Lagrange Duality in Set Optimization

Based on the complete-lattice approach, a new Lagrangian type duality theory for set-valued optimization problems is presented. In contrast to previous approaches, set-valued versions for the known scalar formulas involving infimum and supremum are obtained. In particular, a strong duality theorem, which includes the existence of the dual solution, is given under very weak assumptions: The ordering cone may have an empty interior or may not be pointed. “Saddle sets” replace the usual notion of saddle points for the Lagrangian, and this concept is proven to be sufficient to show the equivalence between the existence of primal/dual solutions and strong duality on the one hand, and the existence of a saddle set for the Lagrangian on the other hand. Applications to set-valued risk measures are indicated.     

An optimization technique based on a vector autoregression model with state space representation: application to Ukrainian cargo transport data

This paper proposes to forecast indicators of the Ukrainian cargo transport system, taking into account their relations with macroeconomic indicators. Increased forecast accuracy at a priori information uncertainty is attained through an optimization technique, starting with a Vector Autoregression (VAR) model of observed multiple time series, its state space representation and subsequent adaptive filtering. The adaptive filter, earlier proposed by the authors, minimizes forecasting errors. Under an optimization criterion, the information divergence of Kullback–Leibler between probability distributions of real values and their estimations is established. The main advantage of the proposed technique is connected with the opportunity to estimate future values of multiple time series even in presence of structural breaks (describing the changes of the status ‘before crisis’ / ‘after crisis’). The observations are available from 2003:1–2011:12, the analysis is performed for the period 2003:1–2011:9. In-sample forecasting of multiple time series of cargo volumes transferred by different transport modes and two macro indicators is compared with the forecast based on a VAR model. In-sample forecast is realized for the last three months 2011:10–2011:12.     

Study by focused shadowgraphy of the effect of laser irradiance on laser-induced plasma formation and ablation rate in various gases

The influence of laser irradiance on the extent of laser-sample coupling at 1064 nm was investigated in argon, air and helium at atmospheric pressure. Focused shadowgraphy measurements allowed the observation of laser–matter interaction at the nanosecond timescale and to visualize different behaviors in argon, air and helium atmospheres. It was established using shadowgraphy and laser drilling experiments that the growth of ablation rate with laser irradiance changes drastically depending on the irradiance range considered. In addition, laser-induced gas breakdown and laser-supported detonation processes, which have different origins but may both lead to decreased coupling via plasma shielding, could clearly be distinguished.     

The assembly-inducing laulimalide/peloruside a binding site on tubulin: molecular modeling and biochemical studies with [³H]peloruside A

We used synthetic peloruside A for the commercial preparation of [3H]peloruside A. The radiolabeled compound bound to preformed tubulin polymer in amounts stoichiometric with the polymer's tubulin content, with an apparent K(d) value of 0.35 μM. A less active peloruside A analogue, (11-R)-peloruside A and laulimalide acted as competitive inhibitors of the binding of the [3H]peloruside A, with apparent K(i) values of 9.3 and 0.25 μM, respectively. Paclitaxel, epothilone B, and discodermolide had essentially no ability to inhibit [3H]peloruside A binding, confirming that these compounds bind to a different site on tubulin polymer. We modeled both laulimalide and peloruside A into the binding site on β-tubulin that was identified by Huzil et al. (J. Mol. Biol. 2008, 378, 1016-1030), but our model provides a more reasonable structural basis for the protein-ligand interaction. There is a more complete desolvation of the peloruside A ligand and a greater array of favorable hydrophobic and electrostatic interactions exhibited by peloruside A at its β-tubulin binding site. In addition, the protein architecture in our peloruside A binding model was suitable for binding laulimalide. With the generation of both laulimalide and peloruside A binding models, it was possible to delineate the structural basis for the greater activity of laulimalide relative to peloruside A and to rationalize the known structure-activity relationship data for both compounds.     

Extended equivariant Picard complexes and homogeneous spaces

Let k be a field of characteristic 0 and let [`(k)] \bar{k} be a fixed algebraic closure of k. Let X be a smooth geometrically integral k-variety; we set [`(X)] = X ×_k[`(k)] \bar{X} = X{ \times_k}\bar{k} and denote by [`(X)] \bar{X} . In [BvH2] we defined the extended Picard complex of X as the complex of Gal( [`(k)]

Zampanolide, a potent new microtubule-stabilizing agent, covalently reacts with the taxane luminal site in tubulin α,β-heterodimers and microtubules

Zampanolide and its less active analog dactylolide compete with paclitaxel for binding to microtubules and represent a new class of microtubule-stabilizing agent (MSA). Mass spectrometry demonstrated that the mechanism of action of both compounds involved covalent binding to β-tubulin at residues N228 and H229 in the taxane site of the microtubule. Alkylation of N228 and H229 was also detected in α,β-tubulin dimers. However, unlike cyclostreptin, the other known MSA that alkylates β-tubulin, zampanolide was a strong MSA. Modeling the structure of the adducts, using the NMR-derived dactylolide conformation, indicated that the stabilizing activity of zampanolide is likely due to interactions with the M-loop. Our results strongly support the existence of the luminal taxane site of microtubules in tubulin dimers and suggest that microtubule nucleation induction by MSAs may proceed through an allosteric mechanism.     

