Striking medium effects on the kinetics of decomposition of macrocyclic Cu2+ complexes: Additional considerations to be taken when designing Copper-64 radiopharmaceuticals

The kinetics of decomposition of a macrocyclic Cu²⁺ complex is strongly dependent on the anions in solution. In particular, chloride anions accelerate significantly the decomposition process, even out of the stopped-flow time scale. Given the different Cl^? concentrations in biological media, the possibility of changes in the decomposition kinetics must be considered when designing ⁶⁴Cu radiopharmaceuticals.     

Optical Pliers: Micrometer-Scale,Light-Driven Tools Grown on Optical Fibers

The ability to grip and handle small objects, from sub-millimeter electronic components to single-micrometer living cells, is vital for numerous ever-shrinking technologies. Mechanical grippers, powered by electric, pneumatic, hydraulic or piezoelectric servos, are well suited for the job at larger scales, but their complexity and need for force transmission prevent their miniaturization and remote control in tight spaces. Using liquid crystal elastomer microstructures that can change shape quickly and reversibly in response to light, a light-powered gripping tool—optical pliers—is built by growing two bending jaws on the tips of optical fibers. By delivering UV light to trigger polymerization via a micrometer-size fiber core, structures of similar size can be made without resorting to any microfabrication technology, such as laser photolithography. The tool is operated using visible light energy supplied through the fibers, with no force transmission. The elastomer growth technique readily offers micrometer-scale, remotely controlled functional structures with different modes of actuation as building blocks for the microtoolbox.     

Effective asymmetric XML compression

The innate verbosity of the extensible markup language (XML) remains one of its main weaknesses, especially when large documents are concerned. This problem can be solved with the aid of dedicated XML compression algorithms. In this work, we describe XML word‐replacing transform (XML‐WRT), a fast and fully reversible XML transform, which, when combined with generally used LZ77‐style compression algorithms, allows to attain high compression ratios, comparable to those achieved by the current state‐of‐the‐art XML compressors. The resulting compression scheme is asymmetric in the sense that its decoder is much faster than the coder. This is a desirable practical property, as in many XML applications data are read much more often than written. The key features of the transform are dictionary‐based encoding of both document structure and content, separation of different content types into multiple streams, and dedicated encoding of specific patterns, including numbers and dates. The test results show that the proposed transform improves the XML compression efficiency of general‐purpose compressors on average by 35% in case of gzip, and 17% in case of LZMA. Compared with the current state‐of‐the‐art SCMPPM algorithm, XML‐WRT with LZMA attains over 2% better compression ratio, while being 55% faster. Copyright © 2007 John Wiley & Sons, Ltd.     

Improved Distributed Algorithms for SCC Decomposition

We study and improve the OBF technique [Barnat, J. and P.Moravec, Parallel algorithms for finding SCCs in implicitly given graphs, in: Proceedings of the 5th International Workshop on Parallel and Distributed Methods in Verification (PDMC 2006), LNCS (2007)], which was used in distributed algorithms for the decomposition of a partitioned graph into its strongly connected components. In particular, we introduce a recursive variant of OBF and experimentally evaluate several different implementations of it that vary in the degree of parallelism. For the evaluation we used synthetic graphs with a few large components and graphs with many small components. We also experimented with graphs that arise as state spaces in real model checking applications. The experimental results are compared with that of other successful SCC decomposition techniques [Orzan, S., “On Distributed Verification and Verified Distribution,” Ph.D. thesis, Free University of Amsterdam (2004); Fleischer, L.K., B. Hendrickson and A. Pinar, On identifying strongly connected components in parallel, in: Parallel and Distributed Processing, IPDPS Workshops, Lecture Notes in Computer Science 1800, 2000, pp. 505–511].     

