On strongly stable normal operators in Krein spaces

For bounded normal operators in Krein spaces we give a necessary and sufficient condition for strong stability. The same result for unitary operators was obtained by M.G.Krein [1] (see also [2]). For selfadjoint operators we refer to the papers of P.Jonas, H.Langer [3] and H.Langer [4].     

Metal-stabilized phenoxonium cation

An unprecedented metal-stabilized phenoxonium cation was prepared by a process involving dearomatization of a phenoxy complex. The unique eta2 C=O-metal (iridium) coordination mode leaves the positive charge delocalized within the former aromatic ring. The X-ray structure and conversion into eta2 C=O-coordinated metal-quinone complex are described.     

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.     

Kinetic and spectroscopic studies of the [palladium(Ar-bian)]-catalyzed semi-hydrogenation of 4-octyne

The kinetics of the stereoselective semi-hydrogenation of 4-octyne in THF by the highly active catalyst [Pd{(m,m'-(CF(3))(2)C(6)H(3))-bian}(ma)] (2) (bian = bis(imino)acenaphthene; ma = maleic anhydride) has been investigated. The rate law under hydrogen-rich conditions is described by r = k[4-octyne](0.65)[Pd][H(2)], showing first order in palladium and dihydrogen and a broken order in substrate. Parahydrogen studies have shown that a pairwise transfer of hydrogen atoms occurs in the rate-limiting step. In agreement with recent theoretical results, the proposed mechanism consists of the consecutive steps: alkyne coordination, heterolytic dihydrogen activation (hydrogenolysis of one Pd-N bond), subsequent hydro-palladation of the alkyne, followed by addition of N-H to palladium, reductive coupling of vinyl and hydride and, finally, substitution of the product alkene by the alkyne substrate. Under hydrogen-limiting conditions, side reactions occur, that is, formation of catalytically inactive palladacycles by oxidative alkyne coupling. Furthermore, it has been shown that (Z)-oct-4-ene is the primary reaction product, from which the minor product (E)-oct-4-ene is formed by an H(2)-assisted, palladium-catalyzed isomerization reaction.     

Reactivity within a confined self-assembled nanospace

Confined nanospaces in which reactions can take place, have been created by various approaches such as molecular capsules, zeolites and micelles. In this tutorial review we focus on the application of self-assembled nanocapsules with well-defined cavities as nanoreactors for organic and metal catalysed transformations. The self-assembly of nanocapsules based on noncovalent bonds such as hydrogen bonds and metal-ligand interactions is discussed to introduce the properties of the building blocks and capsules thereof. We will elaborate on the encapsulation effects that can be expected when reactions are carried out in a capsule-protected environment. Subsequently, literature examples will be described in which self-assembled nanocapsules are applied as nanoreactors, for various types of organic and metal catalysed reactions.     

Bisphosphine based hetero-capsules for the encapsulation of transition metals

Just mixing of solutions of tetracationic diphosphine ligands and tetraanionic calix[4]arene building blocks leads to the formation of supramolecular heterocapsules that coordinate a palladium metal within the cavity of the assembly, giving rise to a new class of potential supramolecular transition metal catalysts.     

SQUID-based measuring systems

A program has been developed and initiated at the Indira Gandhi Centre for Atomic Research (IGCAR) for the utilization of SQUID sensors in various application areas. DC SQUID sensors based on Nb-AlO _x -Nb Josephson junctions have been designed and developed inhouse along with associated flux-locked loop (FLL) electronics. A compact low field SQUID magnetometer insertible in a liquid helium storage dewar has also been developed inhouse and is in use. Efforts to build a high field SQUID magnetometer, SQUID-DAC system, are in progress. A planar gradiometric DC SQUID sensor for non-destructive evaluation (NDE) application to be used in relatively unshielded environment has been designed and developed. An easily portable NDE cryostat with a small lift-off distance, to be used in external locations has been designed and tested. The magnetic field produced by a given two-dimensional current density distribution is inverted using the Fourier transform technique.     

Diphosphine Capsules for Transition‐Metal Encapsulation

Self‐assembly and characterization of novel heterodimeric diphosphine capsules formed by multiple ionic interactions and composed of one tetracationic diphosphine ligand and one complementary tetraanionic calix[4]arene are described. Encapsulation of a palladium atom within a diphosphine capsule is achieved successfully by using the metal complex of the tetracationic diphosphine ligand for the assembly process. In this templated approach to metal encapsulation, the transition‐metal complex is an integrated part of the capsule with the transition metal located inside the capsule and is not involved in the assembly process. We present two approaches for capsule assembly by mixing solutions of the precharged building blocks in methanol and mixing solutions of the neutral building blocks in methanol. The scope of the diphosphine capsules and the metallodiphosphine capsules is easily extended by applying tetracationic diphosphine ligands with different backbones (ethylene, diphenyl ether, and xanthene) and cationic binding motifs (p‐C₆H₄‐CH₂‐ammonium, m‐C₆H₄‐ammonium, and m‐C₆H₄‐guanidinium). These tetracationic building blocks with different flexibilities and shapes readily associate into capsules with the proper capsular structure, as is indicated by ¹H NMR spectroscopy, 1D NOESY, ESI‐MS, and modeling studies.     

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.     

Paraquat induces oxidative stress, neuronal loss in substantia nigra region and Parkinsonism in adult rats: Neuroprotection and amelioration of symptoms by water-soluble formulation of Coenzyme Q10

Background  

Parkinson's disease, for which currently there is no cure, develops as a result of progressive loss of dopamine neurons in the brain; thus, identification of any potential therapeutic intervention for disease management is of a great importance.