A reordering-free multipath traffic engineering architecture for DiffServ-MPLS networks

We propose a novel traffic engineering architecture for IP networks with multiprotocol label switching (MPLS) backbones. In this architecture, two (primary and secondary) label switched paths (LSPs) are established among every pair of IP routers located at the edge of an MPLS cloud. Traffic between a source-destination pair is then split between the primary and secondary LSPs using an ABR-like explicit-rate feedback gathered from the network. Taking into consideration the packet reordering effect of packet-based load balancing schemes, we propose a novel traffic splitting mechanism that operates on a per-flow basis. We show, using a variety of scenarios, that deploying flow-based multipath traffic engineering not only provides significantly and consistently better throughput than that of a single path, but is also void of any packet reordering. © 2003 IEEE

External decontamination of wild leeches with hypochloric acid

BACKGROUND: Medicinal leech, Hirudo medicinalis, has been used in plastic and reconstructive surgery, to relieve venous congestion and to improve the microrevascularization of flaps. In many countries, wild leeches are still provided from local markets and utilised with antibiotic prophylaxies. In this research, results of identification of bacteria in the transport fluid is reported, oral and intestinal floras and the antibiograms of the identified microorganisms are investigated. Also, to avoid possible infections, the ability of hypochloric acid, a disinfectant, to suppress the relevant microorganisms without changing the life style and behavior of leeches in terms of sucking function, is investigated. METHODS: Bacterial identifications and antibiograms of oral and intestinal flora and transport medium were performed for 10 leeches. The optimum concentration of hypochloric acid which eliminated microorganisms without affecting the viability and sucking function of the leeches were determined by dilution of hypochloric acid to 100, 50, 25, 12.5, 6.25 ppm concentrations in different groups of 25 leeches. Finally, 20 leeches were applied atraumatically to the bleeding areas of rats, the duration of suction was determined and compared statistically between the leeches treated and not treated with hypochloric acid solution. RESULTS: Aeromonas hydrophilia was the most commonly identified microorganism and found to be resistant to first generation cephalosporins, frequently used in prophylaxis at surgical wards. In the next stages of the study, the leeches were subjected to a series of diluted hypochloric acid solutions. Although disinfection of the transport material and suppression of the oral flora of hirudo medicinalis were successful in 100, 50, 25, 12.5, 6.25 ppm concentrations; 12.5 ppm solution was the greatest concentration in which hirudo medicinalis could survive and sucking function was not affected significantly. CONCLUSIONS: External decontamination of wild leeches with 12.5 ppm hypochloric acid enables bacterial suppression without causing negative effects on leech sucking function and life

ATP and its N6-substituted analogues: parameterization, molecular dynamics simulation and conformational analysis

In this work we used a combination of classical molecular dynamics and simulated annealing techniques to shed more light on the conformational flexibility of 12 adenosine triphosphate (ATP) analogues in a water environment. We present simulations in AMBER force field for ATP and 12 published analogues [Shah et al. (1997) Proc Natl Acad Sci USA 94: 3565–3570]. The calculations were carried out using the generalized Born (GB) solvation model in the presence of the cation Mg2+. The ion was placed at a close distance (2 Å) from the charged oxygen atoms of the beta and gamma phosphate groups of the −3 negatively charged ATP analogue molecules. Analysis of the results revealed the distribution of inter-proton distances H8–H1′ and H8–H2′ versus the torsion angle ψ (C4–N9-C1′–O4′) for all conformations of ATP analogues. There are two gaps in the distribution of torsion angle ψ values: the first is between −30 and 30 degrees and is described by cis-conformation; and the second is between 90 and 175 degrees, which mostly covers a region of anti conformation. Our results compare favorably with results obtained in experimental assays [Jiang and Mao (2002) Polyhedron 21:435–438]

Dimethyl 3,6-dioxatetracyclo[6.1.0.0(2,4).0(5,7)]nonane-2,9-dicarboxylate

The title compound, C11H12O6, has a norcarane structure, which is obtained by the photooxygenation reaction of a cycloheptatriene derivative. The cyclohexane ring is planar. The intermolecular C-H center dot center dot center dot O hydrogen bonds are effective in stabilizing the crystal structure, in which they form parallel infinite chains along the b axis

