Effect of Fluorine Substitution on Photovoltaic Properties of Benzothiadiazole–Carbazole Alternating Copolymers

To investigate the effect of fluorine substitution on molecular and film structures, optical, electrochemical, and photovoltaic properties of a moderate bandgap polymer, poly­(2,7-carbazole-<i>alt</i>-dithienylbenzothiadiazole) (PCDTBT) with deep HOMO energy level, a fluorinated analogue of PCDTBT (i.e., PCDTBT-F) has been developed for the first time by replacing two hydrogen atoms on benzothiadiazole (BT) units with two fluorine atoms. An analogous polymer, PCBBBT-F with additional hexylthiophenes between the thiophene and carbazole of PCDTBT-F, has also been prepared to overcome the poor solubility of PCDTBT-F. The PCBBBT-F film showed wide absorption bands in UV and visible regions with an optical bandgap of 1.82 eV that is smaller than that of PCDTBT (1.89 eV), whereas the film of PCDTBT-F exhibited blue-shifted absorption with a bandgap of 1.96 eV due to the low molecular weight arising from the deficient solubility. The HOMO energy level of PCDTBT-F is lower than that of PCDTBT, owing to the electron-withdrawing fluorination of the BT unit, whereas PCBBBT-F exhibited a higher HOMO level than PCDTBT, implying that the additional incorporation of electron-donating hexylthiophenes negated the fluorination effect. A bulk heterojunction (BHJ) polymer solar cell (PSC) that employed PCDTBT-F or PCBBBT-F as an electron donor and a fullerene derivative [70]­PCBM as an electron acceptor yielded lower power conversion efficiencies of 1.29 and 1.98%, respectively, than that of PCDTBT (6.16%) due to the unfavorable film structures of PCDTBT-F:[70]­PCBM resulting from the poor solubility and low molecular weight, as well as low crystallinities and limited exciton lifetimes, of the fluorinated polymers. These results provide valuable information on the elaborate design of PCDTBT-based polymers for the PSC applications

An Unexpected Apparition—Or Old Valves Die Hard

An Unexpected Apparition—Or Old Valves Die Har

SKF38393 increases the repertoires of SW-relevant LFP spectra patterns.

<p><b>A.</b> Representative fast Fourier transform spectra of 136 SW events during the pre-treatment baseline period of 3 min. <b>B.</b> The correlation matrix obtained from the 136 SWs was sorted by the affinity propagation and was clustered into 14 SW subgroups. <b>C.</b> The mean numbers of the SW subgroups before and after administration with control aCSF (left) and SKF38393 (right). Each gray dataset indicates a single slice. **<i>P</i> = 0.0059, <i>t</i>₇ = 3.38, paired <i>t</i>-test. Data are the means ± SEMs of 8 slices.</p

Neuronal activities during SWs are optically imaged.

<p><b>A.</b> A confocal image of the CA1 stratum pyramidale in an OGB1-loaded slice. The location of an LFP electrode is shown by the white lines. <b>B.</b> Example of calcium transients from 9 cells and LFP trace, before (left) and after (right) SKF38393 application. <b>C.</b> Simultaneous cell-attached recording and calcium imaging. Numbers of spikes are represented above each spike. Spike timimgs detected from the calcium trace are shown by bars below the trace. <b>D.</b> A peri-SW time histogram of calcium events. Data are the means ± SEMs from 8 slices, including a total of 7,709 calcium events emitted by 199 cells. The time period between −200 ms and 50 ms relative to the SW peak was defined as a SW window (shadow). Calcium events during this time window are regarded as SW-locked activities. <b>E.</b> Representative raster plots of calcium events 0–3 min before (top) and 15–18 min after (bottom) the bath application of 30 µM SKF38393. Green or orange bars above each raster plot indicate the time stamps of individual SW events. Thick dots in the rastergram indicate SW-locked activities. <b>F–H.</b> Comparisons of peri-SW time histograms from each slices in 3 parameters; Time lag of the histogram peak from the SW peak (F), skewness of the histograms (G) and kurtosis of the histograms (H). <b>I.</b> Comparisons of the co-activation probability of any given pairs of cells that participated at least once in SW before (left) and after (right) the drug application. Each dot indicates a single neuron pair.</p

Putative pyramidal neurons are more affected by SKF38393 than putative interneurons.

