Gadolinium Concentration Research Articles

Erbium doped gadolinium borate glasses for optical communication window applications

The intent of the current work is to synthesize (79-x) B2O3 + 10ZnO+ 10BaO+ xGd2O3 + 1Er2O3 where (x = 0.0, 5.0, 10.0, 15.0, 20.0) glasses with various concentration of gadolinium (III) oxide using conventional melt-quenching technique. The prepared glasses were subjected to spectroscopic analysis for understanding their behaviour in optical and photoluminescence properties. The absorption bands of the prepared samples were investigated using absorption spectroscopy between 300 nm and 1700 nm. The stimulation from ground level 4I15/2 caused significant (Er3+ ions) absorption peaks to develop. The branching ratio, fluorescence full width at half maximum of NIR emission, and lifetime, of I13/2 level have all been assessed together with the Judd-Oflet parameters Ωλ (λ = 2, 4, 6). The absorption and emission cross-sections were assessed using the Judd-Ofelt and McCumber hypothesis. The reported values are sufficiently consistent to be taken into consideration for prospective application in the optical communication windows in C and L bands.

Detection of Endometriosis Lesions Using Gd-Based Collagen I Targeting Probe in Murine Models of Endometriosis

PurposeEndometriosis is a chronic condition characterized by high fibrotic content and affecting about 10% of women during their reproductive years. Yet, no clinically approved agents are available for non-invasive endometriosis detection. The purpose of this study was to investigate the utility of a gadolinium-based collagen type I targeting probe (EP-3533) to non-invasively detect endometriotic lesions using magnetic resonance imaging (MRI). Previously, this probe has been used for detection and staging of fibrotic lesions in the liver, lung, heart, and cancer. In this study we evaluate the potential of EP-3533 for detecting endometriosis in two murine models and compare it with a non-binding isomer (EP-3612).ProceduresFor imaging, we utilized two GFP-expressing murine models of endometriosis (suture model and injection model) injected intravenously with EP3533 or EP-33612. Mice were imaged before and after bolus injection of the probes. The dynamic signal enhancement of MR T1 FLASH images was analyzed, normalized, and quantified, and the relative location of lesions was validated through ex vivo fluorescence imaging. Subsequently, the harvested lesions were stained for collagen, and their gadolinium content was quantified by inductively coupled plasma optical emission spectrometry (ICP-OES).ResultsWe showed that EP-3533 probe increased the signal intensity in T1-weighted images of endometriotic lesions in both models of endometriosis. Such enhancement was not detected in the muscles of the same groups or in endometriotic lesions of mice injected with EP-3612 probe. Consequentially, control tissues had significantly lower gadolinium content, compared to the lesions in experimental groups. Probe accumulation was similar in endometriotic lesions of either model.ConclusionsThis study provides evidence for feasibility of targeting collagen type I in the endometriotic lesions using EP3533 probe. Our future work includes investigation of the utility of this probe for therapeutic delivery in endometriosis to inhibit signaling pathways that cause the disease.

Free-breathing high isotropic resolution quantitative susceptibility mapping (QSM) of liver using 3D multi-echo UTE cones acquisition and respiratory motion-resolved image reconstruction.

To enable free-breathing and high isotropic resolution liver quantitative susceptibility mapping (QSM) using 3D multi-echo UTE cones acquisition and respiratory motion-resolved image reconstruction. Using 3D multi-echo UTE cones MRI, a respiratory motion was estimated from the k-space center of the imaging data. After sorting the k-space data with estimated motion, respiratory motion state-resolved reconstruction was performed for multi-echo data followed by nonlinear least-squares fitting for proton density fat fraction (PDFF), , and fat-corrected B0 field maps. PDFF and B0 field maps were subsequently used for QSM reconstruction. The proposed method was compared with motion-averaged (gridding) reconstruction and conventional 3D multi-echo Cartesian MRI in moving gadolinium phantom and in vivo studies. Region of interest (ROI)-based linear regression analysis was performed on these methods to investigate correlations between gadolinium concentration and QSM in the phantom study and between and QSM in in vivo study. Cones with motion-resolved reconstruction showed sharper image quality compared to motion-averaged reconstruction with a substantial reduction of motion artifacts in both moving phantom and in vivo studies. For ROI-based linear regression analysis of the phantom study, susceptibility values from cones with motion-resolved reconstruction ( = 0.31 0.05, = 0.999) and Cartesian without motion ( = 0.32 0.04, = 1.000) showed linear relationships with gadolinium concentrations and showed good agreement with each other. For in vivo, motion-resolved reconstruction showed higher goodness of fit ( = 0.00261 0.524, = 0.977) compared to motion-averaged reconstruction ( = 0.0021 0.572, = 0.723) in ROI-based linear regression analysis between and QSM. Feasibility of free-breathing liver QSM was demonstrated with motion-resolved 3D multi-echo UTE cones MRI, achieving high isotropic resolution currently unachievable in conventional Cartesian MRI.

