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161.
Chain geometry associated with an affine group and with a linear group is studied. In particular, closely related to the respective chain geometries affine partial linear spaces and generalizations of sliced spaces are defined. The automorphisms of thus obtained structures are determined. 相似文献
162.
Application of microextraction by packed sorbent to isolation of psychotropic drugs from human serum
Wietecha-Posłuszny R Garbacik A Woźniakiewicz M Moos A Wieczorek M Kościelniak P 《Analytical and bioanalytical chemistry》2012,402(7):2249-2257
A method of microextraction by packed sorbent (MEPS) followed by liquid chromatography with diode array detection has been
developed and optimized for the extraction of six tricyclic antidepressants (amitriptyline, nortriptyline, imipramine, desipramine,
doxepin, nordoxepin) from human serum. The optimal parameters of MEPS extraction (type of sorbent, volume of sample, composition,
and volume of washing and elution solutions) for these drugs in spiked samples were defined. The developed MEPS procedure
was validated and then successfully applied to the analysis of serum reference material. The limit of detection (0.02–0.05 μg/mL),
intraday (2.7–8.8%) and interday (4.4–11.6%) precision (RSD), and the accuracy of the assay (94.5–108.8%) at three concentration
levels—0.2, 0.5, and 0.8 μg/mL—were estimated. The accuracy of the method was evaluated by the analysis of certified reference
material. Moreover, the validated procedure was compared with the solid-phase extraction technique. Finally, microextraction
by packed sorbent was assessed as a suitable tool in forensic and clinical methods for serum sample preparations. 相似文献
163.
Jolanta Kowalska Agata Marzec Ewa Domian Sabina Galus Agnieszka Ciurzyska Rita Brzeziska Hanna Kowalska 《Molecules (Basel, Switzerland)》2021,26(16)
The polyphenol content of tea depends on the growing region, harvest date, the production process used, and the brewing parameters. In this study, research was undertaken that included an analysis of the influence of the brewing process parameters on the content of total polyphenols (Folin-Ciocalteu), epigallocatechin gallate (HPLC), and antioxidant activity (against DPPH radicals) of fresh tea shrub leaves grown from Taiwan and of teas obtained from them (oolong, green in bags, and green loose from the spring and autumn harvest). The antioxidant potential was determined in the methanol and aqueous extracts, as well as in infusions that were obtained by using water at 65 or 100 °C and infusing the tea for 5 or 10 min. The highest content of total polyphenols and epigallocatechin gallate was found in green tea extracts from the spring harvest. However, in the case of infusions, the highest content of these compounds was found in green tea in bags. Steaming at 100 °C for 10 min, turned out to be the most favourable condition for the extraction. Oolong tea, brewed at 100 °C for 5 min was characterised by the highest antioxidant activity against stable DPPH radicals. 相似文献
164.
Marcin Palusiak Arno Pfitzner Manfred Zabel Sawomir J. Grabowski Jan Epsztajn Justyna A. Kowalska 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(4):o239-o241
In methyl [5‐methoxy‐4‐(4‐methoxyphenyl)isochroman‐3‐yl]acetate, C20H22O5, (I), and methyl [4‐(2,5‐dimethoxyphenyl)‐8‐methoxyisochroman‐3‐yl]acetate, C21H24O6, (II), the heterocyclic rings adopt half‐chair conformations. The substituents at the 3‐ and 4‐positions are in a trans configuration in both (I) and (II), being in an axial conformation in (I) and in an equatorial conformation in (II). The crystal structure of (I) is stabilized by weak C—H⋯O hydrogen bonding, leading to the formation of an infinite three‐dimensional network. Compound (II) crystallizes in a chiral space group. This feature, which was also found in previously investigated isochroman derivatives, is related to the arrangement of substituents attached to the isochroman moiety. 相似文献
165.
Jolanta Kowalska Jzef Tyburski Kinga Matysiak Magdalena Jakubowska Joanna ukaszyk Joanna Krzymiska 《Molecules (Basel, Switzerland)》2021,26(17)
Cinnamon is widely used as a food spice, but due to its antibacterial and pharmacological properties, it can also be used in processing, medicine and agriculture. The word “Cinnamon” can refer to the plant, processed material, or an extract. It is sometimes used as a substance, and sometimes used as a mixture or as compounds or a group. This article reviews research into the effectiveness of various forms of cinnamon for the control of plant diseases and pests in crops and during storage of fruit and vegetables. Cinnamon acts on pests mainly as a repellent, although in higher doses it has a biocidal effect and prevents egg-laying. Cinnamon and its compounds effectively hinder bacterial and fungal growth, and the phytotoxic effects of cinnamon make it a possible herbicide. This article presents the wide practical use of cinnamon for various purposes, mainly in agriculture. Cinnamon is a candidate for approval as a basic substance with protective potential. In particular, it can be used in organic farming as a promising alternative to chemical pesticides for use in plant protection, especially in preventive treatments. The use of natural products is in line with the restriction of the use of chemical pesticides and the principles of the EU’s Green Deal. 相似文献
166.
