Laser Ablation Research Articles

Surface engineering and selection of materials for lunar regolith adherence characterization

As the quest for long-term lunar exploration and habitation comes closer to reality, widespread efforts are ongoing to effectively mitigate lunar dust surface contamination and infiltration. This dust is hazardous to humans and tends to adhere tenaciously to all exposed surfaces, causing performance issues and ultimately failure. While several active and passive technologies have been developed to address this challenge, assessing the performance of these technologies in the lunar environment is required. The Regolith Adherence Characterization experiment payload scheduled to be flown to the lunar surface in 2024 provides an important opportunity for this evaluation. A limited number of material testing slots were available to the NASA Langley Research Center for this mission, so it was critical to make an informed selection. Two polymers, Kapton® HN and Teflon™ FEP, a carbon fiber reinforced bismaleimide composite, and a titanium alloy, Ti–6Al–4V, were chosen to be a diverse selection of structural materials from the NASA Langley Research Center. Each material was topographically modified using laser ablation patterning. This article describes the selection, surface modification, terrestrial characterization, and performance evaluation for these passive dust mitigating materials.

Synthesis of High Entropy Alloy Nanoparticles by Pulsed Laser Ablation in Liquids: Influence of Target Preparation on Stoichiometry and Productivity

AbstractHigh entropy alloys (HEAs) have a wide range of applications across various fields, including structural engineering, biomedical science, catalysis, magnetism, and nuclear technology. Nanoscale HEA particles show promising catalytic properties. Nevertheless, attaining versatile composition control in nanoparticles poses a persistent challenge. This study proposes the use of pulsed laser ablation in liquids (PLAL) for synthesizing nanoparticles using equiatomic CoCrFeMnNi targets with varied preparation methods. We evaluate the impact of target preparation method on nanoparticle yield and composition as well as the magnetic properties of the nanoparticles. The elemental powder‐pressed heat‐treated target (HEA‐PP), identified as the most time‐efficient and cost‐effective, exhibits noticeable segregation and non‐uniform elemental distribution compared to ball milled hot‐pressed powder (HEA‐BP) and face‐centered cubic (FCC) single crystal (HEA‐SX) alloy targets. From all targets, nanoparticles (sizes from 2 to 120 nm) can be produced in ethanol with a nearly equiatomic CoCrFeMnNi composition and a FCC structure, showing oxidation of up to 20 at.%. Nanoparticles from HEA‐PP exist in a solid solution state, while those from HEA‐BP and HEA‐SX form core‐shell structures with a Mn shell due to inhomogeneous material expulsion, confirmed by mass spectrometry. HEA‐PP PLAL synthesis demonstrates 6.8 % and 15.1 % higher productivity compared to HEA‐BP and HEA‐SX, establishing PLAL of elemental powder‐pressed targets as a reliable, time‐efficient, and cost‐effective method for generating solid solution HEA nanoparticles.

Mucocele Treatment in Pediatric Patient at RSGM UMY

Background : Mucoceles is minor salivary gland lession. The extravasation mucocele, commonly referred to as a "mucous retention cyst," does not have an epithelial lining or a well-defined boundary. An extravasation mucocele is believed to be caused by damage to a tiny salivary gland excretory duct. Saliva accumulates in the adjacent submucosal tissue due to a tear in the duct, leading to swelling. Retention type mucocele occurs when a small salivary gland duct is blocked, often by a sialolith, periductal scarring, or tumor. Salivary flow blockage leads to the accumulation of saliva and the enlargement of the duct. Objective : To provide treatment for mucocele in a pediatric patient at RSGM UMY Case Report : A 9-year-old patient came to RSGM UMY accompanied by his mother, complain he has swelling on lower lip. He often bite the lower lip for a long time. It is painless and sometimes increases in size. His experiencing discomfort due to the bump. Method : The mucocele was excised using infiltration anesthetic and a blade no. 15. Surgical sutured silk braided was utilized for postoperative wound closure. The patient was provided with post-operative instructions and prescribed antibiotics and analgesics. The patient was scheduled for a follow-up appointment after one week to have the sutures removed. Result : No complaints after control 1 month and 3 months after treatment Conclusion : Surgical removal remains the optimal choice for treating mucoceles due to its simplicity and cost-effectiveness compared to laser ablation, cryosurgery, and electrocautery

