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排序方式: 共有147条查询结果,搜索用时 15 毫秒
1.
5,6-O-Cyclohexylidene-1-amino-3-azahexane (L) is synthesized from 1-chloro-2,3-O-cyclohexylidenepropane, which is prepared by the reaction between epichlorohydrin and cyclohexanone. In this reaction, BF3 · OEt2 is used as a catalyst. Complexes of Co(II), Ni(II) and Cu(II) acetates with this ligand are prepared. The structures of the ligand and its complexes are proposed based on elemental analysis, IR and UV-VIS spectroscopy, magnetic susceptibility, conductometry, and 1H and 13C NMR spectroscopy. 相似文献
2.
Turan Ozturk Andrey S. Klymchenko Sule Oncul Sule Taskiran F. Betul Kaynak Alexander P. Demchenko 《Tetrahedron》2007,63(41):10290-10299
Nine new 3-hydroxyflavone derivatives as fluorescent molecular sensors having two well-separated emission bands were synthesized. These sensors can occupy well-determined locations and orientations in macromolecular ensembles, such as micelles due to their finely-tuned designs. These polarity-sensitive dyes can incorporate into the anhydrous hydrophobic core of aqueous micelles. 相似文献
3.
Post-implantation annealing of N-implanted 304 stainless steel at 400 °C has been investigated by conversion electron Mössbauer spectroscopy, X-ray diffraction and Auger electron spectroscopy. After a 1 h anneal, the near complete dissolution of the as-implanted Fe2N-like nitride phase results in a 9 at.% N fcc solid-solution phase. After the final anneal (64 h), N has diffused to a depth of about 2 m and remains in solid solution with an average content of 4 at.%. An average N diffusion coefficient at 400 °C is estimated to be 10-12-10-14 cm2/s, depending on anneal time, too small to explain the deep penetration observed in high-flux, high-dose N-implanted stainless steel. The present results provide additional evidence for beam controlled N migration where Cr plays an important role. 相似文献
4.
Refiye Beyza Ozturk Gokhan Zengin Kouadio Ibrahime Sinan Domenico Montesano Dimitrina Zheleva-Dimitrova Reneta Gevrenova Abdullahi Ibrahim Uba Uur aklcolu Alevcan Kaplan Sharmeen Jugreet Stefano DallAcqua Mohamad Fawzi Mahomoodally 《Molecules (Basel, Switzerland)》2022,27(15)
The bioactive content, antioxidant properties, and enzyme inhibition properties of extracts of Alcea fasciculiflora from Turkey prepared with different solvents (water, methanol, ethyl acetate) and extraction methods (maceration, soxhlet, homogenizer assisted extraction, and ultrasound assisted extraction) were examined in this study. UHPLC-HRMS analysis detected or annotated a total of 50 compounds in A. fasciculiflora extracts, including 18 hydroxybenzoic and hydroxycinnamic acids, 7 Hexaric acids, 7 Coumarins, 15 Flavonoids, and 3 hydroxycinnamic acid amides. The extracts had phenolic and flavonoid levels ranging from 14.25 to 24.87 mg GAE/g and 1.68 to 25.26 mg RE/g, respectively, in the analysis. Both DPPH and ABTS tests revealed radical scavenging capabilities (between 2.63 and 35.33 mg TE/g and between 13.46 and 76.27 mg TE/g, respectively). The extracts had reducing properties (CUPRAC: 40.38–78 TE/g and FRAP: 17.51–42.58 TE/g). The extracts showed metal chelating activity (18.28–46.71 mg EDTAE/g) as well as total antioxidant capacity (phosphomolybdenum test) (0.90–2.12 mmol TE/g). DPPH, ABTS, FRAP, and metal chelating tests indicated the water extracts to be the best antioxidants, while the ethyl acetate extracts had the highest overall antioxidant capacity regardless of the extraction technique. Furthermore, anti-acetylcholinesterase activity was identified in all extracts (0.17–2.80 mg GALAE/g). The water extracts and the ultrasound-assisted ethyl acetate extract were inert against butyrylcholinesterase, but the other extracts showed anti-butyrylcholinesterase activity (1.17–5.80 mg GALAE/g). Tyrosine inhibitory action was identified in all extracts (1.79–58.93 mg KAE/g), with the most effective methanolic extracts. Only the ethyl acetate and methanolic extracts produced by maceration and homogenizer aided extraction showed glucosidase inhibition (0.11–1.11 mmol ACAE/g). These findings showed the overall bioactivity of the different extracts of A. fasciculiflora and provided an overview of the combination of solvent type and extraction method that could yield bioactive profile and pharmacological properties of interest and hence, could be a useful reference for future studies on this species. 相似文献
5.
Acta Mathematicae Applicatae Sinica, English Series - In present note, we apply the Leibniz formula with the nabla operator in discrete fractional calculus (DFC) due to obtain the discrete... 相似文献
6.
Acta Mathematicae Applicatae Sinica, English Series - In present note, we apply the Leibniz formula with the nabla operator in discrete fractional calculus (DFC) due to obtain the discrete... 相似文献
7.
Lipomatous tumors of the uterus are unusual, benign neoplasms seen in postmenopausal women. Although many of the mixed-type cases such as lipoleiomyoma and fibrolipoma have been reported, pure uterine lipomas are extremely rare. In the literature, a few cases with pure uterine lipoma have been reported. We first present the advanced magnetic resonance findings of pure uterine lipoma, followed by those of ultrasonography (US) and computed tomography (CT). We markedly detected lipid peaks on the magnetic resonance spectroscopy (MRS) and the apparent diffusion coefficient value to be 0.00 due to chemical-shift effects with diffusion-weighted imaging (DWI). Although pelvic lipomatous tumors can be diagnosed with US and CT, in some cases, further workup may be required to localize the lesion. MRI may yield more valuable data for differential diagnosis. MRS and DWI findings provide additional clues on the nature of the lesion. 相似文献
8.
E. Ozturk 《The European Physical Journal B - Condensed Matter and Complex Systems》2010,75(2):197-203
The laser field dependence of the linear and nonlinear intersubband optical absorption in a graded quantum well (GQW) under an applied electric field is investigated in the effective mass approximation. In our calculations, the position and the magnitude of the linear and total absorption coefficients depend on the laser parameter and electric field strength. The resonant peak of total absorption coefficient can be bleached at sufficiently high incident optical intensities. Such a dependence of the exciting optical intensity on the external field strengths in GQWs can be very useful for several potential device applications. 相似文献
9.
The intersubband absorption in square and graded quantum wells under a laser field is calculated within the framework of the effective mass approximation. We conclude that, for quantum wells with different shapes, the laser field amplitude induces an important effect on the electronic and optical properties of the semiconductor structure. This gives a new degree of freedom in various device applications based on the intersubband transition of electrons. 相似文献
10.