Colloidal platinum nanoparticles enhance resin-dentin bonding durability.

OBJECTIVES: This study aims to investigate the effect of colloidal platinum nanoparticles (CPN) on the durability of resin-dentin bonding performance with contemporary adhesives. METHODS: Sixty non-carious human maxillary premolars were subjected to microtensile bond strength (µTBS) testing and divided into two main groups: CPN-treated and untreated. Within each group, specimens were randomly allocated to Clearfil Megabond 2 (MB2), Scotchbond Universal Plus Adhesive with self-etch mode (SE-SUP), and etch-and-rinse mode (ER-SUP) subgroups (n = 10/group). CPN was applied to dentin in the MB2 and SE-SUP groups for 20 s, followed by rinsing before adhesive application. In the ER-SUP group, CPN was applied after etch-and-rinse. The µTBS was tested after 24 h, 6 months, and 1 year, and the fracture modes were observed using SEM. The µTBS data were analyzed using a two-way ANOVA and post-hoc Tukey HSD test (α = 0.05). An additional twelve premolars underwent TEM/STEM/EDX for ultra-morphological observations. RESULTS: The application of CPN significantly prevented a decline in the µTBS of both the MB2 and SE-SUP groups. No significant decrease was observed in the ER-SUP group, either with aging or CPN application. Ultra-morphological images revealed platinum nanoparticles attaching to the collagen fibrils of the hybrid layer regardless of aging. It was highlighted that the nanoparticles attached to the banded collagen in the aging groups were observed. SIGNIFICANCE: CPN exhibits the potential in enhancing the longevity of resin-dentin bonding in SE mode.

Specific iron binding to natural sphingomyelin membrane induced by non-specific co-solutes.

HYPOTHESIS: Sphingomyelin (SPM), a crucial phospholipid in the myelin sheath, plays a vital role in insulating nerve fibers. We hypothesize that iron ions selectively bind to the phosphatidylcholine (PC) template within the SPM membrane under near-physiological conditions, resulting in disruptions to membrane organization. These interactions could potentially contribute to the degradation of the myelin sheath, thereby playing a role in the development of neurodegenerative diseases. EXPERIMENTS: We utilized synchrotron-based X-ray spectroscopy and diffraction techniques to study the interaction of iron ions with a bovine spinal-cord SPM monolayer (ML) at the liquid-vapor interface under physiological conditions. The SPM ML serves as a model system, representing localized patches of lipids within a more complex membrane structure. The experiments assessed iron binding to the SPM membrane both in the presence of salts and with additional evaluation of the effects of various ion species on membrane behavior. Grazing incidence X-ray diffraction was employed to analyze the impact of iron binding on the structural integrity of the SPM membrane. FINDINGS: Our results demonstrate that iron ions in dilute solution selectively bind to the PC template of the SPM membrane exclusively at near-physiological salt concentrations (e.g., NaCl, KCl, KI, or CaCl2) and are pH-dependent. In-significant binding was detected in the absence of these salts or at near-neutral pH with salts. The surface adsorption of iron ions is correlated with salt concentration, reaching saturation at physiological levels. In contrast, multivalent ions such as La3+ and Ca2+ do not bind to SPM under similar conditions. Notably, iron binding to the SPM membrane disrupts its in-plane organization, suggesting that these interactions may compromise membrane integrity and contribute to myelin sheath damage associated with neurological disorders.

Cu-Atom Locations in Rocksalt SnTe Thermoelectric Alloy.

The development of functional thermoelectric materials requires direct evidence of dopants' locations to rationally design the electronic and phononic structure of the host matrix. In this study, Cs-corrected scanning transmission electron microscopy and energy dispersive X-ray spectroscopy is employed at the atomic scale to identify Cu atoms' locations in a Cu-doped SnTe thermoelectric alloy. It is revealed that Cu atoms in the rocksalt SnTe form solid solutions at both Sn and Te sites, contrary to their electronegativity order and the intentional Cu doping at Sn sites. Cu atoms are also located at the tetrahedral and crowdion sites of the face-centred cubic structure, with varying degrees of correlations. Such high flexibility of Cu atoms in the rocksalt SnTe offers diverse phonon-scattering mechanisms conducive to the ultra-low lattice thermal conductivity of singly Cu-doped SnTe. This study offers atomic-scale insights for achieving more precise dopant engineering, leading to the accelerated development of functional thermoelectric materials.

