High-resolution Optical Microscopy Research Articles

Characteristics and utility of high-resolution optical coherence microscopy images of endocervical canal lesions.

To investigate optical coherence microscopy (OCM) imaging features and the application value of these high-resolution images for identifying endocervical canal lesions (ECLs), which is a clinical dilemma in cervical cancer screening programs. In total, 520 OCM images were obtained by scanning the cervical canal lesions with an ultra-high-resolution OCM system (204 specimens from 73 patients). The OCM morphologic characteristics of ECLs were observed and summarized, and then 3 researchers performed a diagnostic test of OCM images of cervical canal lesions. The accuracy, sensitivity, specificity, positive predictive value, negative predictive value, 95% confidence interval of each parameter, and interinvestigator agreement (κ) were calculated. Normal endocervix, cysts, squamous metaplasia, high-grade squamous intraepithelial lesions involving glands, and invasive carcinoma had distinct OCM characteristics, which correlated well with corresponding H&E histologic sections. The accuracy, sensitivity, and specificity of the 3 researchers were 90.6%, 89.3% (95% CI, 86.5%-91.7%) and 91.6% (95% CI, 89.2%-93.5%), respectively. The positive predictive value was 90.1% (95% CI, 87.3%-92.4%), and the negative predictive value was 90.9% (95% CI, 88.5%-92.9%), with almost perfect agreement (κ = 0.874). The application of the OCM system in cervical canal lesions is feasible and could help improve detection of occult ECLs in cervical cancer screening programs. This study lays the foundation for further research on OCM in cervical canal lesions in vivo, which also has a potential impact on projecting pathologic evaluation beyond what is currently possible, perhaps globally.

A Perspective Review: Analyzing Collagen Alterations in Ovarian Cancer by High-Resolution Optical Microscopy.

High-grade serous ovarian cancer (HGSOC) is the predominant subtype of ovarian cancer (OC), occurring in more than 80% of patients diagnosed with this malignancy. Histological and genetic analysis have confirmed the secretory epithelial of the fallopian tube (FT) as a major site of origin of HGSOC. Although there have been significant strides in our understanding of this disease, early stage detection and diagnosis are still rare. Current clinical imaging modalities lack the ability to detect early stage pathogenesis in the fallopian tubes and the ovaries. However, there are several microscopic imaging techniques used to analyze the structural modifications in the extracellular matrix (ECM) protein collagen in ex vivo FT and ovarian tissues that potentially can be modified to fit the clinical setting. In this perspective, we evaluate and compare the myriad of optical tools available to visualize these alterations and the invaluable insights these data provide on HGSOC initiation. We also discuss the clinical implications of these findings and how these data may help novel tools for early diagnosis of HGSOC.

Abstract 3935: Involvement of nanoscale physical communication in obesity-associated breast cancer severity

Abstract Obesity is a risk factor for several cancers, including breast cancer, and contributes up to 20% of cancer-related deaths. Growing evidence from both clinical and preclinical studies indicates that increased obesity is associated with increases in cancer incidence, progression, metastasis, and therapeutic resistance. According to the Centers for Disease Control and Prevention (CDC), more than 70% and 40% of American adults can be classified as overweight and obese, respectively. However, treatment strategies for dealing with cancer in obese patients have not advanced apart from lifestyle interventions. However, several signaling mechanisms have been proposed related to the inflammatory and metabolic impact of obese adipocytes in promoting cancer progression. However, a lack of mechanistic understanding led to no specific treatment strategies have been proposed which can specifically downregulate the key regulator by which obese adipocytes promote cancer progression. Thus, translational research initiatives are immediately needed to provide mechanistic justifications for these striking statistics in order to better serve this growing segment of the population. Here, we have shown the role of nanoscale physical communication between breast cancer cells and adipose tissue in promoting cancer progression. Using high-resolution optical and electron microscopy, we have found that breast cancer cells form nanoscale tubular communications with obese adipocytes. Moreover, the cancer cells hijack mitochondria from obese adipocytes. However, coculturing cancer cells and obese adipocytes in the Boyden chamber, allowing exosomal and paracrine communication but blocking direct physical communication, revealed negligible mitochondria transfer. This observation indicates an active transfer of mitochondria via nanotube. A significantly higher rate of mitochondria transfer from obese adipocytes to cancer cells has been observed than non-differentiated pre-adipocytes. The transfer of mitochondria results in an increase in the metabolism of the cancer cells. The mechanistic investigation of the nanotube formation revealed actin's presence as the major component in the nanotube. The exocyst-GTPase protein complex has a prime contribution in actin remodeling and nanotube formation. Inhibition of exocyst-GTPase using a pharmacological inhibitor results in a significant reduction in nanotube-mediated mitochondria transfer. Conclusion: Our goal is to (i) investigate the direct physical connection between adipocytes and cancer cells and the effect on cancer progression and (ii) eliminate mortality related to obesity-associated breast cancer severity by introducing a new therapeutic strategy. Here, we have shown how cancer cells communicate with obese adipocytes and receive additional metabolic power for proliferation. The in vivo investigation of the same is under progress. Citation Format: Tanmoy Saha, Balaaji Baanupriya Srinivasan, Shiladitya Sengupta. Involvement of nanoscale physical communication in obesity-associated breast cancer severity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3935.

