An uncommon highly oxidized multiple bonded Re2(8+) species

A long-sought metal-metal bonded species with an M(2)(8+) core has been structurally characterized. The diamagnetic compound {[Re(2)(hpp)(3)(OH)(O(3)SCF(3))](2)(μ-O)(2)}(O(3)SCF(3))(2), 2, has two σ(2)π(4) electron-poor triple-bonded Re(2)(8+) units embraced by three bicyclic guanidinate ligands (hpp) and axial OH and triflate groups; the two dimetal units are held together by bridging oxo-groups.     

Synthesis,characterization, crystal structure and toxicity evaluation of Co (II), Cu (II), Mn (II), Ni (II), Pd (II) and Pt (II) complexes with Schiff base derived from 2-chloro-5-(trifluoromethyl)aniline

A bidentate NO donor Schiff base, 2-(((2-chloro-5- (trifluoromethyl)phenyl)imino)methyl) phenol ( HL ¹ ) and its complexes [Co(L¹)₂(H₂O)₂] ( 1 ), [Cu(L¹)₂] ( 2 ), [Mn(L¹)₂(H₂O)₂] ( 3 ), [Ni(L¹)₂(H₂O)₂] ( 4 ), [Pd₂(L¹)₂(OAc)₂·1.16H₂O] ( 5 ), [Pt(L¹)₂] ( 6 ) were synthesized and characterized by different physico-chemical techniques including elemental and thermal analysis, magnetic susceptibility measurements, molar electric conductivity, IR, ¹H-NMR, ¹³C-NMR, UV–Vis, mass spectroscopies and X-ray powder diffraction (XRD). The molecular structures of ligand HL ¹ and two complexes ( 2 and 5 ) were confirmed by X-ray crystallography analysis on the monocrystal. In this complexes, the metal ions are in distorted square-planar environments. The copper (II) complex is mononuclear and crystallized in a monoclinic space group P21/c, whereas palladium (II) complex is dinuclear and crystallized in the trigonal crystal system R-3. The toxicity of the ligand and complexes was evaluated on both plant and animal cells, using the plant species Triticum aestivum L. and the crustacean Artemia franciscana Kellogg. At concentrations up to 100 μM the compounds presented very little toxicity on Artemia franciscana Kellogg. Moreover, the palladium (II) complex was devoid of any toxicity on the plant cells.     

Phenotypic Assays for β-Amyloid in Mouse Embryonic Stem Cell-Derived Neurons

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Informal Networks and Resistance to Organizational Change: The Introduction of Quality Standards in a Transport Company

In this paper we investigate the association between resistance to the introduction of ISO quality standards in a transport company and three effects of the informal advice and trust networks in the organization. The analysis includes four prevailing explanations from the literature on organizational resistance: job satisfaction, perceived legitimacy, unit grouping and decision making authority. The network effects we propose are: (a) a contagion effect, which predicts that members with the same opinion tend to have close or equal trust and advice relations; (b) a prominence effect, which predicts that prominent actors in the trust network show less resistance than other members—and that prominent members of the advice network show more resistance than less prominent actors; (c) a role equivalence effect, which predicts that members with the same patterns of combined trust/advice relations show the same resistance. The paper presents the operationalization and measurement of the variables and the results of three analyses to test the effects. Contagion of resistance appears to be very significant in the trust network. Resistance gradually erodes in the trust network when moving from management to employees. Members who are trusted in the transport company are significantly less resistant to the introduction of the quality standards than members who are not especially trusted. This network effect is controlled for the significant effects of job satisfaction and perceived legitimacy. The role equivalence structure of the combined trust/advice network does not explain the resistance. We conclude that informal networks have important effects on resistance to the proposed changes in the transport company. The case study shows how network analysis can be used to empirically test for effects of social relations in organizations.     

Guidelines for dynamics‐based parameterization of one‐dimensional cellular automata rule spaces

As paradigmatic complex systems, various studies have been done in the context of one‐dimensional cellular automata (CA) on the definition of parameters directly obtained from their transition rule, aiming at the help they might provide to forecasting CA dynamic behavior. Out of the analysis of the most important parameters available for this end, as well as others evaluated by us, a set of guidelines is proposed that should be followed when defining a parameter of that kind. Based upon the guidelines, a critique of those parameters is made, which leads to a set of five that jointly provide a good forecasting set; two of them were drawn from the literature and three are new ones defined according to the guidelines. By using them as a heuristic in the evolutionary search for CA of a predefined computational behavior, good results have been obtained, exemplified herein by the evolutionary search for CA that perform the Synchronization Task. © 2001 John Wiley & Sons, Inc.     

Comparative study of the behavior of carboxymethyl cellulose-g-poly(N-isopropylacrylamide) copolymers and their equivalent physical blends

A comparative study of the behavior of carboxymethyl cellulose and poly(N-isopropylacrylamide) (PNIPAM) as graft copolymers and physical blends, in solution and in solid state was accomplished by viscometry, turbidimetry, IR spectroscopy, X-ray diffraction, thermogravimetry, and enzymatic degradation. Both in diluted and concentrated solutions, the graft copolymers exhibited a thermothickening effect, while the corresponding mixtures of the two components exhibited an Arrhenius behavior. Solid phase investigations showed morphological differences between graft copolymers and their equivalent physical blends. The enzymatic degradation behavior is essentially similar both for copolymers and blends (enzymatic degradation activity has similar values) although a slight increased enzymatic activity was noticed for the graft copolymers in comparison with the blends.     

Structure and activity of LaMn1?yCoyO3 perovskites

Substituted LaMn_1−yCo_yO₃ perovskite-type oxides (0.0 ≤ y ≤ 1.0) prepared by the citrae method, have been investigated as catalysts in the total combustion of acetylacetate. The characterization results indicate that the catalytic activity is enhanced in the substituted perovskites. The most active is the one with y = 0.5.