Molecular characterization of salt stress in grapevine cultivars (Vitis vinifera L.) and rootstocks

Salt stress is an important factor inducing the expression of many genes; e.g. the osmotin gene is one of the very important genes responding to NaCl stress. After exposure to NaCl stress, the osmotin gene expression level was investigated in 6 grape cultivars grown in GAP (Southeast Anatolian region including the provinces Gaziantep, Şanliurfa, Diyarbakır, Mardin, Batman, Siirt and Şırnak) and in 4 grape cultivars and 7 rootstocks recommended to the GAP region. Expression levels were investigated by Northern blot analysis. The osmotin expression level was higher in scion cultivars than in rootstocks. Within grapevine cultivars, the highest osmotin gene expression level was observed in cv. Tahannebi, followed by Hönüsü, another GAP region cultivar. The osmotin gene expression levels of two grape cultivars, Ata sarisi and Alphonse Lavallée recommended to the GAP region, were lower than those of Hönüsü. On the other hand the GAP region cultivars Ağ Besni, Rumi, Kabarcık, Dımıþkı and the recommended cultivars Razakı and Italia were significantly different in their expression levels. Among rootstocks 1616 C displayed the highest expression level, followed by 99R; they were followed by 1613C. In 110R the expression level was slightly lower than in the above mentioned ones and 41B. In SO4 and 5C the level of expression remained at the control level.

Molecular discrimination and identification of some Turkish grape cultivars (Vitis vinifera L.) by RAPD markers

Research Note

Computational study of scattering from healthy and diseased red blood cells

We present a comparative study of scattering from healthy red blood cells (RBCs) and diseased RBCs with deformed shapes. Scattering problems involving three-dimensional RBCs are formulated accurately with the electric and magnetic current combined-field integral equation and solved efficiently by the multilevel fast multipole algorithm. We compare scattering cross section values obtained for different RBC shapes and different orientations. In this way, we determine strict guidelines to distinguish deformed RBCs from healthy RBCs and to diagnose various diseases using scattering cross section values. The results may be useful for designing new and improved flow cytometry procedures. © 2010 Society of Photo Optical Instrumentation Engineers

PO-MLFMA hybrid technique for the solution of electromagnetic scattering problems involving complex targets

The multilevel fast multipole algorithm (MLFMA) is a powerful tool for efficient and accurate solutions of electromagnetic scattering problems involving large and complicated structures. On the other hand, it is still desirable to increase the efficiency of the solutions further by combining the MLFMA implementations with the high- frequency techniques such as the physical optics (PO). In this paper, we present our efforts in order to reduce the computational cost of the MLFMA solutions by introducing PO currents appropriately on the scatterer. Since PO is valid only on smooth and large surfaces that are illuminated strongly by the incident fields, accurate solutions require careful choices of the PO and MLFMA regions. Our hybrid technique is useful especially when multiple solutions are required for different frequencies, illuminations, and scenarios, so that the direct solutions with MLFMA become expensive. For these problems, we easily accelerate the MLFMA solutions by systematically introducing the PO currents and reducing the matrix dimensions without sacrificing the accuracy

Solutions of large-scale electromagnetics problems using an iterative inner-outer scheme with ordinary and approximate multilevel fast multipole algorithms

We present an iterative inner-outer scheme for the efficient solution of large-scale electromagnetics problems involving perfectly-conducting objects formulated with surface integral equations. Problems are solved by employing the multilevel fast multipole algorithm (MLFMA) on parallel computer systems. In order to construct a robust preconditioner, we develop an approximate MLFMA (AMLFMA) by systematically increasing the efficiency of the ordinary MLFMA. Using a flexible outer solver, iterative MLFMA solutions are accelerated via an inner iterative solver, employing AMLFMA and serving as a preconditioner to the outer solver. The resulting implementation is tested on various electromagnetics problems involving both open and closed conductors. We show that the processing time decreases significantly using the proposed method, compared to the solutions obtained with conventional preconditioners in the literature

Electromagnetic modeling of split-ring resonators

In this paper, we report our efforts to model splitring resonators (SRRs) and their large arrays accurately and efficiently in a sophisticated simulation environment based on recent advances in the computational electromagnetics. The resulting linear system obtained from the simultaneous discretization of the geometry and Maxwell's equations is solved iteratively with the multilevel fast multipole algorithm. As an example, we present an array of 125 SRRs showing a negative effective permeability about 92 GHz. © 2006 EuMA

MLFMA solutions of transmission problems Involving realistic metamaterial walls

We present the solution of multilayer metamaterial (MM) structures containing large numbers of unit cells, such as split-ring resonators. Integral-equation formulations of scattering problems are solved iteratively by employing a parallel implementation of the multilevel fast multipole algorithm. Due to ill-conditioned nature of the problems, advanced preconditioning techniques are used to obtain rapid convergence in the iterative solutions. By constructing a sophisticated simulation environment, we accurately and efficiently investigate large and complicated MM structures. © 2007 IEEE

Accurate modeling of metamaterials with MLFMA

Electromagnetic modelling of large metamaterial (MM) structures employing multilevel fast multipole algorithm (MLFMA) is reported. MMs are usually constructed by periodically embedding unit cells, such as split-ring resonators (SRRs), into a host medium. Without utilizing any homogenization techniques, we accurately model large numbers of unit cells that translate into very large computational problems. By considering all of the electromagnetic interactions, the resulting dense matrix equations are solved iteratively with the accelerated matrix-vector products by MLFMA. To increase the efficiency, we also employ parallel computing in the solutions of large SRR problems

Hybridizing physical optics with MLFMA for efficient scattering computations of three-dimensional complex targets

The multilevel fast multipole algorithm (MLFMA) provides accurate and efficient solutions of electromagnetic scattering problems involving large and complicated structures. On the other hand, whenever applicable, accelerations provided by approximation techniques can be useful to further improve the efficiency of solutions. In this paper, we present a hybrid technique, which combines the physical-optics (PO) method and MLFMA for efficient scattering computations of three-dimensional objects. We show that, with a careful choice of MLFMA and PO regions on the structure, the number of unknowns can be reduced and solutions can be accelerated significantly, without sacrificing the accuracy. The proposed hybrid technique is easy to implement by modifying existing MLFMA codes. ©2009 IEEE

Rigorous solutions of scattering problems involving red blood cells

We present rigorous solutions of scattering problems involving healthy red blood cells (RBCs) and diseased RBCs with deformed shapes. Scattering cross-section (SCS) values for different RBC shapes and different orientations are obtained accurately and efficiently using a sophisticated simulation environment based on the electric and magnetic current combinedfield integral equation and the multilevel fast multipole algorithm. Using SCS values, we determine strict guidelines to distinguish deformed RBCs from healthy RBCs and to diagnose related diseases