Capacity Maximizing Adaptive Power Splitting Protocol for Cooperative Energy Harvesting Communication Systems

Ashraf, Mateen,Jang, Ju-Wook,Han, Jong-Ki,Lee, Kyung Geun IEEE 2018 IEEE COMMUNICATIONS LETTERS Vol.22 No.5

<P>In this letter, we propose a novel power splitting (PS) protocol for energy harvesting cooperative communication systems. In our proposed system, the relay harvests energy from the source transmissions, by employing adaptive PS protocol, for powering the retransmissions to the destination. Unlike existing PS protocols, which are not optimal in terms of capacity maximization, our proposed adaptive PS protocol maximizes the achievable capacity between the source and destination. Furthermore, we present analytical expressions for the outage probability and average achievable capacity. Simulation results validate the analytical expressions and show that the achievable capacity for the proposed PS protocol is better than the existing PS protocol.</P>

Regulation of senescence associated signaling mechanisms in chondrocytes for cartilage tissue regeneration

Ashraf, S.,Cha, B.H.,Kim, J.S.,Ahn, J.,Han, I.,Park, H.,Lee, S.H. Published for the Society by Baillère Tinda 2016 OSTEOARTHRITIS AND CARTILAGE Vol.24 No.2

<P>Adult articular chondrocytes undergo slow senescence and dedifferentiation during in vitro expansion, restricting successful cartilage regeneration. A complete understanding of the molecular signaling pathways involved in the senescence and dedifferentiation of chondrocytes is essential in order to better characterize chondrocytes for cartilage tissue engineering applications. During expansion, cell fate is determined by the change in expression of various genes in response to aspects of the microenvironment, including oxidative stress, mechanical stress, and unsuitable culture conditions. Rapid senescence or dedifferentiation not only results in the loss of the chondrocytic phenotype but also enhances production of inflammatory mediators and matrix-degrading enzymes. This review focuses on the two groups of genes that play direct and indirect roles in the induction of senescence and dedifferentiation. Numerous degenerative signaling pathways associated with these genes have been reported. Upregulation of the genes interleukin 1 beta (IL-1 beta), p53, p16, p21, and p38 mitogen-activated protein kinase (MAPK) is responsible for the direct induction of senescence, whereas downregulation of the genes transforming growth factor-beta (TGF-beta), bone morphogenetic protein-2 (BMP-2), SRY (sex determining region Y)-box 9 (SOX9), and insulin-like growth factor-1 (IGF-1), indirectly induces senescence. In senescent and dedifferentiated chondrocytes, it was found that TGF-beta, BMP-2, SOX9, and IGF-1 are downregulated, while the levels of IL-1 beta, p53, p16, p21, and p38 MAPK are upregulated followed by inhibition of the normal molecular functioning of the chondrocytes. This review helps to elucidate the underlying mechanism in degenerative cartilage disease, which may help to improve cartilage tissue regeneration techniques. (C) 2015 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.</P>

Benzylamides from Salvadora persica

Ashraf Taha Khalil 대한약학회 2006 Archives of Pharmacal Research Vol.29 No.11

A phytochemical investigation of stems from Salvadora persica resulted in the first isolation of four benzylamides from a natural source. The isolated compounds were identified as butanediamide, N1,N4-bis(phenylmethyl)-2(S)-hydroxy-butanediamide (1), N-benzyl-2-phenylacetamide (2), N-benzylbenzamide (3) and benzylurea (4). The structure elucidation was accomplished using spectroscopic methods, especially 2D NMR and HREIMS. Compound 2 revealed a significant inhibitory effect on human collagen-induced platelet aggregation, and a moderate antibacterial activity against Escherichia coli.

