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排序方式: 共有259条查询结果,搜索用时 15 毫秒
81.
Amina M. G. Zedan Mohamed I. Sakran Omar Bahattab Yousef M. Hawsawi Osama Al-Amer Atif A. A. Oyouni Samah K. Nasr Eldeen Mohammed A. El-Magd 《Molecules (Basel, Switzerland)》2021,26(11)
The use of insects as a feasible and useful natural product resource is a novel and promising option in alternative medicine. Several components from insects and their larvae have been found to inhibit molecular pathways in different stages of cancer. This study aimed to analyze the effect of aqueous and alcoholic extracts of Vespa orientalis larvae on breast cancer MCF7 cells and investigate the underlying mechanisms. Our results showed that individual treatment with 5% aqueous or alcoholic larval extract inhibited MCF7 proliferation but had no cytotoxic effect on normal Vero cells. The anticancer effect was mediated through (1) induction of apoptosis, as indicated by increased expression of apoptotic genes (Bax, caspase3, and p53) and decreased expression of the anti-apoptotic gene Bcl2; (2) suppression of intracellular reactive oxygen species; (3) elevation of antioxidant enzymes (CAT, SOD, and GPx) and upregulation of the antioxidant regulator Nrf2 and its downstream target HO-1; (4) inhibition of migration as revealed by in vitro wound healing assay and downregulation of the migration-related gene MMP9 and upregulation of the anti-migratory gene TIMP1; and (5) downregulation of inflammation-related genes (NFκB and IL8). The aqueous extract exhibited the best anticancer effect with higher antioxidant activities but lower anti-inflammatory properties than the alcoholic extract. HPLC analysis revealed the presence of several flavonoids and phenolic compounds with highest concentrations for resveratrol and naringenin in aqueous extract and rosmarinic acid in alcoholic extract. This is the first report to explain the intracellular pathway by which flavonoids and phenolic compounds-rich extracts of Vespa orientalis larvae could induce MCF7 cell viability loss through the initiation of apoptosis, activation of antioxidants, and inhibition of migration and inflammation. Therefore, these extracts could be used as adjuvants for anticancer drugs and as antioxidant and anti-inflammatory agents. 相似文献
82.
The efficacy of five compounds of a biopolymer chitosan and Bio-fly (Beauveria bassiana fungus) as biopesticide was evaluated on Ceratitis capitata under laboratory conditions. The inhibitory effects on acetylcholinesterase (AChE) and adenosinetriphosphatase (ATPase) as biochemical indicators were also determined in vivo. The results indicated that B. bassiana based Bio-fly exhibited significant toxicity against C. capitata (LC50 = 3008 and 3126 mg/L after 48 h in females and males, respectively) followed by the derivatives of chitosan, N-(4-propylbenzyl)chitosan and N-(2-nitrobenzyl)chitosan. Bio-fly displayed remarkable inhibition of AChE activity (IC50 = 2220 mg/L) while N-(2-chloro,6-flourobenzyl)chitosan, N-(4-propylbenzyl)chitosan and N-(3,4-methylenedioxybenzyl) chitosan had no significant difference in inhibitory action. In adult males, N-(2-nitrobenzyl)chitosan exhibited the highest inhibitory action (IC50 = 6569 mg/L). In addition, the toxic effects of the tested compounds on the activity of ATPase indicated that highly significant inhibition was found with N-(4-propylbenzyl)chitosan with an IC50 of 8194 and 8035 mg/L, in females and males, respectively. 相似文献
83.
-5-Sulfono-7-(4-x phenyl azo)-8-hydroxy quinoline (SAHQ)-x ligands, x = NO2 or CH3 or Cl have polycrystalline structure in as synthesized condition. Thermally evaporated thin films of SAHQ-x have crystal structure depending on the substitution group; SAHQ-NO2 and SAHQ-Cl films have nano-crystalline structure with different degree of crystallinity and SAHQ-CH3 film has amorphous structure. The changes in optical functions and therefore optical constants with substitution group variation have been calculated by using spectrophotometer measurements of the transmittance and reflectance at nearly normal incidence of light in the wavelength range 200–2500 nm. Substitution group variation influences the refractive index, dispersion parameters, optical functions and bond length of SAHQ. It has no influence on mobility, relaxation time and plasma frequency of charge carriers. The obtained optical energy gaps for SAHQ-x ligands, x = NO2 or CH3 or Cl are 1.89, 2 and 2eV, respectively. 相似文献
84.
Masoud Nasr‐Esfahani Morteza Montazerozohori Safie Mehrizi 《Journal of heterocyclic chemistry》2011,48(2):249-254
A practical, efficient, and inexpensive method for the synthesis of 2‐imidazoline from the reaction of nitriles with ethylenediamine or 1,2‐propanediamine using p‐toluenesulfonic acid or pyridinium p‐toluenesulfonate under reflux conditions is reported. This catalyst can be successfully applied for the chemoselective conversion of dicyanobenzenes to corresponding mono‐ and bis‐imidazolines. The applications of these catalysts are feasible because of easy preparation, easy handling, stability, inexpensive, good activity, and eco‐friendly. J. Heterocyclic Chem., (2011). 相似文献
85.
