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71.
Shahzad Hussain Abdellatif A. Mohamed Mohamed S. Alamri Mohamed A. Ibraheem Akram A. Abdo Qasem Tawfiq Alsulami Ibrahim A. Ababtain 《Molecules (Basel, Switzerland)》2022,27(3)
This study was planned to explore the locally available natural sources of gum hydrocolloids as a natural modifier of different starch properties. Corn (CS), sweet potato (SPS), and Turkish bean (TBS) starches were mixed with locally extracted native or acetylated cactus (CG) and acacia (AG) gums at 2 and 5% replacement levels. The binary mixtures (starch–gums) were prepared in water, freeze dried, ground to powder, and stored airtight. A rapid viscoanalyzer (RVA), differential scanning calorimeter (DSC), texture analyzer, and dynamic rheometer were used to explore their pasting, thermal, textural, and rheological properties. The presence of acetylated AG or CG increased the final viscosity (FV) in all three starches when compared to starch pastes containing native gums. Plain SPS dispersion had a higher pasting temperature (PT) than CS and TBS. The addition of AG or CG increased the PT of CS, SPS, and TBS. The thermograms revealed the overall enthalpy change of the starch and gum blends: TBS > SPS > CS. The peak temperature (Tp) of starches increased with increasing gum concentration from 2 to 5% for both AG and CG native and modified gums. When compared to the control gels, the addition of 2% CG, either native or modified, reduced the syneresis of starch gels. However, further addition (5% CG) increased the gels’ syneresis. Furthermore, the syneresis for the first cycle on the fourth day was higher than the second cycle on the eighth day for all starches. The addition of native and acetylated CG reduced the hardness of starch gels at all concentrations tested. All of the starch dispersions had higher G′ than G″ values, indicating that they were more elastic and less viscous with or without the gums. The apparent viscosity of all starch gels decreased as shear was increased, with profiles indicating time-dependent thixotropic behavior. All of the starch gels, with or without gums, showed a non-Newtonian shear thinning trend in the shear stress vs. shear rate graphs. The addition of acetylated CG gum to CS resulted in a higher activation energy (Ea) than the native counterparts and the control. More specifically, starch gels with a higher gum concentration (5%) provided greater Ea than their native counterparts. 相似文献
72.
Biqun Chen Karthikeyan Rajagopal Fatemeh Parastesh Hamed Azarnoush Sajad Jafari Iqtadar Hussain 《理论物理通讯》2020,72(10):105003-28
The economic and financial systems consist of many nonlinear factors that make them behave as the complex systems. Recently many chaotic finance systems have been proposed to study the complex dynamics of finance as a noticeable problem in economics. In fact, the intricate structure between financial institutions can be obtained by using a network of financial systems. Therefore, in this paper, we consider a ring network of coupled symmetric chaotic finance systems, and investigate its behavior by varying the coupling parameters. The results show that the coupling strength and range have significant effects on the behavior of the coupled systems, and various patterns such as the chimera and multi-chimera states are observed. Furthermore, changing the parameters' values, remarkably influences on the oscillators attractors. When several synchronous clusters are formed, the attractors of the synchronized oscillators are symmetric, but different from the single oscillator attractor. 相似文献
73.
Shamsa Munir Afzal Shah Abdur Rauf Amin Badshah Hidayat Hussain Zia-ur-Rehman Zahoor Ahmad 《Comptes Rendus Chimie》2013,16(12):1140-1146
The present work reports the redox mechanism of 5-hydroxynaphthalene-1,4-dione (HND), commonly known as juglone, in buffered aqueous media having 50% of ethanol. HND followed different mechanistic routes depending upon the pH of the media and more than one pKa were evaluated from the changes in the slope of the Ep vs. pH plot. The change of pH from acidic to neutral conditions was found to switch the mechanism from CEC to EE mechanism. Pulse techniques were utilized to determine the number of electrons involved in the oxidation and/or the reduction step and to ensure the nature of the redox process. Based upon the obtained results, an electrode reaction mechanism was proposed. Computational studies of HND supported the experimental results. UV-Visible spectroscopy was also employed for the detailed characterization of the compound in a wide range of pH and for the determination of its pKa. 相似文献
74.