Numerical Simulation of the Interaction between Slender Body Vortices and a Vertical Fin

Ashraf A. Omar,김종암,노오현 한국항공우주학회 1998 한국항공우주학회 학술발표회 논문집 Vol.- No.-

Flurbiprofen–antioxidant mutual prodrugs as safer nonsteroidal anti-inflammatory drugs: synthesis, pharmacological investigation, and computational molecular modeling

Ashraf, Zaman,Alamgeer,Kanwal, Munazza,Hassan, Mubashir,Abdullah, Sahar,Waheed, Mamuna,Ahsan, Haseeb,Kim, Song Ja Dove Medical Press 2016 Drug design, development and therapy Vol.10 No.-

<P>Flurbiprofen–antioxidant mutual prodrugs were synthesized to reduce the gastrointestinal (GI) effects associated with flurbiprofen. For reducing the GI toxicity, the free carboxylic group (–COOH) was temporarily masked by esterification with phenolic –OH of natural antioxidants vanillin, thymol, umbelliferone, and sesamol. The in vitro hydrolysis of synthesized prodrugs showed that they were stable in buffer solution at pH 1.2, indicating their stability in the stomach. The synthesized prodrugs undergo significant hydrolysis in 80% human plasma and thus release free flurbiprofen. The minimum reversion was observed at pH 1.2, suggesting that prodrugs are less irritating to the stomach than flurbiprofen. The anti-inflammatory, analgesic, antipyretic, and ulcerogenic activities of prodrugs were evaluated. All the synthesized prodrugs significantly (<I>P</I><0.001) reduced the inflammation against carrageenan and egg albumin-induced paw edema at 4 hours of study. The reduction in the size of the inflamed paw showed that most of the compounds inhibited the later phase of inflammation. The prodrug 2-oxo-2<I>H</I>-chromen-7-yl-2-(2-fluorobiphenyl-4-yl)propanoate (<B>4b</B>) showed significant reduction in paw licking with percentage inhibition of 58%. It also exhibited higher analgesic activity, reducing the number of writhes with a percentage of 75%, whereas flurbiprofen showed 69% inhibition. Antipyretic activity was investigated using brewer’s yeast-induced pyrexia model, and significant (<I>P</I><0.001) reduction in rectal temperature was shown by all prodrugs at all times of assessment. The results of ulcerogenic activity showed that all prodrugs produced less GI irritation than flurbiprofen. Molecular docking and simulation studies were carried out with cyclooxygenase (COX-1 and COX-2) proteins, and it was observed that our prodrugs have more potential to selectively bind to COX-2 than to COX-1. It is concluded that the synthesized prodrugs have promising pharmacological activities with reduced GI adverse effects than the parent drug.</P>

Synthesis, Bioevaluation and Molecular Dynamic Simulation Studies of Dexibuprofen–Antioxidant Mutual Prodrugs

Ashraf, Zaman,Alamgeer,,Rasool, Raqiqatur,Hassan, Mubashir,Ahsan, Haseeb,Afzal, Samina,Afzal, Khurram,Cho, Hongsik,Kim, Song Ja,Zhang, Ge,Lu, Aiping MDPI 2016 INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES Vol.17 No.12

<P>Dexibuprofen–antioxidant conjugates were synthesized with the aim to reduce its gastrointestinal effects. The esters analogs of dexibuprofen <B>5a</B>–<B>c</B> were obtained by reacting its –COOH group with chloroacetyl derivatives <B>3a</B>–<B>c</B>. The in vitro hydrolysis data confirmed that synthesized prodrugs <B>5a</B>–<B>c</B> were stable in stomach while undergo significant hydrolysis in 80% human plasma and thus release free dexibuprofen. The minimum reversion was observed at pH 1.2 suggesting that prodrugs are less irritating to stomach than dexibuprofen. The anti-inflammatory activity of <B>5c</B> (<I>p</I> < 0.001) is more significant than the parent dexibuprofen. The prodrug <B>5c</B> produced maximum inhibition (42.06%) of paw-edema against egg-albumin induced inflammation in mice. Anti-pyretic effects in mice indicated that prodrugs <B>5a</B> and <B>5b</B> showed significant inhibition of pyrexia (<I>p</I> < 0.001). The analgesic activity of <B>5a</B> is more pronounced compared to other synthesized prodrugs. The mean percent inhibition indicated that the prodrug <B>5a</B> was more active in decreasing the number of writhes induced by acetic acid than standard dexibuprofen. The ulcerogenic activity results assured that synthesized prodrugs produce less gastrointestinal adverse effects than dexibuprofen. The ex vivo antiplatelet aggregation activity results also confirmed that synthesized prodrugs are less irritant to gastrointestinal mucosa than the parent dexibuprofen. Molecular docking analysis showed that the prodrugs <B>5a</B>–<B>c</B> interacts with the residues present in active binding sites of target protein. The stability of drug–target complexes is verified by molecular dynamic simulation study. It exhibited that synthesized prodrugs formed stable complexes with the COX-2 protein thus support our wet lab results. It is therefore concluded that the synthesized prodrugs have promising pharmacological activities with reduced gastrointestinal adverse effects than the parent drug.</P>

