Spin-Transfer and Exchange Torques in Ferromagnetic Superconductors

We consider how superconducting correlations influence spin-transfer torques in ferromagnetic superconductors. It is demonstrated that there is a novel torque arising from particle-hole interference that depends on the U(1) phase associated with the superconducting order parameter. We also show that there is an equilibrium exchange torque between two ferromagnetic superconductors in contact via a normal metal mediated by Andreev states. The latter equilibrium magnetic torque is also sensitive to spin-resolved phase differences in the superconducting order parameters as well as to an externally applied phase difference.Comment: 5 pages, 3 figures. Accepted for publication in PR

Formulation and testing of biodegradable polymeric coating on zinc wires in cardiovascular stent application

Biodegradable and biocompatible poly (L-lactic-acid) (PLLA) coating was applied on a modified zinc (Zn) substrate by dip coating, with the intent to delay the bio-corrosion and slow the degradation rate of zinc substrate. 3-(Trimethoxysilyl) propyl methacrylate (MPS) was used for modification of the zinc substrate for promoting the adhesion between the metallic substrate and the polymer coating. It is hypothesized that the delay in Zn biodegradation could be useful in the first several weeks to prevent the early loss of mechanical integrity of the endovascular stent and to improve the healing process of the diseased vascular site. The PLLA coating was used in this study because of its biodegradability, favorable degradation rate, hydrophobicity and favorable mechanical properties. Static immersion, electrochemical and inductively coupled plasma (ICP) tests were used to investigate the degradation behavior of a polymer coated modified Zn substrate. Two uniform polymer layers with thickness of 1 and 3 µm were coated on the Zn substrate. The potentiodynamic polarization test indicated that the 1 µm polymer coated specimen has higher corrosion potentials (Ecorr) and lower corrosion cur rents (icorr) in the simulated body fluid (SBF) compared to the uncoated Zn. AC impedance measurement in EIS test also demonstrated a significant improvement in the impedance and polarization resistance of the coated Zn substrate. However, after 10 days of immersion in the SBF, the impedance reduced drastically which is indicative of a coating degradation and penetration of the electrolyte to the zinc substrate. Immersion degradation studies showed that the cross-sectional area (CSA) reduction and penetration rate (PR) for polymer coated samples are 5 times smaller than for uncoated samples after 14 days of immersion in SBF solution. Results of the ICP method indicated an increase in the release of the Zn2+ to the solution for the uncoated Zn, while the 1 µm PLLA coated sample demonstrated much slower release rate of Zn2+ and the concentration of Zn ion during the 14 days’ immersion in SBF was almost the same. In in vivo studies, the polymer-coated Zn and uncoated Zn samples were implanted into the abdominal aorta of the rats and then directed into the lumen. The explants were extracted after 0.5 to 6 months. The results of in vivo study indicated that the uncoated samples have approximately two times higher CSA reduction and PR in comparison to the coated samples during first 4.5 months. After 4.5 months, the CSA reduction and PR increased significantly. However, the histological analysis of the biological tissue surrounding samples showed a reduction in biocompatibility of the polymer coated samples indicated by increasing cell toxicity and neointimal hyperplasia

Moving Femininities: Queer Critique and Transnational Arab Culture.

Moving Femininities focuses on three diverse and eminent figures of Arab femininity: the Golden Era Egyptian belly dancer Samia Gamal (1924-1994), the pan-Arab storyteller of The Thousand and One Nights, Scheherazade, and the Palestinian revolutionary Leila Khaled (b. 1944). By examining Arab and Arab American representations of each figure, my research demonstrates how Arab femininity is repurposed and remade by Arab and Arab American writers and artists struggling to represent Arab cultures against racism and Orientalism, all while remaining “authentically” Arab. I perform close readings of Gamal, Scheherazade, and Khaled in film, literature, and visual culture respectively; archival research, conducted in Egypt, Palestine, and the US provide cultural and historical context for my analysis. The project reveals how colonial logics limit the representations of femininity and produce a normative, narrow vision of Arab sexuality. My analysis reveals how Arab responses to colonialism and Orientalism have informed the representation of sexual and gendered norms; by destabilizing the representations of gender, sexuality, and race in these figures, I am able to locate subversive performances of gender and sexuality across their texts. As such, my work is a feminist and queer of color intervention in the scholarship on and representations of Arab gender and sexuality. Moreover, this dissertation examines how nations of origin affect those in the diaspora and how those in diaspora inform the home culture. Moving Femininities thus traces the movement of Arab cultures across national lines, the political movements enabled by attention to and regulation of femininity, and the new movements we might imagine for our queer Arab futures.PhDAmerican CultureUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/111527/1/mejdules_1.pd

Efficient Synthesis of α-Oximinoketones using Carboxyl and Nitrite Functionalized Graphene Quantum Dots: Dual role of Nanostructure as a Catalyst and Reagent

Carboxyl and nitrite functionalized graphene quantum dots (CNGQDs) was used for the efficient synthesis of α-oximinoketones under free mineral acid conditions at room temperature. CNGQDs was prepared via o-nitrozation of carboxyl and hydroxyl graphene quantum dots (CHGQDs) and used as a nitrosonium source and also as an efficient acidic catalyst for the synthesis of α-oximinoketones. The structure of the catalyst was characterized by FT-IR, XRD, TGA and photoluminescence techniques. The structures of the synthesized products were confirmed by FT-IR, 1H-NMR and 13C-NMR spectroscopic techniques. Stability and recyclability of the prepared homogeneous catalyst was studied in details. Reaction times and yields of the products were compared with previous reported methods resulting high yields and also shorter reaction times