Synchronous activation of praseodymium vanadate/graphitic carbon nitride nanocomposite: A promising electrode material for detection of flavonoid- Quercetin.

Flavonoids or phenolic compounds are part of the daily intake of every human being. Though they are positive traders for metabolism, excessive intakes bring about detrimental impacts on human health. Herein, the anti-cancer capacitive nature quercetin (Qc) was electrochemically detected through the rare earth metal-based sphere like praseodymium vanadate (PrVO4) entrapped graphitic carbon nitride (g-CN) as electrode modifiers. The nanocomposite was prepared by the one-pot hydrothermal method and characterized by phase compositional and morphology-based techniques. The existing synergistic nature between the PrV@g-CN (praseodymium vanadate@graphitic carbon nitride) makes them have an enhanced electrochemical response towards the Qc than the individual material. The obtained cyclic voltammogram and differential pulse voltammogram profile show one major oxidation peak which is attributed to the conversion of quercetin to quercetin-o-quinone. The PrV@g-CN/GCE (GCE- glassy carbon electrode) shows a good electrochemical active surface area (A = 110 cm2) and linear range between 0.05 and 252.00 µM with a LOD (limit of detection) of 0.002 µM. Moreover, the PrV@g-CN/GCE exhibits good current retention (94.76 %) around 14 days and appreciable repeatability (RSD- 0.5 %) and reproducibility (RSD- 1.3 %) towards the Qc. The real-time implementation of the proposed sensor exhibits a good recovery range towards the black tea (95.00-98.10 %) and green tea (97.80-99.60 %).

Engineered praseodymium sulfide nanocarrier and supramolecular association of anticancer drug for effective delivery to breast cancer cells.

Metal sulfide nanoparticles are synthesized for their biomedical applications, including cancer drug targeting. This paper reports a novel nanocomposite made of praseodymium sulfide nanoparticles and poly-cyclodextrin. The praseodymium sulfide nanoparticles were synthesized hydrothermal, autoclaving the nitrate precursors at 150 °C for 18 hours. The material is characterized using XRD and shows an orthorhombic crystal system with high crystallinity. The size and morphology of the nanomaterial were optimized. The material shows a rod-shaped morphology, as seen in the TEM image, with 150 ± 3 nm length and 25 ± 5 nm width. Particle size analysis supports this size range. The colloidal particles were stable in the aqueous medium without precipitation at neutral pH. The elements in the material in the polymer-coated form and their electronic states are studied by X-ray photoelectron spectroscopy. Thermogravimetry confirms that the material contains about 18.5% of the weight of the polymer. The material has an observable magnetic property at room temperature due to the praseodymium element. The UV-vis-NIR absorption spectrum of the material shows a long absorption range that extends to 1200 nm. The drug 5-fluorouracil is encapsulated in the nanoparticles through host: guest association, and its release profile is analyzed. The release is modulated at a slightly acidic pH, indicating the pH-tunability. The nanoparticles and 5-fluorouracil were taken in the w/w ratio of 2:1 (2/1 mg in 1 mL of deionized water). Further, the in vitro anticancer activity of the drug-encapsulated material is screened on breast cancer and non-cancerous cell lines. The IC50 values are reported, and the advantageous properties of the material as drug carriers are discussed.

Toxicokinetics of praseodymium and cerium administered as chloride salts in Sprague-Dawley rats: impacts of the dose and of co-exposure with additional rare earth elements.

