Proton Transfer Chemistry in the Gas Phase. Is a Spontaneous \u27Neutralization\u27 Reaction a Myth or a Reality?

Relying on physicochemical knowledge, the proton cannot be spontaneously transferred from a gaseous mineral acid (HF, HCl, HBr, HI, HNO3, H2SO4, or HClO4) to a gaseous nitrogen base (NH3, alkylamine, aniline, pyridine, amidine, or guanidine). For example, the full proton-transfer from HCl to NH3, followed by the separation of Cl- and NH4+ requires more than 500 kJ mol-1. The same is true for a spontaneous intramolecular proton-transfer for gaseous amino acids, aminophenols and other amphiprotic compounds. From the gas-phase acidity parameter of COOH and the gas-phase basicity parameter of NH2 (or other more basic group in the side chain), it appears that proton transfer is endothermic or endergonic. For arginine, an amino acid with a highly basic guanidine function, this difference is still larger than about 300 kJ mol-1. Only solvation of the acid-base system by neutral species (e.g., one or more water molecules), complexation by ions (e.g., ionic acids or bases, metal cations) or even electrons may reduce the energetic barrier and facilitate the proton-transfer. Recent extension of the gas-phase acidity-basicity scale toward superacids and superbases, and recent development of spectroscopic techniques adapted to the gas phase for less volatile organic compounds give some perspectives for observing the full intermolecular proton-transfer between a molecular Brønsted-Lowry superacid and a molecular Brønsted-Lowry superbase

Proton Transfer Chemistry in the Gas Phase. Is a Spontaneous \u27Neutralization\u27 Reaction a Myth or a Reality?

Relying on physicochemical knowledge, the proton cannot be spontaneously transferred from a gaseous mineral acid (HF, HCl, HBr, HI, HNO3, H2SO4, or HClO4) to a gaseous nitrogen base (NH3, alkylamine, aniline, pyridine, amidine, or guanidine). For example, the full proton-transfer from HCl to NH3, followed by the separation of Cl- and NH4+ requires more than 500 kJ mol-1. The same is true for a spontaneous intramolecular proton-transfer for gaseous amino acids, aminophenols and other amphiprotic compounds. From the gas-phase acidity parameter of COOH and the gas-phase basicity parameter of NH2 (or other more basic group in the side chain), it appears that proton transfer is endothermic or endergonic. For arginine, an amino acid with a highly basic guanidine function, this difference is still larger than about 300 kJ mol-1. Only solvation of the acid-base system by neutral species (e.g., one or more water molecules), complexation by ions (e.g., ionic acids or bases, metal cations) or even electrons may reduce the energetic barrier and facilitate the proton-transfer. Recent extension of the gas-phase acidity-basicity scale toward superacids and superbases, and recent development of spectroscopic techniques adapted to the gas phase for less volatile organic compounds give some perspectives for observing the full intermolecular proton-transfer between a molecular Brønsted-Lowry superacid and a molecular Brønsted-Lowry superbase

Integument cell gelatinisation : the fate of the integumentary cells in Hieracium and Pilosella (Asteraceae)

Members of the genera Hieracium and Pilosella are model plants that are used to study the mechanisms of apomixis. In order to have a proper understanding of apomixis, knowledge about the relationship between the maternal tissue and the gametophyte is needed. In the genus Pilosella, previous authors have described the specific process of the "liquefaction" of the integument cells that surround the embryo sac. However, these observations were based on data only at the light microscopy level. The main aim of our paper was to investigate the changes in the integument cells at the ultrastructural level in Pilosella officinarum and Hieracium alpinum. We found that the integument peri-endothelial zone in both species consisted of mucilage cells. The mucilage was deposited as a thick layer between the plasma membrane and the cell wall. The mucilage pushed the protoplast to the centre of the cell, and cytoplasmic bridges connected the protoplast to the plasmodesmata through the mucilage layers. Moreover, an elongation of the plasmodesmata was observed in the mucilage cells. The protoplasts had an irregular shape and were finally degenerated. After the cell wall breakdown of the mucilage cells, lysigenous cavities that were filled with mucilage were formed

Diagnostics for upper impacted canines – based on the literature

Impacted canines are the second most common (after the third molars) impacted teeth. Good diagnostics for impacted canines is possible at approx. 10 years of age, when the incorrect angulation of the crown of the tooth can be seen on the panoramic X-ray. The initial assessment of impacted canines includes a basic dental examination (presence of persistent deciduous teeth, lack of erupted permanent canines in the dental arch after the end of tooth eruption) and a palpative examination of alveolar bone in the vestibulum. The diagnostics is based mainly on X-rays: mainly panoramic images, tooth X-rays and occlusal plate pictures. The new tool in the diagnostics of impacted teeth is computed tomography, especially CBCT. The study collates diagnostic methods based primarily on panoramic X-ray images for the assessment and prediction of the spontaneous eruption chances of maxillary canines

Promotion of RES in a technology transfer network : case study of the Enterprise Europe Network

