Power savings analysis of clipping and filtering method in OFDM systems

The clipping and filtering method is analyzed in terms of power savings. The analysis takes account of the gain in the amplifier efficiency due to peak-to-average-power-ratio (PAPR) reduction. Assuming a linear amplifier and a typical digital signal processor, the power savings is shown to be in the order of Watts

Single-bit adaptive channel equalization for narrowband signals

In this paper, a new design of a single-bit adaptive channel equalization is proposed using sigma delta modulation and a single-bit block Least Mean Square (LMS) algorithm. With correlated narrowband input signals, this model is capable to converge and provide equivalent equalization filter with improvement in the SNR and very low Symbol Error Rate (SER). The input, filter coefficients and output values are all in single-bit and ternary format that results in a reduction in hardware complexity compared to traditional multi-bit channel equalization. Additionally, the technique avoids the need for successive conversion from multi-bit to single bit and back at the receiver and transmitter stages

Effect of some natural antioxidants on aflatoxin B1-induced hepatic toxicity

Aflatoxins are potent hepatotoxic and hepatocarcinogenic agents. This hepatotoxicity is thought to be mediated by their ability to generate reactive oxygen species and cause peroxidative damage. In the present investigation we assessed the ability of some natural antioxidants namely, vitamin E and Se, ß-carotene, silymarin and coenzyme Q10 on aflatoxin B1 (AFB1)-induced hepatotoxicity in a rat model. Alanine and aspartate aminotransferases and alkaline phosphatase (ALP) were found to be significantly increased in the serum of AFB1 administered (250 µg/kg body weight/day for 2 weeks) rats, suggesting hepatic damage. There was a marked increase in the lipid peroxide levels and a concomitant decrease in the hepatic reduced glutathione (GSH) and serum protein thiol (PrSHs) along with a nearly twofold increase in hepatic glutathione-S-transferase (GST) activity. The significant increase in GST may be attributed to its being a phase ?? enzyme that predominately participates in the detoxification of the ultimate electrophilic metabolite AFB1-8, 9 epoxide. On the other hand, no significant change was detected in the activities of glutathione peroxidase (GPx), glutathione reductase (GR), glucose-6-phosphate dehydrogenase (G-6-PDH), cytochrome creductase and levels of DNA and RNA in the hepatic tissue of AFB1 administered rats. Results also revealed that cotreatment with studied antioxidants offered substantial hepatoprotective effects in the AFB1 administered rats. Moreover, results revealed that vitamin E and selenium combination and ß-carotene are more efficient than coenzyme Q10 and silymarin in modulating the liver antioxidant enzymatic system

Non-Standard Intersections of S-Branes in D=11 Supergravity

We construct new intersecting S-brane solutions in 11-dimensional supergravity which do not have supersymmetric analogs. They are obtained by letting brane charges to be proportional to each other. Solutions fall into two categories with respect to whether there is a non-diagonal term to be cancelled in the field equations or not. In each case we show that they can be constructed by using a simple set of rules which is similar to the harmonic function rule of the usual static p-branes. Furthermore, we study an intersection where the Chern-Simons term makes a non-zero contribution to the field equations. We show that this configuration has a singularity like other S-branes.Comment: 13 pages, 2 figures;v2 Section 2.2 is improved with new examples, references added;v3 typos correcte

Multi-port, optically addressed RAM

A random access memory addressing system utilizing optical links between memory and the read/write logic circuits comprises addressing circuits including a plurality of light signal sources, a plurality of optical gates including optical detectors associated with the memory cells, and a holographic optical element adapted to reflect and direct the light signals to the desired memory cell locations. More particularly, it is a multi-port, binary computer memory for interfacing with a plurality of computers. There are a plurality of storage cells for containing bits of binary information, the storage cells being disposed at the intersections of a plurality of row conductors and a plurality of column conductors. There is interfacing logic for receiving information from the computers directing access to ones of the storage cells. There are first light sources associated with the interfacing logic for transmitting a first light beam with the access information modulated thereon. First light detectors are associated with the storage cells for receiving the first light beam, for generating an electrical signal containing the access information, and for conducting the electrical signal to the one of the storage cells to which it is directed. There are holographic optical elements for reflecting the first light beam from the first light sources to the first light detectors

Selection of DNA nanoparticles with preferential binding to aggregated protein target.