We conducted a rat exposure study to assess the impacts of dose and co-exposure with other rare earth elements (REEs) on the toxicokinetics of praseodymium (Pr) and cerium (Ce). We first determined the kinetic profiles of elemental Pr and Ce in blood, urine and feces along with tissue levels at sacrifice on the seventh day following intravenous injection of PrCl3 or CeCl3 at 0.3 or 1 mg/kg bw (of the chloride salts) in adult male Sprague-Dawley rats (n = 5 per group). In blood, Pr and Ce half-lives for the initial phase (t1/2α) increased with increasing doses, while their half-lives for the terminal phase (t1/2ß) were similar at both doses. In urine, a minor excretion route, no significant effect of the dose on the cumulative excretion was apparent. In feces, a major excretion route, the fraction of the Pr dose recovered was significantly lower at the 1 mg/kg bw dose compared to the 0.3 mg/kg bw dose, while no significant dose effect was apparent for Ce. In the liver and spleen, which are the main sites of REEs accumulation, there was a significant effect of the dose only for Ce retention in the spleen (i.e., increased retention of Ce in spleen at higher dose). Results were compared with those of a previous toxicokinetic study with a similar design but an exposure to a quaternary mixture of CeCl3, PrCl3, NdCl3 and YCl3, each administered at 0.3 mg/kg bw or 1 mg/kg bw. A mixture effect was apparent for the initial elimination phase (t1/2α) of Pr and Ce from blood and for the fecal excretion of Ce at the 1 mg/kg bw. In urine and liver, there was no evident overall mixture effect; in the spleen, there was a higher retention of Pr and Ce in rats exposed to the mixture at the 0.3 mg/kg bw, but not at the 1 mg/kg bw dose. Overall, this study showed that the dose and mixture exposure are two important factors to consider as determinants of the toxicokinetics of REEs.

Microwave-assisted synthesis of praseodymium (Pr)-doped ZnS QDs such as nanoparticles for optoelectronic applications.

Praseodymium (Pr)-doped ZnS nanoparticles were synthesized using a low-cost microwave-assisted technique and investigations on their structure, morphology, optical properties, Raman resonance, dielectric properties, and luminescence were conducted. Broad X-ray diffraction peaks suggested the formation of low-dimensional Pr-doped ZnS nanoparticles with a cubic structure that was validated using transmission electron microscopy (TEM)/high-resolution TEM analysis. The energy gaps were identified using diffuse reflectance spectroscopy and it was found that the values varied between 3.54eV and 3.61eV for different samples. Vibrational experiments on Pr-doped ZnS nanoparticles revealed significant Raman modes at ~270 and ~350 cm-1 that were associated with optical phonon modes that are shifted to lower wavenumbers, indicating phonon confinement in the synthesized products. The photoluminescence (PL) spectra of all samples demonstrated that the pure and Pr-doped ZnS nanoparticles were three-level laser active materials. Energy-dispersive X-ray spectroscopy and mapping study confirmed the homogeneous presence of Pr in ZnS. TEM studies showed that the particles were of very small size and in the cubic phase. The samples had high dielectric constant values between 13 and 24 and low loss values, according to the dielectric analysis. With an increase in frequency and a change in the Pr content of ZnS, an intense peak could be seen in the PL spectra at a wavelength of 360 nm, and some other peaks observed corresponded to the transition of Pr3+ . The produced nanoparticles were appropriate for optoelectronic applications due to their short dimension, high energy gap, high dielectric constant, and low loss values.

Enhancing catalytic activity through the construction of praseodymium tungstate decorated on hierarchical three-dimensional porous biocarbon for determination of furazolidone in aquatic samples.

Boosting catalytic performance as a vital role for an electrochemical sensor for monitoring various hazardous nitro drugs. Herein, an inexpensive, facile, and eco-friendly construction of praseodymium tungstate decorated on three dimensional porous biocarbon (PrW/3D-PBC) for electrochemical determination of carcinogenic residue furazolidone (FZ). The nanostructured PrW nanoparticles were prepared by solvent evaporation from peroxo-tungstic acid and 3D-PBC was prepared from biomass precursor under the carbonization method. Furthermore, the composite of PrW decorated on 3D-PBC was prepared by an ultrasonic-assisted wet chemical approach. Besides, the composite characterization of crystalline, functional group, degree of carbonization, chemical states, and morphology were utilized by theXRD, FTIR, RAMAN, XPS, and FESEM analysis. These 3D porous carbon decorated PrW nanoparticles facilitate the electrochemical anchoring sites, surface area, and ease of diffusion layers towards the detection of hazardous nitro pollutant FZ by using CV analysis. The low LOD and high sensitivity were achieved by FZ determination through using LSV and DPV techniques. The practical capability of the PrW/3D-PBC/GCE sensor was determined by using aquatic samples to achieve a good recovery result. These results instigate that the PrW/3D-PBC will be an efficient electrocatalytic material for FZ sensor in environmental aquatic samples.

Interaction of the Fungal Metabolite Harzianic Acid with Rare-Earth Cations (Pr3+, Eu3+, Ho3+, Tm3+).