167.
Joanna K. Kowalska Justin T. Henthorn Casey VanStappen Christian Trncik Oliver Einsle David Keavney Serena DeBeer 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(28):9473-9477
Nitrogenase enzymes catalyze the reduction of atmospheric dinitrogen to ammonia utilizing a Mo‐7Fe‐9S‐C active site, the so‐called FeMoco cluster. FeMoco and an analogous small‐molecule (Et4N)[(Tp)MoFe3S4Cl3] cubane have both been proposed to contain unusual spin‐coupled MoIII sites with an S(Mo)=1/2 non‐Hund configuration at the Mo atom. Herein, we present Fe and Mo L3‐edge X‐ray magnetic circular dichroism (XMCD) spectroscopy of the (Et4N)[(Tp)MoFe3S4Cl3] cubane and Fe L2,3‐edge XMCD spectroscopy of the MoFe protein (containing both FeMoco and the 8Fe‐7S P‐cluster active sites). As the P‐clusters of MoFe protein have an S=0 total spin, these are effectively XMCD‐silent at low temperature and high magnetic field, allowing for FeMoco to be selectively probed by Fe L2,3‐edge XMCD within the intact MoFe protein. Further, Mo L3‐edge XMCD spectroscopy of the cubane model has provided experimental support for a local S(Mo)=1/2 configuration, demonstrating the power and selectivity of XMCD. 相似文献
168.
Nataliya Stankevich Erik Mosekilde Aneta Koseska 《The European physical journal. Special topics》2018,227(7-9):747-756
Complex biochemical networks are commonly characterised by the coexistence of multiple stable attractors. This endows living systems with plasticity in responses under changing external conditions, thereby enhancing their probability for survival. However, the type of such attractors as well as their positioning can hinder the likelihood to randomly visit these areas in phase space, thereby effectively decreasing the level of multistability in the system. Using a model based on the Hodgkin–Huxley formalism with bistability between a silent state, which is a rare attractor, and oscillatory bursting attractor, we demonstrate that the noise-induced switching between these two stable attractors depends on the structure of the phase space and the disposition of the coexisting attractors to each other. 相似文献
169.
M. Kowalska S. Naimi J. Agramunt A. Algora G. Audi D. Beck B. Blank K. Blaum Ch. B?hm M. Breitenfeldt E. Estevez L. M. Fraile S. George F. Herfurth A. Herlert A. Kellerbauer D. Lunney E. Minaya-Ramirez D. Neidherr B. Olaizola K. Riisager M. Rosenbusch B. Rubio S. Schwarz L. Schweikhard U. Warring 《The European Physical Journal A - Hadrons and Nuclei》2009,42(3):351-359
With the Penning trap mass spectrometer ISOLTRAP, located at ISOLDE/CERN, preparatory work has been performed towards mass and decay studies on neutron-rich Hg and Tl isotopes beyond N = 126 . The properties of these isotopes are not well known because of large isobaric contamination coming mainly from surface-ionised Fr. Within the studies, production tests using several target-ion source combinations were performed. It was furthermore demonstrated around mass number A = 209 that the resolving power required to purify Fr is achievable with ISOLTRAP. In addition, masses of several isobaric contaminants, 211-213Fr and 211Ra , were determined with a three-fold improved precision. The results influence masses of more than 20 other nuclides in the 208Pb region. 相似文献
170.
ABSTRACTThe method and basis set dependence of zero-point vibrational corrections (ZPVCs) to nuclear magnetic resonance shielding constants and anisotropies has been investigated using water as a test system. A systematic comparison has been made using the Hartree–Fock, second-order Møller–Plesset perturbation theory (MP2), coupled cluster singles and doubles (CCSD), coupled cluster singles and doubles with perturbative triples corrections (CCSD(T)) and Kohn–Sham density functional theory with the B3LYP exchange-correlation functional methods in combination with the second-order vibrational perturbation theory (VPT2) approach for the vibrational corrections. As basis sets, the correlation consistent basis sets cc-pVXZ, aug-cc-pVXZ, cc-pCVXZ and aug-cc-pCVXZ with X = D, T, Q, 5, 6 and the polarisation consistent basis sets aug-pc-n and aug-pcS-n with n = 1, 2, 3, 4 were employed. Our results show that basis set convergence of the vibrational corrections is not monotonic and that very large basis sets are needed before a reasonable extrapolation to the basis set limit can be performed. Furthermore, our results suggest that coupled cluster methods and a decent basis set are required before the error of the electronic structure approach is lower than the inherent error of the VPT2 approximation. 相似文献