Measurement of storage time, estimation of ion number and study of absorption line profile in a Paul trap

Europium (Eu⁺) ions were confined in a Paul trap and detected by non-destructive method. Storage time of Eu⁺ ions achieved in vacuum was improved by orders of magnitude employing buffer gas cooling. The experimentally detected signal was fitted to the ion response signal and the total number of ions trapped was estimated. It is found that the peak signal amplitude as well as the product of FWHM and the peak signal amplitude is proportional to the total number of trapped ions. The trapped ion secular frequency was swept at different rates and its effect on the absorption line profile was studied both experimentally and theoretically.     

Development of a Synthetic Route to Unsymmetrical Triphosphine Ligands and an Investigation of Their Coordination Chemistry with Nickel and Palladium

Chiral tridentate phosphines, R(2)P(CH(2))(3)PPh(CH(2))(2)PPh(2) where R = C(6)H(5), p-ClC(6)H(4), and p-FC(6)H(4), can be prepared from simple starting materials, (R(3)P, I(CH(2))(3)I, and Ph(2)P(CH(2))(2)PPh(2)), in a few stages involving phosphonium salts and phosphine oxides as intermediates. Crystalline diamagnetic complexes of nickel(II) and palladium(II) have been isolated. In solution these show first-order 12 line (31)P NMR spectra consistent with three nonequivalent phosphorus nuclei coupled to one another in a square planar geometry. A single X-ray crystallographic study of NiI(2){P(CH(2))(3)PPh(CH(2))(2)PPh(2)} showed that this was square pyramidal in the solid state with a weakly held apical iodo ligand.     

Das Aequivalentgewicht des Kohlenstoffs

Ohne Zusammenfassung     

Clock and Rods—Or Something More Fundamental?

This paper is essentially a speculation on the realization of Mach's Principle, and we came to the details of the present analysis via the formulation of two questions: (a) Can a globally inertial space &; time be associated with a non-trivial global matter distribution? (b) If so, what are the general properties of such a global distribution? These questions are addressed within the context of an extremely simple model universe consisting of particles possessing only the property of enumerability existing in a formless continuum.Since there are no pre-specified ideas of clocks and rods in this model universe, we are forced into two fundamental considerations, these being: What invariant meanings can be given to the concepts of spatial displacement and elapsed time in this model universe? Briefly, these questions are answered as follows: the spatial displacement of a particle is defined in terms of its changed relationship with the particle ensemble as a whole—this is similar to the man walking down a street who can estimate the length of his walk by reference to his changed view of the street. Once the concept of invariant spatial displacement is established, a corresponding concept of elapsed time then emerges in a natural way as ‘process’ within the system. Thus, unlike for example, general relativity, which can be considered as a theory describing the behaviour of specified clocks and rods in the presence of matter, the present analysis can be considered as a rudimentary—but fundamental—theory of what underlies the concepts of clocks and rods in a material universe. In answer to the original two questions, this theory tells us that a globally inertial space &; time can be associated with a non-trivial global matter distribution, and that this distribution is necessarily fractal with D = 2. This latter result is compared with the results of modern surveys of galaxy distributions which find that such distributions are quasi-fractal with D ? 2 on the small-to-medium scales, with the situation on the medium-to-large scales being a topic of considerable debate. Accordingly, and bearing in mind the extreme simplicity of the model considered, the observational evidence is consistent with the interpretation that the analysed point-of-view captures the cosmic reality to a good first-order approximation. We consider the implications of these results.     

The elastic behaviour of gels during the structure formation process

Summary A simple modification of the stress-strain relation for a normal viscoelastic material has been derived for a gel with temporary structural bonds which is subjected to small deformations during gelation. This shows that the storage modulus should separate into two parts, one dependent on frequency and the other on the time for which the gel has been allowed to set. The loss modulus should depend only on frequency. These theoretical results, and others concerning creep under constant stress are in general agreement with observations on a number of gels. Exceptions occur, however, in the period immediately after preparation (before continuous structure has formed) and also after long periods of time during which irreversible changes can have occurred. Certain anomalies appear when the basic assumption of the theory are applied to structure formation in gels with permanent bonds, and a possible resolution of these is suggested.

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Zusammenfassung Es wird eine einfache Modifikation der Spannungs-Dehnungs-Beziehungen normaler viskoelastischer Stoffe abgeleitet, durch die das Verhalten eines Gels mit temporärer Bindungsstruktur bei kleinen Deformationen während des Geliervorgangs beschrieben werden kann. Diese sagt voraus, daß der Speichermodul in zwei Teile aufspaltet, wobei der eine von der Frequenz und der andere von der Erstarrungszeit des Gels abhängt. Dagegen sollte der Verlustmodul nur von der Frequenz abhängig sein. Diese theoretischen Voraussagen, sowie die daraus abgeleiteten Folgerungen bezüglich des Kriechens unter konstanter Spannung, stimmen durchweg mit den an einer Anzahl von Gelen gemachten Beobachtungen überein. Abweichungen kommen dagegen in der Zeit unmittelbar nach der Herstellung vor (bevor sich eine durchgehende Struktur gebildet hat) und nach einer so langen Zeitspanne, daß irreversible Strukturänderungen entstanden sein können. Gewisse Anomalien treten in Erscheinung, wenn die Grundvoraussetzungen der Theorie auf die Strukturbildung bei Gelen mit permanenten Bindungen angewendet werden. Hierfür wird eine mögliche Deutung vorgeschlagen.

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With 3 figures     

Correction: Dermatan sulfate in tunicate phylogeny: Order-specific sulfation pattern and the effect of [→4IdoA(2-Sulfate)β-1→3GalNAc(4-Sulfate)β-1→] motifs in dermatan sulfate on heparin cofactor II activity

After the publication of the work entitled "Dermatan sulfate in tunicate phylogeny: Order-specific sulfation pattern and the effect of [→4IdoA(2-Sulfate)β-1→3GalNAc(4-Sulfate)β-1→] motifs in dermatan sulfate on heparin cofactor II activity", by Kozlowski et al., BMC Biochemistry 2011, 12:29, we found that the legends to Figures 2 to 5 contain serious mistakes that compromise the comprehension of the work. This correction article contains the correct text of the legends to Figures 2 to 5.