Quantitative and time-course analysis of microbial degradation of 1H,1H,2H,2H,8H,8H-perfluorododecanol in activated sludge.

A methylene group in the fluorinated carbon backbone of 1H,1H,2H,2H,8H,8H-perfluorododecanol (degradable telomer fluoroalcohol, DTFA) renders the molecule cleavable by microbial degradation into two fluorinated carboxylic acids. Several biodegradation products of DTFA are known, but their rates of conversion and fates in the environment have not been determined. We used liquid chromatography coupled with tandem mass spectrometry (LC/MS/MS) to quantitatively investigate DTFA biodegradation by the microbial community in activated sludge in polyethylene terephthalate (PET) flasks, which we also determined here showed least adsorption of DTFA. A reduction in DTFA concentration in the medium was accompanied by rapid increases in the concentrations of 2H,2H,8H,8H-perfluorododecanoic acid (2H,2H,8H,8H-PFDoA), 2H,8H,8H-2-perfluorododecenoic acid (2H,8H,8H-2-PFUDoA), and 2H,2H,8H-7-perfluorododecenoic acid and 2H,2H,8H-8-perfluorododecenoic acid (2H,2H,8H-7-PFUDoA/2H,2H,8H-8-PFUDoA), which were in turn followed by an increase in 6H,6H-perfluorodecanoic acid (6H,6H-PFDeA) concentration, and decreases in 2H,2H,8H,8H-PFDoA, 2H,8H,8H-2-PFUDoA, and 2H,2H,8H-7-PFUDoA/2H,2H,8H-8-PFUDoA concentrations. Accumulation of perfluorobutanoic acid (PFBA), a presumed end product of DTFA degradation, was also detected. Our quantitative and time-course study of the concentrations of these compounds reveals main routes of DTFA biodegradation, and the presence of new biodegradation pathways.

Substrate-oriented nanorod scaffolds in polymer-fullerene bulk heterojunction solar cells.

The use of a p-type inorganic semiconductor to form a nanorod scaffold within a polymer-fullerene bulk heterojunction solar cell is reported. The performance of this cell is compared to those made of the commonly used n-type scaffold of ZnO, which has been reported many times in the literature. The scaffold is designed to improve charge-carrier collection by increased mobility in thicker samples. Observations show that generally the device performance shows a negative correlation to nanorod length. By using CuSCN as a p-type inorganic scaffold, a very similar trend is observed.

Growth Suppression of a Robust Bacterium Methylobacterium extorquens by Porous Materials with Oxygen Functional Groups.

Suppressing the growth of Methylobacterium species without the use of toxic chemicals has been a challenging task owing to their robustness against previous antimicrobial techniques. In this work, we prepared porous materials with various numbers and types of oxygen functional groups and investigated their ability to suppress the growth of Methylobacterium extorquens. It turned out that the number and type of oxygen functional groups in the porous materials greatly affected the growth of the bacterium. Three porous materials (resorcinol-formaldehyde gel (RF), hydrothermally treated RF (RFH), and Wakkanai siliceous shale (WS)) were tested, and RF exhibited the best performance in suppressing the growth of the bacterium. This performance is possibly due to abundant phenolic groups in the porous material.

Control of Molecular Orientation in Organic Semiconductors Using Weak Iodine-Iodine Interactions.

Controlling the molecular orientation of materials is a key issue for improving the performance of organic semiconductor devices. Herein, we demonstrate the structure-property relationships of iodinated and noniodinated molecules based on an asymmetric thienoacene framework. The noniodinated molecule formed an antiparallel slip-stack structure with small orbital overlap between molecules. In contrast, the iodinated molecule formed a head-to-head layered-herringbone structure, and as a result, the transfer integrals became larger and the hole mobility increased significantly compared with the noniodinated material. The iodinated molecule was made into a stable and solution-processable p-type organic semiconductor with a mobility of 2.2 cm2 V-1 s-1, which was 2 orders of magnitude higher than that of the noniodinated molecule. This study reveals that controlling molecular orientations using iodine-iodine interactions is a promising strategy for accelerating the development of organic semiconductor materials.