Surface and Mineral Changes of Primary Enamel after Laser Diode Irradiation and Application of Remineralization Agents: A Comparative In Vitro Study.

OBJECTIVES: The purpose of this study is to evaluate the remineralization potential of primary teeth enamel after being exposed to different laser diode therapies. METHODS: Ninety-six vestibular primary teeth enamel samples were divided into eight groups (n = 12) with varying treatments: control (G1), CPP-ACP-fluoride varnish (G2), diode lasers at 980 nm (G3), 808 nm (G4), 450 nm (G5), 980 nm + CPP-ACP-fluoride varnish (G6), 808 nm + CPP-ACP-fluoride varnish (G7), and 450 nm + CPP-ACP-fluoride varnish (G8). Each sample was assessed using a DIAGNOdent® (KaVo Dental, Biberach, Germany), at baseline, post-treatment, and post-pH cycle remineralization. SEM imaging was performed before and after treatment and following the pH cycle. RESULTS: The results indicated that the 980 nm and 808 nm diode lasers, both alone and in combination with CPP-ACP-fluoride varnish, either maintained or increased the calcium (Ca) weight percentage (Wt%) in the enamel. The 980 nm diode laser combined with CPP-ACP-fluoride varnish (G6) showed a significant increase in Ca Wt%, suggesting a strong remineralization effect. Similarly, the 808 nm diode laser alone (G4) also promoted a substantial increase in Ca Wt%. In contrast, the 450 nm diode laser, whether applied alone or in combination with CPP-ACP-fluoride varnish, resulted in a lower Ca Wt% and an increase in phosphorus (P) Wt%. Most groups, except for the CPP-ACP-fluoride varnish alone (G2), demonstrated an increase in P Wt%, indicating a complex interaction between laser therapy and enamel remineralization. CONCLUSIONS: The combined use of laser therapy with CPP-ACP-fluoride varnish significantly enhanced the remineralization of temporary teeth enamel. The 980 nm diode laser + CPP-ACP-fluoride varnish showed the most pronounced improvement in remineralization, while the 808 nm diode laser alone also effectively increased calcium solubility. These findings suggest that higher-wavelength diode lasers, particularly when combined with remineralizing agents, can effectively enhance the mineral content of primary teeth and promote enamel remineralization.

Uranium Speciation and Mobilization in Thawing Permafrost.

Uranium is a toxic and pervasive geogenic contaminant often associated with organic matter. Its abundance and speciation in organic-rich permafrost soils are unknown, thereby limiting our ability to assess risks associated with uranium mobilization during permafrost thaw. In this study, we assessed uranium speciation in permafrost soil and porewater liberated during thaw using active-layer and permafrost samples from a study area in Yukon, Canada where elevated uranium concentrations occur in bedrock and groundwater. Permafrost contained 1.1-28 wt % organic carbon and elevated uranium (range 7.6-1040 µg g-1, median 25 µg g-1) relative to local bedrock. The highest soil uranium concentrations were encountered in catchments hosting uranium-enriched bedrock and correlated positively with soil organic carbon. X-ray absorption spectroscopy, micro-X-ray fluorescence, and electron microscopy analyses revealed that solid-phase uranium predominantly occurs as uranium(VI) associated with soil organic matter. Extended X-ray absorption fine structure (EXAFS) analyses suggested the presence of uranium(VI) coordinated with carbon, consistent with bidentate-mononuclear uranyl complexation on carboxyl groups. Permafrost thaw produced circumneutral pH porewater (pH 6.2-7.5) with elevated dissolved uranium (0.5-203 µg L-1). Geochemical modeling indicated that calcium-uranyl-carbonate complexes dominated the dissolved uranium speciation. This study highlights that permafrost soil can mobilize uranium upon thaw and that uranium fate is linked to dynamic biogeochemical reactions involving organic carbon and groundwater chemistry.

Liquid Phase Electron Microscopy of Bacterial Ultrastructure.

