Synthesis of Eu(3+)- and Er(3+)/Yb(3+)-doped GdVO4 nanoparticles in reverse micelles and their multifunctional luminescence properties are presented. Using cyclohexane, Triton X-100, and n-pentanol ...as the oil, surfactant, and co-surfactant, respectively, crystalline nanoparticles with ~4 nm diameter are prepared at low temperatures. The particle size assessed using transmission electron microscopy is similar to the crystallite size obtained from X-ray diffraction measurements, suggesting that each particle comprises a single crystallite. Eu(3+)-doped GdVO4 nanoparticles emit red light through downconversion upon UV excitation. Er(3+)/Yb(3+)-doped GdVO4 nanoparticles exhibit several functions; apart from the downconversion of UV radiation into visible green light, they act as upconvertors, transforming near-infrared excitation (980 nm) into visible green light. The ratio of green emissions from (2)H11/2 → (2)I15/2 and (4)S3/2 → (4)I15/2 transitions is temperature dependent and can be used for nanoscale temperature sensing with near-infrared excitation. The relative sensor sensitivity is 1.11%K(-1), which is among the highest sensitivities recorded for upconversion-luminescence-based thermometers.
Eu(III)-doped GdVO4 nanocrystals were prepared by precipitation of the Gd(III) and (Eu(III) citrate complexes, with fractions of Eu(III) ranging from 5 to 100mol%. Their red fluorescence is strongly ...quenched by H2O2, and this finding forms the basis for a fluorometric assay for H2O2 with a limit of detection as low as 1.6μM. The probe was further employed to design a highly sensitive enzymatic assay for glucose.
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•Synthesis of fluorescent nanocrystals (NCs) of type GdVO4 and doped with varying fractions of Eu(III) ions.•The NCs are shown to be viable fluorescent probes for hydrogen peroxide.•The NCs can be used as probes for sensing glucose via the hydrogen peroxide produced by enzymatic action of glucose oxidase.•Detection limits are as low as 1.6μM for H2O2 and 2.1μM for glucose.
The authors describe the preparation of Eu3+-doped GdVO4 nanocrystals (NCs) by precipitation of the Gd3+(Eu3+)-citrate complex which was then converted to the respective vanadate by dialysis. The fractions of Eu3+ ranged from 5 to 100mol%. The NCs were characterized by XRD, TEM, ICP-OES and dynamic light scattering which revealed that they possess superior colloidal stability in aqueous solutions in that no precipitation can be observed even after several months. The NCs display red and largely red-shifted fluorescence (peaking at 618nm) on photoexcitation at around 300nm. Fluorescence is strongly quenched by hydrogen peroxide. It is also shown that the fraction of doping with Eu3+ strongly affects quenchability. Most efficient quenching by H2O2 is observed if the NCs are doped with 50% of Eu3+. The findings were exploited to develop a fluorometric assay for H2O2 that works in the 5 to 250μM concentration range, with a limit of detection as low as 1.6μM (at a signal-to-noise ratio of 3). The probe was further employed to design a highly sensitive enzymatic assay for glucose via measurement of the quantity of H2O2 formed as a result of the catalytic action of glucose oxidase.
In order to compare spectroscopic properties between nanosized and that in single crystal form of YPO4:Pr3+, temperature-dependence of the red emission from 3P0 → 3H4 and 1D2 → 3H4 transitions of ...YPO4:0.1 at. % Pr3+ nanopowders has been investigated in details. The emission spectra of the sample in size of 20 nm, under selective excitation at 3P2, measured at different temperatures, T = 10, 100, 200 and 300 K have been recorded. The variation of emission intensity of each 3P0 → 3H4 and 1D2 → 3H4 against temperature has been investigated. Several spectral lines constitute 1D2 → 3H4 emission, assigned to transitions between 1D2 and 3H4 Stark levels are observed with no noticeable shifts between them and those observed at the single crystal. It is found that 1D2 → 3H4 emission intensity dominates that of 3P0 → 3H4 transition, pointing out the high efficiency of the multiphonon relaxation (MPR) process from 3P0 to 1D2. Fitting the temperature dependence of 3P0 → 3H4 emission intensity permits to estimate the phonons and their energies involved in non-radiatively transition between 3P0 and 1D2 levels, which are found different from single crystal. Also, fitting the multiphonon relaxation (MPR) rates against temperature, extracted from the measured 1D2 lifetime gives information that seven phonons can be involved to bridge the gap between 1D2 and 1G4. Furthermore, the possibility to use the YPO4: 0.1 at. % Pr3+ in the nano-thermometry application in temperature range T = 10–300 K was investigated.
