Local convergence of quasi-Newton methods for B-differentiable equations

We study local convergence of quasi-Newton methods for solving systems of nonlinear equations defined by B-differentiable functions. We extend the classical linear and superlinear convergence results for general quasi-Newton methods as well as for Broyden's method. We also show how Broyden's method may be applied to nonlinear complementarity problems and illustrate its computational performance on two small examples.     

Ruthenium porphyrin catalyzed intramolecular carbenoid C[bond]H insertion. Stereoselective synthesis of cis-disubstituted oxygen and nitrogen heterocycles

[reaction: see text] A ruthenium porphyrin-catalyzed stereoselective intramolecular carbenoid C[bond]H insertion is described. Using [Ru(II)(TTP)(CO)] as catalyst, aryl tosylhydrazones are converted to 2,3-dihydrobenzofurans, 2,3-dihydroindoles, and beta-lactams in good yields and remarkable cis selectivity (up to 99%). Enantioselective synthesis of 2,3-dihydrobenzofurans is also achieved with [Ru(II)(D(4)-Por*)(CO)] as catalyst, and up to 96% ee is attained.     

Synthesis, photophysical and electrophosphorescent properties of fluorene-based platinum(II) complexes

A series of platinum(II) complexes bearing tridentate cyclometalated C^N^N (C^N^N=6-phenyl-2,2'-bipyridine and π-extended R-C^N^N=3-[6'-(naphthalen-2'-yl)pyridin-2'-yl]isoquinoline) ligands with fluorene units have been synthesised and their photophysical properties have been studied. The fluorene units are incorporated into the cyclometalated ligands by a Suzuki coupling reaction. An increase in the π-conjugation of the cyclometalated ligands confers favourable photophysical properties compared to the 6-phenyl-2,2'-bipyridine analogues. The fluorene-based platinum(II) complexes display vibronic-structured emission bands with λ(max)=558-601 nm, and high emission quantum yields up to 0.76 in degassed dichloromethane. Their emissions are tentatively assigned to excited states with mixed (3)IL/(3)MLCT parentage (IL=intraligand, MLCT=metal-to-ligand charge transfer). The crystal structures of these platinum(II) complexes reveal extensive Pt(II)···π and/or π-π interactions. The fluorene-based platinum(II) complexes are soluble in organic solvents, have high thermal stability with decomposition temperature >350 °C, and can be thermally vacuum-sublimed or solution-processed as phosphorescent dopants for the fabrication of organic light-emitting diodes (OLEDs). A monochromic OLED with 3d as dopant (2 wt%) fabricated by vacuum deposition gave a current efficiency of 14.7 cd A(-1) and maximum brightness of 27000 cd m(-2). A high current efficiency (9.2 cd A(-1)) has been achieved in a solution-processed OLED using complex 3f (5 wt%) doped in a PVK (poly(9-vinylcarbazole)) host.     

Coordination networks from Cu cations and tetrakis(methylthio)benzenedicarboxylic acid: tunable bonding patterns and selective sensing for NH(3) gas

This paper aims to illustrate the rich potential of the thioether-carboxyl combination in generating coordination networks with tunable and interesting structural features. By simply varying the ratio between Cu(NO(3))(2) and the bifunctional ligand tetrakis(methylthio)benzenedicarboxylic acid (TMBD) as the reactants, three coordination networks can be hydrothermally synthesized in substantial yields, which present a distinct evolution with regard to metal-ligand interactions. Specifically, Cu(TMBD)(0.5)(H(2)TMBD)(0.5)·H(2)TMBD (1) was obtained with a relatively small (1:1) Cu(NO(3))(2)/TMBD ratio, and crystallizes as an one-dimensional (1D) coordination assembly based on Cu(I)-thioether interactions, which is integrated by hydrogen-bonding to additional H(2)TMBD molecules to form a three-dimensional (3D) composite network with all the carboxylic acid and carboxylate groups remaining uncoordinated to the metal ions. A medium (1.25:1) Cu(NO(3))(2)/TMBD ratio leads to compound Cu(2)TMBD, in which Cu(I) ions simultaneously bond to the carboxylate and thioether groups, while an even higher (2.4:1) Cu(NO(3))(2)/TMBD ratio produced a mixed-cation compound Cu(II)(2)OHCu(I)(TMBD)(2)·2H(2)O (2), in which the carboxylic groups are bonded to (cupric) Cu(II) ions, and the thioether groups to Cu(I). Despite the lack of open channels in 2, crystallites of this compound exhibit a distinct and selective absorption of NH(3), with a concomitant color change from green to blue, indicating substantial network flexibility and dynamics with regards to gas transport.     