Durable anti-fog micro-nano structures fabricated by laser ablation of aluminum film on resin/glass

This study presents a technique for processing transparent glass and resin substrates using a low-cost laser marker to create a micro-nano-structured surface with exceptional anti-fog properties. The approach involved depositing an aluminum (Al) film on the transparent substrates as an absorbing layer, followed by rapid laser marker ablation. This ablation process effectively removed the majority of the Al film, resulting in the formation of hierarchical hillock-hollow micro-structures and the dispersion of Al-based nano-particles throughout the surface. The resulting structure on resin glasses demonstrated anti-fog performance even after 629 days storage in the laboratory, which marked the longest antifog record. It exhibited impressive antifog property without visible degradation for the first 9 months, which though degraded substantially afterwards. Furthermore, the micro-nano structure played a key role in reducing the contact angle of the surface. The contact angle experienced a significant reduction from a value of 64° for the control resin to 6.9° for the treated resin, while it was reduced from 44° for the control glass to 0° for the treated glass, indicating superhydrophilicity. This 0° superhydrophilic state persisted for a period of 25 days.

An in vitro assessment of the residual dentin after using three minimally invasive caries removal techniques

To evaluate the efficiency and effectiveness of three minimally invasive (MI) techniques in removing deep dentin carious lesions. Forty extracted carious molars were treated by conventional rotary excavation (control), chemomechanical caries removal agent (Brix 3000), ultrasonic abrasion (WOODPECKER, GUILIN, China); and Er, Cr: YSGG laser ablation (BIOLASE San Clemente, CA, USA). The assessments include; the excavation time, DIAGNOdent pen, Raman spectroscopy, Vickers microhardness, and scanning electron microscope combined with energy dispersive X-ray spectroscopy (SEM–EDX). The rotary method recorded the shortest excavation time (p < 0.001), Brix 3000 gel was the slowest. DIAGNOdent pen values ranged between 14 and 18 in the remaining dentin and laser-ablated surfaces recorded the lowest reading (p < 0.001). The Ca:P ratios of the remaining dentin were close to sound dentin after all excavation methods; however, it was higher in the ultrasonic technique (p < 0.05). The bur-excavated dentin showed higher phosphate and lower matrix contents with higher tissue hardness that was comparable to sound dentin indicating the non-selectiveness of this technique in removing the potentially repairable dentin tissue. In contrast, the MI techniques exhibited lower phosphate and higher organic contents associated with lower microhardness in the deeper dentin layers. This was associated with smooth residual dentin without smearing and patent dentinal tubules. This study supports the efficiency of using MI methods in caries removal as conservative alternatives to rotary excavation, providing a promising strategy for the clinical dental practice.

Intraoperative Assessment of the Stromal Ablation in Photorefractive Keratectomy.

Purpose: To evaluate the difference between planned and measured central ablation depth (CAD) and compare the first and second operated eye in simultaneous bilateral myopic alcohol-assisted PRK. Methods: A retrospective review of patients was performed. Demographic and preoperative data was abstracted. Intraoperative assessment included environmental data, laser-planned algorithm of ablation (L-CAD), and optical coherence pachymetry (OCP) measurements. The true stromal ablation depth (O-CAD) was calculated by subtracting the immediate post-ablation OCP measurement from the OCP measurement before laser ablation. Deviation in pachymetry (DP) between O-CAD and L-CAD was also assessed. Results: The study comprised 140 eyes from 70 consecutive patients. The mean age was 26.91 ± 6.52 years, and 57.1% were females. O-CAD was significantly correlated to preoperative refractive errors and intraoperative laser settings. DP was not correlated to any of the pre- or intraoperative parameters. L-CAD showed a significant underestimation as compared to O-CAD (67.87 ± 25.42 µm and 77.05 ± 30.79 µm, respectively, p < 0.001), which was shown in 74.3% of the cases. A moderate agreement between the two methods was noted, with a mean deviation of 17%. This difference was maintained for each eye individually (p < 0.001). In addition, DP was significantly higher in the first operated eye as compared to the second operated eye (11.97 ± 16.3 µm and 6.38 ± 19.3 µm respectively, p = 0.04). Conclusion: The intraoperative assessment of stromal ablation showed significantly higher central ablation depth values compared to the laser-planned ablation algorithm. The deviation in pachymetry was higher in the first, compared to the second, operated eye. Awareness is warranted as to the discrepancy between preoperative planning and intraoperative assessment.