Anatomy, histology and ultrastructure of the digestive tract in Andean fish (Trichomycterus bogotensis) and ecological implications

AbstractTrichomycterus bogotensis is one of the three species of fish that inhabit the Colombian Andes. However, several aspects of its basic biology, including its digestive system, are unknown. The morphology and histology of the digestive system are of great importance for understanding a species’ feeding habits and food preferences. Thus, this study aimed to perform a morphological description of the digestive tract of T. bogotensis. The gastrointestinal tract of seven specimens was processed for paraffin histology, high-resolution optical microscopy, and transmission electron microscopy. Anatomically, T. bogotensis exhibits a terminal mouth with villiform teeth, a narrow esophagus, a large and muscular stomach, and a short intestine. Histology and ultrastructure revealed a tissue organization similar to that reported for other Silurids, composed of four layers: mucosal, submucosal, muscular, and serosa. The anatomical and histological characteristics suggest that T. bogotensis is a benthic species with a tendency to carnivory.

Evaluating Nanoparticles Penetration by a New Microfluidic Hydrogel-Based Approach.

Reliable predictions for the route and accumulation of nanotherapeutics in vivo are limited by the huge gap between the 2D in vitro assays used for drug screening and the 3D physiological in vivo environment. While developing a standard 3D in vitro model for screening nanotherapeutics remains challenging, multi-cellular tumor spheroids (MCTS) are a promising in vitro model for such screening. Here, we present a straightforward and flexible 3D-model microsystem made out of agarose-based micro-wells, which enables the formation of hundreds of reproducible spheroids in a single pipetting. Immunostaining and fluorescent imaging, including live high-resolution optical microscopy, can be done in situ without manipulating spheroids.

Heptatic liquid quasi-crystals by colloidal lithographic pre-assembly

HypothesisWe hypothesize that pre-assembled lithographic Brownian seven-fold quasi-crystals (QCs) of colloidal tiles at high densities can exhibit a heptatic liquid quasi-crystal (LQC) phase upon release; such heptatic LQCs can undergo heterogeneous dynamics at different length scales, reflecting the underlying symmetry, corrugation, and hierarchy of local sets of tiles. ExperimentsWe design, fabricate, and release a seven-fold QC composed of three differently shaped rhombic tiles using the method of lithographically pre-assembled monolayers (litho-PAMs). High resolution optical microscopy enables spatio-temporal particle tracking of Brownian fluctuations of many tiles in a large area over a long time. We develop an edge-proximity tessellation method for analyzing nearest neighboring particles that can be applied to assemblies and dense systems of complex shapes. FindingsA fluctuating heptatic LQC phase is identified at high tile area fractions. Heterogenous dynamics and order at different length scales indicate diverse, hierarchical motif structures. We show that certain motifs can collectively rotate without any cage breaking, leading to alterations of the local tile-structure reminiscent of phason-flips in atomic QCs; this rotation causes a slow decline in the system's spatial order. We anticipate that edge-proximity tessellation will help elucidate phase transitions of other systems made of diverse building blocks having significant geometrical complexity at multiple length scales.