Intramolecular hydrogen bonding and tautomerism in Schiff bases. Part II. Structures of 1-[N-(2-pyridyl)aminomethylidene}-2(1H)-naphtalenone (1) and bis[2-hydroxy-kappa O-N-(2-pyridyl)-1-naphthaldiminato-kappa N]zinc(II) (2)

Hokelek, Tuncer/0000-0002-8602-4382WOS: 000086678200005The Schiff base ligand (1) and its Zn(II) complex (2) have been synthesized and their crystal structures have been determined. Compound (1) crystallizes in the monoclinic space group C2/c with a = 26.993(2), b = 5.891(1), c = 16.000(2) W, P = 103.29(1)degrees, V = 2476.0(6) Angstrom(3), Z = 8 and D-x = 1.332 g cm(-3) Compound (2) crystallizes in the orthorhombic space group Pbca with a = 19.580(3), b = 9.416(2), c = 27.801(2) Angstrom, V = 5125.5(6) Angstrom(3), Z = 8 and D-x = 1.451g cm(-3) In the crystal structure of the free Schiff base ligand (1), the existence of a strong intramolecular N-H...O hydrogen bond INO = 2.572(4), N-H = 0.90(4), H...O = 1.759(4) Angstrom, N-H...O = 149.6(3)degrees] is observed. The C-N amine bond and C-N-C bond angle are 1.345(4)Angstrom and 124.4(3)degrees, respectively. The C3 = O1 and C4 = C5 bond lengths [1.274(4) and 1.351(5) Angstrom] are shortened by the pronounced quinoidal effect. In solution, compound (1) is in tautomeric equilibria (phenol-imine, O-H ... N keto-amine, O ... H-N forms), as supported by H-1 NMR and UV-visible data. In the crystal structure of the Zn(II) complex (2), zinc atom has a distorted tetrahedral coordination. One of the pyridine N atom of the ligands is in close contact with the Zn(II) atom [Zn1 ... N4 = 2.864(5) Angstrom].It is interesting that the C-N amine bond [1.345(4) Angstrom] in compound (1) changes to the imine bond [1.27(5) Angstrom] in the Zn(TI) complex (2). (C) 2000 Elsevier Science B.V. All rights reserved

Phosphorus-nitrogen compounds. Part VI. Aminolysis of octachlorocyclotetraphosphazatetraene and the crystal structure of 2-trans-6-bis(n-propylamino)-2,4,4,6,8,8-hexakis-tert-butylaminocyclo-2 lambda(5), 4 lambda(5), 6 lambda(5), 8 lambda(5)-tetraphosphazatetraene

Hokelek, Tuncer/0000-0002-8602-4382WOS: 000186239600017The reactions of 2-trans-6-N4P4(NBPrn)(2)CI6 (2), which was obtained from N4P4Cl8 (1) and n-propylamine, with pyrrolidine and t-butylamine in different solvents have been studied. Compound (2) gave two different products, namely monocyclic (3 and 5) and bicyclic (4 and 6) phosphazenes. Compounds (2-6) have been characterized by elemental analysis, IR, H-1-, C-13-, P-31 NMR, HETCOR and MS and the structure of compound (5) has been examined crystallographically. The bicyclic phosphazene (6) is the first exciting example of bicyclic phosphazenes containing chlorine atoms, in the literature. The formation mechanisms of bicyclic phosphazenes are re-considered by taking into account the synthesis of compound (6), which contains three stereogenic phosphorus atoms. Compound (5) crystallizes in the monocyclic space group P2(1) In with a = 13.974(2), b = 17.836(5), and c = 18.683(4) Angstrom, beta = 98.50(1)degrees, V = 4605.4(2) Angstrom(3), Z = 4 and D-x = 1.051 g cm(-3). It consists of a non-centrosymmetric, nonplanar phosphazene ring in a saddle conformation, with two n-propylamino (in 2-trans-6 positions) and six bulky t-butylamino side groups. The bulky substituents are instrumental in determining the molecular geometry. (C) 2003 Elsevier B.V. All rights reserved