A computational model to understand the interaction of nanosecond pulsed laser with ultra-thin SiN[formula omitted] layer-coated silicon substrate

Nanosecond lasers can be used for the selective ablation of ultra-thin SiNx layer (80–100 nm) coated on a silicon substrate with applications in the fabrication of PERC solar cells. Experiments reveal that the ablation process can occur in different regimes with material removal in solid, liquid, vapor, and explosion forms. This study investigates the different regimes for single pulse ablation through a physics-based model developed using the finite volume method in Ansys Fluent. The model accounts for various physical phenomena, including laser heating, melting, thermal expansion, thermal decomposition, Marangoni convection, vaporization, plasma formation, melt expulsion, and phase explosion. Experiments were conducted using Nd: YVO4 laser (λ=532 nm, pulse duration = 50 ns), and the measured single pulse crater profiles are in excellent agreement with the model predictions over a broad range of laser fluence. Results show that the SiNx layer breaks due to the thermal expansion of the underlying silicon at lower fluences (3.05–3.35 J/cm2) in a very narrow range. Above this fluence range lies another narrow range (3.35–5.55 J/cm2) wherein the SiNx layer is thermally decomposed into silicon and nitrogen, and craters are formed due to Marangoni convection in the melt pool formed. Ablation due to vaporization occurs in a broad fluence range (5.55–8.4 J/cm2), causing deeper ablation depths and material deposition at the crater edge. At higher fluences (¿8.4 J/cm2), explosive boiling occurs due to homogeneous nucleation, resulting in much higher ablation depths (¿1.6μm), broader crater widths, and poor surface finish. This model provides an understanding of different material removal regimes in laser ablation of SiNx-coated silicon.

Binder-free laser induced graphene-MnO2 composite electrodes for high areal energy density flexible supercapacitors

The synthesis of Laser-Induced Graphene (LIG) through the laser ablation process of carbon-containing materials is a rapid and scalable process which enables the production of graphene in a cost-effective manner. In recent years, metal oxide – graphene composite electrodes have gained a lot of importance due to their use in various Energy Storage Devices (ESDs). In our investigation, we manufacture composite electrodes of manganese dioxide (MnO2) and LIG through a hydrothermal process and use it as electrodes in Flexible Supercapacitors. This method deviates from traditional procedures as it eliminates the requirement for binders in creating composite electrodes, given that MnO2 can be directly deposited onto the LIG electrodes. The assembled all-Flexible Supercapacitor (FSC), featuring unique LIG-MnO2 composite electrodes, showcased a remarkable areal capacitance of 66.5 mF cm−2 at 5 mV s−1 scan rate. The device also exhibited a very high areal energy density (2.3 mWh cm−2) and power density (19.7 mW cm−2) at 0.2 mA cm−2 current density. Also, 82 % capacitance retention was observed at the end of 2000 cycles and the device also exhibited a good flexibility during bending tests, as evidenced by an 80 % capacitance retention after 100 bending cycles.

Development of Transmission Ambient Pressure Laser Desorption Ionization/Postphotoionization Mass Spectrometry Imaging.

Laser-based high-resolution mass spectrometry imaging at ambient conditions has promising applications in life science. However, the ion yield during laser desorption/ablation is poor. Here, transmission atmospheric pressure laser desorption ionization combined with a compact postphotoionization (t-AP-LDI/PI) assembly with a krypton discharge lamp was developed for the untargeted imaging of various biomolecules. The spatial distributions of numerous lipid classes, fatty acids, neurotransmitters, and amino acids in the subregions of mouse cerebellum tissue were obtained. Compared with single laser ablation, the sensitivities for most analytes were increased by 1 to 3 orders of magnitude by dopant-assisted postphotoionization. After careful optimization, a spatial resolution of 4 μm could be achieved for the metabolites in mouse hippocampus tissue. Finally, the melanoma tissue slices were analyzed using t-AP-LDI/PI MSI, which revealed the metabolic heterogeneity of the melanoma microenvironment and exhibited the phenomenon of abnormal proliferation and invasion trends in tumor cells.

