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81.
We describe all subdirectly irreducible medial quandles. We show that they fall within one of four disjoint classes. In particular, in the finite case they are either connected (and therefore Alexander quandles) or reductive. Moreover, we provide a representation of all non-connected subdirectly irreducible medial quandles. 相似文献
82.
Brian Kaczmarczyk Justyna Kalisz Ewa Kijeńska-Gawrońska Krzysztof Maksymiuk Agata Michalska 《Electroanalysis》2023,35(6):e202200496
Nanofibers mats, prepared from poly(vinyl chloride) (PVC) containing dispersed dye Nile red (NR) were applied in a proof of concept study as optical sensors for Volatile Organic Compounds (VOCs) dispersed in an aqueous phase. Benefiting from the solubility of the dye, and in some cases, also of the polymer in model solvents belonging to the group of VOCs, an increase of emission was observed for increasing solvent concentration in the sample. The optical signal formation was observed regardless if only the dye or both dye and PVC were soluble in the tested solvent. In both cases, high sensitivity emission increases for increasing VOCs present in the aqueous phase were observed within the range of concentration of model analytes: from 200 ppm of m-xylene or from 300 ppm of styrene, to up to ca 1500 ppm. The obtained higher detection limit was lower compared to films of PVC containing the dye due to the lower availability of the material to be dissolved by analyte – solvent. The large surface area of nanofibers was useful in the detection, leading to higher signal changes compared to films. 相似文献
83.
We present a first-principles study of hydrogen bonding effect on current-voltage characteristics of molecular junctions. Three model charge-transfer molecules, 2'-amino-4,4'-di(ethynylphenyl)-1-benzenethiolate (DEPBT-D), 4,4'-di(ethynylphenyl)-2'-nitro-1-benzenethiolate (DEPBT-A), and 2'-amino-4,4'-di(ethynylphenyl)-5'-nitro-1-benzenethiolate (DEPBT-DA), have been examined and compared with the corresponding hydrogen bonded complexes formed with different water molecules. Large differences in current-voltage characteristics are observed for DEPBT-D and DEPBT-A molecules with or without hydrogen bonded waters, while relatively small differences are found for DEPBT-DA. It is predicted that the presence of water clusters can drastically reduce the conductivities of the charge-transfer molecules. The underlying microscopic mechanism has been discussed. 相似文献
84.
Alina Sionkowska Sławomir Skrzyński Krzysztof Śmiechowski Agata Kołodziejczak 《先进技术聚合物》2017,28(1):4-9
This review reports recent advances in the versatile application of collagen. Collagen materials have attracted great attention because they exhibit properties required in cosmetic preparations, in the biomedical field, and in the tanning industry leading to leather production. Herein, the structure and application of collagen are discussed in general, and detailed examples are also drawn from scientific literature and practical work. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
85.
Agata Smoktunowicz 《Israel Journal of Mathematics》2017,219(2):555-608
A well-known theorem by S. A. Amitsur shows that the Jacobson radical of the polynomial ring R[x] equals I[x] for some nil ideal I of R. In this paper, however, we show that this is not the case for differential polynomial rings, by proving that there is a ring R which is not nil and a derivation D on R such that the differential polynomial ring R[x;D] is Jacobson radical. We also show that, on the other hand, the Amitsur theorem holds for a differential polynomial ring R[x;D], provided that D is a locally nilpotent derivation and R is an algebra over a field of characteristic p > 0. The main idea of the proof introduces a new way of embedding differential polynomial rings into bigger rings, which we name platinum rings, plus a key part of the proof involves the solution of matrix theory-based problems. 相似文献
86.
PMB ethers of alcohols are obtained in good yields and under mild conditions using the 4-methoxybenzyl N-allyl thiocarbamate and N-bromosuccinimide (NBS)/TfOH as the catalyst. The present method is very fast, simple, and efficient. 相似文献
87.
Muammer Kula 《Acta Mathematica Hungarica》2011,133(1-2):14-32
In previous papers, various notions of (strongly) closed subobject, (strongly) open subobject, connected, compact and T i , i=0,1,2 objects in a topological category were introduced and compared. The main objective of this paper is to characterize each of these classes of objects in the category of Cauchy spaces as well as to examine how these generalizations are related. 相似文献
88.
