Objects displaced intermittently across the visual field will nonetheless give an illusion of continuous motion [called apparent motion (AM)] under many common conditions. It is believed that form perception is of minor importance in determining AM, and that AM is mediated by motion-sensitive areas in the "where" pathway of the cortex. However, form and motion typically interact in specific ways when natural objects move through the environment. We used functional magnetic resonance imaging to measure cortical activation to longrange AM, compared to short-range AM and flicker, while we varied stability of structural differences between forms. Long-range AM activated the anteriortemporal lobe in the visual ventral pathway, and the response varied according to the form stability. The results suggest that long-range AM is associated with neural systems for form perception.

Three cyclopentadithiophene-difluorophenylene copolymers (named PhF2,3, PhF2,5, and PhF2,6), which differ by the arrangement of fluorines on the phenylene structural unit, were designed and synthesized for the fabrication of organic field-effect transistors (OFETs). Single crystal structures of model compounds representative of the backbone and density functional theory (DFT) were used to estimate the backbone shape for each copolymer. The different substitution arrangements impact the backbone secondary structure through different nonbonding F···H interactions. PhF2,5 and PhF2,6 assumed more linear backbones relative to PhF2,3, which in turn impacts self-assembly and polymer chain alignment on nanogrooved (NG) substrates. A larger improvement of charge carrier mobility for the more linear backbones was achieved when using NG substrates. Among the three polymers, PhF2,6 achieved the highest average field-effect hole mobility (5.1 cm V s). As evidenced by grazing incidence wide-angle X-ray scattering (GIWAXS), thin films of PF2,5 and PF2,6 exhibited a higher degree of anisotropic alignment, relative to the more curved PF2,3 counterpart, consistent with the higher hole mobilities. This work gives insight into how nonbonding interactions can influence charge carrier mobility through changes in secondary structure and suggests that polymers with more linear shapes might be preferred for achieving greater levels of alignment within the confines of a NG environment.

Dental caries is a highly prevalent oral disease that can lead to severe dental damage and may greatly compromise the quality of life of the affected individuals. Previous studies, including those based on 16S rRNA gene, have revealed that the oral microbiota plays a prominent role in development of the disease. But the approach of those studies was limited in analyzing several key microbiome traits, including species- or strain-level composition and functional profile. Here, we performed metagenomic analyses for a cohort of preschool children with or without caries. Our results showed that caries was associated with extensive microbiota differences at various taxonomic and functional levels. Some caries-associated species had not been previously reported, some of which may have significant clinical implications. A microbiome gene catalogue from children with caries was constructed for the first time. The results demonstrated that caries is associated with alterations of the oral microbiome, including changes in microbial composition and metabolic functional profile.

Well-defi ned conjugated oligomers ( Sn ) containing from 1 to 8 units of a tricyclic building block involving a dioctyloxybenzothiadiazole unit with two thienyl side rings ( S1 ) are synthesized by a bottom-up approach. UV-Vis absorption data of solutions show that chain extension produces a narrowing of the HOMO-LUMO gap (Δ E ) to values slightly smaller than that of the parent polymer ( P1 ). Plots of Δ E and of the band gap of fi lms ( E g ) versus the reciprocal chain length show that Δ E and E g converge towards a limit corresponding to an effective conjugation length (ECL) of 7-8 S1 units. UV-Vis absorption and photoluminescence data of solutions and solid fi lms show that chain extension enhances the propensity to inter-chain aggregation. This conclusion is confi rmed by GIXD analyses which reveal that the edge-on orientation of short-chain systems evolves toward a face-on orientation as chain length increases while the π-stacking distance decreases beyond 7 units. The results obtained on solution-processed BHJ solar cells show a progressive improvement of power conversion effi ciency (PCE) with chain extension; however, the convergence limit of PCE remains inferior to that obtained with the polymer. These results are discussed with regard to the role of mono/ polydispersity and chain aggregation.