Nanoscale and ultrafast in situ techniques to probe plasmon photocatalysis

Plasmonic photocatalysis uses the light-induced resonant oscillation of free electrons in a metal nanoparticle to concentrate optical energy for driving chemical reactions. By altering the joint electronic structure of the catalyst and reactants, plasmonic catalysis enables reaction pathways with improved selectivity, activity, and catalyst stability. However, designing an optimal catalyst still requires a fundamental understanding of the underlying plasmonic mechanisms at the spatial scales of single particles, at the temporal scales of electron transfer, and in conditions analogous to those under which real reactions will operate. Thus, in this review, we provide an overview of several of the available and developing nanoscale and ultrafast experimental approaches, emphasizing those that can be performed in situ. Specifically, we discuss high spatial resolution optical, tip-based, and electron microscopy techniques; high temporal resolution optical and x-ray techniques; and emerging ultrafast optical, x-ray, tip-based, and electron microscopy techniques that simultaneously achieve high spatial and temporal resolution. Ab initio and classical continuum theoretical models play an essential role in guiding and interpreting experimental exploration, and thus, these are also reviewed and several notable theoretical insights are discussed.

Metal Core-Shell Nanoparticle Supercrystals: From Photoactivation of Hydrogen Evolution to Photocorrosion.

Gas nanobubbles are directly linked to many important chemical reactions. While they can be detrimental to operational devices, they also reflect the local activity at the nanoscale. Here, supercrystals made of highly monodisperse Ag@Pt core-shell nanoparticles are first grown onto a solid support and fully characterized by electron microscopies and X-ray scattering. Supercrystals are then used as a plasmonic photocatalytic platform for triggering the hydrogen evolution reaction. The catalytic activity is measured operando at the single supercrystal level by high-resolution optical microscopy, which allows gas nanobubble nucleation to be probed at the early stage with high temporal resolution and the amount of gas molecules trapped inside them to be quantified. Finally, a correlative microscopy approach and high-resolution electron energy loss spectroscopy help to decipher the mechanisms at the origin of the local degradation of the supercrystals during catalysis, namely nanoscale erosion and corrosion.

Reactive transport modeling for assessing coupled hydrogeochemical processes at interfaces in deep geological repositories: from the laboratory to the real world

Abstract. Deep geological repositories with a multi-barrier concept are foreseen by various countries for the disposal of high-level radioactive waste. Simulation tools for a close-to-reality description of repository evolution scenarios are required, especially to resolve the challenging task of comparing and assessing the long-term safety of different repository concepts in different host rocks within the German site-selection process. Chemical, thermal, and pressure gradients at the interfaces of the different barriers in a repository can lead to mineral dissolution and precipitation, generating non-linear responses in transport and mechanical properties of barrier materials and host rocks. Reactive transport modeling (RTM) can be applied to investigate these perturbations and processes across temporal and spatial scales to assess subsurface evolution. Nevertheless, implementing RTM at the continuum scale while accounting for pore-scale heterogeneities and geometry evolution remains a challenge. Pore-scale simulations offer the potential to capture the complex evolution of porous media over a broad range of Peclet and Damköhler numbers, and they can be utilized to improve the RTM by using upscaling methods (Prasianakis et al., 2020). In this context, we developed “lab-on-a-chip” experiments, combining time-lapse high-resolution optical microscopy and confocal Raman spectroscopy to test extended constitutive equations to classically employed Archie's law to improve the description of changes in transport properties (e.g., diffusivity) in evolving porous media in RTM. The 3D Raman tomography of the porous media combined with pore-scale modeling enabled the derivation of upscaled transport parameters. Our results highlight the importance of calibrating pore-scale models with quantitative experiments prior to simulations over a wide range of Peclet and Damköhler numbers, whose results can be further used for the derivation of upscaled modeling parameters. The derived and parameterized constitutive equations based on simple systems have been tested in reactive transport models as a sensitivity case study to evaluate uncertainties in the predictions of the evolution of real subsurface systems such as clay–cement interfaces in deep geological repositories.

