Surface Plasmon Enhancement of Eu3+ Emission Intensity in LaPO4/Ag Nanoparticles

A promising way to improve the performance of luminescent materials is to combine them with noble metal nanoparticles. Herein, a set of silver/europium-doped lanthanum orthophosphate (Ag/La0.95Eu0.05PO4) nanostructures with different concentrations of silver nanoparticles were prepared and investigated. The presented overlap between the strongest europium (Eu3+) excitation line and the broad silver nanoparticle surface plasmon resonance makes the combination prospective for coupling. X-ray powder diffraction confirmed the monoclinic monazite structure. The transmission electron microscopy revealed particles with a rod-like shape and ~4 aspect ratio. Photoluminescence spectra show characteristic Eu3+ ion red emission. One of the requirements for an enhanced luminescence effect is the precise control of the distance between the noble metal nanoparticles and the emitter ion. The distance is indirectly varied throughout the change of Ag nanoparticle concentration in the La0.95Eu0.05PO4 host. The emission intensity increases with the increase in Ag nanoparticles up to 0.6 mol %, after which the luminescence decreases due to the nanoparticles’ close packing and aggregation leading to the displacement of La0.95Eu0.05PO4 from the vicinity of the metal particles and reabsorption of the emitted light. The emission intensity of La0.95Eu0.05PO4 increases more than three times when the Eu3+ excitation is supported by the localized surface plasmon resonance in the Ag/La0.95Eu0.05PO4 nanostructures

Exploiting High-Energy Emissions of YAlO3:Dy3+ for Sensitivity Improvement of Ratiometric Luminescence Thermometry

The sensitivity of luminescence thermometry is enhanced at high temperatures when using a three-level luminescence intensity ratio approach with Dy3+- activated yttrium aluminum perovskite. This material was synthesized via the Pechini method, and the structure was verified using X-ray diffraction analysis. The average crystallite size was calculated to be around 46 nm. The morphology was examined using scanning electron microscopy, which showed agglomerates composed of densely packed, elongated spherical particles, the majority of which were 80–100 nm in size. The temperature-dependent photoluminescence emission spectra (ex = 353 nm, 300–850 K) included Dy3+ emissions in blue (458 nm), blue (483 nm), and violet (430 nm, T 600 K). Luminescence intensity ratio, the most utilized temperature readout method in luminescent thermometry, was used as the testing method: a) using the intensity ratio of Dy3+ ions and 4I15/2→6H15/2/4F9/2→6H15/2 transitions; and b) employing the third, higher energy 4G11/2 thermalized level, i.e., using the intensity ratio of 4G11/2→6H15/2/4F9/2→6H15/2 transitions, thereby showing the relative sensitivities of 0.41% K−1 and 0.86% K−1 at 600 K, respectively. This more than doubles the increase in sensitivity and therefore demonstrates the method’s usability at high temperatures, although the major limitation of the method is the chemical stability of the host material and the temperature at which the temperature quenching commences. Lastly, it must be noted that at 850 K, the emission intensities from the energetically higher levels were still increasing in YAP: Dy3+

Ge/Al and Ge/Si3N4/Al Core/Shell Quantum Dot Lattices in Alumina: Boosting the Spectral Response by Tensile Strain

We investigated the production conditions and optoelectrical properties of thin film material consisting of regularly ordered core/shell Ge/Al and Ge/Si3N4/Al quantum dots (QDs) in an alumina matrix. The materials were produced by self– assembled growth achieved by means of multilayer magnetron sputtering deposition. We demonstrated the successful fabrication of well-ordered 3D lattices of Ge/Al and Ge/Si3N4/Al core/shell quantum dots with a body-centred tetragonal arrangement within the Al2O3 matrix. The addition of shells to the Ge core enables a strong tuning of the optical and electrical properties of the material. An Al shell induces a bandgap shift toward smaller energies, and, in addition, it prevents Ge oxidation. The addition of a thin Si3N4 shell induces huge changes in the material spectral response, i.e., in the number of extracted excitons produced by a single photon. It increases both the absolute value and the width of the spectral response. For the best sample, we achieved an enhancement of over 250% of the produced number of excitons in the measured energy range. The observed changes are, as it seems, the consequence of the large tensile strain in Ge QDs which is induced by the Si3N4 shell addition and which is measured to be about 3% for the most strained QDs. The tensile strain causes activation of the direct bandgap of germanium, which has a very strong effect on the spectral response of the material

Multiple exciton generation in 3D ordered networks of Ge quantum wires in alumina matrix

