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891.
892.
Janis Fricke Claudius Lenz Jonas Wick Felix Blei Prof. Dr. Dirk Hoffmeister 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(4):897-903
The fungal genus Psilocybe and other genera comprise numerous mushroom species that biosynthesize psilocybin (4-phosphoryloxy-N,N-dimethyltryptamine). It represents the prodrug to its dephosphorylated psychotropic analogue, psilocin. The colloquial term “magic mushrooms” for these fungi alludes to their hallucinogenic effects and to their use as recreational drugs. However, clinical trials have recognized psilocybin as a valuable candidate to be developed into a medication against depression and anxiety. We here highlight its recently elucidated biosynthesis, the concurrently developed concept of enzymatic in vitro and heterologous in vivo production, along with previous synthetic routes. The prospect of psilocybin as a promising therapeutic may entail an increased demand, which can be met by biotechnological production. Therefore, we also briefly touch on psilocybin's therapeutic relevance and pharmacology. 相似文献
893.
Jonas Kiessling 《Israel Journal of Mathematics》2012,191(1):483-505
In this paper we prove certain properties of cellular and acyclic classes of chain complexes of modules over a commutative Noetherian ring. In particular, we show that if X is finite and belongs to some cellular class C, then Σ n H n X also belongs to C, for every n. 相似文献
894.
Dr. Antony E. Fernandes Dr. Ali Dirani Cécile d'Haese Gladys Deumer Dr. Weiming Guo Dr. Peter Hensenne Fady Nahra Dr. Xavier Laloyaux Prof. Vincent Haufroid Prof. Bernard Nysten Prof. Olivier Riant Prof. Alain M. Jonas 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(50):16226-16233
Polymer brushes (PBs) have been used as supports for the immobilization of palladium complexes on silicon surfaces. The polymers were grown by surface‐initiated atom‐transfer radical polymerization (SI‐ATRP) and postdecorated with dipyridylamine (dpa) ligands. The pendant dpa units were in turn complexed with [Pd(OAc)2] to afford hybrid catalytic surfaces. A series of catalytic samples of various thicknesses (ca. 20–160 nm) and associated palladium loadings (ca. 10–45 nmol cm?2) were obtained by adjusting the SI‐ATRP reaction time and characterized by ellipsometry, X‐ray reflectivity, X‐ray photoelectron spectroscopy, and inductively coupled plasma mass spectrometry (ICP‐MS). ICP‐MS revealed a near‐linear relationship between thickness of the polymer brush and palladium content, which confirmed the robustness of the preparation and postmodification sequence presented herein, rendering possible the creation of functional architectures with predefined catalytic potential. The activities of the catalytic PBs were determined by systematically exploring a full range of substrate‐to‐catalyst ratios in a model palladium(0)‐catalyzed reaction. Quantitative transformations were observed for loadings down to 0.03 mol % and a maximum turnover number (TON) of around 3500 was established for the system. Comparison of the catalytic performances evidenced a singular influence of the thickness on conversions and TONs. The limited recyclability of the hairy catalysts has been attributed to palladium leaching. 相似文献
895.
Hatch CD Wiese JS Crane CC Harris KJ Kloss HG Baltrusaitis J 《Langmuir : the ACS journal of surfaces and colloids》2012,28(3):1790-1803
Water adsorption on kaolinite, illite, and montmorillonite clays was studied as a function of relative humidity (RH) at room temperature (298 K) using horizontal attenuated total reflectance (HATR) Fourier transform infrared (FTIR) spectroscopy equipped with a flow cell. The water content as a function of RH was modeled using the Brunauer, Emmett, and Teller (BET) and Freundlich adsorption isotherm models to provide complementary multilayer adsorption analysis of water uptake on the clays. A detailed analysis of model fit integrity is reported. From the BET fit to the experimental data, the water content on each of the three clays at monolayer (ML) water coverage was determined and found to agree with previously reported gravimetric data. However, BET analysis failed to adequately describe adsorption phenomena at RH values greater than 80%, 50%, and 70% RH for kaolinite, illite, and montmorillonite clays, respectively. The Freundlich adsorption model was found to fit the data well over the entire range of RH values studied and revealed two distinct water adsorption regimes. Data obtained from the Freundlich model showed that montmorillonite has the highest water adsorption strength and highest adsorption capacity at RH values greater than 19% (i.e., above ML water adsorption) relative to the kaolinite and illite clays. The difference in the observed water adsorption behavior between the three clays was attributed to different water uptake mechanisms based on a distribution of available adsorption sites. It is suggested that different properties drive water adsorption under different adsorption regimes resulting in the broad variability of water uptake mechanisms. 相似文献
896.
Jonas Rimas 《Linear algebra and its applications》2012,436(9):3493-3506
In this paper, we give the eigenvalue decomposition for odd order tridiagonal 2-Toeplitz matrix and derive the explicit expression for integer powers of such matrix. 相似文献
897.
A. Dubickas and C. Smyth introduced the metric Mahler measure
M1(a) = inf{?n=1N M(an): N ? \mathbb N, a1 ?aN = a},M_1(\alpha) = \inf\bigg\{\sum_{n=1}^N M(\alpha_n): N \in {\mathbb {N}}, \alpha_1 \cdots \alpha_N =\alpha\bigg\}, 相似文献
898.
899.
Two isostructural, nonclassical Co(H(2)) complexes are prepared from their Co(N(2)) precursors using tris(phosphino)silyl and tris(phosphino)borane ancillary ligands. Comproportionation of CoBr(2) and Co metal in the presence of TPB (tris-(o-diisopropylphophinophenyl)borane) gives (TPB)CoBr (4). One-electron reduction of 4 triggers N(2) binding to give (TPB)Co(N(2)) (2-N(2)) which is isostructural to previously reported [SiP(3)]Co(N(2)) (1-N(2)) ([SiP(3)] = tris-(o-diisopropylphosphinophenyl)silyl). Both 1-N(2) and 2-N(2) react with 1 atm H(2) to generate thermally stable H(2) complexes 1-H(2) and 2-H(2), respectively. Both complexes are characterized by a suite of spectroscopic techniques in solution and by X-ray crystallography. The H(2) and N(2) ligands in 2-H(2) and 2-N(2) are labile under ambient conditions and the binding equilibria are observable by temperature-dependent UV/vis. A van't Hoff analysis allows for the ligand binding energetics to be determined (H(2): ΔH(o) = -12.5(3) kcal mol(-1) and ΔS(o) = -26(3) cal K(-1) mol(-1); N(2): ΔH(o) = -13.9(7) kcal mol(-1) and ΔS(o) = -32(5) cal K(-1) mol(-1)). 相似文献
900.
We herein present a series of d(7) trimethylphosphine complexes of group 9 metals that are chelated by the tripodal tetradentate tris(phosphino)silyl ligand [SiP(iPr)(3)]H ([SiP(iPr)(3)] = (2-iPr(2)PC(6)H(4))(3)Si(-)). Both electron paramagnetic resonance (EPR) simulations and density functional theory (DFT) calculations indicate largely metalloradical character. These complexes provide a rare opportunity to compare the properties between the low-valent metalloradicals of the second- and third-row transition metals with the corresponding first-row analogues. 相似文献
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