A One‐Pot Synthesis of N‐Aryl‐2‐Oxazolidinones and Cyclic Urethanes by the Lewis Base Catalyzed Fixation of Carbon Dioxide into Anilines and Bromoalkanes

The multicomponent assembly of pharmaceutically relevant N‐aryl‐oxazolidinones through the direct insertion of carbon dioxide into readily available anilines and dibromoalkanes is described. The addition of catalytic amounts of an organosuperbase such as Barton's base enables this transformation to proceed with high yields and exquisite substrate functional‐group tolerance under ambient CO₂ pressure and mild temperature. This report also provides the first proof‐of‐principle for the single‐operation synthesis of elusive seven‐membered ring cyclic urethanes.     

Stochastic programs without duality gaps

This paper studies dynamic stochastic optimization problems parameterized by a random variable. Such problems arise in many applications in operations research and mathematical finance. We give sufficient conditions for the existence of solutions and the absence of a duality gap. Our proof uses extended dynamic programming equations, whose validity is established under new relaxed conditions that generalize certain no-arbitrage conditions from mathematical finance.     

Fast gas chromatography-negative-ion chemical ionization mass spectrometry with microscale volume sample preparation for the determination of benzodiazepines and alpha-hydroxy metabolites, zaleplon and zopiclone in whole blood

Fast gas chromatography/negative-ion chemical ionization mass spectrometric (GC/NICI-MS) assay combined with rapid and nonlaborious sample preparation is presented for the simultaneous determination of benzodiazepines and alpha-hydroxy metabolites, zaleplon and zopiclone in whole blood. The compounds were extracted from 100 microl of whole blood by simultaneous multitube, microscale liquid-liquid extraction (LLE) and derivatized by N-methyl-N-(tert-butyldimethylsilyl)trifluoroacetamide (MTBSTFA), without the need for the time-consuming concentration stage. In the analytical separation, various parameters of fast GC/NICI-MS were applied, e.g. the use of hydrogen as a GC carrier gas, a high carrier gas velocity, a small film thickness of the analytical column, fast MS data acquisition, fast temperature ramping, and high initial and final temperatures of GC column. Sensitive identification, screening and quantitation of 18 compounds of interest were achieved in chromatographic separation in only 4.40 min. Accurate and reproducible results were obtained by using five different and carefully selected deuterated analogues on the basis of the chemical properties of the target analytes. Nevertheless, for alpha-OH-midazolam, and for bromazepam and flunitrazepam at low concentrations, the results can be considered only semiquantitative on the basis of the validation data. The extraction efficiencies ranged from 74.3 to 105.7% and the limits of quantitation (LOQ) from 1 to 100 ng ml(-1). Rapid sample preparation and fast chromatographic separation allowed cost-efficient, reliable and high sample-throughput analyses with a low amount of manual work. The method was fully validated and accredited according to EN ISO/IEC 17025 standards and is applicable for sensitive, reliable and quantitative determination of benzodiazepines, zaleplon and zopiclone, e.g. in clinical and forensic toxicology.     

Low-Power Application-Specific Processor for FFT Computations

In this paper, a processor architecture tailored for radix-4 and mixed-radix FFT computations is described. The processor has native support for power-of-two transform sizes. Several optimizations have been used to improve the energy-efficiency of the processor and experiments show that a programmable solution can possess energy-efficiency comparable to fixed-function ASICs.     

