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841.
Masood SarwarAugustin M. Madalan Franceso LloretMiguel Julve Marius Andruh 《Polyhedron》2011,30(14):2414-2420
The mononuclear high-spin iron(III) complexes [Fe(3-MeOsalpn)Cl(H2O)] (1) and [Fe(3-MeOsalpn)(NCS)(H2O)]·0.5CH3CN (2) and the tetranuclear oxo-bridged compound [{Fe(3-MeOsalpn)Gd(NO3)3}2(μ-O)]·CH3CN (3) [3-MeOsalpn2− = N,N′-propylenebis(3-methoxysalicylideneiminate)] have been prepared and magneto-structurally characterised. The iron(III) ion in 1 and 2 is six-coordinated in a somewhat distorted octahedral surrounding with the two phenolate-oxygens and two imine-nitrogens from the Schiff-base building the equatorial plane and a water (1 and 2) and a chloro (1)/thiocyanate-nitrogen (2) in the axial positions. The neutral mononuclear units of 1 and 2 are assembled into centrosymmetric dinuclear motifs through hydrogen bonds between the axially coordinated water molecule of one iron centre and methoxy-oxygen atoms from the Schiff-base of the adjacent iron atom. The values of the intradimer metal-metal distance within the supramolecular dimers are 4.930 (1) and 4.878 Å (2). The tetranuclear of 3 can be described as two {FeIII(3-MeOsalpn)} units connected through an oxo-bridge, each one hosting a [GdIII(NO3)3] entity in the outer cavity defined by the two phenolate- and two methoxy-oxygen atoms. The values of the intramolecular Fe?Fe and Fe?Gd distances in 3 are 3.502 and 3.606 Å, respectively. The analysis of the magnetic data of 1-3 in the temperature range 1.9-300 K shows the occurrence of weak intermolecular antiferromagnetic interactions in 1 and 2 [J = −0.76 (1) and −0.75 cm−1 (2) with the Hamiltonian defined as H = −JSFe1·SFe1] whereas two intramolecular antiferromagnetic interactions coexist in 3, one very strong between the two iron(III) ions (J1) through the oxo bridge and the other much weaker between the iron(III) and the Gd(III) ions (J2) across the double phenoxo oxygens [J1 = −275 cm−1 and J2 = −3.25 cm−1, the Hamiltonian being defined as H=-J1SFe1·SFe1′-J2(SFe1·SGd1+SFe1′·SGd1′)]. These values are analysed in the light of the structural data and compared with those of related systems. 相似文献
842.
Marina Dana Ţopa Norbert Toma Botond Sandor Kirei Ioana Homana Marius Neag Gilbert De Mey 《Acoustical Physics》2011,57(2):199-207
The paper presents the acoustics analysis of three different enclosed spaces. These spaces (rooms) have different geometrical
shapes and sizes and serve for different purposes. The early decay time, reverberation time, clarity and center time are evaluated
with Dirac, WinMLS, Aurora and Caracad software using simple, low-cost equipment. The listed acoustic parameters were determined
using linear sine sweep and impulsive sources. Comparisons between experimental measurements, simulations and analytic results
were done. The room impulse response measurement proved to be the most reliable method to evaluate the properties of different
rooms even if the measurements are perturbed by non-idealities of the low-cost equipment. 相似文献
843.
Garrett DS Gronenborn AM Clore GM 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2011,(2):364-365
The Contour Approach to Peak Picking was developed to aid in the analysis and interpretation and of multidimensional NMR spectra of large biomolecules. In essence, it comprises an interactive graphics software tool to computationally select resonance positions in heteronuclear, 3- and 4D spectra. 相似文献
844.
Objectives
To objectively identify possible differences in the signal characteristics of benign and malignant soft tissue masses (STM) on magnetic resonance (MR) images by means of texture analysis and to determine the value of these differences for computer-assisted lesion classification.Method
Fifty-eight patients with histologically proven STM (benign, n=30; malignant, n=28) were included. STM texture was analyzed on routine T1-weighted, T2-weighted and short tau inversion recovery (STIR) images obtained with heterogeneous acquisition protocols. Fisher coefficients (F) and the probability of classification error and average correlation coefficients (POE+ACC) were calculated to identify the most discriminative texture features for separation of benign and malignant STM. F>1 indicated adequate discriminative power of texture features. Based on the texture features, computer-assisted classification of the STM by means of k-nearest-neighbor (k-NN) and artificial neural network (ANN) classification was performed, and accuracy, sensitivity and specificity were calculated.Results
Discriminative power was only adequate for two texture features, derived from the gray-level histogram of the STIR images (first and 10th gray-level percentiles). Accordingly, the best results of STM classification were achieved using texture information from STIR images, with an accuracy of 75.0% (sensitivity, 71.4%; specificity, 78.3%) for the k-NN classifier, and an accuracy of 90.5% (sensitivity, 91.1%; specificity, 90.0%) for the ANN classifier.Conclusion
Texture analysis revealed only small differences in the signal characteristics of benign and malignant STM on routine MR images. Computer-assisted pattern recognition algorithms may aid in the characterization of STM, but more data is necessary to confirm their clinical value. 相似文献845.
