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1.
Sci Total Environ ; 930: 172765, 2024 Jun 20.
Article in English | MEDLINE | ID: mdl-38692323

ABSTRACT

The presence of contaminated sites/soils in or near cities can pose significant risks to public health. The city of Viviez (France) was taken in reference site bears significant industrial responsibility, particularly in zinc metallurgy, with the presence of a now rehabilitated smelter. This has led to soil contamination by zinc (Zn), lead (Pb), arsenic (As), and cadmium (Cd), with concentrations reaching up to 4856 mg kg-1, 1739 mg kg-1, 195 mg kg-1, and 110 mg kg-1, respectively. The aim of this study is to comprehend the contamination patterns of the site post-rehabilitation, the geochemical behavior of each element, and their speciation (analyzed through BCR, XRD, and XANES) in relation to associated health risks due to metals accessibility for oral ingestion and inhalation by the local population. The findings revealed that elements inducing health risks were not necessarily those with the highest metal contents. All results are discussed in terms of the relationship between element speciation, stability of bearing phases, and their behavior in different media. XANES is an important tool to determine and estimate the Pb-bearing phases in garden soils, as well as the As speciation, which consist of Pb-goethite, anglesite, and Pb-humate, with variations in proportions (the main phases being 66 %, 12 % and 22 % for Pb-goethite, anglesite, and Pb-humate, respectively) whereas As-bearing phase are As(V)-rich ferrihydrite-like. A new aspect lies in the detailed characterization of solid phases before and after bioaccessibility tests, to qualify and quantify the bearing phases involved in the mobility of metallic elements to understand the bioaccessibility behavior. Ultimately, the health risk associated with exposure to inhabitants, in terms of particle ingestion and inhalation, was assessed. Only ingestion-related risk was deemed unacceptable due to the levels of As and Pb.


Subject(s)
Environmental Monitoring , Soil Pollutants , Soil Pollutants/analysis , France , Humans , Arsenic/analysis , Synchrotrons , Lung , Lead/analysis , Zinc/analysis , Metals, Heavy/analysis , Biological Availability , Risk Assessment , Cadmium/analysis , Soil/chemistry
2.
Phys Med Biol ; 69(11)2024 May 30.
Article in English | MEDLINE | ID: mdl-38718813

ABSTRACT

Objective.This study aims to characterize radiological properties of selected additive manufacturing (AM) materials utilizing both material extrusion and vat photopolymerization technologies. Monochromatic synchrotron x-ray images and synchrotron treatment beam dosimetry were acquired at the hutch 3B and 2B of the Australian Synchrotron-Imaging and Medical Beamline.Approach.Eight energies from 30 keV up to 65 keV were used to acquire the attenuation coefficients of the AM materials. Comparison of theoretical, and experimental attenuation data of AM materials and standard solid water for MV linac was performed. Broad-beam dosimetry experiment through attenuated dose measurement and a Geant4 Monte Carlo simulation were done for the studied materials to investigate its attenuation properties specific for a 4 tesla wiggler field with varying synchrotron radiation beam qualities.Main results.Polylactic acid (PLA) plus matches attenuation coefficients of both soft tissue and brain tissue, while acrylonitrile butadiene styrene, Acrylonitrile styrene acrylate, and Draft resin have close equivalence to adipose tissue. Lastly, PLA, co-polyester plus, thermoplastic polyurethane, and White resins are promising substitute materials for breast tissue. For broad-beam experiment and simulation, many of the studied materials were able to simulate RMI457 Solid Water and bolus within ±10% for the three synchrotron beam qualities. These results are useful in fabricating phantoms for synchrotron and other related medical radiation applications such as orthovoltage treatments.Significance and conclusion.These 3D printing materials were studied as potential substitutes for selected tissues such as breast tissue, adipose tissue, soft-tissue, and brain tissue useful in fabricating 3D printed phantoms for synchrotron imaging, therapy, and orthovoltage applications. Fabricating customizable heterogeneous anthropomorphic phantoms (e.g. breast, head, thorax) and pre-clinical animal phantoms (e.g. rodents, canine) for synchrotron imaging and radiotherapy using AM can be done based on the results of this study.


