Controlling the europium oxidation state in diopside through flux concentration

This paper explores the connection between the H3BO3 flux concentration and the co-existence of Eu2+ and Eu3+ dopants within CaMgSi2O6 crystals (diopside). The samples were synthesised using a solid-state synthesis method under varying atmospheric conditions, including oxidative (air), neutral (N2), and reductive (H2/N2 mixture) environments. Additionally, some materials underwent chemical modification by partially substituting Si4+ with Al3+ ions acting as charge compensation defects stabilizing Eu3+ luminescence. Depending on the specific synthesis conditions, the materials predominantly displayed either the orange-red luminescence of Eu3+ (under oxidising conditions) or the blue luminescence of Eu2+; however, the comprehensive results confirmed the co-existence of Eu3+/Eu2+ luminescence in both cases. This work shows that varying flux concentrations added during synthesis significantly affect the relative strength of Eu2+ and Eu3+ emissions in a manner dependent on the synthesis atmosphere. The emission of Eu2+ increases with a higher flux concentration in materials synthesised under oxidative and neutral atmospheres independent of the chemical modification. In contrast, for materials obtained under a reductive atmosphere, the changes in the Eu3+ emission intensity depended on the presence or absence of Al3+ ions namely the increase of flux increased the Eu3+ intensity in the case of unmodified materials and decreased in the Al-modified ones. All observed effects were qualitatively explained considering the double role of the flux in the studied system, which besides facilitating the diffusion of chemical species during synthesis acts as a charge compensating agent by creating B'Si centres stabilizing Eu3+ emission.

The new method of ZnIn2S4 synthesis on the titania nanotubes substrate with enhanced stability and photoelectrochemical performance

In this work, ZnIn2S4 layers were obtained on fluorine doped tin oxide (FTO) glass and TiO2 nanotubes (TiO2NT) using a hydrothermal process as photoanodes for photoelectrochemical (PEC) water splitting. Then, samples were annealed and the effect of the annealing temperature was investigated. Optimization of the deposition process and annealing of ZnIn2S4 layers made it possible to obtain an FTO-based material generating a photocurrent of 1.2 mA cm-2 at 1.62 V vs. RHE in a neutral medium. In contrast, the highest photocurrent in the neutral electrolyte obtained for the TiO2NT-based photoanode reached 0.5 mA cm-2 at 1.62 V vs. RHE. In addition, the use of a strongly acidic electrolyte allowed the generated photocurrent by the TiO2NT-based photoanode to increase to 3.02 mA cm-2 at 0.31 V vs. RHE. Despite a weaker photoresponse in neutral electrolyte than the optimized FTO-based photoanode, the use of TiO2NT as a substrate allowed for a significant increase in the photoanode's operating time. After 2 h of illumination, the photocurrent response of the TiO2NT-based photoanode was 0.21 mA cm-2, which was 42% of the initial value. In contrast, the FTO-based photoanode after the same time generated a photocurrent of 0.02 mA cm-2 which was only 1% of the initial value. The results indicated that the use of TiO2 nanotubes as a substrate for ZnIn2S4 deposition increases the photoanode's long-term stability in photoelectrochemical water splitting. The proposed charge transfer mechanism suggested that the heterojunction between ZnIn2S4 and TiO2 played an important role in improving the stability of the material by supporting charge separation.

Lanthanide ions (Eu3+, Er3+, Pr3+) as luminescence and charge carrier centers in Sr2TiO4

A series of strontium orthotitanate (Sr₂TiO₄) samples doped with 2% of a mole of europium, praseodymium, and erbium were obtained using the solid-state synthesis method. The X-ray diffraction (XRD) technique confirms the phase purity of all samples and the lack of the influence of dopants at a given concentration on the structure of materials. The optical properties indicate, in the case of Sr₂TiO₄:Eu³⁺, two independent emission (PL) and excitation (PLE) spectra attributed to the Eu³⁺ ions at sites with different symmetries: low - excited at 360 nm and high - excited at 325 nm, while, for Sr₂TiO₄:Er³⁺ and Sr₂TiO₄:Pr³⁺, the emission spectra do not depend on the excitation wavelength. The measurements of X-ray photoemission spectroscopy (XPS) indicate the presence of only one type of charge compensation mechanism, which is based on the creation of strontium vacancies in all cases. This suggests that the different charge compensation mechanisms cannot easily explain the presence of Eu³⁺ at two non-equivalent crystal sites. The photocurrent excitation (PCE) spectroscopy investigations, that have not been reported in the literature so far, show that among all the studied dopants, only Pr³⁺ can promote the electrons to the conduction band and give rise to electron conductivity. The results collected from the PLE and PCE spectra allowed us to find the location of the ground states of lanthanides(II)/(III) in the studied matrix.