CATION-DEFICIENT SODIUM–GADOLINIUM MOLYBDATES OF VARIABLE COMPOSITION. SIMULATION OF THE PROPERTIES AND LOCAL STRUCTURE

Cation-deficient Na2–3xGdxMoO4 solid solutions in the NaGd(MoO4)2–Gd2(MoO4)3 system have been simulated by the interatomic potentials method. The parameters and volume of unit cell, as well as density, bulk modulus, enthalpy, vibrational entropy, and heat capacity in dependence of the composition are determined. Temperature dependences of the heat capacity and vibrational entropy are plotted. The local structure of the solid solutions has been studied. It is shown that the vacancy–oxygen distances are on average 5.0% larger than the Na–O distances and 11.8% larger than the Gd–O distances. The sizes of these coordination polyhedra slightly increase with an increase in the gadolinium content, which is accompanied by an increase in the unit-cell size. The parameter c increases with a higher rate as compared to a, which is indicative of distortion of the unit cell and polyhedra.

Effect of Gd3+ doping on the luminescence and up-conversion of Pr3+ activated Ca2(Lu0.99-xGdxPr0.01)Hf2Al3O12

In this work, the optical properties including the up-conversion of Pr3+ doped Ca2(Lu,Gd) Hf2Al3O12 are presented. The change in optical properties of trivalent praseodymium as a function of the gadolinium concentration was investigated by gradually replacing the lutetium cations by Gd3+. The presence of single-phase samples was proven by PXRD. Additionally, reflection spectroscopy, as well as excitation and emission measurements under X-ray and VUV excitation were recorded. Finally, decay curves were taken to determine the dependence of the decay constants from the chemical composition.

Theranostic RGD@Fe3O4-Au/Gd NPs for the targeted radiotherapy and MR imaging of breast cancer

BackgroundAs a radiosensitizing agent in magnetic resonance imaging (MRI), gadolinium is disadvantageous in that it confers a rather high toxicity and low longitudinal comfort time (r1). We hypothesized that gadolinium when combined with gold-coated iron oxide nanoparticles (NPs), might deliver better radiosensitization in MRI-based cancer theranostics. After being synthesized ligand/receptor RGD@Fe3O4-Au/Gd nanoparticles, they were characterized via some methods, such as visible–ultraviolet spectroscopy (UV–VIS), Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), and transmission electron microscope (TEM). Using relaxometry, the parameters of contrast change in T1-weighted MRI and the rate of radiation sensitivity on cancerous (MCF-7, SK-BR-3 and MDA-MB-231 (and reference (MCF-10a) breast cell lines were investigated.ResultsThe presence of ultra-small iron oxide, gold, gadolinium, and RGD peptide as components of the RGD@Fe3O4-Au/Gd nanocomplex was confirmed by UV–visible, FTIR, EDX and XRD tests. With a size ranging from 4.124 nm (DLS) to 15 nm (TEM), these NPs exhibited a surface charge of –45.7 mV and a magnetic saturation of 3 emu/g. The concentrations of iron, gadolinium and gold samples in the nanocomplex were 1000, 1171 and 400 parts per million (ppm), respectively. In the relaxometry test, the rates of r2/r1 and r1 NPs were 1.56 and 23.5 mM−1 s−1. The dose increase factor for targeted (RGD@Fe3O4-Au/Gd) and non-targeted (Fe3O4-Au/Gd) NPs at 6 MV and 2 Gy was 89.1 and 59.1, respectively.ConclusionOwing to an enhanced signal-to-noise ratio (SNR), as confirmed by the MRI of RGD receptor-expressing MDA-MB-231 cells, RGD@Fe3O4-Au/Gd NPs were found to confer higher radiosensitization and an overall better performance as a novel radiosensitizer for MRI-based breast cancer theranostics than Fe3O4-Au/Gd nanocomplex.Graphical