Nasr G Guerlin A Dumur F Beouch L Dumas E Clavier G Miomandre F Goubard F Gigmes D Bertin D Wantz G Mayer CR 《Chemical communications (Cambridge, England)》2011,47(38):10698-10700
Two iridium(III) soft salts based on ion-paired dinuclear cationic and mononuclear anionic complexes were designed and investigated as phosphorescent emitters for solution processed OLEDs. New dinuclear cationic complexes were prepared with two different bridging ligands, a carbazole and a phenylene spacer. Best devices were designed with the soft salt bearing a carbazole moiety. 相似文献
86.
Mohy Eldin MS Seuror EI Nasr MA El-Aassar MR Tieama HA 《Applied biochemistry and biotechnology》2011,164(1):10-22
ρ-Benzoquinone-activated alginate beads were presented as a new carrier for affinity covalent immobilization of glucoamylase
enzyme. Evidences of alginate modification were extracted from FT-IR and thermal gravimetric analysis and supported by morphological
changes recognized through SEM examination. Factors affecting the modification process such as ρ-benzoquinone (PBQ) concentration,
reaction time, reaction temperature, reaction pH and finally alginate concentration, have been studied. Its influence on the
amount of coupled PBQ was consequently correlated to the changes of the catalytic activity and the retained activity of immobilized
enzyme, the main parameters judging the success of the immobilization process. The immobilized glucoamylase was found kept
almost 80% of its native activity giving proof of non-significant substrate, starch, diffusion limitation. The proposed affinity
covalent immobilizing technique would rank among the potential strategies for efficient immobilization of glucoamylase enzyme. 相似文献
87.
We propose to study a EOQ-type inventory model with unreliable supply, with each order containing a random proportion of defective items. Every time an order is received, an acceptance sampling plan is applied to the lot, according to which only a sample is inspected instead of the whole lot. If the sample conforms to the standards, i.e. if the number of imperfect items is below an “acceptance number”, no further screening is performed. Otherwise, the lot is subject to 100% screening. We formulate an integer non-linear mathematical program that integrates inventory and quality decisions into a unified profit model, to jointly determine the optimal lot size and optimal sampling plan, characterized by a sample size, and an acceptance number. The optimal decisions are determined in a way to achieve a certain average outgoing quality limit (AOQL), which is the highest proportion of defective items in the outgoing material sold to customers. We provide a counter-example demonstrating that the expected profit function, objective of the mathematical program, is not jointly concave in the lot and sample size. However, we show that for a given sampling plan, the expected profit function is concave in the lot size. A solution procedure is presented to compute the optimal solution. Numerical analysis is provided to gain managerial insights by analyzing the impact of changing various model parameters on the optimal solution. We also show numerically that the optimal profit determined using this model is significantly higher when compared to the optimal profit obtained using Salameh and Jaber (2000)’s [1] model, indicating much higher profits when acceptance sampling is used. 相似文献
88.
Ibrahim A Darwish Tanveer A Wani Nasr Y Khalil Abdul-Aziz Al-Shaikh Najm Al-Morshadi 《Chemistry Central journal》2012,6(1):1
A novel 96-microwell-based spectrophotometric assay has been developed and validated for determination of olmesartan medoxomil
(OLM) in tablets. The formation of a colored charge-transfer (CT) complex between OLM as a n-electron donor and 2, 5-dichloro-3,
6-dihydroxy-1, 4-benzoquinone (p-chloranilic acid, pCA) as a π-electron acceptor was investigated, for the first time, and
employed as a basis in the development of the proposed assay. The proposed assay was carried out in 96-microwell plates. The
absorbance of the colored-CT complex was measured at 490 nm by microwell-plate absorbance reader. The optimum conditions of
the reaction and the analytical procedures of the assay were established. Under the optimum conditions, linear relationship
with good correlation coefficient was found between the absorbance and the concentration of OLM in the range of 1-200 μg ml-1. The limits of detection and quantitation were 0.3 and 1 μg ml-1, respectively. No interference was observed from the additives that are present in the pharmaceutical formulation or from
hydrochlorothiazide and amlodipine that are co-formulated with OLM in some formulations. The assay was successfully applied
to the analysis of OLM in tablets with good accuracy and precision. The assay described herein has great practical value in
the routine analysis of OLM in quality control laboratories, as it has high throughput property, consumes minimum volume of
organic solvent thus it offers the reduction in the exposures of the analysts to the toxic effects of organic solvents, and
reduction in the analysis cost by 50-fold. Although the proposed assay was validated for OLM, however, the same methodology
could be used for any electron-donating analyte for which a CT reaction can be performed. 相似文献
89.
90.
B. Nasr Esfahani F. Ahmadi M. Ahmadi 《International Journal of Theoretical Physics》2009,48(7):1957-1964
Fidelity for the spin part of states of two spin-
particles is investigated from the viewpoint of moving observers. Using a numerical approach, the behavior of the fidelity
in terms of the boost parameter is described for different amounts of spin entanglement and momentum entanglement. It is shown
that for the spin entangled states the fidelity decreases less than that of the case of spin product states and there are
special cases for which the fidelity remains perfect regardless of moving observers’ velocity. Generally, in the limit of
boosts with speeds close to the speed of light, the fidelity saturates, i.e., it reaches to a constant value that depends
on the amount of momentum entanglement and the width of the momentum distribution function. 相似文献