Ultraheavy Yukawa-bound states of fourth-generation at Large Hadron Collider

A study of bound states of the fourth-generation quarks in the range of 500?C700 GeV is presented, where the binding energies are expected to be mainly of Yukawa origin, with QCD subdominant. Near degeneracy of their masses exhibits a new ??isospin??. The production of a colour-octet, isosinglet vector meson via $q\bar q \to \omega_8$ is the most interesting. Its leading decay modes are $\pi_8^\pm W^\mp$ , $\pi_8^0Z^0$ , and constituent quark decay, with $q\bar q$ and $t\bar t'$ and $b\bar b'$ subdominant. The colour octet, isovector pseudoscalar ?? ₈ meson decays via constituent quark decay, or to Wg. This work calls for more detailed study of fourth-generation phenomena at LHC.     

Ion chemistry of anti-o,o dibenzene

The ion chemistry of anti-o,o'-dibenzene (1) was examined in the gaseous and the condensed phase. From a series of comparative ion cyclotron resonance (ICR) mass spectrometry experiments which involved the interaction of Cu+ with 1, benzene, or mixtures of both, it was demonstrated that 1 can be brought into the gas phase as an intact molecule under the experimental conditions employed. The molecular ions, formally 1*+ and 1*- , were investigated with a four-sector mass spectrometer in metastable-ion decay, collisional activation, charge reversal, and neutralization-reionization experiments. Surprisingly, the expected retrocyclization to yield two benzene molecules was not dominant for the long-lived molecular ions; however, other fragmentations, such as methyl and hydrogen losses, prevailed. In contrast, matrix ionization of 1 in freon (77 K) by gamma-radiation or in argon (12 K) by X-irradiation leads to quantitative retrocyclization to the cationic dimer of benzene, 2*+. Theoretical modeling of the potential-energy surface for the retrocyclization shows that only a small, if any, activation barrier is to be expected for this process. In another series of experiments, metal complexes of 1 were investigated. 1/Cr+ was formed in the ion source and examined by metastable ion decay and collisional activation experiments, which revealed predominant losses of neutral benzene. Nevertheless, comparison with the bis-ligated [(C6H6)2Cr]+ complex provided evidence for the existence of an intact 1/Cr+ under these experimental conditions. No evidence for the existence of 1/Fe+ was obtained, which suggests that iron mediates the rapid retrocyclization of 1/Fe+ into the bis-ligated benzene complex [(C6H6)2Fe]+.     

Spray coating of cellulose aerogel particles in a miniaturized spouted bed

Cellulose - Aim of this work is to apply protective and homogeneous shellac coating layers on the surface of hydrophilic open-pore cellulose aerogel particles with low...     

Substituent Effects on Fe+-Mediated [4+2] Cycloadditions in the Gas Phase

The Fe⁺-mediated [4+2] cycloaddition of dienes with alkynes has been examined by four-sector ion-beam and ion cyclotron resonance mass spectrometry. Prospects and limitations of this reaction were evaluated by investigating several Me-substituted ligands. Me Substitution at C(2) and C(3) of the diene, i.e., 2-methylbuta-1,3-diene, 2,3-dimethylbuta-1,3-diene, hardly disturbs the cycloaddition. Similarly, variation of the alkyne by use of propyne and but-2-yne does not affect the [4+2] cycloaddition step, but allows for H/D exchange processes prior to cyclization. In contrast, Me substituents in the terminal positions of the diene moiety (e.g., penta-1,3-diene, liexa-2,4-diene) induce side reactions, namely double-bond migration followed by [3+2] and [5+2] cycloadditions, up to almost complete suppression of the [4+2] cycloaddition for 2,4-dimethylhexa-2,4-diene. Similarly, alkynes with larger alkyl substituents (pent-1-yne, 3,3-dimethylbut-1-yne) suppress the [4 + 2] cycloaddition route. Stereochemical effects have been observed for the (E)- and (Z)-penta-1,3-diene ligands as well as for (E,E)- and (E,Z)-hexa-2,4-diene. A mechanistic explanation for the different behavior of the stereoisomers in the cyclization reaction is developed. Further, the regiochemical aspects operative in the systems ethoxyacetylene/pentadiene/Fe⁺ and ethoxyacetylcne/isoprene/Fe⁺ indicate that substituents avoid proximity.     

Zur elektrostatischen Aufladung von CdS-Einkristallen nach Stromdurchgang

The electrostatic charging od CdS-monocrystals by use of an electric current is described. A statistical analysis of a great number of measurements is given. A general formula for charging is given. The influence of crystal inhomogenieties, boundary layers and field excitation are described.     

Ueber den Multiplicator bei der Bestimmung des Zuckers im Harn nach Roberts

Ohne Zusammenfassung     

Spin hamiltonian for which the chiral spin liquid is the exact ground state

We construct a Hamiltonian that singles out the chiral spin liquid on a square lattice with periodic boundary conditions as the exact and, apart from the twofold topological degeneracy, unique ground state.     

Enhanced ALA-induced fluorescence in hyperparathyroidism

INTRODUCTION: Intraoperative localization of parathyroid glands can be challenging especially in minimally invasive surgery. Fluorescence diagnosis using the photosensitizer aminolevulinic acid (ALA) has been described to identify normal parathyroid glands during experimental bilateral neck exploration. The present study evaluated fluorescence differences between hyperplastic and normal parathyroid glands as a precondition for a clinical application of the technique. MATERIALS AND METHODS: Polycystic kidney disease (PKD) rats with hyperparathyroidism due to hyperplastic parathyroid glands and Wistar rats with normal parathyroid glands were photosensitized by peritoneal lavage with ALA solution. After surgical exposure of thyroid and parathyroid glands the operative site was observed under blue light conditions using the d-light system to assess fluorescence characteristics of each tissue. Fluorescence intensities of parathyroid glands and surrounding thyroid tissue were measured by spectrometry. Parathyroid hormone in serum of the rats was determined by enzyme-linked immunosorbent assay (ELISA). RESULTS: Observation of the exposed thyroid site showed a subjectively stronger red fluorescence of the parathyroid glands in the PKD rats in comparison to the Wistar rats, whereas thyroid tissue appeared equally fluorescent. In the PKD animals, spectrometric fluorescence intensity was 10 times higher in the parathyroid glands than in the thyroid gland, whereas in the Wistar rats the ratio was 3.2:1. Fluorescence intensity in the parathyroid glands was more than twice in the PKD rats than in the Wistar rats, however slightly lower in the thyroid tissue. ELISA confirmed the pathophysiological change of a hyperparathyroidism with significantly increased serum levels of parathyroid hormone in the PKD rats. DISCUSSION: Hyperparathyroidism enhances ALA-induced fluorescence of the parathyroid glands. A combined surgical fluorescence strategy may justify a unilateral, minimally invasive approach in selected patients and serve to improve the capability of the surgeon to safely and efficiently manage parathyroid diseases.     

Optical filters with panchromatic emulsion layers for image processing

Amplitude filters with non-linear adaptive performance in the Fourier plane of a mirror optical system are considered. Panchromatic silver bromide layers with a printout effect are employed. The processing of binary and grey-scale images with the aid of a passively adaptive mirror filtering block is investigated.