Disclosing Interfaces of ZnO Nanocrystals Using Dynamic Nuclear Polarization: Sol‐Gel versus Organometallic Approach

The unambiguous characterization of the coordination chemistry of nanocrystal surfaces produced by wet‐chemical synthesis presently remains highly challenging. Here, zinc oxide nanocrystals (ZnO NCs) coated by monoanionic diphenyl phosphate (DPP) ligands were derived by a sol‐gel process and a one‐pot self‐supporting organometallic (OSSOM) procedure. Atomic‐scale characterization through dynamic nuclear polarization (DNP‐)enhanced solid‐state NMR (ssNMR) spectroscopy has notably enabled resolving their vastly different surface‐ligand interfaces. For the OSSOM‐derived NCs, DPP moieties form stable and strongly‐anchored μ₂‐ and μ₃‐bridging‐ligand pairs that are resistant to competitive ligand exchange. The sol‐gel‐derived NCs contain a wide variety of coordination modes of DPP ligands and a ligand exchange process takes place between DPP and glycerol molecules. This highlights the power of DNP‐enhanced ssNMR for detailed NC surface analysis and of the OSSOM approach for the preparation of ZnO NCs.     

The Role of Serotonin Neurotransmission in Gastrointestinal Tract and Pharmacotherapy

5-Hydroxytryptamine (5-HT, serotonin) is a neurotransmitter in both the central nervous system and peripheral structures, acting also as a hormone in platelets. Although its concentration in the gut covers >90% of all organism resources, serotonin is mainly known as a neurotransmitter that takes part in the pathology of mental diseases. Serotonin modulates not only CNS neurons, but also pain transmission and platelet aggregation. In the periphery, 5-HT influences muscle motility in the gut, bronchi, uterus, and vessels directly and through neurons. Serotonin synthesis starts from hydroxylation of orally delivered tryptophan, followed by decarboxylation. Serotonin acts via numerous types of receptors and clinically plays a role in several neural, mental, and other chronic disorders, such as migraine, carcinoid syndrome, and some dysfunctions of the alimentary system. 5-HT acts as a paracrine hormone and growth factor. 5-HT receptors in both the brain and gut are targets for drugs modifying serotonin neurotransmission. The aim of the present article is to review the 5-HT receptors in the gastrointestinal (GI) tract to determine the role of serotonin in GI physiology and pathology, including known GI diseases and the role of serotonin in GI pharmacotherapy.     

Is human hair a proper 210Po and 210Pb monitor of their increased activity in the human body?

Journal of Radioanalytical and Nuclear Chemistry - The study focused on 210Po and 210Pb activity concentrations determination in human hair as well as investigation its utility as an easy and safe...     

Selection of Suitable Methods for the Detection of Microplastics in the Environment

Journal of Analytical Chemistry - Microplastics (MPs) currently cause an environmental risk due to their transport to all components of the environment. The review article aims to evaluate and...     

Radiation synthesis of silver nanostructures in cotton matrix

Cotton is one of the most popular natural fibres, composed mainly of cellulose, which finds a wide range of applications in paper, textile and health care products industry. Researchers have focused their interest on the synthesis of cotton nanocomposites, which enhances its mechanical, thermal and antimicrobial properties by the incorporation of various nanoparticles into the cotton matrix. Silver is one of the most popular antimicrobial agents with a wide spectrum of antibacterial and antifungal activity that results from a complex mechanism of its interactions with the cells of harmful microorganism. In this work, electron beam radiation was applied to synthesise silver nanostructures in cotton fibres. Investigations of the influence of the initial silver salt concentration on the size and distribution of the obtained silver nanostructures were carried out. A detailed characterisation of these nanocomposites with SEM-BSE and EDS methods was performed. TGA and DSC analyses were performed to assess the influence of different size silver nanoparticles and the effect of electron beam irradiation on the thermal properties of cotton fibres. A microbiological investigation to determine the antibacterial activity of Ag-cotton nanocomposites was carried out.     

Plutonium fractionation in southern Baltic Sea sediments

In this study, different chemical plutonium fractions (dissolved in water, connected to carbonates, connected to oxides, complexed with organic matter, mineral acids soluble and the rest) in sediments from the Vistula River estuary, the Gdańsk Basin and the Bornholm Deep were determined. The distribution of (239+240)Pu in analysed sediments samples was not uniform but dependent on its chemical form, depth and the sediment geomorphology. The highest amount of plutonium exists in middle parts of sediments and comes from the global atmospheric fallout from nuclear tests in 1958-1961. According to all analysed fractions, the biggest amount of (239+240)Pu was in the mobile form, connected to carbonate fractions from the Vistula River estuary, the Gulf of Gdańsk and the Bornholm Deep sediments.     

1,4-Diazaspiro[2.2]pentanes as a flexible platform for the synthesis of diamine-bearing stereotriads

Nitrogen-containing stereotriads occur in a number of biologically active compounds, but general and flexible methods to access these compounds are limited mainly to the manipulation of chiral olefins. An alternative approach is to employ a highly chemo-, regio-, and stereocontrolled allene oxidation that can install a new carbon-heteroatom bond at each of the three original allene carbons. In this paper, an intramolecular/intermolecular allene bis-aziridination is described that offers the potential to serve as a key step for the construction of stereotriads containing vicinal diaminated motifs. The resultant 1,4-diazaspiro[2.2]pentane (DASP) scaffolds contain two electronically differentiated aziridines that undergo highly regioselective ring openings at C1 with a variety of heteroatom nucleophiles to give chiral N,N-aminals. Alternatively, the same DASP intermediate can be induced to undergo a double ring-opening reaction at both C1 and C3 to yield vicinal diaminated products corresponding to formal ring opening at C3. The chirality of a propargyl alcohol is easily transferred to the DASP with good fidelity, providing a new paradigm for the construction of enantioenriched nitrogen-containing stereotriads.