Subject(s)
Synchrotrons , Australia , Monte Carlo Method , Radiotherapy/instrumentation , Radiotherapy/methods , Radiometry/instrumentation , Radiometry/methods , Humans
3.
Int J Periodontics Restorative Dent ; 44(3): 1-10, 2024 May 24.
Article in English | MEDLINE | ID: mdl-38787708

ABSTRACT

This study aimed to investigate the dimensional stability and quality of the alveolar ridge augmented using a synthetic bone block (SBB) at damaged extraction sockets. Four participants were included, and socket augmentation was performed using SBB and a collagen membrane. Intraoral and CBCT scans were performed before extraction (baseline), immediately postoperative (IP), and at 6 months postoperative (6M). At 6M, a trephine biopsy sample was obtained during implant placement, and the sample was observed using synchrotron. Soft tissue profile changes were assessed using profilometric analysis of the intraoral scan data, while dimensional changes in hard tissue were evaluated based on CBCT measurements. Bone quality was analyzed using synchrotron imaging. There were minimal changes in the soft tissue profile between baseline and IP, baseline and 6M, and IP and 6M (0.11 ± 1.08 mm3, 0.02 ± 0.8 mm3, and -0.65 ± 0.82 mm3, respectively). Horizontal bone width was measured at 1-mm increments from the augmented bone crest to 5 mm apically and revealed only a slight reduction (< 1 mm) at all levels between IP and 6M. The augmented bone height was well maintained from IP until 6M (-0.21 ± 0.53 mm). Synchrotron analysis revealed low to moderate bone quality after 6M (percentage of new bone: 16.49% ± 4.91%). Socket augmentation using SBB appears to be a viable technique for regenerating damaged extraction sockets, with the augmented ridge dimensions maintained up to 6M. Further long-term randomized clinical trials are needed.


Subject(s)
Alveolar Ridge Augmentation , Cone-Beam Computed Tomography , Synchrotrons , Tooth Socket , Humans , Tooth Socket/surgery , Tooth Socket/diagnostic imaging , Pilot Projects , Alveolar Ridge Augmentation/methods , Middle Aged , Male , Female , Tooth Extraction , Dental Implantation, Endosseous/methods , Adult , Bone Substitutes/therapeutic use , Aged , Collagen/therapeutic use
4.
Sci Rep ; 14(1): 11973, 2024 05 25.
Article in English | MEDLINE | ID: mdl-38796617

ABSTRACT

The biology underlying proton minibeam radiation therapy (pMBRT) is not fully understood. Here we aim to elucidate the biological effects of pMBRT using Fourier Transform Infrared Microspectroscopy (FTIRM). In vitro (CTX-TNA2 astrocytes and F98 glioma rat cell lines) and in vivo (healthy and F98-bearing Fischer rats) irradiations were conducted, with conventional proton radiotherapy and pMBRT. FTIRM measurements were performed at ALBA Synchrotron, and multivariate data analysis methods were employed to assess spectral differences between irradiation configurations and doses. For astrocytes, the spectral regions related to proteins and nucleic acids were highly affected by conventional irradiations and the high-dose regions of pMBRT, suggesting important modifications on these biomolecules. For glioma, pMBRT had a great effect on the nucleic acids and carbohydrates. In animals, conventional radiotherapy had a remarkable impact on the proteins and nucleic acids of healthy rats; analysis of tumour regions in glioma-bearing rats suggested major nucleic acid modifications due to pMBRT.