Rare-earth elements (REEs) are in all respect a class of new contaminants that may have toxic effects on organisms and microorganisms and information on their interactions with natural ligands should be of value to predict and control their diffusion in natural environments. In the current study, we investigate interactions of tripositive cations of praseodymium, europium, holmium, and thulium with harzianic acid (H2L), a secondary metabolite produced by selected strains of fungi belonging to the Trichoderma genus. We applied the same techniques and workflow previously employed in an analogous study concerning lanthanum, neodymium, samarium, and gadolinium tripositive cations. Therefore, in the current study, HPLC-ESI-HRMS experiments, circular dichroism (CD), and UV-Vis spectrophotometric absorption data, as well as accurate pH measurements, were applied to characterize bonding interactions between harzianic acid and Pr3+, Eu3+, Ho3+, and Tm3+ cations. Problems connected to the low solubility of harzianic acid in water were overcome by employing a 0.1 M NaClO4/(CH3OH + H2O 50/50 w/w) mixed solvent. For Pr3+, Ho3+, and Tm3+, only the mono complexes PrL+, HoL+, and TmL+ were detected and their formation constant determined. Eu3+ forms almost exclusively the bis complex EuL2- for which the corresponding formation constant is reported; under our experimental conditions, the mono complex EuL+ is irrelevant. Combining the results of the present and previous studies, a picture of interactions of harzianic acid with rare-earth cations extending over 8 of the 17 REEs can be composed. In order to complement chemical information with toxicological information, a battery of bioassays was applied to evaluate the effects of praseodymium, europium, holmium, and thulium tripositive cations on a suite of bioindicators including Aliivibrio fischeri (Gram-negative bacterium), Raphidocelis subcapitata (green alga), and Daphnia magna (microcrustacean), and median effective concentration (EC50) values of Pr3+, Eu3+, Ho3+, and Tm3+ for the tested species were assessed.

Fabrication of Praseodymium Vanadate Nanoparticles on Disposable Strip for Rapid and Real-Time Amperometric Sensing of Arsenic Drug Roxarsone.

Nanomaterials have versatile properties owing to their high surface-to-volume ratio and can thus be used in a variety of applications. This work focused on applying a facile hydrothermal strategy to prepare praseodymium vanadate nanoparticles due to the importance of nanoparticles in today's society and the fact that their synthesis might be a challenging endeavor. The structural and morphological characterizations were carried out to confirm the influence of the optimizations on the reaction's outcomes, which revealed praseodymium vanadate (PrVO4) with a tetragonal crystal system. In this regard, the proposed development of electrochemical sensors based on the PrVO4 nanocatalyst for the real-time detection of arsenic drug roxarsone (RXS) is a primary concern. The detection was measured by amperometric (i-t) signals where PrVO4/SPCE, as a new electrochemical sensing medium for RXS detection, increased the sensitivity of the sensor to about ∼2.5 folds compared to the previously reported ones. In the concentration range of 0.001-551.78 µM, the suggested PrVO4/SPCE sensor has a high sensitivity for RXS, with a detection limit of 0.4 nM. Furthermore, the impact of several selected potential interferences, operational stability (2000 s), and reproducibility measurements have no discernible effect on RXS sensing, making it the ideal sensing device feasible for technical analysis. The real-time analysis reveals the excellent efficiency and reliability of the prosed sensor toward RXS detection with favorable recovery ranges between ±97.00-99.66% for chicken, egg, water, and urine samples.

Pr3+ doped NaYF4 and LiYF4 nanocrystals combining visible-to-UVC upconversion and NIR-to-NIR-II downconversion luminescence emissions for biomedical applications.