U−Pb geochronology and microstructural analysis of apatite within a Proterozoic crustal-scale shear zone, Outer Hebrides, NW Scotland

U–Pb apatite geochronology is increasingly recognized as a valuable tool for constraining the age of mid-crustal ductile shear zones. The crustal-scale Outer Hebrides Fault Zone (OHFZ) within the Laurentian foreland of the Scottish Caledonides has long been of uncertain age and tectonic significance. Earliest deformation within the OHFZ was associated with top-to-the-NW ductile thrusting that formed a belt of greenschist facies mylonites within host Archean−Paleoproterozoic basement gneisses. Previous estimates for the timing of thrusting vary between c . 1600 Ma and c . 430 Ma. The mylonitic fabrics are defined by a recrystallized assemblage of quartz + albite/oligoclase + sericite + actinolite + epidote + apatite ± calcite, consistent with deformation temperatures of 400–500°C and within the range of reported closure temperatures for Pb diffusion in apatite. U–Pb (LA−ICP−MS) dating of two texturally distinct apatite grain types within the mylonites has yielded ages mostly in the range c . 1100–900 Ma. The OHFZ is therefore interpreted as a Grenville–Sveconorwegian structure that formed during the tripartite collision of Laurentia, Baltica, and Amazonia and the assembly of Rodinia. Supplementary material : U–Pb isotopic data (Table S1), trace element data (Table S2) and laser ablation spot images are available at https://doi.org/10.6084/m9.figshare.c.7084925

Silver Nanoparticles as Antiviral and Antibacterial Agents: A Comprehensive Review of Synthesis Methods and Therapeutic Application

AbstractSilver nanoparticles have shown inhibitory capabilities and its use in battling viral infections are strengthened by its potent antibacterial activity. Notably, since it directly affects antiviral efficacy, the proper choice of synthesis process for making silver nanoparticles is a vital element to be taken into consideration. The synthesis of silver nanoparticles for the treatment of viral and bacterial infections involves creating silver particles at the nanoscale with unique antimicrobial properties. Various methods exist for synthesizing silver nanoparticles, including chemical reduction, green synthesis, and physical methods. Chemical reduction involves using reducing agents to convert silver ions into silver nanoparticles. Green synthesis employs reducing agents in an environmentally friendly manner. Physical methods rely on techniques such as laser ablation or thermal evaporation to produce silver nanoparticles. In order to provide technological guidance for choosing antiviral silver nanoparticle manufacturing methods, this paper introduces and explores alternative synthesis methods for creating silver nanoparticles.

Comparison of efficacy and safety of different minimally invasive therapies for thyroid nodules: A network meta-analysis.

This study aimed to compare efficacy and safety of minimally invasive therapies such as radiofrequency ablation (RFA), microwave ablation (MWA), ethanol ablation (EA), and laser ablation (LA) for thyroid nodules through network meta-analysis (NMA). This study searched PubMed, Web of Science, Embase, and The Cochrane Library databases to collect randomized controlled trials (RCTs) or cohort studies comparing efficacy and safety of different minimally invasive therapies for thyroid nodules. Newcastle-Ottawa Scale (NOS) was implemented to assess quality of included cohort studies, and Cochrane risk of bias assessment tool was utilized to evaluate quality of included RCTs. Eligible studies contained at least one of the following clinical outcome measures: volume reduction rate (VRR), symptom score, cosmetic score, nodule regrowth rate, and complication rate. STATA software was utilized for NMA. Sixteen eligible studies (4 RCTs, 11 retrospective cohort studies, 1 prospective cohort study) involved 4094 patients. NMA results revealed that RFA group had the highest VRR at 1 months and 12 months. There were no significant differences in symptom scores and cosmetic scores among all treatment methods, with the lowest symptom scores and cosmetic scores in RFA group. LA group had a significantly higher nodule regrowth rate than RFA and MWA groups, with the lowest in RFA group. There were no significant differences in complication rate among all treatment methods. RFA had the highest VRR for thyroid nodules, and it excelled in symptom scores, cosmetic scores, and nodule regrowth rates.