Subject(s)
Glioma , Proton Therapy , Rats, Inbred F344 , Synchrotrons , Animals , Rats , Glioma/radiotherapy , Glioma/pathology , Spectroscopy, Fourier Transform Infrared/methods , Cell Line, Tumor , Astrocytes/radiation effects , Astrocytes/metabolism , Nucleic Acids/radiation effects , Brain Neoplasms/radiotherapy , Brain Neoplasms/pathology , Brain Neoplasms/metabolism
5.
PLoS One ; 19(4): e0302009, 2024.
Article in English | MEDLINE | ID: mdl-38620042

ABSTRACT

Phytoliths of biogenic silica play a vital role in the silicon biogeochemical cycle and occlude a fraction of organic carbon. The location, chemical speciation, and quantification of this carbon within phytoliths have remained elusive due to limited direct experimental evidence. In this work, phytoliths (bilobate morphotype) from the sugarcane stalk epidermis are sectioned with a focused ion beam to produce lamellas (≈10 × 10 µm2 size, <500 nm thickness) and probed by synchrotron scanning transmission X-ray microspectroscopy (≈100-200 nm pixel size; energies near the silicon and carbon K-absorption edges). Analysis of the spectral image stacks reveals the complementarity of the silica and carbon spatial distributions, with carbon found at the borders of the lamellas, in islands within the silica, and dispersed in extended regions that can be described as a mixed silica-carbonaceous matrix. Carbon spectra are assigned mainly to lignin-like compounds as well as to proteins. Carbon contents of 3-14 wt.% are estimated from the spectral maps of four distinct phytolith lamellas. The results provide unprecedented spatial and chemical information on the carbon in phytoliths obtained without interference from wet-chemical digestion.


Subject(s)
Silicon Dioxide , Silicon , Silicon Dioxide/chemistry , X-Rays , Carbon/analysis , Synchrotrons
6.
Metallomics ; 16(5)2024 May 02.
Article in English | MEDLINE | ID: mdl-38664065

ABSTRACT

Mercury is a well-recognized environmental contaminant and neurotoxin, having been associated with a number of deleterious neurological conditions including neurodegenerative diseases, such as Alzheimer's disease. To investigate how mercury and other metals behave in the brain, we used synchrotron micro-X-ray fluorescence to map the distribution pattern and quantify concentrations of metals in human brain. Brain tissue was provided by the Rush Alzheimer's Disease Center and samples originated from individuals diagnosed with Alzheimer's disease and without cognitive impairment. Data were collected at the 2-ID-E beamline at the Advanced Photon Source at Argonne National Laboratory with an incident beam energy of 13 keV. Course scans were performed at low resolution to determine gross tissue features, after which smaller regions were selected to image at higher resolution. The findings revealed (1) the existence of mercury particles in the brain samples of two subjects; (2) co-localization and linear correlation of mercury and selenium in all particles; (3) co-localization of these particles with zinc structures; and (4) association with sulfur in some of these particles. These results suggest that selenium and sulfur may play protective roles against mercury in the brain, potentially binding with the metal to reduce the induced toxicity, although at different affinities. Our findings call for further studies to investigate the relationship between mercury, selenium, and sulfur, as well as the potential implications in Alzheimer's disease and related dementias.


Subject(s)
Alzheimer Disease , Brain , Mercury , Selenium , Spectrometry, X-Ray Emission , Synchrotrons , Humans , Mercury/analysis , Mercury/metabolism , Selenium/analysis , Selenium/metabolism , Brain/metabolism , Spectrometry, X-Ray Emission/methods , Alzheimer Disease/metabolism , Aged , Male , Female , Zinc/analysis , Zinc/metabolism
7.
Acta Biomater ; 181: 263-271, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38677636