A Fabry-Pérot cavity coupled surface plasmon photodiode for electrical biomolecular sensing.

Surface plasmon resonance is a well-established technology for real-time highly sensitive label-free detection and measurement of binding kinetics between biological samples. A common drawback, however, of surface plasmon resonance detection is the necessity for far field angular resolved measurement of specular reflection, which increases the size as well as requiring precise calibration of the optical apparatus. Here we present an alternative optoelectronic approach in which the plasmonic sensor is integrated within a photovoltaic cell. Incident light generates an electronic signal that is sensitive to the refractive index of a solution via interaction with the plasmon. The photogenerated current is enhanced due to the coupling of the plasmon mode with Fabry-Pérot modes in the absorbing layer of the photovoltaic cell. The near field electrical detection of surface plasmon resonance we demonstrate will enable a next generation of cheap, compact and high throughput biosensors.

Current Contributions of Organofluorine Compounds to the Agrochemical Industry.

Currently, more than 1,200 agrochemicals are listed and many of these are regularly used by farmers to generate the food supply to support the expanding global population. However, resistance to pesticides is an ever more frequently occurring phenomenon, and thus, a continuous supply of novel agrochemicals with high efficiency, selectivity, and low toxicity is required. Moreover, the demand for a more sustainable society, by reducing the risk chemicals pose to human health and by minimizing their environmental footprint, renders the development of novel agrochemicals an ever more challenging undertaking. In the last two decades, fluoro-chemicals have been associated with significant advances in the agrochemical development process. We herein analyze the contribution that organofluorine compounds make to the agrochemical industry. Our database covers 424 fluoro-agrochemicals and is subdivided into several categories including chemotypes, mode of action, heterocycles, and chirality. This in-depth analysis reveals the unique relationship between fluorine and agrochemicals.

Selective synthesis of spirobiindanes, alkenyl chlorides, and monofluoroalkenes from unactivated gem-difluoroalkanes controlled by aluminum-based Lewis acids.

The highly selective synthesis of spirobiindanes, alkenyl chlorides, and monofluoroalkenes via the cleavage of inert C(sp3)-F bonds in unactivated gem-difluoroalkanes using readily available and inexpensive aluminum-based Lewis acids of low toxicity is reported. The selectivity of this reaction can be controlled by modifying the substituents on the central aluminum atom of the promoter. An intramolecular cascade Friedel-Crafts alkylation of unactivated gem-difluorocarbons can be achieved using a stoichiometric amount of AlCl3. The subsequent synthesis of alkenyl chlorides via F/Cl exchange followed by an elimination can be accomplished using AlEt2Cl as a fluoride scavenger and halogen source. The defluorinative elimination of acyclic and cyclic gem-difluorocarbons to give monofluoroalkenes can be achieved using AlEt3.

Activation of Saturated Fluorocarbons to Synthesize Spirobiindanes, Monofluoroalkenes, and Indane Derivatives.

Fluorinated organic compounds are produced in abundance by the pharmaceutical and agrochemical industry, making such compounds attractive as building blocks for further functionalization. Unfortunately, activation of C(sp3)-F bond in saturated fluorocarbons, especially for aliphatic gem-difluoroalkanes, remains challenging. Here we describe the selective activation of inert C(sp3)-F bonds catalyzed by B(C6F5)3. In hexafluoro-2-propanol (HFIP), chemically robust aliphatic gem-difluorides are converted in high yields to the corresponding substituted 2,2',3,3'-tetrahydro-1,1'-spirobiindenes via a B(C6F5)3-catalyzed intramolecular cascade Friedel-Crafts cyclization, not requiring a silicon-based trapping reagent. However, in the absence of a hydrogen-bonding donor solvent such as HFIP, the aliphatic gem-difluorides preferentially engage in a defluorination/elimination process that provides monofluorinated alkenes in good yields. Furthermore, a series of substituted 1-alkyl-2,3-dihydro-1H-indenes was obtained in high yield from the B(C6F5)3-catalyzed defluorinative cyclization of aliphatic secondary monofluorides in HFIP. The protocol could inspire development of a new class of main-group Lewis acid-catalyzed C(sp3)-F bond activation in general unactivated fluorocarbons.