Agata Górniak Alina Wojakowska Bożena Karolewicz Janusz Pluta 《Journal of Thermal Analysis and Calorimetry》2011,104(3):1195-1200
Enhancement of the dissolution rate of poorly soluble compounds through the formation of drug–drug eutectics was investigated
using fenofibrate and acetylsalicylic acid. Solid–liquid equilibria in the system under study were investigated by differential
scanning calorimetry (DSC). The phase diagram for the whole range of compositions was constructed. In addition, existence
of a metastable polymorph of fenofibrate has been confirmed. The investigation has revealed that acetylsalicylic acid and
fenofibrate form a simple eutectic mixture containing 0.958 mol fraction of fenofibrate at the eutectic point. Dissolution
rate improvement of fenofibrate correlated with the phase diagram. The amount of fenofibrate released from the solid dispersions
that contained fenofibrate as the eutectic mixture with acetylsalicylic acid was at least threefold higher compared to untreated
fenofibrate. 相似文献
89.
Katarzyna Kaa Wojciech Pajk Katarzyna Sukowska-Ziaja Agata Krakowska Jan Lazur Maciej Fidurski Krystian Marzec Piotr Ziba Agata Fijakowska Agnieszka Szewczyk Boena Muszyska 《Molecules (Basel, Switzerland)》2022,27(24)
Hypsizygus marmoreus is an edible medicinal mushroom species with a high dietary value. In this study, the fruiting bodies of commercial and self-cultivated crops and mycelium from in vitro H. marmoreus cultures (both white and brown varieties) were evaluated. This study aimed to analyze the presence of indole compounds and other biologically active substances and determine the effect that the addition of zinc and magnesium ions to the culture medium has on the content of the tested compounds in mycelial cultures. The content of indole compounds and other organic compounds was determined using high-performance liquid chromatography, the content of bioelements was determined using flame atomic absorption spectrometry, the glucan content was determined spectrophotometrically, and the antioxidant activity of extracts was estimated using DPPH, FRAP, and ABTS methods. The results showed that H. marmoreus mycelium from in vitro cultures is a good source of indole compounds, bioelements, glucans, and lovastatin. Mycelia from in vitro cultures showed the most diverse composition of indole compounds (L-tryptophan, 5-hydroxy-L-tryptophan, tryptamine, 5-methyltryptamine, and melatonin). Additionally, in vitro cultures of H. marmoreus enriched with Zn and Mg salts increased the contents of Na, Ca, Zn, 5-methyltryptamine, melatonin, protocatechuic acid, sterols, and total glucans. Only in the case of the white variety of mycelial enriched cultures, ergothioneine and Mg levels also increased. To summarize, the content of the active compounds differed depending on the H. marmoreus variety and the tested material. 相似文献
90.
Renata ?yszczek Zofia Rz?czyńskaAlina Kula Agnieszka G?adysz-P?aska 《Journal of Analytical and Applied Pyrolysis》2011,92(2):347-354
The lanthanide 2,6-naphthalenedicarboxylates series of the formulas Ln2(ndc)3·nH2O, where Ln = lanthanides from La(III) to Lu(III); ndc - C10H6(COO)22−; n = 4, 4.5 or 5 have been prepared by the precipitation method. All obtained products were examined and characterized by elemental analysis, FTIR spectroscopy, simultaneous thermal analyses TG-DSC and TG-FTIR, X-Ray diffraction patterns as well as luminescence measurements. The crystalline compounds form three isostructural groups: Ce-Sm; La and Eu-Dy; Ho-Lu. In all complexes, the ndc2− ligand appears in the deprotonated form. Heating of the complexes resulted in the multi-steps decomposition process. The dehydration process leads to the formation of stable crystalline Ln2ndc3 compounds which further decompose to the corresponding lanthanide oxides (air atmosphere). In argon atmosphere they decompose with releasing of water, carbon oxides and naphthalene molecules. The luminescence properties of Eu(III), Nd(III), Tb(III) and Er(III) complexes were investigated. The complexes of Eu(III) and Tb(III) emitted red and green light when excited by ultraviolet light whereas Nd(III) and Er(III) display emissions in the NIR region. 相似文献