A Product–Delay algorithm for graphic design

A Product–Delay algorithm is presented for creating graphic designs on a computer. In this algorithm two functions u(t) and v(t) are multiplied yielding a function x(t). Another function y(t) is formed by delaying or advancing x(t) by a fixed amount of time t. These functions are evaluated over a suitable time interval and the results are plotted in the x–y plane. For appropriate choices of the functions and parameters, the x–y displays exhibit interesting geometric patterns. In this paper the algorithm is illustrated with a pair of sine and square waves. It is shown that a wide variety of graphic designs can be created with these simple waveforms. By virtue of its simplicity this algorithm can be programmed easily and quickly using general purpose software such as Maple, Matlab or Mathematica. It can be executed on standard platforms such as IBM PC compatibles, Macintosh computers or workstations. Some results in polar coordinates are also given.     

Synergistic induction of phospholipid metabolism by granulocyte-macrophage colony stimulating factor and steel factor in human growth factor-dependent cell line,M07e

Steel factor (SLF), the ligand for the c-kit protooncogene tyrosine kinase receptor, synergizes with several hematopoietic growth factors to produce greatly enhanced proliferation of normal human hematopoietic progenitor cells as well as that of the human growth factor-dependent myeloid cell line, M07e. The mechanisms of this phenomenon remain unknown. In an attempt to understand the cellular processes relevant to this phenomenon, we examined the effects of SLF and granulocyte-macrophage colony-stimulating factor (GM-CSF) on induced lipid metabolism in M07e cells. We find that both GM-CSF and SLF induced increased phosphatidylcholine (PC) turnover rates (biosynthesis and degradation) as measured by increased [³H]-choline labelling, with SLF being more potent stimulation. The labelling of aqueous intermediates of PC metabolism was also increased by cytokine stimulation, most notably phosphocholine. Simultaneous stimulation with GM-CSF plus SLF resulted in a true synergistic induction of PC, lysoPC, and phosphocholine labelling. GM-CSF and SLF each induced asymmetric labelling of various phospholipid classes as measured by incorporation of different [³H]-fatty acids. [³H]-myristic acid labelling of phosphatidylserine was most prominently induced (approximately 12-fold). Cytosolic choline kinase activity was also upregulated more than twofold over control by SLF, which might contribute to the increased phosphocholine labelling. These effects may have relevance to the intracellular mechanisms of the synergistic proliferative stimulation of SLF plus GM-CSF on M07e cells.     

Two-material optimization of plate armour for blast mitigation using hybrid cellular automata

With the increased use of improvised explosive devices in regions at war, the threat to military and civilian life has risen. Cabin penetration and gross acceleration are the primary threats in an explosive event. Cabin penetration crushes occupants, damaging the lower body. Acceleration causes death at high magnitudes. This investigation develops a process of designing armour that simultaneously mitigates cabin penetration and acceleration. The hybrid cellular automaton (HCA) method of topology optimization has proven efficient and robust in problems involving large, plastic deformations such as crash impact. Here HCA is extended to the design of armour under blast loading. The ability to distribute two metallic phases, as opposed to one material and void, is also added. The blast wave energy transforms on impact into internal energy (IE) inside the solid medium. Maximum attenuation occurs with maximized IE. The resulting structures show HCA's potential for designing blast mitigating armour structures.     

Hardware Organization to Achieve High-Speed Elliptic Curve Cryptography for Mobile Devices

Elliptic curve cryptography (ECC) is recognized as a fast cryptography system and has many applications in security systems. In this paper, a novel sharing scheme is proposed to significantly reduce the number of field multiplications and the usage of lookup tables, providing high speed operations for both hardware and software realizations.

Hardware Implementation of Block-based Motion Estimation for Real Time Applications

This work describes the VHDL design and implementation of block-based motion estimation in order to make it feasible for real-time video applications. The design was functionally tested and simulated using ModelSim from Mentor Graphics tools, and then verified using both a VHDL testbench and the Matlab? Image processing tools. The design was tested for different image sizes at different clock frequencies with varying block sizes and search areas. With a clock frequency of 400 MHz, the estimated time for motion estimation for QCIF and CIF sequences shows the feasibility for real-time video-codec.

Inhibition of Mycobacterium tuberculosis methionine aminopeptidases by bengamide derivatives

Methionine aminopeptidase (MetAP) carries out an essential function of protein N‐terminal processing in many bacteria and is a promising target for the development of novel antitubercular agents. Natural bengamides potently inhibit the proliferation of mammalian cells by targeting MetAP enzymes, and the X‐ray crystal structure of human type 2 MetAP in complex with a bengamide derivative reveals the key interactions at the active site. By preserving the interactions with the conserved residues inside the binding pocket while exploring the differences between bacterial and human MetAPs around the binding pocket, seven bengamide derivatives were synthesized and evaluated for inhibition of MtMetAP1a and MtMetAP1c in different metalloforms, inhibition of M. tuberculosis growth in replicating and non‐replicating states, and inhibition of human K562 cell growth. Potent inhibition of MtMetAP1a and MtMetAP1c and modest growth inhibition of M. tuberculosis were observed for some of these derivatives. Crystal structures of MtMetAP1c in complex with two of the derivatives provided valuable structural information for improvement of these inhibitors for potency and selectivity.     

Boostcharging Li-ion batteries: A challenging new charging concept

Boostcharging is proposed as a new, ultra-fast, recharging algorithm for Li-ion batteries. Characteristic for boostcharging is that close-to-fully discharged batteries can be recharged with very high currents for a short period of time. Cycle life of Li-ion batteries, boostcharged and additionally standard charged to full capacity do not introduce any negative degradation effects. Boostcharging is shown to be very rapid. For example, a fully discharged battery can be recharged within 5 min to one-third of its rated capacity.     

Self-assembly and bioactive response of a crystalline metal oxide in a simulated blood fluid

In this study we report on the bioactive response of self-assembled niobium oxide microstructures when immersed in a supersaturated solution emulating mineral content in blood. The structures were formed via electrochemical anodization in an electrolyte comprised of HF and NaF. The slow oxide formation kinetics associated with the presence of NaF in the electrolyte enabled microscopic examinations during microstructure evolution as shown via scanning electron microscopy (SEM). Apparently the slow growth kinetics encourage the development of bioactive sites on the microstructures, as these structures induced mineral formations. On the other hand, microstructures grown in the absence of salt were ineffective mineral nucleators. Analysis of nucleated mineral deposits was performed using X-ray diffraction and Raman spectroscopy. Both long-range and short-range order experiments verified the nucleated mineral phase was hydroxyapatite (HAP). Further characterization of the mineral phase was observed using SEM and revealed effective nucleation sites were predominantly isolated to loci on the ordered microbodies as opposed to locations lying within the amorphous strata.     

Sintering of aluminum nanoparticles: A molecular dynamics study

Molecular-dynamics simulations have been used to study the consolidation of nanopartictes of aluminum. We have studied two- and three-particle sintering as it is influenced by temperature, particle size and crystallographic orientation. We have elucidated the dominant transport mechanisms by measuring the shear stresses that develop in the contact regions and the mobilities of the surface and core atoms during sintering. Our studies demonstrate that increasing the particles size slows down the sintering kinetics. The extent of interpenetration of the particles is independent of the particle size and is afunction of the temperature of the particles.