Multiomic atlas with functional stratification and developmental dynamics of zebrafish cis-regulatory elements

Zebrafish, a popular organism for studying embryonic development and for modeling human diseases, has so far lacked a systematic functional annotation program akin to those in other animal models. To address this, we formed the international DANIO-CODE consortium and created a central repository to store and process zebrafish developmental functional genomic data. Our data coordination center ( https://danio-code.zfin.org ) combines a total of 1,802 sets of unpublished and re-analyzed published genomic data, which we used to improve existing annotations and show its utility in experimental design. We identified over 140,000 cis-regulatory elements throughout development, including classes with distinct features dependent on their activity in time and space. We delineated the distinct distance topology and chromatin features between regulatory elements active during zygotic genome activation and those active during organogenesis. Finally, we matched regulatory elements and epigenomic landscapes between zebrafish and mouse and predicted functional relationships between them beyond sequence similarity, thus extending the utility of zebrafish developmental genomics to mammals.

Fasciola hepatica Fatty Acid Binding Protein 1 Modulates T cell Polarization by Promoting Dendritic Cell Thrombospondin-1 Secretion Without Affecting Metabolic Homeostasis in Obese Mice

Background

The parasitic trematode Fasciola hepatica evades host immune defenses through secretion of various immunomodulatory molecules. Fatty Acid Binding Proteins (fhFABPs) are among the main excreted/secreted proteins and have been shown to display anti-inflammatory properties. However, little is currently known regarding their impact on dendritic cells (DCs) and their subsequent capacity to prime specific CD4+ T cell subsets.

Methodology/Principal Findings

The immunomodulatory effects of both native F. hepatica extracts and recombinant fhFABPs were assessed on monocyte-derived human DCs (moDCs) and the underlying mechanism was next investigated using various approaches, including DC-allogenic T cell co-culture and DC phenotyping through transcriptomic, proteomic and FACS analyses. We mainly showed that fhFABP1 induced a tolerogenic-like phenotype in LPS-stimulated moDCs characterized by a dose-dependent increase in the cell-surface tolerogenic marker CD103 and IL-10 secretion, while DC co-stimulatory markers were not affected. A significant decrease in secretion of the pro-inflammatory cytokines IL-12p70 and IL-6 was also observed. In addition, these effects were associated with an increase in both Th2-on-Th1 ratio and IL-10 secretion by CD4+ T cells following DC-T cell co-culture. RNA sequencing and targeted proteomic analyses identified thrombospondin-1 (TSP-1) as a non-canonical factor highly expressed and secreted by fhFABP1-primed moDCs. The effect of fhFABP1 on T cell skewing was abolished when using a TSP-1 blocking antibody during DC-T cell co-culture. Immunomodulation by helminth molecules has been linked to improved metabolic homeostasis during obesity. Although fhFABP1 injection in high-fat diet-fed obese mice induced a potent Th2 immune response in adipose tissue, it did not improved insulin sensitivity or glucose homeostasis.

Conclusions/Significance

We show that fhFABP1 modulates T cell polarization, notably by promoting DC TSP-1 secretion in vitro, without affecting metabolic homeostasis in a mouse model of type 2 diabetes.