Simultaneous passively Q-switched dual-wavelength solid-state laser working at 1065 and 1066 nm

A passively Q-switched dual-wavelength solid-state laser is presented. The two wavelengths are emitted by two different crystals in order to avoid gain competition, and the synchronization between the pulses is obtained by external triggering of the saturable absorber. Sum frequency mixing is demonstrated, proving the interest of this source for terahertz generation in the 0.3-0.4 THz range through difference frequency generation.     

Structure of dense liquid water by neutron scattering to 6.5 GPa and 670 K

We present a neutron diffraction study of liquid water to 6.5 GPa and 670 K. From the measured structure factors we determine radial and angular distributions. It is shown that with increasing density water approaches a local structure common to a simple liquid while distorting only a little the tetrahedral first-neighbor coordination imposed by hydrogen bonds that remain intact.     

Electrochemical properties of silver–copper alloy microelectrodes for use in voltammetric field apparatus

Microelectrodes of silver–copper alloys have been evaluated for use in voltammetric analyses. Increased overpotential towards the hydrogen overvoltage reaction (HER) was found as a function of increased copper content in the silver. A study of oxidizing products by cyclic voltammetry (CV) in NaOH solution showed ten anodic and eight cathodic peaks which are described in the present paper. The behaviour of these alloy electrodes is somewhere between pure silver and pure copper electrodes. Differential pulse anodic stripping voltammetry (DPASV) was used to measure zinc, cadmium and lead in ultrapure water only (18 MΩcm), and good linearity was found for all metals (r ²=0.998) in the range of 0.5 to 5 ppb with a 600- to 1,200-s plating time. It was additionally found that cadmium and lead were better separated on the alloy electrodes compared to pure silver electrodes. Measurements of nickel were carried out on alloy electrodes by use of adsorptive differential pulse cathodic stripping voltammetry (Ad-DPCSV), and good linearity (r ²=1.000) was found in the range from 0.5 to 5 ppb with an adsorption time of 120 s. The alloy electrodes were also found to be sensitive to nitrate, and good linearity (r ²=0.997) was found in the range from 1 mg L⁻¹ to 100 mg L⁻¹ using differential pulse voltammetry (DPV) scanning from −450 mV to −1,500 mV. Addition of nitrate in ultrapure water afforded two different peaks related to the successive reductions of nitrate and nitrite. In ammonium buffer solution (pH 8.6) only one peak resulting from reduction of nitrate was observed. Furthermore, the use of alloy electrodes containing 17% Cu was tested in real samples, by installing it in a voltammetric system for monitoring of zinc and lead in a polluted river, the river Deûle, near the town of Douai in northern France. Results were found to be in agreement with parallel measurements carried out by ICP-MS.     

Reduction of nonspecific protein binding on surface plasmon resonance biosensors

Reduction of the nonspecific serum protein adsorption on a gold surface to levels low enough to allow the detection of biomarkers in complex media has been achieved using the N-hydroxysuccinimide (NHS) ester of 16-mercaptohexadecanoic acid. Carboxymethylated dextran (CM dextran), which is widely used, nonspecifically adsorbs enough proteins to mask the signal from target biomarkers in complex solutions such as serum or blood. The use of short-chain thiols greatly reduces the amount of nonspecific protein adsorption. Mixed layers of 11-mercaptoundecanoic acid or the NHS ester of 11-mercaptoundecanoic acid mixed layers with either 11-mercaptoundecanol or undecanethiol, and 16-mercaptohexadecanoic acid or the NHS ester of 16-mercaptohexadecanoic acid with hexadecanethiol, were also investigated for nonspecific protein binding properties as well as for biomarker signal response. The NHS ester of 16-mercaptohexadecanoic acid exhibits the largest signal for the biomarker myoglobin (including CM dextran) while offering a significantly diminished amount of nonspecific binding. The sensor has also been shown to detect interleukin-6 in cell culture media containing protein concentrations of at least 4 mg/mL.