ABSTRACT

The remarkable damage-tolerance of enamel has been attributed to its hierarchical microstructure and the organized bands of decussated rods. A thorough characterization of the microscale rod evolution within the enamel is needed to elucidate this complex structure. While prior efforts in this area have made use of single particle tracking to track a single rod evolution to various degrees of success, such a process can be both computationally and labor intensive, limited to the evolution path of a single rod, and is therefore prone to error from potentially tracking outliers. Particle image velocimetry (PIV) is a well-established algorithm to derive field information from image sequences for processes that are time-dependent, such as fluid flows and structural deformation. In this work, we demonstrate the use of PIV in extracting the full-field microstructural distribution of rods within the enamel. Enamel samples from a wild African lion were analyzed using high-energy synchrotron X-ray micro-tomography. Results from the PIV analysis provide sufficient full-field information to reconstruct the growth of individual rods that can potentially enable rapid analysis of complex microstructures from high resolution synchrotron datasets. Such information can serve as a template for designing damage-tolerant bioinspired structures for advanced manufacturing. STATEMENT OF SIGNIFICANCE: Thorough characterization and analysis of biological microstructures (viz. dental enamel) allows us to understand the basis of their excellent mechanical properties. Prior efforts have successfully replicated these microstructures via single particle tracking, but the process is computationally and labor intensive. In this work, optical flow imaging algorithms were used to extract full-field microstructural distribution of enamel rods from synchrotron X-ray computed tomography datasets, and a field method was used to reconstruct the growth of individual rods. Such high throughput information allows for the rapid production/prototyping and advanced manufacturing of damage-tolerant bioinspired structures for specific engineering applications. Furthermore, the algorithms used herein are freely available and open source to broaden the availability of the proposed workflow to the general scientific community.


Subject(s)
Dental Enamel , Synchrotrons , Dental Enamel/chemistry , Dental Enamel/diagnostic imaging , Animals , X-Ray Microtomography , Rheology , Optical Imaging/methods
8.
J Synchrotron Radiat ; 31(Pt 3): 566-577, 2024 May 01.
Article in English | MEDLINE | ID: mdl-38682274

ABSTRACT

Improving the scalability of tissue imaging throughput with bright, coherent X-rays requires identifying and mitigating artifacts resulting from the interactions between X-rays and matter. At synchrotron sources, long-term imaging of soft tissues in solution can result in gas bubble formation or cavitation, which dramatically compromises image quality and integrity of the samples. By combining in-line phase-contrast imaging with gas chromatography in real time, we were able to track the onset and evolution of high-energy X-ray-induced gas bubbles in ethanol-embedded soft tissue samples for tens of minutes (two to three times the typical scan times). We demonstrate quantitatively that vacuum degassing of the sample during preparation can significantly delay bubble formation, offering up to a twofold improvement in dose tolerance, depending on the tissue type. However, once nucleated, bubble growth is faster in degassed than undegassed samples, indicating their distinct metastable states at bubble onset. Gas chromatography analysis shows increased solvent vaporization concurrent with bubble formation, yet the quantities of dissolved gasses remain unchanged. By coupling features extracted from the radiographs with computational analysis of bubble characteristics, we uncover dose-controlled kinetics and nucleation site-specific growth. These hallmark signatures provide quantitative constraints on the driving mechanisms of bubble formation and growth. Overall, the observations highlight bubble formation as a critical yet often overlooked hurdle in upscaling X-ray imaging for biological tissues and soft materials and we offer an empirical foundation for their understanding and imaging protocol optimization. More importantly, our approaches establish a top-down scheme to decipher the complex, multiscale radiation-matter interactions in these applications.


Subject(s)
Synchrotrons , X-Rays , Animals , Gases/chemistry , Chromatography, Gas/methods , Ethanol/chemistry
9.
Phys Med Biol ; 69(10)2024 May 09.
Article in English | MEDLINE | ID: mdl-38640914

ABSTRACT

Objective.Magnetic nanoparticles can be used as a targeted delivery vehicle for genetic therapies. Understanding how they can be manipulated within the complex environment of live airways is key to their application to cystic fibrosis and other respiratory diseases.Approach.Dark-field x-ray imaging provides sensitivity to scattering information, and allows the presence of structures smaller than the detector pixel size to be detected. In this study, ultra-fast directional dark-field synchrotron x-ray imaging was utlilised to understand how magnetic nanoparticles move within a live, anaesthetised, rat airway under the influence of static and moving magnetic fields.Main results.Magnetic nanoparticles emerging from an indwelling tracheal cannula were detectable during delivery, with dark-field imaging increasing the signal-to-noise ratio of this event by 3.5 times compared to the x-ray transmission signal. Particle movement as well as particle retention was evident. Dynamic magnetic fields could manipulate the magnetic particlesin situ. Significance.This is the first evidence of the effectiveness ofin vivodark-field imaging operating at these spatial and temporal resolutions, used to detect magnetic nanoparticles. These findings provide the basis for further development toward the effective use of magnetic nanoparticles, and advance their potential as an effective delivery vehicle for genetic agents in the airways of live organisms.