Recent advances in liquid phase scanning transmission electron microscopy (LP-STEM) have enabled the study of dynamic biological processes at nanometer resolutions, paving the way for live-cell imaging using electron microscopy. However, this technique is often hampered by the inherent thickness of whole cell samples and damage from electron beam irradiation. These restrictions degrade image quality and resolution, impeding biological interpretation. Using graphene encapsulation, scanning transmission electron microscopy (STEM), and energy-dispersive X-ray (EDX) spectroscopy to mitigate these issues provides unprecedented levels of intracellular detail in aqueous specimens. This study demonstrates the potential of LP-STEM to examine and identify internal cellular structures in thick biological samples. Specifically, it highlights the use of LP-STEM to investigate the radiation resistant, gram-positive bacterium, Deinococcus radiodurans using various imaging techniques.

Influential reinforcement parameters, elemental mapping, topological analysis and mechanical performance of lignocellulosic date palm/epoxy composites for improved sustainable materials.

The value of biomaterials for green products has begun to develop more ecofriendly and renewable sustainable materials for a better circular economy and to reduce carbon footprints. This work presents integrated investigations of the lignocellulosic date palm/epoxy composites at various reinforcement condition parameters for sustainable structural materials where elemental mapping, topological analysis, and mechanical performance have been performed. Mapping energy dispersive X-ray spectroscopy was utilized to assess the composite composition properly. Elemental mapping and a scanning electron microscope were employed to evaluate the chemical composition of the composites. The mechanical performance of the produced composites was also explored in terms of ultimate tensile strength, tensile modulus, elongation at break, and impact energy properties. The effects of fiber loading, fiber length, and fiber width (as long fiber, short fiber, and long-thin fiber) were investigated for the date palm fiber/epoxy composites. Results have revealed that the composite behavior was affected by several influential reinforcement parameters. The energy dispersive X-ray spectroscopy maps by C-K, O-K, Si-K, K-K, and Ca-K demonstrated that the composites contain mainly carbon, silicon, and oxygen. It was evident that the modulus of elasticity property of short fiber composites exhibits an increasing trend with higher fiber content, even at 35 wt%. Moreover, the enhancement of tensile strength for the short fiber size composites reached 72.5 %. However, such tensile strength of thin fiber size/epoxy composites achieved 135.7 % at 25 wt% indicating superior development of this mechanical property. The long date palm fiber composites demonstrated the best value of modulus of elasticity and the maximum impact energy of 15.3 kJ/m2 attained at 25 wt%, which is about 112.5 % enhancement. Scan electron microscope was capable of confirming that broken fibers were not separated from the matrix indicating the good adhesion between the fiber and the matrix that supports their good mechanical performance.

Effect of hematoma on early degradation behavior of magnesium after implantation.

The corrosion of magnesium (Mg)-based bioabsorbable implanting devices is influenced by implantation environment which dynamically changes by biological response including wound healing. Understanding the corrosion mechanisms along the healing process is essential for the development of Mg-based devices. In this study, a hematoma model was created in a rat femur to analyze Mg corrosion with hematoma in the early stage of implantation. Pure Mg specimen (99.9%,ϕ1.2 × 6 mm) was implanted in rat femur under either hematoma or non-hematoma conditions. After a designated period of implantation, the specimens were collected and weighed. The insoluble salts formed on the specimen surfaces were analyzed using scanning electron microscopy, energy-dispersive x-ray spectroscopy, and Raman spectroscopy on days 1, 3, and 7. The results indicate that hematomas promote Mg corrosion and change the insoluble salt precipitation. The weight loss of the hematoma group (27.31 ± 5.91 µg mm-2) was significantly larger than that of the non-hematoma group (14.77 ± 3.28 µg mm-2) on day 7. In the non-hematoma group, carbonate and phosphate were detected even on day 1, but the only latter was detected on day 7. In the hematoma group, hydroxide was detected on day 1, followed by the formation of carbonate and phosphate on days 3 and 7. The obtained results suggest the hypoxic and acidic microenvironment in hematomas accelerates the Mg corrosion immediately after implantation, and the subsequent hematoma resorption process leads to the formation of phosphate and carbonate with organic molecules. This study revealed the risk of hematomas as an acceleration factor of the corrosion of Mg-based devices leading to the early implant failure. It is important to consider this risk in the design of Mg-based devices and to optimize surgical procedures controlling hemorrhage at implantation and reducing unexpected bleeding after surgery.

Investigations of airborne tire and brake wear particles using a novel vehicle design.

