Extent and mechanism of metal ion incorporation into precipitated ferrites

The ability of many noniron metals to be incorporated into the structure of ferrites is being utilized in numerous industrial and environmental applications. The incorporation of some of these metals during Fe(II) oxidation-induced precipitation at moderate temperatures (80-100°C) appears to be limited, for reasons not fully understood, and to extents not always agreed (e.g., Ni(2+), Cr(3+)). In this paper, the incorporation maxima of six metals into the structure of precipitated ferrites (in terms of x in Me(x)Fe(3-)(x)O(4), Me represents a noniron metal) were concluded to be 1.0, 1.0, 0.78, 0.49, 0.35, and 0.0 for Zn(2+), Co(2+), Ni(2+), Al(3+), Cd(2+) and Cr(3+), respectively. With the exception of the much larger Cd(2+), these values were associated with kinetic considerations controlled by the H(2)O exchange rate between the hydration shells surrounding the dissolved metal ion.     

Poisson thickening

Let × be a Poisson point process of intensity λ on the real line. A thickening of it is a (deterministic) measurable function f such that X∪f(X) is a Poisson point process of intensity λ′ where λ′ > λ. An equivariant thickening is a thickening which commutes with all shifts of the line. We show that a thickening exists but an equivariant thickening does not. We prove similar results for thickenings which commute only with integer shifts and in the discrete and multi-dimensional settings. This answers 3 questions of Holroyd, Lyons and Soo. We briefly consider also a much more general setup in which we ask for the existence of a deterministic coupling satisfying a relation between two probability measures. We present a conjectured sufficient condition for the existence of such couplings.     

Reactivity of long conjugated systems: selectivity of Diels-Alder cycloaddition in oligofurans

Taking advantage of the synthetic availability and solubility of long oligofurans, their reactivity toward dienophiles was studied as a model for the rarely investigated reactivity of long conjugated systems. Unlike oligoacenes, the reactivity of oligofurans decreases or remains constant with increasing chain length. Terminal ring cycloadducts of oligofurans are kinetically and thermodynamically favored, whereas central ring cycloadducts are preferred in oligoacenes, because of the different driving forces in the two reactions: π-conjugation in oligofurans and aromatization/dearomatization in oligoacenes.     

Continuity of the value and optimal strategies when common priors change

We show that the value of a zero-sum Bayesian game is a Lipschitz continuous function of the players?? common prior belief with respect to the total variation metric on beliefs. This is unlike the case of general Bayesian games where lower semi-continuity of Bayesian equilibrium (BE) payoffs rests on the ??almost uniform?? convergence of conditional beliefs. We also show upper semi-continuity (USC) and approximate lower semi-continuity (ALSC) of the optimal strategy correspondence, and discuss ALSC of the BE correspondence in the context of zero-sum games. In particular, the interim BE correspondence is shown to be ALSC for some classes of information structures with highly non-uniform convergence of beliefs, that would not give rise to ALSC of BE in non-zero-sum games.     

Ultrasensitive Detection of Salmonella and Listeria monocytogenes by Small‐Molecule Chemiluminescence Probes

Detection of Salmonella and L. monocytogenes in food samples by current diagnostic methods requires relatively long time to results (2–6 days). Furthermore, the ability to perform environmental monitoring at the factory site for these pathogens is limited due to the need for laboratory facilities. Herein, we report new chemiluminescence probes for the ultrasensitive direct detection of viable pathogenic bacteria. The probes are composed of a bright phenoxy‐dioxetane luminophore masked by triggering group, which is activated by a specific bacterial enzyme, and could detect their corresponding bacteria with an LOD value of about 600‐fold lower than that of fluorescent probes. Moreover, we were able to detect a minimum of 10 Salmonella cells within 6 h incubation. The assay allows for bacterial enrichment and detection in one test tube without further sample preparation. We anticipate that this design strategy will be used to prepare analogous chemiluminescence probes for other enzymes relevant to specific bacteria detection and point‐of‐care diagnostics.     

Nanomaterial-based electrochemical sensors for detection of glucose and insulin

Journal of Solid State Electrochemistry - Electrochemical sensors for the detection of specific biomolecules have attracted a lot of interest over the recent years due to their high sensitivity,...     

Optical activity of the background caused by sheep organ tissue extracts and its effect on spectrophotometric determination of the herbicide bentazone

Summary Nowadays mainly triazine herbicides are used for treating cultural plants against weeds. Many methods for their determination as well as for their extraction and purification have been developed, but the latter apply mainly for the determination in plant material. In the present publication the effect of the animal organ tissue extracts on the residue determination by optical methods is investigated. The background materials obtained after extraction of sheep muscle, liver, kidney, heart and lung with acetonitrile, acetone and hexane each are investigated by means of an infrared spectrometric method. Bentazone was chosen as the model pesticide and had been toxicologically tested with two experimental groups of sheep throughout three months administered with two different dose rates. Since the main chromophore of the bentazone molecule is represented by a ketonic group which is used for the spectrophotometric determination of the substance, the elimination of the background at the respective UV region should be based on suppression of the optic activity of equivalents of similar absorbing chromophores as owned by the bentazone molecule. For this reason the cleaning capacities of the Separcol SI C18, SI C1 and Carb of Czechoslovak provenience were examined. After elimination of interfering background bentazone determination was verified at a wavelength of 219 nm.     

A class of time-machine solutions with a compact vacuum core

We present a class of curved-spacetime vacuum solutions which develop closed timelike curves at some particular moment. We then use these vacuum solutions to construct a time-machine model. The causality violation occurs inside an empty torus, which constitutes the time-machine core. The matter field surrounding this empty torus satisfies the weak, dominant, and strong energy conditions. The model is regular, asymptotically flat, and topologically trivial. Stability remains the main open question.