Rasheed Ahmad Khera Munawar Hussain Nguyen Thai Hung Nadi Eleya Holger Feist Alexander Villinger Peter Langer 《Helvetica chimica acta》2012,95(3):469-482
Suzuki? Miyaura reactions of 2,3‐dibromo‐1H‐inden‐1‐one afforded a wide range of arylated 1H‐inden‐1‐ones. Sonogashira cross‐coupling reactions gave alkynylated indenones. The reactions proceeded with very good regioselectivity in the less sterically hindered and more electron‐deficient position 3. 相似文献
75.
High bit-rate (>10 Gb/s) signals are composed of very short pulses and propagation of such pulses through a semiconductor
optical amplifier (SOA) requires consideration of intraband phenomena. Due to the intraband effects, the propagating pulse
sees a fast recovering nonlinear gain which introduces less distortion in the pulse shape and spectrum of the output pulse
but introduces a positive chirping at the trailing edge of the pulse. 相似文献
76.
77.
Synthetic studies toward eletefine, a novel stephaoxocane alkaloid, were undertaken in an attempt to provide a general methodology to aid in the synthesis of other novel stephaoxocanes. An efficient construction of the AB ring system with increased functionality is described which presents a flexible approach to synthesizing the C and D rings of eletefine. 相似文献
78.
M. Sakhawat Hussain 《Journal of chemical crystallography》1986,16(1):91-99
The crystal and molecular structures of chloro(triphenylphosphineselenide)gold(I), [(C6H5)3PSe]AuCl, have been determined from three-dimensional X-ray intensity data collected on a CAD4 diffractometer. The compound crystallizes in the triclinic space groupPl witha=9.322(3),b=10.639(5),c=9.252(3) Å, =104.74(4), =99.52(3), =76.97(3)°, andZ=2. Atomic parameters were refined by full-matrix least-squares to anR value of 5.7% for 2591 observed reflections. This is one of the few known examples of linear gold(I) complexes having an Au-Se linkage. The Se-Au-Cl angle is 178.6(1)°, and the Au-Se and Au-Cl distances are 2.371(2) and 2.277(6) Å, respectively. As expected, the Au-Se bond length is 0.10–0.18 Å longer than the Au-S bond length observed in similar two-coordinate linear gold(I) complexes. 相似文献
79.
(+)-Parviflorine (), found in Lam. (Fumariaceae), is the first known glycosidic spirobenzylisoquinoline alkaloid. Its acid hydrolysis yields (+)-parfumine () and D-glucose. Klyne's rule indicates that is a β-D-glucoside. The absolute configuration shown in expressions is predominant among spirobenzylisoquinolines. A generalization has been drawn between plant source and the oxygenation pattern of ring C for the spirobenzylisoquinoline alkaloids. 相似文献
80.
Ahmad VU Hussain J Hussain H Farooq U Farmanullah Lodhi MA Choudhary MI 《Natural product research》2005,19(3):267-274
Two new myrsinol-type diterpene polyesters 3,5,13,17-tetra-O-acetyl-7-O-benzoyl-15-hydroxymyrsinol (1) and 3,5,13,17-tetra-O-acetyl-7-O-butanoyl-13-hydroxymyrsinol (2), with a tricyclic carbon skeleton have been isolated from Euphorbia decipiens Boiss. & Buhse. The structure elucidation of the isolated compounds was based primarily on HREIMS, EIMS, IR, UV, ID-, and 2D-NMR analyses, including COSY, HMQC, HMBC, and NOESY correlations. Compounds 1 and 2 also showed activity against urease enzyme. 相似文献