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81.
Nicolas A. Frank Mri Szles Sergi H. Akone Sari Rasheed Stephan Hüttel Simon Frewert Mostafa M. Hamed Jennifer Herrmann Sren M. M. Schuler Anna K. H. Hirsch Rolf Müller 《Molecules (Basel, Switzerland)》2021,26(16)
Myxobacteria represent a viable source of chemically diverse and biologically active secondary metabolites. The myxochelins are a well-studied family of catecholate-type siderophores produced by various myxobacterial strains. Here, we report the discovery, isolation, and structure elucidation of three new myxochelins N1–N3 from the terrestrial myxobacterium Corallococcus sp. MCy9049, featuring an unusual nicotinic acid moiety. Precursor-directed biosynthesis (PDB) experiments and total synthesis were performed in order to confirm structures, improve access to pure compounds for bioactivity testing, and to devise a biosynthesis proposal. The combined evaluation of metabolome and genome data covering myxobacteria supports the notion that the new myxochelin congeners reported here are in fact frequent side products of the known myxochelin A biosynthetic pathway in myxobacteria. 相似文献
82.
Junko Fujimoto Sari Hayashi Hideyuki Kainuma Kazuhiro Manseki Taro Udagawa Hidekazu Miyaji 《化学:亚洲杂志》2019,14(15):2567-2572
Artificial antenna complexes of metal‐coordinated bis(8‐hydroxyquinoline)‐substituted porphyrin networks that mimic antenna chromophores in plants were organized on titanium dioxide electrodes in photoelectrochemical cells. The generated photocurrents can be optimized according to the two ways of porphyrin self‐assembly due to the “antenna effect”: changing the number of assembled porphyrin monolayers and the number of generations of the metal‐coordinated porphyrin networks. 相似文献
83.
Y. Karaaslan B. Gisi S. Sakiroglu E. Kasapoglu H. Sari I. Sokmen 《Physics letters. A》2018,382(7):507-515
We study the influence of electric field on the electronic energy band structure, zero-temperature ballistic conductivity and optical properties of double quantum wire. System described by double-well anharmonic confinement potential is exposed to a perpendicular magnetic field and Rashba and Dresselhaus spin-orbit interactions. Numerical results show up that the combined effects of internal and external agents cause the formation of crossing, anticrossing, camel-back/anomaly structures and the lateral, downward/upward shifts in the energy dispersion. The anomalies in the energy subbands give rise to the oscillation patterns in the ballistic conductance, and the energy shifts bring about the shift in the peak positions of optical absorption coefficients and refractive index changes. 相似文献
84.
85.
Huseyin Sari Esin Kasapoglu Unal Yesilgul Serpil Sakiroglu Fatih Ungan Ismail Sökmen 《The European Physical Journal B - Condensed Matter and Complex Systems》2017,90(9):162
The effect of non-resonant intense laser field on the intersubband-related optical absorption coefficient and refractive index change in the asymmetric n-type double δ-doped GaAs quantum well is theoretically investigated. The confined energy levels and corresponding wave functions of this structure are calculated by solving the Schrödinger equation in the laser-dressed confinement potential within the framework of effective mass approximation. The optical responses are reported as a function of the δ-doped impurities density and the applied non-resonant intense laser field. Additionally, the calculated results also reveal that the non-resonant intense laser field can be used as a way to control the electronic and optical properties of the low dimensional semiconductor nano-structures. 相似文献
86.
Sari Mkinen Jaakko Hiidenhovi Xin Huang Amanda dos Santos Lima Luciana Azevedo Jari Setl Anna-Liisa Vlimaa Pirjo Mattila Daniel Granato 《Molecules (Basel, Switzerland)》2022,27(18)
This study aimed to produce bioactive protein hydrolysates from undervalued fish, namely Baltic herring, and its filleting by-products. Protein hydrolysates were produced with Alcalase and Flavourzyme to achieve effective hydrolysis. The hydrolysates were evaluated for chemical composition, molecular weight distribution, antioxidant capacity, dipeptidyl-peptidase 4 (DPP4) inhibitory activity, effects on cell proliferation and surface hydrophobicity. The protein content of the hydrolysates was high, from 86% to 91% (dm), while the fat content was low, from 0.3% to 0.4% (dm). The hydrolysates showed high DPP4 inhibition activities with IC50 values from 5.38 mg/mL to 7.92 mg/mL. The scavenging activity of the hydrolysates towards DPPH was low, but an intermediate Folin–Ciocalteu reducing capacity and Cu2+ chelating ability was observed. The solid phase extraction with Sep-Pak C18 cartridges increased the DPP4 inhibition activity and antioxidant capacity, indicating peptides’ crucial role in the bioactivities. The cytotoxicity of the hydrolysates was evaluated on the HCT8, IMR90, and A549 cell lines. The hydrolysates inhibited cell growth in the cancer and normal cells, although they did not reduce cell viability and were not lethal. Overall, our results indicate that protein hydrolysates from Baltic herring have potential as health-promoting foods and nutraceuticals, especially for enhancing healthy blood glucose regulation. 相似文献
87.
