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41.
The molecular and crystal structures of the lidocaine analogs 2-(pyrazol-1-yl)-2′-methylacetanilide (1), 2-(3,5-dimethyl-4-iodo-pyrazol-1-yl)-2′-methylacetanilide (2), 2-(3,5-dimethyl-4-iodo-pyrazol-1-yl)-3′-methylacetanilide (3), and 2-(pyrazol-1-yl)-4′-methylacetanilide (4), are reported, with a summary of their pharmacological activities. In this series, the moiety comprising the heterocyclic
ring and the amide alkyl linker displays a common conformation. Molecules of 1–4 form identical hydrogen bonded motifs in their crystals, namely linear chains via intermolecular N–H···O=C hydrogen bonding.
Moderate anesthetic and anti-arrhythmic potencies recorded for 1–4 relative to lidocaine are countered by their significantly lower toxicities. 相似文献
42.
Monatshefte für Mathematik - Labyrinth fractals are self-similar dendrites in the unit square that are defined with the help of a labyrinth set or a labyrinth pattern. In the case when the... 相似文献
43.
Mihaela Alexandru Maria Cazacu Mariana Cristea Alexandra Nistor Cristian Grigoras Bogdan C. Simionescu 《Journal of polymer science. Part A, Polymer chemistry》2011,49(7):1708-1718
Poly(siloxane‐urethane) crosslinked structures were prepared from isophorone diisocyanate, α,ω‐bis(hydroxybutyl)oligodimethylsiloxane and a new hybrid diol containing hydrolysable Si? OC2H5 groups besides OH groups. The latest was synthesized by the acid‐catalyzed reaction between 1,3‐bis(3‐glycidoxypropyl)tetramethyldisiloxane and 3‐aminopropyltriethoxysilane. The formations of the urethane groups along the polymer backbone as well as the formation of the silica domains were first confirmed by the presence of the specific bands in Fourier transform infrared spectra. The resulted materials were characterized using differential scanning calorimetry, thermogravimetric analysis and scanning electron microscopy. The results of the dynamic mechanical analysis (DMA) performed at various frequencies revealed shape memory capabilities for some of the obtained structures. The silica formed because of the hydrolysis‐condensation reactions proved to have reinforcing effect upon siloxane‐urethane structure also evidenced by DMA and increasing water vapor sorption capacity as was measured by dynamic vapor sorption. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
44.
Luiza Găină Emese Gal Larisa Mătărângă-Popa Dan Porumb Alina Nicolescu Castelia Cristea Luminita Silaghi-Dumitrescu 《Tetrahedron》2012,68(11):2465-2470
Comparison studies on the acetalization of 10-methyl-10H-phenothiazine-carbaldehyde with 1,3-propanediol, or 2-substituted-1,3-propanediols, under conventional versus microwave assisted conditions and standard organic solvents versus water, were performed as an attempt toward more environmentally benign synthetic methods. New 3-(1,3-dioxan-2-yl)-10-methyl-10H-phenothiazine derivatives were obtained in high yields by azeotropic distillation of water and in moderate yields by microwave assisted synthesis in different solvents, including water under superheated conditions. The solvent influence upon stabilizing the key intermediates involved in the acetalization mechanism was assumed based on DFT calculations, which indicated a favorable enthalpy profile in water solvent. Structural investigations of the new compounds based on spectroscopic methods (NMR, FT-IR, UV–vis, and MS), were completed with molecular mechanics and semi-empirical DFT calculations, which supported an anancomeric chair conformation of the 1,3-dioxane ring with the phenothiazine substituent in the equatorial position and possible free rotation about the single bond linking the two heterocyclic units. The new compounds display daylight fluorescence characterized by remarkably large Stokes shifts determined by LE spectroscopy. 相似文献
45.
We study certain order statistics with respect to (probability) mass distributions of multinomial type on the unit interval. The asymptotic behaviour of the average minimum and, respectively, maximum value among \(n\) words chosen independently at random with respect to the corresponding probability measure is analysed. This is done by a combination of a method based on the Mellin transform and the depoissonisation technique. 相似文献
46.
Stable isotopes determination in some Romanian wines 总被引:1,自引:0,他引:1
Magdas DA Cuna S Cristea G Ionete RE Costinel D 《Isotopes in environmental and health studies》2012,48(2):345-353
This paper presents a study concerning the isotopic fingerprint ((18)O and (13)C) of some wines prepared from relevant Romanian grape varieties (e.g. Feteasca Alba (FA), Feteasca Regala (FR) and Cabernet Sauvignon (CS)) obtained in different vintage years (2002, 2003, 2004, 2007 and 2008). These wines were obtained from different vineyards having a significant role in the wine market: Cotesti, Tohani, Stefanesti, Aiud, Cotnari, Bucium, Murfatlar, Bujoru, Dragasani and Valea Calugareasca. Several observations related to the dependence of isotope ratios on geographical origin and climatic conditions were drawn. The authentic wines obtained from the FA grape variety from six different vineyards showed δ(18)O values in the range of+3.28 (Cotesti region - 45?°38'N/27?°04'E) to-2.60 ‰ (Aiud region - 46?°19'N/23?°45'E). The δ(13)C values were very similar for all the samples with an average of about-26 ‰. The difference between the δ(18)O values was due to the different climatic zones, which have an influence on the δ(18)O values of wine water. For the wine variety CS obtained from the Dealu Mare-Tohani vineyard, production years 2003 and 2004, a greater difference in the δ(18)O values of wine water ranging from 1.89 (in 2004) to 5.35 ‰ (in 2003) was noted. This difference is explained by the different mean annual temperatures in 2003 and 2004. 相似文献
47.