(Invited) Innovative Membrane Electrode Assemblies for the Next Generation Proton Exchange Membrane Water Electrolyzers

The Hydrogen Economy (HE) is the economy of the near future and is the only viable alternative to the current fossil fuel-based economy. This future green economy will eliminate the greenhouse gas emissions and stop the imminent global warming and climate change. The HE implementation relies on the development of zero-carbon emission technologies for Hydrogen (H2) production. “Green” hydrogen can be produced at large scale by integration of water electrolyzers (WEs) with renewable energy sources. Currently, the proton exchange membrane water electrolyzers (PEMWEs) are considered to be the most advanced WEs that can be integrated with solar panels and wind turbines to produce large quantities of green H2. The main challenges that the state-of-the-art membrane electrode assemblies (MEAs) for PEMWEs are currently facing are: (i) high cost because of the high platinum group metals (PGM) loadings in their catalysts layers (2-3 mgPGM/cm2 in each electrode), and time consuming and expensive multi-step fabrication processes associated with their manufacturing; (ii) limited durability caused by the instability of the catalysts and the other cell components, and (iii) safety concerns associated with the hydrogen gas crossover and the absence of technologies that can effectively keep it below the safety level of the lower flammability limit (LFL) [1, 2, 3].In this work, we demonstrate the capabilities of a unique methodology for fabrication of advanced catalysts, catalyst layers, and MEAs for PEMWEs, known as Reactive Spray Deposition Technology (RSDT). The RSDT is a flame assisted method [4, 5] that combines the catalysts synthesis and deposition directly on the PEM membrane in one-step, which results in fast and facile fabrication of large scale (up to 1000 cm2) MEAs for application in PEM fuel cells and water electrolyzers [5, 6]. This technology allows precise control of the composition, morphology, and particle size distribution of a wide range of nanoparticles, supported and unsupported on carbon, and ensures fine tuning of the catalysts’ activity and durability. MEAs with geometric areas of 86 cm2 and 680 cm2, both with one order of magnitude lower PGM loading in their catalyst layers in comparison to the state-of-the-art MEAs for PEM water electrolyzers [6,7], are fabricated by the RSDT and evaluated for up to 5000 hours at current density of 1.8 A cm-2, 50 oC, and 400 psi differential hydrogen pressure. Diagnostic tests that include polarization curves, electrochemical impedance spectroscopy, linear sweep voltammetry, and hydrogen crossover measurements are performed periodically in order to evaluate the cell performance change during the long-term durability test. After the test, the MEAs are disassembled and subjected to comprehensive post test analysis. A wide range of techniques, including high-resolution TEM, STEM, EDS, SEM, ICP, XCT, XPS, and digital optical microscopy, have been used to study the degradation mechanisms governing the performance loss in the MEAs during the long-term steady state operation. The results from these tests will be presented and discussed in detail in this talk.References https://www.energy.gov/sites/prod/files/2017/05/f34/fcto_myrdd_fuel_cells.pdf https://www.energy.gov/sites/prod/files/2015/06/f23/fcto_myrdd_production.pdfKlose, P. Trinke, T. Böhm, B. Bensmann, S. Vierrath, R. Hanke-Rauschenbach, and S. Thiele, J. Electrochem. Soc., 165, F1271–F1277 (2018).Kim, S., Myles, Maric, R., et al. Electrochimica Acta, 177, 190-200 (2015).Yu, H., Baricci, A., Bisello, A., Bonville, L., Maric, R., et al. Electrochimica Acta, 247, 1155-1168 (2017).Mirshekari, G., Ouimet, R., Zeng, Z, Yu, H., Bliznakov, S., Bonville, L., Niedzwiecki, A., Errico, S., Capuano, C., Mani, P., Ayers, K., Maric, R. International Journal for Hydrogen Energy, 46(2), 2021, pp. 1526-1539 (2021).Ayers, K. Current Opinion in Electrochemistry, 18, 9–15 (2019).

Multiscale dynamics of charging and plating in graphite electrodes coupling operando microscopy and phase-field modelling