Cyanobacteria Arthospira platensis as an Effective Tool for Gadolinium Removal from Wastewater

The biosorption and bioaccumulation of gadolinium by Arthospira platensis in batch experiments was examined. In biosorption experiments, the influence of pH, gadolinium concentration, time of contact and temperature on Arthospira platensis sorption capacity was investigated. The maximum biosorption capacity of 101 mg/g was attained at a pH of 3.0 and temperature of 20 °C. A pseudo-first-order model was applicable to describe the kinetics of the biosorption and the Freundlich model to explain the equilibrium of the process. In bioaccumulation experiments, besides the examination of the gadolinium uptake by Arthospira platensis, its effect on biomass productivity as well as the content of proteins, lipids, carbohydrates and pigments was assessed. The addition of gadolinium in the cultivation medium resulted in the increase in biomass productivity and the content of MDA and, at the same time, in the reduction in the amount of proteins and carbohydrates. The content of other monitored parameters did not change significantly. The water extracts obtained from Arthospira platensis showed a higher antiradical activity against the ABTS cation radical in comparison with ethanolic extracts. Arthospira platensis is of interest for the development of the technology of gadolinium-contaminated wastewater remediation.

Impact of Arterial Input Function and Pharmacokinetic Models on DCE-MRI Biomarkers for Detection of Vascular Effect Induced by Stroma-Directed Drug in an Orthotopic Mouse Model of Pancreatic Cancer.

We demonstrated earlier in mouse models of pancreatic ductal adenocarcinoma (PDA) that Ktrans derived from dynamic contrast-enhanced (DCE) MRI detected microvascular effect induced by PEGPH20, a hyaluronidase which removes stromal hyaluronan, leading to reduced interstitial fluid pressure in the tumor (Clinical Cancer Res (2019) 25: 2314-2322). How the choice of pharmacokinetic (PK) model and arterial input function (AIF) may impact DCE-derived markers for detecting such an effect is not known. Retrospective analyses of the DCE-MRI of the orthotopic PDA model are performed to examine the impact of individual versus group AIF combined with Tofts model (TM), extended-Tofts model (ETM), or shutter-speed model (SSM) on the ability to detect the microvascular changes induced by PEGPH20 treatment. Individual AIF exhibit a marked difference in peak gadolinium concentration. However, across all three PK models, kep values show a significant correlation between individual versus group-AIF (p < 0.01). Regardless individual or group AIF, when kep is obtained from fitting the DCE-MRI data using the SSM, kep shows a significant increase after PEGPH20 treatment (p < 0.05 compared to the baseline); %change of kep from baseline to post-treatment is also significantly different between PEGPH20 versus vehicle group (p < 0.05). In comparison, when kep is derived from the TM, only the use of individual AIF leads to a significant increase of kep after PEGPH20 treatment, whereas the %change of kep is not different between PEGPH20 versus vehicle group. Group AIF but not individual AIF allows detection of a significant increase of Vp (derived from the ETM) in PEGPH20 versus vehicle group (p < 0.05). Increase of Vp is consistent with a large increase of mean capillary lumen area estimated from immunostaining. Our results suggest that kep derived from SSM and Vp from ETM, both using group AIF, are optimal for the detection of microvascular changes induced by stroma-directed drug PEGPH20. These analyses provide insights in the choice of PK model and AIF for optimal DCE protocol design in mouse pancreatic cancer models.

