Multi-Elemental Analysis of Hair and Fingernails Using Energy-Dispersive X-ray Fluorescence (ED XRF) Method Supported by Inductively Coupled Plasma Mass Spectrometry (ICP MS).

This work compared the multi-element analysis of human hair and nails using inductively coupled plasma mass spectrometry (ICP MS) with an easy, fast, cheap, non-destructive method using energy-dispersive x-ray fluorescence (ED XRF). The ICP MS-based method was more sensitive (over 30 elements could be quantified) and costly (requiring more time, samples, and chemicals). The EDX-based method required laboratory and certified reference materials made of hair for instrument calibration. It was less sensitive (16 elements could be quantified: S, Si, Ca, Br, Fe, Cu, Cr, Mg, Si, K, Mn, Ni, Zn, Se, Sr, Pb), but it allowed us to replace troublesome grinding with the dissolution of keratin-based material with an alkalic agent (tetramethylammonium hydroxide, TMAH) and the formation of stable-for-days pellets. This method is simple, enables automation, and, due to the modification of wells in the autosampler of the EDX system via the immersion of home-designed inserts, it requires smaller amounts of biological material and binder (down to 70 mg instead of 500 mg required by commercially available instrument) to perform analysis. It was concluded that the EDX-based method offers complementary selectivity and sensitivity to ICP MS with the possibility of sample reuse for further analysis.

Polish publications on jujutsu (1906-2020): bibliometric analysis / Publicações polonesas sobre jiu-jítsu (1906-2020): análise bibliométrica / Publicaciones polacas sobre jujutsu (1906-2020): análisis bibliométrico

Abstract The aim was to perform a bibliometric analysis of Polish jujutsu publications focused on productivity, topics, and collaboration. Thus, the National Library of Poland, Polish Scientific Journals Database, Web of Science and Scopus were consulted. Results were filtered and exported to Excel 2016 for statistical analysis. 123 Polish jujutsu documents were published from 1906 to 2020. Life Sciences had the highest representation, while collaboration predominated during the last decade. Cynarski was the most productive author, while Wojdat achieved the highest collaboration index. Ido Movement for Culture was the main source for disseminating these publications. In conclusion, technical books written by single authors from a Life Sciences approach prevailed in Polish jujutsu publications during the 20th century, while scientific articles written in collaboration and also representing other approaches have prevailed in the 21st century.

Resumo O objetivo foi realizar uma análise bibliométrica das publicações polonesas sobre jiu-jítsu com foco nos aspectos de produtividade, assuntos e colaboração. Assim, a Biblioteca Nacional da Polônia, a Base de Revistas Científicas Polonesas, Web of Science e Scopus foram consultados. Os resultados foram filtrados e exportados para o Excel 2016 para análise estatística. Os documentos poloneses sobre jiu-jítsu chegaram a 123 publicados entre 1906 e 2020. Ciências da Vida foi o campo mais representado, enquanto a colaboração prevaleceu durante a última década. Cynarski foi o autor mais produtivo, enquanto Wojdat teve a maior taxa de colaboração. Ido Movement for Culture foi o principal divulgador dessas publicações. Em conclusão, as publicações polonesas sobre jiu-jítsu mostraram durante o século XX uma predominância de livros técnicos escritos por autores individuais a partir de uma abordagem das Ciências da Vida, enquanto os artigos científicos escritos em colaboração e também representando outras abordagens dominaram o século XXI.