Genomic and physiological analyses of the zebrafish atrioventricular canal reveal molecular building blocks of the secondary pacemaker region

The atrioventricular canal (AVC) is the site where key structures responsible for functional division between heart regions are established, most importantly, the atrioventricular (AV) conduction system and cardiac valves. To elucidate the mechanism underlying AVC development and function, we utilized transgenic zebrafish line sqet31Et expressing EGFP in the AVC to isolate this cell population and profile its transcriptome at 48 and 72 hpf. The zebrafish AVC transcriptome exhibits hallmarks of mammalian AV node, including the expression of genes implicated in its development and those encoding connexins forming low conductance gap junctions. Transcriptome analysis uncovered protein-coding and noncoding transcripts enriched in AVC, which have not been previously associated with this structure, as well as dynamic expression of epithelial-to-mesenchymal transition markers and components of TGF-β, Notch, and Wnt signaling pathways likely reflecting ongoing AVC and valve development. Using transgenic line Tg(myl7:mermaid) encoding voltage-sensitive fluorescent protein, we show that abolishing the pacemaker-containing sinoatrial ring (SAR) through Isl1 loss of function resulted in spontaneous activation in the AVC region, suggesting that it possesses inherent automaticity although insufficient to replace the SAR. The SAR and AVC transcriptomes express partially overlapping species of ion channels and gap junction proteins, reflecting their distinct roles. Besides identifying conserved aspects between zebrafish and mammalian conduction systems, our results established molecular hallmarks of the developing AVC which underlies its role in structural and electrophysiological separation between heart chambers. This data constitutes a valuable resource for studying AVC development and function, and identification of novel candidate genes implicated in these processes.

Exploring Translational Control of Maternal mRNAs in Zebrafish

The study of translational regulation requires reliable measurement of both mRNA levels and protein synthesis. Cytoplasmic polyadenylation is a prevalent mode of translational regulation during oogenesis and early embryogenesis. Here the length of the poly(A) tail of an mRNA is coupled to its translatability. We describe a protocol to identify translationally regulated genes and measure their translation rate in the early zebrafish embryo using genome-wide polysome profiling. This protocol relies on the isolation of mRNA by means of an rRNA depletion strategy, which avoids capture bias due to short poly(A) tail that can occur when using conventional oligo(dT)-based methods. We also present a simple PCR-based method to measure the poly(A) tail length of selected mRNAs.

A novel conserved enhancer at zebrafish zic3 and zic6 loci drives neural expression

Background

Identifying enhancers and deciphering their putative roles represent a major step to better understand the mechanism of metazoan gene regulation, development, and the role of regulatory elements in disease. Comparative genomics and transgenic assays have been used with some success to identify critical regions that are involved in regulating the spatiotemporal expression of genes during embryogenesis.

Results

We identified two novel tetrapod‐teleost conserved noncoding elements within the vicinity of the zic3 and zic6 loci in the zebrafish genome and demonstrated their ability to drive tissue‐specific expression in a transgenic zebrafish assay. The syntenic analysis and robust green fluorescent expression in the developing habenula in the stable transgenic line were correlated with known sites of endogenous zic3 and zic6 expression.

Conclusion

This transgenic line that expresses green fluorescent protein in the habenula is a valuable resource for studying a specific population of cells in the zebrafish central nervous system. Our observations indicate that a genomic sequence that is conserved between humans and zebrafish acts as an enhancer that likely controls zic3 and zic6 expression.

Identified a novel enhancer near zebrafish zic3/zic6 locus.

The novel enhancer drives tissue‐specific expression in the habenula.

Zebrafish transgenic line generated in this study can be a useful resource for studying development of habenula.

Cytoplasmic polyadenylation-mediated translational control of maternal mRNAs directs maternal-to-zygotic transition

In the earliest stages of animal development following fertilization, maternally deposited mRNAs direct biological processes to the point of zygotic genome activation (ZGA). These maternal mRNAs undergo cytoplasmic polyadenylation (CPA), suggesting translational control of their activation. To elucidate the biological role of CPA during embryogenesis, we performed genome-wide polysome profiling at several stages of zebrafish development. Our analysis revealed a correlation between CPA and polysome-association dynamics, demonstrating a coupling of translation to the CPA of maternal mRNAs. Pan-embryonic CPA inhibition disrupted the maternal-to-zygotic transition (MZT), causing a failure of developmental progression beyond the mid-blastula transition and changes in global gene expression that indicated a failure of ZGA and maternal mRNA clearance. Among the genes that were differentially expressed were those encoding chromatin modifiers and key transcription factors involved in ZGA, including nanog, pou5f3 and sox19b, which have distinct CPA dynamics. Our results establish the necessity of CPA for ensuring progression of the MZT. The RNA-seq data generated in this study represent a valuable zebrafish resource for the discovery of novel elements of the early embryonic transcriptome.

