Relay with deflection routing for effective throughput improvement in Gbps millimeter-wave WPAN systems

In this paper, we propose a deflection routing scheme that improves effective throughput (defined as the successfully transmitted bits over the duration between two available sequential time slots) of millimeter-wave wireless personal area network (mmWave WPAN) systems. The upcoming mmWave WPAN is based on dynamic time division multiple access (TDMA) and designed to guarantee Gbps-order transmission capability for high definition TV (HDTV) transmission, high speed wireless docking and gaming, etc. The decode-and-forward (DF) type of relay offers a simple solution to the issues of mmWave WPAN systems, such as limited coverage range and unexpected blockage. However, due to the required extra time, DF relay on the other hand decreases the effective throughput, and may not be sufficient to satisfy the requirement of the above data-rate-greedy applications. Inspired by the fact that the significant path loss of a millimeter-wave environment can provide good space isolation, we propose a deflection routing scheme to improve the effective throughput by sharing time slots for direct path with relay path. Based on the sub-exhaustive search, a routing algorithm, named as best fit deflection routing (BFDR), has been developed to find the relay path with the least interference that maximizes the system throughput. To reduce the computational complexity of the BFDR, we have also developed a sub-optimal algorithm named as random fit deflection routing (RFDR). The RFDR algorithm finds the sub-optimized relay path, where the interference may not be the least but is sufficiently low to guarantee the concurrent transmissions. Computer simulations show that, in realistic 60 GHz environments, the effective system throughput can be improved up to 28% under grid topology and 35% under random topology. RFDR achieves almost the same order of throughput improvement with only 10% of the computational complexity of BFDR.     

Synergic effect of vanadium trichloride on the reversible hydrogen storage performance of the MgMgH2 system

Vanadium trichloride (VCl₃) is one of the best catalysts for the hydrogenation-dehydrogenation MgMgH₂ system. X-ray photoelectron spectroscopy (XPS) has shown that VCl₃ reduced to metallic vanadium during ball milling along with MgH₂. The in-situ-formed metallic vanadium doped over the MgH₂ surface which has shown an excellent catalytic effect on hydrogenation-dehydrogenation of the MgMgH₂ system. The catalyzed surface reduced the activation energies of hydrogenation-dehydrogenation reactions and correspondingly on-set hydrogenation-dehydrogenation temperatures. The microstructural analysis has also shown an excellent grain refinement property of VCl₃ which reduced the crystallite size of MgH₂. The decreased crystallite size decreases the diffusion path length of hydrogen and increases the active surface area which eventually enhances the hydrogenation-dehydrogenation kinetics of MgMgH₂.     

ESR and optical absorption spectra of Ni(II) ions in lithium fluoroborate glasses

The results of the investigation of the structure of Ni(II) ions in x LiF-(100–x) B₂O₃ glasses with 5x30 mol% using ESR and optical absorption techniques are reported. Electron spin resonance spectra of Ni(II) ions doped glasses exhibit a symmetric line shape centred at g=2.36±0.01 at room temperature. Remarkable changes have been observed in the intensity and line shape with changes in concentration of LiF and when the spectra were recorded in the temperature range 123–453 K. The optical absorption spectra were recorded at room temperature. The observed bands have been interpreted in terms of ligand field theory. From the spectral analysis, the crystal field parameter, Dq, and the Racah interelectronic repulsion parameters, B and C, have been evaluated. By correlating the ESR and optical absorption data, the covalency parameter has been evaluated.     

Efficacy of 6-chloro-2'',3''-dideoxyguanosine (6-Cl-ddG) on rhesus macaque monkeys chronically infected with simian immunodeficiency virus (SIVmac239)

The object of the present work was to study the relationship between acute pancreatitis (PA) and hyperlipidic diets. PA was induced by Caerulein (CE) by a single intraperitoneal doses (50 mcg/kg), after feeding the rats during 6 weeks with an hyperlipidic diet (45%). Rats with a normolipidic diet (lipids 5%) were used as control. The increase of serum lipase was similar in both groups treated with CE (control and with hyperlipidic diet). There were increase of interstitial edema, cariorrexis and a specially marked increase in the level of vacuolization of acinar cells with respect to the control group. It was concluded that chronic hyperlipidic diet increases histopathologic lesions in PA induced by CE in rats.     

Antimicrobial activity of newly synthesized isothiocyanate derivatives against pathogenic plant microorganisms

Fifteen reaction products of isothiocyanates with cysteine, seven reaction products of isothiocyanates with 2,3-dimercapto-1-propanol, and four reaction products of isothiocyanates with sulfanilamide were synthesized. Their antimicrobial activity against pathogenic plant microorganisms was investigated.     

Engineering a chimeric pyrroloquinoline quinone glucose dehydrogenase: improvement of EDTA tolerance, thermal stability and substrate specificity

