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131.
Federica Mancini Dr. M. Yagiz Unver Dr. Walid A. M. Elgaher Dr. Varsha R. Jumde Alaa Alhayek Dr. Peer Lukat Dr. Jennifer Herrmann Dr. Martin D. Witte Dr. Matthias Köck Prof. Dr. Wulf Blankenfeldt Prof. Dr. Rolf Müller Prof. Dr. Anna K. H. Hirsch 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(64):14585-14593
Kinetic target-guided synthesis represents an efficient hit-identification strategy, in which the protein assembles its own inhibitors from a pool of complementary building blocks via an irreversible reaction. Herein, we pioneered an in situ Ugi reaction for the identification of novel inhibitors of a model enzyme and binders for an important drug target, namely, the aspartic protease endothiapepsin and the bacterial β-sliding clamp DnaN, respectively. Highly sensitive mass-spectrometry methods enabled monitoring of the protein-templated reaction of four complementary reaction partners, which occurred in a background-free manner for endothiapepsin or with a clear amplification of two binders in the presence of DnaN. The Ugi products we identified show low micromolar activity on endothiapepsin or moderate affinity for the β-sliding clamp. We succeeded in expanding the portfolio of chemical reactions and biological targets and demonstrated the efficiency and sensitivity of this approach, which can find application on any drug target. 相似文献
132.
Walid A. Al-Shahib Alexander S. Dunn 《Journal of Dispersion Science and Technology》2013,34(2-3):175-182
Although a large number of methods are available for the determination of critical micelle concentrations many of these cannot be applied to the highest members of homologous series which are insufficiently soluble in water. The number of latex particles formed and consequently the rate of emulsion polymerization of such monomers as styrene which have only a very low solubility In water increase rapidly at the c.m.c. of the surfactant. When the surfactant is a salt which can be formed at the interface by dissolving the long-chain acid in the monomer and a slight excess of alkali in the water, observation of surfactant concentration at which this increase in particle number and polymerization rate takes place provides an experimental method for the determination of the c.m.c. which gives results in good agreement with expectation based on an extrapolation of results obtained by other methods on lower members of the series in the case of potassium docosanoate. 相似文献
133.
Quasi-static imbibition was simulated using random and correlated stochastic network models. Using the snap-off pore-scale
displacement observed by Lernormand et al. (1983) the effects of many parameters on relative permeabilities and residual saturation reported in the literature were
reproduced and explained. Increased relative permeabilities and decreased residual non-wetting phase saturation were the results
of an increased contact angle (Li and Wardlaw, 1986b; Gauglitz and Radke, 1990; Blunt et al., 1992; Mogensen and Stenby, 1998) a decreased pore–throat aspect ratio, the presence of long-range pore-pore size correlations
(Iaonnidis and Chatzis, 1993; Blunt, 1997a), or local pore–throat correlations (Jerauld and Salter, 1990; Iaonnidis and Chatzis,
1993). By modifying the level of snap-off, or its spatial distribution, these parameters varied the efficiency of the displacement
patterns and ultimately affect relative permeabilities and residual saturations. Mani and Mohanty (1999) performed simulations
on networks with infinite-ranged fractional Brownian motion (fBm) correlations and reported trends of relative permeabilities
and residual saturations that were opposite to others’ results (Ioannidis and Chatzis, 1993; Blunt, 1997a). Applying a cut-off
length to the fBm correlations reversed Mani and Mohanty’s trends to conform with the common observations. 相似文献
134.
