Arel – Investigating [Eu(H2O)9]3+ photophysics and creating a method to by-pass luminescence quantum yield determinations

Lanthanide luminescence has been treated separate from molecular photophysics, although the underlying phenomena are the same. As the optical transitions observed in the trivalent lanthanide ions are forbidden, they do belong to the group that molecular photophysics have yet to conquer, yet the experimental descriptors remains valid. Determining these have proven challenging as full control/knowledge of sample composition is a prerequisite. This has been achieved, and here the luminescence quantum yields (ϕlum), luminescence lifetimes (τobs), oscillator strengths (f ), and the rates of non-radiative (knr) and radiative (kr ≡ A) deactivation of [Eu(H2O)9]3+ was determined for the trigonal tricapped prismatic (TTP) coordination geometry. Further, it was shown that instead of a full photophysical characterization, it is possible to relate changes in transition probabilities to the relative parameter Arel, which does not require reference data. While Arel does not afford comparisons between experiments, it resolves emission intensity changes due to emitter properties—changes in A—from intensity changes due to environmental effects—changes in knr, and differences in the number of photons absorbed. When working with fluorescence this may seem trivial, when working with lanthanide luminescence it is not.

Characterization of Extracellular Vesicles from Bronchoalveolar Lavage Fluid and Plasma of Patients with Lung Lesions Using Fluorescence Nanoparticle Tracking Analysis

The current lack of reliable methods for quantifying extracellular vesicles (EVs) isolated from complex biofluids significantly hinders translational applications in EV research. The recently developed fluorescence nanoparticle tracking analysis (FL-NTA) allows for the detection of EV-associated proteins, enabling EV content determination. In this study, we present the first comprehensive phenotyping of bronchopulmonary lavage fluid (BALF)-derived EVs from non-small cell lung cancer (NSCLC) patients using classical EV-characterization methods as well as the FL-NTA method. We found that EV immunolabeling for the specific EV marker combined with the use of the fluorescent mode NTA analysis can provide the concentration, size, distribution, and surface phenotype of EVs in a heterogeneous solution. However, by performing FL-NTA analysis of BALF-derived EVs in comparison to plasma-derived EVs, we reveal the limitations of this method, which is suitable only for relatively pure EV isolates. For more complex fluids such as plasma, this method appears to not be sensitive enough and the measurements can be compromised. Our parallel presentation of NTA-based phenotyping of plasma and BALF EVs emphasizes the great impact of sample composition and purity on FL-NTA analysis that has to be taken into account in the further development of FL-NTA toward the detection of EV-associated cancer biomarkers.

Theoretical analysis of the factors, influencing composition uniformity of the cadmium zinc telluride substrates grown by THM

The effect of the sample composition, variation of the temperature field and the feed material non-homogeneity on uniformity of the growing crystal is considered. It is shown that optimization of the solvent composition makes it possible to minimize the jump of the ZnTe concentration at the seed/crystal boundary. The composition fluctuations at variation of the thermal field during crystal growth are smooth enough and relatively non-significant. The feed composition distribution has, as a rule, a random character. Different harmonics of composition distribution non-uniformity in the feed material differently affect the homogeneity of the growing crystal. Longwave non-uniformities in the feed transform into the growing crystal almost completely. At the wavelength equals to a half of the solvent length or shorter, the perturbations of the growing crystal composition are relatively small. Evidently, the cause of the local composition variations, found in real crystals, is, basically, the feed composition non-uniformities

The impact of government responses to the COVID-19 pandemic on GDP growth: Does strategy matter?

We analyze whether and to what extent strategies employed by governments to fight the COVID-19 pandemic made a difference for GDP growth developments in 2020. Based on the strength and speed with which governments imposed non-pharmaceutical interventions (NPIs) when confronted with waves of infections we distinguish between countries pursuing an elimination strategy and countries following a suppression / mitigation strategy. For a sample of 44 countries fixed effect panel regression results show that NPI changes conducted by elimination strategy countries had a less severe effect on GDP growth than NPI changes in suppression / mitigation strategy countries: strategy matters. However, this result is sensitive to the countries identified as “elimination countries” and to the sample composition. Moreover, we find that exogenous country characteristics drive the choice of strategy. At the same time our results show that countries successfully applying the elimination strategy achieved better health outcomes than their peers without having to accept lower growth.

