Designing and experimentally demonstrating automatic OPS/OCS/OpenFlow network control driven by ChoiceNet provider

Interconnection between our existing optical packet and circuit integrated network (OPCInet) and an ecosystem for network service provisioning named ChoiceNet enables network service providers to provide diverse services and realize control driven by the providers. In this paper, we design and implement control interfaces for the interconnection, which enables each ChoiceNet provider to explicitly control both OPCInet- and OpenFlow-based networks by use of a single common interface with proprietary/easily modifiable message formats for all control functions. We construct an experimental setup between the USA and Japan, and demonstrate that the OPCInet and an OpenFlow-based network placed in Japan are successfully controlled by request from the ChoiceNet provider installed in the USA. We also show that the time required to complete Telnet access to the OPCInet C-plane for each control is no more than 150 ms over the long distance from the USA to Japan.     

Solvent polarity induced structural changes in 2,6-diamino-9,10-anthraquinone dye

Photophysical properties of 2,6-diamino-9,10-anthraquinone (2,6-DAAQ) dye have been investigated in different solvents and solvent mixtures. The fluorescence quantum yields, fluorescence lifetimes, radiative rate constants, nonradiative rate constants and absorption and fluorescence spectral characteristics show unusual deviations in the lower polarity aprotic solvents in comparison to those in other aprotic solvents of medium to higher polarities. The results indicate that the dye exists in different structural forms in the lower and in the medium to higher polarity solvents. Drawing an analogy with the results reported for other amino-substituted dyes, it is inferred that 2,6-DAAQ dye adopts a planar intramolecular charge transfer (ICT) structure in medium to higher polarity solvents, where the amino lone pairs are in good resonance with the anthraquinone pi-cloud. In the lower polarity solvents, however, the dye is inferred to exist in a nonplanar structure where the amino lone pairs are not in good resonance with the anthraquinone pi-cloud. Due to these structural differences, the dye displays significantly different photophysical behavior in the lower polarity solvents than in the other solvents of medium to higher polarities. Supportive evidence for the above structural changes has been obtained from ab initio quantum chemical calculations on the structures of the dye under different conditions. Unusual deviations in the photophysical properties of 2,6-DAAQ dye in protic solvents in comparison to those in aprotic solvents of similar polarities are attributed to the intermolecular hydrogen bonding effect involving the OH groups of the protic solvents and the quinonoid oxygens of the dye.     

Gd-complexes of DTPA-bis(amide) conjugates of tranexamic acid and its esters with high relaxivity and stability for magnetic resonance imaging

The synthesis and the characterization of a series of DTPA-bis(amide) conjugates of tranexamic acid (L1), its esters (L2-L6), and their Gd(III) complexes of the type [Gd(L)(H2O)].nH2O (L = L1-L6) are described. Except for the case of , all Gd-complexes exhibit greatly enhanced R1 relaxivity. Highest R1 reaches up to 12.9 mM(-1) s(-1) for [Gd(L2)(H2O)]. Such high relaxivity is reflected in the intensity enhancement of the in vivo MRI study on H-ras transgenic mice bearing hepatic tumor when employing [Gd(L2)(H2O)] as an MRI contrast agent. Thermodynamic stability constants, conditional stability constants, and the pM values demonstrate higher stability of [Gd(L)(H2O)].nH2O (L =L1-L6) than Omniscan under physiological conditions. The MTT assay performed on these complexes reveals cytotoxicity as low as that for Omniscan in the concentration range required to obtain intensity enhancement in the in vivo MRI study.     

Measurement of soil/dust arsenic by gas phase chemiluminescence

A gas phase chemiluminescence (GPCL)-based method for trace measurement of arsenic has been recently described for the measurement of arsenic in water. The principle is based on the reduction of inorganic As to AsH₃ at a controlled pH (the choice of pH governs whether only As(III) or all inorganic As is converted) and the reaction of AsH₃ with O₃ to produce chemiluminescence (Idowu et al., Anal. Chem. 78 (2006) 7088-7097). The same general principle has also been used in postcolumn reaction detection of As, where As species are separated chromatographically, then converted into inorganic As by passing through a UV photochemical reactor followed by AsH₃ generation and CL reaction with ozone (Idowu and Dasgupta, Anal. Chem. 79 (2007) 9197-9204). In the present paper we describe the measurement of As in different soil and dust samples by serial extraction with water, citric acid, sulfuric acid and nitric acid. We also compare parallel measurements for total As by induction coupled plasma mass spectrometry (ICP-MS). As(V) was the only species found in our samples. Because of chloride interference of isobaric ArCl⁺ ICP-MS analyses could only be carried out by standard addition; these results were highly correlated with direct GPCL and LC-GPCL results (r² = 0.9935 and 1.0000, respectively). The limit of detection (LOD) in the extracts was 0.36 μg/L by direct GPCL compared to 0.1 μg/L by ICP-MS. In sulfuric acid-based extracts, the LC-GPCL method provided LODs inferior to those previously observed for water-based standards and were 2.6, 1.3, 6.7, and 6.4 μg/L for As(III), As(V), dimethylarsinic acid (DMA) and monomethylarsonic acid (MMA), respectively.     