<p><b>A.</b> The mean SW-locked probability of cells with the top 20% SW-locked probability (left) and that of the bottom 80% SW-locked probability (right). <b>B.</b> The mean amplitude of calcium transients of the top 20% SW-locking cells (left) and that of the bottom 80% cells (right; *<i>P</i> = 0.016, <i>t</i>₇ = 3.14, paired <i>t</i>-test). <b>C.</b> A Venn diagram of the population of cells that participated in at least one SW event during the 3-min periods before and after the application 30 µM SKF38393 for the top 20% SW-locking cells (left) and the bottom 80% cells (right).</p

D₁/D₅ receptor activation is responsible for dopamine induced SW facilitation.

<p><b>A.</b> Time course of the percentage of the frequency of SW events relative to the mean value during the pre-application period while the slices were perfused with 0.1 µM SCH23390, a D₁/D₅ receptor antagonist, and 1 µM sulpiride, a D₂ receptor antagonist, from time 0–45 min. <b>B–C.</b> The mean SW event frequency (B) and the mean SW amplitude (C) at time 30–35 min. <b>D.</b> Slices were perfused with 1 µM dopamine for 1 min at time 0 in the continuous presence of 0.1 µM SCH23390 or 1 µM sulpiride. <b>E–F.</b> The mean SW event frequency (E) and the mean SW amplitude (F) at time 30–35 min. *<i>P</i> = 0.032, <i>t</i>₆ = 2.78, *<i>P</i> = 0.035, <i>t</i>₆ = 2.71, paired <i>t</i>-test <i>versus</i> the −5-to-0 min period. Data are the means ± SEMs of 7 and 6 slices from 4 and 3 mice, respectively. <b>G.</b> Slices were perfused with 30 µM SKF38393 at time 0 in the absence (orange) and the continuous presence (light blue) of 0.1 µM SCH23390, a D₁/D₅ receptor antagonist. <b>H–I.</b> The mean SW event frequency (H) and the mean SW amplitude (I) at time 30–35 min. **<i>P</i> = 0.0017, <i>t</i>₁₂ = 4.02 (H); *<i>P</i> = 0.017, <i>t</i>₁₂ = 2.78 (I), paired <i>t</i>-test <i>versus</i> the −5-to-0 min period. Data are the means ± SEMs of 13 and 5 slices from 10 and 3 mice, respectively. <b>J.</b> While fEPSPs evoked by field stimulation of Schaffer collaterals were recorded from CA1 stratum radiatum, slices were perfused with 30 µM SKF38393 for 1 min at time 0. Time changes in fEPSP amplitudes (left) and slopes (right) are plotted as mean ± SEMs of 3 slices from 3 mice. The insets indicate example traces at two time points.</p

SKF38393 preserves SWs-participating neurons.

<p><b>A.</b> A Venn diagram of the population of cells that participated in at least one SW event during the 3-min periods before and after the application of control aCSF (left) or 30 µM SKF38393 (right). The values indicate the percentage of cells involved in the corresponding states to the total cells. The two populations overlapped significantly. Control: <i>P</i> = 1.85×10⁻⁵<i>versus</i> the chance level (21.2%), <i>Z</i> = 4.28; SKF38393: <i>P</i> = 1.62×10⁻⁸ versus the chance level (16.9%), <i>Z</i> = 5.65, Z-test for a proportion. <b>B.</b> Relationship of the frequencies of SW-locked activities of individual neurons before and after control aCSF (left) or 30 µM SKF38393 (right) administration. Each dot indicates a single neuron. Control: <i>R</i>² = 0.57, <i>P</i> = 5.0×10⁻⁴⁸, <i>t</i>₂₅₁ = 18.3; SKF38393: <i>R</i>² = 0.64, <i>P</i> = 3.7×10⁻⁸³, <i>t</i>₃₆₄ = 25.5, <i>t</i>-test of a correlation coefficient. <b>C.</b> The mean percentage of cells that participated in a single SW event to the total cells before and after aCSF or SKF38393 administration. Each gray dataset represents a single slice. Control: <i>P</i> = 0.93, <i>t</i>₄ = 0.098; SKF38393: <i>P</i> = 0.25, <i>t</i>₇ = 1.23, paired <i>t</i>-test. Data are the means ± SEMs of 5 or 8 slices. <b>D.</b> Comparison of the mean amplitudes of SW-locked calcium transients from 150 and 199 SW participants before and after the drug application. Control: <i>R</i>² = 0.091, SKF38393, <i>R</i>² = 0.00025, <i>P</i> = 0.13, <i>Z</i> = 1.53, <i>Z</i>-test for two correlation coefficients. Each dot indicates a single neuron.</p