The phase separation dynamics in graphitic anodes significantly affects lithium plating propensity, which is the major degradation mechanism that impairs the safety and fast charge capabilities of automotive lithium-ion batteries. In this study, we present comprehensive investigation employing operando high-resolution optical microscopy combined with non-equilibrium thermodynamics implemented in a multi-dimensional (1D+1D to 3D) phase-field modeling framework to reveal the rate-dependent spatial dynamics of phase separation and plating in graphite electrodes. Here we visualize and provide mechanistic understanding of the multistage phase separation, plating, inter/intra-particle lithium exchange and plated lithium back-intercalation phenomena. A strong dependence of intra-particle lithiation heterogeneity on the particle size, shape, orientation, surface condition and C-rate at the particle level is observed, which leads to early onset of plating spatially resolved by a 3D image-based phase-field model. Moreover, we highlight the distinct relaxation processes at different state-of-charges (SOCs), wherein thermodynamically unstable graphite particles undergo a drastic intra-particle lithium redistribution and inter-particle lithium exchange at intermediate SOCs, whereas the electrode equilibrates much slower at low and high SOCs. These physics-based insights into the distinct SOC-dependent relaxation efficiency provide new perspective towards developing advanced fast charge protocols to suppress plating and shorten the constant voltage regime.

Examining the impact of cement on porosity evolution in the upper triassic Kurra Chine Formation of Sirwan valley, Kurdistan region, Iraq: A study integrating cathodoluminescence and scanning electron microscopy

The study of carbonate petrography is essential for understanding reservoir properties and the quality of rock formations. High-resolution cathodoluminescence spectroscopy and optical microscopy were used to determine the impact of cement on the porosity evolution of carbonate rocks of the Kurra Chine Formation at Sirwan Valley, Northern Iraq. This study represents the first-ever attempt to investigate sedimentology at this location. A total, of 183 thin-section slides, 18 X-Ray Diffraction (XRD) samples, 14 Scanning Electron Microscope (SEM) samples, and 6 Cathodoluminescence (CL) samples were analyzed from the outcrop section of the Kurra Chine Formation. Four types of dolomite textures are recognized and classified based on the crystal size distribution and crystal-boundary shape. The porosity within Kurra Chine Formation includes primary and secondary porosity, with the majority of primary porosity being occluded by cementation. Cathodoluminescence analysis revealed two phases of calcite cement in the Kurra Chine Formation. The first phase (C1), is characterized by weak-zoned blocky calcite, displaying a dull luminescence with typical homogenous red color, which fills most of the interparticle and moldic pores. The second type of calcite cement (C2) is ghost-zoned calcite exhibiting red to slight orange luminesces interfingering with dolomite cement. XRD analysis indicated a predominant of calcite and common dolomite. SEM analysis revealed the predominance of secondary porosity occurring within fractures of the dolomite.

Ultrastructural skin alterations of healthy subjects with anti-desmoglein 1 antibodies in endemic areas to pemphigus foliaceus: A case series

BackgroundEndemic pemphigus foliaceus and endemic pemphigus vulgaris are autoimmune dermatologic disorders endemic to the Peruvian Amazon. ObjectiveTo determine the ultrastructural skin alterations of three healthy subjects with anti DSG-1 antibodies in areas endemic to pemphigus foliaceus and pemphigus vulgaris in the Peruvian Amazon. Patients and methodsCase series carried out from data of three clinically healthy subjects positive to anti DSG-1 antibodies, from Peru. This study consists of a sub-analysis of data gathered in a previous study. ResultsUltrastructural results are presented from the skin biopsies of three clinically healthy patients positive to anti-desmoglein 1 (DSG-1) antibodies. High Resolution Optical Microscopy (HROM) showed the absence of acantholysis. Transmission Electron Microscopy (TEM) showed the widening of intercellular space between keratinocytes, the presence of vacuoles in intercellular space with granular material and cytoplasmic vacuolization, loss of desmosome structure, loss of normal distribution among tonofilaments and lateral separation among cells in the stratum basale. ConclusionAccording to our results, healthy subjects that present anti-desmoglein 1 antibodies can develop ultrastructural alterations that are visible through transmission electron microscopy but not through conventional optical microscopy.

Detailed investigation of zinc coating behaviours in various deep eutectic solvents