•Temperature-dependence of the red emission YPO4:Pr3+ nanophosphor has been studied.•The phonons and their energies involved between 3P0 and 1D2 are different from single crystal.•Seven high energy phonons are involved to can bridge the gap between 1D2 and 1G4 by MPR process.•The possibility to use the YPO4: Pr3+ in the nano-thermometry application was investigated.
Nanoparticle‐mediated photothermal therapy (NP‐PTT) constitutes a flexible, highly selective, cost effective, and accurate tool for cancer treatment alone or in combination with other therapies such ...as radiotherapy or chemotherapy. The future application of NP‐PTT in real life mainly depends on the design and synthesis of novel multifunctional nanoparticles that could overcome the current limitations of NP‐PTT such as limited penetration depth and absence of therapy control. In this work, ultrasmall (≈2.4 nm) NdVO4 stoichiometric (100% constituent Nd3+ ions) nanoparticles are reported, which are capable of in vivo sub‐tissue localized heating under 808 nm optical excitation while providing, simultaneously, the possibility of high penetration near‐infrared fluorescence imaging. Ultrasmall stoichiometric NdVO4 nanoparticles have evidenced a superior light‐to‐heat conversion efficiency. This is explained in terms of their large absorption cross‐section at 808 nm (consequence of the particular spectroscopic properties of neodymium ions in NdVO4 and of the high neodymium content) as well as to their ultrasmall size that leads to large nonradiative decay rates. Results included in this work introduce ultrasmall, NdVO4 stoichiometric nanoparticles to the scientific community as multifunctional photothermal agents that could be considered as an alternative to traditional systems such as metallic, organic, or carbon‐based nanoparticles.
IR‐emitting NdVO4 ultrasmall nanoparticles show a remarkable photothermal conversion efficiency (72.1%) under 808 nm irradiation, which makes them particularly interesting for combined photothermal therapy and bioimaging. Their outsanding light‐to‐heat conversion capability, studied ex vivo and in vivo, would allow for photothermal treatments at laser intensities much lower than the ones used up to this moment with fluorescent rare earth‐based nanomaterials.
Lumbar pain is a condition of discomfort in the lower back caused by numerous factors, lasting for short or longer periods of time. Healthcare professionals, regardless of the type of care they are ...engaged in, are at risk of lumbar pain. This is the first study that deals with the problem of lumbar syndrome in health workers in Montenegro.
This cross-sectional study included full-time health workers employed in the Clinical Center of Montenegro who were involved in the treatment of COVID-19 patients during 2020 and 2021. The survey consisted of general questions for collecting socio-demographic and COVID-19 engagement data; the Modified Nordic questionnaire was used for the analysis of musculoskeletal symptoms, and the EQ-5D-questionnaire was used to measure the quality of life associated with health.
The one-year prevalence of lumbar pain was 68.1%. Factors associated with lumbar pain were as follows: a higher degree of physical inactivity (each subject with a higher degree of physical inactivity had a 24% higher chance of occurrence of lumbar pain); a higher degree of load and over-engagement during the COVID-19 pandemic (each subject with a higher degree of workload had a nearly 50% higher chance of occurrence of lumbar pain); duration of engagement during the COVID-19 pandemic (subjects engaged up to a month were 4 times more likely to develop lumbar pain, and subjects engaged for 1-3 months were 3.5 times more likely to develop lumbar pain compared to those who were not engaged in COVID-19 treatment). This study also confirms that lumbar syndrome affects the quality of life of health workers.
Lumbar syndrome is highly prevalent among healthcare professionals in the Clinical Center of Montenegro, especially in the population of nurses, where evidence-based preventive measures are needed.