The effect of palladium dispersion and promoters on lactose oxidation kinetics

Lactose oxidation was investigated at 70 °C and at pH 8 using oxygen as an oxidant over a comprehensive set of commercially available mono- and multi-metallic as well as promoted Pd catalysts with active carbon, alumina and calcium carbonate as catalyst supports. An optimum cluster size of 6–10 nm resulted in the highest initial turnover frequencies. High conversion levels above 90% were achieved on Pd/C catalyst, as well as over Pd/Al₂O₃ and (Pd–Pb)/CaCO₃, whereas (Pd–V)/C catalyst gave only 30% conversion after 200 min. The latter catalyst was relatively inactive due to its high support acidity and profound deactivation during oxidation. Besides the main oxidation product, lactobionic acid, also, lactulose was generated as a result of lactose isomerisation under alkaline conditions. The electrochemical potentials of the catalysts were measured during lactose oxidation. The main result of these measurements was that, when the electrochemical potential of the catalyst increased very quickly, its oxidation activity was low due to metal over-oxidation. The selectivities to the desired product, lactobionic acid, were relatively high, above 80% for most of the catalysts, except for (Pd–V)/C. Furthermore, the selectivity to the lactobionic acid decreased with increasing metal dispersion, thus, indicating that the optimum metal particle sizes for producing high amounts of lactobionic acid is above 3 nm.     

Electrical manipulation and measurement of spin properties of quantum spin Hall edge states

We study the effects of a gate-controlled Rashba spin-orbit coupling to quantum spin Hall edge states in HgTe quantum wells. A uniform Rashba coupling can be employed in tuning the spin orientation of the edge states while preserving the time-reversal symmetry. We introduce a sample geometry where the Rashba coupling can be used in probing helicity by purely electrical means without requiring spin detection, application of magnetic materials or magnetic fields. In the considered setup a tilt of the spin orientation with respect to the normal of the sample leads to a reduction in the two-terminal conductance with current-voltage characteristics and temperature dependence typical of Luttinger liquid constrictions.     

Design Methodology for Offloading Software Executions to FPGA

Field programmable gate array (FPGA) is a flexible solution for offloading part of the computations from a processor. In particular, it can be used to accelerate an execution of a computationally heavy part of the software application, e.g., in DSP, where small kernels are repeated often. Since an application code for a processor is a software, a design methodology is needed to convert the code into a hardware implementation, applicable to the FPGA. In this paper, we propose a design method, which uses the Transport Triggered Architecture (TTA) processor template and the TTA-based Co-design Environment toolset to automate the design process. With software as a starting point, we generate a RTL implementation of an application-specific TTA processor together with the hardware/software interfaces required to offload computations from the system main processor. To exemplify how the integration of the customized TTA with a new platform could look like, we describe a process of developing required interfaces from a scratch. Finally, we present how to take advantage of the scalability of the TTA processor to target platform and application-specific requirements.     

Graph-distance convergence and uniform local boundedness of monotone mappings

In this article we study graph-distance convergence of monotone operators. First, we prove a property that has been an open problem up to now: the limit of a sequence of graph-distance convergent maximal monotone operators in a Hilbert space is a maximal monotone operator. Next, we show that a sequence of maximal monotone operators converging in the same sense in a reflexive Banach space is uniformly locally bounded around any point from the interior of the domain of the limit mapping. The result is an extension of a similar one from finite dimensions. As an application we give a simplified condition for the stability (under graph-distance convergence) of the sum of maximal monotone mappings in Hilbert spaces.

     

Application of enriched stable 196Hg isotope for monitoring the stability of total mercury in water samples

A novel tool for the investigation of stability of total mercury in water samples is presented. The study focuses on the application of enriched ¹⁹⁶Hg stable isotopic reagent for the stability studies. Natural abundance of ¹⁹⁶Hg in water samples is only 0.15%. Thus, the use of the ¹⁹⁶Hg isotope spike represents a major advantage, when it can be assumed that all the measured isotope is the same as is accurately added by the analyst, and the change in its mass concentration can be followed simply and reliably. Tests were carried out with industrial waste water and two type of the natural water. Cold vapour (CV) inductively coupled plasma mass spectrometer (ICP-MS) technique was applied for the mercury measurements. Monitoring was continued for approximately 100 days. It is commonly advised that the measurement for total mercury in water samples should be carried out within 14 days. In this study the samples were observed to be stable for more than three months, if they were stored at a temperature of 4–6°C. The results of this stability study were in line with the guidance presented in EPA standard 1631. However, the samples were noticed to be stable for a much longer time than is presented in the standard method ISO 17852.