Determining the optimum conditions of a metal coating is significant for its possible applications in many fields. The present work described the electrodynamic process of zinc coating from six different deep eutectic solvents (DESs), especially type-III DES systems prepared with a quaternary ammonium salt and hydrogen bond type. Non-reversible processes without oxidation were found in DES systems prepared with choline chloride and zinc nitrate salts, and also, propylene glycol and zinc nitrate salts, termed as type-II and type-IV, respectively. The most attracted type-III DES prepared by a mixture of 1 molar choline chloride and 2 molar ethylene glycols, commercially known as Ethaline (E200), were examined for its electronucleation and possible reactions for zinc electrodeposition. For the first time, the Pt working electrode was investigated under high-resolution optical microscopy to visualize the in-situ morphology change during oxidation and reduction in E200. Furthermore, the morphological change during the anodic dissolution of zinc was also investigated in situ under a high-resolution microscope. It was found that insoluble species forming during anodic dissolution blocks the surface. Bulk electrolysis was performed in these solvents to investigate the formed zinc nucleates' morphological differences. XRD analysis was performed to differentiate the crystal planes of each deposition obtained from six DESs. It was found that the type-II and type-IV DESs consisting of zinc nitrates revealed zinc hydroxy nitrate dominated zinc deposition, which can be helpful in various applications.

A New Imidazole Derivative for Corrosion Inhibition of Q235 Carbon Steel in an Acid Environment.

Q235 carbon steel is a commonly used engineering material, but its application in marine environments is limited by its susceptibility to corrosion, especially localized corrosion that can lead to material perforation. Effective inhibitors are crucial to addressing this issue, particularly in acidic environments where localized areas become increasingly acidic. This study reports the synthesis of a new imidazole derivative corrosion inhibitor and evaluates its effectiveness in corrosion inhibition performance using potentiodynamic polarization curve and electrochemical impedance spectroscopy techniques. High-resolution optical microscopy and scanning electron microscopy were employed for surface morphology analysis. Fourier-transform infrared spectroscopy was used to explore the protection mechanisms. The results demonstrate that the self-synthesized imidazole derivative corrosion inhibitor offers an excellent corrosion protection performance for Q235 carbon steel in a 3.5 wt. % NaCl acidic solution. This inhibitor can provide a new strategy for carbon steel corrosion protection.

Structural Peculiarities of Natural Ballas—Spheroidal Variety of Polycrystalline Diamond

Ballas is a rare polycrystalline diamond variety characterized by a radially oriented internal structure and spheroidal outer shape. The origin of natural ballases remains poorly constrained. We present the results of a comprehensive investigation of two classic ballas diamonds from Brazil. External morphology was studied using SEM, high-resolution 3D optical microscopy, and X-ray tomography. Point and extended defects were examined on polished central plates using infra-red, photo- and cathodoluminescence spectroscopies, and electron back-scattering diffraction; information about nanosized inclusions was inferred from Transmission Electron Microscopy. The results suggest that fibrous diamond crystallites comprising ballas are split with pronounced rotation, causing concentric zoning of the samples. Pervasive feather-like luminescing structural features envelop single crystalline domains and most likely represent fibers with non-crystallographic branching. These features are enriched in N3 point defects. Twinning is not common. The nitrogen content of the studied samples reaches 700 at.ppm; its concentration gradually increases from the center to the rim. Annealing of the ballases took place at relatively high temperatures of 1125–1250 °C; the annealing continued even when the samples were fully grown, as suggested by the presence of the H4 nitrogen-related defects in the outer rim. Presumably, the ballas diamond variety was formed at high supersaturation but in conditions favoring a small growth kinetic coefficient. The carbon isotopic composition of the studied ballases (δ13C = −5.42, −7.11‰) belongs to the main mode of mantle-derived diamonds.

Real-time observation of the freezing stage of the mannitol solution using high-resolution optical microscopy

Vacuum freeze-drying has been expanding its influence in many fields, and the freezing stage is of utmost importance for the freeze-drying process. However, the limited understanding of the freezing stage has posed a major challenge for developing the vacuum freeze-drying process. An experimental setup was designed and employed in this paper to experimentally investigate the freezing stage of the mannitol solution. The cooling rate and solute mass fraction are chosen as the key freezing parameters. The nucleation temperature, the morphology and velocity of the freezing front, the morphology and size distribution of the ice crystals at the combination of different freezing conditions were studied. The results show that the nucleation temperature (supercooling degree) distribution could be better described by the Gauss distribution. The morphology of the freezing front is more strongly affected by the cooling rate compared with the mass fraction. In addition, the morphology of ice crystals also exhibits differences under different freezing conditions. The average size decreases with the increase of the cooling rate, while the uniformity of particle size distribution increases when increasing the cooling rate. The research could help deepen the understanding of the freezing stage in a qualitative way, and provide a reference for the theoretical research.