Microfabricated devices: A new sample introduction approach to mass spectrometry

Instrument miniaturization is one way of addressing the issues of sensitivity, speed, throughput, and cost of analysis in DNA diagnostics, proteomics, and related biotechnology areas. Microfluidics is of special interest for handling very small sample amounts, with minimal concerns related to sample loss and cross-contamination, problems typical for standard fluidic manipulations. Furthermore, the small footprint of these microfabricated structures leads to instrument designs suitable for high-density, parallel sample processing, and high-throughput analyses. In addition to miniaturized systems designed with optical or electrochemical detection, microfluidic devices interfaced to mass spectrometry have also been demonstrated. Instruments for automated sample infusion analysis are now commercially available, and microdevices utilizing chromatographic or capillary electrophoresis separation techniques are under development. This review aims at documenting the technologies and applications of microfluidic mass spectrometry for the analysis of proteomic samples.     

Collisions of electrons with hydrogen atoms II. Low-energy program using the method of the exterior complex scaling

While collisions of electrons with hydrogen atoms pose a well studied and in some sense closed problem, there is still no free computer code ready for “production use”, that would enable applied researchers to generate necessary data for arbitrary impact energies and scattering transitions directly if absent in on-line scattering databases. This is the second article on the Hex program package, which describes a new computer code that is, with a little setup, capable of solving the scattering equations for energies ranging from a fraction of the ionization threshold to approximately 100 eV or more, depending on the available computational resources. The program implements the exterior complex scaling method in the B-spline basis.     

Looking back at dense linear algebra software

Over the years, computational physics and chemistry served as an ongoing source of problems that demanded the ever increasing performance from hardware as well as the software that ran on top of it. Most of these problems could be translated into solutions for systems of linear equations: the very topic of numerical linear algebra. Seemingly then, a set of efficient linear solvers could be solving important scientific problems for years to come. We argue that dramatic changes in hardware designs precipitated by the shifting nature of the marketplace of computer hardware had a continuous effect on the software for numerical linear algebra. The extraction of high percentages of peak performance continues to require adaptation of software. If the past history of this adaptive nature of linear algebra software is any guide then the future theme will feature changes as well–changes aimed at harnessing the incredible advances of the evolving hardware infrastructure.     

Ternary polymer electrolytes with 1-methylimidazole based ionic liquids and aprotic solvents

New polymer gel electrolytes containing ionic liquids were developed for modern chemical power sources—supercapacitors and lithium-ion batteries. Ternary systems polymer-ionic liquid-aprotic solvent as well as materials containing also lithium salts (LiClO₄ or LiPF₆) were prepared by direct, thermally initiated polymerisation. Poly(2-ethoxyethyl methacrylate) PEOEMA was combined with various ionic liquids based on 1-methylimidazole. Only 1-butyl-3-methylimidazolium hexafluorophosphate BMIPF₆ formed a homogenous and slightly translucent polymer electrolyte, where aprotic solvents—propylene carbonate and ethylene carbonates were used as plasticisers. Materials were studied using the electrochemical and thermogravimetric methods and exhibit high ionic conductivity up to 0.94 mS cm⁻¹ at 25 °C together with high electrochemical stability: the accessible potential window on the glassy carbon was found ca. 4.3 V. Prepared non-volatile materials are long-term and thermally stable up to 150 °C.     

Solving the 2-Disjoint Connected Subgraphs Problem Faster than 2 n

The 2-Disjoint Connected Subgraphs problem, given a graph along with two disjoint sets of terminals Z ₁,Z ₂, asks whether it is possible to find disjoint sets A ₁,A ₂, such that Z ₁?A ₁, Z ₂?A ₂ and A ₁,A ₂ induce connected subgraphs. While the naive algorithm runs in O(2 ⁿ n ^O(1)) time, solutions with complexity of form O((2?ε) ⁿ ) have been found only for special graph classes (van ’t Hof et al. in Theor. Comput. Sci. 410(47–49):4834–4843, 2009; Paulusma and van Rooij in Theor. Comput. Sci. 412(48):6761–6769, 2011). In this paper we present an O(1.933 ⁿ ) algorithm for 2-Disjoint Connected Subgraphs in general case, thus breaking the 2 ⁿ barrier. As a counterpoise of this result we show that if we parameterize the problem by the number of non-terminal vertices, it is hard both to speed up the brute-force approach and to find a polynomial kernel.