Incompressible Navier-Stokes Solutions for Vortical flows over slender body at High Incidence

Ashraf A. Omar,노오현 한국항공우주학회 1997 한국항공우주학회 학술발표회 논문집 Vol.- No.-

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>

Video multicast cooperative communication in 5G systems with radio frequency energy harvesting

Ashraf, Mateen,Jang, Ju Wook,Han, Jong-Ki,Lee, Kyung-Geun Elsevier 2018 Journal of Computer Communications Vol.118 No.-

<P><B>Abstract</B></P> <P>In this paper, the performance of radio frequency energy harvesting cooperative multicast communication is analyzed in terms of outage probability. The multicast communication between base station (BS) and multiple destinations is assisted by one energy harvesting relay chosen from multiple energy harvesting relays. The relays harvest energy from the BS transmissions to be able to transmit for cooperation. We propose two power splitting approaches at the relays for energy harvesting. The first approach splits the received signal at the relays into two portions and send them to decoding/energy harvesting circuitry, simultaneously. In the second approach, the received signal during any receiving time is either sent to the information decoding circuitry or energy harvesting circuitry depending on the strength of the received signal. Analytical expressions of outage probability for these two power splitting approaches are derived. The derived expressions are validated by comparing them with the simulation results. Further, the outage probability of our proposed energy harvesting cooperative multicast system is almost equal to the non-energy harvesting cooperative multicast system.</P>

Smart Energy Efficient Device-to-Multidevice Cooperative Clustering for Multicasting Content

Ashraf, Mateen,Yeo, Woon-Young,Woo, Miae,Lee, Kyung-Geun Taylor & Francis 2016 INTERNATIONAL JOURNAL OF DISTRIBUTED SENSOR NETWOR Vol.2016 No.-

Nine months versus 12 months of adjuvant trastuzumab for patients with HER2-positive breast cancer

Ashraf Mahmoud El-Enbaby,Nadia Ahmed Abd El Moneim,Gehan Abd El atti Khedr,Yasmine Mohamed Nagy Elwany 대한종양외과학회 2018 Korean Journal of Clinical Oncology Vol.14 No.2

Purpose: This study aimed to compare the results of treatment with adjuvant trastuzumab for 9 months versus 12 months in human epider�mal growth factor 2 (HER2)-positive breast cancer patients. The primary endpoint was disease-free survival. Secondary endpoints included cardiac safety, tolerability, and overall survival. Methods: The study included 60 non-metastatic HER2-positive breast cancer patients. All study patients underwent surgery, received adju�vant chemotherapy, radiotherapy and hormonal therapy if indicated. Thirty patients were randomized in each group. Group I patients received adjuvant trastuzumab for 12 months, while group II patients received adjuvant trastuzumab for 9 months. Patients were assessed by clinical examination and Echocardiography during treatment. Results: After median follow-up of 12 months, 90% of the patients in group I were disease free and 83.3% of patients in group II were dis�ease free (P=0.402). All studied population in both groups I and II were alive at the end of the 1-year follow-up period after the completion of adjuvant trastuzumab treatment thus overall survival is 100%. Conclusion: Trastuzumab is tolerable and its side effects are reversible. Nine months of adjuvant trastuzumab treatment is more cost effec�tive than the standard 12 months.

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>

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>

Analysis of composite frame structures with mixed elements – state of the art

Ashraf Ayoub 국제구조공학회 2012 Structural Engineering and Mechanics, An Int'l Jou Vol.41 No.2

The paper presents a review of the application of the newly proposed mixed finite element model for seismic simulation of different types of composite frame structures. To evaluate the performance of the element, a comparison with displacement-based and force-based models is conducted. The study revealed that the mixed model is superior to the others in terms of both speed of convergence and numerical stability, and is therefore considered the most practical approach for modeling of composite structures. In this model, the element is derived using independent force and displacement shape functions. The nonlinear response of the frame element is based on the section discretization into fibers with uniaxial material models. The interfacial behavior is modeled using an inelastic interface element. Numerical examples to clarify the advantages of the model are presented for the following structural applications: anchored reinforcing bar problems, composite steel-concrete girders with deformable shear connectors, beam on elastic foundation elements, R/C girders strengthened with FRP sheets, R/C beam-columns with bond-slip, and prestressed concrete girders. These studies confirmed that the model represents a major advancement over existing elements in simulating the inelastic behavior of composite structures.

The effect of two temperatures on a FG nanobeam induced by a sinusoidal pulse heating

Ashraf M. Zenkour,Ahmed E. Abouelregal 국제구조공학회 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.51 No.2

The present investigation is concerned with the effect of two temperatures on functionally graded (FG) nanobeams subjected to sinusoidal pulse heating sources. Material properties of the nanobeam are assumed to be graded in the thickness direction according to a novel exponential distribution law in terms of the volume fractions of the metal and ceramic constituents. The upper surface of the FG nanobeam is fully ceramic whereas the lower surface is fully metal. The generalized two-temperature nonlocal theoryof thermoelasticity in the context of Lord and Shulman's (LS) model is used to solve this problem. The governing equations are solved in the Laplace transformation domain. The inversion of the Laplace transformation is computed numerically using a method based on Fourier series expansion technique. Somecomparisons have been shown to estimate the effects of the nonlocal parameter, the temperature discrepancy and the pulse width of the sinusoidal pulse. Additional results across the thickness of the nanobeam are presented graphically.

Thermoelastic interaction in functionally graded nanobeams subjected to time-dependent heat flux

Ashraf M. Zenkour,Ahmed E. Abouelregal 국제구조공학회 2015 Steel and Composite Structures, An International J Vol.18 No.4

This paper investigates the vibration phenomenon of a nanobeam subjected to a time-dependent heat flux. Material properties of the nanobeam are assumed to be graded in the thickness direction according to a novel exponential distribution law in terms of the volume fractions of the metal and ceramic constituents. The upper surface of the functionally graded (FG) nanobeam is pure ceramic whereas the lower surface is pure metal. A nonlocal generalized thermoelasticity theory with dual-phase-lag (DPL) model is used to solve this problem. The theories of coupled thermoelasticity, generalized thermoelasticity with one relaxation time, and without energy dissipation can extracted as limited and special cases of the present model. An analytical technique based on Laplace transform is used to calculate the variation of deflection and temperature. The inverse of Laplace transforms are computed numerically using Fourier expansion techniques. The effects of the phase-lags (PLs), nonlocal parameter and the angular frequency of oscillation of the heat flux on the lateral vibration, the temperature, and the axial displacement of the nanobeam are studied.