Association of dynamic contrast-enhanced MRI and 18F-Fluorodeoxyglucose PET/CT parameters with neoadjuvant therapy response and survival in esophagogastric cancer

IntroductionBetter predictive markers are needed to deliver individualized care for patients with primary esophagogastric cancer. This exploratory study aimed to assess whether pre-treatment imaging parameters from dynamic contrast-enhanced MRI and 18F-fluorodeoxyglucose (18F-FDG) PET/CT are associated with response to neoadjuvant therapy or outcome. Materials and methodsFollowing ethical approval and informed consent, prospective participants underwent dynamic contrast-enhanced MRI and 18F-FDG PET/CT prior to neoadjuvant chemotherapy/chemoradiotherapy ± surgery. Vascular dynamic contrast-enhanced MRI and metabolic 18F-FDG PET parameters were compared by tumor characteristics using Mann Whitney U test and with pathological response (Mandard tumor regression grade), recurrence-free and overall survival using logistic regression modelling, adjusting for predefined clinical variables. Results39 of 47 recruited participants (30 males; median age 65 years, IQR: 54, 72 years) were included in the final analysis. The tumor vascular-metabolic ratio was higher in patients remaining node positive following neoadjuvant therapy (median tumor peak enhancement/SUVmax ratio: 0.052 vs. 0.023, p = 0.02). In multivariable analysis adjusted for age, gender, pre-treatment tumor and nodal stage, peak enhancement (highest gadolinium concentration value prior to contrast washout) was associated with pathological tumor regression grade. The odds of response decreased by 5% for each 0.01 unit increase (OR 0.95; 95% CI: 0.90, 1.00, p = 0.04). No 18F-FDG PET/CT parameters were predictive of pathological tumor response. No relationships between pre-treatment imaging and survival were identified. ConclusionPre-treatment esophagogastric tumor vascular and metabolic parameters may provide additional information in assessing response to neoadjuvant therapy.

Feasibility study of on-line monitoring gadolinium based on neutron induced gamma activation

Gadolinium is a soluble neutron poison for ensuring criticality safety of nuclear facility. A neutron induced gamma activation device was developed for the on-line measurement of gadolinium. The experimental device consisted of an 241Am–Be neutron source, six 3He detectors and a liquid scintillation detector. The size of sample container was optimized by using Monte Carlo simulations. Aqueous sample containing gadolinium nitrate were conducted with the device to obtain the calibration curve, and neutron self-shielding effect was also studied to correct the non-linear response. The results showed the minimum detectable concentration (MDC) of gadolinium was 0.426 mg/L. Two test samples were conducted to evaluate the performance of the device. The results demonstrated that the discrepancies were within 10%, which indicate the developed system can be successfully used for on-line monitoring of gadolinium.

Simultaneous estimation of the cellular water exchange rate, intracellular volume fraction, and longitudinal relaxation rate in cancer cells.

The purpose of the current study was to investigate the feasibility of simultaneously estimating the cellular water efflux rate ( ), intracellular longitudinal relaxation rate ( ), and intracellular volume fraction ( ) of a cell suspension using multiple samples with different gadolinium concentrations. Numerical simulation studies were conducted to assess the uncertainty in the estimation of , , and from saturation recovery data using single (SC) or multiple concentrations (MC) of gadolinium-based contrast agent (GBCA). In vitro experiments with 4 T1 murine breast cancer and SCCVII squamous cell cancer models were conducted at 11 T to compare parameter estimation using the SC protocol with that using the MC protocol. The cell lines were challenged with a Na+ /K+ -ATPase inhibitor, digoxin, to assess the treatment response in terms of , , and . Data analysis was conducted using the two-compartment exchange model for parameter estimation. The simulation study data demonstrate that the MC method, compared with the SC method, reduces the uncertainty of the estimated by decreasing the interquartile ranges from 27.3% ± 3.7% to 18.8% ± 5.1% and the median differences from ground truth from 15.0% ± 6.3% to 7.2% ± 4.2%, while estimating and simultaneously. In the cell studies, the MC method demonstrated reduced uncertainty in overall parameter estimation compared with the SC approach. MC method-measured parameter changes in cells treated with digoxin increased by 11.7% (p = 0.218) and by 5.9% (p = 0.234) for 4 T1 cells, respectively, and decreased by 28.8% (p = 0.226) and by 1.6% (p = 0.751) for SCCVII cells, respectively. did not change noticeably by the treatment. The results of this study substantiate the feasibility of using saturation recovery data of multiple samples with different GBCA concentrations for simultaneous measurement of the cellular water efflux rate, intracellular volume fraction, and intracellular longitudinal relaxation rate in cancer cells.

