Applications of the method of continuous variations (MCV or the Method of Job) to problems of interest to organometallic chemists are described. MCV provides qualitative and quantitative insights into the stoichiometries underlying association of m molecules of A and n molecules of B to form AmBn . Applications to complex ensembles probe associations that form metal clusters and aggregates. Job plots in which reaction rates are monitored provide relative stoichiometries in rate-limiting transition structures. In a specialized variant, ligand- or solvent-dependent reaction rates are dissected into contributions in both the ground states and transition states, which affords insights into the full reaction coordinate from a single Job plot. Gaps in the literature are identified and critiqued.

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Method of Continuous Variations: Applications of Job Plots to the Study of Molecular Associations in Organometallic Chemistry[**]

Objective We explore here a novel model for amyloidogenesis in Alzheimer's disease (AD). This new perspective on AD amyloidosis seeks to provide a rational framework for incorporating recent and seemingly independent findings on the antimicrobial role of β-amyloid and emerging experimental, genetic, and epidemiological data, suggesting innate immune-mediated inflammation propagates AD neurodegeneration. Background AD pathology is characterized by cerebral deposition of amyloid-β protein (Aβ) as β-amyloid. Genetic studies have confirmed the key role of Aβ in AD, revealing that mutation-mediated shifts in the peptides generation lead to early onset familial Alzheimer's disease. However, Aβ generation appears normal for the majority of AD patients, who lack early onset familial Alzheimer's disease mutations. In prevailing models of nonfamilial AD, individual genetics and age-associated changes in brain milieu promote an intrinsically abnormal propensity of Aβ for self-association. However, emerging findings are increasingly inconsistent with characterization of Aβ oligomerization as a nonphysiological and exclusively pathological activity. Recent studies suggest Aβ is an ancient, highly conserved effector molecule of innate immunity. Moreover, Aβ oligomerization and β-amyloid generation appear to be important innate immune pathways that mediate pathogen entrapment and protect against infection. New AD amyloidogenesis model Recent findings on inflammation-mediated neurodegeneration and the role of Aβ in immunity have led to emergence of the "Antimicrobial Protection Hypothesis" of AD. In this model, β-amyloid deposition is an early innate immune response to genuine, or mistakenly perceived, immunochallenge. Aβ first entraps and neutralizes invading pathogens in β-amyloid. Aβ fibrillization drives neuroinflammatory pathways that help fight the infection and clear β-amyloid/pathogen deposits. In AD, chronic activation of this pathway leads to sustained inflammation and neurodegeneration. Mounting data link elevated brain microbe levels with AD. The Antimicrobial Protection Hypothesis reveals how increased brain microbial burden may directly exacerbate β-amyloid deposition, inflammation, and AD progression. Amyloid cascade hypothesis In the antimicrobial protection model, the modality of Aβ's pathophysiology is shifted from abnormal stochastic behavior toward dysregulated innate immune response. However, β-amyloid deposition in AD still leads to neurodegeneration. Thus, the new model extends but remains broadly consistent with the Amyloid Cascade Hypothesis and overwhelming data showing the primacy of Aβ in AD pathology.

The antimicrobial protection hypothesis of Alzheimer's disease.

Author(s): Ahn, KH; Wu, XW; Liu, K; Chien, CL | Abstract: The effect of Fe doping (l20%) on the Mn site in the ferromagnetic ((Formula presented)) and the antiferromagnetic ((Formula presented)) phases of (Formula presented) has been studied. The same ionic radii of (Formula presented) and (Formula presented) cause no structure change in either series, yet conduction and ferromagnetism have been consistently suppressed by Fe doping. Colossal magnetoresistance has been shifted to lower temperatures, and in some cases enhanced by Fe doping. Doping with Fe bypasses the usually dominant lattice effects, but depopulates the hopping electrons and thus weakens the double exchange. © 1996 The American Physical Society.

Magnetic properties and colossal magnetoresistance of LaÑCaÖMnO3 materials doped with Fe

Zeolite 4A (LTA) has been successfully synthesized by a hydrothermal method, where kaolin was used as silica and alumina source. The synthesized zeolite was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), laser granulometry, and FTIR spectroscopy. XRD data from the Rietveld refinement method confirmed only one crystallographic phase. Zeolite A morphology was observed by SEM analysis, and it showed well-defined crystals with slightly different sizes but with the same cubic shape. Particle size distribution of the crystals was confirmed by laser granulometry, whereas FTIR spectroscopy revealed significant structural differences between the starting material and the final zeolite product used as water softener.

Structural analysis of zeolite NaA synthesized by a cost-effective hydrothermal method using kaolin and its use as water softener.

