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31.
Mziyanda Mbaba Laura M. K. Dingle Ayanda I. Zulu Dustin Laming Tarryn Swart Jo-Anne de la Mare Heinrich C. Hoppe Adrienne L. Edkins Setshaba D. Khanye 《Molecules (Basel, Switzerland)》2021,26(5)
A tailored series of coumarin-based ferrocenyl 1,3-oxazine hybrid compounds was synthesized and investigated for potential antiparasitic activity, drawing inspiration from the established biological efficacy of the constituent chemical motifs. The structural identity of the synthesized compounds was confirmed by common spectroscopic techniques: NMR, HRMS and IR. Biological evaluation studies reveal that the compounds exhibit higher in vitro antiparasitic potency against the chemosensitive malarial strain (3D7 P. falciparum) over the investigated trypanosomiasis causal agent (T. b. brucei 427) with mostly single digit micromolar IC50 values. When read in tandem with the biological performance of previously reported structurally similar non-coumarin, phenyl derivatives (i.e., ferrocenyl 1,3-benzoxazines and α-aminocresols), structure-activity relationship analyses suggest that the presence of the coumarin nucleus is tolerated for biological activity though this may lead to reduced efficacy. Preliminary mechanistic studies with the most promising compound (11b) support hemozoin inhibition and DNA interaction as likely mechanistic modalities by which this class of compounds may act to produce plasmocidal and antitrypanosomal effects. 相似文献
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The crystal spectrum of Ni en3(NO3)2 is assigned. At low temperatures, the development of discrete vibrational structure has allowed the identification of the transition3 A 2→1 A 1. This leads to the proposal that a major portion of the spectral band intensities arises from vibronic contributions in the molecular symmetry group. This agrees with our earlier observations on the [Co en3]3+ ion and the result is likely to be applicable to all tris ethylenediamine metal complexes. 相似文献
34.
Summary Calculations were done on ground and excited states of C2, C
2
+
, C
2
–
, N2, N
2
+
, O2, O
2
+
, O
2
–
, CO, CO+, CO2+, and CO– using contracted well-tempered basis sets. The (14s 10p) basis sets were augmented with threed, one or twof, and oneg functions. Total energies, orbital energies, and spectroscopic constants were compared with the best available computational data. 相似文献
35.
Unsteady flow in a semi-infinite contracting or expanding pipeis reinvestigated using long series analysis. The proposed seriesmethod is useful in analysing the problem for a moderately largeconstant ( = aa/, where a = a(t), the radius of the pipe isa function of time, a(t) is the velocity of the wall, and iskinematic viscosity). For positive values of (expansion ofthe pipe) accuracy of the series representing shear stress andpressure gradient is increased from = 2.89 to = 6.0 by extractingthe singularity followed by completion of the series. For negativevalues of (contraction of the pipe), we revert the series whichresults into the increase of the region of validity of the transposedseries from = -25.0 to = -2.89. Later we use Padé approximantsfor summing them. Also, the asymptotic solution for large valuesof is obtained and it agrees closely with pure numerical valuesof shear stress at the wall and pressure gradient. 相似文献
36.
R. B. Dingle 《Applied Scientific Research》1954,3(1):69-99
Summary Series expansions are derived for the integrals determining the surface impedance of a metal when the skin effect is anomalous. 相似文献
37.
We report a systematic increase of the linewidth of luminescence, absorption and excitation spectra of undoped Multi-Quantum structures with decreasing layer thickness. This broadening is interpreted as due to the island-like structure of the interfaces. A very simple model assuming islands with a one monolayer height and a lateral size ? 300 Å gives very good agreement with the reported linewidths. 相似文献
38.
DP Phillips RN Dingle SE Hall M Jang 《The Journal of the Acoustical Society of America》2012,132(1):EL22-EL28
Two experiments measured human sensitivity to temporal jitter in 25-click trains with inter-click intervals (ICIs) between 5 and 100 ms. In a naturalistic experiment using wideband clicks, jitter thresholds were a nonmonotonic function of ICI, peaking for ICIs near 40-60 ms. In a subsequent experiment, clicks were high-passed and presented against a low-frequency noise masker. Jitter threshold vs ICI functions lost the positive slope over short ICIs but retained the negative slope at long ICIs. The same behavior was seen in click rate discrimination tasks. Different processes mediate regularity analysis for click trains with ICIs above and below 40-60 ms. 相似文献