The Potent Oxidant Anticancer Activity of Organoiridium Catalysts

Platinum complexes are the most widely used anticancer drugs; however, new generations of agents are needed. The organoiridium(III) complex [(η⁵‐Cp^xbiph)Ir(phpy)(Cl)] ( 1‐Cl ), which contains π‐bonded biphenyltetramethylcyclopentadienyl (Cp^xbiph) and C^N‐chelated phenylpyridine (phpy) ligands, undergoes rapid hydrolysis of the chlorido ligand. In contrast, the pyridine complex [(η⁵‐Cp^xbiph)Ir(phpy)(py)]⁺ ( 1‐py ) aquates slowly, and is more potent (in nanomolar amounts) than both 1‐Cl and cisplatin towards a wide range of cancer cells. The pyridine ligand protects 1‐py from rapid reaction with intracellular glutathione. The high potency of 1‐py correlates with its ability to increase substantially the level of reactive oxygen species (ROS) in cancer cells. The unprecedented ability of these iridium complexes to generate H₂O₂ by catalytic hydride transfer from the coenzyme NADH to oxygen is demonstrated. Such organoiridium complexes are promising as a new generation of anticancer drugs for effective oxidant therapy.     

Simultaneous determination of peroxydisulfate and conventional inorganic anions by ion chromatography with the column‐switching technique

The application of ion chromatography with the column‐switching technique for the simultaneous analysis of peroxydisulfate and conventional inorganic anions in a single run is described. With this method, conventional inorganic anions were separated by consecutive elution through both the guard column and separation column, but peroxydisulfate that only passed through the guard column had a good peak shape and short retention time. A series of standard solutions consisting of target anions of various concentrations from 0.01 to 75 mg/L were analyzed, with a correlation coefficient (r) ≥ 0.9990. The limits of detection were in the range of 0.49–9.84 μg/L based on the S/N of 3 and a 25 μL injection volume. RSDs for retention time, peak area, and peak height were all <1.77%. A spiking study was performed with satisfactory recoveries between 97.6 and 103.4% for all anions. The quantitative determination of peroxydisulfate and conventional inorganic anions in surface waters was accomplished within 18 min by this column‐switching technique.     

NMR Spectrometric Analysis of Antazoline

An analytical method is described for the analysis of antazoline [2-(N-benzylanilinomethyl) imidazoline] using pmr. The procedure provides good quantitative results together with a very specific mean for identification of antazoline     

Corrigendum to “Property (gb) and perturbations” [J. Math. Anal. Appl. 383 (1) (2011) 82–94]

We give a complete reference for work cited in [M.H.M. Rashid, Property (gb) and perturbations, J. Math. Anal. Appl. 383 (1) (2011) 82–94].     

New regioisomeric naphthol-substituted thiazole based ratiometric fluorescence sensor for Zn2+ with a remarkable red shift in emission spectra

Ratiometric fluorescent chemosensors based on the position of ring annulation of the naphthol–thiazole moiety for quantification of zinc ions in aqueous ethanol were synthesized and investigated. It was found that sensor 3 exhibited a remarkably large red shift of 140 nm in emission upon complexation with Zn²⁺. A TD-B3LYP/6-31G (d,p) calculation was performed to characterize the nature of the fluorescence behavior of sensor 3 upon Zn²⁺ complexation. The combination of experimental and computational analyses provides a more complete understanding of the molecular level origin of these unique photophysical properties of this type of chemosensor.     

On the efficiency of VBSCF algorithms,a comment on “An efficient algorithm for energy gradients and orbital optimization in valence bond theory”

We comment on the paper [Song et al., J. Comput. Chem. 2009, 30, 399]. and discuss the efficiency of the orbital optimization and gradient evaluation in the Valence Bond Self Consistent Field (VBSCF) method. We note that Song et al. neglect to properly reference Broer et al., who published an algorithm [Broer and Nieuwpoort, Theor. Chim. Acta 1988, 73, 405] to use a Fock matrix to compute a matrix element between two different determinants, which can be used for an orbital optimization. Further, Song et al. publish a misleading comparison with our VBSCF algorithm [Dijkstra and van Lenthe, J. Chem. Phys. 2000, 113, 2100; van Lenthe et al., Mol. Phys. 1991, 73, 1159] to enable them to favorably compare their algorithm with ours. We give detail timings in terms of different orbital types in the calculation and actual timings for the example cases. © 2012 Wiley Periodicals, Inc.     

Interacting dark energy with inhomogeneous equation of state

We have investigated the model of dark energy interacting with dark matter by choosing inhomogeneous equations of state for the dark energy and a nonlinear interaction term for the underlying interaction. The equations of state have dependencies either on the energy densities, the redshift, the Hubble parameter or the bulk viscosity. We have considered these possibilities and have derived the effective equations of state for the dark energy in each case.     

On tests of independence forr×c Markovian contingency tables

Summary This paper deals with testing the hypothesis of independence of two attributes inr×c Markovian Contingency tables. Likelihood ratio test and χ²-test of the form used in contingency tables are proposed. It is observed that both likelihood ratio criterion and χ²-test lead to the same test statistic in the sense that −2 log λ and χ²-test have asymptotically the same distribution.     

Unbiased segmentation of diffusion-weighted magnetic resonance images of the brain using iterative clustering

Segmentation of diffusion-weighted echo-planar imaging (DW-EPI) is challenging because of concerns regarding spatial resolution and distortion. Methods commonly used require manual input and often need thresholding measures to segment white matter (WM), gray matter (GM) and cerebrospinal fluid (CSF). This may introduce operator bias and misclassification error. When comparing patients with a diffuse disease process-such as multiple sclerosis (MS)--with healthy controls, although information from all images may be biased due to disease effect, this is more so if the data set employed to perform segmentation is also used as a measured outcome for the study, for example, fractional anisotropy maps. Presented in this work is an unbiased method for segmenting DW-EPI data sets using the b=0 and single-shot inversion recovery EPI into WM, GM and CSF. The method employs an iterative clustering technique to account for partial volume effects and signal variation caused by radiofrequency inhomogeneity. The technique is evaluated with both real and synthetic brain data and results compared with statistical parametric mapping (SPM02). With synthetic brain data, where a gold standard of segmentation exists, the presented method showed less misclassification compared to SPM02. The unbiased method proposed may provide a more accurate methodology of segmentation in the analysis of DWI-EPI images in conditions such as MS.