Glucose uptake in mammalian cells measured by ICP-MS

We developed a sensitive, ratiometric method to measure simultaneously 13C-labeled glucose and rubidium in biological samples using ICP-MS. The method uses probe-assisted ultra-sonication with water to extract 13C-[6C]-labeled-D-glucose and other polar analytes from mammalian tissues. It extracts >80% of the reference value for Rb and >95 % of 13C in a CRM spiked with 13C-[6C]-labeled-D-glucose in the micro-molar range. Using optimized instrument conditions, the method achieves a stable 13C/12C signal without spectral interferences. The 13C/12C signal is independent of sample composition and depends linearly on the concentration of 13C-[6C]-labeled-D-glucose in spiked samples. Overall, the method achieves a limit of detection of 10 uM for 6-C-labeled 13C glucose in biological tissues. This detection capability for carbon in biological matrices by ICP-MS opens a wider range of applications for ICP-MS in biomedical research. As proof-of-principle, we combined 13C detection with the multi-channel capability of ICP-MS to measure glucose and rubidium uptake in the same contracting skeletal muscles. Multi-isotope detection is needed to study many biological processes, including coupled membrane transport. These results demonstrate a capability for carbon detection by ICP-MS that can significantly advance studies of complex biological processes that require multi-isotope detection.

A Comparison of Geosampling and Random Walk Methods for Household Sample Selection in Uttar Pradesh, India

Our research evaluates an innovative sampling technique for household surveys called “geosampling” which leverages recent advances in geographic information systems, computer vision algorithms, and satellite imagery. We compare geosampling to the random walk method. We conducted two surveys in Uttar Pradesh, India: one using geosampling (1,026 completes) and another using random walk (939 completes). We compare the two sampling techniques along three dimensions: (a) performance indicators—response rates and contact attempts; (b) sample composition; and (c) components of variance. We help researchers understand the survey contexts for which geosampling and random walk are best suited.

Sexing as a tool for reinsertion of Amazona aestiva parrots to nature: use of less invasive technique

The sexing birds is considered an important tool for behavioral studies and programs for the reintroduction of animals into the wild. Several techniques are used for this purpose, such as laparoscopy, magnetic resonance and molecular sexing. The first are considered more invasive and stressful for the animal, and the last is considered the most accurate. According to it, the aim of this study was to compare the effectiveness of using three sets of primers in the molecular sexing process of true parrots (Amazona aestiva). Blood samples from 10 animals were collected at a Wildlife Screening Center (CETAS) in Bahia, Brazil. The DNA was extracted and the molecular markers amplified by Polymerase Chain Reaction (PCR) using primer pairs P2/P8, 1237L/1272H and 2250F/2718R. The amplified material was visualized with electrophoresis performed at 2% agarose and 12.5% polyacrylamide gels. Among the primer sets used, the 2250F/2718R pair showed the best results for the sexing process, including visualization of the amplified products on an agarose gel. Agarose gel electrophoresis is considered to be faster and cheaper. The results revealed a sample composition of 5 males (0.5) and 5 females (0.5).

Reduction of Thermal Conductivity for Icosahedral Al-Cu-Fe Quasicrystal through Heavy Element Substitution

Icosahedral Al-Cu-Fe quasicrystal (QC) shows moderate electrical conductivity and low thermal conductivity, and both p- and n-type conduction can be controlled by tuning the sample composition, making it potentially suited for thermoelectric materials. In this work, we investigated the effect of introducing chemical disorder through heavy element substitution on the thermal conductivity of Al-Cu-Fe QC. We substituted Au and Pt elements for Cu up to 3 at% in a composition of Al63Cu25Fe12, i.e., Al63Cu25−x(Au,Pt)xFe12 (x = 0, 1, 2, 3). The substitutions of Au and Pt for Cu reduced the phonon thermal conductivity at 300 K (κph,300K) by up to 17%. The reduction of κph,300K is attributed to a decrease in the specific heat and phonon relaxation time through heavy element substitution. We found that increasing the Pt content reduced the specific heat at high temperatures, which may be caused by the locked state of phasons. The observed glass-like low values of κph,300K (0.9–1.1 W m−1 K−1 at 300 K) for Al63Cu25−x(Au,Pt)xFe12 are close to the lower limit calculated using the Cahill model.

Mixed-Culture Metagenomics of the Microbes Making Sour Beer

Mixed microbial cultures create sour beers but many brewers do not know which microbes comprise their cultures. The objective of this work was to use deep sequencing to identify microorganisms in sour beers brewed by spontaneous and non-spontaneous methods. Twenty samples were received from brewers, which were processed for microbiome analysis by next generation sequencing. For bacteria, primers were used to amplify the V3-V4 region of the 16S rRNA gene; fungal DNA detection was performed using primers to amplify the entire internal transcribed spacer region. The sequencing results were then used for taxonomy assignment, sample composition, and diversity analyses, as well as nucleotide BLAST searching. We identified 60 genera and 140 species of bacteria, of which the most prevalent were Lactobacillus acetotolerans, Pediococcus damnosus, and Ralstonia picketti/mannitolilytica. In fungal identification, 19 genera and 26 species were found, among which the most common yeasts were Brettanomyces bruxellensis and Saccharomyces cerevisiae. In some cases, genetic material from more than 60 microorganisms was found in a single sample. In conclusion, we were able to determine the microbiomes of various mixed cultures used to produce beer, providing useful information to better understand the sour beer fermentation process and brewing techniques.