Subject(s)
Gene Transfer Techniques , Animals , Rats , Time Factors , Magnetic Fields , Trachea/diagnostic imaging , Magnetite Nanoparticles/chemistry , X-Rays , Synchrotrons
10.
Acta Crystallogr D Struct Biol ; 80(Pt 4): 279-288, 2024 Apr 01.
Article in English | MEDLINE | ID: mdl-38488731

ABSTRACT

A considerable bottleneck in serial crystallography at XFEL and synchrotron sources is the efficient production of large quantities of homogenous, well diffracting microcrystals. Efficient high-throughput screening of batch-grown microcrystals and the determination of ground-state structures from different conditions is thus of considerable value in the early stages of a project. Here, a highly sample-efficient methodology to measure serial crystallography data from microcrystals by raster scanning within standard in situ 96-well crystallization plates is described. Structures were determined from very small quantities of microcrystal suspension and the results were compared with those from other sample-delivery methods. The analysis of a two-dimensional batch crystallization screen using this method is also described as a useful guide for further optimization and the selection of appropriate conditions for scaling up microcrystallization.


Subject(s)
Synchrotrons , Crystallography, X-Ray , Crystallization/methods , Data Collection
11.
Acta Biomater ; 178: 208-220, 2024 Apr 01.
Article in English | MEDLINE | ID: mdl-38428512

ABSTRACT

The enamel of mammalian teeth is a highly mineralized tissue that must endure a lifetime of cyclic contact and is inspiring the development of next-generation engineering materials. Attempts to implement enamel-inspired structures in synthetic materials have had limited success, largely due to the absence of a detailed understanding of its microstructure. The present work used synchrotron phase-contrast microCT imaging to evaluate the three-dimensional microstructure of enamel from four mammals including Lion, Gray Wolf, Snow Leopard, and Black Bear. Quantitative results of image analysis revealed that the decussation pattern of enamel consists of discrete diazone (D) and parazone (P) bands of rods organized with stacking arrangement of D+/P/D-/P in all mammals evaluated; the D+ and D- refer to distinct diazone bands with juxtaposed rod orientations from the reference plane. Furthermore, the rod orientations in the bands can be described in terms of two principal angles, defined here as the pitch and yaw. While the pitch angle increases from the outer enamel to a maximum (up to ≈ 40°) near the dentin enamel junction, minimal spatial variations are observed in yaw across the enamel thickness. There are clear differences in the decussation parameters of enamel across species that are interpreted here with respect to the structural demands placed on their teeth. The rod pitch and band width of enamel are identified as important design parameters and appear to be correlated with the bite force quotient of the four mammals evaluated. STATEMENT OF SIGNIFICANCE: The multi-functionality of tooth enamel requires both hardness and resistance to fracture, properties that are generally mutually exclusive. Ubiquitous to all mammalian teeth, the enamel is expected to have undergone adaptations in microstructure to accommodate the differences in diet, body size and bite force across animals. For the first time, we compare the complex three-dimensional microstructure of enamel from teeth of multiple mammalian species using synchrotron micro-computed tomography. The findings provide new understanding of the "design" of mammalian enamel microstructures, as well as how specific parameters associated with the decussation of rods appear to be engineered to modulate its fracture resistance.


Subject(s)
Synchrotrons , Tooth , Animals , X-Ray Microtomography , Mammals , Dental Enamel/diagnostic imaging
12.
J Phys Chem Lett ; 15(13): 3478-3485, 2024 Apr 04.
Article in English | MEDLINE | ID: mdl-38513124

ABSTRACT

We propose a novel approach for detecting the binding between proteins making use of the anomalous diffraction of natively present heavy elements, e.g., sulfurs, inside molecular three-dimensional structures. In particular, we analytically and numerically show that the diffraction patterns produced by the anomalous scattering of the sulfur atoms in a given direction depend additively on the relative distances between all couples of sulfur atoms. Thus, the differences in the patterns produced by bound proteins with respect to their nonbonded states can be exploited to rapidly assess protein complex formation. On the basis of our results, we suggest a possible experimental procedure for detecting protein-protein binding. Overall, the completely label-free and rapid method we propose may be readily extended to probe interactions on a large scale, thus paving the way for the development of a novel field of research based on a synchrotron light source.