Membrane-intercalating conjugated oligoelectrolytes (COEs) are emerging as potential alternatives to conventional, yet increasingly ineffective, antibiotics. Three readily accessible COEs, belonging to an unreported series containing a stilbene core, namely D4, D6, and D8, were designed and synthesized so that the hydrophobicity increases with increasing side-chain length. Decreased aqueous solubility correlates with increased uptake by E. coli. The minimum inhibitory concentration (MIC) of D8 is 4 μg mL against both E. coli and E. faecalis, with an effective uptake of 72 %. In contrast, the MIC value of the shortest COE, D4, is 128 μg mL owing to the low cellular uptake of 3 %. These findings demonstrate the application of rational design to generate efficacious antimicrobial COEs that have potential as low-cost antimicrobial agents.

A novel conjugated oligoelectrolyte (COE) material, named S6, is designed to have a lipid‐bilayer stabilizing topology afforded by an extended oligophenylenevinylene backbone. S6 intercalates biological membranes acting as a hydrophobic support for glycerophospholipid acyl chains. Indeed, Escherichia coli treated with S6 exhibits a twofold improvement in butanol tolerance, a relevant feature to achieve within the general context of modifying microorganisms used in biofuel production. Filamentous growth, a morphological stress response to butanol toxicity in E. coli, is observed in untreated cells after incubation with 0.9% butanol (v/v), but is mitigated by S6 treatment. Real‐time fluorescence imaging using giant unilamellar vesicles reveals the extent to which S6 counters membrane instability. Moreover, S6 also reduces butanol‐induced lipopolysaccharide release from the outer membrane to further maintain cell integrity. These findings highlight a deliberate effort in the molecular design of a chain‐elongated COE to stabilize microbial membranes against environmental challenges.

Materials by design are expected to deliver optimized performance for well-defined applications. [1,2] In most cases, the performance of a material depends on the chemical structure and kinetic processes that control the morphology formed, making material design a challenge to directly relate chemical structure to performance. Examples are seen in semiconducting polymers. While the conjugated backbone provides optoelectronic function, side chains, substitution groups, and molecular geometry are factors that dictate how the material will assemble. [3][4][5][6][7][8] When making multicomponents blends, as in the active layer of bulk heterojunction organic photovoltaics (OPV), elucidation of the structure of conjugated polymers and their interactions with fullerenes or other type of acceptors is essential. [9][10][11][12][13] Optimization of a material is, more often than not, a search in a multidimensional space. As seen with the PTBx series of electron donors, the quinoid resonance backbone improved solar light harvesting. [14] Side chain optimization and fluorine atom regioregularity tuning further improved the performance of the materials. [15,16] Donor-acceptor (D-A) conjugated polymers have had tremendous success in generating high power conversion efficiencies in organic solar cells, but required a fine tailoring of the chemical structure to ensure suitable energy levels and to enable intramolecular charge transfer (ICT). [17,18] The D-A conjugated polymers are commonly prepared in a one-pot synthesis through a condensation of A2+B2 intermediates, which inevitably leads to geometric defects if asymmetric monomers are used. Monofluorinated monomers, such as thieno[3,4-b] thiophene (FTT), benzothiadiazole (FBT), and pyridalthiadiazole are well-known high performance units. [16,[19][20][21] However it is essential to be able to minimize or eliminate batch-to-batch variations in the geometry and conformation of the backbone to reliably establish a structure-property relationship, so as to enable the generation of materials by design.Here we present the synthesis of unidirectional, high regioregular conjugated polymers using 5-fluoro-2,1,3-benzothiadiazole (FBT) asymmetric unit. By unidirectional we mean that positioning of the fluorine atom is always at the same position relative to the direction of the chain, which, as will be discussed, orients the dipole in each unit in the same direction. Consequently, the dipole moment would accumulate along the The chemical structure of conjugated polymers plays an important role in determining their physical properties that, in turn, dictates their performance in photovoltaic devices. 5-Fluoro-2,1,3-benzothiadiazole, an asymmetric unit, is incorporated into a thiophene-based polymer backbone to generate a hole conducting polymers with controlled regioregularity. A high dipole moment is seen in regioregular polymers, which have a tighter interchain stacking that promotes the formation of a morphology in bulk heterojunction blends with improved power conversion efficiencie...

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