Host Cell Prediction of Exosomes Using Morphological Features on Solid Surfaces Analyzed by Machine Learning.

Exosomes are extracellular nanovesicles released from any cells and found in any body fluid. Because exosomes exhibit information of their host cells (secreting cells), their analysis is expected to be a powerful tool for early diagnosis of cancers. To predict the host cells, we extracted multidimensional feature data about size, shape, and deformation of exosomes immobilized on solid surfaces by atomic force microscopy (AFM). The key idea is combination of support vector machine (SVM) learning for individual exosome particles and their interpretation by principal component analysis (PCA). We observed exosomes derived from three different cancer cells on SiO2/Si, 3-aminopropyltriethoxysilane-modified-SiO2/Si, and TiO2 substrates by AFM. Then, 14-dimensional feature vectors were extracted from AFM particle data, and classifiers were trained in 14-dimensional space. The prediction accuracy for host cells of test AFM particles was examined by the cross-validation test. As a result, we obtained prediction of exosome host cells with the best accuracy of 85.2% for two-class SVM learning and 82.6% for three-class one. By PCA of the particle classifiers, we concluded that the main factors for prediction accuracy and its strong dependence on substrates are incremental decrease in the PCA-defined aspect ratio of the particles with their volume.

Asymmetric Alkylthienyl Thienoacenes Derived from Anthra[2,3-b]thieno[2,3-d]thiophene for Solution-Processable Organic Semiconductors.

Anthra[2,3-b]thieno[2,3-d]thiophene (ATT), which is readily accessed from thieno[3,2-b]thiophene and 2,3-naphthalenedicarboxylic anhydride, allows for selective substitution at the terminal thiophene ring, thereby providing asymmetric monoalkyl and monoalkylthienyl thienoacenes. Alkyl-substituted ATT (CnATT, n = 6, 8, 10, 12) has characteristics of a p-type field-effect transistor (FET), with mobility on the order of 0.01 cm2 V-1 s-1, which is the same as ATT. Conversely, alkylthienyl-substituted ATT (CnTATT, n = 6, 8, 10, 12) exhibits FET mobility of 0.15-1.9 cm2 V-1 s-1, which is up to 2 orders of magnitude greater than that of ATT and CnATT. Moreover, CnTATT forms crystalline thin films both by spin coating and drop casting, and C8TATT in particular exhibits a mobility of up to 1.6 cm2 V-1 s-1 in the drop-cast film. X-ray diffraction patterns of CnTATT thin films indicate that the molecules become oriented edge-on at the substrate surface with a highly ordered structure in the in-plane direction. Accordingly, CnTATT serves as a solution-processable p-type organic field-effect transistor, where the additional thiophene ring contributes significantly to the highly ordered thin-film structure and the high carrier mobility.

Electrochemical Self-Assembly of Nanostructured CuSCN/Rhodamine B Hybrid Thin Film and Its Dye-Sensitized Photocathodic Properties.

Nanostructured hybrid thin films of CuSCN and rhodamine B (RB) are electrochemically self-assembled (ESA) by cathodic electrolysis in an ethanol/water mixture containing Cu2+, SCN-, and RB. By selecting the solvent, Cu2+/SCN- ratio, and the concentration of RB, we demonstrate several control parameters in the film formation. High loading of RB into the film has been achieved to reach a CuSCN:RB volume ratio of approximately 2:1. The RB solid could almost completely be extracted from the hybrid film by soaking the film in dimethylacetamide (DMA), leading to a large increase of the surface area. The crystallographic orientation of the nanostructure with respect to the substrate can be controlled. Efficient quenching of fluorescence of RB has been observed for the CuSCN/RB hybrid film, implying hole injection from RB excited state to CuSCN. Photoelectrochemical study on the porous crystalline CuSCN obtained after the DMA treatment and sensitized with RB revealed sensitized photocathodic action under visible light illumination, indicating the potential usefulness of the porous CuSCN electrodes for construction of tandem dye-sensitized solar cells.