New Red‐Emitting Tetrazine‐Phenoxazine Fluorogenic Labels for Live‐Cell Intracellular Bioorthogonal Labeling Schemes

The synthesis of a set of tetrazine‐bearing fluorogenic dyes suitable for intracellular labeling of proteins in live cells is presented. The red excitability and emission properties ensure minimal autofluorescence, while through‐bond energy‐transfer‐based fluorogenicity reduces nonspecific background fluorescence of unreacted dyes. The tetrazine motif efficiently quenches fluorescence of the phenoxazine core, which can be selectively turned on chemically upon bioorthogonal inverse‐electron‐demand Diels–Alder reaction with proteins modified genetically with strained trans‐cyclooctenes.     

Influence of the preparation method on the morphology of templated NiCo<Subscript>2</Subscript>O<Subscript>4</Subscript> spinel

The synthesis of NiCo₂O₄ spinel by several nanocasting strategies (i.e., multi-step nanocasting, one-step nanocasting and soft-templating), in which nickel and cobalt nitrates are used as precursors and Pluronic P123 as surfactant, is explored. First, in the multi-step nanocasting, the effect of the impregnation method (evaporation, solid–liquid and two-solvent) of the SBA-15 silica template on the morphology of NiCo₂O₄ replica is investigated. The evaporation method seems to be the best choice to obtain mesoporous NiCo₂O₄ powder which, after calcination at 375 °C and subsequent template removal, displays the highest surface area (93.1 m²/g). We have also checked the feasibility of the one-step nanoscating approach for the synthesis of ordered NiCo₂O₄ arrays, though this methodology entails severe difficulties, mainly related to the different decomposition temperature of the nitrate precursors and the P123 surfactant. Finally, randomly oriented, aggregated NiCo₂O₄ nanoparticles are obtained by means of P123 surfactant-assisted soft-templating approach.     

A survey on multi-objective evolutionary algorithms for many-objective problems

Multi-objective evolutionary algorithms (MOEAs) are well-suited for solving several complex multi-objective problems with two or three objectives. However, as the number of conflicting objectives increases, the performance of most MOEAs is severely deteriorated. How to improve MOEAs’ performance when solving many-objective problems, i.e. problems with four or more conflicting objectives, is an important issue since a large number of this type of problems exists in science and engineering; thus, several researchers have proposed different alternatives. This paper presents a review of the use of MOEAs in many-objective problems describing the evolution of the field, the methods that were developed, as well as the main findings and open questions that need to be answered in order to continue shaping the field.     

Thermal Plasma Decomposition of Tetrachloroethylene

Tetrachloroethylene (C₂Cl₄) has been used widely as a solvent and dry cleaning agent, but was later specified as possible human carcinogen. As a result, its safe treatment became a priority. In this paper, we report on its decomposition in an atmospheric radiofrequency thermal plasma reactor. Main components of the exhaust gases were determined by Fourier transform infrared spectroscopy. We found that complete decomposition can be achieved in either oxidative or reductive conditions but not in neutral one. The solid soot product was characterised by transmission electron microscopy and specific surface area measurement. Organic compounds adsorbed on the surface of the soot were extracted by toluene and comprised, based on gas chromatography mass spectrometry, of various perchlorinated aliphatic (for example hexachlorocyclopentadiene) and aromatic compounds (like hexachlorobenzene, octachloronaphthalene or octachloroacenaphthylene). Several nitrogen containing molecules were also identified whose presence are rare during thermal plasma treatments. Further investigation of the extract by mass spectrometry revealed various higher molar mass chlorinated carbon clusters and two types of fullerenes (C₆₀ and C₇₀).     

The Synthesis of N,N‐Bis(dialkoxyphosphinoylmethyl)‐ and N,N‐Bis(diphenylphosphinoylmethyl)glycine Esters by the Microwave‐Assisted Double Kabachnik–Fields Reaction

The condensation of a glycine ester, two equivalents of paraformaldehyde, and the same quantity of a dialkyl phosphite or diphenylphosphine oxide afforded the title compounds as new bis(phospha‐Mannich) products under microwave (MW) conditions at 100°C. The dialkoxyphosphinoylmethyl derivatives were synthesized under solvent‐free conditions, whereas the diphenylphosphinoylmethyl derivatives were synthesized in acetonitrile solution. Comparative thermal experiments showed the beneficial role of MW in respect of efficiency.     

Shaping of ultrashort pulses using bulk acousto-optic filter

Our paper deals with temporal shaping of ultrashort pulses by direct spectral filtering performed with bulk acousto-optic filters using noncollinear geometry. This geometry allows arbitrary optical pulse repetition rate and high diffraction efficiency at relatively large optical apertures. A theoretical model of the pulse shaper is presented, emphasizing the degrees of freedom in this shaping technique. Phase and angular dispersion effects are analyzed, and experimental results on generating controllable pulse trains are presented. PACS 42.65.Re; 42.79.J     

A mathematical theory of strong emergence using multiscale variety

We argue conceptually and then demonstrate mathematically that it is possible to define a scientifically meaningful notion of strong emergence. A strong emergent property is a property of the system that cannot be found in the properties of the system's parts or in the interactions between the parts. The possibility of strong emergence follows from an ensemble perspective, which states that physical systems are only meaningful as ensembles rather than individual states. Emergent properties reside in the properties of the ensemble rather than of any individual state. A simple example is the case of a string of bits including a parity bit, i.e. the bits are constrained to have, e.g., an odd number of ON bits. This constraint is a property of the entire system that cannot be identified through any set of observations of the state of any or all subsystems of the system. It is a property that can only be found in observations of the state of the system as a whole. A collective constraint is a property of the system, however, the constraint is caused when the environment interacts with the system to select the allowable states. Although selection in this context does not necessarily correspond to biological evolution, it does suggest that evolutionary processes may lead to such emergent properties. A mathematical characterization of multiscale variety captures the implications of strong emergent properties on all subsystems of the system. Strong emergent properties result in oscillations of multiscale variety with negative values, a distinctive property. Examples of relevant applications in the case of social systems include various allocation, optimization, and functional requirements on the behavior of a system. Strongly emergent properties imply a global to local causality that is conceptually disturbing (but allowed!) in the context of conventional science, and is important to how we think about biological and social systems. © 2004 Wiley Periodicals, Inc. Complexity 9: 15–24, 2004     

Directed Path-width and Monotonicity in Digraph Searching

Directed path-width was defined by Reed, Thomas and Seymour around 1995. The author and P. Hajnal defined a cops-and-robber game on digraphs in 2000. We prove that the two notions are closely related and for any digraph D, the corresponding graph parameters differ by at most one. The result is achieved using the mixed-search technique developed by Bienstock and Seymour. A search is called monotone, in which the robber's territory never increases. We show that there is a mixed-search of D with k cops if and only if there is a monotone mixed-search with k cops. For our cops-and-robber game we get a slightly weaker result: the monotonicity can be guaranteed by using at most one extra cop. On leave from Bolyai Institute, University of Szeged, Hungary. This research has been supported by a Marie Curie Fellowship of the European Community under contract number HPMF-CT-2002-01868 and by OTKA Grants F.030737 and T.34475.