88.
Sari Kiviniemi Maija Nissinen Tanja Kolli Jorma Jalonen Kari Rissanen Jouni Pursiainen 《Journal of inclusion phenomena and macrocyclic chemistry》2001,40(1-2):153-159
Crown ether complexes of six-membered N-heteroaromatic cations and the closely related bicyclic purinium cation (6) have been studied by 1H NMR, mass spectrometric and crystallographic methods. The stability constants for the complexes were determined by 1H NMR titration in acetonitrile solution and the complexation stoichiometry by 1H NMR and ESI mass spectrometric methods. Altogether six crystal structures of complexes were determined to study the complexation in the solid state. Hydrogen bonding was observed to be the most important interaction for the complexation both in solution and in the solid state but – interactions also contribute to it. All crystal structures of the DB18C6 complexes with six-membered N-heteroaromatic cations, except for 4-hydroxypyridinium, are isomorphous to previously studied five-membered N-heteroaromatic cations and pyridinium complexes. Such a close resemblance is not observed in B18C6 and 18C6 complexes or DB18C6purinium (6). 相似文献
89.
Sari L McCarthy MC Schaefer HF Thaddeus P 《Journal of the American Chemical Society》2003,125(37):11409-11417
Highly correlated ab initio coupled-cluster theories (e.g., CCSD(T), CCSDT) were applied on the ground electronic states of Si(2)H(3) and Si(2)H(4), with substantive basis sets. A total of 10 isomers, which include mono- and dibridged structures, were investigated. Scalar relativistic corrections and zero-point vibrational energy corrections were included to predict reliable energetics. For Si(2)H(3), we predict an unanticipated monobridged H(2)Si-H-Si-like structure (C(s), (2)A') to be the lowest energy isomer, in constrast to previous studies which concluded that either H(3)Si-Si (C(s), (2)A') or near-planar H(2)Si-SiH (C(1), (2)A) is the global minimum. Our results confirm that the disilene isomer, H(2)Si-SiH(2), is the lowest energy isomer for Si(2)H(4) and that it has a trans-bent structure (C(2)(h), (1)A(g)). In addition to the much studied silylsilylene, H(3)Si-SiH, we also find that a new monobridged isomer H(2)Si-H-SiH (C(1), (1)A, designated 2c) is a minimum on the potential energy surface and that it has comparable stability; both isomers are predicted to lie about 7 kcal/mol above disilene. By means of Fourier transform microwave spectroscopy of a supersonic molecular beam, the rotational spectrum of this novel Si(2)H(4) isomer has recently been measured in the laboratory, as has that of the planar H(2)Si-SiH radical. Harmonic vibrational frequencies as well as infrared intensities of all 10 isomers were determined at the cc-pVTZ CCSD(T) level. 相似文献
90.
Reeta?ViitalaEmail author Mika?Jokinen Sari?Tuusa Jarl?B.?Rosenholm Harry?Jalonen 《Journal of Sol-Gel Science and Technology》2005,36(2):147-156
Amorphous, sol-gel derived SiO2 are known to biocompatible and bioresorbable materials. Bioresorbable materials have potential applications as implants or
injectable matrices in the controlled delivery of biologically active agents in the living tissue. Bioresorbable matrices
provide desirable properties, e.g., extra removal operations that have to be done with biostable matrices are avoided and
the release of large therapeutic molecules can be controlled by matrix degradation rather than by diffusion. New important
groups of drugs, such as biotechnically-produced peptides and proteins, are potential to be encapsulated in bioresorbable
SiO2, because they are typically larger in size and their direct oral administration without protecting matrix is difficult due
to digestion. The methods to achieve a wide range of SiO2 bioresorption rates (from days to months) are introduced in this study. This is done by a “conventional” alkoxy-based sol-gel
method at protein-friendly conditions by adjusting the precursor ratios, aging of the sol and by using different preparation
methods (casting, spray-drying and freeze-drying). The prepared morphologies include implantable monolithic sticks and injectable
microspheres. The importance of chemical structure is shown in comparison with the specific surface area and pore volume. 相似文献