The influence of gadolinium concentration on the twin propagation rate in magnesium alloys

Ultra-high-speed camera (UHSC) imaging was used for the study of the influence of gadolinium (Gd) content on the longitudinal growth of twins in Mg-Gd binary alloys. The results clearly indicate that the twin propagation rate is of the order of 101 m/s and slows down with increasing Gd concentration. Concurrent molecular dynamics (MD) simulations reveal that the presence of Gd atoms enhances the formation of stacking faults (SFs), which hinder twin propagation as effectively as twin boundary pinning by Gd solutes. As a result, the twin tip exhibits intermittent motion at the microscopic level.

Role of Gd3+ on the magnetocaloric properties of lanthanum-strontium manganite

In this work, the role of magnetic ion Gd3+ in the crystal structure, magnetic and magnetocaloric properties of doped lanthanum-strontium manganite (La0.7-xGdxSr0.3MnO3 varying x from 0 to 0.2) synthesized by high-energy ball milling assisted with annealing, is discussed. Furthermore, the interplay between the magnetic and crystal structure in co-doped manganites is proposed. The X-ray diffraction patterns confirm the complete formation of lanthanum manganite showing different crystal structures regarding the gadolinium content. The Sr2+/Gd3+ doped lanthanum manganites with Gd3+ concentration lower than 0.1 mol show rhombohedral crystal structure (R-3cH). Higher gadolinium concentrations promote a phase transition from rhombohedral to orthorhombic crystal structure. The Curie temperature of the manganites decreases with an increase in Gd3+ content, from 376 K to 257 K, for un-doped and x = 0.2 Gd3+, respectively, attributed to a weakening in the double exchange interaction. Close interaction of the lattice parameters such as bond distances, bond angles, and symmetry-related with the mixed magnetic interactions was observed. The maximum magnetocaloric effect (MCE) calculated using Maxwelĺs ratio was observed around the paramagnetic to ferromagnetic ordering, at 311 K, for gadolinium content of 0.15 mol, measured through the entropy change. The Sr2+/Gd3+ doped lanthanum manganite shows a magnetically induced entropy change (|ΔSM|) in the range from 2.4 to 3.69 Jkg-1K−1 under 18 kOe, for 0.10 and 0.15, respectively, doing this manganite a suitable material for refrigeration applications at room temperature.

Study of microstructure and corrosion resistance of FeCrAl-Gd alloys

The corrosion resistance of Fe–21Cr–4Al alloys with different gadolinium (Gd) contents was investigated by means of microstructure, salt spray corrosion and electrochemical tests. The microstructural analysis shows that Gd and Gd2O3 formed at grain boundaries will pinch the grain boundaries and slow down the grain growth, thus reducing the grain size. The corrosion results showed that as with the increase of the Gd component, there are two competing corrosion mechanisms: 1) the grain size becomes smaller, which makes the corrosion pit difficult to expand; more Gd oxides are formed, which hinders the penetration of Cl−; 2) the number of grain boundaries and dislocations increases, which expedite the corrosion rate; and the increasing Gd-rich phase serve as cathodes for the micro-galvanic corrosion. A minimum corrosion rate of 1.94 mm/year was achieved for the Gd-containing alloy, a reduction of 46.4% compared to the original alloy.

Rapid In Vitro Quantification of a Sensitized Gadolinium Chelate via Photoinduced Triplet Harvesting.

Gadolinium (Gd) based contrast agents (GBCAs) are widely used in magnetic resonance imaging (MRI) and are paramount to cancer diagnostics and tumor pharmacokinetic analysis. Accurate quantification of gadolinium concentration is essential to monitoring the biodistribution, clearance, and pharmacodynamics of GBCAs. However, current methods of quantifying gadolinium in blood or plasma (biological media) are both low throughput and clinically unavailable. Here, we have demonstrated the use of a sensitized gadolinium chelate, Gd[DTPA-cs124], as an MRI contrast agent that can be used to measure the concentration of gadolinium via luminescence quantification in biological media following transmetalation with a terbium salt. Gd[DTPA-cs124] was synthesized by conjugating carbostyril-124 (cs124) to diethylenetriaminepentaacetic acid (DTPA) and chelating to gadolinium. We report increases in both stability and relaxivity compared to the clinically approved analog Gd[DTPA] (gadopentetic acid or Magnevist). In vivo MRI experiments were conducted using C57BL6 mice in order to further illustrate the performance of Gd[DTPA-cs124] as an MRI contrast agent in comparison to Magnevist. Our results indicate that similar chemical modification to existing clinically approved GBCA may likewise provide favorable property changes, with the ability to be used in a gadolinium quantification assay. Furthermore, our assay provides a straightforward and high-throughput method of measuring gadolinium in biological media using a standard laboratory plate reader.