Subject(s)
Proteins , Synchrotrons , Crystallography, X-Ray , Models, Molecular , Proteins/chemistry , Sulfur/chemistry
13.
BMC Oral Health ; 24(1): 396, 2024 Mar 28.
Article in English | MEDLINE | ID: mdl-38549137

ABSTRACT

BACKGROUND: The stability of implant-abutment connection is crucial to minimize mechanical and biological complications. Therefore, an assessment of the microgap behavior and abutment displacement in different implant-abutment designs was performed. METHODS: Four implant systems were tested, three with a conical implant-abutment connection based on friction fit and a cone angle < 12 ° (Medentika, Medentis, NobelActive) and a system with an angulated connection (< 40°) (Semados). In different static loading conditions (30 N - 90º, 100 N - 90º, 200 N - 30º) the microgap and abutment displacement was evaluated using synchrotron-based microtomography and phase-contrast radioscopy with numerical forward simulation of the optical Fresnel propagation yielding an accuracy down to 0.1 µm. RESULTS: Microgaps were present in all implant systems prior to loading (0.15-9 µm). Values increased with mounting force and angle up to 40.5 µm at an off axis loading of 100 N in a 90° angle. CONCLUSIONS: In contrast to the implant-abutment connection with a large cone angle (45°), the conical connections based on a friction fit (small cone angles with < 12°) demonstrated an abutment displacement which resulted in a deformation of the outer implant wall. The design of the implant-abutment connection seems to be crucial for the force distribution on the implant wall which might influence peri-implant bone stability.


Subject(s)
Dental Implants , Synchrotrons , Humans , Dental Implant-Abutment Design , Computer Simulation , Dental Abutments , Dental Stress Analysis
14.
J Vis Exp ; (205)2024 Mar 08.
Article in English | MEDLINE | ID: mdl-38526130

ABSTRACT

Protocols for robotic protein crystallization using the Crystallization Facility at Harwell and in situ room temperature data collection from crystallization plates at Diamond Light Source beamline VMXi are described. This approach enables high-quality room-temperature crystal structures to be determined from multiple crystals in a straightforward manner and provides very rapid feedback on the results of crystallization trials as well as enabling serial crystallography. The value of room temperature structures in understanding protein structure, ligand binding, and dynamics is becoming increasingly recognized in the structural biology community. This pipeline is accessible to users from all over the world with several available modes of access. Crystallization experiments that are set up can be imaged and viewed remotely with crystals identified automatically using a machine learning tool. Data are measured in a queue-based system with up to 60° rotation datasets from user-selected crystals in a plate. Data from all the crystals within a particular well or sample group are automatically merged using xia2.multiplex with the outputs straightforwardly accessed via a web browser interface.


Subject(s)
Proteins , Synchrotrons , Crystallization/methods , Crystallography, X-Ray , Temperature , Proteins/chemistry , Data Collection
15.
Protein Sci ; 33(4): e4946, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38501481

