Synthesis and cytotoxic activity of certain trisubstituted azetidin- 2-one derivatives as a cis-restricted combretastatin A-4 analogues

Salwa Elmeligie,Azza T. Taher,Nadia A. Khalil,Ahmed H. El-said 대한약학회 2017 Archives of Pharmacal Research Vol.40 No.1

Novel series of 1,3,4-trisubstituted azetidin-2-one derivatives 8a–p were synthesized and proposed ascytotoxic agents acting via inhibition of tubulin at thecolchicine binding site. The design of the target compoundswas based upon modification in the structure of the vasculartargeting agent combretastatin A-4 (CA-4). The cisdouble bond linker in CA-4 was replaced with the azetidin-2-one ring aiming to prevent the cis/trans isomerizationthat suppresses the activity of CA-4, thereby enhancing itsantiproliferative activity. All new compounds were investigatedin vitro against MCF-7 and HCT-116 cell lines. Theinhibition of tubulin polymerization by four most potentcompounds 8g, 8j, 8n and 8o was also evaluated. Thesynthesis of the final targets was achieved adopting Staudingerreaction. Molecular modeling studies were performedto rationalize the biological results.

Heat transfer characteristics and entropy generation for wing-shaped-tubes with longitudinal external fins in cross-flow

Sayed Ahmed E. Sayed Ahmed,Osama M. Mesalhy,Mohamed A. Abdelatief 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.6

A numerical study is conducted to clarify heat transfer characteristics, effectiveness and entropy generation for a bundle of wingshaped-tubes attached to Longitudinal fins (LF) at downstream side. The air-side Re a ranged from 1.8 x 10 3 to 9.7 x 10 3 . The fin height (h f ) and fin thickness (δ) have been changed as: (2 mm ≤ h f ≤ 12 mm) and (1.5 mm ≤ δ ≤ 3.5 mm). The analysis of entropy generation is based on the principle of minimizing the rate of total entropy generation that includes the generation of entropy due to heat transfer and friction losses. The temperature field around the wing-shaped-tubes with (LF) is predicted using commercial CFD FLUENT 6.3.26 software package. Correlations of Nu a , St a , and Bejan number (Be), as well as the irreversibility distribution ratio (Φ) in terms of Re a and design parameters for the studied bundle are presented. Results indicated that, installing fins with heights from 2 to 12 mm results in an increase in Nu a from 11 to 36% comparing with that of wing-shaped tubes without fins (NOF). The highest and lowest values of effectiveness (ε) at every value of the considered Re a range are occurred at h f = 6 mm and (NOF), respectively. The wing-shaped-tubes heat exchanger with h f = 6 mm has the highest values of (ε), efficiency index (η) and area goodness factor (G a ) and also the lowest values of Φ and hence the best performance comparing with other arrangements. The minimum values of Φ are occurred at h f = 6 mm. (Be) decreases with increasing Re a for all studied h f . The heat transfer irreversibility predominates for (1800 ≤ Re a ≤ 4200) while the opposite is true for (6950 < Re a ≤ 9700). δ has negligible effect on Nu a and heat transfer irreversibility. Comparisons between the experimental and numerical results of the present study and those, previously, obtained for similar available studies showed good agreements.

Quercetin Confers Tumoricidal Activity Through Multipathway Mechanisms in A N-Methylnitrosourea Rat Model of Colon Cancer

Ahmed, Hanaa H,Aglan, Hadeer A,Zaazaa, Asmaa M,Shalby, Aziza B,Toumy, Sayed A El Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.11

Objective: This research was conducted to explore mechanisms behind the potency of quercetin in inhibiting colon cancer induced in an experimental model. Materials and Methods: Forty adult male rats of Wistar strain were distributed into 4 groups; a negative control group, a colon cancer bearing group, a quercetin-treated group and a 5-fluorouracil (5-FU)-treated group. Serum TAG72 and GAL3 levels were quantified by ELISA. Colonic Wnt5a and Axin-1 gene expression was estimated by PCR. In addition, colonic tissues were subjected to immunohistochemical examination of Bax expression and histological investigation of histopathological alterations. Results: Quercetin elicited significant reduction in serum TAG72 and GAL3 levels, in addition to significant suppression of colonic Wnt5a gene expression and amplification of colonic Axin-1 gene expression. Also, it caused moderate positive reaction for Bax in mucosal epithelium. Conclusion: The present research provides experimental evidence about the activity of quercetin in the colon cancer of rats. Inhibitory effects on cancer development might be ascribable to regulatory action on Wnt signaling and induction of apoptosis.