Resumen El objetivo fue realizar un análisis bibliométrico de las publicaciones polacas sobre jujutsu centrado en los aspectos de productividad, asuntos y colaboración. Así, se consultaron la Biblioteca Nacional de Polonia, la Base de Revistas Científicas Polacas, la Web of Science y Scopus. Los resultados fueron filtrados y exportados a Excel 2016 para el análisis estadístico. Los documentos polacos sobre jujutsu alcanzaron los 123, publicados entre 1906 y 2020. Ciencias de la Vida fue el campo más representado, mientras que la colaboración predominó durante la última década. Cynarski fue el autor más productivo, mientras que Wojdat obtuvo el índice de colaboración más alto. Ido Movement for Culture fue el principal divulgador de estas publicaciones. En conclusión, las publicaciones polacas sobre jujutsu mostraron, durante el siglo XX, un predominio de libros técnicos escritos por autores individuales desde un abordaje de las Ciencias de la Vida, mientras que los artículos científicos escritos en colaboración y representando también otros enfoques han dominado en el siglo XXI.

NMR Spin-Spin Coupling Constants Derived from Relativistic Four-Component DFT Theory-Analysis and Visualization.

An unambiguous assignment of coupling pathways plays an important role in the description and rationalization of NMR indirect spin-spin coupling constants (SSCCs). Unfortunately, the SSCC analysis and visualization tools currently available to quantum chemists are restricted to nonrelativistic theory. Here, we present the theoretical foundation for novel relativistic SSCC visualization techniques based on analysis of the SSCC densities and the first-order current densities induced by the nuclear magnetic dipole moments. Details of the implementation of these techniques in the ReSpect program package are discussed. Numerical assessments are performed on through-space SSCCs, and we choose as our examples the heavy-atom Se-Se, Se-Te, and Te-Te coupling constants in three similar molecules for which experimental data are available. SSCCs were calculated at the nonrelativistic, scalar relativistic, and four-component relativistic density functional levels of theory. Furthermore, with the aid of different visualization methods, we discuss the interpretation of the relativistic effects, which are sizable for Se-Se, very significant for Se-Te, and cannot be neglected for Te-Te couplings. A substantial improvement of the theoretical SSCC values is obtained by also considering the molecular properties of a second conformation.

Stereocontrolled Debenzylative Cycloetherification Reaction as a Route to Enantiopure C-Furanosides with Amino Substituents in the Side Chain.

A highly efficient methodology of the preparation of synthetically important tetrahydrofuran derivatives with an amino substituent in the side chain is reported. This process is based on the stereocontrolled debenzylative cycloetherification (DBCE) reaction applied for chirons from the d-gluco- and d-manno-series and provides derivatives with new stereogenic centers. The influence of the electron-withdrawing group (EWG), present in the acyclic substrates with the mesyl leaving group, on the reactivity in the DBCE reaction was investigated both "in the flask" and by density functional theory (DFT) calculations. It was demonstrated that tetrahydrofuran derivatives with the benzoxime group (EWG = CHNOBn) are very good candidates for the subsequent highly stereoselective Grignard reaction.

Calculation of NMR Spin-Spin Coupling Constants in Strychnine.

We compare the NMR indirect nuclear spin-spin coupling constants in strychnine calculated using density functional theory (DFT) with the semiempirical relativistic force field (RFF) method of Kutateladze and Mukhina (KM) (J. Org. Chem. 2015, 80, 10838-10848). DFT values significantly more accurate than those obtained by KM for their comparison with RFF values can be obtained, at a lower cost, by an appropriate selection of basis set.

The role of steric hindrance in the intramolecular oxidative aromatic coupling of pyrrolo[3,2-b]pyrroles.

The presence of steric hindrance triggers different reaction pathways in the intramolecular oxidative aromatic coupling of tetraaryl-pyrrolo[3,2-b]pyrroles and leads to the formation of a fluorene moiety and a new cationic π-system linked together by a spiro carbon atom. Computational studies elegantly rationalized these results. These previously unknown functional dyes emit red light with reasonable efficiency.

Reactions of stabilized aliphatic carbanions with esters of formic acid in the gas phase.