Microwave versus endovenous laser in great saphenous vein ablation: a randomized controlled clinical study

Background Due to the global burden of varicose veins (VVs) and the impact on the quality of life (QoL) of patients, it is essential to search for better treatment modalities. Objectives The main objective of this research was to compare the efficacy, safety, and impact on the QoL of endovenous microwave ablation (EMA) and endovenous laser ablation (EVLA) for the management of varicose veins of the great saphenous vein (GSV). Methods A comparative, multicenter, single-blinded, parallel randomized controlled study conducted on 340 patients confirmed to have primary VVs of the GSV who were further randomized into two groups. The study group (n=170) received EMA, and the control group (n=170) received EVLA. Results Both the study group and the control group were comparable with regard to their baseline characteristics (P values &gt; 0.05). The study group and the control group were comparable with regard to the limb affected (P=0.184). Only 14.7% and 10.0% of the study group and the control group have both limbs affected. Both the study group and the control group were comparable with regard to CEAP classification (P=0. 068). The study group and the control group were significantly different with regard to operating time (P&lt;0.001). The operating time is less in the study group than in the control group. The median (IQR) and the mean±SD of the operating time was 7 (4) and 8.7±4.1 min in the study (microwave) group and 9 (5) and 10±3.9 min in the control group. Also, the study group and the control group showed 100% success at the 1-week evaluation as none of the cases in both groups suffered recanalization. At 6-month evaluation, only 1 case in the study group and 2 cases of the control group experienced recanalization; however, the difference is not significant (P=0.537). At the 12-month evaluation, the study group and the control group showed 100% success as none of the cases in both groups suffered recanalization. QoL is better in the study group than the control group at 6 months Aberdeen score (P=&lt; 0.001). The median IQR and the mean±SD of the postoperative Aberdeen score were 9 (2.7) and 9.3±1.7 in the study (microwave) group and 10.8 (3.4) and 10.8±1.8 in the control group. Moreover, the study group and the control group were comparable (P values &gt; 0.05) with regard to adverse events except for paresthesia (P-value = 0.025). About 11.2% of the control group experienced paresthesia versus only 2.9% of the study group. Conclusion In conclusion, EMA has a lower operating time than EVLA. EMA is as effective as EVLA for treating VVS of the GSV. EMA has fewer adverse events than EVLA. EMA has better QoL than EVLA ablation. However, the choice of treatment should be based on individual patient characteristics and the expertise of the treating physician.

Abstract 4949: Multimodal analysis of metals, spatial transcriptomics, and histological structures in colorectal cancer