Control of Open-Loop PWM Delta-Connected Motor-Drive Systems under One Phase Failure Condition

Sayed-Ahmed, Ahmed,Demerdash, Nabeel A.O. The Korean Institute of Power Electronics 2011 JOURNAL OF POWER ELECTRONICS Vol.11 No.6

A new fault-tolerant control topology for open-loop motor-drive systems with Delta-connected stator windings is introduced in this paper. This new control topology enables the operation of a three-phase induction machine as a two-phase machine fed by a three-phase inverter upon a failure in one of the motor phases. This topology utilizes the "open-Delta" configuration to independently control the current in each of the two remaining healthy phases. This new control technique leads to the alleviation of any torque pulsations resulting from the consequences of the asymmetrical conditions associated with this class of faults.

Control of Open-Loop PWM Delta-Connected Motor-Drive Systems under One Phase Failure Condition

Ahmed Sayed-Ahmed,Nabeel A. O. Demerdash 전력전자학회 2011 JOURNAL OF POWER ELECTRONICS Vol.11 No.6

A new fault-tolerant control topology for open-loop motor-drive systems with Delta-connected stator windings is introduced in this paper. This new control topology enables the operation of a three-phase induction machine as a two-phase machine fed by a three-phase inverter upon a failure in one of the motor phases. This topology utilizes the “open-Delta” configuration to independently control the current in each of the two remaining healthy phases. This new control technique leads to the alleviation of any torque pulsations resulting from the consequences of the asymmetrical conditions associated with this class of faults.

Life Span Extension of Caenorhabditis elegans by Novel Pyridoperimidine Derivative

Ahmed A. R. Sayed,Kamal M. El-Shaieb,Aboul-Fetouh E. Mourad 대한약학회 2012 Archives of Pharmacal Research Vol.35 No.1

Zwitterions formed from the addition of triphenylphosphine to dialky acetylene-dicarboxylates attack the nucleus of both 1H-perimidine (1) and 1H-benzo[d]imidazole (9) to form novel pyrido[1,2,3-cd]perimidine and imidazo[4,5,1-ij]quinoline derivatives in moderate yields (64-72%). The biological activity of the products has been studied. Compound 3a was found to extend life span of wild type Caenorhabditis elegans under standard laboratory conditions. Both heat stress and induced chemical stress resistance of wild type C. elegans were improved in a reverse dose-dependent manner due to 3a treatment. In addition, treatment of worms with compound 3a significantly attenuated the formation of advanced glycation end products in a reverse dose-dependent manner.

Synergistic activity of Bacillus thuringiensis δ‐endotoxin and TMOF against Culex pipiens and Spodoptera littoralis larvae

Ahmed M.A. Mohammed,Mervat R. DIAB,Sayed M.S. KHALIL 한국곤충학회 2018 Entomological Research Vol.48 No.3

Trypsin Modulating Oostatic Factor (TMOF) is a decapeptide hormone that inhibits the biosynthesis of digestive enzymes in the mosquito midgut. The hormone inhibits food digestion and ultimately leads to starvation and death. It has been used as a biological insecticide to control mosquitoes. In an attempt to increase the insecticidal activity of TMOF, a combination of CryIC (δ‐endotoxin from Bacillus thuringiensis) and TMOF was determined. Eight recombinant proteins fused with GST (glutathione‐S‐transferase) were expressed in Escherichia coli cells. Their insecticidal activities were determined against Culex pipiens and Spodoptera littoralis larvae. Purified GST‐TMOF and its analogue GST‐YDPAS exhibited a moderate toxicity on C. pipiens larvae with LC50 of 145.9 and 339.9 μg/mL, respectively. Unexpectedly, no mortality was observed in first instar larvae of S. littoralis. Puirified GST‐TMOF and GST‐YDPAS together with Bt toxin showed a synergistic toxic effect on both Culex and Spodoptera larvae. In the presence of 100 μg/mL GST‐TMOF and GST‐YDPAS, the median lethal concentration of entomocidus on culex larvae decreased from 52.1 to 16.7 and 31.9 μg/mL, respectively. Likewise, GST‐TMOF and GST‐YDPAS incorporated with 0.07 μg/cm2 of enotmocidus showed insecticidal activity against S. littoralis with LC50 of 16.4 and 21.9 μg/cm2. The E. coli lysates containing GST‐CryIC and its 3′‐truncated version showed low toxicity against the lepidopteran insect (10.8 and 16.6 μg/cm2) compared to 0.15 μg/cm2 of the native crystalline form of CryIC. Similarly, the mosquitocidal activity of the recombinant Bt toxins was low.