Lanthanide-doped fluoride nanocrystals (NCs) are known to exhibit unique optical properties, such as upconversion and downconversion luminescence (UCL and DCL), which can be employed for various applications. In this work, we demonstrate that by doping praseodymium(III) and ytterbium(III) ions (Pr3+ and Yb3+) into a nanosized fluoride matrix (i.e. NaYF4 and LiYF4), it is possible to combine their UCL and DCL properties that can be concurrently used for biomedical applications. In particular, the emissive modes combined in a single nanoparticle co-doped with Pr3+ and Yb3+ include DCL emission (excited at 980 nm and peaked at 1320 nm), which can be used for near infrared (NIR) DCL bioimaging in the NIR-II window of biological tissue transparency (∼1000-1350 nm) and UCL emission (excited at 447 nm and peaked at 275 nm) that can be employed for germicide action (via irradiation by light in the UVC range). A possibility of the latter was demonstrated by the denaturation of double-stranded DNA (dsDNA) into single-stranded ones that was caused by the UVC UCL emission from the NCs under 447 nm irradiation; it was evidenced by the hyperchromicity observed in the irradiated dsDNA solution and also by a fluorometric analysis of DNA unwinding (FADU) assay. Concurrently, the possibility of NIR-II luminescence bioimaging through biological tissues (bovine tooth and chicken flesh) was demonstrated. The proposed concept paves a way for NIR-II imaging guided antimicrobial phototherapy using lanthanide-doped fluoride nanocrystals.

Peroxide-Selective Reduction of O2 at Redox-Inactive Rare-Earth(III) Triflates Generates an Ambiphilic Peroxide.

Metal peroxides are key species involved in a range of critical biological and synthetic processes. Rare-earth (group III and the lanthanides; Sc, Y, La-Lu) peroxides have been implicated as reactive intermediates in catalysis; however, reactivity studies of isolated, structurally characterized rare-earth peroxides have been limited. Herein, we report the peroxide-selective (93-99% O22-) reduction of dioxygen (O2) at redox-inactive rare-earth triflates in methanol using a mild metallocene reductant, decamethylferrocene (Fc*). The first molecular praseodymium peroxide ([PrIII2(O22-)(18C6)2(EG)2][OTf]4; 18C6 = 18-crown-6, EG = ethylene glycol, -OTf = -O3SCF3; 2-Pr) was isolated and characterized by single-crystal X-ray diffraction, Raman spectroscopy, and NMR spectroscopy. 2-Pr displays high thermal stability (120 °C, 50 mTorr), is protonated by mild organic acids [pKa1(MeOH) = 5.09 ± 0.23], and engages in electrophilic (e.g., oxygen atom transfer) and nucleophilic (e.g., phosphate-ester cleavage) reactivity. Our mechanistic studies reveal that the rate of oxygen reduction is dictated by metal-ion accessibility, rather than Lewis acidity, and suggest new opportunities for differentiated reactivity of redox-inactive metal ions by leveraging weak metal-ligand binding events preceding electron transfer.

Migration of Trivalent Praseodymium from Tombarthite Sewage by Microtubule Ultrafiltration Reactor with Organophosphorus in Fuel Oil.

A microtubule ultrafiltration reactor (MUFR), with an organophosphorus system containing a sewage section with buffer liquid acetic acid and an enrichment section with aqua fortis liquid and organophosphorus dissolved in fuel oil, has been studied for praseodymium(III) migration. Many factors of praseodymium(III) migration using MUFR need to be explored, including hydrogen ion molarity (or pH), cinit of praseodymium(III), the different ionic strengths of rare-earth mine sewage, the volume ratio of organophosphorus fuel oil and aqua fortis liquid (O/A), aqua fortis' molarity, organophosphorus' molarity, and the effects of different acid liquids in the enrichment section on praseodymium(III) migration with MUFR. The virtues of MUFR compared to conventional migration were explored. The effects of the hydrodynamic properties (stability and flow velocity) and UF system parameters (internal diameter of the microtubule, tubule shell thickness, void ratio), etc., on the mass migration performance of the MUFR process for praseodymium(III) migration were also studied. The experimental results show that the best migration prerequisites of praseodymium(III) were obtained as follows: an aqua fortis molarity of 4.00 mol/L, an organophosphorus molarity of 0.200 mol/L, an O/A of 0.6 in the enrichment section, and a pH value of 4.80 in the sewage section. The ionic strength of rare-earth mine sewage had no obvious effect on praseodymium(III) migration. When the cinit of praseodymium(III) molarity was 1.58 × 10-4 mol/L, the migration percentage of praseodymium(III) reached 95.2% in 160 min.

Removal of 142Pr from nuclear purity water using hydroxyapatite.