Abstract Colorectal Cancer (CRC) accounts for nearly 10% of all cancer cases and is the second-leading cause of cancer-related deaths worldwide. The increased incidence of CRC in younger demographics underscores the need for improved screening and prognostication. These enhancements are crucial to augment staging practices which focus on accurate evaluation of local lymph node involvement and distant metastasis. Essential trace elements such as copper and iron within the tumor microenvironment (TME) present novel therapeutic strategies- e.g., copper in cell proliferation/signaling and iron in pro-tumorigenic pathways, amongst other multifaceted roles. Despite advancements in spatial imaging/sequencing for detailed mapping of elemental abundance and gene expression profiles at near-subcellular resolution, the understanding of metal signaling and transport pathways in tumors is limited. This gap highlights the need for sophisticated informatics software for data integration and analysis. We developed a computational workflow for spatial multimodal analysis of elements, genes, cell-types, and histological features, applied to a unique CRC case (pT3) as proof-of-concept. Elemental imaging at 5-micron resolution was performed using laser ablation inductively coupled plasma time-of-flight mass spectrometry (LA-ICPTOF-MS). The 10x Genomics Visium spatial transcriptomic (ST) CytAssist assay captured spatial variation in gene expression within 55-micron spots, with 40X H&amp;E-stained whole slide imaging (Leica Aperio GT450). Cell type proportions within spots were determined through integration of single cell RNASeq. Regions within, around and away from tumor were annotated by a pathologist. ST and LA-ICPTOF-MS were integrated through co-registration software developed at Biomedical National Elemental Imaging Resource. Local Getis-Ord spatial statistics defined hotspots with high elemental concentration. Wilcoxon tests were used to perform differential expression analysis based on metal hotspots, followed by identification of associated biological pathways through Enrichr with Bonferroni adjustment. Preliminary findings revealed distinct trace element distributions in the TME. For instance, Copper was localized within tumor, correlating with pathways related to immune response and activation (overlap=10/89, p&amp;lt;0.0001). Iron was found concentrated at the proliferative front of the tumor, associated with the epithelial to mesenchymal transition pathway and extracellular matrix remodeling (overlap=25/291, p&amp;lt;0.0001), as well as with a mesenchymal phenotype (W=11.7, p&amp;lt;0.0001), identified through cell type deconvolution. Future work will expand on these findings across multiple tissue contexts as means to capture biological processes governing tumor metastasis, recurrence and survival for biomarker discovery and therapeutics development. Citation Format: Aruesha Srivastava, Neha Shaik, Yunrui Lu, Matthew Chan, Alos Diallo, Serin Han, Ramsey Steiner, Tracy Punshon, Brian Jackson, Linda Vahdat, Louis Vaickus, Jack Hoopes, Fred Kolling, Jonathan Marotti, Joshua Levy. Multimodal analysis of metals, spatial transcriptomics, and histological structures in colorectal cancer [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 4949.

A Non-Disposable Electrochemical Sensor Based on Laser-Synthesized Pd/LIG Nanocomposite-Modified Screen-Printed Electrodes for the Detection of H2O2.

There have been many studies on the significant correlation between the hydrogen peroxide content of different tissues or cells in the human body and the risk of disease, so the preparation of biosensors for detecting hydrogen peroxide concentration has been a hot topic for researchers. In this paper, palladium nanoparticles (PdNPs) and laser-induced graphene (LIG) were prepared by liquid-phase pulsed laser ablation and laser-induced technology, respectively. The complexes were prepared by stirring and used for the modification of screen-printed electrodes to develop a non-enzymatic hydrogen peroxide biosensor that is low cost and mass preparable. The PdNPs prepared with anhydrous ethanol as a solvent have a uniform particle size distribution. The LIG prepared by laser direct writing has good electrical conductivity, and its loose porous structure provides more adsorption sites. The electrochemical properties of the modified electrode were characterized by cyclic voltammetry, chronoamperometry, and electrochemical impedance spectroscopy. Compared with bare screen-printed electrodes, the modified electrodes are more sensitive for the detection of hydrogen peroxide. The sensor has a linear response range of 5 µM-0.9 mM and 0.9 mM-5 mM. The limit of detection is 0.37 µM. The above conclusions indicate that the hydrogen peroxide electrochemical biosensor prepared in this paper has great advantages and potential in electrochemical catalysis.

Abstract 7429: A web-based application to co-register elemental imaging with histopathology to enhance the study of metal bioaccumulation within tumors

