source materials were heated to between 60 and 200 C. The pressure in the source vessels was between 80 and 196 hPa. The carrier gas was Ar and the flow rate was in the range 70±300 sccm, depending on the source materials, which were loaded individually into the source vessels. The pipes connected to the reactor were heated to above 200 C in order to avoid vapor condensation. Oxygen was supplied to the reactor at 36 hPa and the total pressure in the reactor was 65 hPa. The deposition temperature was 800 C. The as-prepared thin films had a cation composition of Bi/Sr/Ca/Cu = 1:1:1:(1.5±1.7). The composition and thickness of the thin films were determined by inductively coupled plasma atomic emission spectroscopy (ICP-AES) (SPS 7700, Seiko Instruments Inc.). X-ray diffraction patterns (D500, Siemens) have shown that that films were epitaxial, c-axis aligned, and formed from the Bi 2 Sr 2 Ca 2 Cu 3 O 10±x phase. The morphology of the thin films was inspected by optical microscopy on large areas, and by atomic force microscopy (AFM) (SPA 300, Seiko Instruments Inc.) locally. The superconductivity of the thin films was checked by the standard four-probe method.

One of the most inspiring and puzzling developments in the organic electronics community in the last few years has been the emergence of solution-processable semiconducting polymers that lack significant long-range order but outperform the best, high-mobility, ordered semiconducting polymers to date. Here we provide new insights into the charge-transport mechanism in semiconducting polymers and offer new molecular design guidelines by examining a state-of-the-art indacenodithiophene-benzothiadiazole copolymer having field-effect mobility of up to 3.6 cm 2 V À 1 s À 1 with a combination of diffraction and polarizing spectroscopic techniques. Our results reveal that its conjugated planes exhibit a common, comprehensive orientation in both the non-crystalline regions and the ordered crystallites, which is likely to originate from its superior backbone rigidity. We argue that charge transport in high-mobility semiconducting polymers is quasi one-dimensional, that is, predominantly occurring along the backbone, and requires only occasional intermolecular hopping through short p-stacking bridges.

Two novel indacenodithiophene (IDT) based donor–acceptor conjugated polymers for use in organic field effect transistors and photovoltaic devices are synthesized and characterized. The effect of inclusion of two fluorine atoms on the acceptor portion of the polymer is thoroughly investigated via a range of techniques. The inductively withdrawing and mesomerically donating properties of the fluorine atoms result in a decrease of the highest occupied molecular orbital (HOMO), with little effect on the lowest unoccupied molecular orbital (LUMO) as demonstrated through density functional theory (DFT) analysis. Inclusion of fluorine atoms also leads to a potentially more planar backbone through inter and intrachain interactions. Use of the novel materials in organic field effect transistor (OFET) and organic photovoltaic (OPV) devices leads to high mobilities around 0.1 cm2/(V s) and solar cell efficiencies around 4.5%.

Smoothing splines via the penalized least squares method provide versatile and effective nonparametric models for regression with Gaussian responses. The computation of smoothing splines is generally of the order "O"("n"-super-3), "n" being the sample size, which severely limits its practical applicability. We study more scalable computation of smoothing spline regression via certain low dimensional approximations that are asymptotically as efficient. A simple algorithm is presented and the Bayes model that is associated with the approximations is derived, with the latter guiding the porting of Bayesian confidence intervals. The practical choice of the dimension of the approximating space is determined through simulation studies, and empirical comparisons of the approximations with the exact solution are presented. Also evaluated is a simple modification of the generalized cross-validation method for smoothing parameter selection, which to a large extent fixes the occasional undersmoothing problem that is suffered by generalized cross-validation. Copyright 2004 Royal Statistical Society.

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This study focuses on the ironic situation in which news is more available than ever but people are becoming overwhelmed and thus avoid it. A theoretical model is suggested to investigate the relationships between perceived news overload and its cognitive and attitudinal consequences among South Korean Internet users. A structural model reveals that perceived news overload induced news avoidance by increasing news fatigue and news analysis paralysis. Furthermore, this study finds evidence that news consumers are willing to use news curation services to alleviate news avoidance and thus stay informed.

This study attempts to identify the predictors of e-book reader diffusion with regard to consumer awareness, interest, and intention to use. Specifically, it assesses the relative influence of demographics, media usage/ownership, and personal traits/perception variables in the technology-adoption process. A national consumer survey conducted in South Korea, a leading country in the proliferation of e-book use, found that e-book reader awareness, interest, and adoption intention correlated positively with age, education, income, perceived need for print media, digital media ownership, personal innovativeness, and the perceived attributes of e-book readers. Regarding the relative effects of variable blocks, the most influential factors in predicting e-book reader awareness, e-book reader interest, and intention to use were demographics, personal innovativeness, and the perceived attributes of e-book readers, respectively.

Polymerases have a structurally highly conserved negatively charged amino acid motif that is strictly required for Mg 2+ cation-dependent catalytic incorporation of (d)NTP nucleotides into nucleic acids. Based on these characteristics, a nucleoside monophosphonate scaffold, α-carboxy nucleoside phosphonate (α-CNP), was designed that is recognized by a variety of polymerases. Kinetic, biochemical, and crystallographic studies with HIV-1 reverse transcriptase revealed that α-CNPs mimic the dNTP binding through a carboxylate oxygen, two phosphonate oxygens, and base-pairing with the template. In particular, the carboxyl oxygen of the α-CNP acts as the potential equivalent of the α-phosphate oxygen of dNTPs and two oxygens of the phosphonate group of the α-CNP chelate Mg 2+ , mimicking the chelation by the β-and γ-phosphate oxygens of dNTPs. α-CNPs (i) do not require metabolic activation (phosphorylation), (ii) bind directly to the substrate-binding site, (iii) chelate one of the two active site Mg 2+ ions, and (iv) reversibly inhibit the polymerase catalytic activity without being incorporated into nucleic acids. In addition, α-CNPs were also found to selectively interact with regulatory (i.e., allosteric) Mg 2+ -dNTP-binding sites of nucleos(t)ide-metabolizing enzymes susceptible to metabolic regulation. α-CNPs represent an entirely novel and broad technological platform for the development of specific substrate active-or regulatory-site inhibitors with therapeutic potential. The polymerization of nucleotides by Escherichia coli DNA polymerase I represents a general model for catalytic action of nucleic acid polymerases (SI Appendix, Fig. S1) (1, 2). According to this model, there is a universal role for the Mg 2+ cation to interact with three phosphate oxygens of dNTP. The highly conserved consensus motifs in every polymerase active site consist of either aspartate or glutamate residues that chelate Mg 2+ through three additional coordination bonds during polymerization (2, 3). The crucial role of the metal cofactor and structurally conserved active site architecture in polymerases has also been demonstrated by validating Mg 2+ as a target for the design of antiviral drugs, not only against HIV RT but also, among others, against HIV integrase, HIV ribonuclease H (RNase H), and influenza-encoded endonuclease (4, 5). Hence, it should be feasible to design a universal but simplified (d)NTP mimic that binds efficiently to a wide variety of DNA/RNA polymerases.It was hypothesized that a universal nucleoside triphosphate mimic should contain three major indispensable entities: (i) a nucleobase part (i.e., to achieve optimal Watson-Crick basepairing with the template overhang), (ii) a replacement of the triphosphate moiety that should enable efficient Mg 2+ -directed coordination, and (iii) a variable linker between the nucleobase and the modified triphosphate to mimic the pentose entity present in natural (d)NTPs. For the triphosphate part, we chose an α-carboxy phosphonate entity that is chemically stable in physiolog...