PHARMACOKINETICS OF RARE-EARTH METALS IN THE BODY OF BROILER CHICKENS UNDER THE CONDITIONS OF USING GADOLINIUM AND LANTHANUM ORTHOVANADATE

Currently, the search for substances that will help increase the assimilation of nutrients from the diet continues, and the most promising in this regard are nanoparticles of rare earth metals (REM) – orthovanadates of gadolinium (NP GdVO4:Eu3+) and lanthanum (NP LaVO4:Eu3+), synthesized relatively recently, because they provide optimization of the state of pro-oxidant/antioxidant defense systems and oxygen metabolism and showed an adaptogenic effect on the body of white rats under conditions of food stress. The aim of the work was to investigate the pharmacokinetics of rare earth elements in the body of broiler chickens under the conditions of the use of gadolinium and lanthanum orthovanadates. An experiment was conducted on broiler chickens of the "Сobb-500" cross. According to the principle of analogues, 3 experimental and one control group of day-old broiler chickens (n=30) were formed: the chickens of the I experimental group received a solution of NP GdVO4:Eu3+ for 10 days, the II experimental group received a solution NP LaVO4:Eu3+, III experimental group – a solution of NP GdVO4:Eu3+ and NP LaVO4:Eu3+ (on average, chickens received 0.09 (0.13-0.05) mg/kg of NP body weight). After 10 days, NP administration was stopped and the chickens were observed for another 5 days. For the study, samples of muscle stomach, small and large intestine with contents, liver, lungs, brain, feather with skin, thigh muscles, heart, kidneys were taken. It was established that GdVO4:Eu3+ NPs have greater material accumulation, as evidenced by the content of gadolinium in all the examined organs and tissues, and LaVO4:Eu3+ NPs – functional accumulation, since they are less absorbed in the body (lanthanum was determined to a greater extent in the digestive tract). Along with this, the digestive tract can be considered as a kind of depot of nanoparticles of both species, especially lanthanum, since 5 days after the end of administration, both lanthanum and gadolinium are redistributed in the bird's body. Since the main critical period in growing broilers is the first 2 weeks of life, nanoparticles of gadolinium and lanthanum orthovanadates can be used for 5-10 days to overcome stress and increase the adaptation capabilities of the body.

The problems of increasing the thermoelectric figure of merit of polycrystalline misfit layered compounds on (Gd-=SUB=-x-=/SUB=-Dy-=SUB=-1-x-=/SUB=-S)-=SUB=-z-=/SUB=-NbS-=SUB=-2-=/SUB=- example

The lattice disorder of different architecture and dimensions influence on the thermoelectric properties (Seebeck coefficient S, resistivity rho, total thermal conductivity kappatot,, power factor S2/rho, figure of merit ZT) of the polycrystalline ternary sulfides MTS3 was studied. The high-temperature misfit layered compounds (MS)zNbS2 (MS is GdxDy1-xS solid solutions) were chosen as objects of the study. The variation of gadolinium concentration along the series x=0.0, 0.1, 0.2, 0.5, 1.0 allowed one to alter the short-range and the long-range order of the crystal lattice and to study their effect on thermoelectric parameters of (GdxDy1-xS)zNbS2. At low concentration of x=0.1 the crystallite size increases, cause the deformation stresses decrease and, thereby, leads to an abnormal changes of S, rho, kappatot values and ZT decrease. An increase of the gadolinium concentration (x=0.2-0.5) alters the electronic structure and the interatomic bonding character of the incommensurate subsystems [GdxDy1-xS] and [NbS2]. In this case, S and rho values remains practically unaffected, while the thermal conductivity value decreases by 40% and ZT increases by 2 times. The nature of this phenomenon and the anisotropy of the thermoelectric properties were discussed. Keywords:: misfit layers compounds, thermoelectric properties, lattice disorder, solid solution, crystallite boundaries.

