Organic semiconductors (OSCs) are important active materials for the fabrication of next-generation organic-based electronics. However, the development of n-type OSCs lags behind that of p-type OSCs in terms of charge-carrier mobility and environmental stability. This is due to the absence of molecular designs that satisfy the requirements. The present study describes the design and synthesis of n-type OSCs based on challenging molecular features involving a π-electron core containing electronegative N atoms and substituents. The unique π-electron system simultaneously reinforces both electronic and structural interactions. The current n-type OSCs exhibit high electron mobilities with high reliability, atmospheric stability, and robustness against environmental and heat stresses and are superior to other existing n-type OSCs. This molecular design represents a rational strategy for the development of high-end organic-based electronics.

Optically active acyclic ethynylhelicene oligomers were synthesized in high yields by a two-directional method involving Sonogashira coupling and deprotection. Their CD spectra in chloroform exhibited large differences between the oligomers with less than seven helicenes and their higher homologues, which indicated the formation of helical structures for the latter and random coil structures for the former. The helical heptamer gradually unfolded to a random coil structure in chloroform at room temperature. The unfolding rate was examined by CD in several aromatic solvents as well, and the rate constant k was found to be highly dependent on the type of aromatic substituent: k differed by seven orders of magnitude between iodobenzene and trifluoromethylbenzene. Several features of the rates are notable: The reaction rates in halobenzenes were in the order of iodobenzene > bromobenzene > chlorobenzene > benzene > fluorobenzene > m-difluorobenzene, those in alkylbenzenes were styrene > phenylacetylene > ethylbenzene > toluene > benzene, and those in heteroatom-substituted arenes were thioanisole > benzonitrile > anisole > ethyl benzoate > benzene > trifluoromethylbenzene. The log k values exhibited good correlation with the absolute hardness, eta, of the arenes, and higher unfolding rates were observed in the soft arenes. Vapor pressure osmometry studies indicated that the helical structure of the heptamer is dimeric in benzene, fluorobenzene, and trifluoromethylbenzene, while the random coil structure of the heptamer is monomeric in chloroform and toluene. When a chloroform solution of the random coil structure was concentrated to a small volume, the helical structure could be regenerated.

In the present study, we investigated the direct effect of ATP on cardiac gj by using the whole-cell clamp of paired ventricular myocytes, one of which was perforated to allow intracellular diffusion with extracellular solutions.7 We report here that gj is strongly affected by ATP from 0.1 to 5.0 mM and that this effect is direct and, thus, analogous to the effect reported on other sarcolemmal channels. Materials and Methods PreparationsEnzymatic procedure for the isolation of paired ventricular cells was modified from the method as described by Mitra and Morad.16 Briefly, guinea pigs weighing 150-250 g were killed by an overdose of pentobarbital sodium. The heart was quickly removed, and the aorta was immediately cannulated for Langendorff perfusion. Subsequently, the coronary artery was perfused backward with Ca2`-free Tyrode's solution for 3-4 minutes. Thereafter, the heart was perfused by 50 ml Ca2+-free Tyrode's solution containing 50 mg collagenase (type I, Sigma Chemical, St. Louis, Missouri) and 10 mg protease by guest on

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Cu-deficient layer (CDL) on Cu(In,Ga)Se 2 (CIGS) promotes Cd diffusion from CdS buffer layer and forms a valence band offset (ΔE V ) between CDL and CIGS. We quantitively demonstrate the effects of CDL formation on the performance of CIGS solar cells through experiments and theoretical simulation. To investigate the effects of Cd diffusion and ΔE V by CDL, theoretical analysis was carried out for a CIGS solar cell with a surface layer which simulated the CDL at CdS/CIGS interface. It was revealed that when electron concentration in n-type surface layer is higher than the absolute carrier concentration in CIGS absorber (N D > |N A, CIGS |), open-circuit voltage and fill factor are improved. Additionally, ΔE V ≥ 0.15 eV leads to the highest open-circuit voltage by suppression of interfacial recombination. Transmission electron microscope energy dispersive X-ray spectrometry and scanning spreading resistance microscopy were employed for the same cross section of a CIGS solar cell fabricated by three-stage process. Despite CDL with Cu/(Ga + In) of 0.31 formed on the surface had high Cd contents of 3.4 at%, its carrier concentration of 4.8 × 10 10 cm −3 was lower than that of 10 14 -10 16 cm −3 in grain interior owing to insufficient activation of Cd atoms. These results indicate the effectiveness of ΔE V formation by introducing CDL with low Cu/(Ga + In) of 0.31 to boost CIGS solar cell performance and difficulty in realizing N D > |N A, CIGS | by surface Cd doping.

