Computational thermal and kinetic analysis

The complexation of β-lactam antibiotics, amoxicillin (AMPC), ampicillin (ABPC) and benzylpenicillin (PCG), with 2-hydroxypropyl-β-cyclodextrin (HPCD) was studied at various pH values using microcalorimetry, ¹H NMR spectroscopy, and molecular dynamic simulation. In the strong acid solution, two different types of inclusion complex with a 1:1 stoichiometry, Complex I with a phenyl ring of β-lactam antibiotics penetrated into the cavity of HPCD and Complex II with a penam included in the cavity, were formed by hydrophobic interaction, and Complex II was more stable than Complex I. In aqueous solution at pH≥4.5, only Complex I was formed, where the penam of PCG was more deeply penetrated into the cavity to keep it stable than those of AMPC and ABPC. The charged carboxyl-group on the penam was less affinity to form Complex II.     

Diffusion coefficient and shear viscosity of rigid water models

We report the diffusion coefficient and viscosity of popular rigid water models: two non-polarizable ones (SPC/E with three sites, and TIP4P/2005 with four sites) and a polarizable one (Dang-Chang, four sites). We exploit the dependence of the diffusion coefficient on the system size (Yeh and Hummer 2004 J. Phys. Chem. B 108 15873) to obtain the size-independent value. This also provides an estimate of the viscosity of all water models, which we compare to the Green-Kubo result. In all cases, a good agreement is found. The TIP4P/2005 model is in better agreement with the experimental data for both diffusion and viscosity. The SPC/E and Dang-Chang models overestimate the diffusion coefficient and underestimate the viscosity.     

Bifibrations and Weak Factorisation Systems

We review a theorem of A. Roig about Quillen model structures on Grothendieck bifibrations and observe that it contains a gap. We reformulate one of its assumptions in order to validate it. As an application to the new version, we introduce the fibred model structure on the category of small categories enriched in a suitable monoidal model category.     

Carotid plaque high-resolution MRI at 3 T: evaluation of a new imaging score for symptomatic plaque assessment

Purpose

To assess the sensitivity and specificity of intra-plaque hemorrhage (IPH), large lipid-rich necrotic core (LR-NC) and ulceration or cap rupture (UCR) for symptomatic carotid plaque characterization and to evaluate a new imaging score [Hemorrhage, Ulceration or cap rupture, Lipid-rich necrotic Core (HULC) score based on the sum of presence/absence of IPH, UCR and LR-NC; range 0–3] for assessment of recently symptomatic carotid plaques.

Material and methods

Twenty-seven recently symptomatic (< 8 weeks) and 36 asymptomatic patients with a carotid plaque thicker than 2 mm were prospectively imaged on a 3-T magnetic resonance (MR) system using high-resolution, multi-contrast MR sequences. Prior to analysis, all images were reviewed to assess image quality of each sequence. Sensitivity and specificity of IPH, LR-NC, UCR and HULC scores were calculated.

Results

Fifty-one patients were analyzed (26 symptomatic carotids and 67 asymptomatic carotids) after exclusion of studies with poor image quality. Sensitivity and specificity for symptomatic carotid plaque was, respectively, 46.1% and 97% for IPH, 84.6% and 73.1% for UCR and 80.7% and 76.1% for LR-NC. A HULC score of 2 or more showed a sensitivity of 73% and a specificity of 92.5%.

Conclusion

At 3 T, intra-plaque hemorrhage is the most specific criterion to characterize symptomatic carotid plaque. The HULC score offers the best compromise between sensitivity and specificity.     

Control of quasiparticle self-fluctuations in a CuCl crystal

A theory is developed for regular and chaotic self fluctuations in crystal CuCl for a ring resonator geometry. A system of nonlinear differential equations is derived for the dynamic evolution of coherent excitons, photons, and biexcitons. It is shown that, in the unstable portions of the optical bistability curves, nonlinear periodic and chaotic self fluctuations can develop with the creation of limit cycles and strange attractors in the phase space of the system. A computer simulation is used to determine the parameters for which reliable switching takes place in the system and the parameter ranges are found within which the system undergoes a transition from strange attractor to limit cycle. The possibility of experimentally observing the phenomena studied here is discussed. Fiz. Tverd. Tela (St. Petersburg) 41, 1939–1943 (November 1999)     

Active control laws for aeroelasticity

The objective of this paper is to describe a methodology to design control laws in the context of a computational aeroelasticity environment. The technical approach involves employing a systems identification technique to develop an explicit state-space model for control law design from the output of a computational aeroelasticity code. As a control law design techniques, the standard LQG technique is employed. The computational aeroelasticity code is modified to accept control laws and perform closed-loop simulations. Numerical results for flutter suppression of the BACT wind-tunnel model are given. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

On the boundary value problem of water infiltration into a nonhomogeneous unsaturated soil

The paper deals with the resolution of an optimization problem related to the nonlinear water infiltration into a stratified soil with two layers, for the hydraulic model introduced by Broadbridge and White.     

Using Entropy to Evaluate the Impact of Monetary Policy Shocks on Financial Networks

We analyze the changes in the financial network built using the Dow Jones Industrial Average components following monetary policy shocks. Monetary policy shocks are measured through unexpected changes in the federal funds rate in the United States. We determine the changes in the financial networks using singular value decomposition entropy and von Neumann entropy. The results indicate that unexpected positive shocks in monetary policy shocks lead to lower entropy. The results are robust to varying the window size used to construct financial networks, though they also depend on the type of entropy used.     

Synthesis,Characterisation, and in vitro Cytotoxic Activity of Dithiocarbamato Glycoconjugate Half-Sandwich Ruthenium and Osmium Complexes

The synthesis by transmetallation and in-depth characterisation by IR spectroscopy of five half-sandwich ruthenium and osmium dithiocarbamato isonipecotamide glycoconjugate complexes are presented herein. The evaluation of their in vitro cytotoxicity and of the zinc precursors’ in vitro cytotoxicity towards ovarian cancer (A2780 and A2780cisR) and normal prostate (PNT2) cells is reported. While the cytotoxicity of the compounds is rather limited, some selectivity is observed.     

Dual action of Impurities in Crystal Growth from Solutions

A dual action of impurities becomes evidently in growth kinetic of prismatic faces of KDP. At higher supersaturation two-dimensional nucleation mechanism due to impurities prevails. At smaller supersaturation the blocking effect of the steps created by the dislocation mechanism of growth become efficient. The limit of the “dead” growth zone depending on the impurity's concentration and the solution pH is a result of this last effect and agrees with the Cabrera-Vermilyea mechanism.