The adsorption of praseodymium using hydroxyapatite was evaluated. The hydroxyapatite (HAP) was characterized by X-ray diffraction (JCPDS 01-04-3708), scanning electron microscopy, BET specific surface area (54.2 m2/g), and point of zero charge (6.5). Adsorption kinetics and isotherms were evaluated at pH of 3 and 142Pr was determined using a gamma spectrometer. The adsorption of praseodymium was fast (1 min of contact) with an adsorption capacity of 1.68 mg/g and the data were best adjusted to the pseudo-second-order model, whereas the data of adsorption isotherm were best adjusted to the Langmuir model with a maximum adsorption capacity of 39.16 ± 0.20 mg/g. The thermodynamic parameters indicated that a physicochemical mechanism took place in the adsorption of praseodymium by HAP (adsorption enthalpy = 31.65 kJ/mol), the randomness of the system increased (adsorption entropy = 0.16 kJ/mol), and according with Gibbs free energy, the adsorption process was spontaneous at high temperature. The praseodymium in the hydroxyapatite is stable, it could not be desorbed using different solutions (ammonium sulfate, calcium chloride, sodium chloride, hydrochloric acid, and sodium hydroxide).

Pr(H3BNMe2BH3)3 and Pr(thd)3 as Volatile Carriers for Actinium-225. Deposition of Actinium-Doped Praseodymium Boride Thin Films for Potential Use in Brachytherapy.

Here we show that the praseodymium N,N-dimethylaminodiboranate complex Pr(H3BNMe2BH3)3 and the 2,2,6,6-tetramethylheptane-3,5-dionate complex Pr(thd)3 can serve as volatile carriers for 225Ac. The actinium coordination complexes Ac(H3BNMe2BH3)3 and Ac(thd)3 are the likely species subliming with the carrier material. A sample of 225Ac-doped Pr(H3BNMe2BH3)3 was used to deposit amorphous 225Ac-doped praseodymium boride films on glass and Si(100) at 300 °C. The α emission spectra of the refractory films are well-resolved, suggesting that they could be used as radioactive implants for brachytherapy and related treatments.

Praseodymium trivalent ion is an effective inhibitor of mitochondrial basic amino acids and carnitine/acylcarnitine carriers.

We herein report the identification of the lantanide praseodymium trivalent ion Pr3+ as inhibitor of mitochondrial transporters for basic amino acids and phylogenetically related carriers belonging to the Slc25 family. The inhibitory effect of Pr3+ has been tested using mitochondrial transporters reconstituted into liposomes being effective in the micromolar range, acting as a competitive inhibitor of the human basic amino acids carrier (BAC, Slc25A29), the human carnitine/acylcarnitine carrier (CAC, Slc25A20). Furthermore, we provide computational evidence that the complete inhibition of the transport activity of the recombinant proteins is due to the Pr3+ coordination to key acidic residues of the matrix salt bridge network. Besides being used as a first choice stop inhibitor for functional studies in vitro of mitochondrial carriers reconstituted in proteoliposomes, Pr3+ might also represent a useful tool for structural studies of the mitochondrial carrier family.

Surfactant-Assisted Synthesis of Praseodymium Orthovanadate Nanofiber-Supported NiFe-Layered Double Hydroxide Bifunctional Catalyst: The Electrochemical Detection and Degradation of Diphenylamine.

Physiological storage disorders are caused by ineffective post-harvest handling of horticultural crops, particularly fruits. To address these post-harvest concerns, diphenylamine (DPAH•+) is widely used as a preservative to prevent fruit degradation and surface scald during storage around the world. Humans are negatively affected by the use of high concentrations of DPAH•+ because of the various health complications related to its exposure. As a result, accurate detection and quantification of DPAH•+ residues in treated fruits are critical. Rare earth metal orthovanadates, which have excellent physical and chemical properties, are potential materials for electrochemical sensors in this area. Herein, we present a simple and direct ultrasonication technique for the surfactant-assisted synthesis of praseodymium orthovanadate (PrVO4 or PrV) loaded on nickel iron layered double hydroxide (NiFe-LDH) synthesized with deep eutectic solvent assistance, as well as its application as an effective catalyst in the detection and degradation of DPAH•+ in fruits and water samples. The current work presents supreme electrochemical features of a PrV@NiFe-LDH-modified screen-printed carbon electrode (SPCE) where cetyltrimethylammonium bromide (CTAB) surfactant-driven fabrication of PrV directs the formation of highly qualified engineered structures and the deep eutectic solvent based green synthesis of NiFe-LDH creates hierarchical lamellar structures following the principles of green chemistry. PrV and NiFe-LDH combine to produce a synergistic effect that improves the number of active sites, charge transfer kinetics, and electronic conductivity. Differential pulse voltammetry analysis of PrV@NiFe-LDH/SPCE reveals a dynamic working range (0.005-226.26 µM), increased sensitivity (133.13 µA µM-1 cm-2), enhanced photocatalytic activity, and low detection limit (0.001 µM), which are considered significant when compared with the former reported electrodes in the literature for the determination of DPAH+ for its real-time applications.