We used cell pairs electrically coupled with relatively high intercellular resistance to investigate the involvement of calcium current in the origin of the source current during the conduction process of the action potential (AP). Three interventions were used to reduce the calcium current: a specific calcium channel blocker [nifedipine (NIF)], premature stimulation, and increments in the frequency of stimulation of the cell. The ionic membrane current (Iion) after the peak of the AP of the stimulated cell was positive and small when the cell was uncoupled. However, when the stimulated cell was coupled to a cell model or to another cell, Iion during this period became negative and large to supply the coupling current. A rapid early repolarization of the AP occurred in the stimulated cell because of the removal of charge from the stimulated cell. NIF decreased the magnitude of the net negative Iion during this period and caused a more rapid early repolarization in the stimulated cell. NIF increased the delay between the activations of two coupled cells at a given coupling resistance (Rc) but decreased the longest delay that could be produced without conduction failure for a given cell pair. The highest Rc below which conduction of AP occurred was also decreased by NIF. Premature stimulation and an increase of the stimulation frequency also caused an increase in the extent of the early repolarization and increased the delay between two cell activations at a given Rc. Conduction block occurred with sufficient prematurity or at a sufficiently high frequency of stimulation even though activation of the stimulated cell occurred for each stimulus. The Iion that flows during the early plateau phase of the AP in the stimulated cell became negative and significantly large by coupling two cardiac cells together. This current flow is a major component needed to supply the coupling current through the intercellular resistance. The decrease of calcium current caused a decrease in the magnitude of this net inward ionic current, resulting in an increase of the rate of early repolarization and an increase in the conduction delay between two cells at a given Rc. These results suggest the involvement of calcium current in the conduction process when cells are coupled at relatively high Rc.

Background/AimTo train and validate the prediction performance of the deep learning (DL) model to predict visual field (VF) in central 10° from spectral domain optical coherence tomography (SD-OCT).MethodsThis multicentre, cross-sectional study included paired Humphrey field analyser (HFA) 10-2 VF and SD-OCT measurements from 591 eyes of 347 patients with open-angle glaucoma (OAG) or normal subjects for the training data set. We trained a convolutional neural network (CNN) for predicting VF threshold (TH) sensitivity values from the thickness of the three macular layers: retinal nerve fibre layer, ganglion cell layer+inner plexiform layer and outer segment+retinal pigment epithelium. We implemented pattern-based regularisation on top of CNN to avoid overfitting. Using an external testing data set of 160 eyes of 131 patients with OAG, the prediction performance (absolute error (AE) and R2 between predicted and actual TH values) was calculated for (1) mean TH in whole VF and (2) each TH of 68 points. For comparison, we trained support vector machine (SVM) and multiple linear regression (MLR).ResultsAE of whole VF with CNN was 2.84±2.98 (mean±SD) dB, significantly smaller than those with SVM (5.65±5.12 dB) and MLR (6.96±5.38 dB) (all, p<0.001). Mean of point-wise mean AE with CNN was 5.47±3.05 dB, significantly smaller than those with SVM (7.96±4.63 dB) and MLR (11.71±4.15 dB) (all, p<0.001). R2 with CNN was 0.74 for the mean TH of whole VF, and 0.44±0.24 for the overall 68 points.ConclusionDL model showed considerably accurate prediction of HFA 10-2 VF from SD-OCT.

Two compounds with two hexa(ethynylhelicene) parts connected by a flexible hexadecamethylene and a rigid butadiyne linker were synthesized. The 1H NMR spectroscopic and CD analyses and vapor-pressure osmometry (VPO) of these two compounds revealed intramolecular double-helix formation. Upon heating a 5-microM solution in toluene, the double-helix structure unfolded to form a random coil, and on cooling it folded again into a double helix. The thermodynamic stabilities of both structures were dependent on temperature, and the structural change in both compounds is due to the large enthalpies and entropies under equilibrium. The rate constants of their unfolding were obtained by assuming a pseudo-first-order reaction; the compound with a rigid linker unfolded slower than that with a flexible linker. The former has a larger activation energy, and its double-helix and random-coil conformers were separated by chromatography. The rate of folding was also faster for the flexible-linker compound with larger activation energy. The rate constants for the folding of both compounds slightly decreased with increasing temperature, which was ascribed to the presence of exothermic pre-equilibrium and rate-determining steps. The folding was markedly accelerated with increasing random-coil concentration, which suggests the involvement of self-catalysis. A mechanism of folding was proposed. The involvement of different mechanisms of folding and unfolding was suggested by the kinetic studies, and it was confirmed by the presence of hysteresis in the melting profiles. The difference in linker structure also affected the thermal-switching profiles of the double-helix-random-coil structural changes.