SKF38393 increases the repertoires of SW-relevant firing patterns.

<p><b>A.</b> Representative spatiotemporal patterns of SW-locked activities in 136 SW events during the observation period of 3 min. <b>B.</b> The correlation coefficients between patterns of SW-participating neurons were calculated for all possible SW pairs. The representative correlation matrix was obtained from 136 SWs shown in A. <b>C.</b> Cumulative distribution of the correlation coefficients before (green) and after (orange) perfusion with control aCSF [left, 795 SW events (before) and 1,076 (after) from 8 slices] and SKF38393 [right, 795 SW events (before) and 1,076 (after) from 8 slices]. <b>D.</b> The affinity propagation algorithm separated 136 SW events in B. into 26 SW subgroups, indicated by different colors. <b>E.</b> The mean number of the SW subgroups before and after the application of control aCSF (left) and SKF38393 (right). Each gray dataset indicates a single slice. *<i>P</i> = 0.030, <i>t</i>₇ = 2.25, paired <i>t</i>-test. Data are the means ± SEMs of 5 or 8 slices. <b>F.</b> The same analysis as E was repeated a time window between −50 and +50 ms relative to the SW peak (left). The mean numbers of the SW subgroups before and after the application of control aCSF (left) and SKF38393 (right) are shown in the bar graph. *<i>P</i> = 0.036, <i>t</i>₇ = 2.12, paired <i>t</i>-test. Data are the means ± SEMs of 8 slices. <b>G.</b> The relationship between the number of SW-participating neurons and of SW patterns. Data obtained from the same slice are connected with black line. Before (green); <i>R</i>² = 0.21, <i>P</i> = 0.24. After (orange); <i>R</i>² = 8.3×10⁻⁴, <i>P</i> = 0.95.</p

REE patterns of distribution coefficients (<i>K_d</i>, L/g) for REE adsorption.

<p>(a) salmon milt (pH 4, 3, and 2), bacteria (<i>B. subtilis</i>) <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0114858#pone.0114858-Takahashi2" target="_blank">[10]</a>, and DNA-filter paper hybrid <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0114858#pone.0114858-Takahashi1" target="_blank">[9]</a>; (b) CP, CMC, and Ln-resin <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0114858#pone.0114858-Takahashi1" target="_blank">[9]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0114858#pone.0114858-Takahashi2" target="_blank">[10]</a>.</p

EXAFS parameters for Dy and Lu species adsorbed on salmon milt and reference materials (CN, coordination number; R, interatomic distance; ΔE0, threshold E0 shift; σ, Debye-Waller factor; least squares precisions are given to each value).

a<p>Accuracy in the fitted parameters were estimated to be generally ±0.02 Å for R, ±20% for CN, and 20% for σ. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0114858#pone.0114858-Taylor1" target="_blank">[2]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0114858#pone.0114858-ODay1" target="_blank">[31]</a>.</p>b<p>The numbers with * were fixed during the fitting of EXAFS spectra.</p><p>EXAFS parameters for Dy and Lu species adsorbed on salmon milt and reference materials (CN, coordination number; R, interatomic distance; ΔE0, threshold E0 shift; σ, Debye-Waller factor; least squares precisions are given to each value).</p