The reactions of nitromethane, acetonitrile, and ethyl acetate carbanions with formic acid esters were investigated in the gas phase by mass spectrometry and quantum chemical calculations. It was found that the carbanion of nitromethane practically does not react with formic acid esters and only traces of the Claisen- type addition-elimination reaction product were observed. In the case of the deprotonated acetonitrile, the Claisen-type condensation that yielded the carbanion of cyanoacetaldehyde proceeded almost quantitatively for all the studied formates. Other products, like the Riveros reaction product, were observed in minor amounts. The ethyl acetate carbanion reacts with formates in a much more complex way because it decomposes in a collision cell, yielding the deprotonated ketene anion, which also can react with formic acid esters. Consequently, the Claisen condensation reaction products of both anions were observed as well as the products of other reactions. All the proposed reaction pathways were confirmed by quantum chemical calculations, including the transition-state energies.

Addition-elimination versus Tishchenko reaction in the gas phase.

Gas phase reactions of the substituted phenide ions with methyl formate have been studied. It was found that the results of these reactions depend mainly on the basicity of the phenide ion, which is related to the presence of the electron-accepting or electron-donating substituents in the benzene ring. It was shown that the phenide ions substituted with electron-withdrawing groups react with methyl formate in the gas phase in a two-step reaction. The first step that proceeds according to the typical addition-elimination mechanism results in the formation of the anion of the respective benzaldehyde derivative with the negative charge located either in the aldehyde group (acyl anion) or in the benzene ring (phenide anion) in position ortho to an aldehyde moiety. In the second step, the preliminary-formed anion reacts with the second molecule of methyl formate yielding formally product of the second addition-elimination reaction. Theoretical calculations as well as collision induced dissociation spectra of the model compounds suggest that this reaction proceeds according to the Tishchenko reaction mechanism yielding the respective phthalide anion. According to our knowledge, this is the first example of the Tishchenko-type reaction in the gas phase.

Comparison of the sensitivity of mass spectrometry atmospheric pressure ionization techniques in the analysis of porphyrinoids.

The porphyrinoids chemistry is greatly dependent on the data obtained in mass spectrometry. For this reason, it is essential to determine the range of applicability of mass spectrometry ionization methods. In this study, the sensitivity of three different atmospheric pressure ionization techniques, electrospray ionization, atmospheric pressure chemical ionization and atmospheric pressure photoionization, was tested for several porphyrinods and their metallocomplexes. Electrospray ionization method was shown to be the best ionization technique because of its high sensitivity for derivatives of cyanocobalamin, free-base corroles and porphyrins. In the case of metallocorroles and metalloporphyrins, atmospheric pressure photoionization with dopant proved to be the most sensitive ionization method. It was also shown that for relatively acidic compounds, particularly for corroles, the negative ion mode provides better sensitivity than the positive ion mode. The results supply a lot of relevant information on the methodology of porphyrinoids analysis carried out by mass spectrometry. The information can be useful in designing future MS or liquid chromatography-MS experiments.

Mass spectrometry studies on meso-substituted corroles and their photochemical decomposition products.

Corroles, ring-contracted analogs of porphyrins, are an important class of compounds which have attracted the attention of many researchers in the fields of organic, coordination and physical chemistry. In the present work, the stability and the decomposition pathways of a diverse set of meso-substituted corroles have been studied using mass spectrometry (MS), UV-Vis absorption and preparative methods combined with NMR spectroscopy. Four different ionization methods (electrospray ionization, field desorption, atmospheric pressure photoionization and atmospheric pressure chemical ionization) were utilized to investigate light- and oxygen-induced decomposition in various solvents. It was found that the rate of decomposition in MeCN is significantly higher than in CH(2)Cl(2), hexane, MeOH and ethyl acetate. HR-MS combined with CID-MS/MS enabled us to identify the products of initial decomposition. Surprisingly, numerous smaller open-chain compounds were also detected. Large-scale decomposition of a corrole bearing sterically hindered substituents at positions 5 and 15 allowed us to isolate mg quantities of three decomposition products: isocorrole and isomeric biliverdin-type species. These are formed as a result of oxygen attack on the meso-10 position.