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A. G. Gharib S. G. Mohseni M. Mohajer M. Gharib 《Journal of Radioanalytical and Nuclear Chemistry》2006,270(1):209-215
Summary Bioavailability and/or homeostasis of some essential trace elements such as zinc, iron, etc., in the presence of phytate,
fiber and calcium are subject to alteration. These factors were measured in this study for Iranian diets in a frame of a Coordinated
Research Project (CRP). However, the most prominent dietary factor in this regard is phytate. The phytate effect on zinc homeostasis
is a chemical phenomenon dependent physiologically on pH in the gastrointestinal tract at or near the sites of absorption.
Calcium is a synergistic coprecipitating factor in the complexation of zinc by phytate. Fiber has also a tendency to absorb
insoluble compounds in gastrointestinal tract including zinc, iron and many other trace elements. One of the most known clinical
observations regarding zinc deficiency was found in the rural area of the Fars province of Iran in the late 1950s at Shiraz
University. However, the molar ratio of [phytate] : [zinc] and [calcium] [phytate] : [zinc] in Iranian Diets in a recent study
are 7-17 and 150-800, respectively. The critical ratios of [phytate] : [zinc] of 10 or less will provide adequate zinc to
sustain homeostasis. 相似文献
3.
Bounouri Yassine Berkani Madjid Zamouche Abdelmalek Dańczak Anna Chojnacka Ida Rycerz Leszek 《Journal of Thermal Analysis and Calorimetry》2018,134(3):1589-1597
Thixoforming involves heating different types of alloys to the semisolid state at high heating rates and forming in die-casting machines or conventional presses. At temperatures higher than the solidus and lower than the liquidus, the mush metal behaves like a high-viscosity thixotropic material. Therefore, determining the thermodynamic behavior of the solid-to-liquid transition is paramount to control thixoforming processes. This article describes a simple, novel experimental setup based on differential thermal analysis (DTA) for analyzing the phase transitions in an alloy heated using high heating rates typical of industrial applications. A365 alloy was chosen to demonstrate the effectiveness of the method as the phase transformations for this alloy in semisolid materials (SSM) processing are well understood. Samples were heated to 750 °C using constant linear heating rates of 5, 10, 15, 20, 25, 50, 75, 100 and 125 °C min in a Norax 25 kW 8 kHz induction furnace with an Omron E5CK temperature controller. AISI 316 austenitic stainless steel was used as the inert reference. Comparison of the results of DTA using the proposed method and the results of simulation with Thermo-Calc® indicates that the proposed in situ DTA device and its method is suitable for analyzing phase transitions when high heating rates are used. 相似文献
4.
The present work attempts to study the mechanical properties and toughness behavior of a typical acrylic melamine clearcoat modified by a polyester‐amide hyperbranched polymer (HBP). Formulations were such that 0, 5, 10, 25 and 50% (molar percent) of total acrylic hydroxyl groups were stoichiometrically substituted by those of HBP. Bulk and surface of the clearcoats were studied by various mechanical techniques including hardness, tensile, dynamic mechanical thermal analysis (DMTA), nano‐indentation and scratch tests. In addition a scanning electron microscope (SEM) was utilized to observe the morphology of the fractured films. The bulk mechanical properties showed that a low loading (5 molar %) of HBP was sufficient to considerably increase the bulk hardness, cross‐linking density and toughness. DMTA and SEM results proved the occurrence of a single‐phase blend and that the shear deformation was the main toughening mechanism of HBP modified clearcoats. In general, it was revealed that the HBP not only could act as an excellent compatible toughening agent, but also maintained the clarity of the clearcoat and increased its scratch resistance. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
5.
A simple, efficient, and rapid method for high-yielding regioselective mono bromination of phenols and anilines has been achieved by treatment with N-bromasaccharin in the presence of a catalytic amount of tungstophosphoric acid. 相似文献
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The three-component reaction of 4-hydroxy-1-methyl-2(1H)-quinolinone, aromatic aldehydes and ethyl cyanoacetate was carried out in the presence of a catalytic amount of 4-dimethyl aminopyridine(DMAP) in aqueous ethanol. The reactions result in the formation of pyranoquinoline derivatives in excellent yields. Antibacterial activity has been evaluated against Gram positive and Gram negative bacteria for some of the synthesized compounds. The results indicated that these compounds are moderately effective against bacterial growth and their effectiveness is highest against Pseudomonas aeruginosa. 相似文献
8.
Leila Ghasempour Sakineh Asghari Mahmood Tajbakhsh Mojtaba Mohseni 《Journal of heterocyclic chemistry》2020,57(12):4136-4148
One-pot four-component reactions of phenacyl bromides, parabanic or thioparabanic acids, thiophenols, and triphenylphosphine in the presence of triethylamine afforded new derivatives of hydantoin or thiohydantoin in good to high yields (65%-90%). Their antibacterial activities were evaluated against two Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis) and two Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa). Among the synthesized compounds, the obtained products from 2-hydroxythiophenol exhibited higher antibacterial activity than those obtained from 2-aminothiophenol. Compound 9l including N,N′′-diphenyl thiohydantoin moiety showed the highest antibacterial activity (26.0 ± 01.4) against B subtilis, in comparison with other synthesized samples. The antioxidant activities of the synthesized hydantoins and thiohydantoins were investigated by DPPH radical-scavenging based on Blois method. The results showed that all the compounds have high DPPH inhibition potency (77.4%-83.9%) that it could be due to existence of heteroatoms with lone pair electrons and exchangeable protons on their NH2 and OH groups. 相似文献
9.
This paper proposes a new multi-criteria decision analysis (MCDA) model that uses a series of existing intuitive and analytical
methods to systematically capture both objective and subjective beliefs and preferences from a group of decision makers (DMs).
A defuzzification method that combines entropy and the theory of displaced ideal synthesizes crisp values from the DMs’ subjective
judgments. This approach assists the DMs in their selection process by plotting alternatives in a four quadrant graph and
considering their Euclidean distance from the “ideal” choice. A pilot study illustrates the details of the proposed method.
The DMs were a group of graduate students from the University of Paderborn in Germany. The pilot study concerned the addition
of new members into the European Union (EU), a decision that has profound economic and political effects on both the entering
and existing members of the Union. The DMs were required to consider a large number of internal strengths and weaknesses and
external opportunities and threats in assessing the decision to enlarge the EU. Although the pilot study was not performed
by actual DMs from the EU, it was an excellent platform for testing the proposed model. 相似文献
10.