Exploring water binding motifs to an excess electron via X2(-)(H2O) [X = O, F

X(2)(-)(H(2)O) [X = O, F] is utilized to explore water binding motifs to an excess electron via ab initio calculations at the MP4(SDQ)/aug-cc-pVDZ + diffs(2s2p,2s2p) level of theory. X(2)(-)(H(2)O) can be regarded as a water molecule that binds to an excess electron, the distribution of which is gauged by X(2). By varying the interatomic distance of X(2), r(X1-X2), the distribution of the excess electron is altered, and the water binding motifs to the excess electron is then examined. Depending on r(X1-X2), both binding motifs of C(s) and C(2v) forms are found with a critical distance of ～1.37 ? and ～1.71 ? for O(2)(-)(H(2)O) and F(2)(-)(H(2)O), respectively. The energetic and geometrical features of O(2)(-)(H(2)O) and F(2)(-)(H(2)O) are compared. In addition, various electronic properties of X(2)(-)(H(2)O) are examined. For both O(2)(-)(H(2)O) and F(2)(-)(H(2)O), the C(s) binding motif appears to prevail at a compact distribution of the excess electron. However, when the electron is diffuse, characterized by the radius of gyration in the direction of the X(2) bond axis with a threshold of ～0.84 ?, the C(2v) binding motif is formed.     

Morphology evolution of polypropylene in immiscible polymer blends for fabrication of nanofibers

Immiscible blends of cellulose acetate butyrate (CAB) and isotactic polypropylenes (iPPs) with different melting index were extruded through a two‐strand rod die. The extrudates were hot‐drawn at the die exit at different draw ratios by controlling the drawing speed. The morphologies of iPP fibers extracted from the as‐obtained extrudates after removal of CAB by acetone were investigated by scanning electron microscopy. The influences of draw ratio, viscosity ratio, and composition ratio of CAB/iPP on the morphology evolution of iPP phase into nanofibers in the immiscible blends were studied. It was found that the thermoplastic iPP nanofibers were formed from the elongation of iPP ellipsoids, end‐to‐end merging of elongated iPP microfibers, and the size decrease of iPP microfibers in the processes of extrusion and drawing. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 921–931, 2010     

Exploration of Potential Tumor Markers for Lung Adenocarcinomas by Two‐Dimensional Gel Electrophoresis Coupled with Nano‐LC/MS/MS

To explore the potential tumor markers for lung adenocarcinoma, two‐dimensional gel electrophoresis (2DE) coupled with nano‐LC/MS/MS was used to analyze the differentially expressed proteins in 10 surgical resected lung adenocarcinoma tissues. 16 proteins were significantly different between the cancer tissue and adjacent normal tissue. Galectin‐1, peroxiredoxin II (Prx II), proapolipoprotein, glyceraldehyde‐3‐phosphate dehydrogenase (GAPDH), aldolase A, enolase 1, neuropolypeptide h3, Prx V, cyclophilin A, vimentin, protein disulfide isomerase (PDI), tropomyosin 3 (TPM 3), glutathione S‐transferase Pi (GST‐Pi), manganese superoxide dismutase (MnSOD), and cofilin 1 were up‐regulated in the cancer tissue. On the other hand, profilin was down‐regulated in the cancer tissue. Among these proteins, six proteins were validated by Western blot analysis. The identified proteins contributing to the spectrum of cancer progression may be used as potential diagnostic biomarkers for lung adenocarcinomas.     

A low cost and simple configuration of multifunctional multichannel analyzer based on a personal computer

A low cost and simple configuration of multifunctional MCA based on a personal computer is described. It can be used as a spectrum multiscaling analyzer, multi-input pulse height analyzer and dual parameter MCA. It can also be used in a master-slave ADC configuration in order to cut down the dead time of the system. All the functions can be performed by loading the corresponding programs without altering the hardware configuration. Interrupt service routines are used to handle the digital data converted by ADC. A dead time counter is also provided to record the dead time profile by measuring the ADC busy time.     

Alkyne-mediated domino hydroformylation/double cyclization: mechanistic insight and synthesis of (±)-tashiromine

A novel domino reaction, alkyne-mediated domino hydroformylation/double cyclization, has been developed for rapid preparation of indolizidine type alkaloids. DFT calculations were applied for rationales of reactivity and selectivity. A concise synthesis of tashiromine as the application of the methodology is also reported.     