Thin films containing 3D-ordered semiconductor quantum wires offer a great tool to improve the properties of photosensitive devices. In the present work, we investigate the photogenerated current in thin films consisting of an interconnected 3D-ordered network of Ge quantum wires in an alumina matrix. The films are prepared using nitrogen-assisted magnetron sputtering co-deposition of Ge and Al2O3. We demonstrate a strong photocurrent generation in the films, much stronger than in similar films containing Ge quantum dots. The enhanced photocurrent generation is the consequence of the multiple exciton generation and the films’ specific structure that allows for efficient carrier transport. Thin film with the largest nitrogen content showed enhanced performance compared to other thin films with 1.6 excitons created after absorption of a single photon at an energy nearly equal to the double bandgap value. The bandgap value depends on the geometrical properties of the quantum wires, and it is close to the maximum of the solar irradiance in this case. In addition, we show that the multiple exciton generation is the most pronounced at the photon energy values equal to multiple values of the thin film bandgap

Comparison of diagnostic accuracy for eight SARS-CoV-2 serological assays

Introduction: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serological tests have been suggested as an additional diagnostic tool in highly suspected cases with a negative molecular test and determination of seroprevalence in population. We compared the diagnostic performance of eight commercial serological assays for IgA, IgM, and IgG antibodies to the SARS-CoV-2 virus. Materials and methods: The comparison study was performed on a total of 76 serum samples: 30 SARS-CoV-2 polymerase chain reaction (PCR)- negative and 46 SARS-CoV-2 PCR-positive patients with asymptomatic to severe disease and symptoms duration from 3-30 days. The study included: three rapid lateral flow immunochromatographic assays (LFIC), two enzyme-linked immunosorbent assays (ELISA), and three chemiluminescence immunoassays (CLIA). Results: Agreement between IgM assays were minimal to moderate (kappa 0.26 to 0.63) and for IgG moderate to excellent (kappa 0.72 to 0.92). Sensitivities improved with > 10 days of symptoms and were: 30% to 89% for IgM; 89% to 100% for IgG; 96% for IgA; 100% for IgA/IgM combination; 96% for total antibodies. Overall specificities were: 90% to 100% for IgM; 85% to 100% for IgG; 90% for IgA; 70% for IgA/IgM combination; 100% for total antibodies. Diagnostic accuracy for IgG ELISA and CIA assays were excellent (AUC ≥ 0.90), without significant difference. IgA showed significantly better diagnostic accuracy than IgM (P < 0.001). Conclusion: There is high variability between IgM assays independently of the assay format, while IgG assays showed moderate to perfect agreement. The appropriate time for testing is crucial for the proper immunity investigation

Comparison of Three Ratiometric Temperature Readings from the Er3+ Upconversion Emission

The emission of Er3+ provides three combinations of emission bands suitable for ratiometric luminescence thermometry. Two combinations utilize ratios of visible emissions (2H11/2→4I15/2 at 523 nm/ 4S3/2→4I15/2 at 542 nm and 4F7/2→4I15/2 at 485 nm/ 4S3/2→4I15/2 at 545 nm), while emissions from the third combination are located in near-infrared, e.g., in the first biological window (2H11/2→4I13/2 at 793 nm/ 4S3/2→4I13/2 at 840 nm). Herein, we aimed to compare thermometric performances of these three different ratiometric readouts on account of their relative sensitivities, resolutions, and repeatability of measurements. For this aim, we prepared Yb3+,Er3+:YF3 nanopowders by oxide fluorination. The structure of the materials was confirmed by X-ray diffraction analysis and particle morphology was evaluated from FE-SEM measurements. Upconversion emission spectra were measured over the 293–473 K range upon excitation by 980 nm radiation. The obtained relative sensitivities on temperature for 523/542, 485/542, and 793/840 emission intensity ratios were 1.06 ± 0.02, 2.03 ± 0.23, and 0.98 ± 0.10%K−1 with temperature resolutions of 0.3, 0.7, and 1.8 K, respectively. The study showed that the higher relative temperature sensitivity does not necessarily lead to the more precise temperature measurement and better resolution, since it may be compromised by a larger uncertainty in measurement of low-intensity emission bands

Use of bendamustin instead of carmustin in autologous stem cell transplantation conditioning – toxicity and infectious complications comparison

