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151.
D.M. Wang Y.H. Ren X. Liu J.K. Furdyna M. Grimsditch R. Merlin 《Superlattices and Microstructures》2007,41(5-6):372
Coherent oscillations of the magnetization were observed in magneto-optical Kerr measurements in thin films of the ferromagnetic semiconductor GaMnAs. For magnetic fields oriented in the film plane, two precession modes were observed. Their frequencies increase with the field when it is along the [100] axis, whereas they behave non-monotonically when the field is oriented along the in-plane hard axis [110]. Spectra are also presented for fields applied normal to the film plane. From the measured field-dependence of the magnon frequency, the spin stiffness and magnetic anisotropy constants were obtained. 相似文献
152.
Naphthenic acids (general formula C(n)H(2n+Z)O(2)) are water-soluble, toxic compounds found in petroleum and bitumen. Some of the current methods for detecting these acids in waters depend on measuring the presence of the carboxylic acid functional group, and therefore many of these methods also detect naturally occurring carboxylic acids that are not naphthenic acids. We report a procedure that includes liquid-liquid extraction, cleanup, and derivatization to form t-butyldimethylsilyl esters prior to gas chromatography-mass spectrometry (GC-MS) analysis. Using low- and high-resolution MS to detect the ion C(15)H(27)O(2)Si(+) (nominal m/z=267) is an excellent indicator of the presence of naphthenic acids at concentrations > or =10microgL(-1). 相似文献
153.
Stephan Barcikowski Anne Hahn Merlin Guggenheim Kerstin Reimers Andreas Ostendorf 《Journal of nanoparticle research》2010,12(5):1733-1742
Nanoactuators made from nanoparticulate NiTi shape memory alloy show potential in the mechanical stimulation of bone tissue
formation from stem cells. We demonstrate the fabrication of Ni, Ti, and NiTi shape memory alloy nanoparticles and their biocompatibility
to human adipose-derived stem cells. The stoichiometry and phase transformation property of the bulk alloy is preserved during
attrition by femtosecond laser ablation in liquid, giving access to colloidal nanoactuators. No adverse effect on cell growth
and attachment is observed in proliferation assay and environmental electron scanning microscopy, making this material attractive
for mechanical stimulation of stem cells. 相似文献
154.
Alexander Okorn Arumugam Jayaraman Lukas Englert Merle Arrowsmith Theresa Swoboda Jeanette Weigelt Carina Brunecker Merlin Hess Anna Lamprecht Carsten Lenczyk Maximilian Rang Holger Braunschweig 《Chemical science》2022,13(25):7566
The classical route to the PMe3-stabilised polycyclic aromatic hydrocarbon (PAH)-substituted diborenes B2Ar2(PMe3)2 (Ar = 9-phenanthryl 7-Phen; Ar = 1-pyrenyl 7-Pyr) via the corresponding 1,2-diaryl-1,2-dimethoxydiborane(4) precursors, B2Ar2(OMe)2, is marred by the systematic decomposition of the latter to BAr(OMe)2 during reaction workup. Calculations suggest this results from the absence of a second ortho-substituent on the boron-bound aryl rings, which enables their free rotation and exposes the B–B bond to nucleophilic attack. 7-Phen and 7-Pyr are obtained by the reduction of the corresponding 1,2-diaryl-1,2-dichlorodiborane precursors, B2Ar2Cl2(PMe3)2, obtained from the SMe2 adducts, which are synthesised by direct NMe2–Cl exchange at B2Ar2(NMe2)2 with (Me2S)BCl3. The low-lying π* molecular orbitals (MOs) located on the PAH substituents of 7-Phen and 7-Pyr intercalate between the B–B-based π and π* MOs, leading to a relatively small HOMO–LUMO gap of 3.20 and 2.72 eV, respectively. Under vacuum or at high temperature 7-Phen and 7-Pyr undergo intramolecular hydroarylation of the B B bond to yield 1,2-dihydronaphtho[1,8-cd][1,2]diborole derivatives. Hydrogenation of 7-Phen, 7-Pyr and their 9-anthryl and mesityl analogues III and II, respectively, results in all cases in splitting of the B–B bond and isolation of the monoboranes (Me3P)BArH2. NMR-spectroscopic monitoring of the reactions, solid-state structures of isolated reaction intermediates and computational mechanistic analyses show that the hydrogenation of the three PAH-substituted diborenes proceeds via a different pathway to that of the dimesityldiborene. Rather than occurring exclusively at the B–B bond, hydrogenation of 7-Ar and III proceeds via a hydroarylated intermediate, which undergoes one B–B bond-centered H2 addition, followed by hydrogenation of the endocyclic B–C bond resulting from hydroarylation, making the latter effectively reversible.In contrast to classical B–B bond-centred diborene hydrogenation, polycyclic aromatic hydrocarbon-substituted diborenes first undergo thermal intramolecular hydroarylation, followed by hydrogenation of the remaining B–B and endocyclic B–C bonds. 相似文献
155.