Mammalian cell defence mechanisms against the cytotoxicity of NaYF4:(Er,Yb,Gd) nanoparticles

Water-soluble upconversion nanoparticles (UCNPs), based on polyvinylpyrrolidone (PVP)-coated NaYF₄:Er³⁺,Yb³⁺,Gd³⁺, with various concentrations of Gd³⁺ ions and relatively high upconversion efficiencies, were synthesized. The internalization and cytotoxicity of the thus obtained UCNPs were evaluated in three cell lines (HeLa, HEK293 and astrocytes). No cytotoxicity was observed even at concentrations of UCNPs up to 50 μg ml^-1. The fate of the UCNPs within the cells was studied by examining their upconversion emission spectra with confocal microscopy and confirming these observations with transmission electron microscopy. It was found that the cellular uptake of the UCNPs occurred primarily by clathrin-mediated endocytosis, whereas they were secreted from the cells via lysosomal exocytosis. The results of this study, focused on the mechanisms of the cellular uptake, localization and secretion of UCNPs, demonstrate, for the first time, the co-localization of UCNPs within discrete cell organelles.

Vaccination with a cocktail of Ancylostoma ceylanicum recombinant antigens leads to worm burden reduction in hamsters

Hookworms, a group to which Ancylostoma ceylanicum belongs, are gastrointestinal nematodes that infect more than 700 million people around the world. They are a leading cause of anemia in developing countries. In order to effectively prevent hookworm infections research is conducted to develop an effective vaccine using recombinant antigens of the parasite. The aim of this study was to examine the influence of the hosts' on protection against ancylostomiasis and the shaping of the humoral immune response among Syrian hamsters after immunization with a cocktail of five A. ceylanicum recombinant antigens. Ace-ASP-3, Ace-ASP-4, Ace-APR-1, Ace-MEP-6 and Ace-MEP-7 were obtained in the pET expression system. Immunization with a vaccine cocktail resulted in a 33.5% worm burden reduction. The immunogenicity of the recombinant proteins were determined using ELISA. Statistical analysis showed that vaccinated hamsters developed stronger humoral responses to four of five recombinant antigens (the exception being Ace-ASP-3) compared to hamsters from the control group.

The influence of nanostructure size on V2O5electrochemical properties as cathode materials for lithium ion batteries

The influence of the V₂O₅nanostructure size on the aggregation process and their electrochemical properties.

Upconverting/magnetic: Gd2O3:(Er3+,Yb3+,Zn2+) nanoparticles for biological applications: effect of Zn2+ doping

Upconverting/paramagnetic Gd₂O₃:1% Er³⁺, 18% Yb³⁺ with Zn²⁺ nanoparticles (NPs) permits one to perform optical imaging.

Application of mechanical and manual sutures enclosing the bronchus

The mechanical suture was introduced into thoracic surgical procedures by Amonosow and Androsow, Soviet surgeons, in the late 50s. The aim of the paper is to compare the incidence of bronchopleural fistulae that develop after the mechanical suture has been applied in bronchus surgery with the corresponding figures for traditional manual sutures. In the period of January 1997-March 1999 a series of 524 anatomical lung parenchyma resections was performed at the Department of Thoracic Surgery, Medical Academy of Gdańsk. In 460 cases (87.8%) the indication for the procedure came from primary lung carcinoma, and in 64 cases (12.2%) from tuberculosis, hamartoma, arteriovenous fistula, inflammatory lesions, asperpilloma, and metastases to the lungs. Depending on the way the bronchus was surgically closed the patients were subgrouped as follows: group I comprised 209 subjects (40.6%) whose bronchus was closed with a mechanical TA Premium Auto Suture, and group II that embraced 306 subjects (59.4%) whose bronchus was closed with a manual PDS 3/0 or Maxon 3/0 suture. The bronchopleural fistula developed in 11 cases of which 5/216 (2.3%) had the bronchus stump closed with a mechanical suture, and 6/308 (2.0%) cases had it closed with a manual suture. Of 11 cases of bronchopleural fistula 10 cases were noted after pneumonectomy. After the right side pneumonectomy, one fistula was discovered following the application of mechanical suture and six fistulas were found when the manual suture was used. After the left side pneumonectomy, no fistulae were discovered when the manual suture was used, and 3 those found were exclusively present when the mechanical suture was applied.