An engineered Escherichia coli PQQ glucose dehydrogenase (PQQGDH)with improved enzymatic characteristics was constructed by substitutingand combining the gene-encoding protein regions responsiblefor EDTA tolerance, thermal stability and substrate specificity.The protein region responsible for complete EDTA tolerance inAcinetobacter calcoaceticus, which is recognized as the indicatorof high stability in co-factor binding, was elucidated. Theregion is located between 32 and 59% from the N-terminus ofA.calcoaceticus PQQGDH(A27 region) and also corressponds tothe same position from 32 to 59% from the N-terminus in E.coliPQQGDH, though E.coli PQQGDH is EDTA sensitive. We previouslyreported that the C-terminal 3% region of A.calcoaceticus (A3region) played an important role in the increase of thermalstability, and that His775Asn substitution in E.coli PQQGDHresulted in an increase in the substrate specificity of E.coliPQQGDH towards glucose. Based on these findings, chimeric and/ormutated PQQGDHs, E97A3 H775N, E32A27E41 H782N, E32A27E38A3 andE32A27E38A3 H782N were constructed to investigate the compatibilityof two protein regions and one amino acid substitution. His775substitution to Asn corresponded to His782 substitution to Asn(H782N) in chimeric enzymes harbouring the A27 region. Sinceall the chimeric PQQGDHs harbouring the A27 region were EDTAtolerant, the A27 region was found to be compatible with theother region and substituted amino acid responsible for theimprovement of enzymatic properties. The contribution of theA3 region to thermal stability complemented the decrease inthe thermal stability due to the His775 or His782 substitutionto Asn. E32A27E38A3 H782N, which harbours all the above mentionedthree regions, showed improved EDTA tolerance, thermal stabilityand substrate specificity. These results suggested a strategyfor the construction of a semi-artificial enzyme by substitutingand combining the gene-encoding protein regions responsiblefor the improvement of enzyme characteristics. The characteristicsof constructed chimeric PQQGDH are discussed based on the predictedmodel, ß-propeller structure.     

The polycondensation of lithium 11–bromoundecanoate in aqueous media

To obtain a biodegradable plastic, polycondensation, the substitution of bromine by carboxylate was carried out on lithium 11–bromoundecanoate. Using water as a solvent, the formation of a double bond was detected between 70 and 100°C, yielding a good quantity of polymer. Water is recommended as the best solvent for the reaction. Thermodynamic investigations were carried out by using ethylene glycol and water. The reaction is believed to proceed according to the S_N2 mechanism. The ΔH and ΔG values for condensation in ethylene glycol were slightly higher than for those in water, but the reaction rate in water at 70°C was 7 times greater than that in ethylene glycol. The enhancement of dissociation accounts for the advantageous condensation in aqueous media. Furthermore, ΔS shows negative values and ΔG shows positive values, meaning that the reaction should proceed exothermically and not spontaneously. Experiments to condense 11–bromoundecanoate in aqueous media were carried out for ten days in a water bath, kept at 70°C, using 25 mL of 0.05M 11–bromoundecanoate. The degree of polymerization for the resulting polymer was found to be 23 by the end group assay for both bromine and carboxylate. Neither a melting point nor glass transition point for the product were observed. The polymer formed decomposes at 300°C and instantly disperses. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 130–134, 2003     

Halochromism of acrylic fibres dyed with some disperse dyes

Anomalous dyeing behaviour has been found when regular acrylic fibre treated in hydrochloric acid, in which the sulphonic acid group was present entirely in the acid form, was dyed in neutral condition with azo and anthraquinone disperse dyes. In the very early stages of dyeing there was an abnormally high degree of dye exhaustion, with bathochromic (azo) or hypsochromic (anthraquinone) colour changes on the fibre. These phenomena gradually disappeared after prolonged dyeing, with normal adsorption equilibria and colours eventually being obtained. The results were explained on the basis of protonation by the sulphonic acid groups of treated fibre which occurs at the azo nitrogen or the amino nitrogens of the substituents in the 1 — or 1,4-positions of anthraquinone. The normal adsorption equilibria after prolonged dyeing was attributed to hydrolysis of the cyano side group to form carboxylic acid. This produces ammonia to liberate neutral dye from the protonated dye cation adsorbed electrostatically by the sulphonic acid anion of the treated fibre.     

Effect of hot extrusion on microstructure and mechanical properties of quasicrystal-reinforced Mg-Zn-Y alloy

The microstructure and mechanical properties of as-cast and as-extruded Mg-Zn-Y alloy （Mg-11 %Zn- 0.9%Y, mass fraction） containing Mg3 YZn6 quasicrystal were studied. The eutectic icosahedral quasicrystal phase （I-phase） is broken and almost distributes along the extrusion direction, and fine I-phase with nano-size is precipitated during the extrusion. The a-Mg matrix grains are refined due to recrystallization occuring during the hot extrusion. Some {1012} twins are observed in the extruded ZW1101 alloy. And {0002}（1010） fiber texture is formed in matrix alloys after hot extrusion. The extruded alloy exhibits high strength in combination with large elongation at room temperature. The strengthening mechanism of the as-extruded alloy was discussed.     

Synthesis,characterization and thermal properties of homo and copolymers of 3,5-dimethoxyphenyl methacrylate with glycidyl methacrylate: Determination of monomer reactivity ratios

The new methacrylic monomer, 3,5-dimethoxyphenyl methacrylate (DMOPM) was synthesized by reacting 3,5-dimethoxyphenol dissolved in ethyl methyl ketone (EMK) with methacryloyl chloride in presence of triethylamine as a catalyst. The homopolymer and copolymers of DMOPM with glycidyl methacrylate (GMA) were synthesized by free radical polymerization in EMK solution at 70 ± 1 °C using benzoyl peroxide as a free radical initiator. The copolymerization behaviour was studied in a wide composition interval with the mole fractions of DMOPM ranging from 0.15 to 0.9 in the feed. The homopolymer and the copolymers were characterized by FT-IR, ¹H NMR and ¹³C NMR spectroscopic techniques. The solubility was tested in various polar and non-polar solvents. The molecular weight and polydispersity indices of the polymers were determined using gel permeation chromatography. The glass transition temperature of the copolymers increases with increase in DMOPM content. The thermogravimetric analysis of the polymers showed that the thermal stability of the copolymer increases with DMOPM content. The copolymer composition was determined using ¹H NMR spectra. The monomer reactivity ratios were determined by the application of conventional linearization methods such as Fineman–Ross (r₁ = 0.520, r₂ = 2.521), Kelen–Tudos (r₁ = 0.629, r₂ = 2.554) and extended Kelen–Tudos methods (r₁ = 0.600, r₂ = 2.502).