ABSTRACT

The two major challenges in synchrotron size-exclusion chromatography coupled in-line with small-angle x-ray scattering (SEC-SAXS) experiments are the overlapping peaks in the elution profile and the fouling of radiation-damaged materials on the walls of the sample cell. In recent years, many post-experimental analyses techniques have been developed and applied to extract scattering profiles from these problematic SEC-SAXS data. Here, we present three modes of data collection at the BioSAXS Beamline 4-2 of the Stanford Synchrotron Radiation Lightsource (SSRL BL4-2). The first mode, the High-Resolution mode, enables SEC-SAXS data collection with excellent sample separation and virtually no additional peak broadening from the UHPLC UV detector to the x-ray position by taking advantage of the low system dispersion of the UHPLC. The small bed volume of the analytical SEC column minimizes sample dilution in the column and facilitates data collection at higher sample concentrations with excellent sample economy equal to or even less than that of the conventional equilibrium SAXS method. Radiation damage problems during SEC-SAXS data collection are evaded by additional cleaning of the sample cell after buffer data collection and avoidance of unnecessary exposures through the use of the x-ray shutter control options, allowing sample data collection with a clean sample cell. Therefore, accurate background subtraction can be performed at a level equivalent to the conventional equilibrium SAXS method without requiring baseline correction, thereby leading to more reliable downstream structural analysis and quicker access to new science. The two other data collection modes, the High-Throughput mode and the Co-Flow mode, add agility to the planning and execution of experiments to efficiently achieve the user's scientific objectives at the SSRL BL4-2.


Subject(s)
Synchrotrons , X-Ray Diffraction , Scattering, Small Angle , Chromatography, Gel
16.
Metallomics ; 16(2)2024 02 07.
Article in English | MEDLINE | ID: mdl-38299782

ABSTRACT

Platinum uptake was examined by adding hexachloroplatinate(IV) solution to the unicellular alga Pseudococcomyxa simplex. After the addition of platinum solution ([Pt] = 100 mg/kg, pH 3.2-3.2) for a certain time, the cells were quickly frozen and subjected to µ-XRF (X-ray fluorescence) analysis using synchrotron X-rays. The beam size of approximately 1 micrometer allowed visualization of the platinum distribution within a single cell. On the other hand, we examined platinum uptake in enzyme-treated protoplasts and lyophilized cells and found that the platinum uptake concentrations in these samples were higher than in living in-vivo cells. Cell wall and cell metabolism were presumed to interfere with the uptake of hexachloroplatinate(IV) ions. All platinum ions taken up by the cells were reduced to divalent form. The effect of light on platinum addition was also investigated. When platinum was added under light conditions, some samples showed higher platinum accumulation than under shade conditions.


Subject(s)
Chlorophyta , Platinum , Platinum/pharmacology , Synchrotrons , Chlorophyta/metabolism
17.
Chemosphere ; 353: 141509, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38403125

ABSTRACT

The release of lanthanides (Ln) into the environment has increased in recent decades due to their expanding applications in society. Studying their toxicity in aquatic ecosystems is urgent and challenging, with contradictory evidence presented in the literature. This study compared the biodistribution of La and Gd in Daphnia magna exposed to sub-chronic conditions and developed the first Toxicokinetic-Toxicodynamic (TKTD) model for these lanthanides with this model crustacean. D. magna were initially exposed for 7 days to concentrations close to the LC50 of La (2.10 mg L-1) and Gd (1.70 mg L-1). After exposure, half of the live daphnids were introduced in a clean media to allow depuration over 24 h, while the other organisms were directly prepared for synchrotron imaging measurements. Synchrotron X-ray fluorescence analysis revealed that metal distribution in the organisms was similar for both La and Gd, predominantly localized in the intestinal tract, even after the depuration process. These results indicate that ingested metal can adversely affect organisms under sub-chronic exposure conditions, highlighting the importance of using nominal concentrations as a more suitable indicator of metal bioavailability for risk assessment. The General Unified Threshold Model of Survival (GUTS) TKTD framework, in its reduced form (GUTS-RED), was developed for La and Gd using dissolved and nominal concentrations. D. magna were exposed for 7 days to concentrations from 0.5 to 5 mg L-1 of La or Gd and mortality monitored daily. The mechanistic model revealed a faster toxicokinetics for La than Gd and a higher toxicity for Gd than La in the organism. This study confirmed, despite similar chemical properties, the variation in both toxicity and toxicokinetics between these two metals.


