Simultaneous high-performance liquid chromatographic determination of antazoline phosphate and tetrahydrozoline hydrochloride in ophthalmic solution

A method for the determination of 2-[(N-phenyl)benzylaminomethyl]-2-imidazoline X H3PO4 (antazoline phosphate) and 2-(1,2,3,4-tetrahydro-1-naphthyl)-2-imidazoline X HCl (tetrahydrozoline hydrochloride) in ophthalmic solution is described. The pharmaceutical preparation is analysed directly by reversed-phase ion-pair high-performance liquid chromatography and the method is very rapid, selective and simple.     

A two dimensional Lagrangian model with extended supersymmetry and infinitely many constants of motion

The reduction of the supersymmetric gradedSU(2|1) /S(U ₂×U ₁) -model is discussed. If no extra constraint is imposed, one gets a set of two coupled equations (involving two scalar superfields) which generalizes the supersymmetric sine-Gordon equation. It is shown that these equations, which can be derived by a supersymmetric Lagrangian, reproduce in the bosonic limit the reduced version of theO(4) -model (Pohlmeyer, Lund Regge, Getmanov model). Moreover the associate linear set and an infinite set of local conservation laws for this new supersymmetric model are exhibited. It turns out that, beyond the spinorial charge which generates the supersymmetry transformations, another unexpected spinorial charge is conserved; then the model appears to be invariant underN=2 extended supersymmetry.     

Polymer supported calixarene derivative useful for solid-phase synthesis application

A calix[4]arene derivative has been anchored to carboxyl CPG and TentaGel supports by an easily cleavable ester bond and DMT groups allow a simple loading evaluation via UV-vis spectroscopy. The loading of the calixarene on TentaGel resin has also been estimated by HR-MAS NMR experiments. The potential of the polymer supported calixarenes (9 and 10) in solid phase synthesis has been tested by condensation of four thymine nucleotide units onto the upper rim of the calix[4]arene skeleton.     

An Electrostatic Charge Partitioning Model for the Dissociation of Protein Complexes in the Gas Phase

Electrosprayed multi-protein complexes can be dissociated by collisional activation in the gas phase. Typically, these processes follow a mechanism whereby a single subunit gets ejected with a disproportionately high amount of charge relative to its mass. This asymmetric behavior suggests that the departing subunit undergoes some degree of unfolding prior to being separated from the residual complex. These structural changes occur concomitantly with charge (proton) transfer towards the subunit that is being unraveled. Charge accumulation takes place up to the point where the subunit loses physical contact with the residual complex. This work develops a simple electrostatic model for studying the relationship between conformational changes and charge enrichment during collisional activation. Folded subunits are described as spheres that carry continuum surface charge. The unfolded chain is envisioned as random coil bead string. Simulations are guided by the principle that the system will adopt the charge configuration with the lowest potential energy for any backbone conformation. A finite-difference gradient algorithm is used to determine the charge on each subunit throughout the dissociation process. Both dimeric and tetrameric protein complexes are investigated. The model reproduces the occurrence of asymmetric charge partitioning for dissociation events that are preceded by subunit unfolding. Quantitative comparisons of experimental MS/MS data with model predictions yield estimates of the structural changes that occur during collisional activation. Our findings suggest that subunit separation can occur over a wide range of scission point structures that correspond to different degrees of unfolding.     

Experimental evidence of mounting grooves and serration patterns on fin lines characteristics

In this paper, the mounting grooves and serration patterns of fin line circuits are investigated experimentally. Our measurements show that the short-circuit ended mounting grooves degrade seriously the insertion loss of fin lines at the low frequencies of the band. The open ended mounting grooves are found better for fin lines applications and measurements. An improvement of 0.7 dB is observed over the whole band, when the serration patterns of the fin line are placed into the open-ended mounting grooves. These results can be used for measuring the losses and for designing transitions or other fin line circuits.     

VII. Difficulties in fixing the gauge in non-Abelian gauge theories

Some problems arising from the use of the Coulomb gauge in SU(2) Yang-Mills theory are discussed. It is shown that: i) the transversality condition does not fix the gauge uniquely (Gribov ambiguity); ii) there exist physical configurations that cannot be described by a continuous A_μ in the Coulomb gauge.     

Glycoclusters presenting lactose on calix[4]arene cores display trypanocidal activity

A new series of water-soluble tetravalent glycoclusters incorporating β-lactosyl residues attached to a central calix[4]arene core was synthesised using azide-alkyne Cu(I)-catalysed cycloaddition (‘click chemistry’). Carbohydrate moieties were attached either to the upper or lower rim of rigid cone-shaped or partial cone macrocycles via 14-21 atom spacer arms. The glycoclusters with a C₄-symmetrical arrangement of β-lactosyl residues showed trypanocidal activity, with one of them showing comparable activity to established anti-trypanosomal drug benznidazole in in vitro anti-parasite assays.