Nonlinear Dynamics - We analyze the effect of synaptic noise on the dynamics of the FitzHugh–Nagumo (FHN) neuron model. In our deterministic parameter regime, a limit cycle solution cannot... 相似文献
846.
Raphael?ZinggEmail authorView authors OrcID profile Marius?Fischer 《Journal of nanoparticle research》2018,20(10):267
Despite all predictions and promises, nanotechnology still seems to be more of an emerging science than a fully fledged revolution. More often than not, the patent system is blamed for this, supposedly tangling up nanotechnology in an impenetrable thicket of exclusionary rights instead of setting it free. Drawing on methods of complex network analysis, we provide empirical evidence suggesting that, at least in Europe, there is actually no patent thicket present in nanotechnology. Yet, the situation appears to be different in the USA. 相似文献
847.
Jonas Kilian Marlon Millard Marius Ozenil Dominik Krause Khadija Ghaderi Wolfgang Holzer Ernst Urban Helmut Spreitzer Wolfgang Wadsak Marcus Hacker Thierry Langer Verena Pichler 《Molecules (Basel, Switzerland)》2022,27(10)
The muscarinic acetylcholine receptor family is a highly sought-after target in drug and molecular imaging discovery efforts aimed at neurological disorders. Hampered by the structural similarity of the five subtypes’ orthosteric binding pockets, these efforts largely failed to deliver subtype-selective ligands. Building on our recent successes with arecaidine-derived ligands targeting M1, herein we report the synthesis of a related series of 11 hydroxylated arecaidine esters. Their physicochemical property profiles, expressed in terms of their computationally calculated CNS MPO scores and HPLC-logD values, point towards blood–brain barrier permeability. By means of a competitive radioligand binding assay, the binding affinity values towards each of the individual human mAChR subtypes hM1–hM5 were determined. The most promising compound of this series 17b was shown to have a binding constant towards hM1 in the single-digit nanomolar region (5.5 nM). Similar to our previously reported arecaidine-derived esters, the entire series was shown to act as hM1R antagonists in a calcium flux assay. Overall, this study greatly expanded our understanding of this recurring scaffolds’ structure–activity relationship and will guide the development towards highly selective mAChRs ligands. 相似文献
848.
Roxana Ghiulai Marius Mioc Roxana Racoviceanu Alexandra Prodea Andreea Milan Dorina Coricovac Cristina Dehelean tefana Avram Alina D. Zamfir Cristian V. A. Munteanu Viviana Ivan Codrua oica 《Molecules (Basel, Switzerland)》2022,27(21)
Betulinic acid (BA) has been extensively studied in recent years mainly for its antiproliferative and antitumor effect in various types of cancers. Limited data are available regarding the pharmacokinetic profile of BA, particularly its metabolic transformation in vivo. In this study, we present the screening and structural investigations by ESI Orbitrap MS in the negative ion mode and CID MS/MS of phase I and phase II metabolites detected in mouse plasma after the intraperitoneal administration of a nanoemulsion containing BA in SKH 1 female mice. Obtained results indicate that the main phase I metabolic reactions that BA undergoes are monohydroxylation, dihydroxylation, oxidation and hydrogenation, while phase II reactions involved sulfation, glucuronidation and methylation. The fragmentation pathway for BA and its plasma metabolites were elucidated by sequencing of the precursor ions by CID MS MS experiments. 相似文献
849.
Marius D. R. Lutz Hongyu Zhong Nils Trapp Bill Morandi 《Helvetica chimica acta》2023,106(4):e202200199
We report the synthesis of coordinatively unsaturated cationic rhodium complexes bearing the sterically encumbered electron-rich NHC ligand IPr*OMe. The COD (1,5-cyclooctadiene) complex [Rh(IPr*OMe)(COD)]BF4 adopts a tilted, pseudo-square planar coordination geometry, where bonding to the ipso-carbon of the NHC aryl substituent was observed in the solid state. Hydrogenation of this complex afforded a metastable dihydride complex [Rh(IPr*OMe)(H)2]BF4 with an unusual internal coordination to an arene of the ligand. In the absence of a hydrogen atmosphere, spontaneous reductive elimination of H2 afforded a rhodium complex [Rh(IPr*OMe)]BF4 with a single chelating ligand that stabilizes the highly unsaturated metal by two-fold π-face donation as suggested by NMR spectroscopy and computational studies. This unusual complex might serve as a versatile precatalyst for a variety of transformations. 相似文献