Subject(s)
Lanthanoid Series Elements , Water Pollutants, Chemical , Animals , Daphnia magna , X-Rays , Daphnia , Ecosystem , Synchrotrons , Tissue Distribution , Optical Imaging , Water Pollutants, Chemical/toxicity
18.
Acta Crystallogr D Struct Biol ; 80(Pt 3): 194-202, 2024 Mar 01.
Article in English | MEDLINE | ID: mdl-38411550

ABSTRACT

The combination of X-ray free-electron lasers (XFELs) with serial femtosecond crystallography represents cutting-edge technology in structural biology, allowing the study of enzyme reactions and dynamics in real time through the generation of `molecular movies'. This technology combines short and precise high-energy X-ray exposure to a stream of protein microcrystals. Here, the XFEL structure of carbonic anhydrase II, a ubiquitous enzyme responsible for the interconversion of CO2 and bicarbonate, is reported, and is compared with previously reported NMR and synchrotron X-ray and neutron single-crystal structures.


Subject(s)
Carbonic Anhydrase II , Carbonic Anhydrase II/chemistry , Crystallography, X-Ray , Proteins/chemistry , Synchrotrons , X-Rays , Humans
19.
Commun Biol ; 7(1): 157, 2024 Feb 07.
Article in English | MEDLINE | ID: mdl-38326549

ABSTRACT

The characterization of the vibrations of the middle ear ossicles during sound transmission is a focal point in clinical research. However, the small size of the structures, their micrometer-scale movement, and the deep-seated position of the middle ear within the temporal bone make these types of measurements extremely challenging. In this work, dynamic synchrotron-based X-ray phase-contrast microtomography is used on acoustically stimulated intact human ears, allowing for the three-dimensional visualization of entire human eardrums and ossicular chains in motion. A post-gating algorithm is used to temporally resolve the fast micromotions at 128 Hz, coupled with a high-throughput pipeline to process the large tomographic datasets. Seven ex-vivo fresh-frozen human temporal bones in healthy conditions are studied, and the rigid body motions of the ossicles are quantitatively delineated. Clinically relevant regions of the ossicular chain are tracked in 3D, and the amplitudes of their displacement are computed for two acoustic stimuli.


Subject(s)
Imaging, Three-Dimensional , Synchrotrons , Humans , X-Rays , Ear, Middle/diagnostic imaging , Ear Ossicles/diagnostic imaging
20.
J Am Soc Mass Spectrom ; 35(3): 476-486, 2024 Mar 06.
Article in English | MEDLINE | ID: mdl-38335063

ABSTRACT

Hydroxyl radical protein footprinting (HRPF) using synchrotron X-ray radiation (XFP) and mass spectrometry is a well-validated structural biology method that provides critical insights into macromolecular structural dynamics, such as determining binding sites, measuring affinity, and mapping epitopes. Numerous alternative sources for generating the hydroxyl radicals (•OH) needed for HRPF, such as laser photolysis and plasma irradiation, complement synchrotron-based HRPF, and a recently developed commercially available instrument based on flash lamp photolysis, the FOX system, enables access to laboratory benchtop HRPF. Here, we evaluate performing HRPF experiments in-house with a benchtop FOX instrument compared to synchrotron-based X-ray footprinting at the NSLS-II XFP beamline. Using lactate oxidase (LOx) as a model system, we carried out •OH labeling experiments using both instruments, followed by nanoLC-MS/MS bottom-up peptide mass mapping. Experiments were performed under high glucose concentrations to mimic the highly scavenging conditions present in biological buffers and human clinical samples, where less •OH are available for reaction with the biomolecule(s) of interest. The performance of the FOX and XFP HRPF methods was compared, and we found that tuning the •OH dosage enabled optimal labeling coverage for both setups under physiologically relevant highly scavenging conditions. Our study demonstrates the complementarity of FOX and XFP labeling approaches, demonstrating that benchtop instruments such as the FOX photolysis system can increase both the throughput and the accessibility of the HRPF technique.


Subject(s)
Hydroxyl Radical , Synchrotrons , Humans , X-Rays , Hydroxyl Radical/chemistry , Protein Footprinting/methods , Tandem Mass Spectrometry , Oxidation-Reduction
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