Abstract Essential trace elements are crucial in various biological processes, including tumor growth, migration, and metastasis. For instance, copper ions are involved in mitochondrial metabolism, cell proliferation, tumor migration, metastasis and proangiongenic pathways. Localizing where metal ion homeostasis is disrupted is vital for understanding these processes beyond what bulk analysis can reveal. Elemental imaging offers high-resolution, quantifiable multi-elemental distribution maps, providing a more detailed analysis compared to traditional bulk measurements. However, aligning findings with tissue structures identified in histopathological data can be challenging. To address this, we developed a web-based application for the co-registration and analysis of Whole Slide Images (WSI) and elemental imaging data at the cellular level. The application integrates WSI with elemental maps generated by technologies such as ultrafast laser ablation and inductively coupled plasma time-of-flight mass spectrometry (LA-ICP-TOF-MS), as well as a range of other elemental imaging techniques. Hosted by the Biomedical National Elemental Imaging Resource, the current application allows for a streamlined data integration, co-registration, and analysis, including: 1) uploading WSI, elemental maps, and pathologist annotations, 2) automated preprocessing to identify tissue regions, 3) co-registration to merge WSI and elemental maps, 4) custom import, real-time overlay/editing of pathologist annotations transferred from WSI, 5) plotting, statistical tools and 6) data export. This application enables users to compare elemental abundance within/between tissue structures annotated on H&amp;E or immunohistochemical slides. Derived data can pinpoint elements and mixtures whose abundance differs significantly across various pathological conditions. As an initial test, we applied the software on breast HER2/ER/PR tumors, varying in molecular subtype/histology. Preliminary results, using Bayesian lognormal regression models, adjusting for tumor subtypes, indicated a subtype-dependent variation in copper abundance. The relative difference in copper levels between tumor and stromal regions was notably less in HER2 tumors (p=0.026) compared to HR tumors (p&amp;lt;0.0001). Conversely, iron showed a consistently higher abundance in stromal areas across both subtypes (p&amp;lt;0.0001). Future enhancements include improved co-registration capabilities, hotspot analysis, machine learning, mixture effects, and cloud-based architecture. This method uniquely enables integration of elemental data with spatial transcriptomics, mapping gene transcripts on tissue slides. With current ST assays aligned with H&amp;E slides, this tool facilitates co-registration, offering insights into biological pathways affected by metal homeostasis disruptions. Citation Format: Yunrui Lu, Ramsey Steiner, Serin Han, Matthew Chan, Tracy Punshon, Brian Jackson, Linda Vahdat, Jonathan Marotti, Joshua Levy. A web-based application to co-register elemental imaging with histopathology to enhance the study of metal bioaccumulation within tumors [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 7429.

Formation of multiple ion types during MALDI imaging mass spectrometry analysis of Mitragyna speciosa alkaloids in dosed rat brain tissue

Mitragyna speciosa, more commonly known as kratom, has emerged as an alternative to treat chronic pain and addiction. However, the alkaloid components of kratom, which are the major contributors to kratom's pharmaceutical properties, have not yet been fully investigated. In this study, matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry was used to map the biodistribution of three alkaloids (corynantheidine, mitragynine, and speciogynine) in rat brain tissues. The alkaloids produced three main ion types during MALDI analysis: [M + H]+, [M − H]+, and [M − 3H]+. Contrary to previous reports suggesting that the [M − H]+ and [M − 3H]+ ion types form during laser ablation, these ion types can also be produced during the MALDI matrix application process. Several strategies are proposed to accurately map the biodistribution of the alkaloids. Due to differences in the relative abundances of the ions in different biological regions of the tissue, differences in ionization efficiencies of the ions, and potential overlap of the [M − H]+ and [M − 3H]+ ion types with endogenous metabolites of the same empirical formula, a matrix that mainly produces the [M + H]+ ion type is optimal for accurate mapping of the alkaloids. Alternatively, the most abundant ion type can be mapped or the intensities of all ion types can be summed together to generate a composite image. The accuracy of each of these approaches is explored and validated.

Post-fabrication adjustment of metalloid Mg–C-graphene nanoparticles via Pulsed Laser Ablation for paper electronics and process optimisation

Metalloid nanoparticles (MNPs) possess unique physicochemical properties but are challenging to create through biological or chemical routes. Using Pulsed Laser Ablation in Liquid (PLAL), Mg–C MNPs are fabricated from powders. The produced nanocolloids were ablated after the target was removed to tailor the particle size. MNPs with a mean size 300 nm could be reduced to 60 nm. Alternatively, MNPs with a mean size of 60 nm could be increased to 90 nm. The increase/decrease in size is controlled by the laser processing parameters and showcases the ability of PLAL for real-world applications that require meticulous control of size. The as-fabricated nanocolloids were successfully inkjet printed on paper, achieving a low resistivity of 75 Ω/square after 60 prints, highlighting their potential in printed electronics. To address a historical research gap, this article explored the impact of PLAL processing parameters, including fluence (1–2 J/cm2), pulse width (0.2–0.9 ns), repetition rate (10–20 kHz), and pH, factors often overlooked which is partly limiting applications. The influence of powder vs rod target on the PLAL process was addressed revealing that powders produce better size control and are easier to handle but they produce lower colloid concentrations.

