Mathematische Semesterberichte - Die Spielidee des Monopoly-Spiels ist mehr als 100 Jahre alt. Ein Grund für den beständigen Erfolg ist die Anpassungsfähigkeit der Spielidee.... 相似文献
Journal of Optimization Theory and Applications - We consider a distributionally robust formulation of stochastic optimization problems arising in statistical learning, where robustness is with... 相似文献
Positivity - We prove new characterisations of exponential stability for positive linear discrete-time systems in ordered Banach spaces, in terms of small-gain conditions. Such conditions have... 相似文献
Human blood group A and B glycosyltransferases (GTA, GTB) are retaining glycosyltransferases, requiring a catalytic mechanism that conserves the anomeric configuration of the hexopyranose moiety of the donor substrate (UDP-GalNAc, UDP-Gal). Previous studies have shown that GTA and GTB cycle through structurally distinct states during catalysis. Here, we link binding and release of substrates, substrate-analogs, and products to transitions between open, semi-closed, and closed states of the enzymes. Methyl TROSY based titration experiments in combination with zz-exchange experiments uncover dramatic changes of binding kinetics associated with allosteric interactions between donor-type and acceptor-type ligands. Taken together, this highlights how allosteric control of on- and off-rates correlates with conformational changes, driving catalysis to completion. 相似文献
Millions of diverse molecules constituting the lipidome act as important signals within cells. Of these, cardiolipin (CL) and phosphatidylethanolamine (PE) participate in apoptosis and ferroptosis, respectively. Their subcellular distribution is largely unknown. Imaging mass spectrometry is capable of deciphering the spatial distribution of multiple lipids at subcellular levels. Here we report the development of a unique 70 keV gas-cluster ion beam that consists of (CO2)n+(n>10 000) projectiles. Coupled with direct current beam buncher-time-of-flight secondary-ion mass spectrometry, it is optimized for sensitivity towards high-mass species (up to m/z 3000) at high spatial resolution (1 μm). In combination with immunohistochemistry, phospholipids, including PE and CL, have been assessed in subcellular compartments of mouse hippocampal neuronal cells and rat brain tissue. 相似文献
Simultaneous incorporation of both CoII and CoIII ions within a new thioether S‐bearing phenol‐based ligand system, H3L (2,6‐bis‐[{2‐(2‐hydroxyethylthio)ethylimino}methyl]‐4‐methylphenol) formed [Co5] aggregates [CoIICoIII4L2(μ‐OH)2(μ1,3‐O2CCH3)2](ClO4)4?H2O ( 1 ) and [CoIICoIII4L2(μ‐OH)2(μ1,3‐O2CC2H5)2](ClO4)4?H2O ( 2 ). The magnetic studies revealed axial zero‐field splitting (ZFS) parameter, D/hc=?23.6 and ?24.3 cm?1, and E/D=0.03 and 0.00, respectively for 1 and 2 . Dynamic magnetic data confirmed the complexes as SIMs with Ueff/kB=30 K ( 1 ) and 33 K ( 2 ), and τ0=9.1×10?8 s ( 1 ), and 4.3×10?8 s ( 2 ). The larger atomic radius of S compared to N gave rise to less variation in the distortion of tetrahedral geometry around central CoII centers, thus affecting the D and Ueff/kB values. Theoretical studies also support the experimental findings and reveal the origin of the anisotropy parameters. In solutions, both 1 and 2 which produce {CoIII2(μ‐L)} units, display solvent‐dependent catechol oxidation behavior toward 3,5‐di‐tert‐butylcatechol in air. The presence of an adjacent CoIII ion tends to assist the electron transfer from the substrate to the metal ion center, enhancing the catalytic oxidation rate. 相似文献
In this paper, the effect of pH, i.e. acid and alkali was investigated on thermal stability of ligno-cellulosic polymeric fibrous (jute) material. The jute fabric was subjected to treatment under different pH, namely 4.5, 7, 10, 12, i.e. in acidic, neutral and alkaline conditions followed by drying prior to any thermal and physical characterization. The improvement in the thermal stability of jute to flame was measured in terms of limiting oxygen index value, vertical flammability and temperature profile of burning zone. Likewise thermo-gravimetry, differential scanning calorimetry and cone calorimeter analysis were also used to elucidate the improvement in thermal stability of the treated fabric. The changes in heat release rate, mass loss rate, heat of combustion, smoke production, etc., in the untreated and treated sample were measured in detail in cone calorimeter. Only the alkali-treated jute fabric samples showed profound improvement in thermal stability.
In this work, we report an efficient method to produce pure hollow silica spheres (HSS) using phenyltrimethoxysilane (PTMS) compound. The production of HSS was carried out via hydrolysis of PTMS in the aqueous media and followed by a condensation reaction to form silica spheres with phenyl groups. The product was then calcined to remove phenyl groups and obtain pure silica spheres with >95% fine structure. The chemical nature of pure silica was confirmed by Fourier transforms infrared spectroscopy. The calcined HSS were stable beyond the temperature of 900 °C as confirmed by thermal gravimetric analysis (TGA). The calcined spheres preserved their spherical appearance and hollow core as shown by SEM and TEM micrographs. Interestingly, the average size of the spheres was reduced significantly after calcination from 760 to 510 nm, confirming further the removal of phenyl groups. The calcined HSS offered much higher surface area (As) when analysed by BET; As for calcined product was ~406 and mere ~4.8 m2/g for uncalcined HSS. Finally, drug release study of cisplatin/HSS showed over 45% of steady cumulative release for 72 h. The prepared HSS can be dispersed in water opening the possibility of many novel bio/non-bio applications. 相似文献