Removal of Reactive Blue 19 dye from Aqueous Solution Using Natural and Modified Orange Peel

Sohair A. Sayed Ahmed,Laila B. Khalil,Thoria El-Nabarawy 한국탄소학회 2012 Carbon Letters Vol.13 No.4

Orange peel (OP) exhibits a sorption capacity towards anionic dyes such as reactive blue 19 (RB19). Cetyltrimethylammonium bromide (CTAB) as a cationic surfactant was used to modify the surface nature of OP to enhance its adsorption capacity for anionic dyes from an aqueous solution. Four adsorbents were investigated: the OP, sodium hydroxide-treated OP (SOP), CTAB-modified OP and CTAB-modified SOP. The physical and chemical properties of these sorbents were determined using nitrogen adsorption at 77 K and by scanning electron microscope and Fourier transform infrared spectroscopy techniques. The adsorption of the RB19 dye was assessed with these sorbents at different solution pH levels and temperatures. The effect of the contact time was considered to determine the order and rate constants of the adsorption process. The adsorption data were analyzed considering the Freundlich, Langmuir, Elovich and Tempkin models. The adsorption of RB19 by the assessed sorbents is of the chemisorption type following pseudo-first-order kinetics. CTAB modification brought about a significant increase in RB19 adsorption, which was ascribed to the grafting of the sorbent with a cationic surfactant.

Adsorption properties of activated carbon prepared from pre-carbonized petroleum coke in the removal of organic pollutants from aqueous solution

S.A. Sayed Ahmed,Reham M.M. Abo El-Enin,Th. El-Nabarawy 한국탄소학회 2011 Carbon Letters Vol.12 No.3

Activated carbon was prepared from pre-carbonized petroleum coke. Textural properties were determined from studies of the adsorption of nitrogen at 77 K and the surface chemistry was obtained using the Fourier-transform infrared spectrometer technique and the Boehm titration process. The adsorption of three aromatic compounds, namely phenol (P), p-nitrophenol (PNP) and benzoic acid (BA) onto APC in aqueous solution was studied in a batch system with respect to contact time, pH, initial concentration of solutes and temperature. Active carbon APC obtained was found to possess a high surface area and a predominantly microporous structure; it also had an acidic surface character. The experimental data fitted the pseudo-second-order kinetic model well; also, the intraparticle diffusion was the only controlling process in determining the adsorption of the three pollutants investigated. The adsorption data fit well with the Langmuir and Freundlich models. The uptake of the three pollutants was found to be strongly dependent on the pH value and the temperature of the solution. Most of the experiments were conducted at pH 7; the pH(PZC) of the active carbon under study was 5.0; the surface of the active carbon was negatively charged. The thermodynamic parameters evaluated for APC revealed that the adsorption of P was spontaneous and exothermic in nature, while PNP and BA showed no-spontaneity of the adsorption process and that process was endothermic in nature.

Comparative Study of Itraconazole-Cyclodextrin Inclusion Complex and Its Commercial Product

Ibrahim A. Alsarra,Fars K. Alanazi,Sayed M. Ahmed,Ahmed A. Bosela,Suliman S. Alhamed,Hammam A. Mowafy,Steven H. Neau 대한약학회 2010 Archives of Pharmacal Research Vol.33 No.7

Itraconazole (ITZ) solid complex using hydroxypropyl-β-cyclodextrin (ITZ-HP-β-CD) with 20% polyvinylpyrrolidone was prepared by a co-evaporation method. The complex improved antifungal activity against C. parapasilosis and C. albicans. The complex demonstrated good flow and compressibility characteristics. The complex was formulated as a capsule dosage form and drug release was evaluated. Capsules containing ITZ-HP-β-CD at a molar ratio of 1:3 with 20% polyvinylpyrrolidone have a faster dissolution rate than commercial capsules (Sporanox ®). About 88% of ITZ was released in less than 30 min and the initial dissolution rate exhibited a 3.5-fold increase compared to the commercial product. UV spectrophotometeric, HPLC, and antimicrobial methods were used to determine ITZ concentration in the release medium and the results obtained by these methods are reported. It was found that HPLC analysis is a suitable and reliable method for determination of the drug concentration with a coefficient of variation less than 10%. The intraday precision showed a coefficient of variation less than 3.96%, and that for interday was less than 4.99%. The HPLC method was more accurate and precise than the antimicrobial and UV-spectrophotometric methods for determination of ITZ concentration present in the release medium.