Mostafa M. Ghorab Fatma A. Ragab Helmy I. Heiba Walid M. Ghorab 《Journal of heterocyclic chemistry》2011,48(6):1269-1279
Quinoline derivatives posses many types of biological activities and have been reported to show significant anticancer activity. There is a variety of mechanisms for the anticancer activity and the most distinguished mechanism is the inhibition of vascular epithelial growth factor receptor tyrosine kinase (VEGFRTK). Novel quinoline derivatives 6 , 7a , 7b , 7c , 8 , 9 , 10 , 11 , 12 and pyrimido[4,5‐b]quinoline derivatives 16 , 17 , 18 , 19 , 20 are reported herein. All the newly synthesized compounds were evaluated for their in vitro anticancer activity against human breast cancer cell line (MCF7) in which VEGFR is highly expressed. Compounds 6 and 7 with IC50 values of 8.5 μM and 21.9 μM were the most active compounds and exhibited cytotoxic activities higher than that of the reference drug doxorubicin (IC50= 32.02 μM). The most active compounds 6 and 7 were further evaluated for their ability to enhance the cell killing effect of γ‐radiation. J. Heterocyclic Chem., (2011). 相似文献
135.
Anwar H Joarder Walid S Al-Sabah 《International Journal of Mathematical Education in Science & Technology》2013,44(3):475-480
Conditional probability and statistical independence can be better explained with contingency tables. In this note some special cases of 2 X 2 contingency tables are considered. In turn an interesting insight into statistical dependence as well as independence of events is obtained. 相似文献
136.
Wireless Networks - Due to the rapid growth of the Internet and content development services, digital text has become the most extensively used type of media in digital communication. However,... 相似文献
137.
Basant A. Ali Walid Sharmoukh Mohamed M. Elnagar Zeinab M. Hassan Nageh K. Allam 《应用有机金属化学》2019,33(1)
The quality of emission spectra of metal complexes gives good insights into their performance in many optoelectronic applications. Herein, the effect of the number and position of various ligand structures on the emission spectra of Ru bipyridine complexes was studied. Specifically, the use of a different number of withdrawing groups (COOH) was investigated in detail. The complexes were first investigated using density functional theory (DFT) and time‐dependent DFT calculations and then confirmed experimentally. The bandgap energy, reactivity, emission spectra and Stokes shift were found to depend on the number and position of the withdrawing groups attached to the Ru(bpy)22+ complexes. Upon increasing the number of withdrawing groups, the electrons were found to be withdrawn from the carbon orbitals and resonated to reach the metal, and accumulated around it, thus enhancing the metal‐to‐ligand charge transfer mechanism instead of the ligand‐to‐ligand charge transfer mechanism. The complexes with more withdrawing groups showed spectra with more intense emission peaks with shorter lifetime, indicating the enhancement in the photoactivity of the complexes. Ligands with ring nitrogens with two COOH groups showed the greatest effect on the enhancement of the emission spectra with a lifetime of 0.5359 ns. The resulting collective emission spectra covered a wide wavelength range, making the investigated complexes a good choice for many optoelectronic applications. 相似文献
138.
139.
Walid Al-Maksoud Julien Mesnager Farouk Jaber Catherine Pinel Laurent Djakovitch 《Journal of organometallic chemistry》2009,694(20):3222-3231
Pd-catalysed procedures for the direct Heck arylation of diethyl vinylphosphonate with various aryl or heteroaryl halides toward the synthesis of diethyl 2-(aryl)vinylphosphonates are reported. Several homogeneous catalytic systems (i.e. Herrmann palladacycle, Nolan (NHC)-palladium catalyst, Pd(OAc)2/PPh3) were used and compared within the study. High conversions and selectivities were achieved under optimised conditions (2 mol% [Pd], NMP, K2CO3, 140 °C) whatever the homogeneous catalyst used. 相似文献
140.
In this paper, we study the Riesz basis property and the problem of stabilization of two vibrating strings connected by a point mass with variable physical coefficients under a boundary feedback control acts at one extreme point and Dirichlet boundary condition on the other end. It is shown that the system has a sequence of generalized eigenfunctions which forms a Riesz basis for the state Hilbert space. By a detailed spectral analysis, it is proved that this hybrid system is asymptotically stable but not exponentially stable. 相似文献