Molecular histology analysis by matrix-assisted laser desorption/ionization imaging mass spectrometry using gold nanoparticles as matrix

Gold nanoparticles (AuNPs) were applied and optimized as matrix for matrix-assisted laser desorption/ionization mass spectrometry analysis of animal tissues, and enabled histological analysis of animal tissues at molecular level by imaging mass spectrometry (IMS). AuNPs were coated on animal tissue in a solvent-free manner via argon ion sputtering. Metabolites, including neurotransmitters, fatty acids and nucleobases, were directly detected from mouse brain tissue. Based on region-specific chemical profiles, fine histological features of mouse brain tissue and heterogeneous regions of tumor tissue were both revealed.     

On the strategy of supply chain collaboration based on dynamic inventory target level management: A theory of constraint perspective

After the financial tsunami in 2008, how to adjust the target inventory level dynamically and instantly in order to reduce the risk that an enterprise encountered in a rapid demand changing market has become a crucial issue in the field of supply chain management. This paper explores the strategies of supply chain collaboration by utilizing theory of constraint to achieve the goal of adjusting the target inventory level dynamically. Three time-series-data-mining techniques – Sequential Probability Ratio Test (SPRT), CUSUM chart and Auto-regression Test (AR(1)) are used to detect the timing of market demand change. The results are used to adjust the target inventory level. Simulation techniques are used to explore the relative efficiency of the demand-change detection for the three methods. The techniques are also used to explore the effectiveness of various inventory management strategies on inventory performance based on the three demand change detection methods.     

Highly trans‐Selective Arylation of Achmatowicz Rearrangement Products by Reductive γ‐Deoxygenation and Heck–Matsuda Reaction: Asymmetric Total Synthesis of (−)‐Musellarins A–C and Their Analogues

Fully functionalized pyranuloses derived from Achmatowicz rearrangement (AR) are versatile building blocks in organic synthesis. However, access to trans‐2,6‐dihydropyrans from pyranuloses remains underexplored. Herein, we report a new two‐step trans arylation of AR products to access 2,6‐trans‐dihydropyranones. This new trans‐arylation method built on numerous plausible, but unsuccessful, direct arylation reactions, including Ferrier‐type and Tsuji–Trost‐type reactions, was finally enabled by an unprecedented, highly regioselective γ‐deoxygenation of AR products by using Zn/HOAc and a diastereoselective Heck–Matsuda coupling. The synthetic utility of the reaction was demonstrated in the first asymmetric total synthesis of (?)‐musellarins A–C and 12 analogues in 11–12 steps. The brevity and efficiency of our synthetic route permitted preparation of enantiomerically pure musellarins and analogues (>20 mg) for preliminary cytotoxicity evaluation, which led us to identify two analogues with three‐to‐six times greater potency than the musellarins as promising new leads.     

Tissue-spray ionization mass spectrometry for raw herb analysis

Tissue-spray ionization mass spectrometry is developed for the in situ chemical analysis of raw herbs under ambient conditions. We demonstrated that analyte molecules could be directly sprayed and ionized from solvent-wetted ginseng tissues upon the application of high electrical voltage to the tissue sample. Abundant phytochemicals/ metabolites, including ginsenosides, amino acids and oligosaccharides, could be detected from ginseng tissues when the tissue-spray experiments were conducted in positive ion mode. Thermally labile and easily hydrolyzed malonyl-ginsenosides were also detected in negative ion mode. The tissue-spray ionization method enables the direct detection of analytes from raw herb samples and preserves the sample integrity for subsequent morphological and/ or microscopic examination. In addition, this method is simple and fast for chemical profiling of wild-type and cultivated-type American ginsengs with differentiation.