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Cobalt nanoparticles with diameters of 8 nm have recently shown promising performance for biomedical applications. However, it is still unclear how the shape of cobalt clusters changes with size when reaching the nanoparticle range. In the present work, density functional theory calculations have been employed to compare the stabilities of two non-crystalline (icosahedron and decahedron) shapes, and three crystalline motifs (hcp, fcc, and bcc) for magic numbered cobalt clusters with up to 1500 atoms, based on the changes in the cohesive energies, coordination numbers, and nearest-neighbour distances arising from varying geometries. Obtained trends were extrapolated to a 104 size range, and an icosahedral shape was predicted for clusters up to 5500 atoms. Larger sized clusters adopt hcp stacking, in correspondence with the bulk phase. To explain the crystalline/non-crystalline crossovers, the contributions of the elastic strain density and twin boundary from the specimen surfaces to the cohesive energy of different motifs were evaluated. These results are expected to aid the design and synthesis of cobalt nanoparticles for applications ranging from catalysis to biomedical treatments.

Owing to their high saturation magnetisation, cobalt nanoparticles hold significant potential for the hyperthermia treatment of tumours. Covalent binding of carboxylic acids to the nanoparticles can induce biocompatibility, whilst also preventing the formation of surface oxides which reduce the magnetic properties of cobalt. Understanding the origin of the acid-metal interaction is key, yet probably the most experimentally challenging step, for the rational design of such entities. In this density functional theory study, we use static calculations to establish that a 57-atom Co cluster is the smallest model able to reproduce the adsorption behaviour of carboxylic acids, and ab initio metadynamics to obtain the structure and the free energy landscape for its interaction with valeric acid. Our simulations show that a bridging bidentate binding mode has a stronger affinity compared to monodentate binding, with energetically high transition barriers between the two. A chelate interaction mode of two carboxyl oxygen atoms can be formed as an intermediate. These results clarify the organic-inorganic interactions in the cobalt-acid system, providing a basis for the rational design of biocompatible metallic nanoparticles.

Binary II-V semiconductors are highly optically active materials, possess high intrinsic mechanical and chemical durability, and have electronic properties ideal for optoelectronic applications. Among them, zinc diphosphide (ZnP2) is a promising earth-abundant absorber material for solar energy conversion. We have investigated the structural, mechanical, and optoelectronic properties of both the tetragonal (α) and monoclinic (β) phases of ZnP2 using standard, Hubbard-corrected and screened hybrid density functional theory methods. Through the analysis of bond character, band gap nature, and absorption spectra, we show that there exist two polymorphs of the β phase (denoted as β 1 and β 2) with distinct differences in the photovoltaic potential. While β 1 exhibits the characteristics of metallic compounds, β 2 is a semiconductor with predicted thin-film photovoltaic absorbing efficiency of almost 10%. The α phase is anticipated to be an indirect gap material with a calculated efficiency limited to only 1%. We have also analysed and gained insights into the electron localization function, projected density of states and projected crystal orbital Hamilton populations for the analogue bonds between the α and β-ZnP2. In light of these calculations, a number of previous discrepancies have been solved and a solid ground for future employment of zinc diphosphides in photovoltaics has been established.

Biomolekule su iznimno važan dio svakoga organizma jer kontroliraju gotovo sve njegove aspekte, od strukture do životnih procesa i energije. Stoga posljednjih godina velik broj analitičara usmjerava pažnju upravo na unaprjeđenje postojećih i razvoj novih metoda i instrumentacije koja će omogućiti analizu biomolekula i dodatno razumijevanje njihovih uloga. Jedna od zastupljenijih metoda za analizu i odvajanje različitih nabijenih ili ionizirajućih molekula poput aminokiselina, proteina ili ugljikohidrata je ionska kromatografija. Ova metoda odlikuje se brojnim pogodnostima kao što su primjenjivost za simultanu analizu velikog broja molekula, lako povezivanje s drugim tehnikama (primjerice tehnikama detekcije), a u funkciji pročišćavanja omogućava dobivanje izrazito čistih proizvoda u relativno kratkom vremenu izvođenja. Velik napredak u analizi aminokiselina i ugljikohidrata bilo je uvođenje pulsne amperometrijske detekcije. Pregledom literature pronađene su brojne aplikacije za učinkovito i simultano razdvajanje i određivanje aminokiselina i ugljikohidrata anionskim izmjenjivačkim kolonama uz integriranu pulsnu amperometrijsku detekciju. Ovaj rad nudi pregled aktualnih metoda analize aminokiselina i ugljikohidrata s detaljnijim osvrtom na pronađene kromatografske aplikacije. Biomolecules are an extremely important part of every single organism since they control almost all of its aspects, from structure to metabolic processes and transformation of energy. Because of that, recent researches are driven towards the improvement of existing methods or development of the new ones, followed by development of instrumentation which will make analysis and understanding of biomolecules and the roles they have in organisms easier. Ion chromatography is one of the most intensively used methods in the analysis of biomolecules such as amino acids, proteins or carbohydrates. This method has a vast variety of advantages which includes simultaneous analysis of a huge number of molecules, simple linkage with other techniques (detection techniques, for example), and, in the purification mode, final products are extremely pure and obtained in short run time. Great progress has been made in the analysis of amino acids and carbohydrates when pulsed amperometric detection was introduced. By reviewing the literature, many applications have been found for the effective and simultaneous separation and determination of amino acids and carbohydrates on anion exchange columns with integrated pulsed amperometric detection. This manuscript is a review that summarises current methods for the analysis of amino acids and carbohydrates with emphasis on chromatographic techniques.

Ion chromatography is one of the most intensively used methods for analysis of biomolecules such as amino acids and carbohydrates. Generally, this includes gradient separation on anion exchange resin followed by pulse amperometric detection. Gradient and pulse profile has to be optimized in order to obtain good quality results. Presence of the natural matrix makes method development even more complex process. This lecture review and summarizes current methods for the analysis of amino acids and carbohydrates. Several examples will be presented including fermentation broth, cell cultures and tea revealing key factors within method development process.