Giovanna Garzoni Miniaturist at the Savoy Court: Imaging and Materials Investigations to Discover the Painting Technique

The exhibition “The Ladies of Art”, held at the Palazzo Reale in Milan in 2021, focused on the history of women artists during the 16th and 17th centuries. As part of the exhibition, a series of diagnostic analyses have been carried out on two paintings, thanks to the collaboration of several research institutions. The considered artworks consist of two paintings on parchments, realized by Giovanna Garzoni at the Savoy Court in the 17th century. Diagnostic analyses were performed using different, complementary, and non-invasive techniques: high-resolution multiband imaging, hyperspectral imaging, optical microscopy, X-ray fluorescence, and FORS spectrometry, combined with advanced post-processing techniques, in order to map and distinguish the pigments and the underdrawing of both the paintings. This research is the first conducted on these paintings and one of the few on the entire works of this important miniaturist. The results showed an incredibly meticulous painting technique, with a detailed metal point underdrawing and painstaking brushstrokes to describe the details with a high degree of realism. Precious materials, such as gold and lapislazuli, were identified and mapped. The findings of this work represent a new contribution of knowledge, which helps to lessen the lack of information for systematic studies on the artistic production of G. Garzoni.

Identification and highly selective differentiation of organic gunshot residues utilizing their elemental and molecular signatures

Firearm related evidence is of great significance to forensic science. In recent years, many researchers have focused on exploring the probative value of organic gunshot residue (OGSR) evidence, which is often bolstered by many factors including recoverability. In addition, OGSR analysis has shown the potential to achieve differentiation between OGSRs generated from various ammunition brands and/or calibers. Raman spectroscopy is a vibrational spectroscopic technique which has been used in the past for gunshot residue analysis—including OGSR specifically. Raman spectroscopy is a nondestructive, highly-selective, simple, and rapid technique which provides molecular information about samples. LIBS or Laser-Induced Breakdown Spectroscopy is a simple, robust, and rapid analytical method which requires minimal to no sample preparation and a small amount of sample for analysis. LIBS provides information on the elemental compositions of samples.In this study, Raman spectroscopy and LIBS were used together in sequence in an attempt to achieve the specific identification and characterization of OGSR particles from ammunition types which were closely related. The main goal was to determine if this method had the potential to differentiate between various ammunition types of the same caliber and produced by the same manufacturer, and generated under identical firing conditions. High-resolution optical microscopy documented the OGSR particles’ morphologies and Raman spectroscopy was used to identify particles as OGSRs. Finally, LIBS analysis of the OGSR particles was carried out. Advanced chemometric techniques were shown to allow for very successful differentiation between the OGSR samples analyzed.

Coassembled Nitric Oxide-Releasing Nanoparticles with Potent Antimicrobial Efficacy against Methicillin-Resistant Staphylococcus aureus (MRSA) Strains.

Nitric oxide (NO)-releasing nanoparticles are effective nanomedicines with diverse therapeutic advantages compared with small molecule-based NO donors. Here, we report a new class of furoxan-based NO-releasing nanoparticles using a simple, creative yet facile coassembly approach. This is the first time we demonstrated that the coassembled NO-releasing nanoparticles with poly(ethylene glycol)101-block-poly(propylene glycol)56-block-poly(ethylene glycol)101 (Pluronic F127) had potent antimicrobial efficacies against methicillin-resistant Staphylococcus aureus (MRSA) strains. Nanoparticles obtained from the coassembly of either 4-(1-(3-methylpentan-5-ol)oxyl)(3-phenylsulfonyl) furoxan (compound 1) or 4-methoxy(3-phenylsulfonyl) furoxan (compound 2) with Pluronic F127 exhibit 4-fold improved antimicrobial activities compared to their self-assembled counterparts without Pluronic F127. 5(6)-Carboxylfluorescein (CF) leakage experiments further reveal that both coassembled NO-releasing nanoparticles show stronger interactions with lipid bilayers than those self-assembled alone. Subsequently, their strong plasma membrane-damaging capabilities are confirmed under both high-resolution optical microscopy and scanning electron microscopy characterizations. This coassembly approach could be readily applied to other small molecule-based antimicrobials, providing new solutions and important insights to further antimicrobial recipe design.