The promotion of renewable energy is a key concept in the European Union for both environmental and economic reasons. It contributes to securing the objectives set out in the Kyoto Protocol. In addition, it brings various social and economic benefits, e.g., diversification of the energy offer, new jobs, improvement of regional and local development opportunities and building a solid national industry. The main purpose of the article is to contribute to the debate on the instruments promoting renewable energy sources (RES) by emphasizing its importance within the technology transfer network. The subject is an empirical study of an actual technology transfer network. Its international activity promotes RES among entrepreneurs. Data related to meetings as part of brokerage events (BE) and company missions (CM) were subject to statistical and visual analysis, based on the data obtained from the Enterprise Europe Network from the years 2017-2018. The presented results are the foundation for future theoretical and practical studies. One of the important aspects to be examined is the intensity of cooperation launched during CM and BE. It is related to the results of partnership agreements and the importance of increasing the knowledge flow and creating opportunities for partners to acquire foreign technologies

Glucocorticoid-induced osteoporosis

Przewlekłe stosowanie glikokortykoidów jest najczęstszą przyczyną wtórnej osteoporozy. Około 30-50% chorych przyjmujących przewlekle kortykosteroidy doznaje złamań kręgów i odcinka bliższego kości udowej. Gwałtowne zmniejszenie gęstości mineralnej kości, nawet o 30%, oraz wzrost ryzyka złamań obserwuje się w ciągu pierwszych 6 miesięcy kortykosteroidoterapii, dlatego bardzo ważne jest wczesne wdrożenie odpowiedniego postępowania prewencyjnego. Przeważająca liczba chorych stosujących przewlekle glikokortykoidy nie jest właściwie leczona i monitorowana. Celem pracy było omówienie patofizjologii osteoporozy posteroidowej oraz przedstawienie aktualnych zaleceń dotyczących jej diagnostyki, prewencji i leczenia.Prolonged glucocorticoids administration is the most common cause of secondary osteoporosis. It is estimated that 30% to 50% of chronic glucocorticoids users experience vertebral or hip fractures. The highest bone loss (up to 30% in some studies) is observed in the first six months of treatment. Only a minority of patients who take chronic glucocorticoids receive optimal osteoporosis diagnosis, prevention, and/or treatment. The aim of this paper is to present the pathophysiology of glucocorticoid-induced osteoporosis, as well as some guidelines on diagnostic, preventive and therapeutic strategies for this disorder in an effort to promote the greater awareness of it

Place of vitamin D in everyday clinical practice — an interdisciplinary expert opinion

Niedobory witaminy D są jednymi z najczęściej występujących niedoborów w populacji ogólnej. Ich konsekwencje obejmują wiele układów, w tym krwionośny, kostno-stawowy, endokrynny i inne. Korygowanie niedoborów witaminy D może mieć niezwykle istotne znacznie w leczeniu wielu chorób i powinno być przedmiotem zainteresowania lekarzy wielu specjalności. Poniżej przedstawiono interdyscyplinarne stanowisko ekspertów dotyczące znaczenia witaminy D w patogenezie wielu jednostek chorobowych oraz zasadności uzupełniania jej niedoborów, bazujące na najnowszych doniesieniach i publikacjach.Vitamin D deficiency are among the most common deficiencies in the general population. Their consequences include many systems, including the circulatory, muscle and joints, endocrine and others. Correcting the deficiency of vitamin D can have extremely crucial impact on many diseases and should be of interest to doctors of many specialties. The following is a multi-disciplinary expert opinion on the significance of vitamin D in the pathogenesis of a number of diseases and their reasonableness supplement its deficiencies, based on the latest reports and publications

Quantum-chemical investigation of the structure and the antioxidant properties of α-lipoic acid and its metabolites

Quantum-chemical computations were used to investigate the structure–antioxidant parameter relationships of α-lipoic acid and its natural metabolites bisnorlipoic acid and tetranorlipoic acid in their oxidized and reduced forms. The enantiomers of lipoic and dihydrolipoic acid were optimized using the B3LYP/6-311+G(3df,2p), B3LYP/aug-cc-pVDZ and MP2(full)/6-31+G(d,p) levels of theory as isolated molecules and in the presence of water. The geometries of the metabolites and the values of their antioxidant parameters (proton affinity, bond dissociation enthalpy, adiabatic ionization potential, spin density, and the highest occupied molecular orbital energy) were calculated at the B3LYP/6-311+G(3df,2p) level of theory. The results obtained reveal similarities between these structures: a pentatomic, nonaromatic ring is present in the oxidized forms, while an unbranched aliphatic chain (as found in saturated fatty acids) is present in both the oxidized and the reduced forms. Analysis of the spin density and the highest occupied molecular orbital energy revealed that the SH groups exhibited the greatest electron-donating activities. The values obtained for the proton affinity, bond dissociation enthalpy and adiabatic ionization potential indicate that the preferred antioxidant mechanisms for α-lipoic acid and its metabolites are sequential proton loss electron transfer in polar media and hydrogen atom transfer in vacuum

Rodzina w zdrowiu i w chorobie. Uwarunkowania środowiskowe zdrowia

Praca recenzowana / peer-reviewed pape