Проблемы увеличения термоэлектрической эффективности поликристаллической керамики несоразмерных слоистых соединений на примере (Gd-=SUB=-x-=/SUB=-Dy-=SUB=-1-x-=/SUB=-S)-=SUB=-z-=/SUB=-NbS-=SUB=-2-=/SUB=-

The lattice disorder of different architecture and dimensions influence on the thermoelectric properties (Seebeck coefficient S, resistivity , total thermal conductivity κtot, power factor S2/, figure of merit ZT) of the polycrystalline ternary sulfides MTS3 was studied. The high-temperature misfit layered compounds (MS)zNbS2 (MS is GdxDy1-xS solid solutions) were chosen as objects of the study. The variation of gadolinium concentration along the series x = 0.0, 0.1, 0.2, 0.5, 1.0 allowed one to alter the short-range and the long-range order of the crystal lattice and to study their effect on thermoelectric parameters of (GdxDy1-xS)zNbS2. At low concentration of x = 0.1 the crystallite size increases, cause the deformation stresses decrease and, thereby, leads to an abnormal changes of S, , κtot values and ZT decrease. An increase of the gadolinium concentration (x = 0.2–0.5) alters the electronic structure and the interatomic bonding character of the incommensurate subsystems (GdxDy1-xS) and NbS2. In this case, S and  values remains practically unaffected, while the thermal conductivity value decreases by 40% and ZT increases by 2 times. The nature of this phenomenon and the anisotropy of the thermoelectric properties were discussed.

AI-AIF: artificial intelligence-based arterial input function for quantitative stress perfusion cardiac magnetic resonance.

One of the major challenges in the quantification of myocardial blood flow (MBF) from stress perfusion cardiac magnetic resonance (CMR) is the estimation of the arterial input function (AIF). This is due to the non-linear relationship between the concentration of gadolinium and the MR signal, which leads to signal saturation. In this work, we show that a deep learning model can be trained to predict the unsaturated AIF from standard images, using the reference dual-sequence acquisition AIFs (DS-AIFs) for training. A 1D U-Net was trained, to take the saturated AIF from the standard images as input and predict the unsaturated AIF, using the data from 201 patients from centre 1 and a test set comprised of both an independent cohort of consecutive patients from centre 1 and an external cohort of patients from centre 2 (n = 44). Fully-automated MBF was compared between the DS-AIF and AI-AIF methods using the Mann-Whitney U test and Bland-Altman analysis. There was no statistical difference between the MBF quantified with the DS-AIF [2.77 mL/min/g (1.08)] and predicted with the AI-AIF (2.79 mL/min/g (1.08), P = 0.33. Bland-Altman analysis shows minimal bias between the DS-AIF and AI-AIF methods for quantitative MBF (bias of -0.11 mL/min/g). Additionally, the MBF diagnosis classification of the AI-AIF matched the DS-AIF in 669/704 (95%) of myocardial segments. Quantification of stress perfusion CMR is feasible with a single-sequence acquisition and a single contrast injection using an AI-based correction of the AIF.

Layered Gadolinium-Europium-Terbium Hydroxides Sensitised with 4-Sulfobenzoate as All Solid-State Luminescent Thermometers

Ternary layered gadolinium-europium-terbium basic chlorides were synthesised using a facile hydrothermal-microwave technique. A continuous series of solid solutions was obtained in a full range of rare earth concentrations. To sensitise the luminescence of Eu3+ and Tb3+, a 4-sulfobenzoate anion was intercalated in the ternary layered rare earth hydroxides using one of two methods—a high-temperature ion exchange or a single-stage synthesis. The luminescent colour of the materials was governed by the gadolinium content: at low and medium gadolinium concentrations (0–70%), layered Gd-Eu-Tb basic sulfobenzoate exhibited a bright red europium luminescence; at high gadolinium content (70–90%), a bright green terbium luminescence was observed. The colour coordinates of layered Gd-Eu-Tb basic sulfobenzoate luminescence depended on the temperature in the physiological range (20–50 °C). The relative thermal sensitivity of the obtained materials was up to 2.9%·K−1.