Non-exhaust emissions have become an increasingly important issue as their levels continue to rise and the health effects of particulate matter (PM) are more widely discussed. To address this issue, a vehicle demonstrator with integrated emission reduction of tires and brakes was developed as part of the Zero Emission Drive Unit Generation-1 (ZEDU-1) project. This novel concept includes the removal of tire road wear particles (TRWP) with a strong ventilation/filtering system and an enclosed multi-disk brake, making it a suitable tool for the investigation of non-exhaust emissions. Particle number (PN) and particle size distribution (PSD) measurements down to 2.5 nm were performed on a chassis dynamometer and on a test track. Due to the low background concentrations on the chassis dynamometer, it is possible to distinguish between tire and brake wear and to characterize even a small number of particle emissions. It could be shown that about 30 % less particles are emitted by the vehicle, when using the novel multi-disk brake instead of the conventional brake. The highest TRWP emissions were collected during acceleration and harsh braking. Characterization of the collected particles using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) revealed diverse particle shapes and differences between particles generated on the dynamometer and on a test track.

Evaluation of the effect of self-assembling peptide and fluoride varnish, alone or in combination with laser irradiation, on artificial enamel caries: a SEM/EDS and Micro-CT study.

OBJECTIVE: The aim of this study was to investigate the effect of remineralization agents such as fluoride varnish and P11-4, alone and in combination with Er: YAG laser, on in-vitro hard tissue repair in artificial enamel lesions. MATERIALS AND METHODS: A total of sixty enamel surfaces of 4 × 5 mm in size were created on both the buccal and lingual sides of thirty extracted wisdom teeth. Remineralization agents were applied to the specimens that were grouped as follows: Group 1, control; Group 2, fluoride varnish (FV); Group 3, P11-4; Group 4, laser; Group 5, laser + FV; and Group 6, laser + P11-4. The fluorescence level was determined with DiagnoDent. The enamel mineral density, area and volume, and caries lesion area and volume were determined with micro-computed tomography (µCT), surface features were evaluated using scanning electron microscopy (SEM), and elemental analysis was performed using energy dispersive x-ray spectroscopy (EDS) . RESULTS: For specimens treated only with self-assembling peptide P11-4, the caries lesion area (mm2) values were 38.19 and 21.62, and the caries lesion volume (mm3) values were 6.27 and 2.99, respectively for pre- and post-treatment. In combination usage of self-assembling peptide P11-4 and laser, the caries lesion area (mm2) values were 38.39 and 16.91, and the caries lesion volume (mm3) values were 11.15 and 3.64, respectively for pre- and post-treatment. In the application of the P11-4 alone and in combination with laser, there was a statistically significant decrease in DiagnoDent values, an increase in enamel volume(mm3),enamel area(mm2) and mineral density(g/cm3) values and a decrease in caries lesion volume(mm3) and area(mm2) obtained by µCT, and an increase in %Ca and %F values obtained by SEM/EDS analysis (p < 0.05). It was discovered that the samples treated with P11-4 had a considerably higher rise in the Ca/P ratio than the samples treated with FV (p < 0.05). The calcium content increased significantly more when P11-4 application was combined with laser irradiation (p < 0.05). CONCLUSIONS: The combined use of self-assembling peptide P11-4 and laser accelerated the remineralization process and increased the remineralization capacity. CLINICAL RELEVANCE: FV and P11-4, alone or in combination with laser, can be successfully used as remineralization agents in initial enamel caries.

Direct Identification of O─O Bond Formation Through Three-Step Oxidation During Water Splitting by Operando Soft X-ray Absorption Spectroscopy.

Anionic redox allows the direct formation of O─O bonds from lattice oxygens and provides higher catalytic in the oxygen evolution reaction (OER) than does the conventional metal ion mechanism. While previous theories have predicted and experiments have suggested the possible O─O bond, it has not yet been directly observed in the OER process. In this study, operando soft X-ray absorption spectroscopy (sXAS) at the O K-edge and the operando Raman spectra is performed on layered double CoFe hydroxides (LDHs) after intercalation with [Cr(C2O4)3]3-, and revealed a three-step oxidation process, staring from Co2+ to Co3+, further to Co4+ (3d6L), and ultimately leading to the formation of O─O bonds and O2 evolution above a threshold voltage (1.4 V). In contrast, a gradual oxidation of Fe is observed in CoFe LDHs. The OER activity exhibits a significant enhancement, with the overpotential decreasing from 300 to 248 mV at 10 mA cm-2, following the intercalation of [Cr(C2O4)3]3- into CoFe LDHs, underscoring a crucial role of anionic redox in facilitating water splitting.