Establishment of an ectopically expressed and functional PRMT1 for proteomic analysis of arginine-methylated proteins

Protein arginine methylation, catalyzed by protein arginine methyltransferases (PRMTs), plays crucial roles in a variety of cellular processes. Mammalian PRMT1 exists in a large protein complex in cells, which has been implied in modulating the regulatory and catalytic properties of this enzyme. Establishment of a mammalian comparative approach will help to identify putative substrates of PRMT1 in an authentic condition. Here, we showed that ectopically expressed PRMT1 in mammalian HEK293 cells not only exhibited catalytic properties comparable to the endogenous enzyme but also existed in a functional complex together with endogenous PRMT1 and thus functioned as an endogenous counterpart. In addition, the measured methylation level of cellular proteins using a tritium-labeled methyl donor was accordingly enhanced upon ectopic expression of PRMT1. Subsequent proteomic analysis with such PRMT1-expressing cells allowed us to identify several known and putative methylated proteins. In vitro methylation of selected proteins, eukaryotic translation initiation factor 4A-I and vimentin, by cellular PRMT1 was shown. Together, we have demonstrated the functional equivalence of ectopically expressed PRMT1 in HEK293 cells and its application to systematically identify the substrate proteins in a mammalian cell context.     

Proteomics analysis of in vitro protein methylation during Src-induced transformation

Src, a nonreceptor tyrosine kinase, was the first oncogene identified from an oncogenic virus. Mechanistic studies of Src-induced transformations aid in understanding the pathologic processes underlying tumorigenesis and may provide new strategies for cancer therapy. Although several pathways and protein modifications are reportedly involved in Src-induced transformation, the detailed mechanisms of their regulation remain unclear. Protein methylation is an important PTM that is widely involved in cellular physiology. In this study, we determined if protein methylation was involved in Src activation and which methylated proteins were associated with this activity. Using in vitro methylation and 2-DE analysis of viral Src (v-Src)-transformed rat kidney epithelial cells (RK3E), several known and novel methylated proteins were identified based on their changes in methylation signal intensity upon transformation. Among these, elongation factor 2 (EF-2), heterogeneous nuclear ribonucleoprotein K (hnRNP K), and β-tubulin protein expressions remained unchanged, indicating that their altered methylation levels were due to Src activation. In addition, the altered expression of β-actin, vimentin, and protein phosphatase 2, catalytic subunit (PPP2C) as well as protein phosphatase 2, catalytic subunit methylation were also confirmed in RK3E cells transformed with a human oncogenic Src mutant (Src531), supporting their association with Src-induced transformation in human cancer. Together, we showed putative involvement of protein methylation in Src activation and our identification of methylated proteins provides important targets for extensively studying Src-induced transformations.     

Syntheses and Characterization of Manganese-Tellurolate Complexes by Using Chelating Metalloligand cis-[Mn(Co)4(TePh)2]− and Potential Electrophilic TeMe+ Reagent

The cis-[Mn(CO)₄(TePh)₂]^?, similar to bidentate ligand PhTe(CH₂)₃TePh, acts as a “chelating metalloligand” for the synthesis of metallic tellurolate compounds. The reaction of cis[Mn(CO)₄(TePh)₂]^? with BrMn(CO)₅ in THF leads to a mixture of products[(CO)₃,BrMn(μ-TePh)₂Mn(CO)₄]^? (1) and Mn₂(μ-TePh)₂(CO)_g (2). Complex 1 crystallizes in the triclinic space group Pl? with a = 11.309(3) Å, b = 14.780(5) Å, c = 19.212(6) Å, a = 76.05(3)° β = 72.31(3)°, γ = 70.41(3)° V = 2848(2) Å₃, Z = 2. Final R = 0.034 and R_w = 0.035 resulting from refinement of 10021 total reflections with 677 parameters, Dropwise addition of (MeTe)₂ to a solution of [Me₃O][BF₄] in CH₃CN leads to formation of [Me₂TeTeMe][BF₄], a potential MeTe⁺ donor ligand. In contrast to oxidative addition of diphenyl ditelluride to [Mn(CO)s]^? to give cis-[Mn(CO)₄(TePh)₂]^? which was thermally transformed into [(CO)₃Mn(μ-TePh)₃Mn(CO)₃]^?, reaction of [Mn(CO)₅]^?with [Me₂TeTeMe]⁺ proceeded to give the monomeric species MeTeMn(CO)₅ as initial product which was then dimerized into Mn₂(μ-TeMe)₂(CO)_g (4).     

Electron- and Hole-Doping Effects in Manganites Studied by X-Ray Absorption Spectroscopy

We investigate the electronic structures of hole-doped, La_0.7Ca_0.3MnO₃, and electron-doped, La_0.7Ce_0.3MnO₃, manganites by x-ray absorption near edge structure (XANES) spectroscopy at the O and Mn K-edges. While, the O K-edge XANES results indicate that Ca and Ce doping induce holes in O 2p derived states, the Mn K-edge XANES do not give any evidence for creation of the Mn⁴⁺ (or Mn²⁺) ions by Ca (or Ce) dopants. Such results further questions the validity of double exchange mechanism in understanding the anomalous properties of manganites.