Dynamic mechanical experiments performed on a semicrystalline sample of poly(ethylene terephthalate) evidenced the relaxation processes (α and β) that occur in the polymer. Multifrequency experiments were used both in order to calculate the apparent activation energy of relaxation and to point out how the dynamic conditions alter not only the main relaxations, but the overlapping melting/recrystallization events that succeed after the glass transition. Heating rate seems to affect these phenomena in a way similar to frequency. Also, a consecutive heating step was carried out to support the statements. 相似文献
48.
Aliona Ghendov-Mosanu Elena Cristea Antoanela Patras Rodica Sturza Marius Niculaua 《Molecules (Basel, Switzerland)》2020,25(23)
The present study analyzes the complex of bioactive compounds from rose hips pulp powder (RHP) obtained after separating the seeds from Rosa canina L. in order to obtain the oil. The extract prepared from RHP was characterized in terms of the total content of polyphenols, flavonoids, cinnamic acids, flavonols, carotenoids, but also the content of individual polyphenols and carotenoids, antioxidant activity, and CIELab color parameters. The effects of some salts, potentially present in foods, and pH variations were examined to predict possible interactions that could occur when adding rosehip pulp as a food component. The results turned out to be a high content of polyphenols, carotenoids and antioxidant activity. The main phenolic components are procyanidin B1, chlorogenic acid, epicatechin, procyanidin B2, gallic acid, salicylic acid, and catechin. The carotenoid complex includes all-trans-β-carotene, all-trans-lycopene, zeaxanthin, α-cryptoxanthin, β-cryptoxanthin, rubixanthin, cis-β-carotene, cis-γ-carotene and cis-lycopene. The addition of CaCl2 and NaCl to the RHP extract reduced the antioxidant activity and the strong acidic environment (pH to 2.5) decreased the antioxidant activity by 29%. The addition of rose hip powder to gingerbread has improved its general characteristics, and increased its antioxidant activity and microbiological stability, the effects of 4% RHP being the most important. 相似文献
49.
Mihai Cristea 《Complex Analysis and Operator Theory》2011,5(3):863-880
The paper continues the work of Royster (Duke Math J 19:447–457, 1952), Mocanu [Mathematica (Cluj) 22(1):77–83, 1980; Mathematica
(Cluj) 29:49–55, 1987], Cristea [Mathematica (Cluj) 36(2):137–144, 1994; Complex Var 42:333–345, 2000; Mathematica (Cluj)
43(1):23–34, 2001; Mathematica (Cluj), 2010, to appear; Teoria Topologica a Functiilor Analitice, Editura Universitatii Bucuresti,
Romania, 1999] of extending univalence criteria for complex mappings to C
1 mappings. We improve now the method of Loewner chains which is usually used in complex univalence theory for proving univalence
criteria or for proving quasiconformal extensions of holomorphic mappings f : B → C
n
to C
n
. The results are surprisingly strong. We show that the usual results from the theory, like Becker’s univalence criteria remain
true for C
1 mappings and since we use a stronger form of Loewner’s theory, we obtain results which are stronger even for holomorphic
mappings f : B → C
n
. In our main result (Theorem 4.1) we end the researches dedicated to quasiconformal extensions of K-quasiregular and holomorphic mappings f : B → C
n
to C
n
. We show that a C
1 quasiconformal map f : B → C
n
can be extended to a quasiconformal map F : C
n
→ C
n
, without any metric condition imposed to the map f. 相似文献
50.
Elena Cristea Aliona Ghendov-Mosanu Antoanela Patras Carmen Socaciu Adela Pintea Cristina Tudor Rodica Sturza 《Molecules (Basel, Switzerland)》2021,26(13)
Recent trends in the food industry combined with novel methods in agriculture could transform rowan into a valuable raw material with potential technological applications. Thus, the aim of this research was to investigate the content of bioactive compounds in its fruits and to assess the color and antioxidant stability of the extracts prepared from such fruits during various thermal treatments and at different pH and ionic strength values. Various spectrophotometric methods, HPLC, and capillary electrophoresis were used to quantify the concentrations of bioactive compounds—polyphenols, carotenoids, organic acids, and to assess antioxidant activity and color. The results show that rowan berries contain circa 1.34–1.47 g/100 g of polyphenols among which include catechin, epicatechin, ferulic acid methyl ester, procyanidin B1, etc.; ca 21.65 mg/100 g of carotenoids including zeaxanthin, β-cryptoxanthin, all-trans-β-carotene, and various organic acids such as malic, citric, and succinic, which result in a high antioxidant activity of 5.8 mmol TE/100 g. Results also showed that antioxidant activity exhibited high stability when the extract was subjected to various thermal treatments, pHs, and ionic strengths, while color was mainly impacted negatively when a temperature of 100 °C was employed. This data confirms the technological potential of this traditional, yet often overlooked species. 相似文献