Association of Rare Earth Elements with Passive Smoking among Housewives in Shanxi Province, China.

BACKGROUND: Rare earth elements (REEs) are emerging contaminants. Previous studies reported the association between REEs and active smoking, but little is known about the effects of passive smoking on this condition. In China, female passive smoking is widespread, particularly in rural areas. OBJECTIVE: This study aimed to estimate the relationship between REEs accumulation and passive smoking among rural housewives. METHODS: We recruited 385 subjects in Shanxi Province of northern China, of whom 117 housewives were exposed to passive smoking, and 268 were not. We analyzed 15 REEs in the hair of housewives with ICP-MS, including lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, and yttrium. RESULTS: The results indicated higher levels of 14 REEs except for Sm in both the univariate and adjusted models among the housewives exposed to passive smoking. The increasing linear trend of adjusted odds ratios of 15 REEs supported their association. The Bayesian kernel machine regression (BKMR) models showed that 15 REEs had a significant overall effect, and Eu had a single-exposure effect with passive smoking. CONCLUSION: We concluded that passive smoking might be associated with increased exposure to REEs among rural housewives.

Synthesis and luminescence properties of Pr3+ ion-doped Ba3 Y(PO4 )3 phosphors.

Barium yttrium phosphate (BYP) phosphor doped with trivalent praseodymium ions (BaY(1-x) (PO4 )3 :Pr3+ (x = 0, 0.01, 0.05, 0.1, 0.15, and 0.2 wt%) was synthesized using a high temperature solid-state reaction method. Structural properties were analyzed through X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. XRD patterns confirmed the structure of the synthesized phosphor and average crystalline size was estimated (approximately 63.8 Å). Vibrational functional groups were identified using FTIR spectroscopy. The emission spectrum was recorded under an 444 nm excitation wavelength, which showed various emission transitions of Pr3+ ions. Commission Internationale de l'éclairage coordinates, colour purity, and colour correlated temperature values were calculated for the BYP:Pr3+ phosphors and these coordinate values fell in the yellow region of the visible spectrum.

Hexameric to Trimeric Lanthanide-Included Selenotungstates and Their 2D Honeycomb Organic-Inorganic Hybrid Films Used for Detecting Ochratoxin A.

Two types of organic-inorganic hybrid structure-related lanthanide (Ln)-included selenotungstates (Ln-SeTs) [H2N(CH3)2]11Na7[Ce4(H2PTCA)2(H2O)12(HICA)]2[SeW4O17]2[W2O5]4[SeW9O33]4·64H2O (1, H3PTCA = 1,2,3-propanetricarboxylic acid, H2ICA = itaconic acid) and [H2N(CH3)2]6Na4[Ln4SeW8(H2O)14(H2PTCA)2O28] [SeW9O33]2·31H2O [Ln = Pr3+ (2), Nd3+ (3)] were obtained by Ln nature control. The primary frameworks of 1-3 are composed of trivacant Keggin-type [B-α-SeW9O33]8- and [SeW4Om]n- [Ln = Ce3+ (1), m = 17, n = 6; Ln = Pr3+ (2), Nd3+ (3), m = 18, n = 8] fragments bridged by organic ligands and Ln clusters. Intriguingly, Ln nature results in the degradation of hexameric 1 to trimeric 2-3. Besides, 1@DMDSA and 3@DMDSA composites (DMDSA·Cl = dimethyl distearylammonium chloride) were prepared through the cation exchange method, which were then reorganized to form two-dimensional (2D) honeycomb thin films by the breath figure method. Using these honeycomb thin films as electrode materials, the aptasensors were further established by utilizing methylene blue as an indicator and cDNA and Au nanoparticles as signal amplifiers to enhance the response signal so as to realize the purpose of ochratoxin A (OTA) detection. This work provides a new platform for detecting OTA and explores the application potential of POM-based composites in biological and clinical analyses.