A stereodefined approach towards the bicyclo[3.3.1]nonan-9-one core of the phloroglucin natural products guttiferone A and hypersampsone F

An approach towards the highly functionalized bicyclo[3.3.1]nonan-9-one core present in the phloroglucin natural products guttiferone A and hypersampsone F is disclosed in which the key C7 and C8 stereogenic centres have been successfully installed.     

Regioselective Difunctionalization and Annulation of Ynamide

The use of ynamides in organic synthesis has gained significant attention due to their ability to provide access to complex molecular structures through transformations such as 1,2-difunctionalization and annulation reactions. These reactions enable the formation of highly functionalized N-bearing olefins and unusual N-bearing heterocycles. In this minireview, we present a systematic overview of the regioselective difunctionalization and annulation reactions of ynamides. We discuss the multi-component reactions, and radical-triggered functionalizations across the ynamides carbon–carbon multiple bonds and the use of bifunctional reagents in annulation of ynamides, highlighting their potential in expanding the substrate scope. Furthermore, we provide insights into the mechanistic breakthroughs that have been achieved in recent years in the development of these reactions. Finally, we emphasize the promising future prospects of ynamides as versatile building blocks for the synthesis of complex molecular architectures.     

Self-propagating assembly of a molecular-based multilayer

Accelerated growth of a molecular-based material that is an active participant in its continuing self-propagated assembly has been demonstrated. This nonlinear growth process involves diffusion of palladium into a network consisting of metal-based chromophores linked via palladium.     

Fast enzyme dynamics at the active site of formate dehydrogenase

The role of femtosecond-picosecond structural dynamics of proteins in enzyme-catalyzed reactions is a hotly debated topic. We report infrared photon echo measurement of the formate dehydrogenase-NAD+-azide ternary complex. In contrast to earlier studies of protein dynamics, the data show complete spectral diffusion on the femtosecond-picosecond time scale with no static heterogeneity. This result indicates that this transition-state analogue complex completely samples the distribution of structures that determine the distribution of azide vibrational frequencies within a few picoseconds and that there are no slower motions that perturb the H-bond network at the active site.     

Influence of the electronics of the phosphine ligands on the H-H bond elongation in dihydrogen complexes

Five new monocationic dihydrogen complexes of ruthenium of the type trans-[RuCl(eta(2)-H(2))(PP)(2)][BF(4)] (PP = bis-1,2(diarylphosphino)ethane, aryl = p-fluorobenzyl, 1a, benzyl, 2a, m-methylbenzyl, 3a, p-methylbenzyl, 4a, p-isopropylbenzyl, 5a) have been prepared by protonating the precursor hydride complexes trans-[RuCl(H)(PP)(2)] using HBF(4).OEt(2). The dihydrogen complexes are quite stable and have been isolated in the solid state. The intact nature of the H-H bond in these derivatives has been established from the short spin-lattice relaxation times (T1, ms) and observation of substantial H, D couplings in the HD isotopomers. The H-H bond distances (dHH, A) increase systematically from 0.97 to 1.03 A as the electron-donor ability of the substituent on the diphosphine ligand increases from the p-fluorobenzyl to the p-isopropylbenzyl moiety. The d(HH) in trans-[Ru(eta(2)-H(2))(Cl)((C(6)H(5)CH(2))(2)PCH(2)CH(2)P(CH(2)C(6)H(5))(2))(2)][BF(4)], 2a, was found to be 1.08(5) A by X-ray crystallography. In addition, two new 16-electron dicationic dihydrogen complexes of the type [Ru(eta(2)-H(2))(PP)(2)][OTf](2) (PP = (ArCH(2))(2)PCH(2)CH(2)P(CH(2)Ar)(2), Ar = m-CH(3)C(6)H(4-), 6a, p-CH(3)C(6)H(4)-, 7a) have also been prepared and characterized. These derivatives were found to possess elongated dihydrogen ligands.     

Priority-based content processing with Q-routing in information-centric networking (ICN)

With exponential increase in the number of users and available data, service providers are facing hard times to satisfy and improve end user experience. Researchers have come up with the idea of exploiting increasing number of routers in a network, and it leads to the development of information-centric networking (ICN). Efficient usage of the in-network caches and content forwarding methodology are the key issues in an ICN architecture. ICN reduces average hop count and correspondingly average content download delay because the intra-domain routers in ICN have storage capacity and they can act as temporary content provider. In this paper, we address the content management issue in a cache with finite storage capability and propose an efficient content management policy that changes a router to a self-sustained cache. We propose a novel methodology to process content packets in the buffer of a cache and correspondingly reduce the propagation delay through a cache. We simulate our proposed algorithm over real-life network environment and evaluate the performance of different user experience metrics, e.g. average latency, throughput, goodput, and link load. Simulation results suggest that our proposed model outperforms the existing state-of-the-art on-path caching strategies.