Synthesis and Unique Behaviors of High-Purity HEA Nanoparticles Using Femtosecond Laser Ablation.

High-entropy alloys (HEAs) are a class of metal alloys consisting of four or more molar equal or near-equal elements. HEA nanomaterials have garnered significant interest due to their wide range of applications, such as electrocatalysis, welding, and brazing. Their unique multi-principle high-entropy effect allows for the tailoring of the alloy composition to facilitate specific electrochemical reactions. This study focuses on the synthesis of high-purity HEA nanoparticles using the method of femtosecond laser ablation synthesis in liquid. The use of ultrashort energy pulses in femtosecond lasers enables uniform ablation of materials at significantly lower power levels compared to longer pulse or continuous pulse lasers. We investigate how various femtosecond laser parameters affect the morphology, phase, and other characteristics of the synthesized nanoparticles. An innovative aspect of our solution is its ability to rapidly generate multi-component nanoparticles with a high fidelity as the input multi-component target material at a significant yielding rate. Our research thus focuses on a novel synthesis of high-entropy alloying CuCoMn1.75NiFe0.25 nanoparticles. We explore the characterization and unique properties of the nanoparticles and consider their electrocatalytic applications, including high power density aluminum air batteries, as well as their efficacy in the oxygen reduction reaction (ORR). Additionally, we report a unique nanowire fabrication phenomenon achieved through nanojoining. The findings from this study shed light on the potential of femtosecond laser ablation synthesis in liquid (FLASiL) as a promising technique for producing high-purity HEA nanoparticles.

Geochemical proxies for deep-sea temperature and nutrient content in cold-water bamboo corals

The impact of warming, acidification, and deoxygenation on deep-sea environments is a growing concern. Historical records are sparse, particularly at high latitudes, making climate change projections challenging. Indirect proxies, such as trace element composition of marine carbonates, such as coral skeletons, can offer an alternative method to fill data gaps but have not been realised. Here, using Laser Ablation Triple-Quadrupole Inductively Coupled Plasma Mass Spectrometry (LA-QQQ-ICP-MS), we examined micrometre-scale element variation within and between individual colonies of the bamboo coral Keratoisis sp. obtained from the Eastern Canadian Arctic. These data are used to assess the influence of biological variability on geochemical tracers for reconstructing past environmental conditions (temperature: Mg/Ca, Li/Mg, Sr/Ca, Ba/Ca, U/Ca; [Ba]SW: Ba/Ca). We place these data into context, based on a survey of literature data, using refined calibrations for high-Mg calcitic Octocorals. We find reproducible (2σ relative coefficient of variation) values of Mg/Ca (3%) and Ba/Ca (6%) along the radial growth axis of all colonies and internodes of Keratoisis sp., indicating that these signals are likely suitable for environmental reconstructions. After revising the available multi-taxa calibrations for Mg/Ca (0.316 ± 0.026 °C/mmol/mol, R2 = 0.87, p < 0.001) and Ba/Ca ([Ba/Ca μmol/mol] = 0.148 ± 0.005 [BaSW nmol/kg], R2 = 0.97, p < 0.001), we show that vital effects within and among Keratoisis sp. colonies strongly influence reconstructed temperature and [Ba]SW, but this can be somewhat mitigated by combining multiple internode transects from one colony into a single composite series. Despite the ontogenetic variability, all colonies reveal a gradual deep-water cooling trend since the early 21st century and synchronised, multi-year spikes in Ba/Ca (and hence [Ba]SW) that suggest substantial and coherent barium inputs to the seafloor. Our study confirms the reliability of Mg/Ca and Ba/Ca proxies in high-Mg bamboo corals for detecting multi-annual temperature and seawater barium variations in cold-water environments, but further investigation into micro-scale element behaviour influenced by biotic processes in these corals is needed to enhance confidence in reconstructions at finer spatial and temporal resolutions. We conclude that employing empirical calibrations based on multi-taxa approaches can increase the certainty of capturing regional changes in the environment more accurately than a single species calibration, while leveraging multiple element series to account for biological-induced variability improves single colony reconstructions.