Two new lanthanide complexes with 5-(Pyrazol-1-yl)nicotinic acid: Structures and their anti-cancer properties.

Two new lanthanide complexes [PrL2(EA)2]NO3 (complex 1) and [SmL2(EA)2]NO3 (complex 2) (H2L = 5-(Pyrazol-1-yl)nicotinic acid, EA = CH3CH2OH) were synthesized. The structures were characterized by single crystal X-ray and elemental analysis. The interaction between the complex and fish sperm DNA(FS-DNA) was monitored using ultraviolet and fluorescence spectroscopy, and the binding constants were determined. Both complexes showed the ability to effectively bind DNA, and the molecular docking technology was used to simulate the binding of the complex and DNA. In addition, through the annexin V-Fluorescein Isothiocyanate(FITC)/ Propidium Iodide (PI) test experiment, tetrazollium [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) in vitro test, and cell morphology apoptosis studies, it was shown that the complex can effectively induce HeLa tumor cell apoptosis. Compared with cisplatin and complex, complex 1 shows significant cancer cell inhibition, and we hope that this new type of complex will open up new ways for the next generation of drugs in biomedical applications.

Effect of the dose on the toxicokinetics of a quaternary mixture of rare earth elements administered to rats.

Large human biomonitoring studies are starting to assess exposure to rare earth elements (REEs). Yet, there is a paucity of data on the toxicokinetics of these substances to help interpret biomonitoring data. The objective of the study was to document the effect of the administered dose on the toxicokinetics of REEs. Male Sprague-Dawley rats were injected intravenously with 0.3, 1 or 10 mg/kg body weight (bw) of praseodynium chloride (PrCl3), cerium chloride (CeCl3), neodymium chloride (NdCl3) and yttrium chloride (YCl3) administered together as a mixture. Serial blood samples were withdrawn up to 72 h following injection, and urine and feces were collected at predefined time intervals up to 7 days post-dosing. The REEs were measured by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). For a given REE dose, the time courses in blood, urine and feces were similar for all four REEs. However, the REE dose administered significantly impacted their kinetics, as lower cumulative excretion in urine and feces was associated with higher REE doses. The fraction of REE remaining in rat tissues at the terminal necropsy on post-dosing day 7 also increased with the dose administered, most notably in the lungs and spleen at the 10 mg/kg bw dose. The toxicokinetic parameters calculated from the blood concentration-time profiles further showed significant increases in the mean residence time (MRTIV) for all four REEs at the 10 mg/kg bw dose. The shift in the REE kinetics at high dose may be explained by a higher retention in lysosomes, the main organelle responsible for accumulation of these REEs in different tissues.

Praseodymium selective fluorescence recognition based on GdPO4: Tb3+ probe via energy transfer from Tb3+ to Pr3+ ions.

A novel strategy is proposed based on the efficient energy transfer from Tb3+ to Pr3+ for the sensitive and selective discrimination of praseodymium ions due to the matched energy levels of 5D4 (Tb3+) and 3P0 (Pr3+). The electron of Tb3+ transfers from the ground state to the excited state under the excitation of ultraviolet light and relaxes to the 5D4 level. In the presence of Pr3+ the electron has no time to return to the ground state, thus it transfers to the 3P0 level of Pr3+ resulting in the quenching of Tb3+ luminescence. In the case of GdPO4: Tb3+ nanowire, its fluorescence intensity at 545 nm linearly decreased when Pr3+ concentration ranged from 1 × 10-7 to 1 × 10-5 M, and the detection limit was 75 nM. To further investigate the sensing mechanism, CePO4: Tb3+, YPO4: Tb3+, and YBO3: Tb3+ nanoparticles were also synthesized for Pr3+ ion detection. For all materials, similar fluorescence quenching by Pr3+ ions occurred, which confirmed the efficient energy transfer from Tb3+ to Pr3+ ions. Utilizing the matched energy levels of 5D4 (Tb3+) and 3P0 (Pr3+), for the first time, we proposed a novel strategy (taking GdPO4: Tb3+ probe as the example) based on the efficient energy transfer from Tb3+ to Pr3+ for the sensitive and selective discrimination of praseodymium ions.