High affinity and specificity are considered essential for affinity reagents and molecularly-targeted therapeutics, such as monoclonal antibodies. However, life's own molecular and cellular machinery consists of lower affinity, highly multivalent interactions that are metastable, but easily reversible or displaceable. With this inspiration, we have developed a DNA-based reagent platform that uses massive avidity to achieve stable, but reversible specific recognition of polyvalent targets. We have previously selected these DNA reagents, termed DeNAno, against various cells and now we demonstrate that DeNAno specific for protein targets can also be selected. DeNAno were selected against streptavidin-, rituximab- and bevacizumab-coated beads. Binding was stable for weeks and unaffected by the presence of soluble target proteins, yet readily competed by natural or synthetic ligands of the target proteins. Thus DeNAno particles are a novel biomolecular recognition agent whose orthogonal use of avidity over affinity results in uniquely stable yet reversible binding interactions

Beta, Dipole and Noncommutative Deformations of M-theory Backgrounds with One or More Parameters

We construct new M-theory solutions starting from those that contain 5 U(1) isometries. We do this by reducing along one of the 5-torus directions, then T-dualizing via the action of an O(4,4) matrix and lifting back to 11-dimensions. The particular T-duality transformation is a sequence of O(2,2) transformations embedded in O(4,4), where the action of each O(2,2) gives a Lunin-Maldacena deformation in 10-dimensions. We find general formulas for the metric and 4-form field of single and multiparameter deformed solutions, when the 4-form of the initial 11-dimensional background has at most one leg along the 5-torus. All the deformation terms in the new solutions are given in terms of subdeterminants of a 5x5 matrix, which represents the metric on the 5-torus. We apply these results to several M-theory backgrounds of the type AdS_r x X^{11-r}. By appropriate choices of the T-duality and reduction directions we obtain analogues of beta, dipole and noncommutative deformations. We also provide formulas for backgrounds with only 3 or 4 U(1) isometries and study a case, for which our assumption for the 4-form field is violated.Comment: v2:minor corrections, v3:small improvements, v4:conclusions expanded, to appear in Class. Quant. Gra

Experimental and theoretical investigation of ligand effects on the synthesis of ZnO nanoparticles

ZnO nanoparticles with highly controllable particle sizes(less than 10 nm) were synthesized using organic capping ligands in Zn(Ac)2 ethanolic solution. The molecular structure of the ligands was found to have significant influence on the particle size. The multi-functional molecule tris(hydroxymethyl)-aminomethane (THMA) favoured smaller particle distributions compared with ligands possessing long hydrocarbon chains that are more frequently employed. The adsorption of capping ligands on ZnnOn crystal nuclei (where n = 4 or 18 molecular clusters of(0001) ZnO surfaces) was modelled by ab initio methods at the density functional theory (DFT) level. For the molecules examined, chemisorption proceeded via the formation of Zn...O, Zn...N, or Zn...S chemical bonds between the ligands and active Zn2+ sites on ZnO surfaces. The DFT results indicated that THMA binds more strongly to the ZnO surface than other ligands, suggesting that this molecule is very effective at stabilizing ZnO nanoparticle surfaces. This study, therefore, provides new insight into the correlation between the molecular structure of capping ligands and the morphology of metal oxide nanostructures formed in their presence

Fluidization behavior of sand particles with a size distribution

Fluidization technology has a wide range of applications in industries due to its unique ability to transport solid particles and for uniform heat transfer. But this technology is dependent on the properties of bed material. It is essential to determine the hydrodynamics behavior such as minimum fluidization velocity of bed material. During operation, particles with low mechanical strength experienced attrition. Particle attrition increases operating cost, instability, and decreases reactor or bed performance. Also, due to attrition minimum fluidization velocity will change. The core aim of this study is to understand how minimum fluidization velocity will alter if particle size distribution changes due to particle attrition. In this work, a literature study about the minimum fluidization velocity of poly-dispersed particles, and developed correlations was conducted. Minimum fluidization velocity was determined from the experimental data of different-size particle samples. The minimum fluidization velocity of the original sample was compared with other samples. The results show that minimum fluidization velocity decreases with the reduction of the size of particles. The presence of a considerable number of small particles can alter the minimum fluidization velocity of the sample. At packed bed condition, pressure drops show linear relation with gas velocity. The results also show that minimum fluidization velocity can be the same for different mean diameters. Finally, some correlations can predict the minimum fluidization velocity of particles with good accuracy