Identifying Sample Provenance From SEM/EDS Automated Particle Analysis via Few-Shot Learning Coupled With Similarity Graph Clustering.

Automated particle analysis (APA) provides a vast amount of compositional data via energy-dispersive X-ray spectroscopy along with size and shape data via scanning electron microscopy for individual particles in a sample. In many instances, APA data are leveraged to support identification of the source of a sample based on the detection of particles of a specific composition. Often, the particles that provide context make up a minuscule portion of the sample. Additionally, the interpretation of complex samples can be difficult due to the diversity of compositions both in the mixture and within a particle. In this work, we demonstrate a method to compute and cluster similarity graphs that describe inter-particle relationships within a sample using a multi-modal few-shot learning neural network. As a proof-of-concept, we show that samples known to have been exposed to gunshot residue can be distinguished from samples occasionally mistaken for gunshot residue. Our workflow builds upon standard APA techniques and data processing methods to unveil additional information in a readily interpretable and quantitatively comparable format.

Cr(VI) removal performance from wastewater by microflora isolated from tannery effluents in a semi-arid environment: a SEM, EDX, FTIR and zeta potential study.

Hexavalent chromium removal from the environment remains a crucial worldwide challenge. To address this issue, microbiological approaches are amongst the straightforward strategies that rely mainly on the bacteria's and fungi's survival mechanisms upon exposure to toxic metals, such as reduction, efflux system, uptake, and biosorption. In this work, scanning electron microscopy, energy-dispersive X-ray spectrophotometry, Fourier transform infrared spectroscopy, and zeta potential measurements were used to investigate the ability of chromium adsorption by Bacillus licheniformis, Bacillus megaterium, Byssochlamys sp., and Candida maltosa strains isolated from tannery wastewater. Scanning electron microscopy combined with energy dispersive X-ray spectroscopy revealed alterations in the cells treated with hexavalent chromium. When exposed to 50 mg/L Cr6+, Bacillus licheniformis and Candida maltosa cells become rough, extracellular secretions are reduced in Bacillus megaterium, and Byssochlamys sp. cells are tightly bound and exhibit the greatest Cr weight percentage. In-depth analysis of Fourier transform infrared spectra of control and Cr-treated cells unveiled Cr-microbial interactions involving proteins, lipids, amino acids, and carbohydrates. These findings were supported by zeta potential measurements highlighting significant variations in charge after treatment with Cr(VI) with an adsorption limit of 100 mg/L Cr6+ for all the strains. Byssochlamys sp. showed the best performance in Cr adsorption, making it the most promising candidate for treating Cr-laden wastewater.

Oxidizing Role of Cu Cocatalysts in Unassisted Photocatalytic CO2 Reduction Using p-GaN/Al2O3/Au/Cu Heterostructures.

Photocatalytic CO2 reduction to CO under unassisted (unbiased) conditions was recently demonstrated using heterostructure catalysts that combine p-type GaN with plasmonic Au nanoparticles and Cu nanoparticles as cocatalysts (p-GaN/Al2O3/Au/Cu). Here, we investigate the mechanistic role of Cu in p-GaN/Al2O3/Au/Cu under unassisted photocatalytic operating conditions using Cu K-edge X-ray absorption spectroscopy and first-principles calculations. Upon exposure to gas-phase CO2 and H2O vapor reaction conditions, the composition of the Cu nanoparticles is identified as a mixture of CuI and CuII oxide, hydroxide, and carbonate compounds without metallic Cu. These composition changes, indicating oxidative conditions, are rationalized by bulk Pourbaix thermodynamics. Under photocatalytic operating conditions with visible light excitation of the plasmonic Au nanoparticles, further oxidation of CuI to CuII is observed, indicating light-driven hole transfer from Au-to-Cu. This observation is supported by the calculated band alignments of the oxidized Cu compositions with plasmonic Au particles, where light-driven hole transfer from Au-to-Cu is found to be thermodynamically favored. These findings demonstrate that under unassisted (unbiased) gas-phase reaction conditions, Cu is found in carbonate-rich oxidized compositions rather than metallic Cu. These species then act as the active cocatalyst and play an oxidative rather than a reductive role in catalysis when coupled with plasmonic Au particles for light absorption, possibly opening an additional channel for water oxidation in this system.

