Interaction effects on uptake and toxicity of perfluoroalkyl substances and cadmium in wheat (Triticum aestivum L.) and rapeseed (Brassica campestris L.) from co-contaminated soil.

A vegetation study was conducted to investigate the interactive effects of perfluoroalkyl substances (PFASs), including perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), and Cadmium (Cd) on soil enzyme activities, phytotoxicity and bioaccumulation of wheat (Triticum aestivum L.) and rapeseed (Brassica campestris L.) from co-contaminated soil. Soil urease activities were inhibited significantly but catalase activities were promoted significantly by interaction of PFASs and Cd which had few effects on sucrase activities. Joint stress with PFASs and Cd decreased the biomass of plants and chlorophyll (Chl) content in both wheat and rapeseed, and malondialdehyde (MDA) content, superoxide dismutase (SOD) and peroxidase (POD) activities were increased in wheat but inhibited in rapeseed compared with single treatments. The bioconcentration abilities of PFASs in wheat and rapeseed were decreased, and the translocation factor of PFASs was decreased in wheat but increased in rapeseed with Cd addition. The bioaccumulation and translocation abilities of Cd were increased significantly in both wheat and rapeseed with PFASs addition. These findings suggested important evidence that the co-existence of PFASs and Cd reduced the bioavailability of PFASs while enhanced the bioavailability of Cd in soil, which increased the associated environmental risk for Cd but decreased for PFASs.

Facile One-Step Fabrication of Ordered Ultra-Long Organic Microwires Film for Flexible Near-Infrared Photodetectors.

Micro/nanoscale electronic devices, such as transistors and sensors, made from single-crystalline organic micro/nano-structures with tunable molecular/structural design are much smaller and more versatile than those that rely on conventional polycrystalline/amorphous organic films, but their development for mass production has been thwarted by difficulties in aligning and integrating the organic crystals required. Here, we developed an improved evaporation induced self-assemble method to accomplish large-area uniform growth of ultra-long methyl-squarylium (MeSq) microwires (MWs) films. The MWs could align along the dewetting direction of the solution with length over the entire substrate, thus lessening the requirement for precisely addressing the positions of MWs. Near infrared (NIR) photodetectors based on the ordered organic MWs film were directly constructed on Si/SiO2 substrate. The MeSq MWs showed high sensitivity to the NIR light with excellent stability and repeatability. To evaluate the potential applications of the organic MWs film in flexible and transparent electronics, flexible photodetectors were constructed by transferring the MWs film to polydimethylsiloxane (PDMS) substrate. Significantly, the device showed good flexibility and could stand a large bending stress due to the superior mechanical flexibility of the organic MWs. This characteristic opens new prospects for the applications of the MeSq MWs.

Controllable synthesis of 6H-1,4-diazepine-2,3-dicarbonitrile nanocrystals and their optical properties.

Organic nanostructures of 6H-1,4-Diazepine-2,3-dicarbonitrile (HDD) ranging from nanoparticles to nanoribbons have been controllably prepared. Changes in morphologies are observed to be accompanied with changes in optical properties. The HDD nanoparticles show a main emission at ca. 710 nm with a very weak shoulder at 625 nm, as nanoparticles gradually grow into nanoribbons, the predominant emission shifts to be centered at 625 nm at the expense of that at 710 nm. Shifts in the emission are proposed to come from different charge distributions of highest occupied molecular orbits (HOMO) induced by changing of intermolecular interactions, which is also evidenced by the quantum mechanics calculations.

Correlation of angiotensin I-converting enzyme gene insertion/deletion polymorphism with rheumatic heart disease: a meta-analysis.

Rheumatic heart disease (RHD) is a serious cardiovascular disorder worldwide. Several articles have reported the effect of angiotensin I-converting enzyme gene insertion/deletion (ACE I/D) polymorphism in RHD risk. However, the results still remain inconsistent. The objective of the present study was to assess more precise estimations of the relationship between ACE I/D variant and RHD susceptibility. Relevant case-control studies published between January 2000 and 2016 were searched in the electronic databases. The odds ratio (OR) with its 95% confidence interval (CI) was employed to calculate the strength of the effect. A total of nine articles were retrieved, including 1333 RHD patients and 1212 healthy controls. Overall, our result did not detect a significant association between ACE I/D polymorphism and RHD risk under each genetic model (P > 0.05). Subgroup analysis by ethnicity showed no positive relationship in Asians as well (P > 0.05). With respect to the severity of RHD, our result found that the frequency differences between mitral valve lesion (MVL), combined valve lesion (CVL) and healthy controls were not significantly different. Furthermore, no significant association was found between female, male RHD patients and the controls regarding to the ACE I/D polymorphism. In conclusion, our result indicated that ACE I/D polymorphism might not be a risk factor for RHD progression based on the existing research results. Additional well-designed studies with larger samples are still needed to confirm these findings.

Large-scale assembly of organic micro/nanocrystals into highly ordered patterns and their applications for strain sensors.

Large-scale assembly of zero-dimensional (0-D) organic nano/microcrystals into desired patterns is essential to their applications. However, current methods can hardly apply to the 0D organic crystals because of their relatively large sizes and polyhedral structures. Here, we demonstrate a facile and convenient way to assemble organic single crystals into large-area two-dimensional (2D) structures by application of appropriate electric field (EF). The ordering of the 2D structure depends on the frequency and field strength of the external electric field. Furthermore, lithographically patterning electrodes offer an efficient way to assemble the crystals into controllable patterns. By tuning the electrode pattern geometry, various desirable patterns with variable microstructures can be achieved. These formed superstructures and patterns can be fixed on the electrodes through exerting an external direct current, which allows for the further utilization of the patterns. With assistance of adhesive tape, patterns could be transferred onto flexible substrates for constructing a highly sensitive strain sensor. This strategy is applicable to nonsphere organic crystals with different sizes to assemble at desired positions and construct highly ordered arrays in a large scale, which opens new possibilities of organic microcrystals application in new-generation electronic devices and sensors.

In situ integration of squaraine-nanowire-array-based Schottky-type photodetectors with enhanced switching performance.

Organic nanostructure-based photodetectors are important building blocks for future high-performance, low-cost, flexible nano-optoelectronic devices. However, device integration remains a large challenge, and the structure-dependent performance of the device has been seldom studied. Here, we report the in situ integration of 2,4-bis[4-(N,N-dimethylamino)phenyl]squaraine (SQ)-nanowire (NW)-array-based photodetectors by growing the organic NW arrays on prefabricated electrodes through an evaporation-induced self-assembly process. In contrast with ohmic-contact devices, asymmetric electrode pairs of Au-Ti were utilized to achieve the construction of Schottky-type photodetectors on the basis of organic NW arrays. Significantly, the Schottky-type photodetectors exhibited a significantly enhanced performance as compared to the ohmic-type devices in terms of their higher photosensitivity and switching speed. The presence of a strong built-in electric field at the junction interface, which greatly facilitated the separation/transportation of photogenerated electron-hole pairs, was suggested to be responsible for the superior performance of the Schottky-type photodetectors. More importantly, the organic NW-array-based devices also showed a higher sensitivity and reproducibility than that of the single NW-based devices, and they were capable of low-light detection. The investigation of the photodetector circuitry also disclosed a very low pixel-to-pixel variation owing to the average effect of the NW-array-based devices. It is expected that organic NW-array-based Schottky-type photodetectors will have important applications in future organic nano-optoelectronic devices.