Flvia A. R. dos Santos Jadriane A. Xavier Felipe C. da Silva J. P. Jose Merlin Marília O. F. Goulart H. P. Vasantha Rupasinghe 《Molecules (Basel, Switzerland)》2022,27(13)
The objective of this work was to investigate the antidiabetic, antiglycation, and antioxidant potentials of ethanolic extract of seeds of Brazilian Passiflora edulis fruits (PESE), a major by-product of the juice industry, and piceatannol (PIC), one of the main phytochemicals of PESE. PESE, PIC, and acarbose (ACB) exhibited IC50 for alpha-amylase, 32.1 ± 2.7, 85.4 ± 0.7, and 0.4 ± 0.1 µg/mL, respectively, and IC50 for alpha-glucosidase, 76.2 ± 1.9, 20.4 ± 7.6, and 252 ± 4.5 µg/mL, respectively. The IC50 of PESE, PIC, and sitagliptin (STG) for dipeptidyl-peptidase-4 (DPP-4) was 71.1 ± 2.6, 1137 ± 120, and 0.005 ± 0.001 µg/mL, respectively. PESE and PIC inhibited the formation of advanced glycation end-products (AGE) with IC50 of 366 ± 1.9 and 360 ± 9.1 µg/mL for the initial stage and 51.5 ± 1.4 and 67.4 ± 4.6 µg/mL for the intermediate stage of glycation, respectively. Additionally, PESE and PIC inhibited the formation of β-amyloid fibrils in vitro up to 100%. IC50 values for 1,1-diphenyl-2-picrylhydrazyl radical (DPPH•) scavenging activity of PESE and PIC were 20.4 ± 2.1, and 6.3 ± 1.3 µg/mL, respectively. IC50 values for scavenging hypochlorous acid (HOCl) were similar in PESE, PIC, and quercetin (QCT) with values of 1.7 ± 0.3, 1.2 ± 0.5, and 1.9 ± 0.3 µg/mL, respectively. PESE had no cytotoxicity to the human normal bronchial epithelial (BEAS-2B), and alpha mouse liver (AML-12) cells up to 100 and 50 µg/mL, respectively. However, 10 µg/mL of the extract was cytotoxic to non-malignant breast epithelial cells (MCF-10A). PESE and PIC were found to be capable of protecting cultured human cells from the oxidative stress caused by the carcinogen NNKOAc at 100 µM. The in vitro evidence of the inhibition of alpha-amylase, alpha-glucosidase, and DPP-4 enzymes as well as antioxidant and antiglycation activities, warrants further investigation of the antidiabetic potential of P. edulis seeds and PIC. 相似文献
156.
Dr. Merlin Kleoff Patrick Voßnacker Prof. Dr. Sebastian Riedel 《Angewandte Chemie (International ed. in English)》2023,62(17):e202216586
Chlorine plays a central role for the industrial production of numerous materials with global relevance. More recently, polychlorides have been evolved from an area of academic interest to a research topic with enormous industrial potential. In this minireview, the value of trichlorides for chlorine storage and chlorination reactions are outlined. Particularly, the inexpensive ionic liquid [NEt3Me][Cl3] shows a similar and sometimes even advantageous reactivity compared to chlorine gas, while offering a superior safety profile. Used as a chlorine storage, [NEt3Me][Cl3] could help to overcome the current limitations of storing and transporting chlorine in larger quantities. Thus, trichlorides could become a key technique for the flexibilization of the chlorine production enabling an exploitation of renewable, yet fluctuating, electrical energy. As the loaded storage, [NEt3Me][Cl3], is a proven chlorination reagent, it could directly be employed for downstream processes, paving the path to a more practical and safer chlorine industry. 相似文献