of the piezoelectric (d33*), dielectric (ε33T*), elastic (s33E*) constants, and electromechanical coupling coefficient (k33*). The results indicate that these constants reach their maximum values along the polarized [011]c direction. A comparison of the experimental polarization values in the [011]c direction with those calculated for a single-domain state, demonstrates that ferroelectric domains in KTN crystals contribute significantly to the piezoelectric properties. Finally, polarized light microscopy was used to conduct a detailed analysis of the domain structure in KTN single crystals, revealing various orientations and sizes of domain walls. This research offers strategies for optimizing piezoelectric performance.

Carbon dots induced homeotropic alignment in a negative dielectric nematic liquid crystal material

Abstract Recently, doping guest materials such as quantum dots (QDs) into liquid crystals (LCs) has been of great interest since their addition substantially enhances the properties of LC and opens new avenues for scientific advancement. Here, we report the induction of homeotropic alignment in cells without alignment layers of the negative dielectric nematic liquid crystal, N-(4-Methoxybenzylidene)-4-butylaniline (MBBA) by doping with carbon dots (CDs ∼2.8 ± 0.72 nm). The CDs-MBBA composites (CDs concentration: 0.002, 0.01, 0.03, 0.1 and 0.3 wt%) were investigated using optical polarising microscopy, electro-optical and dielectric techniques. Polarizing optical micrographs and voltage dependent optical transmission revealed the induced homeotropic alignment for all the composites under investigation. Interestingly, the least concentrated sample, 0.002 wt% exhibited partial homeotropic alignment. However, due to light leakage, the optical transmission value below threshold voltage was relatively higher than the rest of the composites. MBBA is a negative dielectric material, hence the application of a voltage across the cell was able to switch the alignment from a dark to a bright state for all composites. However, above a certain voltage (>threshold voltage), the bright state produced some instabilities. The value of dielectric permittivity was observed to decrease with increasing concentration, confirming the effect of CDs in producing homeotropic alignment in MBBA. Measurements as a function of temperature were conducted to examine the thermal stability of the induced alignment. The alignment was found to be stable throughout the nematic phase of MBBA. The induction of such alignment without conventional alignment (i.e., rubbing of polyimides) technique can be helpful in addressing the evolving display demands by making liquid crystal displays (LCDs) and other display devices cost effective.

POxylated stereocomplexes from PEtOx-b-PLA diblock copolymers

An ω-hydroxyl terminated poly(2-ethyl-2-oxazoline) (PEtOx) was obtained by termination of the cationic ring-opening polymerization of 2-ethyl-2-oxazoline with acetate and subsequent transesterification with methanol. The resulting PEtOx-OH featuring a degree of polymerization (DP) of 18 was used as a macroinitiator for the ring-opening polymerization of l-lactide as well as d-lactide. The resulting PEtOx-b-PLA block copolymers featured DP values of 25, 50, 100, and 150, respectively, and were characterized by means of size exclusion chromatography, 1H NMR spectroscopy as well as matrix-assisted laser desorption ionization mass spectrometry. Differential scanning calorimetry, wide-angle x-ray scattering and polarized light microscopy indicated the formation of stereocomplexes in racemic blends of PEtOx-b-PLA with opposing chirality. Thereby, the amorphous PEtOx block did not affect the modification of the stereocomplex crystallites, as shown by comparison with data obtained from PLA homopolymer stereocomplexes. Similar to those, the degree of crystallinity and melting temperature decreased with increasing molar mass of the PLA in the stereocomplexes formed from PEtOx-b-PLA block copolymers.

Liquid crystal and emulsifying properties of carboxymethyl glucoside as water-soluble surfactant

ABSTRACT Three derivatives of glucosides derived from n-dodecyl alcohol in a highly pure β-anomer were synthesised with the aim to yield the liquid crystalline phase at ambient temperature with improved water solubility. Effect of variation in headgroup polarity on thermal properties, liquid crystalline phases, and structures of these derivatives of n-dodecyl β-D-glucoside (β-GlcC12) has been examined through differential scanning calorimetry, optical polarising microscopy, and small- and wide-angle X-ray scattering, respectively. Derivative bearing two carboxymethyl and two hydroxyl groups at the sugar ring i.e. n-dodecyl 2,3-bis-O-[carboxymethyl]-β-D-glucopyranoside (2,3-diCOOH-β-GlcC12) exhibited lamellar phase at the room temperature in anhydrous condition by significantly reduced the melting and clearing temperatures compared to parent compound β-GlcC12. Under excess water condition, 2,3-diCOOH-β-GlcC12 was completely soluble to form a normal micellar solution. We further investigated its foaming performance and emulsifying ability in n-octane, n-dodecane, and n-hexadecane as the oil phase. Both aqueous solution of 2,3-diCOOH-β-GlcC12 emulsified with n-dodecane and n-hexadecane formed oil-in-water emulsion layer of more than 95% of the total system volume with n-dodecane/water system consistently maintains smaller particle sizes and a narrower polydispersity index. This supports the stronger emulsifying ability and better colloidal stability of the 2,3-diCOOH-β-GlcC12 in the n-dodecane/water system than in the n-hexadecane/water system.