Nowadays a large variety of applications are based on solid nanoparticles dispersed in liquids—so called nanofluids. The interaction between the fluid and the nanoparticles plays a decisive role in ...the physical properties of the nanofluid. A novel approach based on the nonradiative energy transfer between two small luminescent nanocrystals (GdVO4:Nd3+ and GdVO4:Yb3+) dispersed in water is used in this work to investigate how temperature affects both the processes of interaction between nanoparticles and the effect of the fluid on the nanoparticles. From a systematic analysis of the effect of temperature on the GdVO4:Nd3+ → GdVO4:Yb3+ interparticle energy transfer, it can be concluded that a dramatic increase in the energy transfer efficiency occurs for temperatures above 45 °C. This change is properly explained by taking into account a crossover existing in diverse water properties that occurs at about this temperature. The obtained results allow elucidation on the molecular arrangement of water molecules below and above this crossover temperature. In addition, it is observed that an energy transfer process is produced as a result of interparticle collisions that induce irreversible ion exchange between the interacting nanoparticles.
The interaction between nanoparticles and fluids has a major role in the properties of nanofluids. By means of nonradiative energy transfer between small luminescent nanoparticles dispersed in water, this work reveals how temperature affects the interactions between a liquid and particles. A crossover affecting diverse temperature‐dependent water properties is evidenced in the change of the luminescence of the nanoparticles.
This title arises from the knowledge collected by the European Research Network COST Action 637 involving 27 European countries and the USA. Besides the large number of important papers, reports, and ...reviews already available on various aspects of arsenic occurrence in the environment, water, and food and related human exposure, this book fills a gap in the field concerning assessment risks, implications, challenges, and actions required by public health managers.
Monoclinic scheelite-type BiVO4 is currently considered as one of the most promising non-titania photocatalysts, wheras tetragonal zircon-type BiVO4 is still poorly understood. Herein, a new and ...simple synthetic approach was applied and nanostructured single-phase zircon-type BiVO4 was successfully prepared by a controllable ethylene-glycol colloidal route. In addition, nanostructured monoclinic scheelite-type BiVO4 powders were also fabricated through annealing of the as-prepared samples. A comparative study of the two BiVO4 polymorphs was conducted and it turned out that the novel synthetic approach had a significant impact on porosity and photocatalytic performance of zircon-structured BiVO4. All the prepared materials, as-prepared and annealed, were mesoporous, while measured values of specific surface area of some zircon-structured samples (∼34 m2/g) were ∼7 times higher than those reported thus far for this phase. Interestingly, for the first time, zircon-type BiVO4, previously considered to be a poor photocatalyst, exhibited a better overall performance in degradation of methyl orange compared to monoclinic scheelite-type BiVO4. Hence, it could be expected that the here-presented synthesis and observations will both arouse interest in scarcely studied tetragonal zircon-type BiVO4 and facilitate as well as speed up further research of its properties.
Background There is no clear evidence whether pirfenidone has a benefit in patients with probable or possible UIP, i.e. when idiopathic pulmonary fibrosis (IPF) is diagnosed with a lower degree of ...diagnostic certainty. We report on outcomes of treatment with pirfenidone in IPF patients diagnosed with various degrees of certainty. Methods and findings We followed patients in the multi-national European MultiPartner IPF Registry (EMPIRE) first seen between 2015 and 2018. Patients were assessed with HRCT, histopathology and received a multi-disciplinary team (MDT) IPF diagnosis. Endpoints of interest were overall survival (OS), progression-free survival (PFS) and lung function decline. Results A total of 1626 patients were analysed, treated with either pirfenidone (N = 808) or receiving no antifibrotic treatment (N = 818). When patients treated with pirfenidone were compared to patients not receiving antifibrotic treatment, OS (one-, two- and three-year probability of survival 0.871 vs 0.798; 0.728 vs 0.632; 0.579 vs 0.556, P = 0.002), and PFS (one-, two- and three-year probability of survival 0.597 vs 0.536; 0.309 vs 0.281; 0.158 vs 0.148, P = 0.043) was higher, and FVC decline smaller (-0.073 l/yr vs -0.169 l/yr, P = 0.017). The benefit of pirfenidone on OS and PFS was also seen in patients with probable or possible IPF. Conclusions This EMPIRE analysis confirms the favourable outcomes observed for pirfenidone treatment in patients with definitive IPF and indicates benefits also for patients with probable or possible IPF.
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