The effects of substrate temperature on the structural, optical, medical and electrical characteristics of Cadmium Oxide (CdO) films are investigated in the current study. Films are deposited on glass substrate at different temperatures, ranged between 450–600 oC, using Spray Pyrolysis Technique. According to X–Ray Diffraction (XRD), it is found that the films are polycrystalline and Cadmium Oxide (CdO) is of a hexagonal wurtzite structure which the preferred direction of its crystal plane is (002). The maximum optical transmittance of films is more than 85%. The size of crystallites is calculated with the maximum value in 500o C. Furthermore, Cadmium Oxide (CdO) nanoparticles were synthesized in deionized water by laser ablation of Cadmium plate. In the current paper, the effects of laser pulse energy and wavelength on the characteristics of Cadmium Oxide (CdO) nanoparticles were studied. Analyses of Transmission Electron Microscope (TEM) were confirmed that size distribution of Cadmium Oxide (CdO) nanoparticles is reduced by increase in laser pulse energy. Fluorescence spectrum of Cadmium Oxide (CdO) nanoparticles shows violet emission accompanied by blue and green band. UV emission with high intensity shows that nanostructure of Cadmium Oxide (CdO) is of a little deficiency. Also, the current study aims to study the linear and non–linear optical characteristics of Cadmium Oxide (CdO) nanoparticles and their applications. Firstly, fluorescence spectrum, as a linear characteristics of Cadmium Oxide (CdO), as well as second harmonic generation and two photons absorption, as non–linear characteristics of Cadmium Oxide (CdO), are studied. Then, some aspects of medicinal and pharmaceutical applications of Cadmium Oxide (CdO) nanoparticles for eliminating cancer cells such as the effect of Cadmium Oxide (CdO) nanoparticles on DNA of human cancer cells and the interaction of Cadmium Oxide (CdO) nanoparticles with DNA of cancer cells are originally investigated. It should be noted that the range of considered parameters are separately clarified and explained in each of related sections (Figure 1).

/pdf/study-of-composition-and-morphology-of-cadmium-oxide-cdo-3fs9axs4om.pdf

Study of Composition and Morphology of Cadmium Oxide (Cdo) Nanoparticles for Eliminating Cancer Cells

http://chuma.cas.usf.edu/~ming/Publications/abstracts/BMCL14943(2009).pdf

A plausible role of salivary copper in antimicrobial activity of histatin-5—Metal binding and oxidative activity of its copper complex

Calorimetric, optical and catalytic activity studies of europium chloride-polyvinyl alcohol composite system

A novel synthesis of NaA zeolite encapsulated iron(III) Schiff base complex: Photocatalytic oxidation of direct blue-1 dye with hydrogen peroxide

http://chuma.cas.usf.edu/%7Eming/Publications/abstracts/ICA2005.pdf

Effective heterogeneous hydrolysis of phosphodiester by pyridine-containing metallopolymers

The Raman (3700–100 cm−1) and infrared (4000–400 cm−1) spectra of liquid 2-aminothiophenol (2ATP) have been recorded and complemented with quantum mechanical calculations. Ten rotational isomers (Cs and/or C1 symmetry) have been considered due to the rotation of NH2 moiety around C–N bond, while the in-plane SH group is directed towards and/or away from NH2, respectively. Initial computational results are in favor of two conformers where the SH group is directed towards the NH2 moiety with C1 symmetry (7; gauche-1, 8; trans). An additional gauche-2 isomer (11) was revealed; with NH2 moiety perpendicular to the benzene ring and the out-of-plane SH group is directed towards NH2 while the lone pairs of electrons on nitrogen and sulfur atoms reside in opposite directions. From MP2/6-31G(d) calculations, the gauche-2 (11) is predicted to be more stable than trans (8) and gauche-1 (7) by 758 (2.17 kcal/mol) and 833 cm−1 (2.38 kcal/mol), respectively. Aided by theoretical and experimental outcomes, gauche-2 (11) conformer appears to dominate the liquid phase with minor spectroscopic features relating to gauche-1 (7) and/or trans (8) conformers. Aided by normal coordinate analysis, force constants and frequency calculations, a complete vibrational assignment has proposed for 2ATP (HSC6H4NH2) and its deuterated analogue (DSC6H4ND2). The structural parameters were optimized without any constrains with the addition of polarization and diffusion functions at 6-311+G(d) and 6-31++G(d,p) basis sets using RHF, MP2 and B3LYP, all in favor of gauche-2 (11) conformer. Additionally, the SH and NH2 barriers to internal rotations have been considered for 2-aminothiophenol and compared with 2-aminophenol (2AP).

Ahmed I. Hanafy

Papers

A plausible role of salivary copper in antimicrobial activity of histatin-5—Metal binding and oxidative activity of its copper complex

Calorimetric, optical and catalytic activity studies of europium chloride-polyvinyl alcohol composite system

A novel synthesis of NaA zeolite encapsulated iron(III) Schiff base complex: Photocatalytic oxidation of direct blue-1 dye with hydrogen peroxide

Effective heterogeneous hydrolysis of phosphodiester by pyridine-containing metallopolymers

Conformational stability, barriers to internal rotation of 2-aminothiophenol (d0 and d3): A combined vibrational and theoretical approach