Unatrag nekoliko godina u hematologiji i onkologiji globalno sve češći problem postaje prikladna opskrba „starijim i manje zanimljivim“ kemoterapeuticima. Zbog povremene nestašice karmustina, jednog od osnovnih kemoterapeutika pri kondicioniranju prije autologne transplantacije krvotvornih matičnih stanica (ATK S) u oboljelih od limfoma, u našem se centru od 2016. godine on zamjenjuje bendamustinom. U ovom radu retrospektivno analiziramo tijek ATK S-a u 41 bolesnika koji su primili bendamustin u sklopu protokola BeEA M te ga uspoređujemo s tijekom ATK S-a u 40 bolesnika koji su primili karmustin u sklopu protokola BEA M. Medijan oporavka vrijednosti neutrofila (> 0,5 × 109/l) u skupini koja je primila bendamustin iznosio je 11 dana, dok je u skupini kondicioniranoj karmustinom iznosio 10 dana. Medijan oporavka vrijednosti trombocita (> 20 × 109/l) bio je duži kod skupine koja je primala bendamustin (16 prema 13 dana) te su ti bolesnici bili duže ovisni o transfuzijama eritrocita (7 prema 5 dana). Infektivne komplikacije nisu bile češće nakon primjene bendamustina, ali smo nakon primjene karmustina imali veću pojavu mukozitisa II. – III. stupnja (35% prema 12%). Nakon primjene bendamustina zabilježen je jedan slučaj nefrotoksičnosti i kardiotoksičnosti terapije, dok kod primjene karmustina te komplikacije nisu zabilježene. Pri upotrebi bendamustina kod kondicioniranja u naših bolesnika u ovom trenutku nije utvrđena znatnija hematološka toksičnost u odnosu prema karmustinu, ali su prisutni dulji period oporavka vrijednosti trombocita te niža incidencija mukozitisa.Inadequate supply of „old and less interesting“ chemotherapeutic agents is becoming a global issue in hemato-oncology today. In 2016 we were faced with occasional carmustin shortage, one of the most commonly used in autologous transplant conditioning regimens for lymphoma in our centre, so we decided to use bendamustin instead. We performed a retrospective analysis of 41 patients treated at our centre who had received bendamustin within BeEA M protocol and compared them with 40 patients who had received carmustin within BEA M protocol. Both protocols were used as conditioning protocols before autologous stem cell transplantation. Neutrophil recovery median following transplantation (AN C>0,5x109/l) was 11 days in the bendamustin group in comparison to 10 days in the carmustin group.Platelets recovery median following transplantation (PLT>20x109/l) was longer in the bendamustin group (16 vs.13 days) as was blood transfusion dependency (7 vs. 5 days). Infectious complications were not more frequent after bendamustin, but grade II–III mucositis was more frequent in patients who received carmustin (35% vs.12%). Following bendamustin we had one reported case of nephrotoxicity and cardiac toxicity, not reported with carmustin. Bendamustin has shown similar hematologic toxicity compared to carmustin but a longer platelet recovery period and a lower mucositis incidence

The quality of sugar beet, intermedial products and crystalline sugar in 2005. sugar campaign

Osnovna sirovina za proizvodnju šećera u umjerenim sjevernim područjima je šećerna repa. To je biljka u čijem se vretenastom korijenu nalaze pohranjeni šećer i mnogi drugi spojevi, a njihovi udjeli, kao i međusobni odnosi ovise najviše o kemijskom sastavu tla i gnojidbi. Uzimani su uzorci repe, svih međuprodukata tehnološkog procesa proizvodnje šećera (difuznog soka, rijetkog soka, gustog soka, šećerovine A, zelenog sirupa "A", bijelog sirupa "A", šećerovine B, zelenog sirupa "B", bijelog sirupa "B", "B" šećera, klere,"C" šećera, melase, afiniranog "C" šećera i afiniranog "C" sirupa), kao i konačnog produkta, kristal šećera te su im određivani procesni parametri: udjel suhe tvari, polarizacija, kvocijent čistoće, pH-vrijednost, udjel inverta, boja, te Silinov i Švedski broj, kao i postotak mrva, na temelju kojih se definirala kakvoća uzoraka. Na osnovu dobivenih rezultata vidljivo je da je kristal šećer, proizveden tijekom kampanje 2005. godine zadovoljavajuće kakvoće, u skladu s kakvoćom šećerne repe koja se nije razlikovala od prosječne kakvoće repe unatrag deset godina.The basic raw material for sugar production in temperate zones of the north is sugar beet. It is a plant in whose spindle shaped root sugar and numerous other compounds are stored and their shares, as well as their ratio, depend mostly on chemical composition of the soil and fertilisation. Samples of sugar beet, together with samples of all intermedial products in technological process of sugar production (raw juice, thin juice, thick juice, massecuite A, green syrup "A", white syrup "A", massecuite B, green syrup "B", white syrup "B", "B" sugar, standard liquor, "C" sugar, molasses, afinated "C" sugar and afinated "C" syrup) along with samples of final product, crystalline sugar, were taken and their process parameters: dry matter content, polarisation, purity quotient, pH-value, invert sugar content, color, and also, Silin number, Swedish number and crumbs were measured in order to define quality of those samples. The results showed that the crystalline sugar, a product of 2005. sugar campaign, was of satisfactory quality, equal to that in sugar beet, whose quality was as same as the average for the past ten years