The Combined ICP-MS, ESEM-EDX, and HAADF-STEM-EDX Approach for the Assessment of Metal Sub-Micro- and Nanoparticles in Wheat Grain.

Metal sub-microparticles (SMPs) and nanoparticles (NPs) presence in food is attributable to increasing pollution from the environment in raw materials and finished products. In the present study, a multifaceted analytical strategy based on Environmental Scanning Electron Microscopy and High-Angle Annular Dark-Field-Scanning Transmission Electron Microscopy coupled with Energy-Dispersive X-ray Spectroscopy (ESEM-EDX, HAADF-STEM-EDX) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was proposed for the detection and characterization of metal and metal-containing SMPs and NPs in durum wheat samples, covering a size measurement range from 1 nm to multiple µm. ESEM-EDX and ICP-MS techniques were applied for the assessment of SMP and NP contamination on the surface of wheat grains collected from seven geographical areas characterized by different natural and anthropic conditions, namely Italy, the USA, Australia, Slovakia, Mexico, Austria, and Russia. ICP-MS showed significant differences among the mean concentration levels of metals, with the USA and Italy having the highest level. ESEM-EDX analysis confirmed ICP-MS concentration measurements and measured the highest presence of particles < 0.8 µm in size in samples from Italy, followed by the USA. Less marked differences were observed when particles < 0.15 µm were considered. HAADF-STEM-EDX was applied to a selected number of samples for a preliminary assessment of internal contamination by metal SMPs and NPs, and to expand the measurable particle size range. The multifaceted approach provided similar results for Fe-containing SMPs and NPs. ICP-MS and ESEM-EDX also highlighted the presence of a significant abundance of Ti- and Al-containing particles, while for STEM-EDX, sample preparation artifacts complicated the interpretation. Finally, HAADF-STEM-EDX results provided relevant information about particles in the low nm range, since, by applying this technique, no particles smaller than 50 nm were observed in accordance with ESEM-EDX.

Spectroscopic evidence of spin-state excitation in d-electron correlated semiconductor FeSb2.

Iron antimonide (FeSb2) has been investigated for decades due to its puzzling electronic properties. It undergoes the temperature-controlled transition from an insulator to an ill-defined metal, with a cross-over from diamagnetism to paramagnetism. Extensive efforts have been made to uncover the underlying mechanism, but a consensus has yet to be reached. While macroscopic transport and magnetic measurements can be explained by different theoretical proposals, the essential spectroscopic evidence required to distinguish the physical origin is missing. In this paper, through the use of X-ray absorption spectroscopy and atomic multiplet simulations, we have observed the mixed spin states of 3d 6 configuration in FeSb2. Furthermore, we reveal that the enhancement of the conductivity, whether induced by temperature or doping, is characterized by populating the high-spin state from the low-spin state. Our work constitutes vital spectroscopic evidence that the electrical/magnetical transition in FeSb2 is directly associated with the spin-state excitation.

Tailoring barrier layers design for haute couture through X-ray microanalysis: Insights and guidelines.

Barrier layers against intermetallic diffusion are a fundamental part on engineering electroplated coatings as they improve the lifetime of goods reducing wastes and improving the sustainability of the production chain. This study aims to set a cost-effective methodology to characterize barrier systems by evaluating the effectiveness with a recent approach based on XRF and EDS and characterize the kinetic of diffusion processes with X-ray diffractometry. Several high fashion barrier systems were tested highlighting that anticorrosion systems are not automatically suited as barrier layers for intermetallic diffusion, as opposed to industrial practice. Investigations on gold coatings obtained varying the current density revealed a correlation between the activation energy of the diffusion process, roughness, and crystallite size.

Interrogation of 3d Transition Bimetallic Nanocrystal Nucleation and Growth Using In Situ Electron Microscope and Synchrotron X-ray Techniques.