Anticancer activities of some newly synthesized pyrazole and pyrimidine derivatives

Ashraf M. Mohamed,Weal A. El-Sayed,Musaed A. Alsharari,Husam R. M. Al-Qalawi,Mousa O. Germoush 대한약학회 2013 Archives of Pharmacal Research Vol.36 No.9

A series of pyrazolopyridine and pyridopyrimidinederivatives 2–6 were newly synthesized using3,5-bisarylmethylene-1-methylpiperidone as the startingmaterial. The anticancer activities of the synthesizedcompounds were evaluated using 59 different human tumorcell lines, representing cancers of CNS, ovary, renal,breast, colon, lung, leukemia, and melanoma, prostate aswell as kidney. Some of the tested compounds, especiallythose with a fluorine substituent at the para-position in thephenyl ring and those with a pyridopyrimidine-2-thionewith a free –NH or –SH, exhibited greater in vitro antitumoractivities at low concentrations (log 10 [GI50] =-4.6) against the human tumor cell lines. Additionally,some of the compounds had moderate inhibitory effects onthe growth of the cancer cell lines. The detailed synthesis,spectroscopic data and antitumor properties of the synthesizedcompounds are reported.

Characterization of the Heavy Metals Contaminating the River Nile at El-Giza Governorate, Egypt and Their Relative Bioaccumulations in Tilapia nilotica

Ashraf M. Morgan,Ho-Chul Shin,A.M. Abd El Aty 한국독성학회 2008 Toxicological Research Vol.24 No.4

This study was carried out to measure the concentration of heavy metals (Pb, Mn, Cr, Cd, Ni, Zn, and Cu) in water and Bolti fish (Tilapia nilotica) samples collected from Rasheed branch of River Nile, north of El-Giza Governorate, Egypt by atomic absorption spectrophotometry. The investigated districts through which the branch passes include El-Manashi, Gezzaya, El Katta, Abo Ghaleb and Wardan. Based on WHO and FAO safety reference standards, the results of the current study showed that water and fish tissues were found to contain heavy metals at significantly variable concentration levels among the investigated districts. They were polluted with respect to all the metals tested at Gezzaya district. However, the levels of analyzed metals in water and fish tissues were found lower than legal limits in other districts. The heavy metals showed differential bioaccumulation in fish tissues of the different districts as the accumulation pattern (as total heavy metal residues) was district dependant as follow: Gezzaya >Wardan > El Katta > Abo Ghaleb > El Manashi.

Energy Efficient Online Power Allocation for Two Users With Energy Harvesting

Ashraf, Mateen,Jung, Jaehoon,Shin, Hun Min,Lee, Inkyu IEEE 2019 IEEE signal processing letters Vol.26 No.1

<P>In this letter, we propose an online power allocation (PA) method to maximize energy efficiency (EE) in energy harvesting systems with realistic battery constraints for two receivers. The optimization problem in this system configuration is challenging since it has a non-convex fractional form and the information of channel quality and the harvested energy can only be obtained causally in practice. To overcome these issues, we design time-average EE maximization through Lyapunov optimization techniques where the transmission power is computed with current battery information and channel fading. Moreover, based on random matrix theory, we present a simplified online EE algorithm. Numerical experiments verify that the proposed PA outperforms conventional online approaches with much reduced computational complexity.</P>

Foreign Investment in EGYPT

Ashraf Nadoury 한국법학원 1987 저스티스 Vol.20 No.-