Interplay of calcium pyrophosphate crystals, oxidative stress, and clinical features on knee osteoarthritis severity.

Deposition of calcium pyrophosphate (CPP) crystals is observed in most joints affected by severe osteoarthritis (OA). CPP may cause local damage by inducing an inflammatory process and oxidative stress (OS). To evaluate inflammation and OS induced by CPP deposition and their association with the degree of knee OA. Synovial fluid (SF) from patients with OA classified as grade 3 and 4 (ACR criteria) was analyzed. Reactive oxygen species (ROS) and H2O2 levels were quantified, and inflammation by white blood cell (WBC) count. CPPs were detected by polarized light microscopy. Multifactorial dimensionality reduction (MDR) was used to visualize possible interactive effects between variables. Fifty-six SF were analyzed, 22 (39.28%) were in moderate OA and 34 (60.71%) in severe OA. CPPs were identified in 17 moderate OA and 18 severe OA samples. In the moderate OA, ROS levels were significantly higher in the CPP + group (5.0% vs 2.0%, P = 0.03). Body mass index and CPP were significantly correlated (r = - 0.439, P = 0.041). In the severe OA group, there were significant correlations of age with WBC (r = - 0.431, P = 0.011), WBC with H2O2 (r = 0.454, P = 0.007), and ROS with H2O2 (r = 0.387, P = 0.024). MDR analysis revealed strong synergistic interactions between H2O2 and sex (6.68%) for moderate OA, while for severe OA, there were interactions between sex and ROS (6.99%) and between sex and inflammation (4.39%). ROS and inflammation may be factors that potentiate damage in knee OA, and this may help in the development of antioxidant interventions for CPP-associated OA. Key Points • This study evaluated CPP crystal-induced oxidative stress and inflammation and their effect on OA severity. • In the moderate OA phenotype, CPP crystals modify ROS levels. • ROS and inflammation are factors that increase damage in knee OA, especially when CPP crystals are present.

Quasi-visualizable detection of deep sub-wavelength defects in patterned wafers by breaking the optical form birefringence

Abstract In integrated circuit (IC) manufacturing, fast, nondestructive, and precise detection of defects in patterned wafers, realized by bright-field microscopy, is one of the critical factors for ensuring the final performance and yields of chips. With the critical dimensions of IC nanostructures continuing to shrink, directly imaging or classifying deep-subwavelength defects by bright-field microscopy is challenging due to the well-known diffraction barrier, the weak scattering effect, and the faint correlation between the scattering cross-section and the defect morphology. Herein, we propose an optical far-field inspection method based on the form-birefringence scattering imaging of the defective nanostructure, which can identify and classify various defects without requiring optical super-resolution. The technique is built upon the principle of breaking the optical form birefringence of the original periodic nanostructures by the defect perturbation under the anisotropic illumination modes, such as the orthogonally polarized plane waves, then combined with the high-order difference of far-field images. We validated the feasibility and effectiveness of the proposed method in detecting deep subwavelength defects through rigid vector imaging modeling and optical detection experiments of various defective nanostructures based on polarization microscopy. On this basis, an intelligent classification algorithm for typical patterned defects based on a dual-channel AlexNet neural network has been proposed, stabilizing the classification accuracy of λ/16-sized defects with highly similar features at more than 90%. The strong classification capability of the two-channel network on typical patterned defects can be attributed to the high-order difference image and its transverse gradient being used as the network’s input, which highlights the polarization modulation difference between different patterned defects more significantly than conventional bright-field microscopy results. This work will provide a new but easy-to-operate method for detecting and classifying deep-subwavelength defects in patterned wafers or photomasks, which thus endows current online inspection equipment with more missions in advanced IC manufacturing.