Understanding the nucleation and growth mechanism of 3d transition bimetallic nanocrystals (NCs) is crucial to developing NCs with tailored nanostructures and properties. However, it remains a significant challenge due to the complexity of 3d bimetallic NCs formation and their sensitivity to oxygen. Here, by combining in situ electron microscopy and synchrotron X-ray techniques, we elucidate the nucleation and growth pathways of Fe-Ni NCs. Interestingly, the formation of Fe-Ni NCs emerges from the assimilation of Fe into Ni clusters together with the reduction of Fe-Ni oxides. Subsequently, these NCs undergo solid-state phase transitions, resulting in two distinct solid solutions, ultimately dominated by γ-Fe3Ni2. Furthermore, we deconvolve the interplays between local coordination and electronic state concerning the growth temperature. We directly visualize the oxidation-state distributions of Fe and Ni at the nanoscale and investigate their changes. This work may reshape and enhance the understanding of nucleation and growth in atomic crystallization.

Biocorrosion and Cytotoxicity Studies on Biodegradable Mg-Based Multicomponent Alloys.

Magnesium-based multicomponent alloys with different compositions, namely Mg60Al20Zn5Cu10Mn5 (Mg60 alloy), Mg70Al15Zn5Cu5Mn5 (Mg70 alloy), and Mg80Al5Cu5Mn5Zn5 (Mg 80) alloys, were prepared using the disintegrated melt deposition technique. The DMD technique is a distinctive method that merges the benefits from gravity die casting and spray forming. This approach facilitates high solidification rates, process yields, and reduced metal wastage, resulting in materials with a fine microstructure and minimal porosity. Their potential as biodegradable materials was assessed through corrosion in different simulated body fluids (SBFs), microstructure, and cytotoxicity tests. It was observed that the Mg60 alloy exhibited low corrosion rates (~× 10-5 mm/year) in all SBF solutions, with a minor amount of corrosive products, and cracks were observed. This can be attributed to the formation of the Mg32(AlZn)49 phase and to its stability due to Mg(OH)2 film, leading to excellent corrosion resistance when compared to the Mg70 and M80 alloys. Conversely, the Mg80 alloy exhibited high corrosion rates, along with more surface degradation and cracks, due to active intermetallic phases, such as Al6Mn, Al2CuMg, and Al2Cu phases. The order of corrosion resistance for the Mg alloy was found to be ASS > HBSS > ABP > PBS. Further, in vitro cytotoxicity studies were carried out using MDA-MB-231 tumor cells. By comparing all three alloys, in terms of proliferation and vitality, the Mg80 alloy emerged as a promising material for implants, with potential antitumor activity.

A Study on the correlation of the physico-chemical properties of Gunshot Residue (GSR) particles with distance using a 9×19 mm Indian ammunition.

The trio elements found in Gunshot Residue (GSR) are considered the key elements that are characteristic of GSR. To date, most forensic laboratories have mainly concentrated on employing carbon stubs analyzed by Scanning Electron Microscopy (SEM) coupled with Energy Dispersive Spectroscopy (EDS) to find IGSR on the hands and clothing of a person. A little elevated from the normal practice, this work is focused on the evaluation of compositional and morphological variations of GSR collected from muzzle end, trajectory, and target obtained by firing the ammunition of choice (9×19 mm Indian ammunition). Even though there may be variations in IGSR compositions within various locations of a weapon, this hasn't been investigated or documented up to this point. To ascertain whether it is possible to identify any variation in GSR particles gathered from these three different locations, the objective of this study is to investigate the structural characteristics and elemental composition of GSR to identify the distinctive parameters that allow for comparison and to establish the composition of the primer. The study also focuses on assessing any possible surface modification that may occur to GSR upon striking the target and establishing a correlation between GSR particles and propellant powder. The collected GSR samples were analyzed using a digital microscope, SEM/EDS, and EDXRF. It was discovered that the primer type showed a strong correlation to the elemental composition and morphology of GSR. By analyzing the GSR particles collected from the various sites as mentioned above, it was possible to identify the primer mixture used in the ammunition and its diversity in elemental concentration. The obtained GSR samples were not spherical but showed an elongated structure and possessed a diameter ranging from 695.4 µm-1.640 mm, 536.2 µm-1.412 mm, and 775.8 µm-1.772 mm respectively. However, the morphology and the size distribution of the particles collected from all three different points showed slight deviation as moving from ME towards TG. The obtained results could identify the primer mixture and diversity in its elemental concentration. The morphology and size distribution of GSR collected from three different points showed deviations.